Goulven Quéméner

Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, Bat. 505, Campus d’Orsay, 91405, ORSAY

e-mail: goulven.quemener@u-psud.fr

Ultracold molecular dipolar gases often suffer from losses due to chemical reactions [1, 2] or eventual sticky collisions for non-reactive molecules [3]. Loss suppression for both bosonic and fermionic dipolar species can be obtained in an electric field in a one-dimensional optical lattice [4] but this requires usually strong confinements to get into a pure two-dimensional collision regime. An alternative way can be found without confinement using rotationally excited molecules. In this talk, I will explore the ultracold collisions of rotationally excited dipolar molecules in free space. I will focus on electric dipolar molecules of KRb [5] and electric and magnetic dipolar molecules of RbSr, SrF, BaF and YO [6]. I will show that one can sharply tune the elastic, inelastic and reactive rate coefficients of lossy molecular collisions when a second rotationally excited colliding channel crosses the threshold of the initial colliding channel, with the help of an applied electric field. We can increase or decrease the loss processes whether the second channel is above or below the initial channel and suppress loss collisions. This could lead to favorable conditions for evaporative cooling.

[1] Ospelkaus, Ni, Wang, de Miranda, Neyenhuis, Quéméner, Julienne, Bohn, Jin, Ye, Science 327, 853 (2010)

[2] Ni, Ospelkaus, Wang, Quéméner, Neyenhuis, de Miranda, Bohn, Jin, Ye, Nature 464, 1324 (2010)

[3] Mayle, Quéméner, Ruzic, Bohn, Phys. Rev. A 87, 012709 (2013)

[4] de Miranda, Chotia, Neyenhuis, Wang, Quéméner, Ospelkaus, Bohn, Ye, Jin, Nature Physics 7, 502 (2011)

[5] G. Wang, G. Quéméner, New J. Phys. 17, 035015 (2015)

[6] G. Quéméner, J. L. Bohn, Phys. Rev. A 93, 012704 (2016)