Simulating open-system molecular dynamics on analog quantum computers

TL;DR

This paper demonstrates how analog quantum simulators, especially trapped-ion systems with mixed qudit-boson encoding, can efficiently simulate open molecular systems by leveraging native dissipation, surpassing classical and digital quantum methods.

Contribution

It introduces a novel approach to simulate open molecular systems using analog quantum simulators by exploiting native dissipation, enabling longer and more resource-efficient simulations.

Findings

Analog simulators can simulate open molecular systems more efficiently.

Native dissipation can be used as a resource rather than a limitation.

Simulations require fewer resources than classical and digital quantum methods.

Abstract

Interactions of molecules with their environment influence the course and outcome of almost all chemical reactions. However, classical computers struggle to accurately simulate complicated molecule-environment interactions because of the steep growth of computational resources with both molecule size and environment complexity. Therefore, many quantum-chemical simulations are restricted to isolated molecules, whose dynamics can dramatically differ from what happens in an environment. Here, we show that analog quantum simulators can simulate open molecular systems by using the native dissipation of the simulator and injecting additional controllable dissipation. By exploiting the native dissipation to simulate the molecular dissipation -- rather than seeing it as a limitation -- our approach enables longer simulations of open systems than are possible for closed systems. In particular, we show that trapped-ion simulators using a mixed qudit-boson (MQB) encoding could simulate molecules in a wide range of condensed phases by implementing widely used dissipative processes within the Lindblad formalism, including pure dephasing and both electronic and vibrational relaxation. The MQB open-system simulations require significantly fewer additional quantum resources compared to both classical and digital quantum approaches.