Broadband generation and tomography of non-Gaussian states for ultra-fast optical quantum processors

Akito Kawasaki; Ryuhoh Ide; Hector Brunel; Takumi Suzuki; Rajveer Nehra; Katsuki Nakashima; Takahiro Kashiwazaki; Asuka Inoue; Takeshi Umeki; Fumihiro China; Masahiro Yabuno; Shigehito Miki; Hirotaka Terai; Taichi Yamashima; Atsushi Sakaguchi; Kan Takase; Mamoru Endo; Warit Asavanant; Akira Furusawa

doi:10.1038/s41467-024-53408-w

Broadband generation and tomography of non-Gaussian states for ultra-fast optical quantum processors

Nat Commun. 2024 Nov 1;15(1):9075. doi: 10.1038/s41467-024-53408-w.

Authors

Akito Kawasaki¹, Ryuhoh Ide², Hector Brunel^{2

3}, Takumi Suzuki², Rajveer Nehra^{2

4

5}, Katsuki Nakashima², Takahiro Kashiwazaki⁶, Asuka Inoue⁶, Takeshi Umeki⁶, Fumihiro China⁷, Masahiro Yabuno⁷, Shigehito Miki⁷, Hirotaka Terai⁷, Taichi Yamashima², Atsushi Sakaguchi⁸, Kan Takase^{2

8}, Mamoru Endo^{2

8}, Warit Asavanant^{9

10}, Akira Furusawa^{11

12}

Affiliations

¹ Department of Applied Physics, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. [email protected].
² Department of Applied Physics, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
³ Department of Physics, Ecole Normale Supérieure, Paris, France.
⁴ Department of Electrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA, USA.
⁵ Department of Physics, University of Massachusetts Amherst, Amherst, MA, USA.
⁶ NTT Device Technology Labs, NTT Corporation, Atsugi, Kanagawa, Japan.
⁷ Advanced ICT Research Institute, National Institute of Information and Communications Technology, Nishi, Kobe, Japan.
⁸ Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, Wako, Saitama, Japan.
⁹ Department of Applied Physics, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. [email protected].
¹⁰ Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, Wako, Saitama, Japan. [email protected].
¹¹ Department of Applied Physics, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan. [email protected].
¹² Optical Quantum Computing Research Team, RIKEN Center for Quantum Computing, Wako, Saitama, Japan. [email protected].

Abstract

Quantum information processors benefit from high clock frequencies to fully harness quantum advantages before they are lost to decoherence. All-optical systems offer unique benefits due to their inherent 100-THz carrier frequency, enabling the development of THz-clock frequency processors. However, the bandwidth of quantum light sources and measurement devices has been limited to the MHz range, with nonclassical state generation rates in the kHz range. In this study, we demonstrated broadband generation and quantum tomography of non-Gaussian states using an optical parametric amplifier (OPA) as a squeezed light source and an optical phase-sensitive amplifier (PSA). Our system includes a 6-THz squeezed-light source, a 6-THz PSA, and a 66-GHz homodyne detector. We successfully generated non-Gaussian states at a 0.9 MHz rate with sub-nanosecond wave packets using a continuous-wave laser. The performance is currently limited by the jitter of superconducting detectors, restricting the usable bandwidth to 1 GHz. Our technique extends the bandwidth to GHz, potentially increasing non-Gaussian state generation rates for practical optical quantum processors using OPAs.

Abstract

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