Cumulant expansion for systems with large spins

Abstract

A method is proposed for obtaining a systematic expansion of thermodynamic functions of spin systems with large spin S in powers of 1/S. It uses the cumulant technique and a coherent-state representation of the partition function Z. The expansion of Z in terms of cumulants yields an effective classical Hamiltonian with temperature-dependent quantum corrections. For the Heisenberg quantum Hamiltonian, they have a non-Heisenberg form. The effective Hamiltonian can be solved by methods familiar for classical systems.

6 pages, 6 figures. Final published version

References in corpus (1)

• Self-Consistent Gaussian Approximation for Classical Spin Systems: Thermodynamics

Cited by in corpus (7)

• Quadrupolar correlations and spin freezing in S = 1 triangular lattice antiferromagnets
• Inertia effects in the real-time dynamics of a quantum spin coupled to a Fermi sea
• The Free Energy of the Quantum Heisenberg Ferromagnet at Large Spin
• Quantum Nonlinear Switching Model
• Thermodynamic properties of the ferrimagnetic spin chains in the presence of a magnetic field
• Cumulant expansion for ferrimagnetic spin (S_1, s_2) systems
• Semiclassical approach to the thermodynamics of spin chains