Scaling of decoherence effects in quantum computers

Dalton, B. J. (2003) Scaling of decoherence effects in quantum computers. Journal of Modern Optics, 50 6-7: 951-966. doi:10.1080/0950034031000064870


Author Dalton, B. J.
Title Scaling of decoherence effects in quantum computers
Journal name Journal of Modern Optics   Check publisher's open access policy
ISSN 0950-0340
Publication date 2003
Sub-type Article (original research)
DOI 10.1080/0950034031000064870
Volume 50
Issue 6-7
Start page 951
End page 966
Total pages 16
Place of publication [England]
Publisher Taylor & Francis
Collection year 2003
Language eng
Subject C1
240201 Theoretical Physics
780102 Physical sciences
0205 Optical Physics
0206 Quantum Physics
Abstract The scaling of decoherence rates with qubit number N is studied for a simple model of a quantum computer in the situation where N is large. The two state qubits are localized around well-separated positions via trapping potentials and vibrational centre of mass motion of the qubits occurs. Coherent one and two qubit gating processes are controlled by external classical fields and facilitated by a cavity mode ancilla. Decoherence due to qubit coupling to a bath of spontaneous modes, cavity decay modes and to the vibrational modes is treated. A non-Markovian treatment of the short time behaviour of the fidelity is presented, and expressions for the characteristic decoherence time scales obtained for the case where the qubit/cavity mode ancilla is in a pure state and the baths are in thermal states. Specific results are given for the case where the cavity mode is in the vacuum state and gating processes are absent and the qubits are in (a) the Hadamard state (b) the GHZ state.
Keyword Optics
Trapped Ions
Dissipation
Computation
States
Motion
Atoms
Logic
Time
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2004 Higher Education Research Data Collection
Centre for Advanced Imaging Publications
 
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Created: Wed, 15 Aug 2007, 01:58:42 EST