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Experimental Atomic Physics Research in the Budker Group

Experimental Atomic Physics Research in the Budker Group. Tests of fundamental symmetries using atomic physics: Parity Time-reversal invariance Permutation Postulate/Spin-Statistics Connection Temporal variation of fundamental “constants” Applied atomic spectroscopy

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Experimental Atomic Physics Research in the Budker Group

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  1. Experimental Atomic Physics Research in the Budker Group • Tests of fundamental symmetries using atomic physics: • Parity • Time-reversal invariance • Permutation Postulate/Spin-Statistics Connection • Temporal variation of fundamental “constants” • Applied atomic spectroscopy • Sensitive magnetometry and electrometry • Nonlinear optics with atoms • Optical properties of superfluid helium • “New” atomic energy levels • Properties of complex atoms: the rare earths, Ba

  2. Group Demographics and Philosophy • 6 graduate students • 1 - 3 undergrads • 2 staff scientists (1 senior, 1 junior) • Part-time technician • Lots of visitors from US and abroad • Each student has their own project • Lots of interactions within group • Variety of experiences and techniques: lasers, optics, atomic beams and vapor cells, cryogenics, computer control and data acquisition, vacuum, electronics, theory, scientific writing and editing, …..

  3. Further information: http://socrates.berkeley.edu/~budker budker@socrates.berkeley.edu Office: 273 Birge; labs: 217,219,221,230,241, and 245 Birge

  4. Atomic Parity Nonconservation e g e Z Electromagnetic interaction (conserves parity) Weak interaction (violates parity)  Small Modifications of the Optical Properties of Atoms Provides Unique Low-Energy Test of the Standard Model

  5. PNC Experiments Photo-multiplier tubes Oven Collimator Light guide Ytterbium atoms PBC mirror Parabolic 408-nm light y reflector e Electric field plates 649-nm light x E Magnetic field coils B z Electric and magnetic fields define a handedness PNC effects show up as dependence of atom-photon interaction on handedness Two Experiments in Progress:Dysprosium(Z=66) andYtterbium(Z=70)

  6. THEORETICAL Theories that unify gravity with other forces either allow or necessitate a variation EXPERIMENTAL Geophysical: Oklo natural nuclear reactor 1.8 billion years ago: |a/a| < 10-18 /yr Astrophysical: . Laboratory: • H-maser vs. Hg+ microwave clock: a/a < 3.7  10-14 /yr • Rb vs. Cs microwave clocks: |a/a| < 1.1  10-14 /yr • Hg+ optical vs. Cs microwave clocks: |a/a| < 1.2  10-15 /yr . . . a/a = (-7.2  1.8)  10-16 /yr [J. K. Webb, et al. , Phys. Rev. Lett. 87, 091301 (2001).] . How constant is the fine structure “constant” a?

  7. A B 20,000 Energy (cm-1) . . n ~ 21015 Hz |a/a| i.e. for |a/a| ~ 10-15 /yr  n ~ 2 Hz/yr . n . Ground State 0 rf freq. generator E-field plates atomic beam fluor. n’ atomic freq. standard PMT . levels A and B are highly sensitive to variations in a ain dysprosium n ~ 3-2000 MHz

  8. NONLINEAR MAGNETO-OPTICAL ROTATION Goal: Obtain highest possible sensitivity to magnetic fields. F’ = 0 Use laser light to polarize atoms: • Aligns magnetic dipole moments; • Creates preferred optical axis. F = 1 MF = -1 MF = 0 MF = +1 Magnetic moments precess in magnetic field: Optical axis rotates  causes light polarization to rotate. • = gFmB/grel 1 + (gFmB/grel)2

  9. Paraffin-coated cells smuggled in as Christmas ornaments! (For FSB agents: this is a joke!) Slow relaxation of atomic polarization: grel ~ 1 Hz DB ~ 1 mG ~ 0.1 nT

  10. Pumping andprobing with FM light FM NMOR magnetometry: Phys.Rev.A65, 055403 (2002)

  11. Precision magetometry and atomic EDM measurement using spin-polarized atoms in a buffer gas at cryogenic temperatures • Problem: to measure very small B; to measure electron EDM • Paramagnetic atom magnetometer; He buffer gas at T=4K to increase spin-relaxation time to minutes Measuring the Kerr effect in LHe and the LANL neutron EDM experiment Problem: to measure strong electric fields (50kV/cm) inside a bath of LHe at 300mK. Kerr effect: an initially isotropic medium acquires birefringence when electric field is applied, measure this.

  12. 241 Birge, midnight, 8/25/03

  13. Neutron EDM experiment at LANSCE Light Guides Cells Between Electrodes HV and Ground Electrodes Beam Entrance Window Cosq Coil SQUID Enclosure HV Variable Capacitor

  14. “new” opposite-parity levels Electron EDM exp Noncontact circuit board testing Laser spectroscopy for fundamental symmetry tests • Motivation: BEV exp • Lifetimes, branching ratios, new levels, polarizabilities (Ba) • Unusually large polarizabilities (100 times; for n<10, only smaller than 2s,2p of H)

  15. Probed States Laser Excitation 559 - 569.5 nm Fluorescence ~ 435 nm 6s6p 1P1 6s6p 3P0,1,2 Laser Excitation 554.7 nm 6s21S0 Even Parity Odd Parity

  16. What is the experiment? A test of the spin statistics theorem (SST) for photons. What is the SST?

  17. How we do it Barium

  18. Interaction region

  19. Power Build-up Cavity

  20. Oven Housing w/Collimator

  21. Chamber

  22. Numbers

  23. Experimental Atomic Physics Research in the Budker Group

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