Counting atoms using interaction blockade in an optical superlattice

TL;DR

This paper demonstrates an interaction blockade effect in ultracold atoms within optical superlattices, enabling precise atom counting and control akin to Coulomb blockade in solid-state systems.

Contribution

It introduces a method to observe and utilize interaction blockade in optical lattices for atom counting and state control, extending concepts from mesoscopic physics to cold atom systems.

Findings

Observation of discrete tunneling resonances in optical superlattices

Ability to determine atom number distribution in different quantum regimes

Controlled manipulation of atom populations in lattice sites

Abstract

We report on the observation of an interaction blockade effect for ultracold atoms in optical lattices, analogous to Coulomb blockade observed in mesoscopic solid state systems. When the lattice sites are converted into biased double wells, we detect a discrete set of steps in the well population for increasing bias potentials. These correspond to tunneling resonances where the atom number on each side of the barrier changes one by one. This allows us to count and control the number of atoms within a given well. By evaluating the amplitude of the different plateaus, we can fully determine the number distribution of the atoms in the lattice, which we demonstrate for the case of a superfluid and Mott insulating regime of 87Rb.