Local quantum uncertainty in two-qubit separable states: a case study

Sen, Asim K.; Sarkar, Debasis; Bhar, Amit

doi:10.1007/s11128-015-1114-x

Cited by 20 publications

(3 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Theory suggests that the LQU as a reliable quantifier of quantum correlations in bipartite quantum systems satisfies all the physical requirements of a measure of quantum correlations [10]. Due to the importance of the LQU as a fundamental concept, there are a large list of references dedicated to the dynamics of quantum correlations described by LQU in various bipartite or multiple systems subject to different environments [11][12][13][14][15][16][17][18][19][20]. At the same time, there also exists another important subject on LQU to explore various applications as well as its relationship with quantum metrology where the LQU provides a guaranteed upper bound to the variance of estimator in parameter estimation protocol [21,22].…”

Section: Introductionmentioning

confidence: 99%

Local quantum uncertainty in a two-qubit Heisenberg spin chain with intrinsic decoherence

Guo¹,

Peng²,

Tian³

et al. 2021

Phys. Scr.

View full text Add to dashboard Cite

Quantum correlation plays an important role in quantum information processing, for which various quantifiers have been proposed so far. In this paper, we address the dynamics of local quantum uncertainty (LQU) as a reliable quantifier of quantum correlation in a two-qubit Heisenberg spin chain in the presence of nonuniform external magnetic field and Dzyaloshinski-Moriya interaction with intrinsic decoherence. The influences of the initial states, external magnetic field strength, Dzyaloshinski-Moriya interaction strength and intrinsic decoherence rate on the dynamics of LQU have been in detail investigated. Our analytical results show that the dynamics of LQU is strongly depended on the form of initial states. For an initial correlated state, the dynamical behaviors of LQU exhibit either monotonic decay or damped oscillations with respect to time. While for an initial separable state, quantum correlation quantified by LQU can be created due to the Dzyaloshinski-Moriya interaction and Heisenberg anisotropic interaction. Besides, the relationship between LQU and l-norm coherence or concurrence is also demonstrated in the present model.

show abstract

Section: Introductionmentioning

confidence: 99%

Local quantum uncertainty in a two-qubit Heisenberg spin chain with intrinsic decoherence

Guo¹,

Peng²,

Tian³

et al. 2021

Phys. Scr.

View full text Add to dashboard Cite

show abstract

“…Recently, it has been proved that LQU meets the criteria for a discord-like quantifier of quantum correlations. The LQU approach has been used as a reliable measure to characterize nonclassical correlations in a few frameworks [39][40][41][42][43][44] The general motivation for studying coherence and quantum correlations in light-harvesting structures is that the precise characterization of these quantum resources is essential, on the one hand, for understanding their functional relation with the energy transfer mechanism and, on ther other, to be able to construct naturally robust quantum devices based on that mechanics. Our principal aim is to demonstrate that the Local Quantum Uncertainty is a highly flexible, robust, and consistent metric to characterize quantum correlations, which is and a novel approach that had not been studied before.…”

Section: Introductionmentioning

confidence: 99%

Local quantum uncertainty as a robust metric to characterize discord-like quantum correlations in subsets of the chromophores in photosynthetic light-harvesting complexes

Chávez-Huerta

Rojas

2020

Rev. Mex. Fís.

View full text Add to dashboard Cite

Green sulfur bacteria is a photosynthetic organism whose light-harvesting complex accommodates a pigment-protein complex called Fenna-Matthews-Olson (FMO). The FMO complex sustains quantum coherence and quantum correlations between the electronic states of spatially separated pigment molecules as energy moves with nearly a 100% quantum efficiency to the reaction center. We present a method based on the quantum uncertainty associated to local measurements to quantify discord-like quantum correlations between two subsystems where one is a qubit and the other is a qudit. We implement the method by calculating local quantum uncertainty (LQU), concurrence, and coherence between subsystems of pure and mixed states represented by the eigenstates and by the thermal equilibrium state determined by the FMO Hamiltonian. Three partitions of the seven chromophores network define the subsystems: one chromophore with six chromophores, pairs of chromophores, and one chromophore with two chromophores. Implementation of the LQU approach allows us to characterize quantum correlations that had not been studied before, identify the most quantum correlated subsets of chromophores, and determine that, in the strongest associations of chromophores, the LQU is a monotonically increasing function of the coherence.

show abstract

“…Compare to quantum discord, LQU is easy to calculate. Therefore, study on LQU including its dynamical behavior in various noisy environments has intensively investigated [24][25][26][27][28][29][30]. For example, the LQU dynamical behavior as a indicator of quantum criticality in multipartite spin systems has been studied [31,32].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of local quantum uncertainty for a two-qubit system under dephasing noise

et al. 2019

View full text Add to dashboard Cite

Recently, local quantum uncertainty (LQU) as a measure of quantum correlations has been proposed by Girolami et al. We here have investigated the LQU dynamics in a pair of qubits system subjected to either local or collective classical phase noises. The explicit analytical expressions of LQU for the two-qubit system of interest initially in a Werner state under these dephasing noises have been derived. We compare the dynamics of LQU with that of entanglement as measured with concurrence. Our results show that LQU always decays asymptotically while the entanglement displays sudden death phenomenon. Besides, there is no simple relation between the LQU and entanglement since LQU may be smaller or larger than entanglement. Finally, we try to protect LQU against the dephasing noise by means of filtering operation.

show abstract

Local quantum uncertainty in two-qubit separable states: a case study

Cited by 20 publications

References 42 publications

Local quantum uncertainty in a two-qubit Heisenberg spin chain with intrinsic decoherence

Local quantum uncertainty in a two-qubit Heisenberg spin chain with intrinsic decoherence

Local quantum uncertainty as a robust metric to characterize discord-like quantum correlations in subsets of the chromophores in photosynthetic light-harvesting complexes

Dynamics of local quantum uncertainty for a two-qubit system under dephasing noise

Contact Info

Product

Resources

About