Session B3: From Lattice QCD to Nuclear Physics

Saturday, April 16, 2005

I provide an overview of recent attempts to calculate nucleon matrix elements, such as the electromagnetic form-factors and moments of parton distributions, in lattice QCD. Lattice QCD is a numerical approach to solving the field equations of QCD by discretizing space-time and directly integrating the QCD functional integral using Monte-Carlo techniques. As such, lattice calculations enable ab initio investigations of QCD. After introducing lattice QCD and highlighting some current limitations of the approach, I discuss the general principles of calculations of matrix elements. I then focus on recent results for electromagnetic form-factors and the moments of structure functions and generalized parton distributions. I emphasize the experimental relevance of such calculations and the insight they give into the structure of the nucleon. I conclude by discussing prospects for the future.   

Saturday, April 16, 2005

The theory of the strong interactions is 30 years old but has yet to have a substantial impact on our understanding of how nuclei bind. We will discuss the prospects, challenges and recent progress in computing basic nuclear observables using lattice QCD. Some issues of principle will be discussed as well as the beginning of the practical implementation of this programme.   

Saturday, April 16, 2005

We study neutron matter by combining pionless effective field theory with non-perturbative lattice methods. The neutron contact interaction is determined by zero temperature scattering data. We simulate neutron matter on the lattice at temperatures 4 and 8 MeV and densities below one-fifth normal nuclear matter density. Our results at different lattice spacings agree with one another and match bubble chain calculations at low densities. The equation of state of pure neutron matter obtained from our simulations agrees quantitatively with variational calculations based on realistic potentials.