Thermodynamic conditions governing the optical temperature and chemical potential in nonlinear highly multimoded photonic systems
arXiv:1908.01708 · doi:10.1364/OL.44.003936
The paper derives conditions under which weakly nonlinear, highly multimode photonic systems reach thermodynamic equilibrium with a well-defined temperature and chemical potential, identifying when these temperatures are positive or negative based on the linear spectrum, input power, and Hamiltonian invariants.
Abstract
We show that, in general, any complex weakly nonlinear highly multimode system can reach thermodynamic equilibrium that is characterized by a unique temperature and chemical potential. The conditions leading to either positive or negative temperatures are explicitly obtained in terms of the linear spectrum of the system, the input power, and the corresponding Hamiltonian invariant. Pertinent examples illustrating these results are provided in various scenarios.