Research

 

Our group works on the boundary of chemistry, physics, and materials science. We develop new theoretical approaches to understand many-body interactions in quantum materials, low dimensional semiconductors, molecules, and plasmonic interfaces. Quantum interactions in these systems were often deemed untractable by conventional theoretical techniques. We are pioneering new methods that break the current computational limitations and apply advanced quantum many-body theory on realistic nanoscale systems. 

 

Our group closely collaborates with experimental colleagues in the Quantum Foundry at UCSB.

 
 

Method Development

 

We specialize in the development of stochastic techniques to compute the dynamics of electron-electron interactions. We rely on many-body diagrammatic methods that are in quantitative agreement with experiments

 

Typical implementations are time-consuming and can be applied only to small systems. We instead employ efficient Monte-Carlo sampling of wavefunctions and decomposition of quantum mechanical operators. The resulting computational techniques scale linearly with the system size, and we readily treat systems with thousands of atoms.

 

Recently, we have introduced a new method to compute non-local vertex corrections - a step beyond widely used GW approximation. This approach significantly improves the agreement between theoretical predictions and experiments.

 

 

Many-body interactions in (quantum) materials   

We are interested in quantum interactions in real systems: low dimensional materials, molecular assemblies, interfaces, and surfaces. In particular, we study many-body interactions in systems that are promising candidates as qubit hosts for quantum computing and/or which exhibit emergent phenomena. 

 

We are investigating quasiparticle localization in twisted 2D semiconductors. The localized electronic states are hotly-debated for their unique quantum mechanical properties associated with strong correlation and superconductivity.

 

Finally, we study the effects of non-local electronic correlation in molecular assemblies and van der Waals heterostructures.