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QI: Fachverband Quanteninformation

QI 4: Quantum Computing and Simulation (joint session Q/QI)

QI 4.3: Vortrag

Montag, 6. März 2023, 11:30–11:45, E214

Realization of a photonic ultra-fast free space discrete-time quantum walk. — •Jonas Lammers, Syamsundar De, Nidhin Prasannan, Benjamin Brecht, and Christine Silberhorn — Paderborn University, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), Warburger Straße 100, 33098 Paderborn, Germany

Recent developments in quantum systems based on time-multiplexed techniques have shown high potential for quantum communication and information processing protocols. The time-multiplexed architecture has already been used in experiments demonstrating exponential increase in GHZ state generation and quantum advantage based on Gaussian boson sampling. Here we demonstrate an ultra-fast free space discrete-time quantum walk. With the newest generation of SNSPDs enabling higher than ever timing resolutions, we were able to overcome the need for long optical delay paths - typically optical fibers - in time-multiplexed systems. The resulting free space architecture enables us to increase measurement repetition rates by multiple orders of magnitude and promises increased stability. Furthermore, we can expect an increase in efficiency which would lead to an exponential increase in observable step numbers. We performed a full polarization resolved quantum walk characterization using coherent light and heralded single photons, observing up to twenty quantum walk steps with high similarity to theory. The demonstrated ultra-fast quantum walk is a promising platform for quantum simulations and opens up a path for large-scale quantum photonic networks utilizing time-multiplexing.