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arXiv · 2404.07317

Building a controlled-NOT gate between polarization and frequency

Hsuan-Hao Lu·Joseph M. Lukens·Muneer Alshowkan·Brian T. Kirby·Nicholas A. Peters
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Abstract

By harnessing multiple degrees of freedom (DoFs) within a single photon, controlled quantum unitaries, such as the two-qubit controlled-NOT (CNOT) gate, play a pivotal role in advancing quantum communication protocols like dense coding and entanglement distillation. In this work, we devise and realize a CNOT operation between polarization and frequency DoFs by exploiting directionally dependent electro-optic phase modulation within a fiber Sagnac loop. Alongside computational basis measurements, we validate the effectiveness of this operation through the synthesis of all four Bell states in a single photon, all with fidelities greater than 98%. This demonstration opens new avenues for manipulating hyperentanglement across these two crucial DoFs, marking a foundational step toward leveraging polarization-frequency resources in fiber networks for future quantum applications.

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Hsuan-Hao Lu, Joseph M. Lukens, Muneer Alshowkan, Brian T. Kirby, Nicholas A. Peters. 2024-04-10. Building a controlled-NOT gate between polarization and frequency. https://doi.org/10.1364/opticaq.525837

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