Heidelberg 2015 – scientific programme

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MO: Fachverband Molekülphysik

MO 17: Cold Molecules 3

MO 17.7: Talk

Thursday, March 26, 2015, 12:45–13:00, PH/HS1

Precise study of deep two-body subradiance with ultracold Sr₂ molecules — •Wojciech Skomorowski^1,3, Bart McGuyer², Mickey McDonald², Geoffrey Iwata², Marco Tarallo², Robert Moszynski³, and Tanya Zelevinsky² — ¹Theoretische Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany — ²Department of Physics, Columbia University, 538 West 120th Street, New York, NY 10027-5255, USA — ³Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland

Weakly bound molecules have physical properties without atomic analogues, even as the bond length approaches dissociation. For instance, the internal symmetries of homonuclear diatomic molecules result in the formation of two-body superradiant and subradiant excited states. While superradiance has been demonstrated in a variety of systems, subradiance is more elusive due to the inherently weak interaction with the environment. Here we directly probe deeply subradiant states in ultracold diatomic strontium molecules near the intercombination atomic line, and characterize their properties by ab initio model [1]. We find that two competing effects limit the lifetimes of the subradiant molecules, with different asymptotic behaviors. The first is radiative decay via magnetic-dipole and electric-quadrupole interactions. We prove that its rate grows quadratically with the bond length, confirming quantum mechanical predictions. The second is nonradiative decay through weak non-adiabatic predissociation, with a rate proportional to the vibrational spacing and sensitive to short-range physics.

[1] B. H. McGuyer et al., Nat. Phys. (2015), doi:10.1038/nphys3182.