A general framework for active space embedding methods with applications in quantum computing

Area of Science:

• Quantum computing
• Computational chemistry
• Materials science

Background:

• Hybrid quantum-classical computing offers a powerful approach for simulating complex molecular and periodic systems.
• Accurate modeling of localized electronic states in materials is crucial for understanding their properties.

Purpose of the Study:

• To develop a general framework for hybrid quantum-classical computing applicable to molecular and periodic embedding.
• To demonstrate the framework's capability in predicting optical properties of localized electronic states.

Main Methods:

• Orbital space separation of fragment and environment degrees of freedom.
• Implementation of periodic range-separated Density Functional Theory (DFT) coupled with a quantum circuit ansatz.
• Utilizing variational quantum eigensolver and quantum equation-of-motion algorithms.

Main Results:

• Accurate prediction of optical properties for the neutral oxygen vacancy in magnesium oxide (MgO).
• Demonstrated competitive performance compared to state-of-the-art ab initio methods.
• Excellent agreement with experimental photoluminescence emission peak, despite minor discrepancies in absorption band position.

Conclusions:

• The developed hybrid quantum-classical framework is a viable approach for studying localized electronic states in materials.
• The method shows significant potential for advancing quantum chemistry and materials science simulations.
• Further refinement could improve accuracy for spectral features like absorption bands.