Renormalisation Group Flow and Kaon Condensation

TL;DR

This paper uses the functional renormalisation group method to study kaon condensation, revealing a phase transition to a symmetry-broken phase with a condensate sensitive to scattering length.

Contribution

It introduces a set of approximate flow equations for kaon interactions at finite chemical potential and analyzes the phase transition using the renormalisation group approach.

Findings

Identifies a phase transition to kaon condensation at a critical scale.

Shows the condensate value depends strongly on kaon-kaon scattering length.

Demonstrates the applicability of the functional renormalisation group to mesonic systems.

Abstract

Functional renormalisation group approach is applied to a system of kaons with finite chemical potential. A set of approximate flow equations for the effective couplings is derived and solved. At high scale the system is found to be at the normal phase whereas at some critical value of the running scale it undergoes the phase transition (PT) to the phase with a spontaneously broken symmetry with the kaon condensate as an order parameter. The value of the condensate turns out to be quite sensitive to the kaon-kaon scattering length.