Carissimi,
la prossima giornata di seminari sara` il 14 Settembre 2018. Ricordo che ciascuno oratore fara` una lezione introduttiva e divulgativa di 45 minuti pensata proprio per i non esperti, seguita da altri 45 minuti di tipo seminario (vedi programma).
Maggiori informazioni e aggiornamenti sulle giornate passate e future sono reperibili alla pagina web che vi invitiamo a visitare periodicamente. http://web.math.unifi.it/users/fnardi/seminari/
A SUMMER DAY IN PROBABILITY AND STATISTICAL PHYSICS
University of Florence Friday 14 September 2018
Lecturers: Stefano Olla (Paris) and Raúl Rechtman (Mexico)
Location: Aula Magna di Via S. Gallo 10, Firenze
Prof. Stefano Olla (Universite` Paris Dauphine)
Title: Hyperbolic Hydrodynamic Limits
Abstract: I will present a review of old and new results (and open problems) concerning scaling limits for conservation laws in the hyperbolic space-time scale, for a system of anharmonic oscillators with external boundary tension. The macroscopic equation is given by the compressible Euler system, with corresponding boundary conditions. The problem is particularly challenging when shockwaves are present. Some results exists when the microscopic dynamics is perturbed by a conservative stochastic viscosity. Works in Collaboration with Stefano Marchesani (GSSI) and Lu Xu (CEREMADE).
Prof. Raúl Rechtman, (Universidad Nacional Autónoma de México)
Title: Chaos and damage spreading in a probabilistic cellular automaton
Abstract: Deterministic Boolean cellular automata (CA) are discrete maps F:BN → BN, B={0,1}, x(t+1)=F(x(t)) with x ϵ BN, N large and t=0,1,… . The vector x is the state of the cellular automaton with components xi,, i=0,…,N-1 the state of cell I. Each cell is connected to others, generally in a uniform and local way, and one can define an adjacency matrix aij=1 is cell j is connected to cell i and zero otherwise. The global map F is determined by the parallel application of a local function f, such that xi(t+1) = f(vi(t)), where vi denotes the state of cells connected to cell i. Deterministic CA are thus the discrete equivalent of dynamical systems, and many concepts like trajectory (the sequence of configurations x(t)), fixed points and limit cycles can be used. There are cellular automata for which a small modification in an initial configuration propagates to the whole system, a situation similar to chaos in continuous systems, and indeed one can extend the concept of the largest Lyapunov exponent to deterministic CA using Boolean derivatives. One of the main inconvenient is that these systems do not have continuous parameters to be tuned, in order to study bifurcations.
In probabilistic cellular automata, the function f (and thus F) is defined in terms of transition probabilities so that deterministic CA can be seen as the extreme cases of probabilistic ones, when the transition probabilities are either zero or one. Probabilistic CA can be seen also as Markov chains, and one can observe interesting phase transitions after changing the transition probabilities that are therefore continuous control parameters.
A realization of a specific trajectory is determined by the extraction of one or more of random numbers for each cell. By extracting these numbers at the beginning of the simulation, for all cells and all times, one converts a probabilistic CA into a deterministic one, running over a quenched random field. One can therefore use the concepts of deterministic CA, like damage spreading and maximum Lyapunov exponent also for probabilistic CA, with the advantage of having the possibility of fine-tuning the control parameters.
In particular, we investigate a probabilistic cellular automaton which can be considered an extension of a model in the universality class of directed percolation models, but with two absorbing states. In the first part of the talk all the concepts mentioned above are defined and in the second part, the probabilistic cellular automaton is studied numerically. We show that the phase transitions when the order parameter is the average damage do not coincide with those found for the Lyapunov exponent and the reason of this is the presence of absorbing states.
Program: 11.00-11.45 Introductory lecture: Olla 11.45-12.00 Break 12.00-13.00 Seminar: Olla 13.00-14.30 Lunch 14.30-15.15 Introductory lecture: Rechtman 15.15-15.30 Break 15.30-16.30 Seminar: Rechtman
Organizers: F. Caravenna, N. Cancrini, E.N.M. Cirillo, P. Dai Pra, A. De Masi, D. Fanelli, F. Flandoli C. Giardina`, R. Livi, F. Martinelli, I.G. Minelli, F.R. Nardi, E. Presutti, B. Scoppola, E. Scoppola
Note pratiche: 1) E` importante prenotare il biglietto del treno il piu` presto possibile per poter usufruire di sconti!!!! 2) Stiamo prenotando un ristorante (diverso dal precedente) con un paio di menu fissi (di cui uno vegerariano) che possa ospitarci, ma ho bisogno del numero di persone che vogliono mangiare insieme. A coloro che fossero interessati chiedo di mandare un email a francescaromana.nardi@unifi.it Resta fermo il fatto che saremo in pieno centro di Firenze, quindi ci sono moltissime altre possibilita` per mangiare se preferite regolarvi indipendentemente.
Vi aspettiamo numerosi Francesca R. Nardi
Dipartimento di Matematica e Informatica Università degli Studi di Firenze Viale Morgagni 67, Firenze, Italy
Carissimi,
ben tornati dalle vacanze!!! Vi ricordo l'appuntamento con
A SUMMER DAY IN PROBABILITY AND STATISTICAL PHYSICS
University of Florence Friday 14 September 2018
con il doppio seminario di:
Prof. Stefano Olla (Universite` Paris Dauphine)
Title: Hyperbolic Hydrodynamic Limits
Prof. Raúl Rechtman, (Universidad Nacional Autónoma de México)
Title: Chaos and damage spreading in a probabilistic cellular automaton
nel messaggio sottostante ci sono informazioni dettagliate. Per facilitare una buona organizzazione per cortesia confermate la vostra presenza!
Vi aspettiamo
Francesca R. Nardi
-------- Messaggio originale --------
OGGETTO: A Summer Day in Probability and Statistical Physics
DATA: Giovedì 16/08/2018 10:47
MITTENTE: Francesca Romana Nardi francescaromana.nardi@unifi.it
DESTINATARIO: random@fields.dm.unipi.it
Carissimi,
la prossima giornata di seminari sara` il 14 Settembre 2018. Ricordo che ciascuno oratore fara` una lezione introduttiva e divulgativa di 45 minuti pensata proprio per i non esperti, seguita da altri 45 minuti di tipo seminario (vedi programma).
Maggiori informazioni e aggiornamenti sulle giornate passate e future sono reperibili alla pagina web che vi invitiamo a visitare periodicamente. http://web.math.unifi.it/users/fnardi/seminari/
A SUMMER DAY IN PROBABILITY AND STATISTICAL PHYSICS
University of Florence Friday 14 September 2018
Lecturers: Stefano Olla (Paris) and Raúl Rechtman (Mexico)
Location: Aula Magna di Via S. Gallo 10, Firenze
Prof. Stefano Olla (Universite` Paris Dauphine)
Title: Hyperbolic Hydrodynamic Limits
Abstract: I will present a review of old and new results (and open problems) concerning scaling limits for conservation laws in the hyperbolic space-time scale, for a system of anharmonic oscillators with external boundary tension. The macroscopic equation is given by the compressible Euler system, with corresponding boundary conditions. The problem is particularly challenging when shockwaves are present. Some results exists when the microscopic dynamics is perturbed by a conservative stochastic viscosity. Works in Collaboration with Stefano Marchesani (GSSI) and Lu Xu (CEREMADE).
Prof. Raúl Rechtman, (Universidad Nacional Autónoma de México)
Title: Chaos and damage spreading in a probabilistic cellular automaton
Abstract: Deterministic Boolean cellular automata (CA) are discrete maps F:BN → BN, B={0,1}, x(t+1)=F(x(t)) with x ϵ BN, N large and t=0,1,… . The vector x is the state of the cellular automaton with components xi,, i=0,…,N-1 the state of cell I. Each cell is connected to others, generally in a uniform and local way, and one can define an adjacency matrix aij=1 is cell j is connected to cell i and zero otherwise. The global map F is determined by the parallel application of a local function f, such that xi(t+1) = f(vi(t)), where vi denotes the state of cells connected to cell i. Deterministic CA are thus the discrete equivalent of dynamical systems, and many concepts like trajectory (the sequence of configurations x(t)), fixed points and limit cycles can be used. There are cellular automata for which a small modification in an initial configuration propagates to the whole system, a situation similar to chaos in continuous systems, and indeed one can extend the concept of the largest Lyapunov exponent to deterministic CA using Boolean derivatives. One of the main inconvenient is that these systems do not have continuous parameters to be tuned, in order to study bifurcations.
In probabilistic cellular automata, the function f (and thus F) is defined in terms of transition probabilities so that deterministic CA can be seen as the extreme cases of probabilistic ones, when the transition probabilities are either zero or one. Probabilistic CA can be seen also as Markov chains, and one can observe interesting phase transitions after changing the transition probabilities that are therefore continuous control parameters.
A realization of a specific trajectory is determined by the extraction of one or more of random numbers for each cell. By extracting these numbers at the beginning of the simulation, for all cells and all times, one converts a probabilistic CA into a deterministic one, running over a quenched random field. One can therefore use the concepts of deterministic CA, like damage spreading and maximum Lyapunov exponent also for probabilistic CA, with the advantage of having the possibility of fine-tuning the control parameters.
In particular, we investigate a probabilistic cellular automaton which can be considered an extension of a model in the universality class of directed percolation models, but with two absorbing states. In the first part of the talk all the concepts mentioned above are defined and in the second part, the probabilistic cellular automaton is studied numerically. We show that the phase transitions when the order parameter is the average damage do not coincide with those found for the Lyapunov exponent and the reason of this is the presence of absorbing states.
Program: 11.00-11.45 Introductory lecture: Olla 11.45-12.00 Break 12.00-13.00 Seminar: Olla 13.00-14.30 Lunch 14.30-15.15 Introductory lecture: Rechtman 15.15-15.30 Break 15.30-16.30 Seminar: Rechtman
Organizers: F. Caravenna, N. Cancrini, E.N.M. Cirillo, P. Dai Pra, A. De Masi, D. Fanelli, F. Flandoli C. Giardina`, R. Livi, F. Martinelli, I.G. Minelli, F.R. Nardi, E. Presutti, B. Scoppola, E. Scoppola
Note pratiche: 1) E` importante prenotare il biglietto del treno il piu` presto possibile per poter usufruire di sconti!!!! 2) Stiamo prenotando un ristorante (diverso dal precedente) con un paio di menu fissi (di cui uno vegerariano) che possa ospitarci, ma ho bisogno del numero di persone che vogliono mangiare insieme. A coloro che fossero interessati chiedo di mandare un email a francescaromana.nardi@unifi.it Resta fermo il fatto che saremo in pieno centro di Firenze, quindi ci sono moltissime altre possibilita` per mangiare se preferite regolarvi indipendentemente.
Vi aspettiamo numerosi Francesca R. Nardi
Dipartimento di Matematica e Informatica Università degli Studi di Firenze Viale Morgagni 67, Firenze, Italy
AN AUTUMN DAY IN PROBABILITY AND STATISTICAL PHYSICS
University of Florence FRIDAY 23 NOVEMBER 2018
Lecturers: Giovanni Jona Lasinio (Roma) and Giambattista Giacomin (Paris)
LOCATION: AULA TRICERRI VIALE MORGAGNI 67, FIRENZE
PROF. GIOVANNI JONA LASINIO (Universita` di Roma La Sapienza)
TITLE: SINGULAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS
ABSTRACT: Singular stochastic partial differential equations (SSPDE) first appeared in rather special contexts like the stochastic quantization of field theories or in the problem of crystal growth, the well known KPZ equation. In the last decade these equations have been intensely studied giving rise to an important branch of mathematics possibly relevant for physics. This talk will review some aspects and open problems in the subject.
PROF. GIAMBATTISTA GIACOMIN (Université Paris Diderot)
TITLE: Infinite disorder renormalization fixed point: the big picture and one specific result.
ABSTRACT: the natural question of the effect of a random environment («disorder») on phase transitions and critical phenomena has attracted a lot of attention. I will give an introduction to this domain of research via an overview of some of the physical predictions and of the mathematical approaches and challenges. I will in particular develop the notion of disorder relevance and irrelevance. The focus will be on a very basic class of statistical mechanics model - called pinning models - for which in the last years the mathematical work matched the physical counterpart and, in some cases, went beyond. Nevertheless, also for pinning models the results in the regime in which disorder is relevant are rather weak and many of the physical predictions do not appear to be solid or coherent. But the situation has evolved very recently and a certain consensus has grown in favor of a very strong smoothing effect of the disorder for this class of models when disorder is relevant. This is part of a very intriguing and challenging general physical picture. The aim of the second part of the seminar is to present a very specific pinning model in which we have been able to pinpoint this strong smoothing effect (work in collaboration with Quentin Berger and Hubert Lacoin, arXiv:1712.02261). I hope I will be able to explain why we could tackle this case (and not other ones) and to develop (or sketch) at least one of the main technical ideas that are at the center of our approach.
Program: 11.00-11.45 Introductory lecture: Jona Lasinio 11.45-12.00 Break 12.00-13.00 Seminar: JonaLasinio 13.00-14.30 Lunch 14.30-15.15 Introductory lecture: Giacomin 15.15-15.30 Break 15.30-16.30 Seminar: Giacomin
Organizers: F. Caravenna, N. Cancrini, E.N.M. Cirillo, P. Dai Pra, A. De Masi, D. Fanelli, F. Flandoli C. Giardina`, R. Livi, F. Martinelli, I.G. Minelli, F.R. Nardi, E. Presutti, B. Scoppola, E. Scoppola
Ricordo che ciascuno oratore fara` una lezione introduttiva e divulgativa di 45 minuti pensata proprio per i non esperti, seguita da altri 45 minuti di tipo seminario (vedi programma).
Maggiori informazioni e aggiornamenti sono reperibili alla pagina web
http://web.math.unifi.it/users/fnardi/seminari/
Note pratiche: 1) E` importante prenotare il biglietto del treno il piu` presto possibile per poter usufruire di sconti!!!! 2) Stiamo prenotando un ristorante (diverso dal precedente) con un paio di menu fissi (di cui uno vegerariano) che possa ospitarci, ma ho bisogno del numero di persone che vogliono mangiare insieme. A coloro che fossero interessati chiedo di mandare un email a francescaromana.nardi@unifi.it Resta fermo il fatto che saremo in pieno centro di Firenze, quindi ci sono moltissime altre possibilita` per mangiare se preferite regolarvi indipendentemente.
Vi aspettiamo numerosi Francesca R. Nardi
Dipartimento di Matematica e Informatica Università degli Studi di Firenze Viale Morgagni 67, Firenze, Italy
Carissimi,
mi sono stati richiesti chiarimenti sul luogo del seminario, quindi rimando l'annuncio con link alla pagina che spiega come si arriva a all'edificio.
AN AUTUMN DAY IN PROBABILITY AND STATISTICAL PHYSICS
University of Florence FRIDAY 23 NOVEMBER 2018
Lecturers: Giovanni Jona Lasinio (Roma) and Giambattista Giacomin (Paris)
LOCATION: AULA TRICERRI VIALE MORGAGNI 67, FIRENZE
The following webpage explains how to get to the location using the new tram.
https://www.dimai.unifi.it/vp-285-come-arrivare-how-to-get.html
PROF. GIOVANNI JONA LASINIO (Universita` di Roma La Sapienza)
TITLE: SINGULAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS
ABSTRACT: Singular stochastic partial differential equations (SSPDE) first appeared in rather special contexts like the stochastic quantization of field theories or in the problem of crystal growth, the well known KPZ equation. In the last decade these equations have been intensely studied giving rise to an important branch of mathematics possibly relevant for physics. This talk will review some aspects and open problems in the subject.
PROF. GIAMBATTISTA GIACOMIN (Université Paris Diderot)
TITLE: Infinite disorder renormalization fixed point: the big picture and one specific result.
ABSTRACT: the natural question of the effect of a random environment («disorder») on phase transitions and critical phenomena has attracted a lot of attention. I will give an introduction to this domain of research via an overview of some of the physical predictions and of the mathematical approaches and challenges. I will in particular develop the notion of disorder relevance and irrelevance. The focus will be on a very basic class of statistical mechanics model - called pinning models - for which in the last years the mathematical work matched the physical counterpart and, in some cases, went beyond. Nevertheless, also for pinning models the results in the regime in which disorder is relevant are rather weak and many of the physical predictions do not appear to be solid or coherent. But the situation has evolved very recently and a certain consensus has grown in favor of a very strong smoothing effect of the disorder for this class of models when disorder is relevant. This is part of a very intriguing and challenging general physical picture. The aim of the second part of the seminar is to present a very specific pinning model in which we have been able to pinpoint this strong smoothing effect (work in collaboration with Quentin Berger and Hubert Lacoin, arXiv:1712.02261). I hope I will be able to explain why we could tackle this case (and not other ones) and to develop (or sketch) at least one of the main technical ideas that are at the center of our approach.
Program: 11.00-11.45 Introductory lecture: Jona Lasinio 11.45-12.00 Break 12.00-13.00 Seminar: JonaLasinio 13.00-14.30 Lunch 14.30-15.15 Introductory lecture: Giacomin 15.15-15.30 Break 15.30-16.30 Seminar: Giacomin
Organizers: F. Caravenna, N. Cancrini, E.N.M. Cirillo, P. Dai Pra, A. De Masi, D. Fanelli, F. Flandoli C. Giardina`, R. Livi, F. Martinelli, I.G. Minelli, F.R. Nardi, E. Presutti, B. Scoppola, E. Scoppola
Ricordo che ciascuno oratore fara` una lezione introduttiva e divulgativa di 45 minuti pensata proprio per i non esperti, seguita da altri 45 minuti di tipo seminario (vedi programma).
Maggiori informazioni e aggiornamenti sono reperibili alla pagina web
http://web.math.unifi.it/users/fnardi/seminari/
Note pratiche: 1) E` importante prenotare il biglietto del treno il piu` presto possibile per poter usufruire di sconti!!!! 2) Stiamo prenotando un ristorante (diverso dal precedente) con un paio di menu fissi (di cui uno vegerariano) che possa ospitarci, ma ho bisogno del numero di persone che vogliono mangiare insieme. A coloro che fossero interessati chiedo di mandare un email a francescaromana.nardi@unifi.it e angela.caporicci@unifi.it Resta fermo il fatto che ci sono alternative per mangiare se preferite regolarvi indipendentemente.
Vi aspettiamo numerosi Francesca R. Nardi
Dipartimento di Matematica e Informatica Università degli Studi di Firenze Viale Morgagni 67, Firenze, Italy
Carissimi,
ricordo del seminario di venerdi` prossimo 23 NOVEMBRE 2018 (ANNUNCIO SOTTOSTANTE).
Per una migliore organizzazione delle pause e dell'aula e` utile avere il numero
approssimativo dei partecipanti, quindi chiederei a chi interessato di inviare e-mail a
francescaromana.nardi@unifi.it e angela.caporicci@unifi.it
specificando se la partecipazione e` alla giornata solamente o anche al pranzo.
AN AUTUMN DAY IN PROBABILITY AND STATISTICAL PHYSICS
University of Florence FRIDAY 23 NOVEMBER 2018
Lecturers: Giovanni Jona Lasinio (Roma) and Giambattista Giacomin (Paris)
LOCATION: AULA TRICERRI VIALE MORGAGNI 67, FIRENZE
The following webpage explains how to get to the location using the new tram.
https://www.dimai.unifi.it/vp-285-come-arrivare-how-to-get.html
PROF. GIOVANNI JONA LASINIO (Universita` di Roma La Sapienza)
TITLE: SINGULAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS
ABSTRACT: Singular stochastic partial differential equations (SSPDE) first appeared in rather special contexts like the stochastic quantization of field theories or in the problem of crystal growth, the well known KPZ equation. In the last decade these equations have been intensely studied giving rise to an important branch of mathematics possibly relevant for physics. This talk will review some aspects and open problems in the subject.
PROF. GIAMBATTISTA GIACOMIN (Université Paris Diderot)
TITLE: Infinite disorder renormalization fixed point: the big picture and one specific result.
ABSTRACT: the natural question of the effect of a random environment («disorder») on phase transitions and critical phenomena has attracted a lot of attention. I will give an introduction to this domain of research via an overview of some of the physical predictions and of the mathematical approaches and challenges. I will in particular develop the notion of disorder relevance and irrelevance. The focus will be on a very basic class of statistical mechanics model - called pinning models - for which in the last years the mathematical work matched the physical counterpart and, in some cases, went beyond. Nevertheless, also for pinning models the results in the regime in which disorder is relevant are rather weak and many of the physical predictions do not appear to be solid or coherent. But the situation has evolved very recently and a certain consensus has grown in favor of a very strong smoothing effect of the disorder for this class of models when disorder is relevant. This is part of a very intriguing and challenging general physical picture. The aim of the second part of the seminar is to present a very specific pinning model in which we have been able to pinpoint this strong smoothing effect (work in collaboration with Quentin Berger and Hubert Lacoin, arXiv:1712.02261). I hope I will be able to explain why we could tackle this case (and not other ones) and to develop (or sketch) at least one of the main technical ideas that are at the center of our approach.
Program: 11.00-11.45 Introductory lecture: Jona Lasinio 11.45-12.00 Break 12.00-13.00 Seminar: JonaLasinio 13.00-14.30 Lunch 14.30-15.15 Introductory lecture: Giacomin 15.15-15.30 Break 15.30-16.30 Seminar: Giacomin
Organizers: F. Caravenna, N. Cancrini, E.N.M. Cirillo, P. Dai Pra, A. De Masi, D. Fanelli, F. Flandoli C. Giardina`, R. Livi, F. Martinelli, I.G. Minelli, F.R. Nardi, E. Presutti, B. Scoppola, E. Scoppola
Ricordo che ciascuno oratore fara` una lezione introduttiva e divulgativa di 45 minuti pensata proprio per i non esperti, seguita da altri 45 minuti di tipo seminario (vedi programma).
Maggiori informazioni e aggiornamenti sono reperibili alla pagina web
http://web.math.unifi.it/users/fnardi/seminari/
Note pratiche: 1) E` importante prenotare il biglietto del treno il piu` presto possibile per poter usufruire di sconti!!!! 2) Stiamo prenotando un ristorante (diverso dal precedente) con un paio di menu fissi
(di cui uno vegerariano) che possa ospitarci, ma ho bisogno del numero di persone che
vogliono mangiare insieme. A coloro che fossero interessati chiedo di mandare un email
a francescaromana.nardi@unifi.it e angela.caporicci@unifi.it Resta fermo il fatto che ci sono alternative per mangiare se preferite regolarvi indipendentemente.
Vi aspettiamo numerosi Francesca R. Nardi
Dipartimento di Matematica e Informatica Università degli Studi di Firenze Viale Morgagni 67, Firenze, Italy
-
Francesca Romana Nardi