Quantum discord in non-Markovian environments

Xing, Xiao; Mao-Fa, Fang; Li, Yanling; Kang, Guodong; Chao, Wu

doi:10.1016/j.optcom.2010.03.046

Cited by 24 publications

(12 citation statements)

References 26 publications

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“…In this sense, non-Markovianity has been quantified by a variety of measures [61,[63][64][65][66][67][68][69][70][71][72] and regarded as a precious resource for certain applications [61,70,73]. Although memory effects permit coherence, entanglement and discord of noninteracting subsystems to partially revive after disappearing during the time evolution [48,53,65,[74][75][76][77], these revivals eventually decay. Decoherence remains one of the main drawbacks to overcome towards the implementation of quantum-enhanced technologies, which require qubits with long-lived quantum features.…”

Section: Introductionmentioning

confidence: 99%

Protecting quantum resources via frequency modulation of qubits in leaky cavities

Mortezapour

Franco

2018

Sci Rep

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Finding strategies to preserve quantum resources in open systems is nowadays a main requirement for reliable quantum-enhanced technologies. We address this issue by considering structured cavities embedding qubits driven by a control technique known as frequency modulation. We first study a single qubit in a lossy cavity to determine optimal modulation parameters and qubit-cavity coupling regime allowing a gain of four orders of magnitude concerning coherence lifetimes. We relate this behavior to the inhibition of the qubit effective decay rate rather than to stronger memory effects (non-Markovianity) of the system. We then exploit these findings in a system of noninteracting qubits embedded in separated cavities to gain basic information about scalability of the procedure. We show that the determined modulation parameters enable lifetimes of quantum resources, such as entanglement, discord and coherence, three orders of magnitude longer than their natural (uncontrolled) decay times. We discuss the feasibility of the system within the circuit-QED scenario, typically employed in the current quantum computer prototypes. These results provide new insights towards efficient experimental strategies against decoherence.

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Section: Introductionmentioning

confidence: 99%

Protecting quantum resources via frequency modulation of qubits in leaky cavities

Mortezapour

Franco

2018

Sci Rep

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“…For instances, Bellomo B et al studied the entanglement dynamics of two independent qubits in non-Markovian environments [18,19]. Xiao X et al [20] discussed the discord dynamics of two qubits in this model. In Refs [19,20,21,22], the same model is adopted, in which the whole system can be divided into two parts and a formal solution for the evolution may be obtained by exactly solving the time-dependent Schrödinger equation in the subspace with one excitation.…”

Section: Introductionmentioning

confidence: 99%

“…Xiao X et al [20] discussed the discord dynamics of two qubits in this model. In Refs [19,20,21,22], the same model is adopted, in which the whole system can be divided into two parts and a formal solution for the evolution may be obtained by exactly solving the time-dependent Schrödinger equation in the subspace with one excitation. The results show that discord is much more robust compared to entanglement in open quantum systems.…”

Section: Introductionmentioning

confidence: 99%

Discord and entanglement in non-Markovian environments at finite temperatures

Zou¹,

Mao-Fa²

2016

Chinese Phys. B

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The dynamics evolutions of discord and entanglement of two atoms in two independent Lorentzian reservoirs at zero or finite temperature have been investigated by using the time-convolutionless master-equation method. Our results show that, when both the non-Markovian effect and the detuning are present simultaneously, due to the memory and feedback effect of the non-Markovian reservoirs, the discord and the entanglement can be effectively protected even at nonzero temperature by increasing the non-Markovian effect and the detuning. The discord and the entanglement have different robustness for different initial states and their robustness may changes under certain conditions. Nonzero temperature can accelerate the decays of discord and entanglement and induce the entanglement sudden death.

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“…Recently, it has been aware of the fact that quantum discord is a more general concept to measure quantum correlation than quantum entanglement(QE) since there is a nonzero quantum discord in some separable mixed states [4]. The dynamics of quantum discord and entanglement has been recently compared under the same conditions when entanglement dynamic undergoes a sudden death [6,7,8,9,10]. It was shown that quantum discord presents an instantaneous disappearance at some time points in non-Markovian regime [6], and exponential decay in Markovian regime [7].…”

Section: Introductionmentioning

confidence: 99%

Quantum discord and its geometric measure with death entanglement in correlated dephasing two qubits system

Mohamed¹

2013

Quant. Inf. Rev.

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The quantum correlations, including entanglement and discord with its geometric measure, and classical correlation are studied for a bipartite partition of a open or closed quantum system. It is found that the purity of the initial state plays an important role in the dynamics of quantum and classical correlations. In the dephasing model, the quantum correlations loss and the classical correlation gain are instantaneously happen. While, the purity of the initial state destroys the quantum correlations which is resulted by the unitary interaction. Therefore, with the purity parameter, a particular region in which there is no state have quantum correlations can be determined.

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Quantum discord in non-Markovian environments

Cited by 24 publications

References 26 publications

Protecting quantum resources via frequency modulation of qubits in leaky cavities

Protecting quantum resources via frequency modulation of qubits in leaky cavities

Discord and entanglement in non-Markovian environments at finite temperatures

Quantum discord and its geometric measure with death entanglement in correlated dephasing two qubits system

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