Resonance widths in open microwave cavities studied by harmonic inversion.

Area of Science:

• * Physics, specifically quantum chaos and microwave cavity resonance phenomena.
• * Application of advanced signal processing techniques to experimental data.

Background:

• * Understanding the behavior of resonances in open microwave cavities is crucial for studying complex systems.
• * Previous experimental methods were limited in resolving resonances when linewidths significantly exceed mean level spacing.

Purpose of the Study:

• * To determine the poles of the scattering matrix in the complex plane from reflection spectrum measurements.
• * To extract and analyze resonance properties, particularly linewidths, in a challenging experimental regime.
• * To compare experimental findings with theoretical predictions from random matrix theory.

Main Methods:

• * Measurement of the reflection spectrum of an open microwave cavity.
• * Application of the harmonic inversion method for resonance extraction.
• * Analysis of resonance linewidth distributions and comparison with theoretical models.

Main Results:

• * Successful determination of scattering matrix poles and extraction of resonances.
• * Resolution of resonances in a regime where linewidths are up to 10 times the mean level spacing, a novel experimental achievement.
• * Experimental linewidth distributions show excellent agreement with random matrix theory predictions, incorporating wall absorption and channel coupling effects.

Conclusions:

• * The harmonic inversion method provides unprecedented resolution for complex resonances in open microwave cavities.
• * The study validates the applicability of random matrix theory to describe resonance phenomena in this system, even under challenging conditions.
• * Findings open new avenues for experimental investigations into quantum chaotic systems.