Hi! These days I've been studying thermodynamics of quantum systems, and in so a very basic doubt come to me... I hope you guys can help me: When we study the usual hamiltonians of quantum mechanics (H-atom, harmonic oscillator, etc.)... Are these hamiltonians modeling the system at temperature 0? How can the temperature be adjusted in the hamiltonian? More concretely: How do I study a quantum harmonic oscillator at temperature 0 and how do I do it at finite temperature? Thanks!