Condensed Matter Theory   Universität Basel
Dr. Jörg Lehmann

Highly Entangled Ground States in Tripartite Qubit Systems

B. Röthlisberger, J. Lehmann, D. S. Saraga, P. Traber, and D. Loss

Phys. Rev. Lett. 100, 100502 (2008)

Preprint: arXiv:0705.1710

We investigate the creation of highly entangled ground states in a system of three exchange-coupled qubits arranged in a ring geometry. Suitable magnetic field configurations yielding approximate GHZ and exact W ground states are identified. The entanglement in the system is studied at finite temperature in terms of the mixed-state tangle tau. By adapting a steepest-descent optimization algorithm we demonstrate that tau can be evaluated efficiently and with high precision. We identify the parameter regime for which the equilibrium entanglement of the tripartite system reaches its maximum.

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Uni Basel » Department of Physics » Condensed Matter Theory
last updated on 2008/03/19