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Current Thoughts in String Theory
DrLudicrous writes "The NYTimes is running a nice little synopsis of the current ideas in string theory. Apparently, there is still quite a bit of disagreement about how to interpret the various theories, with some string theorists supporting a semi-deterministic worldview a la Einstein (God does not play dice), while others believe our universe is just one possibility among many, with respect to various physical parameters."
Still, intriguing stuff.
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In case the site is slow, or you don't have a stinking NYTIMES account, here is a mirror.
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This site is maintained by a professor and has a great book on string theory. http://www.mkaku.org/
Just use the StringTokenizer class, and leave the actual implementation to the virtual machine. That way, the best String theory can be used later, when it is derived, and you won't have to change a line of code.
(God does not play dice)
yep god is much more sophisticated, it's all decided through russian roulette.
You are correct in stating that we lack the energy to test string theory -- According to Hawking, one estimate of the (theoritcal) grand unification energy would be a thousand million million million GeV. Further, he goes on to say that it would take something the size of a solar system to produce this. So you're right, we can't do it.
BUT, there could very well be places that do have this necessary energy and could be observed to exhibit traits that we can measure and confirm theories with. This has been how most of the more recent unification theories have been confirmed -- either by measuring very small things with very fine equipment or measuring very large things in space.
To make laws that man cannot, and will not obey, serves to bring all law into contempt.
--E.C. Stanton
My housemate was recently developing a comprehensive theory of the oscillations of short bits of string, even comprising such philosophical points as whether they're inherent or caused by some bored unemployed minor god. Then I bought a laser pointer and now it's all refraction this and speckle that.
Cats are fickle.
While various Theories of Everything are being proposed, a lot of them are not based on observation. They are just complex mathematical magic created to explain reality. It's like someone saying the earth is suspended in space on the back of a big turtle which is suspended on the back of another turtle, ad. infinitum. For a human who doesn't have any means of verification, the turtle theory can explain things as well as gravity. Similarly, there are currently no means to verify string theory. It is about as good as the turtle theory until then.
Once quantum computing becomes a reality, would we be able to emulate some of the conditions certain experiments? I know an emulation is not the same as the real thing, but it would still be something,no?
..quantum physics probably doesn't exist...
From the article:The new calculations suggest that this dark energy cannot last forever, that it will disappear sometime in the far future
how can it disappear? does dark energy not follow the laws of conservation? (energy can neither be created, nor destroyed, only changed) any one have an answer?
Game Overdrive - Gaming News
I think that quote (or rather, truncuated paraphrases thereof) is much abused. What Einstein is saying (which is much clearer in a fuller context) is that while the probabalistic equations that comprise much of quantum theory are valuable as descriptive and predictive tools, they do much less to further Einstein's cherished ideals of really understanding the fundamental basis of physical reality. The statement "I am convinced that He does not throw dice" is a statement that while the equations of quantum mechanics might behave like statistics, they did not mean that the underlying reasons for why these equations work were simply artifacts of random, statistical processes - mere throwing of dice. Our ongoing failure to connect all the dots of the various paradigms could indicate that he was on to something...
It Is the Nature of Information to Transgress Artificial Boundaries
Strings are pretty cool. They make clothes (among other things), and when they vibrate, they make music. They're also good for fishing if you tie a hook at the end of it. String it up with two cans and you've got yourself a cool communication network!
I do have a theory on string cheese, though. I think it's a plot to tempt and destroy the lactose intolerant. So cheesy...so convenient...so stringy but oh so dangerous.
If particle man got in a fight with string man who would win? If he's underwater does he get wet or does the water get him instead? (They Might Be Giants)
Maybe god is like some kind of ubercoder, daring us to figure out his implementation.
And like most of them, he doesn't document.
~ Whence do you come, slayer of men, or where are you going, conqueror of space?
For anyone curious about string theory, I would highly recommend Brian Greene's "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory". He uses excellent writing style and plain, easy to follow examples to illustrate difficult concepts, and rather than going through lots of math and derivations, reserves that type of thing for the endnotes. It makes for a very approachable book that is particularly good for someone trying to learn new concepts rather than the struggle with the gory details of theoretical physics equations.
If Einstein's fudge factor is real after all, the universe will continue to expand faster and faster as space grows bigger and bigger, producing more and more repulsion.
Einstein's fudge factor is strikingly similar to Hershey's fudge factor, in which those unfortunate souls who are addicted to sugary goodness tend to expand faster and faster, producing more and more repulsion to members of the opposite sex.
So what happens when God messes up on bounds checking, or memory allocation for strings?
Segmentation fault. Asteroid dumped *shudder*.
I guess we're lucky He decided to steer clear of pointers.
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam
"...our universe is just one possibility among many, with respect to various physical parameters."
I'd like to think there's at least ONE universe out there where I'm skinny and good look'n!
"No pain, no... pain." Why don't we just leave it at that?
Any technology distinguishable from magic is insufficiently advanced. - Geek's corollary to Clarke's law
He hops up on a barstool and says "Bartender gimmee a bourbon on the rocks." The bartender says "We don't serve strings in this bar, git out!" So the string leaves, ties himself at one end and musses up the other. He walks back in and asks for a bourbon again. The bartender says, "Hey, aren't you that piece of string I just threw out of here?" And the pice of string says, "No, I'm a frayed knot."
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
It seems to me that all the desperate anti-anthropic people are frightened, at some deep existential level, by the undoubted, rational reality of there being no omnipotent Sky God watching over them. So ever-expanding universes, or universes where sudden phase changes in the structure of the dark energy destroy existing life, or universes with life-hostile substructural "laws" all make them feel too small, unloved, and insignificant against the vastness. Get used to it, we are cosmic dust. The simplest explanation is that there is no design, no Sky God, no plan, and no ordering. Sic transit gloria mundi.
Da Blog
Am I the only one drawn to the inescapable conclusion that God has deliberately obfuscated the universe to prevent reverse engineering? Or maybe I've just been working too hard...
"Freedom means freedom for everybody" -- Dick Cheney
Has anyone ever stopped to think that there is no TOE? And not just that, that there is no valid description of possible universes either? Theoretical physicists are playing mathematical games to find the TOE, but are having lots of trouble. The TOE should produce all the physical constants from its principles, right? What if the TOE has constants? Worse, what if someone proved a Godel or Turing like theorem that says something to the effect of "There is no theory that can describe everything, because there will be at least one (universe|force|particle|whatever) that does exist, but cannot be described." This is the most likely outcome I think.
At best I think that if we find a TOE it will have extremely poor predictive value because it will be so generic that it tells us not too much more about our universe than we already know, and simply give physicists new universes to wank around in. Not to say we shouldn't research this... ya never know where you might find useful stuff.
All long time readers of the rec.humor newgroups will recognize "the string joke". Apparently it was submitted so many times that it became a cliche for the "already heard joke", to the point that whenever somebody submitted what was thought to be an old joke, people would reply simply with the phrase "I'm afraid not". Ah, those were the good ol' days...
"Freedom means freedom for everybody" -- Dick Cheney
Two strings walk into a bar.
The first string says to the bartender, "Give me a beer." The bartender turns to the second string and says, "and what about for you?" To which the second string replies, "I would also like a beer#@a9101gb230b81;kajf3#$B89*#(&)*13!$%#@$" and goes on and on spewing gibberish.
The bartender, shocked, asks the first string, "What is your buddy's problem?"
The first string answers, "Oh, you'll have to excuse him, he isn't null terminated."
"You lied to me! There is a Swansea!"
His is just 20,000,000,000 sided instead of 20, and he gets +19,000,000,000 HP.
Pleasse, I cannot state this more emphatically, please DO NOT REGISTER with the NEW YORK TIMES. Under no circumstances should you use a THROWAWAY email address and provide FAKE information. They can track you, they will trace you, they will HACK into your computer.
If you have already registered with them, IMMEDIATELY disconnect your computer and BURN it. You must, absolutely must create a barrier between yourself and the NEW YORK TIMES made of TIN FOIL. Do not use aluminum foil, it WILL NOT WORK! Place this barrier DIRECTLY on your head and the heads of your PETS, otherwise you and your PETS will be HACKED.
Waste no more time! Do it now!
There are several overlooked points in the discussion. Someone above has already pointed out that the Einstein quote about divine gambling is over and misquoted.
String theory was proposed by Lord Kelvin, who started to investigate by developing a theory of knots, which was expanded by Reidmeister, and blossomed in the 20th century.
Einstein's special and general relativity were created to explain observed phenomenon that could not be explained by current theories. For special relativity, this was the constant velocity of the speed of light given by electromagnetism and confirmed by the Michaelson-Morley experiments. General relativity is a result of formulating Newtonian gravity in the field theoretic language used for unified electromagnetism. There were bits of data around indicating its necessity, though, such as errors in the perihelion of Mercury.
Quantum mechanics was similarly developed because of an incredible plethora of data. Thanks to Bell, we now know that (unless theory takes some really extreme turns), before an interaction with a "classical" apparatus, a quantum particle not only has unknown position and momentum, it actually doesn't have either. It's a subtle argument, but it's pretty well tested.
The motivation for string theory was to remove infinities in the fields which result from point-like particles. There is no physical motivation. String theory was not formulated as a theory of gravity or a grand unification theory. Those were bolted on afterwards as people noticed they could have sufficient degrees of freedom: you can build similar theories with straight up quantum field theory, and many people do for their life's work. So far the theory has produced one observable, which we already knew to far higher accuracy from quantum field theory. Pure number theorists get more physics as a by product than do string theorists. Supersymmetry and the Higgs boson are attempts to clean up mathematical holes, but they seem almost well motivated compared to the morass that is string theory.
String theory has driven a wedge between theorists and experimentalists in particle physics, and made it "unfashionable" to do serious theory that actually deals with reality. However, the popular press loves it: you can quote big sounding names and no one can nay-say them. Most areas of particle physics abjectly fail when it comes to explaining what you're doing to the layman.
Thankfully the pendulum seems to be swinging. At Caltech, their one phenomenologist has recently been absolutely swamped with pupils: string theory seems to be dying off at last.
And the point of QM is that such "relationships" fail miserably when subjected to small distances, energies, single particles, etc.
Random outcome of dice is just a concept to help us deal with extremely complicated situations.
Not necessarily. I'll assume you're not really familiar with all the implications of the uncertainty principle, but the problem is that it's actually impossible to gather the information required to make the predictions even if you had the correct parametric forms for all the phenomena. Case in point: what happens if I precisely determine the position and momentum of a particle (your die, if you will)? Well, for a very small particle, I have to use light with a very small wavelength to get sufficient accuracy with regard to position. Unfortunately, short wavelengt == very energetic, so that photon just knocked the crap out of our particle. I knew where it was before I disturbed the system, but I know knothing of it's momentum.
The concept here is that of conjugate (ie, non-simultaneously-knowable) variables. Position and momentum are a pair. Energy and time are another. Basically, the way to check is if the QM operators for two measurements are commutative. If they're not, you can't know the two properties to arbitrart precision.
So it's not just about computational power or inferior instruments. It's actually impossible to gain this information, no matter what.
-Looking for a job as a materials chemist or multivariat
Yes. A woman's thought process.
"Sorry, Adam. I didn't see that one coming either."
"Tolerance is the virtue of the man without convictions." -- G. K. Chesterton
Is there a click through license when you are born? And does a C-section circumvent it?
R: That voice. Where have I heard that voice before? B: In about 365 other episodes. But I don't know who it is either.
Some other good physics books that don't focus on String Theory that I also thought were very readable:
For Dark Matter and Dark Energy- Quintessence by Lawrence Krauss (who also wrote the Physics of Star Trek)
For Quantum Computing- Minds, Machines and the Multiverse by Julian Brown
The sending of this message pretty much inconveniences everyone involved.
But then Schrodinger's Cat started to play with it.
Now all I have is a mess.
III.IIVIVIXIIVIVIIIVVIIIIXVIIIXIIIIIIIIVIIIIVVIII
But Dr. Max Tegmark, a cosmologist at the University of Pennsylvania, said, "I think this grand dream is basically dying."
Along with BSD, trinity and internet.....
BSD has been dying for over 10 years.
Trinity died even before reloaded could hit the screen.
Internet has been dying for sometime now.
Yes I do have a physics PhD and I have done a lot of quantum mechanics in my time (low energy electron-molecule collisions). Yet, I don't have a clue about the string theory. Popular articles on the subject do not help at all (at least for me).
I guess this is just an extreme example of the typical slashdot discussion. A lot of people are "insightful" and "informative" particularly if the topic is esoteric enough.
Now all we have to do is find a way into the 2 dimensional universe!
It's called "Super Mario World"
It is easier to build strong children than to repair broken men. -Frederick Douglass
The universe is tied up in knots. Figuring out just how has physicists tied up in knots
QED
Free Software: Like love, it grows best when given away.
http://www.sciam.com/article.cfm?articleID=000F1ED D-B48A-1E90-8EA5809EC5880000
I know more about string and particle theory than 99% of the population, which means I'm still a comparative dumbass on the subject in relation to people who really know what they're talking about.
However, here's a spiffy chart of the current "standard model" to help people get up to speed. Especially helpful for those who don't normally deal with Mesons and Antibayrons on a regular basis...
Lawrence Person (lawrencepersonh@gmailh.com (remove all "h"s to mail)
http://www.lawrenceperson.com/
The NY Times article mentions that Nova is doing an string theory episode this fall (Oct 28,2003 and Nov 4, 2003) based on Brian Greene's book The Elegant Universe. Turns out the homepage for this episode is already online with plenty of interviews and animations.
He's referring to: The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory by Brian Greene.
You may also be interested in reading about loop quantum gravity, an alternative theory of everything. I' not expert, better refer to this reference that I looked up.
The New York Times had an article, way back in the day, on the New York transit system. It was in a shambles. A major fix to the system was implemented on a Monday. Can you see where this is going? Yup, the headline read "Sick Transit's Glorious Monday."
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
"Before" the Big Bang, we don't know. In fact, the phrase "before" the Big Bang isn't really well defined, since as best we understand the working of things right now, there is no "time" at all prior to the Big Bang, since time is a property of (and temporal dimension of) our Universe. So in what stuff, place or location did the Big Bang occur? Why was all that matter compressed into one point? Was it caused by some irregularity in some higher order somethingness? Did the Universe have to come into existence, or not? Did it have to take a certain form or not? Some of these questions are properly the domain of philosophy at this point, but all of them are questions that physicists would love to be able to analyze, if there were any data available. Unfortunately, barring radical new discoveries, we're just not likely to answer most of those questions anytime soon. But that certainly doesn't mean that physics is bollocks - you just have to understand that most of modern physics seeks to describe and model predictable behaviors of the universe, rather than to explain them. If you want answers to "how", physics is pretty good at giving them. If you want answers to "why", physics sucks - every "why" just produces another question that you need to ask "why to.
For example, I can say an electric generator works because of the electromagnetic force, and that the electromagnetic force produces an r^2 force between particles with a property we call charge. Why? Well, particles with charge exchange virtual photons which results in this force. Why? Err... well... because QED says so? It all breaks down after a while. Four years as a physics major led me to a deep, deep depression when I realized physics just couldn't provide the kind of Einsteinian "why" answers I was looking for. The great physicists of the first half of this century came into a rapidly growing field where it was reasonable to think we'd have it all solved soon. I came into a sluggish, sick field filled with unsatisfied, unhappy scientists. Ugh. Glad I got myself out of there. Rant off.