The invisible universe: Dark matter and dark energy. Review talks given in the 3rd Aegean school, Karfas, Chios Island, Greece from 26th of September to 1st of October 2005.
This book is an edited version of the review talks given in the Third Aegean School on the Invisible Universe: Dark Matter and Dark Energy, held in Karfas on Chios Island, Greece, from 26th of September to 1st of October 2005. The aim of the book is to present an advanced multiauthored textbook which meets the needs of both the postgraduate students and the young researchers, in the field of modern cosmology and astrophysics. The issue of dark matter and dark energy is one of the central interests in astroparticle physics, astrophysics, astronomy, and modern cosmology. Much of observational data indicate that there is a missing matter and missing energy in the universe. Evidence of the existence of this unknown form of matter and energy can be obtained from different sources. In astrophysics, the dynamics of galaxy formation and galaxy clusters can give information on the amount of missing matter. In astroparrticle physics, particle candidates were proposed from string theory and supersymmetry to identify the unknown matter. In cosmology, the recent data from cosmic microwave background and supernovae observations strongly indicate that there is a large amount of an unknown form of energy in the energy balance of the universe. The purpose of this book is to present these issues and to discuss in detail the physics involved. The first part of the book presents the problem of missing matter of the universe as seen by astroparticle physics and astrophysics. G. Lazaride reviews the main proposals of particle physics for the composition of the dark matter. Candidate constituents are neutralinos, axinos, and gravitinos. A model is presented which possesses a wide range of parameters consitent with the data on dark matter abundance as well as other phenomenological constraints. In view that many particle theories will be tested in the next round experiments in large accelerators, e.g. in the Large Hadron Accelerator, a more phenomenological approach to dark matter in elementary particle physics is adopted in the chapter by A. Lahanas. Here it is shown that the dark matter problem possibly has a supersymmetric origin. Next, J. Vergados, after reviewing supersymmetric models with their parameters constrained from the recent data at low energies and cosmological observations, is suggesting experiments of direct detection of dark matter mainly through a neutralino-nucleus interaction. J. Silks chapter describes the confrontation of structure formation with observation, and it focuses on the detection of the most elusive component, the non-baryonic dark matter. It explaines how galaxy formation theory is driven by phenomenology and by numerical simulations of dark matter clustering and gravity. Once the complications of star formation are incorporated, the theory becomes very complex. Semi-analytical perspectives of the theory are presented that may shed some insight into the nature of galaxy formation. The second part of the book deals with the energy balance of the universe. P. Tozzi presents the basic procedures to constrain the cosmological parameters which describe the energy content of the universe. Data from clusters of galaxies and their X-ray properties are used as cosmological tools to deduce information on these parameters. The difficulties in analysing recent galaxy redshift surveys data are explained by W. Percival. A very interesting example is provided of joint analysis of the latest cosmic microwave background and large-scale structure data, leading to a set of cosmological parameter constraints. R. Crittenden discusses the evidence for dark energy coming from a wide variety of data. After reviewing the physics of the cosmic microwave background, it discusses the different methods that are used in determining the dark energy's density, evolution and clustering properties and the crucial role the microwave background plays in all of these methods. L. Perivolaropoulos's chapter deals with another interesting manifestation of the presence of dark energy in the universe: the late time acceleration. It is a consequence of the recent observational data obtained from type Ia supernova surveys that support the accelerating expansion of the universe. The methods of the analysis of the data are reviewed and the theoretical implications obtained from their analysis are discussed. M. Sami presents current theoretical models for dark energy. These models rely on scalar field dynamics. M. Sami focusses mainly on the underlying basic feaures raher than on concrete scalar field models. The cosmological dynamics of standard scalar fields, phantoms, and tachyon fields is developed in detail. Scaling solutions are discussed emphasizing their importance in modelling dark energy. The developed concepts are implemented in an example of quintessential inflation. The third part of the book discusses the issue of dark matter and dark energy beyond the standard theory of general relativity. Higher dimensional string and brane theories are employed, and also theories that modify the usual Newtonian dynamics. An introduction to high-dimensional theories is given by I. Antoniadis. The basic idea is that the apparent weakness of gravity can be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our universe must be confined. The main properties of this scenario are reviewed and its implications for observations at both particle colliders and in non-accelerator gravity experiments are discussed. These ideas are applied to cosmology in R. Maartens' chapter. As explained by L. Perivolaropoulos, an accelerating universe requires the presence of a dark energy field with effectively negative pressure. An alternative to dark energy is that gravity itself may behave differently from general relativity on the largest scales, in such a way as to produce acceleration. In this chapter an example of modified gravity is presented which is provided by braneworld models that self-accelerate at late times. The challenges of dark matter and dark energy in the context of string theory are discussed in N. Mavromatos's article. The most successful alternative to dark matter in bound gravitational systems is the modified Newtonian dynamics (MOND), which is discussed by R. Sanders. He presents the various attempts to formulate MOND as a modification of general relativity and he explains the covariant theories that have been proposed as a basis for this idea. Finally, local modifications of general relativity by making the Lagrangian an arbitrary function of the Ricci scalar are presented in R. Woodard's contribution. The interest of such theories is that they can reproduce the current phase of cosmic acceleration without dark energy. (Shortened preface of the work)
late time accelerating expansion of the universe
scientific article; zbMATH DE number 5519173