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Cluster Abundance Constraints for Cosmological Models with a Time-varying, Spatially Inhomogeneous Energy Component with Negative Pressure
The abundance of rich clusters is a strong constraint on the mass power spectrum. The current constraint can be expressed in the form ? -->8 ?${γ}m$ -->=0.5?0.1, where ?8 is the rms mass fluctuationExpand
Bond-orientational order in liquids and glasses
Bond-orientational order in molecular-dynamics simulations of supercooled liquids and in models of metallic glasses is studied. Quadratic and third-order invariants formed from bond sphericalExpand
The observational case for a low-density Universe with a non-zero cosmological constant
OBSERVATIONS are providing progressively tighter constraints on cosmological models advanced to explain the formation of large-scale structure in the Universe. These include recent determinations ofExpand
Cluster Abundance Constraints on Quintessence Models
The abundance of rich clusters is a strong constraint on the mass power spectrum. The current constraint can be expressed in the form $\sigma_8 \Omega_m^{\gamma} = 0.5 \pm 0.1$ where $\sigma_8$ isExpand
The Ekpyrotic universe: Colliding branes and the origin of the hot big bang
We propose a cosmological scenario in which the hot big bang universe is produced by the collision of a brane in the bulk space with a bounding orbifold plane, beginning from an otherwise cold,Expand
Cosmology - The cosmic triangle: Revealing the state of the universe
The cosmic triangle is introduced as a way of representing the past, present and future status of the universe. Our current location within the cosmic triangle is determined by the answers to threeExpand
Cosmology for Grand Unified Theories with Radiatively Induced Symmetry Breaking
The treatment of first-order phase transitions for standard grand unified theories is shown to break down for models with radiatively induced spontaneous symmetry breaking. It is argued that properExpand
Cosmic Concordance and Quintessence
We present a comprehensive study of the observational constraints on spatially flat cosmological models containing a mixture of matter and quintessence—a time-varying, spatially inhomogeneousExpand
From big crunch to big bang
We consider conditions under which a universe contracting towards a big crunch can make a transition to an expanding big bang universe. A promising example is 11-dimensional M-theory in which theExpand
Cosmological imprint of an energy component with general equation of state
We examine the possibility that a significant component of the energy density of the Universe has an equation of state different from that of matter, radiation, or cosmological constant ({Lambda} ).Expand