Progress on testing Lorentz symmetry with MICROSCOPE

The Weak Equivalence Principle (WEP) and the local Lorentz invariance (LLI) are two major assumptions of General Relativity (GR). The MICROSCOPE mission, currently operating, will perform a test of the WEP with a precision of $10^{-15}$. The data will also be analysed at SYRTE for the purposes of a LLI test realised in collaboration with J. Tasson (Carleton College, Minnesota) and Q. Bailey (Embry-Riddle Aeronautical University, Arizona). This study will be performed in a general framework, called the Standard Model Extension (SME), describing Lorentz violations that could appear at Planck scale ($10^{19}$ GeV). The SME allows us to derive a Lorentz violating observable designed for the MICROSCOPE experiment and to search for possible deviations from LLI in the differential acceleration of the test masses

Prospects for SME Tests with Experiments at SYRTE and LKB

International audiencePreliminary work has been done in order to assess the perspectives of metrology and fundamental physics atomic experiments at SYRTE and LKB in the search for physics beyond the Standard Model and General Relativity. The first studies we identified are currently ongoing with the Microscope mission and with a Cs fountain clock. The latter brings significant improvement on the proton-sector coefficient down to the 10−17 GeV level

Prospects for SME Tests with Experiments at SYRTE and LKB

Preliminary work has been done in order to assess the perspectives of metrology and fundamental physics atomic experiments at SYRTE and LKB in the search for physics beyond the Standard Model and General Relativity. The first studies we identified are currently ongoing with the Microscope mission and with a Cs fountain clock. The latter brings significant improvement on the proton-sector coefficient cTT down to the 10−17 GeV level

Improved Tests of Lorentz Invariance in the Matter Sector Using Atomic Clocks

International audienceFor the purpose of searching for Lorentz-invariance violation in the minimal Standard-Model Extension, we perfom a reanalysis of data obtained from the 133Cs fountain clock operating at SYRTE. The previous study led to new limits on eight components of the μ v tensor, which quantifies the anisotropy of the proton’s kinetic energy. We recently derived an advanced model for the frequency shift of hyperfine Zeeman transition due to Lorentz violation and became able to constrain the ninth component, the isotropic coefficient, TT which is the least well-constrained coefficient of μ v. This model is based on a second-order boost Lorentz transformation from the laboratory frame to the Sun-centered frame, and it gives rise to an improvement of five orders of magnitude on TT and of one order of magnitude on Q compared to the state of the art

Improved Tests of Lorentz Invariance in the Matter Sector Using Atomic Clocks

For the purpose of searching for Lorentz-invariance violation in the minimal Standard-Model Extension, we perfom a reanalysis of data obtained from the 133Cs fountain clock operating at SYRTE. The previous study led to new limits on eight components of the ˜cµν tensor, which quantifies the anisotropy of the proton’s kinetic energy. We recently derived an advanced model for the frequency shift of hyperfine Zeeman transition due to Lorentz violation and became able to constrain the ninth component, the isotropic coefficient c˜TT, which is the least well-constrained coefficient of ˜cµν. This model is based on a second-order boost Lorentz transformation from the laboratory frame to the Sun-centered frame, and it gives rise to an improvement of five orders of magnitude on ˜cTT compared to the state of the art

Lorentz-symmetry test at Planck-scale suppression with nucleons in a spin-polarized 133^{133}Cs cold atom clock

International audienceWe introduce an improved model that links the frequency shift of the Cs133 hyperfine Zeeman transitions |F=3,mF⟩↔|F=4,mF⟩ to the Lorentz-violating Standard Model extension (SME) coefficients of the proton and neutron. The new model uses Lorentz transformations developed to second order in boost and additionally takes the nuclear structure into account, beyond the simple Schmidt model used previously in Standard Model extension analyses, thereby providing access to both proton and neutron SME coefficients including the isotropic coefficient c˜TT. Using this new model in a second analysis of the data delivered by the FO2 dual Cs/Rb fountain at Paris Observatory and previously analyzed in [1], we improve by up to 13 orders of magnitude the present maximum sensitivities for laboratory tests [2] on the c˜Q, c˜TJ, and c˜TT coefficients for the neutron and on the c˜Q coefficient for the proton, reaching respectively 10-20, 10-17, 10-13, and 10-15  GeV

LOW-ENERGY TESTS OF LORENTZ SYMMETRY: NEW CONSTRAINTS WITH NUCLEONS IN A COLD ATOM CLOCK

International audienceWe report on a Lorentz invariance test with nucleons in a cold atom 133 Cs clockusing spin-polarized states. We analyze this test in the Standard ModelExtension framework, and improve by up to 13 orders of magnitude the constraintson some coefficients parametrizing Lorentz violations

Lorentz-Symmetry Test at Planck-Scale Suppression With a Spin-Polarized 133^{133}Cs Cold Atom Clock

International audienceWe present the results of a local Lorentz invariance (LLI) test performed with the Cs-133 cold atom clock FO2, hosted at SYRTE. Such a test, relating the frequency shift between Cs-133 hyperfine Zeeman substates with the Lorentz violating coefficients of the standard model extension (SME), has already been realized by Wolf et al. and led to state-of-the-art constraints on several SME proton coefficients. In this second analysis, we used an improved model, based on a second-order Lorentz transformation and a self-consistent relativistic mean field nuclear model, which enables us to extend the scope of the analysis from purely proton to both proton and neutron coefficients. We have also become sensitive to the isotropic coefficient (c) over tilde TT, another SME coefficient that was not constrained by Wolf et al. The resulting limits on SME coefficients improve by up to 13 orders of magnitude the present maximal sensitivities for laboratory tests and reach the generally expected suppression scales at which signatures of Lorentz violation could appear

Lorentz-Symmetry Test at Planck-Scale Suppression with Nucleons in a Spin-Polarized 133 Cs Cold Atom Clock

The authors introduce an improved model that links the frequency of the 133 Cs hyperfine Zeeman transitions