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Invariant PDEs with Two-dimensional Exotic Centrally Extended Conformal Galilei Symmetry
Get PDFConformal Galilei Algebras labeled by (where is the number of space dimensions and denotes a spin- representation w.r.t. the subalgebra) admit two types of central extensions, the ordinary one (for any and half-integer ) and the exotic central extension which only exists for and .\parFor both types of central extensions invariant second-order PDEs with continuous spectrum were constructed in \cite{AKS}. It was later proved in \cite{AKT1} that the ordinary central extensions also lead to oscillator-like PDEs with discrete spectrum.\parWe close in this paper the existing gap, constructing \textcolor{black}{a new class of second-order invariant PDEs for the exotic centrally extended CGAs; they admit a discrete and bounded spectrum when applied to a lowest weight representation}. These PDEs are markedly different with respect to their ordinary counterparts. The case (which is the prototype of this class of extensions, just like the Schr\"odinger algebra is the prototype of the ordinary centrally extended CGAs) is analyzed in detail. 
Current algebra for the two-site Bose-Hubbard model
Get PDFAbstract: We present a current algebra for the two-site Bose-Hubbard model and use it to get the quantum dynamics of the currents. For different choices of the Hamiltonian parameters we get differentcurrents dynamics. We generalize the Heisenberg equation of motion to write the second derivativeof an operator
Bethe states for the two-site Bose-Hubbard model: a binomial approach
Get PDFAbstract: We calculate explicitly the Bethe vectors states by the algebraic Bethe ansatz methodwith the gl(2)-invariant R-matrix for the two-site Bose-Hubbard model. Using a binomialexpansion of the n-th power of a sum of two operators we get and solve a recursion equation.We calculate the scalar product and the norm of the Bethe vectors states. The form factorsof the imbalance current operator are also computed. 
Thermostatistics of a damped bi-modal particle
Get PDFWe study the thermostatistics of a damped bi-modal particle, i.e., a particle of mass msubject to a work reservoir that is analytically represented by the telegraph noise. Because ofthe coloured nature of the noise, this system does not t the Levy-It^o class of stochastic processesmaking of it an instance of a non-equilibrium system in contact with an external reservoir. Weobtain the statistics for the position and velocity, namely in the steady state, as well as the (timedependent) statistics of the energy uxes in the system considering no constraints on the noisefeatures. With that results we are able to give an account of the statistical features of the largedeviations of the injected and dissipated power that can change from sub-Gaussianity to super-Gaussianity depending on the colour of the noise. By properly dening an effective temperaturefor this system, T , we are capable of obtaining an equivalent entropy production/exchange rateequal to the ratio between the dissipation of the medium, and the mass the particle, a relationthat concurs with the case of a standard thermal reservoir at temperature, T = T
Processamento digital de imagens: conceitos fundamentais
Get PDFA proposta deste trabalho é fornecer um material conciso sobre processamento de imagens, já que o uso de técnicas de imageamento é uma realidade em vários ramos da física. Com essa proposta em mente, são apresentados os principais conceitos da área de processamento digital de imagens: representação digital de imagens, filtragem, segmentação labeling e data clustering. Adicionalmente, o conteúdo é finalizado com uma apresentação sucinta da morfologia matemática. Visando dar o mínimo de suporte prático, algumas aplicações em MATLAB® são expostas. 
Hyperfine Interactions Measurements in Hydroxiapatite : Considerations and Perspectives
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Data Acquisition with Optimal Pulse Amplitude Estimation for a Neutrino Detection Experiment
Get PDFA data acquisition system for the Angra antineutrino detector is under development. The system isable to digitize, to process and to store the analog signals coming from photomultiplier tubes (PMT), after thefront-end electronics. We present here the design of a VME-based data acquisition module which is part ofthe Angra DAQ as well as the Muon Electronics in the Double Chooz experiment. This module features eightanalog-to-digital channels, running at 125 MHz sampling frequency. In order to measure time between PMTpulses, an 82 ps time-to-digital converter is included. A Field Programmable Gate Array is used to implementdigital signal processing algorithms on the digitized data, where a FIR filter for optimal pulse amplitude estimationhas been implemented. The design and preliminary results with single-photoelectron measurements arepresented
Four types of (super)conformal mechanics: D-module reps and invariant actions
Get PDF(Super)conformal mechanics in one dimension is induced by parabolic or hyperbolic/trigonometrictransformations, either homogeneous (for a scaling dimension ) or inhomogeneous (at , with an inhomogeneity parameter). Four types of inequivalent(super)conformal actions are thus obtained. With the exclusion of the homogeneous parabolic case, dimensional constants are present. \parBoth the inhomogeneity and the insertion of generalize the construction of Papadopoulos [CQG 30 (2013) 075018; arXiv:1210.1719].\parInhomogeneous -module reps are presented for the superconformal algebras ,, and . For centerless superVirasoro algebras -module reps are presented(in the homogeneous case for ; in the inhomogeneous case for ).\parThe four types of superconformal actions are derived for systems. When , the homogeneously-induced actions are -invariant ( is critically linked to ); the inhomogeneously-induced actions are -invariant.\parIn , for a single bosonic field, the homogeneous transformations induce a conformally invariant power-law action, while the inhomogeneous transformations induce the conformally invariant Liouville action. 
A bosonic multi-state two-well model
Get PDFAbstract: Inspired by the increasing possibility of experimental control in ultracoldatomic physics we introduce a new Lax operator and use it to construct andsolve models with two wells and two on well states together with its generalization forn on well states. The models are solved by the algebraic Bethe ansatz method andcan be viewed as describing two Bose-Einstein condensates allowing for an exchangeinteraction through Josephson tunneling
Cientistas de farda: a presença de militares professores no CBPF
Get PDFO objetivo principal deste artigo é analisar o envolvimento de militares com pesquisa e ensino no CBPF, iniciado em meados dos anos 1950. Através das passagens do general Argus Ourique Moreira e do coronel Antonio José Duffles de Amarante pelo Centro, concomitantemente aos seus vínculos a instituições e projetos de pesquisa militares, percebemos uma circulação de ideias, projetos e instrumentos científicos que pode ser entendida como uma tentativa de alinhamento entre as estruturas militar e científica no Brasil. Além disso, através da análise da circulação institucional dos homens de farda aqui citados, é possível comparar as características de ensino e pesquisa no meio civil e no meio militar. O conjunto de elementos que analisamos leva-nos à conclusão de que a presença de militares em projetos de pesquisa no CBPF se justifica por um papel muito mais de execução e de apoio a investigações realizadas por físicos do Centro do que o de uma participação eminentemente criadora e/ou inventiva por parte dos militares