Interaction Corrections to SpinWave Theory in the LargeS Limit of the Quantum Heisenberg Ferromagnet
Abstract
The Quantum Heisenberg Ferromagnet can be naturally reformulated in terms of interacting bosons (called spin waves or magnons) as an expansion in the inverse spin size. We calculate the first order interaction correction to the free energy, as an upper bound in the limit where the spin size S to ∞ and ß S is fixed ( ß being the inverse temperature). Our result is valid in two and three spatial dimensions. We extrapolate our result to compare with Dyson's lowtemperature expansion. While our firstorder correction has the expected temperature dependence, in higher orders of the perturbation theory cancellations are necessary.
 Publication:

Mathematical Physics, Analysis and Geometry
 Pub Date:
 June 2017
 DOI:
 10.1007/s1104001692376
 arXiv:
 arXiv:1604.02548
 Bibcode:
 2017MPAG...20....5B
 Keywords:

 Mathematical Physics;
 Condensed Matter  Statistical Mechanics
 EPrint:
 13 pages, 1 diagram