Decoherence of a single spin coupled to an interacting spin bath

Abstract

Decoherence of a central spin coupled to an interacting spin bath via inhomogeneous Heisenberg coupling is studied by two different approaches, namely an exact equations of motion (EOMs) method and a Chebyshev expansion technique (CET). By assuming a wheel topology of the bath spins with uniform nearest-neighbor XX-type intrabath coupling, we examine the central spin dynamics with the bath prepared in two different types of bath initial conditions. For fully polarized baths in strong magnetic fields, the polarization dynamics of the central spin exhibits a collapserevival behavior in the intermediate-time regime. Under an antiferromagnetic bath initial condition, the two methods give excellently consistent central spin decoherence dynamics for finite-size baths of N ≤ 14 bath spins. The decoherence factor is found to drop off abruptly on a short time scale and approach a finite plateau value which depends on the intrabath coupling strength non-monotonically. In the ultrastrong intrabath coupling regime, the plateau values show an oscillatory behavior depending on whether N/2 is even or odd. The observed results are interpreted qualitatively within the framework of the EOM and perturbation analysis. The effects of anisotropic spin-bath coupling and inhomogeneous intrabath bath couplings are briefly discussed. Possible experimental realization of the model in a modified quantum corral setup is suggested.

Spin noise of electrons and holes in (In,Ga)As quantum dots: Experiment and theory

“…For the opposite limit, A k ≪ q k , the nuclear system must be diagonalized first, providing a set of two time-reversal doublets as the new eigenbasis for each nuclear spin energetically separated by 2q k 1 + η 2 4/3. Then the coupling to the electron/hole spin is treated perturbatively, and the rigidity of the nuclear system can suppress additional dephasing for η → 0 [24,56].…”

Relaxation of antiferromagnetic order and growth of Rényi entropy in a generalized Heisenberg star

“…In spite of the technical difficulties, it is however interesting and important to take into account the effect of environmental self-interaction on the central spin dynamics, as demonstrated in an early work using a fully connected * Electronic address: wunwyz@gmail.com spin−spin-bath model [21]. Recently, there appeared several theoretical works in which the decoherence of a qubit coupled to interacting quantum spin chains are investigated [22][23][24]. Among these, Wu et al studied the decoherence of a qubit coupled to an XX chain via XX- [22] and XXZ-type [23] hyperfine couplings using an equations-of-motion method and a Chebyshev expansion technique.…”

“…Recently, there appeared several theoretical works in which the decoherence of a qubit coupled to interacting quantum spin chains are investigated [22][23][24]. Among these, Wu et al studied the decoherence of a qubit coupled to an XX chain via XX- [22] and XXZ-type [23] hyperfine couplings using an equations-of-motion method and a Chebyshev expansion technique. Based on the Bethe ansatz solution of the XXX chain, Lu et al obtained the exact decoherence and polarization dynamics of a qubit coupled homogeneously to an XXX bath [24].…”

Single spin probe of many-body localization

“…The study of the decoherence dynamics of a single spin attached to a bath has a long history [25][26][27][28][29][30][31][32] . In particular, the roles of soft modes close to second order phase transition 27,33 , or the presence of a non-vanishing order-parameter in the bath have been studied in depth.…”