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Related papers: Realistic clocks for a Universe without time

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In this paper, we present a proof-of-concept quantum algorithm for simulating time-dependent Hamiltonian evolution by reducing the problem to simulating a time-independent Hamiltonian in a larger space using a discrete clock Hamiltonian…

Quantum Physics · Physics 2025-07-28 Zecheng Li , Chunhao Wang

We study the dynamical evolution of two quantum clocks interacting with a relativistic gravitational potential. We find a time dilation effect for the clocks in agreement with the gravitational time dilation as obtained from the…

General Relativity and Quantum Cosmology · Physics 2025-05-02 Tommaso Favalli , Augusto Smerzi

We show that the usual Born-Oppenheimer type of approximation used in quantum gravity, in which a semiclassical time parameter emerges from a weak-coupling expansion of the Wheeler-DeWitt constraint, leads to a unitary theory at least up to…

General Relativity and Quantum Cosmology · Physics 2022-05-20 Leonardo Chataignier

Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-05 Pierre Magain , Clémentine Hauret

We give an explicit, rigorous framework for calculating quantum probabilities in a model theory of quantum gravity. Specifically, we construct the decoherence functional for the Wheeler-DeWitt quantization of a flat…

General Relativity and Quantum Cosmology · Physics 2011-01-20 David A. Craig , Parampreet Singh

After a brief introduction to issues that plague the realization of a theory of quantum gravity, I suggest that the main one concerns a quantization of the principle of relative simultaneity. This leads me to a distinction between time and…

Quantum Physics · Physics 2018-05-07 Henrique de A. Gomes

We present a novel theory of the very early universe which addresses the traditional horizon and flatness problems of big bang cosmology and predicts a scale invariant spectrum of perturbations. Unlike inflation, this scenario requires no…

High Energy Physics - Theory · Physics 2012-04-24 Kurt Hinterbichler , Justin Khoury

In earlier papers we showed unpredictability beyond quantum uncertainty in atomic clocks, ensuing from a proven gap between given evidence and explanations of that evidence. Here we reconceive a clock, not as an isolated entity, but as…

Quantum Physics · Physics 2015-04-17 F. Hadi Madjid , John M. Myers

For a quantum scalar field that is confined in a uniformly linearly accelerated cavity in Minkowski spacetime and interacts linearly with a scalar field that is not confined in the cavity, a de-excitation probability formula was obtained in…

General Relativity and Quantum Cosmology · Physics 2026-04-09 Krzysztof Lorek , Jorma Louko , Andrzej Dragan

Understanding different aspects of time is at the core of many areas in theoretical physics. Minimal models of continuous stochastic and quantum clocks have been proposed to explore fundamental limitations on the performance of timekeeping…

Quantum Physics · Physics 2026-03-31 Ludmila Viotti , Marcus Huber , Rosario Fazio , Gonzalo Manzano

In previous works, we showed that both time and space can emerge from entanglement within a globally constrained quantum Universe, with no background coordinates. By extending the Page and Wootters quantum time formalism to include both…

General Relativity and Quantum Cosmology · Physics 2025-09-30 Tommaso Favalli

We make a first attempt to axiomatically formulate the Montevideo interpretation of quantum mechanics. In this interpretation environmental decoherence is supplemented with loss of coherence due to the use of realistic clocks to measure…

Quantum Physics · Physics 2012-02-13 Rodolfo Gambini , Luis Pedro Garcia-Pintos , Jorge Pullin

Strategies intended to resolve the problem of time in quantum gravity by means of emergent or hidden timefunctions are considered in the arena of relational particle toy models. In situations with `heavy' and `light' degrees of freedom, two…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Edward Anderson

In this paper I argue for a reassessment of special relativity. The fundamental theory of relativity applicable in this Universe has to be consistent with the existence of the massive Universe, and with the effects of its gravitational…

General Relativity and Quantum Cosmology · Physics 2007-05-23 C. S. Unnikrishnan

The problem of time in canonical quantum gravity remains one of the most significant challenges, primarily due to the "frozen" formalism emerging from the Wheeler-DeWitt equation. Within the ADM formalism, we introduce a novel approach in…

General Relativity and Quantum Cosmology · Physics 2025-12-02 Pradosh Keshav MV

We analyze the nature and performance of clocks formed by stabilizing an oscillator to the phase difference between two paths of an atom interferometer. The phase evolution has been modeled as being driven by the proper-time difference…

Atomic Physics · Physics 2014-02-27 Steven Peil , Christopher R. Ekstrom

I propose a new class of interpretations, {\it real world interpretations}, of the quantum theory of closed systems. These interpretations postulate a preferred factorization of Hilbert space and preferred projective measurements on one…

Quantum Physics · Physics 2012-02-24 Adrian Kent

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

Based on Newton's laws reformulated in the Hamiltonian dynamics combined with statistical mechanics, we formulate a statistical mechanical theory supporting the hypothesis of a closed oscillating universe. We find that the behaviour of the…

Statistical Mechanics · Physics 2015-05-13 A. Perez-Madrid , I. Santamaria-Holek

The problem of time in quantum gravity calls for a relational solution. Using quantum reduction maps, we establish a previously unknown equivalence between three approaches to relational quantum dynamics: 1) relational observables in the…

Quantum Physics · Physics 2021-09-08 Philipp A. Hoehn , Alexander R. H. Smith , Maximilian P. E. Lock