Effective field theory in finite volume

  Moti Elyahu  ,  Nir Barnea  
Hebrew University of Jerusalem

At low energies characterizing the nuclear structure, Quantum Chromo Dynamics (QCD), the basic theory of the strong interactions, is non-perturbative. The only viable way to obtain ab-initio QCD predictions for nuclear physics is through Lattice simulations (LQCD). In the last decade, LQCD started to yield reliable predictions of few baryon systems. The LQCD calculations are done discretizing space time in a finite box and extrapolating to infinite volume. These calculation are usually done for unnaturally heavy quarks serving as “experimental” environment for studying the quark mass dependence of light nuclei.

In this research we use nuclear Effective Fields Theory (EFT), designed to provide a low energy description of QCD using baryonic degrees of freedom, to study LQCD results. The goal of this research is developing a method for calculating nuclear observables in finite volume using EFT.  Calculations based on effective theory combined with the ability to study few baryon systems in a box would, (i) allow direct calibration of the LQCD data, avoiding infinite volume extrapolation, (ii) will allow making theoretical predictions to be compared directly with LQCD simulations, (iii) Might allow for LQCD calculation to be performed in a small volumes – improving accuracy and lowering costs, (iv) be much faster and cheaper than LQCD simulations, (v) can be used to extended LQCD predictions to larger systems and different observables. So far we studied the model case of two and three-particles, bosons and fermions, with two and three-body interaction in a cubic box with periodic boundary conditions