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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 43 (2002), S. 2423-2438 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Technical results are presented on motion in N(〉4)D manifolds to clarify the physics of brane theory, Kaluza–Klein theory, induced-matter theory, and string theory. The so-called canonical or warp metric in five dimensions (5D) effectively converts the manifold from a coordinate space to a momentum space, resulting in a new force (per unit mass) parallel to the four-dimensional (4D) velocity. The form of this extra force is actually independent of the form of the metric, but for an unbound particle is tiny because it is set by the energy density of the vacuum or cosmological constant. It can be related to a small change in the rest mass of a particle, and can be evaluated in two convenient gauges relevant to gravitational and quantum systems. In the quantum gauge, the extra force leads to Heisenberg's relation between increments in the position and momenta. If the 4D action is quantized then so is the higher-dimensional part, implying that particle mass is quantized, though only at a level of 10−65 g or less, which is unobservably small. It is noted that massive particles which move on timeline paths in 4D can move on null paths in 5D. This agrees with the view from inflationary quantum field theory, that particles acquire mass dynamically in 4D but are intrinsically massless. A general prescription for dynamics is outlined, wherein particles move on null paths in an N(〉4)D manifold which may be flat, but have masses set by an embedded 4D manifold which is curved. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 36 (1995), S. 6907-6914 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: When general relativity is extended from four to five dimensions, as in the theory of Kaluza and Klein, the relations for the classical tests are modified. The light-deflection problem shows a particularly interesting modification. We derive the general expression for light deflection by a massive body in the five-dimensional theory, and show that it can lead to significantly reduced deflection angles. © 1995 American Institute of Physics.
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 39 (1998), S. 2193-2200 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: In the modern version of 5-D general relativity where the fifth dimension induces matter in 4-D space–time, a choice of coordinates and its restrictions on the geometry (a gauge) dictates the physics of the gravitational, electromagnetic, and scalar fields (spin 2, 1, 0). We extend previous work by concentrating on two related problems. First, we use the lapse and shift formalism to carry out a (4+1) split of Kaluza–Klein theory valid in any gauge. Second, we use a conformal gauge to simplify the 5-D field equations, find a plane-wave solution, and identify the energy and momentum of the particle associated with it. © 1998 American Institute of Physics.
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 33 (1992), S. 3883-3887 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: Following earlier work, it is inquired how far the 5-D Kaluza–Klein equations without sources may be reduced to the Einstein equations with sources. It is shown by algebraic means that this can be done, provided the extra part of the 5-D geometry is used appropriately to define an effective 4-D energy-momentum tensor. The latter has reasonable properties, but will require further detailed study.
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 42 (2001), S. 5195-5201 
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: An exact class of solutions of the 5D vacuum Einstein field equations (EFEs) is obtained. The metric coefficients are found to be nonseparable functions of time and the extra coordinate l and the induced metric on l=const hypersurfaces has the form of a Friedmann–Robertson–Walker cosmology. The 5D manifold and 3D and 4D submanifolds are in general curved, which distinguishes this solution from previous ones in the literature. The singularity structure of the manifold is explored: some models in the class do not exhibit a big bang, while others exhibit a big bang and a big crunch. For the models with an initial singularity, the equation of state of the induced matter evolves from radiation-like at early epochs to Milne-like at late times and the big bang manifests itself as a singular hypersurface in 5D. The projection of comoving 5D null geodesics onto the 4D submanifold is shown to be compatible with standard 4D comoving trajectories, while the expansion of 5D null congruences is shown to be in line with conventional notions of the Hubble expansion. © 2001 American Institute of Physics.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 28 (1974), S. 289-302 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract When compact objects or black holes move through a fluid medium, or when turbulent plasma and magnetic fields so conspire, a gas flow is set up which closely resembles the flow of water down a plug-hole (Section 1). A similar hypothesis, but in reverse, was suggested by Jeans in 1928, and would nowadays be referred to as the white hole concept. The dynamics of the flow (Section 2) lead to expressions for the rotational velocity of the fluid far away from (2.1) and near to (2.2) the origin of the vorticity. Rotation curves derived from the model (Section 3) are closely akin to actual galactic rotation curves, but observational data on the latter are not precise enough to permit a delineation to be made between (i) flow around a singularity and (ii) flow around a non-singular sink or source. The other acceptable model, that of (iii) a spreading line vortex, is ruled out by comparison with astrophysical observations (Section 4). The basic analysis for all the models shows that the old problem of the winding-up of spiral arms can be avoided, since the galactic flow system is in a steady state. Section 5 identifies Jeans' speculation as being a hypothesis compatible with singular vortex flow and so with observation, but perhaps not with the usual interpretation of general relativity metrics, even though the requisite dual space does complete the topology in a mathematically satsifying manner. Section 6 concludes that the predictions of the hypothesis of vortex flow agree with the shape, dynamics and structure of galaxies.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 31 (1974), S. 333-339 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Clusters of galaxies are approximated by the Schwarzschild interior solution (with non-zero cosmological constant) embedded in a Robertson/Walker background. The conditions that the two metrics join up smoothly and that the cluster be stable imply either (a)k=−1 with Λ lying in the range −1.1×10−27≲Λ≲1.5×10−36 (s−2), or (b)k=0. Also, superclustering on a scale larger than 0.5 Mpc is unacceptable unless Λ〈0.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 32 (1975), S. 305-314 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Following the re-expression of the metric for a hierarchical cosmology in Section 1 (Introduction), the metric curvature is considered in Section 2 in showing that the hierarchy models are not, in general, related to the Robertson/Walker models even though the metrics can be made to appear superficially similar. The classes of models examined are quasi-Robertson/Walker models with Λ=0 (Section 3), quasi-Robertson/Walker models with Λ≠0 (Section 4), constant curvature (k(t)=constant) models (Section 5) and zero-curvature (k(t)=0) models (Section 6). The first group have ϱ0αt −3,S(t)αt 2 in a suitable limit; the second group have solutions expressible as incomplete elliptic integrals of the first and third kind; the next group (k(t)=const.) includes an oscillating model withϱ 0 (t)α[sin (t/2T)]−2,S(t)α[sin (t/2T)]2/3 and a model withk(t)αΛ(ϱ 0αt −2), and a model withk(t)αΛ −β 2/3(ϱ 0αe βt , β〈0); the last group comprises three models, one having Λ = 0(ϱ 0αt −2), one having Λ=−1/3T 2 where 2πT is the bounce period of the (oscillating) model, and an analogue of the de Sitter Universe with $$\varrho _0 (t)\alpha e^{ - \sqrt {3\Lambda t} } $$ and $$S(t)\alpha e^{ - \sqrt {(\Lambda /3)t} } $$ . Section 7 contains our conclusions.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 31 (1974), S. 341-347 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An approximate metric is found which represents a sphere of matter embedded in a background of dust. The use of this metric in conjunction with the Friedmann equations gives values of Λ for the three possible values ofk as Λ≃+6×10−36 (k=+1), Λ≃+3×10−35 (k=0), Λ≈+10−36 (k=−1). These values depend on data regarding clusters of galaxies, and are probably accurate to within an order of magnitude given the correctness of the assumptions on which their derivation rests.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 36 (1975), S. 363-382 
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Attention is given to the radiation of microwaves by charged dust in space. Presently-used particle distributions do not restrict the presence in space of large numbers of small (r〈10−6 cm) silicate grains, but it is shown that such densities (ϱ≈10−25–10−26 g cm−3) of small grains would produce a microwave background with an energy density of the same order of magnitude as the energy density of the (presumed) cosmological 3 K background. Limits set by the isotropy of the latter are: ϱ(HI clouds)≲10−26, ϱ(Galactic plane)≲10−30, ϱ(Halo)≲10−32, ϱ(Local Group)≲10−34 g cm−3. These limits imply that either there is a cutoff in particle distributions atr≃10−6 cm, or that the density of silicate grains in space has been generally overestimated, or that cosmic rays have broken up a lot of grains so that they now form a population of grains of very small size (≃10−7 cm) which are difficult to detect by conventional methods. One way to look for the latter population is by studying expected distortions of the 3 K spectrum to the short wavelength side of the portion hitherto observed (grains may have a size distribution able to give an approximate black-body curve for radiation from larger grains of 10−6 cm size), and by testing the effective energy density of the 3 K field in other galaxies.
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