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DOE OSTI · 1661226

Fully Arbitrary Control of Frequency-Bin Qubits

Lu, Hsuan-Hao·Simmerman, Emma M.·Lougovski, Pavel·Weiner, Andrew M.·Lukens, Joseph M.
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Abstract

Accurate control of two-level systems is a longstanding problem in quantum mechanics. One such quantum system is the frequency-bin qubit: a single photon existing in superposition of two discrete frequency modes. In this Letter, we demonstrate fully arbitrary control of frequency-bin qubits in a quantum frequency processor for the first time. Furthermore, we numerically establish optimal settings for multiple configurations of electro-optic phase modulators and pulse shapers, experimentally confirming near-unity mode-transformation fidelity for all fundamental rotations. Performance at the single-photon level is validated through the rotation of a single frequency-bin qubit to 41 points spread over the entire Bloch sphere, as well as tracking of the state path followed by the output of a tunable frequency beam splitter, with Bayesian tomography confirming state fidelities Fρ>0.98 for all cases. Overall, such high-fidelity transformations expand the practical potential of frequency encoding in quantum communications, offering exceptional precision and low noise in general qubit manipulation.

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71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICSOptical quantum information processingoptoelectronicsphotonicsquantum gatesquantum opticsquantum tomography

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Lu, Hsuan-Hao, Simmerman, Emma M., Lougovski, Pavel, Weiner, Andrew M., Lukens, Joseph M.. 2020-09-14. Fully Arbitrary Control of Frequency-Bin Qubits. https://doi.org/10.1103/physrevlett.125.120503

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