The aim of this book is to present fundamental concepts in quantum mechanics and a general mathematical formalism beyond the wavefunction framework taught in introductory quantum mechanics courses. This includes topics such as Dirac formalism with bra- and ket-vectors in Hilbert space, Heisenberg formalism with matrices, approximation methods in quantum mechanics, scattering theory, atoms and electrons in magnetic fields, coherent states, field quantization and radiation theory, and the density matrix formalism. In addition to explaining the underlying theory in a detailed manner, we shall also provide a number of examples that will illustrate the formalisms "in action".

### About the author

J.L. holds since 2013 a position as Professor of Physics at the Norwegian University of Science and Technology. His research is focused on theoretical quantum condensed matter physics and he has received several prizes for his Ph.D work on the interplay between superconductivity and magnetism. He has also received the American Physical Society ”Outstanding Referee” award, selected among over 60.000 active referees. In teaching courses such as Classical Mechanics and Particle Physics for both undergraduate and graduate students, he has invariably received high scores from the students for his pedagogical qualities and lectures.