3,531 research outputs found
Orbit based procedure for doublets of scalar fields and the emergence of triple kinks and other defects
In this work we offer an approach to enlarge the number of exactly solvable
models with two real scalar fields in (1+1)D. We build some new two-field
models, and obtain their exact orbits and exact or numerical field
configurations. It is noteworthy that a model presenting triple-kinks and
double-flat-top lumps is among those new models
Analytical Multi-kinks in smooth potentials
In this work we present an approach which can be systematically used to
construct nonlinear systems possessing analytical multi-kink profile
configurations. In contrast with previous approaches to the problem, we are
able to do it by using field potentials which are considerably smoother than
the ones of Doubly Quadratic family of potentials. This is done without losing
the capacity of writing exact analytical solutions. The resulting field
configurations can be applied to the study of problems from condensed matter to
brane world scenarios
Asymmetrical bloch branes and the hierarchy problem
We investigate a two scalar fields split braneworld model which leads to a
possible approach to the hierarchy problem within the thick brane scenario. The
model exhibits a resulting asymmetric warp factor suitable for this purpose.
The solution is obtained by means of the orbit equation approach for a specific
value of one of the parameters. Besides, we analyze the model qualitative
behaviour for arbitrary parameters by inspecting the underlying dynamical
system defined by the equations which give rise to the braneworld model. We
finalize commenting on the metric fluctuation and stability issues.Comment: 8 pages, 7 figure
Ukraine should double down on reform in 2018. Why tough love from international partners and pressure from Ukrainian society is necessary. EPC Commentary, 17 January 2018
Ukraine has come a long way since the Revolution of Dignity (Maidan) in 2013-14. The country is going through a long-term transformation under difficult circumstances, fighting a war on two fronts. First, the conflict in Eastern Ukraine, and second the fight against those both inside and outside government that strongly resist change, not least the deeply embedded oligarchic interests in the country. Significant pressure needs to come from both Ukrainian society and Ukraine’s international partners to sustain the reform momentum
Qualidade do leite armazenado em tanques coletivos.
Importância da refrigeração do leite ; Tanques coletivos; Pesquisa sobre a qualidade do leite de tanques coletivos; Uma segunda pesquisa: maio de 2007 a junho de 2008.bitstream/item/65295/1/CT-99-Qualid-leite-armaz-tanq-coletivos.pd
Determinação da relação solo planta em pomar de citros com diferentes combinações copa/porta-enxerto.
A importância socioeconômica da citricultura no Nordeste brasileiro é incontestável. No entanto, problemas como a distribuição irregular de chuva na região onde se localizam os pomares - concentrada em seis a oito meses do ano - interferem de forma direta no crescimento e desenvolvimento das plantas. Em função disso, a busca de genótipos tolerantes a deficiência hÃdrica é crucial para a permanência da citricultura nesse território
Spin-polarized current and shot noise in the presence of spin flip in a quantum dot via nonequilibrium Green's functions
Using non-equilibrium Green functions we calculate the spin-polarized current
and shot noise in a ferromagnet--quantum-dot--ferromagnet (FM-QD-FM) system.
Both parallel (P) and antiparallel (AP) magnetic configurations are considered.
Coulomb interaction and coherent spin-flip (similar to a transverse magnetic
field) are taken into account within the dot. We find that the interplay
between Coulomb interaction and spin accumulation in the dot can result in a
bias-dependent current polarization . In particular, can be
suppressed in the P alignment and enhanced in the AP case depending on the bias
voltage. The coherent spin-flip can also result in a switch of the current
polarization from the emitter to the collector lead. Interestingly, for a
particular set of parameters it is possible to have a polarized current in the
collector and an unpolarized current in the emitter lead. We also found a
suppression of the Fano factor to values well below 0.5.Comment: Published version. 13 pages, 7 figure
- …