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Related papers: Cosmological Time, Entropy and Infinity

200 papers

According to the second law of thermodynamics, the arrow of time points to an ever increasing entropy of the Universe. However, exactly how the entropy evolves with time and what drives the growth remain largely unknown. Here, for the first…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-09 Xinghai Zhao , Yuexing Li , Qirong Zhu , Derek Fox

We find that the total entropy of the massive conformal gravity universe is an increasing function of time, and therefore the cosmological model of the theory passes the generalized second law of thermodynamics test.

General Physics · Physics 2025-05-26 F. F. Faria

It is generally believed that a cosmological arrow of time must be associated with entropy production. Indeed, in his seminal work on cyclic cosmology, Tolman introduced a viscous fluid in order to make successive expansion/contraction…

General Relativity and Quantum Cosmology · Physics 2018-10-26 Varun Sahni , Yuri Shtanov , Aleksey Toporensky

The arrow of time dilemma: the laws of physics are invariant for time inversion, whereas the familiar phenomena we see everyday are not (i.e. entropy increases). I show that, within a quantum mechanical framework, all phenomena which leave…

Quantum Physics · Physics 2010-04-22 Lorenzo Maccone

We discuss the emergence of time in quantum gravity, and ask whether time is always "something that flows"'. We first recall that this is indeed the case in both relativity and quantum mechanics, although in very different manners: time…

General Relativity and Quantum Cosmology · Physics 2012-04-10 Pierre Martinetti

We investigate the origin of the arrow of time in quantum mechanics in the context of quantum cosmology. The ``Copenhagen'' quantum mechanics of measured subsystems incorporates a fundamental arrow of time. Extending discussions of…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Murray Gell-Mann , James B. Hartle

This contribution analyses the classical laws of motion by means of an approach relating time and entropy. We argue that adopting the notion of change of states as opposed to the usual derivation of Newton's laws in terms of fields a…

General Physics · Physics 2007-06-19 R Assumpcao

In this manuscript we initiate a systematic examination of the physical basis for the time concept in cosmology. We discuss and defend the idea that the physical basis of the time concept is necessarily related to physical processes which…

General Relativity and Quantum Cosmology · Physics 2009-02-23 Svend Erik Rugh , Henrik Zinkernagel

We propose that physical time is based on counting the oscillations of wave functions. The discrete counting of the ticks of these clocks does not depend on the metric frame. It remains well defined for the beginning epochs of the universe.…

General Relativity and Quantum Cosmology · Physics 2024-08-06 Christof Wetterich

All clocks, in some form or another, use the evolution of nature towards higher entropy states to quantify the passage of time. Due to the statistical nature of the second law and corresponding entropy flows, fluctuations fundamentally…

Mesoscale and Nanoscale Physics · Physics 2021-05-12 A. N. Pearson , Y. Guryanova , P. Erker , E. A. Laird , G. A. D. Briggs , M. Huber , N. Ares

A fundamental description of time can be consistent not only with the usual monotonic behavior but also with a periodic physical clock variable, coupled to the degrees of freedom of a system evolving in time. Generically, one would in fact…

Quantum Physics · Physics 2022-05-25 Martin Bojowald , Luiz Martinez , Garrett Wendel

In the early seventies, Alan Sandage defined cosmology as the search for two numbers: Hubble parameter ${{H}_{0}}$ and deceleration parameter ${{q}_{0}}$. The first of the two basic cosmological parameters (the Hubble parameter) describes…

General Relativity and Quantum Cosmology · Physics 2015-07-01 Yu. L. Bolotin , V. A. Cherkaskiy , O. A. Lemets , D. A. Yerokhin , L. G. Zazunov

A hypothesis proposed in the paper (Entropy 2017, 19, 345) on the deductive formulation of a physical theory based on explicitly- and universally-introduced basic concepts is further developed. An entropic measure of time with a number of…

Statistical Mechanics · Physics 2019-03-27 Leonid M. Martyushev , Evgenii V. Shaiapin

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

The puzzle of the thermodynamic arrow of time reduces to the question of how the universe could have had lower entropy in the past. I show that no special entropy lowering mechanism (or fluctuation) is necessary. As a consequence of…

Statistical Mechanics · Physics 2015-05-13 L. S. Schulman

It is shown that the structures in the universe can be interpreted to show a closed wheel of time, rather than a straight arrow. An analysis in $f(R)$ gravity model has been carried out to show that due to local observations a small arc at…

General Physics · Physics 2018-01-26 Bal Krishna Yadav , Murli Manohar Verma

The arrow of time and the accelerated expansion are two fundamental empirical facts of the Universe. We advance the viewpoint that the dark energy (positive cosmological constant) accelerating the expansion of the Universe also supports the…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-20 A. E. Allahverdyan , V. G. Gurzadyan

Quantum gravity, the initial low entropy state of the Universe, and the problem of time are interlocking puzzles. In this article, we address the origin of the arrow of time from a cosmological perspective motivated by a novel approach to…

High Energy Physics - Theory · Physics 2015-06-04 Vishnu Jejjala , Michael Kavic , Djordje Minic , Chia-Hsiung Tze

The cosmological arrow of time may be linked to the thermodynamic arrow by second law of thermodynamics. The time asymmetry is also associated with dissipative fluid as Tolman introduced a viscous fluid to generate an arrow of time in…

General Physics · Physics 2016-07-21 Bal Krishna Yadav , Murli Manohar Verma

Arrows of time - thermodynamical, cosmological, electromagnetic, quantum mechanical, psychological - are basic properties of Nature. For a quantum system-bath closed system the de-correlated initial conditions and no-memory (Markovian)…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 V. G. Gurzadyan , S. Sargsyan , G. Yegorian