Fundamental Physics Tests using the LNE-SYRTE Clock Ensemble

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Fundamental Physics Tests using the LNE-SYRTE
Clock Ensemble
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.
Rencontres de Moriond and GPhyS colloquium
2011 March 25th 2011 La Thuile, Aosta valley,
Italy
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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
macroscopic oscillator
e fractional frequency offset Accuracy overall
uncertainty on e
output
y(t) fractional frequency fluctuations Stability
statistical properties of y(t), characterized
by the Allan variance ?y2(?)
atoms
correction
interrogation
Can be done with microwave or optical
frequencies, with neutral atoms, ions or molecules
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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 a alone (electroweak
  interaction)
• Hyperfine and molecular transitions bring
  sensitivity to the strong interaction

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Atomic Transitions and Fundamental Constants

• 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/?QCD,
  ms/?QCD, mq(mumd)/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/?QCD, mq/?QCD)
• Alternatively, one can use (?, µme/mp, mq/mp)

It is often assumed that
V. V. Flambaum et al., PRD 69, 115006 (2004)
V. V. Flambaum and A. F. Tedesco, PRC 73, 055501
(2006)
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Sensitivity coefficients
K?, Ke accuracy at the percent level or better
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
Kq accuracy ?
PR C73, 055501 (2006)
Note if a variation is detected, these
coefficients provide a way to have a clear
evidence from experiments with multiple clocks
Dysprosium RF transition between 2 accidentally
degenerated electronic states of different parity
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)
Highly charged ions
Flambaum, PRL 105, 120801 (2010)
Thorium 229 nuclear transition in the optical
domain (163nm) between 2 nearly degenerated
nuclear states
S. G. Porsev et al., PRL 105, 182501 (2010)
E. Peik and Chr. Tamm, Europhys. Lett. 61, 181
(2003)
E. Peik et al., arXiv0812.3548v2
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3 types of searches

• 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

Annual modulation of the Sun gravitation
potential at the Earth
1.6 10-10
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LNE-SYRTE ATOMIC CLOCK ENSEMBLE
H-maser
H, µW
FO1 fountain
Cryogenic sapphire Osc.
Phaselock loop ?1000 s
Optical lattice clock
Macroscopic oscillator
Hg, opt
Cs, µW
FO2 fountain
Optical lattice clock
FOM transportable fountain
Sr, opt
Rb, Cs, µW
Cs, µW
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Applications of LNE-SYRTE clock ensemble

• 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

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 96, 060801 (2006)
PRL 100, 053001 (2008)
Gen. Rel. Grav. 36, 2351 (2004) PR D 70,
051902(R) (2004)
PRD 81, 022003 (2010)
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)
PRL 100, 140801 (2008)
PRL 97, 130801 (2006)
PRA 68, 030501 (2003)
Eur. Phys. J. D 48, 11-17 (2008)
PRA, 72, 033409 (2005)
PRL 96, 103003 (2006)
PRA 79, 061401 (2009)
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Atomic fountain clocks
133Cs levels (87Rb similar)
Ramsey fringes
Atomic quality factor
Best frequency stability ( Quantum Projection
Noise limited) 1.6x10-14 _at_1s
Best accuracy 4x10-16
Real-time control of collision shift with
adiabatic passage Phys. Rev. Lett. 89, 233004
(2002)
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
lt10-15 for a few of them.
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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

J. Guéna et al., IEEE Trans. on UFFC 57, 647
(2010)
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Example of a Rb vs Cs measurement (2007/2008)
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)
16 Nov 2007-30 Jan 2008 51 effective days of
synchronous data
Resolution 6x10-17 at 50 days (assuming white
noise)
?(FO2-Rb) (2007) 6 834 682 610.904 309 (8) Hz
Total uncertainty 1.1x10-15
Investigation of the Distributed Cavity Phase
shift reduces this uncertainty to
lt10-16 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 time
Weighted least square fit gives
(-2.01.2)
(1.7 standard deviation)
Improvement by 5.8 wrt PRL 90, 150801 (2003)
With QED calculations
J. Prestage, et al., PRL (1995), V. Dzuba, et
al., PRL (1999)
(-2.01.2)
With QCD calculations
V. V. Flambaum and A. F. Tedesco, PR C73, 055501
(2006)
(-2.01.2)
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
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Rb vs Cs Search for annual terms

• Variation of with gravitation potential
• Variation with space

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Optical clocks

• 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

Trapped ion clocks
Spectroscopy in the Lamb-Dicke regime
Lattice clocks
Carrier transition, essentially unaffected by
external motion
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Frequency ratio of Al and Hg single ion clocks
at NIST
Fractional uncertainty 5.2x10-17
in units of 10-18
Since then improved to 8.6x10-18
Chou et al., PRL 104, 070802 (2010)
T. Rosenband et al., Science 319, 1808 (2008)
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Strontium optical lattice clocks absolute
frequency

• Measurements against Cs fountains at JILA, Tokyo
  Univ. and SYRTE

Eur. Phys. J. D 48, 11 (2008)

• 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)
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Overview of recent measurements
LNE-SYRTE (2011)
MPQ LNE-SYRTE (PRL 2004)
Tokyo, JILA, LNE-SYRTE, (PRL 2008)
NIST, (PRL 2007)
Berkeley, (PRL 2007)
PTB, (PRL 2004), (arXiv 2006)
NIST, (Science 2008)
Least squares fit
INDEPENDENT OF COSMOLOGICAL MODELS
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Constraint to a variation of constants with
gravity
SYRTE (2011)
NIST, SYRTE, PTB, PRL 98, 070802 (2007)
SYRTE, Tokyo, JILA, PRL 100, 140801 (2008)
NIST, PRL 98, 070801 (2007)
Berkeley, PRA 76, 062104 (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