Thermal counterparts of nonclassical states in quantum optics.

Finite-temperature generalizations of the important, special families of states in quantum optics are constructed using thermofield dynamics. Fermionic coherent states, fermionic squeezed states, and their thermalized counterparts are also constructed. It is shown that all these states possess a generalized thermal annihilation operator, for which these are eigenstates. Typical correlation functions for these states at finite temperature are evaluated.