The Parameters of Cosmic Structure Formation

J. Richard Bond

Canadian Institute for Theoretical Astrophysics, University of Toronto

We probe the interconnected "cosmic web" of structure in the Universe over a wide range of wavebands with cosmic microwave background (CMB) experiments, galaxy and cluster redshift surveys of large scale structure (LSS), and high redshift observations of forming galaxies and the intergalactic medium. The inflation-based cosmic structure formation paradigm we have been operating with for two decades has never been in better shape: combining all of the current CMB+LSS data, especially from the headline-generating Boomerang and Maxima CMB experiments, points to the remarkable conclusion that the initial fluctuations were nearly scale invariant and the local Hubble patch we can access has little mean curvature, both predictions of (non-baroque) inflation theory. Even stranger is the evidence from CMB and LSS observations that the density of the universe is dominated by unclustered energy akin to the cosmological constant, at the same level as that inferred from high redshift supernova observations.

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The case for dark matter in cosmology

Ue-Li Pen

Canadian Institute for Theoretical Astrophysics, University of Toronto

I review the observational and theoretical evidence for non-baryonic cold dark matter in the universe. The direct evidence comes from a combination of the cosmic microwave background, clusters of galaxies and galaxy rotation curves. By adding this extra component of cold dark matter, one can predict the power spectrum of matter, which has been tested on many different scales, and appears consistent with the cold dark matter scenario.

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The accelerating Universe: theory and observations

Eanna E. Flanagan

Cornell University

We review the theoretical naturalness problem associated with the observed smallness of the cosmological constant. We discuss recent observational evidence (cosmic microwave background and type IA supernovae) that the dominant source of gravity on large scales in the Universe today is a component whose equation of state is close to that of a cosmological constant. We survey various theoretical scenarios that can explain the observations.

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An Introduction to String Theory

Cyrus Taylor

Case Western Reserve University

String theory is the most promising candidate for a Theory of Everything, and has dramatically expanded the framework within which theorists seek to explain the physical world. I will attempt to provide some insight into why string theory is such a seductive enterprise, as well as a quick review of the basic framework as presently understood.

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Large Extra Dimensions : Concepts, Constraints and New Directions

Mark Trodden

Syracuse University

In the last few years there has been a great deal of interest in the idea that the universe may consist of more dimensions than those we observe. This renewed interest stems from the possibility that gravity and particle physics may behave very differently from each other in such a space. I will review the motivations, basic ideas, and laboratory, astrophysical and cosmological constraints on such theories. I will then briefly describe some possible new directions based on exotic topologies for the extra-dimensional space.

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Gravity in Infinite Volume Extra Dimensions

Gia Dvali

New York University

We review the framework, in which our world is a 3-brane floating in a flat, infinite-volume extra space. The brane fluctuations induce a four-dimensional Einstein term, which generates an effectively 4D gravity on the brane. These theories exhibit the phenomenon of an "infrared transparency", due to which the long wavelength modes penetrate easier in extra dimensions. This phenomenon results in long distance astrophysical effects. For instance, the long wavelength cosmic radiation from distant sources can dissipate into extra dimensions at an in-principle-observable rate. The framework also allows the supersymmetry to be unbroken in the extra space, while broken on the brane, which may shed a new light on cosmological constant problem.

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Strings and Black Holes

David Lowe

Brown University

One of the most important developments in string theory has been the identification of the black hole microstates responsible for the Bekenstein-Hawking entropy. We will review the classic D-brane state counting calculations for charged black holes, and describe recent attempts to use the matrix model formulation of M-theory to obtain a more complete understanding of black hole entropy.

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First results from the relativistic heavy ion collider program

Steve Manly

University of Rochester

This summer the Relativistic Heavy Ion Collider (RHIC) at BNL began operation with a very succesful run colliding Au nuclei at energies of 60 and 130 GeV/nucleon pair. The motivation and methodology of relativistic heavy ion physics will be discussed and the first trickle of results from RHIC will be reviewed.

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