Fluctuation amplification engineering in multimode Raman-cavity systems

TL;DR

This paper explores how multi-mode Raman-cavity systems can be engineered to control and amplify fluctuations non-reciprocally, with potential applications in quantum sensing and spectroscopy.

Contribution

It generalizes fluctuation engineering to multi-mode systems, demonstrating collective fluctuation control and superlinear amplification scaling.

Findings

Resonant and non-resonant collective fluctuations emerge in multi-mode systems.

Fluctuations can be selectively attenuated or amplified by engineering band dispersion.

Cavity fluctuation amplification surpasses the  scaling with more modes.

Abstract

Parametric amplification is a key ingredient of a wide range of phenomena, from the classical to the quantum domain. Although such phenomena have been demonstrated in non-equilibrium settings, their use for fluctuation engineering has been put forth in Raman-cavity hybrids only recently. In this work, we generalize fluctuation engineering to a multi-mode scenario in which multiple Raman-active modes interact nonlinearly with multiple cavity modes. We demonstrate the emergence of resonant and non-resonant collective fluctuations that can be non-reciprocally controlled by engineering the band dispersion of photons and phonons. As an example we show how Raman fluctuations can be selectively attenuated by tuning the photonic bandgap or even nonresonantly amplified, in marked contrast to the single-mode scenario. We also identify a regime in which the amplification of cavity fluctuations in a specific mode is boosted, surpassing a $\sqrt{N}$ scaling with increasing number of $N$ Raman and cavity modes. Our study reveals the key role of multi-mode interactions on fluctuations in nonlinear cavity-matter hybrids. Noise engineering through different photon and phonon dispersions, as demonstrated here, could be leveraged for the design of novel quantum sensing platforms and advanced spectroscopy in the THz regime.