Controlling atom-atom interaction at ultralow temperatures by dc electric fields

We propose a physical mechanism for tuning the atom-atom interaction strength at ultralow temperatures. In the presence of a de electric field the interatomic potential is changed due to the effective dipole-dipole interaction between the polarized atoms. Detailed multichannel scattering calculations reveal features never before discussed for ultracold atomic collisions. We demonstrate that optimal control of the effective atom-atom interactions can be achieved under reasonable laboratory conditions. implications of this research on the physics of atomic Bose-Einstein condensation and on the pursuit fur atomic degenerate fermion gases will be discussed. [S0031-9007(98)07764-3].