Cooper-pair box as a variable capacitor

Author

Paik, Hanhee ; Strauch, F.W. ; Ramos, R.C. ; Berkley, A.J. ; Xu, H. ; Dutta, S.K. ; Johnson, P.R. ; Dragt, A.J. ; Anderson, J.R. ; Lobb, C.J. ; Wellstood, F.C.

Author_Institution

Coll. Park, Univ. of Maryland, College Park, MD, USA

Volume

15

Issue

2

fYear

2005

fDate

6/1/2005 12:00:00 AM

Firstpage

884

Lastpage

887

Abstract

We calculate the effective capacitance of a Cooper-pair box and demonstrate that the Cooper-pair box can be used as a variable capacitor. The gate voltage modulates the charge transfer through the small junction in the Cooper-pair box, leading to a gate-dependent capacitance. We describe ongoing experiments to use an Al/AlO_x/Al Cooper-pair box as a tunable circuit element at milli-Kelvin temperatures and discuss possible applications to quantum computing as a variable coupling element between two Josephson junction qubits.

Keywords

Cooper pairs; aluminium; aluminium compounds; capacitance measurement; circuit tuning; equivalent circuits; quantum computing; superconducting junction devices; varactors; Al-AlO-Al; Cooper-pair box; Josephson junction qubits; charge transfer; effective capacitance calculation; gate voltage; milliKelvin temperatures; quantum computing; tunable circuit element; variable capacitor; variable coupling element; Capacitors; Charge transfer; Computer applications; Coupling circuits; Josephson junctions; Quantum capacitance; Quantum computing; Temperature; Tunable circuits and devices; Voltage; Cooper-pair box; Josephson junction; qubit; variable capacitor;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2005.850100

Filename

1439780