Hypersurface covariance in relativistic local equilibrium
Abstract
Defining equilibrium typically requires specifying a three-dimensional spacelike hypersurface. While global equilibrium is hypersurface covariant, calculations involving local equilibrium can exhibit hypersurface dependence. In this work, we use polarization in heavy-ion collisions within the Zubarev response approach as an example to show that the hypersurface dependence arising from the local-equilibrium part of the density operator is canceled by an overlooked nondissipative contribution from its so-called ``dissipative part". We establish a hypersurface-covariant Zubarev framework for general geometries by consistently including both nondissipative and dissipative parts, eliminating dependence on the arbitrary hypersurface vector. The remaining frame dependence is physical: it arises from the medium rest frame entering the particle distribution and the time direction of the dissipative process, which usually coincide. This resolves, in principle, the longstanding and widely discussed conceptual disagreement over hypersurface dependence between two influential studies addressing the sign puzzles of Λ-hyperon polarization in heavy-ion collisions
Related
- Relativistic Covariance from Hamiltonian Hydrodynamics in the Chiral Limit
- Finite-Distance Imaging of Relativistic Equilibrium Tori around Genuine Kerr--Bertotti--Robinson Black Holes
- Multiconfigurational Analysis of Local Electronic Structure of RuO2 Using Relativistic Embedded Clusters
- Local micromechanics in a mean-field model of glasses reveal key properties of its non-equilibrium RSB phase
- Optimization of a deformable mirror using covariance matrix adaptation evolution strategy.
BibTeX
@misc{li2026hypersurface,
title = {{Hypersurface covariance in relativistic local equilibrium}},
author = {You-yu Li and Shuai Y. F. Liu},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.08482},
eprint = {2611.08482},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.08482},
}
RIS
TY - UNPB
TI - Hypersurface covariance in relativistic local equilibrium
AU - You-yu Li
AU - Shuai Y. F. Liu
PY - 2026
DA - 2026/11/05
PB - arXiv
DO - 10.48550/arxiv.2611.08482
UR - https://arxiv.org/abs/2611.08482
AB - Defining equilibrium typically requires specifying a three-dimensional spacelike hypersurface. While global equilibrium is hypersurface covariant, calculations involving local equilibrium can exhibit hypersurface dependence. In this work, we use polarization in heavy-ion collisions within the Zubarev response approach as an example to show that the hypersurface dependence arising from the local-equilibrium part of the density operator is canceled by an overlooked nondissipative contribution from its so-called ``dissipative part". We establish a hypersurface-covariant Zubarev framework for general geometries by consistently including both nondissipative and dissipative parts, eliminating dependence on the arbitrary hypersurface vector. The remaining frame dependence is physical: it arises from the medium rest frame entering the particle distribution and the time direction of the dissipative process, which usually coincide. This resolves, in principle, the longstanding and widely discussed conceptual disagreement over hypersurface dependence between two influential studies addressing the sign puzzles of Λ-hyperon polarization in heavy-ion collisions
ER -