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According to general relativity, clocks are the basic measuring devices needed to probe spacetime geometry. However, it is generally accepted that the mass of clocks capable of measuring small time intervals must be bounded from below. In…

General Relativity and Quantum Cosmology · Physics 2026-03-02 Bruno Arderucio Costa , Yafet E. Sanchez Sanchez

As a basis for epistemological study of ``time,'' we analyze three suspect phenomena introduced by modern physics: non-locality, asymmetric aging and advanced interaction. It is shown that all three arise in connection with what has to be…

Quantum Physics · Physics 2007-05-23 A. F. Kracklauer

Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-05 Pierre Magain , Clémentine Hauret

A careful look at an allegedly well-known century-old concept reveals interesting aspects in it that have generally avoided recognition in literature. There are four different kinds of physical observables known or proclaimed as…

General Physics · Physics 2021-02-23 Moses Fayngold

Elementary particles, i.e. the basic constituents of nature, are characterized by quantum recurrences in time. The flow of time of every physical system can be therefore decomposed in elementary cycles of time. This allows us to enforce the…

Quantum Physics · Physics 2013-09-09 Donatello Dolce

Attempts to quantize general relativity encounter an odd problem. The Hamiltonian that normally generates time evolution vanishes in the case of general relativity as a result of diffeomorphism invariance. The theory seems to be saying that…

General Relativity and Quantum Cosmology · Physics 2009-04-23 Olaf Dreyer

Rather than an a priori arena in which events take place, space-time is a construction of our mind making possible a particular kind of ordering of events. As quantum entanglement is a property of states independent of classical distances,…

Quantum Physics · Physics 2015-03-26 Karl Svozil

Because of the non-locality of quantum entanglement, realist approaches to completing quantum mechanics have implications for our conception of space. Quantum gravity also is expected to predict phenomena in which the locality of classical…

History and Philosophy of Physics · Physics 2018-06-01 Lee Smolin

Relativistic length contraction is revisited and a simple but new thought experiment is proposed in which an apparent asymmetric situation is developed between two different inertial frames regarding detection of light that comes from a…

Classical Physics · Physics 2021-11-02 Biplab Raychaudhuri , Souvik Ghose , Arunabha Bhadra

The general relativistic gravitomagnetic clock effect involves a coupling between the orbital motion of a test particle and the rotation of the central mass and results in a difference in the proper periods of two counter-revolving…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Herbert I. M. Lichtenegger , Lorenzo Iorio , Bahram Mashhoon

We provide a brief discussion regarding relativistic limits on the discretization and temporal resolution of time values in a quantum clock. Our clock is characterized by a time observable chosen to be the complement of a bounded and…

Quantum Physics · Physics 2025-10-16 Tommaso Favalli

Time is one of the undisputed foundations of our life in the real world. Here it is argued that inside small isolated quantum systems, time does not pass as we are used to, and it is primarily in this sense that quantum objects enjoy only…

General Physics · Physics 2021-07-07 Knud Thomsen

Most approaches to quantum gravity suggest that relativistic spacetime is not fundamental, but instead emerges from some non-spatiotemporal structure. This paper investigates the implications of this suggestion for the possibility of time…

History and Philosophy of Physics · Physics 2019-07-26 Christian Wuthrich

We live in a 3+1 space-time that is intended as a description of the universe with three space dimensions and one time dimension. Space-time dimensionality seems so natural that it is rarely criticized. Experiments and the highly successful…

General Physics · Physics 2009-11-10 Giorgio Fontana

Despite being a major component in the teaching of special relativity, the twin `paradox' is generally not examined in courses on general relativity. Due to the complexity of analytical solutions to the problem, the paradox is often…

General Relativity and Quantum Cosmology · Physics 2016-08-03 Kenneth K. H. Fung , Hamish A. Clark , Geraint F. Lewis , Xiaofeng Wu

In order to respect the Principle of Relativity, the analysis of the behavior of the longitudinal light clock reveals the necessity to extend the Doppler effect also to space and time. As a consequence, the bodies in inertial motion must…

General Physics · Physics 2015-11-16 Giovanni Zanella

Entangled states of light exhibit measurable correlations between light detections at separated locations. These correlations are exploited in entangled-state quantum key distribution. To do so involves setting up and maintaining a rhythm…

Quantum Physics · Physics 2020-04-27 F. Hadi Madjid , John M. Myers

We present a novel derivation of both the Minkowski metric and Lorentz transformations from the consistent quantification of a causally ordered set of events with respect to an embedded observer. Unlike past derivations, which have relied…

Mathematical Physics · Physics 2014-12-22 Kevin H. Knuth , Newshaw Bahreyni

The Classical Twin Paradox is widely dealt in literature and neatly resolved. In addition, it is also well known that, when looking at two systems which are boosted relative to each other, the concept of the simultaneous effect of a quantum…

General Relativity and Quantum Cosmology · Physics 2011-02-10 Doron ludwin

All the relativistic cosmological models of the universe, except Einstein's static model, imply that the 3-space of the spacetime of the universe is also expanding apart from the matter and the radiation in it. However, there is no…

General Physics · Physics 2009-01-15 R. K. Thakur