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"SINEQ Final Conference"
Date:20-24 October.
All the information can be found at the web page:
https://sites.google.com/view/sineq-finalconference/home/
Abstract
Abstract
The conference focuses on recent progress in the study of stochastic dynamics, including contributions from a theoretical perspective as well as the mathematical analysis of numerical methods for the efficient simulation of these dynamics, with particular emphasis on their linear response properties.
Please check the program here
https://sites.google.com/view/sineq-finalconference/home/
We would be grateful if you could circulate it among potentially interested students and researchers.
We are looking forward to seeing you during the week.
(Università di Roma Tor Vergata)
(Università di Roma Tor Vergata)
"Constructing a weakly-interacting fixed point of the Fermionic Polchinski equation "
Date: October 27th (Monday) at 2.30 pm.
on site: at the GSSI Main Lecture Hall
zoom: https://gssi-it.zoom.us/j/87571297606pwd=uaKzpEsOHBPbP9D2XxbNsbnYGoBbsk.1
Meeting ID: 875 7129 7606
Passcode: SMAQ2526
Abstract
Abstract
The renormalization group is one of the most important tools for the description of critical points in theoretical physics. Most mathematically rigorous treatments are based on implementing the renormalization group as a discrete dynamical system, which introduces a number of theoretical complications, and in particular obscures the emergence of full scale invariance, which is one of the most important features of a critical point. In the last few years, however, there have been several new results about solutions of the Polchinski equation (a nonlinear differential equation which implements the renormalization group as a continuous dynamical system) for Fermionic systems. I will present one in particular, the construction of a nontrivial fixed point of a family of continuous renormalization group flows corresponding to certain weakly interacting Fermionic quantum field theories with a parameter in the propagator allowing the scaling dimension to be tuned in a manner analogous to dimensional regularization.
"Anomalous Regularization in Kazantsev-Kraichnan Model "
Date: November 10th (Monday) at 2.30 pm.
on site: at the GSSI Main Lecture Hall ( viale crispi 7)
zoom: https://gssi-it.zoom.us/j/87571297606pwd=uaKzpEsOHBPbP9D2XxbNsbnYGoBbsk.1
Meeting ID: 875 7129 7606
Passcode: SMAQ2526
Abstract
Abstract
We investigate a passive vector field which is transported and stretched by a divergence-free Gaussian velocity field, delta-correlated in time and poorly correlated in space (spatially nonsmooth). Although the advection of a scalar field (Kraichnan's passive scalar model) is known to enjoy regularizing properties, the potentially competing stretching term in vector advection may induce singularity formation. We establish that the regularization effect is actually retained in certain regimes. While this is true in any dimension $d\ge 3$, it notably implies a regularization result for linearized 3D Euler equations with stochastic modeling of turbulent velocities, and for the induction equation in magnetohydrodynamic turbulence.
The presentation is based on a joint work with Francesco Grotto and Mario Maurelli.
We are pleased to announce that during the week of November 24th to 28th, we will have a series of colloquia for the PhD in Mathematics and Modeling at the University of L'Aquila, according to the following schedule
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Monday November 24; 16.30--17.30; Aula Seminari Turing building
Speaker: Carlangelo Liverani (University of Roma 2)
Title: Divination is hard, but on average …
Abstract: will discuss the phenomenon of instability with respect to initial conditions and attempt to explain why, in certain cases, probabilistic ideas can be helpful.
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Tuesady November 25; 16.30--17.30; room A1.2 Turing building
Speaker: Claudio Landim (IMPA, Rio de Janeiro)
Title: Metastability of Markov processes
Abstract: Metastability is a physical phenomenon ubiquitous in first order phase
transitions. A tentative of a precise description can be traced back,
at least, to Maxwell at the end of the XIX century.
In the mid-1980s, Cassandro, Galves, Olivieri and Vares,
in the sequel of Lebowitz and Penrose, proposed a first
rigorous method for deducing the metastable behavior of Markov
processes, based on the theory of large deviations developed by
Freidlin and Wentsel. This method, known as the
pathwise approach to metastability, was successfully applied to
many models in statistical mechanics.
In the following years, different approaches were put forward. In this talk
we review some recent results in this field. In particular, we show that
the metastable behavior of a sequence of
Markov chains can be read from a property of the solutions of the
resolvent equation associated with the generator of the process. It
turns out that this property is not only sufficient, but also
necessary for metastability.
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Wednesday November 26; 16.30--17.30; Aula Seminari Turing building
Speaker: Pedro L. Garrido (Universidad de Granada)
Title: NONEQUILIBRIUM STATISTICAL MECHANICS: A PERSONAL OVERVIEW
Abstract: Nonequilibrium statistical mechanics deals with interacting $N$-particle systems subjected to external agents that generate currents within the system.
We are interested in the stationary states reached by such systems after their long-time evolution from an initial configuration. We will introduce some basic concepts and focus on recent studies to present theoretical and numerical strategies that help characterize their behavior.
In particular, we will discuss the classical anharmonic chain under the action of an external periodic forcing, how to obtain the stationary distribution by solving a Hamilton–Jacobi equation, and the importance of numerical experiments for gaining precise insight into these complex systems.
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Everyone is welcome
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