Theoretical analysis of monopole-mode damping in a nearly spherical unitary Fermi gas
Phys. Rev. A 113, 013303 – Published 2 January, 2026
DOI: https://doi.org/10.1103/5ykf-zzrr
Abstract
We present a comprehensive theoretical investigation of the damping of the monopole mode in strongly interacting Fermi gases confined close to spherical symmetry. Within a hydrodynamic scaling framework, we systematically account for deviations from ideal conditions, including trap anisotropy, anharmonicity, and finite detuning from unitarity. By treating these effects perturbatively, we derive analytical expressions for frequency shifts and damping rates of collective modes. Our analysis reveals that trap-induced symmetry breaking and interaction-induced corrections constitute the primary damping mechanisms, arising from mode coupling between monopole and quadrupole excitations. The results establish a unified theoretical framework that quantitatively captures recent observations of long-lived breathing oscillations and clarify the roles of geometry and interactions in shaping collective dynamics of strongly correlated quantum gases.
