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Related papers: Cosmology, Time's Arrow, and That Old Double Stand…

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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 motion and on the strength of the…

General Relativity and Quantum Cosmology · Physics 2017-07-25 Hauret Clementine , Magain Pierre , Biernaux Judith

In this paper we address the problem of the arrow of time from a cosmological point of view, rejecting the traditional entropic approach that defines the future direction of time as the direction of the entropy increase: from our…

Quantum Physics · Physics 2009-11-07 Mario Castagnino , Luis Lara , Olimpia Lombardi

This thesis addresses two major problems in the philosophy of physics. The first is how to identify the minimal physical content of a theory; that is, what features of a theory are truly needed to make predictions, and what can be removed…

History and Philosophy of Physics · Physics 2025-09-19 Sean Gryb

The second law of thermodynamics is asymmetric with respect to time as it says that the entropy of the universe must have been lower in the past and will be higher in the future. How this time-asymmetric law arises from the time-symmetric…

Statistical Mechanics · Physics 2021-06-07 Sivapalan Chelvaniththilan

Time is a parameter playing a central role in our most fundamental modeling 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 2015-05-11 Pierre Magain , Clémentine Hauret

On the orthodox interpretation of bounce cosmologies, a preceding universe was compressed to a small size before ``bouncing'' to form the present expanding universe. William Lane Craig and James Sinclair have argued that the orthodox…

History and Philosophy of Physics · Physics 2020-06-16 Daniel Linford

If an asymmetry in time does not arise from the fundamental dynamical laws of physics, it may be found in special boundary conditions. The argument normally goes that since thermodynamic entropy in the past is lower than in the future…

Quantum Physics · Physics 2024-07-23 Jim Al-Khalili , Eddy Keming Chen

There is a paradox in the standard model of cosmology. How can matter in the early universe have been in thermal equilibrium, indicating maximum entropy, but the initial state also have been low entropy (the "past hypothesis"), so as to…

General Relativity and Quantum Cosmology · Physics 2023-12-21 Jordan Scharnhorst , Anthony Aguirre

The classical evolution of the universe can be seen as a parametrised worldline of the minisuperspace, with the time variable $t$ the parameter that parametrises the worldline. The time reversal symmetry of the field equations implies that…

General Relativity and Quantum Cosmology · Physics 2019-10-17 Salvador J. Robles-Perez

I discuss how modern cosmology illustrates under-determination of theoretical hypotheses by data, in ways that are different from most philosophical discussions. I emphasize cosmology's concern with what data could in principle be collected…

History and Philosophy of Physics · Physics 2014-06-19 Jeremy Butterfield

We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Genly Leon , Emmanuel N. Saridakis

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

We provide a discussion of some main ideas in our project about the physical foundation of the time concept in cosmology. It is standard to point to the Planck scale (located at $\sim 10^{-43}$ seconds after a fictitious "Big Bang" point)…

General Relativity and Quantum Cosmology · Physics 2016-03-18 Svend E. Rugh , Henrik Zinkernagel

This thesis deals with the averaging problem in cosmology, which has gained considerable interest in recent years, and is concerned with correction terms (after averaging inhomogeneities) that appear in the Einstein equations when working…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-06 Aseem Paranjape

In this paper I suggest a possible explanation for the asymmetry of time. In the case that I study, the dynamical laws and the boundary conditions are symmetric, but the behavior of time is not. The underlying mechanism is statistical and…

General Physics · Physics 2014-07-23 Martin Tamm

While the basic laws of physics seem time-reversal invariant, our understanding of the apparent irreversibility of the macroscopic world is well grounded in the notion of entropy. Because astrophysics deals with the largest structures in…

General Physics · Physics 2015-07-30 David Garofalo

We discuss the cosmological constant problem in the light of dilatation symmetry and its possible anomaly. For dilatation symmetric quantum theories realistic asymptotic cosmology is obtained provided the effective potential has a…

High Energy Physics - Theory · Physics 2017-11-13 C. Wetterich

Microphysical laws are time reversible, but macrophysics, chemistry and biology are not. This chapter explores how this asymmetry (a classic example of a broken symmetry) arises due to the cosmological context, where a non-local Direction…

General Relativity and Quantum Cosmology · Physics 2020-03-18 George F R Ellis , Barbara Drossel

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

It is argued that some of the recent claims for cosmology are grossly overblown. Cosmology rests on a very small database: it suffers from many fundamental difficulties as a science (if it is a science at all) whilst observations of distant…

Astrophysics · Physics 2008-11-26 M. J. Disney
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