Controlling chemical reactions of a single particle

TL;DR

This paper demonstrates quantum state control over a single trapped ion and ultracold atoms to tune chemical reaction rates, revealing hyperfine effects and reaction dynamics at the quantum level.

Contribution

It introduces experimental methods to control and observe chemical reactions at the single-particle quantum level, advancing quantum chemistry and reaction control techniques.

Findings

Hyperfine interaction influences reaction rates and branching ratios.

Reaction kinematics can be monitored at the single-particle level.

Quantum state control enables tuning of chemical reaction pathways.

Abstract

The control of chemical reactions is a recurring theme in physics and chemistry. Traditionally, chemical reactions have been investigated by tuning thermodynamic parameters, such as temperature or pressure. More recently, physical methods such as laser or magnetic field control have emerged to provide completely new experimental possibilities, in particular in the realm of cold collisions. The control of reaction pathways is also a critical component to implement molecular quantum information processing. For these undertakings, single particles provide a clean and well-controlled experimental system. Here, we report on the experimental tuning of the exchange reaction rates of a single trapped ion with ultracold neutral atoms by exerting control over both their quantum states. We observe the influence of the hyperfine interaction on chemical reaction rates and branching ratios, and monitor the kinematics of the reaction products. These investigations advance chemistry with single trapped particles towards achieving quantum-limited control of chemical reactions and indicate limits for buffer gas cooling of single ion clocks.