Magnon energy renormalization and low-temperature thermodynamics of O(3) Heisenberg ferromagnets

Journal Article · Sun Dec 15 00:00:00 EST 2013 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/J.AOP.2013.09.012· OSTI ID:22224264

Pantić, Milan R.; Pavkov-Hrvojević, Milica V.; Kapor, Darko V.

We present the perturbation theory for lattice magnon fields of the D-dimensional O(3) Heisenberg ferromagnet. The effective Hamiltonian for the lattice magnon fields is obtained starting from the effective Lagrangian, with two dominant contributions that describe magnon–magnon interactions identified as a usual gradient term for the unit vector field and a part originating in the Wess–Zumino–Witten term of the effective Lagrangian. Feynman diagrams for lattice scalar fields with derivative couplings are introduced, on the basis of which we investigate the influence of magnon–magnon interactions on magnon self-energy and ferromagnet free energy. We also comment appearance of spurious terms in low-temperature series for the free energy by examining magnon–magnon interactions and internal symmetry of the effective Hamiltonian (Lagrangian). -- Highlights: •Lattice magnon Hamiltonian constructed from the effective Lagrangian. •New Feynman diagrams with colored propagators and vertices for lattice scalar fields. •Influence of magnon–magnon interactions from the WZW term on magnon energies and free energy of O(3) HFM.

• OSTI ID: 22224264
• Journal Information: Annals of Physics (New York), Vol. 339; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-4916
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
FEYNMAN DIAGRAM
FREE ENERGY
HAMILTONIANS
INTERACTIONS
LAGRANGIAN FUNCTION
LATTICE FIELD THEORY
PERTURBATION THEORY
RENORMALIZATION
SCALAR FIELDS
SELF-ENERGY
THERMODYNAMICS
VECTOR FIELDS