Go To Slide: 2001: A Spacetime Odyssey Quantum Mechanics / Spacetime Spacetime / Quantum Mechanics Two Laws Brief History I Brief History I (cont) Brief History II Brief History II (cont) Feynman paper Basic Ingredients Advantages Basic Ingredients Unitary Evolution Reduction Equivalence of Sum The Main Point Simple Examples Ideal Measurement Spacetime Alternatives Spacetime Alternatives II not every set There is none most generally Closed Systems most generally What's assumed Fine Grained Histories Coarse Grained Histories Measure of Interference Mechanisms of Decoherence Decoherence is Widespread Copenhagen Measured Variables Measured Variables Simple Examples Closed Timelike Curves Generalized QM 4-Geometries Non-Chronal Spacetimes Forward and Backward Simple Examples Key Idea Generalized QM No Equivalent States Recovered Hamiltonian QM He Was Right Main Point Again