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Thursday, February 10, 2011

Through the wormhole

Tomorrow a team from the Science Channel show Through the Wormhole (Morgan Freeman is the narrator) is flying up to Berkeley to interview me for an upcoming episode. They found me because of a paper I wrote with my former postdoc Roman Buniy (see below). Roman is a brilliant guy who twice placed first in the Ukrainian physics Olympiad. He made the beautiful figures below.

Doing this kind of show isn't exactly a win-win: I would guess the volume of crackpot mail I receive could go up by an order of magnitude :-(

Semi-classical wormholes and time machines are unstable


Abstract: We show that Lorentzian (traversable) wormholes and time machines with semi-classical spacetimes are unstable due to their violation of the null energy condition (NEC). Semi-classicality of the energy-momentum tensor in a given quantum state (required for semi-classicality of the spacetime) implies localization of its wavefunction in phase space, leading to evolution according to the classical equations of motion. Previous results related to violation of the NEC then require that the configuration is unstable to small perturbations.

Here are some slides on the subject. Click for larger version. For more background on why it is difficult to construct effective field theories which lead to (stable) violation of the null energy condition (NEC), see Phys. Rev. D 74, 063518 (2006).

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