Dimensional crossover in ultracold Fermi gases from functional renormalization

We investigate the dimensional crossover from three to two dimensions in an ultracold Fermi gas across the whole BCS-BEC crossover. Of particular interest is the strongly interacting regime as strong correlations and pair fluctuations are more pronounced in reduced dimensions. Our results are obtained from first principles within the framework of the functional renormalization group (FRG). Here, the confinement of the transverse direction is imposed by means of periodic boundary conditions. We calculate the equation of state, the gap parameter at zero temperature, and the superfluid transition temperature across a wide range of transversal confinement length scales. Particular emphasis is put on the determination of the finite-temperature phase diagram for different confinement length scales. In the end, our results are compared with recent experimental observations and we discuss them in the context of other theoretical works.

Automated summary

The study investigates the dimensional crossover from three to two dimensions in an ultracold Fermi gas, particularly focusing on the strongly interacting regime where strong correlations and pair fluctuations are more pronounced. Results are obtained from first principles within the framework of the functional renormalization group (FRG) and calculations are carried out across a wide range of transversal confinement length scales. Emphasis is placed on determining the finite-temperature phase diagram for different confinement length scales and comparing the results with recent experimental observations and other theoretical works.