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Phys. Rev. A 78, 042307 (2008) [9 pages]

Preparation of entangled states by quantum Markov processes

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B. Kraus1, H. P. Büchler2, S. Diehl1,3, A. Kantian1,3, A. Micheli1,3, and P. Zoller1,3
1Institute for Theoretical Physics, University of Innsbruck, Innsbruck, Austria
2Institute for Theoretical Physics III, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
3Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Innsbruck, Austria

Received 1 April 2008; published 8 October 2008

We investigate the possibility of using a dissipative process to prepare a quantum system in a desired state. We derive for any multipartite pure state a dissipative process for which this state is the unique stationary state and solve the corresponding master equation analytically. For certain states, such as the cluster states, we use this process to show that the jump operators can be chosen quasilocally, i.e. they act nontrivially only on a few, neighboring qubits. Furthermore, the relaxation time of this dissipative process is independent of the number of subsystems. We demonstrate the general formalism by considering arbitrary matrix-product states or projected entangled pair states. In particular, we show that the ground state of the Affleck-Kennedy-Lieb-Tasaki model can be prepared employing a quasi-local dissipative process.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.78.042307
DOI:
10.1103/PhysRevA.78.042307
PACS:
03.67.Bg, 42.50.−p