Subdecoherent Information Encoding in a Quantum-Dot Array

Abstract

A potential implementation of quantum-information schemes in semiconductor nanostructures is studied. To this end, the formal theory of quantum encoding for avoiding errors is recalled and the existence of noiseless states for model systems is discussed. Based on this theoretical framework, we analyze the possibility of designing noiseless quantum codes in realistic semiconductor structures. In the specific implementation considered, information is encoded in the lowest energy sector of charge excitations of a linear array of quantum dots. The decoherence channel considered is electron-phonon coupling We show that besides the well-known phonon bottleneck, reducing single-qubit decoherence, suitable many-qubit initial preparation as well as register design may enhance the decoherence time by several orders of magnitude. This behaviour stems from the effective one-dimensional character of the phononic environment in the relevant region of physical parameters.

12 pages LaTeX, 5 postscript figures. Final version accepted by PRB

References in corpus (6)

• Quantum Computation with Quantum Dots
• Noiseless Quantum Codes
• Quantum Information in Semiconductors: Noiseless Encoding in a Quantum-Dot Array
• Error Avoiding Quantum Codes
• Dissipation and Decoherence in a Quantum Register
• Addition energies in semiconductor quantum dots: Role of electron-electron interaction

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