B.L.T. Plourde

Superconducting qubit in a waveguide cavity with a coherence time approaching 0.1 ms

We report a superconducting artificial atom with a coherence time of

Solid-state qubits with current-controlled coupling

{T}_{2}^{*}=92

First-order sideband transitions with flux-driven asymmetric transmon qubits

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Microwave Response of Vortices in Superconducting Thin Films of Re and Al

s and energy relaxation time

Entangling flux qubits with a bipolar dynamic inductance

{T}_{1}=70

Flux Qubits and Readout Device with Two Independent Flux Lines

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Long-Range Coupling and Scalable Architecture for Superconducting Flux Qubits

s. The system consists of a single Josephson junction transmon qubit on a sapphire substrate embedded in an otherwise empty copper waveguide cavity whose lowest eigenmode is dispersively coupled to the qubit transition. We attribute the factor of four increase in the coherence quality factor relative to previous reports to device modifications aimed at reducing qubit dephasing from residual cavity photons. This simple device holds promise as a robust and easily produced artificial quantum system whose intrinsic coherence properties are sufficient to allow tests of quantum error correction.

Process verification of two-qubit quantum gates by randomized benchmarking

The ability to switch the coupling between quantum bits (qubits) on and off is essential for implementing many quantum-computing algorithms. We demonstrated such control with two flux qubits coupled together through their mutual inductances and through the dc superconducting quantum interference device (SQUID) that reads out their magnetic flux states. A bias current applied to the SQUID in the zero-voltage state induced a change in the dynamic inductance, reducing the coupling energy controllably to zero and reversing its sign.