Superluminal Travel Made Possible (in two dimensions)

Understand

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.