This enables information to escape black holes while also respecting quantum mechanics

Mar 6, 2013 15:21 GMT  ·  By

The so-called black hole "firewall paradox" created plenty of waves among physicists last year. The paradox claimed that only two of three major principles of physics could be true at the same time in the case of a black hole.

Despite the idea being so radical, which usually means it's wrong, physicists weren't able to solve the problem as quickly as they had hoped.

Now, physicists at the University of York have proposed a solution to the firewall paradox, which uses quantum information theory, a relatively modern branch of quantum mechanics. Their solution is published in a paper in the Physical Review Letters.

"We are the first to show the necessity of entanglement across all black hole event horizons and to consider what happens as black holes age," Professor Sam Braunstein, one of the two physicists that authored the paper, said.

"The greater the entanglement, the later the curtain descends. But if the entanglement is maximal, the firewall never occurs. Indeed, entanglement has long been believed to exist for some types of black holes, taking on exactly this maximum value. Our work confirms and generalizes this claim," he added.

The problem with the firewall paradox is that a particle can't be entangled with two other particles in the same way at the same time. But it would have to be for information to escape a black hole.

So, either information can't escape a black hole, something most physicists today don't believe is true, or the laws of physics break down. You'll find a much more detailed explanation of the firewall paradox here.

The new paper seems to solve the problem by saying that, while information does leak out of black holes, it does so at a late stage in a black hole's life, so that three particles are never entangled at the same time.

"We show that, in order to preserve the equivalence principle until late times in unitarily evaporating black holes, the thermodynamic entropy of a black hole must be primarily entropy of entanglement across the event horizon," the paper's abstract explains.

"For such black holes, we show that the information entering a black hole becomes encoded in correlations within a tripartite quantum state, the quantum analogue of a one-time pad, and is only decoded into the outgoing radiation very late in the evaporation," it adds.

"This behavior generically describes the unitary evaporation of highly entangled black holes and requires no specially designed evolution. Our work suggests the existence of a matter-field sum rule for any fundamental theory," it concludes.