Lattice QCD is a set of sophisticated numerical techniques that us to compute the effects of the strong interaction of particle physics that binds quarks and gluons (some of the fundamental particles of the Standard Model) together into protons and neutrons and then in to nuclei. Lattice QCD was invented in the 1970s by Nobel laureate Kenneth Wilson shortly after the theory of quantum chromodynamics was discovered. Lattice QCD provides a rigorous definition of QCD as it is defined for all values of the coupling strength of QCD and is also amenable to numerical solution. At intermediate stages the method compactifies and discretises spacetime on a four dimensional hypercube, with final results emerging in the limit that the discretisation scale is taken to zero and the volume is taken to infinity. Physical quantities are determined by integrals over the possible configurations of quark and gluon degrees of freedom on the spacetime lattice. While too high dimensioned to be evaluated by quadrature methods, thesse integrals are ammenable to importance sampling Monte Carlo algorithms that provide rigorous estimates for such quantities with controlled, and systematically improvable, uncertainties. Our group utilises the worlds fastest supercomputers such as Mira, Summit and Stampde to do this and solve frontier problems in nuclear and particle physics.
Detmold, Murphy, Shanahan and Wagman are members of the multi-institutional NPLQCD Collaboration whose focus is studying nuclear structure from first principles using LQCD.
Negele and Pochinsky are memebers of the Lattice Hadron Physics Collaboration, focusing on the study of the structure of the proton.
All our group are members of the USQCD collaboration a national infrastructure for LQCD hardware and software. Our research is supported by the US Department of Energy and National Science Foundation. Software development is funded by a grant fron the Department of Energy SciDAC program and by an Aurora Early Science for Data and Learning award.