Michael Edmund Tobar

Creating traveling waves from standing waves from the gyrotropic paramagnetic properties of Fe$^{3+}$ ions in a high-Q whispering gallery mode sapphire resonator (2009)

Benmessai, Karim, Tobar, Michael Edmund, Bazin, Nicholas, Bourgeois, Pierre-Yves, Kersale, Yann, Giordano, Vincent

We report observations of the gyrotropic change in magnetic susceptibility of the Fe$^{3+}$ electron paramagnetic resonance at 12.037GHz (between spin states $|1/2>$ and $|3/2>$) in sapphire with...

Microwave Phase Detection at the Level of $10^{-11}$ rad (2009)

Ivanov, Eugene Nicolay, Tobar, Michael Edmund

We report on a noise measurement system with the highest spectral resolution ever achieved in the microwave domain. It is capable of detecting the phase fluctuations of $rms$ amplitude of...

Detecting Free-Mass Common-Mode Motion Induced by Incident Gravitational Waves: Testing General Relativity and Source Direction via Fox-Smith and Michelson Interferometers (2009)

Tobar, Michael Edmund, Suzuki, Toshikazu, Kuroda, Kazuaki

In this paper we show that information on both the differential and common mode free-mass response to a gravitational wave can provide important information on discriminating the direction of the...

Measurement of fundamental thermal noise limit in a cryogenic sapphire frequency standard using bimodal maser oscillations (2008)

Benmessai, Karim, Creedon, Daniel Lloyd, Tobar, Michael Edmund, Bourgeois, Pierre-Yves, Kersale, Yann, Giordano, Vincent

We report observations of the Schawlow-Townes noise limit in a cryogenic sapphire secondary frequency standard. The effect causes a fundamental limit to the frequency stability, and was measured...

Relativity tests by complementary rotating Michelson-Morley experiments (2007)

Mueller, Holger, Stanwix, Paul Louis, Tobar, Michael Edmund, Ivanov, Eugene, Wolf, Peter, Herrmann, Sven, ...

We report Relativity tests based on data from two simultaneous Michelson-Morley experiments, spanning a period of more than one year. Both were actively rotated on turntables. One (in Berlin,...

Erratum: New methods of testing Lorentz violation in electrodynamics (2007)

Hohensee, Michael, Glenday, Alex, Li, Chih-Hao, Tobar, Michael Edmund, Wolf, Peter

In an earlier paper [1] (hep-ph/0408006), the bound on the Standard Model Extension photon-sector parameter $\tilde{\kappa}_{tr}$ [2] (hep-ph/0205211) set by the heavy-ion storage-ring experiment of...

Global Representation of the Fine Structure Constant and its Variation (2003)

Tobar, Michael Edmund

The fine structure constant, alpha, is shown to be proportional to the ratio of the quanta of electric and magnetic flux of force of the electron, and provides a new representation, which is global...

Proposal for a New Test of the Time Independence Of The Fine Structure Constant, alpha, Using Orthogonally Polarised Whispering Gallery Modes in a Single Sapphire Resonator (2003)

Tobar, Michael Edmund, Hartnett, John Gideon

A new experiment to test for the time independence of the fine structure constant, alpha, is proposed. The experiment utilizes orthogonally polarized Transverse Electric and Transverse Magnetic...

Proposal for a New Michelson-Morley Experiment Using a Single Whispering Spherical Mode Resonator (2002)

Tobar, Michael Edmund, Hartnett, John Gideon, Anstie, James David

A new Michelson-Morley experiment is proposed by measuring the beat frequency of two near degenerate modes with orthogonal propagation in a single spherical resonator. The unique properties of the...