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Einstein's special and general relativity are relics from before quantum physics. If forces are transmitted by quanta, this must also apply to gravity. As light consist of quanta, it is only logical that gravitational quanta interact with light. In my article "Cognitive bias in physics with respect to Einstein's relativity, demonstrated by the famous experiment of Pound and Rebka (1960), which in reality refutes Einstein's general relativity" [R. G. Ziefle, Phys. Essays 35, 91 (2022)], I could demonstrate that Einstein's "proper time" t0 does not refer to reference frames but to gravitational potentials. That is why "Newtonian quantum gravity" [R. G. Ziefle, Phys. Essays 33, 99 (2020)] can predict the correct curvature of a light beam at the surface of the Sun. Also, the phenomena observed at the binary pulsar PSR B1913þ16 can precisely be predicted by merely applying Kepler's second law. If gravitational quanta move away from masses with the constant speed c of light, this coincides with Einstein's postulate of a constant speed c of light with respect to reference frames, as a mass, such as a star or a planet, can also be defined as a reference frame. Therefore, Einstein's found by chance an artificial and complicated method to calculate changes in space-time caused by motion, which are in reality additional gravitational effects caused by the relative velocity between gravitational quanta emitted by masses and other masses or photons. [ABSTRACT FROM AUTHOR]

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The well-known experiments performed by Pound and Rebka already in the 1960s confirmed the effect of gravitational time dilation, which had been predicted earlier within the framework of the general relativity theory. However, since photon exchange occurred in the course of these experiments on comparing the frequencies of nuclear resonance fluorescence at various altitudes, the reasons underlying the origin of this effect are explained in the literature by two different and, in fact, alternative presumed physical phenomena. According to the first explanation, clocks locate higher run faster, which is due to an increase in the gravitational potential with increasing distance from the Earth, whereas ascending and descending photons do not change their frequency (by the same clock, e.g., that of the so-called outside observer). According to the second explanation, the clock rate is the same at different altitudes, but the ascending photons undergo a redshift since they lose their energy, while the descending photons undergo a blueshift since they acquire energy. Other combined interpretations of the gravitational time dilation, which presume that the both phenomena exist simultaneously, are proposed in the literature. We propose an experiment with two clocks being active hydrogen masers, one of which is located at the bottom of a high-rise building, and the other, on the top of the building. In this case, time is measured by the first and second clocks during a sufficiently long time interval. After that, the masers are placed at one point, and their indications are compared. In this case, the photon exchange is not required for comparison of the clock readings, and, therefore, the method proposed allows one to reveal the actual reason of the effect under consideration. Numerical estimations are made, which allow for the accompanying effects influencing the measurement accuracy. Critical analysis of the earlier experiments shows that they are either equivocal, or are not absolutely impeccable from the methodology viewpoint. [ABSTRACT FROM AUTHOR]

The physics of low-energy quantum systems is usually studied without explicit consideration of the background spacetime. Phenomena inherent to quantum theory in curved spacetime, such as Hawking radiation, are typically assumed to be relevant only for extreme physical conditions: at high energies and in strong gravitational fields. Here we consider low-energy quantum mechanics in the presence of gravitational time dilation and show that the latter leads to the decoherence of quantum superpositions. Time dilation induces a universal coupling between the internal degrees of freedom and the centre of mass of a composite particle. The resulting correlations lead to decoherence in the particle position, even without any external environment. We also show that the weak time dilation on Earth is already sufficient to affect micrometre-scale objects. Gravity can therefore account for the emergence of classicality and this effect could in principle be tested in future matter-wave experiments. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Physics is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It has long been suspected by general relativists that physicists who do not specialize in general relativity (GR) believe that special relativity (SR) is incapable of modeling dynamics within accelerated reference frames. Consequently, many physicists may conclude that certain phenomena, such as time dilation due to acceleration, can only be described with GR. The fact of the matter is, as long as spacetime is flat, SR is fully capable of describing the dynamics of accelerated reference frames. In the classic textbook Gravitation, the authors state that "special relativity was developed precisely to predict the physics of accelerated objects." To quote Sean Carroll in his textbook Spacetime and Geometry, "The notion of acceleration in special relativity has a bad reputation, for no good reason." Finally, in a quote that drives the main point of this article home, the late general relativist Alfred Schild once said, "A good many believe that [the twin] paradox can only be resolved by the general theory of relativity. They find great comfort in this because they don't know any general relativity." [ABSTRACT FROM AUTHOR]

The general theory of relativity (GTR) has proved to accurately describe all gravitational aspects of our universe. This theory was developed by Einstein under the premises of the principle of equivalence to describe the behavior of inertial systems in accelerated reference frames, but the physical basis for the principle of equivalence and for the existence of accelerated reference frames remains to be understood. Here, we postulate that the principle of equivalence could be explained in terms of an accelerated flow of space toward the origin of the gravitational field, which would explain the accelerated reference frames. We provide evidence that the gravitational constant predicts the observed increase in the Hubble constant from early to late universe. This suggests that gravity and accelerated expansion of the universe could derive from the same physical principle depending on the mass density operating in each process. Massinduced accelerated space expansion through a hypothetical fourth spatial dimension could explain the curvature of spacetime. It would be the projection of the expanded space to our threedimensional universe what would lead to relativistic gravitational effects such as time dilation, redshift, and black hole formation. Therefore, a gravitational theory can be envisioned, halfway between classical mechanics and GTR. [ABSTRACT FROM AUTHOR]

The general theory of relativity extends the special theory of relativity to account for gravity (acceleration) and results in the postulation that matter curves spacetime, where gravitation is the embodiment of the spacetime curvature. The curvature of spacetime is modeled using Riemannian geometry. In this paper, it is proposed that matter rotates spacetime hyperbolically, rather than curves spacetime. As a result, gravitation is the embodiment of the hyperbolic rotation of spacetime. Regions in spacetime that have a larger magnitude of rotation relative to other regions of spacetime, ceteris paribus, experience stronger gravity, gravitational time dilation, gravitational length contraction, and gravitational frequency shift toward the red (blue) in the electromagnetic waves moving away (toward). [ABSTRACT FROM AUTHOR]

The Theory of Relativity, in both the Special and General cases, possesses profound inferences concerning the nature of time as a physical component of universal structure, and not as either an abstract concept or a universal entropic progression as is commonly perceived. While the time-slowing observations of what is known as Relativistic "time dilation" are well documented, the temporal interpretations of such dilation effects were critically affected by a Newtonian view of universally invariant time. Consequently, the most sophisticated interpretations of time dilation were parasitically molded by archaic views of physical time and have remained essentially unchallenged for a century, inhibiting any attempts to functionally integrate the observations of Relativity with Newtonian Mechanics. By freeing relativistic observations from the limited paradigm of Newtonian temporal concepts, an alternative, robust interpretation of Special Relativity, one acting in concert with the actions of bodies as described by Newtonian Mechanics, is produced and discussed. [ABSTRACT FROM AUTHOR]

According to Einstein's general theory of relativity, a clock runs more slowly if it is close to a large gravitating object. This principle was highlighted in the movie "Interstellar," in which the main character spends several hours on a planet orbiting a massive black hole, and returns to find that his young daughter has become an elderly woman. In the movie, one hour on the planet equates to seven years on Earth. The same effect can be measured on a much smaller scale by changing locations within Earth's gravitational field. Using atomic clocks, we have compared the ticking of time at Colorado College (elevation 1845 m above sea level), at the United States Air Force Academy (elevation 2165 m), and near the summit of Pikes Peak (elevation 4288 m). Our results confirm that clocks do indeed tick more quickly at higher altitudes, in accordance with Einstein's theory. This work was carried out as a collaboration of physics majors and faculty at Colorado College (CC) and the United States Air Force Academy (USAFA). The experimental technique is straightforward and our results can be reproduced by other students and teachers, given access to an atomic clock and reasonably large changes in elevation. Indeed, a similar endeavor has been reported by amateur clock enthusiasts. [ABSTRACT FROM AUTHOR]

We present a general relativistic model of a spherical shell of matter with a perfect fluid on its surface coupled to an internal oscillator, which generalizes a model recently introduced by the authors to construct a self-gravitating interferometer (Gooding and Unruh in Phys Rev D 90:044071, ). The internal oscillator evolution is defined with respect to the local proper time of the shell, allowing the oscillator to serve as a local clock that ticks differently depending on the shell's position and momentum. A Hamiltonian reduction is performed on the system, and an approximate quantum description is given to the reduced phase space. If we focus only on the external dynamics, we must trace out the clock degree of freedom, and this results in a form of intrinsic decoherence that shares some features with a proposed 'universal' decoherence mechanism attributed to gravitational time dilation (Pikovski et al in Nat Phys, ). We note that the proposed decoherence remains present in the (gravity-free) limit of flat spacetime, emphasizing that the effect can be attributed entirely to proper time differences, and thus is not necessarily related to gravity. Whereas the effect described in (Pikovski et al in Nat Phys, ) vanishes in the absence of an external gravitational field, our approach bootstraps the gravitational contribution to the time dilation decoherence by including self-interaction, yielding a fundamentally gravitational intrinsic decoherence effect. [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Considers time dilation as a cause of elasticity of the effective Riemannian space. Relation of the cause of space elasticity to an effect of the space curvature on the quantum fluctuations of physical fields; Use of Riemannian space within the framework of general relativity theory as a basis space; Determination of metric tensor.

The role of preferred frames for light propagation and time dilation in the region of a massive, spherical, gravitating bodies, where according to general relativity, space–time curvature is described by the Schwarzschild metric equation, is discussed in the context of the Sagnac effect (for light propagation) and the Hafele–Keating experiment (for time dilation). Predictions for both translational and rotational motion relative to the preferred frame are calculated up to order (v / c) 3 . Different published theoretical calculations of the Sagnac effect are critically reviewed. The conflation in the literature of measured time differences in Sagnac experiments (a classical order v / c effect) and time dilation (a relativistic order (v / c) 2 effect) are also discussed. [ABSTRACT FROM AUTHOR]

This article discusses the topic of interstellar travel and its challenges. It highlights the common misconception that distances between celestial objects are much larger than the objects themselves. The article also explores the concept of relativity and its potential implications for space travel. It presents a mathematical equation that can be used to calculate ship time for long journeys, taking into account the effects of acceleration and time dilation. The article concludes by acknowledging the various practical and human factors that would need to be considered for extended space travel. [Extracted from the article]

Statements about relativistic effects are often subtle. In this essay we will demonstrate that the three classical tests of general relativity, namely perihelion precession, deflection of light and gravitational redshift, are passed perfectly by an extension of Newtonian gravity that includes gravitational time dilation effects while retaining a non-relativistic causal structure. This non-relativistic gravity theory arises from a covariant large speed of light expansion of Einstein's theory of gravity that does not assume weak fields and which admits an action principle. [ABSTRACT FROM AUTHOR]

The theory of special and general relativity causes a "schizophrenic" dilemma in physics. It undeniably provides mathematically correct values, but it is undeniably epistemologically wrong in many respects. Including the relativistic explanation of the gravitational "time dilation" and the curvature of light beams at the surfaces of large masses, the author demonstrates the illogical character of relativistic physics. When one thinks the relativistic explanations of gravitational time dilatation and of the curvature of light rays by masses through to the end, they lead to absurd and contradictory logical conclusions. [ABSTRACT FROM AUTHOR]

The twin paradox has played an important role in the history of special relativity (SR). A precise calculation would require the application of the general theory of relativity (GR) but, neglecting the acceleration phases of the traveling twin, even in SR it is possible to find the correct solution without logical contradictions. Nowadays it is well known that the twin thought experiment seems a paradox as a consequence of a naive application of time dilation and the principle of relativity. The twin who goes on space travel is the one who, returning to the twin at rest, finds the aged brother. Continuing in this pedagogical tradition, we want to add a further consideration. In fact, the experiment has always been explained by considering the two twins immersed in Minkowski's spacetime. It could be interesting, from a didactic point of view, to analyze the same thought experiment without neglecting the Earth's gravitational field. Indeed, under certain conditions, it may happen that the traveling brother can grow older than his brother at rest. [ABSTRACT FROM AUTHOR]

We review how the kinematic structures of special relativity and quantum mechanics both stem from the relativity principle, i.e., "no preferred reference frame" (NPRF). Essentially, NPRF applied to the measurement of the speed of light c gives the light postulate and leads to the geometry of Minkowski space, while NPRF applied to the measurement of Planck's constant h gives "average-only" projection and leads to the denumerable-dimensional Hilbert space of quantum mechanics. These kinematic structures contain the counterintuitive aspects ("mysteries") of time dilation, length contraction, and quantum entanglement. In this essay, we extend the application of NPRF to the gravitational constant G and show that it leads to the "mystery" of the contextuality of mass in general relativity. Thus, we see an underlying coherence and integrity in modern physics via its "mysteries" and the fundamental constants c, h, and G. It is well known that Minkowski and Einstein were greatly influenced by David Hilbert in their development of special relativity and general relativity, respectively, but relating those theories to quantum mechanics via its non-Boolean Hilbert space kinematics is perhaps surprising. [ABSTRACT FROM AUTHOR]

What would the universe be like if we would give up the principle of equivalence and as a consequence incorporate gravity on a more traditional interaction basis within the theory of special relativity? The current work proposes such a gravitational model where a new law of gravitation is expressed in a Lorentz invariant form and is simultaneously in great agreement with many observations (including general relativity). We find the following predictions so far to be consistent with observations: (1) precession formulas explaining, for example, the Mercury apsidal precession, (2) gravitational bending of light near the limb of a massive object, (3) gravitational redshift, (4) escape velocity near a black hole, (5) several relativistic orbit details are derived in the strong field regime and found to be consistent with GR and also the observed shadow of the M87 black hole. Curved space effects such as gravitational time dilation or Shapiro delay cannot be explained within the realms of special relativity (Sect. 3.11). [ABSTRACT FROM AUTHOR]

In this paper, we study the phenomenon of quantum interference in the presence of external gravitational fields described by alternative theories of gravity. We analyze both non-relativistic and relativistic effects induced by the underlying curved background on a superposed quantum system. In the non-relativistic regime, it is possible to come across a gravitational counterpart of the Bohm–Aharonov effect, which results in a phase shift proportional to the derivative of the modified Newtonian potential. On the other hand, beyond the Newtonian approximation, the relativistic nature of gravity plays a crucial rôle. Indeed, the existence of a gravitational time dilation between the two arms of the interferometer causes a loss of coherence that is in principle observable in quantum interference patterns. We work in the context of generalized quadratic theories of gravity to compare their physical predictions with the analogous outcomes in general relativity. In so doing, we show that the decoherence rate strongly depends on the gravitational model under investigation, which means that this approach turns out to be a promising test bench to probe and discriminate among all the extensions of Einstein's theory in future experiments. [ABSTRACT FROM AUTHOR]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We shown that the internal Schwarzschild-type solution in the field theory of gravity does not lead to infinite pressure inside the body as is the case in general relativity. This occurs as a result of the graviton rest mass because the time-dilation process terminates. [ABSTRACT FROM AUTHOR]

The article presents a mock transcript that intends to illuminate some of the key issues with theoretical physicist Albert Einstein (1879-1955). Topics mentioned include Einstein's concern about the history of science and how it is perceived by the public, his special relativity paper titled "On the Electrodynamics of Moving Bodies," and the book "A Brief History of Time: From the Big Bang to Black Holes," by theoretical physicist Stephen Hawking.

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Observers in relative motion or at different gravitational potentials measure disparate clock rates. These predictions of relativity have previously been observed with atomic clocks at high velocities and with large changes in elevation. We observed time dilation from relative speeds of less than 10 meters per second by comparing two optical atomic clocks connected by a 75-meter length of optical fiber. We can now also detect time dilation due to a change in height near Earth's surface of less than 1 meter. This technique may be extended to the field of geodesy, with applications in geophysics and hydrology as well as in space-based tests of fundamental physics. [ABSTRACT FROM AUTHOR]

We consider gravitational time dilation between stationary observers and present examples which contradict the statement that ‘time slows down as gravity increases’. We furthermore show that this statement cannot be true in general, if gravity strength is defined in an observer independent manner. We also provide a pedagogical introduction to gravitational time dilation, and discuss aspects of this phenomenon, which are often omitted in textbooks on general relativity. [ABSTRACT FROM AUTHOR]

Shows that the field treatment of gravitational fields allows the discovery of a new fundamental feature of gravitation, namely, the origination of effective repulsive forces caused by the time dilation of physical processes in strong gravitational fields. Absence of such forces in general relativity; Observation that the relativistic theory of gravitation exhibits a peculiar mechanism of gravitational self-regulation.

The phase shift induced by a uniform rotation in a Michelson interferometer is re-derived in the geometrical framework of the coordinate-free formalism of general relativity from the co-rotating point of view. The effect is second order in the ratio of the interferometer's speed to the speed of light and further suppressed by the ratio of the length of the interferometer's arms to the radius of rotation. The relation of the effect to gravitational time dilation is discussed. [ABSTRACT FROM AUTHOR]

Abstract: We show that the phase transition from the decelerating universe to the accelerating universe, which is of relevance to the cosmological coincidence problem, is possible in the semiclassically quantized two-dimensional dilaton gravity by taking into account the noncommutative field variables during the finite time. Initially, the quantum-mechanically induced energy from the noncommutativity among the fields makes the early universe decelerate and subsequently the universe is accelerating because the dilaton driven cosmology becomes dominant later. [Copyright &y& Elsevier]

The canonical twin paradox is explained by making a correct use of the principle of equivalence. The role of the principle of equivalence is to provide a physical agent i.e gravity which can supply the required extra aging to the rocket-bound sibling during its acceleration phase through a gravitational time-offset effect. We follow an approach where a novel variation on the twin paradox is used to connect gravity with the desynchronization in the clocks of two spatially distant, identically accelerated observers. It is shown that this approach removes certain drawbacks of an earlier effort which claims to exploit the equivalence principle in explaining the differential aging in the paradox. [ABSTRACT FROM AUTHOR]

Abstract: We propose a test of the gravitational time dilation in general relativity by long term clock comparison between two stations separated in height. The geopotential difference between the two National time keeping centers in China, Lintong and Beijing is around 4000 geopotential unit, which corresponds to the height difference of 400m. Two clocks and are fixed at stations A and B, respectively, which are synchronized at beginning by a portable clock C in a short time period with go-back synchronization approach. After one month, the clock C is again transported between A and B, comparing the records of the keeping time by clocks and , respectively. Calculations show that, after one month, the difference of the time durations between the clocks and is around 121ns, if general relativity is correct. [Copyright &y& Elsevier]

Copyright of Physics Essays is the property of Physics Essays Publication and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

100 years after the invention of General Relativity (GR) and 110 years after the development of Special Relativity (SR) we have to state that until now no single experiment or observation allows any doubt about the validity of these theories within the accuracy of the available data. Tests of GR can be divided into three categories: (i) test of the foundations of GR, (ii) tests of the consequences of GR, and (iii) test of the interplay between GR and quantum mechanics. In the first category, we have tests of the Einstein Equivalence Principle and the structure of the Newton axioms, in the second category we have effects like the gravitational redshift, light defection, gravitational time delay, the perihelion shift, the gravitomagnetic effects as the Lense-Thirring and Schiff effect, and gravitational waves. Tests of the effects of gravity on quantum systems are a first step towards experiments searching for a quantum gravity theory. In this paper, we also highlight practical applications in positioning, geodesy, and the International Atomic Time. After 100 years, GR can now definitely be regarded also as practical and applied science. [ABSTRACT FROM AUTHOR]

We show how students can be led to an understanding of the connection between special relativity and general relativity by considering the time dilation effect of clocks placed on the surface of the Earth. This paper is written as a Socratic dialog between a lecturer and a student. [ABSTRACT FROM AUTHOR]

This paper has a pedagogical aim. Indeed, by using the relativistic velocity-addition and Einstein's equivalence principle (EEP), we want to analyse in a simple way the physics of time on a rotating non-inertial frame. We use a didactic approach considering four friends. The first is in the laboratory, the second at rest on the disk at radius r, the third and fourth ride a bicycle in opposite directions but with the same speed with respect to the platform. Since, in General Relativity, time can flow differently at every point, the concept of speed is often ambiguous. [ABSTRACT FROM AUTHOR]

The Italian government's Ministry of Public Education, which defines the high school curricula, has introduced almost all the topics of modern physics for students in their last year of high school. The theory of relativity is, perhaps, the argument most developed. The students, doing a web search, read that the speed of light can take different values in General Relativity (GR). We have noticed that this concept creates a lot of confusion and also a misconception in young students. In this paper, we want to describe a lecture given in the classroom about this topic. [ABSTRACT FROM AUTHOR]

The problem of synchronizing the onboard clocks of navigation satellites is examined from a relativistic standpoint using the concept of "coordinate simultaneity." This concept makes it possible to uniquely interpret the results of synchronization in terms of the general theory of relativity. An algorithm for processing intersatellite measurements is formulated in terms of an instrumental realization of the proper time of a spacecraft and the coordinate time of a reference frame. Rules for transformation between the coordinate and proper time frames are given. An analytic expression is obtained for the periodic relativistic correction to the estimated proper value of the relative clock drift, expressed in terms of the time coordinate of an earthbound observer. The value of this correction exceeds the permissible synchronization error and must be taken into account in processing intersatellite measurements. The error in determining the relativistic correction, which provides an upper bound on the period for uploading of ephemeris data on board spacecraft, is calculated [ABSTRACT FROM AUTHOR]