aqora

Improving Quantum Hardware: Building New Superconducting Qubits and Couplers

Thomas Hazard

Jan 1, 20190 citations

High speed calibration and characterization of superconducting qubits without qubit reset

Max Werninghaus, Daniel J. Egger, Stefan Filipp

Bulletin of the American Physical SocietyMar 17, 20210 citations

Learning-Based Calibration of Flux Crosstalk in Transmon Qubit Arrays

Cora N. Barrett, Amir H. Karamlou, Sarah E. Muschinske +13 more

Superconducting quantum processors comprising flux-tunable data and coupler qubits are a promising platform for quantum computation. However, magnetic flux crosstalk between the flux-control lines and the constituent qubits impedes precision control of qubit frequencies, presenting a challenge to scaling this platform. In order to implement high-fidelity digital and analog quantum operations, one must characterize the flux crosstalk and compensate for it. In this work, we introduce a learning-based calibration protocol and demonstrate its experimental performance by calibrating an array of 16 flux-tunable transmon qubits. To demonstrate the extensibility of our protocol, we simulate the crosstalk matrix learning procedure for larger arrays of transmon qubits. We observe an empirically linear scaling in calibration time with system size while maintaining a median qubit frequency error below 300 kHz.Superconducting quantum processors comprising flux-tunable data and coupler qubits are a promising platform for quantum computation. However, magnetic flux crosstalk between the flux-control lines and the constituent qubits impedes precision control of qubit frequencies, presenting a challenge to scaling this platform. In order to implement high-fidelity digital and analog quantum operations, one must characterize the flux crosstalk and compensate for it. In this work, we introduce a learning-based calibration protocol and demonstrate its experimental performance by calibrating an array of 16 flux-tunable transmon qubits. To demonstrate the extensibility of our protocol, we simulate the crosstalk matrix learning procedure for larger arrays of transmon qubits. We observe an empirically linear scaling in calibration time with system size while maintaining a median qubit frequency error below 300 kHz.

arXiv:2303.03347Physical Review AppliedAug 28, 202321 citations

Model Free Gate Design and Calibration For Superconducting Qubits

Daniel J. Egger, Frank K. Wilhelm

Bulletin of the American Physical SocietyMar 3, 20140 citations

Characterization of tunable coupler without a dedicated readout resonator in superconducting circuits

Chi Zhang, Tian-Le Wang, Liang-Liang Guo +6 more

Tunable couplers have recently emerged as an essential component in superconducting quantum processors. These couplers usually do not have readout resonators to save control or hardware overhead; this makes it challenging to characterize and calibrate the coupler, which will undoubtedly limit the performance of a fast two-qubit gate. Here, we theoretically demonstrate that by mapping the coupler's state onto that of its neighboring qubit, the high-contrast readout of the coupler can be realized. We experimentally implement such a readout scheme with a single-shot readout fidelity of 86%, which is mainly limited by the thermal population of our sample. We further demonstrate how to calibrate the flux crosstalk related to the coupler and its flux distortion that are ignored in the previous works. These calibration steps are imperative for realizing robust and accurate quantum operations in frequency-tunable superconducting circuits.Tunable couplers have recently emerged as an essential component in superconducting quantum processors. These couplers usually do not have readout resonators to save control or hardware overhead; this makes it challenging to characterize and calibrate the coupler, which will undoubtedly limit the performance of a fast two-qubit gate. Here, we theoretically demonstrate that by mapping the coupler's state onto that of its neighboring qubit, the high-contrast readout of the coupler can be realized. We experimentally implement such a readout scheme with a single-shot readout fidelity of 86%, which is mainly limited by the thermal population of our sample. We further demonstrate how to calibrate the flux crosstalk related to the coupler and its flux distortion that are ignored in the previous works. These calibration steps are imperative for realizing robust and accurate quantum operations in frequency-tunable superconducting circuits.

Applied Physics LettersJan 9, 202311 citations

Engineering and control of coupled superconducting qubits arrays for quantum simulation

Edward Henry, Andrew Schmidt, Oliver Viehmann +1 more

Bulletin of the American Physical SocietyMar 18, 20130 citations

Automatic calibration of arrays of superconducting qubits and couplers

Related papers

Automatic calibration of arrays of superconducting qubits and couplers

Related papers