Infrared bounds, reflection positivity and continuous symmetry breaking in classical and quantum spin systems
Lectures at the Prague Summer School on Mathematical Physics -- 1996
Prague, October 20-26, 1996
(Hand written lecture notes)
1. Classical Heisenberg models: the theorem of Fröhlich, Simon and Spencer.
2. Quantum Heisenberg models: intro; long range order parameter; quantum correlation inequalities (Bogoliubov, Falk-Bruch)
3. Quantum Heisenberg models continued: the theorem of Mermin and Wagner; the theorem of Dyson, Lieb and Simon (and its extensions)