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Ab initio no‐core shell‐model solutions for the structure of light nuclei are shown to be dominated by low‐spin and high‐deformation configurations. This implies that only a small fraction of the full model space is important for a description of bound‐state properties of light nuclei. It further points to the fact that the coupling scheme of choice for carrying out calculations for light nuclear systems is an algebraic‐based, no‐core shell‐model scheme that builds upon an LS coupling [SO(3)⊗SU(2)] foundation with the spatial part of the model space further organized into its symplectic [SO(3)⊂SU(3)⊂Sp(3, R)] structure. Results for 12C and 16O are presented with the cluster nature of the excited 0+ states in 16O analyzed within this framework. The results of the analysis encourages the development of a no‐core shell model code that takes advantage of algebraic methods as well as modern computational techniques. Indeed, although it is often a very challenging task to cast complex algebraic constructs into ...

Understanding the origin, structure, and phases of hadronic matter is a forefront research area in physics. An integral part of this challenge is to achieve realistic modeling of the complex dynamics of atomic nuclei, which is key to comprehending the evolution of the universe from a fundamental quark/gluon level. We recently demonstrated the potential power of an innovative concept, the ab initio symplectic no‐core shell model (Sp‐NCSM), based on expanding the conventional harmonic oscillator basis in terms of the symmetry‐adapted and physically relevant symplectic basis, to reach new domains of nuclear structure. Using realistic interactions tied to Quantum Chromo‐dynamics (QCD), the Sp‐NCSM approach holds promise to build the bridge from QCD to measured properties of light nuclei, predict diverse features of unstable nuclei crucial for astrophysical processes, and provide nuclear structure information essential for cosmology and probing physics beyond the standard model.

Recent advances in ab initio quantum many-body methods and growth in computer power now enable highly precise calculations of nuclear structure. The precision has attained a level sufficient to make clear statements on the nature of 3-body forces in nuclear physics. Total binding energies, spin-dependent structure effects, and electroweak properties of light nuclei play major roles in pinpointing properties of the underlying strong interaction. Eventually, we anticipate a theory bridge with immense predictive power from QCD through nuclear forces to nuclear structure and nuclear reactions. Light front Hamiltonian quantum field theory offers an attractive pathway and we outline key elements.

Singular integral equations for meson spectra are obtained by making a Fock space expansion of the quantum chromodynamics (QCD). The expansions are truncated and approximate equations for the mass eigenvalues and eigenvectors are derived variationally using an expansion in cubic B‐splines. In these initial variational calculations we restrict ourselves to configurations having a maximum of one qq pair and twenty gluons. However these variational results compare favorably with the results of the phenomenological two‐constituent quark model and with experiment.

Finite Temperature Hartree Fock (FTHF) calculations have been performed in 4He in a quasiparticle basis which contains nucleons as well as Δ(1232) isobars. For temperatures less than 10 MeV, the isobar admixture probabilities are negligibly small.