Real-time analog circuit for auto-correlative weak-value amplification in the time domain

Abstract: The auto-correlative weak-value amplification (AWVA) technique demonstrates distinct advantages over standard weak-value amplification (SWVA) for quantum parameter estimation. To achieve enhanced precision in real-time parameter estimation, the AWVA requires additional resources compared to SWVA, namely real-time multiplication and integrator modules. We implemented a real-time analog circuit for AWVA using an AD835 multiplier and an NE5532 operational amplifier for the integrator. The circuit was tested using Gaussian pointers in the AWVA scheme, exhibiting sufficient sensitivity for Gaussian pointers with frequencies 200 Hz < f < 20kHz. Compared to SWVA, AWVA achieves higher accuracy and superior robustness against noise at signal-to-noise ratios (SNRs) of -12 dB < SNR < -4 dB. Beyond quantum metrology, the circuit is applicable to diverse detection schemes for correlated signals.