Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor

article Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor published Federico Pegoraro author 88928 Philip Held author 68236 Jonas Lammers author Benjamin Brecht author 271500000-0003-4140-0556 Christine Silberhorn author 26263 288 department 623 department 15 department The two-qubit controlled-not (C-NOT) gate is an essential component for gate-based quantum circuits. In fact, its operation, combined with single qubit rotations allows to realise any quantum circuit. Several strategies have been adopted in order to build quantum gates. Among them, photonics offers the dual advantage of excellent isolation from the environment and ease of manipulation at the single qubit level. Here we adopt a scalable time-multiplexed approach in order to build a fully reconfigurable architecture capable of implementing a post-selected C-NOT gate with a fidelity of (93.8 ± 1.4)%. We then show how our time-multiplexed platform can be employed to combine a C-NOT and a single qubit gate in order to generate the four Bell states. Springer Science and Business Media LLC2026 eng Photonic Quantum ComputingTime-multiplexingQuantum Information Nature Communications 2041-172310.1038/s41467-026-74861-9 171 https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-026-74861-9/MediaObjects/41467_2026_74861_MOESM1_ESM.pdf https://doi.org/10.5281/zenodo.20396394 F. Pegoraro, P. Held, J. Lammers, B. Brecht, and C. Silberhorn, “Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor,” Nature Communications, vol. 17, no. 1, Art. no. 5683, 2026, doi: <a href="https://doi.org/10.1038/s41467-026-74861-9">10.1038/s41467-026-74861-9</a>. Pegoraro, F., Held, P., Lammers, J., Brecht, B., & Silberhorn, C. (2026). Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor. Nature Communications, 17(1), Article 5683. <a href="https://doi.org/10.1038/s41467-026-74861-9">https://doi.org/10.1038/s41467-026-74861-9</a> Pegoraro, Federico, Philip Held, Jonas Lammers, Benjamin Brecht, and Christine Silberhorn. “Demonstration of a Quantum C-NOT Gate in a Time-Multiplexed Fully Reconfigurable Photonic Processor.” Nature Communications 17, no. 1 (2026). <a href="https://doi.org/10.1038/s41467-026-74861-9">https://doi.org/10.1038/s41467-026-74861-9</a>. F. Pegoraro, P. Held, J. Lammers, B. Brecht, C. Silberhorn, Nature Communications 17 (2026). Pegoraro, Federico, et al. “Demonstration of a Quantum C-NOT Gate in a Time-Multiplexed Fully Reconfigurable Photonic Processor.” Nature Communications, vol. 17, no. 1, 5683, Springer Science and Business Media LLC, 2026, doi:<a href="https://doi.org/10.1038/s41467-026-74861-9">10.1038/s41467-026-74861-9</a>. @article{Pegoraro_Held_Lammers_Brecht_Silberhorn_2026, title={Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor}, volume={17}, DOI={<a href="https://doi.org/10.1038/s41467-026-74861-9">10.1038/s41467-026-74861-9</a>}, number={15683}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Pegoraro, Federico and Held, Philip and Lammers, Jonas and Brecht, Benjamin and Silberhorn, Christine}, year={2026} } Pegoraro F, Held P, Lammers J, Brecht B, Silberhorn C. Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor. Nature Communications. 2026;17(1). doi:<a href="https://doi.org/10.1038/s41467-026-74861-9">10.1038/s41467-026-74861-9</a> 660942026-07-01T07:47:15Z2026-07-01T08:15:21Z