568 research outputs found
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.Comment: Final accepted version for Metrologia. This version includes a proof
that the representation of the fine structure constant is global across all
unit systems, using Jackson's global representation of Maxwell's equations
(which is also valid for all unit systems). The version is shorter than the
previous, thus the discussion throughout is more brie
Gravitational Wave Detection and Low-Noise Sapphire Oscillators
This thesis describes the development of an ultra-low noise sapphire
resonator oscillator that is tunable over X-band. While undertaking this task
the author has explained some interesting and very useful phenomena in regards
to the design and understanding of multi-mode resonant cavities and
oscillators. The oscillator was constructed to operate as the pump oscillator
in the superconducting parametric transducer system, attached to a 1.5-tonne
niobium resonant bar gravitational wave detector. The effects of incorporating
the pump oscillator with the parametric transducer and resonant bar system are
analyzed to enable prediction of the detector sensitivity. The detector was the
first massive precision optomechanical system ever built. With the resurgence
in interest in resonant detectors, this thesis has important work on multi-mode
acoustic systems, coupled to a highly sensitive parametric transducer relevant
for many fields of research today.Comment: PhD Thesis, University of Western Australi
Testing Local Lorentz and Position Invariance and Variation of Fundamental Constants by searching the Derivative of the Comparison Frequency Between a Cryogenic Sapphire Oscillator and Hydrogen Maser
The cryogenic sapphire oscillator (CSO) at the Paris Observatory has been
continuously compared to various Hydrogen Masers since 2001. The early data
sets were used to test Local Lorentz Invariance in the Robertson-Mansouri-Sexl
(RMS) framework by searching for sidereal modulations with respect to the
Cosmic Microwave Background, and represent the best Kennedy-Thorndike
experiment to date. In this work we present continuous operation over a period
of greater than six years from September 2002 to December 2008 and present a
more precise way to analyze the data by searching the time derivative of the
comparison frequency. Due to the long-term operation we are able to search both
sidereal and annual modulations. The results gives P_{KT} =
\beta_{RMS}-\alpha_{RMS}-1 = -1.7(4.0) \times 10^{-8} for the sidereal and
-23(10) \times 10^{-8} for the annual term, with a weighted mean of -4.8(3.7)
\times 10^{-8}, a factor of 8 better than previous. Also, we analyze the data
with respect to a change in gravitational potential for both diurnal and annual
variations. The result gives \beta_{H-Maser} - \beta_{CSO} = -2.7(1.4) \times
10^{-4} for the annual and -6.9(4.0) \times 10^{-4} for the diurnal terms, with
a weighted mean of -3.2(1.3) \times 10^{-4}. This result is two orders of
magnitude better than other tests that use electromagnetic resonators. With
respect to fundamental constants a limit can be provided on the variation with
ambient gravitational potential and boost of a combination of the fine
structure constant (\alpha), the normalized quark mass (m_q), and the electron
to proton mass ratio (m_e/m_p), setting the first limit on boost dependence of
order 10^{-10}.Comment: Fixed typo
Creating traveling waves from standing waves from the gyrotropic paramagnetic properties of Fe ions in a high-Q whispering gallery mode sapphire resonator
We report observations of the gyrotropic change in magnetic susceptibility of
the Fe electron paramagnetic resonance at 12.037GHz (between spin states
and ) in sapphire with respect to applied magnetic field.
Measurements were made by observing the response of the high-Q Whispering
Gallery doublet (WGH) in a Hemex sapphire resonator cooled to 5
K. The doublets initially existed as standing waves at zero field and were
transformed to traveling waves due to the gyrotropic response.Comment: Accepted for publication in Phys. Rev.
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