Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice

TL;DR

This paper reports the preparation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice using nanofiber-guided homodyne interferometry, achieving noise reduction below the shot noise level.

Contribution

It introduces a method for generating and measuring sub-Poissonian atom number distributions in a 1D lattice with high precision using nanofiber-based homodyne detection.

Findings

Achieved -14 dB noise reduction below Poissonian level.

Real-time atom number measurement with ±8 atom precision.

Potential for generating entangled and spin-squeezed atomic states.

Abstract

We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance $-14$ dB below the Poissonian noise level. A mesoscopic ensemble containing a few thousand atoms is trapped in the evanescent field of a nanofiber. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe. Strong coupling of the evanescent probe guided by the nanofiber allows for a real-time measurement with a precision of $\pm 8$ atoms on an ensemble of some $10^3$ atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum non-demolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice.