Liouvillian gap and single spin-flip dynamics in the dissipative Fermi-Hubbard model

Motivated by recent progress in cold-atom experiments, we analyze the SU($N$) Fermi-Hubbard model on a $d$-dimensional hypercubic lattice with two-body loss. By focusing on states near the ferromagnetic steady states, we obtain the Liouvillian gap in closed form for any $d$ and $N$. We also investigate the dynamics of a ferromagnetic initial state with a single spin flip both analytically and numerically. In particular, we show that, by decreasing the strength of the interaction and loss, the survival probability of the spin flip exhibits a crossover from the power-law decay to the exponential decay. We expect that our findings can be tested experimentally with ultracold alkaline-earth-like atoms in an optical lattice.