String Cosmology (08rit128)


Cliff Burgess (McMaster University and Perimeter Institute)


The recent flood of precise cosmological observations have for the first time succeeded in precisely pinning down the properties of the observed early universe. This success has revealed two startling features of the universe, which has revolutionized our picture of nature in two distinct ways.

First, by allowing for the first time the measurement of the total energy content of the universe, these observations have revealed the
existence of *two* new, still not understood, forms of matter (Dark Matter and Dark Energy) which together make up 95% of what is out
there. Second, they provide the beginnings of hard evidence for the existence of a previously undetected very early 'inflationary' epoch
of the universe, during which its size increased in an accelerated way.

Both of these discoveries potentially change our picture of the laws of nature in a fundamental way, since both imply the existence of new
kinds of particles and interactions that have hitherto gone undetected in experiments on Earth. As a result they have caught the attention of those theorists who study our best-formulated theory of how nature works at its most fundamental level. The relatively new field of string cosmology aims to try to see if string theory (our best-motivated theory of nature at its most fundamental) can explain the Dark Matter and Dark Energy, and to see if it can account for why the universe might have undergone a very early epoch of inflationary expansion. Besides being interesting in its own right, success in either of these directions could provide the first real experimental tests of string theory, which has so far proven elusive.

The Banff International Research Station for Mathematical Innovation and Discovery (BIRS) is a collaborative Canada-US-Mexico venture that provides an environment for creative interaction as well as the exchange of ideas, knowledge, and methods within the Mathematical Sciences, with related disciplines and with industry. The research station is located at The Banff Centre in Alberta and is supported by Canada's Natural Science and Engineering Research Council (NSERC), the US National Science Foundation (NSF), Alberta's Advanced Education and Technology, and Mexico's Consejo Nacional de Ciencia y Tecnologí­a (CONACYT).