1. Cold atoms near surfaces beyond disorder Della Pietra Leonardo Physikalisches Institut der Universität Heidelberg Philosophenweg 12, 69120 Heidelberg, Germany dpietra@physi.uni-heidelberg.de www.atomchip.org Heidelberg 05.03.05

2. Overview (1) The setup (2) Micromachining the chip: Cleaning wires E wells Playing with I (3) Next chip (4) Plans

3. (1) The chamber 6''Loading 0.3''Evaporation on chip 10 5 atoms BEC Quadrupole MOT->U-MOT Lower chamber: Fast loading (~1'') Upper chamber: Good vacuum 20''RF evaporation Optical pumping Cu-Z magnetic trap ~10 8 atoms

4. (1) The chamber 6''Loading 0.3''Evaporation on chip 10 5 atoms BEC Quadrupole MOT->U-MOT Lower chamber: Fast loading (~1'') Upper chamber: Good vacuum 20''RF evaporation Optical pumping Cu-Z magnetic trap ~10 8 atoms

5. (1) The chamber 6''Loading 0.3''Evaporation on chip 10 5 atoms BEC Quadrupole MOT->U-MOT Lower chamber: Fast loading (~1'') Upper chamber: Good vacuum 20''RF evaporation Optical pumping Cu-Z magnetic trap ~10 8 atoms

6. (1) The chamber 6''Loading 0.3''Evaporation on chip 10 5 atoms BEC Quadrupole MOT->U-MOT Lower chamber: Fast loading (~1'') Upper chamber: Good vacuum 20''RF evaporation Optical pumping Cu-Z magnetic trap ~10 8 atoms

7. (1) The chip gold layer:2.3 µm thin wires:10 µm Structures:~1 µm A B C Imaging: parallel to chip Schneider et al, PRA 67,023612(2003)

8. (2) The FIB Henri J. Lezec ISIS Universite' Louis Pasteur Strasbourg (FR) Small structures: ~20 nm

9. (2) Polishing wires A clean Focused Ion Beam can be used to redefine wire boundaries Lateral wire definition = grain size ( 100 - 30 nm )

10. (2) Polishing wires A clean Focused Ion Beam can be used to redefine wire boundaries Lateral wire definition = grain size ( 100 - 30 nm )

11. (2) Polishing wires Approaching chip: BEC forms in potential well

12. (2) Polishing wires Approaching chip: BEC forms in potential well Last results: Thermal cloud down to the chip

13. (2) E fields U(r) = g F m F µ B B(r) – ½  E(r) 2 Electrostatic interaction does not depend on m F always attractive Typical orders of magnitude ( 7 Li) ● U B [µK] ~ 67 B [G] ● U E [µK] ~ 98 E 2 [V/µm] Already realized with 7 Li : ● Traps ● Motors ● Splitters Folman et al, Adv.At.Mol.Opt.Phys 48, 263 (2002) Krüger et al, PRL (2003)

14. (2) Sharpening E Sharp structures II V Sharp E fields II V µm scale U definition

15. (2) Sharpening E Sharp structures II V Sharp E fields II V µm scale U definition

16. (2) 1,2,...n wells - Playing with potentials Magnetic guide keeps atoms in place; then:

17. (2) 1,2,...n wells - Playing with potentials Magnetic guide keeps atoms in place; then:

18. (2) 1,2,...n wells - Playing with potentials Magnetic guide keeps atoms in place; then: - Playing with positions

19. (2) Disturbing I Notches: 200 x 700 nm I deviates from regular flow => Corrugation in U(B)

20. (2) Q transmission T dependent on Kinetic energy

21. (2) Q transmission T dependent on Kinetic energy Potential depth/width dependent on distance from chip Distance between resonance peaks changes with distance from chip

22. (3) Gold grains A.Bietsch B.Michel Appl.Phys.Lett. 80, 3346 (2002) C.Durkan M.E.Welland PRB 61,14215 (2000) Times 22 Contact resistance between wire and wire up to 10 Ohm Dependent on relative crystal orientations

23. (3) Next Chip Wires:Thin/Thick Narrow/Wide Transversal/Longitudinal confinement: independent NEW SAMPLES

24. (3) Gold grains II 1x1µm 750nm 25°C 1x1µm 250nm 300°C Grain size << Thickness Grain size ~ Thickness NEW SAMPLES 1x1µm 250nm 25°C

25. (4) Plans ● Microscopic field sensing ● Holography ● Interferometry ● Magnetic traps + optical grids

26. (4) The Group Review: R.Folman, P.Krüger, J. Schmiedmayer, J.Denschlag, C.Henkel, Adv. At. Mol. Opt. Phys. 48, 263 (2002) Jörg Schmiedmayer Rb team: Leonardo Della PietraSimon Aigner Chips: Ron Folman Sönke Groth http://www.atomchip.org