Metastable Feshbach Molecules in High Rotational States

by S. Knoop, M. Mark, F. Ferlaino, J. G. Danzl, T. Kraemer, H.-C. Nägerl, R. Grimm

Abstract:

We experimentally demonstrate Cs2 Feshbach molecules well above the dissociation threshold, which are stable against spontaneous decay on the time scale of 1 s. An optically trapped sample of ultracold dimers is prepared in a high rotational state and magnetically tuned into a region with a negative binding energy. The metastable character of these molecules arises from the large centrifugal barrier in combination with negligible coupling to states with low rotational angular momentum. A sharp onset of dissociation with increasing magnetic field is mediated by a crossing with a lower rotational dimer state and facilitates dissociation on demand with a well-defined energy.

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Reference:

Metastable Feshbach Molecules in High Rotational States,
S. Knoop, M. Mark, F. Ferlaino, J. G. Danzl, T. Kraemer, H.-C. Nägerl, R. Grimm,
Phys. Rev. Lett., volume 100, 2008.

Bibtex Entry:

@article{PhysRevLett.100.083002,
  title = {Metastable Feshbach Molecules in High Rotational States},
  author = {Knoop, S. and Mark, M. and Ferlaino, F. and Danzl, J. G. and Kraemer, T. and N"agerl, H.-C. and Grimm, R.},
  journal = {Phys. Rev. Lett.},
  volume = {100},
  issue = {8},
  pages = {083002},
  numpages = {4},
  year = {2008},
  month = {Feb},
  abstract = {We experimentally demonstrate Cs2 Feshbach molecules well above the dissociation threshold, which are stable against spontaneous decay on the time scale of 1 s. An optically trapped sample of ultracold dimers is prepared in a high rotational state and magnetically tuned into a region with a negative binding energy. The metastable character of these molecules arises from the large centrifugal barrier in combination with negligible coupling to states with low rotational angular momentum. A sharp onset of dissociation with increasing magnetic field is mediated by a crossing with a lower rotational dimer state and facilitates dissociation on demand with a well-defined energy.},
  publisher = {American Physical Society},
  doi = {10.1103/PhysRevLett.100.083002},
  url = {http://link.aps.org/doi/10.1103/PhysRevLett.100.083002},
  arXiv = {http://arxiv.org/abs/0710.4052}
}