Einstein’s Impact on Theoretical Physics in the 21st Century

1. Einstein’s Impact on Theoretical Physics in the 21st Century

2. Einstein was the greatest physicist of the 20th century. • And with Newton the two greatest physicists of all times.

3. Depth • Scope • Imagination • Persistence • Independence

4. The 20th century was a great century for fundamental physics. It witnessed 3 profound conceptual revolutions, of which Einstein personally created two, and greatly contributed to the third.

5. 1. First revolution: • Special Relativity (1905)

6. Einstein as patent clerk, ca. 1905

7. 1887 Michelson-Morley • Lorentz (1853-1928) • Poincare (1854-1912) • Fitzgerald (1851-1901) • Lamor (1857-1942)

9. Revolution in the • concept of simultaneity

10. Lorentz wrote in 1915 (Pais p. 167): • “The chief cause of my failure was my clinging to the idea that only the variable t can be considered as the true time and that my local time t' must be regarded as no more than an auxiliary mathematical quantity.”

12. Poincare in 1904 • (In <Physics for a New Century> AIP publication on History, volume 5, 1986)

13. “The principle of relativity, according to which the laws of physical phenomena should be the same, whether for an observer fixed, or for an observer carried

14. along in a uniform movement of translation; so that we have not and could not have any means of discerning whether or not we are carried along in such a motion.”

15. Lorentz had the mathematics. • Poincare had the philosophy. • But neither had the physics.

16. Einstein’s special relativity • revolutionized the concept of space, time, motion and energy, • clarified the meaning of Maxwell’s equations, • introduced the concept of symmetry into fundamental physics.

17. This symmetry is called Lorentz symmetry and is of central importance in contemporary physics. E.g. the renormalization program is built upon the intrinsic use of this symmetry.

18. Symmetry, its generaliza-tions and variations, will remain one of the key concepts in the theoretical physics of the 21st century.

19. The five regular solids with maximum symmetry. Reprinted from A.V. Shubnikov and V.A. Koptsik, Symmetry in Science and Art (Plenum, 1974).

20. Symmetry • 1905 Einstein • 1908Minkowski

21. “Superfluous learnedness”

22. In Yang: Klein Memorial Lecture, p. 23, • “… in 1982, in a conversation in Erice, Italy, Dirac (1902-1984) asked me what I thought was Einstein’s most important contribution to physics. I answered, “General relativity of 1916.”

23. Dirac said, “That was important, but not as important as his introduction of the concept that space and time are symmetrical.” What Dirac meant was that while general relativity was singu-larly profound and original,

24. the symmetry of space and time has more pervading immediate influence on later developments.”

25. 2. Second revolution: • General Relativity (1916)

27. Lanczos in The Einstein Decade, 1915-1925: (p. ix) • “The magic of his personality imposed itself on almost everybody who came in touch with him.”

28. Wigner in Woolf 1979, p. 461: • “The physics colloquia acquainted us with the clarity of Einstein’s thinking, with his simplicity and modesty, and also with his skill of exposition.”

29. General Relativity was a singularly profound creation by Einstein. It was motivated by 2 ideas: • Equivalence principle • Very large invariance • (or symmetry)

30. “… that the basic demand of the special theory of relativity (invariance of the laws under Lorentz-transformations) is too narrow, i.e. that an invariance of the laws must be postulated also relative to non-linear transformations

31. of the coordinates in the four-dimensional continuum. • This happened in 1908.” • Einstein: Autobiographical Notes • in <Albert Einstein>, ed. P.A. • Schilpp, p.67

32. Influence of General Relativity: • Cosmology (1917) • Speculations on quantum • gravity • Geometry • Unified field theory

33. All of these influences will continue in force in the 21st century.

34. 3. Third revolution: • Quantum Theory • (1900-1925)

35. Planck • Einstein Bohr • de Broglie Heisenberg • Schrödinger Born

37. Bose-Einstein Statistics • 1924-1925 • Bose-Einstein Condensation • 1925

38. Bose-Einstein Condensation is now the hottest topic in physics, with enormous potential for future applications.

39. Einstein was giving a lecture in 1922 at the College de France in Paris

40. Einstein’s “obsession” • with unified field • theory

41. Einstein in Princeton

42. “There was never any attempt by him to browbeat us. He made us feel extremely comfortable intellectually and emotionally.” • Hoffmann, Woolf p. 476

43. Einstein & Franklin Yang (Princeton,1954)

44. Rabi in Woolf volume (1979): • “When you think of Einstein’s career from 1903 or 1902 on to 1917, it was an extraordinarily rich career,

45. very inventive, very close to physics, very tremendous insights; and then, during the period on which he had to learn mathematics, particularly differential geometry in various forms, he changed.

46. He changed his mind. That great originality for physics was altered …..”

47. Did Einstein change?

48. Was his originality for physics altered?

49. “it was not clear to me as a student that the approach to a more profound knowledge of the basic principles of physics is tied up with the most intricate mathematical methods.”

50. Einstein, from the beginning, was fully concentrating on the basic principles of physics.