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In this work we present a discussion of the existing links between the procedures of endowing the quantum gravity with a real time and of including in the theory a physical reference frame. More precisely, as first step, we develop the…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Simone Mercuri , Giovanni Montani

With the birth of quantum information science, many tools have been developed to deal with many-body quantum systems. Although a complete description of such systems is desirable, it will not always be possible to achieve this goal, as the…

Quantum Physics · Physics 2020-12-01 Cristhiano Duarte , Barbara Amaral , Marcelo Terra Cunha , Matthew Leifer

We explore the structure of the spin foam-like vertex expansion in loop quantum cosmology and discuss properties of the corresponding amplitudes, with the aim of elucidating some of the expansion's useful properties and features. We find…

General Relativity and Quantum Cosmology · Physics 2017-03-16 David A. Craig , Parampreet Singh

Constrained Hamiltonian dynamics of a quantum system of nonlinear oscillators is used to provide the mathematical formulation of a coarse-grained description of the quantum system. It is seen that the evolution of the coarse-grained system…

Quantum Physics · Physics 2015-05-28 Milan Radonjić , Slobodan Prvanović , Nikola Burić

A general formalism of the spin quantum entanglement in a curved space-time represented. As examples Kerr and non commutative Reissner- Nordstr\"om models are considered. The behaviors of the concurrence and entanglement entropy as a…

General Relativity and Quantum Cosmology · Physics 2020-02-20 A. Mohadi , N. Mebarki , M. Boussahel

According to standard quantum theory, the time evolution operator of a quantum system is independent of the state of the system. One can, however, consider systems in which this is not the case: the evolution operator may depend on the…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Domokos , S. Kovesi-Domokos

In this work we study an inverse dynamical problem for a bipartite quantum system governed by the time local master equation: to find the class of generators which give rise to a certain time evolution with the constraint of fixed reduced…

Quantum Physics · Physics 2020-11-19 Giuseppe Baio , Dariusz Chruscinski , Antonino Messina

A 3+1 spacetime, with a shift vector that is the unique fundamental solution to the linearized wave operator, is introduced to model an interpretation of Wheeler's layman's analogy of the Quantum foam. To understand the distributional…

General Relativity and Quantum Cosmology · Physics 2023-05-30 Claes Cramer

Spin foams arose as the covariant (path integral) formulation of quantum gravity depicting transition amplitudes between different quantum geometry states. As such, they provide a scheme to study the no boundary proposal, specifically the…

General Relativity and Quantum Cosmology · Physics 2024-07-30 Joseph Bunao , Pietropaolo Frisoni , Athanasios Kogios , Jared Wogan

In this article the time evolution operator of two interacting quantum oscillators, whose Hamiltonian is an element of the complex $\left\{ h(1) \oplus h(1) \right\} \uplus u(2)$ algebra, is analyzed using the Feynman time ordering operator…

Quantum Physics · Physics 2023-07-20 Nibaldo-Edmundo Alvarez-Moraga

We study the time evolution of a state of a relativistic quantum field theory restricted to a spatial subregion $\Omega$. More precisely, we use the Feynman-Vernon influence functional formalism to describe the dynamics of the field theory…

High Energy Physics - Theory · Physics 2025-01-03 Markus Schröfl , Stefan Floerchinger

Evolutional entanglement production is defined as the amount of entanglement produced by the evolution operator. This quantity is analyzed for systems whose Hamiltonians are characterized by spin operators. The evolutional entanglement…

Quantum Physics · Physics 2015-12-09 V. I. Yukalov , E. P. Yukalova

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

Time dependent quantum systems have become indispensable in science and its applications, particularly at the atomic and molecular levels. Here, we discuss the approximation of closed time dependent quantum systems on bounded domains, via…

Analysis of PDEs · Mathematics 2017-09-19 Joseph W. Jerome

A quantum clock cannot be modeled as a point mass moving along a single geodesic if it is in a state with nonzero position fluctuations. Instead, it is an extended object subject to tidal forces and a superposition of time dilations at…

Quantum Physics · Physics 2025-03-11 Joseph Balsells , Martin Bojowald

The concept of space-evolution (or space-time duality) has emerged as a promising approach for studying quantum dynamics. The basic idea involves exchanging the roles of space and time, evolving the system using a space transfer matrix…

Quantum Physics · Physics 2023-11-03 Alessandro Foligno , Tianci Zhou , Bruno Bertini

Discrete models usually represent approximations to continuum physics. Cylindrical consistency provides a framework in which discretizations mirror exactly the continuum limit. Being a standard tool for the kinematics of loop quantum…

General Relativity and Quantum Cosmology · Physics 2015-06-05 Bianca Dittrich

Quintessence issues can be achieved by taking into account higher order curvature invariants into the effective action of gravitational field. Such an approach is naturally related to fundamental theories of quantum gravity which predict…

Astrophysics · Physics 2009-11-10 S. Capozziello , V. F. Cardone , S. Carloni , A. Troisi

We introduce a general construction of master equations with memory kernel whose solutions are given by completely positive trace preserving maps. These dynamics going beyond the Lindblad paradigm are obtained with reference to classical…

Quantum Physics · Physics 2020-06-18 Bassano Vacchini

It is proposed that spacetime should be regarded as an evolving block universe, bounded to the future by the present time, which continually extends to the future. This future boundary is defined at each time by measuring proper time along…

General Relativity and Quantum Cosmology · Physics 2015-06-22 George F R Ellis