Como Conference

The conference was part of the Volta centennial anniversary celebrations () ordered by the government of Benito Mussolini. The physics conference was organized by the Italian Physical Society. The program was organized by Quirino Majorana, president of the society. He was joined by Hendrik Lorentz, Aimé Cotton, Robert Andrews Millikan, Max von Laue and Giancarlo Vallauri as vicepresidents of the congress. The first four days were dedicated to works related to Volta, and the rest of the time was reserved for the topic of matter and radiation. in his residence at Villa Torlonia. == Topics ==

Bohr's complementarity On the 16th September, Niels Bohr presented a seminal lecture titled "The Quantum Postulate and the Recent Development of Atomic Theory" that introduced the principle of complementarity. The idea was motivated by a discussion in February–March with Werner Heisenberg, who had recently introduced the uncertainty principle. During the discussions, Heisenberg discussed the need to find the boundary between quantum evolution and macroscopic dynamics. This discussion represents the introduction of the hypothesis now known as the Heisenberg cut. Hendrik Lorentz praised Bohr's clarity of the presentation but regretted that there was not enough time for discussions. These results boosted Enrico Fermi's reputation outside Italy. He ruled it out using special relativity. By his calculation, the electron radius would have to be as large at least 10 femtometres to explain its magnetic moment, much larger than expected by experiments. Lorentz wrote about it after being contacted by Paul Ehrenfest, after his assistants George Uhlenbeck and Samuel Goudsmit had postulated the electron spin degree of freedom to explain atomic spectra. This work was Lorentz's last publication. == Participants ==

The list of physicists that attended included nine of Nobel Prize laureates in Physics, two Nobel Prize laureates in Chemistry, and various founders of quantum mechanics. In in his biography, Emilio Segrè says that he and Franco Rasetti were not invited but entered the lectures anyway. ==See also==