Sympathetic cooling of a trapped proton mediated by an LC circuit

TL;DR

This paper demonstrates a novel method for sympathetically cooling a trapped proton using laser-cooled ions via a superconducting LC circuit, enabling remote cooling over 9 cm and broadening applications in fundamental physics and antimatter research.

Contribution

It introduces a new technique for sympathetic cooling of trapped particles over a distance using an LC circuit, extending quantum control to previously inaccessible particles.

Findings

Successfully cooled a single proton via an LC circuit

Achieved cooling of a macroscopic LC circuit mode with laser-cooled ions

Demonstrated remote sympathetic cooling over 9 cm distance

Abstract

Efficient cooling of trapped charged particles is essential to many fundamental physics experiments, to high-precision metrology, and to quantum technology. Until now, sympathetic cooling has required close-range Coulomb interactions, but there has been a sustained desire to bring laser-cooling techniques to particles in macroscopically separated traps, extending quantum control techniques to previously inaccessible particles such as highly charged ions, molecular ions and antimatter. Here we demonstrate sympathetic cooling of a single proton using laser-cooled Be+ ions in spatially separated Penning traps. The traps are connected by a superconducting LC circuit that enables energy exchange over a distance of 9 cm. We also demonstrate the cooling of a resonant mode of a macroscopic LC circuit with laser-cooled ions and sympathetic cooling of an individually trapped proton, reaching temperatures far below the environmental temperature. Notably, as this technique uses only image-current interactions, it can be easily applied to an experiment with antiprotons, facilitating improved precision in matter-antimatter comparisons and dark matter searches.