Coherent Josephson phase qubit with a single crystal silicon capacitor

This paper used a suspended single-crystal silicon shunt capacitor to reduce dielectric loss in a Josephson phase qubit.

Key Results

Measured energy-relaxation times up to $T_{1} = 1.6 μ s$
Measured $T_{2}^{*} = 110$ ns at a 5.093 GHz operating point
Demonstrated more than a factor-of-two $T_{1}$ improvement over amorphous-shunt phase qubits