Richard Feynman : A Unique Path

Richard Feynman: A Unique Path

From a child to a world-famous scientist

Outline

• Life

• Science

• Teaching

Life• Born: May 11, 1918 in New York City

Milleve Feynman: “… If it's a boy, he's going to be a scientist… “

• Early Education: bored with humanity, history, literature, found spelling “illogical”…;deeply influenced by his fathermet a few good teachers (Mr. Bader,…)

• College: Graduated from MIT (Senior thesis: “Forces and stresses in molecules”

advisor: John C Slater)

Life…cont’d

• Graduate School: Princeton (1939-1942) Thesis: “ The least action principle in quantum mechanics ” (Adviser: John A Wheeler)

• First marriage: to Arlene Greenbaum (1942-1945)• Manhattan project: Los Alamos (1943-1946)• Cornell Physics Faculty: 1946-1951 • Caltech: Tolman Professor of Physics (1951-death)

Life…cont’d

• A letter written two years after Arlene’s death:

“…I adore you sweetheart. . . I have met many nice girls, and I don't want to remain alone-but in two or three meetings they all turn to ashes. You only are left for me. You are real. My darling wife, I adore you….”

“…Please excuse me for not mailing this-but I don't know your new address."

Life…cont’d

• Second marriage: to Mary Louise Bell (1952-1956)

“He begins working calculus problems in his head as soon as he awakens. He did calculus while driving in his car, while sitting in the living room, and while lying in bed at night.”—Mary Louise Bell divorce complaint

• Third marriage: to Gweneth Howarth (1960- ) son (Carl, 1962) daughter (adopted Michelle, 1968)

Life…cont’d

Feynman on his children:

“I always thought I would be a specially good father because I wouldn’t try to push my kids into any particular direction. I wouldn’t try to turn them into scientists or intellectuals if they didn’t want it. I would be just as happy with them if they decided to be truck-drivers or guitar-players. In fact I would even like it better if they went out in the world and did something real instead of being professor like me. But they always find a way to hit back at you. My boy Carl for instance. There he is in his second year at MIT, and all he wants to do with his life is to become a god-damned philosopher!”

Life…cont’d• Nobel prize: 1965 with Schwinger and Tomonaga (contribution

to QED)

• Other recognitions: member of the National Academy of Science; foreign member of the Royal Society, London (Great Britain); Albert Einstein Award (1954, Princeton); Einstein Award (Albert Einstein Award College of Medicine); Lawrence Award (1962).

• Feynman on honor http://www.youtube.com/watch?v=f61KMw5zVhg&feature=player_embedded#!

Life…cont’d

• Last part: illness, Challenger, and death• 1978: first diagnosed with liposarcoma, underwent

operation• 1981: cancer returned, more operation• 1986: The Challenger incident committee "For a successful technology, reality must take

precedence over public relations, for nature cannot be fooled.”

• 1988 (Feb. 15): woke from a coma”…I’d hate to die twice. It’s so boring….”

Feynman’s carelessness for formality(Photo: with other Caltech Nobel Laureates)

Science

• Path integral formulation of QM (1942):

<xA, tA|xB, tB> ~ S(path) exp(2iS/h)

• Bohr’s objection: Feynman, you are crazy…

Science…cont’d

• Feynman diagram (1948)

The Feynman diagram of the term

Science…cont’d• Feynman-Hellman Theorem

• Undergraduate thesis (1939, MIT)• Most-cited paper of Feynman (> 1800 times!)

Science…cont’d• V-A Theory (1958) (Feynman, Gellman, Marshak, Sudarshan)

The first correct theory of Weak Interaction“…the only law of Nature I could lay a name to…”

Science…cont’d• Geometric Model for Laser Operation (his only work in applied physics)

(Feynman, Vernon, Hellwarth: Joun. Appl. Phys., 1957)

• Complete analogy to dynamics (Block Equation) of NMR• Leading to “Optical Bloch Equation” in Quantum Optics

Science…cont’d• Theory of Superfluid Helium (1953-1958)

Feynman (1954)Feynman and Cohen (1956): path integral → partition function

Science…cont’d

• Nanotech Pioneer: “There’s plenty of room at the bottom…(1959)

“…When we get to the very, very small world -…completely new opportunity for design. Atoms on a small scale…obey the laws of quantum mechanics…., and we can expect to do different things….We can use,…system involving quantized energy level, or interactions of quantized spins, etc.”

Inspiration from biological systems: “ so much information is contained in so tiny spatial volume (that of a cell) …”

The Feynman prizes: $1000 for building a motor of 1/64 inch cubed $1000 for shrinking the info of a page of a book by 1/25000 times, and read it with an electron microscope

Science…cont’d

• Pioneer of Quantum Computing P. A. Benioff : “ The computer as a physical system: a

microscopic Hamiltonian model of computers as represented by Turing machines ” (1981)

R. P. Feynman : “ Simulating physics with computers ” (1982) – “…because Nature is not classical, dammit, and if you want to make a simulation of Nature, you’d better make it quantum mechanical…”

R. P. Feynman : “Quantum mechanical computers” IQEC/CLEO (1984); Opt. News (1985); Found. Phys. (1986) ---

ideas of quantum bits (2-state atoms) and quantum gates

Feynman and the Connection Machine

Science…cont’d

• Contribution in biology (genetics):

Teaching (Is Feynman a “good” teacher?)

• Feynman Lectures on Physics (1961-1963)

Teaching,…cont’d

• Great Explainer: explanation to layman…• Diagrams, analogies, gestures, actions,…

“Something I cannot create I do not understand”

"Teaching and students keep life going, I would never accept a position in which somebody has invented a happy situation for me where I don't have to teach. Never."

• Challenge: Pauli’s Exclusion Principle

http://www.youtube.com/watch?v=2OU_f7vYDys&feature=related

Lecture on “Scientific Method” at Cornell (1964)

• http://www.youtube.com/watch?v=EYPapE-3FRw&feature=related

Teaching,…cont’d

• An address to high school teacher (1966)• Question: What is ?

= s1/d1 = s2/d2 = s3/d3 =…

Richard Feynman on God

• http://www.youtube.com/watch?v=YltEym9H0x4&NR=1&feature=endscreen