Nick Mayhall is a Professor of Chemistry at Indiana University. He earned his Ph.D. in theoretical chemistry at Indiana University with Krishnan Raghavachari, where he developed the Molecules-in-Molecules fragmentation approach for large systems, and was a postdoctoral scholar with Martin Head-Gordon at UC Berkeley. He began his independent career at Virginia Tech in 2015, where he received an NSF CAREER Award and an Alfred P. Sloan Fellowship, and returned to Indiana in 2025. His group works at the intersection of electronic structure theory and quantum information science, developing variational quantum algorithms for near-term devices (such as ADAPT-VQE), classical methods for strongly correlated systems (such as TPSCI), and quantum-inspired approaches like the variational double-bracket flow.
Presentation Title:
Using Pauli-based circuit simulation tools for chemistry simulation
Presentation Abstract:
A critical aspect of demonstrating quantum advantage or utility is to rule out the existence of a more efficient classical algorithm for a given problem. This has motivated the development of new classical techniques that can more efficiently simulate quantum circuits on classical hardware. Pauli Propagation is one such technique. In this talk, I will show that these tools can be repurposed as efficient classical computational kernels for important problems relevant to chemistry: estimating ground-state energies of strongly correlated quantum systems.
I will present the variational double-bracket flow (vDBF) algorithm, which uses Pauli Propagation to drive a system variationally toward its ground state. Applied to lattice models and a strongly correlated molecular system, vDBF produces accurate ground-state energies at low computational cost. I will discuss how its accuracy and efficiency compare with established methods such as DMRG, a comparison that is encouraging in some regimes and points to open challenges in others. These results suggest that techniques developed to probe the boundary of quantum advantage may become practical tools for classical many-body chemistry.