The Dirac Equation for the Electron Ferment （狄拉克方程的电子发酵）.pdf

1… The Dirac Equation fo r the Electron A p r i l 13, 2 0 0 7 Physics Theory Seminar W esleyan U niversity M iddletown , Connecticut Dr. Roy Lisker 2… OUTLINE 1. The Dirac equation f or the electron. Translating its symbolism 2. Historical and physical motivations that led Paul Dirac to derive this equation in 1928 3. The Klein-Gordon equation 4. Why search f or a linear version of the Klein-Gordon? 5. A digr ession into the theory of quadratic f orms. 6. Dirac’s f actoring of the Klein-Gordon Equation 7. Consequences of the Dirac equation f or physic 3… Note: Before delivering this lecture I sent copies around to friends and colleagues for suggestions. The following is excerpted from the reply sent by a friend, a physicist living in the neighborhood of Bard College: “Roy: Excellent exposition of the math…. Alas you have botched the history,,, Despite your efforts to the contrary, Dirac did visit Bard (twice)”.. (Comment: In the late 70’s and early 80’s I sent letters to socially designated distinguished intellectuals, including Isaac Bashevis Singer, Paul Dirac and Steven Smale, encouraging them to turn down invitations to spe ak f rom Bard College because it was a bad pl ace. My letter may have had a contributing eff ect on Bashevis Singer’s decision to turn down the College ’s invitation. Inf ormants in the Physics Depar tment let me know that Dirac had taken my letter seriously (We’d met brief ly at the Einstein Centennial Sympos ium in 1979), and made his own investigation. E vidently he concluded (correctly) that academic f ights of par ochial local y okels were not a strong enough inducement to depr ive the entire Hudson Valley region (that por t