6th - 2nd Century BCE Kanada (philosopher) proposes that anu is an indestructible particle of matter, an "atom"; anu is an abstraction and not observable.[1]
430 BCE[2]Democritus speculates about fundamental indivisible particles—calls them "atoms"
1906 Charles Barkla discovers that each element has a characteristic X-ray and that the degree of penetration of these X-rays is related to the atomic weight of the element
1909 Hans Geiger and Ernest Marsden discover large angle deflections of alpha particles by thin metal foils
1924 Louis de Broglie suggests that electrons may have wavelike properties in addition to their 'particle' properties; the wave–particle duality has been later extended to all fermions and bosons.
1942 Enrico Fermi makes the first controlled nuclear chain reaction
1942 Ernst Stueckelberg introduces the propagator to positron theory and interprets positrons as negative energy electrons moving backwards through spacetime
1982 Alain Aspect, J. Dalibard, and G. Roger perform a polarization correlation test of Bell's inequality that rules out conspiratorial polarizer communication
^Yndurain, Francisco Jose; Quantum Chromodynamics: An Introduction to the Theory of Quarks and Gluons, Springer Verlag, New York, 1983. ISBN0-387-11752-0
^Weinberg, Steven; The Quantum Theory of Fields: Foundations (vol. I), Cambridge University Press (1995) ISBN0-521-55001-7. The first chapter (pp. 1–40) of Weinberg's monumental treatise gives a brief history of Q.F.T., pp. 608.
^Weinberg, Steven; The Quantum Theory of Fields: Modern Applications (vol. II), Cambridge University Press:Cambridge, U.K. (1996) ISBN0-521-55001-7, pp. 489.
^Pais, Abraham; Inward Bound: Of Matter & Forces in the Physical World, Oxford University Press (1986) ISBN0-19-851997-4 Written by a former Einstein assistant at Princeton, this is a beautiful detailed history of modern fundamental physics, from 1895 (discovery of X-rays) to 1983 (discovery of vectors bosons at C.E.R.N.)