Superconducting terminals as sensitive probes for scarred states.

Kormanyos, Andor and Schomerus, Henning (2006) Superconducting terminals as sensitive probes for scarred states. Physical review letters, 97 (12). p. 124102. ISSN 1079-7114

Abstract

When a quantum-chaotic normal conductor is coupled to a superconductor, the random-matrix theory (RMT) predicts that a gap opens up in the excitation spectrum which is of universal size E_g^RMT approx 0.3 hbar/tD, where tD is the mean scattering time between Andreev reflections. We show that a scarred state of long lifetime tS>>tD suppresses the excitation gap over a window Delta E approx 2E_g^RMT which can be much larger than the narrow resonance width Gamma_S=hbar/tS of the scar in the normal system. The minimal value of the excitation gap within this window is given by Gamma_S/2<<E_g^RMT. Via this suppression of the gap to a nonuniversal value, the scarred state can be detected over a much larger energy range than it is in the case when the superconducting terminal is replaced by a normal one.