Andreev billiards

dc.creatorBeenakker, C. W. J.
dc.date2004-06-01
dc.date2004-07-09
dc.date.accessioned2026-07-25T15:36:07Z
dc.descriptionThis is a review of recent advances in our understanding of how Andreev reflection at a superconductor modifies the excitation spectrum of a quantum dot. The emphasis is on two-dimensional impurity-free structures in which the classical dynamics is chaotic. Such Andreev billiards differ in a fundamental way from their non-superconducting counterparts. Most notably, the difference between chaotic and integrable classical dynamics shows up already in the level density, instead of only in the level--level correlations. A chaotic billiard has a gap in the spectrum around the Fermi energy, while integrable billiards have a linearly vanishing density of states. The excitation gap E_gap corresponds to a time scale h/E_gap which is classical (h-independent, equal to the mean time t_dwell between Andreev reflections) if t_dwell is sufficiently large. There is a competing quantum time scale, the Ehrenfest time t_E, which depends logarithmically on h. Two phenomenological theories provide a consistent description of the t_E-dependence of the gap, given qualitatively by E_gap min(h/t_dwell,h/t_E). The analytical predictions have been tested by computer simulations but not yet experimentally.
dc.description22 pages including 24 figures; [v2] new sections III, VI.C; [v3] major revision of section VIII.B, correcting the effective RMT of cond-mat/0208192
dc.identifierhttps://arxiv.org/abs/cond-mat/0406018
dc.identifierhttp://arxiv.org/abs/cond-mat/0406018
dc.identifierLect. Notes Phys. 667, 131 (2005)
dc.identifierdoi:10.1007/11358817_4
dc.identifier.urihttps://dspace.dare.co.zw/handle/123456789/35282
dc.subjectMesoscale and Nanoscale Physics
dc.titleAndreev billiards
dc.typetext

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