Letter abstract

Nature Physics 4, 99 - 102 (2008)
Published online: 23 December 2007 | doi:10.1038/nphys885

Subject Category: Quantum physics

Evolution equation for quantum entanglement

Thomas Konrad1, Fernando de Melo2,3, Markus Tiersch2,3, Christian Kasztelan4, Adriano Aragão2,5 & Andreas Buchleitner2,3


Quantum information technology1 largely relies on a precious and fragile resource, quantum entanglement, a highly non-trivial manifestation of the coherent superposition of states of composite quantum systems. However, our knowledge of the time evolution of this resource under realistic conditions—that is, when corrupted by environment-induced decoherence—is so far limited, and general statements on entanglement dynamics in open systems are scarce2, 3, 4, 5, 6, 7, 8, 9, 10, 11. Here we prove a simple and general factorization law for quantum systems shared by two parties, which describes the time evolution of entanglement on passage of either component through an arbitrary noisy channel. The robustness of entanglement-based quantum information processing protocols is thus easily and fully characterized by a single quantity.

  1. Quantum Research Group, School of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa
  2. Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, D-01187 Dresden, Germany
  3. Albert-Ludwigs-Universität Freiburg, Physikalisches Institut, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany
  4. Institut für Theoretische Physik C, RWTH Aachen, D-52056 Aachen, Germany
  5. Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68.528, CEP 21945-970, Rio de Janeiro, RJ, Brazil

Correspondence to: Andreas Buchleitner2,3 e-mail: abu@pks.mpg.de

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