Pseudogap regime of a strongly interacting two-dimensional Fermi gas with and without confinement-induced effect range of interactions

We investigate theoretically the many-body pairing of a strongly correlated two-dimensional Fermi gas with and without negative confinement-induced effective range. Using a strong-coupling effective field theory in the normal state, we show that the specific heat at constant volume can be used as a characteristic indicator of the crossover from the normal Fermi liquid to the pseudogap state in two dimensions. We calculate the pseudogap formation temperature through the specific heat at constant volume, examining the role of a negative confinement-induced effective range on many-body pairing above the superfluid transition. We compare our results with and without effective range to the recent experimental measurement performed with radio-frequency spectroscopy in Murthy et al.[Science359, 452-455 (2018)]. Although a good qualitative agreement is found, we are not able to discriminate the effect of the confinement-induced effect range in the experimental data.