Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Originally published in Science Express on 18 September 2008
Science 10 October 2008:
Vol. 322. no. 5899, pp. 231 - 235
DOI: 10.1126/science.1163861
Prev | Table of Contents | Next

Research Articles

A High Phase-Space-Density Gas of Polar Molecules

K.-K. Ni,1* S. Ospelkaus,1* M. H. G. de Miranda,1 A. Pe'er,1 B. Neyenhuis,1 J. J. Zirbel,1 S. Kotochigova,2 P. S. Julienne,3 D. S. Jin,1{dagger} J. Ye1{dagger}

A quantum gas of ultracold polar molecules, with long-range and anisotropic interactions, not only would enable explorations of a large class of many-body physics phenomena but also could be used for quantum information processing. We report on the creation of an ultracold dense gas of potassium-rubidium (40K87Rb) polar molecules. Using a single step of STIRAP (stimulated Raman adiabatic passage) with two-frequency laser irradiation, we coherently transfer extremely weakly bound KRb molecules to the rovibrational ground state of either the triplet or the singlet electronic ground molecular potential. The polar molecular gas has a peak density of 1012 per cubic centimeter and an expansion-determined translational temperature of 350 nanokelvin. The polar molecules have a permanent electric dipole moment, which we measure with Stark spectroscopy to be 0.052(2) Debye (1 Debye = 3.336 x 10–30 coulomb-meters) for the triplet rovibrational ground state and 0.566(17) Debye for the singlet rovibrational ground state.

1 JILA, National Institute of Standards and Technology (NIST) and University of Colorado, Department of Physics, University of Colorado, Boulder, CO 80309–0440, USA.
2 Physics Department, Temple University, Philadelphia, PA 19122–6082, USA.
3 Joint Quantum Institute, NIST, and University of Maryland, Gaithersburg, MD 20899–8423, USA.

* These authors contributed equally to this work.

{dagger} To whom correspondence should be addressed. E-mail: jin{at}jilau1.colorado.edu (D.S.J.); ye{at}jila.colorado.edu (J.Y.)

Read the Full Text

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)