La Mesure du Temps et Tests Fondamentaux

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1 La Mesure du Temps et Tests Fondamentaux Université de Toulouse 20 mai 2010 C. Salomon Laboratoire Kastler Brossel, Ecole Normale Supérieure, Paris

Rosenbusch, D. Rovera, P. Wolf, J. Guéna, A.

2 M. Abgrall, S. Zhang, L. Duchayne, X. Baillard, D.Magalhaes,C. Mandache, M. Fouché, R. Le Targat, P. G. Westergaard, A. Lecallier, F. Chapelet, Y. Lecoq, M. Petersen, M. Santos J. Millo, S. Dawkins, R.Chicireanu, D. Holleville, S. Bize, P. Lemonde, P. Laurent, M. Lours, G. Santarelli, P. Rosenbusch, D. Rovera, P. Wolf, J. Guéna, A. Clairon Laboratoire National d essais Systèmes de Références Temps-Espace, SYRTE Observatoire de Paris M. Tobar, J. Hartnett, A. Luiten, University of Western Australia C. Salomon Laboratoire Kastler Brossel, Ecole Normale Supérieure, Paris Participants

Wieman Bose-Einstein Condensation In atomic gases

3 1997 Nobel prize in physics S. Chu, C. Cohen Tannoudji, W. Phillips Laser manipulation of atoms 2001 Nobel prize in physics E. Cornell, W. Ketterle, C. Wieman Bose-Einstein Condensation In atomic gases 2005 Nobel prize in physics J. Hall, T. Haensch,, R. Glauber Laser precision spectroscopy and optical frequency comb

4 Summary 1) Atomic clocks Frequency stability Accuracy 2) Fundamental tests Search for drift of fundamental constants Precision redshift measurement 3) Perspectives Space clocks, PHARAO/ACES

Time measurement Find a periodic phenomenon: 1) Nature: observation: Earth rotation, moon rotation, orbit of pulsars,.. 2) Human realization: egyptian sandstone, Galileo pendulum.

5 Time measurement Find a periodic phenomenon: 1) Nature: observation: Earth rotation, moon rotation, orbit of pulsars,.. 2) Human realization: egyptian sandstone, Galileo pendulum. simple phenomenon described by a small number of parameters The faster the pendulum, The better is time resolution T 2 l/ g 3) Modern clocks use electromagnetic signals locked to atomic lines

Atomic Clock An oscillator of frequency produces an electromagnetic wave which excites une transition a - b The transition probability a b as a function of has the shape of a resonance curve centred

6 Atomic Clock An oscillator of frequency produces an electromagnetic wave which excites une transition a - b The transition probability a b as a function of has the shape of a resonance curve centred in A = (E b -E a ) / h and of width A servo system forces to stay equal to the atomic frequency A An atomic clock is an oscillator whose frequency is locked to that of an atomic transition The smaller the better is the precision of the locked system Atomic transition Oscillator

7 Precision of Time 1s 1ms 1 s 1ns 1ps GPS Time 100 ps/day 10 ps/day 1 ps/day Optical clocks

8 Ramsey fringes in atomic fountain S/N= 5000 per point

9 Comparison between two Fountains FOM and FO2 (Paris Observatory) S. Bize et al. J. Phys. B 2005 and EFTF 08 SYRTE Best measured stability for fountains! Agreement between the Cesium frequencies:

10 Atomic Fountains 14 fountains in operation at SYRTE, PTB, NIST, USNO, Penn St, IEN, NPL, Metas, JPL, NIM, Sao Carlos,. 8 with accuracy at or below LNE-SYRTE, FR PTB, D NIST, USA

Optical Clocks Trapped Ions and Neutral Atoms Quality of the clock: / x S/N = 2 T x S/N Increase the frequency, increase T, increase S/N Trapped ions : T very long but only one ion in the trap.

11 Optical Clocks Trapped Ions and Neutral Atoms Quality of the clock: / x S/N = 2 T x S/N Increase the frequency, increase T, increase S/N Trapped ions : T very long but only one ion in the trap. Neutral atoms: T long and large numbers: improved stability NIST : Bergquist et al. Hg + :optical transition stability: /2 Accuracy: Al + : A factor of 30 beyond the cesium accuracy! Neutral Sr, accuracy, J. Ye et al. TOKYO, JILA, SYRTE, PTB

NIST Accuracy: : state of the art Rosenband et al., Science 319, 1808 (2008) f Al+ f Hg+ = 1.

12 NIST Accuracy: : state of the art Rosenband et al., Science 319, 1808 (2008) f Al+ f Hg+ = (55) Relative uncertainty: 5.2 x Hg+ systematics: Al+ systematics:

13 Fundamental physics Tests using ultra-stable clocks

14 Search for variations of fundamental constants and Einstein Equivalence Principle In any free falling local reference frame, the result of a non gravitational measurement should not depend upon when it is performed and where it is performed. EEP ensures the universality of the definition of the second It implies the stability of fundamental constants: =e 2 /4 0 hc, m e, G, In particular: the ratio of the transition frequencies in different atoms and molecules should not vary with space and time The EEP can be tested by high resolution frequency measurements regardless of any theoretical assumption EEP revisited by modern theories: g g,, Fundamental constants depend upon local value of : ( ), m( ), Violations of EEP are expected at some level!! For instance: T. Damour, G. Veneziano, PRL 2002

15 Do fundamental physical constants vary with time? G, elm, m e / m p Principle : Compare two or several clocks of different nature as a function of time ex: Microwave clock/microwave clock:, m e /m p, g (i) rubidium and cesium Microwave/Optical clock :, m e /m p, g (i) Optical Clock/Optical clock:

16 SYRTE Rb Comparison Cs Comparison between Rubidium over and 6 years Cesium Hyperfine Structure over ~10 years 10 Relative frequency (10-15 ) Rb Hz Year d Rb 16 ln / year NIST 08 T. Rosenband dtet al., CsScience Express, March 2008 Al + -Hg + optical frequency comparison over 18 months: d / dt= ( )x /year

17 Present tests of cosmological Variations of Oklo test : geochemical analysis of the natural fossil fission reactor in Oklo (Gabon, yr ago) : now Oklo yr 1 Damour, Poliakov, Nucl. Phys. B 480, 37 (1996) Absorption spectroscopy from quasars: (0.5 z 3.5) Controversial results: See Petitjean et al.

18 Laboratory tests versus cosmological tests A priori loss of factor in sensitivity!! ~ 1 year versus years J. Webb et al., PRL 87, (2001) But: ultra-stable and accurate clocks: repeatable measurements independent checks in large numbers of labs choice of hyperfine, fine and optical transitions See S. Karshenboim, Can. J. Phys 78, 639, (2000), J.P. Uzan (2002)

19 Fundamental physics tests with space clocks 1997

20 ACES atomic clocks A cold atom Cesium clock in space Fundamental physics tests Worldwide access

21 ACES Ground laboratories (May 2010) Australia: UWA, CSIRO(Sydney) Austria: Univ. Innsbruck Brazil: Univ. Sao Carlos Canada: NRC China: Shangai Obs, NIM, NTSC Germany: PTB, MPQ, Univ. Hannover, Univ. Düsseldorf, TU Muenchen, Univ. Erlangen France: SYRTE, CNES, Obs. Besançon, OCA, LPL Italy: INRIM, Univ. Firenze Japan: Tokyo Univ., NMIJ, CRL Russia: Vniftri, ILS Novosibirsk Swiss: METAS, ON United King: NPL USA: JPL, NIST, Penn St. Univ., USNO, JILA Taiwan: Telecom research lab Int. Agency: BIPM Total : 35 institutes + theory groups > 300 researchers

ACES Global search for variations of fundamental constants by long distance clock comparisons at 10-17 /year Cs,

22 ACES Global search for variations of fundamental constants by long distance clock comparisons at /year Cs, Rb, Ca, Yb +, Sr Cs, Rb, Sr, Hg H, In+, Mg, Ag Cs, Yb +, Yb +, Cs,Hg + Al +, Sr, Ca, Yb Cs,Rb Cs, Rb, Sr +, Yb +

23 ACES Payload CNES: PHARAO (Atomic clock based on laser cooled Cs atoms SHM (ESA): Active hydrogen maser FCDP (ESA): Clocks comparison and distribution MWL (ESA): T&F transfer link GNSS receiver (ESA) European Laser Timing (ELT) optical link (ESA) Support subsystems (ESA) XPLC: External PL computer PDU: Power distribution unit, Mechanical, thermal subsystems CEPA: Columbus External PL Adapter (ESA-NASA) XPLC FCDP PHARAO PDU S-band MWL SHM Ku-band GNSS Receiver Volume: 1172x867x1246 mm 3 Mass: 227 kg Power: 450 W ASTRIUM

Microwave cavity 3 Magnetic shields and solenoids Fountain : v =

24 PHARAO PHARAO cold cold atom atom clock clock Cooling zone Selection Ramsey Interrogation State detection Cesium reservoir Microwave cavity 3 Magnetic shields and solenoids Fountain : v = 4 m/s, T = 0.5 s PHARAO : v = 0.05 m/s, T = 5 s Ion pump = 1 Hz = 0.1 Hz

25 PHARAO clock

PHARAO Space Clock 1,0 Probabilité 0,8 0,6 0,4 0,2 0,0-300 -200-100 0 100 200 300

26 PHARAO Space Clock 1,0 Probabilité 0,8 0,6 0,4 0,2 0, Cesium tube Frequency Fréquence (Hz) Laser source Performance tests ongoing in CNES Toulouse

Laser Source 20.054 kg, 36W, 30 liters, Vacuum and Air operation, T=10-35 deg.

27 Laser Source kg, 36W, 30 liters, Vacuum and Air operation, T=10-35 deg. Main active components: 4 ECDL 4 DL 6 AOM 30 PZT 11 motors 6 photodiodes 8 peltier coolers

28 Cesium Tube L=900 mm, M= 45 kg, P= 5 W. Detection interrogation Ramsey cavity Tested in fountain capture

29 A Prediction of General Relativity U 2 U 1 U U c Redshift : With clocks ACES: Factor 35 gain over GP-A 1976

Relativistic Geodesy The clock frequency depends on the Earth

have accuracy of 1 10-17 and will improve!

techniques at ~ 30 cm level Possibility to measure the

30 Relativistic Geodesy The clock frequency depends on the Earth gravitational potential per meter Best ground clocks have accuracy of and will improve! (NIST 08) With Competitive ACES: with satellite + levelling techniques at ~ 30 cm level Possibility to measure the potential difference between the two clock locations at level ie 10 cm ACES Geoid H

31 ACES ON COLUMBUS EXTERNAL PLATFORM ACES Current launch date : mid 2013 Mission duration : 18 months to 3 years

32 ACES and Beyond Microwave clocks: stability per day, accuracy: ~ on Earth and in Space Optical clocks: ~10-17 today and towards range (NIST 09) ACES Comparisons between distant clocks at Large improvements on relativity tests and on limits for variations of, g p, M e / M p Applications to GPS & GALILEO monitoring and in Earth Science Currently, clock transport and telecom fiber networks!! Proposed ACES mission follow-on with optical clocks: SOC, EGE, SAGAS,.. Clocks at or below will probe time-dependent Earth potential Far future: dedicated satellite for global time dissemination without Earth potential variations

Status of the ACES/PHARAO mission

XLII nd Rencontres de Moriond,, March 2007 «Gravitational Waves and Experimental Gravity» Status of the ACES/PHARAO mission Noël DIMARCQ, SYRTE, Paris Observatory What is ACES : payload, science objectives,