By Prof. Manas Khan, Indian Institute of Technology Kanpur

Abstract:

Active Brownian dynamics are inherently asymmetric because of the persistence in motion up to a characteristic timescale, the persistent time (τ_R), governed by the rotational diffusion. Thus, active Brownian particles undergo exotic dynamical variations when they interact with complex environment possessing inherent asymmetry, and timescale such as relaxation time. Many of these dynamical behaviors and their governing parameters remain to be properly investigated and understood. Since naturally occurring micro swimmers and the application-oriented-synthesized-self-propelled particles often need to pass through complex fluids and confinements, it is of paramount importance to understand how their dynamics adapt to these environments.

In this talk, I will discuss our recent studies on the dynamics of self-propelled active Brownian particles confined to a harmonic potential, thus introducing them to a radially symmetric restoring force field with a characteristic equilibration time τ. In experiments, we have investigated dynamical behaviors of self-thermophoretic, as well as self-diffusiophoretic active motions of half-platinum-coated Janus colloids in an optical trap. We have also performed Brownian dynamics simulations and analytical calculations to have a better understanding of this system. Emphasizing on the technical details of our experiments, I will discuss a novel dynamical transition that the system undergoes. A competition between the characteristic length scale of the active Brownian motion and the harmonic well fully governs this transition. Time permitting, I will show that we can even characterize this as a weak to strong ergodicity breaking transition.

IISER-PHY PUNE is inviting you to a scheduled Zoom meeting.

Topic: Physics Seminar - Prof. Manas Khan

Time: Mar 16, 2023 04:00 PM India

Join Zoom Meeting

https://zoom.us/j/93751245175?pwd=bmpIYXVzYlpCdldYQmN2bVhIMFJWdz09

Meeting ID: 937 5124 5175

Passcode: 425054

Host: Optica Student Chapter-IISER Pune Optics League