Decoherence in the quantum Ising model with transverse dissipative interaction in the strong-coupling regime

Year: 2018

Authors: Weisbrich H., Saussol C., Belzig W., Rastelli G.

Autors Affiliation: Univ Konstanz, Fachbereich Phys, D-78457 Constance, Germany. Univ Konstanz, Zukunftskolleg, D-78457 Constance, Germany.

Abstract: We study the decoherence dynamics of a quantum Ising lattice of finite size with a transverse dissipative interaction, namely, the coupling with the bath is assumed perpendicular to the direction of the spins interaction and parallel to the external magnetic field. In the limit of small transverse field, the eigenstates and spectrum are obtained by a strong-coupling expansion, from which we derive the Lindblad equation in the Markovian limit. At temperature lower than the energy gap and for weak dissipation, the decoherence dynamics can be restricted to take only the two degenerate ground states and the first excited subspace into account. The latter is formed by pairs of topological excitations (domain walls or kinks), which are quantum delocalized along the chain due to the small magnetic field. We find that some of these excited states form a relaxation-free subspace, namely, they do not decay to the ground states.

Journal/Review: PHYSICAL REVIEW A

Volume: 98 (5)      Pages from: 052109  to: 052109

More Information: This work was supported by the German Excellence Initiative through the Zukunftskolleg, the Deutsche Forschung Gemeinschaft (DFG) through the SFB 767, Project No. 32152442, and by the MWK Baden-Wurttemberg Research Seed Capital (RiSC) funding.
KeyWords: decoherence, quantum ising models
DOI: 10.1103/PhysRevA.98.052109