Windowed Catodyne Measurements: Continuum Approximation versus Exact Discrete Photon-Number Treatment
Abstract
We analyze a family of measurements obtained by retaining only a finite window of the photon-sum variable in catodyne detection, where a Schrödinger cat state serves as the local oscillator. In the continuum approximation, the window half-width appears to act as a continuous knob for coherence. However, a treatment on the discrete photon-number lattice shows that, in the strong-LO regime, the coherence conditioned on the difference outcome is not suppressed by the window. The exact parity-sensitive success probability is a staircase function of and , whose plateau structure and magnitude the continuum formulas fail to capture, especially for small and narrow windows. For remote preparation of cat states, an exact calculation with a finitely squeezed resource shows that the remote state keeps a purity close to one when x is resolved, and loses purity mainly when x is not recorded. Our results clarify where the continuum approximation of catodyne detection can be trusted and where the discrete photon-number structure must be used.
Related
- Doublon bound states in the continuum through giant atoms
- Topologically protected bound states in the continuum in the Su-Schrieffer-Heeger chain
- Direct observation of the Lindhard continuum using resonant inelastic X-ray scattering
- Dimension-dependent continuum limits in tissue mechanics
- Discontinuity of Continuum Fermion Dynamics
BibTeX
@misc{nahvifard2026windowed,
title = {{Windowed Catodyne Measurements: Continuum Approximation versus Exact Discrete Photon-Number Treatment}},
author = {Elahe Nahvifard and Mohammad Reza Bazrafkan},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.41626},
eprint = {2610.41626},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.41626},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Windowed Catodyne Measurements: Continuum Approximation versus Exact Discrete Photon-Number Treatment
AU - Elahe Nahvifard
AU - Mohammad Reza Bazrafkan
PY - 2026
DA - 2026/10/30
PB - arXiv
DO - 10.48550/arxiv.2610.41626
UR - https://arxiv.org/abs/2610.41626
AB - We analyze a family of measurements obtained by retaining only a finite window of the photon-sum variable in catodyne detection, where a Schrödinger cat state serves as the local oscillator. In the continuum approximation, the window half-width appears to act as a continuous knob for coherence. However, a treatment on the discrete photon-number lattice shows that, in the strong-LO regime, the coherence conditioned on the difference outcome is not suppressed by the window. The exact parity-sensitive success probability is a staircase function of and , whose plateau structure and magnitude the continuum formulas fail to capture, especially for small and narrow windows. For remote preparation of cat states, an exact calculation with a finitely squeezed resource shows that the remote state keeps a purity close to one when x is resolved, and loses purity mainly when x is not recorded. Our results clarify where the continuum approximation of catodyne detection can be trusted and where the discrete photon-number structure must be used.
ER -