A century of the Bose-Einstein condensation concept and half a century of the JINR experiments for observation of condensate in the superfluid 4He (He II)
Valentin Zagrebnov
Published: 2025/10/3
Abstract
This short review is devoted to celebration of two major events in quantum physics. The first one is the birth of the concept of Bose-Einstein condensation (1925) and the second is the experimental proof that it does exist and appears in the liquid 4He simultaneously with superfluidity below the $\lambda$-point (1975). The both of these events are tightly related to the Bogoliubov theory of superfluidity (1947). The existence of condensate in the system of interacting bosons is the key ansatz of this theory. Therefore, the experiments started in JINR in 1975 confirmed this prediction of the Bogoliubov theory that superfluidity of the liquid 4He (He II) should emerge at the same time as the Bose-Einstein condensation.