Microwave fidelity studies by varying antenna coupling

TL;DR

This study investigates how varying antenna coupling affects fidelity decay in microwave billiards, experimentally validating a theoretical model with different antenna terminators and demonstrating quantitative agreement.

Contribution

It introduces an experimental analysis of coupling fidelity in microwave billiards with different antenna terminations, confirming the theoretical model with complex coupling constants.

Findings

Quantitative agreement between experiment and theory.

Different antenna terminators influence fidelity decay.

Validation of the modified VWZ approach.

Abstract

The fidelity decay in a microwave billiard is considered, where the coupling to an attached antenna is varied. The resulting quantity, coupling fidelity, is experimentally studied for three different terminators of the varied antenna: a hard wall reflection, an open wall reflection, and a 50 Ohm load, corresponding to a totally open channel. The model description in terms of an effective Hamiltonian with a complex coupling constant is given. Quantitative agreement is found with the theory obtained from a modified VWZ approach [Verbaarschot et al, Phys. Rep. 129, 367 (1985)].