A New interpretation of MOND based on Mach principle and an Unruh like effect

A new interpretation is introduced for MOND based on the Sciama's interpretation of Mach principle and an Unruh like effect, in the context of a generalized equivalence principle. It is argued that in a locally accelerated frame with acceleration $a$ the appearance of a Rindler horizon may give rise to a constant acceleration $a_0$ as the local properties of cosmological horizon or Hubble length. The total gravitational acceleration inside this frame becomes the combination of $a$ with $a_0$. For $a\gg a_0$, the conventional gravitational mass $m_g$ interacts with the dominant acceleration as $m_g a$ and application of Sciama's interpretation leads to the standard Newtonian dynamics. For $a\ll a_0$, however, a reduced gravitational mass $\bar{m}_g$ interacts with the dominant acceleration as $\bar{m}_g a_0$ and the application of Sciama's interpretation on this reduced gravitational mass leads to MOND. This introduces a third proposal for MOND: {\it The modification of gravitational mass}.Comment: 11 pages, throughout revisio

A Note on the Integral Formulation of Einstein's Equations Induced on a Braneworld

We revisit the integral formulation (or Green's function approach) of Einstein's equations in the context of braneworlds. The integral formulation has been proposed independently by several authors in the past, based on the assumption that it is possible to give a reinterpretation of the local metric field in curved spacetimes as an integral expression involving sources and boundary conditions. This allows one to separate source-generated and source-free contributions to the metric field. As a consequence, an exact meaning to Mach's Principle can be achieved in the sense that only source-generated (matter fields) contributions to the metric are allowed for; universes which do not obey this condition would be non-Machian. In this paper, we revisit this idea concentrating on a Randall-Sundrum-type model with a non-trivial cosmology on the brane. We argue that the role of the surface term (the source-free contribution) in the braneworld scenario may be quite subtler than in the 4D formulation. This may pose, for instance, an interesting issue to the cosmological constant problem.Comment: 10 pages, no figures, accepted for publication in the General Relativity and Gravitation Journa

An assessment of Evans' unified field theory II

Evans developed a classical unified field theory of gravitation and electromagnetism on the background of a spacetime obeying a Riemann-Cartan geometry. In an accompanying paper I, we analyzed this theory and summarized it in nine equations. We now propose a variational principle for Evans' theory and show that it yields two field equations. The second field equation is algebraic in the torsion and we can resolve it with respect to the torsion. It turns out that for all physical cases the torsion vanishes and the first field equation, together with Evans' unified field theory, collapses to an ordinary Einstein equation.Comment: 11 pages of late

The power spectrum of the circular noise

The circular noise is important in connection to Mach's principle, and also as a possible probe of the Unruh effect. In this letter the power spectrum of the detector following the Trocheries-Takeno motion in the Minkowski vacuum is analytically obtained in the form of an infinite series. A mean distribution function and corresponding energy density are obtained for this particular detected noise. The analogous of a non constant temperature distribution is obtained. And in the end, a brief discussion about the equilibrium configuration is given.Comment: accepted for publication in GR

On the Machian Origin of Inertia

We examine Sciama's inertia theory: we generalise it, by combining rotation and expansion in one unique model, we find the angular speed of the Universe, and we stress that the theory is zero-total-energy valued. We compare with other theories of the same null energy background. We determine the numerical value of a constant which appears in the Machian inertial force expression devised by Graneau and Graneau[2], by introducing the above angular speed. We point out that this last theory is not restricted to Newtonian physics as those authors stated but is, in fact, compatible with other cosmological and gravitational theories. An argument by Berry[7] is shown in order to "derive" Brans-Dicke relation in the present context.Comment: 10 pages including front one. New version was accepted to publication by Astrophysics and Space Scienc

Sonoluminescence: Two-photon correlations as a test of thermality

In this Letter we propose a fundamental test for probing the thermal nature of the spectrum emitted by sonoluminescence. We show that two-photon correlations can in principle discriminate between real thermal light and the quasi-thermal squeezed-state photons typical of models based on the dynamic Casimir effect. Two-photon correlations provide a powerful experimental test for various classes of sonoluminescence models.Comment: 6 pages, revtex 3; revised to include more discussion of finite volume effects; physics conclusions unchanged; to appear in Physics Letters

'Universal' FitzGerald Contractions

The model of a universe with a preferred frame, which nevertheless shares the main properties with traditional special and general relativity theories, is considered. We adopt Mach's interpretation of inertia and show that the energy balance equation, which includes the Machian energy of gravitational interactions with the universe, can imitate standard relativistic formulas.Comment: The version accepted by Eur. Phys. J.

Four-fermion interaction from torsion as dark energy

The observed small, positive cosmological constant may originate from a four-fermion interaction generated by the spin-torsion coupling in the Einstein-Cartan-Sciama-Kibble gravity if the fermions are condensing. In particular, such a condensation occurs for quark fields during the quark-gluon/hadron phase transition in the early Universe. We study how the torsion-induced four-fermion interaction is affected by adding two terms to the Dirac Lagrangian density: the parity-violating pseudoscalar density dual to the curvature tensor and a spinor-bilinear scalar density which measures the nonminimal coupling of fermions to torsion.Comment: 6 pages; published versio

On the gravitodynamics of moving bodies

In the present work we propose a generalization of Newton's gravitational theory from the original works of Heaviside and Sciama, that takes into account both approaches, and accomplishes the same result in a simpler way than the standard cosmological approach. The established formulation describes the local gravitational field related to the observables and effectively implements the Mach's principle in a quantitative form that retakes Dirac's large number hypothesis. As a consequence of the equivalence principle and the application of this formulation to the observable universe, we obtain, as an immediate result, a value of Omega = 2. We construct a dynamic model for a galaxy without dark matter, which fits well with recent observational data, in terms of a variable effective inertial mass that reflects the present dynamic state of the universe and that replicates from first principles, the phenomenology proposed in MOND. The remarkable aspect of these results is the connection of the effect dubbed dark matter with the dark energy field, which makes it possible for us to interpret it as longitudinal gravitational waves.Comment: 18 pages, 4 figures. Final version: almost identical to the reference journal; Cent. Eur. J. Phys. 201

Thermodynamic Gravity and the Schrodinger Equation

We adopt a 'thermodynamical' formulation of Mach's principle that the rest mass of a particle in the Universe is a measure of its long-range collective interactions with all other particles inside the horizon. We consider all particles in the Universe as a 'gravitationally entangled' statistical ensemble and apply the approach of classical statistical mechanics to it. It is shown that both the Schrodinger equation and the Planck constant can be derived within this Machian model of the universe. The appearance of probabilities, complex wave functions, and quantization conditions is related to the discreetness and finiteness of the Machian ensemble.Comment: Minor corrections, the version accepted by Int. J. Theor. Phy