Seminars
 
CSIC
12/07/2019 - 00/00/0000
The 1908 Tunguska Event: 111 years after, it still makes you think
Sala Alberto Lobo (ICE building, UAB Campus)
On June 30th, 1908, an explosion flattened more than two thousands square kilometres of Siberian taigà. During the following 111 years, several theories were proposed to explain the observed features. Basically, there is a general agreement on the collision of the Earth with a cosmic body, but still today there are doubts on the exact dynamics of the phenomenon and the nature of the body (comet or asteroid?). Particularly, I will address the atmospheric fragmentation and the possibility of a ground impact.
UB
04/07/2019 - 00/00/0000
Search optimization and Dynamical Criticality on the String Landscape
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
A striking feature of our universe is its near criticality. The cosmological constant and weak hierarchy problems, as well as the metastability of the electroweak vacuum, can all be understood as problems of criticality. This suggests a statistical physics approach, based on the landscape of string theory.
UB
03/07/2019 - 00/00/0000
Black hole microstate cosmology
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
We consider states of holographic CFTs defined by modifying the standard disk path integral that gives the vacuum state with the insertion of a boundary. We argue that these states correspond to black hole microstates with a geometrical behind-the-horizon region, modelled by a portion of a second asymptotic region terminating at an end-of-the-world (ETW) brane.
CSIC
01/07/2019 - 00/00/0000
Bouncing solutions in modified gravity
L3-03 workshop room (ICE building, UAB Campus)
In this talk, I would like to discuss the modification of general relativity and why we need the modification. Subsequently, I will talk about the bouncing solutions in modified gravity. Bouncing problem is one of the fascinating parts of the study of cosmological dynamics in modified gravity because the big bang singularity could be avoided by a big bounce. The indication of the bouncing universe is: the size of the scale factor contracted to a finite volume.
CSIC
28/06/2019 - 00/00/0000
X-MRIs and IMRIs - From extremely large to intermediate
Sala Alberto Lobo (ICE building, UAB Campus)
The gravitational capture of a compact object by a supermassive black hole is the best probe of strong gravity we have thought of. I will present recent results that predict that such gravitational captures can be detected in the future with space-borne detectors right at our Galactic Centre with extreme signal-to-noise ratios and extremely large mass ratios, via the capture of sub-stellar objects. 
UB
28/06/2019 - 00/00/0000
A primer on Axtronomy
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
We briefly describe the detection of axion dark matter to discuss how an eventual detection can be used to do galactic astronomy and to study the properties of the axionic dark matter halo.
UB
27/06/2019 - 00/00/0000
Spacetimes, symmetries and theories: beyond lorentzian geometry
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
Spacetimes, like Minkowski space, are omnipresent in physics. I will introduce a recent classification of spacetimes that generalizes the classification of maximally symmetric Lorentzian geometries and includes further physically interesting ones.
CSIC
21/06/2019 - 00/00/0000
Simulating Pixels
Sala Alberto Lobo (ICE building, UAB Campus)
Pixel simulations are essential in several phases of a project as they provide mock data that allows us to design, test and optimize the analysis of the images, prior to the real observations. They are also key to evaluate the performance of a survey and help to understand the causes of unknown systematics once the mission starts.  
UB
20/06/2019 - 00/00/0000
Quantum-assisted Machine Learning in Near-Term Quantum Devices
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
With quantum computing technologies nearing the era of commercialization and quantum advantage, machine learning (ML) has been proposed as one of the promising killer applications. Despite significant effort, there has been a disconnect between most quantum ML proposals, the needs of ML practitioners, and the capabilities of near-term quantum devices towards a conclusive demonstration of meaningful quantum advantage in the near future.
UB
20/06/2019 - 00/00/0000
Constraints on the hadron-quark phase transition and the properties of twin stars with GW170817
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
Hybrid stars are compact stars that consist of a core of pure quark or mixed hadron-quark matter and outer layers of hadronic (or nuclear) matter. Depending on its features, the hadron-quark phase transition can lead to a separate mass-radius stable branch of hybrid stars and therefore to "twin-star" solutions, i.e. stars with similar masses and different radii.
UB
20/06/2019 - 00/00/0000
Particle acceleration in protostellar jets: an observational approach
Seminari DAM (724, ICCUB building, UB Campus)
Deeply embedded protostellar jets are well known to be dominated by the emission of thermal electrons. Interestingly, in the last decades, negative spectral indices have been detected at centimeter wavelengths in some protostellar jets, indicating the presence of a non-thermal component. Detecting non-thermal emission implies the existence of relativistic particles interacting with magnetic fields, and therefore, the action of a mechanism able to efficiently accelerate them.
UB
20/06/2019 - 00/00/0000
Primordial black holes and their manifestations in astrophysical phenomena.
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
I will discuss some new ideas regarding formation of black holes in the early universe, as well as the astrophysical implications of primordial black holes, which can make up part or all of dark matter and can contribute to the synthesis of heavy elements.
UB
19/06/2019 - 00/00/0000
Binary black hole populations with LIGO/Virgo
Seminari DAM (724, ICCUB building, UB Campus)
The LIGO and Virgo detectors have observed several gravitational waves from mergers of compact binary objects, mostly binary black holes. These discoveries have allowed starting characterizing the astrophysical population of binary black holes, e.g. the distribution of masses and spins, which carry information about their origin.
UB
19/06/2019 - 00/00/0000
Late bursts of star formation in normal elliptical galaxies
Aula 507 (Pere Pascual ICCUB building, UB Campus)
We normally think of elliptical galaxies as massive, stellar systems which are quasi-spherical, filled with old stars and hot gas and essentially quiescent objects. Successful simulations find them made at high redshift, as relatively small objects which grow at early times from gas infall and at late times from accreting satellites.
UB
17/06/2019 - 00/00/0000
Shift-symmetric orbital inflation: single field or multi-field?
Aula 507 (Pere Pascual, ICCUB building, UB Campus)
Multi-field inflation with curved field manifold attracts a lot of attention recently. From a theoretical aspect, this class of models may be more naturally realized in the UV completion of inflation. From the observational point of view, however, the current constraints on primordial non-Gaussianity and isocurvature perturbation already/marginally ruled out many of these models.
Generalitat de CatalunyaUniversitat de BarcelonaUniversitat Autònoma de BarcelonaUniversitat Politècnica de CatalunyaConsejo Superior de Investigaciones CientíficasCentres de Recerca de Catalunya