A Barnett-Like Effect in Relativistic Heavy-Ion Collisions
Abstract
The Barnett effect refers to the spontaneous magnetization or polarization of rotating matter via spin-orbit coupling, a fundamental phenomenon observed across a multitude of physical systems down to atomic scales. Here, we demonstrate that this effect extends to subatomic regimes within relativistic heavy-ion collisions, where the most vortical fluid ever created in terrestrial laboratories is produced and the orbital angular momentum is transferred to emitted hadrons via spin-vorticity coupling. By performing transport simulations spanning a broad energy range, we discover a nearly-linear scaling relation between the global spin polarization of Λ hyperons and the source tilt angle extracted via two-pion femtoscopic correlations. This scaling reveals that global Λ polarization induced by the local vorticity field is modulated by the inclined geometry of the produced strongly-interacting nuclear matter in these collisions. Supported by existing experimental measurements, our results unravel a geometry-modulated Barnett-like effect at the femtometre (10−15 m) scale.
Related
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BibTeX
@misc{liu2026barnettlike,
title = {{A Barnett-Like Effect in Relativistic Heavy-Ion Collisions}},
author = {Dai-Neng Liu and Kai-Jia Sun and Jan Steinheimer and Jin-Hui Chen and Yu-Gang Ma and Marcus Bleicher},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.35310},
eprint = {2610.35310},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.35310},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Barnett-Like Effect in Relativistic Heavy-Ion Collisions
AU - Dai-Neng Liu
AU - Kai-Jia Sun
AU - Jan Steinheimer
AU - Jin-Hui Chen
AU - Yu-Gang Ma
AU - Marcus Bleicher
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.35310
UR - https://arxiv.org/abs/2610.35310
AB - The Barnett effect refers to the spontaneous magnetization or polarization of rotating matter via spin-orbit coupling, a fundamental phenomenon observed across a multitude of physical systems down to atomic scales. Here, we demonstrate that this effect extends to subatomic regimes within relativistic heavy-ion collisions, where the most vortical fluid ever created in terrestrial laboratories is produced and the orbital angular momentum is transferred to emitted hadrons via spin-vorticity coupling. By performing transport simulations spanning a broad energy range, we discover a nearly-linear scaling relation between the global spin polarization of Λ hyperons and the source tilt angle extracted via two-pion femtoscopic correlations. This scaling reveals that global Λ polarization induced by the local vorticity field is modulated by the inclined geometry of the produced strongly-interacting nuclear matter in these collisions. Supported by existing experimental measurements, our results unravel a geometry-modulated Barnett-like effect at the femtometre (10^−15 m) scale.
ER -