4 giugno 1925

Satyendranath Bose sends to Albert Einstein a cover letter containing his article on a new derivation of Planck's Law, asking him if the article was worthy enough to be published in a German magazine (Zeitschrift fur Physik) and, if so, to help him in the translation of it from English into German: this is how the collaboration between the two physicists began, the one which would have led to the theoretical discovery of Bose-Einstein Condensate, a new state of matter that occurs at temperatures close to absolute zero.