Flexible Ansatz for N-Body Perturbation Theory

Area of Science:

• Quantum Mechanics
• Computational Chemistry
• Theoretical Physics

Background:

• Solving the Schrödinger equation is crucial for understanding quantum systems.
• Existing methods face challenges with complex wave functions and strong correlations.
• A robust perturbation theory framework is needed for arbitrary N-body systems.

Purpose of the Study:

• To develop a novel perturbation theory framework for solving the Schrödinger equation.
• To introduce the Flexible Ansatz for N-body Perturbation Theory (FANPT).
• To enable projective solutions for arbitrary wave functions.

Main Methods:

• Derivation of recursive FANPT expressions.
• Extension to arbitrary orders in the perturbation hierarchy.
• Building upon the Flexible Ansatz for N-body Configuration Interaction (FANCI).

Main Results:

• FANPT provides a framework for projective solutions of the Schrödinger equation.
• Recursive expressions for arbitrary perturbation orders are derived.
• The FANPT equations demonstrate well-behaved solutions across various conditions.

Conclusions:

• FANPT offers a stable and versatile approach for quantum mechanical calculations.
• The method is effective for static correlation-dominated and nonlinear wave functions.
• FANPT advances the computational treatment of N-body quantum systems.