Axion dark matter from inflation-driven quantum phase transition |
Bingrong Yu, Cornell University |
Event Type: Informal HEP Talk |
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Time: 2:00 PM - 3:00 PM |
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Location: 726 Broadway, 940, CCPP Seminar |
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Abstract: We propose a new mechanism to produce axion dark matter from inflationary fluctuations. Quantum fluctuations during inflation are strengthened by a coupling of the axion kinetic term to the inflaton. This coupling acts as an order parameter, breaking the scale invariance of the axion power spectrum and driving a quantum phase transition. A red-tilted spectrum leads to an exponential enhancement of the axion abundance as the comoving horizon shrinks during inflation. This enhancement allows sufficient axion production to comprise the entire dark matter abundance, despite the ultralight mass. Our mechanism predicts a significantly different parameter space from the usual misalignment mechanism, allowing much larger couplings to Standard Model particles, which can be probed by future axion experiments. It is applicable to both QCD axion and axion-like particles. |