Black Holes for the Curious Physicist (and Mathematician)
Malcolm Perry (University of Cambridge)
September 30, 2003
I will describe the basic properties of black holes, the uniqueness theorems, and the laws of black hole mechanics. This allows to progress to a description of the Hawking effect and black hole evaporation. then, I will briefly review the information paradox. Finally, I will comment about some of the string theory results that shed some light on the problems of semiclassical black hole theory.
Quantum Gravity With a Positive Cosmological Constant
Lee Smolin (Perimeter Institute)
May 20, 2003
Recent results of loop quantum gravity which concern the case of positive cosmological constant will be presented. These include the existence of an exact quantum state which is both an exact solution to the quantum field theory constructed from quantizing general relativity and has a good low energy limit which recovers quantum field theory on de Sitter spacetime. Related results to be discussed include the extension of the thermal properties of quantum fields in deSitter spacetime to full quantum gravity with a positive cosmological constant and the recovery of the horizon entropy and N bound. Predictions can also be derived for new and potentially observable phenemona coming from planck scale corrections to dispersion relations and quantum gravity corrections to inflaton potentials. Final, issues of quantum theory in cosmological spacetimes and in the presence of horizons are discussed and new proposals to resolve them based on relational approaches to quantum cosmology are described. The work to be described was done by and in collaboration with Chopin Soo, Hideo Kodama, Fotini Markopoulou, Laurent Freidel, Carlo Rovelli and Stephon Alexander.
The Birth of Flight Control: Flight Testing with the Wright Brothers
Gareth D. Padfield (The University of Liverpool, UK)
James Bibby Professor of Aerospace Engineering
May 2, 2003
The Wright Brothers achieved their goal through their innovations in flight control and the title of this lecture reflects the notion that their breakthrough was to invent flight control in a style that would shape all future aircraft, and enable them to progress to the first powered flight in 1903. The Wright Brothers were the first aeronautical engineers and first test pilots and 1902 was perhaps the most critical year in their work and the development of the aeroplane. The story of their invention in this centenary year is told through a description and assessment of the technical challenges faced by the Wrights, their unique approach to innovation and their dedication to their goals. The story is enhanced through the understanding gained from the development and testing of high-fidelity simulations of the Wright aircraft on the Liverpool Flight Simulator. Activities from this project will feature in the lecture, including wind tunnel tests, multi-body dynamic modelling, closed-loop control analysis and test flying.
Laws of Nature in Physics and Philosophy
Jessica M Wilson (Univeristy of Michigan)
April 22, 2003
I argue that certain hypotheses of contemporary fundamental physics support one philosophical account of laws of nature over another.