Quantum Field Theories, String Theory Quantum field theory 40 String models 40 Physics 38 Mathematical physics 19 Elementary Particles, Quantum Field Theory 18 Particles (Nuclear physics) 18 Mathematical Physics 15 Nuclear physics 6 Cosmology 5 Mathematical Applications in the Physical Sciences 5 Classical and Quantum Gravitation, Relativity Theory 4 Gravitation 4 Hadrons 4 Heavy ions 4 Mathematical Methods in Physics 4 Nuclear Physics, Heavy Ions, Hadrons 4 Condensed matter 3 Phase transformations (Statistical physics) 3 Algebra 2 Astrophysics 2 Astrophysics and Astroparticles 2 Condensed Matter Physics 2 Measurement 2 Measurement Science and Instrumentation 2 Particle Acceleration and Detection, Beam Physics 2 Particle acceleration 2 Particle and Nuclear Physics 2 Philosophy 2 Physical measurements 2