arXiv subjects

Y. Friedman

Publications and source records attributed to Y. Friedman.

11 recordsLinked to original sources

arXiv2026

The Relativistic Gravitational Field of a Spherically Symmetric Extended Body

We investigate the gravitational field of an extended spherically symmetric body within the framework of Extended Relativity (ER), a Lorentz-covariant formulation of relativistic gravity on a Minkowski background. Using a relativistic superposition principle for retarded gravitational fields, we derive an explicit metric for an extended body by integrating the contributions of its mass elements. The resulting metric reproduces the standard gravitational time dilation of a point source and agrees with the classical tests of General Relativity in the appropriate limits. However, unlike the exact Newtonian shell theorem and the Schwarzschild exterior solution, the external field depends weakly on the internal mass distribution through higher-order corrections. These corrections decay rapidly with distance but become significant near compact objects. We analyze the corresponding admissible-velocity geometry, derive the motion equations for test particles, and compare the predictions of extended-body and point-source models. For neutron stars, the corrections noticeably modify the local light-velocity structure near the surface. For the Earth, the corrections are small but produce measurable differences in round-trip light travel times to the International Space Station. The formalism provides a transparent relativistic description of extended gravitational sources and offers a framework for studying relativistic corrections due to internal structure in strong-field and precision-measurement regimes.

gr-qc↗

arXiv2026

A unifying physically meaningful relativistic action

We introduce a relativistic action that provides a unified and physically meaningful description of particle dynamics in external fields. The proposed action is constructed to be Lorentz covariant and reduces to the standard classical action in the appropriate limit. It incorporates gravitational and electromagnetic interactions within a single framework and leads to equations of motion consistent with known physical laws. The formulation offers a new perspective on relativistic dynamics and suggests a pathway toward unification of fundamental interactions.

physics.gen-ph↗

arXiv2026

Superposition Principle in Relativistic Gravity

We develop a framework for superposition in relativistic gravity within Extended Relativity (ER), a Lorentz-covariant theory formulated in flat spacetime. In this approach, gravitational fields are described by deviations from the Minkowski metric associated with individual sources, and multi-source configurations are constructed through a superposition principle linear in the source parameters. The resulting metric preserves Lorentz covariance and reproduces the standard classical tests of General Relativity in the appropriate limits. We derive the explicit form of the superposed field for multiple moving sources and analyze its properties in both near and far zones. The formalism provides a consistent and physically transparent description of interacting gravitational sources and forms the basis for applications to relativistic dynamics and gravitational radiation.

physics.gen-ph↗

arXiv2019

A geometric relativistic dynamics under any conservative force

Riemann's principle "force equals geometry" provided the basis for Einstein's General Relativity - the geometric theory of gravitation. In this paper, we follow this principle to derive the dynamics for any static, conservative force. The geometry of spacetime of a moving object is described by a metric obtained from the potential of the force field acting on it. We introduce a generalization of Newton's First Law - the \emph{Generalized Principle of Inertia} stating that: \emph{An inanimate object moves inertially, that is, with constant velocity, in \emph{its own} spacetime whose geometry is determined by the forces affecting it}. Classical Newtonian dynamics is treated within this framework, using a properly defined \emph{Newtonian metric} with respect to an inertial lab frame. We reveal a physical deficiency of this metric (responsible for the inability of Newtonian dynamics to account for relativistic behavior), and remove it. The dynamics defined by the corrected Newtonian metric leads to a new \emph{Relativistic Newtonian Dynamics} for both massive objects and massless particles moving in any static, conservative force field, not necessarily gravitational. This dynamics reduces in the weak field, low velocity limit to classical Newtonian dynamics and also exactly reproduces the classical tests of General Relativity, as well as the post-Keplerian precession of binaries.

physics.gen-ph↗

arXiv2018

Testing the influence of acceleration on time dilation using a rotating MÖssbauer absorber

The aim of the experiment series was to test the influence of acceleration on time dilation by measuring the relative spectral shift between the resonance spectra of a rotating Mossbauer absorber with acceleration anti-parallel and parallel to the direction of the incident beam. Based on the experiences and know-how acquired in our previous experiments, We collected data for rotation frequencies up to 510Hz in both directions of rotation and also used different slits. For each run with high rotation, we observed a stable statistically significant relative shift between the spectra of the two states with opposite acceleration. This indicates the influence of acceleration on time dilation. However, we found that this shift also depends on the choice of the slit, and on the direction of rotation. These new unexpected findings, resulting from the loss of symmetry in obtaining the resonant lines in the two states, could overshadow the relative shift due to acceleration. This loss of the symmetry is caused by the deflection of the radiative decay due to the Nuclear Lighthouse effect from the rotating Mossbauer absorber. We also found that it is impossible to keep the alignment (between the optical and the dynamical rotor systems) with accuracy needed for such experiment, for long runs, which resulted in the reduction of the accuracy of the observed relative shift. These prevent us to claim with certainty the influence of acceleration on time dilation using the currently available technology. An improved KB optics with focal spot of less than 1 micron to avoid the use of a slit and a more rigid mounting of the rotor system, are necessary for the success of such experiment. Hopefully, these findings together with the indispensable plan for a conclusive experiment presented in the paper, will prove useful to future experimentalists wishing to pursue such an experiment.

physics.acc-ph↗

arXiv2017

Predicting the relativistic periastron advance of a binary without curving spacetime

Relativistic Newtonian Dynamics, the simple model used previously for predicting accurately the anomalous precession of Mercury, is now applied to predict the periastron advance of a binary. The classical treatment of a binary as a two-body problem is modified to account for the influence of the gravitational potential on spacetime. Without curving spacetime, the model predicts the identical equation for the relativistic periastron advance as the post-Newtonian approximation of general relativity formalism thereby providing further substantiation of this model.

physics.gen-ph↗

arXiv2017

Gravitational Deflection in Relativistic Newtonian Dynamics

In a recent series of papers, the authors introduced a new Relativistic Newtonian Dynamics (RND) and tested its validity by the accurate prediction of the gravitational time dilation, the anomalous precession of Mercury, the periastron advance of any binary and the Shapiro time delay. This dynamics incorporates the influence of potential energy on spacetime in Newtonian dynamics and, unlike Einstein's General Relativity, treats gravity as a force without the need to curve spacetime. In this paper, this dynamics is applied to derive the gravitational deflection of both objects with non-zero mass and of massless particles passing the strong gravitating field of a massive body. Equations for the trajectory and the resulting analytical expressions for the deflection angle, in terms of the distance and velocity at the point of closest approach to the massive object, were derived in both cases. It is shown that with a carefully defined limit, the trajectory of a massless particle is the limiting case of that of an object with non-zero mass. In the "weak" deflection limit, the derived expression for the deflection angle of a massless particle (photon) reproduces the experimentally tested Einstein's formula for weak gravitational lensing of a light ray, thereby providing another test for the validity of the RND.

physics.gen-ph↗

arXiv2016

Predicting Mercury's Precession using Simple Relativistic Newtonian Dynamics

We present a new simple relativistic model for planetary motion describing accurately the anomalous precession of the perihelion of Mercury and its origin. The model is based on transforming Newton's classical equation for planetary motion from absolute to real spacetime influenced by the gravitational potential and introducing the concept of influenced direction.

physics.gen-ph↗

arXiv2010

The scalar complex potential and the Aharonov-Bohm effect

The Aharonov-Bohm effect is traditionally attributed to the effect of the electromagnetic 4-potential $A$, even in regions where both the electric field $\mathbf{E}$ and the magnetic field $\mathbf{B}$ are zero. The AB effect reveals that multiple-valued functions play a crucial role in the description of an electromagnetic field. We argue that the quantity measured by AB experiments is a difference in values of a multiple-valued complex function, which we call a complex potential or {pre-potential. We show that any electromagnetic field can be described by this pre-potential, and give an explicit expression for the electromagnetic field tensor through this potential. The pre-potential is a modification of the two scalar potential functions.

math-ph↗

arXiv2009

The scalar complex potential of the electromagnetic field

In this paper, we define a scalar complex potential $\mathcal{S}$ for an arbitrary electromagnetic field. This potential is a modification of the two scalar potential functions introduced by E. T. Whittaker. By use of a complexified Minkowski space $M$, we decompose the usual Lorentz group representation on $M$ into a product of two commuting new representations. These representations are based on the complex Faraday tensor. For a moving charge and for any observer, we obtain a complex dimensionless scalar which is invariant under one of our new representations. The scalar complex potential is the logarithm of this dimensionless scalar times the charge value. We define a conjugation on $M$ which is invariant under our representation. We show that the Faraday tensor is the derivative of the conjugate of the gradient of the complex potential. The real part of the Faraday tensor coincides with the usual electromagnetic tensor of the field. The potential $\mathcal{S}$, as a complex-valued function on space-time, is described as an integral over the distribution of the charges generating the electromagnetic field. This potential is like a wave function description of the field. If we chose the Bondi tetrad (called also Newman-Penrose basis) as a basis on $M$, the components of the Faraday vector at each point may be derived from $\mathcal{S}$ by $ F_j=E_j+iB_j={\partial}^ν(α_j)_ν^λ{\partial}_λ\mathcal{S}$, where $(α_j)$ are the known $α$-matrices of Dirac. This fact indicates that our potential may build a "bridge" between classical and quantum physics.

physics.gen-ph↗

arXiv2008

Backwards on Minkowski's road. From 4D to 3D Maxwellian electromagnetism

Minkowski's concept of a four-dimensional physical space is a central paradigm of modern physics. The three-dimensional Maxwellian electrodynamics is uniquely generalized to the covariant four-dimensional form. Is the (1+3) decomposition of the covariant four-dimensional form unique? How do the different sign assumptions of electrodynamics emerge from this decomposition? Which of these assumptions are fundamental and which of them may be modified? How does the Minkowski space-time metric emerge from this preliminary metric-free construction? In this paper we are looking for answers to the problems mentioned. Our main result is the derivation of four different possible sets of electrodynamic equations which may occur in different types of isotropic electromagnetic media. The wave propagation in each of these media is described by the Minkowskian optical metrics. Moreover, the electric and magnetic energies are nonnegative in all cases. We also show that the correct directions of the Lorentz force (as a consequence of the Dufay and the Lenz rules) hold true for all these cases. However, the differences between these four types of media must have a physical meaning. In particular, the signs of the three electromagnetic invariants are different.

gr-qc↗