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HAIT Journal of Science and Engineering A Volume 5, Issues 1-2, pp. 112-139 © 2008 Holon Institute of Technology | |||
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Quantitative evaluation of decoherence and applications for quantum-dot charge qubits
Leonid Fedichkin and Vladimir Privman*
Center for Quantum Device Technology, | Department of Physics and Department of Electrical and Computer Engineering, Clarkson University, Potsdam, New York 13699--5721, USA *Corresponding author: privman@clarkson.edu Received 12 September 2007
| We review results on evaluation of loss of information in quantum registers due to their interactions with the environment. It is demonstrated that an optimal measure of the level of quantum noise effects can be introduced via the maximal absolute eigenvalue norm of deviation of the density matrix of a quantum register from that of ideal, noiseless dynamics. For a semiconductor quantum dot charge qubits interacting with acoustic phonons, explicit expressions for this measure are derived. For a broad class of environmental modes, this measure is shown to have the property that for small levels of quantum noise it is additive and scales linearly with the size of the quantum register. PACS: 03.65.Yz, 85.35.Be, 03.67.Lx, 63.20.Kr |