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arXiv · 2605.00331

Toward Heisenberg-Limited Interferometry with Dual Squeezers

Yi Gu·Song-Ping Wang·Wei Zhong
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Abstract

The canonical Mach-Zehnder interferometer fed with a coherent state and a squeezed-vacuum state of equal intensities is theoretically predicted to achieve Heisenberg scaling in phase sensitivity. However, this ultimate performance is unattainable using direct photon-number-difference detection due to a divergence arising precisely at the optimal equal-intensity regime. In this work, we introduce a dual-squeezing approach that overcomes this fundamental limitation. Our scheme employs an additional single-mode squeezer before detection, forming a paired configuration with the input squeezer used to generate the squeezed-vacuum state. We analytically demonstrate that the resulting dual-squeezing Mach-Zehnder interferometer enables Heisenberg-limited phase sensitivity with di rect photon-number-difference detection, while remaining robust against detection noise. Our work provides a feasible and robust route toward quantum-limited interferometric phase measurements

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Yi Gu, Song-Ping Wang, Wei Zhong. 2026-05-01. Toward Heisenberg-Limited Interferometry with Dual Squeezers. https://arxiv.org/abs/2605.00331

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