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arXiv · 1208.0818

Ultimate charge sensitivity and efficiency of a quantum point contact with a superposed input state

Kang-Ho Lee·Kicheon Kang
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Abstract

We address the ultimate charge detection scheme with a quantum point contact. It is shown that a superposed input state is necessary to exploit the full sensitivity of a quantum point contact detector. The coherence of the input state provides an improvement in charge sensitivity, and this improvement is a result of the fundamental property of the scattering matrix. Further, a quantum-limited (maximally efficient) detection is possible by controlling the interference between the two output waves. Our scheme provides the ultimate sensitivity and efficiency of charge detection with a generic quantum point contact.

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Kang-Ho Lee, Kicheon Kang. 2012-08-03. Ultimate charge sensitivity and efficiency of a quantum point contact with a superposed input state. https://doi.org/10.1103/physrevb.87.045407

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