FROM COMPLEX TO STOCHASTIC POTENTIAL: HEAVY QUARKONIA IN THE QUARK–GLUON PLASMA

The in-medium physics of heavy quarkonium is an ideal proving ground for our ability to connect knowledge about the fundamental laws of physics to phenomenological predictions. One possible route to take is to attempt a description of heavy quark bound states at finite temperature through a Schrödinger equation with an instantaneous potential. Here we review recent progress in devising a comprehensive approach to define such a potential from first principles QCD and extract its, in general complex, values from non-perturbative lattice QCD simulations. Based on the theory of open quantum systems we will show how to interpret the role of the imaginary part in terms of spatial decoherence by introducing the concept of a stochastic potential. Shortcomings as well as possible paths for improvement are discussed.

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Quarkonia dynamics in the QGP with open quantum systems

EPJ Web of Conferences ◽

10.1051/epjconf/202225805009 ◽

2022 ◽

Vol 258 ◽

pp. 05009

Author(s):

Stéphane Delorme ◽

Thierry Gousset ◽

Roland Katz ◽

Pol-Bernard Gossiaux

Keyword(s):

Real Time ◽

Quark Gluon Plasma ◽

Open Quantum Systems ◽

Gluon Plasma ◽

Quantum Systems ◽

Master Equations ◽

Temperature Evolution ◽

One Dimension ◽

Initial State ◽

Time Dynamics

We investigate the real-time dynamics of a correlated heavy quarkantiquark pair inside the Quark-Gluon Plasma using new quantum master equations derived from first QCD principles and based on the work of Blaizot & Escobedo [4]. The full equations are directly numerically solved in one-dimension to reduce computing costs and is used to gain insight on the dynamics in both a static and evolving medium following a Björken-like temperature evolution. The effect of the initial state on the dynamics is also studied.

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Heavy Quarkonium Properties at Finite Temperature in Strongly Coupled Quark Gluon Plasma

Few-Body Systems ◽

10.1007/s00601-021-01592-6 ◽

2021 ◽

Vol 62 (1) ◽

Author(s):

K. T. Rethika ◽

C. D. Ravikumar ◽

Vishnu M. Bannur

Keyword(s):

Quark Gluon Plasma ◽

Finite Temperature ◽

Gluon Plasma ◽

Heavy Quarkonium ◽

Strongly Coupled

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Local Spin and Open Quantum Systems: Clarifying Misconceptions, Unifying Approaches

10.26434/chemrxiv.13200245.v1 ◽

2020 ◽

Author(s):

Angel Martín Pendás ◽

Evelio Francisco

Keyword(s):

Quantum Control ◽

Open Systems ◽

Open Quantum Systems ◽

Real Space ◽

Quantum Systems ◽

Spin Coupling ◽

Molecular Systems ◽

Open Quantum ◽

Local Spin

We now show that Clark and Davidson local spins operators are perfectly defined subsystem operators if a fragment is taken as an open quantum system (OQS). Open systems have become essential in quantum control and quantum computation, but have not received much attention in Chemistry. We have already shown (J. Chem. Theory Comput. 2018, 15, 1079) how real space OQSs can be defined in molecular systems and how they offer new insights relating quantum mechanical entaglement and chemical bonding. The OQS account of local spin that we offer yields a rigorous, yet easily accessible way to rationalize local spin values. A fragment is found in a mixed state direct sum of sectors characterized by different number of electrons that occur with different probabilities. The local spin is then a weighted sum of otherwise standard S(S+1) values. With OQS glasses, it is obvious that atomic or fragment spins should not vanish. Our approach thus casts doubts on any procedure used to annihilate them, like those used by Mayer and coworkers. OQS local spins allow for a fruitful use of models. One can propose easily sector probabilities for localized, covalent, ionic, zwitterionic, etc. situations, and examine their ideal local spins. We have mapped all 2c-2e cases, and shown how to do that in general multielectron cases. The role of electron correlation is also studied by tuning the Hubbard U/t parameter for H chains. Correlation induced localization changes the spin-coupling patterns even qualitatively, and show how the limiting antiferromagnet arises.

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