Quasiparticle transport in arrays of chaotic cavities

Abstract

– We find the distribution of transmission eigenvalues in a series of identical junctions between chaotic cavities using the circuit theory of mesoscopic transport. This distribution rapidly approaches the diffusive wire limit as the number of junctions increases, independent of the specific scattering properties of a single junction. The cumulant generating function and the first three cumulants of the charge transfer through the system are obtained both in the normal and in the superconducting state. Introduction. – Higher-order correlators of current fluctuations in mesoscopic conductors have been studied extensively over the last decade both theoretically [1–7] and experimentally [8–18]. The reason is that they contain, in general, additional information to the usual differential conductance such as higher moments of the transmission eigenvalue distribution, the value of effective charge involved in transport processes, the size of internal energy scales of the system or the correlations intrinsic to the many-body state of entangled systems [19–21]. While the conductance is proportional to the average transmission probability of the structure at low temperatures, the current noise power PI depends on the second moment of transmission eigenvalue distribution which is characterized by the Fano factor F = PI/2eI = [ ∑ n Tn(1−Tn)]/ ∑ n Tn. Here e is the electron charge, I is the average current through the sample, and Tn are the transmission eigenvalues. Recent experiments on noise confirmed the theoretical predictions [2,3] on the universal distributions of transmission eigenvalues in a metallic diffusive wire [8, 9] and in an open chaotic cavity [10] with Fano factors F = 1/3 and F = 1/4, respectively. The crossover from a single cavity to the diffusive wire limit as the number of internal junctions increases was studied experimentally by Oberholzer et al. [10] and Song et al. [11] recently. Particle-hole correlations introduced by a superconducting terminal also modify the noise. The low temperature noise of the subgap transport is doubled for tunnel junctions [12] and in diffusive normal wires in contact with a superconductor [13, 14]. The noise in an open cavity is found to be more than two times larger in the superconducting state [15] than in the corresponding normal state junction, in agreement with theoretical predictions [2].

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Cite this paper

@inproceedings{Vanevi2006QuasiparticleTI, title={Quasiparticle transport in arrays of chaotic cavities}, author={Mihajlo Vanevi{\'c} and Wolfgang Belzig}, year={2006} }