nucl-th digest · Jul 14, 2021

QTRAJ 1.0: A Lindblad equation solver for heavy-quarkonium dynamics

We introduce an open-source package called QTraj that solves the Lindblad equation for heavy-quarkonium dynamics using the quantum trajectories algorithm. The package allows users to simulate the suppression of heavy-quarkonium states using externally-supplied input from 3+1D hydrodynamics simulations. The code uses a split-step pseudo-spectral method for updating the wave-function between jumps, which is implemented using the open-source multi-threaded FFTW3 package. This allows one to have manifestly unitary evolution when using real-valued potentials. In this paper, we provide detailed documentation of QTraj 1.0, installation instructions, and present various tests and benchmarks of the code.

Comments:: 35 pages, 10 figures; v2 - minor typos fixed; published version
Subjects:: Computational Physics (physics.comp-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:: 2107.06147 [pdf]

Comput.Phys.Commun.(2022)·39 citations

[Submitted on 13 Jul 2021] (cross-list from hep-ph)

Bottomonium production in heavy-ion collisions using quantum trajectories: Differential observables and momentum anisotropy

Nora Brambilla🇩🇪 · Miguel Ángel Escobedo🇪🇸 · Michael Strickland🇺🇸 · Antonio Vairo🇩🇪 · Peter Vander Griend🇩🇪 · Johannes Heinrich Weber🇺🇸

We report predictions for the suppression and elliptic flow of the $Υ (1 S)$ , $Υ (2 S)$ , and $Υ (3 S)$ as a function of centrality and transverse momentum in ultra-relativistic heavy-ion collisions. We obtain our predictions by numerically solving a Lindblad equation for the evolution of the heavy-quarkonium reduced density matrix derived using potential nonrelativistic QCD and the formalism of open quantum systems. To numerically solve the Lindblad equation, we make use of a stochastic unraveling called the quantum trajectories algorithm. This unraveling allows us to solve the Lindblad evolution equation efficiently on large lattices with no angular momentum cutoff. The resulting evolution describes the full 3D quantum and non-abelian evolution of the reduced density matrix for bottomonium states. We expand upon our previous work by treating differential observables and elliptic flow; this is made possible by a newly implemented Monte-Carlo sampling of physical trajectories. Our final results are compared to experimental data collected in $s_{N N} = 5.02$ TeV Pb-Pb collisions by the ALICE, ATLAS, and CMS collaborations.

Comments:: 14 pages, 11 figures
Subjects:: High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
arXiv:: 2107.06222 [pdf]

PRD(2021)·71 citations

Wednesday·July 14, 2021

QTRAJ 1.0: A Lindblad equation solver for heavy-quarkonium dynamics

Bottomonium production in heavy-ion collisions using quantum trajectories: Differential observables and momentum anisotropy

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