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showing 10 items of 2156 documents
Propagation and Stability of Novel Parametric Interaction Solitons
2006
International audience; We present a new multi-parameter family of analytical soliton solutions for nonlinear three-wave resonant interactions. We show the amplitude, phase-front shapes and general properties of the solitons. The stability of these novel parametric solitons is simply related to the value of their common group velocity.
2N+1 highest amplitude of the modulus of the N-th order AP breather and other 2N-2 parameters solutions to the NLS equation
2015
We construct here new deformations of the AP breather (Akhmediev-Peregrine breather) of order N (or AP N breather) with 2N −2 real parameters. Other families of quasi-rational solutions of the NLS equation are obtained. We evaluate the highest amplitude of the modulus of AP breather of order N ; we give the proof that the highest amplitude of the AP N breather is equal to 2N + 1. We get new formulas for the solutions of the NLS equation, different from these already given in previous works. New solutions for the order 8 and their deformations according to the parameters are explicitly given. We get the triangular configurations as well as isolated rings at the same time. Moreover, the appea…
Cross-diffusion driven instability for a Lotka-Volterra competitive reaction-diffusion system
2008
In this work we investigate the possibility of the pattern formation for a reaction-di®usion system with nonlinear di®usion terms. Through a linear sta- bility analysis we ¯nd the conditions which allow a homogeneous steady state (stable for the kinetics) to become unstable through a Turing mechanism. In particular, we show how cross-di®usion e®ects are responsible for the initiation of spatial patterns. Finally, we ¯nd a Fisher amplitude equation which describes the weakly nonlinear dynamics of the system near the marginal stability.
Nonlinear higher-order polariton topological insulator
2020
We address the resonant response and bistability of the exciton-polariton corner states in a higher-order nonlinear topological insulator realized with kagome arrangement of microcavity pillars. Such states are resonantly excited and exist due to the balance between pump and losses, on the one hand, and between nonlinearity and dispersion in inhomogeneous potential landscape, on the other hand, for pump energy around eigen-energies of corresponding linear localized modes. Localization of the nonlinear corner states in a higher-order topological insulator can be efficiently controlled by tuning pump energy. We link the mechanism of corner state formation with symmetry of the truncated kagome…
Effect of a columnar defect on the shape of slow-combustion fronts
2003
We report experimental results for the behavior of slow-combustion fronts in the presence of a columnar defect with excess or reduced driving, and compare them with those of mean-field theory. We also compare them with simulation results for an analogous problem of driven flow of particles with hard-core repulsion (ASEP) and a single defect bond with a different hopping probability. The difference in the shape of the front profiles for excess vs. reduced driving in the defect, clearly demonstrates the existence of a KPZ-type of nonlinear term in the effective evolution equation for the slow-combustion fronts. We also find that slow-combustion fronts display a faceted form for large enough e…
Peripheral CB1 receptor blockade acts as a memory enhancer through an adrenergic-dependent mechanism
2021
Peripheral inputs to the brain continuously shape its function and can influence the formation of non-emotional memory, but the underlying mechanisms have not been fully understood. Cannabinoid type-1 receptors (CB1R), widely distributed in the organism, is a well-recognized player in memory performance, and its systemic modulation significantly influences memory function. By assessing non-emotional memory in mice, we have now found a relevant role of peripheral CB1R in the formation of persistent memory. Indeed, peripherally restricted CB1R antagonism by using AM6545 showed a mnemonic effect that was occluded in adrenalectomized mice, after peripheral adrenergic blockade, or when vagus ner…
Et sant og ekte liv i en falsk og narkoman verden - Begjær, produksjon og identitet i Thure Erik Lunds Myrbråtenfortellinger (1999-2005)
2011
Author's version of an article published in the journal: Edda. Also available from the publisher at: http://www.idunn.no/ts/edda/2011/03/art08 Thure Erik Lund’s Myrbråten stories may be read as grim and funny descriptions of (post)modern Norway – anatomies made by means of highly ideosyncratic style(s). The postmodern condition is ridiculed along with the regressive utopias it engenders. The essay highlights the terms of subject formation in a society where traditional values and social forms have given way to forces of the marked. By way of Deleuze and Guattari’s coupling in L’Anti-Œdipe of schizophrenia, desire and production, it is possible to discern a strategy for emancipation in Myrbr…
Cuckoo's Eggs in Neutron Stars: Can LIGO Hear Chirps from the Dark Sector?
2018
We explore in detail the possibility that gravitational wave signals from binary inspirals are affected by a new force that couples only to dark matter particles. We discuss the impact of both the new force acting between the binary partners as well as radiation of the force carrier. We identify numerous constraints on any such scenario, ultimately concluding that observable effects on the dynamics of binary inspirals due to such a force are not possible if the dark matter is accrued during ordinary stellar evolution. Constraints arise from the requirement that the astronomical body be able to collect and bind at small enough radius an adequate number of dark matter particles, from the requ…
Off-line studies of the laser ionization of yttrium at the IGISOL facility
2007
A laser ion source is under development at the IGISOL facility, Jyvaskyla, in order to address deficiencies in the ion guide technique. The key elements of interest are those of a refractory nature, whose isotopes and isomers are widely studied using both laser spectroscopic and high precision mass measurement techniques. Yttrium has been the first element of choice for the new laser ion source. In this work we present a new coupled dye-Ti:Sapphire laser scheme and give a detailed discussion of the results obtained from laser ionization of yttrium atoms produced in an ion guide via joule heating of a filament. The importance of not only gas purity, but indeed the baseline vacuum pressure in…
Can one ever prove that neutrinos are Dirac particles?
2017
According to the "Black Box" theorem the experimental confirmation of neutrinoless double beta decay ($0 \nu 2 \beta$) would imply that at least one of the neutrinos is a Majorana particle. However, a null $0 \nu 2 \beta$ signal cannot decide the nature of neutrinos, as it can be suppressed even for Majorana neutrinos. In this letter we argue that if the null $0 \nu 2 \beta$ decay signal is accompanied by a $0 \nu 4 \beta$ quadruple beta decay signal, then at least one neutrino should be a Dirac particle. This argument holds irrespective of the underlying processes leading to such decays.