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We consider scalar tensor theories of gravity assuming that the scalar field is non minimally coupled with gravity. We use this theory to study evolution of a flat homogeneous and isotropic universe. In this case the dynamical equations can…

Astrophysics · Physics 2012-07-13 M. Demianski , E. Piedipalumbo , C. Rubano , C. Tortora

A kernel-based framework for spatio-temporal data analysis is introduced that applies in situations when the underlying system dynamics are governed by a dynamic equation. The key ingredient is a representer theorem that involves…

Statistics Theory · Mathematics 2020-11-16 Oleg Szehr , Dario Azzimonti , Laura Azzimonti

This paper reviews the dynamics of an isotropic and homogeneous cosmological scalar field. A general approach to the solution of the Einstein-Klein-Gordon equations is developed, which does not require slow-roll or other approximations.…

General Relativity and Quantum Cosmology · Physics 2025-04-15 J. W. van Holten

We study time-optimal protocols for controlling quantum systems which show several avoided level crossings in their energy spectrum. The structure of the spectrum allows us to generate a robust guess which is time-optimal at each crossing.…

Quantum Physics · Physics 2015-11-18 P. M. Poggi , F. C. Lombardo , D. A. Wisniacki

We apply stochastic quantization method to matrix models for the second quantization of loops in both discretized and continuum levels. The fictitious time evolution described by the Langevin equation is interpreted as the time evolution in…

High Energy Physics - Theory · Physics 2009-10-28 N. Nakazawa

The complex Langevin method is a leading candidate for solving the sign problem occurring in various physical situations, notably QCD at finite chemical potential. Its most vexing problem is `convergence to the wrong limit', where the…

High Energy Physics - Lattice · Physics 2011-10-27 Gert Aarts , Frank A. James , Erhard Seiler , Ion-Olimpiu Stamatescu

Solving the 4-d Einstein equations as evolution in time requires solving equations of two types: the four elliptic initial data (constraint) equations, followed by the six second order evolution equations. Analytically the constraint…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Matthew Anderson , Richard A. Matzner

We consider a cell-complex in an arbitrary Hausdorff space as a dynamical object that can be coupled to a field defined on the complex. The Langevin equation is then derived for this field. In other words, a noise-field is created resulting…

High Energy Physics - Theory · Physics 2007-05-23 F. Vanderseypen

Simulating time evolution of generic quantum many-body systems using classical numerical approaches has an exponentially growing cost either with evolution time or with the system size. In this work, we present a polynomially scaling hybrid…

Quantum Physics · Physics 2023-09-18 Nikita Astrakhantsev , Sheng-Hsuan Lin , Frank Pollmann , Adam Smith

This paper derives error bounds for regression in continuous time over subsets of certain types of Riemannian manifolds.The regression problem is typically driven by a nonlinear evolution law taking values on the manifold, and it is cast as…

Dynamical Systems · Mathematics 2022-09-09 Nathan Powell , Jia Guo , Sai Tej Parachuri , John Burns , Boone Estes , Andrew Kurdila

In this paper, we study the spontaneous scalarization of an extended, self-gravitating system which is static, cylindrically symmetric and possesses electromagnetic fields. We demonstrate that a real massive scalar field condenses on this…

General Relativity and Quantum Cosmology · Physics 2021-06-16 Yves Brihaye , Rogério Capobianco , Betti Hartmann

We adopt a covariant formalism to derive exact evolution equations for nonlinear perturbations, in a universe dominated by two scalar fields. These scalar fields are characterized by non-canonical kinetic terms and an arbitrary field space…

High Energy Physics - Theory · Physics 2009-01-23 Sebastien Renaux-Petel , Gianmassimo Tasinato

Probabilistic modeling of multidimensional spatiotemporal data is critical to many real-world applications. As real-world spatiotemporal data often exhibits complex dependencies that are nonstationary and nonseparable, developing effective…

Machine Learning · Statistics 2023-06-01 Mengying Lei , Aurelie Labbe , Lijun Sun

Recently a Hamiltonian formulation for the evolution of the universe dominated by multiple oscillatory scalar fields was developed by the present author and was applied to the investigation of the evolution of cosmological perturbations on…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Takashi Hamazaki

We derive exact general solutions (as opposed to attractor particular solutions) for the evolution of a scalar field $\phi$ in a universe dominated by a background fluid with equation of state parameter $w_B = -1$, extending earlier work on…

General Relativity and Quantum Cosmology · Physics 2026-01-26 Patrick Hu , Robert J. Scherrer

We develop a mathematically rigorous path integral representation of the time evolution operator for a model of (1+1) quantum gravity that incorporates factor ordering ambiguity. In obtaining a suitable integral kernel for the…

Mathematical Physics · Physics 2017-06-08 John Haga , Rachel Lash Maitra

We set up a real-time path integral to study the evolution of quantum systems driven in real-time completely by the coupling of the system to the environment. For specifically chosen interactions, this can be interpreted as measurements…

Quantum Physics · Physics 2015-11-04 Debasish Banerjee , Florian Hebenstreit , Fu-Jiun Jiang , Mark Kon , Uwe-Jens Wiese

The dynamical systems methods are used to study evolution of the polymerised scalar field cosmologies with the cosmological constant. We have found all evolutional paths admissible for all initial conditions on the two-dimensional phase…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Orest Hrycyna , Jakub Mielczarek , Marek Szydlowski

A stochastic field theory approach is applied to a coarse-grained polymer model that will enable studies of polymer behavior under non-equilibrium conditions. This article is focused on the validation of the new model in comparison to…

Soft Condensed Matter · Physics 2024-03-04 Shangren Zhu , Patrick T. Underhill

Numerical discretization of the large-scale Maxwell's equations leads to an ill-conditioned linear system that is challenging to solve. The key requirement for successive solutions of this linear system is to choose an efficient solver. In…

Numerical Analysis · Mathematics 2023-01-31 Sahar Borzooei , Victorita Dolean , Pierre-Henri Tournier , Claire Migliaccio