Center for Ultracold Atoms and Quantum Gases, IExP and IQOQI, Innsbruck
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ERBIUM NEWS
We have studied the scattering behavior of ultracold Er atoms and observed an enormous number of Fano-Feshbach scattering resonances and demonstrate high correlation in the spectra, underlying chaotic scattering between the particles. This work, now published in NATURE, is a joint effort between our group, John L. Bohn from JILA (Boulder, Colorado), and the team of Svetlana Kotochigova at Temple University (USA). Nice media coverage (in italian) from the MEDIA INAF. [more]
ERBIUM NEWS
We report on the creation of the first degenerate dipolar Fermi gas of erbium atoms. We force evaporative cooling in a fully spin-polarized sample down to temperatures as low as 0.2 times the Fermi temperature. The strong magnetic dipole-dipole interaction enables elastic collisions between identical fermions even in the zero-energy limit. The measured elastic scattering cross section agrees well with the predictions from the dipolar scattering theory, which follow a universal scaling law depending only on the dipole moment and on the atomic mass. Our approach to quantum degeneracy proceeds with very high cooling efficiency and provides large atomic densities, and it may be extended to various dipolar systems. [more]
ERBIUM NEWS
We have measured and analyzed the hyperfine structure of two lines, one at 583 nm and one at 401 nm, of the only stable fermionic isotope of atomic erbium as well as determined its isotope shift relative to the four most-abundant bosonic isotopes. Our work focuses on the J→J+1 laser cooling transitions from the [Xe]4f126s2(3H6) ground state to two levels of the excited [Xe]4f126s6p configuration, which are of major interest for experiments on quantum degenerate dipolar Fermi gases. From a fit to the observed spectra of the strong optical transition at 401 nm we find that the magnetic dipole and electric quadrupole hyperfine constants for the excited state are Ae/h=−100.1(3)MHz and Be/h=−3079(30)MHz, respectively. The hyperfine spectrum of the narrow transition at 583 nm, was previously observed and accurate Ae and Be coefficients are available. A simulated spectrum based on these coefficients agrees well with our measurements. We have also determined the hyperfine constants using relativistic configuration-interaction ab initio calculations. The agreement between the ab initio and fitted data for the ground state is better than 0.1%, while for the two excited states the agreement is 1% and 11% for the Ae and Be constants, respectively.[more]
ERBIUM NEWS
We report on the experimental realization of a robust and efficient magneto-optical trap for erbium atoms, based on a narrow cooling transition at 583 nm. We observe up to N=2×10^8 atoms at a temperature of about T=15 μK. This simple scheme provides better starting conditions for direct loading of dipole traps as compared to approaches based on the strong cooling transition alone, or on a combination of a strong and a narrow kHz transition. Our results on Er point to a general, simple, and efficient approach to laser cool samples of other lanthanide atoms (Ho, Dy, and Tm) for the production of quantum-degenerate samples.[more]
ERBIUM NEWS
We report on the achievement of Bose-Einstein condensation of erbium atoms and on the observation of magnetic Feshbach resonances at low magnetic fields. By means of evaporative cooling in an optical dipole trap, we produce pure condensates of Er168, containing up to 7×104 atoms. Feshbach spectroscopy reveals an extraordinary rich loss spectrum with six loss resonances already in a narrow magnetic-field range up to 3 G. Finally, we demonstrate the application of a low-field Feshbach resonance to produce a tunable dipolar Bose-Einstein condensate and we observe its characteristic d-wave collapse. [more]
By quenching the contact interaction, it is possible to destroy the phase coherence in a dipolar supersolid. However, the supersolidity is “repaired” when reversing the dephasing process.
In joint theoretical and experimental work with our theory colleagues A.-M. Rey (JILA) and B. Zhu (ITAMP) we investigate dipolar induced magnetization-conserving spin exchange dynamics with fermionic Er in a 3D optical lattice
The ERBIUM lab
In a combined theory and experimental work, we study the elementary excitations of trapped dipolar quantum gases crossing from regular superfluid to supersolid.
We have created for the first time a dipolar quantum mixture by combining two highly magnetic atomic species, Erbium and Dysprosium.
In collaboration with our theory collaborators from Innsbruck and Hannover, we have observed for the first time so-called roton quasiparticles in an ultracold bosonic gas of erbium atoms.
The group, led by Francesca Ferlaino, is located at the Institute for Experimental Physics (IExP) of the University of Innsbruck and at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences.