What do you care what molecules are?...© Olivier DULIEU Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, Orsay,France © Inspired by R.P. Feynman, « What do you care what other people think? » (1988) Interferences and Quantum Aplications French-German University EUROQUAM Satellite Meeting on Cold and Ultracold Molecules Durham, April 17-18,

The Cold Molecule Theory group in Orsay Mireille Aymar Nadia Bouloufa Anne Crubellier O.D. Eliane Luc Maurice Raoult Jacques Robert Viatcheslav Kokoouline (from U. Central Florida) Romain Guérout Mehdi Ayouz Romain Vexiau Johannes Deiglmayr (Freiburg) Andres Gerdes (Hannover) Rachidi Osséni EUROQUAM coll’s: J. Danzl, J. Denschlag, H.-C. Nägerl,…(Innsbruck) A.Grochola, M. Weidemüller, R. Wester,…(Freiburg) P. Soldan (Prague) E. Tiemann (Hannover) C. Gabbanini (Pisa) (Review: « Formation and interactions of cold and ultracold molecules: new challenges for interdisciplinary physics », to appear in Reports on Progress in Physics-2009)

Summary, Outline, Aim, Purpose « The field of cold and ultracold molecules has recently witnessed a number of spectacular advances reliant upon the high quality of our knowledge of molecular structure at a very fundamental level. This talk will illustrate this premise in the context of the current meeting, highlighting the characteristics of molecules that we all care about. »* * Special thanks to S. Cornish Phase space density binding energy (Hz) X(0,0) molecules Q U A N T. D E G E N. Atomic properties Molecular structure, spectroscopy Molecular structure, spectroscopy Molecular dynamics Cold Chemistry

Degree of universality, common trends? Asympotic theories for long-range interactions, MQDT, … Threshold laws,… … As theoreticians, do we have to systematically compute all details of all molecular properties, especially in the prespective of forthcoming experiments? A few trends from the Faraday discussions this week:  Ultracold alkali atoms may not be an appropriate coolant for open- shell molecules…  Ultracold alkaline-earth atoms could be more favorable…  Ultracold metastable rare gas atoms, quenched to their ground state, look promising… But the final answer is probably… …that we have to solve the N-body problem, whose solution crucially depends on N

Trends from the « alkali age » (not yet fossils!) Pure long-range molecules 0g-0g- X 0u+0u+ 6s+6p 3/2 6s+6p 1/2 « THE » A~b coupled system Energy (cm -1 ) R (a.u.) 6s+6s Typical REMPI scheme for ultracold molecule detection

R (a.u.) Dipole moment (Debye) Permanent dipole moments X1+X1+ LiCs KRb Aymar&Dulieu, JCP, 122, (2005) Park et al (2000) X1+X1+ a3+a3+ Kotochigova et al 2004) This work Kotochigova et al, PRA 68, (2003) Park et al, Chem. Phys, 257, 135 (2000) KRb Measured by Ni et al (2008)

Static dipole polarizabilities for alkali pairs: parallel perpendicular SCALING LAW with the cube of the equilibrium distance Deiglmayr et al, JCP 2008

Average polarizability Anisotropy Static dipole polarizabilities for alkali pairs: dependence with vibrational level

Dynamic polarizabilities of Cs 2 (X, v=0, J=0)

In the long-range of alkali dimers… Na 2 Adapted from Jones et al,RMP 2006, Weiner et al, RMP 1999 Observation of Pure Long- range Molecules Predicted by Uang et al, PRL 1978 Hyperfine structure Fine structure Aldegunde et al arXiv: v1 Rb 2, v=0

And here comes the full landscape… 0 u + (P 1/2 ) a3u+a3u+ X1g+X1g+ 0 u + (P 3/2 ) 6s 1/2 +6s 1/2 A1u+A1u+ b3ub3u 6s 1/2 +6p 1/2 6s 1/2 +6p 3/2 A few examples of « non-universality…

Mechanism for the formation of low-v ground state molecules in Cs 2 : « resonant coupling » 4-state coupling 2-step decay v=1-7 Viteau et al, Science 2008, PRA 2009

New PA lines Bv= cm -1 Re  8.73a 0 J=5-14!

0u+0u+ 3g+3g+ 10 lines in the range 1118 to 1135 nm, two progressions Challenge:assignment relying on 10 lines, for the prediction of the best possible STIRAP paths V = 150 X 0u+0u+ 3  g + (0 g -,1g) Energy (cm -1 ) 1130 nm # 222 In the course of STIRAP on Cs 2 in Innsbruck One-photon spectroscopy Danzl et al, Science 2008, and FD142,

0 u + (P 1/2 ) (A 1  u + ) 0 u + (P 1/2 ) (b 3  u ) SO coupling 6s 1/2 +6p 1/2 6s 1/2 +6p 3/2 A1u+A1u+ b3ub3u 0 u + (P 3/2 ) Level #20 Level # 221 R-dependent SO coupling Modelling the intermediate states: „resonant coupling“ 3u3u 1u+1u+ level # 20 level # 222 ~222 ~20

Observation of PA at short-range into excited levels of LiCs (B 1  ) in Freiburg Deiglmayr et al, PRL 2008, NJP, to appear (2009)

Radial wave functions in LiCs

PA in LiCs B 1  u (v=1) Pure singlet hf-mixed

Broad Feshbach resonance

Resonant coupling: an even more general mechanism for cold molecule manipulation Ospelkaus et al, FD142/19 KRb Lisdat et al, EPJD 2001 K2K2

What’s next ?...are alkali trimers a « collection of three alkali pairs »? Soldan&Hutson, PRA 2003 V trimer V pairs

Full calculations for Cs 3 (R. Guérout, Poster P7 at FD142)

Thank you!