Caloric effects in an open Fermi–Hubbard optical dimer due to onsite and heat bath-induced two-particle interactions

The immersion of the Fermi–Hubbard optical dimer in a mean field Fermi gas, acting as a heat bath, modifies the behavior of the statistical mechanical properties of the particles trapped in it. This is done by varying the two-particle interactions induced by the heat bath and the onsite two-particle interaction U . It is shown that in the presence of the heat bath-induced interaction, the partition function Z drops to a minimum finite value in the repulsive regime of U at the normalized temperature region k B T ≲ t / 2 , where t is the tunneling parameter. In this temperature region, the convergence points of the respective isolines of the entropy S and the heat capacity C V move towards each other. Such shift in their features finetune S and C V relative to their behavior in the absence of two-particle interactions with the bath.