Superfluidity and closely related to it, superconductivity are very general phenomena that can occur on vastly different energy scales. Their underlying theoretical mechanism of spontaneous symmetry breaking is even more general and applies to a multitude of physical systems.

In these lecture notes, a pedagogical introduction to the field-theory approach to superfluidity is presented. The connection to more traditional approaches, often formulated in a different language, is carefully explained in order to provide a consistent picture that is useful for students and researchers in all fields of physics.

After introducing the basic concepts, such as the two-fluid model and the Goldstone mode, selected topics of current research are addressed, such as the BCS-BEC crossover and Cooper pairing with mismatched Fermi momenta.

Modern approach to the subject matter Based on course-tested lecture material Self-contained presentation suitable as textbook or as self-study guide Includes supplementary material: sn.pub/extras

Inhalt
Introduction.- Superfluid Helium.- Superfluidity in Quantum Field Theory.- Relativistic Two-Fluid Formalism.- Fermionic Superfluidity: Cooper Pairing.- Meissner Effect in a Superconductor.- BCS-BEC Crossover.- Low-Energy Exitations in a Fermionic Superfluid.- Cooper-Pairing with Mismatched Fermi Momenta.- References.