Chasing deconfinement with lattice QCD simulations

This project aims to improve our current understanding of confinement and deconfinement using lattice QCD simulations. Confinement refers to the fact that color charged particles like quarks and gluons can not be isolated. However, for high temperatures and densities, hadronic matter undergoes a phase transition to a quark-gluon plasma, where gluons and quarks behave as massive free particles. The current heavy-ion experiments at CERN and RHIC motivate further studies of the dynamics of QCD at finite temperature and density. In this project we will pursue an investigation of the mechanism of confinement and deconfinement using lattice QCD simulations. This will be done through the computation of Polyakov loop potentials, string tension and flux tubes. We also aim to study the Landau gauge gluon, ghost, and quark propagators at finite temperature, using dynamical simulations, to identify signs of deconfinement in the propagators. Lattice QCD is one of the most successful approaches to understand Quantum Chromodynamics (QCD), in particular its non-perturbative regime. Indeed, a space-time lattice provides a natural regulator of the theory which, together with the imaginary time formalism, allows for simulating QCD in a computer. In fact, Lattice QCD operates at the edge of supercomputer technology. Ideally we should be able to compute infinite-dimensional integrals, but with Monte Carlo techniques we simplify the computations to a finite dimensional integrals, with number of dimensions of the order of 1000000000. With the path integral formalism, the dimension of the integral is the number of space-time points - infinite in the continuum - times the dimension of the internal symmetry groups. This requires writing very efficient computer codes, and running them in the fastest computers. In Portugal, the lattice QCD community is organized in the PtQCD collaboration. We have two nodes, hosted by Centro de Física Teórica de Partículas at Instituto Superior Técnico, University of Lisboa, and CFisUC, former CFC, at Faculty of Sciences and Technology, University of Coimbra. This collaboration was first funded in 2005 by the FCT grant PDCT/FP/63923/2005, and since then we have been developing our lattice QCD know-how and equipment, and forming several young bright students not only in quantum physics but also in supercomputing.

Status: Running

Starting date: 1/Nov/2018

End date: 31/Oct/2020

Financing: 10000 euros Euros

Financing entity: FCT (Fundo CERN)

Project ID: CERN/FIS-COM/0029/2017

Person*month: 0

Group person*month: 0