Magnetically tunable Feshbach resonances in ultracold gases of europium atoms and mixtures of europium and alkali-metal atoms

Abstract

We investigate magnetically tunable Feshbach resonances between ultracold europium atoms and between europium and alkali-metal atoms using multichannel quantum scattering calculations. For ultracold gases of europium atoms both homonuclear 153 Eu+ 153 Eu and heteronuclear 151 Eu+ 153 Eu systems are studied. Calculations for mixtures of europium and alkali-metal atoms are carried out for prototype systems of 153 Eu+ 87 Rb and 153 Eu+ 7 Li. We analyze the prospects for the control of scattering properties, observation of quantum chaotic behavior, and magnetoassociation into ultracold polar and paramagnetic molecules. We show that favorable resonances can be expected at experimentally feasible magnetic-field strengths below 1000 G for all investigated atomic combinations. For Eu atoms, a rich spectrum of resonances is expected as a result of the competition between relatively weak short-range spin-exchange and strong long-range magnetic dipole-dipole interactions, where the dipolar interaction induces measurable resonances. A high density of resonances is expected at magnetic-field strengths below 200 G without pronounced quantum chaos signatures. The present results may be useful for the realization and application of dipolar atomic and molecular quantum gases based on europium atoms in many-body physics.

Quantum chaos in Feshbach resonances of the ErYb system

“…Since then, the chaotic character of bound states and Feshbach resonances in ultracold collisions was also found for several other systems, for example, in mixtures of Yb atoms in 1 S 0 and 3 P 2 states at large magnetic fields [28], and molecular collisions of Li atom with CaH and CaF [29]. On the other hand, the resonance spacings in collisions of Er and Li atoms in a magnetic field [30], and of highly magnetic europium ( 7 S) with alkali metal atoms [31] have both been shown to follow the non-chaotic poissonian distribution.Here we investigate the interactions and Feshbach spectra between weakly anisotropic lanthanides and heavy spin-singlet atoms using ErYb as a prime example. Ytterbium, alongside Sr, is the most widely used spin-singlet atom with applications for optical clocks, quantum gases and quantum simulation [32][33][34][35].…”

Narrow-line magneto-optical trap for europium

“…This enables us to control their scattering length using radiofrequency fields [7,8]: such control is useful for examining the behavior of dipolar spinor Bose gases under an ultralow magnetic field [9][10][11]. Since the electronic angular momentum of the ground state is zero, a less dense and nonchaotic Feshbach resonance spectrum is expected in the case of Eu, which is in contrast to the spectra of other dipolar lanthanides [12][13][14].…”

Prospects of Forming High-Spin Polar Molecules from Ultracold Atoms

“…Such molecules are analogous to symmetric tops; they will allow the simulation of important problems in quantum magnetism [43,44] and may also open up new opportunities for scalable quantum computers [45]. These advantages are not offered by molecules formed from pairs of atoms in S states, even if they have high spin [46], since there is no Ω doubling for Σ states.…”