12,102 research outputs found
Integrable nonlinear field equations and loop algebra structures
We apply the (direct and inverse) prolongation method to a couple of
nonlinear Schr{\"o}dinger equations. These are taken as a laboratory field
model for analyzing the existence of a connection between the integrability
property and loop algebras. Exploiting a realization of the Kac-Moody type of
the incomplete prolongation algebra associated with the system under
consideration, we develop a procedure with allows us to generate a new class of
integrable nonlinear field equations containing the original ones as a special
case.Comment: 13 pages, latex, no figures
Study to determine suitable high temperature, high altitude, total temperature sensors Final report
High temperature, high altitude total temperature sensor development - thermocouple devic
BEC-BCS crossover in "magnetized" Feshbach-resonantly paired superfluids
We map out the detuning-magnetization phase diagram for a ``magnetized''
(unequal number of atoms in two pairing hyperfine states) gas of fermionic
atoms interacting via an s-wave Feshbach resonance (FR). For large positive FR
detuning a normal magnetized Fermi gas is stable above an exponentially small
value of the population difference. Below this critical value the phase diagram
is dominated by coexistence of a magnetized normal gas and a singlet paired
superfluid with the latter exhibiting a BCS-Bose Einstein condensate crossover
with reduced detuning. On the BCS side of strongly overlapping Cooper pairs, a
sliver of finite-momentum paired Fulde-Ferrell-Larkin-Ovchinnikov magnetized
phase intervenes between the phase separated and normal states. In contrast,
for large negative detuning a uniform, polarized superfluid, that is a coherent
mixture of singlet Bose-Einstein-condensed molecules and fully magnetized
single-species Fermi-sea, is a stable ground state.Comment: 4 RevTeX pages, 2 figures. Minor changes from previous versio
Influence of cold-rolling reduction on retained austenite texture in cold-rolled and intercritically annealed TRIP-assisted steel
The newly developed multiphase transformation-induced plasticity (TRIP) steels are of interest for industrial applications because of their excellent combination of high strength and ductility. Their performance can be successfully controlled by designing an optimum balance in the volume fractions of ferrite, bainite and retained austenite. The characteristics of the retained austenite are considered to be the main key to achieving the desired final properties. Against this background, the effects of retained austenite characteristics, such as volume fraction, carbon concentration, size and shape, on the behaviour of TRIP steels have been studied. The crystallographic orientation of the retained austenite was measured by electron backscattered diffraction (EBSD). The effect of initial cold-rolling reduction on the microtexture development of the retained austenite was studied on an aluminium-containing TRIP steel. The results show that, by increasing the cold-rolling reduction before the final austempering, the main components of the face-centred cubic phase, i.e. copper, brass and Goss, dominate the texture of the retained austenite. In contrast, the copper and Goss components of the retained austenite are absent in the texture of lightly deformed sheets. The features of the preferred orientation of the retained austenite are discussed and explained in terms of the annealing texture of the recrystallized ferrite and bainite
Dirac Spinors and Flavor Oscillations
In the standard treatment of particle oscillations the mass eigenstates are
implicitly assumed to be scalars and, consequently, the spinorial form of
neutrino wave functions is not included in the calculations. To analyze this
additional effect, we discuss the oscillation probability formula obtained by
using the Dirac equation as evolution equation for the neutrino mass
eigenstates. The initial localization of the spinor state also implies an
interference between positive and negative energy components of mass eigenstate
wave packets which modifies the standard oscillation probability.Comment: 14 pages, 1 figure, AMS-Te
Equations of the reaction-diffusion type with a loop algebra structure
A system of equations of the reaction-diffusion type is studied in the
framework of both the direct and the inverse prolongation structure. We find
that this system allows an incomplete prolongation Lie algebra, which is used
to find the spectral problem and a whole class of nonlinear field equations
containing the original ones as a special case.Comment: 16 pages, LaTex. submitted to Inverse Problem
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