Enhanced von Neumann Entropy in Dense Two-Level Ensembles

We investigate the equilibrium properties of the von Neumann entropy in a dense, dipole-dipole coupled ensemble of two-level emitters confined in a fully symmetric Dicke subspace, which additionally interact through a common thermal bath. The static dipole-dipole interactions are assumed to be strong, though remaining smaller than the transition frequency. Consequently, the resulting thermal equilibrium entropy of the ensemble is characterized as a function of these coupling strengths. As a consequence, we have demonstrated that the von Neumann entropy enhances when stronger dipole-dipole couplings among the two-level emitters are being involved. Furthermore, the entropy can even be reduced for an opposite sign of the dipole-dipole coupling strength compared to the former case.