Hadronic interactions and nuclear physics

Abstract

I give an overview of efforts in the last year to calculate interactions among hadrons using lattice QCD. Results discussed include the extraction of low-energy phase shifts and three-body interactions, and the study of pion and kaon condensation. A critical appraisal is offered of recent attempts to calculate nucleon-nucleon and nucleon-hyperon potentials on the lattice.

Simulating QCD at finite density

“…This is a very important and active research direction, reviewed last year [53], with two large-scale efforts underway [54,55]. The sign problem appears in the form of a signal-to-noise ratio for baryon correlators degrading exponentially fast in Euclidean time [56].…”

Hadron interactions in lattice QCD

“…Ref. [18,25,26], however, criticized that the NBS wave function is not "the correct wave function for two nucleons" and that its 1 It is more legitimated to show if three or more body potentials remain subdominant in the same framework in QCD before using the potential in nuclear physics. There exists another approach to investigate nuclei, by combining the chiral effective field theory with lattice calculations.…”

Uncertainty quantification of effective nuclear interactions

“…Using sub-nuclear degrees of freedom in terms of quarks and gluons it is possible, in principle, to describe all levels of hadronic interactions up to nuclear binding. However, despite the tremendous effort done in direct lattice QCD calculations [18][19][20] this approach still falls short when confronted with NN scattering data (see however the recent development 21 ). Other indirect approaches with QCD ingredients like the inclusion of chiral symmetries in Effective Field Theory (EFT) [22][23][24][25][26][27][28] or large number of colors N c scaling for the NN potential [29][30][31][32][33] either have a phenomenological component or are unable to accurately reproduce NN scattering observables as high quality interactions up to energies near the pion production threshold (see the discussions in Refs.…”