Post-Inflationary Quenched Production of Axion SU(2) Dark Matter

TL;DR

This paper models the post-inflationary production of axion SU(2) dark matter as a quantum quench, refining the understanding of its relic abundance and providing analytic and numerical insights into its dynamics.

Contribution

It introduces a dynamical quantum quench framework for axion SU(2) dark matter production, moving beyond the adiabatic matching approach and offering new analytic tools.

Findings

Residual coherent field component affects relic abundance by an O(1) factor.

Analytic solutions for symmetry-breaking transition conditions are derived.

Numerical simulations validate the homogeneous sector description in cosmological backgrounds.

Abstract

The relic abundance of vector dark matter originating from an inherited axion-$SU(2)$ condensate is typically determined by implementing an adiabatic matching procedure across the symmetry-breaking transition. We demonstrate that this outcome does not arise in the generic case. The post-inflationary crossover can instead be formulated as a dynamical quantum quench problem, in which the residual coherent component of the field is characterized by a survival factor that induces an $\mathcal{O}(1)$ renormalization of the standard abundance relation. Expressed in conformal time, the spatially homogeneous condensate dynamics reduce to those of a canonical oscillator with quartic and quadratic self-interactions. This representation enables an analytic determination of the matching conditions across the symmetry-breaking transition, the derivation of the corresponding quench work and excess energy relations, and a quantitative validation of the coherent sector description via numerical simulations in both Minkowski and Friedmann--Robertson--Walker backgrounds. We also formulate the homogeneous fluctuation theory via the diagonal-$SO(3)$ $1 \oplus 3 \oplus 5$ decomposition and isolate a soft traceless-symmetric quintet with a $k=0$ vacuum obstruction, a regulated ultraviolet adiabatic bound, and a positive quartic stabilization term. Collectively, these results refine the theoretical description of inherited non-Abelian dark matter production and establish the necessary infrared framework for subsequent investigations of finite-$k$ gauge--Higgs transfer dynamics.