Department of Computational and Data Sciences
Department Seminar
Speaker : Dr. Abhiraj Sharma, Postdoctoral Researcher, LBNL, California, U.S.A.
Title : “Large-scale real-space finite-difference based electronic structure calculations”
Date & Time : February 13, 2024, 11:30 AM
Venue : # 102, CDS Seminar Hall
ABSTRACT
Electronic structure methods are widely employed for understanding the quantum mechanics driven behavior of material systems including but not limited to flexo electricity, spintronics, piezoelectricity, and thermal conductivity. Among these methods, Kohn-Sham density functional theory (DFT) has emerged as the cornerstone of material’s research owing to its high accuracy-to-cost ratio in comparison to other such ab initio methods. Despite significant advancements, Kohn-Sham calculations are still very expensive which limits the length and time scales accessible to first-principles investigation.
In this talk, I will present on the recent developments in real-space finite-difference DFT resulting in a significant reduction in the computational cost and wall times associated with Kohn-Sham calculations, opening avenues for studying material systems considered intractable before. In particular, we have achieved more than an order of magnitude speedup in comparison to state-of-the-art DFT implementations by utilizing the computational locality in finite-difference method, concepts of symmetry, and high performance hybrid computing architectures. I will also discuss our recent efforts on accelerating the quantum molecular dynamics (QMD) simulations by incorporating a kernel method based machine-learned force field (MLFF) scheme trained in an online manner, resulting in more than two orders of magnitude speedups. Finally, I will discuss the computational bottlenecks associated with calculating higher order properties of material systems including superconductivity and thermal conductivity and our ongoing work on developing a large-scale real-space formulation of density functional perturbation theory (DFPT) to overcome it, opening avenues for a plethora of new applications with technological implications.
BIOGRAPHY
Abhiraj Sharma received his B.Tech degree in Civil Engineering from IIT Roorkee in 2016. Afterwards, he completed his M.S. and PhD from Georgia Institute of Technology in 2022. Currently, he is working as a Postdoctoral Researcher in the Physical and Life Sciences division at Lawrence Livermore National Lab. His research is in the broad area of material physics and mechanics with the focus on the development of mathematical and computational tools to enable the first-principles study of mechanics in material which can potentially lead to the discovery of materials with fascinating properties.
Host Faculty: Dr. Phani Motamarri
ALL ARE WELCOME
