Wednesday, August 1, 2012

Entangled Particles Break Classical Law of Thermodynamics, Say Physicists

Entangled Particles Break Classical Law of Thermodynamics, Say Physicists:  A couple of years ago, we looked at an experimental version of Maxwell's demon, in which Japanese physicists created a kind of staircase in which they lowered an energy barrier to allow atoms to jump up a step and then raised it to prevent the atom falling back down again...

However, what was extraordinary about the Japanese experiment is that it converted information into energy...

Imagine two boxes of particles with trap door between them. You want to use the trap door to guide the faster particles into one box and the slower particles into the other. In a classical experiment you would have to measure the particles in both boxes to do this experiment.

But things are different if the particles in one box are entangled with the particles in the other. In that case, measurements on the particles in one box give you info about both sets of particles.

In essence, you're getting information for nothing. And since you can convert that information into energy, there is clear advantage when entanglement plays a role.

That's hugely significant. It means that the laws of thermodynamics depend not only on classical phenomenon and information but on quantum effects  too. The breakthrough that Funo and co make is to extend the theory to take this into account. "We show that entangled states can be used to extract thermodynamic work beyond classical correlation," they say.

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