17,429 research outputs found
Quanta Without Quantization
The dimensional properties of fields in classical general relativity lead to
a tangent tower structure which gives rise directly to quantum mechanical and
quantum field theory structures without quantization. We derive all of the
fundamental elements of quantum mechanics from the tangent tower structure,
including fundamental commutation relations, a Hilbert space of pure and mixed
states, measurable expectation values, Schroedinger time evolution, collapse of
a state and the probability interpretation. The most central elements of string
theory also follow, including an operator valued mode expansion like that in
string theory as well as the Virasoro algebra with central charges.Comment: 8 pages, Latex, Honorable Mention 1997 GRG Essa
Weyl gravity as general relativity
When the full connection of Weyl conformal gravity is varied instead of just
the metric, the resulting vacuum field equations reduce to the vacuum Einstein
equation, up to the choice of local units, if and only if the torsion vanishes.
This result differs strongly from the usual fourth-order formulation of Weyl
gravity.Comment: Final version, 11 pages. The role of torsion is clarified, two
appendices - on structure equations and Bianchi identities and on the basis
equation - have been adde
Normal Biconformal Spaces
A new 8-dimensional conformal gauging avoids the unphysical size change,
third order gravitational field equations, and auxiliary fields that prevent
taking the conformal group as a fundamental symmetry. We give the structure
equations, gauge transformations and intrinsic metric structure for the new
biconformal spaces. We prove that a torsion-free biconformal space with exact
Weyl form, closed dilational curvature and trace-free spacetime curvature
admits a sub-bundle of vanishing Weyl form homeomorphic to the Whitney sum
bundle of the tangent bundle and the bundle of orthonormal Lorentz frames over
4-dimensional spacetime. Conversely, any 4-dimensional spacetime extends
uniquely to such a normal biconformal space. The Einstein equation holds if and
only if the biconformal basis is orthonormal. Unconstrained antisymmetric trace
of the spacetime curvature provides a closed 2-form, independent of the Weyl
vector, consistently interpretable as the electromagnetic field. The trace of
the spacetime co-torsion decouples from gravitational sources and serves as
electromagnetic source.Comment: 32 pages, plain TeX, no figure
Extended Conformal Symmetry
We show that the grading of fields by conformal weight, when built into the
initial group symmetry, provides a discrete, non-central conformal extension of
any group containing dilatations. We find a faithful vector representation of
the extended conformal group and show that it has a scale-invariant scalar
product and satisfies a closed commutator algebra. The commutator algebra
contains the infinite Heisenberg and Virasoro algebras. In contrast to the
classical treatment of scale invariance, covariant derivatives and gauge
transformations automatically incorporate the correct conformal weights when
the extended symmetry is gauged.Comment: 15 page
Actions for Biconformal Matter
We extend 2n-dim biconformal gauge theory by including Lorentz-scalar matter
fields of arbitrary conformal weight. For a massless scalar field of conformal
weight zero in a torsion-free biconformal geometry, the solution is determined
by the Einstein equation on an n-dim submanifold, with the stress-energy tensor
of the scalar field as source. The matter field satisfies the n-dim
Klein-Gordon equation.Comment: 5 page
Time and dark matter from the conformal symmetries of Euclidean space
The quotient of the conformal group of Euclidean 4-space by its Weyl subgroup
results in a geometry possessing many of the properties of relativistic phase
space, including both a natural symplectic form and non-degenerate Killing
metric. We show that the general solution posesses orthogonal Lagrangian
submanifolds, with the induced metric and the spin connection on the
submanifolds necessarily Lorentzian, despite the Euclidean starting pont. By
examining the structure equations of the biconformal space in an orthonormal
frame adapted to its phase space properties, we also find that two new tensor
fields exist in this geometry, not present in Riemannian geometry. The first is
a combination of the Weyl vector with the scale factor on the metric, and
determines the timelike directions on the submanifolds. The second comes from
the components of the spin connection, symmetric with respect to the new
metric. Though this field comes from the spin connection it transforms
homogeneously. Finally, we show that in the absence of conformal curvature or
sources, the configuration space has geometric terms equivalent to a perfect
fluid and a cosmological constant.Comment: 26 pages, no figures. Appreciable introductory material added.
Results substantially strengthened and explained. New results concerning dark
matter and dark energy candidates added to this versio
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