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arXiv · 2609.25673

Post-selected enhancement of phase sensitivity in a two-path interferometer

Ryuya Fukuda·Katsuki Tanaka·Masataka Iinuma·Holger F. Hofmann
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Abstract

Post-selected metrology can exceed the standard quantum limit of single photon interference by concentrating all of the available Fisher information in a subset of post-selected outcomes. Here we apply this principle to a standard two-path interferometer, activating the Fisher information concentrated in the low probability output port by transferring the phase sensitivity to the circular polarizations of the photon. We obtain a phase gradient of the post-selected interference fringe that corresponds to that of a four-photon NOON state, providing a direct comparison of the performance of multi-photon interference with single-photon post-selection.

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Ryuya Fukuda, Katsuki Tanaka, Masataka Iinuma, Holger F. Hofmann. 2026-09-22. Post-selected enhancement of phase sensitivity in a two-path interferometer. https://arxiv.org/abs/2609.25673

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