Single-Atom Amplification Assisted by Multiple Sideband Interference in 1D Waveguide QED Systems

TL;DR

This paper theoretically investigates signal amplification in 1D waveguide QED systems, revealing mechanisms involving multiple sideband interference and conditions for amplification without population inversion.

Contribution

It introduces a model accounting for multiple dressed sidebands in waveguide QED, explaining amplification mechanisms beyond population inversion.

Findings

Amplification occurs under specific resonant conditions.

Constructive interference of sidebands can cause amplification without population inversion.

Quibit dephasing affects the amplification process.

Abstract

This study conducts a theoretical investigation into the signal amplification arising from multiple Rabi sideband coherence within a one-dimensional waveguide quantum electrodynamics system. We utilize a semi-infinite waveguide to drive an anharmonic multi-level transmon with a strong coherent microwave field, examining the scattering behavior by introducing a probe signal. Our findings reveal signal amplification under specific resonant conditions, presenting spectra that reveal finer details than previously documented in the literature. To elucidate the mechanisms behind this amplification, we develop a model that explicitly accounts for multiple dressed sidebands in the presence of a strong driving field. From this model, we derive the reflection amplitude of the probe signal. Notably, our results indicate that amplification can occur due to either population inversion or, in some instances, through the constructive interference of multiple sidebands even in the absence of population inversion. Additionally, we explore how qubit dephasing impacts the amplification process.