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arXiv:2302.10192

Tridiagonal Toeplitz Matrices and Bipartite Quantum Correlations

Varsha Sambhaje, Suprabhat Sinha, Sharma, Kapil K.

Published Feb 18, 2023• 0 citations
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Abstract

In this article, we focus on tridiagonal Toeplitz Hermitian matrices, which fulfill the requirement of a valid Hamiltonian often used in Quantum Information. We investigate the behavior of such matrices to pursue the dynamics of quantum correlations (entanglement and quantum discord) for bipartite Werner state and maximally entangled mixed states. We have found interesting results that the main diagonal terms in the Toeplitz matrices never affect the quantum correlations in both quantum states. However, super-diagonal and sub-diagonal terms play the important role in the dynamics. We investigate the phenomenon of entanglement sudden death and also observe the presence of quantum discord in the absence of entanglement. Most importantly it is found that MEMS is more sensitive in comparison to the Werner state.

DOI
10.48550/arxiv.2302.10192

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In this article, we focus on tridiagonal Toeplitz Hermitian matrices, which fulfill the requirement of a valid Hamiltonian often used in Quantum Information. We investigate the behavior of such matrices to pursue the dynamics of quantum correlations (entanglement and quantum discord) for bipartite Werner state and maximally entangled mixed states. We have found interesting results that the main diagonal terms in the Toeplitz matrices never affect the quantum correlations in both quantum states. However, super-diagonal and sub-diagonal terms play the important role in the dynamics. We investigate the phenomenon of entanglement sudden death and also observe the presence of quantum discord in the absence of entanglement. Most importantly it is found that MEMS is more sensitive in comparison to the Werner state.
Comparison of quantum discord and fully entangled fraction of two classes of d⊗d2d\otimes d^2d⊗d2 states
The quantumness of a generic state is the resource of many applications in quantum information theory and it is interesting to survey the measures which are able to detect its trace in the properties of the state. In this work we study the quantum discord and fully entangled fraction of two classes of bipartite states and compare their behaviors. These classes are complements to the d⊗dd\otimes dd⊗d Werner and isotropic states, in the sense that each class possesses the same purification as the corresponding complemental class of states. Our results show that maximally entangled mixed states are also maximally discordant states, leading to a generalization of the well-known fact that all maximally entangled pure states have also maximum quantum discord. Moreover, it is shown that the separability-entanglement boundary of a Werner or isotropic state is manifested as an inflection point in the diagram of quantum discord of the corresponding complemental state.
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