Quadrupolar atoms and molecules as a new platform to study many-body physics

The ongoing quest on achieving high-density samples of dipolar atoms and molecules aims at observing the exciting many-body phenomena predicted in such systems [1].

In the recent article in Physical Review Letters [2], the authors from ITAMP, George Mason University, and the University of Hamburg, introduced an alternative platform for quantum simulation of many-body systems. The proposed setup is based on nonspherical atoms or molecules with zero dipole moments but possessing a significant value of electric quadrupole moments.

Considering a quadrupolar Fermi gas trapped in a 2D square optical lattice, the authors showed that the peculiar symmetry and broad tunability of the quadrupole-quadrupole interaction results in a rich phase diagram encompassing unconventional BCS and charge density wave phases, and opens up a perspective to create a topological superfluid.

Quadrupolar species, such as metastable alkaline-earth atoms and homonuclear molecules, are stable against chemical reactions and collapse and are readily available in experiment at higher densities compared to the dipolar atoms and molecules.

[1] T. Lahaye et al., Rep. Prog. Phys. 72, 126401 (2009); M. Baranov, Phys. Rep. 464, 71 (2008)

[2] S. G. Bhongale, L. Mathey, E. Zhao, S. F. Yelin, M. Lemeshko, Phys. Rev. Lett. 110, 155301 (2013)