Physics 18 Congresses 12 Quantum theory 5 Nuclear physics 4 Quantum field theory 4 Solids 4 Crystals 3 Defects 3 Electromagnetic theory 3 Matter 3 Molecular theory 3 Scattering (Physics) 3 Semiconductors 3 Spectrum analysis 3 Statistical mechanics 3 Collisions (Nuclear physics) 2 Constitution 2 Electricity 2 Electrons 2 Ions 2 Low temperatures 2 Magnetic properties 2 Many-body problem 2 Mathematical physics 2 Measurement 2 Molecular structure 2 Movement education 2 Order-disorder models 2 Particles (Nuclear physics) 2 Physical education and training 2