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Related papers: Janus Points and Arrows of Time

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In contrast to claims by Barbour, Koslowski and Mercati, their "Janus point solution" does require a very improbable selection condition. While gravitational contraction in an expanding universe may then represent the master arrow of time,…

General Relativity and Quantum Cosmology · Physics 2016-01-13 H. Dieter Zeh

In any physical theory that admits true indeterminism, the thermodynamic arrow of time can arise regardless of the system's initial conditions. Hence on such theories time's arrow emerges out of the basic physical interactions. The example…

Quantum Physics · Physics 2007-05-23 Shahar Dolev , Avshalom C. Elitzur , Meir Hemmo

Entropy and the second law of thermodynamcs were discovered through study of the behaviour of gases in confined spaces. The related techniques developed in the kinetic theory of gases have failed to resolve the apparent conflict between the…

General Relativity and Quantum Cosmology · Physics 2016-02-26 Julian Barbour

The spread of the time arrows from the environment to an observed subsystem is followed within a harmonic model. A similarity is pointed out between irreversibility and a phase with spontaneously broken symmetry. The causal structure of…

High Energy Physics - Theory · Physics 2012-06-26 Janos Polonyi

The existence of a thermodynamic arrow of time in the present universe implies that the initial state of the observable portion of our universe at (or near) the ``big bang'' must have been very ``special''. We argue that it is not plausible…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Robert M. Wald

It is brought forward that viable theories of the physical world that have no variable at all that can play the role of time, do not exist; some notion of time is one of the very first ingredients a candidate theory should possess. Almost…

Quantum Physics · Physics 2018-04-05 Gerard t Hooft

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

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

We discuss the arrow of time in terms of the increase of correlations between the system and its environment. Here we show that the existence of the arrow of time, based on deleting correlations, requires a strict absence of initial…

Quantum Physics · Physics 2016-05-04 Vlatko Vedral

We derive the arrows of time of our universe that follow from the no-boundary theory of its quantum state (NBWF) in a minisuperspace model. Arrows of time are viewed four-dimensionally as properties of the four-dimensional Lorentzian…

High Energy Physics - Theory · Physics 2013-09-04 James Hartle , Thomas Hertog

The arrow of time is an irreversible phenomenon for a system of particles undergoing reversible dynamics. Since the time of Boltzmann to this day, the arrow of time has led to debate and research. However, the enormous growth of…

Statistical Mechanics · Physics 2020-07-22 Derek Wright , Roshan Klein-Seetharaman , Susanta K. Sarkar

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

One of the most difficult problems in the foundations of physics is what gives rise to the arrow of time. Since the fundamental dynamical laws of physics are (essentially) symmetric in time, the explanation for time's arrow must come from…

History and Philosophy of Physics · Physics 2021-10-26 Eddy Keming Chen

Living systems are fundamentally irreversible, breaking detailed balance and establishing an arrow of time. But how does the evident arrow of time for a whole system arise from the interactions among its multiple elements? We show that the…

Statistical Mechanics · Physics 2022-09-21 Christopher W. Lynn , Caroline M. Holmes , William Bialek , David J. Schwab

Although most fundamental laws are invariant under time reversal, experience exhibits the presence of irreversible phenomena -- the arrows of time. Their origin lies in cosmology, and I argue that only quantum cosmology can provide the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Claus Kiefer

We investigate the statistical arrow of time for a quantum system being monitored by a sequence of measurements. For a continuous qubit measurement example, we demonstrate that time-reversed evolution is always physically possible, provided…

Quantum Physics · Physics 2017-12-06 Justin Dressel , Areeya Chantasri , Andrew N. Jordan , Alexander N. Korotkov

We prove that a time series satisfying a (linear) multivariate autoregressive moving average (VARMA) model satisfies the same model assumption in the reversed time direction, too, if all innovations are normally distributed. This…

Statistics Theory · Mathematics 2016-03-03 Stefan Bauer , Bernhard Schölkopf , Jonas Peters

Existing accounts of the cosmological arrow of time face a dilemma: generalist approaches that posit time-asymmetric laws lack independent motivation, while particularist approaches that invoke a Past Hypothesis face serious conceptual and…

History and Philosophy of Physics · Physics 2025-10-06 Sean Gryb , Simon Friederich

A model quantum cosmology is used to illustrate how arrows of time emerge in a universe governed by a time-neutral dynamical theory constrained by time asymmetric initial and final boundary conditions represented by initial and final…

General Relativity and Quantum Cosmology · Physics 2020-02-18 James B. Hartle

The direct and indirect experimental proofs of a strong time invariance violation in optics are discussed. Time noninvariance for present day becomes the only real physical base for explanation the origin of the most phenomena in nonlinear…

General Physics · Physics 2007-05-23 Vladimir A. Kuz'menko
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