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arXiv:0708.4101 · Journal of Physics Condensed Matter

General quantum phase estimation and calibration of a timepiece in a quantum dot system

Ping Dong, Zhuo-Liang Cao

Published Aug 22, 2007• 4 citations
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Abstract

We present a physical scheme for implementing quantum phase estimation via weakly coupled double-quantum-dot molecules embedded in a microcavity. During the same process of implementation, we can also realize the calibration of a timepiece based on the estimated phase. We use the electron–hole pair states in coupled double-quantum-dot molecules to encode quantum information, where the requirement that two quantum dots are exactly identical is not necessary. Our idea can also be generalized to other systems, such as atomic, trapped ion and linear optics systems.

DOI
10.1088/0953-8984/19/37/376216

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Using linear optical manipulation, single photons, entangled photon pairs, photon measurement, and classical communication, we propose a scheme for a two-spin-qubit phase gate and the teleportation of a controlled-not gate between two electron spins from acting on local qubits to acting on remote qubits using quantum dots in optical microcavities. The scheme is based on spin selective photon reflection from the cavity and is achieved in a deterministic way by the sequential detection of photons and the single-qubit rotations of a single electron spin in a self-assembled GaAs-InAs quantum dot. The feasibility of the scheme is assessed showing that high average fidelities of the gates are achievable in the weak-coupling regime when the side leakage and cavity loss are low. The scheme opens promising possibilities for long-distance quantum communication, distributed quantum computation, and construction of remote quantum-information-processing networks.
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