Experiments

Quantum degenerate dipolar gas of dysprosium atoms

Long-range interactions, such as Coulomb interaction between electrons and dipolar interaction between magnetic spins, usually govern the behavior of many physical systems. A controlled experimental environment to study quantum effects of long-range interactions is therefore of general interest. Ultracold polar molecules, frozen Rydberg atoms and quantum gases with strong magnetic dipolar interactions offer the possibility to study paradigm systems that can lead to better understanding some physical mechanisms of real matter and possibly to the engineering of new materials. Moreover, the ability to hold them in the ordered environment provided by an optical lattice opens the way to studies of strongly-correlated systems in different dimensionalities.
With the present project we use a quantum gas of dysprosium atoms to perform quantum simulations of strongly-correlated dipolar systems. Contrary to alkali atoms, usually employed in cold atoms experiments, dysprosium has a huge magnetic dipole moment, 10 Bohr magnetons, the largest among all elements. For this reason, besides interacting via van der Waals interaction, which has substantially a contact nature, Dy atoms also interact via dipole-dipole magnetic interaction, which is both long-range and anisotropic. The combination of these two ingredients leads to the appearance of peculiar quantum phenomena so far only barely explored[1-3]. Moreover, Dy isotopes, with both fermionic and bosonic nature, can be brought to quantum degeneracy[2,3], allowing statistics-dependent studies.

In July 2016 a magneto-optical trapping (MOT) of 162Dy has been observed and characterized in ref.[4]. In November 2017 the first Bose-Einstein Condensate (BEC) of 162Dy has bee realized. In the first experiments we have studied the scattering properties of Dy BEC [5]. We are currently studying the rotonic instability induced in the dipolar condensate.

This experiment is a joint effort of teams from the Pisa section of CNR-INO and the LENS (University of Florence and CNR-INO Sesto F.).

References
[1] C. Trefzger, C. Menotti, B. Capogrosso-Sansone, and M Lewenstein, Ultracold dipolar gases in optical lattices, J. Phys. B: At. Mol. Opt. Phys. 44 (2011) 193001.
[2] Mingwu Lu, Nathaniel Q. Burdick, Seo Ho Youn, and Benjamin L. Lev, Strongly Dipolar Bose-Einstein Condensate of Dysprosium, Phys. Rev. Lett. 107 (2011) 190401
[3] Mingwu Lu, Nathaniel Q. Burdick, and Benjamin L. Lev, Quantum Degenerate Dipolar Fermi Gas, Phys. Rev. Lett. 108 (2012) 215301
[4] E. Lucioni, G. Masella, A. Fregosi, C. Gabbanini, S. Gozzini, A. Fioretti, L. Del Bino, J. Catani, G. Modugno, M. Inguscio, A new setup for experiments with ultracold dysprosium atoms, Eur. Phys. J. Sp. T. 226, 2775–2780 (2017)
[5] Lucioni E., Tanzi L., Fregosi A., Catani J., Gozzini S., Inguscio M., Fioretti A., Gabbanini C., Modugno G, Dysprosium dipolar Bose-Einstein condensate with broad Feshbach resonances, PHYSICAL REVIEW A Vol.97 (6) pag.060701-1-060701-5 (2018).

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