Decoherence and Programmable Quantum Computation

Abstract

An examination of the concept of using classical degrees of freedom to drive the evolution of quantum computers is given. Specifically, when externally generated, coherent states of the electromagnetic field are used to drive transitions within the qubit system, a decoherence results due to the back reaction from the qubits onto the quantum field. We derive an expression for the decoherence rate for two cases, that of the single-qubit Walsh-Hadamard transform, and for an implementation of the controlled-NOT gate. We examine the impact of this decoherence mechanism on Grover's search algorithm, and on the proposals for use of error-correcting codes in quantum computation.

submitted to Phys. Rev. A 35 double-spaced pages, 2 figures, in LaTeX

References in corpus (3)

• Quantum Mechanics helps in searching for a needle in a haystack
• Nuclear magnetic resonance spectroscopy: An experimentally accessible paradigm for quantum computing
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• Quantum error correction failure distributions: comparison of coherent and stochastic error models
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• Gate fidelity of arbitrary single-qubit gates constrained by conservation laws
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• Conservation-Law-Induced Quantum Limits for Physical Realizations of the Quantum NOT Gate
• Reply to "Comment on "Some implications of the quantum nature of laser fields for quantum computations''''
• Minimum-energy pulses for quantum logic cannot be shared
• Qualitative aspects of entanglement in the Jaynes-Cummings model with an external quantum field
• Comparing the quantum switch and its simulations with energetically-constrained operations
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• Grover's algorithm on a Feynman computer
• Quantum Limits of Measurements Induced by Multiplicative Conservation Laws: Extension of the Wigner-Araki-Yanase Theorem
• Invariance of success probability in Grover's quantum search under local noise with memory