Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1202.0676 · Physical Review A

Importance of level statistics in the decoherence of a central spin due to a spin environment

Håkon Brox, Joakim Bergli, Y. M. Galperin

Published May 17, 2012• 8 citations
arXivHTMLPDF

Abstract

We study the decoherence of a central spin $1/2$ due to a closed environment composed of spin-$1/2$ particles. It is known that a frustrated spin environment, such as a spin glass, is much more efficient for decoherence of the central spin than a similar-size environment without frustration. We construct a Hamiltonian where the degree of frustration is parametrized by a single parameter $\ensuremath{\kappa}$. By use of this model we find that the environment can be classified by two distinct regimes with respect to the strength of level repulsion. These regimes behave qualitatively different with respect to decoherence of the central spin and might explain the strong enhancement of decoherence observed for frustrated environments.

DOI
10.1103/physreva.85.052117

Related papers

Giant enhancement of quantum decoherence by frustrated environments

S. Yuan, Mikhail I. Katsnelson, Hans A. De Raedt

Decoherence in a system of two antiferromagnetically coupled spins that interact with a spin bath environment is studied. Systems are considered that range from the rotationally invariant to highly anisotropic spin models and have different topologies and values of parameters that are fixed or are allowed to fluctuate randomly. We explore the conditions under which the two-spin system clearly shows an evolution from the initial spin-up-spin-down state towards the maximally entangled singlet state. We demonstrate that frustration and, especially, glassiness of the spin environment strongly enhances the decoherence of the two-spin system.

arXiv:quant-ph/0512232•Journal of Experimental and Theoretical Physics Letters•Sep 1, 2006•18 citations

Giant enhancement of quantum decoherence by frustrated environments

Yuan, S, Mikhail I. Katsnelson, Hans A. De Raedt

This Letter studies the decoherence in a system of two antiferromagnetically coupled spins that interact with a spin bath environment. Systems are considered that range from the rotationally invariant to highly anisotropic spin models, have different topologies and values of parameters that are fixed or are allowed to fluctuate randomly. We explore the conditions under which the two-spin system clearly shows an evolution from the initial spin-up - spin-down state towards the maximally entangled singlet state. We demonstrate that frustration and, especially, glassiness of the spin environment strongly enhances the decoherence of the two-spin system.

•Dec 25, 2005•10 citations

Decoherence from spin environments

Fernando Cucchietti, Juan Pablo Paz, Wojciech Hubert Zurek

We examine two exactly solvable models of decoherence---a central spin-system, (i) with and (ii) without a self-Hamiltonian, interacting with a collection of environment spins. In the absence of a self-Hamiltonian we show that in this model (introduced some time ago to illustrate environment-induced superselection) generic assumptions about the coupling strengths can lead to a universal (Gaussian) suppression of coherence between pointer states. On the other hand, we show that when the dynamics of the central spin is dominant a different regime emerges, which is characterized by a non-Gaussian decay and a dramatically different set of pointer states. We explore the regimes of validity of the Gaussian decay and discuss its relation to the spectral features of the environment and to the Loschmidt echo (or fidelity).

arXiv:quant-ph/0312207•Physical Review A•Nov 29, 2005•220 citations

Decoherence by a spin thermal bath: Role of spin-spin interactions and initial state of the bath

Shengjun Yuan, Mikhail I. Katsnelson, Hans A. De Raedt

We study the decoherence of two coupled spins that interact with a spin-bath environment. It is shown that the connectivity and the coupling strength between the spins in the environment are of crucial importance for the decoherence of the central system. For the anisotropic spin bath, changing the connectivity or coupling strength changes the decoherence of the central system from Gaussian to exponential decay law. The initial state of the environment is shown to affect the decoherence process in a qualitatively significant manner.

arXiv:0711.2483•Physical Review B•May 7, 2008•36 citations

Enhanced decoherence in the vicinity of a phase transition

S. Camalet

We study the decoherence of a spin-1/2 induced by an environment which is on the verge of a continuous phase transition. We consider spin environments described by the ferromagnetic and antiferromagnetic Heisenberg models on a square lattice. As is well known, these two dimensional systems undergo a continuous phase transition at zero temperature, where, the spins order spontaneously. For weak coupling of the central spin to these baths, we find that as one approaches the transition temperature, critical fluctuations make the central spin decohere faster. Furthermore, the decoherence is maximal at zero temperature as signalled by the divergence of the Markovian decoherence rate.

arXiv:0706.2127•Jun 14, 2007•0 citations

Parity effects in spin decoherence

Akakii Melikidze, V. V. Dobrovitski, Hans A. De Raedt +2 more

We demonstrate that decoherence of many-spin systems can drastically differ from decoherence of single-spin systems. The difference originates at the most basic level, being determined by parity of the central system, i.e., by whether the system comprises even or odd number of spin-$1∕2$ entities. Therefore, it is very likely that similar distinction between the central spin systems of even and odd parity is important in many other situations. Our consideration clarifies the physical origin of the unusual two-step decoherence found previously in the two-spin systems.

arXiv:quant-ph/0212097•Physical Review B•Jul 30, 2004•64 citations
We study the decoherence of a central spin 1/21/21/2 due to a closed environment composed of spin-1/21/21/2 particles. It is known that a frustrated spin environment, such as a spin glass, is much more efficient for decoherence of the central spin than a similar-size environment without frustration. We construct a Hamiltonian where the degree of frustration is parametrized by a single parameter \ensuremathκ\ensuremath{\kappa}\ensuremathκ. By use of this model we find that the environment can be classified by two distinct regimes with respect to the strength of level repulsion. These regimes behave qualitatively different with respect to decoherence of the central spin and might explain the strong enhancement of decoherence observed for frustrated environments.
Decoherence in a system of two antiferromagnetically coupled spins that interact with a spin bath environment is studied. Systems are considered that range from the rotationally invariant to highly anisotropic spin models and have different topologies and values of parameters that are fixed or are allowed to fluctuate randomly. We explore the conditions under which the two-spin system clearly shows an evolution from the initial spin-up-spin-down state towards the maximally entangled singlet state. We demonstrate that frustration and, especially, glassiness of the spin environment strongly enhances the decoherence of the two-spin system.
This Letter studies the decoherence in a system of two antiferromagnetically coupled spins that interact with a spin bath environment. Systems are considered that range from the rotationally invariant to highly anisotropic spin models, have different topologies and values of parameters that are fixed or are allowed to fluctuate randomly. We explore the conditions under which the two-spin system clearly shows an evolution from the initial spin-up - spin-down state towards the maximally entangled singlet state. We demonstrate that frustration and, especially, glassiness of the spin environment strongly enhances the decoherence of the two-spin system.
We examine two exactly solvable models of decoherence---a central spin-system, (i) with and (ii) without a self-Hamiltonian, interacting with a collection of environment spins. In the absence of a self-Hamiltonian we show that in this model (introduced some time ago to illustrate environment-induced superselection) generic assumptions about the coupling strengths can lead to a universal (Gaussian) suppression of coherence between pointer states. On the other hand, we show that when the dynamics of the central spin is dominant a different regime emerges, which is characterized by a non-Gaussian decay and a dramatically different set of pointer states. We explore the regimes of validity of the Gaussian decay and discuss its relation to the spectral features of the environment and to the Loschmidt echo (or fidelity).
We study the decoherence of two coupled spins that interact with a spin-bath environment. It is shown that the connectivity and the coupling strength between the spins in the environment are of crucial importance for the decoherence of the central system. For the anisotropic spin bath, changing the connectivity or coupling strength changes the decoherence of the central system from Gaussian to exponential decay law. The initial state of the environment is shown to affect the decoherence process in a qualitatively significant manner.
We study the decoherence of a spin-1/2 induced by an environment which is on the verge of a continuous phase transition. We consider spin environments described by the ferromagnetic and antiferromagnetic Heisenberg models on a square lattice. As is well known, these two dimensional systems undergo a continuous phase transition at zero temperature, where, the spins order spontaneously. For weak coupling of the central spin to these baths, we find that as one approaches the transition temperature, critical fluctuations make the central spin decohere faster. Furthermore, the decoherence is maximal at zero temperature as signalled by the divergence of the Markovian decoherence rate.
We demonstrate that decoherence of many-spin systems can drastically differ from decoherence of single-spin systems. The difference originates at the most basic level, being determined by parity of the central system, i.e., by whether the system comprises even or odd number of spin-1∕21∕21∕2 entities. Therefore, it is very likely that similar distinction between the central spin systems of even and odd parity is important in many other situations. Our consideration clarifies the physical origin of the unusual two-step decoherence found previously in the two-spin systems.