Dynamical pairwise entanglement and two-point correlations in the three-ligand spin-star structure

Motamedifar, Mostafa

doi:10.1016/j.physa.2017.04.007

Cited by 11 publications

(4 citation statements)

References 68 publications

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“…Above all, the generation of W states is the primary condition of such captivating applications. From dynamical point of view, the quantum W states can be generated via evolution of an initial quantum state either in a spin chain [10] or in a spin star network [18]. It may be interesting that, opposing to spin chains through which W states can be dynamically created by four qubits at the most [10], star networks have shown that such states can be generated by the same number of qubits at least [18].…”

Section: Introductionmentioning

confidence: 99%

Exact dynamics of concurrence-based entanglement in a system of four spin-1/2 particles on a triangular ladder structure

2019

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Motivated by the ability of triangular spin ladders to implement quantum information processing, we propose a type of such systems whose Hamiltonian includes the XX Heisenberg interaction on the rungs and Dzyaloshinskii–Moriya (DM) coupling over the legs. In this work, we discuss how tuning the magnetic interactions between elements of a nanomagnetic cell which contains four qubits influences on the dynamical behavior of entanglement shared between any pairs of the system. In this work, we make use of concurrence for monitoring entanglement. It is realized that the generation of quantum W states is an important feature of the present model when the system evolves unitarily with time. In general, coincidence with the emergence of W states, the concurrences of all pairs are equal to 2/N, where N is the number of system’s qubits. We also obtain the precise relationship between the incidence of such states and the value of DM interaction as well as the time of entanglement transfer. Finally, by studying the two-point quantum correlations and expectation values of different spin variables, we find that xx and yy correlations bring the entanglement to a maximum value for W states, whereas for these states, zz correlation between any pairs completely quenches. Our results reveal that although does not commute with the system’s Hamiltonian, its expectation value remains constant during time evolution which is a generic property of quantum W states.

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Section: Introductionmentioning

confidence: 99%

Exact dynamics of concurrence-based entanglement in a system of four spin-1/2 particles on a triangular ladder structure

2019

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“…It is worthwhile to remark, moreover, that the quantum Heisenberg spin star is not just a theoretical curiosity without any connection to a real-world system, but it has a variety of experimental realizations in tetranuclear molecular complexes such as CrNi

[ 17 , 18 ], CrMn

[ 19 ], Cu

, Ni

and NiCu

[ 20 ]. From the perspective of quantum entanglement, only static and dynamic pairwise entanglement, two-point correlations and quantum discord of the spin-1/2 Heisenberg star with the exchange and Dzyaloshinskii–Moriya anisotropies were explored in detail in zero magnetic field and the absence of the exchange interaction between the peripheral spins [ 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Distribution of Bipartite and Tripartite Entanglement within a Spin-1/2 Heisenberg Star in a Magnetic Field

Karľová

Strečka

2023

Molecules

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The spatial distribution of entanglement within a spin-1/2 Heisenberg star composed from a single central spin and three peripheral spins is examined in the presence of an external magnetic field using the Kambe projection method, which allows an exact calculation of the bipartite and tripartite negativity serving as a measure of the bipartite and tripartite entanglement. Apart from a fully separable polarized ground state emergent at high-enough magnetic fields, the spin-1/2 Heisenberg star exhibits at lower magnetic fields three outstanding nonseparable ground states. The first quantum ground state exhibits the bipartite and tripartite entanglement over all possible decompositions of the spin star into any pair or triad of spins, whereby the bipartite and tripartite entanglement between the central and peripheral spins dominates over that between the peripheral spins. The second quantum ground state has a remarkably strong tripartite entanglement between any triad of spins in spite of the lack of bipartite entanglement. The central spin of the spin star is separable from the remaining three peripheral spins within the third quantum ground state, where the peripheral spins are subject to the strongest tripartite entanglement arising from a two-fold degenerate W-state.

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Section: Introductionmentioning

confidence: 99%

Exact dynamics of concurrence-based entanglement in a system of four spin-1/2 particles on a triangular ladder structure

Shahsavari,

Motamedifar,

Safari

2020

Preprint

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Motivated by the ability of triangular spin ladders to implement quantum information processing, we propose a type of such systems whose Hamiltonian includes the XX Heisenberg interaction on the rungs and DzyaloshinskiiMoriya (DM) coupling over the legs. In this work, we discuss how tuning the magnetic interactions between elements of a nanomagnetic cell of a triangular ladder which contains four qubits influences on the dynamical behavior of entanglement shared between any pairs of the system. In this work, we make use of concurrence for monitoring entanglement. It is realized that the generation of quantum W states is an important feature of the present model when the system evolves unitarily with time. In general, coincidence with the emergence of W states, the concurrences of all pairs are equal to 2/N , where N is the number of system's qubits. We also obtain the precise relationship between the incidence of such states and the value of DM interaction as well as the time of entanglement transfer. Finally, by studying the two-point quantum correlations and expectation values of different spin variables, we find that xx and yy correlations bring the entanglement to a maximum value for W states, whereas for these states, zz correlation between any pairs completely quenches. Our results reveal that although Ŝz tot does not commute with the system's Hamiltonian, its expectation value remains constant during time evolution which is a generic property of quantum W states.

show abstract

Dynamical pairwise entanglement and two-point correlations in the three-ligand spin-star structure

Cited by 11 publications

References 68 publications

Exact dynamics of concurrence-based entanglement in a system of four spin-1/2 particles on a triangular ladder structure

Exact dynamics of concurrence-based entanglement in a system of four spin-1/2 particles on a triangular ladder structure

Distribution of Bipartite and Tripartite Entanglement within a Spin-1/2 Heisenberg Star in a Magnetic Field

Exact dynamics of concurrence-based entanglement in a system of four spin-1/2 particles on a triangular ladder structure

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