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Preparing antihydrogen at rest for the free fall in

Preparing antihydrogen at rest for the free fall in. Laurent Hilico Jean-Philippe Karr Albane Douillet Vu Tran Julien Trapateau. Ferdinand Schmidt Kaler Jochen Walz Sebastian Wolf. 2014 – 2017 Bescool project. WAG 13-15 November 2013 Bern. Outline. H + motion control requirements

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Preparing antihydrogen at rest for the free fall in

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  1. Preparing antihydrogen at rest for the free fall in Laurent Hilico Jean-Philippe Karr Albane Douillet Vu Tran Julien Trapateau Ferdinand Schmidt Kaler Jochen Walz Sebastian Wolf 2014 – 2017 Bescool project WAG 13-15 November 2013 Bern

  2. Outline • H+ motion control requirements • Capture and cooling challenges • Experimental progress

  3. GBAR overview

  4. Last GBAR steps H H+ Capture and cooling by laser cooled Be+ ions Threshold Photodetachment l=1.7 µm Reaction chamber H at rest Recoil 0.23 m/s H+ g e+ 1 .. 6 keV Temperature 60 .. 300 eV 30 cm Accurate measurment of g < 1 % H initial velocity Dv0 < 0.8 m/s H+ 3 neV, 20 µK

  5. H with v0 < 1 m/s ? Ground state quantum harmonic oscillator w < 3 MHz m = 1.67 10-27 kg , Dv0 < 0.8 m/s Cooling challenges Cold trappedH+ Reaction chamber Capture + Cooling Trapped particule Temperature 3 neV 20 µK Kinetic energy 1 .. 6 keV Temperature 60 .. 300 eV 700 000 K ÷ 1010..11 Frontiers of Quantum world NIST D. Wineland Innsbruck R. Blatt Classical world

  6. Two Cooling Steps First step Capture and sympathetic Doppler cooling by laser cooled Be+ ions in the linear capture trap (Paul trap, r0 = 3.5 mm, W = 13 MHz) few mm H+ 313 nm laser 300 eV, T = 240 000 K T ÷ 3 109 > 10 000 laser cooled Be+ ions 100 neV, T ~ mK Second step Transfer and ground state cooling of a Be+/H+ ion pair in the precision trap F. Schmidt Kaler, S. Wolf , Mainz

  7. t H+ intake Ubiais=980 V time 0 V Capture efficiency First step Be+ laser cooled ions 1 keV H+ ions Biased linear RF Paul trap Output end-caps Input end-caps 1000… 0 V Versus initial temperature (eV) Versus intake delay t eV

  8. Sympathetic cooling time First step • Numerical simulation 500 Be+ and 20 H+ v t = 0 s Ec= 2 meV 313 nm laser t = 8 ms • Hotter H+ ions and larger ion clouds numerical challenge Work plan : Experimental tests with matter ions H2+ or H+

  9. Second step Precision trap – motional couplings Two coupled oscillators in an external potential x,y • z trapping DC potentials • x,y trapping RF effective potentials • Coulomb interaction coupling z H+ Be+ Newton equations equilibrium positions small oscillations in phase mode out of phase mode normal modes individual ion modes x, y, z 1D 3D T. Hasegawa, Phys. Rev. A 83, 053407 (2011) J. B. Wübbena, S. Amairi, O. Mandel, P.O. Schmidt, Phys. Rev. A 85, 043412 (2012)

  10. b12 z motion x,y motion mlc/msc Second step Precision trap – motional couplings Efficient sympathetic cooling mLC/mSC 1 b1 = 50 % b2 = 50 % mLC/mSC = 9/1 b1 = 99.996 % b2 = 0.872 % ?

  11. Doppler cooling in precision trap >> 20 µK

  12. Raman side band cooling w0-D+dhfs- wi w0-D Stimulated Raman transition Spontaneous Raman transitions H+ Be+ w0 D ~ tens of GHz 2P3/2 F=0, 1, 2, 3 3 laser freq. 2 beams F=1, 2 2P1/2 313.13 nm 2S1/2 n=2 dhfs= 1.25 GHz n=3 n=2 wvibr

  13. Raman side band cooling Second step Stimulated Raman transition no spontaneous emission coherent process Rabi oscillation D Population transfert probability Lamb Dicke parameter For n → n-1, p pulse duration n=2 ~ 10 ms < 1s n=3 n=2

  14. Experimental progress

  15. Capture trap design Jean-Philippe Karr Hot H+ RF 250 V at 13.3 MHz, r0 = 3.5 mm DC’s 2 .. 10 V 313 nm cooling laser Quadrupole guide 12 mm RF DC O V DC

  16. Transfer to precision trap Design: Sebastian Wolf, Mainz Capture trap Photodetachment l = 1.64 µm ~2 mm l = 313 nm Cooling Mainz implantation trap

  17. Vacuum vessel with cryopumping H+ Capture trap Precision trap

  18. Work plan 11/2013 12/2013 2013 Achieve the design Setup the cooling lasers 03/2014 12/2014 2014 Test with H2+ and H+ matter ions from the REMPI source Capture trap implementation Precision trap implementation Test with Be+ and Ca+ ions 06/2015 12/2015 2015 Evaluate sympathetic cooling times numerically & experimentally Transfer of precision trap to Paris, 03/2016 12/2016 2016 Be+ and H2+ transfered in precision trap Be+/H2+ ground state cooling

  19. Tests with a H2+ / H+ REMPI source 303 nm pulsed laser 3-4 mJ H2+ ions Ec = 50 eV dE ~ 10 meV H2 100 % efficiency H2+ ions Ec = 0 eV dE ~ 200 meV P=10-10 mb Injection into the quadrupole guide P=10-6 mb Ion creation P=10-8 mb Ion optics H+ Gbar H2+ metrology project HCI highly charged ions 40Ar13+, P. Indelicato, C. Szabo Synergies

  20. Conclusion • Capture of > 10 eV H+ and Doppler cooling in a linear Paul trap • Transfer to precision trap • Doppler and ground state cooling in precision trap OK OK PhD positions available • ANR BESCOOL • ITN ComiQ

  21. Can we improve the motional couplings ? Idea wcoul Efficient coupling w2 w1 Trapped ions w1 ~ w2 ~ 1.0 MHz wCoul ~ 100 kHz z12eq Coulomb coupling z12eq < 40 µm wz 2 ~ 3 wz1 with m1 = 9, m2 =1 Single well poor couplings wx 2 ~ 9 wx1 Double well structure with very small electrodes ? Possible solution

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