36,114 research outputs found
Nematic liquid crystal dynamics under applied electric fields
In this paper we investigate the dynamics of liquid crystal textures in a
two-dimensional nematic under applied electric fields, using numerical
simulations performed using a publicly available LIquid CRystal Algorithm
(LICRA) developed by the authors. We consider both positive and negative
dielectric anisotropies and two different possibilities for the orientation of
the electric field (parallel and perpendicular to the two-dimensional lattice).
We determine the effect of an applied electric field pulse on the evolution of
the characteristic length scale and other properties of the liquid crystal
texture network. In particular, we show that different types of defects are
produced after the electric field is switched on, depending on the orientation
of the electric field and the sign of the dielectric anisotropy.Comment: 7 pages, 12 figure
A utilização de Unidades Demonstrativas para a transferência de tecnologia.
A demonstração das tecnologias agrĂcolas Ă© uma das formas de transferĂŞncia adotadas pela Empresa Brasileira de Pesquisa Agropecuária ? Embrapa. Essa demonstração Ă© feita para aproximar o agricultor dos benefĂcios gerados pela pesquisa. Nesse contexto, se insere o conceito de Unidade Demonstrativa (UD), mas o que vem a ser uma UD?bitstream/item/29508/1/adocao.pd
Strong superadditivity and monogamy of the Renyi measure of entanglement
Employing the quantum R\'enyi -entropies as a measure of
entanglement, we numerically find the violation of the strong superadditivity
inequality for a system composed of four qubits and . This violation
gets smaller as and vanishes for when the
measure corresponds to the Entanglement of Formation (EoF). We show that the
R\'enyi measure aways satisfies the standard monogamy of entanglement for
, and only violates a high order monogamy inequality, in the rare
cases in which the strong superadditivity is also violated. The sates
numerically found where the violation occurs have special symmetries where both
inequalities are equivalent. We also show that every measure satisfing monogamy
for high dimensional systems also satisfies the strong superadditivity
inequality. For the case of R\'enyi measure, we provide strong numerical
evidences that these two properties are equivalent.Comment: replaced with final published versio
Capacitive Coupling of Two Transmission Line Resonators Mediated by the Phonon Number of a Nanoelectromechanical Oscillator
Detection of quantum features in mechanical systems at the nanoscale
constitutes a challenging task, given the weak interaction with other elements
and the available technics. Here we describe how the interaction between two
monomodal transmission-line resonators (TLRs) mediated by vibrations of a
nano-electromechanical oscillator can be described. This scheme is then
employed for quantum non-demolition detection of the number of phonons in the
nano-electromechanical oscillator through a direct current measurement in the
output of one of the TLRs. For that to be possible an undepleted field inside
one of the TLR works as a amplifier for the interaction between the mechanical
resonator and the remaining TLR. We also show how how the non-classical nature
of this system can be used for generation of tripartite entanglement and
conditioned mechanical coherent superposition states, which may be further
explored for detection processes.Comment: 6 pages, 5 figure
ANALITYCAL SOLUTION OF THE ONE DIMENSIONAL NONLINEAR TRANSIENT HEAT CONDUCTION PROBLEM USING GREEN’S FUNCTIONS
Analytical solutions showed to be an important and strong tool for understand thermal problems using mathematic tools. In this work we propose an approach about one dimensional analytical solution for a nonlinear transient heat conduction problem, were used mathematical elements such as Kirchhoff transformation, Green’s functions and the combination of them.  The combination of this two methods showed that was possible to determinate an analytical solution for the nonlinear thermal problem, and showed a good approximation when compared with results from numerical methods
Boltzmann-Gibbs thermal equilibrium distribution for classical systems and Newton law: A computational discussion
We implement a general numerical calculation that allows for a direct
comparison between nonlinear Hamiltonian dynamics and the Boltzmann-Gibbs
canonical distribution in Gibbs -space. Using paradigmatic
first-neighbor models, namely, the inertial XY ferromagnet and the
Fermi-Pasta-Ulam -model, we show that at intermediate energies the
Boltzmann-Gibbs equilibrium distribution is a consequence of Newton second law
(). At higher energies we discuss partial agreement
between time and ensemble averages.Comment: New title, revision of the text. EPJ latex, 4 figure
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