Talks

How might quantum platforms reshape many body physics?

Quantum platforms are nearing a scale where they will allow the realization of a vast number of quantum circuits. Some of these will solve computational problems of interest to industry and commerce, others will answer questions about quantum systems that we normally ask. But this will still leave much room for searching for entirely new quantum phenomena. In this talk I will describe some thinking on one concrete possibility - that of exploring quantum games - and on a general method for using these platforms in "discovery mode" much like the use of particle accelerators for discovering new particle physics

AI, Genetic Engineering and the Post-Human Future

Around the turn of the millennium, I became convinced that a post-human age was probably in view, and that it would likely arrive in my own lifetime. Around 2012, with the arrival of AlexNet and the demonstration of CRISPR as a programmable gene-editing tool, this conviction was significantly strengthened. The period since has seen technological advances that have narrowed the error bars on the expected time-scale for this transformation. I will describe how I think about the present moment in this framework with the help of some metaphors from physics. I will also sketch what could, in theory, be done to make the transition less disruptive.

From Many Models, One: Forecasting with Reservoir Ensembles

Model combination is a powerful approach for achieving superior performance compared to selecting a single model. We study both analytically and empirically the effectiveness of ensembles. For Hedge and Follow-the-Leader schemes, we derive general theoretical online combination guarantees by extending known bounds to the dependent data setting. We then apply ensemble learning methods to Multi-Frequency Echo State Networks (MFESNs): the proposed Ensemble Echo State Networks demonstrate significantly improved predictive performance relative to individual MFESN models. (Presentation based on the working paper: https://arxiv.org/abs/2512.13642)

The hidden structure of chaotic many-body quantum systems

Quantum statistical mechanics dictates that interacting many-body systems chaotically thermalize and forget their past. While this narrative accurately describes simple observables, it can break when we examine the full complexity of the wavefunction amplitudes, a feat now made possible by the unprecedented control of modern quantum computers and simulators. In this talk, I will show that even within the regime of many-body chaos, quantum states can harbour a persistent, hidden structure. By analysing a broad class of interacting spin models, I will demonstrate that highly entangled, thermal eigenstates often maintain an anomalously large overlap with specific product states - remembrances of unstable classical trajectories that survive in the Hilbert space. This structure causes the system to deviate from universal statistical predictions and resist the complete loss of information, providing a new perspective on many-body quantum chaos and highlighting the fundamental limits of thermalization.

Quantum Dynamics Seminar: tba

Programming Shape in Living Tissues

Living tissues are active materials that continuously generate, transmit, and dissipate mechanical stresses across scales. Yet how these stresses give rise to robust three-dimensional shapes remains incompletely understood. In this talk, I will present recent work exploring two complementary physical mechanisms by which cellular monolayers undergo shape transformations: active viscoelastic buckling and nematic-guided morphogenesis. In the first part, I will delineate the mechanical rules governing epithelial buckling by combining an experimental system that allows us to sculpt epithelial shells and subject them to controlled deflation with a 3D computational model linking cytoskeletal dynamics to tissue mechanics. We show that epithelial buckling emerges from the interplay between the applied loading rate, the viscoelasticity of the actin cortex, and active contractility. We find that epithelial buckling is a multiscale phenomenon involving long-lived supracellular folds as well as short-lived subcellular wrinkles in the actin cortex. By forming epithelial shells with anisotropic curvature, we explore symmetry breaking and direct buckling into predictable wrinkle patterns. In the second part, I will present a strategy to program tissue shape transformations through the nematic organization of cellular forces. By controlling nematic order and topological defects, we generate tissues programmed with specific stress fields. Using a theoretical framework coupling contractile nematics with thin-sheet mechanics, we show that nematically guided active stresses can drive morphogenesis through Gaussian morphing. Experimentally, detachment of nematic tissues triggers out-of-plane deformations, generating reproducible three-dimensional shapes. Together, these studies establish a unifying physical framework in which tissue shape emerges from active stresses, viscoelasticity, nematicity, and geometric frustration. Beyond advancing our understanding of morphogenesis, this framework enables the design of synthetic shape-programmable living surfaces.

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Life at High Reynolds Number

Unlike coffee and cream that homogenize when stirred, growing micro-organisms (e.g., bacteria and unicellular marine organisms) can actively kill each other and avoid mixing. How do such antagonistic interactions impact the growth and survival of competing strains, while being spatially advected by turbulent flows? By using analytic arguments and numerical simulations of a continuum model, we describe the dynamics of two antagonistic strains that are dispersed by both compressible and incompressible turbulent flows in two spatial dimensions. A key parameter is the ratio of the fluid transport time to that of biological reproduction, which determines the winning organism that ultimately takes over the whole population from an initial heterogeneous state, a process known as fixation. By quantifying the probability and mean time for fixation, we discuss how turbulence raises the threshold for biological nucleation and antagonism suppresses flow-induced mixing by depleting the population at interfaces. We highlight the unusual biological consequences of the interplay of turbulent fluid flows with antagonistic population dynamics, with potential implications for marine microbial ecology and origins of biological chirality.

ATOM26 Colloquium