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We propose an effectively nonperturbative approach to calculating scattering amplitudes in the perturbative regime. We do this in a discretized momentum space by using the QSE method to calculate all the contributions (to all orders in…

High Energy Physics - Phenomenology · Physics 2018-07-20 Neil Christensen , Joshua Henderson , Santiago Pinto , Cory Russ

In this paper, we present a novel derivative-free optimization framework for solving unconstrained stochastic optimization problems. Many problems in fields ranging from simulation optimization to reinforcement learning involve settings…

Optimization and Control · Mathematics 2024-04-19 Raghu Bollapragada , Cem Karamanli , Stefan M. Wild

We develop a non-linear framework for describing long-wavelength perturbations in multiple-field inflation. The basic variables describing inhomogeneities are defined in a non-perturbative manner, are invariant under changes of time slicing…

Astrophysics · Physics 2009-11-11 G. I. Rigopoulos , E. P. S. Shellard , B. J. W. van Tent

Stochastic reaction-diffusion models can be analytically studied on complex networks using the linear noise approximation. This is illustrated through the use of a specific stochastic model, which displays traveling waves in its…

Statistical Mechanics · Physics 2015-06-16 Malbor Asllani , Tommaso Biancalani , Duccio Fanelli , Alan J. McKane

We investigate the effect of time-dependent noise on the shape of a morphogen gradient in a developing embryo. Perturbation theory is used to calculate the deviations from deterministic behavior in a simple reaction-diffusion model of…

Tissues and Organs · Quantitative Biology 2007-05-23 Jeremy L. England , John Cardy

Accelerated gradient descent iterations are widely used in optimization. It is known that, in the continuous-time limit, these iterations converge to a second-order differential equation which we refer to as the accelerated gradient flow.…

Optimization and Control · Mathematics 2020-06-16 Mohammad Farazmand

A calculational approach in fluid turbulence is presented. Use is made of the attracting nature of the fluid-dynamic dynamical system. An approximate approach is offerred that effectively propagates the statistics in time. Loss of…

Fluid Dynamics · Physics 2007-05-23 Edsel A. Ammons

The unitary transformation of path-integral differential measure is described. The main properties of perturbation theory in the phase space of action-angle, energy-time variables are investigated. The measure in cylindrical coordinates is…

High Energy Physics - Theory · Physics 2007-05-23 J. Manjavidze

We study the impact of stochastic perturbations to deterministic dynamical systems using the formalism of the Ruelle response theory and explore how stochastic noise can be used to explore the properties of the underlying deterministic…

Statistical Mechanics · Physics 2015-05-27 Valerio Lucarini

The inclusion of stochastic terms in equations of motion for fluid problems enables a statistical representation of processes which are left unresolved by numerical computation. Here, we derive stochastic equations for the behaviour of…

Fluid Dynamics · Physics 2023-03-22 Oliver D. Street

After revealing difficulties of the standard time-dependent perturbation theory in quantum mechanics mainly from the viewpoint of practical calculation, we propose a new quasi-canonical perturbation theory. In the new theory, the dynamics…

Quantum Physics · Physics 2007-05-23 C. Y. Chen

The selective frequency damping method was applied to a bent flow. The method was used in an adaptive formulation. The most dangerous frequency was determined by solving an eigenvalue problem. It was found that one of the patterns,…

Fluid Dynamics · Physics 2020-11-06 Alexander V. Proskurin

This paper is the forth part of our series of work, is devoted to the analysis on the multiscales and cascade aspects of the statistical theory of isotropic turbulence based on the new Sedov-type solution. In this paper, we use the explicit…

Fluid Dynamics · Physics 2010-12-24 Zheng Ran

We provide a systematic formula, in terms of integer partitions, that generates perturbation theory explicitly at an arbitrary order. Our approach naturally includes an infinite number of perturbations and uses a single matrix equation that…

Strongly Correlated Electrons · Physics 2026-03-20 Joseph M. Jones , M. W. Long

Stochastic Structural Stability Theory (SSST) provides an autonomous, deterministic, nonlinear dynamical system for evolving the statistical mean state of a turbulent system. In this work SSST is applied to the problem of understanding the…

Fluid Dynamics · Physics 2014-12-30 Brian F. Farrell , Petros J. Ioannou

Stochastic HYPE is a novel process algebra that models stochastic, instantaneous and continuous behaviour. It develops the flow-based approach of the hybrid process algebra HYPE by replacing non-urgent events with events with…

Systems and Control · Computer Science 2014-11-18 Luca Bortolussi , Vashti Galpin , Jane Hillston

We give a concise, self-contained introduction to perturbation theory in cosmology at linear and second order, striking a balance between mathematical rigour and usability. In particular we discuss gauge issues and the active and passive…

Astrophysics · Physics 2009-06-23 Karim A. Malik , David R. Matravers

In the machine learning literature stochastic gradient descent has recently been widely discussed for its purported implicit regularization properties. Much of the theory, that attempts to clarify the role of noise in stochastic gradient…

Machine Learning · Computer Science 2022-10-21 Alberto Lanconelli , Christopher S. A. Lauria

We introduce a fundamental theory for the kinetics of systems of classical particles. The theory represents a unification of kinetic theory, Brownian motion and field theory. It is self-consistent and is the dynamic generalization of the…

Statistical Mechanics · Physics 2010-06-14 Gene F. Mazenko

We introduce a new variational characterization of Gaussian diffusion processes as minimum uncertainty states. We then define a variational method constrained by kinematics of diffusions and Schr\"{o}dinger dynamics to seek states of local…

High Energy Physics - Theory · Physics 2016-09-06 F. Illuminati , L. Viola