Extended Data Fig. 4: Uncertainty analysis for frequency-dependent conditional squeezing by means of an effective positive-mass oscillator Ωa/2π = 10.7 kHz at different signal homodyne detection phases (10 out of 18).
From: Hybrid quantum network for sensing in the acoustic frequency range
a, The solid lines represent the inferred quantum noise on the signal detector conditioned on the idler measurement, with the shaded regions indicating the 1σ uncertainty (68% confidence interval). The dashed lines show the quantum noise model fitted to the measured data using a χ2 method. b, The residuals between the measured data and the fitted model, normalized to 1σ uncertainty, are plotted. Noise spikes near 20 kHz (attributed to the etalon dither lock of the 852-nm laser) and classical noise (from both laser intensity noise and magnetic noise sources) at low acoustic frequency (below 10 kHz) are clearly visible in the residual plots.
