Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 58: Transport: Poster Session
TT 58.14: Poster
Mittwoch, 9. März 2016, 15:00–18:30, Poster D
Coupling a gate tunable qubit to a 3D cavity — •Steffen Schlör1, Patrick Zellekens2, Thomas Schäpers2, Alexey V. Ustinov1, and Martin Weides1,3 — 1Physikalisches Institut, Karlsruhe Institut of Technology — 2Peter Grünberg Institut (PGI9), Forschungszentrum Jülich — 3Institute of Physics, Johannes Gutenberg University Mainz
The goal of the presented work is to implement a voltage tunable superconducting qubit. This kind of circuit could simplify architectures for quantum processors and enable the use of tunable qubits in magnetically sensitive environments. Electrostatic tunability of the Josephson coupling energy can be realized by using a superconductor/semiconductor nanowire as a weak link [1]. The field-dependent charge carrier density in the semiconductor provides a tunable nonlinear inductance.
The presented design includes a 3D microwave cavity promising good isolation of the qubit from the environment. Spectroscopy and time-resolved microwave measurements are performed in a wet 3He/4He cryostat at a temperature of 20 mK. We show simulations of the coupling to the cavity via the electric dipole moment as well as the electromagnetic field distribution. This coupling is important with respect to the electrostatic gate electrode, which has to be implemented without affecting the qubit coherence. Preliminary measurements of the mode spectrum show high internal coherence of the cavity.
Larsen et al., PRL 115, 127001 (2015)