arXiv subjects

Priyanka Iyer

Publications and source records attributed to Priyanka Iyer.

6 recordsLinked to original sources

arXiv2026

Emergent Self-Organisation of Intelligent Active Particles

Intelligent active particles are characterized by self-propulsion, directional sensing of their environment, information processing, decision making and goal-oriented self-steering. This implies, in particular, the prevalence of non-reciprocal interactions, and the importance of information propagation through agent groups. Examples include biological systems (cells, insects, birds, fish, pedestrians) as well as engineered systems (nano- and microbots). As many agents move in an aqueous medium, hydrodynamic interactions strongly affect the dynamics. The emergent dynamics includes the formation of swarms and flocks, predator-prey behavior, and the navigation in complex environments.

physics.bio-ph↗

arXiv2024

Interacting Streams of Cognitive Active Agents in a Three-Way Intersection

The emergent collective motion of active agents - in particular pedestrians - at a three-way intersection is studied by Langevin simulations of cognitive intelligent active Brownian particles (iABPs) with directed visual perception and self-steering avoidance. Depending on the maneuverability $\Omega$, the goal fixation $K$, and the vision angle $\psi$, different types of pedestrian motion emerge. At intermediate relative maneuverability $\Delta = \Omega/K$ and large $\psi$, pedestrians have noisy trajectories due to multiple scattering events as they encounter other pedestrians in their field of view. For $\psi = \pi$ and large relative maneuverability $\Delta$, an effectively jammed state is found, which belongs to the percolation universality class. For small $\psi$, agents exhibit localised clustering and flocking, while for intermediate $\psi$ self-organized rotational flows can emerge. The analysis of mean squared displacement and velocity auto-correlation of the agents reveals that the motion is well described by fractional Brownian Motion with positively correlated noise. Finally, despite the rich variety of collective behaviour, the fundamental flow diagram for the three-way-crossing setup shows a universal curve for the different vision angles. Our research provides valuable insights into the importance of vision angle and self-steering avoidance on pedestrian dynamics in semi-dense crowds.

cond-mat.stat-mech↗

arXiv2024

Controlling Inter-Particle Distances in Crowds of Motile, Cognitive, Active Particles

Distance control in many-particle systems is a fundamental problem in nature. This becomes particularly relevant in systems of active agents, which can sense their environment and react by adjusting their direction of motion. We employ agent-based simulations to investigate the complex interplay between agent activity, characterized by P{é}clet number $Pe$, reorientation maneuverability $Ω$, vision angle $θ$ and vision range $R_0$, and agent density, which determines agent distancing and dynamics. We focus on semi-dense crowds, where the vision range is much larger than the particle size. The minimal distance to the nearest neighbors, exposure time, and persistence of orientation direction are analyzed to characterize the behavior. With increasing particle speed at fixed maneuverability, particles approach each other more closely, and exhibit shorter exposure times. The temporal persistence of motion decreases with increasing $Pe$, reflecting the impact of activity and maneuverability on direction changes. For a vision angle $θ=π/4$, we observe the emergence of flocking aggregates with a band-like structure, reminiscent of the Viscek model. Additionally, for vision angles $θ\ge π/2$, several quantities are found to display a universal scaling behavior with scaling variable $Pe^{3/2}/Ω$. Our results are in good agreement with recent experiments of pedestrians in confined spaces.

physics.bio-ph↗

arXiv2023

Dynamic shapes of floppy vesicles enclosing active Brownian particles with membrane adhesion

Recent advances in micro- and nano-technologies allow the construction of complex active systems from biological and synthetic materials. An interesting example is active vesicles, which consist of a membrane enclosing self-propelled particles, and exhibit several features resembling biological cells. We investigate numerically the behavior of active vesicles, where the enclosed self-propelled particles can adhere to the membrane. A vesicle is represented by a dynamically triangulated membrane, while the adhesive active particles are modelled as active Brownian particles (ABPs) that interact with the membrane via the Lennard-Jones potential. Phase diagrams of dynamic vesicle shapes as a function of ABP activity and particle volume fraction inside the vesicle are constructed for different strengths of adhesive interactions. At low ABP activity, adhesive interactions dominate over the propulsion forces, such that the vesicle attains near static configurations, with protrusions of membrane-wrapped ABPs having ring-like and sheet-like structures. At moderate particle densities and strong enough activities, active vesicles show dynamic highly-branched tethers filled with string-like arrangements of ABPs, which do not occur in the absence of particle adhesion to the membrane. At large volume fractions of ABPs, vesicles fluctuate for moderate particle activities, and elongate and finally split into two vesicles for large ABP propulsion strengths. We also analyze membrane tension, active fluctuations, and ABP characteristics (e.g., mobility, clustering), and compare them to the case of active vesicles with non-adhesive ABPs. The adhesion of ABPs to the membrane significantly alters the behavior of active vesicles, and provides an additional parameter for controlling their behavior.

cond-mat.soft↗

arXiv2022

Phase separation of active Brownian particles on curved surfaces

The effect of curvature on an ensemble of repulsive active Brownian particles (ABPs) moving on a spherical surface is studied. Surface curvature strongly affects the dynamics of ABPs, as it introduces a new time scale $τ=R/v_0$, with curvature radius $R$ and propulsion velocity $v_0$, in addition to the rotational diffusion time $τ_r$. This implies that motility-induced phase separation (MIPS) disappears for small $R$. Furthermore, it causes a narrowing of the MIPS regime in the phase diagram of P{é}clet number $\text{Pe}$ and particle area fraction $ϕ$. Also, the phase-separation boundary at low $ϕ$ attains a turning point at small $R$, allowing for the possibility of a reentrant behavior. These results characterize the effect of curvature on ABP dynamics and MIPS, and will help to better understand the preferred occupation of certain niches by bacterial colonies in porous media.

cond-mat.soft↗

arXiv2020

Automated Detection of Accelerating Solar Eruptions using Parabolic Hough Transform

Solar eruptions such as Coronal Mass Ejections (CMEs) observed in the inner solar corona (up to 4 R$_{\odot}$) show acceleration profiles which appear as parabolic ridges in height-time plots. Inspired by the white-light automated detection algorithms, Computer Aided CME Tracking System (CACTus) and Solar Eruptive Events Detection System (SEEDS), we employ the parabolic Hough Transform for the first time to automatically detect off-disk solar eruptions {from height-time plots. Due to the limited availability of white-light observations in the inner corona, we use Extreme UltraViolet (EUV) images of the Sun. In this paper we present a new algorithm, CME Identification in Inner Solar Corona (CIISCO), which is based on Fourier motion filtering and the parabolic Hough transform, and demonstrate its implementation using EUV observations taken from {\it Atmospheric Imaging Assembly} (AIA) on-board the Solar Dynamics Observatory (SDO), {\it Extreme Ultra Violet Imager} (EUVI) on-board the STEREO-A and B satellites, and {\it Sun Watcher using Active Pixel System detector and Image Processing} (SWAP) Imager on-board PROBA2. We show that CIISCO is able to identify any {off-disk} outward moving feature in EUV images. The use of automated detection algorithms, like CIISCO, can potentially be used to provide early warnings of CMEs if an EUV telescope is located at $\pm$ 90$^{\circ}$ from the Sun-Earth line, providing CME characteristics and kinematics close to the Sun. This paper also presents the limitations of this algorithm and the prospects for future improvement.

astro-ph.SR↗