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Quantum Bit Regeneration

Isaac L. Chuang·Yoshihisa Yamamoto
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Abstract

Decoherence and loss will limit the practicality of quantum cryptography and computing unless successful error correction techniques are developed. To this end, we have discovered a new scheme for perfectly detecting and rejecting the error caused by loss (amplitude damping to a reservoir at T=0), based on using a dual-rail representation of a quantum bit. This is possible because (1) balanced loss does not perform a ``which-path'' measurement in an interferometer, and (2) balanced quantum nondemolition measurement of the ``total'' photon number can be used to detect loss-induced quantum jumps without disturbing the quantum coherence essential to the quantum bit. Our results are immediately applicable to optical quantum computers using single photonics devices.

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Isaac L. Chuang, Yoshihisa Yamamoto. 1996-04-25. Quantum Bit Regeneration. https://doi.org/10.1103/physrevlett.76.4281

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