No-Core Shell Model The ab-initio No-Core Shell Model (NCSM) aims for a consistent treatment of both nuclear structure and nuclear reactions with "fundamental" inter-nucleon interactions. Here, fundamental means that parameters defining the interactions are determined by the two-, three-, and four-nucleon systems, and generally are not fit to reproduce spectra in A> 4 body systems. This goal is shared with other many-body methods applied to nuclei such as the GFMC and CC approaches. The NCSM adopts a variety of fundamental two-nucleon interactions ranging from the Argonne potentials to non-local effective-field theory (EFT) potentials, which are derived to reproduce the two-nucleon phase shifts and deuteron properties. The NCSM also adopts three-nucleon interactions based on the Tucson-Melbourne and EFT potentials, constrained to reproduce properties of three- and, sometimes, four-nucleon systems. The NCSM adopts an effective interaction theory to transform the fundamental interactions into an effective interaction for a specified nucleus in a selected harmonic oscillator basis space. The effective interaction is derived for a fixed cluster size (2 or 3 nucleons at present) using the formalism of Okubo and Lee and Suzuki. Formally, however, the theory contains two-, three-, and up to A-body interactions, even if the original interaction was only, e.g., two-body in character. The effective interaction utilized in the NCSM is designed to converge to the exact result in the limits that the active model space extends to infinity and/or the cluster number in the effective interaction tends to A. Practical calculations in the NCSM require a compromise between these two limits and a careful study of convergence. NCSM calculations are limited by the size of the active basis space, and by the cluster size in the effective interaction. The calculations are performed in the harmonic oscillator basis using either Jacobi coordinates or single-particle coordinates, the latter being more efficient for A>4 nuclei. The Jacobi coordinate approach is necessary for exact solutions of A < 5 nuclei as well as for the derivation of the effective Hamiltonians. The active basis space is defined by the total number of oscillator quanta, Nmax. This enables one to exactly separate the intrinsic degrees of freedom from spurious center-of-mass excitations in the case of the single-particle coordinates. As Nmax increases (in even increments), the overall dimension increases by approximately an order of magnitude, and the matrix diagonalization scales approximately as N^1.3-N^1.5, where N is the basis dimension. In addition, current experience indicates that, when increasing from two-nucleon to three-nucleon clusters in the effective interaction the computational effort grows by nearly two orders of magnitude and, the memory requirements also increase dramatically. For example, p-shell calculations with Nmax=6 require 750,000,000 real numbers to define just the three-body Hamiltonian in the m-scheme, and the basis dimensions exceed 43,000,000 for nuclei from 12C to 16O. Calculations for these nuclei have been performed on THUNDER with EFT NN and NNN interactions at LLNL using 3486 processors (out of a the total 4096) and 2GB/processor to store the entire Hamiltonian matrix in memory across the computer. The lowest 15 eigenvalues and eigenfunctions as well as a set of observables are obtained in 2-5 hours following 500 Lanczos iterations. Extensions to describe nuclear reactions are in development. Early applications have been based on evaluating the radial-cluster form factor, namely the measure of how much the composite nucleus is represented by two clusters as a function of their separation. It has been recognized that the asymptoitic behavior of the cluster form factor is dominated in the NCSM by the harmonic oscillator basis and this has been corrected to give behaviors appropriate for the binding energy of the cluster. Applications to radiative capture have been carried out and excellent results have been obtained for 7Be(p,gamma)8B. This formalism is now being extended in the spirit of the resonating group method to project the Hamiltonian onto the requisite active model spaces for the two clusters, and an integral-differential equation for the relative wave function is derived and solved. This procedure should lead to a fundamental theory for reactions in light nuclei relevant to nuclear astrophysics and NNSA appications. Examples of great interest are 7Be(p,gamma)8B, 3He(alpha,gamma)7Be, 6Li(n,alpha)t, 10Be(n,gamma)11Be, triple-alpha fusion to form 12C, and 12C(alpha,gamma)16O. Recent successes: 1) Benchmark calculations comparing 4He observables with GFMC and 5 other methods agree to 0.3% for the Argonne v8' potential. 2) Large basis calculations with NN interactions with basis dimensions exceeding 1 Billion. 3) Demonstration of value for testing fundamental symmetries with the 10C to 10B super-allowed Fermi transition 4) Development of methods for evaluating effective operators for experimental observables and successful application of the renormalization procedure to inclusive (e,e') longitudinal nuclear response in 4He and 12C. 5) Inclusion of three-body clusters in the effective interaction and a demonstrated improvement in the convergence with NN interactions. 6) Inclusion of three-nucleon interaction (Tucson-Melbourne) which improves the level ordering in 10B (the only parameter in the NNN force is fixed by the triton binding energy). Demonstrates the three-nucleon interaction strongly affects level structure and transition amplitudes, especially Gamow-Teller. Three nucleon interactions are shown to be very important for exclusive neutrino cross sections on 12C. 7) Inclusion of EFT-based three-nucleon interaction (N2LO) with calculations up to Nmax=6 for p-shell nuclei. The two EFT parameters were fixed by the A=3 and 4 binding energies and 4He radius. Level ordering and binding energies for p-shell nuclei are improved. 8) Development of formalism for evaluation of cluster form factors and spectroscopic factors. Calculation of proton and neutron radiative capture. Good agreement with recent direct measurement data for 7Be(p,gamma)8B. 9) Succesful benchmark calculations between the NCSM and the Lorentz-Integral transform method to describe the total photodisintigration of 4He. Physics goals for the next five years: 1) Comprehensive study of the EFT three-nucleon interaction for p-shell nuclei. Study convergence properties for oscillator parameter and uncertainties caused by NN EFT parameters. 2) Develop the formalism to utilize four-body clusters in the effective interaction and study effects, such as alpha clustering. 3) Utlize N3LO EFT interactions including four-body term. The number of parameters is the same as at N2LO. 4) Develop an improved solution to the "effective operator problem". This may require a different formulation that will be much more computationally intensive. 5) Develop an effective operator approach with a core for extensions to heavier nuclei. 6) Develop RGM-like approach to nuclear reactions and solve integral- differential coupled-channels equations to obtain cross sections. 7) Perform benchmark comparisons in p-shell nuclei with GFMC and CC efforts for nuclear structure results using two-nucleon and using two-nucleon plus three-nucleon interactions as well as for nuclear reaction results. Computational and Computer Science needs: 1) Develop capabilities for Nmax = 8 p-shell calculations with NNN interactions. NCSM calculations with NNN interactions at Nmax=6 are currently at the limit of what can be accomplished on THUNDER as it generally requires dedicated runs utilizing the full machine. Optimization for the two codes currently used is needed. For 12C to 16O, the full many-body matrix requires approximately 6TB to store. In order to eliminate I/O MFD stores the full matrix in RAM and requires enough processors to fit the matrix. Optimization of the matrix multiplication on each node, and broadcasting results is needed. An examination of whether coding inner loops in machine language will improve efficieny is planned. The other code, REDSTICK, computes the application of the Hamiltonian on the fly and can run on an arbitrary number of processors. It needs approximately 2.4GB to store the Hamiltonian operators and requisite information. On the same number of processors, MFD currently runs approximately 40 times faster than REDSTICK for Nmax=6. It is estimated that factor of 4-8 improvement can be attained in REDSTICK. Load balance efficiency needs to be examined further. 2) Efficient parallelization of the computer programs to calculate the effective interactions and extend the dimension of the three-body spaces. Currently, these codes do not fully utilize parallel processing. For example an Nmax=6 three-nucleon interaction takes approximately 6 days to compute on a single processor. Improvement of the efficiency of the code that transforms the three-body effective interaction from Jacobi coordinate basis to single particle basis to perform the Nmax =8 calculation. 3) Develop an "universal" and parallel transition-density code. Needed to compute transition densities with wave functions obtained from various codes currently used. 4) Develop parallelized computer codes to solve the non-local RGM-like integral-differential coupled-channels equations. Seamless interface of the structure wave functions into reaction formalism.