Low-temperature thermodynamics of finite and discrete quartic quantum oscillator in one dimension

Abstract

I.' this work we examined a quartic Hamiltonian using two different approaches. We first introduced a mean-field Gaussian approximation in order to handle this Hamiltonian analytically and observed that this approximation is insufficient for all coupling strengths. Hence we applied second and third order non-degenerate time-independent perturbation and obtained third or- ■ ler correcHo