Tunable Superconducting Qubits with Flux-Independent Coherence

By M. Hutchings, J. Hertzberg, Yebing Liu, N. Bronn, G. Keefe, M. Brink, Jerry M. Chow, B. Plourde. 2017

163 citations recorded by the source corpus.

We have studied the impact of low-frequency magnetic flux noise upon superconducting transmon qubits with various levels of tunability. We find that qubits with weaker tunability exhibit dephasing that is less sensitive to flux noise. This insight was used to fabricate qubits where dephasing due to flux noise was suppressed below other dephasing sources, leading to flux-independent dephasing times T2* ~ 15 us over a tunable range of ~340 MHz. Such tunable qubits have the potential to create high-fidelity, fault-tolerant qubit gates and fundamentally improve scalability for a quantum processor.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/7acef9644048f9ac2e3e2764b02ee1eec11a1fa3

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In Artificial Intelligence

In Atomic and Molecular Physics, and Optics

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Citations in the corpus

Hardware-efficient variational quantum eigensolver for small molecules and quantum magnets (2017, methodology): “[1] National Energy Research Scientific Computing Center 2015 Annual Report.”
Realizing repeated quantum error correction in a distance-three surface code (2021, methodology): “We fabricated all qubits with asymmetric superconducting quantum interference devices (SQUIDs) [55, 56] to allow for data qubits to idle at their minimum and auxiliary qubits at their maximum frequencies, at which the qubits are to first-order insensitive to flux noise.”
Realization of High-Fidelity CZ and ZZ -Free iSWAP Gates with a Tunable Coupler (2020, background): “7 GHz) by modulating the external magnetic flux threading through their asymmetric SQUID loops [33].”
Parametrically Activated Entangling Gates Using Transmon Qubits (2017, background): “While fixedfrequency qubits generally have long coherence times, this architecture requires satisfying stringent constraints on qubit frequencies and anharmonicities [5, 6, 8] which requires some tunability to scale to many qubits [9].”
Tunable Coupling Scheme for Implementing High-Fidelity Two-Qubit Gates (2018, background): “Candidates for circuit implementation include single-junction or tunable transmons [28, 29], capacitively shunted flux qubits [30, 31], or capacitively shunted fluxonium qubits [32].”
Quantum Electrodynamics in a Topological Waveguide (2020, methodology): “[48] M.”