Sharp electromagnetically induced absorption via balanced interferometric excitation in a microwave resonator

TL;DR

This paper demonstrates a method to achieve electromagnetically induced absorption in a microwave cavity by using a balanced interferometric setup to suppress electric fields while enhancing scalar potentials, enabling new tests of quantum effects.

Contribution

The work introduces a novel interferometric excitation technique in microwave resonators that suppresses electric fields and enhances scalar potentials, facilitating tests of the electric-scalar Aharonov-Bohm effect.

Findings

Achieved 25 dB suppression of electric field at resonance.

Enhanced cavity phase response by an order of magnitude.

Enabled potential testing of electric-scalar Aharonov-Bohm effect.

Abstract

A cylindrical TM$_{0,1,0}$ mode microwave cavity resonator was excited using a balanced interferometric configuration that allowed manipulation of the electric field and potential within the resonator by adjusting the phase and amplitude of the interferometer arms driving the resonator. With precise tuning of the phase and amplitude, 25 dB suppression of the electric field at the resonance frequency was achieved while simultaneously resonantly enhancing the time-varying electric-scalar potential. Under these conditions, the system demonstrated electromagnetically induced absorption in the cavity response due to the annulment of the electric field at the resonance frequency. This phenomena can be regarded as a form of extreme dispersion, and led to a sharp increase in the cavity phase versus frequency response by an order of magnitude when compared to the cavity Q-factor. This work presents an experimental setup that will allow the electric-scalar Aharonov-Bohm effect to be tested under conditions involving a time-varying electric-scalar potential, without the presence of an electric field or magnetic vector potential, an experiment that has not yet been realised.