Mark Jackson : Superstring Cosmology: New Physics in the Sky
- Uploaded by root ( 139 Views )Striking advances in observational cosmology over the past two decades have ushered in a golden era in cosmology, where our focus has turned from what the universe is made of to why it has the form we observe. The leading theory capable of answering such a question, Superstring Theory, does not appear capable of being tested using conventional accelerator-based experiments, forcing us to be more creative in our goal to verify or dismiss it. Focusing on brane inflation as a string theory-inspired model of inflationary cosmology, I will review how the cosmic microwave background (CMB) will provide a deluge of high- precision data into otherwise inaccessible energy scales. These data include possible "Transplanckian" signatures in the power spectrum, indications of variable sound speed or extra dimensions in non- Gaussianity, or constraining the inflation model parameter space using polarization. I then describe how the production of cosmic (super)strings in brane inflation would provide an additional means to verify superstring theory, and which would yield much detailed information about the underlying theory parameters.
Emil Bjerrum-Bohr : Twistor space, Amplitudes and the No-triangle Hypothesis in Gravity
- Uploaded by root ( 148 Views )Chris Beem : Chiral symmetry algebras and superconformal theories in four and six dimensions
- Uploaded by root ( 155 Views )Josh Garretson : T-duality and Generalized Geometry
- Uploaded by root ( 146 Views )T-duality has long been well understood locally via the Buscher rules. Global T-duality in the presence of an arbitrary background is much more involved. It relates backgrounds of different topology and can be seen to map 'regular' or commutative geometries to noncommutative ones. I will give a brief overview of these attempts at studying T-duality and show how T-duality acts very naturally in the context of Hitchin's generalized geometry. I will show that T-duality is an automorphism of the Courant bracket in the most general sense and give an example. If time permits, I will discuss applications to Poisson-Lie T-duality.
Ilarion Melnikov : Half-twisted correlators from the Coulomb branch
- Uploaded by root ( 178 Views )Ilarion Melnikov : N=2 heterotic flux vacua in the context of type II/heterotic duality
- Uploaded by root ( 147 Views )Robert Karp : A convex optimization problem in string theory
- Uploaded by root ( 144 Views )For nearly 25 years Calabi-Yau spaces have played a central role in string theory, yet no explicit metric was known. I will outline ideas pioneered by Donaldson and Yau that lead to such metrics numerically; then extend this approach to solving the hermitian Yang-Mills equation, and also obtain metrics on moduli spaces. Knowledge of these quantities is unavoidable for physical predictions.