Warped space-time for phonons moving in a perfect nonrelativistic fluid

TL;DR

This paper introduces a theoretical model of super-phononic travel in nonrelativistic fluids, creating an analogue of warped space-times that allows for faster-than-phonon propagation without violating energy conditions.

Contribution

It constructs a kinematical analogue of superluminal travel using effective space-times in perfect fluids, avoiding violations of energy positivity and not relying on Einstein's equations.

Findings

Demonstrates super-phononic travel in fluid analogues

Shows effective curved space-times can be engineered with obstacles

No energy condition violations are required

Abstract

We construct a kinematical analogue of superluminal travel in the ``warped'' space-times curved by gravitation, in the form of ``super-phononic'' travel in the effective space-times of perfect nonrelativistic fluids. These warp-field space-times are most easily generated by considering a solid object that is placed as an obstruction in an otherwise uniform flow. No violation of any condition on the positivity of energy is necessary, because the effective curved space-times for the phonons are ruled by the Euler and continuity equations, and not by the Einstein field equations.