Speed Of Light Research Articles

A Very Fast Reasoning in Favor of the Poincare Group, or of Minkowskian Rather than Euclidean Line Elements

1. We present a very fast derivation of Minkowski’s line element which is the geometric foundation not only of the special Lorentz transformation but of the whole Poincar’e group aka inhomogeneous Lorentz group [1]. The Euclidean line element is excluded using the wave equation and Einstein’s special principle of relativity (Einstein’s first postulate) [2]. For doing so, it is not necessary, 1. to assume the speed of light to be independent of the motion of the observer (Einstein’s second postulate [2], 2. to synchronize watches, 3. to interrelate the coordinate systems of the inertial frames involved; their relative velocity (and hence reciprocity [3]) even plays not any role in the derivation. 4. to make any assumption about the properties of the underlying coordinate transformation such as linearity, uniqueness etc

Stringent Tests of Lorentz Invariance Violation from LHAASO Observations of GRB 221009A.

On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are E_{QG,1}>10 times the Planck energy E_{Pl} for the linear LIV effect, and E_{QG,2}>6×10^{-8}E_{Pl} for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.

Underwater maneuvering target motion analysis using delayed azimuth angles

Accurate position information of an underwater target is the premise of successfully executing underwater missions, and this paper focuses on underwater target motion analysis (TMA) using delayed azimuth angles. Considering that the underwater sound speed (around 1500 m/s) is much smaller than the speed of light (3 × 108 m/s), the underwater TMA needs to adopt the non-stop model considering the effect of the target movement during signal propagation on state estimation, instead of the traditional go-stop model ignoring the target movement during signal propagation. The existing non-stop model is based on a constant-velocity target, and the model mismatch will make the estimated results biased when it is applied to a maneuvering target. In this paper, we focus on the constant-acceleration (CA) target and propose two methods to solve this problem. One is to extend the non-stop model to the case of a constant-acceleration target. We build the corresponding least squares (LS) estimator and derive the expression of the root mean square error (RMSE) of the LS solution. The other is to directly offset the estimation bias of the CA go-stop model and a bias-compensated algorithm is proposed to improve the performance. Simulations prove that the proposed methods can result in a smaller RMSE than the traditional CA go-stop model. Their RMSEs decrease with the number of measurements and observers and increase with random angle errors. When the number of measurements is small, the RMSE of the established CA non-stop model is smaller than that of the bias-compensated algorithm. As the number of measurements increases, their estimation precisions become gradually equal. The running time of the proposed methods increases with the number of measurements and observers. When the number of observers is small, the bias-compensated algorithm has the advantage of needing less running time. In addition, the running time of the bias-compensated algorithm does not approximately change with the random angle errors, while that of the CA non-stop model increases with the random angle errors.

EXPERIMENT TO DETECT THE ABSOLUTE VELOCITY OF EARTH IN THE UNIVERSE

A number of experiments have been carried out to measure the velocity of earth in the space but absolute velocity of earth could not be detected. One of the most famous Michelson and Morley experiment was conducted in the year 1887 to detect the motion of earth with reference to luminiferous aether a supposed medium permeating space that was thought to be the carrier of light waves but unexpected results were obtained. The experiment has given negative results, MMX type experiments have been repeated so many times with steadily increasing sensitivity from 1902 to 1930 and more recently in the year 2009 by optical resonator but all the experiments confirmed the negative results of MMX. Albert Einstein submitted his special theory of relativity in the year 1905 and stated that there is no medium like aether for propagation of light waves and there is no absolute velocity in the universe, all the motions are relative. Relative velocity of earth has been measured by various methods and observations such as stellar parallax, position of stars and planets, satellite laser ranging, GPS and CMB radiation. Second postulate of STR states that velocity of light is constant in all inertial frames of reference, there is no effect of motion of source of light or observer on the speed of light. As the velocity of light is a universal Constant hence any velocity with reference to speed of light will be absolute velocity. On the basis of second postulate of STR absolute velocity of earth in the universe can be determined by experiment based on the laser light beams. A laser beam may be directed on the fixed screen and movement of laser spot due to motion of earth may be observed. The displacement of laser spot with passage of time may be observed to determine the velocity of earth. In the present article it is explained how the velocity of earth may be detected by measuring displacement of laser spot. The displacement of laser spot from its normal position will determine the absolute velocity of earth in the universe.

On the Speed of Light as a Key Element in the Structure of Quantum Mechanics

We follow the assumption that relativistic causality is a key element in the structure of quantum mechanics and integrate the speed of light, c, into quantum mechanics through the postulate that the (reduced) Planck constant is a function of c with a leading order of the form ℏc∼Λ/cp for a constant Λ>0, and p>1. We show how the limit c→∞ implies classicality in quantum mechanics and explain why p has to be larger than 1. As the limit c→∞ breaks down both relativity theory and quantum mechanics, as followed by the proposed model, it can then be understood through similar conceptual physical laws. We further show how the position-dependent speed of light gives rise to an effective curved space in quantum systems and show that a stronger gravitational field implies higher quantum uncertainties, followed by the varied c. We then discuss possible ways to find experimental evidence of the proposed model using set-ups to test the varying speed of light models and examine analogies of the model based on electrons in semiconductor heterostructures.

Error estimates of exponential wave integrators for the Dirac equation in the massless and nonrelativistic regime

AbstractWe present exponential wave integrator Fourier pseudospectral (EWI‐FP) methods and establish their error estimates of the fully discrete schemes for the Dirac equation in the massless and nonrelativistic regime. This regime involves a small dimensionless parameter where , and is inversely proportional to the speed of light. The solution exhibits highly oscillatory behavior in time and rapid wave propagation in space in this regime. Specifically, the time oscillations have a wavelength of , while the spatial oscillations have a wavelength of , with a wave speed of . We employ (symmetric) exponential wave integrators for temporal derivatives and Fourier spectral discretization for spatial derivatives. We rigorously derive the error bounds which explicitly depend on the mesh size , the time step and the small dimensionless parameter . The error estimates for the EWI‐FP methods demonstrate that their meshing strategy requirement (‐scalability) necessitates setting and when . Finally, some numerical examples are provided to validate the error bounds.

Exploring Quantized Massless Photonic Wave-Particle Duality, Inertial Mass Resistance to Motion & the Speed of Light as Representative of a Higher Dimensional Hyperspace Axis of Subspace Field Unification

Exploring Quantized Massless Photonic Wave-Particle Duality, Inertial Mass Resistance to Motion & the Speed of Light as Representative of a Higher Dimensional Hyperspace Axis of Subspace Field Unification

Exploring Quantized Massless Photonic Wave-Particle Duality, Inertial Mass Resistance to Motion, and the Speed of Light as Representations of a Higher Dimensional Hyperspace Axis within Subspace Field Unification

This paper explores the potentially interlinked, multidimensional nature of three fundamental qualities of reality. First, wave-particle duality is examined as an intrinsic extension of the fundamental two-dimensional electromagnetic wavelength, which permeates into a three-dimensional quantum manifestation of photonic particles. Second, the speed of light is considered as a limiting factor imposed by a multidimensional hyperspatial subspace ether grid, where the tensile locality restricts light's travel. Third, the movement of mass-carrying particles through this subspace ether grid is analyzed as being responsible for inertial resistance—specifically, resistance to changes in motion, including acceleration, deceleration, and changes in relative velocity.This paper then postulates that the massless motion of photonic energy packets at the speed of light, and the inertial resistance of mass-carrying hadronic particles to changes in relative motion, are opposite dimensional aspects of a unified subspace field theory. These aspects, though seemingly distinct, are proposed to occupy opposing sides of the same intersecting hyperspatial axis, within a higher-dimensional etheric reality.

A relativistic scalar model for fractional interaction between dark matter and gravity

Abstract In a series of recent papers we put forward a “fractional gravity”
framework striking an intermediate course between a modified gravity theory and an
exotic dark matter (DM) scenario, which envisages the DM component in virialized
halos to feel a non-local interaction mediated by gravity. The remarkable success
of this model in reproducing several aspects of DM phenomenology motivates us to
look for a general relativistic extension. Specifically, we propose a theory, dubbed
Relativistic Scalar Fractional Gravity or RSFG, in which the trace of the DM stressenergy tensor couples to the scalar curvature via a non-local operator constructed with
a fractional power of the d’Alembertian. We derive the field equations starting from
an action principle, and then we investigate their weak field limit, demonstrating that
in the Newtonian approximation the fractional gravity setup of our previous works is
recovered. We compute the first-order post-Newtonian parameter γ and its relation
with weak lensing, showing that although in RSFG the former deviates from its GR
values of unity, the latter is unaffected. We also perform a standard scalar-vectortensor-decomposition of RSFG in the weak field limit, to highlight that gravitational
waves propagate at the speed of light, though also an additional scalar mode becomes
dynamical. Finally, we derive the modified conservation laws of the DM stress energy
tensor in RSFG, showing that a new non-local force emerges, and hence that the DM
fluid deviates from the geodesic solutions of the field equations.

The Caveman from Space Paradox

A caveman; a primitive human from a prehistoric era. 10 thousand to 40 thousand year old man. Einsteins theory of relativity states that nothing with mass can move faster than the speed of light, and that space and time are not independent. So what does this mean for space travel?

Multiwavelength Observations of Sgr A*. II. 2019 July 21 and 26

We report on the final two days of a multiwavelength campaign of Sgr A* observing in the radio, submillimeter, infrared (IR), and X-ray bands in 2019 July. Sgr A* was remarkably active, showing multiple flaring events across the electromagnetic spectrum. We detect a transient ∼35 minute periodicity feature in Spitzer light curves on 2019 July 21. Time-delayed emission was detected in Atacama Large Millimeter/submillimeter Array light curves, suggesting a hotspot within the accretion flow on a stable orbit. On the same night, we observe a decreased flux in the submillimeter light curve following an X-ray flare detected by Chandra, and we model the feature with an adiabatically expanding synchrotron hotspot occulting the accretion flow. The event is produced by a plasma 0.55 R S in radius with an electron spectrum p = 2.84. It is threaded by a ∼130 Gauss magnetic field and expands at 0.6% the speed of light. Finally, we reveal an unambiguous flare in the IR, submillimeter, and radio, demonstrating that the variable emission is intrinsically linked. We jointly fit the radio and submillimeter light curves using an adiabatically expanding synchrotron hotspot and find it is produced by a plasma with an electron spectrum p = 0.59, 187 Gauss magnetic field, and radius 0.47 R S that expands at 0.029c. In both cases, the uncertainty in the appropriate lower and upper electron energy bounds may inflate the derived equipartition field strengths by a factor of 2 or more. Our results confirm that both synchrotron- and adiabatic-cooling processes are involved in the variable emission’s evolution at submillimeter and IR wavelengths.

Emergent particles of de Sitter: thermal interpretation of the stochastic formalism and beyond

A thermal interpretation of the stochastic formalism of a slow-rolling scalar field in de Sitter (dS) is given. We construct a correspondence between Hubble patches of dS and particles living in another space called an abstract space. By assuming a dual description of scalar fields and classical mechanics in the abstract space, we show that the stochastic evolution of the infrared part of the field is equivalent to the Brownian motion in the abstract space filled with a heat bath of massless particles. The 1st slow-roll condition and the Hubble expansion are also reinterpreted in the abstract space as the speed of light and a transfer of conserved energy, respectively. Inspired by this, we sketch quantum emergent particles, which may realize the Hubble expansion by an exponential particle production. This gives another meaning of dS entropy as entropy per Hubble volume.

Validation of optical conductivity and tailing parameter

A quantum model for optical conductivity that treats light as a particle is presented. Based on this assumption, the optical characteristics of the material are calculated and compared to experimental findings. The band gap energy of a material changes with frequency and refractive index. We provided an equation of the line extrapolated in the Tauc plot. The obtained formula for optical conductivity reveals that the band tailing parameter in the Tauc formula is dependent on the speed of light, the Planck constant, and the material's refractive index. The determination of this constant helps establish the value of the band. The values of this constant are found to be consistent with various experimental results. Two electric conductivities distinguishing Abraham and Minkoswi's light momentum relationship inside materials are proposed.

OO Leo: An Active Contact Binary with Possible Solar-like Differential Rotation

With Transiting Exoplanet Survey Satellite (TESS) high-precision photometry and Large Sky Area Multi-object Fiber Spectroscopic Telescope medium-resolution spectra, we present the first light and radial velocity curve analyses for the eclipsing binary OO Leo. The simultaneous solution suggests that OO Leo is a W-subtype contact binary with a relatively low mass ratio (1/q = 0.173) and a moderate degree of contact (f = 28.1%). The asymmetry and continuous changes observed in the TESS light curve were properly modeled by one retrograde cool spot on its secondary surface. A detailed investigation of the Hα line also confirmed that the secondary star had a high level of magnetic activity. The retrograde longitudinal motion of the spot can be explained by a solar-like differential rotation in the secondary component. The orbital period investigation revealed that OO Leo is undergoing a secular decrease and a cyclic variation in its orbital period. The secular decrease may be mainly caused by mass transfer from the more massive secondary star to the less massive primary star. The cyclic period variation can be explained by the light–time effect of an invisible third body or the cyclic magnetic activity of the secondary star. The long-lived spot migration in the longitudinal direction makes OO Leo an excellent target for investigating the differential rotations of contact binaries.

Global Realism with Bipolar Strings: From Bell Test to Real-World Causal-Logical Quantum Gravity and Brain-Universe Similarity for Entangled Machine Thinking and Imagination

Following Einstein’s prediction that “Physics constitutes a logical system of thought” and “Nature is the realization of the simplest conceivable mathematical ideas”, this topical review outlines a formal extension of local realism limited by the speed of light to global realism with bipolar strings (GRBS) that unifies the principle of locality with quantum nonlocality. The related literature is critically reviewed to justify GRBS which is shown as a necessary and inevitable consequence of the Bell test and an equilibrium-based axiomatization of physics and quantum information science for brain–universe similarity and human-level intelligence. With definable causality in regularity and mind–light–matter unity for quantum superposition/entanglement, bipolar universal modus ponens (BUMP) in GRBS makes quantum emergence and submergence of spacetime logically ubiquitous in both the physical and mental worlds—an unexpected but long-sought simplification of quantum gravity with complete background independence. It is shown that GRBS forms a basis for quantum intelligence (QI)—a spacetime transcendent, quantum–digital compatible, analytical quantum computing paradigm where bipolar strings lead to bipolar entropy as a nonlinear bipolar dynamic and set–theoretic unification of order and disorder as well as linearity and nonlinearity for energy/information conservation, regeneration, and degeneration toward quantum cognition and quantum biology (QCQB) as well as information-conservational blackhole keypad compression and big bang data recovery. Subsequently, GRBS is justified as a real-world quantum gravity (RWQG) theory—a bipolar relativistic causal–logical reconceptualization and unification of string theory, loop quantum gravity, and M-theory—the three roads to quantum gravity. Based on GRBS, the following is posited: (1) life is a living bipolar superstring regulated by bipolar entropy; (2) thinking with consciousness and memory growth as a prerequisite for human-level intelligence is fundamentally mind–light–matter unitary QI logically equivalent to quantum emergence (entanglement) and submergence (collapse) of spacetime. These two posits lead to a positive answer to the question “If AI machine cannot think, can QI machine think?”. Causal–logical brain modeling (CLBM) for entangled machine thinking and imagination (EMTI) is proposed and graphically illustrated. The testability and falsifiability of GRBS are discussed.

Phenomenology of Horndeski gravity under positivity bounds

A set of conditions that any effective field theory needs to satisfy in order to allow for the existence of a viable UV completion, has recently gained attention in the cosmological context under the name of positivity bounds. In this paper we revisit the derivation of such bounds for Horndeski gravity, highlighting the limitations that come from applying the traditional methodology to a theory of gravity on a cosmological background. We then translate these bounds into a complete set of viability conditions in the language of effective field theory of dark energy. We implement the latter into EFTCAMB and explore the large scale structure phenomenology of Horndeski gravity under positivity bounds. We build a statistically significant sample of viable Horndeski models, and derive the corresponding predictions for the background evolution, in terms of w DE, and the dynamics of linear perturbations, in terms of the phenomenological functions μ and Σ, associated to clustering and weak lensing, respectively. We find that the addition of positivity bounds to the traditional no-ghost and no-gradient conditions considerably tightens the theoretical constraints on all these functions. The most significant feature is a strengthening of the correlation μ ≃ Σ, and a related tight constraint on the luminal speed of gravitational waves c 2 T ≃ 1. In this work we demonstrate the strong potential of positivity bounds in shaping the viable parameter space of scalar-tensor theories. This is certainly promising, but it also highlights the importance of overcoming all issues that still plague a rigorous formulation of the positivity bounds in the cosmological context.

Ballistic Photons, Justification of their Structure and Movement Patterns

Aim: The work relates to the fundamentals of quantum physics and photonics, in particular to the formation of photons in two states: elementary particles and electromagnetic radiation, and the parameters of their structure and motion processes. The study of these problems is a relevant and important task, has not been fully studied. In general case, a photon is considered an elementary particle and wave, quantum of energy emitted by its electromagnetic field, which does not exist without moving at the speed of light. However, the presence of the material part of a photon is not always manifested, so a photon is considered a wave of electromagnetic radiation and the photon has no internal structure and dimensions, except for its wave parameters. The process of photon movement is also problematic. It is believed that it exists as a particle at the moment of its origin, and then it is only the movement of a wave, which, when meeting a target, again turns into an elementary particle. Moreover, ballistic photons is not, and their flight occurs by absorption and re-emission of waves by the environment. However, all these factors have contradictions, the elimination of which is the main goal of the work performed. Its scientific novelty is a new justification for the presence and parameters of a ballistic photon and the processes of its movement on the basis of reliable laws of physics. Methodology: The research methodology is based on the general principles of scientific knowledge, on the application of the laws of dialectics and reliable laws of physics. The author's method was also used – this access to the initial level of the material world, which is formed by physical fields and particles on the basis of natural physical constants: the speed of light c, Planck's constant h, gravitational constant G. New Results of the Work: The possibility of the existence of ballistic photons in the dual form of substance and electromagnetic waves is shown, within the framework of the general physical principles of the existence of elementary particles and the real principles of their movement in the material world. It was found that the disappearance of ballistic photons in flight after their birth and their appearance when meeting a target can be explained by their quantum structure and the process of their movement by quantum jumps based on the Heseisenberg uncertainty principle. Conclusions: The presence of the proposed quantum structure of the photon and the process of its movement is ensured by the absence of contradictions with the real laws of the material world that have a strict physical basis. For to confirm the reality of the existence of ballistic photons in the form of a real quantum mechanical particle, having the shape of a regular hexagon with a side of 1/ 6 of the wavelength λ of their radiation, as well as their movement in quantum jumps at 1/ 6 of the length of this wave, an experiment has been proposed. All laboratories with metrological equipment are invited to conduct the experiment.

Galaxy dynamics tracing quantum cosmology beyond [formula omitted]CDM below the de Sitter scale of acceleration

It is proposed that the baryonic Tully–Fisher relation (bTFR) and JWST ’Impossible galaxies’ at cosmic dawn are unified in weak gravity by the trace J of the Schouten tensor below the Sitter scale of acceleration adS=cH, where c is the velocity of light and H is the Hubble parameter. Across adS, J parametrizes short-period galaxy rotation curves and fast gravitational collapse beyond the predictions of ΛCDM. The sensitivity of weak gravitation to J=16R, where R is the Ricci scalar tensor, is derived in infrared gravitation from a consistent limit to quantum gravity, reducing to general relativity in the limit of a small Planck constant. For the first time, it identifies the exact relation a0=c2J/2π of the Milgrom parameter across all redshifts, accounting for the bTFR and early galaxy formation accelerated by a factor ∼J1/8. It predicts a0′(0)<0 at the present epoch.

Constraining gravitational wave velocities using gravitational and electromagnetic wave observations of white dwarf binaries

ABSTRACT Although the general theory of relativity (GR) predicts that gravitational waves (GWs) have exactly the same propagation velocity as electromagnetic (EM) waves, many theories of gravity beyond GR expect otherwise. Accurate measurement of the difference in their propagation speed, or a tight constraint on it, could be crucial to validate or put limits on theories beyond GR. The proposed future space-borne GW detectors are poised to detect a substantial number of Galactic white dwarf binaries (GWDBs), which emit the GW as semimonochromatic signals. Concurrently, these GWDBs can also be identified as optical variable sources. Here we proposed that allocating a GWDB’s optical light curve and contemporaneous GW signal can be used to trace the difference between the velocity of GW and EM waves. Simulating GW and EM wave data from 14 verification binaries (VBs), our method constrains propagation-originated phase differences, limiting the discrepancy between the speed of light (c) and GW ($c_{GW}$). Through the utilization of LISA’s design sensitivity and the current precision in optical observation on GWDB, our study reveals that a four-year observation of the 14 recognized VBs results in a joint constraint that confines $\Delta c/c$ ($\Delta c = c_{\mathrm{GW}} - c$) to the range of $-2.1\times 10^{-12}$ and $4.8\times 10^{-12}$. Additionally, by incorporating this constraint on $c_{\mathrm{GW}}$, we are able to establish boundaries for the mass of the graviton, limiting it to $m_{\mathrm{g}}\le 3\times 10^{-23}\, e\mathrm{V}\,c^{-2}$, and for the parameter associated with local Lorentz violation, $\bar{s}_{00}$, constrained within the range of $-3.4\times 10^{-11}\le \bar{s}_{00}\le 1.5\times 10^{-11}$.

Simulation Study on Constraining Gravitational Wave Propagation Speed by Gravitational Wave and Gamma-ray Burst Joint Observation on Binary Neutron Star Mergers

Theories of modified gravity suggest that the propagation speed of gravitational waves (GW) v g may deviate from the speed of light c. A constraint can be placed on the difference between c and v g with a simple method that uses the arrival time delay between GW and electromagnetic wave simultaneously emitted from a burst event. We simulated the joint observation of GW and short gamma-ray burst signals from binary neutron star merger events in different observation campaigns, involving advanced LIGO (aLIGO) in design sensitivity and Einstein Telescope (ET) joint-detected with Fermi/GBM. As a result, the relative precision of constraint on v g can reach ∼10−17 (aLIGO) and ∼10−18 (ET), which are one and two orders of magnitude better than that from GW170817, respectively. We continue to obtain the bound of graviton mass m g ≤ 7.1(3.2) × 10−20 eV with aLIGO (ET). Applying the Standard-Model Extension test framework, the constraint on v g allows us to study the Lorentz violation in the nondispersive, nonbirefringent limit of the gravitational sector. We obtain the constraints of the dimensionless isotropic coefficients s¯00(4) at mass dimension d = 4, which are −1×10−15<s¯00(4)<9×10−17 for aLIGO and −4×10−16<s¯00(4)<8×10−18 for ET.