Agosto 2013 – enero 2014

El seminario se lleva a cabo en el Auditorio de la Facultad de Ciencias.

13 de septiembre, 4:00pm

Calculation of photon-graviton amplitudes and the worldline formalism

Olindo Corradini
UNACH

Abstract: We give a pedagogical introduction to the use of relativistic particle actions in the computation of Quantum Field Theory Feynman diagrams involving external photons, gluons and gravitons; the so-called “worldline formalism”. Canonical quantization, as well as path integrals for the above models, will be discussed. We will point out the role that symmetries –especially worldline local symmetries– play in such technique.

27 de septiembre, 4:00pm

Patrones de campo lejano de soluciones de la ecuación de Helmholtz

Emilio Marmolejo
IMATE-UNAM

Resumen: Los patrones de campo lejano son funciones que describen el comportamiento asintótico de soluciones de la ecuación de Helmholtz radiantes. Estas funciones están definidas en L^2 de la esfera unitaria de tres dimensiones, con un cierto decaimiento y se usan mucho para problemas inversos de dispersión. Presentaremos primero una introducción a los resultados más importantes alrededor de la ecuación de Helmholtz y de los patrones de campo lejano. Después veremos una generalización de estos resultados a funciones definidas en una álgebra de Clifford.

11 de octubre, 4:00pm

Root finding methods for perturbed orthogonal polynomials

Edmundo Huertas
Universidade de Coimbra

Abstract: This seminar is focused on the behavior of zeros of sequences of orthogonal polynomials, associated with “classical” (i.e. Laguerre, Jacobi, Hermite) measures and other “modified” measures, perturbed with the simultaneous addition of m atomic measures (Dirac deltas).

First we introduce the electrostatic interpretation of the zero distribution for classical orthogonal polynomials as equilibrium points in a logarithmic potential interaction, under the action of an external field. Next, we describe a mass-point perturbation of a measure with unbounded support, in particular the Laguerre measure, and the polynomials orthogonal with respect to such modified measure, the so called Laguerre-type orthogonal polynomials. Finally we study the behavior of the zeros of the Laguerre-type orthogonal polynomials, and we analyze such an equilibrium problem when the m mass points are located in the exterior of the support of the classical measure.

25 de octubre, 4:00pm

Status of neutrino mass and implications for dark matter

José Valle
Instituto de Física Corpuscular, Universidad de Valencia & CSIC

Abstract: The status of neutrino mass experiments is reviewed as well as their theoretical and cosmological implications, especially for dark matter.

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