Monday, August 26, 2013

Heretics in the church: black hole information loss

Bob Wald gave a nice talk from the "relativist perspective" at the KITP workshop on firewalls -- see Fri Aug 23 3 PM ; slides. (@36 min things heat up a bit :-)

One of the ideas that he and Bill Unruh have advocated over the years is that decoherence is an example of pure to mixed state evolution that doesn't require catastrophic side-effects like energy non-conservation (Banks, Peskin, Susskind; B-S interchange with Wald @42min :-). For related discussion, see these papers: BHs and spacetime topology, BHs and decoherence and this talk from an earlier KITP workshop by Bill Unruh.

Bob also takes some shots at the church of AdS/CFT, pointing out that the duality is not well-defined and still a conjecture. If AdS/CFT is the strongest argument in favor of purity of BH evaporation, then one should not abandon alternatives just yet ... (@53min some further discussion of this which unfortunately cuts off just as Maldacena is giving an interesting argument!)


Rastus Odinga-Odinga said...

Why would violating energy conservation be catastrophic? Energy conservation *has* to be violated when, as here, there is no timelike Killing vector. Everyone knows that energy is not conserved in cosmology for this reason, so what's the problem?

steve hsu said...

The B-P-S catastrophic energy non-conservation would local and ubiquitous... but I was never convinced by their paper (I'm with Wald and Unruh on this).

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