Gaurav Harsha

Research Area Specialist Senior

Computational physicist · Scientific software & HPC

Department of Chemistry, University of Michigan, Ann Arbor

I develop many-body methods and open-source software to understand how temperature, disorder, and relativity shape quantum materials. My work connects electronic-structure theory with predictive simulations, from molecules to solids.

I am the lead developer for the GREEN software package, where I lead implementations of new methods, optimize performance for modern HPC architectures, and train new users in its application.

Academic CV

Recent news

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Talk at the University of Georgia

I presented a talk on “Describing electronic topology using interacting Green’s function” at the Center for Simulational Physics, University of Georgia.

BSE paper published in JCTC

Our work led by Ming Wen combines a self-consistent GW reference with a dynamical screening correction to improve molecular excitation energies.

New quantum impurity solver preprint

Our collaboration led by Yang Yu combines Hamiltonian and diagrammatic methods to improve the accuracy and convergence of quantum impurity calculations.

Talk at ICQC 2026

I presented our work on correlated topological materials using first-principles self-consistent GW at the International Congress on Quantum Chemistry in Berkeley.

Research

A unifying goal is a predictive description of quantum materials beyond idealized zero-temperature, perfectly ordered models. Current directions connect thermal ensembles, relativistic electronic structure, and chemical disorder within systematically improvable many-body approaches.

Thermofield approach maps a thermal density matrix to a temperature-dependent wave function, with proposed applications to adsorption isotherms and phase diagrams.
Beyond the ground state

Thermofield formulations of coupled cluster and related wave-function methods for finite-temperature electronic structure. The focus is on electron correlation, thermal ensembles, and electronic free energies, with applications to adsorption and phase stability.

Thermofield theoryCode
Orbital character exchanges across a band inversionSolid and dashed branches represent different orbital characters, exchanging their energy ordering as strain changes. This is a conceptual schematic, not calculated band data.EnergyStrainOrbital AOrbital B
Correlation, relativity & topology

Correlated topological phases in materials with strong spin–orbit coupling, described using fully self-consistent relativistic GW. Symmetry-resolved Green’s functions connect electronic spectra, orbital character, and band inversion in strain-tunable α-Sn.

Topology preprintRelativistic GW
A disordered lattice mapped to an effective mediumFilled and open lattice sites indicate different local environments. An arrow connects them to an effective medium used to describe disorder.Local environmentsEffective mediumG, Σ
Disorder in quantum materials

First-principles descriptions of disorder using coherent potential approximation with Bloch Gaussian orbitals. The focus is on the interplay of local chemical environments and electronic structure within a Green’s-function framework for materials beyond the perfect crystal.

Poster awardGREEN software

Software

Python C++ CUDA
GREEN Many-Body Packages

An open-source software package for first-principles Green’s function methods in quantum materials. Key contributions:

  • green-mbtools - initialization and post-processing tools for many-body calculations in green-mbpt
  • green-gpu - GPU-accelerated implementations for the GW method.
  • green-mbpt - first-principles GW and GF2 for solid-state systems

I implement many-body methods and GPU acceleration, improve performance, and train users across the group and collaborating institutions. Software paper.

Website
Python Sympy
Drudge and Gristmill

Symbolic algebra and tensor manipulation libraries for quantum many-body theory. Drudge can be used to perform high-order nested commutators of Fermi, Bose, and SU2 operators, which can be simplified and brought into a normal-ordered form automatically.

I actively help in maintaining the package, reviewing pull requests, updating documentation, and keeping the software up-to-date with modern Python environments.

Website
Python Fortran
Finite-temperature CCSD

I developed TFD-CCSD and CANON-TFD, Python/Fortran implementations of thermal coupled cluster and perturbation theory. These tools connect wave-function methods with finite-temperature ensembles.