1. 1 Fundamental Physics Tests using the LNE-SYRTE Clock Ensemble Rencontres de Moriond and GPhyS colloquium 2011 March 25 th 2011 La Thuile, Aosta valley, Italy M. Abgrall, S. Bize, A. Clairon, J. Guéna, P. Laurent, Y. Le Coq, P. Lemonde, J. Lodewyck, L. Lorini, S. Mejri, J. Millo, J.J. McFerran, P. Rosenbusch, D. Rovera, G. Santarelli, M.E. Tobar, P. Westergaard, P. Wolf, L. Yi, et al.

2. 2 Outline Atomic clocks and fundamental constants Rb vs Cs in atomic fountain clocks Some optical clock comparisons Constraints to variation of constants with time and gravitation potential Prospects

3. 3 Principle of atomic clocks Goal: deliver a signal with stable and universal frequency Bohr frequencies of unperturbed atoms are expected to be stable and universal Building blocks of an atomic clock Can be done with microwave or optical frequencies, with neutral atoms, ions or molecules ε : fractional frequency offset Accuracy: overall uncertainty on ε y(t) : fractional frequency fluctuations Stability: statistical properties of y(t), characterized by the Allan variance  y 2 (  ) macroscopic oscillator atoms interrogation correction output

4. 4 Atomic Transitions and Fundamental Constants Atomic transitions and fundamental constants  Hyperfine transition  Electronic transition  Molecular vibration  Molecular rotation Actual measurements: ratio of frequencies Electronic transitions test α alone (electroweak interaction) Hyperfine and molecular transitions bring sensitivity to the strong interaction

5. 5 m p, g (i) are not fundamental parameters of the Standard Model m p, g (i), can be related to fundamental parameters of the Standard Model (m q /Λ QCD, m s /Λ QCD, m q =(m u +m d )/2) Recent, accurate calculations have been done for some relevant transitions Any atomic transition (i) has a sensitivity to one particular combination of only 3 parameters ( , m e /Λ QCD, m q /Λ QCD ) Alternatively, one can use ( , µ=m e /m p, m q /m p ) V. V. Flambaum and A. F. Tedesco, PRC 73, 055501 (2006) V. V. Flambaum et al., PRD 69, 115006 (2004) It is often assumed that : Atomic Transitions and Fundamental Constants

6. 6 KaKa KqKq KeKe Rb hfs2.34-0.0641 Cs hfs2.83-0.0391 H opt000 Yb + opt0.8800 Hg + opt-3.200 Dy comb.1.5 10 7 00 Sensitivity coefficients Dysprosium : RF transition between 2 accidentally degenerated electronic states of different parity K , K e : accuracy at the percent level or better K q : accuracy ? PR C73, 055501 (2006) Dzuba et al., Phys. Rev. A 68, 022506 (2003) In some diatomic molecules: cancellation between hyperfine and rotational energies also leads to large (2-3 orders of magnitude enhancement) Flambaum, PRA 73, 034101 (2006) Thorium 229 : nuclear transition in the optical domain (163nm) between 2 nearly degenerated nuclear states E. Peik and Chr. Tamm, Europhys. Lett.61, 181 (2003) E. Peik et al., arXiv:0812.3548v2 Highly charged ions Flambaum, PRL 105, 120801 (2010) S. G. Porsev et al., PRL 105, 182501 (2010) Note: if a variation is detected, these coefficients provide a way to have a clear evidence from experiments with multiple clocks

7. 7 Variation with time  Repeated measurements between clock A and clock B over few years Variation with gravitation potential  Several measurements per year, search for a modulation with annual period and phase origin at the perihelion Variation with space  Several measurements per year, search modulation with annual period and arbitrary phase 3 types of searches Annual modulation of the Sun gravitation potential at the Earth : ~1.6 10 -10

8. 8 LNE-SYRTE ATOMIC CLOCK ENSEMBLE Hg, opt Cs, µW Rb, Cs, µW H, µW Phaselock loop  ~1000 s FO1 fountain FO2 fountain FOM transportable fountain Optical lattice clock Macroscopic oscillator Cryogenic sapphire Osc. H-maser Sr, opt

9. 9 Time and frequency metrology  Fountain comparisons: accuracy ~4x10 -16  Secondary definition the SI second based on Rb hfs  Calibration of international time (LNE-SYRTE: ~50% of all calibrations)  Absolute frequency measurement of optical frequencies in the lab (Sr) and abroad (H(1S-2S) at MPQ, 40 Ca + in Innsbruck) Fundamental physics tests  Local Lorentz invariance in photon sector (CSO vs H-maser) and in the matter sector (Zeeman transitions in Cs fountain)  Stability of fundamental constants with time (Rb vs Cs, H(1S-2S) vs Cs, Sr vs Cs) and gravitation potential (Sr vs Cs) Development of Sr and Hg optical lattice clock PHARAO/ACES cold Cs atom space clock  Support the development of the project  Ground segment of PHARAO/ACES mission Applications of LNE-SYRTE clock ensemble Gen. Rel. Grav. 36, 2351 (2004) PR D 70, 051902(R) (2004) J. Phys. B 38, S44 (2005) C.R. Physique 5, 829 (2004) PRL 90, 150801 (2003) PRL 92, 230802 (2004) PRL 84, 5496 (2000) PRL 102, 023002 (2009) PRL 100, 053001 (2008) PRA, 72, 033409 (2005) PRA 79, 061401 (2009) PRL 96, 103003 (2006) PRL 97, 130801 (2006) Eur. Phys. J. D 48, 11-17 (2008) PRL 100, 140801 (2008) PRA 68, 030501 (2003) PRD 81, 022003 (2010) PRL 96, 060801 (2006) PRL 90, 060402 (2003) PRL 101, 183004 (2008) PRA 79, 053829 (2009) Appl Phys B 99, 41 (2010) Opt. Lett. 35, 3078 (2010) PRL 106, 073005 (2011)

10. 10 Atomic fountain clocks More than 10 fountains in operation (LNE-SYRTE, PTB, NIST, USNO, JPL, NICT, NMIJ, METAS, INRIM, NPL, USP,…) with an accuracy a few 10 -15 and <10 -15 for a few of them. Atomic quality factor: Best frequency stability (~ Quantum Projection Noise limited): 1.6x10 -14 @1s 133 Cs levels ( 87 Rb similar) Ramsey fringes Best accuracy: 4x10 -16 Real-time control of collision shift with adiabatic passage: Phys. Rev. Lett. 89, 233004 (2002)

11. 11 LNE-SYRTE FO2: a dual Rb and Cs fountain Dichroic collimators  co-located optical molasses Dual Ramsey microwave cavity Synchronized and yet flexible computer systems with two independent optical tables Almost continuous dual clock operation since 2009 Cs 9.192..GHz Rb 6.834…GHz J. Guéna et al., IEEE Trans. on UFFC 57, 647 (2010)

12. 12 Example of a Rb vs Cs measurement (2007/2008) 16 Nov 2007-30 Jan 2008: 51 effective days of synchronous data Total uncertainty 1.1x10 -15 Resolution 6x10 -17 at 50 days (assuming white noise) J. Guéna et al., IEEE Trans. on UFFC 57, 647 (2010) S. Bize et al., J. Phys. B: At. Mol. Opt. Phys. 38, S44 (2005) S. Bize et al., C.R. Physique 5, 829 (2004) H. Marion et al., Phys. Rev. Lett. 90, 150801 (2003) Y. Sortais et al., Phys. Scripta T95, 50 (2001) S. Bize et al., Europhys. Lett. 45, 558 (1999) (FO2-Rb) (2007) =6 834 682 610.904 309 (8) Hz Investigation of the Distributed Cavity Phase shift reduces this uncertainty to <10 -16 Collaboration with K. Gibble (PennState Univ., USA) PRL to appear in 1 or 2 weeks

13. 13 Measurements of the Rb hyperfine splitting vs time Weighted least square fit gives: With QED calculations: With QCD calculations: V. V. Flambaum and A. F. Tedesco, PR C73, 055501 (2006) J. Prestage, et al., PRL (1995), V. Dzuba, et al., PRL (1999) Note: 87 Rb hyperfine transition was the first secondary representation of the SI second. BIPM CCTF recommended value (based on LNE-SYRTE 2002 data): Rb (CCTF)= 6 834 682 610.904 324 (21) Hz Improvement by 5.8 wrt PRL 90, 150801 (2003) (-2.0±1.2) (1.7 standard deviation)

14. 14 Variation of with gravitation potential Variation with space Rb vs Cs: Search for annual terms

15. 15 The clock transition is in the optical domain allowing improved accuracy (talk by P. Lemonde) Confinement into the Lamb-Dicke regime is used to dramatically reduce the effects of external motion  Mandatory to gain over µWave clocks: Optical clocks Spectroscopy in the Lamb-Dicke regime Carrier transition, essentially unaffected by external motion Trapped ion clocks Lattice clocks

16. 16 Frequency ratio of Al + and Hg + single ion clocks at NIST T. Rosenband et al., Science 319, 1808 (2008) Fractional uncertainty: 5.2x10 -17 Since then improved to 8.6x10 -18 Chou et al., PRL 104, 070802 (2010) in units of 10 -18

17. 17 Measurements against Cs fountains at JILA, Tokyo Univ. and SYRTE Strontium optical lattice clock’s absolute frequency  3 independent measurements in excellent agreement to within a few 10 -15  Very different trap depths (150 kHz to 1.5 MHz) and geometries  Close to fountain accuracy limit Phys. Rev. Lett. 100, 140801 (2008) Eur. Phys. J. D 48, 11 (2008)

18. 18 LNE-SYRTE (2011) NIST, (PRL 2007) PTB, (PRL 2004), (arXiv 2006) MPQ + LNE-SYRTE (PRL 2004) Berkeley, (PRL 2007) Tokyo, JILA, LNE-SYRTE, (PRL 2008) Overview of recent measurements NIST, (Science 2008) INDEPENDENT OF COSMOLOGICAL MODELS Least squares fit

19. 19 Constraint to a variation of constants with gravity Berkeley, PRA 76, 062104 (2007) SYRTE (2011) NIST, SYRTE, PTB, PRL 98, 070802 (2007) SYRTE, Tokyo, JILA, PRL 100, 140801 (2008) NIST, PRL 98, 070801 (2007) Least squares fit INDEPENDENT OF COSMOLOGICAL MODELS

20. 20 Summary and Prospects Atomic clocks provide high sensitivity measurements of present day variation of constants  Clock tests are independent of any cosmological model  Complement tests at higher redshift (geological and cosmological time scale)   Inputs for developing unified theories Improvements in these tests will come from:  Improvements in clock accuracy  As fast as in the last decade ?  Improvements in remote comparison methods  Coherent optical fiber links  Use PHARAO/ACES mission on ISS (talk by L. Cacciapuoti),  In the future, mission like USTAR dedicated to satellite remote comparisons  New atomic and molecular systems with enhanced sensitivities  Molecules  Highly charged ions  Nuclear transition in 229 Th  …