• .

  • 

  • A book aims at a non-technical audience -- you can probably understand it if you can do arithmetic without using a calculator. (An ability that has become less-than-common these days, I realize.) Therefore it is not listed under my "intimidating physics books" section.

    The book is about Quan ... Continue

    A book aims at a non-technical audience -- you can probably understand it if you can do arithmetic without using a calculator. (An ability that has become less-than-common these days, I realize.) Therefore it is not listed under my "intimidating physics books" section.

    The book is about Quantum ElectroDynamics, QED for short, a theory Feynman himself has contributed a lot to. It is a quantum description of the electromagnetic field, and how it interacts with matters carrying electric charge.

    Feynman attempted to give an intuitive picture to everything he talked about. His usual style. And he is largely successful, although sometimes pictures he painted, while being technically correct, are very far from how people actually deal with the problem.

    With one exception, though.

    Near the end of the book, he described some then unsolved mysteries surrounding QED. Back then one of the biggest problems bugging physicists for years was those annoying infinities you get for virtually any calculation in QED.

    Sure, there are ways ("renormalization", we call it) to get rid of these infinities -- but back then it wasn't so clear to physicists if this renormalization procedure is legitimate at all.

    (There is a cartoon, still to be seen on the wall somewhere in every particle theory group's office space, making fun of how people "sweep all the infinities under the rug".)

    Feynman of course wrote about this issue in the book, and said that the need of renormalization signifies something's not right.

    Well, the general view on this issue changed during the '70s; the meaning of renormalization was re-interpreted by Kenneth Wilson. It is not to be thought of as just an exercise to remove "unphysical" infinities. But rather we admit that our theory is incomplete; it is going to fail when we push it to the extreme short-distance limit. The infinities signal the failure of the theory, and before we know what lies beyond (which we still don't), the sensible thing to do is to cut away this extreme limit.

    Can't foul Feynman for not knowing the future development when he wrote the book. But just want to point out that his take on this issue is somewhat outdated.

    

    Is this helpful?

• ― pthow said on Apr 12, 2007 | Add your feedback

Famous the world over for the creative brilliance of his insights into the physical world, Nobel Prize-winning physicist Richard Feynman also possessed an extraordinary talent for explaining difficult concepts to the nonscientist. QED--the edited version of four lectures on quantum electrodynamics that Feynman gave to the general public at UCLA as part of the Alix G. Mautner Memorial Lecture series--is perhaps the best example of his ability to communicate both the substance and the spirit of science to the layperson.

The focus, as the title suggests, is quantum electrodynamics (QED), the part of the quantum theory of fields that describes the interactions of the quanta of the electromagnetic field-light, X rays, gamma rays--with matter and those of charged particles with one another. By extending the formalism developed by Dirac in 1933, which related quantum and classical descriptions of the motion of particles, Feynman revolutionized the quantum mechanical understanding of the nature of particles and waves. And, by incorporating his own readily visualizable formulation of quantum mechanics, Feynman created a diagrammatic version of QED that made calculations much simpler and also provided visual insights into the mechanisms of quantum electrodynamic processes.

In this book, using everyday language, spatial concepts, visualizations, and his renowned "Feynman diagrams" instead of advanced mathematics, Feynman successfully provides a definitive introduction to QED for a lay readership without any distortion of the basic science. Characterized by Feynman's famously original clarity and humor, this popular book on QED has not been equaled since its publication.

• ScienceTheoretical PhysicsFeynmanPhysicsEssayNon-fiction