Spectroscopy of lithium ions at 34% of the speed of light with sub-doppler linewidth

Transcription

1 Towards a test of time dilation: Spectroscopy of lithium ions at 34% of the speed of light with sub-doppler linewidth /3

2 Outline Introduction: test theories for SRT Tools for modern test of time dilation Status of the experiment at GSI and first signals Results & Outlook 1/3

3 Why testing time dilation? Lorentz invariance is a fundamental constituent in the standard model of particle physics as well as in the theory of general relativity Special Relativity Lorentz transformations Standard Model General Relativity G electro-magnetic nuclear weak nuclear strong force force force gravitational force In some models hypothetical Lorentz violations are included Lorentz violation could be a revealed by experiment as a signature of new physics Hypothetical deviations can be included as quantitative parameters in test theories /3

4 Dynamical / kinematical test theory Any test theory gives: a base to compare different experiments and parameterize possible violations Kinematical test theory (e.g. Robertson, Mansouri & Sexl) generalized Lorentz transformation preferred frame assumed only a few parameters are needed Dynamical test theory (e.g. Standard Model Extension) (Kostelecký et al.) small extension of the SM Lagrangian can describe particle couplings several hundreds of parameters - vacuum contains background with vectors and pseudo vectors 3/3

5 Dynamical / kinematical test theory Any test theory gives: a base to compare different experiments and parameterize possible violations Kinematical test theory (e.g. Robertson, Mansouri & Sexl) generalized Lorentz transformation preferred frame assumed only a few parameters are needed BUT! generalized Lorentz transformation Dynamical test theory (e.g. Standard Model Extension) (Kostelecký et al.) small extension of the SM Lagrangian can describe particle couplings several hundreds of parameters No minimum limit for Lorentz violation is stated by (test) theories! - vacuum contains background with vectors and pseudo vectors 3/3

6 Mansouri-Sexl (MS) test theory Generalized Lorentz transformations preferred frame lab. frame CMB for special relativity -1 γ -1 Assumptions: preferred ether frame Σ (CMB?) only in Σ the light speed is isotropic lab. frame is moving with along the x-axis expansion in velocity terms time dilation (Ives-Stilwell) isotropy of space (Michelson-Morley & Kennedy-Thorndike) Christian Novotny PSAS 008 4/3

7 Time dilation in the MS-framework Generalized Lorentz transformations Three inertial systems: r u CMB clock frame lead to a modified Lorentz factor: γ MS [ ( Test parameter r w is a function of Christian Novotny ) ] r r = γ 1 + δα β + β w +... PSAS 008 = 350 km/s 4/3

8 Time dilation in the MS-framework Generalized Lorentz transformations Three inertial systems: r u CMB clock frame lead to a modified Lorentz factor: γ MS [ ( we neglect sidereal term Test parameter is a function of β Christian Novotny ) ] r r = γ 1 + δα β + β w +... PSAS 008 r w = 350 km/s << r β ~ km/s 4/3

9 Source Test of time dilation relativistic Doppler effect Observer β = v c 0 5/3

10 Source Test of time dilation relativistic Doppler effect Observer β = v c 0 Einstein proposed 1907: = γ 0 β 0 Experimentally impossible to measure light emitted only at 90 5/3

11 Source Test of time dilation relativistic Doppler effect Observer β = v c 0 = p a γ ( 1 β) γ ( 1+ β ) a 0 0 p = γ = Ives-Stilwell type experiment? 0 ( 1 β ) 1+ ε β 0 θ = 180 Source θ = 0 5/3

12 Source Test of time dilation relativistic Doppler effect Observer β = v c 0 = 0 p a γ ( 1 β) γ ( 1+ β ) a 0 p = γ = γ = Ives-Stilwell type experiment 0? 1+ ε ( 1 β ) 1 θ = 180 Source θ = 0 γ MS ( ) 4 1 β = 1+ δα β + ( δα + δα ) β... MS + γ 0 β 0 ε Time Dilation can be tested via comparing three optical frequencies 5/3

13 Evolution of time dilation tests 6/3

14 Modern Ives-Stilwell experiment frequencies has to been known very accurate Precision Spectroscopy a 0 p = 1+ δα β the higher the clock velocity, the higher the sensitivity to δα Storage Ring moving direction of the clock (metastable Lithium ions) β blue shifted laser red shifted laser v = %c detection 7/3

15 Modern Ives-Stilwell experiment Testing Lorentz transformation via measuring of the optical frequencies β moving absorber = clock = γ 1 p Laser P 0 ( + β) 0 PM Laser A = γ 1 a 0 ( β) Testing time dilation via three optical frequencies a 0 p = γ? ( 1 β ) 1 a 0 p = 1+ δα β 8/3

16 The clock Helium-like lithium ion in the metastable triplet state closed two level system s 3 S 1 p 3 P natural line width 3.7 MHz can be accelerated to and stored at high velocities with superb beam qualities 9/3

17 Spectroscopy in a storage ring Doppler-broadened Spectroscopy 7/ velocity distribution tune Laser 5/ Λ - Spectroscopy fix Laser 5/ 5/ tune Laser 3/ first-order Doppler-free peak Both laser are in resonance with the same velocity group β 0 a p = 1 10/3

18 (High) relativistic 7 Li nm 580 nm nm 386 nm 11/3

19 The GSI facility ECR-Ion source equipped with LiF 58 MeV/u (without cooling) RFQ & HI (1.4MeV/u) Unilac (8 MeV/u) with v = 34%c to ESR 1/3

20 The experimental storage ring ESR Electroncooler Reinjectionchannel Extraction from SIS Circumference 108 m Ion current ~5 µa Ion beam storage time 10 8 Ions τ = 0 s 3 min magn. rigidity 10 Tm Momentum spread Δp/p ~ 10-6 t = 0 Target & Experimentsection (field free) 6 Dipole magnets 4 system of quadrupole & multipole magnets 7 Li + 14 N + 10m t = 0s 13/3

21 Experimental section 50 m glass fibre Laser tower 780 nm Laser beam λ a = 780 nm Flight direction 7 Li + -Ionen Scraper 30 m Photomultiplier Revolution frequency ~1 MHz Scraper Target & Experimentsection (field free) Laser tower 386 nm Laser beam λ p =386 nm 13 m photonic fibre 14/3

22 Experimental section 50 m glass fibre Laser tower 780 nm Laser beam λ a = 780 nm Flight direction 7 Li + -Ionen Scraper 30 m Photomultiplier Revolution frequency ~1 MHz Scraper Target & Experimentsection (field free) Laser tower 386 nm Laser beam λ p =386 nm 13 m photonic fibre 14/3

23 Laser system (simplified) antiparallel excitation feed back loop frequency reference on rubidium via fm-saturation spectroscopy (< 1 MHz) Laser diode parallel excitation Wave-meter frequency reference wave meter (~100 MHz) (more accurate reference tested but not applied in beam time yet) AOM to ESR 780 nm Wave-meter to ESR 386 nm Verdi V18 & Ti:Sa 780 nm 77 nm SHG 15/3 AOM

24 Characteristics of the metastable 7 Li + 7/ λ 780nm tuned Laser fix Laser 5/ Linewidth Δ 0 = 1.09 GHz ± 0.08 GHz Lifetime of the metastable τ = 50 s [C. Novotny et al., Hyperfine Interact. 171 (006) 57] 16/3

25 Parallel lambda spectroscopy two red lasers : fix Laser tune Laser Δ = 14GHz difference of the two lasers first-order Doppler-free spectroscopy: linewidth: (70 16) MHz (10 times wider than the natural one) λ 780nm both lasers from one site (through one fiber) no uncertainty in laser-laser alignment less background higher signal (less filters) 17/3

26 Antiparallel lambda spectroscopy fix Laser tune Laser red & blue laser Δ = 79 ± 5 MHz (laboratory frame) Δ = 109 ± 3 MHz (ion frame) Peak position: ± 10 MHz 87 Rb 18/3

27 Impact on the test parameter Using TSR to fix δα and ESR for second order terms δα β + 4 p a 7 ( δα + δα ) β < 1 = δα TSR < [S. Reinhardt, et al. Nature Physics 3 (007) 861 ] Δ ESR δα < 9 10 Improvement by factor of 8 compared to former upper limit measured on H 84%c [D.W. MacArthur et al., PRL 56 (1986) 8] 6 p a δα 1= δα β ESR = (7 ± 11) consequences for δα ESR 13 δα TSR = (4.8 ± 8.4) 10-8 TSR 19/3

28 Iodine 77 nm to frequency comb & wave meter temperature of the cell 500 C 77nm Ti:Sa EOM (5 MHz) temperature of the cold finger 30 C AOM (+80 MHz) PD calibrated transition for the SRT experiment P(4) 1-14 (77nm) a 1 : ( ± 0.30) MHz a 1 -a 10 : ( ± 4) khz a 1 -a 15 : ( ± 4) khz [S. Reinhardt et al., Opt. Com. 74 (007) 354] 0/3

29 Extended laser system 1/3

30 Summary Presented : upper bound on test parameter α < (at TSR) the possibility of precision spectroscopy in high relativistic ion beams improved upper limit for second-order deviations by a factor 8 (at ESR) the feasibility for a new first-order upper limit calibration of iodine transitions at 77 nm Next steps : beam time with full frequency resolution (Δ <1 MHz) systematic investigations (switching schemes, geometrical uncertainties, etc ) applying saturation spectroscopy /3

31 The SRT-Collaboration 1 3 C. Novotny 1, S. Reinhardt,4, S. Karpuk 1, B. Bernhardt 4, D. Bing, G. Ewald 3, C. Geppert, G. Gwinner 5, T. W. Hänsch 4, R. Holzwarth 4, G. Huber 1, H.-J. Kluge 3, T. Kühl 1,3, W. Nörtershäuser 1,3, G. Saathoff,4, D. Schwalm,T. Stöhlker 3, T. Udem 4, A. Wolf 5 4 3/3