Research

I am working as an assistant professor at the Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Punjab, India from February 2022 to date. My research interests are in the fields of Soft Condensed Matter Physics and Statistical Mechanics, especially in the kinetics of phase separation, granular material, amorphous solids, active matter systems, and thermal glasses. Following are some of the current research topics:

A. Sponsored Projects

1. IISER Mohali Seed Grant:

Project Title: Phase Separation Kinetics in Multi-component Active Matter Systems

Project Duration: 01-April-2022 to 31-March-2025

Amount: 20 Lakh Rupees

2. SERB Start-up Research Grant (Grant No: SRG/2022/000105)

Project Title: Rheology of Dense Granular Systems

Project Duration: 01-October-2022 to 30-September-2024

Amount: 25 Lakh Rupees (Approx.)

B. Brief Summary of Research

1. Kinetics of Phase Separation: I have studied domain growth kinetics in ferroelectric thin films, ordering kinetics in critical and off-critical binary alloys, surface-directed spinodal decomposition on morphologically and chemically patterned substrates, and domain growth in binary fluid mixtures. Currently, I am working on phase separation in active matter systems.

2. Dynamical Properties of Granular Systems: I have studied the granular system cools by solid friction and frictional granular matter. In the latter case, the friction force is proportional to the direction of the relative velocity. I have studied the Brownian motion of a particle under the solid friction, and clustering and velocity distributions of a granular system cooling by solid friction. Also, I studied a heated granular system where the system's energy loss is due to the solid friction and dynamics of an intruder in a heated granular fluid. In frictional granular matter, I have numerically studied the shear-induced inhomogeneous dilation of compressed granular systems and presented a scaling theory to explain our numerical results. Also, I found universal scaling laws for shear-induced dilation in frictional granular media under cyclic compression-decompression.

3. Plastic Instabilities and Density of Low-frequency States in Amorphous Solids: I have studied the plastic instabilities in the charged granular matter under the influence of external loading and electric field, plastic instability and yielding transition in amorphous solids under pure shear deformation, and instabilities in thermal glasses below the glass transition temperature T_g. I have explored the density of low-frequency quasi-localized modes in charged amorphous granular systems and thermal glasses below the glass transition temperature T_g.

4. Anomalous Elasticity in Amorphous Systems: Amorphous solids appear to react elastically to small external strains, but in contrast to ideal elastic media, plastic responses abound immediately, at any value of the strain. The existence of such plastic responses results in screened elasticity in which stresses and strains are quantitatively or qualitatively different from the unscreened theory, depending on the specific screening mechanism. We want to develop a theory of such screening effects by plastic quadrupoles, dipoles, and monopoles, using analogy from electrostatics and want to understand the anomalous response of amorphous materials under various driving and boundary conditions.

C. Advanced Computational Techniques

1. Force-driven molecular dynamics simulation - used to study the phase separation kinetics in the bulk of a binary fluid mixture, thermal and mechanical properties of frictional or friction-less dilute and dense granular matter.

2. Event-driven molecular dynamics simulation - applied on hard-sphere systems, where particles interact with each other only when they collide, and positions and velocities of the particles are updated by the binary collision time between two particles.

3. Relaxation Algorithms - used conjugate gradient method and FIRE algorithm to study the plastic instabilities, density of states of amorphous systems at zero temperature and charged granular matter under the external deformation and electric field.

4. Regular and Accelerated Monte-Carlo simulation - applied on Glauber spin-flip model and Kawasaki spin-exchange kinetics to access late-stage kinetics of phase odering and phase separation in binary alloys. Also, used this technique to study density of states and plastic instabilities in thermal glasses under simple shear deformation.

5. Swap Monte-Carlo Algorithm - used in the simulation of thermal glasses. It speeds-up the simulation of glass forming liquids and enables us to study the structure of glasses under conditions that were so far not accessible, even in experiments.

6. Ewald summation technique - used in the simulation of charged granular matter to tackle the effect of long-ranged electrostatic interaction.

7. Langevin simulation - applied on coarse-grained models of ferromagenets, binary alloys, ferroelectric films, surface-directed spinodal decomposition, and Model H simulation of binary fluid mixtures etc.

8. Lattice-Boltzmann simulation - applied on phase separation in binary fluid mixtures using Model H kinetics. In this context, my knowledge is at the basic level. I want to use this technique in active matter and granular systems.