An Optical Kennedy-Thorndike Experiment on the ISS (JULE) J. Nissen Jet Propulsion Laboratory, California Institute of Technology J.A. Lipa, Stanford University © All rights reserved.

An Optical Kennedy-Thorndike Experiment on the ISS (JULE) I IODINE V V KT = 7.7 km/s T KT = 91 min. Preferred Frame V CMB = 369 km/s RA DEC -7.22

 Considers only rods, clocks and light beams:  Assumes a ‘preferred’ inertial frame in which there are no Lorentz violations  Considers a moving frame in which violations can occur  If a laboratory is assumed to be moving at a velocity v relative to a preferred frame, the speed of light as a function of the angle  relative to the velocity vector is given by  c(  )/c = 1 + (1/2 -  +  )(v/c) 2 sin 2  + (  -  - 1) (v/c) 2 where  is the time dilation parameter,  is the length contraction parameter, and  tests for transverse contraction. (SR:  = -1/2;  = 1/2;  = 0)  Michelson-Morley measures c(sin 2   Kennedy-Thorndike measures c(v dv  - Mansouri and Sexl (1977) - Robertson (1949) Kinematic approach to Lorentz violations: 3

4 JULE

Lorentz violations in the Standard Model Extension (SME): “The natural scale for a fundamental theory including gravity is governed by the Planck mass MP, which is about 17 orders of magnitude greater than the electroweak scale mW associated with the standard model. This suggests that observable experimental signals from a fundamental theory might be expected to be suppressed by some power of the ratio: r ≈ mW ⁄ MP ~ ” Colladay and Kostelecky Phys. Rev. D 58, (1998).

Recent Results from MM Type Experiments Ch. Eisele, A.Yu. Nevsky, and S. Schiller PRL 103, (2009) M. A. Hohensee et al arXiv: v1 [hep-ph] 7 Jun 2010

 A general Lorentz-violating extension of the Standard Model was  developed by Colladay and Kostelecky in  It covers potential violations for photons, fermions and bosonic  components of matter  Because of its general nature, it contains many (>120) parameters  This results in a wide variety of interesting experiments, from light  polarization studies of quasars to cavity and atomic clock experiments  to analyses of high energy particle experiments at Cern and Fermilab  Any violation observed would be considered a clue to understanding  Planck-scale physics and the details of the Big Bang Lorentz violations in extensions of the Standard Model: 7

Collaborators/Roles: NASA Centers: JPL, possibly Ames: Build, ATLO, technology tests. Industry: Instrument build? Academia: Stanford University: Science data analysis, test evaluation, mission ops support; possible JILA consulting. International: Potential partnerships with Germany (DLR), France (ACES). Value to Agency: Aligned with Astrophysics Division objectives: “ Test the validity of Einstein ’ s General Theory of Relativity ”. “ Investigate the nature of space-time through tests of fundamental symmetries ” ; (e.g., is the speed of light truly a constant?). A null result constrains theories attempting to unify gravity and quantum physics: Nobel quality research if a signal is detected. Advanced clock technology development. Rationale for ISS accommodations: Measurements are a factor of ~ 80 more sensitive in low earth orbit than on Earth’s surface. ISS eases power and data handling relative to a free flier. Link to ACES in European ISS module could enhance science. A Kennedy-Thorndike Experiment on the ISS Justification: 8

Description and Objectives: Technical description: JULE compares the time dilation of a clock with the length contraction of a cavity aboard the ISS. The clock is based on an atomic transition in Iodine (Jod), the length reference is based on the resonance of an optical cavity made from ultra-low expansion glass (ULE). Einstein’s theory of relativity predicts a null result. JULE is a modern version of the Kennedy-Thorndike experiment, complimenting recent Michelson-Morley type experiments. Physical Description: Payload internal (preferred) or external to the ISS; power ~ 100 W; mass ~ 70 kg; vol ~ 50 cm cube; data rate ~ 2 kB/sec. Optical cavity axis needs to be aligned with the ram direction to ~1°. Short list of objectives: Measure frequency difference to ~ 1 part in vs. position around orbit. Measure frequency difference to ~ 1 part in vs. gravitational potential. Technology Readiness/Implementation approach: components at TRL 4+. A Kennedy-Thorndike Experiment on the ISS 9

ULE cavity developed for GRACE-II laser stabilization (JPL/Ball Aerospace) 10

Iodine setup developed for LISA- Leonhardt (2006) 11

Optimum Clock Performance

Results and projections for Iodine molecular clock 13

ACES to JULE via frequency comb: 14

STAR 1 spacecraft concept 15

16 STAR- Space Tests of Anisotropy Research

Other space Lorentz invariance experiments: 17 ACES/PHARAO- ESA, 1990? flight hardware development SUMO- NASA, 1994, mothballed OPTIS- ESA, 2000, phase A study PARCS/SUMO- NASA, 2003 mothballed Opto-SUMO- 2006, concept STAR- NASA/KACST/DLR, 2007, pre-phase A development Einstein Gravity Explorer- ESA, 2007, proposed SOC- ESA, 2007, pre-phase A study

ISS FP Workshop Charter Develop a set of written recommendations for NASA regarding NASA’s and partnering agencies ISS research activities describing: 1.What the scientific role of NASA/U.S. scientists should be in future planned ESA ISS research projects in optical atomic clocks, atom interferometers, or BEC to be solicited in FY11 NRA. [Scientific collaboration], {$} 2.What the hardware role of NASA should be in future planned ESA ISS research projects in atomic clocks, atom interferometers, or BEC in space. [Scientific and Technical collaboration], {$$} Optical Etalon for Kennedy-Thorndike Experiment. 3.What the scientific role of NASA/U.S. scientists should be in future CNES DECLIC condensed matter physics projects. [Scientific collaboration], {$} 4.What the hardware role of NASA should be in future CNES/ESA DECLIC projects in condensed matter physics. [Scientific and technical collaboration], {$$} 5.What the hardware role of NASA should be in a collaboration with JAXA on fundamental physics ISS research projects utilizing the LTMPF. [Scientific and Technical collaboration], {$$$} Cold Optical Etalon? MM Experiment? 6.What the scientific and hardware role of NASA/U.S. scientists should be in future ISS research projects in fundamental physics, including optical atomic clocks, atom interferometers, BEC, General Relativity, physics beyond the standard model, and condensed matter physics. [Scientific and Technical collaboration], {$$$} Lorentz Invariance Experiments.