Imaging Walk-Off Driven Distortions in EPR Photon Pair Correlations

Fuente: arXiv
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Main Authors: Howard, Christian, Ghobadi, Roohollah, Dehghan, Nazanin, D'Errico, Alessio, Karimi, Ebrahim
Format: Preprint
Published: 2025
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_version_ 1866912762283687936
author Howard, Christian
Ghobadi, Roohollah
Dehghan, Nazanin
D'Errico, Alessio
Karimi, Ebrahim
author_facet Howard, Christian
Ghobadi, Roohollah
Dehghan, Nazanin
D'Errico, Alessio
Karimi, Ebrahim
contents Spontaneous parametric down-conversion is the primary source of position-correlated and momentum-anticorrelated photon pairs that form the canonical Einstein-Podolsky-Rosen (EPR) state. Their transverse spatial correlations are usually analyzed within the thin-crystal approximation, where the two-photon wavefunction is assumed to factorize into independent functions of the sum and difference coordinates. In practice, however, birefringence-induced transverse walk-off breaks this factorization and couples these degrees of freedom. Here, we show that this coupling persists even for nominally thin crystals once the free-space propagation of the joint spatial intensity is taken into account. This sum-difference coordinate coupling leads to a distinctive tapering of the transverse correlations near the crystal image plane-an effect that standard factorized models cannot capture. Numerical simulations and experimental data clearly confirm this novel behavior. Our findings provide a more complete description of photon-pair generation in birefringent nonlinear media and clarify fundamental limits on spatially resolved quantum imaging and spatial-mode quantum information processing with EPR states.
format Preprint
id arxiv_https___arxiv_org_abs_2512_12423
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Imaging Walk-Off Driven Distortions in EPR Photon Pair Correlations
Howard, Christian
Ghobadi, Roohollah
Dehghan, Nazanin
D'Errico, Alessio
Karimi, Ebrahim
Quantum Physics
Spontaneous parametric down-conversion is the primary source of position-correlated and momentum-anticorrelated photon pairs that form the canonical Einstein-Podolsky-Rosen (EPR) state. Their transverse spatial correlations are usually analyzed within the thin-crystal approximation, where the two-photon wavefunction is assumed to factorize into independent functions of the sum and difference coordinates. In practice, however, birefringence-induced transverse walk-off breaks this factorization and couples these degrees of freedom. Here, we show that this coupling persists even for nominally thin crystals once the free-space propagation of the joint spatial intensity is taken into account. This sum-difference coordinate coupling leads to a distinctive tapering of the transverse correlations near the crystal image plane-an effect that standard factorized models cannot capture. Numerical simulations and experimental data clearly confirm this novel behavior. Our findings provide a more complete description of photon-pair generation in birefringent nonlinear media and clarify fundamental limits on spatially resolved quantum imaging and spatial-mode quantum information processing with EPR states.
title Imaging Walk-Off Driven Distortions in EPR Photon Pair Correlations
topic Quantum Physics
url https://arxiv.org/abs/2512.12423