scholarly journals Energy, momentum, mass, and velocity of a moving body in the light of gravitomagnetic theory

2014 ◽  
Vol 92 (10) ◽  
pp. 1074-1081
Author(s):  
Sergey G. Fedosin
Keyword(s):  
Electromagnetic Fields ◽  
Characteristic Size ◽  
Field Approximation ◽  
Weak Field ◽  
The Body ◽  
Covariant Theory ◽  
Gravitational Fields ◽  
Moving Body ◽  
Strong Gravitation ◽  
Energy And Momentum

In the weak-field approximation of the covariant theory of gravitation the 4/3 problem is formulated for internal and external gravitational fields of a body in the form of a uniform ball. The dependence of the energy and the mass of the moving body on the energy of the field accompanying the body, as well as the dependence on the characteristic size of the body are described. Additions in the energy and the momentum of the system, defined by the energy and momentum of the gravitational and electromagnetic fields, associated with the body, are explicitly calculated. The conclusion is made that the energy and the mass of the system can be described through the energy of ordinary and strong gravitation and through the energies of electromagnetic fields of particles that compose the body.

scholarly journals Energy, Momentum, Mass and Velocity of a Moving Body

2017 ◽  
Author(s):  
Sergey G. Fedosin
Keyword(s):  
Electromagnetic Fields ◽  
Characteristic Size ◽  
Field Approximation ◽  
Weak Field ◽  
The Body ◽  
Covariant Theory ◽  
Gravitational Fields ◽  
Strong Gravitation ◽  
Theory Of Gravitation ◽  
Energy And Momentum

In the weak-field approximation of covariant theory of gravitation the problem of 4/3 is formulated for internal and external gravitational fields of a body in the form of a ball. The dependence of the energy and the mass of the moving substance on the energy of field accompanying the substance, as well as the dependence on the characteristic size of the volume occupied by the substance are described. Additives in the energy and the momentum of the body, defined by energy and momentum of the gravitational and electromagnetic fields associated with the body are explicitly calculated. The conclusion is made that the energy and the mass of the body can be described by the energy of ordinary and strong gravitation, and through the energies of electromagnetic fields of particles that compose the body.

The Einstein–Maxwell-particle system in the York canonical basis of ADM tetrad gravity. Part 2. The weak field approximation in the 3-orthogonal gauges and Hamiltonian post-minkowskian gravity: the N-body problem and gravitational waves with asymptotic background 1This paper is one of three companion papers published in the same issue of Can. J. Phys.

2012 ◽  
Vol 90 (11) ◽  
pp. 1077-1130 ◽  
Author(s):  
David Alba ◽  
Luca Lusanna
Keyword(s):  
Electromagnetic Field ◽  
Gravitational Waves ◽  
Particle System ◽  
Canonical Basis ◽  
Field Approximation ◽  
Weak Field ◽  
N Body Problem ◽  
Hamilton Equations ◽  
Weak Field Approximation ◽  
Tetrad Gravity

In this second paper we define a post-minkowskian (PM) weak field approximation leading to a linearization of the Hamilton equations of Arnowitt–Deser–Misner (ADM) tetrad gravity in the York canonical basis in a family of nonharmonic 3-orthogonal Schwinger time gauges. The York time 3K (the relativistic inertial gauge variable, not existing in newtonian gravity, parametrizing the family, and connected to the freedom in clock synchronization, i.e., to the definition of the the shape of the instantaneous 3-spaces) is set equal to an arbitrary numerical function. The matter are considered point particles, with a Grassmann regularization of self-energies, and the electromagnetic field in the radiation gauge: an ultraviolet cutoff allows a consistent linearization, which is shown to be the lowest order of a hamiltonian PM expansion. We solve the constraints and the Hamilton equations for the tidal variables and we find PM gravitational waves with asymptotic background (and the correct quadrupole emission formula) propagating on dynamically determined non-euclidean 3-spaces. The conserved ADM energy and the Grassmann regularization of self-energies imply the correct energy balance. A generalized transverse–traceless gauge can be identified and the main tools for the detection of gravitational waves are reproduced in these nonharmonic gauges. In conclusion, we get a PM solution for the gravitational field and we identify a class of PM Einstein space–times, which will be studied in more detail in a third paper together with the PM equations of motion for the particles and their post-newtonian expansion (but in the absence of the electromagnetic field). Finally we make a discussion on the gauge problem in general relativity to understand which type of experimental observations may lead to a preferred choice for the inertial gauge variable 3K in PM space–times. In the third paper we will show that this choice is connected with the problem of dark matter.

scholarly journals Discovering the forbidden Raman modes at the edges of layered materials

2018 ◽  
Vol 4 (12) ◽  
pp. eaau6252 ◽  
Author(s):  
Yao Guo ◽  
Weixuan Zhang ◽  
Hanchun Wu ◽  
Junfeng Han ◽  
Yongliang Zhang ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Electromagnetic Fields ◽  
Scattered Light ◽  
Layered Materials ◽  
The Body ◽  
Body Region ◽  
Edge Type ◽  
Body Regions ◽  
Raman Modes ◽  
Raman Study

The edges of layered materials have unique properties that substantially differ from the body regions. In this work, we perform a systematic Raman study of the edges of various layered materials (MoS2, WS2, WSe2, PtS2, and black phosphorus). The Raman spectra of the edges feature newly observed forbidden Raman modes, which are originally undetectable from the body region. By selecting the edge type and the polarization directions of the incident and scattered light, all forbidden Raman modes are distinctly detected. Optical simulations show that the edges of layered materials drastically distort the electromagnetic fields of both the incident and scattered light, so that the light interacts with the edges in a distinct way, which differs from its interactions with the body regions.

scholarly journals Computation of electrostatic fields in anisotropic human tissues using the Finite Integration Technique (FIT)

2005 ◽  
Vol 2 ◽  
pp. 309-313 ◽  
Author(s):  
V. C. Motresc ◽  
U. van Rienen
Keyword(s):  
Coordinate System ◽  
Electromagnetic Fields ◽  
Human Body ◽  
Local Coordinate System ◽  
Anisotropic Materials ◽  
The Body ◽  
Integration Technique ◽  
Data Set ◽  
Computer Data ◽  
Finite Integration Technique

Abstract. The exposure of human body to electromagnetic fields has in the recent years become a matter of great interest for scientists working in the area of biology and biomedicine. Due to the difficulty of performing measurements, accurate models of the human body, in the form of a computer data set, are used for computations of the fields inside the body by employing numerical methods such as the method used for our calculations, namely the Finite Integration Technique (FIT). A fact that has to be taken into account when computing electromagnetic fields in the human body is that some tissue classes, i.e. cardiac and skeletal muscles, have higher electrical conductivity and permittivity along fibers rather than across them. This property leads to diagonal conductivity and permittivity tensors only when expressing them in a local coordinate system while in a global coordinate system they become full tensors. The Finite Integration Technique (FIT) in its classical form can handle diagonally anisotropic materials quite effectively but it needed an extension for handling fully anisotropic materials. New electric voltages were placed on the grid and a new averaging method of conductivity and permittivity on the grid was found. In this paper, we present results from electrostatic computations performed with the extended version of FIT for fully anisotropic materials.

QUANTUM FIELDS WITH MODIFIED DISPERSION RELATIONS IN CURVED SPACES

2011 ◽  
Vol 20 (05) ◽  
pp. 745-756 ◽  
Author(s):  
FRANCISCO DIEGO MAZZITELLI
Keyword(s):  
Vector Field ◽  
General Structure ◽  
Scalar Fields ◽  
Field Approximation ◽  
Weak Field ◽  
Dispersion Relations ◽  
Quantum Fields ◽  
Renormalization Procedure ◽  
Modified Dispersion Relations ◽  
Weak Field Approximation

We discuss the renormalization procedure for quantum scalar fields with modified dispersion relations in curved spacetimes. We consider two different ways of introducing modified dispersion relations: through the interaction with a dynamical temporal vector field, as in the context of the Einstein–Aether theory, and breaking explicitly the covariance of the theory, as in Hǒrava–Lifshitz gravity. Working in the weak field approximation, we show that the general structure of the counterterms depends on the UV behavior of the dispersion relations and on the mechanism chosen to introduce them.

Impact of non-thermal electrons on spatial damping: a kinetic model for the parallel propagating modes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Sarfraz ◽  
Gohar Abbas ◽  
Hashim Farooq ◽  
I. Zeba
Keyword(s):  
Kinetic Model ◽  
Wave Spectrum ◽  
Field Approximation ◽  
Weak Field ◽  
Distribution Functions ◽  
Global Perspective ◽  
Energetic Electrons ◽  
Thermal Anisotropy ◽  
Spatial Damping

Abstract A sequence of in situ measurements points the presence of non-thermal species in the profile of particle distributions. This study highlights the role of such energetic electrons on the wave-spectrum. Using Vlasov–Maxwell’s model, the dispersion relations of the parallel propagating modes along with the space scale of damping are discussed using non-relativistic bi-Maxwellian and bi-Kappa distribution functions under the weak field approximation, i.e., ω − k . v > Ω 0 $\left\vert \omega -\mathbf{k}.\mathbf{v}\right\vert { >}{{\Omega}}_{0}$ . Power series and asymptotic expansions of plasma dispersion functions are performed to derive the modes and spatial damping of waves, respectively. The role of these highly energetic electrons is illustrated on real frequency and anomalous damping of R and L-modes which is in fact controlled by the parameter κ in the dispersion. Further, we uncovered the effect of external magnetic field and thermal anisotropy on such spatial attenuation. In global perspective of the kinetic model, it may be another step.

scholarly journals Lorentz Symmetry Group, Retardation, Intergalactic Mass Depletion and Mechanisms Leading to Galactic Rotation Curves

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1693
Author(s):  
Asher Yahalom
Keyword(s):  
Dark Matter ◽  
Galactic Center ◽  
Field Approximation ◽  
Weak Field ◽  
Current Approach ◽  
Galactic Rotation ◽  
Theory Of Relativity ◽  
Detailed Model ◽  
The Galaxy ◽  
Retardation Effects

The general theory of relativity (GR) is symmetric under smooth coordinate transformations, also known as diffeomorphisms. The general coordinate transformation group has a linear subgroup denoted as the Lorentz group of symmetry, which is also maintained in the weak field approximation to GR. The dominant operator in the weak field equation of GR is thus the d’Alembert (wave) operator, which has a retarded potential solution. Galaxies are huge physical systems with dimensions of many tens of thousands of light years. Thus, any change at the galactic center will be noticed at the rim only tens of thousands of years later. Those retardation effects are neglected in the present day galactic modelling used to calculate rotational velocities of matter in the rims of the galaxy and surrounding gas. The significant differences between the predictions of Newtonian instantaneous action at a distance and observed velocities are usually explained by either assuming dark matter or by modifying the laws of gravity (MOND). In this paper, we will show that, by taking general relativity seriously without neglecting retardation effects, one can explain the radial velocities of galactic matter in the M33 galaxy without postulating dark matter. It should be stressed that the current approach does not require that velocities v are high; in fact, the vast majority of galactic bodies (stars, gas) are substantially subluminal—in other words, the ratio of vc≪1. Typical velocities in galaxies are 100 km/s, which makes this ratio 0.001 or smaller. However, one should consider the fact that every gravitational system, even if it is made of subluminal bodies, has a retardation distance, beyond which the retardation effect cannot be neglected. Every natural system, such as stars and galaxies and even galactic clusters, exchanges mass with its environment, for example, the sun loses mass through solar wind and galaxies accrete gas from the intergalactic medium. This means that all natural gravitational systems have a finite retardation distance. The question is thus quantitative: how large is the retardation distance? For the M33 galaxy, the velocity curve indicates that the retardation effects cannot be neglected beyond a certain distance, which was calculated to be roughly 14,000 light years; similar analysis for other galaxies of different types has shown similar results. We demonstrate, using a detailed model, that this does not require a high velocity of gas or stars in or out of the galaxy and is perfectly consistent with the current observational knowledge of galactic and extra galactic material content and dynamics.

scholarly journals Methods that Move: A Physical Performative Pedagogy of Subjectivity

2013 ◽  
Vol 30 (3) ◽  
pp. 256-273 ◽  
Author(s):  
Jessica Francombe
Keyword(s):  
Body Politic ◽  
The Body ◽  
Research Projects ◽  
Body Work ◽  
Moving Body ◽  
Performative Pedagogy ◽  
A Site

Driven by a desire to interrogate and articulate the role and place of the body in the study of sport, this paper encourages those who are incited by a richer understanding of the physical to expand and elaborate upon the fleshy figuration that guides the research projects and practices/strategies of the present. This call for papers is an opportunity to unpack the methodological impetus of “body work” (Giardina & Newman, 2011a) and to locate it within the nexus of dialogues that expressly seek to reengage an eclectic body politic at precisely the time when the body is a site of continuous scrutinizing and scientific confession. As researchers we grapple with and problematize method(ologies) in light of the conjunctural demands placed upon our scholarship and so I reflect on a recently conducted project and the methodological moments that it brought to light. Conceptualized in terms of a physical performative pedagogy of subjectivity, I tentatively forward a discussion of what moving methods might look and feel like and thus I question why, when we research into physical, sporting, (in)active experiences, do we refrain from putting the body to work? Why do we not theorize the body through the moving body?

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