undecohered

Then use is made of the relative entropy between undecohered and decohered squeezed states whose monotonicity gives the zeroth and the second law, while the first law can be obtained either by the vanishing of the first derivative of relative entropy or by studying the effective thermal model generated by the modular Hamiltonian.

2015, Xiao-Kan Guo, “Black hole thermodynamics from decoherence”, in arXiv