29,799 research outputs found
2d Model Field Theories at Finite Temperature and Density
In certain 1+1 dimensional field theoretic toy models, one can go all the way
from microscopic quarks via the hadron spectrum to the properties of hot and
dense baryonic matter in an essentially analytic way. This "miracle" is
illustrated through case studies of two popular large N models, the Gross-Neveu
and the 't Hooft model - caricatures of the Nambu-Jona-Lasinio model and real
QCD, respectively. The main emphasis will be on aspects related to spontaneous
symmetry breaking (discrete or continuous chiral symmetry, translational
invariance) and confinement.Comment: 90 pages, 27 figures, Contribution to the Festschrift in honor of
Boris Ioffe, edited by M. Shifma
A dual 2D model for the Quantum Hall Fluid
We present a dual two dimensional model for the Quantum Hall Fluid depending
on two parameters and show that this model has topologically non-trivial vacua
which are infrared stable fixed points of the Renormalization Group. The model
has a discrete (modular) symmetry which reproduces the fenomenological law of
corresponding states and allows for an unified description of the critical
points corresponding to Hall plateaus in terms of a 2 dimensional Conformal
Field Theory.Comment: 10 pages, Revtex, no figure
MULTI-SPECIES MULTI-PHYSICS MODELING AND VALIDATION OF HYDRODYNAMIC ELECTROCHEMICAL SYSTEM FOR USED NUCLEAR FUEL
Department of Nuclear EngineeringAccurate predictions of processes in hydrodynamic electrochemical systems require an understanding of both the surface electrochemical reactions and the bulk mass transport. Complete coupling of electrochemistry and fluid mechanics is computationally very rich for multidimensional modeling since it involves multiple components across multi-phases at the same time. Therefore, this study develops a computational model that combines a 3D model for calculating single-species mass transport and a 2D model for calculating multi-species electrochemical reactions. The computational model is validated against lab-scale experimental data using a rotating cylinder solid metal cathode and liquid metal anode in the Argonne National Laboratory. The 3D model assumes that U, the representative component in the system, dominates the hydrodynamic behavior, and thus calculates mass transport caused by the rotating solid cylinder electrode. The 2D model still reflects the diffusion of U, Pu, and Nd within a diffusion boundary layer and the bulk concentration changes of these components. The 3D model provides a diffusion layer thickness reflecting convective mass transfer effects to the 2D model. The results of the proposed model show good agreement with the reference experiment, and the model can be considered an important tool for investigating the multidimensional distributions of hydrodynamic and electrochemical variables.clos
Experimentally based numerical models and numerical simulation with parameter identification of human lumbar FSUs in traction
Numerical simulation of the behaviour of human lumbar spine segments, moreover, parameter-identification of the component organs of human lumbar FSUs are presented in
traction therapies, by using FEM analysis. First, a simple 2D model, than a refined 2D model, and finally a refined 3D model were applied for modeling lumbar FSUs. For global numerical simulation of traction therapies the material constants of component organs have been obtained from the international literature. For local parameter identification
of the component organs, an interval of the possible material moduli has been considered for each organ, and the possible combinations of real moduli were obtained,
controlling the process by the measured global deformations. In this way, the efficiency of conservative traction therapies can be improved by offering new experimental tensile material parameters for the international spine research
Vortex Structures in Model p-Wave Superconducting Sr2RuO4 -- Single 2-Dimensional Band v.s. Quasi-1-Dimensional Band
There have been an interesting debate on the primary source of chiral p-wave
superconductivity in Sr2RuO4. We present a comparative study on the vortex
structure between a single 2-dimensional (2D) band and quasi-1D band model by
using Bogoliubov-de Gennes theory. The pattern of the iso-values of the local
density of state around a vortex has a diamond shape in the quasi-1D model and
is much more isotropic in the 2D model. The spin lattice relaxation rate well
below the superconducting transition temperature is greatly enhanced in the
vortex state in the 2D model but not in the quasi-1D model. These features can
be tested by using scanning tunneling microscope and NMR to distinguish the
models for the superconductivity in Sr2RuO4.Comment: 7 pages, 6 fig
Uncertainties in the Production of p Nuclides in SN Ia Determined by Monte Carlo Variations
© Springer Nature Switzerland AG 2019Several thousand tracers from a 2D model of a thermonuclear supernova were used in a Monte Carlo post-processing approach to determine p-nuclide abundance uncertainties originating from nuclear physics uncertainties in the reaction rates.Final Accepted Versio
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