Abstract
 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 
kT ≲ 
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 
Cᵥ move towards each other. Such shift in their features finetune 
S and 
Cᵥ relative to their behavior in the absence of two-particle interactions with the bath.