English

Distributed Phase Sensing with Multiphoton States in Optical Interferometry

Quantum Physics 2026-08-04 v1

Abstract

We investigate interferometric phase-estimation using separable photon inputs that evolve into number-path entangled states through linear optical networks, followed by photon-number-resolving detection. A simple analytical expression for the classical Fisher information at zero phase is derived for arbitrary NN-photon states distributed across 2NN optical modes, partitioned into phase-encoding and reference blocks. Among all possible photon distributions between these blocks, the balanced configuration maximizes the phase sensitivity for every photon number NN and uniquely exhibits a phase-independent response. The achievable sensitivity degrades monotonically with increasing asymmetry in the photon distribution. We further investigate the robustness of the protocol in the presence of realistic photon loss and extend the analysis to distributed architectures with multiple receivers. In the low photon-flux regime, vacuum fluctuations fundamentally limit local quadrature measurements, whereas nonlocal photon-number-resolving measurements exploit multiphoton interference to mitigate loss-induced sensitivity degradation. Together, these results establish a scalable framework for quantum-enhanced distributed multimode metrology.

Cite

@article{arxiv.2608.02977,
  title  = {Distributed Phase Sensing with Multiphoton States in Optical Interferometry},
  author = {Subhrajit Modak and Danilo Triggiani and Cosmo Lupo},
  journal= {arXiv preprint arXiv:2608.02977},
  year   = {2026}
}

Comments

17 pages, 4 figures