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arXiv:2602.04508 · Quantum Science and Technology

Squeezing-Enhanced Rotational Doppler Metrology

Javier Navarro, Mateo Casariego, Gabriel Molina-Terriza, Íñigo Luis Egusquiza, Mikel Sanz

quant-phSubmitted Feb 4, 2026• Announced Feb 5, 2026• 0 citations
v1 · Feb 4, 2026v2 · Sep 30, 2026
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Abstract

A rotating surface can induce a frequency shift in incident light by changing its angular momentum, a phenomenon known as the rotational Doppler effect. This effect provides a means to estimate the angular velocity of the rotating surface. In this work, we develop a continuous-variable quantum protocol for estimating the angular velocity of a rotating surface via the rotational Doppler effect. Our approach exploits squeezed and displaced Laguerre-Gaussian modes as quantum resources, which interact with a rotating metallic disc with surface roughness. The frequency shift induced by the rotational Doppler effect is then measured using a homodyne detection scheme. By analyzing the Fisher information, we demonstrate that the proposed squeezing-enhanced protocol achieves Heisenberg scaling in the ideal noiseless regime. Furthermore, we investigate the influence of noise and consider different surface models to assess their impact on the protocol's performance. While Heisenberg scaling is degraded in the presence of noise, we show that optimizing the energy allocation ratio between displacement and squeezing of the probe ensures that the quantum strategy consistently outperforms its classical counterpart.

Journal reference
Quantum Sci. Technol. 11(3), 035017 (2026)
DOI
10.1088/2058-9565/ae77e9

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We report on an orbital-angular-momentum-enhanced scheme for angular displacement estimation based on two-mode squeezed vacuum and parity detection. The sub-Heisenberg-limited sensitivity for angular displacement estimation is obtained in an ideal situation. Several realistic factors are also considered, including photon loss, dark counts, response-time delay, and thermal photon noise. Our results indicate that the effects of realistic factors on the sensitivity can be offset by raising orbital angular momentum quantum number ℓ. This implies that the robustness and the practicability of the system can be improved via raising ℓ without changing mean photon number N.
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