Our research addresses the key questions that comprise the Nation's nuclear physics agenda. We place heavy emphasis on the prediction of phenomena accessible at Argonne's ATLAS facility, at JLab, and at other laboratories; and on anticipating and planning for a Future Rare Isotope Beam facility (FRIB).

In theoretical and computational nuclear astrophysics we address such issues as the origin of the heaviest elements through the actinide region and the basic mechanisms of supernova explosions, and aim to identify critical nuclear parameters and systematic properties to be explored with a FRIB.

We employ quantum chromodynamics to explore hadron properties: in vacuum, as relevant to programs such as those pursued at JLab; and in-medium, as appropriate to the early universe, compact astrophysical objects, and the RHIC program. The analysis of lattice-QCD methods and results, and the prediction of observables is an integral part of this effort.

Dynamical coupled-channel models are developed to investigate the structure of nucleon resonances by using the Worldíăs data on meson production reactions induced by pions, photons and electrons, to investigate the quark-gluon reaction mechanisms to be explored with JLabíăs 12 GeV upgrade, and also to predict the neutrino-nucleus cross-sections necessary for analyzing data from experiments measuring neutrino properties.

The structure of atomic nuclei is explored in ab-initio many-body calculations based on the realistic two- and three-nucleon potentials we have constructed. These potentials give excellent fits to nucleon-nucleon elastic scattering data and the properties of light nuclei. We use quantum Monte-Carlo methods to compute nucleon-nucleus scattering phase shifts, nucleon momentum distributions, nuclear radii, transition amplitudes, and a variety of electroweak reactions important to astrophysics. Close collaboration with computer scientists enables our programs to use DOE's leadership-class computers.

Our nuclear structure and reaction program includes: coupled-channels calculations of heavy-ion reactions near the Coulomb barrier; studies of breakup reactions involving nuclei far from stability; the determination of radiative capture rates from Coulomb dissociation experiments; studies of the effects of n-p pairing on nuclei near the proton drip-line and of the heaviest elements - in both cases using many-body wavefunctions. Our programs provide much of the scientific basis for the drive to physics with rare isotopes.

Additional research in the Group focuses on: atomic and neutron physics; fundamental quantum mechanics; quantum computing; and tests of fundamental symmetries and theories unifying all the forces of nature, and the search for a spatial or temporal variation in Nature's basic parameters.

The pioneering development and use of massively parallel numerical simulations using hardware at Argonne and elsewhere is a major component of the Group's research.