Probing quantum coherence in artificial atoms with relativistic electrons
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Quantum information theory and quantum technologies
Quantum optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
Can a fast electron probe the quantum coherence of an artificial atom? Quantum coherence is central to quantum physics and underpins quantum information processing. Measuring it in individual systems such as quantum dots with nanometer spatial resolution would open new possibilities for exploring light–matter interactions and developing approaches to quantum-state readout.
We now seek to cross a new frontier in quantum science and technology: accessing the quantum coherence of an individual artificial atom with a relativistic electron. The central question is whether, and how, this coherence can be encoded in the electron’s state and experimentally read out.
This M2 internship, with the prospect of continuing into a PhD, will contribute to this effort within the ERC Advanced Grant FreeQCC. The project combines a state-of-the-art monochromated transmission electron microscope, a laser system, and engineered samples designed to enhance electron–light–matter interactions. During the internship, the student will help develop the optical setup, participate in experiments, and analyze the resulting data.
We seek a curious and motivated student interested in quantum physics, nano-optics, and experimental research. The project offers the opportunity to explore an emerging research frontier with implications for both fundamental physics and future quantum technologies, through a combination of advanced instrumentation, experiments, and theory.
This theoretical physics internship will explore new variational phase-space methods for understanding quantum and complex dynamics beyond the reach of exact numerical simulations.
The starting point is our recent work published in Physical Review X (2026), which combines multi-Gaussian representations of the Wigner distribution, variational principles and automatic differentiation. The Wigner distribution represents quantum states in phase space, capturing correlations and quantum interference. Our approach turns their dynamics into the evolution of a compact set of parameters, opening new possibilities for studying large interacting systems.
The project will investigate how these ideas can be extended and applied across a broad range of problems: open and driven quantum systems, quantum many-body dynamics, nonlinear light-matter interactions, and potentially nonlinear, stochastic and classical complex systems.
The research direction will be adapted to the student's interests, combining analytical developments with numerical simulations.
Supervisor: Prof. Cristiano Ciuti, MPQ, Université Paris Cité / CNRS.
Contact: cristiano.ciuti@u-pariscite.fr
Magneto-Ionic Nanodevices for Neuromorphic Computing
Domaines
Condensed matter
Low dimension physics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
Scientific project: Controlling magnetic properties through voltage-driven ionic motion opens exciting opportunities for next-generation spintronic technologies, including reconfigurable multistate memories and neuromorphic hardware. By combining ionic and magnetic degrees of freedom, magneto-ionic nanodevices offer new ways to emulate the adaptive behavior of biological synapses. Our group at C2N has demonstrated large, reversible, and non-volatile voltage-induced changes in the magnetic properties of spintronic nanodevices, as well as their potential to realize bioinspired synaptic functionalities.
We are seeking a highly motivated master’s student to join our team for an experimental research project at the interface of magnetism, ionics, and neuromorphic computing. The project will investigate how magneto-ionic gating can control the dynamics of magnetic domain walls driven by current pulses in nanodevices. By exploring the interplay between ionics and spintronics, the student will develop and characterize new device functionalities for artificial synapses. The ultimate ambition is to combine an ensemble of devices to evaluate its performance for given learning tasks.
The student will benefit from our team’s complementary expertise in magneto-ionics, neuromorphic computing architectures, and nanofabrication, while gaining hands-on experience in state of the art experimental research.
The constant pace of discoveries of new radio sources in the Universe calls for new receivers
which would be faster, more sensitive and less subject to parasitic signals. An outstanding
problem which could benefit from new detection schemes is, for example, the accurate measurement of the 21-cm, strongly red-shifted, cosmological signal, in the low 100 MHz range. Many pioneering experiments have been carried out, such as EDGES, REACH, NENUFAR or SARAS, but the cosmological signal has been elusive so far.
The main idea to be developed in this project is to use quantum technologies, and in particular multicavity setups with granular aluminum Josephson circuits in order to develop a quantum correlator which could unlock very feeble cosmological signals connected to deep questions about the early universe or fast bursts entailing ununderstood astrophysical processes. We have recently shown that we could have a clear advantage of a cavity quantum electrodynamics setup over a classical receiver chain for the very low redshifted 21-cm signal from benchmark constellations such as the Cygnus or Cassiopea. We would like to test the same ideas on a quantum correlator first on pulsars or galactic masers as a benchmark before going to the very high redshifted signals.
Quantum simulation with a hybrid Rydberg atom platform
Domaines
Quantum optics/Atomic physics/Laser
Quantum information theory and quantum technologies
Type of internship
Expérimental
Description
The long lifetimes and strong dipole-dipole interactions of circular Rydberg atoms make them particularly appealing for the realization of quantum simulations. A recently-developed hybrid platform, that combines them with ancillary atoms excited to standard Rydberg levels, has enabled their local non-destructive measurement and manipulation, and the simulation of spin-exchange interactions over unprecedented timescales. The intern will participate in the development of a novel cryogenic version of the platform, where we will fully benefit from the long lifetimes of circular states. We will use the new setup to demonstrate quantum simulations in a subsequent doctoral work.
This activities of the group focus on the study of strongly correlated fermions in low-dimension. We explore how the interplay between strong confinement and strong interactions allowed by Feshbach resonances gives rise to Effective field theories generalized known paradigms in low dimension.
Probing the Fermi surface in a lattice with metastable helium atoms
Domaines
Quantum optics/Atomic physics/Laser
Quantum gases
Type of internship
Expérimental
Description
The helium lattice team exploits the properties of helium species to probe lattice gases atom-by-atom [1]. The apparatus, initially operated with the bosonic species helium-4 [2], led to study the Bogoliubov pairing through atom correlations [3,4], and to probe the superfluid-Mott transition through full counting statistics [5,6]. The detection method also applies to the fermionic species helium-3. Therefore, we have recently upgraded the apparatus to add helium-3 and produce a degenerate Fermi gas. In a near future, we will load the fermionic gas into lattices to perform studies of lattice fermions.
The Master 2 internship will aim at characterizing the Fermi surface of non-interacting lattice fermions, leading to a PhD thesis centered on interacting lattice fermions (e.g. Fermi-Hubbard physics) and momentum correlations. The intern will join on-going efforts of the experimental team to achieve (i) loading helium-3 gas into the optical lattices, (ii) acquiring the experimental data, varying experimental parameters such as temperature or lattice filling, and (iii) analyzing the single-atom-resolved distributions to characterize the Fermi surface.
[1] Phys. Rev. A 97, 061609 (2018); Phys. Rev. X Quantum 5, 040324 (2024).
[2] Phys. Rev. Lett. 126, 045301 (2021).
[3] Nature Physics 17, 1364 (2021).
[4] Nature Physics 21, 57-62 (2025).
[5] Nature 655, 1148 (2026).
[6] arXiv:2609.03433 (2026).
Quantum information theory and quantum technologies
Type of internship
Expérimental et théorique
Description
The internship project takes place at the ENS Lyon Physics Laboratory. It offers the chance to build a random-access quantum memory, a device that stores several quantum states and releases any one of them on demand, a key ingredient for parallel quantum processing. Electron spin ensembles store microwave states about 100 times longer than superconducting qubits but are limited to below 10% efficiency, a challenge the project tackles using ytterbium ions in CaWO₄, which keep state-of-the-art coherence at high concentration and operate at zero magnetic field. The milestones are to test a new deposition technique that boosts spin–resonator coupling, then demonstrate storage of classical and quantum microwave fields at an efficiency close to 100%.
Narrative epidemics: How ideas spread, compete, and fade
Domaines
Statistical physics
Physics of living systems
Type of internship
Théorique, numérique
Description
Why do some narratives suddenly invade public attention, persist for weeks or years, and then disappear, while most never take off? This project will develop a quantitative theory of narrative dynamics inspired by epidemiology and statistical physics. Narratives will be treated as competing contagions spreading through a population with finite attention, so that the success of one narrative necessarily limits the space available to others. Large textual datasets will be used to reconstruct empirical narrative trajectories and calibrate a
low-dimensional macroscopic model. A further theoretical objective will be to investigate whether this effective dynamics can be derived from a microscopic interacting-agent model, for instance a Random Field Ising Model (RFIM)-type description combining heterogeneous individual preferences and social imitation.
Small-scale chaos and the Vlasov limit of N-body dynamics
Domaines
Statistical physics
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Kinetic theory ; Diffusion ; Long-range interacting systems
Type of internship
Théorique, numérique
Description
This internship focuses on the role of small-scale chaos in the convergence of the Klimontovich
equation towards the Vlasov one. See attached PDF for the full proposal.
Hybrid and non-Gaussian optical quantum state engineering
Domaines
Quantum optics/Atomic physics/Laser
Quantum information theory and quantum technologies
Quantum optics
Non-linear optics
Type of internship
Expérimental et théorique
Description
The use of light in quantum information processing and networks has historically been split between two communities. On one side is the continuous-variable (CV) approach, which treats optical fields as waves. On the other side is the discrete-variable (DV) approach, harnessing the properties of individual photons. By considering a hybrid approach bridging the two, one could envision quantum architectures where the two encodings can be for instance interchanged fittingly to the task at hand.
In this hybrid quantum optics context, the LKB team demonstrated the first engineering of hybrid entanglement of light, i.e. entanglement between particle- and wave-like optical qubits. This novel resource enabled then to demonstrate the remote state preparation of cat-state qubits and recently the teleportation between different encodings, realizing thereby a first quantum-bit encoding converter.
The research of the group is now focusing into two directions. The first one aims at harnessing further the unique benefits of the hybrid optical approach for quantum connections, to develop optical quantum connections versatile enough to connect different physical quantum platforms and faithfully carry a broad range of quantum states. The second direction builds on the high-fidelity non-gaussian resources available on the experimental setup and aims at the realization of complex optical non-gaussian states that can find applications in bosonic error correcting codes.
Waveguide-QED - combining cold atoms and nanophotonics (2 internships)
Domaines
Quantum optics/Atomic physics/Laser
Quantum information theory and quantum technologies
Quantum optics
Type of internship
Expérimental et théorique
Description
Controlling light-matter interaction at the single-quantum level is a long-standing goal in optical physics, with applications to quantum optics and quantum information science. However, single photons usually do not interact with each other and the interaction needs to be mediated by an atomic system. Enhancing this coupling has been the driving force for a large community over the past two decades.
In contrast to the cavity-QED approach where the interaction is enhanced by a cavity around the atoms, strong transverse confinement in single-pass nanoscale waveguides recently triggered various investigations for coupling guided light and cold atoms. Specifically, a subwavelength waveguide can provide a large evanescent field that can interact with atoms trapped in the vicinity. An atom close to the surface can absorb a fraction of the guided light as the effective mode area is comparable with the atom cross-section. This emerging field known as waveguide-QED promises unique applications to quantum networks, quantum non-linear optics and quantum simulation. Recently, the LKB team pushed the field for the first time into the quantum regime by creating an entangled state of an array of atoms coupled to such a waveguide. Two experiments are dedicated to this waveguide-QED effort and internships/PhD projects are proposed on both of them.
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Théorique, numérique
Description
In this internship, motivated by recent experiments on graphene and TMD multilayers, we will theoretically investigate 2D multilayers that could host chiral Majorana modes. We will also study the creation of Majorana wave packets and their time-dependent propagation and manipulation.
The objective of this research project is to investigate the interplay between partial postselection and conditional feedback in monitored many-body quantum systems. To explore these effects, we will consider a many-body system of non-interacting electrons undergoing entangling unitary evolution interrupted by disentangling quantum measurements. We will study how the resulting dynamics are modified by local particle injection and depletion, as well as by local and non-local feedback protocols and adaptive partial postselection.
Nouveaux états électroniques de la matière corrélée
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
Quantum matter, such as high temperature superconductivity, is generally emergent, meaning that the physics cannot be understood by the sum of the individual components. The crucial additional ingredient is the interactions between the atoms (or lattice), electrons and spins. To directly study these interactions, we are currently developing a time-resolved scanning tunnelling microscope. This instrument will provide direct access to the surface atoms and the local electronic structure, while at the same time enabling read-out and/or excitation at GHz frequencies (i.e. nanosecond timescales).
During this internship, you will be the first to test and use this new instrument. Initially, measurements will be performed at room temperature to make sure that the microscope works correctly. Then, exploration at low temperature and high frequency will follow, with the aim of uncovering previously inaccessible information about the workings of quantum matter.
Optical photons are excellent carriers of quantum information, but their lack of mutual interactions is a major roadblock for quantum technologies. Our setup enables such interactions by transiently injecting the photons into an intra-cavity cold atomic gas and converting them into strongly interacting Rydberg polaritons. The Rydberg-blockaded cloud then acts as an effective two-level superatom with an enhanced coupling to light. We can coherently manipulate its state, efficiently detect it, and observe state-dependent pi phase flips on the light reflected from the cavity as required for many quantum engineering tasks. We obtained the first fully deterministically-generated free-propagating states of light with negative Wigner functions. We also developed a deep theoretical understanding of the rich physics and the abilities of the superatoms, validated by experimental results.
This platform opens many perspectives for developing deterministic multi-photon gates, performing quantum measurements impossible with current techniques, generating non-classical free-propagating resource states, and studying strongly correlated quantum fluids of light.
Magnetic resonance of single biomolecules with quantum superconducting circuits
Domaines
Biophysics
Quantum Machines
Quantum information theory and quantum technologies
Quantum optics
Type of internship
Expérimental
Description
Superconducting qubits, developed for quantum computing, can also serve as sensitive detectors for probing the magnetic properties of individual molecules. The Quantronics group has demonstrated the detection of individual electron spins in crystals by counting the microwave photons they emit with a transmon qubit [1], as well as the coherent control of neighbouring nuclear spins [2]. This internship will contribute to our ongoing work on molecular spins in frozen solution, with the aim of performing magnetic resonance spectroscopy on individual spin-labelled biomolecules.
Electron spin resonance (ESR) provides information about the local electronic and magnetic environment of molecules. In structural biology, interactions between spin labels can also be used to measure distances within proteins. Conventional experiments average over many molecules, obscuring their individual properties and limiting spectroscopic resolution. Measuring molecules individually could overcome this ensemble broadening and reveal local environments and spin couplings that are otherwise unresolved, opening access to more detailed structural information.
A new source at 578 nm for clock interrogation and shelving of Yb atoms
Domaines
Quantum optics/Atomic physics/Laser
Quantum optics
Non-linear optics
Quantum gases
Metrology
Type of internship
Expérimental
Description
The internship will take place in the ytterbium lattice clocks team at LTE, Observatoire de Paris. Two topics are proposed in parallel: the design and the construction of a 578 nm source based on non-linear optics, and the demonstration of an atomic drain technique aiming at shelving atoms in metastable states so as to decouple the dynamics of a magneto-optical trap from the capture in a deep optical lattice.
Bio-inspired superconducting sensors for sub-THz technologies
Domaines
Condensed matter
Physics of living systems
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 of internship
Expérimental et théorique
Description
The overall objective is to develop an ultrasensitive, on-chip sub-THz spectrometer that mimics the cochlea’s remarkable ability to decompose complex audio signals. This will be achieved by combining graded metamaterial designs with the nonlinear dynamics of superconductors.
The internship will consist in setting up a 100GHz measurement apparatus and simulating, then fabricating a first prototype to verify the properties of the rainbow trapping in the linear case.
Do not hesitate to contact us, if you are interested !
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental et théorique
Description
The goal of this project is to build a quantum spectrometer in the meV range that opens the road for the study of quantum coherences in low dimensional systems. It lies at the frontier between microwave and optics will enrich two fields of research and give access to mesoscopic phenomena such as magnonic excitations.
Feel free to contact me if you are interested!
Can biodiversity be seen from space? Multiscale complexity in remote-sensing images to predict ecosystem trends.
Domaines
Statistical physics
Biophysics
Physics of living systems
Type of internship
Théorique, numérique
Description
A biodiverse landscape may not simply be greener or more heterogeneous. It may possess a distinctive organisation across scales: habitat mosaics, edges, corridors, characteristic patch sizes, lacunarity and long-range correlations. Aerial and satellite images preserve much of this geometry, yet standard ecological products often compress it into pixel classes or a few averages. The challenge is to determine whether multiscale observables carry robust ecological information and, as a possible extension, whether they reveal spatial reorganisation before visible degradation.
{Mapping atmospheric convection from paragliding trajectories
Domaines
Statistical physics
Physics of living systems
Hydrodynamics/Turbulence/Fluid mechanics
Type of internship
Théorique, numérique
Description
Can thousands of recreational flights become an observatory of atmospheric convection? This internship will use large-scale paragliding trajectories to investigate the structure and dynamics of thermal updrafts. Combining atmospheric physics, trajectory analysis and statistical inference, we will explore what nearby pilots can reveal collectively about an invisible, evolving flow, while accounting for the selective way they explore it.
2D materials architectures for advanced tuning of thermal properties
Domaines
Condensed matter
Low dimension physics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
The internship explores heat and charge transport in nanostructured graphene to improve thermoelectric conversion and explore thermal rectification. Using geometrically modified graphene with periodic nano-holes or nanocostriction, it aims to control phonon and electron mean free paths, enabling asymmetric heat conduction and enhanced Seebeck effect. The student will fabricate devices (graphene transfer, e-beam lithography, etching), measure electrical and thermal properties (Seebeck coefficient, electrical and thermal conductivity, rectification), and analyze results through finite element simulations. The project offers practical training in 2D materials and advances understanding of geometry-driven thermal and thermoelectric control.
Molecular membrane fabrication for quantum technologies
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Low dimension physics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
The central objective of this internship is to establish a reproducible route for fabricating europium
molecular membranes and, crucially, to determine whether their exceptional optical properties are
preserved after exfoliation and transfer. The student will optimize the mechanical exfoliation
conditions to increase the yield of thin, large-area flakes; develop deterministic dry-transfer protocols
onto photonic substrates such as SiC, SiO2/Si and glass; characterize membrane thickness,
morphology and crystalline quality using optical interference microscopy, atomic force microscopy
and Raman spectroscopy; and investigate their luminescence and optical homogeneous linewidths at
cryogenic temperatures using spectral hole burning. Comparison with bulk crystals will allow the
influence of exfoliation, reduced thickness and substrate coupling on the optical coherence of the
molecular material to be established.
Single-Photon Detection and Correlation Measurements in Ultracold Atoms
Domaines
Quantum optics/Atomic physics/Laser
Quantum information theory and quantum technologies
Quantum optics
Quantum gases
Type of internship
Expérimental
Description
The Exotic Quantum Matter (EQM) Group is looking for a highly motivated Master 2 student to characterize a single-photon detection system that will subsequently be integrated into the experimental platform. The EQM group operates a quantum simulator based on ultracold potassium atoms to study strongly interacting quantum matter and light–matter interactions.
The EQM team has already demonstrated strong photon–photon interactions through classical measurements of optical intensity and phase. The next step is to investigate these interactions at the level of individual photons, where quantum correlations become directly accessible.
The internship will establish a two-channel single-photon detection system based on two single-photon avalanche diodes (SPADs) and a high-resolution photon arrival-time tagger. The system will be used to measure the second-order photon correlation function g²(τ).
Quantum information theory and quantum technologies
Metrology
Type of internship
Expérimental
Description
Le stage proposé consistera à participer au premier essai aéroporté d'un gravimètre quantique de seconde génération, plus compacts, plus précis et permettant non seulement de mesurer l’amplitude du champ de gravité, mais également d’en déterminer l’orientation . Dans un premier temps, le stagiaire mettra en place une procédure de calibration des capteurs auxiliaires nécessaires au fonctionnement du gravimètre. Dans un deuxième temps, il participera à une campagne de mesures en vol aux îles Féroé. Enfin, il contribuera au traitement et à l’analyse des données acquises pendant les vols. Ce stage permettra au stagiaire d’acquérir des compétences à l’interface de plusieurs domaines : physique quantique, métrologie de haute précision, instrumentation et traitement de données. Le stage pourra se poursuivre par une thèse portant sur la suite du développement de ce gravimètre quantique, avec pour objectif la réalisation de mesures vectorielles du champ de gravité.
Métrologie quantique avec des atomes de Rydberg dans des pinces optiques
Domaines
Quantum optics/Atomic physics/Laser
Quantum information theory and quantum technologies
Metrology
Type of internship
Expérimental
Description
Ce stage s'inscrit dans un projet visant à explorer une nouvelle génération de capteurs de champs électromagnétiques avec des atomes froids de Rydberg. L'idée est de combiner la grande sensibilité des atomes de Rydberg au très bon degré de contrôle et de cohérence qu'il est possible d'atteindre avec des atomes froids contrôlés dans des pinces optiques. Cela ouvre la voie à de nouvelles applications dans des domaines variés comme : l’imagerie THz, la détection électromagnétique, la calibration des déplacements lumineux dans les horloges atomiques et des expériences de métrologie quantique où l'intrication entre atomes est mise à profit pour améliorer la sensibilité des mesures.
Notre dispositif expérimental a permis la démonstration de méthodes innovantes pour la mesure d’un champ micro-onde avec des atomes froids de Rydberg [Phys. Rev. Applied 22, 044039 ; arXiv:2608.07260]. L'objectif de ce stage est d’explorer de nouvelles techniques de mesure des champs électromagnétiques avec des atomes froids de Rydberg dans des pinces optiques.
Intégré au sein de l'unité DPHY/SLM de l'ONERA, qui est un acteur mondialement reconnu des capteurs à base d'atomes froids, vous serez également amené(e) à interagir avec le département électromagnétisme et radar de l'ONERA ainsi qu'avec nos partenaires académiques et industriels
Looking for potential variations of the proton-to-electron mass ratio and other tests of fundamental physics via precision measurements with molecules
Domaines
Quantum optics/Atomic physics/Laser
Metrology
Type of internship
Expérimental
Description
This internship will focus on measuring mid-infrared molecular transitions of methanol (CH3OH), ammonia (NH3), and other molecules known for their enhanced sensitivity to changes in µ. The work will involve achieving subDoppler spectroscopic resolution to reach target laboratory frequency accuracies of ~100 Hz needed for comparisons with astronomical observations. This activity is part of the ANR Ultiµos project, a collaborative effort which seeks to refine current constraints on the possible variation of µ which involves leading research institutions, including Laboratoire Kastler Brossel (LKB, L. Hilico) and MONARIS (C. Janssen) at Sorbonne Université. The three partners of the Ultiµos consortium will collaborate to conduct measurements in different spectral windows, to identify transitions as targets for future Earth/space comparison campaigns, which could further tighten constraints on
variations of µ. Other collaborators, such as Vrije Universiteit Amsterdam and Onsala Space Observatory, will provide theoretical and observational/astronomical support to complement the experimental efforts.
High-Sensitivity Microwave Spectroscopy for Precision Measurements and Tests of Fundamental Physics
Domaines
Quantum optics/Atomic physics/Laser
Metrology
Type of internship
Expérimental
Description
The master student will join the effort at LPL to develop a new-generation compact and versatile microwave (MW) spectrometer operating over the 2–20 GHz range. This instrument is conceived both as a high-sensitivity detector of internal quantum states in polyatomic molecules and as a precision tool for molecular frequency metrology. The spectrometer will enable cross-checks between MW rotational frequencies and mid-infrared (MIR) rovibrational data planned to be measured at the 100 Hz level in the frame of the ANR Ultiµos project. These comparisons are directly motivated by the search for potential variations of the proton-to-electron mass ratio µ, a fundamental constant whose stability can be tested by confronting laboratory data with MW astronomical spectra of molecules such as methanol and ammonia. These species possess transitions with strong sensitivity coefficients to µ, making them powerful probes of possible temporal or spatial variations of fundamental constants. In Ultiµos, spectroscopy with ultrastable MIR quantum cascade lasers provide ultra-precise MIR frequencies with relative uncertainties of 10 ¹². By using combination–difference schemes, these MIR data yield effective MW intervals that can be directly confronted with our SI-traceable MW measurements. Such dual determinations, based on entirely different experimental chains and affected by distinct systematic effects, are ideal for robust cross-validation of frequency values and uncertainty budgets.
Exploring non-Abelian geometric phases with mobile spins
Domaines
Condensed matter
Quantum information theory and quantum technologies
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
This project aims to perform direct measurements of non-Abelian geometric phases experienced by individual spins moving in materials with strong spin-orbit interaction. We will develop an experiment where single holes are displaced along closed loops inside 2D arrays of quantum dots in germanium at zero magnetic field. By studying the evolution of their spin states depending on the trajectory followed, we will evidence the non-Abelian geometric phases, study their properties and investigate their potential for quantum information processing.
Toward 2D electron gases with strong spin-orbit coupling in crystalline metal- semiconductor heterostructures
Domaines
Condensed matter
Type of internship
Expérimental
Description
The aim of this intership project and the following PhD thesis is to develop a strategy to preserve the strong Rashba effect in 2D heavy metallic layers on semiconducting surfaces and make use of these systems for spintronic applications. We will grow a dielectric capping material on the desired heavy metal in ultra-high vacuum environement, study the band structure of the heterostructures by ARPES and perform charge-spin conversion measurements by magneto-transport techniques.
The statistical physics of visual preference: What makes an image appealing?
Domaines
Statistical physics
Physics of living systems
Type of internship
Théorique, numérique
Description
Why do some images feel visually compelling while others appear dull, chaotic or artificial? This internship will investigate whether aesthetic preference can be related to measurable statistical properties of images. Building on our previous work on structural complexity, multiscale relevance, and quantitative color harmony, we will combine large human-preference datasets with interpretable descriptors of image organisation to identify which visual structures are consistently associated with appeal.
Cooperation in hybrid human-AI populations: Can artificial agents reshape collective behaviour?
Domaines
Statistical physics
Physics of living systems
Non-equilibrium Statistical Physics
Type of internship
Théorique, numérique
Description
As artificial agents become participants in social and economic interactions, even a small fraction of them may alter collective behaviour. This internship will investigate how cooperation emerges in populations containing both humans and artificial agents. Using empirical data from social-dilemma experiments together with simple statistical-physics and evolutionary-game models, we will ask when artificial agents stabilise cooperation, when they disrupt it, and which mechanisms control the transition between these regimes.
We propose an internship to implement quantum simulation scenarios with ultra-cold dipolar excitons, confined in nanoscopic electrostatic lattices. This semiconductor platform has shown a high level of performance. It relies on electron-hole pairs that are optically injected in a double quantum well, where gate electrodes imprint electrostatic lattices confining excitons. Here, a route is introduced to realize anyonic excitations in the lattice. Anyons are strikingly marked by a fractional quantum statistics. They are theoretically accessible to dynamically varying lattices of dipolar excitons. following so-called Floquet engineering.
Quantum information theory and quantum technologies
Type of internship
Expérimental et théorique
Description
Cat qubits protect quantum information in hardware. Two coherent states of a microwave resonator are held in place by a dissipation that removes photons only in pairs, which suppresses bit flips exponentially with the cat size. This dissipation is usually activated by a microwave pump, which also turns on parasitic terms. We instead bias a Josephson junction with a dc voltage, so that Cooper pairs tunnel at a frequency selecting the useful process while every unwanted term averages to zero. We have just demonstrated this mechanism in Lyon with Alice & Bob. The internship consists in measuring the next circuit and turning this dissipation into a qubit, first a two-component cat imaged by Wigner tomography, then a four-component cat calling for a high-impedance memory.
A superconducting qubit with built-in protection against errors
Domaines
Condensed matter
Quantum Machines
Quantum information theory and quantum technologies
Type of internship
Expérimental et théorique
Description
Quantum processors correct their errors in software, at a cost of roughly a thousand physical qubits per useful logical one. A protected qubit works differently. Its two logical states are placed so far apart in phase space that no local noise can connect them. Errors are suppressed by the geometry of the circuit rather than corrected after the fact. We identified a new circuit that should solve the current roadblocks of previous attempts at making such a device. During the internship, you will measure and characterize the first version of that circuit.
Moreover, we recently experimentally demonstrated that it is possible to remove any charge offset drift in superconducting circuits, which would greatly improve the coherence time of our qubit. You will also contribute to the development of a new fabrication recipe that stabilizes the charge offset deterministically.
Probing Short-Time Brownian Motion in 3D with Optical Traps
Domaines
Condensed matter
Statistical physics
Soft matter
Physics of liquids
Nonequilibrium statistical physics
Non-equilibrium Statistical Physics
Hydrodynamics/Turbulence/Fluid mechanics
Type of internship
Expérimental
Description
Push our optical trap toward a full 3D view of Brownian motion. Having proven we can track x(t) and y(t) under white light, cross-calibrated with our ultra-fast photodiode x(t) channel, join us to add a fast y(t) channel and a brand-new z(t) axis, the first steps toward a PhD probing particles near walls.
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental et théorique
Description
In reduced dimensionality, particles coined “anyons” can evade the familiar division between fermions and bosons with a fractional exchange phase between 0 and pi, with applications to topological quantum computation. Early on, quasiparticles of the Fractional Quantum Hall regime were identified as anyon candidates, and their fractional statistics was experimentally established in a few pioneer experiments in the early 2020s. It has been suggested that their existence extends way beyond this restrictive framework, and that they emerge for instance in bidimensional ballistic electron systems with strong Coulomb interactions, resulting in electron charge and statistics fractionalization.
The goal of this internship is to follow this novel approach with quantum circuit tools, combining quantum point contacts, single electron physics at high charging energies and ballistic edge channels of the Integer quantum Hall regime. The student will learn a variety of techniques mastered in the team (ultrasensitive conductance and quantum shot noise measurements, quantum thermal transport, electron interferometry), in order to reveal the anyonic nature of the system’s excitations, and characterize their quantum coherence.
Infrared electroluminescence from colloidal quantum dots
Domaines
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
Colloidal Quantum Dots (CQDs) are size-tunable semiconductors. They received the Nobel Prize in 2023 after being integrated into displays thanks to their spectrally narrow luminescence. While visible CQDs are now commercially available, their infrared counterparts have not yet released their full potential, whereas the short-wave infrared range lacks efficient non-coherent sources. The project aims to explore the design of light-emitting diodes operating in the 1 to 5 µm range. The infrared light-emitting layer is sandwiched between charge injection layers that selectively inject electrons and holes. In the visible range, the quantum efficiency can be as high as 20%, but it quickly drops as longer wavelengths are targeted (1% at 1.3 µm and 0.1% at 2 µm) due to the lengthening of the radiative lifetime and inefficient shielding, which makes non-radiative processes dominant. Thus, new concepts need to be introduced to circumvent this drop in efficiency. The project will explore new concepts related to charge injection based on energy transfer and cascade effects as strategies to generate electrical gain. A second aspect of the project will relate to the design and fabrication of photonic structures to achieve better light outcoupling.
Imaging carrier transport in cross-sectional III-nitride LEDs
Domaines
Quantum optics/Atomic physics/Laser
Condensed matter
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental et théorique
Description
Light Emitting Diodes (LEDs) made of nitride materials are universally used for energy-efficient lighting. However, such LEDs suffer from drastic drops in efficiency at high current densities and high emission wavelengths (green to red), whose causes are still debated due to their complexity. Understanding them requires to access carrier behavior inside the active region of the LED itself, taking into account microscopic structuration and heterogeneities. Most approaches in the literature focus on spatially averaged measurements, missing out the core of the problem.
This project proposes to develop a novel approach to directly image carrier behavior (injection, recombination et escape) in the active region of an in operando LED. The aim is to perform a pump-probe electrical and optical excitation on a cleaved device observed in cross-section in a low energy electron microscope. This approach includes several challenging steps, among them the cleavage of an operating device for an observation in cross-section and the development of a mixed electrical and optical excitation of the LED under the microscope. Numerical modelling will be developed to support experimental findings.
Acousto-optic interaction for non-linear integrated mid-infrared photonics
Domaines
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
The goal of this internship is to develop and characterize nonlinear acousto-optic devices operating in the mid-infrared (wavelength of 3-8µm), leveraging broadband transparency and piezoelectricity of III-V semiconductor heterostructures. These devices will perform phase modulation, but also potentially on-chip optical routing, a pre-requisite for magnetic field-free optical isolation.
The internship will be mostly experimental, involving the use and development of two existing setups. The first one is a mid-IR integrated photonic bench allowing to characterize the operation of the devices (see above, right). The second one is a heterodyne interferometer, that allows to image the SAW-related vibration (amplitude and phase) of the sample surface to characterize the acoustic properties of the devices (see above, left).
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental et théorique
Description
Description
See pdf file for all the details
Extremely brief summary:
The goal of the internship is to develop and optimize mid-IR nonlinear mirrors, supported by recent results from the host team, that target comb operation of fiber lasers at lambda=3.5 and 4.6 um, and explore the mode locking regime. Our collaborators at CORIA/CNRS laboratory have developed these novel sources, and our SESAMs will enable their mode-locking operation
Ground-state cooling of multiple nanoparticles in optical levitation
Domaines
Quantum optics/Atomic physics/Laser
Nonequilibrium statistical physics
Quantum optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
Optical levitation is a subfield of optomechanics, in which a nanoparticle is trapped in a vacuum at the focal spot of a microscope objective. Because levitated systems outperform other mechanical resonators, they offer the tantalizing prospect of investigating quantum mechanics at the mesoscale. To display quantum properties, the nanoparticle must be cooled down close to its ground state, which is typically achieved through the monitoring of its displacements and a modulation of the laser’s intensity. Currently, the most exciting endeavor in the field lays in performing levitation with many-body systems. Many-body levitation would offer the opportunity to observe effects for the first time, like the mesoscopic entanglement of nanoparticles. Sadly, conventional cooling techniques, cannot be multiplexed and fail badly to cool several elements in parallel.
Throughout this internship, the candidate will experimentally implement a new cooling technique intended to achieve the first-ever cooling of a many-body system composed of multiple nanoparticles in levitation. Compared to former strategies, here, a spatial light modulator is used to spatially shape the wavefront of the laser beam. Such a modulation enables to exert simultaneously adapted optical forces on all the nanoparticles in order to reduce their individual vibrational motions, which ultimately leads to the cooling of the many-body system. A funding is available to continue this internship through a PhD.
Quantum informational resources in quantum optics and superselection rules: the role of detection.
Domaines
Quantum information theory and quantum technologies
Quantum optics
Metrology
Type of internship
Théorique, numérique
Description
Quantum information protocols are well defined mathematically, and there exist different benchmarks for establishing the necessary resources for potential quantum advantage, as for instance the discrete Wigner function negativies or "magic". At the same time, physical systems, and in particular, bosonic systems - as the quantum electromagnetic field - can be used to encode quantum information or, alternatively speaking, simulate quantum informational protocols. Nevertheless, for such systems, the "magical" resources enabling quantum advantage over classical simulations - i.e., enabling the efficient simulation of quantum protocols - are subjected to physical constraints, as symmetries and conservation laws. While abstract qubits have no particular symmetry, photons are bosons, symmetric identical particles.
During this internship, we will address the interplay between physical and informational resources to determine how detection may be seen as a non-classical resource in quantum optics based quantum information protocols. This will be done by constructing a original framework where the phase reference of quantum optical states is explicitly treated as a resource. In general, this resource is implicit and disregarded, obscuring the assessment of the resource tradeoff of bosonic quantum information protocols. We will analyze, in particular, the role of detection in BosonSampling protocols and in homodyne detection, that is usually considered as resourceless.
Ultra-fast mid-IR modulators for applications to frequency combs
Domaines
Condensed matter
Low dimension physics
Non-linear optics
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental et théorique
Description
See pdf file for all the details
Extreme brief summary:
The goal of the internship is to develop electrically reconfigurable meta-surfaces whose optical properties, in reflection/ absorption, can be addressed electrically on ultra-fast timescales. In particular, we target ultra-fast amplitude modulators for the mid-infrared spectral range.
These developments are crucial for applications such as laser phase stabilization, spectroscopy, frequency comb generation, mode-locking, optical communications.
Shaping the polarization of light for tip-enhanced photoluminescence
Domaines
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
The goal of the internship is to develop an optical spectroscopy technique that is spatially resolved at the nanoscale, which is known as tip-enhanced photoluminescence (TEPL). This technique employs a laser beam focused onto the apex of a plasmonic metal tip (gold or silver) within an atomic force microscope (AFM) or scanning tunneling microscope (STM). To maximize the field enhancement effect at the tip apex, the focused beam must be radially polarized. To achieve this specific polarization, the intern will use a liquid-crystal polarization converter. The intern will then couple this beam to the plasmonic tip of an AFM or STM microscope, contribute to developing the software interface for controlling the optical detectors, and conduct TEPL experiments on semiconductor nanomaterial samples.
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
Type of internship
Expérimental et théorique
Description
The objective of the internship and the thesis is to investigate the combined effect of nonlinearities and complex interferences in these optical graphs, particularly regarding the formation and dynamics of soliton states. In a second time, we will inject non-classical light (squeezed light or entangled photons) to test if entanglement is sensitive to chaos.
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
Photonic time crystals -optical systems that are strongly and periodically modulated in time- have recently emerged as a novel paradigm for controlling light–matter interactions through temporal modulation, analogous to how conventional spatial photonic crystals manipulate light through spatial structuring. Building on our recent demonstration of a photonic time crystal using a plasmonic metamaterial operating at Terahertz frequencies, this internship aims to lay the groundwork for realizing a quantum plasmonic metamaterial time crystal, that is a photonic time crystal that can operate in the few-photon regime. This will require developing a Terahertz spectroscopy setup with extended frequency coverage as well as the design and characterization of advanced plasmonic metamaterials.
Controlling the polarization of light with chiral plasmonic nanostructures
Domaines
Nanophysics, nanophotonics, 2D materials and van der Waals heterostructures,, surface physicss, new electronic states of matter
Type of internship
Expérimental
Description
In this project we will (1) locally and electrically excite chiral plasmonic nanoparticles and (2) to use them to enhance the chiral properties of a new class of two-dimensional (2D) semiconductors called transition metal dichalcogenides (TMDCs), which are key for a new branch of physics and technology called valleytronics