Research

In my Ph.D. thesis, I experimentally showed the Mpemba effect in a colloidal system with a micron-sized silica bead diffusing in a bath. When a system is quenched from an initially hot equilibrium state to a cold equilibrium state, the evolution of the system between the initial and the final state is a strongly nonequilibrium process. As a nonequilibrium state cannot, in general, be characterized by a single temperature, we adopted the notion of a “distance” measure as a proxy for temperature. We showed Mpemba effects in an asymmetric double-well potential. Our experimental results agreed quantitatively with predictions based on the Fokker-Planck equation.

Using understanding gained from the Mpemba effect, I designed an experiment to investigate the opposite effect and present the first experimental evidence for this inverse Mpemba effect. Contrary to the cooling effect, the inverse effect is related to a phenomenon where a system that is initially cold heats up faster than an initially warm system. By understanding the underlying mechanism of these anomalous effects, we demonstrate strong Mpemba and inverse Mpemba effects, where a system can cool or heat exponentially faster to the bath temperature than under typical conditions.

I started experiments on photophoretic forces in Dr. Ayan Banerjee's lab at IISER Kolkata as a part of my Master's thesis. I trapped absorbing micro-particles in air by photophoretic forces generated using a single loosely focused Gaussian trapping beam. I showed that the trapped particle underwent spontaneous rotation due to the action of this force. Using the signature of the rotation from the power spectral densities of the trapped particles, I measured their masses through resonance and rotational frequencies.

In my leisure time, which I often don't get, I spend time building robotic stuff. I like making electronic toys and coding them to install a sense of life.