Read QED: The Strange Theory of Light and Matter by Richard Feynman Online


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. MautnFamous 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....

Title : QED: The Strange Theory of Light and Matter
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ISBN : 9780691024172
Format Type : Paperback
Number of Pages : 158 Pages
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QED: The Strange Theory of Light and Matter Reviews

  • Manny
    2018-11-20 03:37

    Sometimes, it's too late, but that makes you do it better. You probably imagine that this book is a physics text. Well, it is, but that that's not what it really is. Really, it's a love letter to a dead woman. Feynman says in his introduction that his friend Alix Mautner had always wanted him to explain quantum electrodynamics to her so that she could understand it, and he'd never gotten around to doing that. Now it was too late. But, somehow, you can see that that only made him want to do it, not just well (he did everything well), but perfectly. If the book was perfect, that would make up for its appearing after Alix was no longer around to read it. It may seem like an odd formula, but it worked for Dante, and it also worked for Feynman.The rest of this review is available elsewhere (the location cannot be given for Goodreads policy reasons)

  • Roy Lotz
    2018-11-04 04:21

    I love this area of physics and I think it’s wonderful: it is called quantum electrodynamics, or QED for short.I love this book and I think it’s wonderful: it is called QED: The Strange Theory of Light and Matter, or QED for short. I feel as though I’ve been searching for this book for a long time, and now I’ve finally found it. In scarcely 150 pages, Feynman takes you inside the logic of this famously obscure subject. What was before unintelligible is breezy in Feynman’s hands. What had before seemed impossible and bizarre of the physical world—particles behaving like waves, going back in time, eluding measurement—is, in Feynman’s presentation, just Nature being goofy.So here’s the mystery. Newton proposed, in his Opticks, that light is corpuscular, or comes in little packets like raindrops. But it was later observed that light can interfere with itself, so it must be a wave. (For a while, English physicists were loath to admit that Newton could be wrong.) Then experimenters ran into trouble again when they discovered that if you take an extremely dim light and aim it at a detector, you don’t get one continuous signal, but a series of beeps and pauses like Morse code. So it appears that light comes in packets after all. But wait! In certain circumstances, if you shoot these particles one-by-one, you get an interference pattern like a wave. So light was both a particle and a wave? How was that possible?Feynman begins by saying that this question—How is this possible?—isn’t the right one to ask. Physics is an experimental science, so its task is to come up with a theory that will make predictions that agree with experiments, not to resolve philosophical paradoxes. In this book, that’s just what he does: he explains what physicists are doing when they are making these predictions. To do this, he must delve into the math. But he does not wish to explain how his graduate students do it (which wouldn’t be feasible in a book of this size, anyway), but to explain what is going on behind the scenes when they do these calculations. It’s like teaching children to add with pebbles rather than on paper.Feynman begins by telling us that, in quantum physics, we calculate probabilities, not certainties. That’s a bit disappointing, but that’s the way nature is. So when a physicist is calculating the probability that a photon will pass through or reflect off a pane of glass, they use “probability amplitudes,” which can sometimes reinforce and sometimes cancel one another. With this method, we can predict how many photons out of 100 will reflect, and how many will pass through. Not only that, but we can also deduce the wavelike properties of photons interacting with electrons to astounding levels of accuracy—so accurate that if you were measuring the distance from New York to Los Angeles, the uncertainty would be equivalent to the width of a hair. So as far as scientific theories go, QED is pretty dang good. But what are “probability amplitudes” in reality? It seems a bit cheap at first, like Feynman merely found a clever way to talk about particles as waves without having to use the word “wave.” Feynman describes how to calculate the answer by picturing the particle as having a little clock hand that spins extremely fast, giving you an angle. In the end, two arrows (the amplitudes) are added up, the result is squared, and there’s your answer—a percentage. But what is really going on down there when the photon is traveling from the light source to the detector? What is happening before our measurements? Surely, there are no clock-hands attached to the particles. What's the mechanism behind all this?Of course, this is the kind of questioning that Feynman discourages. In his words:So this framework of amplitudes has no experimental doubt about it: you can have all the philosophical worries you want as to what the amplitudes mean (if, indeed, they mean anything at all), but because physics is an experimental science and the framework agrees with experiment, it’s good enough for us so far.So, really, there’s no way of knowing what’s going on before the particle is detected, since it is, in principle, undetectable. And in science, only things that can be measured are real. All of the stuff used to obtain the answer is just an intellectual apparatus, a tool for calculation.Yet it’s hard to be as content with this as Feynman. If you wanted to learn how a car works, you’d want to know what’s going on in the engine, the transmission, the steering and braking. If somebody told you, “It works by turning the key and stepping on the gas,” you’d feel like you were cheated. But this is what we must do in QED. Nature doesn’t allow us to look under the hood. We can step on the gas and the thing moves; we can come up with an equation that helps us predict how fast the car will go depending on how much we press on the pedal. But what makes it go? Who knows? As Feynman said: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.

  • Tara
    2018-11-20 06:43

    My reaction upon finishing this book:(Any excuse for a Breaking Bad reference.)Seriously, though, this is one of the best pop science books I’ve yet encountered. I read Surely You're Joking, Mr. Feynman!: Adventures of a Curious Character last year, and was thoroughly impressed by Feynman’s animated personality and his passion for physics. Now I find myself even more impressed by his exceptional teaching ability. QED: The Strange Theory of Light and Matter is a collection of 4 lectures he gave to the general public on the subject of quantum electrodynamics. The book is intended for laypeople, is written in very accessible language, and provides “Feynman diagrams” instead of advanced mathematical formulae. A rather lengthy summary of these fascinating lectures follows. If you don’t want any spoilers, or whatever you want to call them, then skip ahead to the final paragraph.The first lecture deals with photons, and how light behaves like particles. This is discussed in detail w.r.t. the partial reflection of monochrome light by glass. There’s already some fascinating shit right here, let me tell you! See, physicists can’t predict which photons will get reflected and which will pass through the glass. All they can tell you is the overall probability that it will happen. In other words, “identical photons are always coming down in the same direction to the same piece of glass,” and this somehow winds up “producing different results” each time. Who knew that “partial reflection by a single surface” was a “deep mystery and a difficult problem”?! Bizarre.Feynman then teaches us how to calculate the probability of photons bouncing off either the front or the back surface of sheets of glass of varying thickness. The lecture concludes with a discussion of iridescence (the colors produced by the reflection of white light by two surfaces). Neat-o.In the second lecture, Feynman uses QED to explain why, when light reflects off a mirror, the angle of incidence is equal to the angle of reflection. This is weirder than you might assume. (Actually, “weirder than you’d assume” sums up the entire book remarkably well!) The phenomenon discussed here is also the basis for diffraction gratings. Then he covers how light travels from air into water, and what causes mirages. Feynman goes on to explain why light appears to travel in straight lines. Incredibly, it behaves as such only when you give it enough wiggle room, so to speak. For “when you try to squeeze light [or restrict its path] too much to make sure it’s going in only a straight line, it refuses to cooperate and begins to spread out.” This is not altogether dissimilar to the behavior of surly teenagers. Perhaps we can reasonably refer to them as “little rays of sunshine” in an unironic fashion from now on! :D Bad joke, sorry. Anyway, the manner in which focusing lenses work is next revealed, and the lecture concludes with how quantum theory calculates the probability of compound events.The third lecture introduces electrons, which behave similarly to photons: somewhat like waves, somewhat like particles. (Feynman jokes about “wavicles,” a term I actually love to death, and will enthusiastically champion from now on!) We learn of the three basic actions from which all the phenomena of light and electrons arise: 1) photons rollicking about, 2) electrons rollicking about, and 3) electrons emitting or absorbing photons. As per the first item, we learn that “light doesn’t go only at the speed of light.” So yeah, that happens. It’s anarchy, I tell you! Madness! And the third action is even stranger. Hint: time travel may or may not be involved. Oh, you beautiful, depraved little positrons, you.Next, Feynman covers how electrons behave in atoms. He re-examines the partial reflection of light from glass in far greater detail than he did earlier, and we can now see why the former simplification was in fact warranted. (We previously treated light as reflecting from the “front” and ”back” surfaces of a sheet of glass, as opposed to what light actually does, which is to be scattered by the electrons inside the glass.) This scattering is also the reason light appears to move more slowly in glass or water than it does in a vacuum or in air. Also of interest is how lasers work: photons tend to go to the same point in space-time. (These lunatics are predisposed to travel in packs!) It turns out the reverse is true for electrons. Their aversion to one another is known as the “Exclusion Principle,” and helps explain chemical properties of atoms. Before finishing the lecture by discussing polarization, Feynman examines the complexity of the magnetic moments of electrons. This is fairly bananas, even considering the fact that the entire book is pretty much out to lunch. Here is what can happen: an “electron goes along for a while and suddenly emits a photon; then (horrors!) it absorbs its own photon. Perhaps there’s something ‘immoral’ about that, but the electron does it!” (You really have to love his sense of humor.) I’ve included some Feynman diagrams which depict this wanton immorality:The fourth and final lecture deals with some problems associated with quantum theory. It also looks at the relation of QED to the rest of physics, and includes a discussion of fundamental particles such as quarks and gluons, to name but a couple.Overall, this short book is packed full of mind-blowing information. I really appreciated all of the helpful diagrams that illustrate the very peculiar concepts under discussion. Also, Feynman is an excellent teacher. I just loved his occasional bursts of exuberance and humor. His enthusiasm for his subject is irresistible, his subject itself truly extraordinary.

  • Matt
    2018-11-21 08:37

    I took this photo when I was about half way through the book. It shows a picture of a CD [click to enlarge]. It's been illuminated by an ordinary office lamp and the flashlight from my camera. I knew about this "rainbow" effect for a long time, but I didn't know exactly how it is created. This book gives some answers.To write a successful book like QED (short for Quantum Electro-Dynamics) two prerequisites are required: 1) The author must know a great deal about the subject matter, and 2) He must love his work. Only then it is possible to explain the theory of QED to laypersons like me. Richard Feynman obviously fulfilled both of these conditions. For one he virtually "invented" Quantum Electro-Dynamics (and received the Nobel Prize for physics for it in 1940) and secondly you can clearly sense his deep affection for the nature of objects and processes in the realm of the very very very small things, that is the quantum world.Instead of bothering the reader with mathematical formulas like this......Feynman developed a rather ingenious way of explaining the interaction of light particles (photons) and electrons (and later other particles too) using diagrams like this:All those little arrows are of the utmost importance because they represent what is called "probability amplitudes" for an event. The longer the arrow the more likely the event. In fact all we have to do–in theory–is to draw all possible little arrows on a piece of paper to explain almost any phenomenon concerning light that we can observe in nature. Don't ask me why that is. In fact even Richard Feynman couldn't answer the "why", only the "how". That's the charming thing about quantum theory. It has to be pointed out that this way of dealing with quantum effects is not a deviation from the truth (as far as anyone knows the truth). Other popular science books make things too easy and thereby achieve simplicity only for the price of a somewhat distorted truth. Not so here!But don't think that this drawing of arrows (and then later in the book what is called the "Feynman diagrams") is very simple. There are quite some things to consider, and the text is pretty dense. Anthony Zee, a Chinese American physicist, wrote in his introduction to QED:[...] you must mull over each sentence carefully and try hard to understand what Feynman is saying before moving on. Otherwise, I guarantee that you will be hopelessly lost. It is the physics that is bizarre, not the presentation.I have to agree to that. Whenever I came to a point where Feynman lost me I skipped back a few pages and read it again....and again, until I made sense of it (as much sense as was possible for me). I think I understood the majority of this book, I just haven't internalized it. Not yet anyway. Maybe I have to read the whole book again after a couple of weeks. Until then I keep a quantum of solace that we (the humankind) are by now advanced enough to understand what make these cool "rainbow things" on CDs.I highly recommend this book to anyone interested in the very foundation of what makes the world work the way it does.This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

  • AnnMarie
    2018-11-05 08:22

    You could call me a science groupie. I put on Cosmos while I clean the house, snatch up Michio Kaku's books like they won't be there tomorrow, know all the words to every Symphony of Science song ever, and follow Neil deGrasse Tyson on Twitter--but that doesn't mean I know the first thing about real science. I couldn't solve a linear algebraic equation even if the world depended on it (sorry, world). Instead, I revere famous physicists from afar while most women my age drool over movie stars like What's-His-Face. You know the one. That really hott one.Anyway. Richard Feynman is definitely in the top five on my list of favorite physicists. (Yep, I have a list. Expect nothing less from a girl who named her cat Sagan.) I love Feynman's sense of humor and his whimsical world-view. He may be gone, but he's not forgotten. So when I had a stupid question about light, I figured it was high time I read his book on the subject. My stupid question goes like this: Why is it that, when you turn off a light, the room immediately goes dark? Where does the light go? Why doesn't it bounce around the room for a bit before dispersing? If light is everywhere, why is the universe so dark?Well, this book didn't really help me answer those questions. If Feynman taught me anything here, it's that light is the honey badger of particles: it does what it wants, and leaves tiny arrows in its wake. Or something. I'm not sure.

  • Paul
    2018-11-11 01:22

    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.

  • Edward
    2018-11-17 09:49

    QED: The Strange Theory of Light and Matter is an outstanding book on a subject that is often overlooked or glossed-over in many popular physics books. Feynman does a deep dive on Quantum Electrodynamics: a theory that deals not only with the various interactions between light and matter, but which can be applied to every area of physics with the exception of gravitation and nuclear physics.The theory of QED is fascinating, both in its explanatory power and its elegance. Using only a handful of conceptual tools, and working with just two fundamental particles - the photon and electron - it can describe phenomena as varied as reflection and refraction of light, changes in the speed of light through different mediums, quantum interference, lenses (I found the application of QED to this seemingly mundane property of glass to be particularly mind-blowing), and even suggests how all the diverse properties of the elements arise from only three basic actions performed by these two fundamental particles. To say that this book changed the way I see the world is only a slight overstatement - it has certainly opened my eyes. QED is an absolute must-read for anyone with an interest in physics. Feynman takes great pains to present the theory in a clear and logical way, and while the subject is challenging, it is utterly comprehensible from cover to cover. This is by far the best popular science book I've read in a long time - I cannot recommend it highly enough.

  • Yann
    2018-11-01 08:21

    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.

  • Jose Moa
    2018-10-31 05:33

    Wonderful,Feynman is a genius of popularization,without a mathematical expression has achieved the goal of give the rigurous quantum electrodinamics fundaments of geometric and physical optics,is to say,refraction,refraction index,reflexion, difraction ,converging lenses,classic Fermats principle of minimun time in path light and so on.He uses arrows to represent complex numbers in complex plane,with its modules and phases and uses sums and products of histories in the propagation of the photon as sums and products of this arrows to obtain the final amplitude.Also he explains the bizarre and incomprehensible behavior of the photon as it explores all ways each one with it own phase and in the sum the major contribution is of similar to classical path of mínimum time.Also the strange property of a photon or electron that in the doublé slit experiment is able of have interference with itself.In the next chapter,explains his diagrams,how to calculate each piece,the propagation piece and the vertex piece,also the radiative serie of corrections,succesful in explanation of the magnetic moment of the electron and also with a diagram explains very well as a positrón can be viewed as a electron going backwards in time.In the last chapter explains the only ugly aspect of the theory,the problem of the infinities and the renormalization solution,ends with a brief account of the standard model.He also makes a deep reflection in the sense that the complex amplitudes has no physical meaning and that the deep work of the theory is incomprehensible,the idea is that we dont know the true working of reality,only knows the model we make,the reality has a behavior as the model predicts but no more,our model is a simulation of reality and we only can know that simulation.A masterpiece of science popularization,strongly recomended to those that want to have a taste of the deep conceps and strangeness of the quantum world reality

  • Joshua Nomen-Mutatio
    2018-11-03 07:50

    It's all arrows, man. All about arrows. Physics is not a subject I have a terribly good grasp on mainly because my eyes glaze over at the sight of advanced mathematical equations, however Feynman is a pretty great at making the complex subjects of particle physics and quantum mechanics intelligible to the layest of laypersons. Fortunately I also read this with able-minded people who translated the math into clearer ideas which of course opened things up to broader philosophical speculation--something I am pretty good with. The introduction to the book is also worth reading by itself at the very least."I think I can safely say that nobody understands quantum mechanics."-Richard FeynmanHe was also a very funny and clever man who left behind a whole host of aphoristic gems, for instance: "A poet once said, 'The whole universe is in a glass of wine.' We will probably never know in what sense he meant it, for poets do not write to be understood. But it is true that if we look at a glass of wine closely enough we see the entire universe. There are the things of physics: the twisting liquid which evaporates depending on the wind and weather, the reflection in the glass; and our imagination adds atoms. The glass is a distillation of the earth's rocks, and in its composition we see the secrets of the universe's age, and the evolution of stars. What strange array of chemicals are in the wine? How did they come to be? There are the ferments, the enzymes, the substrates, and the products. There in wine is found the great generalization; all life is fermentation. Nobody can discover the chemistry of wine without discovering, as did Louis Pasteur, the cause of much disease. How vivid is the claret, pressing its existence into the consciousness that watches it! If our small minds, for some convenience, divide this glass of wine, this universe, into parts -- physics, biology, geology, astronomy, psychology, and so on -- remember that nature does not know it! So let us put it all back together, not forgetting ultimately what it is for. Let it give us one more final pleasure; drink it and forget it all!"

  • Jimmy Ele
    2018-10-30 09:31

    The particle view of physics and how Richard Feynman was able to explain all of the weird ways that light behaves was a thoroughly engrossing read. The intellectual feat that was performed by this man in creating a workable mathematics for the physics behind the way that light travels, and reflects is truly amazing. Using the simple concepts of rotation, spin, frequency, and depicting it all with some simple calculations involving arrows and simple algebra gave me a sense of awe at the simplicity of such a seemingly complicated subject. Even though I currently side with the field theory of Julian Schwinger, I must say that I can not blame anyone for using Q.E.D. as the model for their calculations. Overall, I had to place this on my foundation list, seeing as it gives me inspiration for explaining the seemingly complicated in very simple terms that can be easily understood by many.

  • Sebastian
    2018-11-13 01:35

    Throughout the years of reading both popular and less-popular science, I’ve kind of steered clear of Richard Feynman. The main reason is that what others describe as a “larger than life persona” I tend to describe as really bloody annoying, what with his bongos and womanizing and oh-so-clever quips where he always gets the upper hand with the old and rusty physics establishment. Having now fought my way through QED, I can see that this may have been a mistake. My annoyance with his autobiographical works has kept me away from some truly gorgeous scientific writing.The thing is, I’m not sure if it is even possible to explain quantum mechanics properly without all the higher math, but if it is possible, this is likely the only proper way – with a lot of “this is how it is, and don’t ask why, because even we, physicists, do not know”, and a lot of weird and unexpected analogies, such as his substitution of “little clock hands” for the harmonic oscillator that pops up every which way in QM. The only problem I had was that knowing the “proper” theory it took me a while to fully intuitively accept and adopt his “tiny clocks running” description and match it with the complex numbers/oscillators he is describing in this roundabout fashion. However, once that clicked into place, his descriptions of simple everyday phenomena, such as reflection and diffraction, the two-slit experiment, and later on the interaction of electrons and photons, really popped off of the page and sort of “broadened the groove” wherein all the counter-intuitiveness of QM is trying to get a foothold in my brain.

  • Bob Nichols
    2018-11-07 05:21

    In this series of short lectures, Feynman reduces (except for gravity and radioactivity) the whole of the universe to quantum electrodynamics or QED.* QED involves the relationship between photons (light) and electrons (matter), or quantum phenomena, the interaction of which (electrons emit/give up and absorb/get photons/particles of light) creates all of the atoms and elements in the universe. Feynman uses light’s refraction to illustrate the relationship between electrons and photons. To understand light, one has to lose “common sense,” he says. Light does strange things. We understand light not as specifically identified photon movement but in terms of probability. “I am not going to explain how the photons actually ‘decide’ whether to bounce back or go through [an opening]; that is not known,” he writes, and then adds, “(Probably the question has no meaning.)” Light seeks the fastest (shortest) route in its movement from A to B, but it borrows or uses paths that are adjacent. When light moves through a small opening, it also spreads out. In this regard, he writes that “light doesn’t really travel only in a straight line; it ‘smells’ the neighboring paths around it and uses a small core of nearby space.”Electron movement is strange as well. Electrons jump from one path to another and positive electrons (positrons) go backward in time. The book quickly gets technical. It is filled with Feynman diagrams and I can’t say I grasped much. Feynman is describing quantum phenomena but describing is different than understanding. “While I am describing to you how Nature works,” he writes, “you won’t understand why Nature works that way.” “My physics students don’t understand it….That is because I don’t understand it. Nobody does.” This makes his quote above, “Probably the question has no meaning,” particularly interesting as Feynman seems to be saying that, in the end, we can only describe how nature works, but not why it works the way it does. By extension, is Feynman saying that there are no ultimate explanations (e.g., God, Deist design) for the cosmos and how it operates, and that Nature just Is?*“The theory describes all the phenomena of the physical world except the gravitational effect, the thing that holds you in your seats,..and radioactive phenomena.” QED is “a horrible name,” Feynman concedes. The theory also describes what goes on inside the nucleus itself, which are the quarks and gluons, and involve some 400 (and counting) subparticles.

  • Lee
    2018-10-28 08:39

    This weekend just passed my flatmate's boyfriend was visiting. Being the inquisitive sort, at one point he asked me if I could explain the main results of my PhD thesis to him in terms he would understand. To my eternal shame my knee-jerk response was "No." But a few moments later I was to be found scrawling on a napkin, explaining rational points on curves, density arguments, counting functions, and concluding by using the word "generalise" far more times in one sentence than I was comfortable with.He seemed to follow my haphazard ramblings which is always enough to leave one chuffed. It's no secret to the science community that its biggest failing is an inability to communicate with and engage the public. The more esoteric the science, the trickier it is to convey it in terms that are both accurate and interesting. And, outside of pure mathematics, it doesn't get a great deal more esoteric than quantum mecahnics. So Richard Feynman's QED is laudable for, if nothing else, being about as understandable as is possible with this subject. There were times that the text lost me, but after giving it some thought I realised in each case that it was because I was expecting the quantum world to make sense, and to paraphrase my old Physics teacher: if quantum mechanics starts making sense, then you've stopped understanding it.Feynman's abilities as a scientific orator are pretty well known—one of my favourite videos on Youtube is a two-and-a-half minute video of Feynman sitting in a chair explaining how a train stays on the tracks. Seriously. Feynman's writing skills are apparently just as good, but I've not read any of his other books and this one is actually the edited transcriptions of four of his lectures, so his speaking prowess proves more useful here. And as if being fascinating, self-deprecating, and witty wasn't enough, he also manages to be quite touching. The lectures were the inaugural set in a series dedicated to Alix Mautner, an English major and long time friend of Feynman to whom the physicist had promised to explain quantum electrodynamics in terms she could understand. Sadly she died before he managed to do so, but the lectures here are, as he says, the ones he prepared for Alex, but that he could no longer give just to her.

  • Fraser Kinnear
    2018-11-12 01:40

    I think this is my favorite science book. This was in large part due to having Feynman's real voice in my head, as I've heard him often in recorded lectures and documentaries.The book is transcription of a few lectures Feynman gave on Quantum Electrodynamics (QED), a branch of quantum theory he and Dirac developed. Feynman introduces a few simple rules on how electrons and photons behave (which appear to be easy-to-digest analogs for vector calculus) and then off he goes, explaining the theory and how it describes an enormous amount of phenomena, such as the uncertainty principle, the how lenses and mirages physically work, how light scattering creates particles that travel backwards in time (via an antiparticle), why electrons stay in their orbits, lasers (exclusion principle). The only concept which I felt didn't come across quite so clearly was his discussion of spin. Once he is satisfied with the level of detail he gave to explaining QED, Feynman quickly runs through the rest of the menagerie of sub atomic particles, doing little more than listing them and noting that the toolkit from QED is useful in describing the interaction of quarks and gluons.

  • Derek Daigle
    2018-11-07 08:25

    There hasn't been anybody in the history of mankind that has summed up such a complex subject as Quantum Electrodynamics with so much enthusiasm and eloquence as Feynman. You can hear his giddyness levels rise as if he were directly talking to you, and is nothing like a stale textbook simply stating facts. Quantum Physics would not be NEARLY as accessible as it is today if it weren't for this man. Einstein the prototype laid down the framework for Quantum Physics by accidentally dumping the puzzle pieces on the table, appalled with the mess he made... Feynman the archetype cleaned it up with unyielding excitement by flipping over all the pieces.The puzzle is still far from complete, but we would be nowhere without this book (and others like it).

  • Sookie
    2018-11-13 06:45

    Its a subject that got glazed over when I was in Engineering and after that, a wiki entry that I frequented whenever I had questions. Feynman targets this book to, well, everyone. He holds your hand and shows how things work. Its a slow step by step process and if you invest some time, its highly rewarding and quite refreshing to be taught physics by a man who is long dead but doesn't really feel so when you read his words. You get transposed to his classroom as he explains basic concepts and the paradox surrounding the most natural thing in this world: light.Its a re-read which I enjoyed and will get on to re-reading some of his other famous lectures.

  • Ami Iida
    2018-11-01 05:33

    、Chapter 3; electrons and their interaction will be a clue to solve all the phenomena for the universe.It's the absolutely essential reading physics book for everyone .

  • Remo
    2018-11-03 04:43

    Esta es una de las muchas incursiones que hizo el gran Feynman en el terreno de la divulgación científica. En realidad él no escribió ninguno de sus libros de divulgación científica, sino que se adaptaron de sus ciclos de conferencias de divulgación, que, ahí sí, Feynman preparaba a conciencia. Este libro surge de una serie de cuatro conferencias que dio Feynman en UCLA (que en inglés no se dice ucla sino u-c-l-a, iusielei, dato CPI para viajeros por tierras californianas).La electrodinámica cuántica, además de asustar con su nombre chulo y molón, es la parte de la física que se encarga de estudiar las interacciones entre la luz y la materia (o, más concretamente, entre los fotones y los electrones). Es, abreviando, la teoría del electromagnetismo pero en versión cuántica. La electrodinámica cuántica no entra en las reacciones nucleares o intra-nucleares. Feynman contribuyó decisivamente al desarrollo de esta teoría, motivo por el que recibió su premio Nobel de 1965.Feynman logra la hazaña de hacer algo más comprensible la mecánica cuántica a partir de unas pocas situaciones bastante simples. Cuando iluminamos un cristal de frente, dependiendo del grosor del cristal, se refleja más o menos luz, en valores que oscilan desde el 4% al 16%. El resto de la luz atraviesa el cristal (técnicamente un cristal es otra cosa y una ventana es un vidrio). Feynman reconstruye los mecanismos básicos de la teoría cuántica a partir de la explicación de este fenómeno. Después, otra pregunta simple. ¿Por qué la luz, al rebotar en un espejo, sale reflejada con el mismo ángulo con el que llegó? Esta simple pregunta sirve para plantear toda la teoría de integrales de caminos de Feynman, que explica un montón de fenómenos cotidianos. Cuando un electrón va de A a B rebotando en un espejo, según el modelo de la Electrodinámica cuántica, no sigue un camino sino muchos (de hecho, todos los posibles). Para cada camino hay asociada una probabilidad y una fase, concepto crucial que Feynman explica como un maestro que fue. La suma de todos los caminos nos da el camino más probable, que resulta ser, oh sorpresa, la reflexión clásica en la que el ángulo de entrada es igual al ángulo de salida. El rayo de luz rebotando en un espejo, base de la construcción de las integrales de caminos de Feynman. Finalmente, Feynman da el salto y nos habla de las interacciones entre partículas, de la cromodinámica cuántica y usa profusamente sus diagramas (los famosos diagramas de Feynman), utilizando bastantes conceptos expuestos en los dos primeros capítulos (las dos primeras charlas).Diagramas de Feynman. Aunque parezcan complicados Feynman los hace simples.El libro no es complicado en el sentido de que no tiene fórmulas ni desarrollos matemáticos. Feynman presupone una audiencia sin formación pero con capacidad de aprender y razonar. Comienza explicando cómo sumar dos flechas (vectores) y cómo sumar dos números (tiempos), y a partir de ahí tira para adelante. Sin embargo, tampoco es un libro de entretenimiento y pasar el rato. Hay conceptos que deben ser pensados un par de veces antes de seguir, y les recomiendo que no pasen a la siguiente cuestión sin entender la anterior. Al acabar, uno tiene la sensación de que bajo el capó de las charlas de Feynman hay un increíble y complicadísimo mundo, cosa que es cierta, pero que uno ha aprendido los rudimentos básicos del funcionamiento de la luz y la materia, cosa que también es cierta. Feynman era un gran divulgador, y lo demuestra.Mi nota: excepcional.

  • Maanasa
    2018-10-25 06:40

    When I first heard of the two recent quantum physics mega-events--the discovery of the Higgs-Boson particle and the confirmation of the Inflation theory--I knew that these were events of massive import but I was woefully ill-equipped to understand the "why" of it. What began as a wikipedia binge of particle physics terms and definitions, became an attempt to understand the four fundamental forces, which then led me to Richard Feynman's QED. This book attempts to explain to the layperson one of the fundamental forces of nature--electromagnetism--and to give us a glimpse into the ways that light and matter interact to give rise to a host of derivative (in the non-science/math sense of the term) phenomena like optics, heat transfer, electricity, magnetism, etc.While the book doesn't have the ability to make theoretical physicists out of us all, it does help the reader see the outline of the bigger picture (or should I say the infinitesimally tiny picture). I think one of Feynman's biggest successes as a translator come through his ability to 1) find the right metaphors, and 2) state clearly which ideas he is simplifying and which ones he is ignoring in order to make the material digestible. Feynman's tone is humorous and his language pithy. The diagrams used to illustrate concepts are extremely helpful. I, for one, am very glad to have gotten a glimpse into this fundamental concept that governs the world that we live in through this well-presented and fun book.For those of you only interested in my view on the book, you can stop reading here. From this point on, I digress a little.I have often heard people brandish the line "a little knowledge is a dangerous thing." The origin of this line can be traced back to Alexander Pope's poem, "Essay on Criticism," and is often spouted to support the proposition that one must abstain from learning unless they mean to go all the way. However, I have always found this to be an incredibly superficial (totally ironic, I know) reading of the line given the context in which it appears. The poem states: "A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring (spring of inspiration and knowledge - from Greek mythology): There shallow draughts intoxicate the brain, And drinking largely sobers us again."Within this context, it's clear that Pope isn't trying to tell us that spotting the tip of an iceberg itself is dangerous, but that spotting the tip without realizing that there is more to the iceberg than its tip is what is dangerous. I strongly believe that as long as a person is aware of how incomplete or superficial his/her learning is, s/he can steer clear of said "danger". It is not only OK, but recommended that we try to broaden the scope of our intellectual pursuits even if we do not have the necessary resources to deepen them. And this book perfectly furthers that goal.

  • Mary-Jean Harris
    2018-11-06 06:49

    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.

  • Martin
    2018-11-09 08:24

    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.

  • Duncan
    2018-11-04 09:43

    QED is a book about quantum electrodynamics, which may sound complex, but with Richard Feynman teaching, its much easier to learn. This book covers basically what quantum electrodynamics is--the interaction of light with charged particles. However instead of advanced mathematics and complex words, Feynman uses the famous Feynman diagrams and other visualizations to explain things. This is a great read for anyone interested in physics, and if you fall into that category, you should read other Feynman books and lectures.If Feynman taught every physics class in the world it would be considered as easy as addition and subtraction. He manages to explain things that sometimes can take a whole semester of a college class in one short 175 page book. Anything from quantum electrodynamics and photons to basic physics equations is simple to learn with him teaching. Not to say its all easy, it does require some serious foreknowledge of the subject matter to read this book. The most amazing thing of all is this book doesn't even contain one equation, because Feynman explains everything so well it is unnecessary for the reader.

  • Shawn
    2018-10-31 04:42

    My biggest mistake here was reading this in small bursts. It was helpful to have things framed in layman's terms, but I still found myself not "getting it" at times, and I think that was probably because I was only reading it in short bursts and then not taking time to make sure I went back and really understood before forging onward. I did gain new insights and understanding into many details that were unknown to me about quantum electrodynamics, including some exposure to things like gluons, mesons, quarks, and such which I've heard of, but never really had much understanding of before. I think the reviews are high for this because the people likely to read this are physics majors and technical types--I think a broader sampling of non-technical readers would likely result in lower reviews because many people would still find it incomprehensible, despite Feynman's talent for making complex stuff understandable. If you are on the fence about reading this, consider browsing the Wikipedia entry on quantum electrodynamics which has a short section on "Feynman's view of quantum electrodynamics." It gives a short idea of what one will find in the book.

  • Siina
    2018-11-21 06:33

    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!

  • Dean Hamp
    2018-10-27 04:35

    I visited my brother a long time ago, when he was working on his Ph.D. in Physics. He tossed a small, innocuous-looking book to me and said, "Read this - its a complete brain-f**k. I've been hooked ever since. QED is, by far, the best piece of non-fiction I have ever read. It takes a long time for me to work though the concepts, and, as Feynman points out, nobody (including me) (especially me) truly understands Quantum Electrodynamics. But to begin with adding 'damned little arrows' and take that to an all-encompassing description of atomic theory, accurate to ten decimal places, in about 120 pages, so the likes of me can follow along, is the purest of genius. Bravo!

  • Squatting Erudite
    2018-10-30 07:35

    A masterpiece of popular science. Feynman did what most authors can only dream of... He explained extremely difficult concepts from his path integral formulation of quantum mechanics and he even made renormalization sound intuitive... and he did it all without any equations, but without hand-waving.I feel like I really understood something... maybe that's because I'm a physicist and I know some of these things, but nevertheless I think Feynman explained everything so clearly that a layman could understand it without any difficulties.That's what a good popular science book should be like. Highly recommended, obviously. Don't you want to understand how our world works?

  • Mishehu
    2018-11-06 02:46

    As a product of its time, I'd rate this a terrific effort. And, of course, it's always a delight to spend time in the company of Richard Feynman, even if only as a reader. Judged against the many exceptional popular science books that have been published since, however, this one suffers in comparison. The subject matter is fascinating, the explication only so successful. The book is well worth reading, though, a) because its author was such a talented scientist and such a cool dude, b) because the author was himself a major contributor to the branch of physics it describes, and c) because the tack he takes is an unusual one for popular science treatments (and quite interesting).

  • فےـيےـصِےـل | Faisal
    2018-10-25 09:21

    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

  • Jiri Bednar
    2018-10-22 06:39

    This book gives you a great insight on how our universe works (sans gravity). It doesn't give you the maths required to calculate the actual probabilities, but it does give you a framework to understand the math if you decide to learn it (for example from Feynman's Lectures)