What did Richard Feynman contribute to physics?
April 13, 2019 1:32 PM   Subscribe

I recently read a collection of Feynman's non-scientific essays. Eager to know more about his scientific work, I went to Wikipedia, did some Google searches etc, but found that even simplified explanations of his work were beyond my knowledge. The path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquids, the parton model he proposed for particle physics: I'm in dark across the board. Can anyone shed any light? Thanks
posted by BadgerDoctor to Science & Nature (7 answers total) 7 users marked this as a favorite
Quora: What work of Richard Feynman won him the Nobel prize?:

> In 1948, Richard Feynman contributed to creating a new quantum electrodynamics by introducing Feynman diagrams: graphic representations of various interactions between different particles. These diagrams facilitate the calculation of interaction probabilities.

The wikipedia page on Feynman diagram has more, including a discussion of the path integral formulation.

I am not sure how else to answer your question. If you are looking for an overview, wikipedia has it. If you are looking for a deep understanding, you could try something more like MIT's Open Courseware Quantum Physics I?
posted by richb at 1:54 PM on April 13, 2019

There is some interesting discussion of his work on the Sotheby's auction page where his Nobel Prize was sold.
posted by richb at 1:57 PM on April 13, 2019 [1 favorite]

Feynman himself wrote a book explaining his quantum electrodymanics work to non-scientists: QED: The Strange Theory of Light and Matter
posted by JonJacky at 2:08 PM on April 13, 2019 [5 favorites]

In addition to his research work and non scientific writings, Feynman was, perhaps, the best physics teacher of the 20th century. The Feynman Lectures on Physics are legendary alternate ways to teach fundamental physical principles.

There is a real difficulty with trying to understand advanced scientific research if you don't have a sufficient background in it. This was described absolutely brilliantly by, well, Feynman.
posted by Betelgeuse at 2:12 PM on April 13, 2019 [5 favorites]

Feynman also contributed to the Challenger Shuttle Disaster investigation by explaining to the folks from Morton Thiokol that a cup of ice water is at 32 degrees Fahrenheit and maybe they wanted to change their (cough) testimony about their O rings being flexible to that temperature. He had placed a sample of their material in the cup of ice water on the dais and it had become inflexible while they were testifying. He used real science to combat fake testimony.
posted by forthright at 4:26 PM on April 13, 2019 [8 favorites]

The biography written by Glieck, Genius: The Life and Science Richard Feynman, has a good explanation of his accomplishments and places them in the context of his life.

He worked on the Manhattan Project and contributed to the atomic bomb's development. Here is his entry at Atomic Heritage. If I were to summarize Feynman's contribution in the most simple terms, as I understand, was to provide the math and methods of predicting the behavior of particles (atomic and sub-atomic). The progress of chemistry and physics is starting with large things and moving to the smaller being pushed forward by the questions of "why" and "how". I always connected the Power of Ten video is how research telescopes in and out through infinity propelled with "why" and "how". So Feynman helped with the "why" and the "how" of a certain set of particles e.g., the transformation of elements in the transition from one to another (nuclear quantum decay)

There are actual physicists and chemists on this board who will put better into words his contribution and why relevant. I am just feebly taking my readings, like you, into understanding.
posted by jadepearl at 5:21 PM on April 13, 2019

Regarding Quantum Electrodynamics (QED), the theory deals with how photons and electrons act and interact with each other. It is, essentially, the fundamental theory of how photons and electrons work.

So photons mean, of course, light and every other type of electromagnetic radiation--radio waves, X-rays, infrared, ultraviolet, visible light, etc etc etc.

Electrons form the outer shell of every kind of atom and molecule and--for that reason--are the primary means by which atoms and molecules of every physical substance interact with other atoms and molecules and also how those things interact with photons, ie, electromagnetic waves.

So interaction among electrons and photons is at the heart of nearly all day-to-day physical phenomena you can imagine. It's not overstating to say that Quantum Electrodynamics is the fundamental explanatory theory of nearly everything you have ever experienced in your life.

A few examples:

- You look at a cottage cheese carton and see different colors on the label. The colors are produced by light photons interacting with electrons in the chemicals on the surface of the carton and producing other photons of certain energy and direction (all determined by QED) which then travel to your eye (again QED), interact with the lens of your eye to focus (QED), interact with molecules in your retina (QED), causing nerve impulses to form (QED is the fundamental basis of every chemical interaction, including organic chemistry), etc etc etc.

- The fact that the cottage cheese carton can hold its shape is due to the way the molecules of the material in the carton interact with each other to create rigidity, which is due to the interactions of the molecules' electron shells with each other (QED).

- You are reading this on some type of computer screen. At the basis of every type of oscilloscope, TV, cathode-ray tube, LED display, etc etc etc are various forms of interactions between photons and electrons (QED) to create the visible light (QED) you see (QED).

- When your fingers touch your computer keyboard (or any other physical object interacts with another physical object) it is the electrons in the outermost area of the skin of your fingers interacting with the electrons in the molecules of the keys (QED)--generally through the intermediation of some photons zipping back and forth between them (QED)--that keeps you from just sinking right on through the keyboard and allows you to physically manipulate the keys.

- In general, whenever any physical object interacts with another, it's via the particles and rules of interactions governed by QED. So motors, engines, parachutes, airplanes, thunderstorms, firearms.

- Electricity

- How X-rays interact with matter--for example, to create the image of your bones etc created by an X-ray machine

- Fire, electric heat, etc

- Crystal structure, structure of solids, fluid dynamics, etc etc etc

- Every chemical reaction and chemical property

I'll stop there. This list could literally go on to list almost every physical phenomenon you are familiar with. QED lies at the heart of all of them--at very close to the most fundamental level.

Understanding QED at the level of detail and precision that became possible in the mid 1900s due to the work of Feynman and the others who worked on it really is one of the crowning achievements of the scientific endeavor.

I will add this caveat: Even though the mechanisms of QED do indeed underlie all of the phenomena of (say) chemistry, it doesn't really mean that you can just crank through a few formulas from QED to derive every possible chemical property. In fact it's still quite difficult to work out in detail the QED formulas of say a few dozen elementary particles. Once you get into systems with hundreds to thousands of particles--let alone the billions, trillions, and so on that make up even the smallest everyday object--it is well beyond the limits of any imaginable computing capacity to "just crank through" the results based only on fundamental principles of QED. So chemistry, for example, was not just replaced as a field by the discovery of QED. Regular methods of research and study of chemistry continue as usual, with perhaps some new insights in place due to a better understanding of some of the fundamental phenomena.
posted by flug at 10:15 PM on April 13, 2019 [14 favorites]

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