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Coherent state LOQC gates using simplified diagonal superposition resource states

A. P. Lund·T. C. Ralph
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Abstract

In this paper we explore the possibility of fundamental tests for coherent state optical quantum computing gates [T. C. Ralph, et. al, Phys. Rev. A \textbf{68}, 042319 (2003)] using sophisticated but not unrealistic quantum states. The major resource required in these gates are state diagonal to the basis states. We use the recent observation that a squeezed single photon state ($\hat{S}(r) \ket{1}$) approximates well an odd superposition of coherent states ($\ketα - \ket{-α}$) to address the diagonal resource problem. The approximation only holds for relatively small $α$ and hence these gates cannot be used in a scaleable scheme. We explore the effects on fidelities and probabilities in teleportation and a rotated Hadamard gate.

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A. P. Lund, T. C. Ralph. 2004-10-26. Coherent state LOQC gates using simplified diagonal superposition resource states. https://doi.org/10.1103/physreva.71.032305

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