Ab initio molecular dynamics on quantum computers

Area of Science:

• Quantum Computing
• Computational Chemistry
• Materials Science

Background:

• Ab initio molecular dynamics (AIMD) simulates molecular behavior at finite temperatures using electronic structure calculations.
• Current AIMD methods require significant computational resources, limiting the study of complex systems.
• Noisy Intermediate-Scale Quantum (NISQ) computers offer potential for accelerating scientific discovery.

Purpose of the Study:

• To develop and demonstrate a hybrid quantum-classical approach for AIMD simulations on NISQ devices.
• To enable the calculation of molecular energies using quantum algorithms within an AIMD framework.
• To overcome the limitations of current quantum hardware for calculating energy gradients.

Main Methods:

• Utilizing the Variational Quantum Eigensolver (VQE) for electronic energy calculations on a quantum computer.
• Employing numerical methods (finite differences, Hellmann-Feynman theorem, correlated sampling) for gradient computation, avoiding the need for fault-tolerant quantum hardware.
• Integrating quantum energy calculations with classical gradient computations for a hybrid AIMD approach.

Main Results:

• Successfully performed AIMD simulations for the H2 molecule on IBM quantum devices.
• Validated the method's applicability to larger molecules using full configuration interaction (FCI) wave functions.
• Demonstrated a viable pathway for quantum-enhanced molecular dynamics on current quantum hardware.

Conclusions:

• The developed hybrid quantum-classical AIMD method is a promising approach for NISQ-era computers.
• This technique can be extended to study larger and more complex molecular systems as quantum hardware and noise mitigation improve.
• This work paves the way for leveraging quantum computation in molecular dynamics simulations.