11/2023 Hydrodynamic efficiency limit on a Marangoni surfer Abdallah Daddi-Moussa-Ider et al.
A Marangoni surfer is an object embedded in a gas-liquid interface, propelled by gradients in surface tension. We derive an analytical theorem for the lower bound on the viscous dissipation by a Marangoni surfer in the limit of small Reynolds and capillary numbers. The minimum dissipation can be expressed with the reciprocal difference between drag coefficients of two passive bodies of the same sh …
10/2023 Intercellular Friction and Motility Drive Orientational Order in Cell Monolayers Michael Chiang et al.
Spatiotemporal patterns in multicellular systems are important to understanding tissue dynamics, for instance, during embryonic development and disease. Here, we use a multiphase field model to study numerically the behavior of a near-confluent monolayer of deformable cells with intercellular friction. Varying friction and cell motility drives a solid-liquid transition, and near the transition bou …
10/2023 Entropy production and thermodynamic inference for stochastic microswimmers Michalis Chatzittofi et al.
The question of characterization of the degree of non-equilibrium activity in active matter systems is studied in the context of a stochastic microswimmer model driven by a chemical cycle. The resulting dynamical properties and entropy production rate unravel a complex interplay between the chemical and the hydrodynamic degrees of freedom beyond linear response, which is not captured by convention …
10/2023 Exploiting memory effects to detect the boundaries of biochemical subnetworks Moshir Harsh et al.
Partial measurements of biochemical reaction networks are ubiquitous and limit our ability to reconstruct the topology of the reaction network and the strength of the interactions amongst both the observed and the unobserved molecular species. Here, we show how we can utilize noisy time series of such partially observed networks to determine which species of the observed part form its boundary, i. …
10/2023 Topological phase locking in dissipatively-coupled noise-activated processes Michalis Chatzittofi et al.
We study a minimal model of two non-identical noise-activated oscillators that interact with each other through a dissipative coupling. We find that the system exhibits a rich variety of dynamical behaviors, including a novel phase-locking phenomenon that we term topological phase locking (TPL). TPL is characterized by the emergence of a band of periodic orbits that form a torus knot in phase spac …
10/2023 Towards a complete mean-field theory for the ductile and brittle yielding of amorphous solids: beyond the paradigm of the Ising model in a random field Jack T. Parley et al.
Developing a unified theory describing both ductile and brittle yielding constitutes a fundamental challenge of non-equilibrium statistical physics. Recently, it has been proposed that the nature of the yielding transition is controlled by physics akin to that of the quasistatically driven Random field Ising model (RFIM), which has served as the paradigm for understanding the effect of quenched di …
10/2023 Collective motion in a sheet of microswimmers Dóra Bárdfalvy et al.
Self-propelled micron-size particles suspended in a fluid, like bacteria or synthetic microswimmers, are strongly non-equilibrium systems where particle motility breaks the microscopic detailed balance, often resulting in large-scale collective motion. Previous theoretical work has identified long-range hydrodynamic interactions as the main driver of collective motion in unbounded dilute suspensio …
09/2023 Scale-dependent heat transport in dissipative media via electromagnetic fluctuations Matthias Krüger et al.
We develop a theory for heat transport via electromagnetic waves inside media, and use it to derive a spatially nonlocal thermal conductivity tensor, in terms of the electromagnetic Green's function and potential, for any given system. While typically negligible for optically dense bulk media, the electromagnetic component of conductivity can be significant for optically dilute media, and sho …
09/2023 Escaping kinetic traps using non-reciprocal interactions Saeed Osat et al.
Kinetic traps are a notorious problem in equilibrium statistical mechanics, where temperature quenches ultimately fail to bring the system to low energy configurations. Using multifarious self-assembly as a model system, we introduce a mechanism to escape kinetic traps by utilizing non-reciprocal interactions between components. Introducing non-equilibrium effects offered by broken action-reaction …
08/2023 The motility-matrix production switch in Bacillus subtilis — a modeling perspective Simon Dannenberg et al.
Phenotype switching can be triggered by external stimuli and by intrinsic stochasticity. Here, we focus on the motility-matrix production switch in Bacillus subtilis. We use modeling to describe the SinR-SlrR bistable switch its regulation by SinI, and to distinguish different sources of stochasticity. Our simulations indicate that intrinsic fluctuations in the synthesis of SinI are insufficient t …