Modeling Strong Light-Matter Coupling in Correlated Systems: State-Averaged Cavity Quantum Electrodynamics Complete...

Area of Science:

• Quantum Chemistry
• Theoretical Chemistry
• Cavity Quantum Electrodynamics

Background:

• Strongly correlated systems interacting with quantized cavity modes present significant theoretical challenges.
• Existing methods like cavity QED generalizations of complete active space configuration interaction and density matrix renormalization group have limitations.

Purpose of the Study:

• To introduce a novel QED extension of state-averaged complete active space self-consistent field theory.
• To incorporate cavity-induced correlations via a second-order orbital optimization framework.

Main Methods:

• Developed a QED extension of state-averaged complete active space self-consistent field theory.
• Implemented using photon number state and coherent state representations.
• Enabled symmetry-free orbital relaxations for polaritonic systems.

Main Results:

• Achieved significantly improved accuracy in modeling ground-state and polariton potential energy surfaces compared to QED-CASCI.
• Reached sub kcal/mol accuracy in potential energy surfaces within much smaller active spaces.
• Demonstrated robust origin invariance in energies with coherent state representation.

Conclusions:

• The new method offers a more robust approach for studying cavity-altered chemical landscapes.
• It provides enhanced accuracy for ground and excited strongly coupled systems.
• This advancement facilitates the study of light-matter interactions in chemistry.