El programa de Posgrado en Fisica invita a todos para la:

Sustentación de Tesis

Diego Fernando Silva Sousa

CARACTERIZAÇÃO DA BLENDA DOADORA P3HT:CoPc PARA APLICAÇÕES EM DISPOSITIVOS FOTOVOLTAICOS

Jurados:

Prof. Dr. Ivan Helmuth Bechtold – (presidente) – UFSC/FSC

Prof. Dr. Roberto Mendonça Faria – (miembro externo) – IFUSP/São Carlos

Prof. Dr. Douglas José Coutinho – (miembro suplente) – UTFPR

Profª. Drª. Françoise Toledo Reis – (membro titular) – UFSC/FSC

Prof. Dr. Leonardo Negri Furini – (miembro titular) – UFSC/FSC

Profª. Drª. Marta Elisa Rosso Dotto – (miembro suplente) – UFSC/FSC

Profª. Drª. Juliana Eccher – (miembro suplente) – UFSC/FSC

Fecha: 14 de diciembre de 2021 – martes – Horario: 2:00 pm – Lugar: sala virtual Conferência Web de la Rede Nacional de Ensino e Pesquisa (RNP)

Enlace de acceso a sala virtual: https://conferenciaweb.rnp.br/webconf/ivan-helmuth

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

EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:

Gauge invariant quantum thermodynamics: consequences for the first law

Prof. Dr. Lucas Chibebe Céleri

Instituto de Física – UFG

Resumen:

Universality of classical thermodynamics rests on the central limit theorem, due to which measurements of thermal fluctuations are unable to reveal detailed information regarding the microscopic structure of a macroscopic body. When small systems are considered and fluctuations become important, thermodynamic quantities can be understood in the context of classical stochastic mechanics. A fundamental assumption behind thermodynamics is therefore that of coarse-graining, which stems from a substantial lack of control over all degrees of freedom. However, when quantum systems are concerned, one claims a high level of control. As a consequence, information theory plays a major role in the identification of thermodynamic functions. Here, drawing from the concept of gauge symmetry, essential in all modern physical theories, a new, intermediate, route is put forward. Working within the realm of quantum thermodynamics, a physically motivated gauge transformation, which encodes a gentle variant of coarse-graining behind thermodynamics, is explicitly constructed . As a consequence, quantum work and heat are reinterpreted, as well as the role of quantum coherence.

Fecha: 5 de noviembre de 2021 – (viernes) – Horário: 10:15 a.m.

Enlace acceso al canal de youtube: https://youtu.be/ieeh_LtXBgI

EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:

Virtual-Slit Focusing in a Cycloidal Mass Spectrometer – A Proof of Concept

Dr. Rafael Bento Serpa

Postdoctoral Associate | Duke University Nanomaterials and Thin Films Lab

Resumen:

This work demonstrates a novel approach to mass spectrometry using the “virtual-slit” created by the small, spatial volume from which ions are generated by localized ionization techniques (e.g., laser ionization of particles and surfaces, and spark ionization). That is, the volume in which the ions are generated creates a localized source of ions in much the same way as a slit that allows only ions from a specific cross-sectional area to pass. As demonstrated in this work, the unique perfect focusing properties of a cycloidal mass analyzer can enable the localized ionization volume to function as a virtual slit. In this manuscript, we provide a proof-of-concept (POC) demonstration of a virtual-slit cycloidal mass spectrometer (VS-CyMaS) consisting of a cycloidal mass analyzer, a laser ionization source, and an ion array detector. The laser is used to ionize either bulk or thin-film samples of Cu, Ti, Ni, and Cr. Results indicate that the width of the peaks at the detector is the same as the laser spot size, validating the concept of virtual-slit focusing. Furthermore, the material ablated with each laser pulse for Ti and Cu is estimated at 60 and 140 fg, respectively, indicating that a very low detection limit is possible given the ability of the cycloidal mass analyzer to collect ions generated by laser ionization that have wide energy and angular dispersions.

Fecha: 29 de octubre de 2021 – (viernes) – Horário: 10:15 a.m.

Enlace acceso al canal de youtube: https://youtu.be/t75RNYAdy1s

Sustentación de Tesis

Everton Botan

IDENTIFICAÇÃO DE ESTRELAS VARIÁVEIS NO VVV E INVESTIGAÇÃO DE ESTRUTURAS NO BOJO GALÁCTICO 

Jurados:

Prof. Dr. Roberto Kalbusch Saito – (presidente) – UFSC/FSC

Prof. Dr. Jacques Raymond Daniel Lepine – (miembro externo) – IAG/USP

Prof. Dr. Helio Jaques Rocha-Pinto – (miembro externo) – Observatório do Valongo – UFRJ

Prof. Dr. Daniel Ruschel Dutra – (membro titular) – UFSC/FSC

Prof. Dr. Antônio Nemer Kanaan Neto – (miembro titular) – UFSC/FSC

Fecha: 29 de octubre de 2021 – viernes – Horario: 9:30 am – Lugar: videoconferencia

Enlace de acceso a sala virtual: https://meet.google.com/dof-hsws-ezf

EL PROGRAMA DE POSGRADO EN FÍSICA invita a todos para lo seminario:

Aberration and Doppler effect on the CMB: kinematical and intrinsic contributions

Dr. Omar Roldán

Pós-doutorando – UFRJ

Resumen:

The aberration and Doppler coupling effects of the Cosmic Microwave Background (CMB) were measured by the Planck satellite. The most straightforward interpretation leads to a direct detection of our peculiar velocity, consistent with the measurement of the well-known dipole. We show however, that in some cases a primordial dipolar potential can also produce such effects. But in addition it produces other signatures due to integrated terms which we will discuss in some detail. We also discuss how aberration measurements can be used to constraint some models which introduce super-horizon perturbations to explain the hemispherical asymmetry. This work has also been used to infer the Intrinsic Dipole. Finally we also discuss about CMB anisotropies at all orders and the non-linear Sachs-Wolfe formula.

Fecha: 22 de octubre de 2021 – (viernes) – Horário: 10:15 a.m.

Enlace acceso al canal de youtube: https://youtu.be/sqea8-jX35Q