77,981 research outputs found
Nuclear Physics from Lattice QCD
We review recent progress toward establishing lattice Quantum Chromodynamics
as a predictive calculational framework for nuclear physics. A survey of the
current techniques that are used to extract low-energy hadronic scattering
amplitudes and interactions is followed by a review of recent two-body and
few-body calculations by the NPLQCD collaboration and others. An outline of the
nuclear physics that is expected to be accomplished with Lattice QCD in the
next decade, along with estimates of the required computational resources, is
presented.Comment: 56 pages, 39 pdf figures. Final published versio
Chiral dynamics of the nuclear equation of state
We present a new chiral power expansion scheme for the nuclear equation of
state. The scheme is effective in the sense that it is constructed to work
around nuclear saturation density. The leading and subleading terms are
evaluated and are shown to provide an excellent equation of state. As a further
application we considered the chiral quark condensate in nuclear matter.
Already at nuclear saturation density we predict a substantially smaller
reduction of the condensate as compared to conventional approaches.Comment: 7 pages, 4 figures, talk given at: "QCD at Finite Baryon Density",
Bielefeld (April 1998
Radial vibrations of BPS skyrmions
We study radial vibrations of spherically symmetric skyrmions in the BPS
Skyrme model. Concretely, we numerically solve the linearised field equations
for small fluctuations in a skyrmion background, both for linearly stable
oscillations and for (unstable) resonances. This is complemented by numerical
solutions of the full nonlinear system, which confirm all the results of the
linear analysis. In all cases, the resulting fundamental excitation provides a
rather accurate value for the Roper resonance, supporting the hypothesis that
the BPS Skyrme model already gives a reasonable approximate description of this
resonance. Further, for many potentials additional higher resonances appear,
again in agreement with known experimental results.Comment: Latex, 41 pages, 22 pdf figures; v2: minor change
Shell-model calculations and realistic effective interactions
A review is presented of the development and current status of nuclear
shell-model calculations in which the two-body effective interaction is derived
from the free nucleon-nucleon potential. The significant progress made in this
field within the last decade is emphasized, in particular as regards the
so-called V-low-k approach to the renormalization of the bare nucleon-nucleon
interaction. In the last part of the review we first give a survey of realistic
shell-model calculations from early to present days. Then, we report recent
results for neutron-rich nuclei near doubly magic 132Sn and for the whole
even-mass N=82 isotonic chain. These illustrate how shell-model effective
interactions derived from modern nucleon-nucleon potentials are able to provide
an accurate description of nuclear structure properties.Comment: 71 pages, to be published in Progress in Particle and Nuclear Physic
Techniques in Analytic Lamb Shift Calculations
Quantum electrodynamics has been the first theory to emerge from the ideas of
regularization and renormalization, and the coupling of the fermions to the
virtual excitations of the electromagnetic field. Today, bound-state quantum
electrodynamics provides us with accurate theoretical predictions for the
transition energies relevant to simple atomic systems, and steady theoretical
progress relies on advances in calculational techniques, as well as numerical
algorithms. In this brief review, we discuss one particular aspect connected
with the recent progress: the evaluation of relativistic corrections to the
one-loop bound-state self-energy in a hydrogenlike ion of low nuclear charge
number, for excited non-S states, up to the order of alpha (Zalpha)^6 in units
of the electron mass. A few details of calculations formerly reported in the
literature are discussed, and results for 6F, 7F, 6G and 7G states are given.Comment: 16 pages, LaTe
Toward ab initio density functional theory for nuclei
We survey approaches to nonrelativistic density functional theory (DFT) for
nuclei using progress toward ab initio DFT for Coulomb systems as a guide. Ab
initio DFT starts with a microscopic Hamiltonian and is naturally formulated
using orbital-based functionals, which generalize the conventional
local-density-plus-gradients form. The orbitals satisfy single-particle
equations with multiplicative (local) potentials. The DFT functionals can be
developed starting from internucleon forces using wave-function based methods
or by Legendre transform via effective actions. We describe known and
unresolved issues for applying these formulations to the nuclear many-body
problem and discuss how ab initio approaches can help improve empirical energy
density functionals.Comment: 69 pages, 16 figures, many revisions based on feedback. To appear in
Progress in Particle and Nuclear Physic
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