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Recently, Attaccalite et al. proposed a new expression for the exchange-correlation energy of the two-dimensional electron gas, based on quantum Monte Carlo calculations. We compare this functional with the established expression given by Tanatar and Ceperley for use in density functional calculations. As model systems serve a circular few-electron quantum dot and a square lattice of dots. For sin
The rotational behavior of T=0 and T=1 bands in the odd-odd N=Z nucleus 62Ga is studied theoretically using the spherical shell model (laboratory frame) and the cranked Nilsson-Strutinsky model (intrinsic frame). Both models give a good description of available experimental data. The role of isoscalar and isovector pairing in the T=0 and T=1 bands as functions of angular momentum is studied in the
OBJECTIVES: To explore and compare the prevalences of a wide range of comorbidities in axial spondyloarthritis (axSpA) versus the general population, and in non-radiographic versus radiographic axSpA (nr-axSpA/r-axSpA).METHOD: Well-characterized axSpA patients (n = 246) from the SPARTAKUS cohort (55% men; mean age/disease duration 52/26 years; nr-axSpA/r-axSpA = 82/164) were included, and matched
Rotational behavior inducing triaxiality is discussed for 48Cr in the cranked Nilsson-Strutinsky (CNS) model, as well as in the spherical shell model. It is shown that the low-spin region up to about 1 = 8, has a prolate well-deformed shape. At higher spins the shape is triaxial with a 'negative-γ' deformation, that is, with rotation around the classically forbidden intermediate axis. By comparing
The tunneling process that governs the decay from superdeformed to normal-deformed nuclear states is shown to be enhanced by several orders of magnitude (104 – 106) if the normal-deformed states are chaotic at the moment of decay out. The onset of (long-range) chaos may imply that the tunneling enhancement increases with decreasing angular momentum. Experimental signatures are discussed.
A detailed theoretical investigation of polarization effects in superdeformed nuclei is performed. In the pure harmonic oscillator potential it is shown that when one particle (or hole) with the mass single-particle quadrupole moment qν is added to a superdeformed core, the change of the electric quadrupole moment can be parameterized as qeff = e(bqν + a), and analytical expressions are derived fo
It is shown that the decay out from superdeformed bands is enhanced by several orders of magnitude due to the onset of chaos in normal deformed states. The onset of chaos is caused by the residual two-body interaction, that plays a crucial role for the normal deformed states at excitation energies where the decay out occurs (3-5 MeV). At these excitation energies the distribution of nearest neighb
The mechanism of band termination is discussed from the spherical shell model point of view, and the role of breaking nucleon pairs within a given j-shell configuration is stressed. Two main types of band terminations are discussed. In one type the band termination includes a sequence of states within an approximative seniority coupling scheme and therefore is smooth. In the other type the termina
Deformation properties of weakly bound nuclei are discussed in the deformed single-particle model. It is demonstrated that in the limit of a very small binding energy the valence particles in specific orbitals, characterized by a very small projection of single-particle angular momentum onto the symmetry axis of a nucleus, can give rise to the halo structure which is completely decoupled from the
Various theoretical approaches to proton emission from spherical nuclei are investigated, and it is found that all the methods employed give very similar results. The calculated decay widths are found to be qualitatively insensitive to the parameters of the proton-nucleus potential, i.e., changing the potential parameters over a fairly large range typically changes the decay width by no more than
BACKGROUND: Extensive head and neck reconstructive surgery is a complex procedure often performed in patients with multiple comorbidities, and the risk of complications is high. Evidence-based preoperative assessment and reliable risk prediction are therefore essential, and the anesthesiologist plays an important role in this process. The aim of this study was to evaluate the predictive properties
Kraft black liquor, a side-stream of the pulp and paper industry, contains lignin, hemicelluloses, and cooking chemicals. This stream is typically evaporated and burned in the recovery boiler to generate power and recover the cooking chemicals used in the pulping process to digest the wood. However, the recovery boiler is often the bottleneck of the chemical-recovery process. By removing lignin fr
The possibility that shell structure related to double-spherical shapes may produce new regions of superdeformed or "hyperdeformed" nuclei is discussed. Of special interest is the mass region around 180Hg (90Zr+90Zr) which is studied in detail. Extended cranked Nilsson-Strutinsky calculations are performed with the Woods-Saxon potential and finite-range liquid-drop model, and "hyperdeformations" w
The nearest neighbour level spacing distribution and the Δ3 statistic of level fluctuations associated with very high spin states (I ≳ 30) in rare-earth deformed nuclei are analysed by means of a cranked shell model. The many particle-many hole configurations created in the rotating Nilsson potential are mixed by the surface-delta two-body residual interaction. The levels in the near-yrast region
The dynamics of a classical, heavy system coupled to a quantum mechanical light system is studied in a simple time-dependent random matrix model, where the degree of complexity can be changed by a “chaoticity parameter.” It is shown that the energy of the quantum mechanical system diffuses as it interacts with the classical system, providing it is chaotic, while a ballistic behavior appears in the
Magnetic dipole transition matrix elements are calculated in the particle(s)+rotor model for rotational bands in superdeformed nuclei in the A = 190 region. Several bands are found to have large B(M1) values. Drastically different M1-properties appear for the maximal (K> = K1 + K2) and minimal (K< = K1 - K2) K values in strongly coupled tow-quasiparticle states. The B(M1) values may give informati
A simple model, based on random matrix theory, is utilized for the description of energy levels and level dynamics in mixed regular and chaotic quantum systems. We find that different types of level statistics, such as nearest neighbor distributions, long-range correlations, wave function analysis, curvature distributions, etc., show dramatically different sensitivity to the "chaoticity parameter.
The giant dipole resonance is studied in nuclei with exotic shapes utilizing the Woods-Saxon potential for the single-particle states, and the RPA formalism for the phonon states. Requirements on translational invariance is used to determine the residual interaction including coupling constants. The low-lying resonance component in superdeformed nuclei, which corresponds to vibrations along the lo
Extreme nuclear shapes are considered from the clustering point of view. General aspects of light nuclei which possess very exotic, elongated shapes ("α-strings") are given. The relation between superdeformation and di-molecules is considered, and it is shown that nuclear di-molecules have the same magic numbers and orbits filled as the ellipsoidal superdeformations for light nuclei, while for hea
The structure of superdeformed (SD) nuclei is discussed, and some open questions are raised. Octupole vibrations built on SD and hyperdeformed (HD) shapes are described in an analytically solvable model, and structure effects on low-lying vibrational states, as well as the deformation splitting of the giant resonance states are discussed. From cranked Nilsson-Strutinsky calculations it is predicte
