Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/599

Title

Decoherence rates in large-scale quantum computers and macroscopic quantum systems

Author(s)

Dalton, B. J.

Abstract

Markovian regime decoherence effects in quantum computers are studied in terms of the fidelity for the situation where the number of qubits N becomes large. A general expression giving the decoherence time scale in terms of Markovian relaxation elements and expectation values of products of system fluctuation operators is obtained, which could also be applied to study decoherence in other macroscopic systems such as Bose condensates and superconductors. A standard circuit model quantum computer involving three-state lambda system ionic qubits is considered, with qubits localized around well-separated positions via trapping potentials. The centre of mass vibrations of the qubits act as a reservoir. Coherent one and two qubit gating processes are controlled by time-dependent localized classical electromagnetic fields that address specific qubits, the two qubit gating processes being facilitated by a cavity mode ancilla, which permits state interchange between qubits. With a suitable choice of parameters, it is found that the decoherence time can be made essentially independent of N.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Engineering and Industrial Sciences. Centre for Atom Optics and Ultrafast Spectroscopy

Source

Journal of Modern Optics, Vol. 52, no. 17 (2005), pp. 2563-2587

Publication year

2005

Publisher

Taylor and Francis

ISSN

0950-0340

Publisher URL

http://dx.doi.org/10.1080/09500340500227695

Copyright

© 2005 Taylor & Francis

Peer reviewed