Research

My research interests include:

Non-equilibrium dynamics in active systems

Emergent collective phenomena and rheology in active matter

Modeling advance adaptive active & living systems

Intelligent active matter (IAM)

Overview of past and ongoing research:

Emergent rheology in active matter

Rheology in active matter is an emerging field that explores the flow and deformation properties of systems containing self-propelled particles. These systems exhibit unique behaviors that differ significantly from traditional passive materials.

Key aspects of active matter rheology include self-propulsion effects, where active particles alter fluid properties, leading to unexpected thinning behaviors. The cluster-breaking mechanism, similar to shear thinning in passive systems, disrupts percolating structures. In viscoelastic fluids, active matter modifies particle orientational dynamics due to nonlinear coupling between background shear and disturbance flows.

Active matter rheology has significant implications for materials science, biological systems, and industrial applications. It enables the development of novel materials with tunable properties, enhances understanding of biological processes such as blood flow and bacterial biofilms, and offers potential advancements in food processing, pharmaceuticals, and advanced manufacturing.

Rheology in active matter, bridging non-equilibrium physics, fluid dynamics, and materials science, opens new avenues for designing adaptive and reconfigurable materials with promising research and application potential, including microrobots for targeted drug delivery and microsurgery.

Tuning Shear Rheology through Active Dopants. Amir Shee, Ritwik Bandyopadhyay, and Haicen Yue. PREPRINT , (submitted)

Novel dynamics in dense active matter

Dense active matter systems exhibit a rich array of emergent dynamics and collective behaviors arising from the interplay between particle interactions, self-propulsion, and crowding effects. Dynamical phase transitions occur, such as flocking transitions and glassy dynamics at high densities.

Dense active matter dynamics have significant implications for understanding biological systems, soft matter physics, and complex fluids. They provide insights into collective cell behavior, bacterial colonies, and tissue dynamics. In materials science, these studies enable the development of novel adaptive materials and self-organizing systems.

Research in dense active matter dynamics, bridging non-equilibrium statistical physics, soft condensed matter, and biophysics, opens new avenues for understanding emergent phenomena and designing materials with unique properties. Potential applications include synthetic active materials, microfluidic devices, and understanding complex biological processes like embryonic development and cancer metastasis.

Collective dynamics of densely confined active polar disks with self- and mutual alignment. Weizhen Tnag*, Yating Zheng*, Amir Shee, Gouzheng Lin, Zhangang Han, Pawel Romanczuk, and Cristián Huepe. PREPRINT , RESEARCH ARTICLE
Self-Aligning Polar Active Matter. Paul Baconnier, Olivier Dauchot, Vincent Démery, Gustavo Düring, Silke Henkes, Cristián Huepe, and Amir Shee. PREPRINT , Review Article
Emergent mesoscale correlations in active solids with noisy chiral dynamics. Amir Shee, Silke Henkes, and Cristián Huepe, Soft Matter 2024, 20, 7865-7869. PREPRINT , RESEARCH ARTICLE
Noise-Induced Quenched Disorder in Dense Active Systems. Guozheng Lin, Zhangang Han, Amir Shee, and Cristián Huepe, Phys. Rev. Lett. 131, 168301. PREPRINT , RESEARCH ARTICLE

Resetting in active systems

We study how resetting influences the behavior of active matter, where particles consume energy to move and interact far from equilibrium. In passive systems resetting, understood as interrupting and restarting the dynamics, can significantly alter search times, steady states, and efficiency. Extending this idea to active systems opens new directions for understanding transport, collective behavior, and the emergence of states. Our work brings together statistical physics and soft matter theory with the aim of developing practical ways to control active materials and design efficient strategies for search and transport in noisy environments.

Steering chiral active Brownian motion via stochastic position-orientation resetting. PREPRINT
Active Brownian particle under stochastic position and orientation resetting in a harmonic trap. Amir Shee, J. Phys. Commun. 9 025003.

PREPRINT , RESEARCH ARTICLE

Exact dynamics in active systems

We develop rigorous analytical methods to precisely calculate statistical properties in various active systems. These methods use Laplace transforms of Fokker-Planck equations to compute exact moments of dynamical variables.

Dynamical metastability and re-entrant localization of trapped active elements with speed and orientation fluctuations. Manish Patel, Amir Shee, and Debasish Chaudhuri, Phys. Rev. Research 7, 013126. PREPRINT , RESEARCH ARTICLE
Impact of torque on active Brownian particle: Exact moments in two and three dimensions, Anweshika Pattanayak, Amir Shee, Debasish Chaudhuri, and Abhishek Chaudhuri. PREPRINT , RESEARCH ARTICLE
Self-propulsion with speed and orientation fluctuation: Exact computation of moments and dynamical bistabilities in displacement. Amir Shee and Debasish Chaudhuri, Phys. Rev. E 105, 054148. PREPRINT , RESEARCH ARTICLE
Active Brownian motion with speed fluctuations in arbitrary dimensions: exact calculation of moments and dynamical crossovers. Amir Shee and Debasish Chaudhuri, Journal of Statistical Mechanics: Theory and Experiment 2022 (1), 013201. PREPRINT , RESEARCH ARTICLE
Active Brownian particles: mapping to equilibrium polymers and exact computation of moments. Amir Shee, Abhishek Dhar, and Debasish Chaudhuri, Soft Matter 16 (20), 4776 - 4787. PREPRINT , RESEARCH ARTICLE