Classical physics In contrast to classical physics, "modern physics" is a slightly looser term which may refer to just quantum physics or to 20th and 21st century physics in general. Modern physics includes quantum theory and relativity, when applicable. A physical system can be described by classical physics when it satisfies conditions such that the laws of classical physics are approximately valid. In practice, physical objects ranging from those larger than atoms and molecules, to objects in the macroscopic and astronomical realm, can be well-described (understood) with classical mechanics. Beginning at the atomic level and lower, the laws of classical physics break
Ugo Fano Fano spent 1936–37 with Werner Heisenberg in Leipzig. In 1939, he married Camilla Lattes, also known as "Lilla", a teacher who would collaborate with him in a well-known book on atomic and molecular physics, "Physics of Atoms and Molecules" (1959). Appendix III of this book presents an elementary description of the collision of two charged particles, which was used by Richard Feynman in lectures that have been published as "". An expanded version of this book was subsequently published as "Basic Physics of Atoms and Molecules" (1972). Later that year, he immigrated to the United States due to increasing antisemitic