APS » PROLA » Phys. Rev. A » Volume 71 » Issue 2
< Previous article | Next article >

Phys. Rev. A 71, 022302 (2005) [22 pages]

Control of decoherence: Analysis and comparison of three different strategies

Download: PDF (723 kB) or Buy this Article (Use Article Pack) Export: BibTeX or EndNote (RIS)

P. Facchi1, S. Tasaki2, S. Pascazio1, H. Nakazato3, A. Tokuse2, and D. A. Lidar4
1Dipartimento di Fisica, Università di Bari and Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari, Italy
2Department of Applied Physics and Advanced Institute for Complex Systems, Waseda University, Tokyo 169-8555, Japan
3Department of Physics, Waseda University, Tokyo 169-8555, Japan
4Chemical Physics Theory Group, Chemistry Department and Center for Quantum Information and Quantum Control, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6

Received 29 March 2004; revised 23 June 2004; published 8 February 2005

We analyze and compare three different strategies, all aimed at controlling and eventually halting decoherence. The first strategy hinges upon the quantum Zeno effect, the second makes use of frequent unitary interruptions (“bang-bang” pulses and their generalization, quantum dynamical decoupling), and the third uses a strong, continuous coupling. Decoherence is shown to be suppressed only if the frequency N of the measurements or pulses is large enough or if the coupling K is sufficiently strong. Otherwise, if N or K is large, but not extremely large, all these control procedures accelerate decoherence. We investigate the problem in a general setting and then consider some practical examples, relevant for quantum computation.


©2005 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevA.71.022302
DOI: 10.1103/PhysRevA.71.022302
PACS: 03.67.Pp, 03.65.Xp, 03.65.Yz, 03.67.Lx

[ Abstract  |  Previous article  |  Next article  |  Issue 2 ]