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Related papers: Time as a Cosmological Phenomenon

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Nonmetricity derived from a scalar field is shown to exist as a cosmic field, without direct coupling to matter. It leads to a variable cosmological term, a term that dominates the expansion in the early universe but dies away at later…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Richard T Hammond

We basis our initial analysis of the arrow of time on a relationship between the time evolution operator of quantum system and the time-independent density operator which describes the equilibrium state of a many-particle system at…

General Relativity and Quantum Cosmology · Physics 2023-04-05 Benno Bodmann , César A. Zen Vasconcellos , José de Freitas Pacheco , Peter O. Hess , Dimiter Hadjimichef

It is shown that (special) relativistically dilated time is the vector sum of rest time and time induced by movement in three dimensional space exeeding the rest time component and that the first vector is orthogonally directed relative to…

General Physics · Physics 2007-05-23 Ernst Karl Kunst

Questions such as whether we live in a spatially finite universe, and what its shape and size may be, are among the fundamental open problems that high precision modern cosmology needs to resolve. These questions go beyond the scope of…

Astrophysics · Physics 2007-05-23 M. J. Reboucas , G. I. Gomero

Space and time are central concepts for understanding our World. They are important ingredients at the core of every scientific theory and subject of intense debate in philosophy. Albert Einstein's Special and General theories of Relativity…

History and Philosophy of Physics · Physics 2021-08-06 Luciano Combi

There are theories which implement the idea that the constants of nature may be "time dependent." These introduce new fields representing "evolving constants," in addition to physical fields. We argue that dynamical matter coupling…

General Relativity and Quantum Cosmology · Physics 2018-07-27 Syed Moeez Hassan , Viqar Husain , Babar Qureshi

It is proposed that spacetime should be regarded as an evolving block universe, bounded to the future by the present time, which continually extends to the future. This future boundary is defined at each time by measuring proper time along…

General Relativity and Quantum Cosmology · Physics 2015-06-22 George F R Ellis

We investigate three aspects of the supposed problem of time: The disagreement between the treatments of time in general relativity and quantum theory, the problem of recovering time from within an isolated Universe and the prevalence of a…

Quantum Physics · Physics 2018-11-27 K. L. H. Bryan , A. J. M. Medved

Our universe seems to be radiation dominated at early times, and vacuum energy dominated at late times. When we consider the maximal analytic extension of this spacetime, its symmetries and complex analytic properties suggest a picture in…

High Energy Physics - Theory · Physics 2021-09-15 Latham Boyle , Neil Turok

All differences between the role of space and time in nature are explained by proposing the principles in which none of the spacetime coordinates has an {\it a priori} special role. Spacetime is treated as a non-dynamical manifold, with a…

General Relativity and Quantum Cosmology · Physics 2023-04-25 Hrvoje Nikolic

Most attempts to argue for the second law of thermodynamics fail because (1) they use the unviable frequency theory of probability and (2) they do not explain why the arrow of time seen in experiments is aligned with the thermodynamic arrow…

Quantum Physics · Physics 2008-11-24 Alan Forrester

It is argued that the observed Thermodynamic Arrow of Time must arise from the boundary conditions of the universe. We analyse the consequences of the no boundary proposal, the only reasonably complete set of boundary conditions that has…

General Relativity and Quantum Cosmology · Physics 2009-10-22 S. W. Hawking , R. Laflamme , G. W. Lyons

We consider cosmological consequences of a conformal-invariant unified theory which is dynamically equivalent to general relativity and is given in a space with the geometry of similarity. We show that the conformal-invariant theory offers…

General Relativity and Quantum Cosmology · Physics 2007-05-23 D. Behnke , D. Blaschke , V. Pervushin , D. Proskurin , A. Zakharov

A new approach is suggested to the problem of quantising causal sets, or topologies, or other such models for space-time (or space). The starting point is the observation that entities of this type can be regarded as objects in a category…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. J. Isham

We describe a link between the cosmological constant problem and the problem of time in quantum gravity. This arises by examining the relationship between the cosmological constant and vacuum energy in light of non-perturbative formulations…

General Relativity and Quantum Cosmology · Physics 2010-03-12 Viqar Husain

We point out that time's arrow is naturally induced by quantum mechanical evolution, whenever the systems have a very large number ${\cal N}$ of non-degenerate states and a Hamiltonian bounded from below. When ${\cal N}$ is finite, the…

High Energy Physics - Theory · Physics 2024-07-03 Nemanja Kaloper

The only widely accepted explanation for the various arrows of time that everywhere and at all epochs point in the same direction is the `past hypothesis': the Universe had a very special low-entropy initial state. We present the first…

General Relativity and Quantum Cosmology · Physics 2014-12-11 Julian Barbour , Tim Koslowski , Flavio Mercati

According to Aristotle "time is the number of change with respect to the before and after". That's certainly a vague concept, but at the same time it's both simple and satisfying from a philosophical point of view: things do not change…

History and Philosophy of Physics · Physics 2022-01-07 Marcello Poletti

The idea that the cosmological term, Lambda, should be a time dependent quantity in cosmology is a most natural one. It is difficult to conceive an expanding universe with a strictly constant vacuum energy density, namely one that has…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Joan Sola

In this paper we discuss a possible cosmological time evolution of fundamental constants from the theoretical and experimental point of views. On the theoretical side, we explain that such a cosmological time evolution is actually something…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Xavier Calmet , Matthias Keller