Trade-off between Squashed Entanglement and Concurrence in Bipartite Quantum States

TL;DR

This paper explores how squashed entanglement and concurrence evolve under different Hamiltonians in Werner and MEMS states, revealing trade-offs, sudden death phenomena, and robustness of entanglement measures.

Contribution

It provides a comparative analysis of entanglement dynamics under Heisenberg and bi-linear bi-quadratic Hamiltonians, highlighting the robustness of certain entanglement measures.

Findings

Entanglement sudden death observed in Werner state with Heisenberg Hamiltonian.

Bi-linear bi-quadratic Hamiltonian does not disturb entanglement measures.

Robustness of squashed entanglement and concurrence under specific Hamiltonian dynamics.

Abstract

In this article we investigate the unitary dynamics of squashed entanglement and concurrence measures in Werner state and maximally entangled mixed states (MEMS) under two different Hamiltonians. The aim of the present study is two fold. The first part of the study deals with the dynamics under Heisenberg Hamiltonian and the second part deals under bi-linear bi-quadratic Hamiltonian which is the extension of first Hamiltonian. In both the parts we investigate the dynamical trade off and balancing points for squashed entanglement and concurrence. During the study, we also found the results of entanglement sudden death (ESD) with Heisenberg Hamiltonian in Werner state under concurrence measure. In second part, we investigate the special result for bi-linear bi-quadratic Hamiltonian; it does not disturb squashed entanglement and concurrence in both the states and exhibit the robust character for both of the states.