Generation of Fluctuations from the Quark-hadron Transition in the Early Universe


Book Description

We present a model for the generation of isothermal baryon density fluctuations in the early universe associated with the quark-hadron transition. The model is based on thermal nucleation theory for the creation of bubbles of the new phase and on entropy conservation during the phase transition. We find that the baryon number transport characteristics together with the rapid motion of the phase boundary can result in baryon density fluctuations with amplitudes considerably larger than the chemical equilibrium limit. All of these results depend on uncertain quantities associated with the underlying QCD physics. We discuss how uncertainties in these quantities translate into uncertainties in the fluctuation amplitude, shape, and mean separation.




The Quark-hadron Phase Transition in the Early Universe


Book Description

A first order phase transition between the quark-gluon plasma and the hadron gas can have important consequences for cosmology. These consequences result from the generation of isothermal baryon number density fluctuations as the universe passes through the phase transition. Calculations based upon simple models for the statistical mechanics of the two phases indicate that these fluctuations have large amplitude. The fluctuations persist after completion of the phase transition, being slowly damped by diffusion of baryon number. Upon decoupling of neutrons and protons at temperature T (approximately) 1 MeV, the neutrons begin to diffuse rapidly out of the dense regions and substantial segregation of the neutrons and protons results. Light element nucleosynthesis then occurs at T (approximately) 0.1 MeV. It is possible to reconcile the observed abundances of the light elements with model universes in which all of the matter is composed of baryons, the cosmological constant is zero, and the geometry is flat. 12 refs., 2 figs.




Density Fluctuations from the Quark-hadron Epoch and Primordial Nucleosynthesis


Book Description

We present a simple thermodynamic model of the quark-hadron transition in the early universe and use this model to estimate how the size of isothermal baryon number fluctuations which emerge from this epoch depend on the temperature of the transition and other uncertain quantities of the underlying QCD physics. We calculate primordial nucleosynthesis in the presence of these fluctuations and find that .cap omega. = 1 in baryons is possible only if the measured abundances of 7Li and 2H reflect substantial destruction during the evolution of the galaxy. 29 refs., 7 figs.




Energy Research Abstracts


Book Description

Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.







Generation of Cosmological Large-Scale Structure


Book Description

This volwne is the proceedings of the third school in particle astrophysics that Schramm and Galeotti have organized at Erice. The focus of thirs third school was the Generation of Cosmological Large-Scale Structure. It was held in November of 1996. The fIrst school in the series was on "Gauge Theory and the Early Universe" in May 1986, the second was on "Dark Matter in the Universe" in May 1988. All three schools have been successful under the auspices of the NATO Advanced Study Institute. This volume is thus the third in the series of the proceedings of these schools. The choice of the topic for this third school was natural, since the problem of generating a large-scale structure has become the most pressing problem in cosmology today. In particular, it is this generation of structure that is the interface between astronomical observations and particle models for the early universe. To date, all models for generating structures inevitably require new fundamental physics beyond the standard, SU x SU X U , model of high energy physics. The 3 2 I seeds for generating structures usually invoke unifIcation physics, and the matter needed to clump and form them seems to require particle properties that have not been seen in laboratories to date.










Dark Matter


Book Description




Primordial Nucleosynthesis and Evolution of Early Universe


Book Description

The International Conference "Primordial Nucleosynthesis and Evolution of Early Universe" was held in the presence of Prof. William Fowler on 4 - 8 September 1990 at the Sanjo Conference Hall, the University of Tokyo. This conference was co-sponsored by IUPAP, the International Union of Pure and Applied Physics, and by the University of Tokyo. The number of participants was 156, 58 from 15 foreign countries and 98 from Japan. About 120 contributions were submitted orally or as posters. Originally this conference was planned as a small gathering on Primordial Nucleosynthesis as indicated in the title, since primordial nucleosynthesis is the most important probe of the early stage of the universe. As is well known, light element abundances strongly depend on the time evolution of temperature and density. In this sense we can say that primordial nucleosynthesis is both the thermometer and speedometer of the early universe. Moreover, recently it has been claimed that primordial nucleosynthesis is an indicator of inhomogeneity of the early universe too. Now research of the primordial nucleosynthesis is in a boom. We, however, decided to include observational cosmology, of observations. taking into account the recent remarkable results Nowadays, to reveal the large scale structure of the universe and discover its origin is a main subject in cosmology. We invited distinguished scientists from all over the world, and very fortunately almost all these people accepted to attend this conference.