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Ajeya Krishna

Publications and source records attributed to Ajeya Krishna.

2 recordsLinked to original sources

Active Brownian particles can mimic the pattern of the substrate

Active Brownian particles (ABPs) are termed out to be a successful way of modeling the moving microorganism on the substrate. In recent studies, it is shown that such organisms can sense the characteristics of the substrate. Motivated by such work, we studied the dynamics and the steady state of ABP moving on a substrate with space-dependent activity. On the substrate, some regions are marked as high in activity, and other regions are such that particles behave as passive Brownian particles. The system is studied in two dimensions with step, sigmoid, Gaussian and cone shape distribution of activity profile on the substrate. The whole interface of the activity profile is symmetrically divided into two regions. This lead to the flow of particles from the active region to the passive region. The final steady state of particle density profile, polarisation and flux very much follows the structure of the inhomogeneous activity and the density in high activity region is lower, maximum at the interface and nearly constant with mean density in the passive region. Further, the steady state density profile for various shapes and designs on two-dimensional substrates. Hence the collection of ABPs on an inhomogeneous substrate can mimic the inhomogeneity of the substrate.

cond-mat.soft

Inhomogeneous activity enhances density phase separation in active model B

We study the binary phase separation in active model B, on a two-dimensional substrate with inhomogeneous activity. The activity was introduced with a maximum value at the center of the box and spread as a Bivariate-Gaussian distribution as we move away from the center. The system was studied for three different intensities of the distribution. Towards the boundary of the box, activity is zero or the model is similar to the passive model B. We start from the random homogeneous distribution of density of particles, and the system evolves towards a structured distribution of density. With time, density starts to phase separately with maximum density at the center of the box and decreases as we move away from the center of the box. The width of the density profile at the center increases as a power lawexponentα(t) remains close between 2/3 to 3/4 up to some moderate time and then decays to zero in the steady state. Hence, our result shows the response of density in an active binary system with respect to the patterned substrate. It can be used to design devices useful for the trapping and segregation of active particles.

cond-mat.soft