Skip to main content

Cosmic Strings and Large-Scale Structure

Cosmic Strings and Large-Scale Structure

The motivation
One of the outstanding problems in cosmology today is developing a more precise understanding of structure formation in the universe, that is, the origin of galaxies and other large-scale structures. Existing theories for the structure formation of the Universe fall into two categories, based either upon the amplification of quantum fluctuations in a scalar field duringinflation, or upon a symmetry breaking phase transition in the early Universe which leads to the formation of topological defects. While techniques for computing density perturbations for the former are well established, only little quantitative work exists for the latter due to calculational difficulties in modelling  nonlinear effects, especially for cosmic string models.
We know that topological defects are an inevitable consequence of unification theory during the symmetry breaking. Among other defects, cosmic strings have been proved to be the most potential one for cosmic structure formation. The cosmic string scenario predated inflation as a realistic structure formation model, but it has proved computationally much more challenging to make robust predictions with which to confront observations. Only until recently, significant progress in understanding cosmic strings as seeds for large-scale structure and Cosmic Microwave Background (CMB) anisotropies has been achieved.
The mechanism
Cosmic strings appear in the form of carrying energy, resulting from the symmetry breaking phase transition in the early universe. Through gravitaional interactions, they serve as seed of structure formation attracting their neighbouring matter. In terms of relativity (see the picture below), we can see the geodesic path of light curved towards a string when light passing by it. When strings evolve scaling from smaller scales to larger ones, they seed perturbations into the matter energy density of the universe.

Conical spacetime around a cosmic string.
Simulations
To investigate the structure formation by cosmic strings, we first perform high-resolution simulations to obtain the evolution history of cosmic strings:
A network of cosmic strings obtained from a high-resolution simulation. A snapshot of cosmic string network in a high-resolution simulation.

We then use this set of string networks to serve as the gravitational source seeding perturbations into the matter energy density of the universe:
  • Structure formation (CDM) by cosmic strings (movie):
    the distribution of matter energy density of the universe
    (box size: 128 Mpc/h; 2D projection)
  • Structure formation (CDM vs. HDM) by cosmic strings
    the distribution of matter energy density of the universe
    (box size: 128 Mpc/h; 2D projection)
  • Gaussian vs non-Gaussian
    the distribution of matter energy density of the universe
    (box size: 120 Mpc/h; isodensity surface)

  
 
Cosmic microwave anisotropies induced by cosmic strings (ACSSV).

Popular posts from this blog

Hidden Wiki

Welcome to The Hidden WikiNew hidden wiki url 2015 http://zqktlwi4fecvo6ri.onion Add it to bookmarks and spread it!!!
Editor's picks Bored? Pick a random page from the article index and replace one of these slots with it.
The Matrix - Very nice to read. How to Exit the Matrix - Learn how to Protect yourself and your rights, online and off. Verifying PGP signatures - A short and simple how-to guide. In Praise Of Hawala - Anonymous informal value transfer system. Volunteer Here are five different things that you can help us out with.
Plunder other hidden service lists for links and place them here! File the SnapBBSIndex links wherever they go. Set external links to HTTPS where available, good certificate, and same content. Care to start recording onionland's history? Check out Onionland's Museum Perform Dead Services Duties. Introduction PointsAhmia.fi - Clearnet search engine for Tor Hidden Services (allows you to add new sites to its database). DuckDuckGo - A Hidden S…

[SOLVED] IDM WAS REGISTERED WITH A FAKE SERIAL NUMBER

[SOLVED] IDM WAS REGISTERED WITH A FAKE SERIAL NUMBER
Good News [May 08, 2015]: IDM developers got smarter, but the crackers are always a step ahead. Follow this article and send an email to uglyduckblog@gmail.com if you are desperate. I can NOT post any crack here for legal reasons. Happy Downloading with IDM. ;) *********** first tip is to use latest crack for idm from  onhax.net idm universal web crack and make sure u are using all latest vers I am sure many of us are too much dependent on Internet Download Manager a.k.a. IDM. The main reason didn’t permanently switch to linux was IDM. I mainly use it for batch downloading and download streaming videos. Till yesterday, IDM was working fine with me (of course with fake serial numbers, keygen, crack, patch etc. which could be found with little effort). But few days ago, with the latest update version 6.18 build 7 (released on Nov 09, 2013) Internet Download Manager was literally had a breakthrough and crushed all the serial numbers, …

camtasia 9 key

1.abul hossain Key : BBCUV-UVDRC-M8C5S-CHMX7-2M3A5 2.YR-Invasion Key=BBCUVUVDRCM8C5SCHMX72M3A5