Measurements of the decoherence time from energy level quantization in Josephson junctions and rf SQUIDs

Author

Cosmelli, C. ; Chiarello, F. ; D´Agosta, G. ; Castellano, M.G. ; Torrioli, G.

Author_Institution

Dipt. di Fisica, Ist. Nazionale di Fisica Nucl., Rome, Italy

Volume

9

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

4123

Lastpage

4126

Abstract

We have measured the effective resistance of a Josephson junction and of an rf SQUID cooled at a temperature between 18 mK and 35 mK. From a fit of the data with a simplified solution of the master equation describing the system dynamics we found for both devices an effective resistance R/spl ap/4-5 M/spl Omega/. This value, in the same system cooled at 5 mK, would lead to a decoherence time of approximately 1.1 /spl mu/s allowing one to perform measurements of the Rabi oscillations having a tunneling frequency of the order of few MHz. This value is very promising also for the realization of qu-bits realized by means of Josephson devices.

Keywords

Josephson effect; SQUIDs; quantum computing; 18 to 35 mK; 4 to 5 Mohm; Josephson junctions; Rabi oscillations; decoherence time; effective resistance; energy level quantization; master equation; qu-bits; rf SQUIDs; system dynamics; tunneling frequency; Electrical resistance measurement; Energy measurement; Energy states; Equations; Josephson junctions; Performance evaluation; Quantization; SQUIDs; Temperature; Time measurement;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.783933

Filename

783933