Explore the fascinating world of quantum gases in this 47-minute lecture by Jan Philip Solovej, presented by the International Mathematical Union. Delve into the thermodynamic limit, rigorous results, and experimental verification of quantum gas theories. Examine the groundbreaking Bogolubov approximation from 1947, including the diagonalization of Bogolubov Hamiltonians. Trace the development from Bogolubov's theory to the LHY (Lee-Huang-Yang) correction, and understand the rigorous mathematical arguments supporting these concepts. Gain valuable insights into the ground state of quantum gases and their significance in modern physics.