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arXiv · 2606.19649

Optimized Quantum States for Sensing in the Presence of Loss and Phase Noise

Shruti Maliakal·Zachary Mann·Christopher Wipf·Rana X Adhikari·Su Direkci·Yanbei Chen
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Abstract

Squeezed vacuum lets gravitational-wave detectors and other quantum sensors surpass the standard quantum limit, and is optimal in the loss-limited regime; phase noise breaks this optimality. Numerically optimizing the quantum Fisher information across the loss and phase-noise landscape, we identify non-Gaussian states that outperform any Gaussian state. These fall into three classes: Fock-like, cubic-phase-like, and states with discrete rotational symmetry. Limiting the average number of photons in the input state to $\bar{n}=5$, with $1-\eta = 5\%$ photon loss and 200 mrad phase noise, the non-Gaussian advantage reaches up to 2.2 dB. Furthermore, we observe that the non-Gaussian advantage can persist even when the measurement strategy is homodyne detection.

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Shruti Maliakal, Zachary Mann, Christopher Wipf, Rana X Adhikari, Su Direkci, Yanbei Chen. 2026-06-17. Optimized Quantum States for Sensing in the Presence of Loss and Phase Noise. https://arxiv.org/abs/2606.19649

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