Disentanglement and decoherence in two-spin and three-spin systems under dephasing

Ann, Kevin; Jaeger, Gregg

doi:10.1103/physrevb.75.115307

Cited by 51 publications

(31 citation statements)

References 19 publications

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“…A similar conclusion also holds for the other type of entangled state α|11 + β|11 . This relationship between decoherence and disentanglement has also been observed before in spin-boson type models when the two qubits are coupled to separate bosonic baths [57,58].…”

Section: B Disentanglement Of Two Initially Entangled Qubitssupporting

confidence: 82%

“…ESD and subsequent revivals have also been observed to occur in two qubits when they are coupled to classical interacting spin baths [53] and external fields [54], the latter of which has been demonstrated experimentally [55], and to stochastic noise sources [56]. Furthermore, understanding the relation between decoherence and disentanglement is believed to be of importance both for the foundations of quantum mechanics and practical applications in quantum information science [50,[57][58][59][60]. In this work, by taking the bath's initial state as the ground state of the XX chain, we first study the decoherence of a single qubit immersed in the XX bath.…”

Section: Introductionmentioning

confidence: 99%

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

Nanduri

Rabitz

2014

Phys. Rev. A

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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. Next, 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 qubitbath 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.

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Section: B Disentanglement Of Two Initially Entangled Qubitssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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

Nanduri

Rabitz

2014

Phys. Rev. A

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“…Clearly, such finite-time disentanglement can seriously affect applications of entangled states in quantum information processing. The initial report of ESD in two-qubit entangled states in a specific model was later explored in wider contexts and in higher dimensions of Hilbert space when the qubits are replaced by qutrits or qudits [4,5,6,7,8,9,10,11]. The experimental evidences for this effect have been reported for optical setups [12] and atomic ensembles [13].…”

Section: Introductionmentioning

confidence: 99%

Distillability sudden death in qutrit-qutrit systems under global and multilocal dephasing

Ali

2010

Phys. Rev. A

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Recently Song et al., Phys. Rev. A 80, 012331 (2009), have discovered that certain two-qutrit entangled states interacting with multi-local decoherence undergo distillability sudden death whereas their locally equivalent states do not exhibit such behavior. We have found that their basic equation of motion missed some terms and therefore the subsequent calculations and conclusions are not correct/valid except that distillability sudden death may occur. We provide the missing terms and point out the corrections which must be done in the literature to remove confusion. Moreover, we have studied this feature for certain entangled states under global, collective and multi-local decoherence. We have found that entanglement sudden death and distillability sudden death may happen under global and multi-local noises. Moreover, local unitary transformations can not avoid distillability sudden death.

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“…[24,25]. The basic difference lies in the fact that memory states in our formulation do not transform unitarily.…”

Section: Resultsmentioning

confidence: 99%

“…The basic difference lies in the fact that memory states in our formulation do not transform unitarily. Decoherence in our framework results from memory operations and not from unwanted couplings with the environment or dephasing noise [25]. However, our use of quaternions in the time-dependent Schrödinger equation with two coupled channels brings forth a geometric interpretation of scattering which is analogous to the action of the Lorentz group on qubit states [24].…”

Section: Resultsmentioning

confidence: 99%

Impurity and quaternions in nonrelativistic scattering from a quantum memory

Margetis

Grillakis

2008

J. Phys. A: Math. Theor.

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Models of quantum computing rely on transformations of the states of a quantum memory. We study mathematical aspects of a model proposed by Wu in which the memory state is changed via the scattering of incoming particles. This operation causes the memory content to deviate from a pure state, i.e. induces impurity. For nonrelativistic particles scattered from a two-state memory and sufficiently general interaction potentials in (1+1) dimensions, we express impurity in terms of quaternionic commutators. In this context, pure memory states correspond to null hyperbolic quaternions. In the case with point interactions, the scattering process amounts to appropriate rotations of quaternions in the frequency domain. Our work complements previous analyses by Margetis and Myers (2006 J. Phys. A 39 11567).

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Disentanglement and decoherence in two-spin and three-spin systems under dephasing

Cited by 51 publications

References 19 publications

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

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

Distillability sudden death in qutrit-qutrit systems under global and multilocal dephasing

Impurity and quaternions in nonrelativistic scattering from a quantum memory

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