Sensing Atomic Motion from the Zero Point to Room Temperature with Ultrafast Atom Interferometry

TL;DR

This paper introduces an ultrafast atom interferometry technique to sense and characterize atomic motion across a wide energy range, from near-zero to highly excited thermal states, with applications in thermometry and quantum gate characterization.

Contribution

The authors develop a novel ultrafast atom interferometry method capable of measuring atomic motion from the ground state to outside the Lamb-Dicke regime, extending the energy range of quantum state characterization.

Findings

Successfully measured thermal states up to $ar{n} ext{~}10^4$

Characterized a nearly-pure quantum state with $n=1$ phonon

Demonstrated potential for high-energy state extension and ultrafast entangling gate characterization

Abstract

We sense the motion of a trapped atomic ion using a sequence of state-dependent ultrafast momentum kicks. We use this atom interferometer to characterize a nearly-pure quantum state with $n=1$ phonon and accurately measure thermal states ranging from near the zero-point energy to $\bar{n}\sim 10^4$, with the possibility of extending at least 100 times higher in energy. The complete energy range of this method spans from the ground state to far outside of the Lamb-Dicke regime, where atomic motion is greater than the optical wavelength. Apart from thermometry, these interferometric techniques are useful for characterizing ultrafast entangling gates between multiple trapped ions.