Digital Quantum Simulation of Wavepacket Correlations in a Chemical Reaction

Area of Science:

• Quantum computing
• Computational chemistry
• Chemical dynamics

Background:

• Accurate computation of time-dependent molecular dynamics is crucial for understanding chemical reactions.
• Digital quantum simulation offers a potential pathway for tackling complex quantum chemistry problems.

Purpose of the Study:

• To develop and demonstrate hybrid quantum-classical algorithms for computing time-dependent Møller wavepacket correlation functions.
• To apply these algorithms to the benchmark collinear H + H2 exchange reaction.

Main Methods:

• Encoding wavepackets as qubit states and evolving them using a discretized molecular Hamiltonian.
• Reconstructing wavepacket correlation using a modified Hadamard test and a multi-fidelity estimation (MFE) protocol.
• Utilizing an ancilla-free MFE protocol for reduced circuit depth.

Main Results:

• Quantum-estimated correlation functions quantitatively agree with classical simulations for the H + H2 reaction.
• The simulation accurately reproduced short-time scattering peaks and long-time oscillatory dynamics.
• The ancilla-free MFE protocol achieved comparable results with shallower quantum circuits.

Conclusions:

• Digital quantum circuits can accurately calculate wavepacket correlation functions for chemical reactions.
• Hybrid quantum-classical approaches are promising for simulating complex chemical dynamics.
• The developed methods provide a proof of principle for quantum computation in chemistry.