Resumo: Há cinquenta anos, um trabalho seminal de Stephen Hawking foi publicado na revista Nature. Nele, foi-se anunciada a radição emitida por buracos negros que levaria o nome do autor. Desde então, o fenômeno foi intensamente estudado por inúmeros autores e influenciou diversos campos da física teórica. Neste colóquio, exploramos a relevância da descoberta e algumas das repercussões que ainda hoje são estudadas. Daremos ênfase a avanços recentes na termodinâmica de buracos negros, ao chamado "paradoxo da informação" e ao relacionado "paradoxo do tempo de Page".
Abstract: In this talk I would like to discuss the defect renormalization group flows recently found in ABJM theory. In such a setting, we find RG flow trajectories that may or may not preserve some subset of the original N=6 supersymmetry. The $\beta$-functions have a rich spectrum of fixed points representing (super)conformal defects that provide a rich arena to study quantum effects in 2+1 dimensional theories. This sheds new light on universal information about the theory, such as the Bremsstrahlung function, and possibly on the holographic dual setting of strings in AdS4xCP3.
Resumo: Gravitational-wave interferometers can be used to probe the existence of dark matter. Different types of dark matter, such as sub-solar primordial black holes, axions and dark photons, could leave different imprints on gravitational-wave detectors. While arising from physically different sources, such signals share common traits, and can be searched for with similar methods. In this talk, I will explain how persistent, quasi-monochromatic signals in ground-based detectors could arise from each of the aforementioned dark matter candidates. I also describe some of our search methods and summarize results from the most recent observing runs of Advanced LIGO, Virgo, and KAGRA.
Resumo: Given the exponential growth on the upcoming supernovae data available, the possibilities of rigorously testing the cosmological principle becomes ever more real. One of the ways to do so is by measuring the multipole decomposition of the Hubble and deceleration parameters. In this presentation, I will discuss the observational-theoretical approach, initially introduced by Kristian & Sachs, which allows for the interpretation of data in non-homogeneous and anisotropic universes. I will also explore the effects introduced by the relative motion between the observer and the reference frame defined by galaxies (the matter frame), demonstrating that the luminosity distance should be corrected in such cases.