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We consider the evolution of quantum fields on a classical background space-time, formulated in the language of differential geometry. Time evolution along the worldlines of observers is described by parallel transport operators in an…

High Energy Physics - Theory · Physics 2007-05-23 Dirk Graudenz

Koopman operators and transfer operators represent nonlinear dynamics in state space through its induced action on linear spaces of observables and measures, respectively. This framework enables the use of linear operator theory for…

Dynamical Systems · Mathematics 2025-06-06 Claire Valva , Dimitrios Giannakis

We study the quantum fermions+gravity system, that is, the gravitational counterpart of QED. We start from the standard Einstein-Weyl theory, reformulated in terms of Ashtekar variables; and we construct its non- perturbative quantum theory…

General Relativity and Quantum Cosmology · Physics 2009-10-22 H A Marales-Tecotl , C Rovelli

A non-perturbative quantum field theory of General Relativity is presented which leads to a new realization of the theory of Covariant Quantum-Gravity (CQG-theory). The treatment is founded on the recently-identified Hamiltonian structure…

General Relativity and Quantum Cosmology · Physics 2017-05-24 Claudio Cremaschini , Massimo Tessarotto

It is remarkable that Heisenberg's position-momentum uncertainty relation leads to the existence of a maximal acceleration for a physical particle in the context of a geometric reformulation of quantum mechanics. It is also known that the…

Quantum Physics · Physics 2024-09-05 Paul M. Alsing , Carlo Cafaro

Quantum--mechanical operators corresponding to canonical momentum and position of a point--like particle, which follow from the quantum field theory in the general Riemannian space-time, satisfy generally to a deformation of the canonical…

General Relativity and Quantum Cosmology · Physics 2007-05-23 E. A. Tagirov

The Hamiltonian constraint remains an elusive object in loop quantum gravity because its action on spinnetworks leads to changes in their corresponding graphs. As a result, calculations in loop quantum gravity are often considered…

General Relativity and Quantum Cosmology · Physics 2025-07-28 Thiago L. M. Guedes , Guillermo A. Mena Marugán , Markus Müller , Francesca Vidotto

We present the problem of approximating the time-evolution operator $e^{-i\hat{H}t}$ to error $\epsilon$, where the Hamiltonian $\hat{H}=(\langle G|\otimes\hat{\mathcal{I}})\hat{U}(|G\rangle\otimes\hat{\mathcal{I}})$ is the projection of a…

Quantum Physics · Physics 2019-07-17 Guang Hao Low , Isaac L. Chuang

Quantum computation offers potential exponential speedups for simulating certain physical systems, but its application to nonlinear dynamics is inherently constrained by the requirement of unitary evolution. We propose the quantum Koopman…

Quantum Physics · Physics 2025-07-30 Baoyang Zhang , Zhen Lu , Yaomin Zhao , Yue Yang

In this paper we study the time evolution of an observable in the interacting fermion systems driven out of equilibrium. We present a method for solving the Heisenberg equations of motion by constructing excitation operators which are…

Strongly Correlated Electrons · Physics 2013-12-17 Pei Wang

With approaching quantum/noncommutative models for the deep microscopic spacetime in mind, and inspired by our recent picture of the (projective) Hilbert space as the model of physical space behind basic quantum mechanics, we reformulate…

Quantum Physics · Physics 2021-01-13 Chuan Sheng Chew , Otto C. W. Kong , Jason Payne

The quasi-Heisenberg picture of minisuperspace model is considered. The The quasi-Heisenberg picture of minisuperspace model is considered. The suggested scheme consists in quantizing of the equation of motion and interprets all observables…

General Relativity and Quantum Cosmology · Physics 2008-11-26 S. L. Cherkas , V. L. Kalashnikov

In this review, we focus on whether a canonical quantization of general relativity can produce testable predictions for cosmology. In particular, we examine how this approach can be used to model the evolution of primordial perturbations.…

General Relativity and Quantum Cosmology · Physics 2023-10-20 Leonardo Chataignier , Claus Kiefer , Paulo Moniz

The dynamics of open quantum systems is formulated in a minimally extended state space comprising the degrees of freedom of a system of interest and a finite set of non-unitary, pure-state reservoir modes. This formal structure, derived…

Quantum Physics · Physics 2023-08-01 Meng Xu , Vasilii Vadimov , Malte Krug , J. T. Stockburger , J. Ankerhold

The discretization approximation method commonly used to simulate the dynamics of quantum system coupled to the environment in continuum often suffers from the periodically partial recovery of initial state because of the effect of finite…

Quantum Physics · Physics 2025-05-07 H. T. Cui , Y. A. Yan , M. Qin , X. X. Yi

We describe a simple method for simulating time-independent Hamiltonian $H$ that could be decomposed as $H = \sum_{i=1}^m H_i$ where each $H_i$ can be efficiently simulated. Approaches relying on product formula generally work by splitting…

Quantum Physics · Physics 2024-10-22 Nhat A. Nghiem

A quantum expansion parameter, analogous to the Hubble parameter in cosmology, is defined for a free particle quantum wavefunction. By considering the universe as an initial single Gaussian quantum wavepacket whose mass is that of…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-28 A. D. Ernest

The Heisenberg picture of the minisuperspace model is considered. The suggested quantization scheme interprets all the observables including the Universe scale factor as the (quasi)Heisenberg operators. The operators arise as a result of…

General Relativity and Quantum Cosmology · Physics 2011-11-09 S. L. Cherkas , V. L. Kalashnikov

This chapter focuses on the status of the implementation of the dynamics in the canonical version of Loop Quantum Gravity (LQG). Concretely this means to provide a mathematical meaning of the quantum Einstein equations, sometimes called…

General Relativity and Quantum Cosmology · Physics 2023-04-03 Thomas Thiemann , Kristina Giesel

Most approaches towards a quantum theory of gravitation indicate the existence of a minimal length scale of the order of the Planck length. Quantum mechanical models incorporating such an intrinsic length scale call for a deformation of…

General Relativity and Quantum Cosmology · Physics 2025-05-21 Won Sang Chung , Georg Junker , Hassan Hassanabadi