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Related papers: Arrow(s) of Time without a Past Hypothesis

200 papers

We present an exact relationship between the entropy production and the distinguishability of a process from its time-reverse, quantified by the relative entropy between forward and backward states. The relationship is shown to remain valid…

Statistical Mechanics · Physics 2017-05-15 Juan M. R. Parrondo , Christian van den Broeck , Ryoichi Kawai

In the absence of an external frame of reference physical degrees of freedom must describe relations between systems. Using a simple model, we investigate how such a relational quantum theory naturally arises by promoting reference systems…

Quantum Physics · Physics 2009-11-11 David Poulin

Most existing proposals to explain the temporal asymmetries we see around us are sited within an approach to physics based on time evolution, and thus they typically put the asymmetry in at the beginning of time in the form of a special…

History and Philosophy of Physics · Physics 2023-07-06 Emily Adlam

How does the arrow of time (dissipative, irreversible behavior) emerge from time-reversible Hamiltonian mechanics? Two ingredients are needed: the underlying system must be ergodic or phase-mixing, and our knowledge of the system must be…

Statistical Mechanics · Physics 2026-03-24 Katerina Mlada , Michal Pavelka , Vaclav Klika

A dynamical estimate is given for the Boltzmann entropy of the Universe, under the simplifying assumptions provided by Newtonian cosmology. We first model the cosmological fluid as the probability fluid of a quantum-mechanical system. Next,…

Quantum Physics · Physics 2023-07-19 D. Cabrera , P. Fernandez de Cordoba , J. M. Isidro

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

All of the basic microsopic physical laws are time reversible. In contrast, the second law of thermodynamics, which is a macroscopic physical representation of the world, is able to describe irreversible processes in an isolated system…

Chemical Physics · Physics 2015-06-19 Roland Riek

The framework of a theory of gravity from the quantum to the classical regime is presented. The paradigm shift from full spacetime covariance to spatial diffeomorphism invariance, together with clean decomposition of the canonical…

General Relativity and Quantum Cosmology · Physics 2019-12-06 Chopin Soo , Hoi-Lai Yu

Are your perceptions, memories and observational data, a statistical fluctuation out of the thermal equilibrium of the universe, having no correlation with the actual past state of the universe? Arguments are given in the literature for and…

History and Philosophy of Physics · Physics 2026-01-26 David Wolpert , Carlo Rovelli , Jordan Scharnhorst

This paper presents alternative ideas on the physics of time that lead to a new interpretation of cosmological redshifts. These ideas are based on the close relationship between the speed of time and entropy processes in our universe. I…

Astrophysics · Physics 2009-11-06 Vladimir I. Garaimov

The concept of time series irreversibility -- the degree by which the statistics of signals are not invariant under time reversal -- naturally appears in non-equilibrium physics in stationary systems which operate away from equilibrium and…

Physics and Society · Physics 2020-08-05 Alfredo González-Espinoza , Gustavo Martínez-Mekler , Lucas Lacasa

We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional gauge theory methods fail to capture the full classical…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Sean Gryb , Karim Thebault

It is shown in the framework of a harmonic system that the thermodynamical time arrow is induced by the environmental initial conditions in a manner similar to spontaneous symmetry breaking. The Closed Time Path formalism is introduced in…

Quantum Physics · Physics 2015-06-11 Janos Polonyi

The spontaneous violation of Lorentz and diffeomorphism invariance in a phase near the big bang lowers the entropy, allowing for an arrow of time and the second law of thermodynamics. The spontaneous symmetry breaking leads to…

General Relativity and Quantum Cosmology · Physics 2016-03-08 J. W. Moffat

We develop the framework of classical Observational entropy, which is a mathematically rigorous and precise framework for non-equilibrium thermodynamics, explicitly defined in terms of a set of observables. Observational entropy can be seen…

Statistical Mechanics · Physics 2020-09-09 Dominik Šafránek , Anthony Aguirre , J. M. Deutsch

The definition of thermodynamic entropy is dependent on one's assignment of physical microstates to observed macrostates. As a result, low entropy in the distant past could be equivalently explained by selection of a particular observer. In…

High Energy Physics - Theory · Physics 2024-05-22 Brendon Matusch

Causality underpins all logical reasoning. However, the causal structure in quantum processes can be far from intuitive, often differing from its classical counterpart in relativity, which is defined by the light cone. In particular, in…

Quantum Physics · Physics 2026-01-21 Hong-Yi Wang , Haifeng Tang , Xiao-Liang Qi

Statistical physics cannot explain why a thermodynamic arrow of time exists, unless one postulates very special and unnatural initial conditions. Yet, we argue that statistical physics can explain why the thermodynamic arrow of time is…

General Physics · Physics 2012-10-10 Oleg Kupervasser , Hrvoje Nikolić , Vinko Zlatić

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

This paper is a continuation of the paper gr-qc/0203045 and is devoted to the problem of the arrow of time. A deterministic past-directed dynamics is constructed, which results in the retrodictive universe. A future-directed dynamics of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Vladimir S. Mashkevich