Decoherence induced by interacting quantum spin baths

Abstract

We study decoherence induced on a two-level system coupled to a one-dimensional quantum spin chain. We consider the cases where the dynamics of the chain is determined by the Ising, XY, or Heisenberg exchange Hamiltonian. This model of quantum baths can be of fundamental importance for the understanding of decoherence in open quantum systems, since it can be experimentally engineered by using atoms in optical lattices. As an example, here we show how to implement a pure dephasing model for a qubit system coupled to an interacting spin bath. We provide results that go beyond the case of a central spin coupled uniformly to all the spins of the bath, in particular showing what happens when the bath enters different phases, or becomes critical; we also study the dependence of the coherence loss on the number of bath spins to which the system is coupled and we describe a coupling-independent regime in which decoherence exhibits universal features, irrespective of the system-environment coupling strength. Finally, we establish a relation between decoherence and entanglement inside the bath. For the Ising and the XY models we are able to give an exact expression for the decay of coherences, while for the Heisenberg bath we resort to the numerical time-dependent Density Matrix Renormalization Group.

18 pages, 20 figures

References in corpus (2)

• Real time evolution using the density matrix renormalization group
• A model of deterministic detector with dynamical decoherence

Cited by in corpus (12)

• Quantum many-body theory of qubit decoherence in a finite-size spin bath. II. Ensemble dynamics
• Detection of quantum critical points by a probe qubit
• Direct observation of quantum criticality in Ising spin chains
• Quantum Fidelity and Thermal Phase Transitions
• Operator fidelity susceptibility, decoherence and quantum criticality
• Decoherence induced by a dynamic spin environment (I): The universal regime
• Bang-Bang control of a qubit coupled to a quantum critical spin bath
• Decoherence by a spin thermal bath: Role of the spin-spin interactions and initial state of the bath
• Ramsey interferometry with a spin embedded in a Coulomb chain
• Quantum frustration of dissipation by a spin bath
• Spin chain model for correlated quantum channels
• Coherence loss and recovery of an electron spin coupled inhomogeneously to a one-dimensional interacting spin bath: an adaptive t-DMRG study