The solid-state systems, presently considered for quantum computation, are built from localized two-level systems, prime examples are superconducting qubits or semiconducting
quantum dots. Due to the fact that they are localized, they require a fixed amount of hardware per qubit.
Propagating or “flying” qubits have distinct advantages with respect to localised ones: the hardware footprint depends only on the gates and the qubits themselves (photons) can be created on demand making these systems easily scalable. A qubit that would combine the advantages of localised two-level systems and flying qubits would provide a paradigm shift in quantum technology. In the long term, the availability of these objects would unlock the possibility to build a universal quantum computer that combines a small, fixed hardware footprint and an arbitrarily large number of qubits with long-range interactions. A promising approach in this direction is to use electrons rather than
photons to realise such flying qubits. The advantage of electronic excitations is the Coulomb interaction, which allows the implementation of a two-qubit gate.
The aim of the present Phd will be the development of the first quantum-nanoelectronic platform for the creation, manipulation and detection of flying electrons on time scales down to the picosecond and to exploit them for quantum technologies.
Measuring quantum decoherence and entanglement in attosecond photoemission
The PhD project is centered on the advanced study of attosecond photoemission dynamics. The objective is to access in real time decoherence processes induced, e.g., by electron-ion quantum entanglement. To that aim, the young researcher will develop attosecond spectroscopy techniques making use of a new high repetition rate Ytterbium laser.
Detailed summary :
In recent years, there has been spectacular progress in the generation of attosecond (1 as=10-18 s) pulses, awarded the 2023 Nobel Prize [1]. These ultrashort pulses are generated from the strong nonlinear interaction of short intense laser pulses with gas jets [2]. They have opened new prospects for the exploration of matter at the electron intrinsic timescale. Attosecond spectroscopy allows studying in real time the quantum process of photoemission and shooting the 3D movie of the electron wavepacket ejection [3, 4]. However, these studies were confined to fully coherent dynamics by the lack of experimental and theoretical tools to deal with decoherence and quantum entanglement. Recently, two techniques have been proposed to perform a quantum tomography of the photoelectron in its final asymptotic state [5, 6].
The objective of the PhD project is to develop attosecond spectroscopy to access the full time evolution of decoherence and entanglement during the photoemission process. Quantum tomographic techniques will be implemented on the ATTOLab laser platform (https://iramis.cea.fr/en/lidyl/atto/attolab-platform/) using a new Ytterbium laser source. This novel laser technology is emerging, with stability 5 times higher and repetition rate 10 times higher than the current Titanium:Sapphire technology. These new capabilities represent a breakthrough for the field and allow, e.g., charged particle coincidence techniques, to study the dynamics of photoemission and quantum entanglement with unprecedented precision.
This PhD project is performed in the frame of a recently funded European Network QU-ATTO (https://quatto.eu/), providing an advanced training to 15 young researchers, and opening many opportunities of joint work with European laboratories. In particular, strong collaborations are already ongoing with the groups of Prof. Anne L’Huillier in Lund, and Prof. Giuseppe Sansone in Freiburg. Due to the Mobility Rule, candidates must not have resided (work, studies) in France for more than 12 months since August 2022.
The student will receive solid training in ultrafast optics, atomic and molecular physics, attosecond science, quantum optics, and will acquire a broad mastery of XUV and charged-particle spectroscopy techniques.
References :
[1] https://www.nobelprize.org/prizes/physics/2023/summary/
[2] Y. Mairesse, et al., Science 302, 1540 (2003)
[3] V. Gruson, et al., Science 354, 734 (2016)
[4] A. Autuori, et al., Science Advances 8, eabl7594 (2022)
[5] C. Bourassin-Bouchet, et al., Phys. Rev. X 10, 031048 (2020)
[6] H. Laurell, et al., Nature Photonics, https://doi.org/10.1038/s41566-024-01607-8 (2025)
Synthesis of biosourced alkanes from fatty acid methyl ester
Alkanes or hydrocarbons are essential molecules in the energy sector (fuels) as well as in specialty chemistry (cosmetics, adhesives, etc.) and fine chemistry. Today, they are primarily derived from non-renewable fossil resources that are not available at the national scale and contribute to climate change. To reduce the carbon footprint and enhance energy independence, the efficient production of hydrocarbons from renewable and available sources such as biomass is an attractive alternative.
This thesis project focuses on developing innovative methods to produce bio-based hydrocarbons from fatty acid methyl ester (FAME). The primary objective is to extrude carbon dioxide from FAME in a single catalytic step, using light as a renewable energy source. The project is structured into two parts: the first aims to verify the compatibility of catalytic systems for breaking the C–O bond with photocatalytic decarboxylation processes, while the second focuses on recombining alkyl residues to synthesize hydrocarbons.
By contributing to reducing dependence on fossil fuels and lowering greenhouse gas emissions, the thesis project aligns with the strategy of diversifying energy sources.
Development and study of laminated composite material with carbon nanotubes functionalisation dedicated to launcher linerless cryogenic tank
The use of composite materials in the space field has led to great weight improvements. To continue to achieve significant weight gain, composite cryogenic tank is the next technological application to reach by replacing the current metal alloy cryogenic propellant tanks. Lighter reinforced organic matrix composite materials (that are at least as efficient from a mechanical, thermal, chemical and ignition resistance point of view) are a realistic target to be reached that has been explored in recent years. Many research approaches tend to answer to this technological lock, but the potentialities of Carbon NanoTubes (CNTs) in terms of mechanical and physical properties, need to be explored deeper.
A first phase to assess the interest of CNTs for space applications (collaboration CNES/CEA/I2M/CMP Composite) was carried out to associate CNTs with a cyanate ester matrix in layered composite materials through three processes: (i) transfer of aligned CNTs mats by hot pressing (ii) dispersion of entangled CNTs mixed with resin, or (iii) growth of nanotubes aligned directly on the dry ply. Knowing mechanical and thermal loads, the aim is to demonstrate the efficiency of CNTs and influence of their characteristics with regard to damage tolerance of the material and consist in delaying the cracking process of the composite nearby the CNT layer and thus blocking the percolation of the cracking network which leads to the loss of tightness. For the preferred development process identified, the aim of this doctoral work is now to consolidate the material functionalisation with CNTs (shape, density, etc.) and the understanding of the mechanical behaviour (at room temperature and at low temperature) for the development of the layered material integrating CNTs.
Knowing the potential final application as cryogenic tank or for the improvement of structural materials sustainability in dual application, relevant tests will be performed to demonstrate the impact in terms of damage development and tightness in comparison with the same material without CNTs.
Alternatives to perfluorinated compounds for water-repellent and oil-repellent treatments of textiles used for NRBC personal body protection
Finding alternatives to fluorinated compounds (PFAS) involves very diverse application areas. Among them, the treatment of technical textiles to make them water- and oil-repellent is a major challenge for manufacturing protective clothing against both aqueous and oily contaminants. Our laboratory is developing such alternatives by covalently grafting molecules onto fibers selected from those already used for technical textiles. The thesis will focus on experimental work with two components. The first component will consist of improving and qualifying, at a semi-industrial level, the water- and oil-repellent properties already obtained and qualified according to current standards (water and oil droplet sliding, slow impregnation of oil droplets) using our nanometric chemical coatings. The second component will be dedicated to optimizing the weave structure, in conjunction with the chemical treatment, to determine the optimal weave based on the desired properties. The work will be carried out in close contact with a technical textile manufacturer and with ENSAIT in Roubaix.
Radiological large-scale accident dosimetry: use of EPR spectroscopy for population triage by measurements of smartphone screens
In the event of a large-scale radiological emergency involving sources of external irradiation, methods are needed to identify which members of the population have been exposed and require priority care. To date, there are no operational methods for such sorting. Smartphone touch screen lenses retain traces of ionizing radiation through the formation of so-called “radiation-induced” defects.Measuring and quantifying these punctual defects, in particular by electron paramagnetic resonance (EPR) spectroscopy, makes itpossible to estimate the dose deposited in the glass, and thus the exposure associated with irradiation. The thesis work proposed herefocuses in particular on the alkali-aluminosilicate glasses used in cell phone touch screens, which are currently the best candidates fordeveloping new measurement capabilities in the context of accidents involving large numbers of victims.
We will focus in particular on identifying point defects as a function of the glass model used in smartphones by simulating EPR spectra in order to optimize the proposed dosimetry method.
Wetting dynamics at the nanoscale
Wetting dynamics describes the processes involved when a liquid spreads on a solid surface. It's an ubiquitous phenomenon in nature, for example when dew beads up on a leaf, as well as in many processes of industrial interest, from the spreading of paint on a wall to the development of high-performance coating processes in nanotechnology. Today, wetting dynamics is relatively well understood in the case of perfectly smooth, homogeneous model solid surfaces, but not in the case of real surfaces featuring roughness and/or chemical heterogeneity, for which fine modeling of the mechanisms remains a major challenge. The main goal of this thesis is to understand how nanometric roughness influences wetting dynamics.
This project is based on an interdisciplinary approach combining physics and surface chemistry. The PhD student will conduct systematic model experiments, combined with multi-scale visualization and characterization tools (optical microscopy, AFM, X-ray and neutron reflectivity, etc.).
Thanks to the complementary nature of the experimental approaches, this thesis will provide a better understanding of the fundamental mechanisms of energy dissipation at the contact line, from the nanometric to the millimetric scale.
Understanding the signals emitted by moving liquids
Elasticity is one of the oldest physical properties of condensed matter. It is expressed by a constant of proportionality G between the applied stress (s) and the deformation (?): s = G.? (Hooke's law). The absence of resistance to shear deformation (G' = 0) indicates liquid-like behavior (Maxwell model). Long considered specific to solids, shear elasticity has recently been identified in liquids at the submillimeter scale [1].
The identification of liquid shear elasticity (non-zero G') is a promise of discoveries of new solid properties. Thus, we will explore the thermal response of liquids [2,3], exploit the capacity of conversion of mechanical energy into temperature variations and develop a new generation of micro-hydrodynamic tools.
At the nanoscopic scale, we will study the influence of a solid surface in contact with the liquid. It will be a question of studying by unique methods such as Inelastic Neutron Scattering and Synchrotron radiation, the dynamics of the solid-liquid interface using Very Large Research Facilities such as the ILL or the ESRF, as well as by microscopy (AFM). Finally, we will strengthen our collaborations with theoreticians, in particular with K. Trachenko of the Queen Mary Institute "Top 10 Physics World Breakthrough" and A. Zaccone of the University of Milan.
The PhD topic is related to wetting, macroscopic thermal effects, phonon dynamics and liquid transport.
Development and characterization of a reliable 13.5 nm EUV OAM carrying photon beamline
The Extreme UltraViolet (EUV) photon energy range (10-100 nm) is crucial for many applications spanning from fundamental physics (attophysics, femto-magnetism) to applied domains such as lithography and nanometer scale microscopy. However, there are no natural source of light in this energy domain on Earth because photons are strongly absorbed by matter, requiring thus vacuum environment. People instead have to rely on expensive large-scale sources such as synchrotrons, free electron lasers or plasmas from large lasers. High order laser harmonic generation (HHG), discovered 30 years ago and recognized by the Nobel Prize in Physics in 2023, is a promising alternative as a laboratory scale EUV source. Based on a strongly nonlinear interaction between an ultrashort intense laser and an atomic gas, it results in the emission of EUV pulses with femto to attosecond durations, very high coherence properties and relatively large fluxes. Despite intensive research that have provided a clear understanding of the phenomenon, it has up to know been mostly limited to laboratories. Breaching the gap towards applied industry requires increasing the reliability of the beamlines, subjects to large fluctuations due to the strong nonlinearity of the mechanism, and developing tools to measure and control their properties.
CEA/LIDYL and Imagine Optic have recently joined their expertise in a join laboratory to develop a stable EUV beamline dedicated to metrology and EUV sensors. The NanoLite laboratory, hosted at CEA/LIDYL, is based on a high repetition rate compact HHG beamline providing EUV photons around 40eV. Several EUV wavefront sensors have been successfully calibrated in the past few years. However, new needs have emerged recently, resulting in the need to upgrade the beamline.
The first objective of the PhD will be to install a new HHG geometry to the beamline to enhance its overall stability and efficiency and to increase the photon energy to 92eV, a golden target for lithography. He will then implement the generation of a EUV beam carrying orbital angular momentum and will upgrade Imagine Optic’s detector to characterize its OAM content. Finally, assisted by Imagine Optic engineers, he will develop a new functionality to their wavefront sensors in order to enable large beam characterization.
Advanced characterization of ferroelectric domains in hafnia-based thin films
Les mémoires ferroélectriques à accès aléatoire (FeRAM en anglais) à base d'oxyde d’hafnium et de zirconium (HZO) sont intrinsèquement ultra-faibles en consommation grâce au mécanisme de changement de tension, au potentiel de mise à l'échelle du HZO en dessous de 10 nm et à la compatibilité CMOS complète. De plus, elles présentent une faible latence nécessaire à une grande variété d'applications de logique et de mémoire. La compréhension des mécanismes sous-jacents et de la cinétique du ‘switching’ des domaines ferroélectriques est essentielle pour une conception intelligente des FeRAMs avec des performances optimales.
Cette thèse porte sur la caractérisation complète des domaines ferroélectriques (FE) dans des films HZO ultra-minces. L'étudiant utilisera plusieurs techniques d'imagerie de surface (microscopie à force piézoélectrique, PFM, microscopie électronique à basse énergie, LEEM, et microscopie électronique à photoémission de rayons X, PEEM) combinées à des méthodes avancées de caractérisation operando (détection résolue dans le temps couplée au rayonnement synchrotron). Ce projet marquera une avancée importante dans la recherche fondamentale des mécanismes de basculement de polarisation des couches FE ultra-minces à base d'hafnium, en élucidant les effets spécifiques de l'interface électrode métallique/couche FE dans le comportement électrostatique des condensateurs étudiés. Il permettra à terme une avancée significative dans le développement industriel des mémoires émergentes ferroélectriques, essentielles pour les applications d'intelligence artificielle (IA) à grande échelle.