Models of environment and T_1 relaxation in Josephson Charge Qubits
Abstract
A theoretical interpretation of the recent experiments of Astafiev et. al. on the T_1-relaxation rate in Josephson Charge Qubits is proposed. The experimentally observed reproducible nonmonotonic dependence of T_1 on the splitting E_J of the qubit levels suggests further specification of the previously proposed models of the background charge noise. From our point of view the most promising is the ``Andreev fluctuator'' model of the noise. In this model the fluctuator is a Cooper pair that tunnels from a superconductor and occupies a pair of localized electronic states. Within this model one can naturally explain both the average linear T_1(E_J) dependence and the irregular fluctuations. The role of fluctuators in the formation of strong resonant peaks in this dependence is also discussed.
Cite
@article{arxiv.cond-mat/0411425,
title = {Models of environment and T_1 relaxation in Josephson Charge Qubits},
author = {Lara Faoro and Joakim Bergli and Boris L. Altshuler and Yuri M. Galperin},
journal= {arXiv preprint arXiv:cond-mat/0411425},
year = {2009}
}
Comments
4 pages, 3 figures