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Related papers: Extrinsic Time in Quantum Cosmology

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We propose a class of theories that can limit scalars constructed from the extrinsic curvature. Applied to cosmology, this framework allows us to control not only the Hubble parameter but also anisotropies without the problem of…

General Relativity and Quantum Cosmology · Physics 2020-10-06 Yuki Sakakihara , Daisuke Yoshida , Kazufumi Takahashi , Jerome Quintin

Einstein's theory of general relativity is based on the premise that the physical laws take the same form in all coordinate systems. However, it still presumes a preferred decomposition of the total kinematic Hilbert space into local…

General Relativity and Quantum Cosmology · Physics 2021-04-28 Sung-Sik Lee

The use of a relational time in quantum mechanics is a framework in which one promotes to quantum operators all variables in a system, and later chooses one of the variables to operate like a ``clock''. Conditional probabilities are…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Rodolfo Gambini , Rafael Porto , Jorge Pullin

By considering (non-relativistic) quantum mechanics as it is done in practice in particular in condensed-matter physics, it is argued that a deterministic, unitary time evolution within a chosen Hilbert space always has a limited scope,…

Quantum Physics · Physics 2017-10-03 Barbara Drossel

Space-time--time is a natural hybrid of Kaluza's five-dimensional geometry and Weyl's conformal space-time geometry. Translations along the secondary time dimension produce the electromagnetic gauge transformations of Kaluza--Klein theory…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Homer G. Ellis

Besides the purely digital or analog interpretation of reality there is a third possibility which incorporates important aspects of both. This is the cyclic formulation of elementary systems, in which elementary particles are represented as…

General Relativity and Quantum Cosmology · Physics 2012-05-09 Donatello Dolce

Given the lack of an absolute time parameter in general relativistic systems, quantum cosmology often describes the expansion of the universe in terms of relational changes between two degrees of freedom, such as matter and geometry.…

General Relativity and Quantum Cosmology · Physics 2023-10-16 Luis Martinez , Martin Bojowald , Garrett Wendel

We investigate quantum mechanical Hamiltonians with explicit time dependence. We find a class of models in which an analogue of the time independent \S equation exists. Among the models in this class is a new exactly soluble model, the…

High Energy Physics - Theory · Physics 2009-10-22 John Rogers , Donald Spector

We begin this work calculating Halliwell's propagator in the case of a Mixmaster universe with small anisotropy. Afterwards in the context of the Decoherence Model we introduce in our system terms that comprise the self-measurement of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 A. Camacho , A. Camacho-Galvan

Quantum Geometrodynamics with intrinsic time development and momentric variables is presented. An underlying SU(3) group structure at each spatial point regulates the theory. The intrinsic time behavior of the theory is analyzed, together…

General Relativity and Quantum Cosmology · Physics 2015-08-12 Eyo Eyo Ita , Chopin Soo , Hoi-Lai Yu

Time ordering may be defined by first defining the limit of no time ordering (NTO) in terms of a time average of an external interaction, V(t). Previously, time correlation was defined in terms of a similar limit called the independent time…

The degree of freedom of the scalar field in scalar-tensor gravity is employed as "time" to deparametrize the Hamiltonian constraint of the theory. The deparametrized system is then nonperturbatively quantized by the approach of loop…

General Relativity and Quantum Cosmology · Physics 2026-03-02 Faqiang Yuan , Haida Li , Shengzhi Li , Yongge Ma

We provide a brief discussion regarding relativistic limits on the discretization and temporal resolution of time values in a quantum clock. Our clock is characterized by a time observable chosen to be the complement of a bounded and…

Quantum Physics · Physics 2025-10-16 Tommaso Favalli

We analyze the canonical quantum dynamics of the isotropic Universe in a metric approach by adopting a self-interacting scalar field as relational time. When the potential term is absent we are able to associate the the expanding and…

General Relativity and Quantum Cosmology · Physics 2023-09-15 Eleonora Giovannetti , Fabio Maione , Giovanni Montani

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

The problems encountered in trying to quantize the various cosmological models, are brought forward by means of a concrete example. The Automorphism groups are revealed as the key element through which G.C.T.'s can be used for a general…

General Relativity and Quantum Cosmology · Physics 2011-07-19 T. Christodoulakis

Time plays a crucial role in the intuitive understanding of the world around us. Within quantum mechanics, however, time is not usually treated as an observable quantity; it enters merely as a parameter in the laws of motion of physical…

Quantum Physics · Physics 2015-06-05 Sandra Ranković , Yeong-Cherng Liang , Renato Renner

Quantum mechanical unitarity in our universe is challenged both by the notion of the big bang, in which nothing transforms into something, and the expansion of space, in which something transforms into more something. This motivates the…

High Energy Physics - Theory · Physics 2022-02-08 Jordan Cotler , Andrew Strominger

Space-time symmetries and internal quantum symmetries can be placed on equal footing in a hyperspin geometry. Four-dimensional classical space-time emerges as a result of a decoherence that disentangles the quantum and the space-time…

Quantum Physics · Physics 2007-05-23 Dorje C. Brody , Lane P. Hughston

Thermal machines are physical systems designed to convert thermal energy into practical work through cyclic state transformations. A key component in such a machine is a clock-equipped control element that dictates which interaction…

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