SFP Alpes

Jean CAPPELLO (Institut Lumière Matière, Lyon)
2026-01-26 11:00 - 12:00 (Europe/Paris) | LiPhy, Salle de Conférence, 140 rue de la Physique, St Martin d'Hères, 38400
Transport of beads, bubbles and droplets in cylindrical microchannel : The role of inertia and deformations
Abstract :
When transported in microchannels at intermediate Reynolds number, beads, droplets or bubbles show interesting dynamics such as lateral migration. For rigid beads this migration is solely induced by inertial forces which lead to lateral motion of the particle until it reaches an equilibrium uncentered position in the microchannel. Transport of deformable objects as droplets or bubbles is even richer as the coupling between deformation and the external flow results in another lateral migration force whose orientation depends on the viscosity ratio of the two phases. I will present a study in which we investigate, both experimentally and numerically, the velocity and lateral position of beads, droplets and bubbles transported in a cylindrical pipe. By varying the object size, the viscosity ratio, the density, the Reynolds number and the capillary number, we offer an exhaustive parametric study exploring various dynamics from the non-deformable viscous regime to the deformable inertial regime, thus enabling us to highlight the sole and combined roles of inertia and capillary effects on lateral migration. Then, focusing on the specific case of bubbles, we further identify an intriguing regime at large deformations in which bubbles travel faster than the maximum velocity of the carrier flow. We rationalize this behavior in the limit of large bubbles and show that it originates from a reduction of the hydraulic resistance of the multiphase system. Finally, we determine the key parameters governing the onset of this “superfast” regime and demonstrate that it occurs only within a limited range of capillary and Reynolds numbers.
Contact : elise.lorenceau@univ-grenoble-alpes.fr

Juan FONTECILLA-CAMPS (IBS / Groupe Métalloprotéines)
2026-01-27 10:30 - 11:30 | IBS, 71 avenue des Martyrs, Grenoble
Exaptation : la composante opportuniste de l’évolution et de la sélection naturelle
Résumé :
La variété et la capacité fonctionnelle des êtres vivants ont toujours intrigué les biologistes. Le philosophe grec Aristote était, il y a plus de 2300 ans, le premier à classifier les animaux selon la couleur de leur sang. Il croyait aussi que les mêmes animaux avaient existé, immuables, depuis une éternité. Il a fallu attendre le XIXe siècle pour que Charles Darwin explique l’évolution des espèces par la sélection naturelle. Cette évolution peut paraître linéaire et, pour certains, elle aurait un but (téléologie). Mais pour les évolutionnistes il n’y pas de plan ni de finalité. Un des résultats fondamentaux de la sélection naturelle est l’adaptation ; une fois qu’un organe est devenu utile, les mutations aléatoires qui améliorent sa fonction seront sélectionnées parce qu’elles sont avantageuses. Mais la sélection naturelle opère aussi de manière opportuniste, et un organe donné peut se transformer pour remplir une fonction complètement différente de celle d’origine ; c’est l’exaptation. Un cas classique est la transformation d’écailles de dinosaures en plumes d’oiseaux. Pendant mon séminaire je vais illustrer plusieurs cas d’exaptation biologique, et discuter aussi l’exaptation culturelle.
Contact : ibs.seminaires@ibs.fr

Nidia MALDONADO CARMONA (University of Florence, Italy)
2026-01-27 11:00 - 12:00 | IAB – Salle de séminaire, IAB Site Santé - Allée des Alpes, La Tronche, 38700, France
Bringing light to pathogens : light-driven strategies for disinfection of pathogens
Abstract :
The emergence of antimicrobial resistance has prompted the search for new strategies, aiming to find more efficient ways to kill microbial pathogens. In this sense, Photodynamic Antimicrobial ChemoTherapy (PACT) uses a combination of light, oxygen and a photosensitizer molecule to produce lethal reactive oxygen species, which have demonstrated to be highly effective against microorganisms and even against multiresistant microorganisms. During this talk, I will address the different challenges that surround the field, ranging from an efficient delivery of photosensitizers using natural biopolymers, while also addressing the delivery of light into a clinical scenario model, addressing the difficulties of biological experiments with
two-variables to juggle with, technical challenges that hinder the application of this technique into the clinic.
Contact : appaixfl@univ-grenoble-alpes.fr

Juan POLO (Technology Innovation Institute, Abu Dhabi)
2026-01-28 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Static impurity in a mesoscopic system of SU(N) fermionic matter-wavesJuan POLO
Abstract :
We investigate the effects of a static impurity, modeled by a localized barrier, in a one-dimensional mesoscopic system comprised of strongly correlated repulsive SU(N)-symmetric fermions. For a mesoscopic sized ring under the effect of an artificial gauge field, we analyze the particle density and the current flowing through the impurity at varying interaction strength, barrier height and number of components. We find a non-monotonic behaviour of the persistent current, due to the competition between the screening of the impurity, quantum fluctuations, and the phenomenon of fractionalization, a signature trait of SU(N) fermionic matter-waves in mesoscopic ring potentials. This is also highlighted in the particle density at the impurity site. We show that the impurity opens a gap in the energy spectrum selectively, constrained by the total effective spin and interaction. Our findings hold significance for the fundamental understanding of the localized impurity problem and its potential applications for sensing and interferometry in quantum technology.
Contact : pierre.nataf@lpmmc.cnrs.fr

Giovanni FINOCCHIO (University of Messina, Italy)
2026-01-28 11:00 - 12:00 | CEA – Salle de Séminaire IRIG (1005 – 445), Laboratoire Irig/Spintec, salle de séminaire 445, bâtiment 1005, CEA-Grenoble, Grenoble
Adaptive Ising Machines : a paradigm combining oscillatory dynamics and probabilistic sampling
Résumé :
The first part of the talk will focus on probabilistic computing which is one direction to implement Ising Machines with Probabilistic computing that is a computational paradigm using probabilistic bits (p-bits), unit in the middle between standard bit and q-bits. I will show how to map hard combinatorial optimization problems (Max-Sat, Max-Cut, etc) into Ising machine and how to implement those in spintronic technology. I will present new directions in this field considering the concept of extended probabilistic variables such as p-dit and p-int. I will then discuss oscillatory Ising Machines dynamics with the aim of introducing the concept of Adaptive Ising Machines. For doing that, first I will discuss the universal theory of phase auto-oscillators driven by a bi-harmonic signal (having frequency components close to single and double of the free-running oscillator frequency) with noise showing how deterministic phase locking and stochastic phase slips can be continuously tuned by varying the relative amplitudes and frequencies of the driving components. I will then focus on how to use spin-torque nano-oscillators for implementing deterministic, probabilistic computing and dual-mode operation of Adaptive Ising Machines that dynamically combines both regimes within the same hardware platform by properly tuning noise strength and a bi-harmonic excitation. Benchmarking on different classes of combinatorial optimization problems, the CoIM exhibits complementary performance as compared to OIMs and probabilistic Ising machines PIMs, with adaptability to the specific problem class. This work introduces the first oscillator-based Ising machine capable of transitioning between deterministic and probabilistic computation, opening a path toward scalable, CMOS-compatible hardware for hybrid optimization and inference. This work was supported under the project number 101070287 — SWAN-on-chip — HORIZON-CL4-2021-DIGITAL-EMERGING-01, the project PRIN 2020LWPKH7 funded by the Italian Ministry of University and Research and by the PETASPIN association (www.petaspin.com) and it has been also funded by European Union (NextGeneration EU), through the MUR-PNRR project SAMOTHRACE (ECS00000022).
Contact : admin.spintec@cea.fr

Félix PALM (Université Libre de Bruxelles)
2026-01-30 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Quantum Hall states in optical lattices : Revealing hidden long-range
Abstract :
The study of interacting quantum Hall states and their exotic anyonic excitations poses a major challenge in current experimental and theoretical research. Quantum simulators, in particular cold atoms in optical lattices, provide a promising platform to realize, manipulate, and understand such systems with unprecedented control. In this talk, I will discuss how the local resolution of quantum gas microscopes extends the toolbox of quantum Hall physics. To this end, I will discuss a fundamental question regarding the topological order of quantum Hall states: the speculated condensation of composite bosons exhibiting quasi long-range order. I will exemplify this mechanism in bosonic [1] and fermionic [2] systems and touch upon its detectability in tensor network simulations and quantum gas microscopes. If time permits, I will also touch upon the interplay of spin and charge in fermionic quantum Hall states, resulting in ferromagnetism and skyrmionic spin-textures [2,3]. Again, I will present signatures to identify these states in cold-atom quantum simulators. References : [1] Pauw et al., Detecting Hidden Order in Fractional Chern Insulators; PRR 6 (2024) [2] Pauw et al., From hidden order to skyrmions: Quantum Hall states in an extended Hofstadter-Fermi-Hubbard model; arXiv:2509.12184 (2025) [3] Palm et al., Ferromagnetism and skyrmions in the Hofstadter–Fermi–Hubbard model; NJP 25 (2023) Contact : cecile.repellin@lpmmc.cnrs.fr

Sara MATYAS (CNRS Innovation)
2026-02-02 11:00 - 12:00 | LiPhy, Salle de Conférence, 140 rue de la Physique, St Martin d'Hères, 38400
Continuum des financements des projets de valorisation
Résumé :
Les financements de valorisation sont nombreux, chacun avec ses guichets, ses règles et ses critères… Et si on éclaircissait ce sujet ensemble ? À partir d’exemples concrets, nous parcourrons les différents chemins possibles pour valoriser un projet de recherche, depuis l’idée fondamentale jusqu’à sa valorisation. Vous verrez que la start‑up n’est qu’une option parmi d’autres. L’objectif : décoder clairement les informations essentielles à retenir pour chaque type de financement et comprendre la dynamique du continuum (Pré‑maturation CNRS, Pré‑maturation PUI, Maturation SATT, programme RISE, BTF Lab, Incubation, Transfert, Licensing…).
Contact : bahram.houchmandzadeh@univ-grenoble-alpes.fr

Mandar M. DESHMUKH (Tata Institute of Fundamental Research, India)
2026-02-03 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
2D van der Waals Josephson devices
Résumé :
I will discuss two classes of Josephson devices. First, proximitized graphene-based Josephson junctions that are gate tunable. The graphene Josephson FET enables a quantum-noise-limited parametric amplifier with performance comparable to the best discrete amplifiers in this class [1]. One can realize extremely sensitive and fast bolometers [2] – useful for dark matter search, among other applications. Second, twisted van der Waals heterostructures based on the high-temperature superconductor Bi2Sr2CaCu2O8 et δ enable the realization of a high-temperature Josephson diode [3] for the first time. Such Josephson diodes offer an opportunity to realize new devices at liquid nitrogen temperatures. While opportunities abound with vdW JJs, the challenge of scalability must be overcome to translate them into real-world devices.
References :
[1] « Quantum-noise-limited microwave amplification using a graphene Josephson junction » Joydip Sarkar et al. , Nature Nanotechnology 17, 1147 (2022).
[2] “ Kerr non-linearity enhances the response of a graphene Josephson bolometer,” Sarkar et al. , Nature Communications volume 16, 7043 (2025).
[3] « High-temperature Josephson diode, » Sanat Ghosh et al. Nature Materials 23, 612 (2024).

Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr

W. John KAO (Président de l’Université NTHU de Taïwan)
2026-02-03 17:00 - 18:30 | Grenoble INP – Auditorium, UGA, parvis Louis Néel, 38000 Grenoble, Grenoble, 38000, France
Geopolitical and strategic challenges in the semiconductor sector comparative perspectives from NTHU and UGA
Les semi-conducteurs sont aujourd’hui au cœur de la transformation numérique et industrielle mondiale, soulevant des défis majeurs de souveraineté technologique, de compétitivité économique et de sécurité stratégique. Taïwan occupe dans ce contexte une place absolument centrale, tant par son excellence industrielle que par la densité de ses écosystèmes de recherche, de formation et d’innovation, au premier rang desquels figure Hsinchu, véritable épicentre taïwanais des semi-conducteurs. De son côté, Grenoble Alpes, véritable hub de la microélectronique et silicon valley européenne, concentre près d’un quart des emplois français de la filière et abrite de nombreux laboratoires de pointe, soulignant son rôle stratégique à différentes échelles. La présence du Professeur Kao, Président de la NTHU – université de référence mondiale dans ce domaine – apporte un éclairage unique et de tout premier plan sur ces enjeux majeurs.
Cette conférence, d’une durée d’une heure et en langue anglaise, sera animée par la maîtresse de cérémonie, Dr Pauline Ravinet, attachée scientifique et universitaire à l’Office français à Taipei. Elle comprendra une brève présentation de la part de W. John Kao, suivie d’un échange avec Yassine Lakhnech, Président de l’UGA, puis d’une session de questions-réponses avec le public.
Gratuit, sur Réservation
Contact : lou.boucard-pra@unvi-grenoble-alpes.fr

Claude RACINET (Académie Delphinale/RHEOP)
2026-02-05 08:00 - 10:00 | CHU – Salle Gilbert Faure, CHU Grenoble Alpes Pavillon Vercors (côté Belledonne), La Tronche, 38043, France
Nous sommes tous des prématurés
Intervention de Claude RACINET de l’Académie Delphinale et du Registre des Handicaps de l’Enfant et Observatoire Périnatal de l’Isère et de la Savoie (RHEOP).

Contact : sante-communication@univ-grenoble-alpes.fr

Flavien MUSEUR (PSI / ETH Zurich)
2026-02-05 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Artificial spin ice on the CaVO lattice : a bridge from square to kagome
Résumé :
Artificial spin ices are arrangements of dipolar-coupled nanomagnets, with magnetic moments that behave like Ising spins as a result of shape anisotropy. They have been successfully implemented as platforms for imaging and controlling phase transitions in systems with long-range interactions [1]. However, the exploration of thermally-activated phase transitions has been mostly focused on two lattices: the square and the kagome. Artificial square ice orders readily into an antiferromagnetic, two-in/two-out ground state, with a transition belonging to the Ising 2D universality class [2]. In contrast, artificial kagome ice is highly frustrated and the predicted phase diagram is richer [3, 4]. Upon lowering the temperature, the system first experiences a crossover from a paramagnetic to a spin liquid state with no long range order, then transitions into a Coulomb phase with charge crystallization. This is an example of magnetic moment fragmentation [5, 6], in which each magnetic moment can be decomposed into the sum of a long-range ordered, divergence-full fragment and a fluctuating, divergence-free fragment which can be elegantly mapped to a dimer model.
We have carried out a comprehensive characterization of the thermodynamics of an artificial spin ice based on the CaVO (also called the square-octagon) lattice, part of the family of Archimedean lattices [7]. We show that the magnetic interactions on the vertex level can be significantly tuned by changing the relative sizes of square and octagonal plaquettes, while preserving the lattice constant and symmetries. This results in a complex phase diagram, with two very different ground states and ordering processes separated by a multicritical region. Each bears strong similarities with either the square or kagome phenomenologies. We map out this phase diagram with Monte-Carlo simulations and magnetic force microscopy of as-grown configurations. Different spin liquid states can be observed, as well as moment fragmentation for some geometries. Finally, we perform temperature and field-dependant magnetometry measurements on a series of lattice geometries, making it possible to detect thermally-active correlated phases without using large-scale instrumentation. Our work paves the way for engineering exotic magnetic properties at the mesoscale. By tuning frustration within a single lattice geometry, we can design artificial systems that exhibit spin liquid and multicritical behaviours – something that, in natural magnetic systems, typically requires extremes of either pressure, field or temperature.

S. H. Skjærvø et al., Nature Reviews Physics 2, 13–28 (2019).
O. Sendetskyi et al., Physical Review B 99, 214430 (2019).
G. Möller and R. Moessner, Physical Review B 80, 140409 (2009).
G.-W. Chern et al., Physical Review Letters 106, 207202 (2011).
M. E. Brooks-Bartlett et al., Physical Review X 4, 011007 (2014).
B. Canals et al., Nature Communications 7, 11446 (2016).
O. A. Starykh et al., Physical Review Letters 77, 2558–2561 (1996).

Contact : elsa.lhotel@neel.cnrs.fr

Doru C. LUPASCU (Institute for Materials Science and CENIDE - Faculty of Engineering, University of Duisburg-Essen)
2026-02-06 10:30 - 12:30 | ILL – Salle de Séminaire (110-111), ILL 50 71 avenue des Martyrs, Grenoble, 38042, France
Hyperfine Interactions as a Probe in Solids : The Example of a Multiferroic System : Bismuth Ferrite
Hyperfine interactions denote the coupling of the wave functions of nuclear states to the electronic shell of the atom. This coupling is a correction term to the energy of a nuclear state and equally so in reverse manner for the electronic shell of the atom.
Like nuclear magnetic resonance or Mössbaer spectroscopy, the nuclear perturbed gamma-gamma-angular correlation spectroscopy (PAC) investigates this energetic modification of the nuclear state. For sufficiently high nuclear spin value, magnetic interactions as well as quadrupole interactions become accessible. The beauty of the method is its highly local character in the crystal lattice. It directly monitors fields at a particular lattice or defect site. Similar is true for molecules.
Bismuth ferrite is a perovskite crystal exhibiting magnetic and electric ordering phenomena. It is antiferromagnetic and a very good ferroelectric. We used several probe atoms that offer suitable nuclear gamma-gamma cascades to understand these two ordering phenomena in the identical crystal and their coupling. Different from the long term belief, we proved that there is no magnetoelectric coupling in this crystal.
The presentation will introduce the measurement method, and the material system and display how it can be used to investigate solids in a very local manner.
—
Hanno Filter (College 3 Secretary)
External visitors may ask for a site access to tellier(at)ill.fr
Zoom link : https://ill.zoom.us/j/98964195699?pwd=[REDACTED] – Password : [REDACTED]

Kei YAMAMOTO (Advanced Science Research Center, Japan)
2026-02-06 11:00 - 12:00 | CEA – Salle de Séminaire IRIG (1005 – 445), Laboratoire Irig/Spintec, salle de séminaire 445, bâtiment 1005, CEA-Grenoble, Grenoble
Spin-wave spectrum in a ferromagnetic disk
Abstract :
Angular momentum transfer in all forms contributes to the loss of information carried by dynamical spin polarisations and constitutes an important fundamental problem in spintronics. In this talk, we present a detailed microwave spectrum measurement of magnetic excitations in an Yttrium Iron Garnet disk, and how one can make sense of the multitudes of spectral lines and their magnetic field dependence theoretically. We explain how the axial symmetry of the setup leads to labelling of modes in terms of the conserved total angular momentum of the spin waves, The frequency spectrum in the saturated state is compared to analytical solutions for pure exchange as well as pure dipolar models under certain limits where different types of spectral degeneracy occur. The experimental result shows splittings of those degenerate modes, and we discuss possible interpretations in relation to angular momentum transfer between its different forms.
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More information :https://www.spintec.fr/seminar-spin-wave-spectrum-in-a-ferromagnetic-disk/​​​
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Visioconference :https://univ-grenoble-alpes-fr.zoom.us/j/98769867024?pwd=[REDACTED]​​

William FAUGNO (LKB / Collège de France)
2026-02-06 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Quantum Many-Body Scars in the Presence of Density-Difference-Dependent Hopping
Résumé :
It has been observed that isolated quantum systems often still produce measured values consistent with thermalization. This is unexpected due to the lack of a notion of chaos or ergodicity and the unitary dynamics of the quantum theory which is at its core linear. The conditions under which we can expect isolated quantum systems to thermalize were laid out in the eigenstate thermalization hypothesis (ETH), which has generally been found to hold in a variety of systems. Still, notable violations of the ETH have been identified where a seemingly chaotic many-body quantum system exhibits some nonthermal behavior. In this talk, I will introduce the concept of quantum many-body scars (QMBS), a phenomenon in which a small subset of eigenstates violates the ETH and promote nonthermal dynamics. I will then present theoretical results on a bosonic Hamiltonian with a density-dependent hopping and describe two distinct mechanisms for scar formation that arise in this model. These mechanisms provide insight into the conditions under which QMBS can be expected to occur.
Contact : serge.florens@neel.cnrs.fr

David SKURNIK (Hôpital Necker- Enfants Malades, Université Paris Cité)
2026-02-06 11:00 - 12:00 | IBS – Salle des séminaires, IBS 71 avenue des Martyrs, Grenoble, 38042, France
New approaches in vaccine development
Résumé :
High-throughput sequencing and particularly original applications such as the TnSeq allow a study of host-pathogen interaction at the full genome scale through a systematic analysis off all the virulence factors of a bacteria in a particular setting. For example, all the genes important or essential for GI tract colonization of the selected pathogenic bacteria.
This allows to reveal new targets for vaccine development. Interestingly, an ongoing adaptation of the TnSeq allows the systematic identification of these antigens of interest. We call this new technology : TnVaccine.
Contact : ibs.seminaires@ibs.fr

Isidora ARAYA DAY (DIPC San Sebastian)
2026-02-09 11:00 - 12:00 | LPMMC – salle Roger Maynard (G421), CNRS - LPMMC 25 avenue des Martyrs, Grenoble, 38042, France
Diagnosing higher order topological phases with electronic transport
Résumé :
Unlike a quantum Hall bar, a higher-order topological insulator may not have edge modes that conduct, but localized corner modes. These corner modes are robust to disorder and their appearance is diagnosed by a topological invariant that takes both onsite and spatial symmetries. In this talk, I will introduce a scattering theory for detecting higher-order topological phases only from a sample’s Fermi level properties, and will demonstrate how to apply it to different models. This theory provides an alternative approach for proving bulk–edge correspondence in intrinsic higher order topological phases, especially in presence of disorder, and it relies on the spectral flow that these phases show in the presence of magnetic flux.
Contact : serge.florens@neel.cnrs.fr

Stéphanie ROCCIA (LPSC-CNRS/UGA, Grenoble)
2026-02-10 10:30 - 11:30 | ILL – Salle de Séminaire (110-111), ILL 50 71 avenue des Martyrs, Grenoble, 38042, France
The search for neutron electric dipole moment at PSI
Résumé :
The Universe and its history are simultaneously very well understood and still a big mystery. We have amazing tools from satellites to
observatories to weight the universe over its history. But the components of the Universe can simply not yet be explained by physicists. To get the full picture, we need to identify and understand the interactions at play throughout the life of the Universe. This is the meeting point between particle physics and cosmology. At this meeting point stands the neutron, a common particle that we can uniquely use in high precision experiments.
I will present how experiments searching for a permanent electric dipole moment of the neutron (nEDM) aim at discovering new sources of CP violation beyond the Standard Model of particle physics and understanding the origin of the matter-antimatter asymmetry of the Universe. The quest for the neutron electric dipole moment started more than sixty years ago. In recent experiments, polarized ultra-cold neutrons are stored in material bottles.
I will present the ongoing efforts at the Paul Scherrer Institute in Switzerland where the n2EDM spectrometer has taken the first “physics data” in 2025. A large fraction of this dataset is dedicated to measurements of the UCN spectrum. I will present the newest UCN spectroscopy techniques that were recently published and the reasons for the importance of a deep understanding of the UCN spectrum.
—
Hanno Filter (College 3 Secretary)
External visitors may ask for a site access to tellier(at)ill.fr
Zoom link : https://ill.zoom.us/j/98964195699?pwd=[REDACTED] – Password : [REDACTED]

Delphine ROPERS (Inria – Grenoble)
2026-02-12 13:00 - 14:00 | IMAG – Salle de Réunion, 150 place du Torrent, St Martin d’Hères, 38400, France
Computational analyses of bacterial mRNA decay

Plus d’informations : https://bi-gre.github.io/
Contact : lucie.lamothe@univ-grenoble-alpes.fr

Youngsuk KIM (Pusan National University, Busan, South Korea (visiting scientist @ DCM))
2026-02-12 14:00 - 15:00 | DCM – Salle C209, DCM - Bât Chimie Recherche 301 rue de la Chimie, St Martin d'Hères, 38400, France
Carbene–CS2 : Redox-active Radical Ligands
Contact : david.martin@univ-grenoble-alpes.fr

Roxane LESTINI & Nicolas OLIVIER (Laboratoire d'Optique et Biosciences, Palaiseau)
2026-02-16 11:00 - 12:00 | LiPhy, Salle de Conférence, 140 rue de la Physique, St Martin d'Hères, 38400
Understanding DNA replication dynamics in the archaea Haloferax volcanii
Résumé :
Archaea provide a simplified yet highly informative model for deciphering the complex regulatory networks governing DNA replication and origin firing. Among them, Haloferax volcanii has a circular chromosome with four active replication origins distributed across a 3.5 Mb DNA molecule and exhibit some distinctive properties, such as a heterogeneous polyploidy, carrying 10–18 copies of its genome.
How these highly polyploid organisms regulate the activation and timing of their multiple replication origins in coordination with cell growth and division remains an open question. To address this question, we developed a multiscale approach, implementing the STORM technique in archaea for the first time, Marker Frequency Analysis by sequencing (MFA-seq) to capture the global replication profile at the population level, and fluorescence in situ hybridization (FISH) to explore ploidy variation.
Our findings reveal, with an unprecedented resolution of ~30 nm, new insights into the spatial regulation of replication foci, demonstrating their organization into clusters. We further investigated DNA replication dynamics under varying growth conditions, revealing a reduction in replication foci number that correlates with decreased replication rates and DNA content. By contrast, altering the replication initiation mode—by inactivating all four replication origins—does not disrupt the overall replication dynamics.
By integrating these techniques, we aim to characterize the replication program in H. volcanii and gain a deeper understanding of its regulation.
Contact : delphine.debarre@univ-grenoble-alpes.fr

Igor ROZHANSKIY (National Graphene Institute, University of Manchester)
2026-02-17 14:00 - 15:00 | CEA – Salle de Séminaire IRIG (1005 – 445), Laboratoire Irig/Spintec, salle de séminaire 445, bâtiment 1005, CEA-Grenoble, Grenoble
Interacting spin physics in 2D : flat bands, SOC renormalization, and chiral textures
Résumé :
Two-dimensional materials and their heterostructures offer a controllable setting where exchange, spin-orbit coupling (SOC), and electron interactions shape the spin-resolved electronic structure and response. This seminar links two recent directions of my work through this common theme.
The first part focuses on van der Waals magnets (chromium trihalides) combined with graphene. Narrow, spin-polarized conduction bands make these systems susceptible to charge-transfer-driven doping and strong correlations. Using DFT-calibrated effective tight-binding models, I will show how flat-band features and longer-range hopping processes determine the low-energy spectrum and favor regimes with heavy, strongly interacting carriers.
​ The second part addresses many-body renormalization of SOC in monolayer transition metal dichalcogenides. Exchange effects can enhance the conduction-band spin-orbit splitting in a density-dependent manner. I will outline ​the underlying mechanism and discuss how it can be inferred from gated transport and quantum-oscillation measurements, including multilayer configurations where valley structure and interlayer coupling provide additional diagnostics.
A short outlook will touch on chiral spin textures, such as skyrmions, and how real-space chirality can contribute to transverse signals, emphasizing possible connections and open questions for 2D material platforms.
https://www.cea.fr/drf/irig/Pages/Animation-scientifique/seminaires/2026_Rozhanskiy.aspx
Contact : admin.spintec@cea.fr

Anton POTOCNIK (IMEC, Belgium)
2026-02-17 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
High-coherence foundry-compatible superconducting qubit platform
Résumé :
The field of superconducting qubit technology has experienced rapid development over the past two decades. Recent advancements in the fabrication, control and measurement of superconducting quantum devices have enabled integration of hundreds of qubits on a single chip. However, the path towards larger-scale integration of thousands of qubits on a chip remains unclear. This talk presents imec’s platform for scalable superconducting qubit fabrication, which is based on foundry-compatible thin film processing 1 and overlay Josephson-junction fabrication 2. The platform enables all-optical superconducting transmon qubit fabrication on 300 mm wafers, achieving near state-of-the-art coherence times, record-low aging and comparable Josephson junction variability to standard shadow-evaporation technique 3. A key focus of this presentation will be the understanding and mitigation of microwave losses induced by various fabricaiton steps such as Ar-milling 4 and oxide removal 6,7 and materials such as -Ta 5 or ultra-high-resistivity silicon. The talk will conclude with an outline of ongoing efforts toward large-scale qubit characterization and control using cryo-CMOS electronics operating near qubits at the mixing-chamber plate of a dilution refrigerator 8.
1 Mongillo, et al., IEDM (2022).
2 Verjauw et al., npj Quantum Information 8, 93 (2022).
3 Van Damme, et al., Nature, 634, 74 (2024).
4 Van Damme, et al., PRA 20, 014034 (2023).
5 Lozano, et al. Mater. Quantum. Technol. 4, 025801 (2024).
6 Verjauw, et al., PRA 16, 014018 (2021).
7 Lozano, et al., Advanced Science 12, e09244 (2025).
8 Acharya, et al., Nature Electronics, 6, 900 (2023).
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Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr

Francesco ROSA (Politecnico di Milano, Italy)
2026-02-17 14:00 - 15:00 | CNRS – Salle Louis Weil (E424), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
Magnetic and orbital properties of infinite-layer nickelate and cuprate superconductors
Résumé :
Infinite-layer (IL) nickelates recently gained strong interest thanks to their apparent analogies with cuprates, including a square lattice-based structure dominated by superexchange antiferromagnetic interaction and the emergence of superconductivity upon hole doping. X-ray spectroscopies with synchrotron light are a very powerful tool for the investigation of such systems, providing complementary information to the more traditional inelastic neutron scattering. In this seminar, we discuss some of the recent results obtained by our group using both Resonant Inelastic X-ray Scattering (RIXS) and X-ray Magnetic Circular Dichroism (XMCD), mainly focusing on magnetism. RIXS results concern the analysis of dynamic spin excitations (magnons/paramagnons), investigating the effect of hole-doping on them and providing an estimate for the magnetic exchange coupling constants. Results on IL nickelates will be compared to analogous ones on cuprates, highlighting analogies and differences. XMCD analysis is devoted to the static spin order in IL nickelates, reporting the presence of a field induced out-of-plane Ni1+ spin moment. Based on magnetic field- and temperature-dependent measurements, we justify our observations with an out-of-plane canting of in-plane anti-ferromagnetically correlated Ni1+ spins, tentatively attributed to a symmetry lowering of the NiO2 planes.
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Contact : andrew.fefferman@neel.cnrs.fr

Sharlen MOORE (Johns Hopkins University, Baltimore, USA)
2026-02-19 11:30 - 12:30 | GIN – Amphi Serge Kampf, Grenoble Institut des Neurosciences (GIN) Bât. Edmond J. Safra, Chemin Fortune Ferrini CHU, La Tronche, 38700, France
Revealing abrupt transitions from goal-directed to habitual behavior
Résumé :
A fundamental tenet of animal behavior is that decision-making involves multiple ‘controllers.’ Initially, behavior is goal-directed, driven by desired outcomes, shifting later to habitual control, where cues trigger actions independent of the motivational state. Clark Hull’s question from 1943 still resonates today: “Is this transition [to habit] abrupt, or is it gradual and progressive?” Despite a century-long belief in gradual transitions, this question remains unanswered as current methods cannot disambiguate goal-directed versus habitual control in real time. Here, we introduce a novel ‘volitional engagement’ approach, motivating animals by palatability rather than biological need. Providing less palatable water in the home cage reduced motivation to ‘work’ for plain water in an auditory discrimination task compared to water-restricted animals. Using quantitative behavior and computational modeling, we found that palatability-driven animals learned to discriminate as quickly as water-restricted animals but exhibited state-like fluctuations when responding to the reward-predicting cue-reflecting goal-directed behavior. After thousands of trials, these fluctuations spontaneously and abruptly ceased, with animals always responding to the reward-predicting cue. In line with habitual control, post- transition behavior displayed motor automaticity, decreased error sensitivity (assessed via pupillary responses), and insensitivity to sensory-specific outcome devaluation. Bilateral lesions of the habit-related dorsolateral striatum (DLS) blocked transitions to habitual behavior. Finally, we used bilateral fiber photometry in the putative controllers of goal-directed (dorsomedial striatum, DMS) and habitual (DLS) behavior to monitor the evolution of neural activity across learning. Both the DMS and DLS exhibited learning- related signatures in cue, lick, and outcome-related signaling at similar timescales in parallel. Immediately after transitioning to habitual behavior, outcome-related signaling was suppressed in the DLS and, to a lesser extent, in the DMS, while cue-evoked responses further sharpened. This abrupt shift (reduction in outcome signaling and sharpening of cue-evoked responses) suggests that sensory cues rather than outcomes drive habitual responding. Our results demonstrate that both controllers (DMS and DLS) exhibit learning-related plasticity in parallel but that the behavioral manifestation of habits emerges spontaneously and abruptly in a DLS-dependent manner, suggesting the involvement of a higher-level process that arbitrates between the two.
Contact : robin.magnard@univ-grenoble-alpes.fr

Dmitri KHVESHCHENKO (University of North Carolina)
2026-02-20 11:00 - 12:00 | LPMMC, CNRS - Bat G, salle Roger Maynard G-421, Grenoble
Applied Hall-o-graphy with no strings attached
Résumé :
This discussion aims at ascertaining the true status of the so-called applied-holographic approach to strongly correlated quantum matter. The latter ranges from ‘not even wrong’ for the constructions based on the ad hoc ‘AdS/CMT’ to ‘might be right, albeit for the wrong reason’ for those emerging in the context of phase-space bosonization and the related ‘Hall-o-graphic’ hydrodynamics.The presentation will be made accessible to the wide audience of non-experts and students.
Contact : serge.florens@neel.cnrs.fr

Mourad CHABBI (docteur en sciences politiques, GEM / « Géopolitique ») & Ludivine CALAMEL (professeur Senior en sciences de gestion, GEM)
2026-02-20 12:30 - 13:15 | Amphi Minatec, 3 parvis Louis Néel, Grenoble, 38054, France
L’impact du contexte géopolitique sur l’évolution des règles et du marché des semi-conducteurs
Résumé :
Cette conférence s’intéresse à la manière dont le contexte géopolitique impacte les organisations, et notamment certaines gravitant dans le domaine de la micro-électronique (semi-conducteurs).
Contact : giant.campus@cea.fr

Sophie Abby (TIMC, Grenoble)
2026-02-24 18:30 | Museum de Grenoble, 1 Rue Dolomieu, Grenoble, 38000, France
Le premier souffle : comment les microbes ont oxygéné la Terre
Résumé :
Cette soirée explore la diversité du vivant à travers l’arbre phylogénétique, en s’appuyant sur les travaux du projet Quinevol qui étudie les quinones, molécules essentielles présentes dans tous les organismes vivants. Comment les organismes primitifs respiraient-ils avant l’apparition de l’oxygène ? Comment se sont-ils ensuite adaptés à ce qui était alors un véritable poison ? Un voyage scientifique des origines de la vie jusqu’aux frontières de la recherche actuelle.

Céline SCORNAVACCA (ISEM – Montpellier)
2026-02-26 13:00 - 14:00 | IMAG – Salle de Réunion, 150 place du Torrent, St Martin d’Hères, 38400, France
A New Algorithm for Computing the Likelihood of a Phylogeny
Contact : lucie.lamothe@univ-grenoble-alpes.fr

Paulo Henrique MACIEL BUZZETTI (Département de Chimie Moléculaire, équipe I2BM (nouvel entrant))
2026-02-26 14:00 - 15:00 | DCM – Salle C209, DCM - Bât Chimie Recherche 301 rue de la Chimie, St Martin d'Hères, 38400, France
From Bio-analytics & Bio-energy : A Journey Through Functional Interfaces & Supramolecular Architectures
Contact : quentin.laurent@univ-grenoble-alpes.fr

Rolf LORTZ (CNRS-LNCMI, Grenoble)
2026-02-26 14:00 - 15:00 | CNRS – Salle Rémy Lemaire (K223), CNRS - Institut Néel 25 avenue des Martyrs, Grenoble, 38042, France
High temperatures superconductivity with giant pressure effect in 3D networks of boron doped ultra-thin carbon nanotubes in the pores of ZSM-5 zeolite
Résumé :
We report the fabrication of three‑dimensional, interconnected networks of ultrathin carbon nanotubes (CNTs) embedded within the ~5 Å pores of zeolite ZSM‑5 crystals using a controlled chemical vapour deposition (CVD) process. Confinement within these sub‑nanometre channels yields CNTs with strongly one‑dimensional electronic characteristics, including pronounced van Hove singularities in the density of states. By introducing boron dopants during growth, we strategically tune the Fermi level toward a van Hove singularity, as supported by ab initio electronic‑structure calculations. This electronic tuning, combined with the intrinsic 3D connectivity of the CNT–zeolite framework, enables a dimensional crossover from 1D electronic states to a phase‑coherent, bulk superconducting state.
To establish the presence of superconductivity, we employ five complementary experimental probes—electrical resistivity, ac susceptibility, dc magnetization, specific heat, and point‑contact spectroscopy. All measurements consistently indicate a superconducting transition at ambient pressure with a critical temperature Tc in the range of 220–250 K. Simultaneous resistivity and ac‑susceptibility measurements reveal a three‑order‑of‑magnitude drop in resistance accompanied by the onset of a robust Meissner effect with nearly perfect diamagnetic screening. Point‑contact spectroscopy further uncovers a multigap superconducting state, with a dominant gap of approximately 30 meV, in reasonable agreement with expectations from Bardeen–Cooper–Schrieffer (BCS) theory. The differential conductance spectra exhibit clear particle–hole symmetry and evolve smoothly between the tunnelling and Andreev reflection regimes as the contact transparency is varied—behaviour uniquely characteristic of superconducting quasiparticles. Specific‑heat measurements show a distinct anomaly at the transition, reminiscent of signatures observed in high‑Tc cuprate superconductors.
Finally, we find that the application of very modest external pressure further enhances the superconducting transition temperature, pushing Tc above ambient temperature and suggesting that the system remains far from its optimal tuning point. These results collectively point to a new pathway for achieving high‑temperature superconductivity in engineered low‑dimensional carbon‑based materials.
Contact : florence.levy-bertrand@neel.cnrs.fr
