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30
1
How tough is yogurt? Local viscoelastic properties of protein gels
Domaines
Condensed matter
Biophysics
Soft matter
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Type de stage
Expérimental Description
Colloidal gels are crucial in biological networks, cell mechanics, food science, and building materials. They result from the aggregation of sub-micron particles such as polysaccharide coils, actin filaments, attractive globular proteins, or cement particles, forming a percolated network that confers solid-like properties under small deformations. In addition, these gels display remarkable nonlinear behavior featuring stress- or strain-stiffening and fractures before irreversible rupture. Recent experiments have shown that the frozen-in stresses that develop during the sol-gel transition strongly impact the nonlinear response of these gels. However, these internal stresses were only evidenced indirectly at the macroscale. Moreover, there is no clear link between the microscale stress heterogeneities inside a colloidal gel and its macroscopic failure time.
The internship, which is part of the MICROFAT ANR project aims to link the frozen-in stresses at the microscopic scale and the gel nonlinear mechanical response at the macroscale. In practice, the candidate will measure the local mechanical properties of colloidal gels composed of proteins using atomic force microscopy and a state-of-the-art nano-indenter (CHIARO by Optics 11) to quantify the frozen-in stresses. Subsequent creep experiments conducted under a confocal microscope will allow the nonlinear gel response to be measured in regions of interest and link the frozen-in stresses with the failure scenario
Contact
Thibaut Divoux
Laboratoire : laboratoire de physique, ENS de Lyon - umr 5672
Equipe : ENS de Lyon, Physique
Site Web de l'équipe
Equipe : ENS de Lyon, Physique
Site Web de l'équipe
26/03/2024
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Thèse :
Rémunération :
2
Forme optimale pour la congélation d’un hydrogel
Domaines
Soft matter
Physics of liquids
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
Un hydrogel est composé d’une matrice de polymère pouvant contenir une quantité très importante d’eau. Bien que 99% de sa masse soit de l’eau, il conserve les propriétés d’un solide. En plaçant l’hydrogel sur un substrat de température inférieure à 0°C, celui-ci peut congeler. La nature solide de l’hydrogel permet de congeler des objets de différentes formes sans contenant et de créer toutes les formes possibles.
On se posera la question de la forme optimal à donner à cet objet pour qu'il congèle le plus rapidement possible. Une fois cette forme prédite théoriquement, on réalisera des expériences permettant de valider ce résultat.
Contact
Axel Huerre
Laboratoire : MSC - UMR 7057
Equipe : MSC: Dynamique des Systèmes Hors Equilibres.
Site Web de l'équipe
Equipe : MSC: Dynamique des Systèmes Hors Equilibres.
Site Web de l'équipe
25/01/2024
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Thèse :
Rémunération :
3
Electromagnetic simulations for near field GHz spectrometer
Domaines
Condensed matter
Topological materials, Quantum Transport, Cavity Quantum Electrodynamics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Théorique, numérique Description
The advances of circuit quantum electrodynamic (cQED) have enabled tremendous progress
both in the field of quantum computing and quantum sensors. It is now possible with such
circuits to detect accurately single photons in various range of frequencies, potentially
giving access to microscopic excitations in condensed matter systems.
However, the current tools are usually lacking spatiality and sensitivity. In that regard, in the
lab we are pursuing an endeavour to combine cQED methodology [1] with the latest
development in scanning probe techniques[2]. The idea would be to develop a scanning
nano-antenna to get access to single photon processes at the heart of condensed matter
systems with nanometer resolution.
The goal of this internship is to explore numerically different geometries of nano-antennas
and optimize the electromagnetic coupling with its environment at the relevant frequencies.
A first part of the internship will consist in designing and simulating this nano-antenna with
HFSS ANSYS. If time permits, you will be able to start the fabrication process by making
tips and on-chip antennas by state of the art lithography techniques. You will also participate
in the rest of the lab activities and discussion around the project.
The results of this internship will directly impact the design of future nanoantennas. It
requires creativity, rigor and a good understanding of classical electromagnetism.
Contact
Arthur Marguerite
12/01/2024
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Thèse :
Rémunération :
4
Active Adsorption of micro-algae at liquid-vapor interfaces using light
Domaines
Biophysics
Soft matter
Nonequilibrium statistical physics
Physics of living systems
Type de stage
Expérimental Contact
Raphaël Jeanneret
Laboratoire : LPENS - UMR8023
Equipe : Multiscale physics of biological systems
Site Web de l'équipe
Equipe : Multiscale physics of biological systems
Site Web de l'équipe
14/12/2023
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Thèse :
Rémunération :
5
Cloud microphysics and global warming
Domaines
Statistical physics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
Autumn 2023 smashed the previous global temperature record. It implies a strong acceleration of global warming, transient or not, for which the most likely explanation is a decrease of human-made aerosols as a result of reductions in China and from ship emissions. The aim of the internship and the PhD thesis is to investigate cloud physics, in connection to global warming issues, using a combination of experimental, theoretical and numerical work, from the nucleation of nanodrops to the organisation of clouds by convective aggregation.
Contact
Bruno Andreotti
20/11/2023
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Thèse :
Rémunération :
6
Exploring Combined Mathematical Techniques for Precise Computation of Resonance Properties
Domaines
Nuclear physics and Nuclear astrophysics
Type de stage
Théorique, numérique Description
The computation of resonance properties relies on various mathematical techniques, with a particular focus on the width of a state, representing the inverse of its half-life time ℏ. This width significantly influences the scattering amplitude in the proximity of the resonance energy and demands precise prediction. One method, complex scaling (CS), involves rotating momenta towards the complex plane, unveiling poles of the S-matrix. Similar momentum distortions to the complex plane are utilized by several others methods.
However, the use of a complex potential as a meta-model for absorption from the numerous other open channels induces a counteractive rotation of the S-matrix poles. This phenomenon raises the need to explore a combined approach integrating both techniques. The objectives of this internship encompass:
I. Investigating the synergy between complex scaling and complex potential to minimize the required CS rotation for discovering pole locations.
II. Analyzing the trajectory of the poles related to the imaginary component of the potential to understand their behavior.
III. Exploring the mathematical properties of the Jost function in the presence of a complex potential.
The internship aims to refine the computation of resonance properties and deepen our understanding of their mathematical underpinnings.
Contact
Guillaume Hupin
20/11/2023
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Thèse :
Rémunération :
7
Application of Eigenvalue Continuation method to the continuum.
Domaines
Nuclear physics and Nuclear astrophysics
Type de stage
Théorique, numérique Description
The Eigenvector Continuation (EC) method has emerged as a pivotal technique in nuclear structure analysis, standing as a standard tool for evaluating convergence properties within many-body methods. This method involves parameterizing the Hamiltonian to control its perturbative nature. In conjunction with considerations such as mesh size and other factors, numerical methods yield a finite set of results based on the parametrized input. These results encompass energies and eigenvectors expanded as Taylor series or Padé approximations, with coefficients tailored within a parameter range where the technique attains near-exactness.
A significant parallel exists between the EC workflow and methodologies in machine learning. Similar to the development of an AI algorithm, the EC approach necessitates using a training set to parameterize the algorithm before making predictions in uncharted regions beyond the training data. Despite encountering efficiency challenges in computing states across continua due to high-dimensionality, certain standard scattering techniques enable operations within a finite internal region.
These methodologies facilitate the application of EC to predict converged reaction observables. The primary aim of this project is to investigate the application of EC to a specific scattering solver, with a particular emphasis on integrating it with the No-Core Shell Model possessing continuum capabilities.
Contact
Guillaume Hupin
20/11/2023
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Thèse :
Rémunération :
8
Analog time reversal processor for radiofrequency signals
Domaines
Quantum optics/Atomic physics/Laser
Quantum information theory and quantum technologies
Type de stage
Expérimental Description
Time reversal is a technique based on the invariance of the wave propagation equation in an inhomogeneous medium. It ensures spatial and temporal refocusing of a wave after having recorded the transmission channel signature. When the propagation medium is non-stationary, the transmission channel characteristics keep changing. The time-reversed signal must be sent as quickly as possible, otherwise the refocusing will not be effective. In the first demonstrations of time-reversal with RF waves, analog-to-digital converters (ADC) were used, limiting the processing bandwidth. In the aim of reaching the GHz regime, the latency time becomes problematic because of the limited sampling rate of ADCs. Conversely, a fully analog solution has the advantage of avoiding this conversion step.
At Institut Langevin, we design original analog architectures for processing optically-carried radiofrequency signals based on light-matter interaction in rare-earth ion-doped crystals. In particular we recently proposed an architecture able to generate controlled, time-reversed copies of arbitrary waveforms. The goal of the internship will be to advance the development of this time-reversal processor, first using arbitrary signals and then using real RF signals reverberated in a cavity.
Contact
Anne Louchet-Chauvet
Laboratoire : Institut Langevin - UMR7587
Equipe : IL: NCIS (New Concepts for Imaging and Sensing)
Site Web de l'équipe
Equipe : IL: NCIS (New Concepts for Imaging and Sensing)
Site Web de l'équipe
15/11/2023
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Thèse :
Rémunération :
9
Surface tension vs elasticity gradient
Domaines
Soft matter
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Théorique, numérique Description
In this project, we will conduct Finite Elements Simulations of soft materials with a surface topography, surface stresses, and a gradient of surface elasticity. We will use the software COMSOL, and put emphasis on understanding the effect of elasticity gradient on surface mechanics. The results will be directly compared with existing experimental results
Contact
Nicolas Bain
13/11/2023
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Thèse :
Rémunération :
10
Deciphering mechanical homeostasis with FEM
Domaines
Biophysics
Soft matter
Physics of living systems
Type de stage
Théorique, numérique Description
In this project, we will conduct Finite Elements Simulations of local contractions inside homogeneous materials, and evaluate how stresses propagate as a function of material properties. We will use the software COMSOL, and put emphasis on understanding the link between material nonlinear properties and stress propagation. The results will be directly compared with ongoing experimental results.
Contact
Nicolas Bain
13/11/2023
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Thèse :
Rémunération :
11
Bruit du papier froissé
Domaines
Soft matter
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
L'objectif du stage est d'élucider le bruit sec et intense associé au froissement d'une feuille, d'un film ou d'une plaque, au cours duquel l'énergie élastique se concentre en déformations singulières (plis, cônes, etc...) qui évoluent et s'accompagnent souvent d'endommagement plastique. L’enjeu de la compréhension fine de ce phénomène est de déterminer dans quelle mesure la signature acoustique de ce type d’évènement élastique violent peut permettre d’en déterminer les causes (énergie libérée, type de singularité, localisation) mais aussi éventuellement les propriétés élastiques et dissipatives du matériau. Une première étape de ce stage sera de caractériser expérimentalement le rayonnement acoustique dans l’air d’ondes élastiques générées dans une plaque mince et de le confronter à la théorie du rayonnement. Des ondes d’amplitude finie seront ensuite employées pour caractériser le rayonnement de plaque dans un régime non-linéaire de déformation. Finalement, des défauts que l’on retrouve sur les films froissés seront créés et annihilés à la surface d’une plaque et le son résultant de leur formation ou de leur disparition sera enregistré et analysé grâce à la compréhension des études précédentes. Ces expériences pourront bénéficier au besoin de la chambre anéchoïque du laboratoire. Nous recherchons une étudiante ou un étudiant motivé par les expériences et les problématiques multiphysiques (acoustique, élasticité, singularités).
Contact
Régis Wunenburger
Laboratoire : Institut d'Alembert -
Equipe : Fluides Complexes et Instabilités Hydrodynamiques
Site Web de l'équipe
Equipe : Fluides Complexes et Instabilités Hydrodynamiques
Site Web de l'équipe
08/11/2023
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Thèse :
Rémunération :
12
Investigation of laser-produced magnetized collisionless shocks and associated particle acceleration
Domaines
Kinetic theory ; Diffusion ; Long-range interacting systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
Context:
Collisionless shocks are ubiquitous in the Universe. Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. With the development of high-power lasers and magnetic field generation, laboratory experiments can play a central role in bridging the gap between theoretical models and astrophysical observations by providing data that helps us to improve our understanding of shock formation, as well as the associated particle energization mechanism [1-3].
Proposed work:
The internship is part of an ongoing effort of investigating laser-produced collisionless shocks in a magnetic field of tens of Tesla, both experimentally with high-power lasers worldwide, e.g., LULI2000 (FR), VULCAN (UK), and TITAN (US); and numerically with fully kinetic particle-in-cell simulations performed with the code SMILEI [4].
Contact
Julien Fuchs
07/11/2023
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Thèse :
Rémunération :
13
Investigation of the laser cross-talk in a magnetized plasma
Domaines
Kinetic theory ; Diffusion ; Long-range interacting systems
Type de stage
Expérimental et théorique Description
Context:
Plasma is a non-linear medium [1], where light waves can couple to plasma waves. There exists a whole range of laser-plasma interaction (LPI) phenomena, from filamentation, stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), to cross-talk and braiding between laser beams [2] or cross-beam energy transfer (CBET) [3] between neighbor laser beams. Improving our knowledge of all these effects is not only important from a fundamental perspective, but also from a practical one in the frame of Inertial Confinement Fusion (ICF), where it is critical that as much as possible of the laser energy be transferred homogeneously to the fuel.
Proposed work:
The internship is part of an ongoing effort of investigating laser propagation and LPI in a magnetic field of tens of Tesla [4], both experimentally with high-power lasers worldwide, e.g., LULI2000 (FR) and TITAN (US); and numerically with fully kinetic particle-in-cell simulations performed with the code SMILEI [5] and magnetohydrodynamic (MHD) simulations with the code FLASH [6].
References:
[1] Turnbull, D., et al., PRL 118, 015001 (2017).
[2] Nakatsutsumi, M., et al., Nat. Phys. 6, 1010 (2010).
[3] Michel, P., et al. Phys. Plas. 17, 056305 (2010).
[4] Yao, W., et al. PRL 130, 265101 (2023).
[5] Derouillat, J., et al., Comput. Phys. Commun. 222, 351-373 (2018)
[6] Fryxell, B., et al. The Astrophysical Journal Supplement Series 131.1, 273 (2000)
Contact
Julien Fuchs
07/11/2023
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Thèse :
Rémunération :
14
Collective effects in fish
Domaines
Biophysics
Physics of liquids
Physics of living systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Théorique, numérique Description
The collective behavior of fish is an astonishing example of coordinated movement that forms spontaneously on a large scale despite limited communication between individuals. In situ studies have identified the benefit of such schooling behavior: energy saving for swimming, visual effect for fighting a predator. Recently, experimental studies have also made it possible to test interaction models between individuals in a simple environment. Some phases of collective movements have been characterized by different dynamic models of non-equilibrium systems. We have recently proposed a model, purely orientational, which shows the gain in rheotaxis performance in the presence of collective interactions. For this internship, we propose a numerical work. The objective of the internship is to study the dynamics of groups of fish in 3D. A preliminary work has already been carried out and shows the emergence of new phases that appear and do not exist in 2D (i.e. the majority of models published in the literature) like elongated milling structures or turning phases that appear because of the third dimension. A phenomenon that has to be understood!
Contact
Aurélie Dupont
07/11/2023
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Thèse :
Rémunération :
15
Challenging collective behavior of fish: evacuation through two doors
Domaines
Biophysics
Physics of living systems
Non-equilibrium Statistical Physics
Type de stage
Expérimental Description
The collective behavior of fish is an astonishing example of coordinated movement that emerges spontaneously on a large scale despite limited communication between individuals. Recently, we have challenged the collective behavior of fish by forcing the fish school to pass through a bottleneck. This experiment revealed that, unlike humans, fish still respect social distance upon emergency evacuation which renders the evacuation more efficient. To go further and reveal cognitive effects, we want to repeat the evacuation experiments but with two openings. By varying the opening size and the distance between them, we aim at characterizing the gregarious instinct of fish.
Contact
Aurélie Dupont
07/11/2023
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Thèse :
Rémunération :
16
Swimming in fluctuating lanes: How do bacteria navigate changing environments?
Domaines
Condensed matter
Statistical physics
Biophysics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Physics of living systems
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Théorique, numérique Description
Microorganisms, such as bacteria or microalgae, are often found in complex environments: from maze-like structures in soils to serpentine channels in the intestine. Numerous works have characterized the motion of microorganisms in the bulk. However, studies in realistic environments remain scarce. Recently [1], it was found that bacteria in porous media (a microscale maze-like 3D structure) exhibit a peculiar behavior and get trapped in specific spots. This is due to the time to flip their swimming direction.
In addition, in Nature, environments dramatically evolve in time, from rainfalls which induce flows to soil mazes that continuously reorganize due to the presence of other microorganisms which create jams or open up pathways.
Toinvestigate the motion of microorganisms in such fluctuating environments, we will explore a minimal model of active particles moving through a wiggling channel (=swimming in a fluctuating lane). We will study the diffusion and the drift of the particles according to the speed of the fluctuations [2]. We expect to uncover interesting regimes where motion is increased by collisions with the channel walls. We also expect odd behaviors associated with the interplay between different time scales in the system. We will characterize these different regimes. This internship will be in collaboration with Ruben Zakine (Ecole Polytechnique).
Contact
Sophie Marbach
06/11/2023
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Thèse :
Rémunération :
17
Counting Bacteria in Boxes: How do bacteria colonize surfaces?
Domaines
Condensed matter
Statistical physics
Biophysics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Physics of living systems
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
The colonization of surfaces by bacteria raises many societal issues related to antibiotic resistance and waste management. Our grasp on initial surface establishment, crucial to address colonization at its roots, is limited. In this early stage, bacteria number fluctuations – due to surface adhesion, division, or motility – are large, challenging current analysis tools and theories. These fluctuations can result in more tight or sparse aggregates, dramatically affecting long-term colonization dynamics. How do individual dynamics and intermittent adhesion determine these aggregate patterns and collective growth?
To make progress, we will use a new analysis technique relying on number fluctuations called the ``Countoscope’’ [2]. The principle is like a game! We count the number N(t) of particles (bacteria, colloids or cells) in analysis boxes over time. The number of particles in a box fluctuates due to microscopic dynamics such as diffusion, adhesion, etc. Interpreting N(t) requires building new theories in this colonization context. These theories can then disentangle processes and quantify dynamics from the time-dependent statistics of N(t).
Here we will, on the one hand, count the number of bacteria in various box sizes on experimental images. On the other hand, we will develop minimal models to interpret these counts. This internship will be in collaboration with Eleonora Secchi (Zurich), who investigates bacteria on surfaces in microfluidic channels.
Contact
Sophie Marbach
06/11/2023
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Thèse :
Rémunération :
18
Micromanipulation study of RNA energy landscape modulation by epigenetics
Domaines
Statistical physics
Biophysics
Soft matter
Physics of living systems
Type de stage
Expérimental Description
Magnetic tweezers are a tool enabling real-time monitoring of nucleic acid extension on a single-molecule scale, at several hundred Hz. They are perfectly suited for tracking the temporal evolution between different molecular conformations of nucleic acids and measuring their energy differences as we already demonstrated. What's more, by imposing a tensile force on the molecules studied, it is possible to modify the energy profile and bring out minority conformations, i.e., those of higher energy.
The proposed project will first study of the influence of methylation on RNA conformational flexibility at the single molecule level with magnetic tweezers. After the quantification of the conformational energy profile of the RNA, the influence of RNA methylation on protein binding on the sequence used will be investigated.
Contact
Jean Francois Allemand
Laboratoire : LPENS - UMR8023
Equipe : Multiscale physics of biological systems
Site Web de l'équipe
Equipe : Multiscale physics of biological systems
Site Web de l'équipe
06/11/2023
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Thèse :
Rémunération :
19
Coherent quantum emitter coupled to a nanophotonic waveguide
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Quantum optics
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental Description
Photons have long been favored as carriers of information due to their non-interacting nature. Tradition- ally, atoms have served as the primary means to manipulate and process quantum information carried by photonic qubits. However, recent groundbreaking advancements in solid-state emitters such as color centers, quantum dots, and molecules have ushered in a new era of highly coherent interaction with light, akin to atomic-level interactions.
Moreover, the seamless integration of solid-state emitters into nanophotonic structures has unlocked the potential for achieving remarkably efficient light-matter interactions [1]. Amongst them, nanofibers have attracted attention due to their guided evanescent field that enables efficient coupling of emitters placed at their vicinity. This breakthrough not only facilitates the creation of high-performance single- photon sources but also enables the exciting prospect of photon-photon interactions[2].
Within the nanophotonic research team at LKB, we have cultivated expertise in the production of nanofiber waveguides and their precise coupling with solid-state emitters [3, 4]. This specialized focus empowers us to drive advances in single-photon quantum information processing
Contact
Quentin Glorieux
31/10/2023
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Thèse :
Rémunération :
20
The hidden mechanics of soft gels
Domaines
Soft matter
Type de stage
Théorique, numérique Description
Gels constitute a large portion of the materials around us: body tissues, food products, but also industrial glues and seals. At first glance, they are mechanically similar to other elastic materials. If you take a piece of gelatin, for instance, you can deform it by a small amount and it will return to its original shape. If you look closer, however, gels have a complex molecular structure. They are made of a crosslinked polymeric network swollen by a liquid solvent. As a consequence, their mechanical behavior is dictated by the coupling between the elastic deformations of the polymeric network and the flow of the solvent. For simplicity, they are often modeled as incompressible solids, and these models are then used to estimate, for instance, adhesion forces of cells living on soft tissues. Whether they truly behave as incompressible solids, however, is both difficult to asses and crucial for an accurate modeling. In this project, we will take a deep dive into gel mechanics. You will exploit recently collected experimental data, which tracks the 3D displacement of the polymeric network inside a silicone gel, to understand in which circumstances a gel can be modeled as an incompressible solid. This will involve numerically analyzing of the displacement of tens of thousands of tracers, and rationalizing the results within the framework of continuum mechanics. The results will be directly compared with existing numerical predictions.
Contact
Nicolas Bain
24/10/2023
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Thèse :
Rémunération :
21
Quantum imaging with non-degenerated entangled photons
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Non-relativistic quantum field theory, quantum optics, complex quantum systems
Quantum information theory and quantum technologies
Quantum optics
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Metrology
Type de stage
Expérimental Description
Quantum imaging (QI) is a rapidly developing field of research with stunning progresses and emerging societal applications. Quantum-enhanced imaging schemes harness the beneficial properties of entangled photon pairs allowing transferring amplitude and phase information from one photon state to the other. The technique is however still in its infancy and we propose to go beyond the state of the art. The main goal is to develop advanced QI protocols that exploits photon pairs at extreme wavelengths from near infrared to the visible down to the deep UV using a non-classical source based on high harmonic generation (HHG). The main objective of the internship will consist in using a pair of non-degenerated entangled photons at 2 harmonics from the HHG frequency comb to perform a quantum imaging experiment in the far field regime. We will study the possibility of transferring the sensing and resolution benefit from one spectral range to another one. Indeed, an intriguing question is about the spatial resolution achievable in the QI scheme, especially in the case of non-degenerate photon pairs. The quantum correlations between the two photons from the same harmonic generation process will be used to transfer amplitude and phase information between the two photons. In the diffractive regime, and in a "ghost diffractive imaging" configuration based on the coincident detection of the two entangled photons.
Contact
Hamed Merdji
Laboratoire : LOA - UMR 7639
Equipe : Ultrafast sources of Particles and X rays (UPX)
Site Web de l'équipe
Equipe : Ultrafast sources of Particles and X rays (UPX)
Site Web de l'équipe
24/10/2023
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Thèse :
Rémunération :
22
Evidence of multipartite entanglement in semiconductor high harmonic generation
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Nouveaux états électroniques de la matière corrélée
Non-relativistic quantum field theory, quantum optics, complex quantum systems
Quantum information theory and quantum technologies
Quantum optics
Topological materials, Quantum Transport, Cavity Quantum Electrodynamics
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Metrology
Type de stage
Expérimental Description
Quantum information science and imaging technologies reach some bottleneck due to limited scalability of non-classical sources. Future breakthroughs will rely on high production rate of various quantum states in scalable platforms. Generally, multipartite entanglement with N>2 suitable for quantum applications is difficult to achieve because of the low efficiency of the traditional schemes. Intrinsically, the HHG emission comes as a frequency comb and should exhibit N-partite entangled photons. Practically, the internship project will consist in extensively study the non-classical properties of the HHG process in a semiconductor for N>2. In the process, each emitted photon is a superposition of all frequencies in the spectrum, i.e., each photon is a comb so that each frequency component can be bunched and squeezed. The candidate will first develop and test entanglement and quantum correlations using the violation of Cauchy-Schwartz inequality. We will verify genuine multipartite entanglement of the photons in the time/frequency domain, by correspondingly measuring the longitudinal position as well as the frequency bandwidth. The approach will be further extended to verify multi-partite entanglement between even more optical modes. The Bell-like inequalities will therefore be generalized to witness entanglement between more than three mixed quantum states.
Contact
Hamed Merdji
Laboratoire : LOA - UMR 7639
Equipe : Ultrafast sources of Particles and X rays (UPX)
Site Web de l'équipe
Equipe : Ultrafast sources of Particles and X rays (UPX)
Site Web de l'équipe
24/10/2023
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Thèse :
Rémunération :
23
Attosecond control of quantum states of light
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Non-relativistic quantum field theory, quantum optics, complex quantum systems
Quantum information theory and quantum technologies
Quantum optics
Topological materials, Quantum Transport, Cavity Quantum Electrodynamics
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental Description
High-harmonic generation is a light up-conversion process occurring in a strong laser field, leading to coherent attosecond bursts of extreme broadband radiation. As a new paradigm, attosecond electronic or photonic processes such as high-harmonic generation (HHG) can potentially generate non-classical states of light well before the decoherence of the system occurs. This could address fundamental challenges in quantum technology such as scalability, decoherence or the generation of massively entangled states with ultrafast processing. The internship will consist in realizing a platform that will allow controlling the carrier to envelope phase (CEP) of the laser that drives the semiconductor HHG emission. The CEP of the laser will allow controlling the non-classical state, in connection with our recent finding in various semiconductors (Theidel et al, submitted to Nature, in review). Single and multi-beam intensity cross-correlation, two-mode squeezing in the generated harmonic radiation, which depends on the laser intensity will be investigated. We will test the violation of the Cauchy-Schwarz inequality that realizes a direct test of multipartite entanglement in high-harmonic generation. The attosecond control of light states open the vision of quantum processing on unprecedented timescales, an evident perspective for future quantum optical computers. Only candidates motivated to follow with a PhD in this topic will be considered.
Contact
Hamed Merdji
Laboratoire : LOA - UMR 7639
Equipe : Ultrafast sources of Particles and X rays (UPX)
Site Web de l'équipe
Equipe : Ultrafast sources of Particles and X rays (UPX)
Site Web de l'équipe
24/10/2023
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Thèse :
Rémunération :
24
Nanoscale Patterns and Dynamics of Evaporation/Condensation of Salty Water
Domaines
Condensed matter
Statistical physics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Hydrodynamics/Turbulence/Fluid mechanics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental et théorique Description
Salty water is everywhere (oceans, underground, and even in the atmosphere). The way it reacts to humidity changes is important in many natural, societal and technological contexts (water harvesting, cultural heritage preservation, geophysics, civil engineering, aerosol and cloud formation, energy conversion, etc.). We follow parallel research investigations (with experiments, theory and/or numerical simulations) to elucidate how surfaces, nanoscale confinement and disorder, which can be found in many of these contexts, dictate the dynamics and patterns that emerge from transport and/or phase change of salt solutions.
Contact
Olivier Vincent
19/10/2023
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Thèse :
Rémunération :
25
Trees drying from the inside: physics of bubble propagation
Domaines
Condensed matter
Statistical physics
Biophysics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Physics of living systems
Non-equilibrium Statistical Physics
Hydrodynamics/Turbulence/Fluid mechanics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental et théorique Description
Numerical simulations and/or experimental investigations of patterns and dynamics related to bubble nucleation, growth and propagation in complex vascular networks inspired by trees. The general context is understanding how trees (plants in general) respond to humidity changes, and in particular drought events that are becoming more frequent. This remains a topic in physics, with external collaboration with plant physiologists.
Contact
Olivier Vincent
19/10/2023
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Thèse :
Rémunération :
26
Dynamique et statistique de lancers de dés 2d
Domaines
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Type de stage
Expérimental Description
[Français] La dynamique d’un dé (ou de n’importe quel polyèdre) tombant sur une surface est constitué d’une alternance
complexe de mouvements réguliers et de chocs dissipatifs, dont il est difficile de dégager des propriétés moyennes.
En particulier si les faces du dé ont des aires différentes, la répartition statistique des configurations finales n’est
à l’heure actuelle pas comprise.
L’objectif de ce stage de recherche en laboratoire sera d’étudier la dynamique de chute d’un ‘dé’ bidimension-
nel (confiné entre deux plaques) et de faire le lien avec la répartition statistique d’un grand nombre de lancers.
Selon l'affinité de l'étudiant·e, les expériences pourront être complétées par de la modélisation et/ou une étude numérique.
[English] Although the dynamics of a die (or any polyhedron) falling onto a surface involves only basic mechanics (rigid
body, rebounds, sliding), its complex out-of-equilibrium dynamics makes predicting statistical behaviour far
from obvious. In particular, if the faces of the die have different areas, the statistical distribution of the
results obtained is not currently understood.
The aim of this laboratory research internship will be to examine the fall of a two-dimensional ‘die’ (confined
between two plates) and to make the link with the statistics of the final state. While our first aim will be to gather experimental data, interested students may well add some theoretical modeling and/or numerical simulations.
Contact
Adrian Daerr
Laboratoire : MSC - UMR 7057
Equipe : MSC: Dynamique des Systèmes Hors Equilibres.
Site Web de l'équipe
Equipe : MSC: Dynamique des Systèmes Hors Equilibres.
Site Web de l'équipe
19/10/2023
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Thèse :
Rémunération :
27
Multiscale Dynamics in bacterial populations
Domaines
Condensed matter
Statistical physics
Biophysics
Soft matter
Physics of living systems
Non-equilibrium Statistical Physics
Type de stage
Expérimental et théorique Description
Bacteria are one the most fundamental and abundant forms of life on Earth. For human health, they represent both a threat, with the emergence of massive multi-resistance to antibiotics, and an opportunity, as the microbiota can positively influence human physiology. The bacterial strains currently studied in research laboratories are very easy to grow and maintain, making them a highly convenient experimental system for studies at both single-cell and population levels. Our lab seeks to understand how the different scales are coupled: from protein dynamics to colony organization. To do this, we use live microscopy and image analysis to capture and model the observed spatial and temporal dynamics.
Contact
Nicolas Desprat
Laboratoire : LPENS - UMR8023
Equipe : Multiscale physics of biological systems
Site Web de l'équipe
Equipe : Multiscale physics of biological systems
Site Web de l'équipe
18/10/2023
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Thèse :
Rémunération :
28
High Energy Gamma-Ray Astronomy (neutron stars, black holes)
Domaines
High energy physics
Relativity/Astrophysics/Cosmology
Type de stage
Expérimental Description
The proposed project is a deep follow-up study on the gamma-ray binary LS I +61 303 at GeV energies. It is one of the best studied binary systems at high energies showing a very particular behavior: On top of the orbital period of about one month, it shows a super-orbital modulation of about 4 years in several wavelengths.
Since the discovery of this phenomenon at GeV energies, the dataset taken by the satellite Fermi has doubled. We propose to analyze the latest Fermi-LAT dataset on the source, prove or falsify the findings done 10 years ago and perform a deep study on the orbital behavior of the source. These findings will be of great interest for the community.
Contact
Michel Gonin
14/10/2023
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Thèse :
Rémunération :
29
How to maintain the two essential functions of insects in a changing climate? Microrheology and chemistry of cuticular hydrocarbons in ants
Domaines
Biophysics
Type de stage
Expérimental Description
In this project, we will study the relationship between the rheology and chemical composition of cuticular hydrocarbons in ants, under acclimatisation conditions. This exciting project, which spans physics, chemistry and biology, takes place at Laboratoire Matière et Systèmes Complexes (MSC), located in Paris 13e. It will be carried out in international and interdisciplinary collaboration with the Institute of Organic and Molecular Evolution. A short-term internship at the University of Mainz (Germany), for chemical and behavioural analyses, is possible.
Contact
Berengere ABOU
Laboratoire : MSC - UMR 7057
Equipe : MSC: Dynamique des Systèmes Hors Equilibres.
Site Web de l'équipe
Equipe : MSC: Dynamique des Systèmes Hors Equilibres.
Site Web de l'équipe
09/10/2023
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Thèse :
Rémunération :
30
Growth and spintronics of low symmetry magnetic layers
Domaines
Condensed matter
Type de stage
Expérimental et théorique Description
The goal of this internship is to realize ultrathin films of metallic and magnetic layers on insulating substrates of very low symmetry. The samples will be made in the clean room of the Matériaux et Phénomènes Quantiques lab in Paris and characterized by x-ray diffraction and vibrating sample magnetometry or magneto-optical effects for their magnetic properties. The second part of the internship will be to achieve lithography and electronic transport measurements on those samples for magnetic memory applications. This part will be done in part in Singapore, in collaboration with Pr. Yang's group, at the Computer and Electrical Engineering departement of the National University of Singapore.
Contact
Vincent Repain
09/10/2023
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Thèse :
Rémunération :