Quantum control and signal enhancement exploiting the Stokes-anti-Stokes coherence

Abstract

We present a theoretical framework for the coherent coupling between Stokes and anti-Stokes scattering processes, revealing interference phenomena inaccessible to either process alone. Within a dispersive-interaction model beyond the resolved-sideband limit, we show that classical driving and system linewidth coherently links the two channels, enabling phase-controlled interference. Destructive interference induces intrinsic asymmetry in dispersively coupled systems, enabling coherent control of quantum information storage and transfer, while constructive interference leads to exponential signal amplification and thus enhanced quantum detection. This work establishes a unified picture for understanding Stokes-anti-Stokes coherence as a fundamental mechanism underlying both quantum control and metrology. Furthermore, it suggests that these functionalities can be further enhanced by implementing Stokes-anti-Stokes arrays.

Figures (4)

• Figure 1: (a) Schematic diagram of the scattered Stokes and anti-Stokes sidebands in a dispersively coupled system under a classical driving field. Two sidebands are within the mode profile in the unresolved-sideband limit. (b) Quantum interaction between the high- and low-frequency modes and the corresponding diagram of the energy level structure.
• Figure 2: Transmission coefficients $T_{a+}$ and $T_{b+}$ for different dissipation ratios $\kappa_a / \omega_b$: (a) $10^{-2}$, (b) $1$ and (c) $10^2$. The inset in (c) shows the asymmetry factor $\mathcal{R}_{ab}$ for $\kappa_a=10^{2}\omega_b$. (d) $\mathcal{R}_{ab}$ versus $\theta$ for $\kappa_a=\omega_b$ at $\omega=0$ and $\omega=\omega_b$. Other parameters are $\Delta_a = 0$, $G_{ab} = 10^{-1}\omega_b$, $\kappa_b = 10^{-4}\omega_b$, $T = 10\,\mathrm{mK}$, and $\omega_b = 2\pi \times 10\,\mathrm{MHz}$. We set $\psi=0$ in the figure. The effect of the local oscillation phase $\psi$ is analyzed in SMAppendix.
• Figure 3: Asymmetric factors $\mathcal{R}_{mb}$ (red) and $\mathcal{R}_{bc}$ (blue) as functions of the coupling phases $\theta_m$ and $\theta_c$ for (a) $\omega=0$ and (b) $\omega=\omega_b$. Other parameters are $\psi=0$, $\Delta_m=\Delta_c=0$, $G_c=G_m=10^{-1} \omega_b$, $\kappa_c=\kappa_m=\omega_b$, $\kappa_b=10^{-4}\omega_b$, $T=10$ mK, $\omega_b=2 \pi \times 10$ MHz and $\omega_m=2 \pi \times 10$ GHz.
• Figure 4: (a) Density plot of $\lg(f)$ as a function of $\Delta_m$ and $\Delta_c$, where larger values of $f$ correspond to amplified signal in the CS scheme. (b) Logarithmic amplification factor $\lg(S_{\text{AP}})$ as a function of $\Delta_m$ and $\Delta_c$. (c) Comparison of the SNR spectra for the ICS and CS schemes at $\Delta_m = \Delta_c = 0$. Other parameters: $G_c =10^{-1}\omega_b$, $G_m =2\times 10^{-1}\omega_b$, $\kappa_c = 10^{-1}\omega_b$, $\kappa_m = \omega_b$, $\kappa_b = 10^{-4}\omega_b$, $T = 10~\mathrm{mK}$, $\omega_b = 2\pi \times 10~\mathrm{MHz}$ and $\omega_m = 2\pi \times 10~\mathrm{GHz}$.