69 research outputs found
Supernovae data: Cosmological Constant or ruling out the Cosmological Principle ?
Analysed in the framework of homogeneous FLRW models, the magnitude-redshift
data from high redshift supernovae yield, as a primary result, a strictly
positive cosmological constant. Another reading of the currently published
measurements does not exclude a possible ruling out of the Cosmological
Principle and, thus, also, of the cosmological constant hypothesis. It is shown
how shortly coming data can be used to settle this fondamental issue,
pertaining to both cosmology and particle physics.Comment: 4 LaTex pages, to be published in the Proceedings of COSMO-99,
International Workshop on Particle Physics and the Early Universe, World
Scientific, 200
Electromagnetic Klein-Gordon and Dirac equations in scale relativity
We present a new step in the foundation of quantum field theory with the
tools of scale relativity. Previously, quantum motion equations (Schr\"odinger,
Klein-Gordon, Dirac, Pauli) have been derived as geodesic equations written
with a quantum-covariant derivative operator. Then, the nature of gauge
transformations, of gauge fields and of conserved charges have been given a
geometric meaning in terms of a scale-covariant derivative tool. Finally, the
electromagnetic Klein-Gordon equation has been recovered with a covariant
derivative constructed by combining the quantum-covariant velocity operator and
the scale-covariant derivative. We show here that if one tries to derive the
electromagnetic Dirac equation from the Klein-Gordon one as for the free
particle motion, i.e. as a square root of the time part of the Klein-Gordon
operator, one obtains an additional term which is the relativistic analog of
the spin-magnetic field coupling term of the Pauli equation. However, if one
first applies the quantum covariance, then implements the scale covariance
through the scale-covariant derivative, one obtains the electromagnetic Dirac
equation in its usual form. This method can also be applied successfully to the
derivation of the electromagnetic Klein-Gordon equation. This suggests it rests
on more profound roots of the theory, since it encompasses naturally the
spin-charge coupling.Comment: 14 pages, no figure
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