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A key question for machine learning approaches in particle physics is how to best represent and learn from collider events. As an event is intrinsically a variable-length unordered set of particles, we build upon recent machine learning…

High Energy Physics - Phenomenology · Physics 2020-04-17 Patrick T. Komiske , Eric M. Metodiev , Jesse Thaler

We analyze the ponderomotive action experienced by a small spherical particle immersed in an optical field, in relation to the internal energy flows (optical currents) and their spin and orbital constituents. The problem is studied…

Optics · Physics 2023-11-02 Aleksandr Bekshaev

We introduce a simple model of active transport for an ensemble of particles driven by an external shear flow. Active refers to the fact that the flow of the particles is modified by the distribution of particles itself. The model consists…

Exactly Solvable and Integrable Systems · Physics 2009-11-10 Cristobal Lopez

Active inference is a theory that underpins the way biological agent's perceive and act in the real world. At its core, active inference is based on the principle that the brain is an approximate Bayesian inference engine, building an…

Artificial Intelligence · Computer Science 2020-03-09 Ozan Çatal , Samuel Wauthier , Tim Verbelen , Cedric De Boom , Bart Dhoedt

The hydrodynamic flow field around a catalytically active colloid is probed using particle tracking velocimetry both in the freely swimming state and when kept stationary with an external force. Our measurements provide information about…

Soft Condensed Matter · Physics 2019-09-11 Andrew I. Campbell , Stephen J. Ebbens , Pierre Illien , Ramin Golestanian

Fluid flow around a random distribution of stationary spherical particles is a problem of substantial importance in the study of dispersed multiphase flows. In this paper we present a machine learning methodology using Generative…

Fluid Dynamics · Physics 2021-11-02 B. Siddani , S. Balachandar , W. C. Moore , Y. Yang , R. Fang

Active semiflexible filaments are crucial in various biophysical processes, yet insights into their single-filament behavior have predominantly relied on theory and simulations, owing to the scarcity of controllable synthetic systems. Here,…

Soft Condensed Matter · Physics 2025-07-14 Bipul Biswas , Prasanna More , Hima Nagamanasa Kandula

We consider a rigid assembly of two active Brownian particles, forming an active colloidal dimer, in a gradient of activity. We show analytically that depending on the relative orientation of the two particles the active dimer accumulates…

Soft Condensed Matter · Physics 2022-08-17 Hidde D. Vuijk , Sophie Klempahn , Holger Merlitz , Jens-Uwe Sommer , Abhinav Sharma

This review treats asymmetric colloidal particles moving through their host fluid under the action of some form of propulsion. The propulsion can come from an external body force or from external shear flow. It may also come from…

Fluid Dynamics · Physics 2020-09-14 Thomas A. Witten , Haim Diamant

Despite the plethora of deep learning frameworks for flow field prediction, most of them deal with flow fields on regular domains, and although the best ones can cope with irregular domains, they mostly rely on graph networks, so that real…

Machine Learning · Computer Science 2024-08-14 Laurent de Vito , Nils Pinnau , Simone Dey

We performed a numerical study to train smart inertial particles to target specific flow regions with high vorticity through the use of reinforcement learning algorithms. The particles are able to actively change their size to modify their…

Fluid Dynamics · Physics 2018-09-19 Simona Colabrese , Kristian Gustavsson , Antonio Celani , Luca Biferale

We consider sedimented at a solid wall particles that are immersed in water containing small additives of photosensitive ionic surfactants. It is shown that illumination with an appropriate wavelength, a beam intensity profile, shape and…

A longstanding open question in the field of dense disordered matter is how precisely structure and dynamics are related to each other. With the advent of machine learning, it has become possible to agnostically predict the dynamic…

We review recent experimental, numerical, and analytical results on active suspensions of self-propelled colloidal beads moving in (quasi) two dimensions. Active colloids form part of the larger theme of active matter, which is noted for…

Soft Condensed Matter · Physics 2014-09-03 Julian Bialké , Thomas Speck , Hartmut Löwen

A simple model of an active colloid consisting of dumbbell-shaped particles that cyclically change their length without propelling themselves is proposed and analyzed. At nanoscales, it represents an idealization for bacterial cytoplasm or…

Adaptation and Self-Organizing Systems · Physics 2020-01-28 Yuki Koyano , Hiroyuki Kitahata , Alexander S. Mikhailov

We train a deep convolutional neural network to predict hydrodynamic results for flow coefficients, average transverse momenta and charged particle multiplicities in ultrarelativistic heavy-ion collisions from the initial energy density…

High Energy Physics - Phenomenology · Physics 2023-03-09 H. Hirvonen , K. J. Eskola , H. Niemi

Light-activated self-propelled colloids are synthesized and their active motion is studied using optical microscopy. We propose a versatile route using different photoactive materials, and demonstrate a multiwavelength activation and…

Soft Condensed Matter · Physics 2014-10-28 J. Palacci , S. Sacanna , S. -H. Kim , G. -R. Yi , D. J. Pine , P. M. Chaikin

We show how a gradient in the motility properties of non-interacting point-like active particles can cause a pressure gradient that pushes a large inert object. We calculate the force on an object inside a system of active particles with…

Statistical Mechanics · Physics 2017-10-03 Nitzan Razin , Raphael Voituriez , Jens Elgeti , Nir S. Gov

We investigate the effect of cooperative interactions in an ensemble of microorganisms, modelled as self-propelled disk-like and rod-like particles, in a three-dimensional turbulent flow to show flocking as an emergent phenomenon. Building…

Soft Condensed Matter · Physics 2020-05-20 Anupam Gupta , Amal Roy , Arnab Saha , Samriddhi Sankar Ray

Colloidal probes immersed in an active bath have been found to behave like active particles themselves. Here, we use coarse-grained simulations to investigate the mechanisms behind this behavior. We find that the active motion of the…

Soft Condensed Matter · Physics 2024-01-18 Jeanine Shea , Gerhard Jung , Friederike Schmid