Peaks above the Harrison-Zel'dovich spectrum due to the Quark-Gluon to Hadron Transition

The quark-gluon to hadron transition affects the evolution of cosmological perturbations. If the phase transition is first order, the sound speed vanishes during the transition, and density perturbations fall freely. This distorts the primordial Harrison-Zel'dovich spectrum of density fluctuations below the Hubble scale at the transition. Peaks are produced, which grow at most linearly in wavenumber, both for the hadron-photon-lepton fluid and for cold dark matter. For cold dark matter which is kinetically decoupled well before the QCD transition clumps of masses below $10^{-10} M_\odot$ are produced.Comment: Extended version, including evolution of density perturbations for a bag model and for a lattice QCD fit (3 new figures). Spectrum for bag model (old figure) is available in astro-ph/9611186. 9 pages RevTeX, uses epsf.sty, 3 PS figure

Conserved Quasilocal Quantities and General Covariant Theories in Two Dimensions

General matterless--theories in 1+1 dimensions include dilaton gravity, Yang--Mills theory as well as non--Einsteinian gravity with dynamical torsion and higher power gravity, and even models of spherically symmetric d = 4 General Relativity. Their recent identification as special cases of 'Poisson--sigma--models' with simple general solution in an arbitrary gauge, allows a comprehensive discussion of the relation between the known absolutely conserved quantities in all those cases and Noether charges, resp. notions of quasilocal 'energy--momentum'. In contrast to Noether like quantities, quasilocal energy definitions require some sort of 'asymptotics' to allow an interpretation as a (gauge--independent) observable. Dilaton gravitation, although a little different in detail, shares this property with the other cases. We also present a simple generalization of the absolute conservation law for the case of interactions with matter of any type.Comment: 21 pages, LaTeX-fil

Cosmological inhomogeneities from the QCD transition

Schwarz D, Schmid C, Widerin P. Cosmological inhomogeneities from the QCD transition. 1997

Distortions of the Harrison-Zel'dovich spectrum from the QCD transition

Schwarz D, Schmid C, Widerin P. Distortions of the Harrison-Zel'dovich spectrum from the QCD transition. Presented at the Third International Conference on Physics and Astrophysics of the Quark Gluon Plasma, Jaipur, India

Deviations from the Harrison-Zel'dovich spectrum due to the Quark-Gluon to Hadron Transition

Schmid C, Schwarz D, Widerin P. Deviations from the Harrison-Zel'dovich spectrum due to the Quark-Gluon to Hadron Transition. HELVETICA PHYSICA ACTA. 1996;69(3):198-201.We investigate the effect of the quark-gluon to hadron transition on the evolution of cosmological perturbations. If the phase transitions is first order, the sound speed vanishes during the transition, and density perturbations fall freely. The primordial Harrison-Zel'dovich density fluctuations for scales below the Hubble radius at the transition develop peaks, which grow linearly with the wavenumber, both for the hadron-photon-lepton fluid and for cold dark matter. The large peaks in the spectrum produce cold dark matter clumps of 10(-8) to 10(-11) M.