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 phase, intriguing connections between the equilibrium properties of the quantum problem and the out-of-equilibrium dynamics of classical models are pointed out.
Georges
A
CNRS-Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 Rue Lhomond, 75005 Paris, France.
Parcollet
O
Sachdev
S