tag:blogger.com,1999:blog-8666091.post110263419537575787..comments2017-12-03T12:20:32.082+01:00Comments on The Reference Frame: Causality in SFT - Ted ErlerLuboš Motlhttp://www.blogger.com/profile/17487263983247488359noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-8666091.post-1102685920439592972004-12-10T14:38:00.000+01:002004-12-10T14:38:00.000+01:00Hi Lubos!
Thank you for your positive review of my...Hi Lubos!<br />Thank you for your positive review of my talk!<br /><br />I wanted to make a couple of comments about information loss... As you know, we found a local time coordinate for open string field theory along a single null direction. You can of course use this coordinate to quantize the theory canonically. This means a couple of things, at least naively: first, closed strings must come out of the theory in some way. Second, that time evolution is manifestly unitary, generated by a Hermitian Hamiltonian. Thus you might expect that the quantum formulation of OSFT would be relevant for black holes, and moreover information would not be lost since time evolution is unitary. Of course, seeing closed string physics in any quantum formulation of OSFT (including my operator formalism) is a unsolved puzzle---especially off-shell, as would seem to be required to describe such a nontrivial closed string background. Even if we were to believe that a black hole is decribed as some physical state |\Psi> in the open string Hilbert space, it is not at all clear what time evolution through x^+---a time coordinate describing evolution in flat space---means in the context of a black hole spacetime!<br /><br />I also wanted to emphasize that there is a real obstruction to describing open string theory (and closed strings too, presumably) in a completely local way. I would definitly not rule out, based on my work with David, that string theory could be nonlocal enough to realize black hole complementarity and avoid information loss. However, what we were trying to argue is that a local description of string theory can at least be "approached" in a (very singular) limit, which might explain the apparent "causality" of string theory in less violent situations, such as scattering experiments. Maybe David has a different perspective, but I believe nonlocality (at least in space) is a crucial aspect of string theory, and I think our work supports this view.<br /><br />All the best,<br />TedAnonymousnoreply@blogger.com