Lorentz invariance violations: Kostelecky, 2002

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2 Lorentz invariance violations: Kostelecky,

3 Kinematic approach to Lorentz invariance violations: Considers only light beams and ideal rods, clocks: 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 θ relative to the velocity vector is given by c(θ)/c = 1 + (1/2 - β + δ)(v/c) 2 sin 2 θ + (β - α - 1) (v/c) 2 where α is the time dilation parameter, β is the Lorentz contraction parameter, and δ tests for transverse contraction. (SR: α = -1/2; β = 1/2; δ = 0) Michelson-Morley : θ-dependent term Kennedy-Thorndike : θ-independent term - Mansouri and Sexl (1977) Simple but incomplete! 3

4 Lorentz violations in extensions to the Standard Model: Subset of Lorentz and CPT violating Standard Model Extension (SME) - Colladay and Kostelecky Considers small violations that are potential remnants of Planck-scale physics - subset considers Lorentz-violating quantum electrodynamics - restricting to photon sector and renormalizable terms - reduces to Maxwell equations plus two Lorentz-violating terms: - one term CPT-odd(breaking), the other CPT-even(preserving) - CPT-odd term known to be very small from radio galaxy polarization data - CPT-even term less well-known Model has analogy with electrodynamics in a homogeneous anisotropic medium - has links to Mansouri and Sexl kinematics, and relates to THεµ -19 free parameters, 10 constrained by astrophysical observations - Optical cavities sensitive to other 9 parameters - Kostelecky and Mewes, 2002 Extended: Kostelecky and Mewes,

5 MM and KT as subsets of the SME: highly simplified example (K&M 2009): rods and clocks have effective metrics with Lorentz violating parameters: c clock, c rod obtain β + δ -1/2 = 7/12(c rod ) 00 (MM style) α - β +1 = - 7/12(c rod ) 00-5/12 (c clock ) 00 (KT style) => KT measurements dont reduce to MM measurements except in special cases => MM and KT relate to the fermion sector (?) 5

6 Lorentz violations may involve species-dependent fields: (experiments need to specify species involved) 6

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9 First modern Michelson-Morley expt: Brillet and Hall, PRL

10 Crossed-cavity MM experiment: Peters,

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12 Sun-synchronous orbital motion of STAR instruments: Sun Earth 12

13 Lorentz Symmetry & Lorentz Violations: STAR: Search for a Lorentz violations at the level of to A factor of 100 to 300 better than ground experiments Both orientation & velocity dependent violations LORENTZ SYMMETRY & LORENTZ VIOLATIONS Time dilation: equally boosted clocks tick at different rates Length contraction: rods have angle and boost dependent lengths Lorentz violations may exist independent of a universal preferred reference frame 13

14 Why KT in Space? Kennedy-Thorndike signal enhancement Signal modulated at satellite orbital variation ~1.5 hr Signal modulated at orbital velocity differences ±7 km/s Diurnal Earth rotation signal < hr Yearly Earth orbital motion signal at hr Disturbance reduction Microgravity Seismic quietness Relaxed stress due to self weight Far away from time dependent gravity gradient noises KT Improvement in Space: Faster signal modulation 4 ( 16) Higher velocity modulation 20 to 30 Other considerations ~ 1 to 3 Net Overall Advantage

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23 STAR iodine setup: 23

24 STAR conceptual diagram: 24

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26 Thermal modeling of enclosure: 26

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29 STAR mission characteristics: ESPA compatible secondary payload on an EELV launch Circular sun-synchronous ~ 650 km orbit Launch year mission lifetime 29

30 Vibration insensitive optical cavities: STRAIN DISTRIBUTION Zero relative displacement at the ends of the optics axis Static Load applied at the points marked on the perimeter 30

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34 Atomic references for KT-style tests: nominally isotropic systems: I 2, CO, C 2 H 2 etc very narrow linewidths -> excellent frequency stability relaxed environmental control relative to cavities access various LIV coefficients in fermion sector technical issue is making a beat note between two systems Femtosecond frequency combs could bridge the gap - But to fly a frequency comb on a satellite is still a challenge.. 34

35 STAR Collaboration: Collaborating Institutions Main Contributions ALL Science and EP&O Ames Research Center PM, SE, I&T, and SM&A KACST Spacecraft and Launch Stanford University PI and Instruments to TRL 4 German Space Agency et al Instruments, Flight Clock JILA Instruments to TRL 4 Industrial Partner Flight Instrument Germany German Aerospace Center (DLR) ZARM & Bremen University Humboldt University, Berlin University of Konstanz Kingdom of Saudi Arabia King Abdulaziz City for Science and Technology (KACST) United States NASA Ames Research Center (ARC) Stanford University Joint Institute for Laboratory Astrophysics (JILA) University of California-Davis Industrial partner 35