Very good fun even if I stopped getting it properly somewhere in the middle.

(PS, the c quark is called charm)

In all honesty, most of this book was over my head. But I enjoyed Feynman's sense of humor throughout. If you like physics, this is a good, quick read that's both entertaining and informative.

what they say is true, this guy sure can talk about physics

the first chapter was defo my fav the rest was just like a whistle stop tour of particle physics, which ig is what a lot of people are looking for in popular science books

Jednou se k té čtvrté kapitole budu muset znovu vrátit... Ale Feynmanův důvtip je k nezaplacení! :)

I had high expectations of this book given Richard Feynman's reputation as a genius communicator. All started well, he had a style that got to the point very effectively and led you through the problems of light reflecting all the way to how quantum electrodynamics explains how lenses work. There were some issues on the way that, as with many popular science books, you just had to accept - like why are the arrows he uses to analyse situations the square root of the probablity of an event (confusingly called the amplitude) and not just the probability? Anyway, the book went on to electrons and things got a little trickier, the book became so dense with information that not taking in certain bits meant subsequent passages became much harder to grasp. Finally we reached nuclear physics, which, to be fair, he said was a mess and that's how it came across. But, because this was a short book, it seemed worth the effort just to reread it and, lo and behold, so much more made sense, it really was extraordinary and it suddenly became apparent what he was driving out. I would still struggle to explain QED to anyone but I do feel it gave me insights into the subject that I had missed in other books on the subject. So yes, QED, so good I read it twice.

Richard Feynman's theory of quantum electrodynamics is a comprehensive scientific achievement which elaborates nature's most intriguing processes and turns them into concepts fathomable for the human mind. Even though the author has toned down the mathematical aspect of the theory significantly, for a non-expert reader it might be hard to follow in certain segments. Especially if one is not used to think in a quantum mechanical framework. However, if the reader is indeed somewhat familiar with such concepts, an in-depth discussion about the world's phenomenona unravels in front of them and a new way of thinking is introduced, which excites and challanges one to think and apply the introduced concepts immediately. Highly recommend it!

What a strange brain Richard Feynman had! While I don't do quantum electrodynamics (QED), I've been studying light/matter interactions for like 15 years via non-linear optics and spectroscopy. The way Feynman approaches these processes on a conceptual level is unique and enlightening.

Simplifying quantum processes for a semi-general audience is pretty much impossible so Feynman deserves points for even attempting it. Some sections, such as his description of how a focusing lens works, were brilliant and useful for every student of optics. In others, however, he seemed to get lost in the weeds. His section on positrons, for example, was a challenging read.

Overall, I really enjoyed reading this classic. I wouldn't recommend it for laypeople, but those of us who have suffered through college and/or grad level physics...definitely.

4.5/5.0

This book hits all the marks for a great novel. Yes, it's a science book, but it's probably one of the best ones I've read so far. Feynman has a fun style of writing and makes these topics very easy to understand. He really captures the wonder and excitement that new things in physics can offer. Even though I knew many of the things in the book already, I had never seen them presented in this way before, as in, explaining common phenomena like reflection and diffraction with the little "arrows" (which are actually imaginary numbers represented in the complex plane. I wouldn't have figured that out if the person who wrote the intro hadn't pointed it out though). I often thought "oh! so that's what's going on!" and "why on Earth didn't they teach it this way in school?" Though it does seem deceptively simple when you read it, and I know that there is much more going on "behind the curtain" that only the physicists know about.
The first 2 chapters are on QED (quantum electrodynamics): the first on photons, the second on electrons, and the third chapter is on quantum chromodynamics (ie. the strong force with quarks and co.). The theory of QED is one of the few (the only?) theory that's pretty much completely known in physics with regards to experiment aligning with theory. We see in the last chapter just how much of a "mess" particle physics is in general, though I found this last part really interesting. I think we have figured out more things to sort out the mess since this book has been written, but there are certainly still challenges to overcome.
The diagrams in the book were simple and illustrative, and made me glad that I got the print copy as opposed to the audiobook (they were lectures, but I assume there must have been slides too, because you really need to see the diagrams).
I'd recommend this book to anyone interested in science and especially physics. I wouldn't say it is a book for the "general public", since some parts might be a bit too complicated, but anyone with at least high school physics should have no problem (though I'm biased, since I'm doing physics at university, so I might be wrong about that). Although this was written (or rather, the lectures were given) many decades ago, it still forms the basis of our understanding of QED, and Feynman diagrams and the little arrows are still used in physics all the time.
The only downside of the book is that since these were 3 lectures, they are split into 3 humungous chapters, and it would have been better to have smaller chapters. Nevertheless, I really enjoyed this book and at the same time I could laugh out loud as well as learn lots as I read it.

Feynman si dimostra straordinariamente efficace nella spiegazione di fenomeni alquanto complessi quali le dinamiche dell'elettrodinamica quantistica ad un pubblico di non specialisti.

Ho approcciato questa lettura dopo aver osservato che vari autori (C.J.S. Clark, S. Hameroff and R. Penrose, H. Stapp, D. Bilodeau, W. Seager) utilizzano il funzionamento della meccanica quantistica per spiegare il funzionamento della coscienza, e senza dubbio spesso in maniera estremamente speculativa.

Feynman ricorda: “Io descriverò il comportamento della Natura, ma se a voi questo comportamento non piace, il vostro processo di comprensione ne risulterà intralciato. I fisici hanno imparato a convivere con questo problema: hanno cioè capito che il punto essenziale non è se una teoria piaccia o non piaccia, ma se fornisca previsioni in accordo con gli esperimenti. La ricchezza filosofica, la facilità, la ragionevolezza di una teoria sono tutte cose che non interessano.”
Le speculazioni filosofiche, benchè da un punto di vista fisico abbiano ben poco senso, e si dimostrino pertanto non giustificabili alla luce del generale approccio 'naturalista' sotto la cui egida opera la maggior parte dei filosofi contemporanei, si incentrano spesso sul principio di indeterminazione di Heisenberg, preso come fondamento di sviluppi ontologici random e non-deterministici.
Con l'ingresso in campo della meccanica quantistica, certamente non possiamo più prevedere esattamente come si comporterà qualsiasi particella di un qualsiasi fenomeno. C'è sempre una variabile di indeterminazione del modello di predizione, ed è risultato estremamente resistente a qualsiasi attacco. Il principio di indeterminazione risulta necessario fino a quando si cerca di spiegare i fenomeni quantistici alla luce di vecchi concetti, quali sono la contemporanea esattezza della misurazione della posizione e del moto. Poichè però la meccanica quantistica inserisce esplicitamente - forse a malincuore, ma come unica spiegazione possible - la probabilità come unico fattore di spiegazione dei fenomeni, il principio di indeterminazione non sussiste in maniera così stretta, e possiamo parlare di misurazioni con un grado di esattezza altissimo (p.77; Feynman usa un'immagine molto efficace: la differenza tra il valore accertato sperimentalmente e quello teorizzato del momento magnetico dell'elettrone, ad esempio, è accurato nella stessa misura per cui "la distanza tra New York e Los Angeles, di quasi 5.000 km, fosse misurata con l'approssimazione di un capello umano.")

Contrariamente a certe altre mistificazioni riscontrabili in alcune aree della letteratura, secondo le quali vi sarebbe un cambio di stato di applicabilità delle leggi fisiche, come tra le leggi Newtoniane e quelle quantistiche, con conseguente allusione alla possibilità di inserire nuove leggi per spiegare fenomeni ancora lontani dalla nostra comprensione, è estremamente utile ricordare che le prime sono semplicemente un’utile semplificazione delle seconde, per quanto concerne dimensioni superiori all’atomo. In QED, Feynman dimostra con una facilità disarmante come l'elettrodinamica quantistica spieghi fenomeni ordinari quali la rifrazione della luce, i miraggi, la trasmissione della luce in linee rette, il funzionamento delle lenti convergenti...

Insomma, come Sean Carroll ha abilmente argomentato nel suo bel 'The Big Picture', non abbiamo davvero bisogno di altro che le leggi della quantistica per spiegare il mondo a noi circostante (l'eccezione sta nel fatto che il modello esclude le interazione ultra-deboli come l'effetto gravitazionale e alcune possibili conseguenze della materia oscura. Tali eccezioni sono tuttavia incluse nel modello, e possiamo aspettarci delle sorprese solamente al di fuori del suddetto campo di applicabilità)

È auspicabile chiederci il perchè delle cose, in ciò risiede la bellezza e la forza della condizione umana. Quando tale ricerca diverge però da un quadro naturalista, abbiamo ottime ragioni per credere che si tratti dell'approccio sbagliato. "Nature does not know what you are looking at, and she behaves the way she is going to behave whether you bother to take down the data or not." (Richard Feynman)

QED, by Richard Feynman, a distinguished theoretical physicist, introduces the quantum world to the layman gently but effectively and accurately. Within his first lecture, he briefly introduces key concepts of QED, such as taking the square of an amplitude to find a probability, or the way that photons behave in the presence of electrons. This acts as a fairly succinct chapter introducing a mindset necessary for the comprehension of more advanced materials, which follow, in the later lectures. In his second and third lectures, he applies the previously demonstrated concepts to an example, the reflection of light from a pane of glass, as well as introducing new concepts, such as Heisenberg’s Uncertainty Principle, as well as constructive and destructive interference. In his final lecture, titled “Loose Ends”, he connects quantum electrodynamics to the rest of physics, tying in concepts such as the strong and weak forces, as well as discussing the meaning of quantum electrodynamics, and some of its problems, I enjoyed this book thoroughly, as it was written in a simple manner, while still being able to explain complex concepts. I would recommend it to anyone curious about the subject matter, as it serves as an excellent introduction to the quantum world, giving the reader a good idea of what to expect if they should further pursue the subject, while still being appropriate for an introduction to quantum physics.

Richard Feynman's friend Alix had asked him to explain Quantum Electrodynamics (the titular QED) to her in a way a layman could understand many times. Heartbreakingly, it wasn't until her death that he actually found the time to write a series of four lectures that would do just that. This book is a (slightly edited) transcript of those four lectures.

Feynman writes for the layman without ever being condescending and his famous sense of humour shines through. He makes this subject both approachable and fascinating. I've studied much of the content before in physics classes and other books but Feynman has made me look at it in a different way. In fact, I can safely say that this book has significantly changed the way I think about reality.

If that's not worth five stars, nothing is. If you've not read this book before, do yourself a favour and give it a bash.