Spectroscopy of ultracold trapped cesium Feshbach molecules

by M. Mark, F. Ferlaino, S. Knoop, J. G. Danzl, T. Kraemer, C. Chin, H.-C. Nägerl, R. Grimm
Abstract:
We explore the rich internal structure of Cs2 Feshbach molecules. Pure ultracold molecular samples are prepared in a CO2-laser trap, and a multitude of weakly bound states is populated by elaborate magnetic-field ramping techniques. Our methods use different Feshbach resonances as input ports and various internal level crossings for controlled state transfer. We populate higher partial-wave states of up to eight units of rotational angular momentum (l-wave states). We investigate the molecular structure by measurements of the magnetic moments for various states. Avoided level crossings between different molecular states are characterized through the changes in magnetic moment and by a Landau-Zener tunneling method. Based on microwave spectroscopy, we present a precise measurement of the magnetic-field-dependent binding energy of the weakly bound s-wave state that is responsible for the large background scattering length of Cs. This state is of particular interest because of its quantum-halo character.
Reference:
Spectroscopy of ultracold trapped cesium Feshbach molecules,
M. Mark, F. Ferlaino, S. Knoop, J. G. Danzl, T. Kraemer, C. Chin, H.-C. Nägerl, R. Grimm,
Phys. Rev. A, volume 76, 2007.
Bibtex Entry:
@article{PhysRevA.76.042514,
  title = {Spectroscopy of ultracold trapped cesium Feshbach molecules},
  author = {Mark, M. and Ferlaino, F. and Knoop, S. and Danzl, J. G. and Kraemer, T. and Chin, C. and Nägerl, H.-C. and Grimm, R.},
  journal = {Phys. Rev. A},
  volume = {76},
  issue = {4},
  pages = {042514},
  numpages = {14},
  year = {2007},
  month = {Oct},
  abstract = {We explore the rich internal structure of Cs2 Feshbach molecules. Pure ultracold molecular samples are prepared in a CO2-laser trap, and a multitude of weakly bound states is populated by elaborate magnetic-field ramping techniques. Our methods use different Feshbach resonances as input ports and various internal level crossings for controlled state transfer. We populate higher partial-wave states of up to eight units of rotational angular momentum (l-wave states). We investigate the molecular structure by measurements of the magnetic moments for various states. Avoided level crossings between different molecular states are characterized through the changes in magnetic moment and by a Landau-Zener tunneling method. Based on microwave spectroscopy, we present a precise measurement of the magnetic-field-dependent binding energy of the weakly bound s-wave state that is responsible for the large background scattering length of Cs. This state is of particular interest because of its quantum-halo character.},
  publisher = {American Physical Society},
  doi = {10.1103/PhysRevA.76.042514},
  url = {http://link.aps.org/doi/10.1103/PhysRevA.76.042514},
  arXiv = {http://arxiv.org/abs/0706.1041}
}