Auto-correlative weak-value amplification under strong noise background

TL;DR

This paper introduces the auto-correlative weak-value amplification (AWVA) method, which enhances measurement precision in noisy environments by using auto-correlation of Gaussian pulses, outperforming standard WVA in strong noise conditions.

Contribution

The paper proposes a novel AWVA protocol that improves weak measurement sensitivity under strong noise by measuring auto-correlation instead of mean shifts.

Findings

AWVA outperforms standard WVA in noisy conditions

AWVA achieves higher precision with smaller statistical errors

Simulation confirms robustness of AWVA against strong Gaussian white noise

Abstract

By choosing more orthogonality between pre-selection and post-selection states, one can significantly improve the sensitivity in the general optical quantum metrology based on the weak-value amplification (WVA) approach. However, increasing the orthogonality decreases the probability of detecting photons and makes the weak measurement difficult, especially when the weak measurement is disturbed by strong noise and the pointer is drowned in noise with a negative-dB signal-to-noise ratio (SNR). In this article, we investigate a modified weak measurement protocol with a temporal pointer, namely, the auto-correlative weak-value amplification (AWVA) approach. Specifically, a small longitudinal time delay (tiny phase shift) $\tau$ of a Gaussian pulse is measured by implementing two simultaneous auto-correlative weak measurements under Gaussian white noise with different SNR. The small quantities $\tau$ are obtained by measuring the auto-correlation coefficient of the pulses instead of fitting the shift of the mean value of the probe in the standard WVA technique. Simulation results show that the AWVA approach outperforms the standard WVA technique in the time domain with smaller statistical errors, remarkably increasing the precision of weak measurement under strong noise background.