2025/04/27 by Georgii Kalagov, Kalagov, Georgii · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Quantum Gases (cond-mat.quant-gas) #Quantum many-body systems #Statistical Mechanics (cond-mat.stat-mech)
paper · doi:10.48550/arxiv.2504.19310
openalex publication_date 2025/04/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the superfluid phase transition in an SU(N)-symmetric Fermi gas with N distinct spin states using the functional renormalization group. To capture pairing phenomena beyond mean-field theory, we introduce an auxiliary bosonic field and employ the leading order of the derivative expansion of the partially bosonized effective average action. By discretizing the effective potential on a grid and numerically integrating the flow equations, we resolve the thermodynamic behavior near the transition. Our results reveal a fluctuation-induced first-order phase transition for N ≥ 4, which is absent at the mean-field level. In the unitary regime, we provide quantitative predictions for the critical temperature, as well as for the discontinuities in the superfluid gap and entropy density as functions of N. With increasing N, the critical temperature decreases, while the discontinuities become more pronounced, indicating a stronger first-order transition.