Minkowski vacua can be metastable

TL;DR

The paper challenges the idea that Minkowski vacua are either absolutely stable or have infinite decay rates by analyzing vacuum decay and pair production, showing that the supposed divergence is not physically relevant.

Contribution

It demonstrates that the boost integration leading to divergence in vacuum decay calculations is unnecessary, and the quantum state remains Lorentz invariant, refuting the claim of catastrophic instability.

Findings

No catastrophic vacuum instability in a constant electric field.

Boost integration divergence is an artifact, not a physical effect.

Vacuum quantum states are Lorentz invariant.

Abstract

We investigate the recent suggestion that a Minkowski vacuum is either absolutely stable, or it has a divergent decay rate and thus fails to have a locally Minkowski description. The divergence comes from boost integration over momenta of the vacuum bubbles. We point out that a prototypical example of false-vacuum decay is pair production in a uniform electric field, so if the argument leading to the divergence is correct, it should apply to this case as well. We provide evidence that no catastrophic vacuum instability occurs in a constant electric field, indicating that the argument cannot be right. Instead, we argue that the boost integration that leads to the divergence is unnecessary: when all possible fluctuations of the vacuum bubble are included, the quantum state of the bubble is invariant under Lorentz boosts.