Active protection of a superconducting qubit with an interferometric Josephson isolator

被引：34

作者：

Abdo, Baleegh ^{[1
]}

Bronn, Nicholas T. ^{[1
]}

Jinka, Oblesh ^{[1
]}

Olivadese, Salvatore ^{[1
]}

Corcoles, Antonio D. ^{[1
]}

Adiga, Vivekananda P. ^{[1
]}

Brinks, Markus ^{[1
]}

Lake, Russell E. ^{[2
,3
]}

Wu, Xian ^{[2
]}

Pappas, David P. ^{[2
]}

Chow, Jerry M. ^{[1
]}

机构：

[1] IBM TJ Watson Res Ctr, New York, NY 10598 USA

[2] NIST, Boulder, CO 80305 USA

[3] Bluefors Oy, Arinatie 10, Helsinki 00370, Finland

来源：

NATURE COMMUNICATIONS | 2019年 / 10卷

关键词：

QUANTUM; PHOTON; NOISE;

D O I：

10.1038/s41467-019-11101-3

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Nonreciprocal microwave devices play critical roles in high-fidelity, quantum-nondemolition (QND) measurement schemes. They impose unidirectional routing of readout signals and protect the quantum systems from unwanted noise originated by the output chain. However, cryogenic circulators and isolators are disadvantageous in scalable superconducting architectures because they use magnetic materials and strong magnetic fields. Here, we realize an active isolator formed by coupling two nondegenerate Josephson mixers in an interferometric scheme and driving them with phase-shifted, same-frequency pumps. By incorporating our Josephson-based isolator into a superconducting qubit setup, we demonstrate fast, high-fidelity, QND measurements of the qubit while providing 20 dB of protection within a bandwidth of 10 MHz against amplified noise reflected off the Josephson amplifier in the output chain. A moderate reduction of 35% is observed in T-2E when the Josephson-based isolator is turned on. Such a moderate degradation can be mitigated by minimizing heat dissipation in the pump lines.

引用

页数：10

共 61 条

[1] Multi-path interferometric Josephson directional amplifier for qubit readout [J].