Cosmic string induced sheetlike baryon inhomogeneities at the quark-hadron transition

Abstract

Cosmic strings moving through matter produce wakes where the density is higher than the background density. We investigate the effects of such wakes occurring at the time of a first order quark-hadron transition in the early universe and show that they can lead to a separation of the quark-gluon plasma phase in the wake region, while the region outside the wake converts to the hadronic phase. Moving interfaces then trap large baryon densities in sheetlike regions which can extend across the entire horizon. A typical separation between such sheets, at formation, is of the order of 1 km. Regions of baryon inhomogeneity of this nature, i.e., having a planar geometry and separated by such large distance scales, appear to be well suited for recent models of inhomogeneous nucleosynthesis to reconcile the large baryon to photon ratio implied by the recent measurements of the cosmic microwave background power spectrum.