Thesis

Understanding non-perturbative QCD via computer simulations on a spacetime lattice

• Call:

  IDPASC Portugal - PHD Programme 2014

• Academic Year:

  2014 /2015

• Domain:

  Theoretical Particle Physics

• Supervisor:

  Orlando Oliveira

• Co-Supervisor:

  Paulo Silva

• Institution:

  Universidade de Coimbra

• Host Institution:

• Abstract:

  Experimentally, free quarks or gluons were never observed. This empirical fact is called confinement and it is a manifestation of the non-perturbative regime of QCD. The perturbative solution of Quantum Chromodynamics is unable to accommodate confinement and other "non-perturbative" features associated with the theory. The formulation of QCD on a spacetime lattice allows to access its non-perturbative dynamics from first principles, by means of computer simulations. However, any simulation is plagued with finite volume and finite lattice spacing effects which have to be removed for a reliable determination of the quantities of interest. The computation of the correlation functions of the fundamental fields is an important task still to be finished using lattice simulations. The correlation functions encode the full dynamics of QCD. In a recent past, some basic Green's functions, such as gluon, ghost and quark propagators, have been studied by several research groups. However, the removal of lattice artifacts still remains to be done in a systematic way. The project, to be developed in collaboration with the lattice QCD group at the University of Lisbon, aims to compute the quark propagator and quark-gluon vertex free of lattice artifacts at zero and at finite temperature. The project will profit from the new high performance computer facilities currently under instalation at the University of Coimbra and computer time available through PRACE projects. These correlation functions encode the non-perturbative nature of QCD related to the confinement and chiral symmetry breaking mechanisms. Furthermore, they are important correlation functions to be used in Dyson-Schwinger and Bethe-Salpeter equations to access relevant phenomenological properties of hadrons. It is therefore of paramount importance to have access to good quality data for the correlation functions free of lattice artifacts.