Radiofrequency-dressed-state potentials for neutral atoms

Potentials for atoms can be created by external fields acting on properties such as magnetic moment, charge, polarizability, or by oscillating fields that couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronically excited states of an atom with light. Here, we present an extensive experimental analysis of potentials derived from radiofrequency (RF) coupling of electronic ground states. The coupling is magnetic and the vector character allows the design of versatile microscopic state-dependent potential landscapes. Compared with standard magnetic trapping, we find no additional heating or (collisional) loss up to densities of 10(15) atoms cm(-3). We demonstrate robust evaporative cooling in RF potentials, which allows easy production of Bose - Einstein condensates in complex potentials. Altogether, this makes RF dressing a new powerful tool for manipulating ultracold atoms complementary to magnetic trapping and optical dipole potentials.