Communications in Theoretical Physics
Analytic Calculation of Arbitrary Matrix Elements for Boson Exponential Quadratic Operators
Pan Jianwei, Hou Guang, Zhang Yongde
Abstract
By means of the transformation relation between the ordinary form of boson exponential quadratic operators (BEQO) and its anti-normal product form, we present an effective method to conveniently calculate arbitrary matrix elements of BEQO. By this method, many important matrix elements can be calculated analytically. As a direct application, we obtain the exact solutions of the density matrix and partition function for general boson quadratic Hamiltonian without any information about the energy level.