Superluminal travel in two dimensions

Speaker: Sergei Dubovsky, Stanford University

When: March 30, 2009 (Mon), 12:30PM to 01:30PM (add to my calendar)

This event is part of the HET Seminar Series.

Abstract:
“We argue that superluminal signal propagation is possible in consistent Poincare invariant quantum field theories in two space-time dimensions, provided spatial parity is broken. This happens due to existence of the instantaneous’‘ causal structure, with one of the light cone variables being a global time. In two dimensions this causal structure is invariant under the Poincare group if one gives up the spatial parity. As a non-trivial example of a consistent interacting quantum field theory with this causal structure we discuss a non-linear SO(1,1) sigma-model, where SO(1,1) is the Lorentz symmetry. We show that this theory is asymptotically free and argue that this model is also well defined non-perturbatively, at least for some values of parameters. It provides an example of a microscopic Poincare invariant quantum field theory with local action, but non-local physical properties. Being coupled to gravity thisinstantaneous’‘ theory mixes with the Liouville field. If proves to be consistent, the resulting model can be used to construct (non-critical) string theories with very unconventional properties by introducing the instantaneous causal structure on the world-sheet.”