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Michael Edmund Tobar

Publications and source records attributed to Michael Edmund Tobar.

22 records · Page 2Linked to original sources

Erratum: New methods of testing Lorentz violation in electrodynamics

In an earlier paper [1] (hep-ph/0408006), the bound on the Standard Model Extension photon-sector parameter $\tildeκ_{tr}$ [2] (hep-ph/0205211) set by the heavy-ion storage-ring experiment of Saathoff et al. [3] was incorrectly reported. We show that the correct bound on $\tildeκ_{tr}$ which resulted from this experiment is in fact $2.2\times 10^{-7}$.

hep-ph↗

Global Representation of the Fine Structure Constant and its Variation

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 across all unit systems. Consequently, a variation in alpha was shown to manifest due to a differential change in the fraction of the quanta of electric and magnetic flux of force, while a variation in hcross.c was shown to manifest due to the common mode change. The representation is discussed with respect to the running of the fine structure constant at high energies (small distances), and a putative temporal drift. It is shown that the running of the fine structure constant is due to equal components of electric screening (polarization of vacuum) and magnetic anti-screening (magnetization of vacuum), which cause the perceived quanta of electric charge to increase at small distances, while the magnetic flux quanta decreases. This introduces the concept of the bare magnetic flux quanta as well as the bare electric charge. With regards to temporal drift, it is confirmed that it is impossible to determine which fundamental constant is varying if alpha varies.

hep-ph↗

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

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 Whispering Gallery Modes in a single sapphire resonator tuned to similar frequencies. When configured as a dual mode sapphire clock, we show that the anisotropy of sapphire makes it is possible to undertake a sensitive measurement from the beat frequency between the two modes. At infrared frequencies this is possible due to the different effect of the lowest phonon frequency on the two orthogonally polarized modes. At microwave frequencies we show that the phonon effect is too small. We show that the Electron Spin Resonance of paramagnetic impurities (such as Cr3+) in the lattice effects only one polarization with an alpha^6 dependence. This enables an enhancement of the sensitivity to temporal changes in a at microwave frequencies.

gr-qc↗

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

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 experiment allow: 1. Substantial common mode rejection of some noise sources: 2. Simple calculation of the signal if Special Relativity is violated. We show that optimum filtering may be used to increase the signal to noise ratio, and to search for a preferred direction of the speed of light. Using this technique we show that a sensitivity limit of order 7.10^-19 is possible by integrating data over one month. We propose methods to veto systematic effects by correlating the output of more than one experiment.

gr-qc↗