Efficient DMRG-Based Methods for Advancing Polaritonic Chemistry in Strongly Correlated Regimes

This grant project focuses on the development of new computational methods based on the Density Matrix Renormalization Group (DMRG) method for the field of polaritonic chemistry. Polaritonic chemistry deals with the interactions between molecules and quantum fields, such as photonic modes in resonant cavities. The goal of the project is to develop advanced computational tools for the detailed study of the electronic structure of molecules in strong coupling with these quantum fields. The project aims to adapt and extend the DMRG method for efficient simulations of molecules in a polaritonic environment. Molecules in cavities interact intensively with photons, creating hybrid states of light and matter, known as polaritons. Due to these strongly interacting photons, it is possible to alter the properties of molecules or even influence the course of chemical reactions. Despite the rapid development of this modern field, there are currently no methods suitable for studying molecules with strongly correlated electrons in resonant cavities. Molecules with strongly correlated electrons and materials based on them represent long-term challenges in computational chemistry. They also include substances with high socio-economic significance, such as certain catalysts, active sites of important enzymes, and high-temperature superconductors. Therefore, the development of new theoretical methods for accurate calculations of their electronic structure is extremely important. The DMRG method, which we have been developing for a long time, is known for its ability to efficiently capture strong correlations between electronic degrees of freedom, which is key to correctly describing the dynamics and energy spectra in these systems. Within the framework of the proposed project, we will extend our massively parallel implementation of the quantum chemical DMRG method for multi-model Hamiltonians, where not only electrons but also photons will be described quantum mechanically. In collaboration with international partners, we will extend this method to the relativistic regime, allowing us to tune frequencies to spin excitations and potentially influence the magnetic properties of molecules. Finally, we will develop a time-dependent version of these methods, extending the range of their application in polaritonic chemistry. The proposed computational procedures will be optimized for parallel computing architectures to enable computationally intensive simulations on the most modern supercomputers. The result of the project will be unique and highly efficient computational tools that will allow the theoretical study of strongly correlated molecules, such as complex transition metal complexes or multiradical polycyclic aromatic hydrocarbons in the environment of resonant cavities, which is an area practically unexplored and with high potential. The project builds on successful collaboration with two American institutions: Pacific Northwest National Laboratory (PNNL) and the University of California, Santa Barbara (UCSB). Achieving the ambitious goals of this project will be possible thanks to the significant synergy of all participating parties.