Trapped electrons and ions as particle detectors

TL;DR

Electrons and ions trapped with electromagnetic fields can serve as highly sensitive, low-noise detectors for passing charged particles, enabling applications in particle physics, dark matter detection, and quantum computer noise characterization.

Contribution

This work highlights the potential of trapped electron and ion systems as sensitive particle detectors, proposing new applications and detection capabilities beyond traditional uses.

Findings

Can detect energy depositions below ionization scales

Enable sub-eV energy resolution for slow particles

Provide competitive sensitivity to millicharged dark matter

Abstract

Electrons and ions trapped with electromagnetic fields have long served as important high-precision metrological instruments, and more recently have also been proposed as a platform for quantum information processing. Here we point out that these systems can also be used as highly sensitive detectors of passing charged particles, due to the combination of their extreme charge-to-mass ratio and low-noise quantum readout and control. In particular, these systems can be used to detect energy depositions many orders of magnitude below typical ionization scales. As illustrations, we suggest some applications in particle physics. We outline a non-destructive time-of-flight measurement capable of sub-eV energy resolution for slowly moving, collimated particles. We also show that current devices can be used to provide competitive sensitivity to models where ambient dark matter particles carry small electric millicharges $\ll e$. Our calculations may also be useful in the characterization of noise in quantum computers coming from backgrounds of charged particles.