Project B7:
Mixtures in dynamical lattices (2009-2013)
Summary
We plan to experimentally explore new states of matter in mixtures of Lithium and Rubidium atoms that are subject to time dependent optical lattices. The inter species and intra species interactions are tuned with Feshbach resonances. Excitation spectra around the unitary regime near a Feshbach resonance will be recorded with moving 1D lattices (Bragg spectroscopy). The addressed pair combinations include Fermi-Fermi, Bose-Fermi and Bose-Bose mixtures such as: 7Li-87Rb, 6Li-87Rb, 6Li-6Li, 7Li-7Li and 87Rb-87Rb. Dispersion relations and dynamical structure factors will be studied for different interaction strength. Here, the lattice serves as tool for exploring molecules formation and pairing around the unitary regime. A recent prominent example in the physics of cold atoms is singlet pairing and BCS superfluidity of fermionic 6Li. We plan to extend this research to pairing physics with two different species of very different masses. In a second step the lattice will be used not as detection tool but rather to tailor novel dynamic cooperative quantum states. Discontinuous behavior and possibly a novel type of phase transition are expected in a moving 1D optical lattice near the edge of the first Brillouin zone. Similarly, a dynamic 2D optical lattice with locally rotating maxima will by set up and loaded with fermionic Lithium. Recent theoretical work predicts that such a lattice simulates a staggered magnetic flux that induces d-wave symmetry of the order parameter. Dirac points may appear at the edges of the Brillouin zone. Pairing of effective mass less fermions near so called Dirac points seems accessible.
Project leaders
Prof. Dr. Claus Zimmermann, Physikalisches Institut III, Universität Tübingen
Refs & Publications
H. Tomczyk, R.A.W. Maier, and C. Zimmermann"Determination of the 5p fine structure splitting of 6Li by light shift spectroscopy"
Appl. Phys. B 107, 813 (2012); doi: 10.1007/s00340-012-5022-9
R. A. W. Maier, C. Marzok, C. Zimmermann, and Ph. W. Courteille
"Radio-frequency spectroscopy of 6Li p-wave molecules: Towards photoemission spectroscopy of a p-wave superfluid"
Phys. Rev. A 81, 064701 (2010); doi: 10.1103/PhysRevA.81.064701
B. Deh, C. Marzok, S. Slama, C. Zimmermann, and Ph.W. Courteille
"Bragg spectroscopy and Ramsey interferometry with an ultracold Fermi gas"
Appl. Phys. B 97, 387 (2009); doi: 10.1007/s00340-009-3736-0