https://www.edpif.org/phorum/index.php Sun, 05 Apr 2026 20:03:44 +0200 Phorum 5.2.23 https://www.edpif.org/phorum/read.php?3,450,450#msg-450 https://www.edpif.org/phorum/read.php?3,450,450#msg-450 %%%%%%%%%%%% French Version (english version below) %%%%%%%%%%%%%%
Cinématique des écoulements en milieux poreux 3D

L'unité de recherche RECOVER de l'INRAE ​​(Aix-en-Provence, France) invite les candidats talentueux et motivés à candidater pour une thèse de doctorat (3 ans) consacrée à la caractérisation expérimentale de la cinématique des écoulements en milieux poreux 3D, afin d'étudier l'influence des hétérogénéités locales sur les processus de transport.

Cette thèse est financée par le département AQUA de l'INRAE ​​et devrait débuter en octobre 2026 (dates flexibles). Le/la candidat(e) retenu(e) sera encadré(e) par Mathieu SOUZY et Pierre PHILIPPE. Plus d'informations sont disponibles ici : https://nextcloud.inrae.fr/s/HzLejSaygyHdXqe

Mots-clés : milieux poreux 3D, expérimental, techniques de visualisation directe, processus de transport, cinématique des écoulements, échelle du pore

Nous attendons avec intérêt les candidatures motivées !

%%%%%%%%%%%% English Version %%%%%%%%%%%%%%
Flow kinematic in 3D porous media

The research unit RECOVER from INRAE (Aix-en-Provence, France) is pleased to invite applications of talented and motivated candidates for a PhD (3 years) dedicated to the experimental characterization of the flow kinematic within 3D porous media, to uncover the effect of local heterogeneities on transport processes.

The PhD is funded by the Department AQUA from INRAE, and is expected to start in October 2026 (with some flexibility), and the successful candidate will be supervised by Mathieu SOUZY and Pierre PHILIPPE. More informations are available here: https://nextcloud.inrae.fr/s/HzLejSaygyHdXqe
Keywords: 3D porous media, experiments, direct visualization techniques, transport process, flow kinematic, pore scale

We are looking forward to receive motivated applications!


Cordialement,
Mathieu Souzy]]> Msouzy Thèses hors de l'EDPIF Wed, 18 Mar 2026 14:15:59 +0100 https://www.edpif.org/phorum/read.php?3,449,449#msg-449 https://www.edpif.org/phorum/read.php?3,449,449#msg-449 Supervisor: J. Unterberger
Host Institution: Institut Élie Cartan de Lorraine (IECL), Université de Lorraine, Nancy, France
________________________________________

Scientific Context Large chemical reaction networks (CRNs), involving hundreds of interacting species, arise naturally in prebiotic chemistry, systems chemistry, and astrochemistry. Since the 1952 Miller–Urey experiment demonstrated the abiotic synthesis of complex organic molecules, understanding the dynamical organization of such networks has remained a major scientific challenge.
These systems are characterized by: high dimensionality; strong separation of kinetic scales; poorly known reaction parameters; and sensitivity to stochastic effects.
While the general mathematical theory of CRNs is well established [1], scalable and interpretable methods for large multiscale systems are still lacking.

Project Overview This project builds on a novel multiscale reduction method, currently developed for linear CRNs [2], based on an explicit separation of time scales, and producing:
• coarse-grained, renormalized formulas based on hierarchical graphs;
• a fast and accurate strategy for statistical inference of effective kinetic parameters.
The method yields a low-complexity, interpretable algorithm (implemented in Python) capable of accurately predicting dominant dynamical regimes.
The PhD project aims to extend this framework:
1. to nonlinear reaction networks, using linearization around stationary states, multiscale perturbation methods and tropical geometry techniques;
2. to stochastic dynamics, incorporating noise-induced transitions and multistationarity into the hierarchical description.

References. [1] M. Feinberg, Foundations of Chemical Reaction Network Theory. Applied Math. Sciences, Springer (2019). [2] P. Nghe, J. Unterberger. Stoechiometric and dynamical autocatalysis for diluted chemical reaction networks, J. Math. Biol. (2022). J. Unterberger, General multi-scale estimates for Lyapunov data of Perron-Frobenius matrices. The case of diluted autocatalytic chemical reaction networks, arXiv:2511.11073. J. Unterberger, U. Herbach, R. Cellier. Hierarchical models for large chemical reaction networks (preprint).

Expected Outcomes
• A multiscale mathematical framework for large nonlinear CRNs
• A stochastic extension describing noise-driven dynamics
• A user-friendly computational tool for chemists
• Applications to experimentally relevant reaction systems
The resulting software will help identify dominant pathways, predict time evolution under varying conditions, and infer effective kinetic parameters from experimental data.

Candidate Profile We seek a highly motivated candidate with a strong background in mathematics or theoretical physics, interest in dynamical systems or statistical physics, and solid Python programming skills.

Research Environment The project will be carried out at IECL, in tight collaboration with mathematicians, statisticians, theoretical physicists, and experimental chemists in Nancy and nearby Paris area (ESPCI, Ecole Supérieure de Physique et Chimie Industrielle; Saclay, BioCIS Lab for biomolecules), who are partners of the supervisor in a wider research project on the origin of life. The candidate will also benefit from interactions in Nancy with the probability and statistics team at IECL, and the computational biology and chemistry team at the LPCT lab.

Contact jeremie.unterberger@univ-lorraine.fr, website: [jeremieunterberger.wixsite.com]]]> Jeremie Unterberger Thèses hors de l'EDPIF Mon, 16 Feb 2026 17:56:17 +0100 https://www.edpif.org/phorum/read.php?3,448,448#msg-448 https://www.edpif.org/phorum/read.php?3,448,448#msg-448
I am recruiting a PhD student to work with me in the Physics Department at King’s College London, starting in October 2026.

The project lies at the interface of computational physics and cell biology, and focuses on non-equilibrium and collective phenomena at the cell surface. Based in the heart of London, the student will join a vibrant, international community of bio- and soft-matter physicists, and will work in regular contact with experimental collaborators. The application deadline is February 28th. Interested students are welcome to contact me via email before applying.

Further details about the project and the application procedure can be found at the following link:
[www.findaphd.com]

Please forward this message to any students who may be interested.

Best regards,

Ivan

—
Ivan Palaia
Lecturer (Assistant Professor)
King’s College London
ipalaia.wordpress.com]]> ivan.palaia@kcl.ac.uk Thèses hors de l'EDPIF Sun, 25 Jan 2026 22:20:41 +0100 https://www.edpif.org/phorum/read.php?3,447,447#msg-447 https://www.edpif.org/phorum/read.php?3,447,447#msg-447 physics to join the research group of Johannes Hofmann at the University of Gothenburg
in Sweden. The Department of Physics at the University of Gothenburg is located in the
centre of Gothenburg on the west coast of Sweden and has approximately 120 employees.
Together with Chalmers University located on the same campus, we form the Gothenburg
Physics Centre, which is one of the largest places for physics research in the Nordic
countries.

The PhD project aims to develop advanced statistical methods based on kinetic theory,
utilising both numerical and analytical approaches, to study charge and heat transport in
electron and electron-phonon gases. The project will focus on hydrodynamic transport–a
recently observed mode of transport driven by dominant interactions–in both solid-state
systems and atomic quantum gases. The admitted doctoral student will be part of a small,
active theory group with close supervision and international collaborations.

We are looking for highly motivated individuals with experience and interest in analytical
and numerical calculations in condensed-matter physics, statistical physics, or atomic
physics. Previous research experience in many-body physics or quantum theory would be
helpful but is not required.

A PhD position in Sweden is a four-year full-time programme that leads to a doctoral
degree. The position is fully funded for the entire duration, with a current monthly starting
salary of 34800 SEK. Doctoral students must primarily devote themselves to research but
may to a limited extent engage in teaching and outreach activities. Such work may, before
the doctoral degree is completed, not cover more than 20% of full-time work, which
typically extends the total duration of the position to five years.

For further details and the application link, please visit the position webpage:

[web103.reachmee.com]
d79bb7258ad55c8d75228e5b7&job_id=39304

Candidates are welcome to contact Johannes Hofmann for further enquiries.]]> felix_werner Thèses hors de l'EDPIF Sun, 25 Jan 2026 22:09:11 +0100 https://www.edpif.org/phorum/read.php?3,446,446#msg-446 https://www.edpif.org/phorum/read.php?3,446,446#msg-446 Marangoni propulsion and interaction with flows

The presence of surfactant such as amphiphilic molecules at the air-water interface may locally alter
the surface tension and induce a flow in the underlying water, as exemplified in the celebrated tears of wine
phenomenon. Such Marangoni effects have a long history - with early observation dating back to 1557- but
their study has received a new impetus with the current interest in active matter. Indeed, they can be
exploited to design “Marangoni swimmers”: macroscopic particles without moving parts that spontaneously
self-propel at the surface of water. Such swimmers have been developed in our team [1] where
their behavior was shown to motivate a host of questions, from their individual propulsion to striking
collective properties such as active turbulence [2].

Having recently characterized the propulsion mechanism at an individual scale and in the presence
of a simple external flow, the goal is now to study the interactions between two swimmers. To do so, we
will leverage the techniques we have developed for characterizing both the flows and forces, using PIV
(Particle Image Velocimetry) and a cantilever force sensor. We will examine the forces and flows that develop around a pair of swimmers. We will also investigate the interactions of a swimmers with a wall.

In the long term, we will seek to understand how the transport of an interfacial swimmer is affected
by a complex external flow. By placing a swimmer in a vortex network, we will study, both experimentally
and numerically, the interaction between the swimmer and the flow on the scale of a vortex. This study will
also unveil the resulting large-scale transport properties of the swimmer, a complex situation that involves
many couplings.

The student will combine experimental investigation with exploration of simplified models to develop a clear physical understanding. This topic lies at the confluence of soft matter, fluid mechanics and statistical physics.

Opening toward a PhD: yes (funding with «bourse ministère»).

Contact:
Cécile Cottin-Bizonne (cecile.cottin-bizonne@univ-lyon1.fr)
François Detcheverry (francois.detcheverry@univ-lyon1.fr)
Christophe Ybert (christophe.ybert@univ-lyon1.fr)

Team Liquides et Interfaces, Institut Lumière Matière, Lyon

See full offer here [choose "save link/ target as"]

References
[1] Self-propulsion of symmetric chemically active particles: Point-source model and experiments on camphor disks
Boniface, Cottin-Bizonne, Kervil, Ybert and Detcheverry, Physical Review E (2019).
[2] Kolmogorovian active turbulence of a sparse assembly of interacting Marangoni surfers,
Bourgoin, Kervil, Cottin-Bizonne, Raynal, Volk and Ybert, Physical Review X (2019).]]> François Detcheverry Thèses hors de l'EDPIF Fri, 14 Nov 2025 17:35:09 +0100 https://www.edpif.org/phorum/read.php?3,445,445#msg-445 https://www.edpif.org/phorum/read.php?3,445,445#msg-445
Transport and extreme statistics for bacterial ecology,
a controlled system: magnetotactic bacteria in porous media

Supervisors: Nicolas Waisbord & Jean-François Rupprecht, Marseille Luminy (France)

Pitch: Magnetotactic bacteria (MTB) navigate along Earth’s magnetic field. We hypothesize that magnetic alignment modulates dispersion in sediments, thereby promoting MTB biodiversity in heterogeneous environments. We will recast microbial colonization as a problem in extreme-value statistical physics: the key quantity is not the mean, but the arrival of the first bacterium that seeds a colony. Experimentally, we will quantify transport and rare-event statistics by combining microfluidic sediment analogs, optical tracking, and magnetically controlled flow/field conditions, supported by a complete microfluidic platform (microfabrication and microscopy). Theoretically, we have developed a simulation pipeline. Together, these approaches will link heterogeneities in pores, flows, and bacterial traits to population-level dispersion and segregation.

Keywords: active matter, transport in porous media, magnetotactic bacteria, microfluidics, natural sediments, first-passage time, microbial ecology, niche partitioning.

_____________

Context:
Magnetotactic bacteria (MTB) are microorganisms capable of orienting themselves along Earth's magnetic field lines thanks to chains of magnetic nanocrystals within their membranes. These bacteria have been studied for 60 years in soluble media, while they essentially live in a highly localized manner, confined to the first millimeters of aquatic sediments. What has limited the study of these bacteria under real conditions is that sediments are porous, opaque, and dense media that are difficult to access. We have developed several microfluidic systems that allow mimicking the physics of flows in artificial sediment under a microscope. Our recent work on MTBs in model porous media reveals rich, non-linear physics, with vortical trapping phenomena, heavy-tailed passage time distributions, and "bacterial diode" regimes where flow can be completely blocked under certain conditions – where the applied magnetic field plays the role of a control parameter for these non-linearities.
PhD project ambition: This work aims to answer a major question in the field: what is the evolutionary advantage of magnetotaxis in these disordered confined environments? Recent work suggests that at the individual scale, the magnetic field helps bacteria navigate well. In this thesis, we will test a complementary and competitive hypothesis, according to which the magnetic field also controls niche selection within sediments and thus increases MTB biodiversity in these heterogeneous environments.

Method:
We propose to model the microbiological colonization of sediments as a problem of extreme statistical physics, where the magnetic field controls the finer scales of niche partitioning. Until now, approaches have focused on averaged properties of porous media. However, in the context of microbial ecology, what is critical is the question of the first bacterium, the one that will generate a new colony. It is therefore this complex transport and extreme statistics that will interest us for MTBs in sediments. This statistic will be strongly correlated with the statistics of pore and flow heterogeneities, but also with bacterial sensitivity to the magnetic field.

M2 internship research project:
In this internship, we will focus on transport and seek to quantify and model bacterial flux through, first (step 1) a transparent model porous medium, then (step 2) through a real sediment. We will center our study on first passage time (FPT) statistics. We will compare the sensitivity of FPT statistics to the magnetic field through a real, opaque sediment, and a transparent micromodel where trajectories can be reconstructed to allow us to establish a realistic test model system for porous media from the transport perspective. The methodology is structured around:
(i) designing microfluidic devices with controlled geometries to establish reference measurements of FPT distributions as a function of magnetic field and flow conditions;
(ii) integrating real sediment samples from MTB-rich sites into these devices to perform direct measurements through natural porous structures;
(iii) modelling the detailed statistical analysis of these distributions, with particular attention to heavy tails and non-ergodic behaviors.
The comparison between transparent model geometries (where trajectories can be reconstructed) and opaque real sediments (where only FPTs are accessible) will identify which structural properties of these sediments effectively control their exploration by MTBs.
Skills to be developed: Microfluidics, microscopy, image processing and trajectory analysis, stochastic modeling (CTRW, Langevin), environmental sample handling.

Desired skills:
The ideal candidate is a physicist who enjoys understanding fundamental mechanisms (here: transport in porous media) but is ready to gradually open up to broader biological and ecological questions. Taste for experimentation (from tinkering to fine manipulation). Solid background in statistical physics and stochastic processes. Capabilities in data processing and image analysis (Python, Matlab, or equivalent). Autonomy, scientific curiosity and open-mindedness: the project will evolve from fundamental transport physics toward broader microbial ecology questions.

Work environment:
Supervision: Waisbord Nicolas and Jean-François Rupprecht, respectively Associate Professor AMU and CNRS Researcher and the Laboratoire de Chimie Bactérienne & Laboratoire Adhésion Inflammation, Marseille, respectively.
Equipment: Complete microfluidic platform (micro-fabrication and microscopy). Collaborations: Microbial ecologists for sampling and field studies.
PhD funding: PhD thesis already funded (3 years guaranteed after internship). PhD start: anytime in 2026. Internship duration: 6 months (flexible dates, ideally February-July or March-August 2026).

To apply: Informal inquiries are welcome. Please send us a CV, M1 and M2 transcripts, motivation letter (1 page max explaining your interest in this project at the physics/biology/ecology interface) and contacts of 1-2 references to: nwaisbord@imm.cnrs.fr and rupprecht.jf@gmail.com.
References
● Waisbord et al., Nature Communications (2021) - Fluidic bacterial diodes rectify magnetotactic cell motility in porous environments
● Petroff et al., eLife (2025) - Optimal navigation in pore networks
● Codutti et al., eLife (2025) - Physiological magnetic fields and navigation in simulated sediments]]> rupprecht.jf Thèses hors de l'EDPIF Sat, 08 Nov 2025 16:38:15 +0100 https://www.edpif.org/phorum/read.php?2,444,444#msg-444 https://www.edpif.org/phorum/read.php?2,444,444#msg-444 here
Send your CV to contact@a51tx.com and fill the form here
...and feel free to share with your network.

The A51 Team]]> A51 Offres d'emploi/Job offers Thu, 06 Nov 2025 20:55:53 +0100 https://www.edpif.org/phorum/read.php?3,443,443#msg-443 https://www.edpif.org/phorum/read.php?3,443,443#msg-443 M2 Internship + possibly funded PhD position

Complex systems are characterized by the presence of a large number of interacting entities. Such systems exhibit a wide variety of behaviors of great scientific interest, including chaotic dynamics, phase transitions (statistical physics), protein interaction networks (biology), ecosystem stability (ecology), and knowledge networks (social epistemology). These examples show that complex systems are ubiquitous across disciplines, from the natural to the social sciences, and require interdisciplinary approaches.

In the current context of the biodiversity crisis, theoretical analyses are crucial complements to field studies, helping to better understand the interdependence between species. A recent study [1], conducted jointly by the Theoretical Physics group (ΦTh) at the UTINAM Institute (CNRS/UMLP) and researchers from iDiv (Halle–Jena–Leipzig), proposed a method to quantify the importance of species (nodes) within trophic networks (predator–prey systems). This internship aims to extend that method to quantify the importance of the links in the network (trophic interactions). The main tasks of the intern will include :
— Gaining a solid understanding of the core algorithm used to quantify link importance in a network, based on Markov chains and eigenvector centrality.
— Developing algorithms, in compiled (Fortran, C++, etc.) and/or interpreted languages (Python, etc.), for network analysis (centrality, trophic levels, coherence), sensitivity (random matrices, random walks on networks), and dynamics (integrators, systems of differential
equations).
— Exploring the dynamic aspects of predator–prey relationships through the study of the stability of fixed points, particularly in non-Hamiltonian and chaotic systems.
— Collaborating with researchers from other academic fields (theoretical ecology, theoretical geography, etc.).
Internship allowance: approximately 700/month
Duration : 3 to 6 months, depending on the candidate’s academic program.
Location : UTINAM Institute, CNRS / Université Marie et Louis Pasteur, Besançon, France
PhD continuation: Strong potential for a funded PhD position.

Supervisors :
— José Lages, Professor, UTINAM CNRS/UMLP jose.lages@univ-fcomte.fr [perso.utinam.cnrs.fr]
— Guillaume Rollin, Associate Professor, UTINAM CNRS/UMLP guillaume.rollin@univ-fcomte.fr
— Benoit Gauzens, Researcher, iDiv Leipzig benoit.gauzens@idiv.de

Références
[1] Rollin, G., Kortsch, S., Lages, J., & Gauzens, B. (2024). Identifying important species in meta-communities. Methods in Ecology and Evolution, 15, 1691–1703. https://doi.org/10.1111/2041-210X.14384]]> lages Thèses hors de l'EDPIF Thu, 30 Oct 2025 00:45:58 +0100 https://www.edpif.org/phorum/read.php?3,442,442#msg-442 https://www.edpif.org/phorum/read.php?3,442,442#msg-442 CIFRE PhD Thesis: Fluid Mechanics / Cryogenic Distillation

Thesis offer in French: https://drive.google.com/file/d/14xbj-Kw92oCmgdG90d_70gU3w26zHpQg/view?usp=sharing

Distillation is the most common separation process used in industry, but it comes at a high cost, representing about 7% of the energy consumption in an industrialized country. In large industrial units, such as Air Liquide's cryogenic air separation units (ASUs) , distillation relies on columns filled with corrugated-crossed structured packings to facilitate contact between liquid and vapor phases. Improving the efficiency of these packings is core to developing innovative, low-energy solutions.

A major challenge posed by these structured packings is achieving optimal liquid distribution. The liquid must flow evenly down the packing sheets; a poor distribution is directly linked to low distillation performance. This thesis will focus on a new configuration of structured packings that demonstrates an exceptional capacity to distribute the liquid.

The goal of the PhD is to experimentally study and understand the liquid flows within a model system at ambient temperature. The student will set up and utilize advanced flow visualization experiments, including:

- Visualizing flow structures with a high-speed camera.
- Measuring instantaneous local liquid film thickness (Chromatic Confocal Imaging).
- Measuring the liquid film thickness field (fluorescence intensity).

We will analyze the stability of liquid films, coherent structures, and mixing effects induced by surface patterns and perforations. This involves studying various flow regimes (covering film, rivulets, menisci), the effect of liquid physical properties (viscosity, surface tension), and control parameters (flow rate, injection points).

This work lies at the confluence of fluid mechanics, process engineering, and energetics. The ideal candidate will have an engineer or M2 level background in one of these fields. Key skills include Python programming , a strong physical sense, and a taste for experimental design.

Offer Details

Opening: 3-year CIFRE PhD thesis
Start Date: From January 2026 (flexible, start date in 2026)
Environment: The thesis is a collaboration between Air Liquide (Paris Innovation Campus) and CentraleSupélec (LGPM Laboratory, University Paris-Saclay).

Contacts
Hervé Duval (CentraleSupélec) herve.duval@centralesupelec.fr

Lionel VINCENT (Air Liquide) lionel.vincent@airliquide.com

Manasa PERIYAPATTANA (Air Liquide) manasa.periyapattana@airliquide.com

References
[1] Iyer, M., Casalinho, J., Seiwert, J., Wattiau, L., Duval, H. Experimental study of a liquid film flowing over a perforation. AIChE Journal, 2021; 67, e17363.
[2] Iyer, M., Casalinho, J., Pachon-Morales, J., Seiwert, J., Wattiau, M., Zimmer, L., Duval, H. A comprehensive study of the liquid transfer from the front to the back of a vertical perforated sheet. AIChE Journal, 2022, 68, e17655.
[3] Iyer, M., Vincent L, Casalinho, J., Pachon-Morales, J., Wattiau, M., Zimmer, L., Duval, H. Visualization of recirculation zones over a perforated plate: An optical flow technique for characterization of fluid dynamics in structured packing. Chemical Engineering Research and Design, 2023, 194:542-549.]]> oriane.devigne Thèses hors de l'EDPIF Fri, 24 Oct 2025 09:54:24 +0200 https://www.edpif.org/phorum/read.php?3,441,441#msg-441 https://www.edpif.org/phorum/read.php?3,441,441#msg-441
"Modeling cavities in crystals at the nanoscale : atomic and meso scale simulations"

Keywords: crystalline defects, atomic scale simulations, meso-scale dislocation dynamics

Cavities are often at the origin of the damage of materials. Examples include : ductile fracture initiation in metals [1, 2], fatigue, damage related to hydrogen storage, dewetting of thin films, cavitation by electromigration in microelectronics... Modeling the first stages of cavity formation is key to the development of more resistant materials.
In this research project, we propose to study crack nucleation in metals by the formation of nanoscale cavities originating from the condensation of vacancies. It is a methodological challenge which combines the diffusion of vacancies, their aggregation on pre-existing defects in the crystal (grain boundaries and dislocations) and the local mechanical stresses which originate from specific dislocations arrangements which are not well known. Therefore, two length scales and long timescales have to be dealt with. The elementary vacancy jumps on the crystal lattice are at the atomic scale and over long time scales (several µs at the temperature considered), i.e. way beyond the capabilities of Molecular Dynamics. Dislocation structures, on the other hand, have micrometer dimensions. We plan to develop an interconnection between two different simulation codes dealing with each of these aspects.
We have recently developed an atomic scale Monte Carlo (MC) method [5] capable of sampling the vacancy clusters configurations, within the framework of classical statistical mechanics, in complex crystalline structures, such as grain boundaries and including the effect of mechanical stresses. Preliminary results reveal that the interaction of the vacancy with the other defects, prior to the application of stress is of primary importance. Therefore, the code needs to be extended to more realistic defect configurations, for example, a dislocation impinged on a grain boundary. The second aspect of the problem will be explored by producing and analyzing three dimensional dislocation arrangements by a meso scale discrete dislocation dynamics code [6]. The idea will be to transfer the local stress levels from the dislocation scale to the atomic scale within the MC code.

The project will start by an M2 internship and could be extended by a PhD thesis (funding already obtained). The PhD subject will be the continuation of the master, with the main goal of finding the specific arrangements of defects that could lead to the formation of cavities at stress levels compatible with experiments, but with some flexibility depending on the interests and skills of the candidate. The focus will be put either on the simulation methodology, or the subject could be opened to experiments.
The first route could explore another important aspect of simulations, with the use of Machine-Learning Interatomic Potentials (MLIPs) to assess the reliability of atomic interactions. Using those efficient and highly accurate tools [7, 8] in the Monte-Carlo simulations will require thoughtful implementation work, including the interfacing with the LAMMPS software to use existing and efficient (CPU/GPU) MLIP frameworks, finding clever algorithmic optimization tricks to speed up calculations and an extensive exploration of state-of-the-art MLIP solutions. Ideally, MC could be used for active learning using well chosen configurations for Density Functional Theory (DFT) calculations.
The second route will consist in performing in situ tensile tests within an electron microscope and nano scale deformation field measurements (at iLM). The idea will be to observe experimentally the location where the nano scale cavities appear, in particular their position with respect to intense slip bands (Fig. 1b). For this, brand new experimental facilities at our partner in Paris (https://pimm.artsetmetiers.fr/) will be used : a Plasma Focused Ion Beam coupled to high resolution Electron Back Scattered Diffraction.

The team will be composed of : Döme Tanguy (CNRS, Monte Carlo / experiments), Ronan Madec (CEA, Dislocation Dynamics), Dylan Bissuel (engineer U Claude Bernard Lyon1, Machine Learning) and Thomas Niehaus (professor U Claude Bernard Lyon 1, Density Functional Theory).

Technical skills: The candidate should have an appetite for code development (C/C++…), for production/analyses of large sets of numerical simulations (Linux) and for microscopic physics. Nevertheless, the initial programming skills can be limited (C and python) and will be extended during the project.

Location : Institut Lumière Matière (iLM), université Lyon 1 [ilm.univ-lyon1.fr]
Contact: dome.tanguy@univ-lyon1.fr

Bibliography:
[1] "Do voids nucleate at grain boundaries during ductile rupture?" P. Noell et al. acta mater. 137 103-114 (2017)
[2] “Void nucleation during ductile rupture of metals: A review” P. J. Noell et al. Prog. Mat. Sci. 135 101085 (2023)
[3] “Fatigue damage of ultrafine-grain copper in very-high cycle fatigue region” P. Lukáš et al. Mat. Sci. Eng. A 528 (2011) pp. 7036-7040
[4] "Slip band-grain boundary interactions in commercial-purity titanium" Y. Guo et al. acta mater. 76 1-12 (2014)
[5] “Sampling vacancy configurations with large relaxations using Smart Darting” D. Tanguy Phys. Rev. Mat. 8 033604 (2024)
[6] “On the role of cross-slip and collinear annihilation in dynamic recovery annihilation” R. Madec, B. Devincre and L. Kubin, Modelling Simul. Mater. Sci. Eng. 33 015010 (2025)
[7] "Machine-learning interatomic potentials for materials science" Y. Mishin Acta Mater 214 116980 (2021)
[8] "Machine Learning Force Fields" O. T. Unke et al. Chem Rev 121 10142–10186 (2021) ]]> dtanguy Thèses hors de l'EDPIF Tue, 14 Oct 2025 15:42:24 +0200 https://www.edpif.org/phorum/read.php?3,440,440#msg-440 https://www.edpif.org/phorum/read.php?3,440,440#msg-440 Optimal random walks of swimming bacteria

Random walks are a cornerstone of statistical physics. While Brownian motion has long been under scrutiny, there is a growing interest in a different type of motion: persistent random walks. Examples abound in active matter and biological world, from self-propelled particles and crawling cells to foraging animals and a plethora of swimming micro-organisms. The statistical properties of such random motions are often unknown yet they play a key role in many vital functions of the organisms and ultimately in their survival.

One striking instance of persistent random motion is the run-and-tumble of bacteria. Bouts of persistent motion ("run") are interspersed with sudden changes of direction ("tumble"). Recent research reveals that bacteria display a fascinating repertoire of swimming patterns, which differ in their run and tumble characteristics. Why? Which benefits come with each swimming strategy? Why were they selected by billions of years of evolution? In spite of some recent progresses [1], answers remain at the nascent stage.

The goal of the internship is to understand theoretically the statistical properties of encounter of run-and-tumble. To address this question, you will use a combination of numerical simulations and analytical approaches based on the Fokker-Planck equation.

There are many facets of swimming strategies that can be explored in a PhD thesis, from individual properties to collective effects. These include the ability to follow chemical gradients, self-assembly into bands [2] and active clustering. In each of these situations, we will ask whether swimming strategies of bacteria are, in some sense, optimal.

This topic lies at the confluence of statistical physics and active matter (no expertise in biology required). Strong background in one of these fields and a taste for theoretical and numerical approaches would be ideal.

Opening toward a PhD: yes (funding with «bourse ministère»).

Contact:
Francois Detcheverry, francois.detcheverry@univ-lyon1.fr Team Liquides et Interfaces, Institut Lumière Matière, Lyon

References:
[1] Universal law for the dispersal of motile microorganisms in porous media,
Pietrangeli, Foffi, Stocker, Ybert, Cottin-Bizonne, Detcheverry. Physical Review Letters (2025)
[2] Exact model of aerotactic band: From Fokker-Planck equation to band structure and fluid flow,
Detcheverry. arXiv (2025).

See full offer here [choose "save link/ target as" or "open as a new window"]]]> François Detcheverry Thèses hors de l'EDPIF Mon, 13 Oct 2025 09:56:40 +0200 https://www.edpif.org/phorum/read.php?3,439,439#msg-439 https://www.edpif.org/phorum/read.php?3,439,439#msg-439 Microphase separation of living cells

Self-organization of cells is central to biological systems and understanding the underlying mechanisms is a long-standing quest. Our recent experiments on the model organism Dictyostelium discoideum show that those motile cells can spontaneously self-assemble into compact aggregates with a characteristic size of 100 μm (see Figure 1 in full offer below). The phenomenon is in fact akin to a microphase separation [1].

Microphase separation is an equilibrium phenomenon where the formation of domains is induced by competing interactions, usually a short-range attraction opposed by a long-range repulsion. Over the last 40 years, the phenomenon has been recognized in several physical systems, from magnetic films and superconductors to liquid crystals, colloids and copolymers. However, it has never been observed with living cells. The experiments of Figure 1 (see full offer below) thus raise a host of questions.

The goal of the internship is to explore the microphase separation of cells using numerical simulations. Our model describes each cell individually and account only for the essential ingredients: adhesion between cells, consumption of oxygen and motion toward oxygen-rich regions. The simulations so far provide an understanding of the domain size but many facets of the microphase separation deserve to be explored, from the various morphologies possible to the dynamic properties of the very mobile domains.

The student will exploit and expand a simulation code that is already functional. A taste for numerical techniques is desirable. No background in biology is required. The work lies at the interface of statistical physics, biophysics and active matter.

Opening toward a PhD: yes (funding with «bourse ministère»).

Francois Detcheverry, francois.detcheverry@univ-lyon1.fr Team Liquides et Interfaces, Institut Lumière Matière, Lyon
Jean-Paul Rieu, jean-paul.rieu@univ-lyon1.fr Team Biophysics .

Reference:
[1] Microphase separation of living cells. Carrère et al. Nature Communications (2023).

See full offer here [choose "save link/ target as" or "open as a new window"]]]> François Detcheverry Thèses hors de l'EDPIF Mon, 13 Oct 2025 09:46:38 +0200 https://www.edpif.org/phorum/read.php?3,438,438#msg-438 https://www.edpif.org/phorum/read.php?3,438,438#msg-438 Theory of Marangoni spreading

Drop some dishwasher liquid or soapy water over a pool of clean water and it will spread outward over the the pool’s surface. The basic physics behind this daily phenomenon is well-known: Surfactant molecules such as soap gather at the air-water interface and locally alter the surface tension, inducing a flow in the underlying water. This kind of Marangoni effect has long been studied and is understood in a variety of phenomena, such as in the celebrated tears of wine [1].

It may therefore come as a surprise that Marangoni spreading, seen daily in the kitchen, has long evaded an exact mathematical description. Some recent progress [2] indicates that surfactant transport can be mapped to a single complex Burgers equation, which allows to identify a complet set of exact solutions. They reveal that the non-linearity of the spreading problem gives rise to a rich variety of behaviors and that the initial surfactant distribution has a key influence on the subsequent evolution.

The goal of the internship is to investigate, theoretically, Marangoni spreading. Beyond the simplified one-dimensional model situation considered so far, there is a host of situations that await exploration: from two-dimensional spreading to finite-depth pool and Marangoni swimmers that self-propel by releasing surfactant. The student will combine two approaches: analytical calculations and numerical simulations within the framework of an electrostatic analogy.

The internship is a first step toward a PhD thesis. This topic lies at the confluence of soft matter, fluid mechanics and statistical physics. Strong background in one of these fields and a taste for theoretical and numerical approaches would be ideal.

Opening toward a PhD: yes (funding with «bourse ministère»).

Contacts:
Francois Detcheverry, francois.detcheverry@univ-lyon1.fr Team Liquides et Interfaces, Institut Lumière Matière, Lyon
Thomas Bickel, thomas.bickel@u-bordeaux.fr Team Theory of Condensed matter, LOMA, Bordeaux


References:
[1] Capillarity and wetting phenomena: drops, bubbles, pearls, waves, De Gennes et al, (Springer Verlag, 2004).
[2] Exact solutions for viscous Marangoni spreading, Bickel and Detcheverry, Physical Review E (2022).

See full offer here [choose "save link/ target as"]]]> François Detcheverry Thèses hors de l'EDPIF Fri, 10 Oct 2025 19:15:42 +0200 https://www.edpif.org/phorum/read.php?3,437,437#msg-437 https://www.edpif.org/phorum/read.php?3,437,437#msg-437 The proposed method involves significantly modifying/improving an experimental system [1,2,3] whose basis has already been developed at LOMA for other fields of application. The originality of our new device is that it will enable independent determination of the size, refractive indices (real and imaginary) and temperature of a glass former nanoparticle optically trapped at a wavelength of 1064 nm [4,5]. The addition of an extra CO2 laser will enable us to finely control the temperature of the nanoparticle whose position is resolved in 3D using ultra fast interferometric detection [1,5]. We will then be able to measure in situ changes in expansion coefficients and indices [2], and deduce the glass transition temperature of a synthesized [4,5] single glass former nanoparticle as a function of its radius. These results will then be analyzed in the context of the team's recent theoretical predictions for fragile glasses suggesting a crucial role of cooperative effects and surface mobility [6,7].



[1] Y. Amarouchene, L. Ondic, M. Mangeat, T. Guerin, D.Dean and Y. Louyer, Nonequilibrium dynamics induced by
scattering forces for optically trapped nanoparticles in strongly inertial regimes. Phys. Rev. Lett. 122, 183901 (2019).
[2] M. Lavaud, T. Salez, Y. Louyer, and Y. Amarouchene, Stochastic inference of surface-induced effects using Brownian motion. Phys. Rev. Res. 3, L032011 (2021).
[3] A, Alexandre, M, Lavaud, N, Fares, E, Millan, Y, Louyer, T. Salez, Y. Amarouchene, T, Guerin, and D. S.
Dean, Non-Gaussian Diffusion Near Surfaces. Phys. Rev. Lett. 130, 077101 (2023).
[4] J. Millen, T. Deesuwan, P. Barker, and J. Anders, Nanoscale temperature measurements using nonequilibrium
Brownian dynamics of a levitated nanosphere, Nat. Nanotechnol. 9, 425 (2014).
[5] E Hebestreit, R Reimann, M Frimmer and L Novotny, Measuring the internal temperature of a levitated
nanoparticle in high vacuum, Phys. Rev. A. 97, 4 043803 (2018).
[6] M. Arutkin, E. Raphael, J. A. Forrest, and T. Salez. Cooperative strings in glassy nanoparticles. Soft. Matter.
13, 141 (2017).
[7] T. Salez, J. D. McGraw, K. Dalnoki-Veress, E. Raphael, and J. A. Forrest. Glass transition at interfaces. Eur. Phys.
News. 48, 24 (2017).]]> AMAROUCHENE Thèses hors de l'EDPIF Fri, 26 Sep 2025 16:16:38 +0200 https://www.edpif.org/phorum/read.php?2,436,436#msg-436 https://www.edpif.org/phorum/read.php?2,436,436#msg-436 conduct and analyse experiments aimed at understanding the experimental properties
of a new type of hybrid optomechanical system: polaritonic drums.

For more detail see the attached document]]> Frédéric Chevy Offres d'emploi/Job offers Wed, 20 Aug 2025 08:13:10 +0200 https://www.edpif.org/phorum/read.php?3,435,435#msg-435 https://www.edpif.org/phorum/read.php?3,435,435#msg-435
Proposition détaillée]]> Frédéric Chevy Thèses hors de l'EDPIF Wed, 02 Jul 2025 09:48:06 +0200 https://www.edpif.org/phorum/read.php?3,434,434#msg-434 https://www.edpif.org/phorum/read.php?3,434,434#msg-434
The goal of the project MicroTera funded by the French Agence nationale de la recherche (ANR) is the development and characterization of THz pulse generation from femtosecond laser-induced micro-plasmas produced in gases under tight focusing conditions. Experiments will be performed by the project partner at Laboratoire de Physique de l’Ecole Normale Supérieure (LPENS) in Paris, while theory and numerical modeling will be carried out by CELIA and ILM. The necessary high-performance computing (HPC) resources will be made
available as part of the project CNARO granted by the Grand équipement national de calcul intensif (GENCI).
Thesis objective: The objective of this thesis is to investigate the physics of laser-generated micro-plasmas and to improve our understanding of their low-frequency emissions. The problem will be approached in three ways: by simplified analytical modeling of the local THz source, rigorous numerical simulations of the generation of the micro-plasma and its secondary emissions, and finally comparison of the theoretical results with corresponding experimental data. The proposed work is thus mainly oriented towards analytical modeling and numerical simulation. The principal numerical tools, a unidirectional pulse propagator and a Maxwell fluid code, are developed at ILM and CELIA. The PhD student will have extended stays in both laboratories, in order to get in-depth training and contribute to the further development of these codes. At least one extended visit of the LPENS lab is foreseen, so the student can get some hands-on experience with the experiments.
The thematical framework of the thesis is rather broad, ranging from fundamental research in plasma physics and theoretical modeling of light matter interaction over HPC code development to very applied THz source development and optimization. The respective weights of these different aspects can be, to some extent, adjusted according to the profile of the candidate.

The candidate must have advanced training in fundamental physics and/or scientific computing, with an ability to handle massively parallel simulation codes and to contribute to their development. Experience with Python, Fortran, C, or C++ and MPI or OpenMP is welcome.

Thesis supervisors: Stefan Skupin – Institut Lumière Matière, UMR 5306 - CNRS, Université de Lyon 1
Luc Bergé – Centre Lasers Intenses et Applications, Université de Bordeaux, CNRS, CEA

Contact:
Luc Bergé – luc.berge@cea.fr or luc.berge@u-bordeaux.fr – +33 (0)5 40 00 33 66
Centre Lasers Intenses et Applications, Université de Bordeaux, CNRS, CEA, 33405 Talence, France
Stefan Skupin – stefan.skupin@cnrs.fr or stefan.skupin@univ-lyon1.fr – +33 (0)4 72 43 15 65
Institut Lumière Matière, UMR 5306 - CNRS, Université de Lyon 1, 69622 Villeurbanne, France]]> Frédéric Chevy Thèses hors de l'EDPIF Sun, 22 Jun 2025 23:35:08 +0200 https://www.edpif.org/phorum/read.php?3,433,433#msg-433 https://www.edpif.org/phorum/read.php?3,433,433#msg-433
Thesis objective: The application range of terahertz (THz) radiation, which lies between the microwave and infrared, historically encompasses astronomy, imaging, remote sensing, chemical spectroscopy, as well as linear and nonlinear condensed matter studies. For all these applications, broadband THz sources at high repetition rates are primordial. Laser-induced micro-plasmas are promising candidates for such THz sources, which can also be cheap and compact.

The goal of the project MicroTera funded by the French Agence nationale de la recherche (ANR) is the development and characterization of THz pulse generation from femtosecond laser-induced micro-plasmas produced in gases under tight focusing conditions. Experiments will be performed by the project partner at Laboratoire de Physique de l’Ecole Normale Supérieure (LPENS) in Paris, while theory and numerical modeling will be carried out by CELIA and ILM. The necessary high-performance computing (HPC) resources will be made available as part of the project CNARO granted by the Grand équipement national de calcul intensif (GENCI).

The objective of this thesis is to investigate the physics of laser-generated micro-plasmas and to improve our understanding of their low-frequency emissions. The problem will be approached in three ways: by simplified analytical modeling of the local THz source, rigorous numerical simulations of the generation of the micro-plasma and its secondary emissions, and finally comparison of the theoretical results with corresponding experimental data. The proposed work is thus mainly oriented towards analytical modeling and numerical simulation. The principal numerical tools, a unidirectional pulse propagator and a Maxwell fluid code, are developed at ILM and CELIA. The PhD student will have extended stays in both laboratories, in order to get in-depth training and contribute to the further development of these codes. At least one extended visit of the LPENS lab is foreseen, so the student can get some hands-on experience with the experiments.

The thematical framework of the thesis is rather broad, ranging from fundamental research in plasma physics and theoretical modeling of light matter interaction over HPC code development to very applied THz source development and optimization. The respective weights of these different aspects can be, to some extent, adjusted according to the profile of the candidate.

The candidate must have advanced training in fundamental physics and/or scientific computing, with an ability to handle massively parallel simulation codes and to contribute to their development. Experience with Python, Fortran, C, or C++ and MPI or OpenMP is welcome.

Thesis supervisors: Luc Bergé – Centre Lasers Intenses et Applications, Université de Bordeaux, CNRS, CEA, 33405 Talence, France
Stefan Skupin – Institut Lumière Matière, UMR 5306 - CNRS, Université de Lyon 1, 69622 Villeurbanne, France

PhD School : Ecole Doctorale de Physique et Astrophysique de l’Université de Lyon (Ecole doctorale n°52)

Contact: Luc Bergé – luc.berge@cea.fr or luc.berge@u-bordeaux.fr – +33 (0)5 40 00 33 66 – Centre Lasers Intenses et Applications, Université de Bordeaux, CNRS, CEA, 33405 Talence, France
Stefan Skupin – stefan.skupin@cnrs.fr or stefan.skupin@univ-lyon1.fr – +33 (0)4 72 43 15 65 – Institut Lumière Matière, UMR 5306 - CNRS, Université de Lyon 1, 69622 Villeurbanne, France

Funding: Agence nationale de la recherche (ANR), Project AAPG 2024 MicroTera]]> Stefan Skupin Thèses hors de l'EDPIF Sat, 21 Jun 2025 10:22:04 +0200 https://www.edpif.org/phorum/read.php?3,432,432#msg-432 https://www.edpif.org/phorum/read.php?3,432,432#msg-432 In particular, cuprite (Cu₂O) is a remarkable semiconductor that exhibits excitons (electron-hole pairs) of gigantic size (>1000 times larger than normal [1]), known as 'Rydberg excitons'. By analogy with their atomic counterparts (Rydberg atoms) and their numerous successes in quantum technologies [2-3], Rydberg excitons represent an emerging platform with great potential for implementing integrated quantum devices within a semiconductor.
However, currently, only natural materials have the required purity for such devices. These natural crystals are difficult to structure and are becoming increasingly rare (as the mines that produce them are being depleted). Finding a chemical synthesis route to produce high-purity artificial Cu₂O, which can also be structured at will, is therefore a major and urgent challenge for Cu₂O-based quantum technologies.

This three-year PhD, which is funded by INSA-Toulouse (BTES-INSA), will be conducted at the Laboratoire de Physique et Chimie des Nano-Objets (LPCNO) starting in October 2025. It includes a 15000€ allowance for conferences.

The PhD student will be trained in ultra-precise optical measurements of excitons and will explore multiple synthesis methods for Cu₂O. The most promising approach involves the direct growth of Cu₂O microcrystals under hydrothermal conditions (aqueous synthesis at high pressure). These conditions tend to produce crystalline particles with well-defined exposed facets. The crystals/particles obtained through these methods will be characterized using electron microscopy and X-ray diffraction before being used for their quantum properties.

Desired Profile:
• Background in Condensed Matter Physics and/or Chemistry, Materials Science specialization
• Curiosity, motivation and scientific rigor
• Strong communication and writing skills, in English and/or French

References:
[1] Kazimierczuk, Tomasz, et al. "Giant Rydberg excitons in the copper oxide Cu₂O." Nature 514.7522 (2014): 343-347.
[2] Saffman, Mark, Thad G. Walker, and Klaus Mølmer. "Quantum information with Rydberg atoms." Reviews of Modern Physics 82.3 (2010): 2313.
[3] Peyronel, T, et al. "Quantum nonlinear optics with single photons enabled by strongly interacting atoms." Nature 488.7409 (2012): 57-60.]]> Thomas Boulier Thèses hors de l'EDPIF Thu, 19 Jun 2025 17:06:39 +0200 https://www.edpif.org/phorum/read.php?2,431,431#msg-431 https://www.edpif.org/phorum/read.php?2,431,431#msg-431
The project, funded by CNRS, aims to develop theoretical and numerical models of plant cell wall growth, focusing on the coupling between mechanical stress, plant pressure, and cell wall swelling. The recruited postdoc will work on multiscale modeling exploring how stochastic biochemical and mechanical processes contribute to tissue expansion and shape regulation.

We are looking for candidates with a background in theoretical physics, applied mathematics, or biophysics. Experience with soft matter, PDEs, or stochastic modeling will be appreciated.

Please find a detailed description of the offer here:

[www.normalesup.org]

Deadline to apply: August 1, 2025
Contact and application: antoine.fruleux@cnrs.fr]]> antoine.fruleux@cnrs.fr Offres d'emploi/Job offers Wed, 11 Jun 2025 16:51:05 +0200 https://www.edpif.org/phorum/read.php?3,430,430#msg-430 https://www.edpif.org/phorum/read.php?3,430,430#msg-430 Two fully-funded PhD positions in machine learning for gene regulatory dynamics

Full announcement here.

The newly opened Ricci Lab at Institut Imagine in Paris, one of Europe's top biological research centers, is seeking two Ph.D. students to work on data-driven dynamical systems modeling of genetic disease. Our lab's main goal is to build models which predict how biological systems (gene regulatory networks, cells, tissues) evolve in time and to understand how to intervene in these systems to minimize the health impact of complex genetic diseases.

Located in the heart of Paris, our lab welcomes candidates with strong backgrounds in applied mathematics, physics, computer science, or computational biology. The successful candidate will have had coursework and/or previous research experience in some of the following:

– Differential equations or dynamical systems
– Control theory or reinforcement learning

As part of our lab, you will have access to world-class computational and biological resources and will have the opportunity to collaborate with scientists at affiliated institutions like Institut Pasteur, PR[AI]RIE, Institut Necker, and others. Successful applicants will receive a PhD in Computational or Mathematical Biology from Université Paris Cité.

To apply, please send a CV, contact information for two references, and a brief description of relevant coursework and/or research experience (~ 1 page) to matthew.ricci@institutimagine.org with`phd` in the subject line. Applications will be reviewed on a rolling basis starting June 15, 2025. The intended start date is September 1, 2025, but this is flexible.]]> mgricci Thèses hors de l'EDPIF Mon, 09 Jun 2025 17:14:54 +0200 https://www.edpif.org/phorum/read.php?3,428,428#msg-428 https://www.edpif.org/phorum/read.php?3,428,428#msg-428 adum.fr
Contact doux@lpsc.in2p3.fr

Mots clés
Cosmologie, Structure et expansion de l'Univers, Lentille gravitationnelle, Energie noire, Machine learning

Profil et compétences recherchées
- Titulaire d'un master 2 en physique fondamentale, cosmologie, astrophysique et domaines reliés.
- Compétences en programmation scientifique en python (ou autres langages), expériences pratiques en Machine-Learning ou simulations seront des atouts
- Maîtrise de l'anglais (parlé, lu et écrit)
- Travail en équipe, communication, éthique
- Motivation, curiosité

Résumé du projet de thèse
Depuis la découverte de l'expansion accélérée de l'Univers il y a environ 25 ans, la cosmologie moderne est confrontée à un défi majeur : déterminer la nature de l'énergie noire. Le modèle cosmologique standard, ΛCDM, suggère que cette expansion est pilotée par une forme d'énergie à pression négative, mais l'explication physique de ce phénomène reste inconnue. Pour percer ce mystère, de grands relevés astronomiques vont cartographier le ciel avec une profondeur et une précision sans précédent. Parmi ces initiatives, l'observatoire Vera C. Rubin au Chili, s'apprête à réaliser la cartographie la plus détaillée de l'ensemble du ciel austral pendant une durée de 10 ans, baptisée LSST (Legacy Survey of Space and Time). Pour cela, l'observatoire est équipé d'un télescope optique grand champ et de la plus grande caméra numérique au monde : 3,2 milliards de pixels. L'observatoire prend en ce moment même ses premières images sur le ciel, le début du relevé LSST est prévu dès cet automne. En même temps, Euclid, la mission de l'ESA lancée en 2023, et le télescope spatial Nancy Grace Roman de la NASA, dont le lancement est prévu en 2027, joueront un rôle crucial et offriront des données fortement complémentaires.

Ces relevés observeront notamment le phénomène de lentille gravitationnelle faible, ou cisaillement cosmique, une déformation subtile des images des galaxies lointaines par la distribution de matière dans l'Univers. La cartographie de cette déformation est essentielle pour étudier la structure à grande échelle de l'Univers et son expansion, et donc pour contraindre les propriétés de l'énergie noire. Cependant, l'interprétation des données de ces relevés massifs est confrontée à un défi de taille : le “blending” des sources astronomiques. Il se produit lorsque plusieurs sources astronomiques (galaxies, étoiles, etc.) apparaissent très proches les unes des autres sur les images, au point de se superposer. Cette superposition rend difficile la séparation des sources individuelles et la mesure précise de leurs propriétés (forme, luminosité, distance, etc.). Le “blending” introduit ainsi des erreurs systématiques dans les mesures cosmologiques, ce qui peut biaiser les conclusions sur l'énergie noire et d'autres paramètres fondamentaux de l'Univers.

L'objectif principal de cette thèse est de développer des techniques innovantes pour caractériser et corriger les effets du “blending” dans les données du LSST, en tirant parti des observations complémentaires d'Euclid et Roman (sans distorsion atmosphérique, et donc moins impactées). La thèse démarrera par la caractérisation du “blending” dans les données de commissioning de LSST récemment collectées, en utilisant des méthodes probabilistes développées par l'équipe. Ensuite, on s'intéressera à l'impact du “blending” sur différentes mesures (lentille gravitationnelle, “clustering” de galaxies) grâce à des simulations cosmologiques, ce qui permettra de développer des stratégies d'atténuation du “blending” à l'aide de l'apprentissage automatique, notamment des réseaux de neurones probabilistes. Enfin, on adaptera ces méthodes à une analyse conjointe des données de LSST, Euclid et Roman pour optimiser les résultats cosmologiques et les contraintes sur l'énergie noire.

Thématiques
Cosmologie observationnelle, structure et expansion de l'Univers, lentille gravitationnelle, énergie noire et
Machine learning

Objectif et contexte
L'objectif de cette thèse est de développer des techniques multi-instruments pour caractériser et corriger les effets du “blending” dans les données du relevé astronomique LSST, en utilisant les données des télescopes spatiaux Euclid et Roman, afin d'améliorer les mesures cosmologiques et notre compréhension de l'énergie noire.
Structure d'accueil : Le Laboratoire de physique subatomique et de cosmologie (LPSC) est l'une des grandes unités de l’Institut national de physique nucléaire et physique des particules (IN2P3) du CNRS. L'objectif scientifique du LPSC est de répondre aux questions complexes sur les interactions fondamentales à différentes échelles, depuis les briques élémentaires de la matière (physique des particules, physique hadronique et physique nucléaire), jusqu'aux plus grandes échelles (étude des rayons cosmiques d’ultra-haute énergie, physique des astroparticules et cosmologie). Le LPSC présente également des activités dans les thématiques sociétales que sont la santé (physique médicale) et l'énergie (réacteurs nucléaires civils du futur).

Équipe d'accueil : La thèse se déroulera au sein de l'équipe de Cosmologie Observationnelle du LPSC à Grenoble. Les thématiques de recherche de l'équipe couvrent les grands relevés de galaxies LSST et Euclid, la cosmologie multi-longueurs d'onde avec les amas de galaxie, les observations du fond diffus cosmologique dans le domaine millimétrique, et l'étude des phénomènes transitoires (rayons cosmiques et sursauts gamma dans un cadre multi-messagers).

Méthode
Les méthodes de cette thèse combineront une approche probabiliste pour quantifier le “blending” d'objets astronomiques avec des techniques d'apprentissage automatique pour l'identifier et le corriger, notamment des réseaux de neurones probabilistes convolutionnels ou opérant sur des graphes. Par ailleurs, la caractérisation du “blending”, des images aux contraintes cosmologiques, impliquera l'utilisation de simulations pour étudier son impact sur les mesures cosmologiques, et donc la manipulation de catalogues et d'images de galaxies.

Résultats attendus
Les résultats attendus de cette thèse sont : (i) des outils de haute qualité pour évaluer le “blending” dans les données du LSST avec une méthode probabiliste novatrice ; (ii) des catalogues de données augmentés qui permettent d'appliquer différentes stratégies d'atténuation du “blending” ; (iii) une contribution à l'analyse conjointe des données de LSST, Euclid et Roman, contribuant ainsi à leurs études cosmologiques.

En termes d'impact scientifique, on attend : (i) une meilleure compréhension et correction des erreurs systématiques dues au “blending”, ce qui augmentera la précision des mesures cosmologiques ; (ii) des contraintes plus fortes sur les paramètres cosmologiques, notamment ceux liés à l'énergie noire ; (iii) une utilisation optimale des données combinées de plusieurs grands relevés astronomiques.

Précision sur l'encadrement
La personne sélectionnée sera encadrée par Cyrille Doux (membre des collaborations LSST DESC, Euclid et Roman, ancien adjoint scientifique national pour LSST France) et David Maurin (membre de LSST). Des échanges hebdomadaires permettront de faire le point sur l’avancement du projet et impliqueront régulièrement les collaborateurs à l'Université deChicago. L'étudiant ou l'étudiante s’intégrera dans l'équipe de Cosmologie Observationnelle
du LPSC. Elle participera aux réunions de groupes hebdomadaires et aux téléconférences de
LSST DESC (Dark Energy Science Collaboration) où elle devra rendre compte régulièrement
de son travail. Plus largement, elle pourra être amenée à présenter ses travaux dans des
conférences scientifiques. Un suivi de comité de thèse sera mis en place annuellement

Conditions scientifiques matérielles (conditions de sécurité spécifiques) et financières du projet de recherches
Le financement obtenu est une thèse internationale du CNRS en collaboration avec l'Université de Chicago (sans cotutelle ou double diplôme). Ce financement permettra des déplacements en France et à l'étranger en plus de la dotation de l'équipe liée aux projets LSST et Euclid. L'étudiant ou l'étudiante aura accès à un bureau partagé avec un ordinateur portable. Les analyses et simulations seront effectuées au centre de calcul de l'IN2P3. Il n'y a pas de conditions de sécurité spécifiques.

Objectifs de valorisation des travaux de recherche du doctorant : diffusion, publication et confidentialité, droit à la propriété intellectuelle,...
Publications dans des revues internationales à comité de lecture et présentations à des conférences internationales ainsi qu'aux meetings de collaborations. Les codes produits seront tous en libre accès.

Collaborations envisagées
Outre le travail collaboratif avec les membres des équipes LSST et Euclid, une collaboration particulière est envisagée avec l'Université de Chicago avec qui le financement a été demandé.

Ouverture Internationale
Le projet de thèse prendra place au sein de la collaboration scientifique LSST DESC (Dark Energy Science Collaboration), qui regroupe 1100 expert.e.s en cosmologie et en astronomie dans plus de 20 pays. Il s'intègrera également dans le consortium Euclid. Ce contexte se traduira par des téléconférences régulières avec des collaborateurs en Europe, en Amérique du Nord et du Sud, ainsi qu'à des meetings de collaborations annuels.

Références bibliographiques
1. Arcelin, B., Doux, C., Aubourg, E., and Roucelle, C. (2020). Deblending galaxies with variational autoencoders: A joint multiband, multi-instrument approach. Mon. Not. R. Astron. Soc. 500, 531– 547. doi: 10.1093/mnras/staa3062

2. Doux, C., Jain, B., Zeurcher, D., Lee, J., Fang, X., Rosenfeld, R., et al. (2022). Dark energy survey year 3 results: cosmological constraints from the analysis of cosmic shear in harmonic space. Mon. Not. R. Astron. Soc. 515, 1942–1972. doi: 10.1093/mnras/stac1826

3. Gatti, M., Sheldon, E., Amon, A., Becker, M., Troxel, M., Choi, A., et al. (2021). Dark Energy Survey Year 3 Results: Weak Lensing Shape Catalogue. Mon. Not. R. Astron. Soc. 504, stab918. doi: 10.1093/mnras/stab918

4. Guy, L. P., Cuillandre, J.-C., Bachelet, E., Banerji, M., Bauer, F. E., Collett, T., et al. (2022). Rubin-Euclid Derived Data Products: Initial Recommendations. arXiv. doi: 10.5281/zenodo.7195671

5. MacCrann, N., Becker, M. R., McCullough, J., Amon, A., Gruen, D., Jarvis, M., et al. (2021). Dark Energy Survey Y3 results: blending shear and redshift biases in image simulations. Mon Not R Astron Soc 509, 3371–3394. doi: 10.1093/mnras/stab2870

6. Melchior, P., Joseph, R., Sanchez, J., MacCrann, N., and Gruen, D. (2021). The challenge of blending in large sky surveys. Nat Rev Phys 3, 712–718. doi: 10.1038/s42254-021-00353-y

7. Ramel, M., Doux, C., and Kuna, M. (2024). Impact of blending on weak lensing measurements with Rubin-LSST., in 58th Rencontres de Moriond.

8. Sanchez, J., Mendoza, I., Kirkby, D. P., and Burchat, P. R. (2021). Effects of overlapping sources on cosmic shear estimation: Statistical sensitivity and pixel-noise bias. J Cosmol Astropart P 2021, 043. doi: 10.1088/1475-7516/2021/07/043

9. Troxel, M. A., Lin, C., Park, A., Hirata, C., Mandelbaum, R., Jarvis, M., et al. (2023). A joint Roman Space Telescope and Rubin Observatory synthetic wide-field imaging survey. Mon. Not. R. Astron. Soc. 522, 2801–2820. doi: 10.1093/mnras/stad664]]> cdoux Thèses hors de l'EDPIF Thu, 22 May 2025 20:18:13 +0200 https://www.edpif.org/phorum/read.php?2,427,427#msg-427 https://www.edpif.org/phorum/read.php?2,427,427#msg-427 idéalement titulaire de l’agrégation, pour effectuer un enseignement annuel de 384h. La personne recrutée assurera des enseignements de physique mais également de mathématiques appliquées au sein de la Licence Sciences Biomédicales, comprenant la Licence Accès Santé (L.AS) ainsi que la mineure disciplinaire BPC du Parcours Accès Santé Spécifique (PASS).
Date de prise de fonction souhaitée : 01/09/2025

Ce contrat à durée déterminée d’un an est susceptible d’évoluer avec l’ouverture d’un concours visant le recrutement d’un PRAG (statut de fonctionnaire).

Détail du poste
Objectifs pédagogiques et besoins d'encadrement : les activités principales d'enseignement de la personne recrutée incluront la préparation et la dispense des enseignements de physique et de mathématiques appliquées au sein de l’UFR des Sciences Biomédicales. Cela englobera des enseignements de Travaux Dirigés (TD) et de Travaux Pratiques (TP) en présentiel, ainsi que la participation à l'écriture d'exercices de TD, de protocoles de TP et de sujets d'examen. De plus, la personne recrutée sera impliquée dans l'animation d'enseignements utilisant des outils numériques tels que des quiz et des forums en ligne. Elle assurera également la surveillance et la correction des évaluations, ainsi que la réalisation de colles, incluant l'élaboration de sujets et le rôle d’examinateur.

Filières de formation concernées : Licence Sciences Biomédicales, comprenant la Licence Accès Santé (L.AS) ainsi que la mineure disciplinaire BPC du Parcours Accès Santé Spécifique (PASS).


Les candidats intéressés doivent envoyer un mail avec un CV à Marie Claude Fauré et Stéphanie Mangenot, co-responsables des enseignements de physique à l’UFR des Sciences Fondamentales et Biomédicales de l’Université Paris Cité.

Email de contact : marie-claude.faure@u-paris.fr et stephanie.mangenot@u-paris.fr]]> smangenot Offres d'emploi/Job offers Wed, 21 May 2025 10:42:52 +0200 https://www.edpif.org/phorum/read.php?3,426,426#msg-426 https://www.edpif.org/phorum/read.php?3,426,426#msg-426
For more details and to apply: [adum.fr].
Contacts: guido.uguzzoni@cea.fr, jorge.fdcd@ipht.fr.]]> Jorge FdCD Thèses hors de l'EDPIF Sat, 10 May 2025 12:11:02 +0200 https://www.edpif.org/phorum/read.php?3,425,425#msg-425 https://www.edpif.org/phorum/read.php?3,425,425#msg-425
We are looking for candidates for a PhD position on the topic of polariton condensates in confined structures: artificial photonic molecules. This is a joint position between University Clermont Auvergne, France (theory) and TU Dortmund, Germany (experiment), with approximately 50/50 time to be spent in both groups. The candidate will perform theoretical simulations and data analysis related to the experiments and will gain additional experience with the experimental setups while working in TU Dortmund.

The announcements for the position can be found at:

[adum.fr]

[euraxess.ec.europa.eu]

The candidates need to apply before the 20th of May, 2025.

Applications should be addressed to dmitry.solnyshkov@uca.fr

Best regards,
Dmitry Solnyshkov
Prof. at University Clermont Auvergne]]> dsolnyshkov Thèses hors de l'EDPIF Tue, 06 May 2025 12:20:33 +0200 https://www.edpif.org/phorum/read.php?3,424,424#msg-424 https://www.edpif.org/phorum/read.php?3,424,424#msg-424 Contact : Dr. Antoine Carof, Laboratoire de Physique et Chimie Théoriques, UMR 7019
54 000 Nancy, France (antoine.carof@univ-lorraine.fr)

Keyword : Statistical physics, physical chemistry, molecular dynamics, supercritical fluid, confinement

Description of the project : Our research project aims to understand the thermodynamic and structural properties of the supercritical fluids in a complex environment. These particular fluids are common in different technologies, in particular for the development towards more environmentally friendly industrial processes. For example, industrial CO2 emission could be captured directly at the industrial sites and stored in geological reservoirs in its supercritical state.[1] To assess the validity of this strategy, we need to elucidate the structure and the thermodynamics of the supercritical fluids within these multiscale reservoirs. In our group, we are developing the classical density functional theory (cDFT), a powerful statistical field theory based on the molecular density. The cDFT is based on a minimization process which gives (theoretically) the same results as molecular dynamics simulations, but at a cost at least 10,000 times smaller![2] The key challenge is to construct the best density functional, and in particular its excess contribution. We have already started to build the functional for the supercritical CO2, but for now limited to only one thermodynamic condition.[3] Our project is to extend our functional for several conditions, relying on the statistical physics of (molecular) liquids. According to the PhD student interests, the project can then evolve in different directions: (i) the development of the cDFT in the near-critical region, where the divergence of the correlation functions will require particular treatment; (ii) the extension of cDFT for a mixture of supercritical fluids; or (iii) the applications of the cDFT to evaluate the properties of the supercritical fluids in confinement.

Applicant’s profile: Highly motivated students holding a Master’s degree in physical chemistry, theoretical chemistry, physics, or equivalent are strongly encouraged to apply for this post. Strong interest in scripting (e.g., Python, Fortran) and good written and oral communication skills are expected.

Work context: The PhD will take in place at the LPCT. The LPCT studies cover a wide range of topics, from the equilibrium and non-equilibrium dynamics of complex systems - a major issue in contemporary physics and chemistry The LPCT is an equal opportunity laboratory with a working environment actively promoting equality, diversity, and inclusion.

Funding: We acknowledge funding from the Agence Nationale de la Recherche (ANR BAC2MOL). The salary is fixed according to the national policy for PhD salaries in France (about 38k€/year, gross salary). The position gives access to the French Social Security system. An additional grant of 15 k€ will be provided to the PhD student for attending conferences, international mobility, small supplies.

How to apply: send an e-mail to Antoine Carof (antoine.carof@univ-lorraine.fr)

[1] International Energy Agency. CO2 Storage Resources and Their Development; Paris, 2022. [www.iea.org]
[2] Evans, R.; Oettel, M.; Roth, R.; Kahl, G. New Developments in Classical Density Functional Theory. J. Phys.: Condens. Matter 2016, 28 (24), 240401. [doi.org]
[3] Mohamed Houssein, M.; Belloni, L.; Borgis, D.; Ingrosso, F.; Carof, A. Molecular Integral Equations Theory in the near Critical Region of CO2. J. Mol. Liq., 2025, 418. [doi.org]]]> Antoine Carof Thèses hors de l'EDPIF Fri, 04 Apr 2025 14:56:05 +0200 https://www.edpif.org/phorum/read.php?3,423,423#msg-423 https://www.edpif.org/phorum/read.php?3,423,423#msg-423 Development and application of Quantum Subspace-Based Algorithms for energy transition materials
Key words: quantum computing, quantum algorithms, quantum Lanczos, subspace methods, electronic structure, energy materials, CO2 storage and capture, energy conversion.

Context and topic: The modeling of electronic structure of physico-chemical systems rely on solving the Schrödinger equation. Classical subspace-based algorithms, such as the Lanczos method, outperform classical diagonalization algorithms in obtaining precise results but remain computationally expensive. The advent of quantum computing promises a revolution, enabling theoretically accurate simulations of exponentially larger electronic systems. This breakthrough is expected to address societal and environmental challenges, such as the development of new materials for CO2 capture and storage, and energy conversion.

Current quantum computing research on the electronic structure problem has primarily focused on two approaches: hybrid variational quantum eigensolver (VQE) methods for noisy quantum computers, and Quantum Phase Estimation (QPE) algorithms targeting long-term fault-tolerant devices [1,2]. Recently, the adaptation of classical subspace methods to quantum computing has demonstrated a versatile framework [3]. This framework can be adapted to both noisy devices, using physically motivated or variational subspace construction [4-6], and to fault-tolerant devices by explicitly constructing the Krylov subspace using propagators or block encoding [7,8].

In this context and in strong collaboration between the academy (LOMA, University of Bordeaux) and an industrial partner (CIFRE scholarship within TotalEnergies, based in Saclay), this PhD thesis aims to develop, adapt and evaluate quantum subspace methods to simulate the electronic structure of materials. Specifically, the goal are to:

1. Establish and implement an algorithmic framework that enables both noisy (subspace construction) and fault-tolerant (block encoding) quantum simulations, and a comparison with fault-tolerant QPE approaches.

2. Test, benchmark and document the performances of these methods on various electronic systems. The target systems are of interest for the use-case of material design for CO 2 capture. In addition, systems exhibiting strongly-interacting electrons, such as those based on transition metals, will be considered to benchmark the results.

Profile and requirements:
• Master of quantum or condensed-matter physics, quantum or theoretical chemistry.
• Appealing for quantum computing and multi-disciplinary projects.
• Strong taste for numerical work (Python, Quantum packages (Qiskit or myQLM)).

Logistic:
• The PhD will take place mainly in Saclay at TotalEnergy with regular visits in Bordeaux.
• Duration 3 years starting in September 2025.

Contacts:
• Jérémie Messud – jeremie.messud@totalenergies.com
• Matthieu Saubanère – matthieu.saubanere@cnrs.fr

Refs:
[1] B. Bauer, S. Bravyi, M. Motta, and G. K.-L. Chan, Chem. Rev. 120, 12685 (2020).
[2] K. Bharti, A. Cervera-Lierta, T. H. Kyaw, T. Haug, S. Alperin-Lea, A. Anand, M. Degroote, H. Heimonen, J. S.
Kottmann, T. Menke, W.-K. Mok, S. Sim, L.-C. Kwek, and A. Aspuru-Guzik, Rev. Mod. Phys. 94, 015004 (2022).
[3] M. Motta, W. Kirby, I. Liepuoniute, K. J. Sung, J. Cohn, A. Mezzacapo, K. Klymko, N. Nguyen, N. Yoshioka, and J. E.
Rice, Electron. Struct. 6, 013001 (2024).
[4] J. R. McClean, M. E. Kimchi-Schwartz, J. Carter, and W. A. de Jong, Phys. Rev. A 95, 042308 (2017).
[5] Robledo-Moreno et. al., arXiv:2405.05068 (2024).
[6] H. A. Akande, B. Senjean and M. Saubanère, arXiv:2411.16915 (2024)
[7] N. H. Stair, C. L. Cortes, R. M. Parrish, J. Cohn, and M. Motta, Phys. Rev. A 107, 032414 (2023).
[8] W. Kirby, M. Motta, and A. Mezzacapo, Quantum 7, 1018 (2023).]]> matthieu.saubanere@cnrs.fr Thèses hors de l'EDPIF Mon, 17 Mar 2025 09:18:26 +0100 https://www.edpif.org/phorum/read.php?3,422,422#msg-422 https://www.edpif.org/phorum/read.php?3,422,422#msg-422 Magnetotransport in magnetic topological insulator monolayers MnBi₂Te₄:
Toward a Quantum Anomalous Hall device for metrology

As part of an international collaboration between the LNCMI-Toulouse (France) and the IFW-Dresden (Germany), a PhD position (and M2 internship potentially preceding it) is open at LNCMI, for a PhD starting date ideally before 10.2025. The project is a fundamental study of the intrinsic properties of magnetic topological insulators, a fascinating electronic phase of matter recently discovered which demonstrated potential for quantum metrology.

Details on the PhD:
M2 internship: as a pre-PhD internship (preferred but non-mandatory)
Funding: fully funded position through the French-German ANR-DFG project IMAGIN
Location: LNCMI, Toulouse. As the PhD will be in co-tutelle with the IFW-Dresden, regular research
stays (up to a part of the PhD) is planned at IFW (especially for nanofabrication) – to be discussed.
Duration: 3 years (regulatory duration of a PhD thesis in France. Applicants must hold a Master degree)

Background:
The concept of topological phase transition (awarded the Nobel prize for physics in 2016) has triggered intensive research in fundamental physics as well as in applied research in the last 20 years, touching fields as various as material research, optics, electronics, and metrology. In condensed matter, topological systems are characterized by intrinsically metallic interface states surrounding an insulating bulk. While 2D topological phases, such as the Quantum Hall effect (QHE), have metallic 1D edge channels around an insulating surface, 3D topological insulators (3DTI, such as the Bi₂Se₃-Bi₂Te₃ family) display on their surface 2D metallic surface states with fascinating properties (helical spintexture and linear band structure similar to that of graphene).
Recently, a new type of topological system, the magnetic 3DTI MnBi₂Te₄, has been discovered. Beyond surface states, MnBi₂Te₄ has been shown to display the Quantum anomalous Hall effect (QAHE) with quantized conductance of ]]> louis.veyrat Thèses hors de l'EDPIF Fri, 14 Mar 2025 14:36:09 +0100 https://www.edpif.org/phorum/read.php?3,421,421#msg-421 https://www.edpif.org/phorum/read.php?3,421,421#msg-421
PhD Project 1 aims to develop advanced statistical methods based on kinetic theory, utilizing both numerical and analytical approaches, to study charge and heat transport in electron and electron-phonon gases. The project will focus on hydrodynamic transport–a recently observed mode of transport driven by dominant interactions–in both solid-state systems and atomic quantum gases.

PhD Project 2 aims to explore the theoretical foundations of band structure engineering through moiré superpotentials in solid-state systems, and to describe the interplay with the phase diagram and the quantum geometry. This project is part of a jointly funded collaboration with experimentalists and will proceed in close connection with local experimental groups studying graphene and high-temperature superconductivity.

Practical informations : [web103.reachmee.com]]]> felix_werner Thèses hors de l'EDPIF Mon, 17 Feb 2025 09:53:14 +0100 https://www.edpif.org/phorum/read.php?3,420,420#msg-420 https://www.edpif.org/phorum/read.php?3,420,420#msg-420 Context. Many chemists have been confronted, since the groundbreaking Miller–Urey experiment in 1952 or even before, with the difficulty of dealing with large chemical reaction networks comprising hundreds of molecule types or more. Such networks arise in particular in a prebiotic context. The Miller–Urey experiment demonstrated the synthesis of a large diversity of organic molecules from inorganic components, and set out a vast research program aiming at understanding physico-chemical conditions and processes having led to the emergence of life on the early Earth, through a sequence of mostly unknown evolution steps. With the multiplication of observations of exoplanets since 2004, the interest has broadened to the discussion of possible biosignatures attesting to the presence of life elsewhere in the Universe.
Depending on research groups, emphasis has been put either on RNA-first or metabolism-first scenarios. In both cases, the key element to be demonstrated is an evolution mechanism leading to more complex molecules or molecule networks, which could possibly be extrapolated to extant biological systems. In this respect, autocatalytic processes, characterized by linear instabilities of the underlying equations, are expected to play a prominent role.

Challenges. Detection of compounds proceeds through complex GC-MS (gas chromatography/mass spectroscopy) or LC/MS (liquid chromatography/mass spectroscopy) techniques. The mass spectrum of a compound is in the form of a series of peaks. Databases provide only a tiny fraction of these signatures. For samples with a large diversity, only raw formulas are readily accessible; thus, it is impossible to write down a closed list of chemical compounds. Experiments clearly show several time phases, in which new compounds may appear, and then disappear, which are very difficult to interpret.
From the mathematical side, huge progress has been made very recently towards a general characterization of autocatalysis, and beyond that, a semi-quantitative description in terms of hierarchical models of the time behavior of generic chemical reaction networks under a scale-separation hypothesis.

Project. The main goal of the thesis is to fit mass spectroscopy data, derived by chemists interested in the origin of life, with the family of hierarchical models. An adequate statistical method will be built to infer parameters of the hierarchical models, which can be interpreted as proxy kinetic rates. Importantly, a Bayesian prior distribution on the kinetic parameters k of potentially all mechanistically simple chemical reactions has been made available by recent work in computational chemistry, complementing chemical expertise, and allowing the network itself to be inferred. Because only raw formulas are accessible through measurements, the general inference framework is that of a hidden Markov model (HMM), for which a large panel of techniques have been developed, including expectation-maximization (EM) and variational methods.

Outcome. Using the fitted model will make it possible to numerically investigate, at a very low computational cost, a large variety of experimental set-ups, and hopefully give access to time scales beyond the duration of experiments, providing insights about plausible chemical evolution processes of organic matter found on asteroids and planets in their early days after their formation.

Candidate. We are looking for a highly motivated mathematician or theoretical physicist with a background in statistical inference and/or statistical physics, and strong interest in applications and interactions with scientists from very different backgrounds. Some proficiency in algorithmic programming in Python is required.

Situation. The project will be hosted at IECL (Institut Élie Cartan de Lorraine), which is the mathematics laboratory of Université de Lorraine, Nancy, France. The monthly net salary is ca. 2000€. Starting in Fall 2025 or beginning 2026, depending on funding and at the convenience of the selected candidate. The candidate is expected to interact strongly with experimental partner teams in chemistry and astrochemistry in Marseille (PIIM) and Poitiers (IC2MP), and with mixed theoretical/experimental close collaborators in Paris (ESPCI), all part of CNRS-funded program PEPR Origins.

Contact. Send a CV and cover letter to jeremie.unterberger@univ-lorraine.fr and ulysse.herbach@univ-lorraine.fr. Do not hesitate to reach us for further information.

References:



Nghe P., Unterberger J. (2022). Stoechiometric and dynamical autocatalysis for diluted chemical reaction networks, J. Math. Biol. 85.

Nandan P., Nghe P., Stuyver T., Unterberger J. A parametrization of kinetics of organic chemistry reaction mechanisms, work in progress.

Parikh N., Boyd S. (2014). Proximal algorithms, Foundations and Trends in Optimization 1.

Robinson W. E., Daines E., van Duppen P., de Jong T., Huck W. T. S. (2022). Environmental conditions drive self-organization of reaction pathways in a prebiotic reaction network, Nature Chemistry 14.

Unterberger J. Optimal multi-time-scale estimates for diluted autocatalytic chemical networks (preprint).]]> Jeremie Unterberger Thèses hors de l'EDPIF Sat, 01 Feb 2025 11:17:17 +0100