Letter abstract

Nature Physics 6, 265 - 270 (2010)
Published online: 21 February 2010 | doi:10.1038/nphys1533

Subject Categories: Atomic and molecular physics | Optical physics

An ultracold high-density sample of rovibronic ground-state molecules in an optical lattice

Johann G. Danzl1, Manfred J. Mark1, Elmar Haller1, Mattias Gustavsson1, Russell Hart1, Jesus Aldegunde2, Jeremy M. Hutson2 & Hanns-Christoph Nägerl1


Control over all internal and external degrees of freedom of molecules at the level of single quantum states will enable a series of fundamental studies in physics and chemistry1, 2. In particular, samples of ground-state molecules at ultralow temperatures and high number densities will facilitate new quantum-gas studies3 and future applications in quantum information science4. However, high phase-space densities for molecular samples are not readily attainable because efficient cooling techniques such as laser cooling are lacking. Here we produce an ultracold and dense sample of molecules in a single hyperfine level of the rovibronic ground state with each molecule individually trapped in the motional ground state of an optical lattice well. Starting from a zero-temperature atomic Mott-insulator state5 with optimized double-site occupancy6, weakly bound dimer molecules are efficiently associated on a Feshbach resonance7 and subsequently transferred to the rovibronic ground state by a stimulated four-photon process with >50% efficiency. The molecules are trapped in the lattice and have a lifetime of 8s. Our results present a crucial step towards Bose–Einstein condensation of ground-state molecules and, when suitably generalized to polar heteronuclear molecules, the realization of dipolar quantum-gas phases in optical lattices8, 9, 10.

  1. Institut für Experimentalphysik und Zentrum für Quantenphysik, Universität Innsbruck, Technikerstraße 25, A–6020 Innsbruck, Austria
  2. Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK

Correspondence to: Johann G. Danzl1 e-mail: johann.danzl@uibk.ac.at

Correspondence to: Hanns-Christoph Nägerl1 e-mail: christoph.naegerl@uibk.ac.at