Thermal entanglement witness for materials with variable local spin lengths

Souza, André M. C.; Almeida, Francisco A. G.

doi:10.1103/physreva.79.052337

Cited by 16 publications

(20 citation statements)

References 37 publications

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“…It has been shown that magnetic susceptibility can be an entanglement witness [27][28][29], which is used to point out the presence of entanglement. Also momentum-momentum correlation [30,31], energies [21,22], and probability density at highly symmetric points [22] have been proposed as entanglement indicators, which reproduce the general trend of entanglement.…”

Section: Introductionmentioning

confidence: 99%

Entanglement from density measurements: Analytical density functional for the entanglement of strongly correlated fermions

França

D’Amico²

2011

Phys. Rev. A

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We derive an analytical density functional for the single-site entanglement of the one-dimensional homogeneous Hubbard model by means of an approximation to the linear entropy. We show that this very simple density functional reproduces quantitatively the exact results. We then use this functional as input for a local-density approximation to the single-site entanglement of inhomogeneous systems. We illustrate the power of this approach in a harmonically confined system, which could simulate recent experiments with ultracold atoms in optical lattices as well as in a superlattice and in an impurity system. The impressive quantitative agreement with numerical calculations-which includes reproducing subtle signatures of the particle density stages-shows that our density functional can provide entanglement calculations for actual experiments via density measurements. Next we use our functional to calculate the entanglement in disordered systems. We find that, in contrast with the expectation that disorder destroys the entanglement, there exist regimes for which the entanglement remains almost unaffected by the presence of disordered impurities.

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Section: Introductionmentioning

confidence: 99%

Entanglement from density measurements: Analytical density functional for the entanglement of strongly correlated fermions

França

D’Amico²

2011

Phys. Rev. A

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“…It is worthwhile to apply the NES to the Hubbard model [54], which is a typical model for strongly correlated fermion systems and which has been widely adopted for a study on quantum information [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Despite the simplicity of the model, however, it is very difficult to obtain its exact solution except for some limited cases.…”

Section: Introductionmentioning

confidence: 99%

“…Small-scale systems belong to nonextensive systems as mentioned above. It is necessary to take into account the effect of nonextensivity, when we study the properties of quantum information of qubits, which have been mainly investigated within the BGS [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. In recent years, the NES has been applied to the study on quantum information [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53].…”

Section: Introductionmentioning

confidence: 99%

“…Quantum entanglement is expected to play an essential role as a resource in quantum communication and information processing. Many studies have been made on quantum entanglement with quantum spin models [3][4][5][6][7][8][9][10][11] and fermion systems [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] to clarify both its qualitative and quantitative aspects. The interface between the quantum information and statistical mechanics has been considerably investigated in recent years.…”

Section: Introductionmentioning

confidence: 99%

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Thermal entanglement of Hubbard dimers in the nonextensive statistics

Hasegawa¹

2011

Physica A: Statistical Mechanics and its Applications

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The thermal entanglement of the Hubbard dimer (two-site Hubbard model) has been studied with the nonextensive statistics. We have calculated the auto-correlation ($O_q$), pair correlation ($L_q$), concurrence ($\Gamma_q$) and conditional entropy ($R_q$) as functions of entropic index $q$ and the temperature $T$. The thermal entanglement is shown to considerably depend on the entropic index. For $q < 1.0$, the threshold temperature where $\Gamma_q$ vanishes or $R_q$ changes its sign is more increased and the entanglement may survive at higher temperatures than for $q=1.0$. Relations among $L_q$, $\Gamma_q$ and $R_q$ are investigated. The physical meaning of the entropic index $q$ is discussed with the microcanonical and superstatistical approaches. The nonextensive statistics is applied also to Heisenberg dimers.Comment: 28 pages, 6 figures; the final version accepted in Physica

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“…The development of criteria for the detection of entanglement based on the violation of appropriate uncertainty relations has been the focus of some interesting recent investigations [18][19][20][21][22][23]. One can establish uncertainty relations that are satisfied by all separable (pure or mixed) states and, consequently, any violation of these relations indicates that the quantum state under consideration is entangled.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty relations and entanglement in fermion systems

Zander

Plastino

2010

Phys. Rev. A

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The violation of uncertainty relations is used as a signature of entanglement for both pure and mixed states of two identical fermions. In the case of fermions with a four dimensional single particle Hilbert space we obtain several different types of uncertainty-related entanglement criteria based on local uncertainty relations, on the sum of variances of projectors, and on various entropic measures. Within the latter approach we consider either entropic uncertainty relations involving a single observable or relations based upon the sum of entropies associated with more than one observable. We extend the projector based entanglement criterion to the case of two-fermion and three-fermion systems with a six dimensional single particle Hilbert space.

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Thermal entanglement witness for materials with variable local spin lengths

Cited by 16 publications

References 37 publications

Entanglement from density measurements: Analytical density functional for the entanglement of strongly correlated fermions

Entanglement from density measurements: Analytical density functional for the entanglement of strongly correlated fermions

Thermal entanglement of Hubbard dimers in the nonextensive statistics

Uncertainty relations and entanglement in fermion systems

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