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Physicist Trying To Send a Signal Back In Time
phil reed writes "University of Washington physicist John Cramer is attempting to send a signal back through time."
From the article: "We're going to shoot an ultraviolet laser into a (special type of) crystal, and out will come two. lower-energy photons that are entangled," Cramer said.
For the first phase of the experiment, to be started early next year, they will look for evidence of signaling between the entangled photons. Finding that would, by itself, represent a stunning achievement. Ultimately, the UW scientists hope to test for retrocausality — evidence of a signal sent between photons backward in time.
The test will involve sending one of the photons down 10 miles of fiber optic cable, delaying it by 50 microseconds, then testing a quantum-mechanical aspect of the delayed photon. Due to quantum entanglement, the non-delayed photon would need to reflect the measurement made 50 microseconds later on the delayed photon. In order for this to happen, some kind of signal would need to be sent 50 microseconds back in time from the delayed photon to the non-delayed photon. (Confusing? Quantum physics is like that.)
Yesterday
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So this is how Bif gets rich. I knew there was no Sports Almanac.
If Bush wants to kill the terrorists, he should jump off a cliff.
you bastards, he never did anything to you...
Test has succeeded!
Like how about if they just say that they solemnly swear to send it back to today a year from now, when they have it working.. then we'd already know if it works today!
The question is, would we then spend as much time on trying to figure out how to do it? How about if we then didn't make it, how would that affect... I mean how would that.. What would...
ANOTHER TIMEQUAKE!!! RUUUUNNNNN!!!
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....Cuz one could scale this technique to work on, say, the lotto results. The only way this can work, is if the measurement of the 1st photon, requires the 2nd photon....so the measurement can only be made after the 2nd photon has been 'modified'.
@BEGIN MESSAGE
@author 321260
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@subject I heard about this
@content Yesterday
@EOM
We recently had heard in the office over one of the Yellow Machine that's made by Anthology Solutions.
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You mean to tell me that it only just now occurred to someone to send an entangled photon through a spool of fiber and see how it affects its twin, which took a direct path?
Also, I thought entanglement couldn't be used to transmit information, as a consequence of Somebody or Another's Law.
Can anyone clarify just what this poorly-written and sensational article is actually saying?
I have a question: Is it legal to use a timetravel device to chea^H^H^H^Haid in winning the lottery?
If only it worked that way. Just because we can prove something is true in quantum physics doesn't mean it can be "upscaled" to the macro-universe. In short, even if this works it's a far cry from *you* being able to go back in time.
Formerly GNU/Anonymous Coward. This message has been determined to cause cancer in laboratory animals.
IANAP, but when I studied some basic quantum theory, I thought that one of the issues that arose in the EPR/Bell research was that in order for entanglement to be valid, it could not be used to transmit information, except via quantum teleportation, which has strong limitations due to being a classical information channel. Does anyone care to clarify for me?
Okay, we all know spooky action at a distance involves guaranteeing that one measurement can determine the outcome of another billions of miles away; but this cannot actually be used for communication because there is no way of fixing the state of one, just measuring it, forcing an eigenstate. But the article suggests that we are *setting* "wave or particle-ness" (what? What quantum state is that referring to?) on the photon travelling the extra distance and transmitting that information back in time to the photon that first hits the detector. eh?
Please type the word in this image: predict
640K won't be enough.
Gentoo Linux - another day, another USE flag.
It carries no useful information, and it's not going 'backwards in time'. It's just two entangled particles outside of each other's light cone. Once one particle is found to be in a certain state, the state of the other particle will be instantly known, but no information is traveling back in time or faster than the speed of light.
It would be cool to see it actually happen, since previous entanglement experiments have never put the particles outside of each other's light cone, but the effect is something that physicists have understood (as much as anything in quantum physics is) for decades. In the article one of them say they don't really expect it to work, but I'd guess this is for technical reasons. No one expects that it won't work for theoretical reasons.
That's if teleportation data can be sent with neutrons.
In short, even if this works it's a far cry from *you* being able to go back in time.
I'd settle for being able to send myself a short message.
LK
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
Yeah I remembered you wrote this. Boy, are you up for a big suprise. Your grandson and I had quite a laugh with the prank we pulled on you 2 years from now. Leaving a living T-rex in your garage, I guess you didn't expected that! Amazing how that nanoreplicator was able to fit a garage in your appartement in the first place.
If you could send information back through time (which is what the FA is all about) then there would be no need to physically travel back through time.
I don't think it's possible though, otherwise we would probably be getting messages from the future, wouldn't we?
[HEAD EXPLODES]
Iraq: war to save the U
From what I can understand the backwards-in-time measurement requires communication from one entangled photon to the other. This would allow faster-than-light communication which is the first thing you think of when you hear about entanglement. I thought it was well established that this was impossible since measuring one photon destroys the entanglement and you can never tell if you sent the signal or received it.
Can anyone explain how this experiment is different, and would it also allow for ftl comms?
Karma police, I've given all I can, it's not enough, I've given all I can, but we're still on the payroll.
http://en.wikipedia.org/wiki/Ronald_Malett
The importance of both of these projects is that if you can send photons back in time, you can send signals back in time, and send messages. For years people have wondered about temporal paradoxes and how they may be resolved. With a system such as these, paradoxes can be tested. We'll finally have an answer to the Grandfather paradox.
Even with paradoxes such as this, a temporal communication device would have incredible application. The scientist in the article might only be working with a few microseconds, but it sounds like that if you have a long enough fiber optic cable, you can send a signal as far back as you want. You might not be able to, say use it to prevent someone from having a fatal accident, since if the accident never happened, you would have never sent the message. But there are many useful applications, especially in forewarning events beyond human control. What if we knew exactly when and where every earthquake and hurricane was going to hit in a particular year? What if we knew rainfall patterns in advanced and could plan for draught ahead of time?
You wouldn't be able to use it to prevent the next 9/11, but you could probably use a temporal communicator to prevent the next hurricane Katrina disaster. The hurricane or earthquake will still devastate the city, but that doesn't mean there has to be anyone in it at the time.
If this could be scaled up to macro-timescales, then it would certainly put lotteries out of business (or at least the ones where you choose numbers in advance).
Rich.
It says "...The test will involve sending one of the photons down 10 miles of fiber optic cable, delaying it by 50 microseconds..." So the photon takes 50 microseconds to get to the end of the fiber optic cable. Who cares, when the "magic signal" is sent from one photon to the other they'll still exist in the same time. One will just be part way down a fiber optic cable.
have courage
IT Minister will tell us tomorrow... about 5,000 photons before ago
(yeh, that's english...)
http://it.slashdot.org/it/06/11/16/0323202.shtml
But, he will be caught off-guard when the Thai IT Coup of 2007 occurred
Captcha: sender
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
This is the last post of this thread. I have sent it backwards in time for your pleasure at this moment.
Instantaneous communication between two points in space no matter the distance. Great if you want to include other planets in the internet with very little latency. Also computers of tomorrow will be hooked up to these so all you carry is a laptop with a simple cpu and buy extra cpu power as needed.
I regret that I only have one mod point to give per post.
Quoting from:
http://en.wikipedia.org/wiki/Quantum_entanglement
Although two entangled systems appear to interact across large spatial separations, no useful information can be transmitted in this way, so causality cannot be violated through entanglement.
The slashdot editor's brains seem to be traveling back in time though... shame Dean Stockwell is tied up with Battlestar Galactica.
If you send a signal back in time, one will have to go back in time to verify that it has been received. And since you cannot verify this, you can either claim that the signal has been sent successfully and celebrate, or start new experiments to send people back in time to verify that the signals that have just been sent have been received. Once people verify that, experiments will have to be done to bring people forward in time to testify that they have verified that the signal just sent has been received back in time. How would one prove that anyways ?
A better experiment is to try and catch signals to be sent in future. You can verify that this signal is sent, once you have received it.
Critics will say that scientists, once they catch a signal, will ensure that the signal is sent in the future. But then critics are always there...
(Confusing ? Time related writing is like that)
This would be like posting a response before the initial post
And who says that can't be done?
They're sending a RANDOM signal back in time.
This would be like posting a response before the initial post
the only reason we would go back in it is to gain some money...screw science when you can always go back to it.
Great, such progress! No more worries soon about having missed an important television programme.
"oh' i forgot to put in the crystals."
Okay, for short times this clearly isn't an issue, but what if I respond to a message that hasn't been sent preventing a message from being sent in the first place.
This would be like posting a response before the initial post. It wouldn't make any sense at all! It's impossible.
If you sent a radio signal back to 1242, would they be able to read it?
Perhaps the reason why we haven't received a signal yet, is that the technology required to read the "transport method" hasn't been invented yet?
This was previously posted tomorrow.
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I don't think it's possible though, otherwise we would probably be getting messages from the future, wouldn't we?
Maybe we're already getting them.
http://en.wikipedia.org/wiki/John_Titor
My site
/John Titor unavailable for comment
I am the unwilling control for my Origin.
A deadline approaching ? Don't stress ! Just log in the quantum network and get the code you will write after the deadline !
I've heard that Microsoft is constantly trying to master that technology since 30 years. Sadly it doesn't work that well for them, hence the legendary late releases.
I have discovered a truly marvelous proof of killer sig, which this margin is too narrow to contain.
I actually graduated in quantum information, this is no news and it is wrong.
I explain my opinion:
- Entanglement has been observed, pairs of fotons and spin of electrons can be correlated in a manner impossible to describe in classical physics.
- The experiment described does not even measure entanglement, as you could achieve the same result classically:
Say I have a black ball and a white ball, I put one at random in a closed box, the other one in another box. Say the boxes are put 1000 miles away from each other, from the content of one of the boxes I can predict which ball is in the other one, as I can check later.
The point is that they are not choosing in which state (of polarization) the light will be in the moment they measure the first time. So they aren't going to send any message ever this way. To do it they would require a classical channel wich works as we expect...
For the proof of entanglement one must implement physically the Bell's system or the Greenberger-Horne-Zeilinger one (I have no link), and SURPRISE! it has already been done.
i knoooo weee need more power sarrge.... sumone get sum plutoniummm! we need a 21 gijawatt charge to make this worrkk!!
You're obviously not intimately familiar with the theory of relativity.
Once perfected, this will ensure first posts in /.
Quantum entangledness is fun.
We wouldn't be able to send messages back in time right now (for example, 2006 -> 2005 and warn everyone of Katrina). However, we would be able to launch a split photon signal into the "future", and then receive messages back. You only need to extrapolate the science to many, many, many miles of fiber optics and send out enough particles to generate simple morse code. (Not 1 particle and 50 ms, but 1000 particles and 10 days.) This seems like less of a stretch than many other macro applications in quantum land.
However, how does this effect course of events? Send a signal out as Katrina is forming, split, receive morse "levies break, many deaths, evacuate city" so we evacuate the city and butress the levies... but then there aren't many deaths and the levies don't break...
This is what happens in Timescape, by Gregory Benford! I wonder if this guy's read it? Certainly looks like he might suffer the same fate as the protagonists of the book - being labelled a crackpot!
If you decide when planning the experiment that you're going to put the second photon into state X, and then 50ms before you do so you observe the first photon going into state X, then arguably you've seen some communication going backwards in time, but no information. You knew that state X was going to be used anyway.
More interesting would be to measure the state of the first photon and use that to affect the second one. So if the first one goes to state X, set the second one 50ms later to state Y, and vice versa. Or fix up a random number generator to change the state of the second photon and then observe the first photon to predict 50ms ahead of time what the random number is going to be. I'd expect this kind of thing is impossible.
-- Ed Avis ed@membled.com
Wouldn't we know if the test was successful before we actually conducted it?
Hm, this is very interesting news. If it's possible to send information something more than 50 ms back, it could be very neat. You don't need a very complicated type og carrier to trasnsmit digital information, so imagine a digital broadcast sent back 200 years. Now that would really rock things.
That may be the core tho'. If it proves possible to send a cure for cancer back 200 years, imagine the impact for the future! Also, this is one of those things I suspect would not happen in nature on it's own, so we are entering a place where humans are truly walking into the unknown, as no such thing can be observed naturally. Perhaps we are actually at a point where time will go from linear to chaos since we can changes past events.
However, if you think about it, it appears logical that if you send something back, you will stop exsiting the moment you start, since time chages, thus no information is transmitted in the first place (:
Hrmz... back to work...
If they measure the non-delayed particle *before* the 50 ms have passed, the quantum state of the delayed particle will already be fixed at the time they get around to measure it.
On the other hand, if they wait 50 ms before measuring the non-delayed particle, they aren't really sending much of a signal back in time.
It isn't much use to send message back in time, if you aren't allowed to read them before the present time.
If it succeeds, then they'll know about it before they do it. Then again, if they do know it about it before they do it then they'll have to do it otherwise it'll create a paradox. No wait, if it does succeed then they can't NOT do it because they did do it.
I need to lie down.
Summation 2
Sending physical objects back in time is not the only way that time travel can be useful.
If this works out, it could be the beginnings of instantaneous communication to distant places. This would neatly do away with the need for autonomous (or semi-autonomous) robots for exploring Mars, as you could in principle drive a Mars rover in real time from Earth.
The financial community is well ahead of this, because I can see plenty of instances of buy-sell activity in selected stocks before the news that eventually moves the stocks occurs.
Now that we know it will work, so why should we do the work?
God spoke to me.
He says he has nothing to do with this.
Why is this modded funny?
Of course, in the clasical version of this experiment the crystal is usualy spherical with a diameter of about 20cm.
Oh yeah, that John Titor was definitely from the future. By the way, how's that Civil War going? Y'know, the one that started in 2004
But we know people in 1242 wouldn't be able to read it so we wouldn't send information that way.
just what is the other photon doing while the first one is swanning off around the 10 mile delay ring??? They don't just stand around, these things move fast... my head has just assploded with the paradox...
Donald 'Duck' Dunn: We had a band powerful enough to turn goat piss into gasoline.
If it works the possibilities are amazing. Claiming that we would already have messages from the future is wrong as you could not send any information back further than the start of that experiment. However take the lottery numbers.... Lets say you have available 1 light weeks lengt of fibre optic, or that you were doing it in space and 3.5 light days away you had a mirror that would bounce back a photo to its starting point without altering the quantum mechanical properties that makes this work. You send out pairs of entangled photons, one in each pair you measure now, the other you measure when it bounces back/comes out the fibre optic, in a weeks time. In a weeks time you do the measure ment in such a way as to set the bits to read out the lottery numbers (each number in its own 8 bit byte) Having decided how you are going to modify (by inspecting in the right plce) the photons in a weeks time (after you know the lottery numbers) you can now read off the bits from the other ide of the entangled pair.... Scale this up and you add a whole new parameter to a http GET request....
$_="Slashdotter";$syn="OTT";s;..;;;sub _{print shift||$_};s!ash!Perl !;s=$syn=ack=i;tr+LLEd+BLAH+;_"Just Another ";_
...would they then stop trying to send it, because they know it will work?
80 CC D8 AF AE D3 AB 54 B7 2E CE 67 C7
... back in 1985... or was it in 1955!?
oh hey, don't worry, John let me know who the major players in that were going to be and I had them "taken care of"
-- GWB
Einstein face for news about quantum physics is very funny, because he didn't aceepted it's existance. You know the famous phrase: "god dosen't play dices" :)
I only know people that live in the past. If this experiment will work I would know someone that actually lives in the future.
If it does work, you could receive the signal 50 microseconds before you send
It is easy to show that that can never happen in reality. If you saw the signal for instance 5 seconds before you send it, you would be able to decide to not send the signal eventually (and in such case you would not see the signal 5 seconds before -- you wouldn't see any signal at all). This is a simple proof of causality that cannot be "circumvented" or "defeated". Nothing can "travel back in time". Period.
I heard this Cramer physicist dude on the radio the other night. He's deadly serious, and he's for real. He's also looking to get financing for building a time machine for sending tiny bits of information back in time (and he's getting a fair amount, too). You'd need a transmitter and a receiver. What would it be worth to find out that the Challenger mission was going to end badly (that was one of his examples)?
My biggest fear would be that the system works, and we start getting messages from 5 years from now 8 years from now, but ten years from now...nothing.
You are welcome on my lawn.
For Petes sake, we need 1.81jiggawats for this to happen.
And keep in mind, DO NOT CROSS THE STREAMS!!!
If I am not mistaken, geographically 50 seconds ago The test will not be in exactly the same position due to earth rotation and change in orbit around the sun, Although miniscule are they compensating for this actual position change? Maybe they are succeeding yet only the broom closet or china knows? hmmm
It needs a flux capacitor and 1.21 "Jiga"-Watts. Apparently invented by a Doc Brown.
well smart one, maybe he's not from english speaking country ;)
Let me guess... The decoded signal will read, "Save the cheerleader, save the world."
Just a thought... but for the instant transmision of information then it isn't necessary that the transmission of data goes back in time...
All you need to do is send BOTH photons from the pair each down their own fibre optic wire, when you fix one of them by measuring it, you will be able to instantly measure the other one. The information would have passed instantly between the two - however if the fibre optic was in a stright line, each going oposite directions, after 50ms a signal would be instantly transmitted from one photon to the other - but it would take light 100ms to travel that same distance as the information....
Still violates Einsteins assertion that information cannot travel faster than light... (I seem to remember him conceeding that tachyons could exist but they could never hold information and would always be purely random)
I wonder what will happen!
$_="Slashdotter";$syn="OTT";s;..;;;sub _{print shift||$_};s!ash!Perl !;s=$syn=ack=i;tr+LLEd+BLAH+;_"Just Another ";_
Spammers are already able to do this, I get mail which is sent in 2007 from them all the time!
We could only receive messages from the future using this technology as long as we are trying to detect them, since no one has done this experiment before (according to the article), no one has so far received messages from the future.
If he successfully sent a signal back in time, wouldn't we already know about it? :)
Because apparently one of the mods has faced the dilemma of trying to choose which woman to date and picking the wrong one.
I didn't need to explain any further.
LK
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
Why would you want to go back in time?
Going back in time would just mean you need to wait even longer for the Nintendo Wii to come out...
Could actually have been caused by humans sending explosive signals back in time? ;)
And George Bush keeps hoping that the next leap will be his last....
"They're sending me to the Vietnam.... It's a whole 'nother country...."
"All great things are simple & expressed in a single word: freedom, justice, honor, duty, mercy, hope." --Churchill
Don't marry her.
The thing is that you have to create the entangled beam and leave it in an entangled state for some years. Then when you do change it you can get the information in your time. But you cannot be getting the signals from the future without elaborate preparations.
Awesome! Sounds like it means we won't have to wait until 2546 to crank prank call people in the past!
You just got troll'd!
... you can't stop the Signal...
:D
Firefly r00lz
Okay two questions come to mind. First you have to the ability in the past to receive said message, and then you have to follow said message, and send it again. If you sent it via email it would mostly likely end up in your spam filter and lost to you. hence useless.
As the mesage would be filled with phrases like buy IBM on this date, short sell MSFT on this date buy it back on this date. Buy Apple on this date, etc.
i thought once I was found, but it was only a dream.
All these posts and not one obvious reference to a knowledged source:
I know which type of cristal is this, doctor Freeman...
The whole idea of this experiment seems that they're just delaying the signal and calling it time travel. What the hell?
Also, why does everyone keep saying that time reverses when travelling faster than light? Again, what the hell? The only reason behind this assumption is because light is the fastest thing we can measure (and thus anything faster than light will register as being in two places at once, or even at the destination momentarily before the subject "departs"). Am I just stupid, or is modern science wrong? I think both.
"Great Scott!"
- Dr. Emmett Brown
If, as has been suggested, you need a transmitter and a receiver, the quantum messages might already be out there, we just can't read them. Kind of like sending a book back a hundred thousand years and being surprised that Neanderthals don't get the warning.
-----------------------
Anyone who says that they can contemplate quantum mechanics without becoming dizzy
has not understood the concept in the least.
-- Niels Bohr
*"Cogito Ergo Liberalis"*
That's like saying in 1870 that radio waves are impossible because nobody's received any. There weren't any receivers then. Or like saying neutrinos didn't exist before there were detectors for them. It's quite possible that the as soon as we have something that can receive such messages it'll be flooded with spam from the future.
Anyway, I've thought about time travel rather more than anyone probably should, if you're interested. I address that point and a lot of others.
PHEM - party like it's 1997-2003!
If you're going to have given people grammar advice, at least have done it correctly: you're using the the present ultraconditional subinverted sem-active past subjunctive deponent aorist, so that should have been "scrodding".
In this rather good novel a physicist attempts to use tachyons to send a signal back in time to stop a runaway ocean pollution reaction that kills off a lot of life on earth. They calculate where the earth was at a particular point in time and space decades earlier, where another researcher had an experiment set up. He thinks he's getting some random interference until he starts noting down the times and then realises it's Morse code. Quite a good story, surely others here have read it?
It would be pretty easy (relativly) to make a message reciever. Once we make that we can get messages from the future. Here is how I see it working, we set up the device used in the test, but instead of sending one photon into a cable delaying it 50 micro second we loop the end of the cable to the front, so we delay it basicly forever. Now when sombody ends the loop in the future the photon changes its state in the future. The other photon is read the moment its split. According to the article, if it works (probably not) we can instantly read the 'future' state of the photon. Thus reading what somebody will do with the fiberglass line in the future. Well, anyway, the internet would become pretty fast when we could instantly change photons from miles away :)
My blog: http://www.redcode.nl
I'd settle for being able to send myself a short message.
Yea, I could see that.
1. Don't eat the shellfish.
2. Don't go home with Samantha. Or her twin.
3. Buy $x stock Tuesday, sell Friday
4. $1000 on the Cowboys to win by 3 points
I can't remember where I read it, but someone once said that the best evidence that time travel into the past isn't possible is the sheer lack of tourists from the future.
Tequila: It's not just for breakfast anymore!
How easy would this be to know if you got it right before you even tested it. If you did it right then you would have the results before you even tested it. If you didn't do it right, then you would have the results. Then again, do you still test even if you didn't get the results since you know the test is a bust, or do you not even test at all and wonder if the reason you never got the results is because you never tested?
Can I bum a sig?
AH-HA!
That's what all the gibberish spam is! It's us sending ourselves messages from the future!
Of course, this means that in the future, we will all need giant penises and breasts to fight off the alien invaders, but we can finance the purchasing of the pills needed by buying penny stocks, consolidating our bills, and refinancing our homes... Of course, it also means that we will all be impotant, and need to purchase viagra in order to keep our species going...
It's all so clear to me now...
Nephilium
"Even on Central Avenue, not the quietest dressed street in the world, he looked about as inconspicuous as a tarantula on a slice of angel food." -- Farewell, My Lovely (Chapter 1)
Good thing, the last think 'merica needs are a bunch of damn Goobacks comin' back here and taking our jobs!
Tequila: It's not just for breakfast anymore!
090309
-LK
time: the stuff that keeps everything from happening all at once.
already read this in the mysterious future.
Do you really mean "occurs" or do you mean "is reported to have occured" ?
I expect the only use for this technology would be for making crank calls to people in the past.
Using the Crank Call Time Phone tm. for any other purpose may end you existence.
How could you design an experiment that proved that you sent information backward in time?
You could generalize the way experiments are made this way: you formulate a null hypothesis (e.g. a signal was NOT sent back in time), then take a series of steps which disprove that hypothesis:
(a) do something
(b) make observations
(c) repeat variations of a & b
(d) make the observation that disproves the null hypothesis.
Thus a typical experiment goes a,b,c,d. In any experiment sending information backward in time, the steps would be b,a,c,d.
From a certain standpoint, you may conveniently consider things traveling backing in time as the most economical description of what is going on. But can you really show thta information has travelled back in time this way?
How do you know the observation you have made in (b) isn't what determines the observation you made in (d), instead of what you did in (a)? In that case, all you've done is a variation on the usual spooky quantum entanglement demonstration.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
You are fooling with the fabric of time and space, you stupid-------
ignorieren Sie das oben genannte, alle ist gut, vielen Dank mein Führer!
If Slashdot were chemistry it would look like this:Cadaverine
Come on, there are loads of languages in which "photon" is spelled with "f" at the beginning. You can imagine, that other nations have universities, where you can graduate in "quantum information", can't you? For a non-native speaker, this kind of spelling errors is very common. So what?
It's my understanding that quantum entanglement can't be used to transmit any useful information. Just because Particles A and B have opposite properties, doesn't help us. If we find that particle A has positive spin, we know that particle B, wherever it may be in the universe, must have negative spin.
I really don't see how that's any different than me having two playing cards, one red and one black, and you selecting one of the pair at random and taking it halfway around the world. As soon as I look at my card, I instantly know the colour of your card. But that's not transmitting any information -- all I did was solve a simple equation.
Je fume. Tu fumes. Nous fûmes!
To figure this out, you need to understand the relationship between the models of science and the real world. Clearly there is a direct and very thorough correspondance between the two, because after all our goal in science is to make the correlation between predictions and observations as strong as possible.
:-)
But there's a huge gulf between saying that and then making a leap into assuming that our models directly reflect the structure of reality. They don't. We don't know anything about the actual structure of reality at all, and have no means of ever knowing anything. It's all entirely indirect, and in a funny sort of way, purely circumstantial.
That's no hardship at all in science, in fact it's an opportunity --- it means that we can refine and redefine our models for all eternity, and hence achieve ever greater things. Arriving at a final Truth is simply not possible, not even in infinite time, because models are just models, and never the real thing. A rather cute observation that hammers home this point is that reality doesn't even use mathematics --- it's purely our own invention, the clockwork for our scientific models.
Given the above, the explanation for the quandry created by TFA can be explained pretty simply (although not particularly accurately, as Godel applies here): by Bell, the communication *must* be regarded as occurring across time, because if we don't think of it that way then our axiomatic framework in relativity breaks down, and we don't want that. So really, it's just a fudge to save the model, as it's a damn good (ie. useful) model.
But that doesn't say much about what's really happening.
If you think that's wierd, you're wrong. Science is full of submodels of limited applicability which can't be reconciled. That doesn't stop them from being the foundation of progress.
I am going to send back in time the way to decode my message.
What about transporting an entangled particle to the ISS? The point being time flows at a different rate the closer you are to a gravitational source. Even on a high mountain atomic clock run at a different rate than at sea level. Over time the difference in the entangled particles should keep increasing.
If anyone is thinking of traveling backwards in time, here is a simple reason why it is unlikely to happen. Assuming us earthlings have millions of years ahead of us, we have not seen a traveler yet from AD 1,000,000. If they actually will find time travel (backwards) wouldn't one of them visit us in the next million years.
But then this could be explained in many ways, the easiest being that we nuked each other at some point and took thousands of years of research down with it.
Ahh, i should get some sleep.
Life is just a conviction.
One simple CPU.
Do a calculation.
Send the result back in time - just a little.
Repeat until done!
Any quantum teleportation scheme requires the receiver to know what state the sender measured when the sender applied his measurement.
2 006QUA2HW5b.pdf (problem 5)--note that Bob needs to know which unitary state to measure on his quantum-teleported particle in order to complete the process.
Thus, the receiver certainly has some information about the *particle*, but has no information about the message until a classical channel carrying the state the sender measured catches up. So what's the value of this scheme? It's highly secure! If an eavesdropper intercepts the classical particle on the tandem channel, it's useless to them since the quantum-teleported state is effectively a one-time pad, being repeated ad nauseum!
In fact, if you're a physicist, maybe you'd appreciate seeing the Dirac notation of the process from my Quantum 2 class last year:
http://www.andrew.cmu.edu/user/bsauerwi/Problems/
~Ben
Yeah! And time can't slow down when you go close to the speed of light! And things can't act like both a particle and a wave! And particles can't tunnel through barriers they don't have the energy to escape!
For that matter, I'm not at all sure about these magical "fields" that act at a distance. And this whole "germ theory" of disease makes no sense - clearly it's just miasmas!
(Hint: you have not come up with a brand new objection to time travel, or even one that hasn't been answered before.)
PHEM - party like it's 1997-2003!
Once you're finished scratching your head over the quantum physics, you can really twist your noodle with the philosophy of time travel at http://www.omninerd.com/2006/11/14/coffeeshop/14 where we question if the very notion of time travel requires FATE and negates FREE WILL.
When you understand your disbelief in other gods, then you will understand my disbelief in yours.
Unless you believe in a god who has the power to touch his creation. The christian father god would probably say: You're trying to do what I can do, so in the event that you come close, I will crush you and make you understand that your power will never supercede mine. Or so that's what my parents believe.
Spending Resources on Defense leaves Less to defend.
*pacing* Come on! Cooooommmmmeee oonnnnnnnn!
Simple geometry shows that FTL travel or communication leads directly to time travel.
PHEM - party like it's 1997-2003!
Slashdotter tries to get laid!
Doesn't mean it's going to happen.
- For the complete works of Shakespeare: cat
If you send the photons back through the apparatus in the opposite direction would their signaling to each other occur in the future?
Warning: The Crank Prank Time Phone(tm) should only be used for prank calls to the past. Any other use is prohibited by law and may result in wiping you from existence.
You mean you don't have yours yet? My future self dropped one off to me a couple of weeks ago.
I decided I would send myself information from the future. I never got anything, so I figured it didn't work. So why would I waste my time and money on a project that already failed?
Suck my balls, Kyle.
Has noone ever seen the movie primer? If we sent a signal far enough back and they were somehow able to detect it, who knows what kind of paradox's will appear.
http://alternatives.rzero.com/
You mean the lack of poorly disguised tourists.
-Eric
SJW: Someone who has run out of real oppression, and has to fake it.
Why would you want to go back in time?
So I can get these little pills to my girlfriend!
69, dude!
I will be content when my grandkids were coming back.
Patents Drive Free Software as Hurricanes Drive Construction Industry
He sort of got it right. He got the country wrong where it's taking place, but American certainly started it.
They could send a robot back in time to protect Schrödinger's cat!
How do we know it hasn't? We already know how good the government is at cover-ups.....
Need to know basis, donchya know!
Remember when Windows were washed, mice were trapped and UNIX guarded the harem?
The major problem of time travel is grammar.
Lister: Oh, we don't exist here anymore!
Kryten: Actually, more correctly sir, we don't ever have existed here before. Although this is hardly the time to be conjugating temporal verbs in the past and possible never tense.
Personally, I'd settle for there being proof that something that was thought to be physically impossible is actually quite probable. We can worry about the whole sending ME back in the past later.
Buy Steampunk Clothing Online!
James P. Hogan's "Thrice Upon A Time" is about exactly this. They can't send physical objects back in time, but they can send information (using DEC PDP's!). They avert a disaster by sending information about it back to themselves before the disaster happened. If I recall the story correctly, they could only send a message back a certain interval, say three days, due to power and storage limitations. They ended up setting up a series of relays between earlier versions of themselves in order to leapfrog a message back to the beginning of the project, several months prior to the disaster.
1. Profit 2. Invent time machine 3. ...?
(Confusing? Quantum physics is like that.)
Quantum physics mixes very well with philosophy and LSD!
Two entangled photons actually occupy the same point in space. If u stick a stopwatch on each photon, u see that no time elapse when they move at lightspeed. This equals no distance (dist=velocity*time). Therefor they touch eachother, so no information is sent, since they are on the same spot, eventhough they cover some distance.
1) Design a project (that will work) to send back a random signal
2) Set the date that the signal will be sent in the future
3) Set up some observation equipment to read the signal
4) If your observation equipment manages to get the said future signal you know it works
5) Destroy the transmitting equipment before the day that you are to send the signal back
6) Wait
This is obviously retarded speculation.
hmmm. I wonder if the original data collected from the observation equipment would magically disappear? Better ask the Doc...
$ cat
cat:
4,8,15,16,23 & 42
He stated that his plane (or worldline, if you prefer) experienced a civil war in 2004. He also stated that this may or may not happen here, and that his even talking about it influenced it's probability. Do you really think a civil war was utterly out of the question after that sham (fine, disputed and suspicious) election?
On the topic of information transfer, it is thought that actually communicating information via entanglement is not possible. One can observe that something happened, but not whether that something represents a 1 or a 0. Whether or not that holds true remains to be seen.
On the topic of quantum uncertainty in the brain: there are proteins in the brain which enclose single electrons within an undisturbed volume of space sufficient to sustain quantum effects. Also, the structures that hold cells together (often referred to as the cellular skeleton) are hollow, with enough space for a single electron to pass through at a time. The same structures extend throughout the body, forming a network ('series of tubes'?) which could conceivably carry quantum information throughout the body. Some scientists have even theorized that this structure provides additional processing power to the brain, and that the loss of a portion of this network may be related to symptoms of phantom limb syndrome. As before, whether or not that holds true remains to be seen.
-1 raving lunatic; +6 subGenius... Things even out...
First time responder, long time lurker. I always wondered why the voices in my head warned me against eating the 12 spice Mexican fiesta plate last week. (I ignored and ate; I got sick.) So if that is my future self telling me something that trivial, then I truly have a lame future self.
Why don't these physicist vow to send themselves a signal from the future after they figure out how this work? That way, instead of wasting effort trying to make something that may be impossible happen, they can sit back and wait for word from their future selves whether it worked or not...
Hey, so who here remembers how Cramer promoted Twistor?
... ohmygod ... when? 1993-ish? He was plugging the book in the credits. Then I looked for it for years until I finally found it. I remember sending him an email note about it and getting a nice conversational reply.
I heard about his book by using his excellent periodic table Hypercard stack back in
His second novel, I bought at an airport newsstand at a "special price" of $1.99 or $2.99. Wow! Who has ever bought a new book, a readable one no less, in an airport for under $3.
I can't remember where I read it, but someone once said that the best evidence that time travel into the past isn't possible is the sheer lack of tourists from the future.
If time travel were possible, causality would still have inherent massive negative feedback (i.e., self-healing) in the loop. IOW, if you made a change in the past that altered the future, you might not even exist in the altered future, rendering that change undone (or un-doable?). This might render time-tourists undetectable, because they would not be able to make any detectable changes.
Ouch, that made my brain hurt.
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Why don't they just use a flux capacitor and be done with it? ;)
IANAQP. Can you change the particle from a known state to something else? Or do you not know the initial state beforehand? If so you know and can change the state, you would be able to send a message. It is either the predetermined known state (1) or not (0). A binary message.
Bush: He's Liberal in all the wrong ways.
I heard about it tomorrow.
Your future self is a dick! My future self dropped mine off when I was 8 , along with all of the games I would want to play.
Wasn't your future self smart enough to do that?
Freedom is assumed. Then they try to take it away. The degree to which you resist is the degree to which you are free.
Prof. Cramer home is here and the quoted article could be this one. It's a little bit older than expected!
Maybe Computers will never be as intelligent as Humans.
For sure they won't ever become so stupid. [VR-1988]
1.21 gigawatts? 1.21 gigawatts? Great Scott!
was how Half Life started.
[Enter fun stuff here.]
Sounds like hogwarsh to me.
The time dimension does not exist.. time is only a product of our minds and perception.. the only way we can go back in time is in our minds through memories .. for a rock time does not exist
I fuse with Mercer every single day...
This is the John Cramer from Feb 2004. In Feb 2007 you cascaded 10^12 of these units and sent a msg back to Feb 2004. By replying to that msg I will have altered your future time line and the experement in 2007 will fail and this msg will not be sent. That's why you/we don't remember receiving it in 2004. Dude, Messing with casualty is sure confusing.
..
..
ps: By the way, the answer is 42
pps: The next Pres. is Mick Jaguar and his VP is Pee-wee Herman
davecb5620@gmail.com
Best thing about this is that they will know in advance when/if they succeed!
OOO! Pretty light! We will succeed with the next run!
Then someone will cause a paradox by trashing the equipment, thus destroying space-time as we know it.
A lot of my spam comes from the future!
http://outcampaign.org/
If it did, it was probably ignored as "Static." There is also the other problem of a "Negative Propogation Delay"...
Seriously, imagine how much money you could save yourself on special shampoo if you could just send back that little text message "don't do it, she has crabs."
Judges and senates have been bought for gold; Esteem and love were never to be sold.
Wouldnt we know allready ?
Seriosly if time travel is true we would have evidence of it.
6) Someone will welcome their time traveling overlords.
50 microseconds is a huge market advantage.
The major problem is quite simply one of grammar, and the main work to consult in this matter is Dr. Dan Streetmentioner's Time Traveller's Handbook of 1001 Tense Formations. It will tell you for instance how to describe something that was about to happen to you in the past before you avoided it by time-jumping forward two days in order to avoid it. The event will be described differently according to whether you are talking about it from the standpoint of your own natural time, from a time in the further future, or a time in the further past and is further complicated by the possibility of conducting conversations whilst you are actually travelling from one time to another with the intention of becoming your own father or mother...
To resume: The Restaurant at the End of the Universe is one of the most extraordinary ventures in the entire history of catering. It is built on the fragmented remains of an eventually ruined planet which is (wioll haven be) enclosed in a vast time bubble and projected forward in time to the precise moment of the End of the Universe. This is, many would say, impossible.
In it, guests take (willan on-take) their places at table and eat (willan oneat) sumptuous meals whilst watching (willing watchen) the whole of creation explode around them. This is, many would say, equally impossible.
You can arrive (mayan arivan on-when) for any sitting you like without prior (late fore-when) reservation because you can book retrospectively, as it were when you return to your own time. (you can have on-book haventa forewhen presooning returningwenta retrohome.) This is, many would now insist, absolutely impossible.
At the Restaurant you can meet and dine with (mayan meetan con with dinan on when) a fascinating cross-section of the entire population of space and time. This, it can be explained patiently, is also impossible.
You can visit it as many times as you like (mayan on-visit re-onvisiting... and so on-for further tense-corrections consult Dr. Streetmentioner's book) and be sure of never meeting yourself, because of the embarrassment this usually causes. This, even if the rest were true, which it isn't, is patently impossible, say the doubters.
"When the atomic bomb goes off there's devastation...but when the atomic bong goes off there's celebraaaaation!"
Maybe it's that way because we don't have a time machine yet, and they don't want to be making a one-way trip.
Or we'll all be raptured in a few years, and so we don't have time to develop it.
I really hope it works, despite that it does not add up to me. Faster-than-light communication would really revolutionize a lot of things on this planet and, eventually, beyond.
Assuming that this would work, would anyone believe it? Since this technology didn't exist in the past, why would anyone assume that a message "From The Future" was legit? Who's to say we haven't already recieved messages from the future, but we either don't know we're recieving them or don't believe them? If back in 2004 George W. Bush, FEMA, the Coast Guard, and everybody else recieved a message "From The Future!!" saying that a powerful hurricane would hit the US and devastate New Orleans and the surrounding areas, would they believe it?
Brownie: "Mr. President, we have recieved a warning from 2012 saying that a big hurricane is going to destroy New Orleans next year."
Dubya: "What? 2012?! Brownie, what the hell are you smoking? You're doing a heckuva job, Brownie..." (eyes rolling)
Or what if the message caused the powers that be (were?) to take a course of action that caused even greater harm/problems? Just keep sending messages earlier until we (they?) get it right?
"Alright, look people, we've been sending messages back to you from the future so you can avoid a catastrophe, but you keep fucking it all up!"
Now my family photos are all fading out.
Slashdot summaries are like that.
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
The problem with entanglement is that while it implies all sorts of spooky stuff, the spooky
stuff is well hidden. The first photon they measure will show a given property, the second
one will show the same (or opposite) property as required for energy conservation. He won't
be able to prove that a signal went back in time.
Maybe we don't recognise them as tourists? Or, maybe saying that is just like some place like Elbonia saying they don't believe in any travel because they don't see tourists; maybe it's just that no one wants to go there. Maybe they know something we don't yet, and really want to avoid this time period.
Oh no, not again.
There havn't been any avalanches in CO lately have there?
I'm supposed to go dig my buddy out Saturday afternoon.
http://en.wikipedia.org/wiki/The_Endochronic_Prope rties_of_Resublimated_Thiotimoline
change is inevitable
Perhaps we can't send physical matter, but what about using this as the link in quantum teleportation?
How to enable garbage collection on a system without protected memory: #define malloc() ((void *) rand())
So this is what that talk about backward compatibility was about?
and you forget to send it later, does that cause the universe to implode?
Magic doesn't work in my presence. My power of disbelief is too strong.
Science H. Logic, you're right!
Does Anybody Here Remember When Hanz Gubenstein Invented Time Travel?
I have no
The validity of science is itself is based upon acceptance of the laws of cause and effect. So, if you propose a theory that invalidates the laws of cause effect, and then prove it with science, well, at best you have a new paradox to deal with.
Say I have a black ball and a white ball, I put one at random in a closed box, the other one in another box. Say the boxes are put 1000 miles away from each other, from the content of one of the boxes I can predict which ball is in the other one, as I can check later.
---
Um, isn't it at least interesting that subatomic particles can be proven to work like black and white balls?
The classic problem makes this simple to explain. The fascinating part to me is that the interaction is actually that simple to explain.
Read the entire wikipedia entry... a) The setting was from a game b) the so called proofs have been debunked, one being a fairly old geiger counter, the other one a badly fotographed bent, chemical light unit like they sold it on the streets around the time titor appeared...
Trasferiamo Punto Informatico qui? ^_^
What are you talking about? YOu have never woken up to find your chair stuck in the middle of a wall?
Just need to Kill Hitler right after the VW factory is made.(if you kill him to soon, the hippies would have no shagwagon, and the VAG 1.8T is a sweet engine) Warn pearl harbor, and have them kick Jap ass when they show up, and we prob don't have the drop 2 nukes on them to tell them who is boss. Block the Titanic from going near that big piece of ice, and have them build it with better bolts, that movie blew!
wouldn't he already have gotten a message from himself? I think he should just give up now.
Without altering their state, that is? 8^|
I heard the guy too. That he was on the Art Bell show (awright, I was driving 1000 miles overnight and couldn't get any other station) does not bode well.
... hence the reason he was on Art Bell, and why we're discussing him on /. per an exciting-sounding but ill-expressed story.
Art asked something similar about "if it works, why aren't we getting any information from the future right now?" The excuse was that you can only send info back so far as the machine has been turned on. Ergo, no machine = isn't running = no winning lottery numbers.
The guy was obviously a crackpot.
Unfortunately, people who do not understand a subject adequately cannot differentiate between the crackpot's impressive yet incomprehensible rantings vs. your reasoned informed explanations of why the crackpot is wrong
Can we get a "-1 Wrong" moderation option?
I think you meant V1AGr@.
perl -e "eval pack(q{H*},join q{},qw{70 72696e74207061636b28717b482a7d2c717b343 637323635363534323533343430617d293b})"
Not to get to technical about hypothetical time travel, but Professor of Physics at the Univ. of Conn., Dr. Ron Mallett is one the leading physicists actually dealing with the plausibility of time travel. According to his work (and coincidentally John Titor as well) we can't actually go back or forward into our same time lines. We can go back to 1800 AD, but it we'd do so by side-stepping to a parallel 1800 AD, not ours own. We cannot traverse time in a reverse fashion, but rather step outside of it then step back in.
There would be discrepancies in the timelines for that reason. John Titor, for example, couldn't know exactly what would happen in our timeline but can only relate his own timeline which is basically an approximation of ours.
I for one welcome our back in time signaling overlords.
New Scientist covered this in an article several weeks ago. The experiment is about retrocausality - the future affecting the past - rather than sending information back in time.
A few weeks later they also printed a letter which suggested retrocausality was redundant.
I don't pretend to understand this stuff. The message I got from the article though was that the future affecting the past only seems weird because we assume that time flows, because that's how we perceive it: if you imagine all time existing like a spatial dimension, then retrocausality is "normal".
rt
You know.... We do one scalar operation and get a result, send the result back a few microseconds and use the result as input for the "next" operation, get a result, and repeat until we get an exit condition with an answer. Or you might wait forever if you get into an infinite loop. You'd get answers back either immediately or never.
Here is the quote:
Because these two photons are entangled, the act of detecting the second as either a wave or a particle should simultaneously force "
the other photon to also change into either a wave or a particle. But that would have to happen to the first photon before it hits its detector -- which it will hit 50 microseconds before the second photon is detected. "
The problem with that claim is they cannot force second photon to come out as they want (as particle or as wave) - it will come out completely at random. So because of that randomeness one can always claim that it was the first photon that defined the outcome of the second one. So even though wave function collapses at infinite speed the information is not transmitted.
Reminds me of James P. Hogan's excellent novel "The Proteus Operation".
... this sounds extremely similar to an experiment I came up with about 13 years ago, that completely convinced me I could send signals back in time. I even bought and assembled enough components to test large portions of the experiment in my garage. Everything except the generation of entangled photons; that takes more of a budget. I was still convinced it would work, until I went back to school and actually took some quantum mechanics courses.
Then I finally understood the elementary mistake I had been making. I find it difficult to believe a respected physics professor could make the same mistake. OTOH, I have shown my proposed experiment to very many extremely smart people, including physics professors, and very few have found the error.
Basically it seems like Cramer's idea is to send one photon on a pathway in which it intereferes with itself or not, as the experimenter chooses, which will then affect whether the entangled photon will have earlier interfered with itself. This doesn't work. You have to write out the QM to really see why. The actual math will depend on the specific experimental setup, but it sounds very likely to me that this is essentially the same experiment.
Anyone have a more technical description of the proposed experiment? (Or should I RTWFT)?
It was lame when Hawking said it*, and it still is.
Would you know if someone from a 1000 years from now was among us? if so, How?
If you went back 1000 year(presumably prepared and not randomly suck through a plot convention), I would think you could do a reasonable job of blending in. The real issue would be bringing a virus that we're not ready for.
*He is far smarter then I will ever be, he puts forth brilliant idea, but that doesn't mean he's perfect.**
|
The Kruger Dunning explains most post on
why r u being a buzz kill? we all know it is a quantum "theory". i rather go with the different possibilities for time travel that Hawking discusses. while i think most are just based on results of equations, like Einstein's solutions. so i am opting to think about applications other than the silly changing history crap to something more probable. what applications does sending a ray 5ms back in time have? huh? of course i am not a physics geek.
It's definitely possible to travel into the future in your own time line. In fact, it's pretty damn easy. I'll do it right now! Watch... ... ... ...
Voila, I'm in the future!
If you actually wanted me to travel "further" into the future, give me a spaceship that travels at 99.9999% of the speed of light and I'll see you in 1000 years. It's getting back that's the bitch.
Life would be easier if I had the source code.
It's not going well. A headline off Google News, dated November 12th, 2006, states: "Iraq's civil war claims 135 more lives". Granted, Titor did say "American civil war". But with America's occupation in Iraq, it could be considered America. And perhaps in the future Iraq becomes part of the US, thus interpreted as America in the future?
"Anyway, I've thought about time travel rather more than anyone probably should..."
What you've really done is summarize the thoughts of Kip Thorne and Stephen Hawking more than anyone probably should.
"they took yer job!"
500 dollar reward for tip(s) leading to the arrest of the person(s) who stole my sig.
Maybe we just haven't built the machinery to accept them.
Say we used this with a bunch of mirrors or flung a bunch of photons around a black hole, so that the time difference was much greater. Then when the photons get received by the Earth of the future they can change the photons, thus changing our entangled ones at this point in time.
The reason we haven't got any messages from them yet is that we haven't sent them any entangled photons to use yet, not because it isn't possible.
Okay, it's very crackpot, but it's just an example..
// MD_Update(&m,buf,j);
Send a message? That's old stuff, my priest did that last year when he sent a message back to the Elders so they would ssend him a message via the Tree of Cadence.
Call it "science" and it is cool, and everyone is interesting even in the fringe. Call it religion, and it is immediately dismissed as nonsense.
Have you read my journal today?
Phase 1.
Build a recevier
Phase 2.
Listen for a signal
Phase 3.
If signal received, build a transmitter.
If no signal received, then experiment will be a failure. Go home.
Like, the 678s, that's gonna be the section on Web 3.0 technology, right?
Interested in a Flash-based MAME front end? Visit mame.danzbb.com
Might need a time traveling information receiver first.
If this experiment is successful, then the dreams of the members of the Ministry of Slashdot may start to synchronize. The dream will consist of the following: A shadowy figure appears in the doorway of an nondescript corporate office building. A static-y, fading voice-over says: "This is NOT a dream (not a dream). We are using your brain as a receiver. We are unable to transmit through your conscious neural interference. You are receiving this broadcast in order to alter the events you are seeing. We are transmitting from the year two-oh-one- (...). Our technology has not developed a transmitter strong enough to reach your conscious state of awareness. This is not a dream. You are seeing this picture ..."
Bill Gates emerges from the building holding both an Gen-3 XBox and a Zune II, which both proceed to bring hell on earth by sucking up all of the world's intellectual property into a Microsoft-specific DRM scheme.
It will never hapen since, techincally, if they had succeeded in the future we would have known about it already since they would have received a signal or maybe they did but it was received 10 years ago and the people in that room just thought that it was a weird flash.
From Wired (http://wired.com/wired/archive/14.11/sixwords.htm l):
... nobody there ...
Machine. Unexpectedly, I'd invented a time
- Alan Moore
TIME MACHINE REACHES FUTURE!!!
- Harry Harrison
Osama's time machine: President Gore concerned.
- Charles Stross
1) Your analysis is based on bad assumptions so your result is way off. 2) You're a sick bastard for fucking a horse.
Future Grammer Nazi's!
The Kruger Dunning explains most post on
Phase 1.
Build a recevier
Phase 2.
Listen for a signal for 30 years
Phase 3.
If signal received, build a transmitter.
If no signal received, then experiment will be a failure. Retire.
How great would that job be?
The Kruger Dunning explains most post on
The real problem is that you're sending arbitrary data. That's what was missing in my understanding. To send something over the entangled channel, it must be endemic to the state of the photon. E.g., 50/50 probability of spin up or spin down. If you attempt to force the photon into a specific state, the entanglement drops out and no message is sent, as I understand it.
Keep in mind that you can't just reuse all these photons. They all have to be disposable which means you have to have a very large supply of them and only use them for really important messages. How do you store entangled photons for long term use? How the hell do you know when to check the state of your photons? Cronjob? heh. How do you detect if a photon is still entangled without disturbing the state? If you can do all three of these, you could have a queue of photons labeled P0, P1, P2, P3, etc. If P0 is entangled, it's a 0. If it's not entangled, it's a 1. The message: P0:1 P1:1 P2:0 P3:1 P4:0 P5:0 P6:0 would equal "h" in ASCII.
I'm guessing that the third problem is the killer.
-l
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...without instantly changing the quantum state of the delayed photon? Am I missing something?
As soon as you measure an entangled photon, the other entangled photon of the pair has its quantum state immediately changed.
If photon one hits the detector 50 ms before the other 'delayed' photon in the optic cable, isn't it 'being measured'? If it is being measured, then it changes the second photon. Ergo, when the second one hits the moveable detector its state is predetermined by the first photon's measurement.
I keep trying to think of ways in which you could avoid this, for example, measuring the first one in a somewhat random fashion so that by constantly measuring #2 in a manner that produces a non-random result you could see retrocausality through #1's measurement not being random when it should be; however, I keep running into the 'as soon as #1 is measured, #2 is set' issue.
Lil' help?
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In quantum cryptography, for example, Alice and Bob want make sure that no Eve is eavesdropping. They can do this because they exchange information with entangled particles: Alice keeps one and sends one to Bob. If Eve has been tampering ("measuring") the Bob's particle, the measurement which Alice performs on her own particle will be affected. However in order for Alice to know if her measurement has been affected, she must also know the result of Bob's experiment: they must pick the phone up and tell each other the results of their experiment. Therefore - regardless of whether Eve's tampering has affected Alice;s measurement "instantanously", information cannot be exchanged faster than the telephone call, which is classical and must be slower than the speed of light.
In this experiment it seems to me the situation must be similar. The fact that one of the particles is delayed by 50 microseconds over 10 miles seems like no coincidence: in special relativity temrs an event 10 miles awayand 50 microseconds away is actually simulataneous (on the surface of the same light cone). Therefore this seems not to breach causality.
Why doesn't this guy stop what the hell he's doing and wait for the signal from the future so he can see whether or not his hard work will pay off?
-R
Should be 7 in the first line: There once was a lady named Bright...
What's this? Another weblog? On transit?
We could open a IPoST (IP over spacetime) daemon on jan 1 2009, and be able to receive messages from the future from that date on.
Being spammed from the present is bad enough, but being spammed from the future....
Imagine making payments - it would be like Douglas Adams's "Restaurant at the End of the Universe" - Just open a bank account under our name with a minimum deposit, and rest assured, your visit will have been fully paid from the accumulated interest over several billion years.
Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
If you suspend your disbelief for a minute, it isn't hard to imagine that with a few tragic events, a civil war could indeed have started out of the deep political divisions in the 2000 and/or 2004 election. The fact that it didn't doesn't conflict with what Titor claimed about different world lines at all.
The problem is that whomever Titor really was could have claimed just about anything and then it becomes possible to write off the failure of his "predictions" to materialize as a difference in world lines.
What is interesting is at least one of the things he said that seemed like it could have been an indirect mention of the tsunami disaster a little while back that did happen. I don't have a reference handy, but it didn't take much to connect the statement to the incident. I say this is interesting because the motion of the tectonic plates mostly isn't affected by any human activities by and large (as I understand it). Therefore, it isn't impossible to think that IF the world line theory is accurate that the motion of the plates might not vary much from world line to world line. So his mention of the event is a bit intriguing.
I am not suggesting his story is real, but that there is enough in his story to make me wonder with an imagination reminiscent of my childhood.
I'd bet that the only message people in the future will ever send to people in the past will be "Stop F*cking with time you retards!"
I was merely translating from the Dialect of the Future!
It's more proof that the messages are coming from the future...
Nephilium
why would some from 100 years from now even need a disguise?
OTOH, maybe coming back in time would bring a Flu strain that would wipe us all out?
The Kruger Dunning explains most post on
Because wearing a chordloo would raise more than a few eyebrows in 2006?
-Eric
SJW: Someone who has run out of real oppression, and has to fake it.
...ah, and thus begins the era of the DiLithium Crystal!
FIRST POST! ...
Damn
IANAP, but
They're going to measure one particle 50us before the other..
But upon the measurement of the first photon the state of the other is already known so we're talking about action going forward in time, not backwards.
And besides, they aren't sending any information at all as many people have already pointed out.
So actually I'd say that since there's no information being sent we can't talk about which direction through time it goes.
http://www.amazon.com/Thrice-Upon-Time-James-Hogan /dp/0671319485/sr=8-1/qid=1163699261/ref=pd_bbs_sr _1/104-7429885-2363911?ie=UTF8&s=books dealt with all these issues ... with Hogan's usual insight and wit. A good read, and apparently now an important one!
Here's Cramer's Alternative View column in Analog that goes into more detail:
http://www.analogsf.com/0612/altview.shtml
Cramer's no dummy, and the above article indicates that he believes that all of the "proofs" of the impossibility of sending signals had subtle flaws. Mind you, we've already seen that he doesn't expect this new experiment to work; it's just that nobody can figure out WHY it won't work.
"This is NOT a dream. We are broadcasting from the year 1999...."
http://www.amazon.com/Light-Other-Days-Arthur-Clar ke/dp/0812576403/ref=pd_sxp_grid_pt_2_2/103-842345 3-9537423
Light of Other Days - By Arthur C Clarke and Stephen Baxter . Goes over the long term implications of instantaneous communications, or being able to receive information/peer back in time. Great fascinating read!
But the same stipulates that the all powerful all knowing CFG already knew that this event would come about and created all the events leading up to this event to ensure its eventuality. Hierarchical religious doctrine falls hard on these swords of contradiction while trying to maintain absolutism.
that somebody here actually scored?
What would it be worth to find out that the Challenger mission was going to end badly but if you sent a message back in time to warn of the error of the mission, then the error would be fixed so the message would never be sent. so how would the error be fixed?
yes the idea is that the delayed photon is changed.
What they try to do is they choose with their moving detector how they want the delayed photon to be detected.
The question they try to answer: if we choose for example delayed photon to be detected as wave and we know that 50mksec earlier the other photon was detected as particle - will we be able to detect the delayed wave-photon ?
or maybe yes, but I don't see why they could send information this way:
detect spin change
wait a period of time(say 3ns)
Detect spin change
period of time 1ns
detect spin change 20ns.
couldn't the periods of time between changes be interpeted as information? Lest say the ns is determined by letters. So the above example would have spelled cat.
so you are transmitting information.
Now lets say one half of the entanglement is on a ship approaching the speed of light. You are sending cat to the past. or from the past.
QED
Where is my prize?
The Kruger Dunning explains most post on
They create two entangled protons...call them A and B.
They first send A into a detector that registers A as either a wave or a particle...spose its a particle.
Then 50ms later they choose to either measure B as a wave or as a particle. Measuring it as a particle they say would send a signal back in time to determine that the first one is a particle.
Obvious Problem: the quantum state of both the particles is determined AS SOON AS THEY DETECT THE FIRST PROTON A. At that point the quantum state has been measured and thus determined for both protons.
You could just as easily look at this experiment as sending a signal 'forward' in time from proton A to proton B.
Anybody else get that?
...two years ago an email. I'm going to do this by fiddling with the headers. I think my approach has roughly the same amount of good physics backing it as what these guys are doing, and I expect roughly the same amount of success. The advantage of my approach is that I'm going to get the same results for less money. Maybe I should create a startup...
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
I'd settle for being able to send myself a short message.
\MessageBegins\ It's a trap! \MessageEnds\
LK
It doesn't hurt to be nice.
There are a bunch of things that make this less useful for doing weird things:
You can't send a message back in time. You can only receive a message from the future. That is, you can only send a message back in time to a point where you had arranged to get it. It's like an box that you take stuff out of before you put it in; things go back in time to the point where you took stuff out, not to any other time. So there's no issue with the fact that we're not getting messages from the future; the time before the time machine is invented is inaccessible.
You can't tell what it says in the past. This is where quantum is weird. Basically, what happens is that person A receives the message, which is a series of dots to put in a picture. It looks like random static. Then person B sends the message, which consists of choosing, for each dot, "bell" or "bars". Then they talk to each other, and they find that if you look at only the "bell" dots, the picture is a bell, and if you look at the "bars" dots, it's a set of bars. Since all of the data is collected by A before B chooses, they have to come to the conclusion that something really weird is going on, and the choice later clearly affects the data that was already written down. But they can only come to this conclusion after the experiment is over; before the message is sent, the received message can't be interpreted, although all of the observations can be taken.
This of it like this magic trick: the audience gets a deck of cards with a variety of backs which they examine in detail. A volunteer on stage shuffled a second deck of cards, writes down a few numbers between 1 and 52, and draws the cards with the given numbers (i.e., for 10, draws the 10th card in the shuffled deck). When the volunteer announces the set of names, they all turn out to have the same backs in the audience's deck. The volunteer chose freely, the deck was really random, and the audience saw the fronts and backs of all of the cards in their deck before the choice was made. If the trick is repeated with fresh decks, it always works. We have to conclude that the volunteer is affecting the construction of the deck in the past, but we're only impressed after it's all over, and we have no idea what the volunteer is going to choose in advance. Even if we agree on a set of numbers to pick if the stock market goes up and a different set to pick if it goes down, we can't tell by looking at the audience's deck which it will be, but the trick still works.
Thanks to John's warning, the government showed up at my doorstop and took away my guns before I could start it.. ;-)
DEAD DEAD DEAD DELETE ME
Unfortunately it didn't work. How do I know!? No mention of contact from the future in ANY of the history books! It MUST be a conspiracy! ;-)
:-( --- argh. Despair, I owe again.
What about the fact that I've never received any message from the future dated after today? Now that's worrying.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
Yours is exactly the kind of experiment that I've been trying to understand in terms of why it won't "work." (That is, why information couldn't be transmitted backwards in time via the system proposed.")
Taking the practical aspects of the experiment out of the equation, and positing one in which the delay is (say) 10 minutes, or 24 hours rather than 50uS, what would prevent the backwards transmission of information, in theory?
Suppose the man at Ap took notes on which detector detected each photon, and then waited for a visit from the other guy, the guy at Ad.
Meanwhile, the guy at Ad, 10 minutes down the line, is measuring each photon with one detector or the other and marking which way he measured the photon. When he's finished, he goes and sees the man at Ap, and they compare notes.
So, do the notes match?
Okay, so what if they guy at Ap takes his notes and then goes across the hall (past the massive loops of fiber optics) and watches the guy at Ad. Is there something in that act that "breaks" the entanglement so that the outcomes no longer correspond?
One more basic physics question I have is this: if the photon goes through a medium, like a fiber optic (or glass, or water) is the photon that emerges "the same photon" that entered? Does entaglement survive the transmission?
--When you buy proprietary software, you don't get better software. What you get is the right to complain about it.
Great Scott! If they calibrate the time circuits wrong and do not apply the necessary 1.21 Jigowatts of electrical power, then the temporal causality loop could result in a paradox which completely destroys the Universe! This is heavy...
"If you do a measurement on one, it has an immediate effect on the other even if they are separated by light years across the universe"
How could they possibly know this? I can believe theorize this, but how could they possibly get enough distance to know this happens "immediately"?
I have tried to grasp how this could be used at all for communication, and I honestly just don't get it. The way I see it, you run one through a detector to see if it's a wave (or particle), and if it is then the other one also becomes a wave(or particle), no matter how far away in time or space it is. So it's like this... Say I have two marbles that can either be red or blue each enclosed in a box. But, they are neither red nor blue untill I open one of the boxes and look. The moment I look at one, and see that it is red, the other one also becomes red. Now... Lets say I have one of these special marbles, and my great great grandfather has one, back, say 100 years ago. I look at mine and see that it is red, therefore, his must also turn red. But, don't I still have to tell him what red means through some other form of communication? Like, say I want to send him 1 bit of information (true or false) with one of these special marbles. How will he know that red means true, or false... all he will know is that I also got red when I looked at mine. Unless I have a way of altering the state of mine (and thus altering the state of his too), I don't have any way of telling him that red or blue mean anything, thus I can't send him any information with this method. Can someone explain what I am missing here?
A good example of this theory exists in the film Primer. I highly recommend you see it if you haven't already.
Even people that believe in pre-destiny look both ways before crossing the street.
They are basing the idea that the information would have to travel back in time to make this work.
This is wrong!
Quantum entanglement theory states that what ever effects one object will have the exact same effect on the other entangled object at the exactly the same time no matter the distance between the two! Which means that the information is being communicated faster than the speed of light.
If he does this he has proven that something can travel faster than the speed of light - the communications between two quantum entangled objects.
Just because something travels faster than the speed of light does not mean that is time travel.
To conclude that communication travels back in time: An observer watching both two quantum entangled objects at an exactly the same distance from each would notice one of the quantum entangled change before the effect was done to the other one. To affect one quantum entangled object and see the effects occur on the second object at the exact same time would lead you to the conclusion that the information was transferred faster than the speed of light.
If he can accomplish this we will be able to have faster than light communications.
My Sig indicates the end of the comment I posted.
...see no point welcoming our backwards-in-time-travelling photonic Overlords. After all, they've been here all along.
"Whether or not you believe me, I'm right" -RWF
Warning: It was not just the coffee. When I didn't drink the coffee they poisoned my lunch in the fridge, with the same slow acting poison. Someone is trying to (and has) murdered me unless you don't eat your sandwich, either.
When you figure out what the hell is going on, send another message back in time.
Cordially, Future Lord Kano.
P.S. If there's not another message from you, assume the worse and don't go into work today.
If corporations are people, aren't stockholders guilty of slavery?
You know, this raises an interesting question (at least to me). If many people can see into the future, what would happen to stock valuations? Seems like the worst that would happen is stocks would move sooner on events than otherwise would, and speculation dies out.
I Browse at +4 Flamebait
Open Source Sysadmin
Not so very crackpot, though probably by accident - EVERY time-travel idea ever considered has the caveat of not being able to go back to before the machine was built.
So, in fact, what the lack of time-travellers demonstrates is the lack of any time-machines, either of the human-built kind or the appropriately-charged-black-hole kind.
What are they really trying to do?
They entangle two photons and measure the ones after the other? Won't the first measurement set the wavefunction to one of the eigenstates, and determine the other photon's state just as in "ordenary" entanglement. But wait, with relativity, the time-order of the two measurement effects is in some frames of (speed)reference the other way around, my guess the experiment has something to do with it.
Guess the article says too little, and the slashdot know to little for a proper discussion. My point is that there is more to it then meets the eye.
From the article..
"Adjusting the position of the detector that captures the second photon (the one sent through the cables) determines whether it is detected as a particle or a wave."
Ummm... I think the researcher is measuring the 'spin' of a photon, which can either be Up or Down. If you measure the photon as 'up' at the end of your cable, then you know the other photon was 'down', for example. The reporter is confused about Particle-Wave duality which doesn't have much to do with the experiment.
But you have *NOT* transferred any information into the past or into the future or over a distance. Yes it is true that you have discovered what the other photon must be, but you have no control over what the other photon will be. Somebody measuring the second photon would get no indication that the first photon had been measured.
So it is true that the person measuring photon 1 will know what answer the photon 2 person will get. But person one has no *control* over what person 2 will get.
From Wikipedia:
"Observations on entangled states naively appear to conflict with the property of Einsteinian relativity that information cannot be transferred faster than the speed of light. Although two entangled systems appear to interact across large spatial separations, no useful information can be transmitted in this way, so causality cannot be violated through entanglement. This is the statement of no communication theorem."
http://en.wikipedia.org/wiki/Quantum_entanglement
-Jenny
What stops the photon from chaning its state while it is traveling through the fiber optic cable?
I often have trouble remembering which way is out of bed in the morning.
apparently one of the mods has faced the dilemma of trying to choose which woman to date
Doesn't sound very likely to me. You must be... no... hold on. Oh.
Is the title somehow misleading? They are looking for effect before cause. This means they are looking for an indication of a future event, not sending a signal back in time. From their frame of reference, they are seeing the effect first, which is actually a prediction of a future event. Shortly after, the prediction comes true...
... now I have a great idea on how to choose tomorrow lotto numbers, talk to you all later!
Maybe the universe will vanish in a puff of logic!
WOW!
http://nathanlindsell.blogspot.com/
Complete with images that contain an Adobe Photoshop ID in their header...
.... he can get have the reply all keyed up and waiting ready for you when you ask.
Does that mean that once you receive information then you have to start the proccess all over again? So its not a perpetually on-state receiver but a one time event? Once manipulations/observations?? have been made to one member of the entangled pair can further manipulations still be made?
If changes are able to be constantly made it seems to me that values would only ever read one state, the one of the event the shortest distance into the future. It seems that all future events would have to converge at the single point of the present. In travelling from the future to the present, only the last manipulation would carry through.
Is either situation anywhere near the truth? It seems that either multiple machines would have to built (or multiple beams within a single machine) and set aside for sending information back from prescribed time intervals.
Any information you have, or a nudge in the direction of some good reading would be great. Thanks
It's actually "Jurisprudence fetishist gets off on technicality". Yours is still good, but not as funny.
OTOH, maybe coming back in time would bring a Flu strain that would wipe us all out?
this happened already on this continent. The Europeans got in great sailing vessels, went across the ocean, and traveled back in time to find a society 1,000 years older than their own...and promptly destroyed it with some nasty biological weapons.
+&x
If it worked, wouldn't you know that it worked before you did the experiment?
So, what *is* time?
Is it a 1-dimensional parameter - that can be reversed without breaking the laws of physics (with a positron being an electron moving backwards in time); or is it one of the 4 dimensions of the spacetime that, therefore, depends on the frame of reference; or, is it the growth of entropy?
Ahh yep, sorry, you're right - I shoulda looked on my bookshelf before posting ;) It was some time ago I read it; also read Bear's work so I confused the two. Thanks for the clarification. 'Manifold' sounds like a good story too, similar to Blish's(?) story 'Bleep' or something like that, in which a 'Dirac transmitter' has an annoying squawk on each message which after analysis turns out to be every message sent in the future, compressed.
Oh awesome, this is guy that came up with the Transactional Interpretation of Quantum Mechanics which is an alternative interpretative of quantum mechanics (and my personal favorite!) based on Wheeler-Feynman's absorber theory of Electrodynamics involving waves going both forward and backward in time (half-retarded, half-advanced, which he explains in his Lectures on Physics). Originally Cramer only proposed it as a teaching tool that gives the same answers as other interpretations, but I guess he's now trying to find experimental evidence that would actually distinguish it from the others.
o de2.html
The Transactional Interpretation makes *much* more sense than Copenhagen in my opinion (I still dig the Many Worlds interpretation though). Time symmetric theories like this also seem to the answer the question as to why there is an arrow of time. The laws of physics are completely time symmetric. For example, both "retarded" (those going forward in time) and "advanced" (going backward in time) waves are solutions for the electromagnetic wave equation, but the advanced ones are just "thrown out" for being unphysical because "obviously" you don't see waves converging onto an accelerating particle anymore than an egg will reassemble itself after being dropped, despite the fact neither is prohibited by the laws of physics. In these theories the direction of time is determined by the boundary conditions of the universe at it's beginning and end.
Feynman worked out the math in his absorber theory and found that if the universe where a "perfect future absorber" meaning all the waves sent into the future were cancelled all the advanced waves would be cancelled out except at the point of origin, so you never see them and the universe would have a defined arrow of time. In this theory when you push an electron it sends out waves which interact with every other particle in the universe that then send waves back in time to push on the electron at the exact instance you start pushing on it. In the transactional interpretation, there are these "offer" waves and "transactions" that work similary to entangle particles and give the "spooky action at a distance". In no case is information ever sent superluminarly (i.e. faster than light) or acausally. IMHO it also makes the universe appropriately "Machian" as well.
Check it out, very cool stuff:
http://www.npl.washington.edu/ti/
http://www.npl.washington.edu/npl/int_rep/dtime/n
RTFA, man.
They have a "special kind of crystal." Duh!
In Capitalist America, bank robs you!
The article doesn't say what kind of crystal, but I'm willing to bet it's calcium fluoride. This crystal is transparent to ultraviolet (which makes it a good candidate for EUV lithography in chip fabrication, a potentially useful technology in shrinking our fabrication process sizes), and it is birefringent. The researcher specifically mentioned using ultraviolet photons, so this made me think of calcium fluoride. The birefringent property would make it ideal for an experiment where you needed to split a UV beam to create entangled photon pairs.
And yes, I'm aware that birefringence also poses problems for using CaF2 as an optical material for EUV lithography. (I was working for a company that was developing novel techniques for growing these crystals with the crystalline lattice aligned in such a way that grinding a usable lens out of the material was much more practical.) For this experimental application, though, birefringence is actually an asset, not a liability.
600 comments and no Sarah Connor joke? Someone must have gone back and erased it, it's the only logical explanation.
Huh? Oh yeah, that.
We can give it to the Duke Nukem Forever developers in 2173 and have them send the beta back to us.
"if only it had worked, you could go back in time and tell yourself not to waste time on it" ;)
seriously though, could you imagine be able to perform an experiment in a way that you test something 10 times on exactly the same ingredients?
If many people can see into the future, what would happen to stock valuations?
I had thought of that too. It is another paradox. Stock price goes down because less people want to buy it, but if just 100 people knew (from the future) that the stock would go up in a week, then they would all try to buy lots of shares, which makes the stock go up prematurely, maybe as high as the original target price.
Even if 1 guy could do it, what would the IRS or anyone else who found out think that he turned $1000 into a $1 mil, and was NEVER wrong? All casinos would eventually bar him. And could he resist the temptation of "celebrity" from always being right? So he gets a TV show or slot predicting races, games, etc. but then everyone bets with him and few bet against, so the payouts are not very good. You would have to give 70 point spreads to tempt people to bet against.
So how long until he LIES about an outcome, just so he can bet against all the suckers and take all their money (ie: sell out). As you can see, this can go on and on in infinite ways, all of which are bad or change the actual outcomes. Or at the very least make a new TV series...
Tequila: It's not just for breakfast anymore!
Saturday's powerball numbers are 5 12 24 26 37 : 25. You can all wait till then to believe. If it sounds insane to give you these numbers, it is not. I will make enough off the stock market tomorrow to pay the lottery winners myself.
2*31*37*263
"Don't use the time machine!"
I want to express my support for nerdloving chicks and the geeks who fly long distances (preferably full fare economy or first refundable) to meet them. May I suggest you buy a delicious cookie ($2.00) and a whisky sour ($5.00) and a pillow ($1.00) to rest your head for the flight.
[-- Trust the Monkey --]
..the "twins paradox" for some reason. Too bad they can't measure the ages of the "entangled photons"... Or can they?
There is simply too much glass..
I am a physicist, specifically one who specializes in quantum information.
The write-up is total garbage. Sadly, I've read enough mangled pop-sci descriptions of quantum mechanics that I can translate most of it into non-gibberish--in true Slashdot fashion--without even reading the article (which is probably even more full of gibberish, and thus capable of rotting your brain). I did have to look at the article to figure out whether it's the journalist or the scientist that bears responsibility for this mess. Here's my translation:
The U of W physicists want to do a test of Bell's Theorem in such a way as to close one of the "loopholes" in previous tests (the possibility of signaling between particles).
Some background:
Bell's Theorem is at the heart of what makes quantum mechanics so shocking. If you want to understand one of the greatest accomplishments of modern science, you owe it to yourself to learn about the famous EPR criticism of quantum mechanics (Einstein, Podolsky and Rosen, Physical Review 47, 777), Bell's Theorem, and the Aspect experiment. The EPR elegantly lays out what so many people find weird and shocking about quantum mechanics (and what Einstein et al took to be evidence of its incompleteness), while Bell's Theorem and Aspect's experiment show that yes, the world really is this weird, and the EPR paper is wrong.
The link I've provided to the EPR paper will unfortunately only get you the abstract, unless you're at a university, in which case your institution almost certainly has a subscription to Physical Review. To learn about Bell's Theorem, try the appendix in "Introduction to Quantum Mechanics" by David Griffiths. AFAIK, the derivation of Bell's Inequality is only a few pages, and requires only basic calculus. The derivation is accessible to non-physicists who either know or are willing to learn basic calculus.
The above reading is not an easy project for a layman, but it is doable. It will give you a better understanding of modern physics than any number of "popular science"-type books you could read. Without the math, all that's left of quantum mechanics is people BSing about their favorite "interpretation". If you want to know enough to make up your own mind, learn about the EPR paper and Bell's Theorem.
The U of W experiment:
So, if Bell's Theorem has already been tested by Aspect, what's left for the U of W team? Bell's Theorem allows one to disprove all local hidden-variable theories. Aspect's original experiment didn't quite satisfy all the conditions for such a test, in that there were "loopholes" through which a very contrived theory with bizarre features might escape. Many people have since done experiments to close some of these loopholes.
Initially, just based on the Slashdot write-up, I thought the experiment was designed to close the locality loophole: if the two particles are not spacelike separated, a subluminal signal could in principle be sent from one to the other to tell it how to "respond" to a measurement. The way to close the loophole is to make sure the measurements of the two particles are spacelike separated events. This would be a reasonable experiment to do, although I think may already have been done.
Having read the abysmal Seattle PI article linked in the write-up, it looks like that's not what's planned. Cramer is the inventor of a somewhat less-popular interpretation of quantum mechanics, the transactional interpretation, in which particles send signals forward and backward in time. This isn't quite as crazy as it sounds, since there's time-reversal and other symmetries inherent in quantum mechanics, but I wouldn't call it well-accepted. What's more concerning
This is similar to echoing in sound. In sound the audio wave propagate through the air and then bounce of an solid surface and bounce back to you reasonably perfect. In this quantum is the propagation medium and the photons are entangled in medium for 50 milliseconds which is long time for photons.
Does this imply faster-than-light communication?
What if the signal arrives from the past and he gets so excited he doesn't press the button to make it happen in the past? Does the time line break everything?
Obama = Socialism.
Well given that Iraq is situated on what used to be Babylon, perhaps when Iraq is renamed we can start referring to the old America as the new Babylon.
Then a lot of those end-time biblical prophecies might have been fulfilled.
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
Wow, reading all of these comments makes me realize how little I know about Quantum Physics. I wish I read that book by that wheelchair guy.
Love many, trust a few, do harm to none.
It is NOT possible to send a signal back in time because, if there will EVER be a way to do that, why hasn't anyone ever received a signal from the future?? Unless the people in the future are going to be SO smart that they know better than to use their technology, knowing that they are going to alter the past by doing so and SCREW up the future. Or, maybe there IS a way to send signals back in time but our present (the past for them) was ALREADY altered because they attempted it and they caused the person who will invent sending signals back in time by more than 50ms to never be born in the first place!! Woah that really gets you thinking, eh??? OMG I just had de-ja-vu!!!
Paul
I just figured out by reading several websites and blogs (yeah, this has really been bugging me :-) what bit of information about the Bell state quantum eraser experiment is missing for those who think that it should be able to send information instantaneously (including myself, until just now!):
At each detector is a stream of photons, only a few of which, here and there, are part of an entangled pair. The determination of which photons are part of an entangled pair and which are not can only be done by performing a time-correlation of events at the two detectors.
Only the entangled photons exhibit the strange behavior, but the detector is registering all the photons. Therefore to know which "events" of photon detection to ignore and which to pay attention to (and thus observe the strange behavior), one has to first correlate the timing of the photons received at the two detectors. This is the necessary classical communication channel that others are talking about.
While this simple fact (the embedding of the entangled photons in a stream of otherwise unentangled and uncorrelated photons) might be obvious and elementary to those schooled in the field, it would help if it was actually stated that way explicitly in a few more places. Even now, it seems obvious to me (yeah, the parametric down-conversion occurs only sometimes), yet now that I see it, I can tell from so many other comments that this is exactly the aspect of the experiments that is not clear to people.
Okay, so let me take my questioning to the next logical step:
The parametric down-conversion results in two photons, each of which has one half the energy of the original photon from which the entangled pair was produced. Thus, each side of an entangled pair has a different frequency than the non-entangled photons emmanating from the crystal. Is there a way to filter out the higher-energy non-correlated photons without destroying the entanglement of the entangled pairs, thus letting only the entangled pairs continue on to the detectors?
One can immediately see where the question is leading: If there is, then wouldn't the interference pattern at the proximal detector be observable without correlating detection events with those at the distal detector?
--When you buy proprietary software, you don't get better software. What you get is the right to complain about it.
I'm the guy who just posted the parent post (saying there's no way to send a signal back in time.)
This is extremely important... Think about this... Consider the experiment the scientists are going to attempt using quantum physics to send a signal back in time by 50 ms. 50 ms is a very small period time...Now consider the scenario where they can send the signal back by 500 ms instead (which is a half second.) Assume the scientists create a device that had a button and a little light next to the button. When the button is pressed, a signal is sent back 500 ms. When the device picks up on a future signal (caused by a button-press), it will flash the little LED light once to show you it received the signal.
NOW this is the part where you are going to realize TIME TRAVEL OR SENDING SIGNALS BACK IN TIME CANNOT HAPPEN...
here goes... every time you go to press the button, a half second before you press it, the light comes on. What if the light came on but you decided "OH haha i'm not going to do it!" THEN WHAT?? So are you thinking the light would have never come on in the first place? That's a problem.. the light can never illuminate because every time it SHOULD illuminate, you always have the choice NOT TO PRESS THE BUTTON. If you think about it, you will realize that the light can never illuminate! It just can't... If it ever does, you can choose not to press the button.
OH and, by the way, if it is determined that a signal can only be sent 50ms back in time, that still implies that you can send a signal back by ANY amount of time because you can chain them together. You can have 10 seperate devices that each send a signal back in time by 50ms and when the each subsequent device gets the signal, it will, in turn, relay the message back by another 50ms. This would create a 500ms (half-second) relay backwards in time. 100 of these devices would achieve a 5-second communication backwards in time.
Paul
But what if you step onto a different time-line, then use that time-line to hop into your original timeline, but at an earlier point (and thusly travel back in your own time)?
I think I'm placing my money on the "ain't working" card, but it'd of course be interesting to be proven wrong...
In fact, we already have such behaviour in Windows - seen it just yesterday, when pinged one machine from another in the same LAN. The time was about -37ms, so that means some signals have to travel in time...
Traveling in time is something my team is doing every time we are approaching projects deadline.
Okay, I've been thinking about this some more, and I think I understand more fully what radtea was saying: It's not even all the entangled photons arriving at Ap that form the interference pattern (or, rather, that exhibit the strange behavior re: polarization detection). Rather, it's only the set of photons having one or the other polarization--in other words, each half the entangled pairs actually form the pattern (when detection is erased), but the order of arrival is random, so in order to see the pattern, you have to correlate with events at the other detector so you can look at only one half or the other. The "eraser," while erasing knowledge about the polarization of the photon (re: slit detection) also filters out half the photons.
Going back to the Bell state eraser, then (even though this is a long-dead thread, now), what if you inserted another polarizer after the "eraser", this one again oriented in such a way as to restore detectability of which slot the photons in the other stream went through. Now couldn't you, by inserting and removing this other polarizer un-erase and re-erase the Bell state so that the interference pattern correspondingly disappears and reappears?
What if there were a way to measure the passage of a photon without measuring or affecting it's polarization? If this were inserted just after the "eraser," wouldn't it give the necessary time correlation to know which events to look at at the proximal detector? Then, far down the line, if nothing were done to the distal beam, the pattern, when correlated with the
"passage detector," would show an interference pattern.
But that's the rub, isnt' it? There is no way to measure a photon's passage without affecting it in some way that either destroys entanglement or alters the photon's poarlization.
--When you buy proprietary software, you don't get better software. What you get is the right to complain about it.
No, it implies that we won't see the trick until after the trick has taken place. And the trick hasn't happened yet, so be patient.
So basically as soon as the scientist performs his voodoo witchery, he'll find a little message for him in his back left pocket. Which he would find there immediately after the trick, not before... ie Changing the past! If everything existed all at once, nothing would exist.
"Titor can't make it to the card game yesterday... he's gone home tomorrow ok"
So the movie it's like is not Back to the Future, but Contact (that rather ho-hum Jodie Foster/ Carl Sagan vehicle) where the aliens just send us a message and we build the machines. Suggests that time travel will be worthy but dull.
I can't remember where I read it, but someone once said that the best evidence that time travel into the past isn't possible is the sheer lack of tourists from the future.
Um, they've invented invisibility cloaks. They like to watch you masturbate from your window. That's what your dog is always barking at.
Didn't Ben Affleck do this? IIRC, there was a dire message in that movie: Ben Affleck can't act, even in the future...
There exists no way of exchanging information without making judgments. --Bene Gesserit Axiom
I mean that in the nicest possible way. None of you know the nature of reality. You are all out of your league.
Actually, it's "UNDER NO CIRCUMSTANCES GO TO P4C-970".
i have to talk like e e cummings because the lameness filter hates me
Please, for the good of Humanity, vote Obama.