Greiner Lab

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Strongly correlated quantum systems

The research goal is to create a very accessible quantum system for experimentally studying strongly correlated many-body states, such as Mott insulator states, anti ferromagnetic states, exotic spin phases, fermionic superfluids etc. This can be achieved with ultracold atoms in multi-dimensional optical lattice potentials. One specific focus of the work is the development of a quantum gas microscope - an evanescent wave optical trap system that allows in-situ imaging of individual atoms with sub micron resolution. This device will allow a new class of experiments, in which excellent spatial addressability is essential. For more information, please contact Markus Greiner.

The new apparatus is based on a magnetic transport method that was pioneered by Greiner et al. in Munich.

M. Greiner , I. Bloch, T. W. Hänsch and T. Esslinger:
Magnetic transport of trapped cold atoms over a large distance
Phys. Rev. A 63, 031401 (2001)

Below you find a short description of this method

New ultracold atom apparatus

 The new apparatus is based on a magnetic transport scheme that provides a large cloud of cold atoms in a science chamber. This description is for the apparatus built in Munich.
 First, we capture a large number of atoms in a single vapor cell magneto-optical trap (MOT).

MOT Cloud of Rubidium atoms in a magneto-optical trap (MOT) inside a vacuum chamber.
 See a movie of the MOT (Munich apparatus):
  • MOT video (divx codec, 368 kB)
  • MOT video (video for windows codec, 752 kB, if it does not play try to save it first)

Then, the atoms are loaded into a magnetic quadrupole trap. The magnetic trap is then moved over about half a meter along an L-shaped path into a UHV chamber, and the quadrupole trap is converted into an Ioffe-type trap (QUIC). In the final trap we apply evaporative cooling until we get a nearly pure condensate of up to 106 atoms.

Ilustration of the transfer-path.

The magnetic trap is smoothly moved by regulating the currents in a chain of quadrupole coil pairs. The heating of the cloud during the transport is negligible since the geometry of the trap does not change during the transport.

Magnetic Coil-path with inset field plot

The main advantage of this new scheme is the totally free optical access to the BEC from all six directions since there is no MOT at the final trapping site. This is an important precondition for the 3D lattice experiments.

... see also papers and review articles on publications page ...