2026 UniGe Physics day

Thursday 8 Jan 2026, 08:15 → 20:30 Europe/Zurich

MS150 (UniMail )

To facilitate scientific discourse and promote social interaction within the physics section, we are excited to announce a one-day Physics meeting scheduled for January 8, 2026, running from 8:30 AM to 6:00 PM. This special event is designed to engage every member of the section, offering young researchers a platform to showcase their projects in a clear and jargon-free manner, fostering accessible and engaging discussions for all.

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08:30 → 09:00 Coffee and tea

09:00 → 09:25 Welcome

09:25 → 10:43 Presentations: Morning 1

09:25 TBD DQMP

Senior Talk DQMP

Speaker: Prof. Fabian von Rohr

09:43 The dynamical structure of the Earth climate: implications for its trajectory under the current climate change

During the last 1 million years, Earth's climate has been paced by the glacial-interglacial cycle, characterized by alternating climate conditions, especially the appearance and disappearance of massive ice sheets in North America and Eurasia. These oscillations between warm (inter-glacial) and cold (glacial) states raise concerns about the potential existence of a `hot' state that could result from the Earth's climate trajectory under the current climate change. In our approach, this could be explained by the particular dynamical structure of the Earth climate and its different co-existing climate steady states (attractors).

To tackle this question, we construct the bifurcation diagram of the Earth climate as a function of the CO$_2$ concentration between 100 ppm and 560 ppm to cover the inter-glacial/glacial oscillations and the potential Earth's climate future trajectory. We analyze the stability range of each attractor and their tipping points. In addition, some particular tipping elements that can collapse/disappear (as the Atlantic Meridional Oceanic Circulation, the Greenland ice sheet, etc.) are detailed to determine the potential existence of hysteresis and irreversible behavior.

This analysis is performed using a newly developed coupled setup, biogeodyn-MITgcmIS, which employs the MIT general circulation model as its dynamical core, and offline couples vegetation, hydrology and ice sheets. For evaluating future climate trajectories, it is therefore important to consider the long-term adaptation of vegetation, hydrology and ice sheet dynamics over millennial time scales.

Speaker: Laure Moinat (Group of Applied Physics and Institute for Environmental Sciences, University of Geneva, Geneva, Switzerland)

09:55 Never Too Late For New Physics with ATLAS Experiment at LHC

My research focuses on the search of New Physics with hadrons arriving late to the ATLAS calorimeter.
This talk will explain why signatures with unusually timed final states compared to the SM particles are a promising avenue for discovering New Physics. It will also discuss the unique backgrounds that this search must address, especially those arising from interactions between the beam and the LHC’s own material.

Speaker: Lucas Bezio (Universite de Geneve (CH))

10:07 Magnetic field driven re-entrant superconductivity in infinite layer nickelates

We explore the synthesis and emergent electronic behavior of infinite-layer nickelate thin films (112 phase), focusing on Nd1-xEuₓNiO2 (NENO). The infinite layer superconducting phase is obtained from perovskite nickelates via a topotactic reduction, as demonstrated by D. Li [1] using CaH2 or NaH to selectively remove apical oxygens and induce a square planar NiO2 coordination. Following the solid-state route proposed by W. Wei [2,3], we deposit metallic aluminium onto a perovskite film and use the reaction 2Al + 3NdNiO3 → Al2O3 + 3NdNiO2 to obtain the 112 phase. All thin films were synthesized via RF off-axis magnetron sputtering, with the aluminum layer deposited in situ on-axis.

Using high-quality 113 nickelate films and heterostructures [4,5,6], the 112 NENO phase on LSAT and NdGaO3 (NGO) substrates respectively were successfully obtained. The interplay between the field response of the Eu²⁺ and Nd3+ magnetic ions and superconductivity in these infinite-layer systems was investigated.

The lower-Tc samples display a striking re-entrant superconducting behavior and distinct superconducting domes in the Hc2-Tc magnetic phase diagram are observed, consistent with the Jaccarino–Peter effect [7] linked to the negative exchange field between the magnetic rare earth ions and electron spins. The presented Hall effect data can be successfully modeled by including an anomalous Hall term proportional to the spin paramagnetic response of the aforementioned magnetic ions.

References:

[1] D. Li et al., Nature 572, 624-627 (2019)

[2] W. Wei et al., Physical Review Materials 7, 013802 (2023)

[3] W. Wei et al., Sci. Adv. 9, eadh3327 (2023)

[4] C. Domìnguez et al., Nat. Mater. 19, 1182–1187 (2020)

[5] L. Varbaro et al. APL Mater. 12, 081120 (2024)

[6] L. Varbaro et al., Adv. El. Mater. 9, 2201291 (2023)

[7] V. Jacca

Speaker: Lucia Varbaro

10:19 Detecting neutrinos with 2-million plastic cubes

Neutrinos are the the most elusive among the known elementary particles, and for this reasson remain one of the mysterious pieces of the Standard Model. Today we know that the three neutrino flavours mix with each other through a quantum interference effect known as neutrino oscillations.
Since the discovery of the neutrino oscillations, one of the most interesting questions has been whether neutrino oscillation violates CP symmetry, which has important implications for cosmological models. This is studied by observing the oscillation of accelerator-produced neutrinos and antineutrinos over long distances.
T2K (Tokai to Kamioka) is an experiment sited in Japan that studies the phenomenon of neutrino and anti-neutrino oscillation over a distance of 295 km. It is of crucial importance in T2K to characterize the unoscillated neutrino flux (close to the neutrino beam generation point) with a Near Detector. In particular, the near detector is needed to constrain cross section uncertainties in neutrino-nucleus interactions, which will be a limiting factor for the measurement of neutrino oscillation parameters. T2K recently upgraded its near Detector with the addition, among other detectors, of a 2-tonnes neutrino active target named "Super Fine-Grained Detector" (SuperFGD). The SuperFGD is composed of about two-million 1-cm optically isolated plastic scintillator cubes. Scintillation light from the cube is read out by about 56-thousand channels from three directions through wavelength-shifting fibers and photo sensors. It provides 3D track reconstruction, 4$\pi$ angular acceptance, calorimetry, and detection capability of neutrons and low energy protons. This contribution reports the construction and performances of the SuperFGD, as well as the first physics results.

Speaker: Lorenzo Giannessi (University of Geneva)

10:31 Deep Learning Reconstruction on Crab LST-1 Data

The Cherenkov Telescope Array Observatory (CTAO) is the next-generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy. The Large-Sized Telescope prototype, LST-1, located on the Canary Island of La Palma, is responsible for observation of the low-energy range of the VHE gamma-ray spectrum. It is undergoing commissioning and has already observed the Crab Nebula as a standard reference source. Accurate reconstruction of shower parameters (e.g. energy, direction, and particle type) is crucial for achieving the scientific goals of the CTAO. In this work, we use CTLearn to implement deep-learning event reconstruction, as an alternative to the standard Random Forest method. CTLearn is built to be fully compatible with ctapipe, a framework for prototyping the low-level data processing algorithms for the CTAO, and can be seamlessly used for data analysis without changing the general framework. It implements convolution-neural-network based models that take the integrated charge and the relative peak time of calibrated pixels in cleaned images as an input, to infer the primary particle's properties. Using Crab Nebula observations as a validation sample, we explore two different approaches. The first is to train a model with Monte-Carlo (MC) simulations covering all possible altitude-azimuth coordinates of the Crab Nebula sample observations, resulting in a single model that can be used to reconstruct events from any Crab Nebula observations. The second approach is to train 10 models along this coordinate line, each incorporating a range of \textasciitilde10° in altitude. In this contribution, we present our investigation of the performance of CTLearn models, and highlight the potential of CTLearn for future data analysis in the CTAO.

Speaker: BASTIEN LACAVE (Université de Genève)

10:43 → 11:15 Coffee break

11:15 → 12:51 Presentations: Morning 2

11:15 TBD DPT

Senior Talk DPT

Speaker: Prof. Daniel Pierce

11:33 Single-particle spectral function of a fractional Chern insulator using exact diagonalization

This thesis investigates the potential use of the single-particle spectral function as a tool to charac-
terize fractional Chern insulators (FCIs). In particular we have computed the momentum-resolved
spectral function A(k,ω) for a FCI phase realized by a toy model on a Kagome lattice at 1/3
filling. To tackle this problem, we used an exact diagonalization code on a finite-size system
with periodic (twisted) boundaries. We find that the FCI spectrum exhibits a sharp momentum-
independent quasihole peak and a broad particle excitation continuum, both separated by a spec-
tral gap. These features distinguish it from competing charge-ordered states, such as a charge
density wave (CDW), which was also computed during this project in order to have a point of
reference. This result suggests that the spectral function could be used as a probe for topological
order in strongly correlated lattice systems.

Speaker: Vincent Lombardo (DQMP)

11:45 The Universe as testbed of gravity

Testing gravity is challenging because gravity is the weakest of all fundamental forces of nature. Cosmology studies the largest scales accessible to the human being, with gravity being the driving force of cosmic evolution. Therefore, the Universe provides an ideal testbed of gravity. In this talk, I will describe my research on testing general relativity and searching for new gravitational physics with various cosmological probes.

Speaker: Gen Ye (University of Geneva)

11:57 Advancing Gamma-Ray Polarimetry with the POLAR-2 Mission

Gamma-Ray Bursts (GRBs) are among the most energetic events in the universe that have still open questions regarding their jet structure, magnetic-field geometry, and radiation mechanisms; polarization measurements are key to answering these questions. POLAR-2 is an improved version of its predecessor POLAR, and aims to measure the polarization of GRBs within a higher energy range of 30-800 KeV and with a much higher effective area thanks to its design. The instrument is constructed from 100 polarimeter modules each consisting of 8 × 8 array of rectangular plastic scintillator bars in which Compton-scattering events are reconstructed to measure the photon polarization. The scintillation light is read out using state-of-the-art silicon photomultipliers coupled through a novel optical interface which reduces the optical cross-talk between the scintillators. The interactions of the gamma-rays in the detector are simulated with Geant4, and the output of this simulation is passed to a digitization Monte Carlo (MC) to be converted to an ADC signal. An engineering qualification model (EQM), consisting of 3 × 3 polarimeter modules, is currently being assembled to validate and finalize the detector design. Moreover, a dedicated Module Analysis Framework has been developed to analyze calibration data, extract physical inputs for Geant4 modelling, and validate the simulation pipeline. To this effect, a major calibration campaign is scheduled for February 2026 at the European Synchrotron Radiation Facility (ESRF) to characterize the polarimetric response of the EQM. Upon completion of the EQM phase, POLAR-2 will proceed to full production and is scheduled for launch in early 2028 to China Space Station, where it will deliver unprecedented GRB polarisation measurements.

Speaker: Mobin Mobaseri (University of Geneva)

12:09 Extending low mass dark matter searches using Trigger Level Analysis at the ATLAS Experiment

Traditional searches for new physics at the ATLAS experiment can be limited by the finite trigger bandwidth and storage capacity for LHC collision data. The ATLAS trigger determines which data to discard and selects only a small fraction of events for further analysis. In order to study events that are typically rejected by the trigger ATLAS has introduced a new real-time data analysis technique: Trigger Level Analysis (TLA). TLA provides a huge increase in statistics as the memory footprint of each collision decreases from around 1MB to 6.5kB per event.
This facilitates the search for new physics in previously unexplored regions of phase space and increases the sensitivity reach to dark matter models with low masses and couplings. This contribution introduces TLA in ATLAS for LHC Run 3 and presents its potential applications.

Speaker: Leon Bozianu (University of Geneva)

12:21 Lattice electrons in large magnetic fields

The most common way of studying electrons in a lattice is to imagine that they simply hop instantaneously from one lattice site to another. When a magnetic field is involved, it is common to assume that the only way, in which it affects the electrons, is by attaching a gauge-dependent phase shift to their hops. This assumption, however, is only valid for relatively small magnetic field strengths. There are also well-established theories for when the magnetic field is very large, but they deal with very weak periodic potentials. In this work, we focus on two-dimensional systems and theoretically study the intermediate regime where both magnetic fields and periodic confining potentials are strong, thus, bridging the gap between the two limiting cases. We study the geometry of the wavefunctions and show that there are multiple topological phase transitions between the two limiting cases. Furthermore, we demonstrate how hopping models can be made more realistic in the presence of large magnetic fields.

Speaker: Ivo Gabrovski (DQMP, UniGe)

12:33 Physiscope

Physiscope and repairlab

Speaker: Dr Céline Lichtensteiger

12:51 → 14:00 Lunch

14:00 → 15:30 Presentations: Afternoon 1

14:00 Quantum network technology — The second life of rare-earth crystals

Speaker: Prof. Wolfgang Tittel

14:18 Spectro-temporal laser scanning for video rate volumetric two-photon imaging

Multi photon scanning microscopy gives access to high axial resolution, high penetration depth and
the third spatial dimension at the cost of imaging speed as each pixel must be probed individually.
The image acquisition time of conventional scanning systems is inertia limited by the oscillation
frequency of two galvanometric mirrors, making observation of biological processes that occur in
three-dimensional space on a milli second timescale inaccessible.
We present the prototype in development of a mobile, small footprint Spectro-Temporal Laser
Imaging by Diffractive Excitation (SLIDE) system that aims to overcome this limitation. This multi-
photon scanning microscope utilizes a fast tunable Fourier Domain Mode Locking (FDML) Laser with
a center wavelength of 1065 nm and a pulse repetition rate up to 1 GHz in combination with a
diffractive element to achieve frame rates of up to 1.8 kHz and live volume imaging of a 250
x 250 x 100 μm³ volume with a volume rate of up to 20 volumes per second.
At these scanning speeds, corresponding to a pixel dwell time of ~1.2 ns each pixel only gets excited
a single time per acquisition, limiting the photon budget. We compare this Imaging modality to a
conventional multi photon system and demonstrate its feasibility for in vitro and in vivo imaging.

Speakers: Moritz Wiggert, Thomas Krähenbühl (Unige, GAP) , Dr Alexandra Latshaw (GAP NBI) , Prof. Luigi Bonacina (GAP NBI)

14:30 LACTEL: a cosmic-ray detector in the Lac Léman

The LACTEL project proposes the development of a Water Cherenkov Detector Array (WCDA) for cosmic electron and gamma-ray observations, through the study of Extensive Air Showers (EAS).
It aims to improve gamma-ray and electron observations above 10 TeV, suppressing the hadron background through muon tagging.
Additionally, the project will also serve as a multidisciplinary platform for optical water property studies and luminous phenomena in alpine lakes.

The detector consists of several light-tight water tanks floating on the lake. Each tank accommodates a photomultiplier tube to detect the Cherenkov light produced by the charged particles of the showers.
The elementary cell of such a detector is composed of two stacked tanks: the upper one serves as a conventional WCD to detect the shower electromagnetic component, the lower one acts as a muon and hadron detector.
Repurposed optical modules from the ANTARES neutrino detector, decommissioned in 2022, will be used.

Three water tank prototypes have been installed in the Lac Léman, within the LéXPLORE research platform.
The LACTEL scientific purpose, design, and results of the first prototype tests will be presented in this contribution.

Speaker: Ettore Zaffaroni (DPNC)

14:42 The Terzina Cherenkov Telescope Onboard NUSES Space Mission: Simulation Framework, Sensor Characterisation, and Expected Performance

The Terzina payload aboard the NUSES mission is being developed by GSSI, INFN, and the University of Geneva in collaboration with Thales Alenia Space–Italy. It is a compact Cherenkov Schmidt–Cassegrain telescope with a 925 m effective focal length and a 640-pixel SiPM focal plane composed of FBK 8 × 8 tiles, designed to observe Cherenkov light from extensive air showers produced by ultra-high-energy cosmic rays and Earth-skimming neutrinos. A comprehensive simulation chain has been developed, combining CORSIKA and EASCherSim shower generation with a detailed Geant4 optical model of the telescope, together with realistic modelling of the trigger logic and SiPM response. This integrated simulation framework, supported by laboratory characterisation of the sensors and implemented through modular C++ modules and Python reconstruction tools, provides a realistic performance assessment of Terzina and is adaptable to future high-altitude or balloon-borne Cherenkov telescopes. We present the expected performance above a few hundred PeV and discuss the main challenges of operating SiPMs in space, including radiation-induced increases in dark count rate, luminous background contributions, and optimisation of the data acquisition strategy to maximise effective exposure.

Speaker: Shideh Davarpanah (Université de Genève)

14:54 β-decay spectroscopy studies with spin-polarised neutron-rich nuclei at CERN-ISOLDE

β-decay spectroscopy is a powerful technique for studying the properties of exotic neutron-rich nuclei and improving our understanding of exotic nuclear phenomena, such as β-delayed neutron emission [1-3], relevant in astrophysical r-process.
Thanks to the high angular momentum selectivity of the process, β-decay offers unique access to excited states in daughter nuclei having configurations similar to the decaying precursors. However, the one major drawback of conventional β-decay experiments is the limited ability to firmly assign spins and parities of states involved in the decay [4]. This difficulty can be overcome by employing beams of spin-oriented nuclei. For such nuclei – having a directional orientation of the nuclear spins with respect to the axis of an applied magnetic field - asymmetric emission of β-particles can reveal spins and parities of nuclear states involved in allowed transitions. The unique information obtained from β-decay studies with spin-polarised nuclei can be then used to answer critical questions about βn emitters involved in r-process nucleosynthesis.
This novel approach to β-decay experiments, pioneered by a group from the University of Osaka [5,6], has recently been adopted at the ISOLDE facility at CERN. A new decay-spectroscopy station has been developed and integrated with the VITO beamline [7], which is the permanent setup for laser-induced spin polarisation. The new station, called “DeVITO”, allows coincident measurements of β-delayed radiation emitted from laser-polarised nuclei and, thus, for the selection of the levels of interest for the unambiguous assignment of spins and parities.
The new setup was recently commissioned with beams of neutron-rich potassium isotopes, including strong β-delayed neutron emitters [8]. In particular, measurements with a 47K beam demonstrated the capability of DeVITO to measure β-decay asymmetry in coincidence with γ-rays. This also served as a first demonstration of the application of this novel technique at CERN-ISOLDE, which brings exciting opportunities for further developments in β-decay studies.
In this contribution, details on the new experimental setup, as well as preliminary results from the commissioning runs [9] will be presented.

[1] Z. Xu, R. Grzywacz et al., Phys. Rev. Lett. 133, 042501 (2024).
[2] Z. Y. Xu, M. Madurga et al., Phys. Rev. Lett. 131, 022501 (2023).
[3] V. H. Phong et al., Phys. Rev. Lett. 129, 172701 (2022).
[4] B. Singh et al., Nuclear Data Sheets 84, 487 (1998).
[5] H. Miyatake et al., Phys. Rev. C 67, 014306 (2003).
[6] H. Nishibata et al., Phys. Rev. C 99, 024322 (2019).
[7] M. Kowalska et al., Phys. G: Nucl. Part. Phys. 44, 084005 (2017).
[8] M. Piersa-Siłkowska and N. Azaryan, CERN EP Newsletter, September 2024. https://ep-news.web.cern.ch/content/isoldes-new-β-decay-station-unlocks-advanced-decay-spectroscopy-experiments-laser
[9] M. Piersa-Siłkowska, M. Madurga, M. Kowalska et al., CERN-INTC-2023-026; INTC-P-662.

Speaker: Ilaria Michelon (University of Geneva (CH))

15:06 Topological Defects in Nemato-Polar Systems

Topological defects play a central role in shaping the structure, dynamics, and emergent behaviour of active matter systems. In soft matter physics, the nature of these defects is dictated by the symmetry of the underlying field description: polar systems support integer-charged defects (±1), while nematic systems—with head-tail symmetry—admit half-integer charges (±½). Active matter, particularly in biological and synthetic active nematics, has traditionally been modelled using purely nematic symmetry, where ±½ defects, their creation, annihilation, and dynamics governs the large-scale flows and macroscopic behaviour of the system. However in the physical world, active materials a vast variety of systems — such as epithelial tissues, bacterial colonies — often exhibit mixed symmetries, where polar and nematic components coexist and interact. This mixed structure enriches the defect landscape: polar distortions can bias the orientation or motility of ±½ nematic defects, alter defect unbinding dynamics, and affect defect shape and motion as a result of the underlying coupled fields. Understanding how these different symmetries interplay is essential for detailed hydrodynamic description of active matter.

Speaker: Yuv Agarwal (University of Geneva)

15:18 DAMPE's Silicon-Tungsten tracKer: 10 years anniversary overview

The Silicon-Tungsten tracKer (STK) is part of the Dark Matter Particle Explorer experiment. Launched 10 years ago, it has been operating smoothly ever since, measuring cosmic and gamma rays at high energies in a sun-synchronous orbit. Partly designed and built at the DPNC in Geneva, it has been closely monitored by the local research team since its launch. This monitoring provides key information on the detector's current status, including temperature, noise, and alignment, and is essential for providing precise calibration parameters used during in-flight data collection. Today, STK data is a key input for DAMPE's results and has enabled precise track measurements through a deep-learning track reconstruction tool developed in Geneva.

Speaker: Hugo Boutin

15:30 → 16:00 Coffee break

16:00 → 17:30 Presentations: Afternoon 2

16:00 The exploration of the Universe with multi-messengers

The universe contains a large amount of radiation, from radio waves to gamma rays. At the highest energy end of the radiation spectrum, powerful cosmic accelerators originate it. Their way of functioning and accelerating particles is a very fascinating relativistic laboratory where matter is often in extreme conditions. We will describe different signals with different messengers (gamma rays, neutrinos, and cosmic rays and their relation to gravitational waves), which help understand these accelerators and cataclysmic events in the Universe and the instruments we build for this.

Speaker: Prof. Teresa Montaruli (Département de Physique Nucléaire et Corpusculaire)

16:18 Constraining the Epoch of Reionization with Fast Radio Bursts

Previous works on constraining the Epoch of Reionization (EoR) using FRBs have been done, but they all assume that the redshift at which the FRB is emitted is known. This is possible in principle but requires localization of the FRBs. This can’t be provided by the radio telescopes that detect most FRBs, so it would require a second measurement. My work makes it computationally feasible to constrain the EoR with FRBs without assuming redshift information. To do this I created an emulator that outputs the Dispersion Measure probability distribution given a redshift and a set of theoretical parameters that model the EoR. The Dispersion Measure is the only observable provided by an FRB detection. It’s a proxy for the number of electrons along its path. I used simulations from 21cmFAST to obtain the probability distributions on a grid, then interpolated between fits of these distributions, to extend this to a continuum of parameters. This allows a hierarchical Bayesian inference given a set of measured FRBs. The next steps for this project are to write a Hamiltonian Monte Carlo algorithm to perform the Bayesian inference for different sets of simulated FRBs, to determine how many are needed, and from what redshift, to accurately constrain reionization. We also intend to explore how some redshift information (a feasible amount of it) could improve these predictions. This pipeline could then be used with real data, and could also provide, for example, a precise measurement of the Macquart relation, with error bars.

Speaker: William Paty (UNIGE Physics)

16:30 Neutrinos in a Crowded Nucleus: From Multi-Nucleon Knockout to Oscillations

Multi-nucleon (2p2h, two-particle–two-hole) knockout, in which a neutrino interacts with a correlated pair of nucleons inside a nucleus, is a major source of systematic uncertainty in long-baseline neutrino oscillation experiments. One or more outgoing nucleons may fail to exit the nucleus or fall below detector thresholds and thus remain unobserved. These partially reconstructed events can mimic other reaction channels and bias the reconstructed neutrino energy, with direct consequences for oscillation measurements. Most event generators (simulation tools) currently treat this channel with approximate particle kinematics. Recent theoretical developments, however, provide more complete exclusive predictions that expose limitations of these approximations.

This talk presents multi-nucleon knockout mechanisms with an emphasis on two-nucleon emission, and reports the first dedicated analysis of one such exclusive prediction based on the Valencia model. We identify observables whose kinematic distributions deviate most strongly from the approximations used so far and highlight where current simulations can be improved. Finally, we discuss the prospects for making these observables experimentally accessible in current detectors, focusing on ND280 at the T2K experiment, and outline possible paths towards incorporating more realistic multi-nucleon dynamics in future generator implementations.

Speaker: Vedantha Srinivas Kasturi (University of Geneva)

16:42 Future Viability of European Vineyards using Climate Analogues Methodology

The impacts of climate change on viticulture are a matter of increasing concern, particularly in Europe, where vine-growing is intrinsic to both the economy and cultural heritage. To facilitate a more profound understanding of climate change, the climate analogue method is employed to analyse the case of European vineyards. The methodology consists in matching future vineyard climates with the current one of other regions, providing insights into how shifting climates may influence the suitability of current and potential vineyard regions. The use of the climate analogue method facilitates the identification of regions within Europe that will retain their suitability for viticulture under future climate conditions, whilst concomitantly enabling the discovery of new areas with wine-growing potential in the future.
We introduce a problem-specific approach to climate analogues, considering microclimatic variation and sector-specific climate metrics. Instead of the raw outputs of the climate models, we rely on several bioclimatic indices, that consider climate conditions in the context of vineyard growth and disease development. In order to reduce the variable redundancy, a Principal Component Analysis is applied to these six indices. Furthermore, vineyards are frequently situated in hilly regions with south-facing slopes to maximise sunlight exposure. These topographic characteristics modify temperature, thereby influencing vine growth and disease dynamics. Therefore, we calculate sub-grid local temperature corrections based on slope orientation and altitude.
The findings of this study offer a clearer picture of how European viticulture will need to adapt to climate change, with a particular focus on spatial shifts in suitable regions. This will assist winegrowers in making informed decisions regarding vineyard locations, cultural management strategies, and future investments in viticulture. Our results also demonstrate the importance of using problem-specific indices, handling variable interdependence, and accounting for fine-scale climatic variability in climate analogue analyses. Though developed for viticulture, the methodology and insights are broadly applicable to other climate-sensitive systems, from agriculture to urban planning.

Speaker: Héloïse Allaman

16:54 Molten-Metal Flux Synthesis as a Tool Towards New Quantum Materials

Molten-Metal Flux Synthesis is a well-established synthetic approach, in which single-crystal growth is facilitated by dissolving high-melting metals in low-melting ones. It has been proven as a fruitful method for the formation of metastable or kinetically stabilized phases, which would otherwise be unattainable by conventional solid-state methods. Layered chromium-chalcogenide based quantum materials are of particular interest due to their rich magnetism and strong electronic correlations. We systematically explore the engineering of alkali-chromium-telluride flux reactions to obtain large single-crystals of Delafossite-type $A$CrTe$_{2}$ (A = alkali cation) phases as well as previously unreported $A_{2.4}$Cr$_{8}$Te$_{14}$ compounds, which combine the structural architecture of layered $A$CrTe$_{2}$ phases and tunnelled $A$Cr$_{5}$Te$_{8}$ Hollandite-likes. Beyond the synthetic work, we determine their magnetic properties and their spin structure. Their diverse magnetism in combination with their layered structure make them ideal candidates for future spintronic devices

Speaker: Kai Roeseler

17:06 Measurement of the cosmic-ray boron, carbon and oxygen spectra and the B/C, B/O, C/O flux ratios with the DAMPE space mission

Secondary cosmic ray (CR) measurements offer essential insights into galactic particle propagation mechanisms and interaction processes.
When primary CRs (e.g., carbon and oxygen nuclei) interact with the interstellar medium (ISM), they produce lighter secondary particles through fragmentation.
Among these secondaries, boron stands out as particularly abundant, making it an ideal tracer for studying CR propagation.

The DArk Matter Particle Explorer (DAMPE), operational since December 2015, features the deepest calorimeter among current space-based CR observatories, enabling direct spectral measurements up to hundreds of TeV.

The cosmic-ray boron spectrum and the B/C and B/O flux ratios are measured from 8.6 GeV/n to 5.5 TeV/n; the carbon and oxygen spectra and the C/O flux ratio results are extended to 4.2 PeV/n.

Speaker: Andrea Serpolla (University of Geneva)

17:18 Synthetic quorum sensing in colloidal active matter

In the living world, organisms often adapt their behavior based on how crowded their environment is—a phenomenon known as quorum sensing. For example, people slow down in crowded spaces, and bacteria change activity depending on population density. However, most synthetic active materials, made of self-propelled particles, lack this ability. They move, but they do not respond to their surroundings, which limits the complexity of patterns they can form. In our study, we introduce a new kind of synthetic material that incorporates quorum sensing to overcome this limitation.

We design microscopic colloidal rods that are powered by an electric field and programmed to sense local density. When the rods are in low-density regions, they actively roll; when they encounter crowded areas, they shut off their inner engine and stop moving. This simple feedback mechanism leads to surprising behaviors. We observe two main effects: one where active and inactive regions coexist, and another where the entire system freezes, entering an absorbing state. By combining experiments, simulations and theoretical modeling, we show how this adaptive behavior emerges from interactions between particles and their environment.

Our findings provide a new design strategy for synthetic materials that can react to their surroundings, a step toward creating active matter that does not just move, but adapts.

Speaker: Alberto Dinelli (Université de Genève)

17:30 → 19:00 Drinks