**Contribution of domain wall networks to the CMB power spectrum**

*A. Lazanu, C. J. A. P. Martins, E. P. S. Shellard*

**Abstract**

We use three domain wall simulations from the radiation era to the late-time dark energy domination era based on the PRS algorithm to calculate the energy–momentum tensor components of domain wall networks in an expanding universe. Unequal time correlators in the radiation, matter and cosmological constant epochs are calculated using the scaling regime of each of the simulations. The CMB power spectrum of a network of domain walls is determined. The first ever quantitative constraint for the domain wall surface tension is obtained using a Markov chain Monte Carlo method; an energy scale of domain walls of 0.93 MeV, which is close but below the Zel'dovich bound, is determined.

**Keywords**

Domain walls, Topological defects, CMB, Phase transitions

**Physics Letters B**

Volume 747, Page 426

July 2015

**DOI:** 10.1016/j.physletb.2015.06.034**ADS Bibliographic code:** 2015PhLB..747..426L