We report on the direct control and detection of next-neighbor and longer range spin correlations of cold atoms in optical lattices. Our method relies on the detection of the parity of the spin wavefunction of two neighboring atoms. Phys. Rev. Lett. 105, 265303 (2010)
We have mapped out the phase diagram of a superfluid in a 3D optical lattice at finite temperatures. The experiments are accompanied by full ab initio quantum Monte Carlo simulations with up to 300.000 atoms on more than 10 million lattice sites [Nature Phys. 6, 998 (2010)]. Press release MPQ (deu, eng), MPG (deu). Additional media.
We observed – atom by atom, lattice site by lattice site – a bosonic Mott insulator in an optical lattice. From our images, we fully reconstruct the atom distribution on the lattice and identify individual excitations with high fidelity. Our work will open up new avenues for the manipulation, analysis and applications of strongly interacting quantum gases on a lattice [Nature 467, 68 (2010)]. Press release MPQ (deu, eng), MPG (deu). Article in FAZ, Physics Today. Additional media.
Using the collapses and revivals of coherent matter wave fields we were able to reveal the presence of effective coherent multi-body interactions and the atom number statistics at the sites of an optical lattice. Additional media and press release (deu eng). Original publication at Nature 465, 197-201 (2010)
First BEC on the Boson experiment.
30 Mar '10 - after some time of rebuilding the basic setup, we are happy to welcome the condensate phase back in our lab.
When the interactions between atoms in a gas of particles become increasingly attractive, one expects the gas to intuitively shrink in size. Here we report that a fermionic quantum gas in a a lattice can actually expand for increasing attractive interactions. Science 327, 1621 (2010)