Effects of nuclear structure in the transport coefficients of large-scale collective motion

2004 ◽  
Author(s):  
F. Ivanyuk
Keyword(s):  
Nuclear Structure ◽  
Large Scale ◽  
Collective Motion ◽  
Transport Coefficients

THE TRANSPORT COEFFICIENTS OF LARGE SCALE NUCLEAR COLLECTIVE MOTION

2008 ◽  
Vol 17 (01) ◽  
pp. 60-71
Author(s):  
FEDIR IVANYUK
Keyword(s):  
Large Scale ◽  
Collective Motion ◽  
Transport Coefficients ◽  
Harmonic Approximation ◽  
Linear Response Theory ◽  
Many Body ◽  
Collective Variables ◽  
Angular Rotation ◽  
Shell Effects ◽  
Deformation Parameters

An approach to the description of slow collective motion at finite excitations based on the linear response theory and locally harmonic approximation is discussed. The method relies on the assumption that the nuclear many-body Hamiltonian can be approximated by a one-body Hamiltonian which in parametric way depends on the collective variables (deformation parameters) and allows for the account of the shell effects, pairing correlation, angular rotation. Special attention is paid to the removal of spurious contributions caused by the violation of the conservation laws. As an application of the theory, the microscopic transport coefficient are used for the description of reaction 18O + 208 Pb within the Langevin approach.

scholarly journals Realistic Calculations for Cold Dark Matter Detection Rates

2020 ◽  
Vol 13 ◽  
pp. 283
Author(s):  
T. S. Kosmas ◽  
M. Kortelainen ◽  
J. Suhonen ◽  
J. Toivanen
Keyword(s):  
Dark Matter ◽  
Nuclear Structure ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Scattering Problem ◽  
Realistic Model ◽  
Supersymmetric Particle ◽  
Detection Rates ◽  
Model Spaces ◽  
Event Rates

The scattering of the cold dark matter (CDM) candidate LSP (Lightest Supersymmetric Particle) off nuclei is investigated. We focus on the nuclear-structure aspects of the LSP-nucleus scattering problem and computed the associated event rates as well as the annual modulation signals for the 23Na, 71Ga, 73Ge and 127I CDM detectors by using the nuclear shell model in realistic model spaces and exploiting microscopic effective two-body interactions. Large-scale computations had to be performed in order to achieve convergence of the results. The relevance of the spin-dependent and coherent channels for the event rates is discussed, from both the nuclear structure and the SUSY-model viewpoints.

scholarly journals Fermi bubbles from stochastic acceleration of electrons in a Galactic outflow

2019 ◽  
Vol 622 ◽  
pp. A203 ◽  
Author(s):  
P. Mertsch ◽  
V. Petrosian
Keyword(s):  
Large Scale ◽  
Transport Coefficients ◽  
Strong Shock ◽  
High Energy ◽  
Brightness Distribution ◽  
Shock Acceleration ◽  
Galactic Centre ◽  
Large Reservoir ◽  
Stochastic Acceleration ◽  
Multi Wavelength

The discovery of the Fermi bubbles – a huge bilobular structure seen in GeV gamma-rays above and below the Galactic centre – implies the presence of a large reservoir of high energy particles at ~10 kpc from the disk. The absence of evidence for a strong shock coinciding with the edge of the bubbles, and constraints from multi-wavelength observations point towards stochastic acceleration by turbulence as a likely mechanism of acceleration. We have investigated the time-dependent acceleration of electrons in a large-scale outflow from the Galactic centre. For the first time, we present a detailed numerical solution of the particle kinetic equation that includes the acceleration, transport and relevant energy loss processes. We also take into account the addition of shock acceleration of electrons at the bubble’s blast wave. Fitting to the observed spectrum and surface brightness distribution of the bubbles allows determining the transport coefficients, thereby shedding light on the origin of the Fermi bubbles.

scholarly journals A first-principle mechanism for particulate aggregation and self-assembly in stratified fluids

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Roberto Camassa ◽  
Daniel M. Harris ◽  
Robert Hunt ◽  
Zeliha Kilic ◽  
Richard M. McLaughlin
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
Collective Motion ◽  
Solute Diffusion ◽  
Many Body ◽  
Complex Interplay ◽  
Fluid Systems ◽  
The Individual ◽  
Many Particles ◽  
Fundamental Mechanism

AbstractAn extremely broad and important class of phenomena in nature involves the settling and aggregation of matter under gravitation in fluid systems. Here, we observe and model mathematically an unexpected fundamental mechanism by which particles suspended within stratification may self-assemble and form large aggregates without adhesion. This phenomenon arises through a complex interplay involving solute diffusion, impermeable boundaries, and aggregate geometry, which produces toroidal flows. We show that these flows yield attractive horizontal forces between particles at the same heights. We observe that many particles demonstrate a collective motion revealing a system which appears to solve jigsaw-like puzzles on its way to organizing into a large-scale disc-like shape, with the effective force increasing as the collective disc radius grows. Control experiments isolate the individual dynamics, which are quantitatively predicted by simulations. Numerical force calculations with two spheres are used to build many-body simulations which capture observed features of self-assembly.

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