Decoherence benchmarking of superconducting qubits
Journal article, 2019

We benchmark the decoherence of superconducting transmon qubits to examine the temporal stability of energy relaxation, dephasing, and qubit transition frequency. By collecting statistics during measurements spanning multiple days, we find the mean parameters (T) over bar (1) = 49 mu s and (T) over bar (2)* = 95 mu s; however, both of these quantities fluctuate, explaining the need for frequent re-calibration in qubit setups. Our main finding is that fluctuations in qubit relaxation are local to the qubit and are caused by instabilities of near-resonant two-level-systems (TLS). Through statistical analysis, we determine sub-millihertz switching rates of these TLS and observe the coherent coupling between an individual TLS and a transmon qubit. Finally, we find evidence that the qubit's frequency stability produces a 0.8 ms limit on the pure dephasing which we also observe. These findings raise the need for performing qubit metrology to examine the reproducibility of qubit parameters, where these fluctuations could affect qubit gate fidelity.

resonators

transmon cubbits

circuits

Author

Jonathan Burnett

National Physical Laboratory (NPL)

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Andreas Bengtsson

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Marco Scigliuzzo

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

David Niepce

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Marina Kudra

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Per Delsing

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Jonas Bylander

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

NPJ QUANTUM INFORMATION

2056-6387 (ISSN)

Vol. 5 1 54

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1038/s41534-019-0168-5

More information

Latest update

6/22/2020