11,638 research outputs found
Teoria quase-linear de Kato e a KdV transicional
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina. Centro de Ciências Físicas e Matemáticas.Neste trabalho desenvolvemos a teoria linear e quase-linear de T. Kato e fazemos uma aplicação à equação de Korteweg-de Vries transicional (t-KdV), mostramos que o problema de Cauchy associado a esta equação tem solução única local nos espaços de Sobolev usuais
Estudo de invariantes em sistemas dinamicos continuos e não-lineares
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina. Centro de Ciencias Fisicas e MatematicasNo presente trabalho investigamos vários aspectos relacionados com a existência de invariantes em sistemas dinâmicos contínuos e não-lineares. Apresentamos relações de recorrência para gerar os termos presentes nas densidades e fluxos da equação de Korteweg-de Vries e nas densidades da equação modificada de Korteweg-de Vries. Nossas relações são baseadas na observação empírica de que, para um dado rank r, o conjunto {P2r} de todas as partições do inteiro 2r contém todos os monômios de {Xr-1} e {Tr}. As relações são facilmente implementáveis em máquinas capazes de efetuar manipulações algébricas. Obtivemos, através de nossas relações de recorrência, quatro novos invariantes para a equação de Korteweg-de Vries e três para a equação modificada de Korteweg-de Vries. Testamos a validade de conjecturas estabelecidas recentemente por Torriani usando análise combinatorial. Além disso, analisamos três métodos encontrados na literatura recente para a obtenção de constante de movimento de equações de evolução não-lineares. São eles: uma relação entre constantes de movimento e equações variacionais; um procedimento para a obtenção de constantes de movimento associadas a cada simetria de Lie da equação diferencial que descreve o sistema; e a obtenção de novas constantes a partir de constantes conhecidas usando os operadores das transformações infinitesimais que deixam a equação de evolução invariante. São feitas aplicações destes métodos a equações conhecidas com ênfase em física atômica e óptica quântica
Cylindrical nonlinear Schroedinger equation versus cylindrical Korteweg-de Vries equation
No full textA correspondence between the family of cylindrical nonlinear
Schrodinger (cNLS) equations and the one of cylindrical
Korteweg-de Vries (cKdV) equations is constructed. It associates
non stationary solutions of the first family with the ones of the
second family. This is done by using a correspondence, recently
found, between the families of generalized NLS equation and
generalized KdV equation, and their solutions in the form of
travelling waves, respectively. In particular, non-stationary
soliton-like solutions of the cNLS equation can be associated with
non-stationary soliton-like solutions of cKdV equation
Korteweg-de Vries equation and energy sharing in Fermi-Pasta-Ulam
No full textWe address the problem of equipartition in a long Fermi-Pasta-Ulam (FPU) chain. After giving a precise relation between FPU and Korteweg-de Vries we use the latter equation to show that, corresponding to initial data a la Fermi, the time average of the energy on the kth mode decreases exponentially with k/N. The result persists in the thermodynamic limit
Some mathematical aspects of the correspondence between the generalized nonlinear Schroedinger equation and the generalized Korteweg-de Vries equation
No full textA review of the recent studies on the correspondence between a wide family of the generalized nonlinear Schrodinger equations and a wide family of the generalized Korteweg-de Vries equations is presented. It was constructed some years ago within the framework of a recently-developed approach based on the Madelung's fluid representation of the generalized nonlinear Schrodinger equation. The present analysis extends the former approach, developed for nonlinear Schrodinger equation with a nonlinear term proportional to a multiplicative operator, to the cases of derivative operators and the ones corresponding to cylindrical nonlinear Schrodinger equations
Measurement of CP asymmetry in D-0 -> K- K+ and D-0 -> pi(-) pi(+) decays
No full textTime-integrated CP asymmetries in D 0 decays to the final states K - K + and π - π + are measured using proton-proton collisions corresponding to 3fb-1 of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D 0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be Δ ACP = ACP (K- K +) ACP (π- π+) = (+ 0.14 ± 0.16 (stat) ± 0.08 (syst)) %. A measurement of A CP (K - K +) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be ACP (K- K+) = (- 0.06 ± 0.15 (stat) ± 0.10 (syst)) %, where the correlation coefficient between ΔA CP and A CP (K - K +) is ρ = 0.28. By combining these results, the CP asymmetry in the D 0 → π - π + channel is A CP (π - π +) = (-0.20 ± 0.19 (stat) ± 0.10 (syst))%. [Figure not available: see fulltext.] © 2014 The Author(s)
Measurement of the branching fractions of the decays D+ -> K-K+K+, D+ -> pi-pi(+) K+ and D-s(+) -> pi-K+K+
No full textThe branching fractions of the doubly Cabibbo-suppressed decays D + → K − K + K + , D + → π − π + K + and D s+ → π − K + K + are measured using the decays D + → K − π + π + and D s+ → K − K + π + as normalisation channels. The measurements are performed using proton-proton collision data collected with the LHCb detector at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2.0 fb −1 . The results areB(D+→K−K+K+)B(D+→K−π+π+)=(6.541±0.025±0.042)×10−4,B(D+→π−π+K+)B(D+→K−π+π+)=(5.231±0.009±0.023)×10−3,B(Ds+→π−K+K+)B(Ds+→K−K+π+),=(2.372±0.024±0.025)×10−3, where the uncertainties are statistical and systematic, respectively. These are the most precise measurements up to date. [Figure not available: see fulltext.]
- …
