The mean-field quantum Heisenberg ferromagnet via representation theory

Mean field theory of a quantum heisenberg spin glass

A full mean-field solution of a quantum Heisenberg spin-glass model is presented in a large- N limit. A spin-glass transition is found for all values of the spin S. The quantum critical regime associated with the quantum transition at S = 0 and the various regimes in the spin-glass phase at high spin are analyzed. The specific heat is shown to vanish linearly with temperature. In the spin-glass...

Mean field theory for Heisenberg spin glasses

2014 The infinite-ranged spin glass model is studied in the general case of m-component spins. Results for the magnetization laws, the shape of the phase diagram, the nature of the transitions are presented. J. Physique LETTRES 42 (1981) L-103 L-106 1 PI MARS 1981, Classification Physics Abstracts 05.50 75.50K The infinite-ranged model [1], introduced by D. Sherrington and S. Kirkpatrick (SK), ...

Quantum Stability for the Heisenberg Ferromagnet

Highly spinning classical strings on R×S are described by the Landau– Lifshitz model or equivalently by the Heisenberg ferromagnet in the thermodynamic limit. The spectrum of this model can be given in terms of spectral curves. However, it is a priori not clear whether any given admissible spectral curve can actually be realised as a solution to the discrete Bethe equations, a property which ca...

Quantum Field Theory in the Heisenberg Picture

A Polymer Expasion for the Quantum Heisenberg Ferromagnet Wave Function

A polymer expansion is given for the Quantum Heisenberg Ferromagnet wave function. Working on a finite lattice, one is dealing entirely with algebraic identities; there is no question of convergence. The conjecture to be pursued in further work is that effects of large polymers are small. This is relevant to the question of the utility of the expansion and its possible extension to the infinite...