Applications of interferometers and clocks I. Christian Lisdat

Transcription

1 Applications of interferometers and clocks I Christian Lisdat

2 Outline: Keeping time Comparing clocks via the SI, satellites, fibres Interpreting clock comparisons geodesy, temporal variations of fundamental constants, test of relativity, tests of theories beyond normal relativity page 2 of all

3 Time keeping Greenwich Mean Time (1884) 1 s = 1/86400 of the mean solar day Mechanical Clocks f osc 1 Hz daily uncertainty 1 s/d Quartz Clocks (1930s) f osc 60 khz, daily uncertainty 1 ms/d Atomic Cesium Clocks earth rotation variations of ± 1.5 ms A. Scheibe and U. Adelsberger, Z. Phys. 127, 416 (1950) f osc 9.2 GHz daily uncertainty 50 ps/d page 3 of all

4 Time keeping Time labs - UTC(k) BIPM >70 time labs contribute to UTC >500 clocks contribute to UTC UTC is post-processed and disseminated monthly through the BIPM (Circular T) page 4 of all

5 Time keeping Nov28 Dec3 Dec8 Dec13 Dec18 Dec23 Dec28 [UTC-UTC(PTB)]/ns: page 5 of all

6 Time keeping: clock uncertainty (stat.) Idealized case: CSF2 (100% up-time) u A y / 30d month u A y V. Gerginov et al., Metrologia 47, 65 (2010) S. Weyers et al., Metrologia 49, 82 (2012) A. Bauch et al., Metrologia 49, 180 (2012) page 6 of all

7 Time keeping: clock uncertainty Idealized case: CSF2 (100% up-time) (stat.) u A y / 30d month V. Gerginov et al., Metrologia 47, 65 (2010) S. Weyers et al., Metrologia 49, 82 (2012) A. Bauch et al., Metrologia 49, 180 (2012) page 7 of all

8 Time keeping: clock uncertainty (stat.) (syst.) Idealized case: CSF2 (100% up-time) u A y 2 10 ¹³/ 30d ¹⁶ u B x 800 ps (u B y = 3 10 ¹⁶) 1 month V. Gerginov et al., Metrologia 47, 65 (2010) S. Weyers et al., Metrologia 49, 82 (2012) A. Bauch et al., Metrologia 49, 180 (2012) page 8 of all

9 Time keeping: limited uptime Use a reliable flywheel, correct its frequency regularily y(t) 0 t [d] HM flywheel timescale y(t) t [d] y(t) yhm - ysr 0 atomic clock y(t) t [d] 0 availability: 50% t [d] page 9 of all

10 Time keeping: limited uptime Measurement campaign 2015/06 1 month CSF2 u A x u B x u A x u B x Sr clock availability: ~46% C. Grebing et al., Optica 3, 563 (2015) u total x < 200 ps (limited by u extx ) u total x > 800 ps page 10 of all

11 Comparisons: Tests of Physics Einstein Equivalence Principle (EEP): (1) LLI (2) LPI (3) UFF Local Lorentz Invariance Local Position Invariance Universality of Free Fall (aka: weak equivalence principle) outcome of local, non-gravitational experiments are independent of the velocity and orientation of the apparatus! outcome of local, non-gravitational experiments are independent of where and when in the universe they are performed! General Relativity is incompatible with Quantum Physics: Unified Theory must show deviations. Violation of Local Position Invariance α = f(u grav ) or α = f(t) J.-P. Uzan, Varying constants, Gravitation and Cosmology, Living Reviews in Relativity 14, (2011) B. Altschul et al., Quantum Tests of the Einstein Equivalence Principle with the STE-QUEST Space Mission, Advances in Space Research 55, 501 (2015) page 11 of all

12 Comparisons: Tests of Physics Fundamental constants: Are the fundamental constants constant in time and in space? first asked by Paul Dirac Fundamental constants? Need to be pure numbers, as units are arbitrary. J.-P. Uzan, Varying constants, Gravitation and Cosmology, Living Reviews in Relativity 14, (2011) P. A. M. Dirac, The Cosmological Constants, Nature 139, 323 (1937) page 12 of all

13 Comparisons: Examples Local, in the SI Test: local position invariance Sr-1 PTB Non-local, optical ratio Geodesy, redshift Cs PTB Sr-2 PTB Non-local, optical ratio 1 Test: local Lorentz invariance Geodesy Sr SYRTE Yb + PTB Local, optical ratio Test: local Lorentz invariance temporal variation of α page 13 of all

14 Comparisons: Sr Cs Microwave optical: gear required! Time domain: fs-laser with repetitionfrequency f rep Frequency domain: equidistant comb of narrow lines n(m) 1/f rep t J. Hall T. Hänsch ν(m) = ν ceo + m f rep n ceo f rep page 14 of all

15 Comparisons: Sr Cs Microwave optical: gear required! Clock laser n a n a n ceo f rep optical frequency x2 x n ceo BP microwave m f rep page 15 of all

16 Comparisons: Sr Cs Coupling of constants to Sun s gravitational field (LPI)? orbit of Earth through solar gravity potential: ΔU/c² ~ 10 ¹⁰ good for metrology S. Blatt et al., Phys. Rev. Lett. 100, (2008) page 16 of all

17 Comparisons: Sr Cs Coupling of constants to Sun s gravitational field? orbit of Earth through solar gravity potential: ΔU/c² ~ 10 ¹⁰ S. Blatt et al., Phys. Rev. Lett. 100, (2008) R. Le Targat et al., Nature Com. 4, 2109 (2013) page 17 of all

18 Comparisons: Sr PTB Sr SYRTE Paris and Braunschweig are not next door! Which link? Classically: TIC(A) = A - B + d TB + d BS + d SBA + d SA + d RA + S B TIC(B) = B - A + d TA + d AS + d SAB + d SB + d RB + S A [TIC(A) TIC(B)]/2 page 18 of all

19 Comparisons: Sr PTB Sr SYRTE Paris and Braunschweig are not next door! Which link? Classically: D. Piester et al., IEEE UFFC 55, 1906 (2008) page 19 of all

20 Comparisons: Sr PTB Sr SYRTE Paris and Braunschweig are not next door! Which link? Optical! G. Grosche et al., Opt. Lett. 34, 2270 (2009) page 20 of all

21 Comparisons: Sr PTB Sr SYRTE Example: Braunschweig Munich Amplification (bi-directional) required, not compatible with standard infrastructure Predehl et al., Science 336, 441 (2012) page 21 of all

22 Comparisons: Sr PTB Sr SYRTE Ch. Lisdat et al., Nature Comms. 7, (2016) page 22 of all

23 Comparisons: Sr PTB Sr SYRTE total Allan deviation y ( ) Contribution uncertainty (in ) systematic, Sr(SYRTE) 4.1 systematic, Sr(PTB) 1.9 statistical 2 fs combs 0.1 link 0.03 gravity potential 0.4 total averaging time (s) precision after 1000 s of averaging. 10 better 10,000 faster Ch. Lisdat et al., Nature Comms. 7, (2016) page 23 of all

24 Comparisons: Sr PTB Sr SYRTE total Allan deviation y ( ) Sr PTB / Sr SYRTE averaging time (s) Gravity potential correction 247.2(4) 10 ¹⁷ date of measurement (MJD 57092) Ch. Lisdat et al., Nature Comms. 7, (2016) page 24 of all

25 Comparisons: Sr PTB Sr SYRTE Local Lorentz invariance: search for daily modulation due to motion wrt. background Sr PTB / Sr SYRTE date of measurement (MJD 57092) Ch. Lisdat et al., Nature Comms. 7, (2016) animation: A. Bezdek and J. Sebera, Computers & Geosciences 56, 127 (2013), data set: ETOPO2 / EGM2008 page 25 of all

26 Comparisons: Sr PTB Sr SYRTE Local Lorentz invariance: search for daily modulation due to motion wrt. background was done with Rb clocks (GPS) P. Wolf & G. Petit, Phys. Rev. A 56, 4405 (1997) α 10 ⁶ LLI test also with fast ion beams B. Botermann et al., Phys. Rev. Lett. 113, (2014) α 2 10 ⁸ Sr clocks London, Paris, Braunschweig P. Delva et al., Phys. Rev. Lett. 118, (2017) α ⁸ animation: A. Bezdek and J. Sebera, Computers & Geosciences 56, 127 (2013), data set: ETOPO2 / EGM2008 page 26 of all

27 Comparisons: Sr Yb+ PTB s 171 Yb + single-ion clock: Electric-octupole (E3) transition ( 2 S 1/2 2 F 7/2, ν THz) ¹⁸ systematic uncertainty N. Huntemann et al., Phys. Rev. Lett. 116, (2016) page 27 of all

28 Comparisons: Sr Yb+ Measurement in 2015: > 80 h of data acquired. Instability of ¹⁵ (τ/s) -1/2. Statistical uncertainty ¹⁷. Total uncertainty ¹⁷. What is it good for? Consistency tests in other laboratories (e.g. NPL). Search for variations of the finestructure constant α. page 28 of all

29 Comparisons: Sr Yb+ Frequency ratio sensitive to variations of α: 171 Yb + clock highly sensitive. 87 Sr clock insensitive. ΔR/R 6 Δα/α V.V. Flambaum and V.A. Dzuba, Can. J. Phys. 87, 25 (2009) Drift measurement: Combine ratio measurements from 2012 and Uncertainty improved by factor 4! Sr/Yb PTB (preliminary): (1/α) (dα/dt) = 7(5) 10 ¹⁸ / yr Al + /Hg NIST: (1/α) (dα/dt) = 16(23) 10 ¹⁸ / yr T. Rosenband et al., Science 319, 1808 (2008) page 29 of all

30 Comparisons: Sr Yb+ You can test LPI, but also Lorentz invariance: Michelson-Morley experiment E. Fesseler, A. Peters, HU Berlin Ca + experiment: T. Pruttivarasin et al., Nature 517, 592 (2015) page 30 of all

31 Comparisons: Sr Yb+ Preliminary: More than 3 improvement in C 0 (2) over Ca + experiment. page 31 of all

32 Comparisons: Geodesy Optical clocks as sensors: Measure height differences directly. Vision: Define geoid by clocks. ΔU = g Δh gravitational red shift: Δν/ν = ΔU/c 2 height difference 10 cm 1 10 ¹⁷ frequency shift M. Vermeer, Rep. of the Finnish Geod. Insti. 83, 1 (1983) A. Bjerhammar, Bull. Geodesique 59, 207 (1985) page 32 of all

33 Comparisons: Geodesy Transportable clock LSM 100 km fibre INRIM February 2016 page 33 of all

34 Comparisons: Geodesy Absolute Sr-87 frequency: about 1000 m 48.1 Hz Proof-of-principle experiment for chronometric levelling page 34 of all

35 Summary: Primary use: time keeping Compare clocks Look for: temporal variations of fundamental constants violation of Einstein equivalence principle dark matter gravitational waves Means to compare clocks (i.e. links) are very important page 35 of all

36 Physikalisch-Technische Bundesanstalt Braunschweig und Berlin Bundesallee Braunschweig Christian Lisdat Working Group 4.32, Optical lattice clocks phone: