Thesis

Intertwinement between entanglement and the QCD flux tube

• Call:

  IDPASC Portugal - PHD Programme 2019

• Academic Year:

  2019 / 2020

• Domain:

  Theoretical Particle Physics

• Supervisor:

  Orlando Oliveira

• Co-Supervisor:

  David Dudal

• Institution:

  Universidade de Coimbra

• Host Institution:

  Universidade de Coimbra

• Abstract:

  Quantum entanglement can be interpreted as the extent that the quantum state of one system A is depending on that of the rest of the system B. It can be quantified by the entanglement entropy (EE) of A relative to B, a generalization of the usual concept of (thermal) entropy. We are interested in the QCD flux tube connecting a quark and antiquark. This picture is realized in the non-perturbative dual superconductor scenario of the QCD vacuum, and it naturally leads to a linear and thus confining potential between the static quarks. Lattice QCD has shown that EE is sensitive to (de)confinement, on a par with predictions from holography (AdS/QCD). This is solely verified for the infinite strip geometry. On one hand, research in (holographic) superconductivity has unveiled that EE is also sensitive to the transition between the superconductor--normal state. On the other hand, (old) lattice work in a 3D QCD toy model has given partial evidence that inside the color-electric flux tube binding the quarks together, a normal perturbative vacuum state emerges. We want to first verify this picture from state of the art 4D QCD- simulations, after which we can turn to the 1st ever study of how the (inside of the) flux tube is entangled with the outside. We conjecture this can be probed by studying the lattice EE of a cylinder placed around the flux tube. From the response of the EE to the radius of the cylinder, we might even quantify the thickness of the flux tube.