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Rabi oscillations, decoherence, and disentanglement in a qubit-spin-bath system

Author(s): Wu, Ning; Nanduri, Arun; Rabitz, Herschel

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Abstract: We examine the influence of environmental interactions on simple quantum systems by obtaining the exact reduced dynamics of a qubit coupled to a one-dimensional spin bath. In contrast to previous studies, both the qubit-bath coupling and the nearest-neighbor intrabath couplings are taken as the spin-flip XX type. We first study the Rabi oscillations of a single qubit with the spin bath prepared in a spin coherent state, finding that nonresonance and finite intrabath interactions have significant effects on the qubit dynamics. Then we discuss the bath-induced decoherence of the qubit when the bath is initially in the ground state and show that the decoherence properties depend on the internal phases of the spin bath. By considering two independent copies of the qubit-bath system, we finally probe the disentanglement dynamics of two noninteracting entangled qubits. We find that entanglement sudden death appears when the spin bath is in its critical phase. We show that the single-qubit decoherence factor is an upper bound for the two-qubit concurrence.
Publication Date: 9-Jun-2014
Citation: Wu, Ning, Nanduri, Arun, Rabitz, Herschel. (2014). Rabi oscillations, decoherence, and disentanglement in a qubit-spin-bath system. PHYSICAL REVIEW A, 89 (10.1103/PhysRevA.89.062105
DOI: doi:10.1103/PhysRevA.89.062105
ISSN: 1050-2947
EISSN: 1094-1622
Pages: 062105-1 - 062105-15
Type of Material: Journal Article
Journal/Proceeding Title: PHYSICAL REVIEW A
Version: Final published version. Article is made available in OAR by the publisher's permission or policy.



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