Quantum Information Orbitals (QIO): Unveiling Intrinsic Many-Body Complexity by Compressing Single-Body Triviality.

Area of Science:

• Quantum chemistry
• Computational physics
• Materials science

Background:

• Strongly correlated electron systems present significant challenges in accurately describing their complex many-body wave functions.
• Identifying an optimal single-particle orbital basis is crucial for reducing computational complexity but remains a difficult problem.

Purpose of the Study:

• To introduce a novel approach for quantifying and minimizing the complexity of many-body wave functions in electron systems.
• To develop an iterative scheme for orbital optimization using tailored coupled cluster singles and doubles (TCCSD).

Main Methods:

• Minimizing total orbital correlation via orbital rotations to reveal intrinsic wave function complexity.
• An iterative optimization scheme using the tailored coupled cluster singles and doubles (TCCSD) ansatz to refine orbitals.
• Applying the optimized orbitals to improve the accuracy of wave function and energy calculations.

Main Results:

• Total orbital correlation quantifies the intrinsic complexity of the wave function after minimization.
• Optimized orbitals significantly enhance the ability of the limited TCCSD ansatz to capture essential many-body information.
• Demonstrated substantial improvements in predicting potential energy curves for strongly correlated C2 and Cr2 molecules.

Conclusions:

• Minimizing total orbital correlation offers a universal scheme for simplifying complex wave functions.
• The proposed iterative orbital optimization method enhances the predictive power of quantum chemical calculations.
• This approach shows promise for accurately modeling challenging strongly correlated electron systems.