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Browsing Physics publications by Author "2008 IEEE International Frequency Control Symposium (19 May 2008 - 21 May 2008 : Honolulu, HI)"

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    Continuous operation of an odd parity Lorentz Invariance test in electrodynamics using a microwave interferometer
    (IEEE, 2008) Tobar, M.E.; Ivanov, E.N.; Stanwix, P.L.; le Floch, J.M.; Hartnett, J.G.; 2008 IEEE International Frequency Control Symposium (19 May 2008 - 21 May 2008 : Honolulu, HI)
    We present results from an odd parity test of Lorentz invariance in electrodynamics, based on a rotating microwave interferometer with permeable material in one arm. The experiment has been operating continuously since September 2007. Results set a limit on the standard model extension (SME) scalar Lorentz violating parameter, kappa(tr), of -0.8plusmn3.6times10⁻⁷.
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    Development of synthesis chains based on a cryogenic sapphire oscillator
    (IEEE, 2008) Kumagai, M.; Ito, H.; Hosokawa, M.; Santarelli, G.; Locke, C.R.; Hartnett, J.G.; 2008 IEEE International Frequency Control Symposium (19 May 2008 - 21 May 2008 : Honolulu, HI)
    We have developed a 1 GHz synthesis chain based on a cryogenic sapphire oscillator. The 11.2005 GHz output of the CSO is down-converted for laboratory distribution. The frequency stability of the down-converter itself is 2times10⁻¹⁵ at an averaging time of 1 second. The long-term drift of the CSO is suppressed by referencing it to a hydrogen maser linked to Japan Standard Time. An application of this highly stable reference is absolute frequency measurement of an ultra-narrow clock laser for the optical frequency standard performed using a frequency comb, in which the repetition rate is stabilized by the CSO signal.