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Nombre d'offres
31
1
Air film dynamics
Domaines
Condensed matter
Biophysics
Soft matter
Physics of liquids
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Théorique, numérique Description
Air film dynamics -
Context: Gas transfer at the ocean surface has a critical importance for climate, as it captures around 30% of the CO2 released into the atmosphere, and for marine biological activity, as it provides the necessary O2. This transfer can be promoted by the entrapment of bubbles, produced through impacting rain drops or breaking waves. The shape and dynamics of the bubbles are important to model these transfers.
Goals: We propose in this project to study the contraction dynamics of an air film into a fluid. We will systematically vary the gas and fluid properties in different geometries to understand their contraction velocity and rupture mechanisms. This project will combine numerical simulations (using the open-source code Basilisk) with theoretical analysis to uncover the physical processes involved in the gas transfer into the ocean.
Profile: Candidates should have a good training in Fluid Mechanics and Computational Fluid Dynamics.
Environment: The project will take place in the laboratory of Prof. Marie-Jean THORAVAL at LadHyX in École Polytechnique, in the South of Paris.
Contact
Marie-Jean THORAVAL
12/11/2024
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Thèse :
Rémunération :
2
Impact of compound drops: Bouncing or Sticky?
Domaines
Condensed matter
Biophysics
Soft matter
Physics of liquids
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
Impact of compound drops: Bouncing or Sticky? -
Context: The impact of a drop onto a solid or liquid surface has a wide range of applications including combustion, 3D printing, biological microarrays, pharmaceutics and the food industry. While most of them rely on single fluid drops, the emergence of new additive manufacturing techniques promises to revolutionize these industries by combining multiple fluids into compound drops. One of the critical challenges in these applications is to control the deposition process of the impacting drop and therefore its spreading, potential rebound and splashing.
Goals: We propose in this project to control the rebound of the water core by varying the viscosity and thickness of the outer oil layer. We will combine high-speed imaging experiments with high resolution numerical simulations (using the open-source code Basilisk) to investigate these complex dynamics, and uncover the physical processes involved in the deposition of compound drops.
Profile: Candidates should have a good training in Fluid Mechanics. The project can either be focused on experimental observations and/or numerical simulations depending on the applicant.
Environment: The project will take place in the laboratory of Professor Marie-Jean THORAVAL at LadHyX in École Polytechnique, in the South of Paris.
Contact
Marie-Jean THORAVAL
12/11/2024
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Thèse :
Rémunération :
3
Drop impact on a pool of immiscible liquid
Domaines
Condensed matter
Biophysics
Soft matter
Physics of liquids
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Théorique, numérique Description
Drop impact on a pool of immiscible liquid
Context: The impact of a liquid drop onto a liquid surface is a commonly observed phenomenon in nature and throughout daily life, and is important for many industrial processes such as spray painting, inkjet printing and spreading of pesticides. It has been demonstrated recently that this process could be used for the mass production of particles with complex shapes and cell encapsulation [1]. The geometry of the resulting particles strongly depends on the impact dynamics and the deformation of the interfaces.
Goals: In this project, we propose to investigate the formation of complex encapsulations formed by the impact of a liquid drop on a pool of immiscible liquid. We will systematically study the impact of water drops on a pool of an immiscible liquid such as silicone oil. We will combine high-speed imaging experiments with high resolution numerical simulations (using the open-source code Basilisk) to investigate these complex dynamics, and uncover the physical processes involved.
Profile: Candidates should have a good training in Fluid Mechanics. The project can either be focused on experimental observations and/or numerical simulations depending on the applicant.
Environment: The project will take place in the laboratory of Prof. Marie-Jean THORAVAL at LadHyX in École Polytechnique, in the South of Paris.
Contact
Marie-Jean THORAVAL
12/11/2024
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Thèse :
Rémunération :
4
Sedimentation of diatom chain colonies
Domaines
Biophysics
Soft matter
Physics of liquids
Physics of living systems
Type de stage
Théorique, numérique Description
Diatom chains are cohesive assemblies of unicellular microorganisms that are found in still and fresh waters. Some species are passively transported by ambient currents and settle due to the weight of their dense silica shells, while others have use various strategies to move or self-propel. One species in particular, called Bacillaria Paxillifer, forms colonies of stacked rectangular cells that slide along each other while remaining parallel. As observed in experiments, and reproduced by our numerical model, their intriguing coordinated motion, leads to beautiful and nontrivial trajectories at the scale of the colony. However, the effect of gravity and external flows on the dynamics of diatom chains must be investigated to understand the behavior of plankton and marine snow aggregates as they sink, and capture CO2, to the ocean depths...
Contact
Blaise Delmotte
12/11/2024
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Thèse :
Rémunération :
5
Quantum dot fluorescence and optomechanical coupling
Domaines
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental Description
The emission of colloidal quantum dots is highly dependent on their environment. Placed between two layers of gold, and excited in UV light, their emission couples with surface plasmons and its dynamics is accelerated. The smaller the gap between the two gold layers, the more the emission is modified. We propose to actively modify the spacing between the two layers in order to modify quantum dot emission.
We will use the transient grating method, which involves exciting the sample with two infrared laser beams (exc =1064nm; 30ps pulse duration) to produce interference bangs with a period . Through photoelasticity, the standing waves thus created cause the sample to vibrate, modulating its thickness.
The aim of the internship will be to study how the acoustic wave thus created modifies the properties of the light emitted.
The first step will be to produce the samples. After depositing an optically thick layer of gold on a glass subtrate, a solution of CdSe/CdS quantum dots will be deposited. This emitter layer is then covered by a thin layer of gold. Secondly, this layer will be optically characterized under a microscope, both to characterize its thickness in white light and the fluorescence of the quantum dots under UV illumination. Finally, we'll use the transient grating method to change the thickness of the sample. Both thickness and quantum dot fluorescence will be studied.
Contact
Agnes MAITRE
07/11/2024
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Thèse :
Rémunération :
6
Temperature-controlled plasmonic nano-antennas
Domaines
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental Description
Already around 15 years ago, it has been shown that liquid crystal topological defects can be used to confine and organize nanoparticles. In particular, oriented chains of nanospheres or of tip-to-tip nanorods have been formed in unidimensional smectic defects, dislocations and disclinations (Fig.1) [1]. The liquid crystal phase transitions occurring at low temperature, liquid crystals can provide temperature-activated assemblies of nanoparticles [2]. In this context, we propose to use oriented unidimensional smectic defects in order to build plasmonic nanoantennas based on strictly facing gold nanorods in close contact. We will study the evolution of the light absorption of the nanoantennas when temperature is increased in relation with the disappearing of the liquid crystal defects driven by the liquid crystal phase transition. This study will pave the way for an activation of the coupling strength between nanoparticles actively tuned by the temperature. This would be a first step towards future optical devices based on visual appearance controlled by varying temperature.
[1] S.P. Do et al. Nano Letters 20 (2020) 1598, [2] H. Jeridi, Appl. Phys. Lett. 123 (2023) 203101
Contact
Emmanuelle Lacaze
Laboratoire : Institut des NanoSciences de Paris - UMR 7588
Equipe : Chemical Physics and Dynamics of Surfaces
Site Web de l'équipe
Equipe : Chemical Physics and Dynamics of Surfaces
Site Web de l'équipe
06/11/2024
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Thèse :
Rémunération :
7
Understanding the causes of uterine hypercontractility in endometriosis
Domaines
Biophysics
Physics of living systems
Type de stage
Expérimental et théorique Description
Endometriosis is a pathology affecting 6-10% of the female population, characterized by the implantation of uterine endometrial nodules either in the body of the uterus (known as adenomyosis) or ectopically, on various organs in contact with the peritoneal cavity such as the bladder, intestines, Fallopian tubes etc. This pathology results in severe pain during menstruation and can lead to infertility. Endometriosis and adenomyosis are associated with hypercontractility of the myometrium, the uterine smooth muscle. The cause of hypercontractility in endometriosis is currently not known, and could be a major player in disease pathogenesis, treatment and prevention. The goal of our project is to understand whether hypercontractility can result from a structural alteration of the architecture of the uterine wall, for example of the smooth muscle, of its innervation, or its hormone receptor distribution. This internship focuses on the quantitative analysis of histological images of the uterine muscle by machine learning techniques.
Contact
Nicolas Chevalier
Laboratoire : MSC - UMR7057
Equipe : Morphogenèse et Dynamique des Systèmes Auto-Organisés
Site Web de l'équipe
Equipe : Morphogenèse et Dynamique des Systèmes Auto-Organisés
Site Web de l'équipe
06/11/2024
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Thèse :
Rémunération :
8
Thermal avalanches and depinning transition of a contact line
Domaines
Statistical physics
Physics of liquids
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental Description
Thermal avalanches serve as a unifying mechanism for heterogeneous flows in disordered materials and glassy systems. The dynamical heterogeneities in these materials, which reflect the interplay between endogenous mechanical noise and exogenous thermal noise, have primarily been studied theoretically in the context of creep flows of pinned elastic manifolds and in simulations of super-cooled liquids, with the notable exception of the logarithmic aging of crumpled sheets. The aim of the internship and the PhD thesis is to investigate the effect of finite temperature on the depinning transition of a contact line, utilizing a combination of controlled laboratory experiments, theoretical analysis, and numerical simulations.
Contact
Kristina Davitt
06/11/2024
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Thèse :
Rémunération :
9
Eigenvector Continuation in Nuclear Ab Initio Methods
Domaines
Nuclear physics and Nuclear astrophysics
Type de stage
Théorique, numérique Description
Eigenvector Continuation (EC) is based on the idea of leveraging the information contained in a small number of known solutions (eigenvectors) of a system's Hamiltonian to predict the solutions in a broader parameter space. This approach is especially useful when dealing with systems where exact solutions are difficult or computationally expensive to obtain. In this project, we will apply EC to ab initio nuclear many-body calculations using the no-core shell model with continuum (NCSMC) approach, which aims to predict nuclear structure and reactions directly from fundamental forces and provide a unified treatment of a wide range of nuclear phenomena (bound and unbound states, scattering and reaction observables). EC can significantly reduce the computational cost by narrowing down the necessary subspace for solving the many-body Schrödinger equation. Additionally, EC provides an efficient framework for exploring the effects of varying parameters, thereby improving the accuracy of uncertainty estimates in nuclear theory predictions.
Contact
Guillaume Hupin
06/11/2024
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Thèse :
Rémunération :
10
Developing charge-tunable coupled quantum dot devices for quantum computation
Domaines
Condensed matter
Quantum information theory and quantum technologies
Quantum optics
Type de stage
Expérimental Description
In this internship we will fabricate coupled quantum dots, where the two dots are close enough that carriers can tunnel coherently between them. We will do this using molecular beam epitaxy, a thin-film growth technique, which allows precise control of layer thicknesses and composition. These dots will be embedded in diode structures allowing a field to applied across the dots, bringing their energy levels into resonance to create delocalised electronic states. The student will have the opportunity to participate in all the stages of development of a new
quantum device: from device design, thin film growth and device fabrication to the low
temperature photoluminescence measurements of quantum confinement effects.
Contact
Paola Atkinson
04/11/2024
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Thèse :
Rémunération :
11
Improving stochastic simulations of complex chemical systems with bitwise arithmetic
Domaines
Statistical physics
Biophysics
Physics of living systems
Type de stage
Théorique, numérique Description
The Gillespie algorithm is a powerful computational tool to simulate the dynamics of a system of interacting chemical species in regimes where particle numbers are small, and stochastic fluctuations are large. This well-known algorithm becomes computationally demanding when one attempts to sample a large number of configurations, e.g. looking for rare samples in the dynamics, or simulating a large number of species or reactions. We propose to develop a new method to increase the computational yield of the algorithm, by leveraging the boolean representation of particle numbers as they are stored in a computer.
Different applications of the algorithm will be explored in the context of simulating complex chemical systems, which are typically non-well mixed and contains a large number of species and reactions.
The student will be tasked with the numerical implementation of this parallel Gillespie algorithm, and with its application to a few representative models of interacting chemical species.
The student will acquire valuable interdisciplinary skills, such as proficiency in C++, and getting familiar with models of chemical-reaction networks.
Contact
Michele Castellana
Laboratoire : PCC, Institut Curie - UMR168
Equipe : Dynamic Control of Signaling and Gene Expression
Site Web de l'équipe
Equipe : Dynamic Control of Signaling and Gene Expression
Site Web de l'équipe
02/11/2024
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Thèse :
Rémunération :
12
Watching interfacial charge dynamics following liquid and solid triboelectrification
Domaines
Condensed matter
Soft matter
Physics of liquids
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental Description
Triboelectric charging - the process by which dielectric surfaces can acquire a net charge when rubbed together - represents a fundamentally misunderstood process in physics, with both fundamental and mundane consequences. The idea of this internship is to focus on the particular case of liquid triboelectrification, whereby water drops sliding on hydrophobic surfaces leads to a macroscopic separation of charges. In particular, we will employ recently developped surface charge mapping strategies to probe the peculiar dynamics of the ions trapped at the solid/gaz interface following liquid tribocharging.
Contact
Jean Comtet
Laboratoire : Sciences et Ingénierie de la Matière Molle - UMR7615
Equipe : SIMM
Site Web de l'équipe
Equipe : SIMM
Site Web de l'équipe
30/10/2024
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Thèse :
Rémunération :
13
Flows and shapes of membrane with a protein inclusion
Domaines
Biophysics
Soft matter
Physics of liquids
Physics of living systems
Type de stage
Théorique, numérique Description
Many cellular functions rely on the ability of cells to alter their shape. At the cell-membrane level, shape changes are driven by forces which, regulated by specific proteins, alter the membrane curvature through structural alterations. We will study theoretically the fluid mechanics of a cell membrane—modelled as a two-dimensional fluid layer—including a trans-membrane protein.
In the absence of flows, the membrane shape is determined by a balance between Laplace pressure and bending rigidity. The presence of flows in the membrane fluid alters this picture: viscous forces stemming from the flow alter the membrane shape. This intertwinement between flows and shape may reveal novel, physical features, which we plan to study.
The strong points of this internship are:
Scientific publications will be aimed at the best scientific journals
The student will acquire valuable skills, such as proficiency in Python, learning and mastering of the finite-element method, and others, which will be highly beneficial for his/her future scientific career.
- The cross-disciplinary character of this internship, bridging between theoretical physics, differential geometry, experimental physics and biology, will offer numerous directions for future developments of the project.
See https://sites.google.com/site/michelecastellana/internship-proposals for more details.
Contact
Michele Castellana
Laboratoire : PCC, Institut Curie - UMR168
Equipe : Dynamic Control of Signaling and Gene Expression
Site Web de l'équipe
Equipe : Dynamic Control of Signaling and Gene Expression
Site Web de l'équipe
28/10/2024
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Thèse :
Rémunération :
14
Clustering of particles floating on a vibrated liquid surface
Domaines
Statistical physics
Physics of liquids
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
When several particles float on the surface of a liquid, they tend to cluster together. This phenomenon results from capillary attraction, sometimes called "Cheerios effect". In this project, we aim to study what happens to a cluster of floating particles in the presence of capillary waves in the Faraday geometry (thin liquid layer subjected to vertical vibration). The vertical oscillation can trigger standing waves on the surface, known as Faraday waves, which will interact with the particles.
The first goal of the project is to experimentally explore the behavior of a large number of spheres under capillary interaction and for varying vibration amplitudes. Depending on the surface density of the spheres and the vibration amplitude, we expect collective behavior similar to that of gas (dilute medium with disordered movements), liquid (denser medium with highly correlated movements), or solid (very dense medium with crystalline order and defects).
The existence of these different phases is very common for interacting particles. The question is whether Faraday waves play a role similar to temperature. In a second phase, the floating spheres will be replaced with particles of more complex shapes, such as elongated particles that may exhibit local alignment properties, in order to study the influence of this local order on aggregation properties.
Contact
Frederic Moisy
22/10/2024
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Thèse :
Rémunération :
15
How salt-infused nanosponges respond to humidity changes
Domaines
Condensed matter
Statistical physics
Soft matter
Physics of liquids
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
We are interested in fundamental physics problems that are relevant in various important societal and engineering contexts. In particular, we study how evaporation and condensation of salty water happens in complex systems, triggered by variations in external humidity. These phenomena are crucial for e.g. water harvesting in dry climates, cloud formation in the atmosphere, new strategies for energy production/conversion, smart optical/mechanical metamaterials, sustainable architecture and heritage conservation, etc. but raise basic, unexplored question with rich physics. Recently, we have successfully characterized and described how the interaction between condensation/evaporation and capillary/osmotic phenomena dictate the equilibrium states of salt solutions confined in single nanopores. Now we are investigating larger scale phenomena in extended systems formed of many interacting pores (formation of arrays of microdroplets, stochastic nucleation patterns) and are trying to understand how they emerge from the behavior in single nanopores.
Contact
Olivier Vincent
22/10/2024
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Thèse :
Rémunération :
16
Bubble fronts in tree-like structures
Domaines
Condensed matter
Statistical physics
Biophysics
Soft matter
Physics of liquids
Physics of living systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental et théorique Description
When plant tissues are subjected to dry conditions, bubbles can spontaneously form in the complex vascular network of trees (xylem) conducting water, resulting in the embolism of these tissues (Fig. a-b). With climate change, it is thought that such events will occur more frequently and threaten the survival of forests and crops. However, the physics of the appearance, growth, and propagation of the bubbles in xylem (which combines microscale vessels, variations in wettability, and random, nanoscale membranes) is still poorly understood. With a combination of numerical simulations and experiments, we aim at establishing the general features of bubble propagation in xylem-like structures, and how the nonlinear coupling between several mechanisms (stochastic bubble nucleation, diffusion-limited growth, capillary breakthrough, poroelastic relaxations, osmotic phenomena, etc.) dictate the dynamics and patterns of gas invasion in disordered structures.
Contact
Olivier Vincent
22/10/2024
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Thèse :
Rémunération :
17
Quantum imaging using high harmonic states of light
Domaines
Quantum optics/Atomic physics/Laser
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 main objective of the internship will consist in using a pair of non-degenerated entangled photons at 2 harmonics from the high harmonic frequency comb to perform a quantum imaging experiment . We will study the possibility of transferring the sensing and resolution benefit from one spectral range to another one.
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. Ultimately, the candidate will investigate novel protocols to create high-resolution label-free images of complex structures (e.g. cells) embedded inside biological tissues.
Contact
Hamed Merdji
18/10/2024
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Thèse :
Rémunération :
18
Multipartite entanglement in semiconductor high harmonic generation
Domaines
Quantum optics/Atomic physics/Laser
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
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 the process of high harmonic generation in semiconductors 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 will verify genuine multipartite entanglement of the photons in the time/frequency domain. The approach will be further extended to verify multi-partite entanglement between even more optical modes.
Contact
Hamed Merdji
18/10/2024
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Thèse :
Rémunération :
19
Multipartite entanglement in semiconductor high harmonic generation
Domaines
Quantum optics/Atomic physics/Laser
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
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 the process of high harmonic generation in semiconductors 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 will verify genuine multipartite entanglement of the photons in the time/frequency domain. The approach will be further extended to verify multi-partite entanglement between even more optical modes.
Contact
Hamed Merdji
18/10/2024
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Thèse :
Rémunération :
20
Attosecond control of quantum states of light
Domaines
Quantum optics/Atomic physics/Laser
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
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 quantum states of light well before the decoherence of the system occurs. We recently reported the violation of the Cauchy-Schwarz inequalityas as a direct test of multipartite entanglement in the HHG process. The internship will consist in realizing a platform that will allow controlling the HHG quantum state on attosecond time scale, This opens the vision of quantum processing on unprecedented timescales, an evident perspective for future quantum optical computers. For M2 students: only candidates motivated to follow with a PhD in this topic will be considered. L3 and M1 students are welcome.
Contact
Hamed Merdji
18/10/2024
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Thèse :
Rémunération :
21
Light in Complex Media : from imaging to computing
Domaines
Quantum optics/Atomic physics/Laser
Quantum Machines
Quantum information theory and quantum technologies
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Expérimental et théorique Description
Scattering of light in heterogeneous media, for instance the skin or a glass of milk, is usually
considered an inevitable perturbation or even a nuisance. Through repeated scattering and
interferences, this phenomenon seemingly destroys both the spatial and the phase information
of any laser illumination.By « shaping » or « adapting » the incident light, it is in principle possible to control the propagation and overcome the scattering process. This concept has been exploited in the last decade to focus and image through and in complex media, and opens important prospects for imaging at depth in biological media.
In the group we are currently exploring two main topics, combining synergistically optical design and numerical studies for : (a) non-invasive coherent (SHG, Raman) and incoherent (multiphoton fluorescence) imaging, leveraging computational microscopyconcepts and (b) exploiting random mixing induced by the propagation of light through a complex medium for various computational tasks, allowing the intriguing concept of computing with disorder.
We have multiple funded ongoing projects along these two directions and welcome motivated
applicants for internship, with a solid background in physics, and an interest in machine learning, optics, imaging and computing.
Contact
Sylvain Gigan
16/10/2024
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Thèse :
Rémunération :
22
Fabrication and characterization of gradient soft solids
Domaines
Soft matter
Type de stage
Expérimental et théorique Description
The aim of this project is to establish the link between fabrication protocols and mechanical gradients, in model soft solids. The fabrication method will rely on layering, a technique at the basis of 3D printing, and the characterization on micromechanics experiments, which allow for the visualization of materials displacements in the three spatial directions. Beyond opening new ways to design and control soft solids, this project will have far-reaching fundamental implications in the fields of multiphasic materials, 3D printing, and polymer physics.
Contact
Nicolas Bain
15/10/2024
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Thèse :
Rémunération :
23
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
15/10/2024
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Thèse :
Rémunération :
24
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
15/10/2024
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Thèse :
Rémunération :
25
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
15/10/2024
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Thèse :
Rémunération :
26
Locomotion in granular media
Domaines
Soft matter
Physics of liquids
Physics of living systems
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental Description
Many living species thrive in granular environments, such as sand. Navigating through these granular terrains poses significant challenges, as these materials are heterogeneous, highly dissipative, and exhibit complex mechanical responses. As a result, animals serve as a remarkable source of bioinspiration for developing efficient strategies to move in such environments. At the FAST laboratory, we experimentally investigate the various strategies employed by animals to traverse sandy substrates, assessing their effectiveness and robustness. To this end, we develop bio-inspired robots and active systems, studying their behavior within a model granular environment. The goal of these experiments is to understand the underlying physics governing the interactions between moving objects and granular materials. If you are interested in animal locomotion, the mechanics of granular materials, or robot design and control, please contact us.
Contact
Baptiste Darbois Texier
14/10/2024
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Thèse :
Rémunération :
27
Friction and elasticity of folded polymer films
Domaines
Soft matter
Type de stage
Expérimental et théorique Description
Thin elastic sheets or wires easily fold when deposited on substrates. The relaxation of these folds or wrinkles depend on the ability of the sheet to slide on the substrate, while the elastic energy stored in the folds or wrinkles promotes the relaxation of the shape. Hence, such problems interestingly couple elasticity to frictional and sliding behaviors in thin elastic sheets.
The internship aims at exploring several aspects : How does the interplay between film deformation and friction affect the development of buckling instabilities and fold trapping? What is the contribution of film roughness and polymer viscoelasticity? To answer to these questions, we will carry out experiments in which a viscoelastic polymer strip is laid at imposed vertical velocity on a glass plate while the development of buckling instabilities and friction at the rough contact area at the glass/strip interface are continuously monitored. Based on these observations, we will seek to develop a physical description of the role of friction in the formation and trapping of wrinkles in relation to the mechanical and roughness properties of the polymer film.
Contact
Emilie VERNEUIL
Laboratoire : SIMM - ESPCI - UMR7615
Equipe : Sciences et Ingénierie de la Matière Molle
Site Web de l'équipe
Equipe : Sciences et Ingénierie de la Matière Molle
Site Web de l'équipe
10/10/2024
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Thèse :
Rémunération :
28
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
07/10/2024
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Rémunération :
29
Gravitational collapse of a granular column reinforced with fibres
Domaines
Soft matter
Hydrodynamics/Turbulence/Fluid mechanics
Type de stage
Expérimental Description
Introducing a small amount of flexible fibres into a granular medium is known to significantly increase the mechanical strength of the material. However, little is known about the flowing behaviour of grain/fibre mixtures. The aim of this internship is to study the effect of the addition of fibres on the flow behaviour of a granular column collapsing under the effect of gravity. We will quantify the collapse dynamics of the column and the final shape of the deposit as a function of the volume fraction of the fibres, their aspect ratio and their flexibility
Contact
Baptiste Darbois Texier
04/10/2024
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Thèse :
Rémunération :
30
Crystallization of nanomaterials: theory and simulation
Domaines
Condensed matter
Statistical physics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Théorique, numérique Description
Research overview
The formation of a crystal is triggered by the emergence of a nucleation core. Classical nucleation theory (CNT) is widely employed to discuss its nature and its origin. In CNT, the thermodynamically stable phase is always the one that grows first and its size is then driven by the free energy competition between how much it costs to build a liquid-crystal interface and the gain from growing the crystal. Yet, following Ostwald’s rule, another structure may emerge beforehand if it is closer in free energy to the mother phase. Then, structural and also chemical reorganizations happen during the growth. This multi-stage nucleation mechanism already appears in bulk systems but can be amplified in nanocrystal nucleation where surface effects and chemical reactivity are enhanced. For nanoscience to be inspired by the practical applications instead of still being driven by the synthesis possibilities, it is crucial to reach a better understanding of the unique crystallization mechanisms leading to nanocrystals.
Simulation project
Atomistic simulations will be performed to study crystallization of binary particles. Examples will be taken from well-studied materials including CuZr, NiAl, NaCl, Water... We will investigate the correlation between the thermodynamic conditions and the final nanoparticles. The goal is to ultimately better understand how nucleation theory is affected by downsizing to the nanometric scale.
Contact
Julien LAM
01/10/2024
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Rémunération :
31
Machine-learning approaches to model interatomic interactions
Domaines
Condensed matter
Statistical physics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type de stage
Théorique, numérique Description
Research overview
Materials can be studied using computer simulation which enables one to probe the motion of each constituent atoms and to build correlations between the macroscopic properties and the microscopic behaviors. On the one hand, traditional quantum mechanics methods provides particularly accurate results up to the electronic structure of the material. Yet, the drawback of this method concerns its computational cost which prevents from studying large system sizes and long time scales. On the other hand, effective potentials have been developed to mimic atomic interactions thereby reducing those issues. However, these potentials are often built to reproduce bulk properties of the materials and can hardly be employed to study some specific systems including interfaces and nanomaterials. In this context, a new class of interatomic potentials based on machine-learning algorithms is being developed to retain the accuracy of traditional quantum mechanics methods while being able to run simulations with larger system sizes and longer time scales.
Simulation project
Using computer simulations, the student will construct a database that should be representative of the different interactions occurring in a specific material. Machine-learning potentials based on the least-angle regression algorithm as well as neural network potentials will be trained and their accuracy will be studied as a function of the size and the complexity of the database.
Contact
Julien LAM
01/10/2024
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Thèse :
Rémunération :