Quantum Localization Limit of Transport-Based Femtoscopy
Abstract
Femtoscopic correlations in proton-proton and heavy ion collisions are commonly calculated using emission sources from microscopic transport models, where emitted particles are represented by classical phase-space points with simultaneously specified positions and momenta. This point-emitter picture neglects the finite phase-space localization required by quantum mechanics, which can become relevant when the localization scale approaches the femtoscopic source size, particularly in small collision systems. We formulate a quantum treatment by replacing each transport phase-space point with a minimum-uncertainty Gaussian phase-space distribution. Finite localization then induces both spatial and momentum smearing; in the presence of coordinate-momentum correlations, the latter produces a nontrivial modification of the emission source. Using proton--proton collisions at √s=7 TeV simulated with the microscopic Parton--Hadron--String Dynamics transport approach, we show that this effect significantly modifies the proton-pair source and its momentum correlation. Our results expose a quantum localization effect overlooked in transport-based femtoscopy and establish the regime in which the classical point-emitter approximation is valid.
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BibTeX
@misc{zhao2026quantum,
title = {{Quantum Localization Limit of Transport-Based Femtoscopy}},
author = {Jiaxing Zhao and Joerg Aichelin and Elena Bratkovskaya},
howpublished = {HAL},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10892},
eprint = {2610.10892},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05829954v1},
note = {CC0},
}
RIS
TY - UNPB
TI - Quantum Localization Limit of Transport-Based Femtoscopy
AU - Jiaxing Zhao
AU - Joerg Aichelin
AU - Elena Bratkovskaya
PY - 2026
DA - 2026/10/07
PB - HAL
DO - 10.48550/arxiv.2610.10892
UR - https://hal.science/hal-05829954v1
AB - Femtoscopic correlations in proton-proton and heavy ion collisions are commonly calculated using emission sources from microscopic transport models, where emitted particles are represented by classical phase-space points with simultaneously specified positions and momenta. This point-emitter picture neglects the finite phase-space localization required by quantum mechanics, which can become relevant when the localization scale approaches the femtoscopic source size, particularly in small collision systems. We formulate a quantum treatment by replacing each transport phase-space point with a minimum-uncertainty Gaussian phase-space distribution. Finite localization then induces both spatial and momentum smearing; in the presence of coordinate-momentum correlations, the latter produces a nontrivial modification of the emission source. Using proton--proton collisions at √s=7 TeV simulated with the microscopic Parton--Hadron--String Dynamics transport approach, we show that this effect significantly modifies the proton-pair source and its momentum correlation. Our results expose a quantum localization effect overlooked in transport-based femtoscopy and establish the regime in which the classical point-emitter approximation is valid.
ER -