Large Parallel Cosmic String Simulation

Tufts University, Medford MA

Investigators

Abstract

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Cosmic strings connect fundamental theories of basic physics with observation of the universe on the largest scales. Cosmic strings are infinitesimally thin or even fundamental objects of cosmological length. They can arise from symmetry breaking in field theory or they can be the fundamental strings of string theory or 1-dimensional "D-branes". They can produce observational signatures in the cosmic microwave background, in cosmic rays, in ultra-high-energy neutrinos, or in gravity waves. If cosmic strings are detected, they will provide a window onto fundamental physics and energies beyond the reach of any accelerator. To interpret a cosmic string observation or to set limits on cosmic string properties from non-observation requires a quantitative understanding of the cosmic string network. In particular, since most cosmic string signatures arise from string loops, it is vital to know the density, sizes, and shapes of the loops whose effects might be detected. Because of the highly nonlinear nature of cosmic string processes, accurate understanding of the string network requires numerical simulation. This project will develop a new parallel simulation code, using algorithms adapted to parallel computing, and with more flexibility in generating initial conditions and analyzing the simulation data than previous codes. Parallel computing will provide for a simulation volume hundreds, perhaps a thousand times larger than has been simulated before, and an increase in the simulated time interval of up to factor of 10. This will allow much more time for initial condition artifacts to be damped out and for the string network to assume its final scaling form, from which the important network parameters can be extracted. The project will have a broader impact through the involvement of graduate undergraduate students and through opportunities for students from under-represented groups to participate in research. Its results will be broadly disseminated through publication in journals and made available to the public on the World Wide Web. It will benefit society by further connecting studies of the universe with studies of the fundamental laws of nature.