Accurate determination of the scattering length of erbium atoms

Abstract

An accurate knowledge of the scattering length is fundamental in ultracold quantum gas experiments and essential for the characterisation of the system as well as for a meaningful comparison to theoretical models. Here, we perform a careful characterisation of the s-wave scattering length $a_s$ for the four highest-abundance isotopes of erbium, in the magnetic field range from 0G to 5G. We report on cross-dimensional thermalization measurements and apply the Enskog equations of change to numerically simulate the thermalization process and to analytically extract an expression for the so-called number of collisions per re-thermalization (NCPR) to obtain $a_s$ from our experimental data. We benchmark the applied cross-dimensional thermalization technique with the experimentally more demanding lattice modulation spectroscopy and find good agreement for our parameter regime. Our experiments are compatible with a dependence of the NCPR with $a_s$, as theoretically expected in the case of strongly dipolar gases. Surprisingly, we experimentally observe a dependency of the NCPR on the density, which might arise due to deviations from an ideal harmonic trapping configuration. Finally, we apply a model for the dependency of the background scattering length with the isotope mass, allowing to estimate the number of bound states of erbium.

13 pages, 8 figures

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• Many-Body Physics with Ultracold Gases
• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Bose-Einstein Condensation of Erbium
• Quantum-fluctuation-driven crossover from a dilute Bose-Einstein condensate to a macro-droplet in a dipolar quantum fluid
• Transient supersolid properties in an array of dipolar quantum droplets
• Long-lived and transient supersolid behaviors in dipolar quantum gases
• Two-color photoassociation spectroscopy of ytterbium atoms and the precise determinations of s-wave scattering lengths
• Spectroscopy of ultracold atoms by periodic lattice modulations
• Dipolar evaporation of reactive molecules to below the Fermi temperature
• Tuning of dipolar interactions and evaporative cooling in a three-dimensional molecular quantum gas
• Dipolar Bose-Einstein condensates with dipole-dependent scattering length
• Feshbach Resonances in an Erbium-Dysprosium Dipolar Mixture
• Controlling interactions between highly-magnetic atoms with Feshbach resonances
• Anisotropic expansion of a thermal dipolar Bose gas
• Anisotropic relaxation dynamics in a dipolar Fermi gas driven out of equilibrium
• Properties of strongly dipolar Bose gases beyond the Born approximation
• Anisotropic thermalization of dilute dipolar gases
• Nonequilibrium dynamics of an ultracold dipolar gas
• Linear Response of a Periodically Driven Thermal Dipolar Gas

Cited by in corpus (19)

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• Observation of vortices and vortex stripes in a dipolar Bose-Einstein condensate
• Microwave shielding of bosonic NaRb molecules
• Bose-Einstein Condensation of Europium
• Strongly dipolar gases in a one-dimensional lattice: Bloch oscillations and matter-wave localization
• Production and stabilization of a spin mixture of ultracold dipolar Bose gases
• Thermoviscous Hydrodynamics in Non-Degenerate Dipolar Bose Gases
• Characterisation of three-body loss in ${}^{166}$Er and optimised production of large Bose-Einstein condensates
• Exploring the Berezinskii-Kosterlitz-Thouless Transition in a Two-dimensional Dipolar Bose Gas
• Thermal Conductivity of an Ultracold Paramagnetic Bose Gas
• Anisotropic acoustics in dipolar Fermi gases
• Broken-axisymmetry state and magnetic state diagram of spin-1 condensate through the prism of quadrupole degrees of freedom
• Competing order in two-band Bose-Hubbard chains with extended-range interactions
• Spin--spin interaction and magnetic Feshbach resonances in collisions of high-spin atoms with closed-shell atoms
• Analytical solutions of the Schrödinger equation for two confined atoms with van der Waals interaction
• Zero sound in a quantum gas of spin-3/2 atoms with multipole exchange interaction
• Universal Efimov spectra and fermionic doublets in highly mass-imbalanced cold-atom mixtures with van der Waals and dipole interactions
• General collisionless kinetic approach to studying excitations in arbitrary-spin quantum atomic gases
• Single impurity atom embedded in a dipolar two-soliton molecule as a qubit