francesco coghi

Hannes Alfvéns väg 12, SE-106 91 Stockholm  francesco[dot]coghi[at]gmail[dot]com

I am a PostDoctoral Research Fellow at the Nordic Institute for Theoretical Physics (NORDITA). My research focuses on the development and application of methods to study fluctuations and rare events in nonequilibrium systems.


VITA

nordita research fellow

nordic institute for theoretical physics

See Research to have a look at what I work on.

October 2021 - Present

Lecturer of statistical physics

University of iceland

Lecturer of Statistical Physics (5 ECTS) for the Masters program in Theoretical Physics.

August 2023 - December 2023

Queen Mary University of London, UK

PhD in mathematical sciences

Project: Large deviation methods for the study of nonequilibrium systems: variational and spectral approaches.
Supervisor:  Dr. Rosemary J. Harris.
Viva: 14 Sep 2021, passed with no corrections. Examiners:  Dr. W. Just (QMUL) and Prof. G. A. Pavliotis (Imperial).

October 2017 - October 2021

Université Pierre et Marie Curie, Paris, FR

M2 in theoretical physics of complex systems

Part of the international master program of Physics of complex systems.

September 2016 - July 2017

Politecnico di Torino, SISSA & ICTP in Trieste, IT 

msc in physics of complex systems

Thesis: Large deviations of random walks on random graphs. Supervisors: Prof. Hugo Touchette and Dr. Luca Dall’Asta. Score: 110/110.

September 2015 - July 2017

Università degli studi di Padova, IT

BSC in physics

Thesis: Non-equilibrium statistical mechanics and large deviation theory. Supervisors: Prof. Attilio Stella and Prof. Marco Baiesi. Score: 104/110.

September 2012 - July 2015

Università degli studi di Padova, IT

BSC in biotechnology

Thesis: The diffusion differential equation and applications to the Brownian motion. Supervisor: Prof. Riccardo Colpi. Score: 110/110 cum laude.

September 2009 - July 2012

research

I am attracted by comprehending how fluctuations arise in out-of-equilibrium systems. In particular, I am interested in (i) developing methods to understand both the likelihood of these fluctuations and the physical mechanisms that generate them and (ii) in applying these methods to understand rare events of interesting physical models (from complex networks, biophysics, etc...).

I list here topics and project I like and work on.

methods to study large deviations, rare events, and fluctuation dynamics

memory driven systems

A general theory of fluctuations for systems driven by memory does not exist yet. Here, we try to develop a theory of fluctuations and large deviations of self-interacting diffusions, i.e., processes with a drift dependent on their past occupation.

beyond large deviations

Large deviation theory characterises the leading behaviour of rare events. Going beyond large deviations is a challenging mathematical question, but discrete-time Markov chains seem to offer a good 'first' understanding of subleading behaviour.

feynman-kac and mckean methods

Sampling a rare event using Monte Carlo methods is computationally prohibitive. Therefore, one often resorts to sampling from a tilted (on the rare event of interest) distribution. This can be estimated by implementing many-particle approximations of Feynman-Kac formulae. An interesting question that arises here is: what is the error made by these methods?

adaptive importance sampling

Many-particle methods are certainly useful, but for large state spaces they may also become computationally expensive when sampling rare events. A possible solution to overcome this problem is to use single particle algorithms that adapt overtime to the rare event to sample. Do we have a way to effectively compare many-particle and adaptive methods?

bounds and fluctuation theorems

Often explicit probability distributions of interesting observables may not be easy to calculate. In such cases it is at least useful to have either thermodynamic or probabilistic bounds to guide our understanding of what happens.

applications

complex networks

Rare events of stochastic processes evolving on graphs may unravel interesting topological features of the graph itself and of the interplay between the inherent randomness of the stochastic process and the randomness of the environment that embeds it.

reset processes

These are processes that have the property of being re-initialised at random times to a specific initial condition, e.g., the queue at the front-office, or the motion of a protein in a cell. The focus is again on studying their fluctuations by means of large deviation theory.


publications

13 - Generalised Landauer bound from absolute irreversibility

with Lorenzo Buffoni and Stefano Gherardini (October 2023) arXiv:2310.05449

12 - Understanding random-walk dynamical phase coexistence through waiting times

with David Stuhrmann (August 2023) arXiv:2308.03567. Accepted as a regular article in Physical Review Research.

11 - thermodynamic cost of precision for general counting observables

with Patrick Pietzonka (May 2023) arXiv:2305.15392

10 - dynamical fluctuations in a minimal model of higher-order networks

with Leonardo Di Gaetano, Giorgio Carugno, and Federico Battiston (April 2023) arXiv:2303.18169

9 - Convergence of the Integral Fluctuation Theorem estimator for nonequilibrium Markov systems

with Lorenzo Buffoni and Stefano Gherardini (November 2022) J. Stat. Mech. (2023) 063201

8 - Adaptive power method for estimating large deviations in Markov chains

with Hugo Touchette (November 2022) Phys. Rev. E 107, 034137

arXiv     PRE

7 - DELOCALISATION-LOCALISATION DYNAMICAL PHASE TRANSITION OF RANDOM WALKS ON GRAPHS

with Giorgio Carugno and Pierpaolo Vivo (June 2022) Phys. Rev. E 107, 024126

arXiv     PRE

6 - maximal dispersion of adaptive random walks

with Gabriele Di Bona, Leonardo Di Gaetano and Vito Latora (January 2022) Phys. Rev. Res. 4, L042051

arXiv    PRR

5 - Graph-combinatorial approach for markov chain large deviations

with Giorgio Carugno and Pierpaolo Vivo (January 2022) J. Phys. A: Math. Theor. 55 295001

arXiv    JPA

4 - role of current fluctuations in nonreversible samplers

with Raphael Chetrite and Hugo Touchette (March 2021) Phys. Rev. E 103, 062142

arXiv    PRE

3 - A large deviation perspective on ratio observables in reset processes: robustness of rate functions

with Rosemary J. Harris (March 2020) J. Stat. Phys 179, 131-154

arXiv    JSP

2 - large deviations of random walks on random graphs

with Jules Morand and Hugo Touchette (February 2019) Phys. Rev. E 99, 022137

arXiv    PRE

1 - controlling the uncertain response of multiplex networks

with Filippo Radicchi and Ginestra Bianconi (December 2018) Phys. Rev. E 98, 062317

arXiv    PRE

PHD thesis

large deviation methods for the study of nonequilibrium systems: variational and spectral approaches.

September 2021


visits

Stanford University, Palo Alto, (CA, US)

Visiting rotskoff group. 

Mar 13 - 22 2023

MPI PKS Dresden (DE)

Visiting the physics of complex systems division of the Max planck institute. 

Jan 11 - 15 2023

ENS Lyon (FR)

Chercheur en physique du cnrs.
working with dr. freddy bouchet on rare event algorithms. 

Sep 11 - Oct 12 2022

Applied Math, Stellenbosch (RSA)

working with prof. Hugo touchette and johan du buisson on gauge properties of large deviations.

07 Oct - 10 Dec 2021

ENS Lyon (FR)

working with Dr. freddy bouchet on rare event algorithms.

Jun 13 - 15 2021

LJAD, Nice (FR)

workinG with dr. raphael chetrite on nonreversible diffusion.

Jun 5 - 30 2021

LJAD, Nice (FR)

workinG with dr. raphael chetrite on self-interacting diffusion.

Sep 01 - 24 2020

LJAD, Nice (FR)

workinG with dr. raphael chetrite on self-interacting diffusion.

Ago 21 - Sep 26 2019

Universita di Padova (IT)

invited by prof. Marco baiesi. visiting stat. mech. group in padova.

Mar 13 - 15 2019

SISSA, Trieste (IT)

master thesis internship.

May - Jul 2017

NITheP, Stellenbosch (RSA)

master thesis internship.

Jan - Apr 2017

talks and posters

Reykjavik (IC)

maths department at university of iceland

Oct 04 2023

Las Vegas (US)

APS march meeting

Mar 05-09 2023

NORDITA, Stockholm (SE)

winq workshop

Feb 02 2023

Oxford Mathematical Institute (UK)

Networks seminar

Jan 31 2023

MPI PKS, Dresden (GE)

mpi physics of complex systems division

Jan 11 2023

University of Luxembourg (LU)

'postmodern thermodynamics' workshop

Dec 06-10 2022

Online

Meco 47 conference

Jun 13-16 2022

LJAD, Nice (FR)

'From Information and control to non-equilibrium physics' conference

Jun 06-08 2022

ENS, Paris (FR)

'Journeés de Physique Statistique' Conference

Jan 27-28 2022

ICTP, Trieste (IT)

'statistical physics of complex systems' conference

Sep 8-10 2021

Brunico (IT)

'fundamental problems in statistical physics xv' summer school

Jul 11-24 2021

Online

'joint european thermodynamics' conference

Jun 15-18 2021

Online

aps march meeting

Mar 17 2021

Imperial College London (UK)

nonequilibrium statistical mechanics group

Feb 25 2021

Stanford University (US)

department of chemistry theory group 

Feb 17 2021

Max Planck Institute, Leipzig (DE)

mathematics in the science group

Feb 03 2021

Online

summer retreat on heat, water, noise, and life at ictp

Jun 30 2020

LJAD, Nice (FR)

probability group

Sep 07 2019

Ulip, Paris (FR)

dssp workshop

Apr 01-03 2019

Open University, Milton Keynes (UK)

'open statistical physics' conference

Mar 27 2019

Universita di Padova (IT)

statistical mechanics group

Mar 14 2019

Paris (FR)

'netsci' conference

Jun 13-15 2018

Imperial College London (UK)

'siam' annual conference

Jun 11 2018

ICTP, Trieste (IT)

'nonequilibrium systems in physics, geosciences, and life sciences' workshop

May 14-25 2018

SISSA, Trieste (IT)

statistical mechanics group

May 22 2017

attendance to schools and conferences

Imperial College London (UK)

workshop on interacting particle systems and applications

Dec 09-10 2019

Beg Rohu, Quiberon (FR)

beg rohu summer school of physics. glasses, jamming, and slow dynamics.

Jun 24 - Jul 06 2019

King's College London (UK)

the third king's workshop on random graphs and random processes

Apr 09 2019

King's College London (UK)

the second king's workshop on random graphs and random processes

Apr 17 2018

ICTP, Trieste (IT)

spring school in physics of complex systems

Apr 10 - May 5 2017

teaching

At Queen Mary University of London

- (2019-20) Teaching assistant of Introduction to probability and Chaos and fractals.
- (2018-19) Teaching assistant of Calculus II and Differential equations.
- (2017-18) Teaching assistant of Calculus II and Introduction to probability.

private tutor

I have been a private tutor for Combinatorics, Graph theory, Dynamical systems, and Quantum mechanics. 

mentoring

david stuhrmann

Then, MSc student in Computational Physics at Stockholm University.
MSc Thesis on adaptive algorithms to sample rare events.

hobbies & interests