Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 0707.2372

Importance of bath dynamics for decoherence in spin systems

Shengjun Yuan·Mikhail I. Katsnelson·Hans De Raedt
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study the decoherence of two coupled spins that interact with a chaotic spin-bath environment. It is shown that connectivity of spins in the bath is of crucial importance for the decoherence of the central system. The previously found phenomenon of two-step decoherence (Phys. Rev. Lett. {\bf 90}, 210401 (2003)) turns out to be typical for the bath with a slow enough dynamics or no dynamics. For a generic random system with chaotic dynamics a conventional exponential relaxation to the pointer states takes place. Our results confirm a conjecture of Paz and Zurek (Phys. Rev. Lett. {\bf 82}, 5181 (1999)) that for weak enough interactions the pointer states are eigenstates of the central system.

Explore related subjects

cond-mat.otherquant-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Shengjun Yuan, Mikhail I. Katsnelson, Hans De Raedt. 2007-07-16. Importance of bath dynamics for decoherence in spin systems. https://arxiv.org/abs/0707.2372

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Occupancy Driven Phase Transitions in Gapped Systems

Systems characterized by an energy gap between the ground state and excited states support a growing number of thermal excitations upon raising the temperature. Provided these excitations interact with each other, their number affects the size of the energy gap akin to a harmonic oscillator where the oscillation frequency is damping dependent. Here we show that once a critical number of excitations is reached, the excitation population becomes thermodynamically unstable and the system transitions between two states. This transition is marked by a divergence in the specific heat, which does not have to be accompanied by an order parameter, nor by the full closure of the gap. We illustrate the thermodynamics using a simple two level system and superfluid $^4$He as examples, and we argue that the hidden order transition in URu$_2$Si$_2$ is an example of such an occupancy driven transition in the absence of an order parameter.

cond-mat.other↗
arXiv2026

When can phonon modes be trapped by arbitrarily weak local defects? Rigorous sufficient conditions in a monatomic lattice

Although many studies have shown that localized defects in vibrational lattices can trap localized phonon modes for particular geometries, there has been no general proof of localization for arbitrary localized defects of arbitrarily weak strength. This is distinct from the problem of Anderson localization, where random perturbations are spread across the entire lattice and one aims to prove whether all states become localized. Here, we study the former problem for monatomic 1d and 2d crystals with nearest-neighbor harmonic interactions, corresponding in 2d to square lattices of masses and springs, and prove that arbitrary localized perturbations (such as any finite set of defect masses) that decrease the net mass by any amount must lead to localized states. In contrast, the analogous statement is generally false in 3d. Our proof employs a straightforward variational method, inspired by analogous results for the Schrödinger and Maxwell equations, that should be extensible to other discrete systems.

cond-mat.other↗
arXiv2026

Chiral near-fields at achiral plasmonic tips enable nanoscale valley polarimetry

Optical helicity is central to chiral light-matter interactions, yet plasmonic confinement typically distorts it at the nanoscale. Here, we demonstrate nanoscale valley polarimetry using an achiral Au tip, where incidence-angle control of circularly polarized light creates a strongly localized, helicity-preserving near-field. Chiral tip-enhanced photoluminescence (c-TEPL) directly resolves and reverses local valley polarization in monolayer WSe2 and reveals nanoscale polarization variations in strained MoS2 hidden by diffraction-limited measurements.

cond-mat.other↗