The aspect ratio <em>W_x</em>/<em>W_y</em>, of the atomic cloud for various expansion times after releasing from the quadrupole magnetic trap and hybrid trap with a holding time of 2 s

<p><strong>Figure 1.</strong> The aspect ratio <em>W_x</em>/<em>W_y</em>, of the atomic cloud for various expansion times after releasing from the quadrupole magnetic trap and hybrid trap with a holding time of 2 s. <em>W_x</em> and <em>W_y</em> are the cloud size along the <em>x</em>- and <em>y</em>-axis respectively.</p> <p><strong>Abstract</strong></p> <p>We report the rapid accelerated thermalization of potassium (³⁹K) atoms loaded in a magnetic trap, in the presence of a single dipole trap beam. More than an order of magnitude reduction in the thermalization time, to less than a second, is observed with the focused off-resonant beam occupying only 0.01% of the volume of the magnetic trap. A new method for testing for thermalization of relatively hot clouds is devised. The cold atoms are loaded from a magneto-optical trap (MOT) of ³⁹K that has gone through a compressed MOT and sub-Doppler cooling stage. The atoms are prepared in the magnetically stretched |<em>F</em> = 2, <em>m_F</em> = 2〉 state prior to loading into the hybrid trap. We also report a direct loading of ³⁹K atoms, prepared in the state |<em>F</em> = 1〉, into a single beam dipole trap.