Quantum state preparation and control of single molecular ions

TL;DR

This paper proposes a novel quantum-limited method combining mass spectrometry and Raman spectroscopy for preparing and controlling a wide range of molecular ions in pure quantum states, enabling advanced molecular studies.

Contribution

It introduces a new technique that connects molecular ions to ground-state rotational states while using a co-trapped atomic ion for entropy removal and information extraction.

Findings

Potential for preparing various molecular ions in pure quantum states

Enables precise molecular property measurements

Facilitates fundamental physics tests

Abstract

Preparing molecules at rest and in a highly pure quantum state is a long standing dream in chemistry and physics, so far achieved only for a select set of molecules in dedicated experimental setups. Here, a quantum-limited combination of mass spectrometry and Raman spectroscopy is proposed that should be applicable to a wide range of molecular ions. Excitation of electrons in the molecule followed by uncontrolled decay and branching into several lower energy states is avoided. Instead, the molecule is always connected to rotational states within the electronic and vibrational ground-state manifold, while a co-trapped atomic ion provides efficient entropy removal and allows for extraction of information on the molecule. The outlined techniques might enable preparation, manipulation and measurement of a large multitude of molecular ion species with the same instrument, with applications including, but not limited to, precise determination of molecular properties and fundamental tests of physics.