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Fundamental Physics Fundamental Physics Tests using the LNE-Tests using the LNE-

SYRTE Clock EnsembleSYRTE Clock Ensemble

Rencontres de Moriond and GPhyS colloquium 2011March 25th 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.

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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

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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 εy(t) : fractional frequency fluctuations

Stability: statistical properties of y(t), characterized by the Allan variance y

2()

macroscopic oscillator

atoms

interrogation

correction

output

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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

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mp , g(i) are not fundamental parameters of the Standard Model

mp , g(i), can be related to fundamental parameters of the Standard Model (mq/ΛQCD, ms/ΛQCD, mq=(mu+md)/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 (, me/ΛQCD, mq/ΛQCD)

Alternatively, one can use (, µ=me/mp, mq/mp)

V. V. Flambaum and A. F. Tedesco, PRC 73, 055501 (2006)

V. V. Flambaum et al., PRD 69, 115006 (2004)

)/(

)/(

)/(

)/(

QCDq

QCDq

QCDs

QCDs

m

m

m

m

It is often assumed that :

Atomic Transitions and Fundamental Constants

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Ka Kq Ke

Rb hfs 2.34 -0.064 1

Cs hfs 2.83 -0.039 1

H opt 0 0 0

Yb+ opt 0.88 0 0

Hg+ opt -3.2 0 0

Dy comb. 1.5 107 0 0

Sensitivity coefficients

Dysprosium : RF transition between 2 accidentally degenerated electronic states of different parity

K, Ke : accuracy at the percent level or better

Kq : 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

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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

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LNE-SYRTE ATOMIC CLOCK ENSEMBLE

Hg, opt

Cs, µW

Cs, µW

Rb, Cs, µW

H, µW

Phaselock loop

~1000 s

FO1 fountain

FO2 fountain

FOM transportable fountain

Optical lattice clock

Optical lattice clock

Macroscopic oscillator

Cryogenic sapphire Osc.

H-maser

Sr, opt

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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, 40Ca+ 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)

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Atomic fountain clocks

-100 -50 0 50 1000.0

0.2

0.4

0.6

0.8

1.0

-1.0 -0.5 0.0 0.5 1.00.0

0.2

0.4

0.6

0.8

1.0

detuning (Hz)

0.94 Hz

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

133Cs levels (87Rb similar)

Ramsey fringes

Best accuracy: 4x10-16

Real-time control of collision shift with adiabatic passage: Phys. Rev. Lett. 89, 233004 (2002)

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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)

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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

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Measurements of the Rb hyperfine splitting vs timeWeighted 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: 87Rb 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)

(-2.0±1.2)

(-2.0±1.2)

(1.7 standard deviation)

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Variation of with gravitation potential

Variation with space

Rb vs Cs: Search for annual terms

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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

-200 -100 0 100 200

0.0

0.1

0.2

0.3

0.4

Tra

nsi

tion

pro

ba

bili

ty

detuning [kHz]

Spectroscopy in the Lamb-Dicke regime

Carrier transition, essentially unaffected by external motion

Trapped ion clocks

Lattice clocks

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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

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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)

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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

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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

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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 229Th …