Hamiltonian simulation-based quantum-selected configuration interaction for large-scale electronic structure...

Area of Science:

• Quantum chemistry
• Computational physics
• Quantum computing applications

Background:

• Conventional Quantum-Selected Configuration Interaction (QSCI) relies on preparing high-quality wave functions for accurate quantum chemical calculations.
• This preparation step is a bottleneck, especially for strongly correlated systems.

Purpose of the Study:

• To introduce a novel Hamiltonian simulation-based QSCI (HSB-QSCI) method.
• To overcome the limitations of traditional QSCI by avoiding the need for explicit high-quality approximate wave function preparation.

Main Methods:

• HSB-QSCI samples Slater determinants from quantum states generated via real-time evolution of approximate wave functions.
• Numerical simulations were performed for oligoacenes, phenylene-1,4-dinitrene, and hexa-1,2,3,4,5-pentaene.
• Hardware demonstrations were conducted on an IBM quantum processor for carbyne molecules up to 36 qubits.

Main Results:

• HSB-QSCI successfully calculates energies for both simple and strongly correlated systems.
• The method captured over 99.18% of correlation energies using only ~1% of Slater determinants in 36-qubit systems.
• Demonstrated applicability to molecules requiring significant quantum resources.

Conclusions:

• HSB-QSCI is a robust and efficient method for quantum chemical calculations on current quantum computers.
• The approach significantly reduces the computational burden by efficiently selecting relevant electronic configurations.
• HSB-QSCI shows promise for advancing quantum computing applications in chemistry.