Polaritonic Coupled Cluster Theory for Unpolarized Cavities Exploiting Point-Group Symmetry

Area of Science:

• Quantum chemistry
• Cavity quantum electrodynamics
• Spectroscopy

Background:

• Strongly coupled light-matter systems are crucial in quantum optics.
• Describing these systems in unpolarized cavities presents theoretical challenges.
• Existing methods often simplify cavity polarization, limiting accuracy.

Purpose of the Study:

• To generalize the quantum electrodynamic coupled cluster (QED-CC) ansatz for unpolarized optical cavities.
• To enable accurate calculations of polaritonic excited states by exploiting symmetry.
• To investigate the excited-state landscapes of aromatic molecules in such cavities.

Main Methods:

• Developed a generalized QED-CC wave function ansatz.
• Explicitly included two perpendicular cavity modes.
• Utilized point-group symmetry for state assignment and targeted calculations.
• Applied the method to benzene, fluorobenzene, azulene, and H2.

Main Results:

• The new ansatz preserves the symmetry of unpolarized cavities.
• Molecules in unpolarized cavities exhibit complex excited-state landscapes with numerous avoided crossings.
• Demonstrated differences in excited-state behavior compared to single-polarization cavities.
• Successfully assigned and calculated polaritonic excited states.

Conclusions:

• The generalized QED-CC ansatz provides a robust framework for studying light-matter interactions in unpolarized cavities.
• Unpolarized cavities significantly alter molecular excited-state properties.
• This work advances the theoretical understanding of cavity quantum electrodynamics and its impact on molecular systems.