Linear microwave response of a charge-type qubit

Author

Krech, Wolfram ; Born, Detlef ; Wagner, Thomas ; Meyer, Hans-Georg

Author_Institution

Inst. of Solid State Phys., Friedrich-Schiller-Univ., Jena, Germany

Volume

11

Issue

1

fYear

2001

fDate

3/1/2001 12:00:00 AM

Firstpage

1022

Lastpage

1025

Abstract

Using Bloch-type equations with phenomenological energy relaxation and dephasing terms, we investigate analytically the linear response of a superconducting charge qubit (single-Cooper-pair box) to a microwave field within a two-band model. Coherence of the macroscopic quantum states of the autonomous device is due to the competition of irradiation and dephasing. An extra qubit impedance arises from this quantum effect which can be expressed in terms of quantum resistance unit, quality and detuning. The theoretical results may support the design of microwave experiments with charge-type qubits. Especially, we present a proposal for determining the dephasing time by means of reflection measurements, anticipating a high quality of the extra (quantum) impedance

Keywords

Cooper pairs; superconducting integrated circuits; superconducting microwave devices; Bloch equation; autonomous device; dephasing time; detuning; energy relaxation; linear microwave response; macroscopic quantum coherence; microwave reflection; quantum impedance; quantum resistance; single Cooper pair box; superconducting charge qubit; two-band model; Equations; Impedance; Integrated circuit measurements; Josephson junctions; Magnetic flux; Physics; Solid state circuits; Superconducting device noise; Superconducting microwave devices; Time measurement;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.919523

Filename

919523