11 research outputs found
Rubidium-87 Bose-Einstein condensate in an optically plugged quadrupole trap
We describe an experiment to produce 87Rb Bose-Einstein condensates in an
optically plugged magnetic quadrupole trap, using a blue-detuned laser. Due to
the large detuning of the plug laser with respect to the atomic transition, the
evaporation has to be carefully optimized in order to efficiently overcome the
Majorana losses. We provide a complete theoretical and experimental study of
the trapping potential at low temperatures and show that this simple model
describes well our data. In particular we demonstrate methods to reliably
measure the trap oscillation frequencies and the bottom frequency, based on
periodic excitation of the trapping potential and on radio-frequency
spectroscopy, respectively. We show that this hybrid trap can be operated in a
well controlled regime that allows a reliable production of degenerate gases.Comment: 13 pages, 8 figure
Recent developments in trapping and manipulation of atoms with adiabatic potentials
A combination of static and oscillating magnetic fields can be used to ‘dress’ atoms with radio-frequency (RF), or microwave, radiation. The spatial variation of these fields can be used to create an enormous variety of traps for ultra-cold atoms and quantum gases. This article reviews the type and character of these adiabatic traps and the applications which include atom interferometry and the study of low-dimensional quantum systems. We introduce the main concepts of magnetic traps leading to adiabatic dressed traps. The concept of adiabaticity is discussed in the context of the Landau–Zener model. The first bubble trap experiment is reviewed together with the method used for loading it. Experiments based on atom chips show the production of double wells and ring traps. Dressed atom traps can be evaporatively cooled with an additional RF field, and a weak RF field can be used to probe the spectroscopy of the adiabatic potentials. Several approaches to ring traps formed from adiabatic potentials are discussed, including those based on atom chips, time-averaged adiabatic potentials and induction methods. Several proposals for adiabatic lattices with dressed atoms are also reviewed