Spin-orbit coupled spin-boson model: A variational analysis
Phys. Rev. B 113, 024438 – Published 29 January, 2026
DOI: https://doi.org/10.1103/p785-pgkr
Abstract
The spin-boson (SB) model is a standard prototype for quantum dissipation, which we generalize in this work, to explore the dissipative effects on a one-dimensional spin-orbit (SO) coupled particle in the presence of a subohmic bath. We analyze this model by extending the well-known variational polaron approach, revealing a localization transition accompanied by an intriguing change in the spectrum, for which the doubly degenerate minima evolves to a single minimum at zero momentum as the system-bath coupling increases. For a translational invariant system with conserved momentum, a continuous magnetization transition occurs, whereas the ground state changes discontinuously. We further investigate the transition of the ground state in the presence of harmonic confinement, which effectively models a quantum-dot-like nanostructure under the influence of the environment. In both scenarios, the entanglement entropy of the spin sector can serve as a marker for these transitions. Interestingly, for the trapped system, a catlike superposition state corresponds to maximum entanglement entropy below the transition, highlighting the relevance of the present model for studying the effect of decoherence on intraparticle entanglement in the context of quantum information processing.
