Frank C. Hoyt

Frank Clark Hoyt (12 September 1898 – 30 January 1980) was an American physicist, regarded as one of the first theoretical physicists to come from the USA in the period that quantum mechanics was being developed.

Biography He was born to Carrie Louise Stokes and Louis Phelps Hoyt, an organist. He went to Harvard School for Boys. At school, his primary interest was literature - he wanted to study Greek - but the path to science developed in his final year after taking chemistry and physics courses. He enrolled at the Massachusetts Institute of Technology, starting in chemical engineering, moving towards pure chemistry before being influenced by his teachers towards physics. After completing his BSc in 1918 (a year early because of World War I), he remained as an assistant, taking his MSc a year later on the subject of X-ray crystallography. In 1920, he followed David L. Webster as a graduate student to Stanford University, working with Webster on excitation potentials of X-ray lines until 1921, when he completed his PhD.

Theoretical physics After a period as an instructor at the University of Wisconsin - his transition period to becoming a theoretician - he was successful in an application for a National Research Council (NRC) fellowship to travel to Europe for studies. Danish physicist, Niels Bohr, had founded the Institute for Theoretical Physics at the University of Copenhagen which became the World centre of quantum-physics studies. Hoyt travelled around Europe with his parents before basing himself in Copenhagen from autumn 1922 to spring 1924. During this period, he met key personalities who developed quantum mechanics - and their classically-established elders - with whom he was to maintain connexions throughout his career, including Bohr, Albert Einstein, Erwin Schrödinger, Werner Heisenberg, Wolfgang Pauli, John von Neumann, Leo Szilard and Fritz London. While there, he learned to speak Danish, along with others such as Pauli, and stayed with a Danish family, although all of the conversations Hoyt had with Bohr were in English. Between 1923 and 1925, he wrote papers on the application of Bohr's correspondence principle and he translated Bohr's Nobel Prize lecture into English and also later ones. In 1924, he joined the University of Chicago, with the encouragement of Henry Gale (an avowed experimental physicist); this was initially under a second NRC fellowship, before employment as a research associate from 1926. On 16 January 1926, he married Elisabeth Louisa Camp and they had a daughter, Elisabeth, the same year. He was assistant professor at Chicago from 1927. Until 1927, Hoyt was the sole theoretical physicist in Chicago and his lectures were attended by Karl and Arthur Compton. Karl Compton wrote a reference supporting Hoyt's application for funds to study in Berlin: "There is no field in physics at the present time which is of such great importance and in which there is more to be done than in the field which Dr. Hoyt has chosen." He received a Guggenheim Fellowship for a year from September 1927, nominally with Schrödinger, who was at the University of Zurich, although he spent a good deal of this time in Berlin.