Seminars 2014
Seminario
Miércoles 17 de diciembre
Totalvariationbaseddenoising of gravitational wave
signals
Antonio Marquina
Universidad de Valencia
Abstract
In this talk we formulate total variation based
denoising algorithms to recover numericallysimulated
gravitational wave signals. We shall give a brief
introduction to the variational denoising and
compressing models to better understand the purpose of
this research work. We also introduce the fundamentals
of the theory of gravitational wave signals generated
by high energy astrophysical events and the interest to
detect these signals. We present some numerical results
for two types of waveforms, namely, "bursts" and
"chirps" for which catalogs are available.
El Seminario tendrá lugar a las 12:00 horas en la Sala
2.1.C08 (Edificio Sabatini) Universidad Carlos III
Seminario
Miércoles 25 de junio
A spectral theory of linear operators on a Gelfand
triplet and its application to dynamics of coupled
oscillators
Hayato Chiba
Kyushu University
Abstract
The Kuramoto model is a system of ordinary differential
equations for describing synchronization phenomena
defined as a coupled phase oscillators. In this talk,
an infinite dimensional Kuramoto model is considered,
and Kuramoto's conjecture on a bifurcation diagram of
the system will be proved.
A linear operator obtained from the linearization of
the Kuramoto model has the continuous spectrum on the
imaginary axis, so that the usual spectrum theory does
not determine the dynamics of the system. To handle
such continuous spectra, a new spectral theory of
linear operators based on Gelfand triplets is
developed. In particular, a generalized eigenvalue is
defined. It is proved that a generalized eigenvalue
determines the stability and bifurcation of the system.
El Seminario tendrá lugar a las 12:00 horas en la Sala
2.1.C17 (Edificio Sabatini) Universidad Carlos III
Seminario del "Grupo de Teorías de Campos y Física
Estadística" del Instituto Universitario Gregorio
Millán Barbany, Universidad Carlos III de Madrid,
Unidad Asociada al IEMCSIC
Miércoles 25 de junio
Statistical and entanglement entropy for black holes in
quantum geometry
Alejandro Pérez
Centre de Physique Théorique de Luminy  Aix Marseille
Université
Abstract
I will discuss the relationship between entanglement
(or geometric) entropy with statistical mechanical
entropy of horizon degrees of freedom when described in
the framework of isolated horizons in loop quantum
gravity. We show that, once the relevant degrees of
freedom are identified, the two notions coincide. The
key ingredient linking the two notions is the structure
of quantum geometry at Planck scale implied by loop
quantum gravity, where correlations between the inside
and outside of the black hole are mediated by
eigenstates of the horizon area operator.
El Seminario tendrá lugar a las 12:00 horas en el
C.S.I.C., Sala de Conferencias de C/Serrano 121.
Minicurso
17, 18 y 19 de febrero
An introduction to individualbased models
Vincenzo Capasso
Universidad de Milan
El curso tendrá lugar de 11:30 a 13:00 en la sala de
seminarios 2.1.D04 (Edificio Sabatini) Universidad
Carlos III
Seminario general (Cátedra de Excelencia)
Martes 4 de febrero
The Role of Geometric Randomness in the Mathematical
Modelling of Angiogenesis
Vincenzo Capasso
Universidad de Milan
Abstract
In biology and medicine we may observe a wide spectrum
of formation of patterns, usually due to
selforganization phenomena. Patterns are usually
explained in terms of a collective behavior driven by
"forces", either external and/or internal, acting upon
individuals (cells or organisms). In most of these
organization phenomena, randomness plays a major role;
here we wish to address the issue of the relevance of
randomness as a key feature for producing nontrivial
geometric patterns in biological structures. As working
examples we offer a review of a couple of important
case studies involving angiogenesis, i.e. tumordriven
angiogenesis [1], and retina angiogenesis [2]. In both
cases the reactants responsible for pattern formation
are the cells organizing as a capillary network of
vessels, and a family of underlying fields driving the
organization, such as nutrients, growth factors and
alike. The strong coupling of the kinetic parameters of
the relevant stochastic branchingandgrowth of the
capillary network, with the family of interacting
underlying fields is a major source of complexity from
a mathematical and computational point of view. Thus
our main goal is to address the mathematical problem of
reduction of the complexity of such systems by taking
advantage of its intrinsic multiscale structure; the
(stochastic) dynamics of cells will be described at
their natural scale (the microscale), while the
dynamics of the underlying fields will be described at
a larger scale (the macroscale) via deterministic
averaged concentrations, by applying suitable "laws of
large numbers" at a mesoscale. The intrinsic randomness
of the phenomena is responsible of the building up of a
realistic stochastic network of vessels.
[1] Capasso, V., Morale, D.: Stochastic Modelling
of Tumourinduced Angiogenesis. J. Math. Biol., 58,
21933 (2009)
[2] Capasso, V., Morale D., Facchetti, G.: The Role of
Stochasticity for a Model of Retinal Angiogenesis, IMA
J. Appl. Math. (2012); 19 pages;
doi:10.1093/imamat/hxs050
El Seminario tendrá lugar a las 13:00 horas en el
Salón de Grados de la Universidad Carlos III
Seminario
Jueves 9 de enero
Crossover effect in glassy systems and granular gases
Antonio Prados
Universidad de Sevilla
Abstract
The crossover or Kovacs effect is basically the
nonmonotonic relaxation of a physical quantity to its
equilibrium value, from an initial nonequilibrium
state. We investigate it in two cases (i) glassy
systems (ii) granular gases. In the former, the time
evolution of the energy passes through a maximum
because the system needs to pass through a more
disordered state to reach a typical equilibrium
configuration. Within a very simple model, we discuss
the relevance of recent linear response results for
understanding the Kovacs effect. The granular gas case
is quite different, since it is an intrinsically
outofequilibrium system due to the continuous loss of
energy in collisions. By introducing a simple energy
input mechanism, the granular gas reaches an
outofequilibrium steady state. A simple à la Kovacs
protocol is investigated, for which a crossover effect
is also displayed. Interestingly, it becomes anomalous
for large enough inelasticity: the granular temperature
(kinetic energy) shows a minimum instead of a maximum.
El Seminario tendrá lugar a las 12:00 horas en la Sala
2.1.C19 (Edificio Sabatini) Universidad Carlos III
