Dimensionality reduction method applied to the deformed coupled cluster ab initio many-body method
The theoretical description from first principles, i.e. in a so-called ab initio manner, of atomic nuclei containing more than 12 nucleons has only recently become possible thanks to the crucial developments in many-body theory and the availability of increasingly powerful high-performance computers. These ab initio techniques are successfully applied to study the structure of nuclei, starting from the lightest isotopes and now reaching all medium-mass nuclei containing up to about 80 nucleons. The extension to even heavier systems requires decisive advances in terms of storage cost and computation time induced by available many-body methods. In this context, the objective of the thesis is to develop the dimensionality reduction method based on the factorization of tensors involved in the non-perturbative many-body theory known as deformed coupled cluster (dCC). The proposed work will exploit the latest advances in nuclear theory, including the use of nuclear potentials from chiral effective field theory and renormalization group techniques, as well as high-performance computing resources and codes.
Magneto-mechanical stimulation for the selective destruction of pancreatic cancer cells while sparing healthy cells
A novel approach for selectively destroying cancer cells is being developed through a collaboration between the BIOMICS biology laboratory and the SPINTEC magnetism laboratory, both part of the IRIG Institute. This method employs magnetic particles dispersed among cancer cells, which are set into low-frequency vibration (1–20 Hz) by an applied rotating magnetic field. The resulting mechanical stress induces controlled cell death (apoptosis) in the targeted cells.
The effect has been demonstrated in vitro across various cancer cell types—including glioma, pancreatic, and renal cells—in 2D cultures, as well as in 3D pancreatic cancer spheroids (tumoroids) and healthy pancreatic organoids. These 3D models, which more closely mimic the structure and organization of real biological tissues, facilitate the transition to in vivo studies and reduce reliance on animal models. Preliminary findings indicate that pancreatic cancer cells exhibit a higher affinity for magnetic particles and are more sensitive to mechanical stress than healthy cells, enabling selective destruction of cancer cells while sparing healthy tissue.
The next phase will involve confirming this specificity in mixed spheroids (containing both cancerous and healthy cells), statistically quantifying the results, and elucidating the mechanobiological mechanisms underlying cell death. These promising findings pave the way for an innovative biomedical approach to cancer treatment.
Multi-Probe Cosmological Mega-Analysis of the DESI Survey: Standard and Field-Level Bayesian Inference
The large-scale structure (LSS) of the Universe is probed through multiple observables: the distribution of galaxies, weak lensing of galaxies, and the cosmic microwave background (CMB). Each probe tests gravity on large scales and the effects of dark energy, but their joint analysis provides the best control over nuisance parameters and yields the most precise cosmological constraints.
The DESI spectroscopic survey maps the 3D distribution of galaxies. By the end of its 5-year nominal survey this year, it will have observed 40 million galaxies and quasars — ten times more than previous surveys — over one third of the sky, up to a redshift of z = 4.2. Combining DESI data with CMB and supernova measurements, the collaboration has revealed a potential deviation of dark energy from a cosmological constant.
To fully exploit these data, DESI has launched a “mega-analysis” combining galaxies, weak lensing of galaxies (Euclid, UNIONS, DES, HSC, KIDS) and the CMB (Planck, ACT, SPT), aiming to deliver the most precise constraints ever obtained on dark energy and gravity. The student will play a key role in developing and implementing this multi-probe analysis pipeline.
The standard analysis compresses observations into a power spectrum for cosmological inference, but this approach remains suboptimal. The student will develop an alternative, called field-level analysis, which directly fits the observed density and lensing field, simulated from the initial conditions of the Universe. This constitutes a very high-dimensional Bayesian inference problem, which will be tackled using recent gradient-based samplers and GPU libraries with automatic differentiation. This state-of-the-art method will be validated alongside the standard approach, paving the way for a maximal exploitation of DESI data.
Origins and evolution of prion-like proteins (PrLPs) in eukaryotes
Initially associated with neurodegenerative diseases, prion-like proteins (PrLPs) are now recognized as key physiological players in cellular plasticity and stress response. These proteins often contain an intrinsically disordered domain rich in glutamine and asparagine, known as a prion-like domain (PrLD), capable of switching between soluble, condensed, or amyloid states. Notable examples include CPEB in Aplysia, involved in synaptic memory, MAVS in antiviral defense, MED15 and FUS in transcriptional regulation and nucleocytoplasmic condensate dynamics, and ELF3 in plants, whose amyloid polymerization controls flowering and photoperiodic responses. In fungi, Sup35, Ure2p, and HET-s serve as experimental models of functional prions, demonstrating that reversible aggregation can act as a regulatory or adaptive mechanism. These conformational transitions are now viewed as adaptive molecular strategies rather than pathological anomalies.
This PhD project aims to trace the origin and diversification of prion-like proteins across eukaryotes, testing the hypothesis that major paleoclimatic crises have episodically promoted the emergence and duplication of genes encoding PrLDs through microsatellite expansion and transposable element activity. The project will combine large-scale phylogenomic analyses, PrLD domain detection, and modeling of selective pressures to map the key stages in the functional evolution of PrLPs and their links to stress tolerance.
Exotic shape of the nucleus: decay spectroscopy of neutron-deficient actinides with the detector SEASON
The question of the limit of stability of nuclei, both in terms of proton/neutron asymmetry and in terms of mass, is an important open question in modern nuclear physics. In the region of heavy nuclei, the neutron-deficient actinides present a great interest. Indeed, strong octupolar deformation, giving a pear shape to the nuclei, are predicted and have event been already observed in some isotopes. These deformations seem to play a key role for nuclear stability, for nuclear decay modes, and may also be related to physics beyond the standard model. The main goal oh this thesis will be to pursue the systematic study of these deformations by making use of the brand-new SEASON detector, whose first experiment will take place at the University of Jyväskylä (Finland) in February 2026. The thesis will focus on the analysis of data from the experimental campaign that will occur in summer 2026. Several experiments are foreseen, making use of different beam-target combinations to produce actinides by fusion-evaporation reaction. These actinides will then be sent inside SEASON to perform their decay spectroscopy. Depending on the plannings, another campaign could be scheduled at Jyväskylä in 2027. Finally, the return of the instrument in France to be set up at GANIL-Spiral2 (Caen) coupled to the S3 spectrometer will certainly take place this the thesis period.
The thesis can be co-directed by the university of Jyväskylä.
Endothelial-fibroblast interactions in diabetic foot ulcer: deciphering the intercellular communication responsible for the chronic wound persistence
Diabetic foot ulcer (DFU), a severe complication of diabetes affecting approximately 18.6 million people worldwide each year, is associated with high rates of amputation and mortality. Like other chronic wounds, DFUs exhibit impaired healing due to a dysregulated cascade of cellular signalling and behavioural events that normally ensure rapid closure of the skin barrier. Among the key cellular players, fibroblasts and endothelial cells are central to the proliferative and remodelling phases of wound repair – processes that are notably dysfunctional in chronic wounds. Although endothelial-fibroblast crosstalk is recognized as an essential driver of normal skin healing, the specific mechanisms governing their interaction in DFU is poorly understood.
The main objective of this PhD project is to decipher the intercellular communication between endothelial cells and fibroblasts that underlies the chronicity of DFU. Particular attention will be devoted to extracellular vesicle-associated microRNAs (miRNAs), which are pivotal regulators of intercellular communication through modulation of gene expression in recipient cells. By characterizing the repertoire of pro- and anti-healing miRNAs exchanged between endothelial cells and fibroblasts, this project seeks to uncover novel molecular targets and therapeutic strategies to promote wound repair in diabetic foot ulcers.
Surface technologies for enhanced superconducting Qubits lifetimes
Materials imperfections in superconducting quantum circuits—in particular, two-level-system (TLS) defects—are a major source of decoherence, ultimately limiting the performance of qubits. Thus, identifying the microscopic origin of possible TLS defects in these devices and developing strategies to eliminate them is key to superconducting qubit performance improvement. This project proposes an original approach that combines the passivation of the superconductor’s surface with films deposited by Atomic Layer Deposition (ALD), which inherently have lower densities of TLS defects, and thermal treatments designed to dissolve the initially present native oxides. These passivating layers will be tested on 3D Nb resonators than implemented in 2D resonators and Qubits and tested to measure their coherence time. The project will also perform systematic material studies with complementary characterization techniques in order to correlate improvements in qubit performances with the chemical and crystalline alteration of the surface.
https://iramis.cea.fr/lidyl/pisp/150720-2/
Recent advances in ultrafast optics and the control of highly nonlinear light–matter interactions now make it possible to generate attosecond light pulses (1 as = 10?¹8 s) through High-Order Harmonic Generation (HHG). This process converts a femtosecond laser pulse into coherent, ultrashort radiation in the extreme ultraviolet (XUV) range (10–150 eV). These unique light sources enable access to electronic dynamics on sub-femtosecond timescales and allow the probing of element-specific transitions that were previously only achievable at large-scale facilities such as synchrotrons. The Attophysics Group at LIDYL, a pioneer in the generation, characterization, and application of attosecond pulses, has recently developed sources driven by beams carrying spin (SAM) or orbital (OAM) angular momentum, opening new avenues for studying chiral and magnetic dynamics. Building on these advances, this PhD project aims to synthesize light fields with time- and space-dependent chirality, exploiting in particular the often-neglected longitudinal component of the electric field. Three regimes will be explored: a linear regime (XUV/IR pump–probe), a strongly nonlinear regime (structured visible–IR fields in chiral samples), and a weakly nonlinear regime (IR pump/XUV probe). This work will open a new class of attosecond physics experiments, bridging fundamental exploration and emerging applications.
The student will acquire practical knowledge about lasers, in particular femtosecond lasers, and hands on spectrometric techniques of charged particles. They will also study strong field physical processes which form the basis for high harmonic generation. They will become an expert in attosecond physics. The acquisition of analysis skills, computer controlled experiments skills will be encouraged although not required.
Details at https://iramis.cea.fr/lidyl/pisp/150720-2/
Monitoring criticality risk through neutron noise in degraded nuclear environments
Our team at CEA/Irfu is working with ASNR to study the possibility of using neutron noise measurements, i.e., stochastic variations in neutron flux, to estimate the reactivity of subcritical nuclear systems. The aim is to propose this technique for online measurement of the reactivity of the corium at Fukushima Daiichi during future decommissioning operations. The thesis work will focus on evaluating a solution based on Micromegas-type neutron detectors (nBLM detectors) developed by IRFU, which are adapted to the extreme gamma radiation expected in the vicinity of the Fukushima Daiichi corium. The student will participate in experiments at nuclear research facilities in Europe and the United States to test this technical solution and measure neutron noise for a wide range of reactivities. He/she will be responsible for analyzing the data and evaluating the various inversion methods used to estimate reactivity from neutron noise measurements.
Stabilization and pharmacological characterization of engineered ß-Amyloid oligomers for diagnostic and therapeutic innovation in Alzheimer’s disease
Alzheimer’s disease (AD) is the leading cause of dementia worldwide, yet its molecular mechanisms remain poorly understood. Numerous studies have shown that soluble oligomers of the amyloid-ß peptide (Aß1-42) are the earliest and most toxic forms in the amyloid cascade, responsible for initial neuronal damage prior to plaque formation. However, their intrinsic instability makes them difficult to study.
This project aims to design stable analogues of the Aß peptide capable of organizing into well-defined oligomeric forms, particularly tetramers and octamers. These species will be structurally and pharmacologically characterized to better understand their neurotoxic effects and interactions with neuronal membranes.
Fluorescent probes developed in the laboratory will enable the tracking of these species in cellular models and in vivo, through a collaboration with Dr. Nadja Van Camp (MIRCen).
The expected results will help identify the Aß forms truly responsible for neurodegeneration, pave the way for more selective therapeutic strategies, and support the development of innovative approaches for the early diagnosis of Alzheimer’s disease.