Interference of Two Molecular Bose-Einstein Condensates

1. Interference of Two Molecular Bose-Einstein Condensates Christoph Kohstall Innsbruck FerMix, June 2009

2. Fer(Mix)-Team Johannes Hecker Denschlag Christoph Kohstall Rudi Grimm Leonid Sidorenkov Edmundo Sánchez Guajardo Stefan Riedl

3. Analysing different system sizes, we observe the crossover from thermal to quantum noise, reflected in a characteristic change in the distribution functions from poissonian to Gumbel type, in excellent agreement with theoretical predictions on the basis of the Luttinger-liquid formalism. We present the first experimental observation of quasi-long-range order in one-dimensional atomic condensates, • Interference of atomic Bose condensates • A powerful tool to study Bose gases • Interference meets Fermi gases • Interesting challenges Fermions form bosonic pairs strong interaction

4. Analysing different system sizes, we observe the crossover from thermal to quantum noise, reflected in a characteristic change in the distribution functions from poissonian to Gumbel type, in excellent agreement with theoretical predictions on the basis of the Luttinger-liquid formalism. We present the first experimental observation of quasi-long-range order in one-dimensional atomic condensates, • Interference of atomic Bose condensates… • a powerful tool to study Bose gases • Now interference meets Fermi gases • highlights and • interesting challenges from atoms to molecules bosonic pairs of fermions strong interaction

5. BEC BCS molecules many-body pairs Fermionic lithium – our workhorse Let‘s open the door!

6. TOF-Images TOF=0.4 ms B = 700 G visibility ~25% 4 ms 8 ms 12 ms 14 ms x z 80 pixel 250 µm 0 z phase visibility fringe spacing

7. coils for mag. Feshbach field trapping beam beam waist 54 µm ωy 2π*20Hz ωx , ωz 2π*150Hz mag. field 700 G N↑,↓ 200 000 1/kFa 3 separation 64 µm lens Li create split overlap observe CCD AOM z x split create overlap observe z Procedure y x confinement z y x

8. Expansion coils for mag. Feshbach field trapping beam beam waist 54 µm ωy 2π*20Hz ωx , ωz 2π*150Hz mag. field 700 G N↑,↓ 200 000 1/kFa 3 separation 64 µm lens Li CCD AOM no slicing necessary in situ TOF=0 ms in expansion TOF = 14 ms magnifying glass clouds clouds 4 ms position position position position trap trap trap trap

9. Relative phase potential clouds phase Same result for independent BECs

10. Temperature dependence TC bars are rms ~0.5TF=TC

11. Interaction strength

12. Interaction strength

13. Interaction strength

14. potential pairing lifetime collisions detection 7% 17% 34% not valid 0.1 1 30 Depleted part has no common phase partial reflection Ekin<Emf Ekin>Epairing no survival We gotta be creative ! short lifetime of molecules interactions limit no pairs in expansion

16. potential pairing lifetime collisions detection 7% 17% 34% not valid 0.1 1 30 partial reflection Ekin<Emf Ekin>Epairing no survival We gotta be creative ! short lifetime of molecules interactions limit no pairs in expansion

17. Interference of molecular BECs The challenge of strong interaction Tool for new physics