How is this possible? Faster than the speed of light?

Question

http://physicsweb.org/articles/news/4/7/8

Can someone explain this?

Answer 1

Superluminal experiments have been around and controversal for some number of years now, taking advantage of the fact phase velocities in quantum theory actually normally travel faster than the speed of light (de Broglie waves) for mass particles, or photons in other than vacuum medium. The quantum treatment of the photon uses a position state function which is a superposition of a spread of de Broglie waves, normally a Gaussian spread, resulting in a Gaussian envelope travelling at what's called a "group" speed. This group speed normally travels at the speed of light in a vaccum.

With non-linear optics, physicists can manipulate the phase speeds as to produce a "group wave" that actually travels faster than the speed of light. The controversy is over whether or not this could successfully be used to transmit real information, instead of quantum information. In other words, many physicists aren't quite convinced yet that these superluminal "group waves" aren't nothing more than pseudo-group waves. The jury hasn't returned to the courtroom.

The theory of relativity only POSITED a finite speed of light. Moreover, it originally didn't even address the quantum nature of light, although many quantum theories now incorporate relativistic formulations. Conventional quantum theory itself also presumes a finite speed of light, but it does not actually prove it either. In both cases, the finite speed of light, at the end of the day, is only of empirical basis, not theoretical. It leaves open the possibility of "bending the rules" to achieve superluminal speeds, but it's still quite difficult to bend them. However, there are many physicists who would love to seem them simply smashed.

Answer 2

They are talking about speed of light in respect to mass.
Mass in this case is:

m = m' / sqrt(1 - v^2/c^2)

Where;
m' = mass of object relative to you
v = velocity
c = speed of light

you can see as v approaches c, the denominator goes to 0, which means m goes to infinity.

A real example of faster than the speed of light is shown in paired particles. These pairs have 'spin' which stays opposite each other. At any time you observe them they will always be opposite. A group of scientists in Chicago decided to do this experiment. They separated the 2 particles - 1 stayed in Chicago - the other went to Minnesota. It was proven that the 2 particles still had opposite spins at any given time. That means the 'communication' between these particles is instantaneous (which is faster than the speed of light). Experiments have taken place to try and isolate the mechanics of what happens but fail. If we could figure out how it works, we would be able to tell the future.

Answer 3

ok let me just start by telling you that there is a theory that says that as an object aproaches the speed of light its mass increases to almost the equivalent of mass of the universe so the only way something can move that fast in through a wormhole or blackhole so at the end of a black hole there is a "white hole" and in order to get through it you must be as small as a single atom and the power of one of these black holes is so great even light cannot escape,( and light is noting more that waves that travel trough the form of radiation so), that means it is faster than the speed of light its a simple concept yet very complicated if you want to find out more you should check out einstein's theory of relativity and some of his othe equations.....really u can learn a lot o stuff

Answer 4

fact of the matter is, this happens all the time when you compare relativity theory with quantum mechanics... seperately the two theories have been shown to hold up under even the most scrutinizing experiments... Scientists have been able to predict the outcomes of these experiments incredibly accurately a staggering number of times.

These two theories are the staples of modern physics and technological progression

However put them together and it becomes apparent that they both can't be right. They contradict one another at every fundamental level.

the question your really asking friend is the pivotal question in modern physics, and no matter how clever sounding the answers you get here are, The best answer your gonna get is this... Nobody really knows :)

Answer 5

The article is mostly self-explanatory. The key point is that although interesting games have been played with the phase velocity, the speed at which information can be transferred (which is related to the group velocity) is still limited to the speed of light.

Answer 6

First, you have to understand that the maximum speed possible is only theorised.
The experiment suggests otherwise, and you must allow for relativity. It's like if you walk, at 10kph, to the front of a bus that is moving at 60kph, theoretically you are moving at 70kph, but we know that, in fact, that is not possible.
This is not an exact analogy, but the scientists sent a laser beam through a cell with a rapidly moving wave-length, thus making it appear to move faster.