Corso di laurea magistrale in Fisica

Numerical simulations based on the regularization on a spacetime lattice remain the only first-priciple approach to derive non-perturbative theoretical predictions for strongly coupled quantum field theories like quantum chromodynamics (QCD), the theory describing the strong nuclear interaction.
In order to minimize discretization effects induced by the finiteness of the lattice spacing a, as well as corrections due to the finiteness of the linear extent L of the system that is simulated, the characteristic length scale of the physical states of interest (such as the Compton wavelength of a particle in the physical spectrum) must be much larger than a and much smaller than L. These constraints force the number of lattice sites to be very large, implying significant costs in terms of memory requirements and simulation time. The problem becomes particularly severe for those problems in which two, or more, widely separated physical scales have to be studied simultaneously: examples range from flavor physics to the behavior of quarkonia within the deconfined medium produced in heavy-ion collision experiments, to composite-Higgs models of potential relevance for physics beyond the Standard Model.
The goal of this thesis project consists in studying a possible solution to this problem, by defining the theory on a sequence of anisotropic lattices, in which the spacing in one direction is different from the others, and iteratively simulate smaller and smaller portions of the system on finer and finer grids, by matching the values of a finite set of physical quantities on given slices of the system.