119880793
Optimized perturbation theory in the Gross-Neveu model
117188910
The renormalization‐scheme‐dependence problem and its solution
I explain, in ‘‘uncompromising’’ terms, the solution to the renormalization‐scheme‐dependence problem.
122752251
Comment on ''An alternative implementation of the 'principle of minimal sensitivity'''
I explain that the difficulties encountered by Wrigley in the preceding paper arise only because he is attempting to find the stationary value of an undefined function.
123093258
QCD and final-state jet measures in leptoproduction
Abstract Various infrared-safe measures of jet-like-ness in leptoproduction are studied in QCD perturbation theory using a general formalism. This quantifies the effects predicted in a previous paper. The nucleon remnants jet is found to be distinctly narrower than the quark jet.
120598082
The Gaussian Effective Potential. 1. Quantum Mechanics
119407227
Optimization and the Ultimate Convergence of QCD Perturbation Theory
Abstract I suggest that QCD perturbation theory can be convergent, and that “optimization” of the renormalization scheme choice is essential in achieving this. Arguing that higher orders probe shorter distances, I suggest that the effective expansion parameter (the “optimized” couplant) decreases at high orders, leading to an induced convergence. The mechanism is illustrated by a simple mathematical example. The point is that, even if the perturbation series is divergent in all fixed renormalization schemes, the sequence of “optimized” approximations may still converge. It is emphasized that the limit approached by perturbation theory, if any, will not be the exact result of the full theory. Allegations that QCD series are not Borel-summable are critically re-examined in this light.
31581119
The TDHF code Sky3D
The nuclear mean-field model based on Skyrme forces or related density functionals has found widespread application to the description of nuclear ground states, collective vibrational excitations, and heavy-ion collisions. The code Sky3D solves the static or dynamic equations on a three-dimensional Cartesian mesh with isolated or periodic boundary conditions and no further symmetry assumptions. Pairing can be included in the BCS approximation for the static case. The code is implemented with a view to allow easy modifications for including additional physics or special analysis of the results.
14658401
Dipole giant resonances in deformed heavy nuclei
The spectral distribution of isovector dipole strength is computed using the time-dependent Skyrme-Hartree-Fock method with subsequent spectral analysis. The calculations are done without any imposed symmetry restriction, allowing any nuclear shape to be dealt with. The scheme is used to study the deformation dependence of giant resonances and its interplay with Landau fragmentation (owing to 1ph states). Results are shown for the chain of Nd isotopes, superdeformed {sup 152}Dy, triaxial {sup 188}Os, and {sup 238}U.
118393197
Single-particle dissipation in TDHF studied from a phase-space perspective
N. Loebl, A. S. Umar, J.A. Maruhn, P.-G. Reinhard, P.D. Stevenson, and V. E., Oberacker Institut fuer Theoretische Physik, Universitaet Frankfurt, D-60438 Frankfurt, Germany Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, USA Institut fuer Theoretische Physik II, Universitaet Erlangen-Nuernberg, D-91058 Erlangen, Germany and Department of Physics, University of Surrey, Guildford, GU2 7XH, UK (Dated: August 30, 2012)
120382191
Densities of superheavy nuclei at closed shells
We employed the Skynne-Hartree-Fock + BCS model to investigate the density distributions of even-even superheavy nuclei around the predicted rnagic numbers of Z = 114, 120, 126 and N = 172, 184. The central depressions in densities are shown in the heaviest nuclei with Z <= 120 and N <= 178, which is due to high-j orbits occupied. However, densities become flatter when deformations occur. The superheavy nuclei with N = 180-188 and Z = 126 have no central depressions, due to that low-j orbits become occupied. Shell closures in the superheavy mass region are isospin dependent.
16803754
Self-consistent description of dysprosium isotopes in the doubly midshell region
Dy in the framework of density-dependent Hartree-Fockcalculations with BCS pairing correlations. Further deformed Hartree-Fock with angular-momentum projectionand band-mixing calculations explore the yrast spectra of the nuclides approaching the neutron midshell.Predictions of high-K states in the doubly midshell nucleus