The Shee lab develops ab initio electronic structure methods for correlated molecular and condensed matter systems, utilizing both stochastic approaches on classical devices and algorithms for quantum computation. A fundamental aim is to understand strong correlation and the chemical and physical phenomena that it gives rise to. In parallel, we are actively developing scalable electronic structure models to provide quantitative insights into these systems.
Phaseless auxiliary-field quantum Monte Carlo (ph-AFQMC) has demonstrated remarkable accuracy for a wide variety of transition metal-containing systems exhibiting both weak and strong correlations. The low-polynomial scaling of the method's computational cost with respect to system size and its suitability for massive parallelization enable its application to chemical systems beyond the reach of, e.g., coupled cluster models. We are pursuing a number of methodological advances that have the potential to position ph-AFQMC as a true "gold standard" method for ground and excited electronic states, focusing on both energies and properties with the goal of making connections with experiments. One exciting theme that has emerged from our recent investigations of the phaseless constraint and the role of the trial wavefunction is that chemical intuition (combined with efficient algorithms) is key, especially in the accurate modeling of strongly correlated states.
We value and welcome opportunities to collaborate with experimentalists, at Rice and beyond.