Proofs that the Gerber Statistic is Positive Semidefinite
In this brief note, we prove that both forms of the Gerber statistic introduced in Gerber et al. (2022) are positive semi-definite.
q-fin.PM↗
arXiv subjects
P. Ernst
Publications and source records attributed to P. Ernst.
Ultracold heteronuclear molecules in a 3D optical lattice
We report on the creation of ultracold heteronuclear molecules assembled from fermionic 40K and bosonic 87Rb atoms in a 3D optical lattice. Molecules are produced at a heteronuclear Feshbach resonance both on the attractive and the repulsive side of the resonance. We precisely determine the binding energy of the heteronuclear molecules from rf spectroscopy across the Feshbach resonance. We characterize the lifetime of the molecular sample as a function of magnetic field and measure between 20 and 120ms. The efficiency of molecule creation via rf association is measured and is found to decrease as expected for more deeply bound molecules.
cond-mat.stat-mech↗
Localization of bosonic atoms by fermionic impurities in a 3d optical lattice
We observe a localized phase of ultracold bosonic quantum gases in a 3-dimensional optical lattice induced by a small contribution of fermionic atoms acting as impurities in a Fermi-Bose quantum gas mixture. In particular we study the dependence of this transition on the fermionic 40K impurity concentration by a comparison to the corresponding superfluid to Mott insulator transition in a pure bosonic 87Rb gas and find a significant shift in the transition parameter. The observed shift is larger than expected based on a mean-field argument, which is a strong indication that disorder-related effects play a significant role.
cond-mat.stat-mech↗