EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:
Structured light for computation and light conversion
Dra. Nara Rubiano da Silva
Pós-doutoranda – GIQSul – UFSC
Resumen:
Structured light displays intricate field distributions (of intensity, phase, polarization) in space, with several emerging applications. In the Quantum Optics Laboratory at UFSC, we study classical and quantum processes utilizing such optical fields. In this talk, I will present two of our recent results in the classical regime. Firstly, we manipulate the phase of light for realizing a computational task, namely, a matrix-by-vector multiplication. Each matrix or vector element is mapped into the tranverse phase distribution of the light beam, and the required operations are realized by optical elements. I will introduce this optical processor and, as an example, its application to an optimization problem called unidimensional Distance Geometry Problem. In a second work, we investigate a fundamental aspect of employing structured beams of the Laguerre-Gauss family in stimulated parametric down-conversion. Specifically, we analyse the selection rules involving the radial order of the resulting LG beams, which I will discuss in my talk.
Fecha: 3 de deciembre de 2021 – (viernes) – Horário: 10:15 a.m.
Enlace acceso al canal de youtube: https://youtu.be/PHyzke71iHQ
El Programa de Posgrado en Física invita a todos para:
Examen de Cualificación al Doctorado
Carline Biesdorf
MODIFICAÇÕES NO MODELO DA SACOLA DO MIT E DIAGRAMAS DE FASES DA QCD
Jurados
Profª. Drª. Débora Peres Menezes – (presidente) – UFSC/FSC
Prof. Dr. Marcelo Dallagnol Alloy – (miembro titular) – UFSC/Blumenau
Prof. Dr. Luiz Laércio Lopes – (miembro externo) – CEFET/MG
Prof. Dr. Celso de Camargo Barros Junior – (miembro titular) – UFSC/FSC
Prof. Dr. Tiago José Nunes da Silva – (miembro titular) – UFSC/FSC
Fecha: 1 de diciembre de 2021– quarta-feira – Horario: 10:00 am – Lugar: a través de la plataforma Google Meet
Enlace de acceso a la sala virtual: https://meet.google.com/reu-rgkr-kct
EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:
Detailed chrono-chemo-dynamics of seven metal-poor red giants from Kepler
Arthur Alencastro Puls
Research School of Astronomy and Astrophysics, Australian National University
Resumen:
The Kepler mission has yielded a revolution in the field of GalacticArchaeology, with its photometry allowing the determination of stellar parameters with an unprecedented level of precision for Red Giant stars. Recent studies have shown that a few of these objects display conflicting characteristics in the age-metallicity space (e.g., young and metal-poor). In this project we combine asteroseismic information from solar-like oscillations, high-resolution spectroscopy and Gaia astrometry to derive stellar ages, chemical abundances and kinematics for a group of metal-poor Red Giants, and characterise them in a multidimensional chrono-chemo-dynamical space. Our results suggest that underestimated parallax errors make the effect of Gaia parallaxes more important than different choices of model grid or – in the case of stars ascending the RGB – mass-loss prescription. Two stars are identified as potentially evolved halo blue stragglers. Four objects are likely members of the accreted Milky Way halo, and their possible relationship with known accretion events, such as Gaia-Sausage and Gaia-Sequoia, is discussed.
Fecha: 26 de noviembre de 2021 – (viernes) – Horário: 10:15 a.m.
Enlace acceso al canal de youtube: https://youtu.be/D1pIcDUoHds
EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:
Chemistry in optical microcavities: Spectral fluctuations and energy transport
Prof. Dr. Raphael Ribeiro
Department of Chemistry, Emory University – Atlanta, USA
Resumen:
Optical cavities and metallic nanoparticles confine electromagnetic fields and enable new pathways to control physicochemical processes via strong light-matter interactions. In fact, recent experiments have shown that photonic and plasmonic materials may induce significant and sometimes unexpected changes to physical properties and reactivity of molecular systems. In this talk, I will introduce and present the key results of our recent theoretical investigations on the effects of collective radiation-matter interactions on transport and spectral properties of disordered molecular ensembles hosted by a resonant 1D optical cavity (photonic wire). The main implications of our findings to future theoretical and experimental research will be discussed. I will show that widely employed minimal theoretical models fail to adequately describe photonic effects on the local properties of chemical systems and explain strategies to maximize the influence of optical cavities on molecular materials informed by our simulations.
Fecha: 19 de noviembre de 2021 – (viernes) – Horário: 10:15 a.m.
Enlace acceso al canal de youtube: https://youtu.be/8nV3QDFmhB8
EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:
What Hampers Electron Transport in Organic Crystals? A Close Look at Band-like Transport in N-type Organic Semiconductors
Prof. Dr. Emanuele Orgiu
Institut National de la Recherche Scientifique – INRS, Québec – Canada
Resumen:
Charge transport in organic semiconductors is notoriously sensitive to the presence of disorder, both intrinsic and extrinsic, especially for n-type materials. Intrinsic dynamic disorder stems from large thermal fluctuations both in intermolecular transfer integrals and (molecular) site energies in weakly interacting van der Waals solids and sources transient localization of the charge carriers. The molecular vibrations that drive transient localization typically operate at low-frequency (< a-few-hundred cm-1), which makes it difficult to assess them experimentally. Hitherto, this has prevented the identification of clear molecular design rules to control and reduce dynamic disorder. In addition, the disorder can also be extrinsic, being controlled by the chemical and physical «coupling» of the π-conjugated core to the gate dielectric. During the Colloquium, I will present a comprehensive study of charge transport in two closely related n-type molecular organic semiconductors using a combination of temperature-dependent inelastic neutron scattering and photoelectron spectroscopy corroborated by electrical measurements, theory and simulations. By doing so, unambiguous evidence is provided that ad hoc molecular design enables to free the electron charge carriers from both intrinsic and extrinsic disorder to ultimately reach band-like electron transport.
Fecha: 12 de noviembre de 2021 – (viernes) – Horário: 10:15 a.m.
Enlace acceso al canal de youtube: https://youtu.be/TE3LD1NKi4c
