Stability of Axion--SU(2) Chromomagnetic Condensates with Stochastic Spin-2 Dressing

Abstract

We investigate whether a stochastic spin-2 gauge-field background can stabilize the chromomagnetic condensate of axion--SU(2) Yang--Mills theory at fixed axion Noether charge in flat spacetime. By coarse-graining the gauge field, we uncover a new class of statistically homogeneous and isotropic spin-2-dressed chromomagnetic condensates satisfying the classical background equations. We then study their fluctuations in two steps. First, at the mean-field (Hartree) level, we determine the fluctuation spectrum and the region where all modes remain positively gapped. Second, we include the leading scattering corrections from fluctuations propagating through the stochastic background. We find that gap survival is controlled by non-Gaussian correlations of the dressing. Statistical positivity constrains the otherwise undetermined higher-point contributions through model-independent consistency conditions, without fixing their detailed momentum dependence. These bounds separate the Hartree-gapped region into a part where a positive Born-level gap is ruled out and a part where stability remains possible. The results are relevant to non-Abelian gauge condensates in early-universe cosmology, including inflation, dark energy, and primordial gravitational waves, and to QCD-like gauge sectors above confinement where thermal effects are subleading.