D. W. L. Sprung

Spherical nuclei in the local density approximation

Abstract Hartree-Fock calculations have been performed for the closed-shell nuclei 4 He, 16 O, 40 Ca, 48 Ca, 90 Zr and 208 Pb, using the density-dependent effective interaction of Sprung and Banerjee. Overall good results were obtained when the force is adjusted to saturate nuclear matter with −16.5 MeV energy at k F = 1.35 fm −1 . The influence of saturation properties, compressibility and symmetry energy upon the finite-nucleus results is studied. The neutronrich isotopes of He up to A = 10 and O up to A = 30 are also considered.

Construction d'un potentiel nucléon-nucléon à cȩur très mou (ssc)

Abstract A phenomenologieal local nucleon-nucleon potential has been constructed satisfying the following criteria: a high-quality fit to two-body bound-state and scattering data up to 350 MeV; the amplitudes of all components are weak in the sense that perturbation theory in nuclear matter converges rapidly; the tensor force in the triplet even state is much weaker than in other potential models. Close agreement is found between Brueckner-theory and perturbation-theory calculations in nuclear matter. The deuteron form factor is well reproduced with PD = 5.5%.

Scattering by a finite periodic potential

The problem of scattering in one dimension by a potential which consists of N identical cells is solved in a transparent manner. The N‐cell transmission and reflection amplitudes are expressed in terms of the single‐cell amplitudes and the Bloch phase. As examples the results are applied to a row of delta‐function potentials, and to a row of square wells, and it is shown that these expressions provide an immediate understanding of the results of detailed calculations.

Super-soft-core nucleon-nucleon interaction with π-, ρ- and gw-exchange contributions

Abstract An improved version of the super-soft-core interaction is presented. The known π-, ρ- and gw-exchange contributions are incorporated, while the core and the remainder of the intermediate range are treated phenomenologically. The potential gives a high-quality fit to the two-body bound-state and scattering data up to 350 MeV. The amplitudes are weak in the sense that in nuclear matter, the ratio of second-order to first-order energy perturbations (for the scalar components) are in the region 20–30%. The wound integral κ = 0.077 at kF = 1.4 fm−1. The triplet-even tensor component is weaker than in other phenomenological potentials, but the deuteron form factor is well reproduced. The percentage D-state is 5.92%.

Binding and saturation of nuclear matter by the reference spectrum method

The properties of nuclear matter have been calculated for the Hamada-Johnston, Reid, and Bressel-Kerman potentials by the reference-spectrum method. Inclusion of three-body cluster effects according to the theory of Bethe leads to good agreement with experiment. The methods of calculation are discussed. The third-order reference spectrum correction term is derived and shown to be important for the 3S−3D state where the tensor force acts. The soft-core Bressel potential gives about 2 MeV extra binding but saturates at a higher density. The potential energy of particle states is attractive and depends quite strongly on momentum. It is found that the reference spectrum parameters should have values near Δ = 0.6 and m∗ = .98.

Nuclear sizes and the isotope shift

Darwin-Foldy nuclear-size corrections in electronic atoms and nuclear radii are discussed from the nuclear-physics perspective. The interpretation of precise isotope-shift measurements is formalism dependent, and care must be exercised in interpreting these results and those obtained from relativistic electron scattering from nuclei. We strongly advocate that the entire nuclear-charge operator be used in calculating nuclear-size corrections in atoms rather than relegating portions of it to the nonradiative recoil corrections. A preliminary examination of the intrinsic deuteron radius obtained from isotope-shift measurements suggests the presence of small meson-exchange currents (exotic binding contributions of relativistic order) in the nuclear charge operator, which contribute approximately (1) /(2) {percent}. {copyright} {ital 1997} {ital The American Physical Society}

Surface TE waves on 1D photonic crystals

Accurate analytic approximations are developed for the band gap boundaries and surface waves of a 1D photonic crystal, making use of the semiclassical theory recently developed by the authors. These analytic results provide useful insight on systematics of surface states.

Determination of the deuteron mean square radius

Abstract Three new methods are applied to the problem of extracting the deuteron rms matter radius from the experimental ratio of (e, d) to (e, p) scattering. A new value rEd = 1.953 (3) fm is obtained. The asymptotic method also yields 〈r4〉 = 54.5 ± 0.3 fm4 and 〈r6〉 = 1914 ± 20 fm6. Potential models of the deuteron are apparently unable to explain this rEd simultaneously with the low energy effective-range parameters of the neutron-proton system.

Isotope effects in tin with the local density approximation

Abstract Properties of the even isotopes of tin are calculated using the density dependent effective interaction G-0. Excellent agreement is found for the gross structure of these nuclei. The isotope shift is studied and the factors governing this effect are elucidated.

Quantum chaos in terms of Bohm trajectories

Abstract Within Bohms interpretation of quantum mechanics, the classical definition of chaos can be applied to particle trajectories. We show that a one-dimensional system is not chaotic, while a generic two-dimensional system may be, and the sum of the Lyapunov exponents for a Bohm orbit is zero. We also argue that the quantum vortex is the main factor driving chaotic motion.