Richard Phillips Feynman (1918 - 1988), was an American theoretical physicist who was widely regarded as the most brilliant, influential, and iconoclastic figure in his field in the post-World War II era. Feynman shared the 1965 Nobel Prize in Physics with Shinichiro Tomonaga and J. S. Schwinger for work leading to the establishment of the modern theory of quantum electrodynamics. The problem-solving tools that he invented--including pictorial representations of particle interactions known as Feynman diagrams--permeated many areas of theoretical physics in the second half of the 20th century.
During World War II Feynman was recruited to serve as a staff member of the U.S. atomic bomb project at Princeton University (1941–42) and then at the new secret laboratory at Los Alamos, New Mexico (1943–45). At Los Alamos he became the youngest group leader in the theoretical division of the Manhattan Project. With the head of that division, Hans Bethe, he devised the formula for predicting the energy yield of a nuclear explosive.
After World War II, in the autumn of 1945, Feynman was appointed as a professor of theoretical physics at Cornell University. In 1950 Feynman accepted a position as professor of theoretical physics at the California Institute of Technology. He remained at Caltech for the rest of his career, being appointed Richard Chace Tolman Professor of Theoretical Physics there in 1959.
Five particular achievements of Feynman stand out as crucial to the development of modern physics. First, and most important, is his work in correcting the inaccuracies of earlier formulations of quantum electrodynamics, the theory that explains the interactions between electromagnetic radiation (photons) and charged subatomic particles such as electrons and positrons (antielectrons). By 1948 Feynman completed this reconstruction of a large part of quantum mechanics and electrodynamics and resolved the meaningless results that the old quantum electrodynamic theory sometimes produced. Second, he introduced simple diagrams, now called Feynman diagrams, that are easily visualized graphic analogues of the complicated mathematical expressions needed to describe the behavior of systems of interacting particles. This work greatly simplified some of the calculations used to observe and predict such interactions.
In the early 1950s Feynman provided a quantum-mechanical explanation for the Soviet physicist Lev D. Landau's theory of superfluidity--i.e., the strange, frictionless behavior of liquid helium at temperatures near absolute zero. In 1958 he and the American physicist Murray Gell-Mann devised a theory that accounted for most of the phenomena associated with the weak force, which is the force at work in radioactive decay. Their theory, which turns on the asymmetrical "handedness" of particle spin, proved particularly fruitful in modern particle physics. And finally, in 1968, while working with experimenters at the Stanford Linear Accelerator on the scattering of high-energy electrons by protons, Feynman invented a theory of "partons," or hypothetical hard particles inside the nucleus of the atom, that helped lead to the modern understanding of quarks.
Feynman's stature among physicists transcended the sum of even his sizable contributions to the field. His bold and colorful personality, unencumbered by false dignity or notions of excessive self-importance, seemed to announce: “Here is an unconventional mind.” He was a master calculator who could create a dramatic impression in a group of scientists by slashing through a difficult numerical problem. His purely intellectual reputation became a part of the scenery of modern science. Feynman diagrams, Feynman integrals, and Feynman rules joined Feynman stories in the everyday conversation of physicists. They would say of a promising young colleague, “He's no Feynman, but….” His fellow physicists envied his flashes of inspiration and admired him for other qualities as well: a faith in nature's simple truths, a skepticism about official wisdom, and an impatience with mediocrity.
Above all, in and out of science, Dr. Feynman was a curious character - his phrase, and the double meaning was intentional. He was never content with what he knew or what other people knew. He taught himself how to fix radios, pick locks, draw nudes, speak Portuguese, play the bongos and decipher Mayan hieroglyphics.
He pursued knowledge without prejudice, studying the tracking ability of ants in his bathtub and learning enough biology to study the mutation of bacteriophages.
Feynman's popular lecture series was published in The Feynman Lectures, while his personal side was captured in Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?
References in The Big Bang Theory
In "The Guitarist Amplification", Sheldon recalls blaring The Feynman Lectures on Physics when upset about his parents fighting, "I’ve heard that before, but then, the next thing you know I’m hiding in my bedroom, blaring a Richard Feynman lecture while my mom is shouting that Jesus would forgive her if she put ground glass in my dad’s meatloaf, and my dad’s on the roof skeet-shooting her Franklin Mint collectible plates."
In "The Einstein Approximation", Sheldon finds a menial job as a busboy at The Cheesecake Factory so that his basal ganglia are occupied with a routine task, freeing his prefrontal cortex to work quietly in the background on his problem. He drops a tray of plates and a nearby table claps, with Sheldon stating: "Is that really necessary? Good Lord. The interference pattern in the fracture...The motion of the wave through the molecular structure...I’ve been looking at it all wrong. I can’t consider the electrons as particles. They move through the graphene as a wave. It’s a wave!" After observing a wobbling plate in the Cornell University cafeteria, Feynman similarly had an epiphany regarding the motion of electrons. By a mathematical coincidence, the equation that describes electron motion in graphene is almost the same as the fundamental equation of free electrons in relativistic quantum mechanics: the famous Dirac equation.
In "The Zazzy Substitution", Sheldon names his clowder of cats after Manhattan Project physicists and one of his cats is dubbed Richard Feynman.
In "The Skank Reflex Analysis", the apartment whiteboards near the entry way and behind Sheldon's desk feature Feynman diagrams illustrating the capacity of electrons to produce axions in very dense environments at high temperatures (e.g., the Sun's core).
In "The Vacation Solution", Sheldon takes a cue from Richard Feynman and dabbles in biology at Amy's lab. Sheldon states, "One time they tried to make Richard Feynman take a vacation, but he chose instead to expand his mind and learn something new. He went to work in his friend’s biology lab."  He explains to Howard in a condescending tone, "Richard Feynman was a famous American physicist, part of the Manhattan Project," to which Howard musters, "Everyone in the world of science knows who Richard Feynman was."  Sheldon continues, "Now you do, too. Oh! I have a brilliant idea. Amy’s a biologist. I’ll go work in her lab." Then, Howard pushes, "Isn’t that just Feynman’s idea?"
Sheldon decidedly completes the conversation, "Ten seconds ago, you never heard of him. Now you’re an expert."
In "The Werewolf Transformation", Sheldon takes up playing the bongos just like Feynman did. He mentions this and Leonard tries to explain who he is to Penny at 3 AM ("a famous physicist"); Penny doesn't care if Feynman were a purple leprechaun living in her butt.
In "The Bachelor Party Corrosion, the gang borrows his real minivan for a road trip to Mexico, have a flat tire and end up setting it on fire.
- In his eccentric collection of autobiographical stories (see “Surely You’re Joking, Mr. Feynman!”), Richard Feynman recounts: "I was in the cafeteria and some guy, fooling around, throws a plate in the air. As the plate went up in the air I saw it wobble, and I noticed the red medallion of Cornell on the plate going around. It was pretty obvious to me that the medallion went around faster than the wobbling. I had nothing to do, so I start figuring out the motion of the rotating plate. I discovered that when the angle is very slight, the medallion rotates twice as fast as the wobble rate—two to one. It came out of a complicated equation! I went on to work out equations for wobbles. Then I thought about how the electron orbits start to move in relativity. Then there's the Dirac equation in electrodynamics. And then quantum electrodynamics. And before I knew it… the whole business that I got the Nobel prize for came from that piddling around with the wobbling plate."
- Late in his life, he [Feynman] and his friend Ralph Leighton decided to travel to a place called Tannu Tuva, a small country in the exact geographical center of Asia, a remote place where throat-singers sang with two voices at once, and reindeers and camels roamed free. For years they negotiated with the Soviet government to let them travel there. Meanwhile they studied the language, wrote letters to Tuvans, and practiced throat-singing. They even set up an exhibition of Tuvan art at the LA County Museum of Natural History, hoping to travel back to Tuva with the art. The Soviets were slow at best, and uncooperative at worst. And Feynman's health was deteriorating. A couple weeks after Feynman's death in 1988, his wife received an invitation from the USSR Academy of Sciences to visit Tuva.
- Feynman spent the summer of 1960 in Max Delbrück|Delbrück's lab at Caltech and discovered intragenic supression. This is where the expression of a gene which has been knocked out by a mutation may be restored by a second mutation within the same gene. Fenynman worked with the rII mutant of phage T4 and was looking for back mutations in E.coli strain K. He noted some unusual plaques which he labelled "idiot r's". Feynman correctly deduced that these revertants were due to a second mutation which cancelled the effect of the first, but he did not publish the result, possibly because he had no molecular explanation for what was going on. The Delbrück lab referred to these revertants as "Feyntrons".
- Although his handiwork permeates the foundations of modern science, millions of Americans heard his name for the first time in 1986, when he brought an inquisitive and caustic presence to the Presidential commission investigating the explosion of the space shuttle Challenger. Early on, he stunned a Washington hearing room by calling for ice water, plunking in a piece of the critical O ring seal from the rocket booster and then pinching it with a small clamp. It was a turning point in the investigation - a simple experiment, taking half a minute and no money, that perfectly demonstrated both the vulnerability of the seal and the absolute confidence of the experimenter.
- His most famous books, collections of autobiographical anecdotes and aphorisms— “Surely You’re Joking, Mr. Feynman!” (1985) and What Do YOU Care What Other People Think? (1988)—stemmed from tape-recorded, bongo-playing jam sessions with his friend, Ralph Leighton (the son of one of his Caltech colleagues).