How Quantum Is Bottomonium in the Quark-Gluon Plasma?
Abstract
We study how much quantum structure bottomonium retains during its evolution in the quark-gluon plasma. Within the open quantum system framework, we simulate the Lindblad equation obtained from potential nonrelativistic QCD in the quantum Brownian regime. From the resulting real-time evolution of the bottomonium density matrix, we compute the Wigner transform and study its negativity as a measure of nonclassicality and a test of a key condition underlying classical Langevin-type approximations. We find that the medium suppresses the negativity, which nevertheless approaches a finite plateau close to that of the 1S state. The overlaps with the excited 2S and 3S states arise from near-canceling positive and negative phase-space contributions, driven by negative regions in the Wigner transforms of the bound-state projectors, while the 1S overlap is insensitive to such contributions. We further show that the position-space coherence is similarly suppressed and plateaus close to the 1S value. We trace the finite residual quantum structure to conditional purification: the medium preferentially dissolves weakly bound and unbound modes with large ⟨ r2⟩, driving the surviving singlet S-wave ensemble toward the 1S state. More broadly, these results reveal that classicalization is partial and observable dependent, a feature that is relevant across applications of open quantum system methods in fundamental physics.
Related
- General Lindblad equation for quarkonium evolution in a quark-gluon plasma
- Undiscovering Quark-gluon Plasma
- Complex potential and the thermal width of quarkonium in quark-gluon plasma
- Heavy-quark thermalization in the quark-gluon plasma via a fractional Langevin equation
- Complex-energy spectrum and dissociation of heavy quarkonia in an anisotropic collisional quark-gluon plasma
BibTeX
@misc{brambilla2026quantum,
title = {{How Quantum Is Bottomonium in the Quark-Gluon Plasma?}},
author = {Nora Brambilla and Tom Magorsch},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.02313},
eprint = {2610.02313},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.02313},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - How Quantum Is Bottomonium in the Quark-Gluon Plasma?
AU - Nora Brambilla
AU - Tom Magorsch
PY - 2026
DA - 2026/10/01
PB - arXiv
DO - 10.48550/arxiv.2610.02313
UR - https://arxiv.org/abs/2610.02313
AB - We study how much quantum structure bottomonium retains during its evolution in the quark-gluon plasma. Within the open quantum system framework, we simulate the Lindblad equation obtained from potential nonrelativistic QCD in the quantum Brownian regime. From the resulting real-time evolution of the bottomonium density matrix, we compute the Wigner transform and study its negativity as a measure of nonclassicality and a test of a key condition underlying classical Langevin-type approximations. We find that the medium suppresses the negativity, which nevertheless approaches a finite plateau close to that of the 1S state. The overlaps with the excited 2S and 3S states arise from near-canceling positive and negative phase-space contributions, driven by negative regions in the Wigner transforms of the bound-state projectors, while the 1S overlap is insensitive to such contributions. We further show that the position-space coherence is similarly suppressed and plateaus close to the 1S value. We trace the finite residual quantum structure to conditional purification: the medium preferentially dissolves weakly bound and unbound modes with large ⟨ r^2⟩, driving the surviving singlet S-wave ensemble toward the 1S state. More broadly, these results reveal that classicalization is partial and observable dependent, a feature that is relevant across applications of open quantum system methods in fundamental physics.
ER -