Stabilizing Moduli with String Cosmology

In this talk I will discuss the role of finite temperature quantum corrections in string cosmology and show that they can lead to a stabilization mechanism for the volume moduli. I will show that from the higher dimensional perspective this results from the effect of states of enhanced symmetry on the one-loop free energy. These states lead not only to stabilization, but also suggest an alternative model for cold dark matter. At late times, when the low energy effective field theory gives the appropriate description of the dynamics, the moduli will begin to slow-roll and stabilization will generically fail. However, stabilization can be recovered by considering cosmological particle production near the points of enhanced symmetry leading to the process known as moduli trapping.Comment: Talk presented at PASCOS 2004. To be published in proceedings (World Scientific, 2004

Reevaluating the Cosmological Origin of Dark Matter

The origin of dark matter as a thermal relic offers a compelling way in which the early universe was initially populated by dark matter. Alternative explanations typically appear exotic compared to the simplicity of thermal production. However, recent observations and progress from theory suggest that it may be necessary to be more critical. This is important because ongoing searches probing the microscopic properties of dark matter typically rely on the assumption of dark matter as a single, unique, thermal relic. On general grounds I will argue that non-thermal production of dark matter seems to be a robust prediction of physics beyond the standard model. However, if such models are to lead to realistic phenomenology, they must sit in a restrictive theoretical framework. As we will show, as a consequence of such restrictions, viable models will result in concrete and testable predictions. Although many challenges remain, the non-thermal component of such models may offer a new way to test string theories that are formulated to provide realistic particle physics near the electroweak scale.Comment: 22 pages, no figure

Children and international relations : a new site of knowledge?

Recent years have seen the growth of approaches critical of traditional state-centred examinations of international relations, arguing instead for analyses that recognise actors and methods previously held largely silent within the mainstream International Relations (IR) discourse. This article argues that children are a group of actors worthy of similar recognition. Despite the fact that 'childhood studies' are comparatively well established in a number of academic disciplines, similar recognition has been later in coming to the study of IR. This article aims to address this perceived gap in the literature by first of all outlining the ways in which the discourse surrounding the child in IR has so far developed. This leads into an, examination of how the child may potentially best be conceptualised within the mainstream discourse and the implications of the inclusion of children as a 'site of knowledge' through which the international system may be more clearly understood.Publisher PDFPeer reviewe

Is More Better? The Impact of Postsecondary Education on the Economic and Social Well-Being of American Society

Provides a review of research literature that examines the impact of higher education on individuals and society. Looks at economic and non-economic benefits and costs associated with an increase in public investment in postsecondary education

Dilaton Dynamics from Production of Tensionless Membranes

In this paper we consider classical and quantum corrections to cosmological solutions of 11D SUGRA coming from dynamics of membrane states. We first consider the supermembrane spectrum following the approach of Russo and Tseytlin for consistent quantization. We calculate the production rate of BPS membrane bound states in a cosmological background and find that such effects are generically suppressed by the Planck scale, as expected. However, for a modified brane spectrum possessing enhanced symmetry, production can be finite and significant. We stress that this effect could not be anticipated given only a knowledge of the low-energy effective theory. Once on-shell, inclusion of these states leads to an attractive force pulling the dilaton towards a fixed point of S-duality, namely $g_s=1$. Although the SUGRA description breaks down in this regime, inclusion of the enhanced states suggests that the center of M-theory moduli space is a dynamical attractor. Morever, our results seem to suggest that string dynamics does indeed favor a vacuum near fixed points of duality.Comment: 39 pages, 7 figures, minor corrections and reference adde