arXiv:cond-mat/0212248 · Physical Review Letters
Spectrum and Correlation Functions of a Quasi-One-Dimensional Quantum Ising Model
Sam T. Carr, Alexei M. Tsvelik
Abstract
For a model of weakly coupled quantum Ising chains we outline the phase diagram and establish that well below the transition line the system has a remarkably one-dimensional spectrum. We study the dynamical magnetic susceptibility and find a very rich spectrum with several modes corresponding to a fundamental particle and its bound states. The approach is based on the Bethe ansatz and the random phase approximation applied to the interchain exchange.