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We obtain exact dynamics of a two-qubit central spin model (CSM) consisting of two interacting qubits homogeneously coupled to a spin bath via the $XXZ$-type coupling, with the bath initially prepared in linear superpositions of the…

Quantum Physics · Physics 2020-09-17 Zejiang Li , Pei Yang , Wen-Long You , Ning Wu

An exact reduced dynamical map along with its operator sum representation is derived for a central spin interacting with a thermal spin environment. The dynamics of the central spin shows high sustainability of quantum traits such as…

Quantum Physics · Physics 2017-11-23 Chiranjib Mukhopadhyay , Samyadeb Bhattacharya , Avijit Misra , Arun Kumar Pati

We calculate exactly the time-dependent reduced density matrix for the central spin in the central-spin model with homogeneous Heisenberg couplings. Therefrom, the dynamics and the entanglement entropy of the central spin are obtained. A…

Statistical Mechanics · Physics 2009-11-11 Michael Bortz , Joachim Stolze

We study the dynamics of a single spin-1/2 coupled to a bath of spins-1/2 by inhomogeneous Heisenberg couplings including a central magnetic field. This central-spin model describes decoherence in quantum bit systems. An exact formula for…

Statistical Mechanics · Physics 2009-11-11 Michael Bortz , Joachim Stolze

Maintaining coherence of a qubit is of vital importance for realizing a large-scale quantum computer in practice. In this work, we study the central spin decoherence problem in the $XXX$ central spin model (CSM) and focus on the quantum…

Quantum Physics · Physics 2020-11-10 Qing-Kun Wan , Hai-Long Shi , Xu Zhou , Xiao-Hui Wang , Wen-Li Yang

We consider here the problem of a "central spin", with spin quantum number $S \gg 1$, interacting with a set of microscopic spins. Interactions between the microscopic spins are ignored. This model describes magnetic grains or magnetic…

Condensed Matter · Physics 2016-08-31 N. V. Prokof'ev , P. C. E. Stamp

The dynamics and decoherence of an electronic spin-1/2 qubit coupled to a bath of nuclear spins via hyperfine interactions in a quantum dot is studied. We show how exact results from the integrable solution can be used to understand the…

Strongly Correlated Electrons · Physics 2010-10-22 Michael Bortz , Sebastian Eggert , Christian Schneider , Robert Stubner , Joachim Stolze

In this review, we discuss the decoherence and thermalization of a quantum spin system interacting with a spin bath environment, by numerically solving the time-dependent Schr\"{o}dinger equation of the whole system. The effects of the…

Quantum Physics · Physics 2010-05-27 Shengjun Yuan

The reduced dynamics of a single or two qubits coupled to an interacting quantum spin bath modeled by a XXZ spin chain is investigated. By using the method of time-dependent density matrix renormalization group (t-DMRG), we go beyond the…

Strongly Correlated Electrons · Physics 2013-04-04 Cheng-Yan Lai , Jo-Tzu Hung , Chung-Yu Mou , Pochung Chen

The counter rotating-wave term (CRT) effects from the system-bath coherence on the dynamics of quantum correlation of two qubits in two independent baths and a common bath are systematically investigated. The hierarchy approach is extended…

Quantum Physics · Physics 2013-10-21 Chen Wang , Qing-Hu Chen

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…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Ning Wu , Nina Fröhling , Xi Xing , Johannes Hackmann , Arun Nanduri , Frithjof B. Anders , Herschel Rabitz

The dynamics of a spin-1/2 particle coupled to a nuclear spin bath through an isotropic Heisenberg interaction is studied, as a model for the spin decoherence in quantum dots. The time-dependent polarization of the central spin is…

Quantum Physics · Physics 2007-06-28 D. D. Bhaktavatsala Rao , V. Ravishankar , V. Subrahmanyam

We investigate hyperfine induced electron spin and entanglement dynamics in a system of two quantum dot spin qubits. We focus on the situation of zero external magnetic field and concentrate on approximation-free theoretical methods. We…

Mesoscale and Nanoscale Physics · Physics 2010-07-02 Bjoern Erbe , John Schliemann

We solve the long-standing central spin problem for a general set of inhomogeneous bath couplings and a large class of initial bath states. We compute the time evolution of the coherence of a central spin coupled to a spin bath by resumming…

Mesoscale and Nanoscale Physics · Physics 2012-10-09 Edwin Barnes , Łukasz Cywiński , S. Das Sarma

We study the behavior of the Rabi oscillations of a driven central spin (qubit) coupled to an antiferromagnetic spin bath (environment). It is found that the decoherence behavior of the central spin depends on the detuning, driving…

Quantum Physics · Physics 2011-02-11 Xiao-Zhong Yuan , Hsi-Sheng Goan , Ka-Di Zhu

We describe a simple quantum mechanical method that can be used to obtain accurate numerical results over long time scales for the spin correlation tensor of an electron spin that is hyperfine coupled to a large number of nuclear spins.…

Quantum Physics · Physics 2018-08-13 Lachlan P. Lindoy , David E. Manolopoulos

Exactly solvable models provide an opportunity to study different aspects of reduced quantum dynamics in detail. We consider the reduced dynamics of a single spin in finite XX and XY spin 1/2 chains. First we introduce a general expression…

Quantum Physics · Physics 2015-03-17 Oleg Lychkovskiy

Combining highly coherent spin control with efficient light-matter coupling offers great opportunities for quantum communication and networks, as well as quantum computing. Optically active semiconductor quantum dots have unparalleled…

By applying complementary analytic and numerical methods, we investigate the dynamics of spin-$1/2$ XXZ models with variable-range interactions in arbitrary dimensions. The dynamics we consider is initiated from uncorrelated states that are…

Quantum critical chains are well described and understood by virtue of conformal field theory. Still the meaning of the real space entanglement spectrum -- the eigenvalues of the reduced density matrix -- of such systems remains in general…

Strongly Correlated Electrons · Physics 2015-06-23 Nicolas Laflorencie , Stephan Rachel
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