Photon-noise-tolerant dispersive readout of a superconducting qubit using a nonlinear Purcell filter

Fuente: arXiv
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Bibliographic Details
Main Authors: Sunada, Yoshiki, Yuki, Kenshi, Wang, Zhiling, Miyamura, Takeaki, Ilves, Jesper, Matsuura, Kohei, Spring, Peter A., Tamate, Shuhei, Kono, Shingo, Nakamura, Yasunobu
Format: Preprint
Published: 2023
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author Sunada, Yoshiki
Yuki, Kenshi
Wang, Zhiling
Miyamura, Takeaki
Ilves, Jesper
Matsuura, Kohei
Spring, Peter A.
Tamate, Shuhei
Kono, Shingo
Nakamura, Yasunobu
author_facet Sunada, Yoshiki
Yuki, Kenshi
Wang, Zhiling
Miyamura, Takeaki
Ilves, Jesper
Matsuura, Kohei
Spring, Peter A.
Tamate, Shuhei
Kono, Shingo
Nakamura, Yasunobu
contents Residual noise photons in a readout resonator become a major source of dephasing for a superconducting qubit when the resonator is optimized for a fast, high-fidelity dispersive readout. Here, we propose and demonstrate a nonlinear Purcell filter that suppresses such an undesirable dephasing process without sacrificing the readout performance. When a readout pulse is applied, the filter automatically reduces the effective linewidth of the readout resonator, increasing the sensitivity of the qubit to the input field. The noise tolerance of the device we have fabricated is shown to be enhanced by a factor of 3 relative to a device with a linear filter. The measurement rate is enhanced by another factor of 3 by utilizing the bifurcation of the nonlinear filter. A readout fidelity of 99.4% and a quantum nondemolition fidelity of 99.2% are achieved using a 40-ns readout pulse. The nonlinear Purcell filter will be an effective tool for realizing a fast, high-fidelity readout without compromising the coherence time of the qubit.
format Preprint
id arxiv_https___arxiv_org_abs_2309_04315
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Photon-noise-tolerant dispersive readout of a superconducting qubit using a nonlinear Purcell filter
Sunada, Yoshiki
Yuki, Kenshi
Wang, Zhiling
Miyamura, Takeaki
Ilves, Jesper
Matsuura, Kohei
Spring, Peter A.
Tamate, Shuhei
Kono, Shingo
Nakamura, Yasunobu
Quantum Physics
Residual noise photons in a readout resonator become a major source of dephasing for a superconducting qubit when the resonator is optimized for a fast, high-fidelity dispersive readout. Here, we propose and demonstrate a nonlinear Purcell filter that suppresses such an undesirable dephasing process without sacrificing the readout performance. When a readout pulse is applied, the filter automatically reduces the effective linewidth of the readout resonator, increasing the sensitivity of the qubit to the input field. The noise tolerance of the device we have fabricated is shown to be enhanced by a factor of 3 relative to a device with a linear filter. The measurement rate is enhanced by another factor of 3 by utilizing the bifurcation of the nonlinear filter. A readout fidelity of 99.4% and a quantum nondemolition fidelity of 99.2% are achieved using a 40-ns readout pulse. The nonlinear Purcell filter will be an effective tool for realizing a fast, high-fidelity readout without compromising the coherence time of the qubit.
title Photon-noise-tolerant dispersive readout of a superconducting qubit using a nonlinear Purcell filter
topic Quantum Physics
url https://arxiv.org/abs/2309.04315