The Boring Monopole

TL;DR

This paper investigates how magnetic monopoles can catalyze false vacuum decay with reduced symmetry, using a new numerical method, revealing monopoles' potential to dominate decay processes and influence cosmological signals.

Contribution

Introduces a novel algorithm based on the mountain pass theorem to compute monopole-catalyzed decay with reduced symmetry, extending decay rate calculations beyond traditional assumptions.

Findings

Monopole-catalyzed decay can surpass homogeneous decay rates.

Reduced symmetry decay solutions are numerically accessible with the new method.

Monopoles may determine the Standard Model vacuum's lifetime.

Abstract

We study false vacuum decays catalysed by magnetic monopoles which act as tunnelling sites with exponentially enhanced decay rates. The field profiles describing the decay do not have the typically assumed $O(3)/O(4)$ symmetry, thus requiring an extension of the usual decay rate calculation. To numerically determine the saddle point solutions which describe the tunnelling process we use a new algorithm based on the mountain pass theorem. This method can be applied more widely to phase transitions with reduced symmetry, such as decays away from the zero and infinite temperature limits. Our results show that monopole-catalysed tunnelling can dominate over the homogeneous false vacuum decay for a wide range of parameters, significantly modify the gravitational wave signal or trigger phase transitions which would otherwise never complete. A single boring monopole in our Hubble patch may determine the lifetime of the Standard Model vacuum.