Do not mess with time: Probing faster than light travel and chronology protection with superluminal warp drives

TL;DR

This paper investigates whether quantum effects can prevent faster-than-light warp drives from enabling time travel, proposing a mechanism that destabilizes such solutions in both standard and Lorentz-violating quantum theories.

Contribution

It introduces a pre-emptive chronology protection mechanism that destabilizes superluminal warp drives through quantum back-reaction effects, preventing their use as time machines.

Findings

Quantum back-reaction destabilizes warp drives.

Chronology protection applies in both standard and Lorentz-violating quantum theories.

Warp drives cannot be used for time travel due to quantum effects.

Abstract

While General Relativity ranks undoubtedly among the best physics theories ever developed, it is also among those with the most striking implications. In particular, General Relativity admits solutions which allow faster than light motion and consequently time travel. Here we shall consider a "pre-emptive" chronology protection mechanism that destabilises superluminal warp drives via quantum matter back-reaction and hence forbids even the conceptual possibility to use these solutions for building a time machine. This result will be considered both in standard quantum field theory in curved spacetime as well as in the case of a quantum field theory with Lorentz invariance breakdown at high energies. Some lessons and future perspectives will be finally discuss.