Prog. Theor. Phys. Vol. 48 No. 2 (1972) pp. 407-432
A Thermodynamic Perturbation Theory of the Anharmonic Oscillator. I
— Partition Function and Free Energy
Department of Physics, Boston University, Boston, Massachusetts 02215, U.S.A.
(Received March 1, 1972)
A new formalism of the thermodynamic perturbation theory for the quantum-anharmonic oscillator is proposed. By this method, for each order of the perturbation series, the partition function and the free energy of the system can be obtained in a compact form which is expressed by the temperature Green's function of the harmonic quanta. Based upon a unified method, the various expressions of the perturbation series for the partition function and the free energy are also given. It is shown that the perturbation series for the free energy can be naturally formulated in terms of a cluster expansion.
DOI : 10.1143/PTP.48.407
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Citing Article(s) :
Progress of Theoretical Physics Vol. 48 No. 3 (1972) pp. 783-807
A Thermodynamic Perturbation Theory of the Anharmonic Oscillator. II
Shigeo Naya and Armand Siegel