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arXiv · 2509.02296

Optimal distillation of photonic indistinguishability

Francesco Hoch·Anita Camillini·Giovanni Rodari·Eugenio Caruccio·Gonzalo Carvacho·Taira Giordani·Riccardo Albiero·Niki Di Giano·Giacomo Corrielli·Francesco Ceccarelli·Roberto Osellame·Marco Robbio·Leonardo Novo·Nicolò Spagnolo·Ernesto F. Galvão·Fabio Sciarrino
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Abstract

Imperfect photons' indistinguishability limits the performance of photonic quantum communication and computation . Distillation protocols, inspired by entanglement purification, enhance photons' indistinguishability by leveraging quantum interference in linear optical circuits. In this work, we present a three-photon distillation protocol optimized to achieve the maximum visibility gain, which requires consideration of multi-photon effects such as collective photonic phases. We employ interferometers with the minimum number of modes, optimizing also over the protocol's success probability. The developed protocol is experimentally validated with a platform featuring a demultiplexed quantum dot source interfaced with a programmable eight-mode laser-written integrated photonic processor. We achieve indistinguishability distillation with limited photonic resources and for several multi-photon distinguishability scenarios. This work helps to strengthen the role of distillation as a practical tool for photon-based quantum technologies.

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Francesco Hoch, Anita Camillini, Giovanni Rodari, Eugenio Caruccio, Gonzalo Carvacho, Taira Giordani, Riccardo Albiero, Niki Di Giano, Giacomo Corrielli, Francesco Ceccarelli, Roberto Osellame, Marco Robbio, Leonardo Novo, Nicolò Spagnolo, Ernesto F. Galvão, Fabio Sciarrino. 2025-09-02. Optimal distillation of photonic indistinguishability. https://arxiv.org/abs/2509.02296

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