Time-of-Flight Quantum Tomography of Single Atom Motion

TL;DR

This paper demonstrates quantum state tomography of a single atom's motion using time-of-flight imaging combined with coherent evolution in an optical trap, revealing non-classical states through Wigner function negativity.

Contribution

It introduces a novel method for quantum motion tomography that does not rely on spin coupling, enabling characterization of non-classical motional states of single atoms.

Findings

Successfully visualized Wigner function negativity.

Demonstrated access to arbitrary phase space quadratures.

Enabled characterization of non-stationary quantum states.

Abstract

Time of flight is an intuitive way to determine the velocity of particles and lies at the heart of many capabilities ranging from mass spectrometry to fluid flow measurements. Here we show time-of-flight imaging can realize tomography of a quantum state of motion of a single trapped atom. Tomography of motion requires studying the phase space spanned by both position and momentum. By combining time-of-flight imaging with coherent evolution of the atom in an optical tweezer trap, we are able to access arbitrary quadratures in phase space without relying on coupling to a spin degree of freedom. To create non-classical motional states, we harness quantum tunneling in the versatile potential landscape of optical tweezers, and our tomography both demonstrates Wigner function negativity and assesses coherence of non-stationary states. Our demonstrated tomography concept has wide applicability to a range of particles and will enable characterization of non-classical states of more complex systems or massive dielectric particles.