Neural systems form networks embedded in physical space. Local self-regulation, spanning fast synaptic dynamics to slower homeostatic plasticity, refines this scaffold into collective dynamics that are both stable and flexible. This stability, however, is not guaranteed, as recurrent excitation can push such networks toward runaway activity, reminiscent of epileptic seizures. Yet, biological networks reliably settle into stable regimes between silence and saturation, and they can shift their working regime on demand. It remains unclear whether those stable yet flexible dynamics arise from the same mechanisms, and how much of the network's dynamical repertoire is fixed by its topology alone. In this talk, I combine statistical physics of nonequilibrium phase transitions with spiking models, experimental data, and neuromorphic hardware. Together, these approaches show that topology and local self-regulation jointly define a shared repertoire of collective states - from stationary activity to traveling waves and synchronized bursts - and that external stimulation can steer a network between them. Our results provide insight into how topology and local self-regulation shape the stability-flexibility trade-off in biological neural networks. Extending this framework toward associative learning mechanisms could guide new generations of scalable, bio-inspired AI systems.
Understanding the behavior of interacting quantum many-body systems remains one of the central challenges in modern physics. Even relatively simple models quickly become intractable on classical computers, limiting our ability to access exotic quantum phases and dynamics. Quantum simulation offers an alternative approach: instead of solving the problem numerically, we build a controlled quantum system in the laboratory that directly realizes the model of interest. In this talk, I will introduce quantum gas microscopes - neutral atoms trapped in optical lattices with single-atom resolution and control. Our experimental platform extends these capabilities to large homogenous systems with >3,000 sites. As an example, I will present recent results on dynamically generating U(1) quantum spin liquids, and on realizing the corresponding lattice gauge theory, opening a path toward (2+1)d quantum electrodynamics with ultracold atoms. Together, these developments let us engineer and probe quantum matter in entirely new ways, at the interface of condensed matter and quantum information.
What do dancing couples and atomically-thin crystals have in common? In both cases, the outcome depends on the participants and the rules constraining their motion and interactions. In crystals, symmetry sets these rules, determining how electrons move, respond to light, and how photoexcited bound electron-hole pairs – excitons – interact.
Van der Waals materials are a playground for these effects, combining low dimensionality, diverse crystal symmetries, and optical selection rules. In this talk, I will discuss introduce the field, and show how light polarisation can control many-body excitonic interactions, and how heterostructures can tune exciton wavefunctions.
Using photocurrent spectroscopy in monolayer WSe2 [1], I will show how exciton–exciton interactions resemble dancing pairs on a crowded floor: as exciton density increases, collisions and scattering become more frequent, with the interaction strength controlled by light polarisation. I will also show how low-symmetry materials can imprint their symmetry onto excitons in two-dimensional semiconductors [2], producing linearly polarised photoluminescence even when the materials are separated by several nanometers.
Together, these studies illustrate how van der Waals materials enable control of light–matter interactions, photocarrier dynamics, and many-body effects, providing routes towards on-chip polarisation-sensitive photodetectors and optical control of more exotic phases, such as excitonic condensates.
References:
1. D. Vaquero, et al., Nano Letters 26, 6641 (2026).
The top quark, the heaviest known elementary particle, has long been thought unable to form bound states. However, intriguing hints in recent LHC data suggest that toponium, a short-lived quasi-bound state of a top-antitop pair, might have left observable traces in data and perhaps even been observed for the first time. In this talk, I will discuss why toponium provides a unique laboratory for studying the strong interaction in the non-relativistic regime, how modern techniques allow us to incorporate bound-state effects into state-of-the-art collider simulations, and which experimental signatures could reveal the presence of toponium in present and future LHC data. Finally, I will highlight recent results, ongoing searches and the exciting prospects for using toponium as a new window into top-quark physics.
A dissipative structure, in the sense introduced by Ilya Prigogine (Nobel Prize in Chemistry, 1977), is an ordered pattern that exists only through continuous dissipation: it vanishes the moment the driving stops. Nearly fifty years later, we revisit the origin of this concept and trace how our view of dissipation has shifted, from wasted heat to an active agent of selection and control, as seen for instance in kinetic proofreading.
Two themes will guide the talk. First, for given dissipation channels, the amplitude of the driving can stabilize configurations that would be unstable in equilibrium (like Rayleigh–Bénard cells). Second, the reverse also occurs: dissipation can destabilize. This is the thermodynamic counterpart of Ziegler's paradox (1952), in which a driven system that is perfectly stable becomes unstable when an arbitrarily small amount of damping of a certain type is added, giving rise to new phenomena (as in the tippe top).
Today, steady-state nonequilibrium statistical mechanics is enjoying a renaissance. Experiments now visualize individual trajectories, and they are catching up with theoretical ideas of dynamical ensembles. This opens new ways to ask what, beyond entropy production, shapes the order we see around us.
Individual molecules are fascinating objects of study – not only regarding their localization via microscopy but also as bright single-photon sources. Under liquid-helium conditions, they exhibit highly coherent optical properties, including lifetime-limited linewidths and the emission of coherent photons. The phenomenon of photon antibunching displays coherent characteristics that allow this coherent spectroscopy to be compared with magnetic resonance.
I will demonstrate the coherent properties of such a single emitter and explain the underlying principles.
Magnetometry using nitrogen-vacancy (NV) centers represents a logical extension. Their coherent coupling enables more precise – or perhaps even exact? – localization of the emitters. The coherent properties of a single emitter are compared with those of a large atomic ensemble, highlighting both similarities and differences. Furthermore, practical applications of such optically pumped magnetometers are discussed. Finally, the fundamental operating principle and the technical implementation of such a quantum sensor are explained.
Several mega-trends of our age promise to shift the boundary of what we can measure and image. The building blocks of the quantum computer - single atoms, single molecules, single spins - can also be used as novel sensors. At the same time, modern signal processing and artificial intelligence can increasingly make sense of even weak and noisy signals like single photons.
I will present recent work of our laboratory, which aims to harness these developments for sensing and imaging at the nanoscale.
My talk will in particular cover "low level flight at the nanoscale", a novel approach towards scanning probe microscopy, which can employ extended millimeter-sized planar sensors like bulk diamonds or electric circuits as scanning probes, while still approaching them into 10 nm proximity of samples. I will discuss how this technique can deliver insight into samples like lithium batteries when paired with diamond quantum sensors, and how it could give rise to optical near-field microscopes with atomic resolution based on scanning plasmonic nanogap cavities.
I will also present work towards novel microscopy methods for label-free imaging of nanoscale motion and action potentials in cells, based on recent cameras that operate at the quantum limit while processing milliwatt-level optical power.
