Single-atom imaging of fermions in a quantum-gas microscope

Abstract

Imaging individual atoms in an optical lattice with single-site resolution has so far only been possible for bosonic species, but thanks to electromagnetically-induced-transparency cooling fermionic species can now also be imaged. Single-atom-resolved detection in optical lattices using quantum-gas microscopes1,2 has enabled a new generation of experiments in the field of quantum simulation. Although such devices have been realized with bosonic species, a fermionic quantum-gas microscope has remained elusive. Here we demonstrate single-site- and single-atom-resolved fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas microscope set-up, using electromagnetically-induced-transparency cooling3,4. We detected on average 1,000 fluorescence photons from a single atom within 1.5 s, while keeping it close to the vibrational ground state of the optical lattice. A quantum simulator for fermions with single-particle access will be an excellent test bed to investigate phenomena and properties of strongly correlated fermionic quantum systems, allowing direct measurement of ordered quantum phases5,6,7,8,9 and out-of-equilibrium dynamics10,11, with access to quantities ranging from spin–spin correlation functions to many-particle entanglement12.