 Bogoliubov transformation

The Bogoliubov transformation is a mathematical technique frequently used in condensed matter physics and quantum field theory, primarily to describe systems of interacting particles, such as bosons or fermions. It is especially useful in the context of many-body quantum systems, where it helps in treating interactions and in studying phenomena like Bose-Einstein condensation and superfluidity. The essence of a Bogoliubov transformation lies in how it mixes the creation and annihilation operators of particles.