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Related papers: Multiple choices of time in quantum cosmology

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We analize the relational quantum evolution of generally covariant systems in terms of Rovelli's evolving constants of motion and the generalized Heisenberg picture. In order to have a well defined evolution, and a consistent quantum…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Rodolfo Gambini , Rafael A. Porto

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

We discuss the question of time in a Bianchi I quantum cosmology in the framework of singularity avoidance. We show that time parameters fall into two distinct classes, that are such that the time development of the wave function either…

General Relativity and Quantum Cosmology · Physics 2020-02-18 Przemyslaw Malkiewicz , Patrick Peter , S. D. P. Vitenti

The local conservation of a physical quantity whose distribution changes with time is mathematically described by the continuity equation. The corresponding time parameter, however, is defined with respect to an idealized classical clock.…

Chemical Physics · Physics 2018-11-21 Axel Schild

The paper is intended to clarify operational meaning of mass and time quantities as main characteristics of an atomic clock, which is considered a quantum oscillator in association with the de Broglie wave concept. The specification of the…

Classical Physics · Physics 2007-05-23 Anatoli Vankov

A clock is, from an information-theoretic perspective, a system that emits information about time. One may therefore ask whether the theory of information imposes any constraints on the maximum precision of clocks. Here we show a…

Quantum Physics · Physics 2022-02-28 Mischa P. Woods , Ralph Silva , Gilles Pütz , Sandra Stupar , Renato Renner

In general relativity, the description of spacetime relies on idealised rods and clocks, which identify a reference frame. In any concrete scenario, reference frames are associated to physical systems, which are ultimately quantum in…

Quantum Physics · Physics 2021-07-28 Flaminia Giacomini

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

By allowing for non zero vacuum expectation values for some of the fields that appear in the Hamiltonian constraint of canonical general relativity a time variable, with usual properties, can be identified; the constraint plays the role of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Myron Bander

Global time is a gauge or relational choice of time variable in canonical gravity. Local time is the time used in a flat patch of spacetime. We compare the dynamics of a scalar field with respect to choices of global time and Minkowski…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Syed Moeez Hassan , Viqar Husain , Babar Qureshi

This paper puts forward a broad critical analysis of the concept of physical time. Clock effect is conceived as a consequence of the variation of the gravitational or pseudo gravitational potential, and it is remarked that only some real…

General Physics · Physics 2018-09-05 Claudio Borghi

The rules of quantum mechanics require a time coordinate for their formulation. However, a notion of time is in general possible only when a classical spacetime geometry exists. Such a geometry is itself produced by classical matter…

Quantum Physics · Physics 2007-05-23 T. P. Singh

There exists a stark tension among different formulations of quantum theory as some are inherently time-symmetric while others are time-asymmetric. This tension is crisply captured when considering physical theories as theories of…

Quantum Physics · Physics 2024-11-12 John H. Selby , Maria E. Stasinou , Stefano Gogioso , Bob Coecke

The landscape of causal relations that can hold among a set of systems in quantum theory is richer than in classical physics. In particular, a pair of time-ordered systems can be related as cause and effect or as the effects of a common…

Quantum Physics · Physics 2017-07-20 Katja Ried , Jean-Philippe W. MacLean , Robert W. Spekkens , Kevin J. Resch

We pursue the view that quantum theory may be an emergent structure related to large space-time scales. In particular, we consider classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Hans-Thomas Elze

In quantum systems, a plausible definition of work is based on two energy measurement scheme. Considering that energy change of quantum system obeys a time-energy uncertainty relation, it shall be interesting to see whether such type of…

Statistical Mechanics · Physics 2016-08-03 Fei Liu

We develop a systematic classical framework to accommodate canonical quantization of geometric and matter perturbations on a quantum homogeneous isotropic flat spacetime. The existing approach of standard cosmological perturbations is…

General Relativity and Quantum Cosmology · Physics 2013-06-05 Andrea Dapor , Jerzy Lewandowski , Jacek Puchta

We present a relational framework in which temporal structure is not fundamental but emerges from correlations within a globally stationary quantum state. Each subsystem includes an internal clock, and conditional states evolve effectively…

Quantum Physics · Physics 2025-12-19 Amir Hossein Ghasemi

Time plays different roles in quantum mechanics and gravity. These roles are examined and the problems that the conflict in the roles presents for quantum gravity are briefly summarised.

General Relativity and Quantum Cosmology · Physics 2008-02-03 W. G. Unruh

It is explained how the unification of resonance and decay phenomena into a consistent mathematical theory leads to quantum mechanical time-asymmetry. This provides the theoretical basis for a subsequent paper II in which the interpretation…

Quantum Physics · Physics 2007-05-23 A. Bohm , H. Kaldass , S. Komy
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