Fragment, Entangle, and Consolidate: Strong Correlation through Bifold Quantum Circuits

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Quantum Computing

Background:

• Accurate simulation of strong electronic correlation is crucial for understanding chemical phenomena.
• Near-term variational quantum algorithms (VQAs) offer scalability but struggle with multireference effects.
• Challenges in simulating strong correlation limit the rational design of new molecules.

Purpose of the Study:

• To introduce a general and customizable scheme for handling strong electronic correlation.
• To improve the accuracy and scalability of quantum algorithms for quantum chemistry.
• To enable the exploration of novel chemical space through advanced simulations.

Main Methods:

• A hybrid quantum scheme based on problem decomposition, entanglement buildup, and consolidation.
• Utilizing hardware-efficient ansatze for entangled subsystem preparation.
• Incorporating dynamic correlation via a unitary coupled cluster framework with specific ansatze.
• Employing a hybrid architecture with separate ansatze for different correlation degrees.

Main Results:

• The proposed scheme demonstrates encouraging accuracy and flexibility for strongly correlated systems.
• Efficient construction of multireference states while respecting hardware topology.
• Balanced capture of various correlation degrees using a hybrid architecture.
• The method shows potential for resource-efficient quantum simulations.

Conclusions:

• The developed scheme effectively addresses strong electronic correlation in quantum chemistry.
• It offers a scalable and flexible approach for near-term quantum devices.
• This work paves the way for exploring quantum algorithms in complex chemical systems.
• The method shows promise for advancing rational molecular design.