The retrieved physics literature and historical texts discuss gravitational vacuum solutions, vacuum energy, and the theoretical transmission of gravitational force through a vacuum.
In quantum gravity perturbation theory in Newton's constant $G$ is known to be badly divergent, and as a result not very useful. Nevertheless, some of the most interesting phenomena in physics are often associated with non-analytic behavior in the coupling constant and the existence of nontrivial quantum condensates. It is therefore possible that pathologies encountered in the case of gravity are more likely the result of inadequate analytical treatment, and not necessarily a reflection of some intrinsic insurmountable problem. The nonperturbative treatment of quantum gravity via the Regge-Wheeler lattice path integral formulation reveals the existence of a new phase involving a nontrivial gravitational vacuum condensate, and a new set of scaling exponents characterizing both the running of $G$ and the long-distance behavior of invariant correlation functions. The appearance of such a gravitational condensate is viewed as analogous to the (equally nonperturbative) gluon and chiral condensates known to describe the physical vacuum of QCD. The resulting quantum theory of gravity is highly constrained, and its physical predictions are found to depend only on one adjustable parameter, a genuinely nonperturbative scale $\xi$ in many ways analogous to the scaling violation parameter $\Lambda_{\bar MS} $ of QCD. Recent results point to significant deviations from classical gravity on distance scales approaching the effective infrared cutoff set by the observed cosmological constant. Such subtle quantum effects are expected to be initially small on current cosmological scales, but could become detectable in future high precision satellite experiments.
According to general relativity, black holes are incomplete, which prevents developing a complete physical description of their dynamical formation and evolution once quantum effects are taken into account. Theories beyond general relativity may provide a more complete description of black hole interiors. In this work, the most general form of the field equations for spherically symmetric gravitational fields, in which the Einstein tensor is deformed into a conserved tensor constructed from up to second-order derivatives of the metric, is described. These equations set up the stage for the study of the dynamics of spherically symmetric spacetimes beyond general relativity, providing tools for the theoretical exploration of a paradigm of black hole physics free of the incompleteness characteristic of Einstein's theory. A general proof of the Birkhoff-Jebsen theorem for vacuum solutions, and the construction of field equations describing the effective geometrodynamics of regular black holes interacting with matter, are discussed.
The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions. The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature. The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on ‘Black holes, Gravitational waves and Fundamental Physics’.
Contrary to the situation which holds for the canonical theory described in the first paper of this series, there exists at present no tractable pure operator language on which to base a manifestly covariant quantum theory of gravity. One must construct the theory by analogy with conventional S-matrix theory, using the c-number language of Feynman amplitudes when nothing else is available. The present paper undertakes this construction. It begins at an elementary level with a treatment of the propagation of small disturbances on a classical background. The classical background plays a fundamental role throughout, both as a technical instrument for probing the vacuum (i.e., analyzing virtual processes) and as an arbitrary fiducial point for the quantum fluctuations. The problem of the quantized light cone is discussed in a preliminary way, and the formal structure of the invariance group is displayed. A condensed notation is adopted which permits the Yang-Mills field to be studied simultaneously with the gravitational field. Generally covariant Green's functions are introduced through the imposition of covariant supplementary conditions on small disturbances. The transition from the classical to the quantum theory is made via the Poisson bracket of Peierls. Commutation relations for the asymptotic fields are obtained and used to define the incoming and outgoing states. Because of the non-Abelian character of the coordinate transformation group, the separation of propagated dis
`Mass without mass' from thin shells in Gauss-Bonnet gravity
Five tensor equations are obtained for a thin shell in Gauss-Bonnet gravity. There is the well known junction condition for the singular part of the stress tensor intrinsic to the shell, which we also prove to be well defined. There are also equations relating the geometry of the shell (jump and average of the extrinsic curvature as well as the intrinsic curvature) to the non-singular components of the bulk stress tensor on the sides of the thin shell. The equations are applied to spherically symmetric thin shells in vacuum. The shells are part of the vacuum, they carry no energy tensor. We classify these solutions of `thin shells of nothingness' in the pure Gauss-Bonnet theory. There are three types of solutions, with one, zero or two asymptotic regions respectively. The third kind of solution are wormholes. Although vacuum solutions, they have the appearance of mass in the asymptotic regions. It is striking that in this theory, exotic matter is not needed in order for wormholes to exist- they can exist even with no matter.
For thousands of years science assumed that the natural force known as gravity was an attraction force. In a previous article it was shown that gravity is a repulsion force rather than an attraction one. This new outlook on gravity explained why the Relativity theory claiming relativistic length contraction and time dilation is undecidable. In a previous article it is explained that repulsion gravity exists everywhere [1]. I. e. there is no perfect vacuum anywhere in the universe. Because of this fact, the massless photon is forced to find a path of least resistance and surely cannot be proven to dilate time or contract lengths. The repulsion nature of gravity suggests it is possible to use its repulsion force to overcome gravity by generating a rotation of a rotating object. This article explains how this is likely achievable. The article also shows that likely gravity may be controlled by simulating gravity with 3-dimensional rotation defined in this article.
Abstract In order to search for new solutions for collapsed objects in quantum gravity, we consider in this paper a Kantowski–Sachs metric labelled by parameters that have no classical significance. In addition, we include a Klein–Gordon field to represent in a simple manner the inevitable zero-point vacuum fluctuations that permeate the spacetime. With this framework, we quantize the system and obtain the Wheeler–DeWitt equation in order to focus upon the deep quantum regime of the interior and to analyze any kind of transition that the black hole may undergo. The Wheeler–DeWitt equation reveals the existence of new solutions of different nature, designated herein as “quantum grey holes,” in addition to the existence of quantum black holes, with all solutions satisfying the DeWitt boundary condition. The existence of new solutions gives rise to the novel possibility of a quantum black hole making a transition to a quantum grey hole. We find that there exists non-zero probability of quantum black-to-grey hole transition. These transition probabilities exhibit resonances for a continuous range of eigenvalues of the system.
On Action at a Distance (Browne) ← On Action at a Distance by Walter Raleigh Browne → sister projects : Wikidata item Browne, Walter Raleigh (1881), " On Action at a Distance ", Proceedings of the Physical Society of London , 4 : 71-81 , < http://books.google.com/books?id=9-AEAAAAQAAJ > . 264373 On Action at a Distance Walter Raleigh Browne Read November 13, 1880 THE object of this paper is partly historical, partly critical. In discussing what is called "Action at a Distance," the statement is frequently made that Newton was of opinion that " nobody who possessed a competent faculty of thinking" could possibly imagine such a thing to exist. The writer wishes, first, to show historically that this is by no means an accurate representation of Newton-s views, and, secondly, to consider critically whether the repudiation of " action at a distance," which is now certainly common, is, after all, justified by the facts of the universe. In the first place, Newton's words, contained in the Third Letter to Bentley, are as follows :—" That gravity should be innate, inherent, and essential to matter, so that one body may act on another body at a distance through a vacuum, without the mediation of any thing else by and through which their action and force may be conveyed from one to the other, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting constantly acc
Vacuum energy is an underlying background energy that exists in space throughout the entire universe. The vacuum energy is a special case of zero-point
Vacuum energy is an underlying background energy that exists in space throughout the entire universe. The vacuum energy is a special case of zero-point energy that relates to the quantum vacuum.
The effects of vacuum energy can be experimentally observed in various phenomena such as spontaneous emission, the Casimir effect, and the Lamb shift, and are thought to influence the behavior of the Univ
Vacuum energy is an underlying background energy that exists in space throughout the entire universe. The vacuum energy is a special case of zero-point energy that relates to the quantum vacuum.
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