Noticimat: 11

Coloquio

Miércoles 17 de marzo

Titulo: Light in a left-handed world
Ponente: Prof. Ildar Gabitov, Mathematics Department, University of Arizona
Lugar: Salón Diego Bricio Hernández
Hora: 16:15 hrs.

Resumen: While a negative refractive index (NRI) has not been found in naturally occurring materials owing to the limitations imposed by atoms and molecules, it has been theoretically predicted and experimentally demonstrated that a NRI can be realized in metamaterials.

Metamaterials are built of artificial or meta atoms that are deliberately engineered resonant nanostructures bringing new degrees of freedom to design of functional materials.

The electrical permittivity and the magnetic permeability (normally not a factor at optical frequencies) of metamaterials can, in principle, be designed to be positive, negative or even zero at as needed by properly adjusting the dimensions, periodicity and other properties of the meta-atoms.

Therefore, metamaterials can fundamentally change both linear and nonlinear light-matter interactions by bringing the magnetic component of the field into play in addition to its electric component and thus making electromagnetic waves ambidextrous" in the optical domain.

One of the most remarkable phenomena that take place at a positive-negative index material interface is that the right-handed triplet of vectors consisting of the electric and magnetic fields and the wave vector (E;H; k) undergoes a discontinuous change. From a topological viewpoint, a left-handed triplet cannot be transformed into a right-handed triplet by a continuous transformation. However, dielectric permittivity and magnetic permeability can be changed from positive to negative values as continuous functions of the coordinate in the direction normal to the interface.

The fact that continuously changing material characteristics can lead to a topologically critical phenomenon must be reected in the transitional characteristics of the electromagnet waves traversing the interface.

Seminario de Matemáticas Aplicadas

Martes 16 de marzo

Titulo: Gross Impact from Slim Chances: Errors in Optical Communications
Ponente: Prof. Ildar Gabitov, Mathematics Department, University of Arizona
Lugar: Salón de usos múltiples del nivel H
Hora: 11:00 hrs.

Resumen: Realization of an extremely rare event can lead to enormous consequences. Examples include earthquakes, meteor impacts or genetic mutations. Understanding of the underlying statistical properties of Duch events is of great importance. However, investigation of these problems is very hard. The events are very rare and therefore it is extremely difficult to collect sufficient statistical data.   We will address the problem of errors in information transmission through optical fibers as an example of such a rare event. Current limits for acceptable error rates in optical information systems allow approximately one error per billion or thousand billion bits. These errors result from the combination of noise and structural disorder in the system. Evaluation of the statistics of such errors is an important practical problem. However, straightforward Monte-Carlo type simulations for such rare events are not practical. On the other hand, designing systems by trial and error where each system is built is prohibitively expensive.  In the framework of a mathematical model which we developed, we considered optical pulse (bit-carriers) dynamics in the presence of temporal system noise and structural disorder.
Using the operator integral approach invented by Feynman, we found an analytical formula characterizing the statistics of errors as a function of system parameters and noise/disorder characteristics. These theoretical findings were verified against experimental data obtained at the Optical Sciences Center of the University of Arizona.

Seminario de Computación

Viernes 19 de marzo

Titulo: Memorias asociativas bioinspiradas y sus aplicaciones en el reconocimiento de patrones
Ponente: Roberto Vázquez, Universidad La Salle
Lugar: Salón Diego Bricio Hernández
Hora: 12:30 hrs.

Prof. Ildar Gabitov, Mathematics Department, University of Arizona. (15 al 17 de Marzo). Cubículo I-9. Ext. 49655. Anfitrión: Dr. Jesús Adrián Espínola.

Del 15 al 19 de marzo se llevará a cabo el Taller de Modelos de Captura y Recaptura. Comité Organizador: Dr. José Miguel Ponciano.

Felicitaciones a Joaquín Peña Acevedo por la obtención del grado Doctor en Ciencias con Orientación en Ciencias de la Computación el pasado 9 de marzo con la tesis: Solución del Problema Inverso de Electroencefalografía Mediante Modelos de Fuentes Distribuidas por Regiones. Sinodales: Dr. Salvador Botello Rionda, Presidente; Dr. Mariano José Juan Rivera Meraz, Secretario; Dra. Thalía Harmony Baillet (UNAM), Vocal; Dr. José Luis Marroquín Zaleta, Vocal y Director de Tesis.

Felicitaciones a Guillermo Baqueiro Victorín por la obtención del grado de Maestro en Ciencias con Especialidad en Computación y Matemáticas Industriales el pasado 11 de marzo con la tesis: Calibración Externa de una Red de Cámaras Fijas Basada en Movimiento. Sinodales: Dr. Mariano José Juan Rivera Meraz, Presidente; Dr. Salvador Ruiz Correa, Secretario; Dr. Jean Bernard Hayet, Vocal y Director de Tesis.