skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Three-qubit thermal entanglement via entanglement swapping on two-qubit Heisenberg XY chains

Abstract

In this paper, we consider the generation of a three-qubit Greenberger-Horne-Zeilinger-like thermal state by applying the entanglement swapping scheme of Zukowski et al. [Ann. N. Y. Acad. Sci. 755, 91 (1995)] to three pairs of two-qubit Heisenberg XY chains. The quality of the resulting three-qubit entanglement is studied by analyzing the teleportation fidelity, when it is used as a resource in the teleportation protocol of Karlsson et al. [Phys. Rev. A 58, 4394 (1998)]. We show that even though thermal noise in the original two-qubit states is amplified by the entanglement swapping process, we are still able to achieve nonclassical fidelities for the anisotropic Heisenberg XY chains at finitely higher and higher temperatures by adjusting the strengths of an external magnetic field. This has a positive implication on the solid-state realization of a quantum computer.

Authors:
; ;  [1];  [2]
  1. Hwa Chong Institution, 673 Bukit Timah Road, Singapore 269735 (Singapore)
  2. (Singapore)
Publication Date:
OSTI Identifier:
20786265
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 72; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevA.72.062302; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; HEISENBERG MODEL; MAGNETIC FIELDS; NOISE; QUANTUM COMPUTERS; QUANTUM ENTANGLEMENT; QUANTUM TELEPORTATION; QUBITS; SOLIDS

Citation Formats

Kao, Zi Chong, Ng, Jezreel, Yeo, Ye, and Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. Three-qubit thermal entanglement via entanglement swapping on two-qubit Heisenberg XY chains. United States: N. p., 2005. Web. doi:10.1103/PHYSREVA.72.0.
Kao, Zi Chong, Ng, Jezreel, Yeo, Ye, & Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. Three-qubit thermal entanglement via entanglement swapping on two-qubit Heisenberg XY chains. United States. doi:10.1103/PHYSREVA.72.0.
Kao, Zi Chong, Ng, Jezreel, Yeo, Ye, and Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. Thu . "Three-qubit thermal entanglement via entanglement swapping on two-qubit Heisenberg XY chains". United States. doi:10.1103/PHYSREVA.72.0.
@article{osti_20786265,
title = {Three-qubit thermal entanglement via entanglement swapping on two-qubit Heisenberg XY chains},
author = {Kao, Zi Chong and Ng, Jezreel and Yeo, Ye and Department of Physics, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260},
abstractNote = {In this paper, we consider the generation of a three-qubit Greenberger-Horne-Zeilinger-like thermal state by applying the entanglement swapping scheme of Zukowski et al. [Ann. N. Y. Acad. Sci. 755, 91 (1995)] to three pairs of two-qubit Heisenberg XY chains. The quality of the resulting three-qubit entanglement is studied by analyzing the teleportation fidelity, when it is used as a resource in the teleportation protocol of Karlsson et al. [Phys. Rev. A 58, 4394 (1998)]. We show that even though thermal noise in the original two-qubit states is amplified by the entanglement swapping process, we are still able to achieve nonclassical fidelities for the anisotropic Heisenberg XY chains at finitely higher and higher temperatures by adjusting the strengths of an external magnetic field. This has a positive implication on the solid-state realization of a quantum computer.},
doi = {10.1103/PHYSREVA.72.0},
journal = {Physical Review. A},
number = 6,
volume = 72,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • We investigate the thermal entanglement in the two-qubit Heisenberg XY model with a nonuniform magnetic field. Concurrence, the measurement of entanglement, is calculated. The behavior of concurrence is present at three different cases. Contrary to the uniform magnetic field case, we find that the entanglement and the critical temperature T{sub C} may be enhanced under a nonuniform magnetic field.
  • In this work, we investigate the problem of a secretly broadcasting of a three-qubit entangled state between two distant partners. The interesting feature of this problem is that starting from two-particle entangle states shared between two distant partners we find that the action of a local cloner on the qubits and the measurement on the machine state vector generates three-qubit entanglement between them. The broadcasting of entanglement is made secret by sending the measurement result secretly using cryptographic scheme based on orthogonal states. Further we show that this idea can be extended to generate three-particle entangled states between three distantmore » partners.« less
  • The thermal entanglement in a two-qubit Heisenberg XXZ spin chain is investigated under an inhomogeneous magnetic field b. We show that the ground-state entanglement is independent of the interaction of z-component J{sub z}. The thermal entanglement at the fixed temperature can be enhanced when J{sub z} increases. We strictly show that for any temperature T and J{sub z}, the entanglement is symmetric with respect to zero inhomogeneous magnetic field, and the critical inhomogeneous magnetic field b{sub c} is independent of J{sub z}. The critical magnetic field B{sub c} increases with the increasing |b| but the maximum entanglement value that themore » system can arrive at becomes smaller.« less
  • Thermal entanglement of a two-qubit Heisenberg chain in the presence of the Dzyaloshinski-Moriya (DM) anisotropic antisymmetric interaction and entanglement teleportation when using two independent Heisenberg chains as the quantum channel are investigated. It is found that the DM interaction can excite entanglement and teleportation fidelity. The output entanglement increases linearly with increasing value of the input; its dependences on the temperature, DM interaction, and spin coupling constant are given in detail. Entanglement teleportation will be better realized via an antiferromagnetic spin chain when the DM interaction is turned off and the temperature is low. However, the introduction of the DMmore » interaction can cause the ferromagnetic spin chain to be a better quantum channel for teleportation. A minimal entanglement of the thermal state in the model is needed to realize the entanglement teleportation regardless of whether the spin chains are antiferromagnetic or ferromagnetic.« less
  • We study the dynamics of entanglement in a two-qubit system interacting with a squeezed thermal bath via a dissipative system-reservoir interaction with the system and reservoir assumed to be in a separable initial state. The resulting entanglement is studied by making use of concurrence as well as a recently introduced measure of mixed state entanglement via a probability density function which gives a statistical and geometrical characterization of entanglement by exploring the entanglement content in the various subspaces spanning the two-qubit Hilbert space. We also make an application of the two-qubit dissipative dynamics to a simplified model of quantum repeaters.