Aharon Davidson

BLACK HOLES AS WINDOWS TO EXTRA DIMENSIONS

Abstract We derive the static three-dimensional spherically symmetric solution of the Einstein equations in an empty five-dimensional universe, and analyse the effective four-dimensional perspective. The radius of the compact fifth dimension is regarded as a local quantity. Our main conclusion is that the extra dimension becomes visible, and the associated Kaluza-Klein gauge interaction singular, when approaching the modified Schwarzschild horizon. The possibility of “massless” black holes is noted.

Elementary particles as higher-dimensional tachyons

Abstract Elementary particles are described as higher-dimensional tachyonic modes. Their electromagnetic inertial mass would not match the gravitational mass unless their scalar hypercharge vanishes. The corresponding unified geometry surrounding an elementary electric monopole is extracted. Remarkably, the ingoing five-dimensional geodetic lines, associated with like-sign charged test particles, cannot classically penetrate the finite three-dimensional spherical core on which the extra-dimensional circle shrinks to a point.

Zero cosmological constant from normalized general relativity

Normalizing the Einstein–Hilbert action by the volume functional makes the theory invariant under constant shifts in the Lagrangian. The associated field equations then resemble unimodular gravity whose otherwise arbitrary cosmological constant is now determined as a Machian universal average. We prove that an empty space-time is necessarily Ricci tensor flat, and demonstrate the vanishing of the cosmological constant within the scalar field paradigm. The cosmological analysis, carried out at the mini-superspace level, reveals a vanishing cosmological constant for a universe which cannot be closed as long as gravity is attractive. Finally, we give an example of a normalized theory of gravity which does give rise to a non-zero cosmological constant.

Finite magnetic flux tube as a black&white dihole

Abstract A finite-length magnetic vortex line solution is derived within the context of (4D) dilaton gravity. We approach the Bonnor metric at the Einstein-Maxwell limit, and encounter the “flux tube as (Euclidean) Kerr horizon” at the Kaluza-Klein level. Exclusively for string theory, the magnetic flux tube world-sheet exhibits a 2D black&white dihole structure.

Extensible Embeddings of Black-Hole Geometries

Imposing extendibility on Kasner-Fronsdal black hole local isometric embedding is equivalent to removing conic singularities in Kruskal representation. Allowing for globally non-trivial (living in

Abelian self-interaction of a test loop

M_{5}\times S_{1}

Quantized non-abelian wormholes

) embeddings, parameterized by

Quantum Black Hole Wave Packet: Average Area Entropy and Temperature Dependent Width

k

Normalized general relativity: Nonclosed universe and a zero cosmological constant

, extendibility can be achieved for apparently forbidden frequencies

Holographic Shell Model: Stack Data Structure inside Black Holes

\omega_{1}(k)\le\omega (k)\le \omega_{2}(k)