Related papers: Quantum phases in a resonantly-interacting Bose-Fe…
We produce a heteronuclear quantum degenerate mixture of two bosonic species, $^{87}$Rb and $^{41}$K, in a three-dimensional optical lattice. On raising the lattice barriers, we observe the disapperance of the inference pattern of the…
We investigate the effect of interspecies interaction on a degenerate mixture of bosonic 87Rb and fermionic 40K atoms in a three-dimensional optical lattice potential. Using a Feshbach resonance, the 87Rb-40K interaction is tuned over a…
We study the ground-state phase diagram of a Bose-Fermi mixture loaded in a one-dimensional optical lattice by computing the ground-state fidelity and quantum entanglement. We find that the fidelity is able to signal quantum phase…
We study the ground-state properties of mixtures of strongly interacting bosonic atoms in an optical lattice. Applying a mean-field approximation to the Hubbard model for Bose-Bose mixtures, we calculate the densities and superfluid order…
We combine model mapping, exact spectral bounds, and a quantum Monte Carlo method to study the ground state phases of a mixture of ultracold bosons and spin-polarized fermions in a one-dimensional optical lattice. The exact boundary of the…
We demonstrate a generally applicable technique for mixing two-species quantum degenerate bosonic samples in the presence of an optical lattice, and we employ it to produce low-entropy samples of ultracold 87Rb133Cs Feshbach molecules with…
A mixture of ultracold bosons and fermions placed in an optical lattice constitutes a novel kind of quantum gas, and leads to phenomena, which so far have been discussed neither in atomic physics, nor in condensed matter physics. We discuss…
We have studied mixtures of fermionic $^{40}$K and bosonic $^{87}$Rb quantum gases in a three-dimensional optical lattice. We observe that an increasing admixture of the fermionic species diminishes the phase coherence of the bosonic atoms…
We study an atomic Bose-Fermi mixture in an optical lattice which is confined using an optical trap. We obtain the Mott ground states of such a system in the limit of deep optical lattice and discuss the effect of quantum fluctuations on…
The zero-temperature phase diagram of a binary mixture of bosonic and fermionic atoms in an one-dimensional optical lattice is studied in the framework of the Bose-Fermi-Hubbard model. By exact numerical solution of the associated…
This PhD tutorial article is a review of our experiments on heteronuclear quantum gas mixtures at the University of Hamburg. We introduce basic properties of trapped Fermi-Bose mixtures and demonstrate the achievement of large quantum…
Advances in pure optical trapping techniques now allow the creation of degenerate Bose gases with internal degrees of freedom. Systems such as ${}^{87}$Rb, $^{39}$K or ${}^{23}$Na in the $F=1$ hyperfine state offer an ideal platform for…
We discuss the theory of mixtures of Bosonic and Fermionic atoms in periodic potentials at zero temperature. We derive a general Bose--Fermi Hubbard Hamiltonian in a one--dimensional optical lattice with a superimposed harmonic trapping…
The ground state phase diagram of the one-dimensional Bose-Fermi Hubbard model is studied in the canonical ensemble using a quantum Monte Carlo method. We focus on the case where both species have half filling in order to maximize the…
We demonstrate tuning of interactions between fermionic 40K and bosonic 87Rb atoms by Feshbach resonances and access the complete phase diagram of the harmonically trapped mixture from phase separation to collapse. On the attractive side of…
Motivated by experiments on heteronuclear Feshbach resonances in Bose mixtures, we investigate s-wave pairing of two species of bosons in an optical lattice. The zero temperature phase diagram supports a rich array of superfluid and Mott…
We study the dynamics of coupled dipolar oscillations in a Fermi-Bose mixture of $^{40}$K and $^{87}$Rb atoms. This low-energy collective mode is strongly affected by the interspecies interactions. Measurements are performed in the…
We study the ground state and the thermal phase diagram of a two-species Bose-Hubbard model, with $U(1)\times \mathbb{Z}_2$ symmetry, describing atoms and molecules on a 2D optical lattice interacting via a Feshbach resonance. Using quantum…
Engineering long-range interacting spin systems with ultra cold atoms offers the possibility to explore exotic magnetically ordered phases in strongly-correlated scenarios. Quantum gases in optical cavities provide a versatile experimental…
We create atom-molecule superpositions in a Bose-Fermi mixture of Rb-87 and K-40 atoms. The superpositions are generated by ramping an applied magnetic field near an interspecies Fano-Feshbach resonance to coherently couple atom and…