Model study of dissipation in quantum phase transitions
Abstract
We consider a prototypical system of an infinite range transverse field Ising model coupled to a bosonic bath. By integrating out the bosonic degrees, an effective anisotropic Heisenberg model is obtained for the spin system. The phase diagram of the latter is calculated as a function of coupling to the heat bath and the transverse magnetic field. Collective excitations at low temeratures are assessed within a spin-wave like analysis that exhibits a vanishing energy gap at the quantum critical point. We also consider another limit where the system reduces to a generalized spin-boson model of two interacting spins. By increasing the coupling strength with the heat bath, the two-spin wavefunction changes from an entangled state to a factorized state of two spins which are aligned along the transverse field. We also discuss the possible realization and application of the model to different physical systems.
Cite
@article{arxiv.1104.5306,
title = {Model study of dissipation in quantum phase transitions},
author = {Subhasis Sinha and Sushanta Dattagupta},
journal= {arXiv preprint arXiv:1104.5306},
year = {2011}
}