Axion dark matter from inflation-driven quantum phase transition

• DOI: 10.48550/arxiv.2402.08716
• Publication Date: 2024-02-13
• Authors: Ameen Ismail; Seung J. Lee; Bingrong Yu
• Keywords: High Energy Physics - Theory; High Energy Physics - Phenomenology; High Energy Physics - Experiment (hep-ex); High Energy Physics - Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th); FOS: Physical sciences; General Relativity and Quantum Cosmology (gr-qc); General Relativity and Quantum Cosmology; Astrophysics - Cosmology and Nongalactic Astrophysics; High Energy Physics - Experiment

We propose a new mechanism to produce axion dark matter from inflationary fluctuations. Quantum fluctuations during inflation are strengthened by coupling of the kinetic term inflaton, which we parametrize as an effective curvature $\kappa$ in equation motion. A nonvanishing breaks scale invariance power spectrum, driving quantum phase transition with order parameter. The spectrum is proportional inverse comoving horizon $\kappa$. For positive gets red tilt, leading exponential enhancement abundance shrinks inflation. This allows sufficient production comprise entire relic despite ultralight mass. Our predicts significantly different parameter space usual misalignment mechanism. It for axion-like particle much lower decay constant and thus larger Standard Model particles. Much can be probed future experiments including haloscopes, nuclear clocks, CMB-S4. also generate heavier QCD than