25,087 research outputs found
Noncommutative Field Theory: Nonrelativistic Fermionic Field Coupled to the Chern-Simons Field in 2+1 Dimensions
We study a noncommutative nonrelativistic fermionic field theory in 2+1
dimensions coupled to the Chern-Simons field. We perform a perturbative
analysis of model and show that up to one loop the ultraviolet divergences are
canceled and the infrared divergences are eliminated by the noncommutative
Pauli term.Comment: Some references adde
Plastic Deformation of 2D Crumpled Wires
When a single long piece of elastic wire is injected trough channels into a
confining two-dimensional cavity, a complex structure of hierarchical loops is
formed. In the limit of maximum packing density, these structures are described
by several scaling laws. In this paper it is investigated this packing process
but using plastic wires which give origin to completely irreversible structures
of different morphology. In particular, it is studied experimentally the
plastic deformation from circular to oblate configurations of crumpled wires,
obtained by the application of an axial strain. Among other things, it is shown
that in spite of plasticity, irreversibility, and very large deformations,
scaling is still observed.Comment: 5 pages, 6 figure
Influência do preço externo no preço interno de frango.
bitstream/item/58658/1/CUsersPiazzonDocuments188.pd
Approaching the ground states of the random maximum two-satisfiability problem by a greedy single-spin flipping process
In this brief report we explore the energy landscapes of two spin glass
models using a greedy single-spin flipping process, {\tt Gmax}. The
ground-state energy density of the random maximum two-satisfiability problem is
efficiently approached by {\tt Gmax}. The achieved energy density
decreases with the evolution time as
with a small prefactor and a scaling coefficient , indicating an
energy landscape with deep and rugged funnel-shape regions. For the
Viana-Bray spin glass model, however, the greedy single-spin dynamics quickly
gets trapped to a local minimal region of the energy landscape.Comment: 5 pages with 4 figures included. Accepted for publication in Physical
Review E as a brief repor
Complete Fusion Enhancement and Suppression of Weakly Bound Nuclei at Near Barrier Energies
We consider the influence of breakup channels on the complete fusion of
weakly bound systems in terms of dynamic polarization potentials. It is argued
that the enhancement of the cross section at sub-barrier energies may be
consistent with recent experimental observations that nucleon transfer, often
leading to breakup, is dominant compared to direct breakup. The main trends of
the experimental complete fusion cross section for Li + Bi are
analyzed in the framework of the DPP approach.Comment: 12 pages, 2 figure
Theory of magnetic deflagration
Theory of magnetic deflagration (avalanches) in crystals of molecular magnets
has been developed. The phenomenon resembles the burning of a chemical
substance, with the Zeeman energy playing the role of the chemical energy.
Non-destructive reversible character of magnetic deflagration, as well as the
possibility to continuously tune the flammability of the crystal by changing
the magnetic field, makes molecular magnets an attractive toy system for a
detailed study of the burning process. Besides simplicity, new features, as
compared to the chemical burning, include possibility of quantum decay of
metastable spin states and strong temperature dependence of the heat capacity
and thermal conductivity. We obtain analytical and numerical solutions for
criteria of the ignition of magnetic deflagration, and compute the ignition
rate and the speed of the developed deflagration front.Comment: 17 Pages, 17 Figure caption
Structural properties of crumpled cream layers
The cream layer is a complex heterogeneous material of biological origin
which forms spontaneously at the air-milk interface. Here, it is studied the
crumpling of a single cream layer packing under its own weight at room
temperature in three-dimensional space. The structure obtained in these
circumstances has low volume fraction and anomalous fractal dimensions. Direct
means and noninvasive NMR imaging technique are used to investigate the
internal and external structure of these systems.Comment: 9 pages, 4 figures, accepted in J. Phys. D: Appl. Phy
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