Ultralight dark matter detection with trapped-ion interferometry

TL;DR

This paper proposes using entangled trapped-ion interferometry to detect ultralight dark matter, offering enhanced sensitivity to weak magnetic fields and exploring new parameter space for dark-photon and axion-like particle dark matter.

Contribution

It introduces a novel quantum sensing method using spin-motion entangled ions to probe ultralight dark matter in a previously unexplored mass range.

Findings

Single trapped ion can probe dark-photon parameter space in the 10^{-15} to 10^{-14} eV mass range.

Entanglement enhances sensitivity to weak magnetic fields compared to un-entangled ions.

The method also serves as a complementary probe for axion-like particles in the same mass window.

Abstract

We explore how recent advances in the manipulation of single-ion wave packets open new avenues for detecting weak magnetic fields sourced by ultralight dark matter. A trapped ion in a ``Schr\"odinger cat'' state can be prepared with its spin and motional degrees of freedom entangled and be used as a matter-wave interferometer that is sensitive to the Aharonov-Bohm-like phase shift accumulated by the ion over its trajectory. The result of the spin-motion entanglement is a parametrically-enhanced sensitivity to weak magnetic fields as compared with an un-entangled ion in a trap. Taking into account the relevant boundary conditions, we demonstrate that a single trapped ion can probe unexplored regions of kinetically-mixed dark-photon dark matter parameter space in the $10^{-15}~\text{eV} \lesssim m_{A'} \lesssim 10^{-14}$~eV mass window. We also show how such a table-top quantum device will also serve as a complementary probe of axion-like particle dark matter in the same mass window.