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arXiv · 2512.08458

Heralded generation of a three-mode NOON state

Sukhjit P. Singh·Elnaz Bazzazi·Diego N. Bernal-García·Simon White·Hassan Jamal Latief·Alison Goldingay·Sven Rogge·Sergei Slussarenko·Farzad Ghafari·Emanuele Polino·Nora Tischler
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Abstract

Entangled states of photons form the foundation of quantum communication, computation, and metrology. Yet their generation remains fundamentally constrained: in the absence of intrinsic photon-photon interactions, the generation of such states is inherently probabilistic rather than deterministic. The prevalent technique of post-selection verifies the creation of an entangled state by detecting and thus destroying it. Heralding offers a solution in which measuring ancillary photons in auxiliary modes signals the state generation without the need to measure it. Here, we introduce and experimentally demonstrate a scheme to generate a three-mode two-photon NOON state, where the detection of a single photon in one heralding mode signifies the presence of the state in three target modes. We validate the generated state by estimating a fidelity of 0.823 +/- 0.018 with respect to an ideal three-mode NOON state and certifying genuine multipartite entanglement. By virtue of the high success probability and small resource overhead of our scheme, our work provides a theoretical and experimental stepping stone for entangled multi-mode state generation, which is realizable with current technology. These multi-mode entangled states represent a key direction for linear optical quantum information that is complementary to multi-qubit state encoding.

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Sukhjit P. Singh, Elnaz Bazzazi, Diego N. Bernal-García, Simon White, Hassan Jamal Latief, Alison Goldingay, Sven Rogge, Sergei Slussarenko, Farzad Ghafari, Emanuele Polino, Nora Tischler. 2025-12-09. Heralded generation of a three-mode NOON state. https://arxiv.org/abs/2512.08458

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