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Biomedical subjects

G Vattay

Publications and source records attributed to G Vattay.

15 recordsLinked to original sources
PubMed2001

Trace formula for noise corrections to trace formulas.

We consider an evolution operator for a discrete Langevin equation with a strongly hyperbolic classical dynamics and Gaussian noise. Using an integral representation of the evolution operator L, we investigate the high-order corrections to the trace of L(n). The asymptotic behavior is found to be controlled by subdominant saddle points previously neglected in the perturbative expansion. We show that a trace formula can be derived to describe the high-order noise corrections.

Journal Article↗
PubMed2000

Negative length orbits in normal-superconductor billiard systems

The path-length spectra of mesoscopic systems including diffractive scatterers and connected to a superconductor are studied theoretically. We show that the spectra differ fundamentally from that of normal systems due to the presence of Andreev reflection. It is shown that negative path lengths should arise in the spectra as opposed to the normal system. To highlight this effect we carried out both quantum mechanical and semiclassical calculations for the simplest possible diffractive scatterer. The most pronounced peaks in the path-length spectra of the reflection amplitude are identified by the routes that the electron and/or hole travels.

Journal Article↗