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We study the formation and evolution of an interconnected string network in large-scale field-theory numerical simulations, both in flat spacetime and in expanding universe. The network consists of gauge U(1) strings of two different kinds…

High Energy Physics - Theory · Physics 2008-11-26 Jon Urrestilla , Alexander Vilenkin

Previously developed analytic models for the evolution of cosmic string and monopole networks are applied to networks of monopoles attached to two or more strings; the former case is usually known as cosmic necklaces. These networks are a…

High Energy Physics - Phenomenology · Physics 2014-11-21 C. J. A. P. Martins

We investigate the evolution of infinite strings as a part of a complete cosmic string network in flat space. We perform a simulation of the network which uses functional forms for the string position and thus is exact to the limits of…

General Relativity and Quantum Cosmology · Physics 2013-05-29 Vitaly Vanchurin , Ken Olum , Alexander Vilenkin

The equations describing a two-component cosmological fluid with linearized density perturbations are investigated in the small wavelength or large $k$ limit. The equations are formulated to include a baryonic component, as well as either a…

Astrophysics · Physics 2009-11-11 R. M. Gailis , N. E. Frankel

The unprecedented amount and the excellent quality of lensing data that the upcoming ground- and space-based surveys will produce represent a great opportunity to shed light on the questions that still remain unanswered concerning our…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-27 Carolina Parroni , Edouard Tollet , Vincenzo F. Cardone , Roberto Maoli , Roberto Scaramella

Feature propagation in Deep Neural Networks (DNNs) can be associated to nonlinear discrete dynamical systems. The novelty, in this paper, lies in letting the discretization parameter (time step-size) vary from layer to layer, which needs to…

Optimization and Control · Mathematics 2022-04-20 Harbir Antil , Hugo Díaz , Evelyn Herberg

We establish a method to trace the Lagrangian evolution of extended objects consisting of a multicomponent scalar field in terms of a numerical calculation of field equations in three dimensional Eulerian meshes. We apply our method to the…

High Energy Physics - Phenomenology · Physics 2009-11-07 Masahide Yamaguchi , Jun'ichi Yokoyama

There are many surprising and perhaps counter-intuitive properties of optimization of deep neural networks. We propose and experimentally verify a unified phenomenological model of the loss landscape that incorporates many of them. High…

Machine Learning · Computer Science 2019-06-12 Stanislav Fort , Stanislaw Jastrzebski

We investigate the linear growth rate of cosmological matter density perturbations of a viable f(R) model both numerically and analytically. We find that the growth rate in the scalar-tensor regime can be characterized by a simple analytic…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Tatsuya Narikawa , Kazuhiro Yamamoto

We compute the power spectra in the cosmic microwave background and cold dark matter (CDM) fluctuations seeded by strings, using the largest string simulations performed so far to evaluate the two-point functions of their stress energy…

Astrophysics · Physics 2009-10-30 Carlo Contaldi , Mark Hindmarsh , Joao Magueijo

Cosmic strings are generically predicted in many extensions of the Standard Model of particle physics. We propose a new avenue for detecting cosmic strings through their effect on the filamentary structure in the cosmic web. Using…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-11 M. A. Fernandez , Simeon Bird , Yanou Cui

The search for cosmic strings has been of renewed interest with the advent of precision cosmology. In this note we give a quantitative description of the nonlinear matter density fluctuations that can form from a scaling network of cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-06 Francis Duplessis , Robert Brandenberger

We describe the formalism of a quantitative analytic model for the evolution of realistic wiggly (as opposed to Goto-Nambu) cosmic strings. The model is particularly suited for describing the evolution of small-scale structure on string…

High Energy Physics - Phenomenology · Physics 2015-06-19 C. J. A. P. Martins , E. P. S. Shellard , J. P. P. Vieira

We present a model with an infinite volume bulk in which a braneworld with a cosmological constant evolves to a static, 4-dimensional Minkowski spacetime. This evolution occurs for a generic class of initial conditions with positive energy…

High Energy Physics - Theory · Physics 2009-10-07 Cedric Deffayet , Gia Dvali , Gregory Gabadadze , Arthur Lue

Training large and highly accurate deep learning (DL) models is computationally costly. This cost is in great part due to the excessive number of trained parameters, which are well-known to be redundant and compressible for the execution…

Machine Learning · Computer Science 2019-04-11 Mojan Javaheripi , Bita Darvish Rouhani , Farinaz Koushanfar

In this work, we consider the possibility that the dynamical dark energy hinted at by recent DESI data may be mimicked by the effects of additional components in the universe, potentially arising from topological defects. We find that the…

High Energy Physics - Phenomenology · Physics 2025-06-13 Haipeng An , Chengcheng Han , Borui Zhang

The Minkowski functionals are a mathematical tool to quantify morphological features of patterns. Some applications to the matter distribution in galaxy catalogues and N-body simulations are reviewed, with an emphasis on the effects of…

Astrophysics · Physics 2007-05-23 Alvaro Dominguez

An algorithm is proposed for the segmentation of image into multiple levels using mean and standard deviation in the wavelet domain. The procedure provides for variable size segmentation with bigger block size around the mean, and having…

We introduce a new phenomenological one-scale model for the evolution of domain wall networks, and test it against high-resolution field theory numerical simulations. We argue that previous numerical estimates of wall velocities are…

High Energy Physics - Phenomenology · Physics 2009-11-11 P. P. Avelino , C. J. A. P. Martins , J. C. R. E. Oliveira

Recently, a framework for analyzing time series by constructing an associated complex network has attracted significant research interest. One of the advantages of the complex network method for studying time series is that complex network…

Chaotic Dynamics · Physics 2015-06-04 Ruoxi Xiang , Jie Zhang , Xiao-ke Xu , Michael Small