arXiv subjects

Anweshika Pattanayak

Publications and source records attributed to Anweshika Pattanayak.

5 recordsLinked to original sources

arXiv2026

Characterizing exact dynamics of a trapped active Brownian particle under torque in two and three dimensions

The interplay of chirality, self-propulsion, and spatial confinement generates striking non-equilibrium fluctuations whose higher-order statistics carry information about the dynamics and shape of the position distribution. Here, we present an exact analytical framework, based on a Laplace-transform solution of the Fokker-Planck equation, for the transient dynamics of a chiral active Brownian particle in a harmonic trap, in both two and three dimensions. We obtain closed-form expressions for all time-dependent moments up to fourth order, enabling a complete characterization of the excess kurtosis throughout the transient and steady-state regimes. In two dimensions, the excess kurtosis exhibits a damped oscillatory response with multiple re-entrant crossovers, evolving from negative values that reflect active off-centered ring-like position distributions to positive values characteristic of heavy-tailed fluctuations. This damped oscillatory excess kurtosis appears both for free and harmonic confinement, although increasing the trapping stiffness progressively suppresses it, and the positive excess kurtosis eventually vanishes at sufficiently high stiffness. In contrast, in three dimensions, the excess kurtosis remains negative, indicating a robustly active non-Gaussian state characterized by half-ring-like to band-like position distributions in the two-dimensional plane spanned by the torque axis and its normal radial direction. Our results demonstrate how chirality, propulsion, and confinement, together with dimensionality, shape transient dynamics, while providing experimentally accessible signatures of confined chiral active dynamics.

cond-mat.soft↗

arXiv2025

Chirality, confinement and dimensionality govern re-entrant transitions in active matter

The non-equilibrium dynamics of individual chiral active particles underpin the complex behavior of chiral active matter. Here we present an exact analytical framework, supported by simulations, to characterize the steady states of two-dimensional chiral active Brownian particles and three-dimensional torque-driven counterparts in a harmonic trap. Using a Laplace-transform approach of the Fokker-Planck equation, we derive closed-form expressions for displacement moments and excess kurtosis, providing a precise probe of non-Gaussian statistics. Our analysis reveals three distinct regimes: bimodal active states with off-center peaks, Gaussian-like passive states, and weakly heavy-tailed distributions unique to two dimensions. We show that dimensionality plays a decisive role: in two dimensions, increasing chirality suppresses activity and restores passive behavior, while in three dimensions torque preserves activity along the torque axis, producing anisotropic steady states. These behaviors are captured by simple active length-scale arguments that map the boundaries between passive and active phases. Our results offer concrete experimental signatures - including kurtosis crossovers, off-center peaks, and torque-induced anisotropy - that establish confinement as a powerful tool to probe and control chiral and torque-driven active matter.

cond-mat.soft↗

arXiv2025

Inertia-chirality interplay in active Brownian motion: exact dynamics and phase maps

We present an exact, time-resolved theory for a two-dimensional chiral active Brownian particle (cABP) with translational inertia. Using a Laplace-transform moment hierarchy, we derive closed-form expressions for the mean velocity, velocity-orientation projections, velocity autocorrelation, mean-squared velocity, mean-squared displacement, and the fourth moment of velocity. These results agree quantitatively with simulations over all masses, activities, and chiralities. We show that the velocity autocorrelation factorizes into an inertial envelope and a chiral envelope. Despite rich transients in the velocity sector, the long-time positional diffusion equals the overdamped cABP value, independent of mass. From the steady mean-squared velocity, we define a kinetic temperature and a modified fluctuation-dissipation relation whose violation vanishes in two limits: large mass or large chirality, identifying chirality as an additional route to equilibrium-like behavior. The steady-state velocity excess kurtosis gives a phase map that exhibits a (Gaussian-like)-active(bimodal)-(Gaussian-like) re-entrance with mass; chirality confines activity and shrinks the active sector. A narrow positive-kurtosis window emerges at large mass and intermediate chirality, with analytic boundaries consistent with the heavy-mass asymptote.

cond-mat.stat-mech↗

arXiv2024

Impact of chirality on active Brownian particle: Exact moments in two and three dimensions

In this work, we investigate the effects of chirality, accounting for translational diffusion, on active Brownian particles in two and three dimensions. Despite the inherent complexity in solving the Fokker-Planck equation, we demonstrate a Laplace transform method for precisely calculating the temporal evolution of various dynamic moments. Our analysis yields explicit expressions for multiple moments, such as the second and fourth moments of displacement, revealing the impact of persistence and chirality. These moments exhibit oscillatory behaviour, and excess kurtosis indicates deviations from the Gaussian distribution during intermediate time intervals.

cond-mat.stat-mech↗

arXiv2023

Hydrodynamics of passive and active rods in a temperature gradient

Temperature plays a very important role in various biological processes like the evolution of life, as it is anticipated that early life existed in a very hot environment that eventually cooled down with time. In vitro experiments, conducted with various active matter systems in anisotropic temperature environments, show several interesting outcomes. Motivated by these experiments and some simulation results, we study the collective behavior of self-propelled hard rods with excluded volume interactions, moving on a substrate in two dimensions and subjected to a small but finite external temperature gradient. Using a coarse-grained hydrodynamic approach, we explore the behavior of the system in the steady state and the stability both in the passive and active limits.

cond-mat.soft↗