Ultrafast Spin-Motion Entanglement and Interferometry with a Single Atom

TL;DR

This paper demonstrates ultrafast entanglement between an atom's spin and motion within 3 nanoseconds, using laser pulses to create a spin-dependent interferometer, revealing new quantum control capabilities.

Contribution

It introduces a method for ultrafast spin-motion entanglement and interferometry in a single atom, enabling control on nanosecond timescales.

Findings

Achieved spin-motion entanglement in less than 3 ns.

Demonstrated atomic interferometry with spin-dependent momentum kicks.

Observed collapse and revival of spin coherence related to entanglement dynamics.

Abstract

We report entanglement of a single atom's hyperfine spin state with its motional state in a timescale of less than 3 ns. We engineer a short train of intense laser pulses to impart a spin-dependent momentum transfer of +/- 2 hbar k. Using pairs of momentum kicks, we create an atomic interferometer and demonstrate collapse and revival of spin coherence as the motional wavepacket is split and recombined. The revival after a pair of kicks occurs only when the second kick is delayed by an integer multiple of the harmonic trap period, a signature of entanglement and disentanglement of the spin with the motion. Such quantum control opens a new regime of ultrafast entanglement in atomic qubits.