Slashdot Mirror
Stop, Light.
parvati writes: "The New York Times is reporting that two separate research teams, both from Cambridge, MA, have managed to slow, stop, and then reconstitute light. The ability to stop and then accurately restore a beam of light has implications for quantum computing and communication in that it may provide a mechanism to store the information coded by single photons."
Intensity is just the number of photons as percieved by your eyes. More intensity means more photos hitting your receptors. So, if the photons are conserved, just stopped and then restarted and redirected in the same direction, it would be percieved as the same intensity. You do have to ask if the number of photons is modified and/or increased by the slow down/stop/speed up process.
Except that relativistic velocities are not simply additive... v_net != v_1 + v_2. Rather, v_net = (v_1 + v_2) / (1 + v_1*v_2/c^2). That way, even if v_1 = v_2 = c, the equation becomes v_net = (c + c) / (1 + c*c/c^2) = 2c/2 = c. At speeds that are not a significant fraction of c, the equation gives v_net \approx v_1 + v_2, as the denominator is approximately 1 (well, 1 + epsilon, which as we all know, is 1).
Your flaw is trying to add things with dissimilar units... when you consider time as a fourth dimension, you are really doing calculations with ct (a length), not t (a time). That way, you can express the distance through spacetime as ds^2 = (ct)^2 - r^2 (or r^2 - (ct)^2, depending on which metric you use).
Eric
Eric
Would it be possible to create a huge bose-einstein condensate, break it in half and flatten it out?
If so, then you would merely need to transport the two 'gateways' whereever you wanted and teleport between the two locations.
The theory being that when you walk into one of the portals, your entire quantum makeup would be absorbed and transmitted to the other portal because of quantum entanglement.
Anyone think this would work? How would you stimulate the portal to 'release' your energy?/ declaration.html
http://www.nara.gov/exhall/charters/declaration
http://www.nara.gov/exhall/charters/declaration/d
http://www.nara.gov/exhall/char
Think about a football field that is 100 meters from end to end. Now think of a guy that runs in a straight line from one end to the other, along the sidelines. If he runs 10 meters per second, it takes him 10 seconds to run the entire length of the field. Now make the guy run from one corner to the other. He still runs at 10 meters per second, but it will take him more than 10 seconds to reach the other end. By spending some of his motion in the width-direction of the field, his motion in the direction of the length of the field becomes slower.
Think for a moment that time works just like a spatial dimension. You have a specific absolute speed in a specific direction.. time. When you start moving to some spatial dimension (one of the three traditional ones), your motion in the direction of time becomes slower because you are no longer fully "commited" in that direction.
Now think about photons. They move with ALL of their speed in some spatial dimension. Does this mean that photons stand still in time? If you slow down light, does this mean that time actually starts ticking for them? Could it be that the fading of the light has something to do with the fact that time runs for them? If they are in an absolute vacuum, light doesn't fade because time stands still, no matter how far you shine the light. Introduce "dust" and it slows down and fades.
I'm sure my theory is very flawed but I'm not exactly sure at what point. I mean time DOES slow down when you move, but am I looking at this the wrong way?
I wonder if this could also be used for holography
:) At first glance, I can concieve of doing with this as people have hypothized about quantum computers.. Send encryption keys that can only be read once down a fiber line, etc. The stumbling block I see here is that only the gas medium holds this property.. Transmittion down the fiber is still subject to existing hackability. But perhaps a short-distance "secure" channel of gas could be used?
:)
Better yet, it could be used for read-once messages. Albeit bulky and not as cool as flash-paper, or exploding sun-glasses.
Maybe not..
-Michael
-Michael
But uhh yeah, like has been said, velocity is a measure involving time. My stupid way of thinking is velocity measures the change of everything else, xyz, in fixed positions of time. So would moving in time measure (eg) zyt, in fixed positions of x?
I recommend "the elegent universe" by Tom Green. He very beautifully discrbes Einsteins relativity and multi-dimentionality in lay-terms and with lots of colorful analogies.
Essentially time can be thought of as the interval of a regular periodic event (such as a frictionless bouncing ball or pendulum.. or even a photon bouncing between two mirrors). The trick is that the event is periodic with respect to a single frame of reference. A man on a space-ship flying past you will observe a seperate period in your time-piece.
Light has a fixed velocity and is timeless in free space because it has almost no mass (there's still debate about whether it's truely massless) and thus can not "Do anything" that would be measurable (such as the position of a ball reflecting light to the observer). As the author suggested, by traveling diagonally across the foot-ball field, you're traveling in two dimensions. The hypotenus is the traveled path, and the sine or cosine is the observed path and velocity from either the point of view of time or any of the spacial dimentions. Its simple geometry.
However, when the light's wavefront interacts with neighboring atoms, they are achieving some sort of event that is non-instantaneous.. If they pass into an electron's event horizon and contribute to it's energy, that takes time. Likewise when they radiate out of the electron and continue along some new path (scattering), or reconstitute their original form (transparency).
There is massive speculation that the wave-nature of light (and all material for that matter) is such that the photon really travels all possible directions and interacts with all material proportionately (evidenced by single-photon refraction patterns). Thus the more matter nearby, the more interaction, thus the more timeable events, thus the more traveling through time, thus the less traveling through space, thus the slower apparent probagation of light through a non-vacume.
The "stop-light" above quite possibly is such a time machine for light where it travels sole-ly through time (or any of the other hypothesized micro-dimensions) until it's released. There is nothing totally radical about this, since this happens whenever a fermion captures a photon for an extended duration. The bizzarness is in the exact replication later on.
-Michael
-Michael
Even an electron has an event horizon, when the radius is small enough.. I believe that how they capture photons in the first place. Isamov's black-body radiation probably explains how the photons escape.
Light travels at different speeds in different mediums (due to permiability and permittivity values), so in a very slow probagation medium, it's possible that quntum particles get a boost in the sizes of their event horizons.
Of course this has little to do with the capture of other _atoms_ which is what initiates the common concept of a massive black hole.
It might be possible to pack so much energy into a quark that it's event horizon could capture another fermion. But of course it would be so "hot" that it would break through just about anything.
In theory, you could boost a particle with enough photons simultaneously that it becomes another particle (along the lines of string theory). It's the same basic idea of atom-smashers. If you were to find a big enough quantum particle, then it would have rest energy sufficient to maintain a suitible event-horizon withtout being too hot. Unfortunately the only way we currently know to give a particle enough energy is through larger and more expensive colliders.
Perhaps a focused "stop-light" could provide enough simultaneous photonic energy that the target quantum particles will rematerialize into something larger just long enough to collect neighboring particles in a mini-black hole.. Don't worry though, the most likely result will be a decay of that macro-particle in short order.
Quantum physics doesn't lend much room for ultra-massive particles. BUT, string theory suggests that all particles are inherently massive (a plank-mass - the wieght of a grain of salt) and that through vibration of 11 different dimentions their apparent mass is reduced in several discrete levels.
My idea is this. Take a massive spherical chamber filled with high a temperature gas that will act as this light-trajectory-storage medium. Shine bright light radially inward with the "store" light turned on... The light at the center will be dimmed and ultimately too low an intensity to wreck havoc. Then after sufficient time and energy is stored in this huge volume of now super-highly energetic particles. Trigger the light's release. Since the wave-front is stored, it should reproduce the original direction of the light and thus flash the center with energies approaching if not exceeding atom-smashers.
The high temperature gas will help obsorbe any reactions that might occur since their expansion should be minimized.
-Michael
-Michael
Obligatory no log in link
However, I wonder if this could also be used for holography: freeze the interference pattern into the material, and read it out later, reconstructing the image. In theory, since the material could record the interference pattern in three dimensions rather than two (like a photographic plate), this might allow for more detailed holograms.
www.eFax.com are spammers
That is the key concept that is poorly conveyed within the Times article. It's obvious that even good science reporting is not necessarily understandable by the masses without the teaching genius of a Sagan or the like.
This brings up an interesting topic, the subject of many late-night, coffee-fueled debates around here: If you could teleport a human through some means, would this property of "no-unique-identity" actually allow you to create an EXACT COPY of the teleported human (who is unaware that he/she/it is even a copy), while, in fact, you KILLED the original? How would you detect this?
What'dya mean there's no BLINK tag!?
I believe you forgot an 0 there! Login : slashdot2000 pass : slashdot2000 Worked for me!
Yes, you're right. Just found the Discover article, which does indeed say that the lab-grown black holes wouldn't be the real thing. They would instead be "a small and completely safe vortex of cold atoms" that would let researchers study the effects of black holes.
I've heard that this capability might allow scientists to create artificial black holes. Apparently if you can slow light down enough, you might be able to create a situation in which a singularity comes into existence. I wish I had more information on this-- I think I read it in Discover a few months back. I have no idea if this discovery would make such a thing possible. Anyone with more information? I'm obviously fairly ignorant in this area, but the article I read seemed to take the possibility seriously enough.
In order to reproduce your inner-most quantum states (e.g. the electrical synapses currently coursing through your system), you'd have to flash every particle some-how. Whenever you detect a particle, you disturb it significantly.
It seems to me that the only way you could teleport would be to 'flash' the host, then radiate their profile. It _might_ be possible to analyze the profile so as to reproduce multiple targets. But my belief is that the discretization of this profile information would render it useless. Additionally, analog amps / splitters could quite possibly introduce disturbences which would defore the target.
I still don't think teleportation will ever be practical for life-forms, but it might work for the simple transport of raw minerals (with pure substances). Perhaps, for example, you could energize the minned metal on the moon into a super-plasmic or photonic state which could be tunnelled. Alternatively the wave-properties in cooled matter might be of more use - Instead of super-heating, perhaps super-cooling is what is necessary. Course in either manner, the atomic structure is disrupted, so the usefulness is minimized.
Heck it would be useful just to condence matter to alleviate gravitational weight for greater space-transport.
Oh well, fun to brain-storm.
-Michael
-Michael
From reading the article, it sounds to me like the light is being destroyed and then new *nearly* (from the article it says it's not the same) identical light is emitted. While interesting, this phenomena is no where near as much of a breakthrough as if they had actually stopped light.
:)
Correct me if I am wrong, but are they not, in essense, just taking a snapshot of a photon and then recreating it?
I would go in to some of the implications of actually stopping light (instantaneous communications, etc), but it is too early in the morning for my mind to work that deeply
Technically, taking a quantum snapshot of a photon and then recreating it is the same thing as stopping it and restarting it. When we get down to such a level, we sacrifice the idea that a particle has an individual identity, and instead only acknowledge the existence of a set of properties for the particle. If the experiment simply resulted in light of the same frequency being emitted, then this would still be interesting as a means of optical storage, but by no means would it be as interesting from a theoretical perspective. What makes it interesting is that the imprint of the light is stored in the quantum spin states of the gas atoms, which means there is a theoretical possibility (which can't be determined too well from a nytimes article) that all the "uncertainty information" inherent in the photon is preserved across the restart. That would make this a true stopping and restarting of a photon.