The three-level-amplifier is the template of a quantum device. It operates by employing a hot and cold bath to maintain population inversion between two energy levels which is used to amplify light by stimulated emission The ground state level (1-g) and the excited level (3-h) are coupled to a hot bath of temperature T h . The energy gap is ℏ ℏ ω ω h = E 3 − − E 1 . When the population on the levels equilibrate