Richard Feynman Lecture on Quantum Electrodynamics: QED. 5/8

Part 5: http://www.youtube.com/watch?v=SjsZjk6ClGw
Richard Feynman gives us a lecture on Quantum electrodynamcis, the theory of photons and electron interactions which incorporates his unique view of the fundamental processes that create it. one of the 3 winners of the 1965 Nobel prize in Physics for his work, Feynman is was an expert on quantum mechanics and developed the Path Integral formulation of Relativistic Quantum mechanics, used in Quantum Field Theory, interpreted the Born series of scattering amplitudes as vertices and Green's function propagators in his famous diagrams, the Feynman Diagrams, and also worked on the fundamental excitations in Liquid Helium leading to a correct model describing superfluidity using phonons, maxons and rotons to describe the various excitation curves.
other fields of work include the Feynman-Hellmann Theorem, which can relate the derivative of the total energy of any system to the expectation value of the derivative of the Hamiltonian under a single parameter, e.g volume.
he also worked on the Rogers Commission report during the investigation of the 1986 Space Shuttle Challenger disaster, where Feynman famously demonstrated how the Booster Rocket O-rings, which are elastic sealing joints, became less resilient and subject to seal failures at ice-cold temperatures by immersing a sample of the material in a glass of ice water- his high intelligence and independant way of looking at the world often made him "a real pain" in the eyes of other, less skilled, Commission members.
Feynman's own investigation reveals a disconnect between NASA's engineers and executives that was far more striking than he expected. His interviews of NASA's high-ranking managers revealed startling misunderstandings of elementary concepts, such as safety proceedures.
Although Feynman got plenty of media coverage due to him being on the Commission, he was often told to stay quiet about NASA's more sinister secrets and tactics in space exploration.

Category:

Science & Technology

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• Richard
• Feynman
• Quantum
• electrodynamics
• Field
• Theory
• Mechanics
• photons
• electrons
• electromagnetism
• nuclear
• forces
• fundamental
• physics
• lectures
• QED
• elementary
• particles
• chemistry

[Vape4life]

I kick myself in the ass for not paying attention in math class. I've been trying to get a good handle on quantum theory via books like quantum mechanics for poets and whatnot...and those have actually been pretty good...but i'm fast approaching a wall of knowledge that can only be overcome with full knowledge of math. This is totally fascinating to me...

[MuonRay]

@Vape4life Very little physics can be described without a basic knowledge of math, so you probably have a good level of it already to even appreciate this. however, math taught in schools is probably not even on the level of calculus untill you are in some form of higher education(i could be wrong, i personally taught myself differential calculus at 13 as a means to understand how distance is related to velocity and how velocity is related to acceleration(derivative with respect to time))

[uploadmyvideos123]

@MuonRay Clever you are, thats taught in Mechanics 3 as part of a further maths module in A levels.

[MuonRay]

@uploadmyvideos123 Calculus is the most basic mathematics used in physics; all other physics equations are either extentions or include it in some form. Nevertheless, physics is not pure maths, the maths is purposely engineered to describe the physics behind it, The Schrödinger equation for example is solved so that the wave equation generates non-zero values for integer values of n in the series of sine functions, describing the quantisation of energy seen in a hydrogen atom in the same values.

[dandunleavy]

Love it!

[MuonRay]

@dandunleavy I have recently aquired other videos in this lecture series by Feynman, which go on to describe the further effects on QED.

[TheeVoiceOfReason]

Why hasn't anyone commented this vid?! Feynman was a genius!! I'm trying to study quantum electrodynamics and this vid has one of science's all time greatest showman lecturing on it. Rest in peace Mr. Feynman, I might not have got into physics without you

[cixelsyD1988]

I love how he first states that physics is determined problematically and everyone laughs, but then proceeds to show that that's how it really is. The people who laughed would not have had the imagination to discover qed.

[Hemmersfield1]

i wish i could have been a student even in one of his classes!

[Vape4life]

@MuonRay I actually bought the book he used to teach himself calculus....Calculus for the practical man. Haven't dived into it yet...but wish me luck LOL.

[EquinoxParadox91]

What a wonderful mind!