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H 2 CO

QED. e-. e-. e-. e-. HCO. OH. H 2 O. H 2 CO. Cold and Ultracold Molecules. J. Ye, JILA, NIST & CU. http://jilawww.colorado.edu/ Ye Labs. EuroQUAM, Durham, April 18, 2009. Quantum dipolar gas. Precision test. Quantum measurement. Chemical reactions. Why ultracold matter?.

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H 2 CO

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  1. QED e- e- e- e- HCO OH H2O H2CO Cold and Ultracold Molecules J. Ye, JILA, NIST & CU http://jilawww.colorado.edu/YeLabs EuroQUAM, Durham, April 18, 2009 Quantum dipolar gas Precision test Quantum measurement Chemical reactions

  2. Why ultracold matter? • We can understand it • We can control it • The most precise measurements ever ! • Quantum control, Quantum simulations, Quantum information • Fundamental understandings in condensed matter

  3. + + R _ _ Dipolar quantum systems Atoms Polar molecules Magnetic dipoles Electric dipoles R d ~ Bohr magneton d ~ Debye e.g. BEC of Crd=6mB (T. Pfau, Stuttgart) EI~10 - 1000 nK @ n=1012-1014/cm3 EI~10-3 - 10-1 nK @ n=1012-1014/cm3

  4. Science with cold molecules High density, Ultracold temperature Dipolar crystal Phase transition & many-body Dipolar quantum gas Quantum information Ultracold Chemistry ~ KBT Molecule optics & circuitry Cold controlled chemistry 12 9 log10(density [cm-3]) Novel collisions Fundamental tests Precision measurement 6 3 0 -9 -6 -3 log10(temperature [K])

  5. Quantum degeneracy Coherent state transfer Enhanced PA? Laser cooling? Sympathetic cooling? Evaporative cooling? Technology for cold molecules Carr, DeMille, Krems, & Ye, New. J. Phys. Special Issue (2009). 12 9 Buffer-gas cooling log10(density [cm-3]) Stark, magnetic, optical deceleration 6 Photo-association 3 -9 -6 -3 0 log10(temperature [K])

  6. Ultracold molecules: Precision Chemistry Electric field OH HCO H2CO H2O E. Hudson et al., Phys. Rev. A 73, 063404 (2006). Controlled molecular collisions Ultracold chemical reactions Stereo-Chemistry • Molecules in single quantum states, under precise control, for internal & external motions • Unprecedented study of fundamentally important reactions (Dial the rates): OH + HBr, OH + H2CO, CN + O2, OH + NO, OH + OH, CN + NH3, OH + H

  7. OH H2CO 550 m/s to rest 1 K to 10 mK 104 – 106 molecules Density: 105 – 107 /cm3 Dv f0 = 00 400 f 200 300 800 Cold ground-state molecules - Stark slower Bethlem, Berden, Meijer, Phys. Rev. Lett. 83 1558 (1999). Bochinski et al, Phys. Rev. Lett. 91, 243001 (2003). 370 m/s 336 m/s 300 m/s 259 m/s 211 m/s 33 m/s 148 m/s

  8. d s O H Magnetic trapping of OH Sawyer et al., Phys. Rev. Lett. 98, 253002 (2007). decelerator Magnetic trap

  9. 10mm Permanent-Magnet Trap NdFeB (N42SH) Top= 120oC Bres = 1.24 T

  10. Trap Loading 0 V +12 kV -12 kV

  11. Trap Loading ~ 2 x 106 cm-3 70 mK 0 V 0 V 0 V

  12. Trap and collisions Sawyer et al., Phys. Rev. Lett. 101, 203203 (2008). OH • Quantum threshold collisions • Resonant energy transfer Ecm ~ 5 cm-1 – 230 cm-1 He, D2, NH3 , … beam source

  13. 2P3/2 OH J = 5/2 84 cm-1 J = 3/2 Ecm (cm-1) Absolute collision cross sections D2: (1) J = 1 quadrupole moment (2) J = 1  J =3 (300 cm-1)

  14. H H/D H/D OH Magnet trap H/D Ecm < 5 cm-1 Electric Quadrupole guide: 13.5 cm ROC +/- 5 kV ~130 m/s ND3 N O Buffer gas-cooled molecule source The possibility to probe polar collisions? Doyle, Rempe, …

  15. (c) (b) (a) (d) A Molecular MOT ? B. K. Stuhl et al., “A magneto-optical trap for polar molecules,” Phys. Rev. Lett. 101, 243002 (2008). TiO

  16. Polar molecules near quantum degeneracy S. Ospelkaus, K.-K. Ni, M. Miranda, B. Neyenhuis, D. Wang, S. Kotochigova, P. S. Julienne, D. Jin, and J. Ye J. Bohn (JILA), J. Hutson (Durham) 87Rb Bosons 40K Fermions • Temperature ~400nK • T/TF=3 • Density ~1012/cm3 • r=0.01 • Dipole ~0.5 Debye • Long lived (~200ms) KRb molecules

  17. Traditional photo-association Pillet Stwalley Heinzen Bigelow … … |Ye(R)|2 Energy Laser |Yf(R)|2 |Yg(R)|2 EK Internuclear distance R

  18. Resonant enhancement DeMille Weidemüller |Ye(R)|2 Laser Energy |Yf(R)|2 |Yg(R)|2 EK Internuclear distance R

  19. Resonant enhancement – in the ground |Ye(R)|2 Côte Energy Laser |YFR(R)|2 EK Internuclear distance R

  20. Magnetic-field Feshbach resonance Energy V(R) R R R R Colliding atoms Magnetic field > B Ebinding molecules Zirbel et al., Phys. Rev. Lett. 100, 143201 (2008). Field-tunable scattering resonance

  21. Excited electronic state Dump Pump Going to really deep ground potential The problem – overlap Laser fields: 1. Impractically strong 2. Nonlinear excitations Ground Electronic state

  22. Excited electronic state Dump Pump Dump pulse Pump pulse Coherent weak fields to achieve strong field effect Pe’er, Shapiro, Stowe, Shapiro, Ye, Phys. Rev. Lett. 98, 113004 (2007). Ground Electronic state Wave-packet dynamics bridge the overlap mismatch Coherent accumulations resolve single quantum state

  23. Frequency comb assisted STIRAP Sr2 n w1 w2 Feshbach + STIRAP Ospelkaus et al., Nature Phys. 4, 622 (2008) Ni et al., Science 322, 231 (2008) 1P Good Franck-Condon for both up and down transitions. Excited state is triplet + singlet mixture Energy 3S w1 w2 3S 1S v = 0, N = 0, J = 0 Inter-nuclear distance R

  24. Counting the light ripple JILA Sr optical atomic clocks Ludlow et al., Science 319, 1805 (2008). Campbell et al., Science 324, 360 (2009). Inaccuracy ~ 1 x 10-16 (uncertainty in SI unit of time: 4 x 10-16)

  25. W1fixed,W2 scanned Raman + EIT Dark Resonance W1scanned, W2 fixed

  26. Stark Spectroscopy B=1.1139(1) GHz d=0.566(17) Debye Stark Shift (MHz)

  27. Coherent Transfer - STIRAP 4μs one-way transfer 92% efficiency No heating T/TF=2.5

  28. 0 ms 1 ms 3 ms 6 ms No Heating in Transfer Process Direct Imaging of Molecules

  29. Trapped Ground state polar molecules Ospelkaus et al., Faraday Discussions 142 Lifetime ~ 150 ms Trap oscillation E Pol

  30. 3x104 K, t=70(10)ms 3x105 K, t=6(1)ms Atom-molecule collisions KRb+ K

  31. Atom-molecule collisions KRb+ K KRb+Rb b=5.4(1.0) 10-11 cm3/s b=6.5(1.0) 10-11 cm3/s

  32. A harpoon mechanism? J. Bohn D. Herschbach J. Hutson P. Julienne ionization energy - electron affinity (1) Near unity probability loss due to short-range reactions (2) Quantum threshold behavior - long-range potential (van der Waals “Length”) characterizes universal inelastic scattering Upper bound: 11 x10-11 cm3/s (KRb + K); 7.9 x10-11 cm3/s (KRb + Rb)

  33. Atom-molecule collisions exothermic KRb+ K -> K2+Rb+ Rb2 KRb endothermic KRb+ Rb -> Rb2+K- K2

  34. Nuclear spin states for v = 0, N = 0 J. Aldegunde J. Hutson We populate a single nuclear spin state

  35. U(R) (nK) J. Bohn Dipolar collision resonance? Collisions of two ground-state Fermionic polar molecules Evaporative cooling?Control of elastic/inelastic collisions? Shape or Feshbach? We will know soon.

  36. Ultracold molecules: quantum physics • Quantum information • (strong dipolar interactions, long coherence time) • Quantum degeneracy (e.g. BEC) • (anisotropic interactions) • Dipolar phase transition • (Condensed matter system) DeMille, Phys. Rev. Lett. 88, 067901 (2002). H.P. Buchler et al., PRL 98, 060404 (2007). T. Koch et al., Nature Phys. 4, 218 (2008). Micheli, Brennen, Zoller, Nature Physics 2, 341 (2006).

  37. Special thanks OH and H2CO B. Sawyer B. Stuhl M. Yeo E. Hudson (UCLA) B. Lev (Illinois UC) H. Lewandowski (JILA) J. Bochinski (NC State) KRb S. Ospelkaus K.-K. Ni M. Miranda B. Neyenhuis D. Wang A. Pe’er (Israel) J. Zirbel Deborah Jin J. Bohn (JILA) P. Julienne (NIST), S. Kotochigova (Temple), J. Hutson (Durham)

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