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Related papers: Time's Arrow from the Multiverse Point of View

200 papers

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

The operational formulations of quantum theory are drastically time oriented. However, to the best of our knowledge, microscopic physics is time-symmetric. We address this tension by showing that the asymmetry of the operational…

Quantum Physics · Physics 2021-08-11 Andrea Di Biagio , Pietro Donà , Carlo Rovelli

Time-asymmetric behavior as embodied in the second law of thermodynamics is observed in {\it individual macroscopic} systems. It can be understood as arising naturally from time-symmetric microscopic laws when account is taken of a) the…

Statistical Mechanics · Physics 2007-09-06 Joel L. Lebowitz

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

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

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

In several previous papers we have argued for a global and non-entropic approach to the problem of the arrow of time, according to which the ''arrow'' is only a metaphorical way of expressing the geometrical time-asymmetry of the universe.…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Matias Aiello , Mario Castagnino , Olimpia Lombardi

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 familiar textbook quantum mechanics of laboratory measurements incorporates a quantum mechanical arrow of time --- the direction in time in which state vector reduction operates. This arrow is usually assumed to coincide with the…

Quantum Physics · Physics 2015-06-12 James B. Hartle

Collapse models are modifications of quantum theory where the wave function is treated as physically real and the collapse of the wave function is a physical process. This appears to introduce a time reversal asymmetry into the dynamics of…

Quantum Physics · Physics 2015-02-25 Daniel Bedingham , Owen Maroney

While the microscopic laws of physics are often symmetric under time reversal, most natural processes that we observe are not. The emergent asymmetry between typical and time-reversed processes is referred to as the arrow of time. In…

Quantum Physics · Physics 2025-12-23 Luis Pedro García-Pintos , Yi-Kai Liu , Alexey V. Gorshkov

It is widely accepted that temporal asymmetry is largely a cosmological problem; the task of explaining temporal asymmetry reduces in the main to that of explaining an aspect of the condition of the early universe. However, cosmologists who…

General Relativity and Quantum Cosmology · Physics 2009-09-25 Huw Price

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

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

The second law of thermodynamics - the usual statement of the arrow of time - has been called the most fundamental law of physics. It is thus difficult to conceive that a single dynamical system could contain subsystems, in significant…

Statistical Mechanics · Physics 2007-05-23 L. S. Schulman

In this paper we have studied a generalized quantum theory and its consistent classical limit, which possess a well-defined arrow of time in their dynamics. The original quantum theory is defined as analytically dependent on complex time…

High Energy Physics - Theory · Physics 2007-05-23 V. V. Asadov , O. V. Kechkin

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

An asymmetry exists between time and space in the sense that physical systems inevitably evolve over time whereas there is no corresponding ubiquitous translation over space. The asymmetry, which is presumed to be elemental, is represented…

Quantum Physics · Physics 2016-01-25 Joan A. Vaccaro

Conceptual problems regarding the arrow of time in classical physics, quantum physics, cosmology, and quantum gravity are discussed. Particular attention is paid to the dynamical role of the quantum indeterminism, and to various concepts of…

General Relativity and Quantum Cosmology · Physics 2012-07-30 H. D. Zeh

The evident contrast between the time symmetry of fundamental microscopic laws and the time asymmetry of macroscopic processes is a challenging physical problem. The observation of unitary evolution of a general physical system by an…

Statistical Mechanics · Physics 2022-02-24 Miroslav Holeček