2 Landau's theory cannot describe all the continuous phase transition such as the transitions between quantum ordered phase Orders Symmetry brea king orders Nonsymmetry breaking orders ° Particle" condensation Symmetry goup Nambu-Gokstone mode Quantum system Classical system Quantum orders Gapped Topobgical orders Fermi liquids String-net condensation Topobgical field theory Fermi surface topology COnformal algebra, ??>) Projective sym metry group Gapless Gauge bosons/Fermions. Exotic superconductor, Lifshiz phase transition Spin liquid, FQHE Spin liquidLandau's theory cannot describe all the continuous phase transition such as the transitions between quantum ordered phase Spin liquid Lifshiz phase transition Exotic superconductor, Spin liquid, FQHE