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Title: Effect of quantum fluctuations on even-odd energy difference in a Cooper-pair box

Abstract

We study the effect of quantum charge fluctuations on the discrete spectrum of charge states of a small superconducting island (Cooper-pair box) connected to a large finite-size superconductor by a tunnel junction. In particular, we calculate the reduction of the even-odd energy difference {delta}E due to virtual tunneling of electrons across the junction. We show that the renormalization effects are important for understanding the quasiparticle ''poisoning'' effect because {delta}E determines the activation energy of a trapped quasiparticle in the Cooper-pair box. We find that renormalization of the activation energy depends on the dimensionless normal-state conductance of the junction g{sub T} and becomes strong at g{sub T}>>1.

Authors:
 [1]
  1. W.I. Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States)
Publication Date:
OSTI Identifier:
20951513
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 21; Other Information: DOI: 10.1103/PhysRevB.75.212501; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; ACTIVATION ENERGY; CHARGE STATES; COOPER PAIRS; ELECTRONS; FLUCTUATIONS; QUASI PARTICLES; RENORMALIZATION; SPECTRA; SUPERCONDUCTING JUNCTIONS; SUPERCONDUCTORS; TRAPPING; TUNNEL EFFECT

Citation Formats

Lutchyn, R. M. Effect of quantum fluctuations on even-odd energy difference in a Cooper-pair box. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.212501.
Lutchyn, R. M. Effect of quantum fluctuations on even-odd energy difference in a Cooper-pair box. United States. doi:10.1103/PHYSREVB.75.212501.
Lutchyn, R. M. Fri . "Effect of quantum fluctuations on even-odd energy difference in a Cooper-pair box". United States. doi:10.1103/PHYSREVB.75.212501.
@article{osti_20951513,
title = {Effect of quantum fluctuations on even-odd energy difference in a Cooper-pair box},
author = {Lutchyn, R. M.},
abstractNote = {We study the effect of quantum charge fluctuations on the discrete spectrum of charge states of a small superconducting island (Cooper-pair box) connected to a large finite-size superconductor by a tunnel junction. In particular, we calculate the reduction of the even-odd energy difference {delta}E due to virtual tunneling of electrons across the junction. We show that the renormalization effects are important for understanding the quasiparticle ''poisoning'' effect because {delta}E determines the activation energy of a trapped quasiparticle in the Cooper-pair box. We find that renormalization of the activation energy depends on the dimensionless normal-state conductance of the junction g{sub T} and becomes strong at g{sub T}>>1.},
doi = {10.1103/PHYSREVB.75.212501},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 21,
volume = 75,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}