Non-Markovian entanglement dynamics of two spin-1/2 particles embedded in two separate spin star baths with tunable external magnetic fields

Xing, Xiao; Mao-Fa, Fang; Li, Y. L.; Kang, Gu‐Hyeok; Wu, Chunlin

doi:10.1140/epjd/e2010-00065-0

Cited by 7 publications

(8 citation statements)

References 37 publications

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“…N i=1 S ± i are the collective angular momentum operators of the spin-ring, in which S ± i are the corresponding operators of the ith spin in the ring, N is the number of the spins in the ring. In our model, we assume that all the spins have the value 1/2, and all the spins in the ring have the same coupling to the intermediate spin, and all the couplings among the spins in the ring are the same, as considered in Refs [9,22]. By using the Holstein-Primakoff transformation…”

Section: The Model and Hamiltonianmentioning

confidence: 99%

“…special X-structure, which is maintained during the evolution [22]. By virtue of the symmetries of such density matrix, the concurrence of the two system-spins can be simplified as C AB (t) = C (t) + C (t) [25], where…”

Section: Numerical Analysis On the Entanglement Dynamicsmentioning

confidence: 99%

“…Extensive works have been put forward to protect entanglement or coherence in spin systems [16][17][18][19][20][21][22][23]. And it has been found that strong system-environment couplings [17], low temperatures [18] and initial system-environment correlations [20] play an important role in the dynamics of spin systems.…”

Section: Introductionmentioning

confidence: 99%

“…And it has been found that strong system-environment couplings [17], low temperatures [18] and initial system-environment correlations [20] play an important role in the dynamics of spin systems. In addition, some meaningful proposals show that the dynamics of entanglement can be frozen and inhibit their relaxation into the environment by tuning the interaction parameters and the detuning [22,23].…”

Section: Introductionmentioning

confidence: 99%

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Entanglement Dynamics of Two Spins in Initially Correlated Wheel-Shaped Spin Baths

et al. 2015

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We study the effects of the initial correlations in environment on the entanglement dynamics of spin system. The correlated environment is novelly simulated by two correlated wheel-shaped spin baths, each consisting of an intermediate spin interacting with a spin-ring. The correlations in environment are achieved by the entanglement between two intermediate spins. The spin system includes two system-spins, and the interaction between the spin system and the environment is implemented by the coupling between the systemspin and the intermediate spin. Firstly, we analyze the influences of the initial entanglement between the two intermediate spins, the coupling parameters and the temperature of the baths on the entanglement dynamics of the two system-spins in equivalent subsystems. It is demonstrated that the initial entanglement between the baths can act as a resource for the generation and the revivals of the entanglement of the system-spins. Moreover, the amount of the generation and the revivals of the entanglement of the system-spins can be enhanced by regulating the coupling constants and the temperature of the baths. In addition, we also investigate the influences of different coupling ratios in non-equivalent subsystems, it is found that changing the coupling ratios of two subsystems has a significant effect on the generation and revivals of entanglement of system-spins.

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Section: The Model and Hamiltonianmentioning

confidence: 99%

Section: Numerical Analysis On the Entanglement Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Entanglement Dynamics of Two Spins in Initially Correlated Wheel-Shaped Spin Baths

et al. 2015

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“…Even a very low noise level can completely destroy the superiority of quantum metrological protocols and turn HL into SQL. However, non-Markovian environments which characterized by long correlation times or structured spectral features would be more general in many physical situations [25][26][27][28][29]. The research of nonMarkovian effects (also known as memory effects) is attracting extensive attentions due to key developments in the analysis, understanding, and even simulation of nontrivial system-environment effects [30][31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Classical-driving-enhanced parameter-estimation precision of a non-Markovian dissipative two-state system

Xing

Yao

2015

Phys. Rev. A

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The dynamics of quantum Fisher information (QFI) of the phase parameter in a driven two-state system is studied within the framework of non-Markovian dissipative process. The influences of memory effects, classical driving and detunings on the parameter-estimation precision are demonstrated by exactly solving the Hamiltonian under rotating-wave approximation. In sharp contrast with the results obtained in the presence of Markovian dissipation, we find that classical driving can drastically enhance the QFI, namely, the precision of parameter estimation in the non-Markovian regime. Moreover, the parameter-estimation precision may even be preserved from the influence of surrounding non-Markovian dissipation with the assistance of classical driving. Remarkably, we reveal that the enhancement and preservation of QFI highly depend on the combination of classical driving and non-Markovian effects. Finally, a phenomenological explanation of the underlying mechanism is presented in detail via the quasimode theory.

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Protecting the squeezing of a two-level system by detuning in non-Markovian environments

Xing

Mao-Fa

2011

Phys. Scr.

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Squeezing of a two-level atom off-resonantly coupled to a non-Markovian reservoir is investigated. We compared two different definitions of squeezing that are based on the Heisenberg uncertainty relation and the entropy uncertainty relation and found that information entropy squeezing is more precise than variance squeezing as a measure of squeezing. Then we utilized entropy squeezing to examine the influences of the non-Markovian effect and detuning on the atomic squeezing. It is interesting to note that atomic squeezing can be protected for a long time when both the non-Markovian effect and detuning are present simultaneously. The physical mechanism is that the decay rate is suppressed much more by detuning in the non-Markovian regime than in the Markovian case.

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Non-Markovian entanglement dynamics of two spin-1/2 particles embedded in two separate spin star baths with tunable external magnetic fields

Cited by 7 publications

References 37 publications

Entanglement Dynamics of Two Spins in Initially Correlated Wheel-Shaped Spin Baths

Entanglement Dynamics of Two Spins in Initially Correlated Wheel-Shaped Spin Baths

Classical-driving-enhanced parameter-estimation precision of a non-Markovian dissipative two-state system

Protecting the squeezing of a two-level system by detuning in non-Markovian environments

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