Clock based on nuclear spin precession spin-clock

Transcription

1 Clock based on nuclear spin precession spin-clock signal (a.u.) detector t exp - T (G. D. Cates, et al., Phys. Rev. A 37, 877) T T T, field T, field 4 4R 75D B, z B, y B, x R 4 p B (ms ) T 00h Long T : p ~ mbar, R ~3cm, B ~ T

2 B SQUID [pt] B SQUID [pt] 3 He free spin-precession signal SQUID (intrinsic noise of SQUID: ft/hz) d R -5 0,0 0, 0,4 time [s] Signal: 3 R B[ pt] 0 p[ mbar] P d parameters: p He = -3 mbar ; P = 0-50% R =.9 cm; d = 6cm B = 0-30 pt system noise inside BMSR- ~ ft/hz time [h] Note: At present, the Xe spin coherence time T is limited to 3 h < T < 4 h due to wall relaxation

3 3 He / 9 Xe clock comparison to get rid of magnetic field drifts B [nt] drift ~ pt/h Hz/h B t [h] 9 Xe 3 (4,7 Hz) He (3 Hz)! const. 0 He He He L, He Xe L, Xe Xe Xe

4 The detection of the free precession of co-located 3 He/ 9 Xe sample spins can be used as ultra-sensitive probe for non-magnetic spin interactions of type: Search for a Lorentz violating sidereal modulation of the Larmor frequency ~ V ( r)/ b ˆ / Search for spin-dependent short-range interactions Search for EDM of Xenon V nonmagn. a PM B PM V( r)/ c nˆ / V( r)/ dn E / Observable: He L, He L, Xe Xe 0

5 Search for a Lorentz violating sidereal modulation preferred direction in space-time

6 Modern Tests of Lorentz violation Topics: searches for CPT and Lorentz violations involving -birefringence and dispersion from cosmological sources -clock-comparison measurements -CMB polarization -collider experiments -electromagnetic resonant cavities -equivalence principle -gauge and Higgs particles -high-energy astrophysical observations -laboratory and gravimetric tests of gravity -matter interferometry -neutrino oscillations -oscillations and decays of K, B, D mesons -particle-antiparticle comparisons -space-based missions -spectroscopy of hydrogen and antihydrogen -spin-polarized matter Theoretical studies of CPT and Lorentz biviolation involving -physical effects at the level of the SM, General Relativity, and beyond -origins and mechanisms for violations classical and quantum issues in field theory, particle physics, gravity, and strings

7 Standard-Model Extension - matter sector - A. Kostelecky and C. Lane: Phys. Rev. D 60, 600 (999) Modified Dirac equation for a free spin ½ particle (w=e,p,n) i m w a w b w i g H w w w w w w 5 ie f 5 ic id 5 0 standard DE CPT violating CPT preserving terms Lorentz violating terms a Experimental access: w w, b,... w coupling strength m M w Planck m w Cs- fountain Wolf et al., Torsion pendulum Antihydrogen spectroscopy Astrophysics Hg/Cs comparison UCN/Hg comparison He/Xe maser K/He co-magnetometer B.Heckel et al. PRD 78 (008) clock comparison experiments n b

8 Coupling of spin field: ~ V b to background LAB B, ˆ b H B b B h h b cos( ˆ, Bˆ ) Zeeman LV C b εˆ Bˆ cosmic microwave background v = 368 km/s T dip 3.3 mk Zeeman LV ~ a ssin(ωs t) a ccos(ωs t)

9 In terms of frequency: Kostelecky et al., Phys. Rev. D 60, 600 (999) free neutron: n : µ = -.93 µ K Schmidt-Model a max s Lab-frame with quantization axis z nhz (95% C.L.) (X,Y,Z) non-rotating frame with Z along Earth s rotation axis PTB Berlin: = 5,564 0 north = 8 0 (north-south) 3 He: µ = -.76 µ K 9 Xe: µ = µ K cos cos cos ~ n ~ n ~ n sin 3.5 b 0.0 d 0.0 gd, b ~ n GeV (95% C. L. ) PRD 8 (00) 90

10 () rotation of B-field (quantization axis) 5 subruns (~ 4 h each) Sequence: field rotation (45 0 ) :.5 min measurement (static):.5 min BMSR- S expected LV-signal: ~ sin t sin ( t),0 s N 0,8 0,6 LV (t) [a.u.] 0,4 0, 0,0-0, -0,4-0,6-0,8 -, time (h)

11 Phase residuals: total data taking time: 65 h (90 h March 009 ) ~.8 gain in SNR: -3 gain due to CRLB power law (~/T 3/ ) :.8 reduction of correlated error: ~ 7 March 009 subrun for comparison (shifted by 0.04 rad) overall gain in sensitivity: ~ 00

12 Change of the absolute field gradient during rotation and its effect on T T B data analysis ongoing

13 Conclusion and Outlook 3 He, 9 Xe spin clock based on free spin precession long spin coherence times,, 3 T He 60hours T Xe 4 hours ( T He 4 h,, March 0 run ) ( T ( Xe) T, wall ~ h) Search for neutron spin coupling to a Lorentz and CPT-violating background field ~ V ( r)/ b ˆ / K- 3 He and 3 He/ 9 Xe co-magnetometer set the tightest limits on SME-parameters K- 3 He co-magnetometer : 3 He- 9 Xe co-magnetometer : b ~ n b ~ n GeV (68% C. L.) GeV (95% C. L. ) PRL 05, 5604 (00) PRD 8, 90 (00) March 0 run: expected gain in sensitivity ~ 00 to trace LV interactions

14 Search for a new pseudoscalar boson (Axion-like particle) Gerardus 't Hooft,: QCD has a non-trivial vacuum structure that in principle permits CP-violation from neutron EDM we get: d n ecm Original proposal for Axion ( R. Peccei, H.Quinn PRL 38(977),440) as possible solution to the Strong CP Problem that cancels the CP violating term in the QCD Lagrangian Modern interest: Dark Matter candidate. All couplings to matter are weak Axions, if they exist, will be very light and will mediate a macroscopic CP- force m a m f a f 6eV 0 GeV f a f a : energy scale P.Q.-symmetry is spontaneously broken

15 Short range interaction of the axion Yukawa-type potential with monopole-dipole coupling: V ( r) nˆ r r gsg p with :, 8 m N N N g s axion n g p n N N e r / m c a polarized matter n n n (Moody and Wilczek PRD (984)) ev m nˆ nˆ m a 0 0 ev m unpolarized matter N Faxion Faxion

16 How to measure? B L, ( t) B( t) He He 3 He Position: Close unpolarized matter Close ( t) ( t) L, He (Pb-glass, BGO) with: V / 3 He ( t) ( t) Far L, He Position: Far Requirement: ( t) const. L,He Close Far

17 Dewar housing the LT c -SQUIDs Pb-glass (009 run) BGO crystal (00 run) 3 He/ 9 Xe cell

18 Exclusion Plot for new spin-dependent forces Hammond 993 Ni 999 g N s g e p Youdin 996 Adelberger 0 gap of 0.5 mm g N s g our result 00 n p our result 009