The semiclassical relation between open trajectories and periodic orbits for the Wigner time delay

TL;DR

This paper establishes a semiclassical connection between open scattering trajectories and trapped periodic orbits in chaotic quantum systems, revealing their equivalence in describing the Wigner time delay.

Contribution

It derives the periodic orbit formula from scattering trajectories and introduces a new correlation mechanism involving trajectories near trapped orbits.

Findings

Derived all terms in the periodic orbit formula from scattering trajectories.

Identified a new correlation due to trajectories approaching trapped orbits.

Showed no leading-order periodic orbit contributions in conductance calculations.

Abstract

The Wigner time delay of a classically chaotic quantum system can be expressed semiclassically either in terms of pairs of scattering trajectories that enter and leave the system or in terms of the periodic orbits trapped inside the system. We show how these two pictures are related on the semiclassical level. We start from the semiclassical formula with the scattering trajectories and derive from it all terms in the periodic orbit formula for the time delay. The main ingredient in this calculation is a new type of correlation between scattering trajectories which is due to trajectories that approach the trapped periodic orbits closely. The equivalence between the two pictures is also demonstrated by considering correlation functions of the time delay. A corresponding calculation for the conductance gives no periodic orbit contributions in leading order.