Seminar 5 - Santiago G. Gaitán , "Optical linear polarimetry in astrophysics"

25 Outubro 2023, 14:00 • Maria Margarida Cruz

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Abstract:  Polarimetry of the light provides unique insights into multiple astrophysical processes in the Universe that cannot be inferred from usual intensity observations. In this talk we review the importance of optical polarimetry in three different astrophysical systems: i) active galactic nuclei: supermassive black holes surrounded by accretion disks at the center of major galaxies, ii) kilonovae: the optical emission of compact neutron star mergers that are preceded by gravitational wave emission, and iii) supernovae: the explosive end of massive stars or of white dwarfs in binary systems. We discuss how different theoretical models of the progenitor and physical processes of these systems shape the predicted optical linear polarimetry and compare them to current observations. We pay particular attention to the systematic bias of interstellar polarization from dust in the line of sight.

Seminar 4 - Matthieu Labousse, "Soft violation of Bell's inequality"

18 Outubro 2023, 14:00 • Maria Margarida Cruz

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Abstract:  Walking drops on Faraday waves are one of the rare examples of non-quantum wave-particle duality. A series of striking experiments with one walking drop has led to behaviors that were thought to be the peculiar to the quantum scale. I will present a recent numerical and experimental investigation involving the coupling of two walking drops. To our great surprise, we found that the statistical behavior of this system shares some non-expected features of collective emission of photons in quantum optics, including superradiance and violation of Bell's inequality.

Seminar 3 - Bruno Romeira, "Brain-inspired nanophotonic spike-based sensing and computing"

11 Outubro 2023, 14:00 • Maria Margarida Cruz

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Seminar 2 - Cristovão Dias, "What’s the matter with active matter?"

4 Outubro 2023, 14:00 • Maria Margarida Cruz

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Seminar Abstract:  Active matter, a fascinating class of non-equilibrium systems, presents a plethora of phenomena that distinguish them from passive systems. In this seminar, we delve into the unique characteristics of active matter and explore how the raised theoretical and computational challenges are being addressed.
One of the central themes of this seminar will be the influence of complex environments on the dynamics of active matter. We will explore how spatial confinement, obstacles, and external fields can significantly impact the emergent behaviors of active agents. Moreover, we will discuss the fascinating feedback loops where active matter can dynamically alter its surroundings, leading to a deeper understanding of the intricate interplay between the agents and their environment.

Seminar 1 - Luís Ducla Soares, "Light Field Imaging for Immersive Systems"

27 Setembro 2023, 14:00 • Maria Margarida Cruz

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Seminar Abstract:  Light field imaging has received great attention recently due to its ability to provide high-fidelity visual capture and interactive visual experience based on rich spatio-angular light ray representations. Many tech giants investing in immersive display technologies have pointed towards the power of light field imaging for achieving ultra-realistic visual experiences, in which a user can walk into a real scene, freely move his/her head with the called Six Degrees of Freedom (6-DoF), and realistically perceive every little detail about the materials and lighting. In this context, new prototype systems have been proposed for capturing, processing, and rendering light fields. Moreover, the recent advent of high-quality consumer Head Mounted Displays (HMD) with positional head tracking, and autostereoscopic light field displays provide novel and compelling opportunities for visualizing light fields in new commercial media applications. In addition, the consumers can already have a glimpse of the light field capturing systems capabilities with the multi-camera smartphones that have been recently launched. However, systems for light field imaging face unique challenges due in part to the large volume of data that must be captured, processed, and displayed. Although various efforts have been recently initiated, mainly for still light field images, there are still many open questions for enabling ultra-realistic and interactive light field visual experiences. This talk will present some of the challenges on light field processing and discuss the recent advances in this field.