Measuring Global Monopole Velocities, one by one

Abstract

We present an estimation of the average velocity of a network of global monopoles in a cosmological setting using large numerical simulations. In order to obtain the value of the velocity, we improve some already known methods, and present a new one. This new method estimates individual global monopole velocities in a network, by means of detecting each monopole position in the lattice and following the path described by each one of them. Using our new estimate we can settle an open question previously posed in the literature: velocity-dependent one-scale (VOS) models for global monopoles predict two branches of scaling solutions, one with monopoles moving at subluminal speeds and one with monopoles moving at luminal speeds. Previous attempts to estimate monopole velocities had large uncertainties and were not able to settle that question. Our simulations find no evidence of a luminal branch. We also estimate the values of the parameters of the VOS model. With our new method we can also study the microphysics of the complicated dynamics of individual monopoles. Finally we use our large simulation volume to compare the results from the different estimator methods, as well as to asses the validity of the numerical approximations made.

v2: Minor changes. Matches published version. 22 pages, 4 figures. v3: Erratum added that corrects a mistake in a formula and the corresponding tables, without modifying the conclussions

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Cited by in corpus (11)

• Scaling from gauge and scalar radiation in Abelian Higgs string networks
• Magnetic monopoles revisited: Models and searches at colliders and in the Cosmos
• Cosmic Microwave Background constraints for global strings and global monopoles
• Irreducible background of gravitational waves from a cosmic defect network: update and comparison of numerical techniques
• Extending and Calibrating the Velocity dependent One-Scale model for Cosmic Strings with One Thousand Field Theory Simulations
• Matter Lagrangian of particles and fluids
• Abelian-Higgs Cosmic String Evolution with CUDA
• General purpose graphics-processing-unit implementation of cosmological domain wall network evolution
• Evolution of Semilocal String Networks: II. Velocity estimators
• Revisiting the VOS model for monopoles
• Cosmological Evolution of Semilocal String Networks