Diffractive orbits in the length spectrum of a 2D microwave cavity with a small scatterer

TL;DR

This study demonstrates how diffractive orbits influence the length spectrum of a 2D microwave cavity with a small scatterer, combining numerical, experimental, and semiclassical analysis.

Contribution

It provides the first experimental evidence of diffractive orbits affecting the spectrum of a microwave cavity with a small scatterer, advancing cavity defect detection methods.

Findings

Diffractive orbits significantly impact the length spectrum.

Experimental and numerical results agree on the role of diffractive orbits.

Potential for new cavity defect detection techniques.

Abstract

In a 2D rectangular microwave cavity dressed with one point-like scatterer, a semiclassical approach is used to analyze the spectrum in terms of periodic orbits and diffractive orbits. We show, both numerically and experimentally, how the latter can be accounted for in the so-called length spectrum which is retrieved from 2-point correlations of a finite range frequency spectrum. Beyond its fundamental interest, this first experimental evidence of the role played by diffractive orbits in the spectrum of an actual cavity, can be the first step towards a novel technique to detect and track small defects in wave cavities.