The guy that wrote the forward for the book seems to dislike Feynman from his personal experience and reputation. For example, he labels Feynman as a philanderer - which was a surprise to me as I was expecting a book more about physics than the physicist.

Feynman is confident and flamboyant in his style, which is easy and enjoyable to read. He also seems exceptionally able to put himself into the mind of a non-expert and explain things appropriately.

The book is based on 4 lectures explaining some 'strange' things about how photons and electrons interact. To compare its difficulty, I found it a lot easier than A Brief History of Time. I also found the first 3 lectures most enjoyable because Feynman slowly works through what he is explaining. The explanations for his figures are really helpful because they reiterate the main text explanations, which gives more opportunity to understand some of the crucial points.

It was only in lecture 4 where he starts to try and cover the remaining 1% of physics that requires 20 times as many particles (I think that is how he expresses his aim for lecture 4), that the book becomes more like reading a physics exam guide with a little humour.

Overall, Feynman has a very readable style and an amazing ability to explain complicated physics.

It's amazing what Feynman is attempting here. He tries to fully explain quantum electrodynamics to people with no background in physics. I am not sure he succeeds, I will have to check it by giving this book to someone who fears the subject.
Even for people like myself, who have been trained in physics, these lectures are useful. The way Feynman clearly communicates the concepts while not diving into mathematics is brilliant. I think these lectures are must read material for aspiring physicists. They show the big picture which is often buried in mathematical detail and remains inaccessible for many students.

Feynman, known for his uncanny ability to describe complex concepts, shines again here with his summary of Quantum Electrodynamics (QED).

Broken into four lectures, the first chapter describes quantum phenomenon in conventional terms, such as reflection and transmission of light, and how these actions can only be described in a probabilistic rather than deterministic way. Feynman argues that quantum mechanics is so unlike classical physics that much of what is to be discussed can only describe the how and not the why.

The second lecture describes Feynman's path integral formalism, which is analogous to the Principle of Least Action in classical mechanics, where sum-over-histories accounts for all possible paths between two points, and the total action becomes the limiting case when summing these quantum actions.

The third lecture introduces the Feynman rules of QED, again illustrating the probability amplitudes accounting for each possible action via higher order perturbation known as propagators, cleverly integrating special relativity. A basic discussion of the rules for electron-photon interactions gives way to the topic of scattering theory and provides the reasoning for why reflection and transmission of light through media is the way we observe.

The final chapter discusses the difficulties of QED when it comes to renormalization yet nonetheless yields results such as the fine-structure constant to a greater accuracy than predicted. A survey of subatomic particles is covered as well, by introducing Quantum Chromodynamics, though it is clear that the top quark, strange quark, bottom quark, and the Higgs hadn't yet entered mainstream physics. Gravity, as today, remains difficult to resolve in a quantum mechanics description due to its incredibly weaker effects when compared to the electromagnetic forces and moreso with the strong nuclear force.

A really satisfying read for non-scientists and an even greater pleasure for those who have studied particle physics or even those who possess a basic knowledge of quantum mechanics.

This book is the edited transcription of a lecture series given by renowned physicist, Richard P. Feynman, at UCLA in 1983. These lectures were designed for an audience of intelligent individuals who are interested in physics but only the good stuff, not the dirty work of slogging through all the math. That said, unless you are a physicist, masochist or perhaps need something to put you to sleep at night this book is not for you.

Feynman in my opinion is one of the greatest physicists of all times, mostly because of his ability to explain just about anything at a level lay people, or at least those like myself with a lowly bachelor's degree in physics, could understand. When I was in college pursuing such I relied heavily on my three volume set of "Feynman's Lectures on Physics" to help me understand certain theories where my college texts failed to explain them sufficiently. Thus, when I obtained this book I expected it to provide a better understanding of quantum electrodynamics than I had previously, which of course was essentially null so it could only increase. That did, indeed, happen, but not to the level I'd hoped for.

Feynman warns his readers right up front in the Introduction on page 9 when he says, "It is my task to convince you not to turn away because you don't understand it. You see, my physics students don't understand it either. That is because I don't understand it. Nobody does."

Great. It was considerate to point out right up front that I would feel either lost or stupid throughout, which certainly proved to be the case. For me even the various diagrams he uses to explain these phenomena (which ultimately became known as Feynman diagrams) were more confusing than not. He did note that it took his graduate student three years to grasp them which was somewhat comforting. Nonetheless, toward the end they reminded me more of Abbott and Costello's famous skit we know as "Who's on first?" then the interaction of fundamental particles. However, Feynman's humor and witty style kept me reading for such jewels as "I have delighted in showing you that the price of gaining such an accurate theory has been the erosion of our common sense."

Nonetheless, as I lay this book to rest on my shelf I will admit that it does contain numerous dog-eared pages and lots of highlighting. I'm fascinated by the fact that some particles at the quantum level go backward in time. I mean, seriously, how cool is that? I now understand that QED is about the mysterious interaction between photons and electrons, which of course makes sense with a title of "quantum electrodynamics." Duh. I now also understand more fully what a Feynman diagram comprises. Thus, even though he was correct in assuming that I wouldn't understand it, I do know more than I did when I started reading so the experience was not a total loss.

One thing to bear in mind if you should decide to take on this book is that since 1983 when these lectures were delivered (and just happens to be the year I started college) much more has been discovered in the field of particle physics. This is explained beautifully by the proofreading notes at the end of this book, the first dated November 1984 which states, "Since these lectures were given, suspicious events observed in experiments made it appear possible that some other particle or phenomenon, new and unexpected (and therefore not mentioned in these lectures), may soon be discovered." The second proofreading note dated April 1985 stated, "At this moment the "suspicious events" mentioned above appear to be a false alarm. The situation no doubt will have changed again by the time you read this book. Things change faster in physics than in the book publishing business."

Probably the biggest news in this field to come in the past few years was the discovery of the "God particle" or Higgs boson. This book certainly prepares you for the existence of new particles and provides some understanding of what is involved in that process and why it's not an easy matter. It you really want to get into this stuff this book is a good primer.

In conclusion, it's worth noting that "Q.E.D." is a term also used in mathematics at the end of a proof as an abbreviation for the Latin saying "quod erat demonstrandum," i.e., "which was to be demonstrated." If nothing else, Feynman truly demonstrated that this stuff really is beyond human understanding even for those who can do the math. In other words, they may be able to determine what is going on but certainly not the why, which lies in another realm. Thus, it is my sincerest hope that since this great man now resides in that very place that he can at last fully understand it. I sure don't.

Richard Feynman is a legend. How can someone explain something that complex in such an easy language.

I had encountered with quantum physics several times in previous books and every writer talking about how hard it is, and it turned out that they are absolutely right. I know that because I read the book very slowly and later on I even skipped some parts of the book.

Nature is simple and very perplexing at the same time; And as Feynman said "You see my physics students don't understand it... That is because I don't understand it". LOL

In the beginning of QED, Richard Feynman says that people are always asking physicists about the new findings of a grand unified theory. He feels they should also be asked about known and confirmed theories instead of undercooked and partially analyzed ones. So he decides to speak about the “well dissected and marvelous” theory of QED. The theory describes the interactions between photos and electrons, space-time and probabilities, among others.

The book is based on four conferences given by Richard Feynman in the 1980s. These were done in memory of a friend of his who had passed away, Alix Mautner. She had a career in english literature but was curious about physics and often asked him about quantum mechanics. He never had the chance to explain her the theory of quantum electrodynamics (QED), for which he was awarded a Nobel prize (alongside Schwinger and Tomonoga), and which he described as “the jewel of physics”.

It’s remarkable how much content there is in this book, having only 150 pages or so. The explanations are easy, illustrated with a great amount of examples and figures, and may seem too simple at times, until Feynman shows the grand picture and demonstrates how brilliant physics is. He had the ability to make topics which could be seen as too complex become accessible.

I was delighted to read this book, as there aren’t many books for non-physicists that mention QED. Feynman’s mix of humour and humility just improves the experience.

This is a wonderful book and one couldn’t ask for a better teacher than Feynman. He reminds us that physics can be fun and inspiring.

Ce livre propose de vulgariser la théorie scientifique la plus exacte dont nous disposons avec laquelle il est possible de modéliser la lumière, la matière et leurs interactions réciproques, à savoir la mécanique quantique. Développée au cours du siècle précédent, elle se fonde sur des principes qui brusquent le sens commun, comme la dualité onde-corpuscule ou le principe de superposition, car il n'est plus possible de s'aider d'analogies à partir de notre expérience pour en rendre compte sans prendre le risque de commettre des erreurs, et seul la maîtrise de l'outil mathématique en rend compte fidèlement. C'est donc une gageure que d'expliquer ces mécanismes avec l'aide de petits schémas et dessins, tels que l'entreprend l'auteur.

Il s'y emploie cependant, illustrant par exemple des phénomènes aussi familiers que la réflexion de la lumière dans un miroir, sa réfraction dans l'eau ou le verre, ou encore le fait qu'une partie est transmise et une autre réfléchie. On aborde également la cause des magnifiques irisations diaprées qui ornent la surface des bulles de savons, les ailes des papillons ou la face lisibles des compact-disc. Tout est ramené au calcul d'une somme de probabilités représentée ingénieusement par de petites flèches mises bout-à-bout. Pour autant, je ne suis pas certain qu'il parvienne à rendre tout aussi clair qu'il le souhaite. La durée nécessairement limitée des exposés dont ces textes sont la transcriptions ne permettent pas d'en éclairer toutes les subtilités.

L'humour et la modestie avec laquelle l'auteur traite le sujet rend la lecture agréable, mais il me semble qu'en dépit des immenses efforts déployés par l'auteur pour rendre son sujet accessible, l'essentiel restera obscur pour le plus grand nombre, à moins de nourrir un intérêt particulièrement fort pour le sujet. J'ai néanmoins beaucoup apprécié que ce livre aiguise ma curiosité, et exerce mon émerveillement pour la beauté de la Nature.

If you are intrigued but intimidated by physics, this is a book for you. I truly believe the author purely wanted to share his knowledge about a subject he is passionate about, in the easiest way possible. Unlike some, he is not trying to scare people off using language only physicians would understand. He wanted people to understand what he understands - which must have felt impossible at times.

I particularly enjoyed the layout of this book. As someone with little knowledge of physics, it made it a lot easier to learn about QED through clearly structured “lectures” (and I would be very lost without the diagrams).

The tone makes it very clear that despite his remarkable accomplishments and successes as a physicist, he remains grounded by the world of science. Throughout the book, he reminds you that ultimately, nature is the greatest thing, and regardless of how much we think we know - there will always be more. The more questions we answer - the more questions we will have, infinitely.

“I hope you can accept nature as She is - absurd.”

أربعة محاضرات ألقاها فينمان في نيوزيلاندا قصد إيصال مفاهيم الكهروديناميكا الكمية لغير المختصين. و قد تمت طباعة هذه المحاضرات كهدية لروح "أليكس ماوتنر" التي كانت متيمة بالنظرية الكمية و التي كانت تطلب منه تفسيرها لها لكن القدر شاء أن ترحل قبل أن ينفذ طلبها. ينطلق فينمان من التساؤل عن ظاهرة الإنعكاس الجزئي ليتناول في المحاضرة الثانية الطبيعة الإحتمالية لحركات الإلكترونات و علاقة ذلك بالإنعكاس ثم ليتعمق أكثر في الفكرة و يشرح طريقة تفاعل الفوتونات مع الكترونات المادة و ما يتبع ذلك من خصائص هذه النظرية التي كان أحد روادها النظريين (نال جائزة نوبل رفقة جوليان شفينجر وسين توموناجا بسبب إسهاماته فيها).



و في حال لم تجعلك المفاهيم الموجودة في المحاضرة الثالثة أو ما سبقها (أقول ذلك و أنا المتعودة على ميكانيكا الكم) تعدل جلستك أكثر من مرة و تحدق في الفراغ مشدوها من سحر ما قرأت، فإن المحاضرة الرابعة بكل تأكيد لا تخلو من المتعة المعرفية ففيها بالإضافة إلى نقائص الكهروديناميكا الكمية حتى لحظة إلقاء المحاضرت، مقدمة رائعة سهلة و بسيطة لمجال أراه و يراه الكثيرون مثلي الأكثر تعقيدا في الفيزياء الحديثة و الحديث هنا عن فيزياء الجزئيات.



يبهرني فينمان مرة أخرى بقدرته الكبيرة على إيصال المفاهيم الفيزيائية دون العودة إلى الرياضيات ما خلا بعض الأمثلة الضرورية و التي لا تتطلب الكثير من المعرفة الرياضية. طبعا أي شخص درس الفيزياء في عالمنا العربي سيعرف أن الإنطلاق غالبا يكون من القاعدة الرياضية للتفسير...شخصيا لا يمكن أن أجد تفسيرا غير كون الأستاذ غير ملم بالمفهوم أصلا و أن واضع المنهج لا يهدف إلى خلق جيل مفكر و أن محاضراتنا الجامعية في غالبها جوفاء تخلو من العمق المعرفي...خمس نجمات و أرغب حقا في إضافة سادسة لو كان ذلك ممكنا ...إلى لقاء آخر سيد فينمان





14/09/2020

Kada bi imali sreće da u toku školovanja imamo više ovakvih predavača... Neverovatno je kako je Fajnman uspeo da objasni ove teorije čak i laiku poput mene.

I first read Ottaviani's biographical comic of Richard P. Feynman and that is how I got interested in quantum electrodynamics. I'm not really good when it comes to physics (I do love math), but light and lenses I have understood and enjoyed always. Thus getting my hands on this book was wonderful!

Feynman explains quantum electrodynamics very clearly with a humorous twist. The book is logical and very well written altogether. The last chapter is the only somewhat hard part, since in that one Feynman tries to explain other fields of physics and how they interact with quantum electrodynamics. What makes it hard is that the chapter is short and just a peek. Feynman makes me believe that quantum electrodynamics is easy, but it tells more about Feynman's marvelousness than me. As a whole the book was amazing and I'm happy to have understood almost all - and let's face it, it's physics!

Actually this book should be ranked six stars or more. I have never read anything as inspiring and interesting as QED before.