Large atoms in large magnetic fields

P. van der Straten, Harold J. Metcalf

Kent S. Johnson, J Dagdigian Paul, A. P. Chu +3 more

Many atom interferometer applications would benefit from large angle atomic beamsplitters with narrow distributions. The interaction between a magnetic field and two standing wave laser fields can provide such a beamsplitter.1 Unfortunately, the required magnetic fields are undesirable in many interferometer applications, and few atomic systems have a suitable transition.

Yuqing Li, Guosheng Feng, Rundong Xu +7 more

We report a detailed study of effective magnetically levitated loading of cold atoms in a crossed dipole trap: an appropriate magnetic field gradient precisely compensates for the destructive gravitational force of the atoms and an additional bias field simultaneously eliminates the antitrapping potential induced by the magnetic field gradient. The magnetic levitation is required for a large-volume crossed dipole trap to form a shallow but very effective loading potential, making it a promising method for loading and trapping more cold atoms. For cold cesium atoms in the $F=3, mF=3$ state prepared by three-dimensional degenerated Raman sideband cooling, a large number of atoms $\ensuremath{\sim}3.2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ have been loaded into a large-volume crossed dipole trap with the help of the magnetic levitation technique. The dependence of the number of atoms loaded and trapped in the dipole trap on the magnetic field gradient and bias field, respectively, is in good agreement with the theoretical analysis. The optimum magnetic field gradient of 31.13 G/cm matches the theoretical value of 31.3 G/cm well. This method can be used to obtain more cold atoms or a large number of Bose-Einstein condensation atoms for many atomic species in high-field seeking states.

Paul Ewart

Georg A. Raithel, M. Fauth, HERBERT WALTHER

This paper reports on the evidence for large permanent electric-dipole moments of Rydberg atoms in crossed electric and magnetic fields. It was found that the dipole moments have a large value if the scaled electric-field strength \ensuremath{\epsilon}=${\mathit{EB}}^{\mathrm{\ensuremath{-}}4/3}$ has the value \ensuremath{\epsilon}\ensuremath{\approxeq}0.75 (with electric- and magnetic-field strengths E and B in atomic units). The experimental technique employed to determine the atomic dipole moment was to add a slight inhomogeneity to the electric field and to measure the deflection of the atoms, this deflection being proportional to the field inhomogeneity and the atomic dipole moment. In order to discuss the experimental results, different theoretical approaches to the E\ifmmode\times\else\texttimes\fi{}B problem are reviewed. The occurrence of Rydberg atoms with large dipole moments can be explained as being caused by a distinct type of classical orbit.

Jamie Ryan Gardner