John J. Hopfield

John Joseph Hopfield (born Jan Józef Chmielewski; July 8, 1891 – January 8, 1953) was a Polish-American physicist. Hopfield's published research included vacuum ultraviolet spectroscopy and solar ultraviolet spectroscopy. He was the discoverer of the "Hopfield bands" of oxygen and co-discoverer of the "Lyman–Birge–Hopfield bands" of nitrogen. For about a decade he was an industrial physicist working with technologies for fabricating glass windows, and was the inventor listed on several related patents.

Career Hopfield was born Jan Józef Chmielewski in 1891 in Płock, Poland and was orphaned at an early age. He grew up in an orphanage in Poland and briefly stayed with a Pennsylvania Dutch family in the United States before running away. Despite little formal education, he supported himself by teaching at a district school.

Hopfield's son, J. J. Hopfield, was born in 1933 and also became a noted physicist, receiving the 2024 Nobel Prize in Physics.

Select publications Ultraviolet Absorption and Emission Spectra of Carbon Monoxide The Ultra-Violet Band Spectrum of Nitrogen New Ultra-Violet Spectrum of Helium Absorption and Emission Spectra in the Region λ 600-1100. New Oxygen Spectra in the Ultraviolet and new Spectra in Nitrogen Preparation of Schumann plates The Ultraviolet Spectrum of the Sun from V-2 Rockets

Patents Line image producer Manufacture of multiple glass sheet glazing units Uniting of glass to glass and metals to glass Multiple glass sheet glazing unit and method of making the same Multiply glass sheet glazing unit Method of fabricating multiple glass sheet glazing units