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The Famous Feynman Lectures on Physics: The New Online Edition (in HTML5)

in e-books, Physics | September 14th, 2013 Leave a Comment

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Caltech and The Feynman Lectures Website are pleased to present this online edition of The Feynman Lectures on Physics. Now, anyone with internet access and a web browser can enjoy reading a high-quality up-to-date copy of Feynman's legendary lectures. This edition has been designed for ease of reading on devices of any size or shape; text, figures and equations can all be zoomed without degradation.1

Caltech and The Feynman Lectures Website have joined forces to create an online edition of Richard Feynman’s famous lectures on physics. First presented in the early 1960s as part of a two-year introductory physics course given at Caltech, the lectures were eventually turned into a book that became a classic reference work for physics students, teachers and researchers. You can still purchase the 560 page book online, or enjoy a new web edition for free.

Created with HTML5, the new site gives readers access to “a high-quality up-to-date copy” of Feynman’s lectures.” The text “has been designed for ease of reading on devices of any size or shape,” and you can zoom into text, figures and equations without degradation. Dive right into the lectures here. And if you’d prefer to see Feynman (as opposed to read Feynman), we would encourage you to watch ‘The Character of Physical Law,’ Feynman’s seven-part lecture series recorded at Cornell in 1964. Another 37 physics courses, most in video, can be found in our collection of Free Online Courses.

http://www.feynmanlectures.caltech.edu/

Table of Contents below in this link

http://www.feynmanlectures.caltech.edu/I_toc.html

Enjoy...

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I have literally read my first set of the Feynman Lectures to tatters and scraps. I have lots of books on science and math but the three volume set is the only one I have read many, many times over. Of course I have replaced my original set with the hard bound version. But I filled the margins on my original sets with thousands of marginal notes.

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I get them from the library every now and then -- actually happy to find them on the shelves because no matter where I've lived - East Lansing, Ann Arbor, Columbus, and now Austin - they are checked out pretty often. I have six or eight "Feynman" books, the biographies, of course (Surely, You're Joking, What do you Care, and Gleick's), but also The Character of Physical Law, Six Easy Pieces, Feynman's Lost Lecture. For my review of Gleick's book on my blog, I compiled a bibliography of holding at the City of Austin Library: 28 titles.

When my daughter was a child, I used to read Surely You're Joking for bedtime stories.

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Thanks for posting that, Adam! I'm sure all of Feynman's lectures are very interesting, but I had to skip straight to chapter 37 and read his excellent description of the double slit experiment. I wasn't aware of all the details of the phenomenon, e.g., what happens when the intensity or wavelength of the light is changed, but Feynman is able to explain it all with incredible clarity.

Darrell

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Thanks for posting that, Adam! I'm sure all of Feynman's lectures are very interesting, but I had to skip straight to chapter 37 and read his excellent description of the double slit experiment. I wasn't aware of all the details of the phenomenon, e.g., what happens when the intensity or wavelength of the light is changed, but Feynman is able to explain it all with incredible clarity.

Darrell

I hope you don't take Feynman's description of the double slit experiment as the last word on the subject. The video of the lecture of 1964 was the same year J.B. Bell's paper was published on the "Bell Inequalities" which placed the de Broglie-Bohm interpretation [deterministic physics] on even footing with the interpretation Feynman lectures about [indeterministic physics].

Dennis

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Hi Dennis,

I'm not taking anybody's word to be the last word on the subject. I was simply referring to Feynman's description of the phenomenon. I had used the word, "experiment," rather than "phenomenon," but then I remembered that he wasn't describing any actual experiment, just a thought experiment. However, I was grateful for the additional information. Many explanations of the double slit experiment make it sound like simply observing the electron causes its behavior to change which, of course, makes no sense. His explanation makes it clear that it is the presence of the light that makes the behavior change. Changes in the intensity and wavelength of the light cause the behavior of the electron to change in exactly the manner that one would expect if it is the presence of the light that is altering the behavior of the electron. Of course, it would be interesting to look up the actual experiments to make sure that they confirm exactly the explanation that Feynman gives of the thought experiment.

As for the de Broglie-Bohm interpretation, I have real problems with any non-local theory of physics. I'm also not convinced that Bell's Inequalities show what people think they show, but I'd be interested to discuss the issue with anyone that understands the experimental evidence.

Darrell

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In the physical sciences there are latest words but no "last words". We are always learning new stuff and you can safely bet your favorite theory will require modification or replacement in due course.

Ba'al Chatzaf

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As for the de Broglie-Bohm interpretation, I have real problems with any non-local theory of physics. I'm also not convinced that Bell's Inequalities show what people think they show, but I'd be interested to discuss the issue with anyone that understands the experimental evidence.

All successful quantum theories are non-local theories of physics. Non-local means different things in different interpretations [as explained by Bell]. In orthodox quantum mechanics it means that a quantum object has no identity or causality associated with it - it does not exist in any particular location in reality until the quantum measurement occurs - QM is all about the interference and collapse of probability waves [how that happens is never actually explained] leading to the quantum object finally having a specific location. In the de Broglie-Bohm interpretation non-local simply means very fast. So beware of the term non-local, it is used incorrectly as often as not and many mistakenly act like it means the same thing in different interpretations - it does not.

Dennis

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As for the de Broglie-Bohm interpretation, I have real problems with any non-local theory of physics. I'm also not convinced that Bell's Inequalities show what people think they show, but I'd be interested to discuss the issue with anyone that understands the experimental evidence.

All successful quantum theories are non-local theories of physics. Non-local means different things in different interpretations [as explained by Bell]. In orthodox quantum mechanics it means that a quantum object has no identity or causality associated with it - it does not exist in any particular location in reality until the quantum measurement occurs - QM is all about the interference and collapse of probability waves [how that happens is never actually explained] leading to the quantum object finally having a specific location. In the de Broglie-Bohm interpretation non-local simply means very fast. So beware of the term non-local, it is used incorrectly as often as not and many mistakenly act like it means the same thing in different interpretations - it does not.

Dennis

Hi Dennis,

In Feynman's lecture, chapter 37, he doesn't say that an electron has no identity or causality or that it doesn't exist in any particular location. He simply says we can't know. The Copenhagen Interpretation might say that, but Feynman doesn't say that, at least not in chapter 37.

Feynman specifically doesn't say that the act of measurement causes the electron to assume a particular state. In fact, he makes it very clear that it is the light source that causes the electron to behave in a particular way, not the act of observation. That is one of the things I liked about his description.

So, perhaps there is currently no good interpretation of QM.

Darrell

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As for the de Broglie-Bohm interpretation, I have real problems with any non-local theory of physics. I'm also not convinced that Bell's Inequalities show what people think they show, but I'd be interested to discuss the issue with anyone that understands the experimental evidence.

All successful quantum theories are non-local theories of physics. Non-local means different things in different interpretations [as explained by Bell]. In orthodox quantum mechanics it means that a quantum object has no identity or causality associated with it - it does not exist in any particular location in reality until the quantum measurement occurs - QM is all about the interference and collapse of probability waves [how that happens is never actually explained] leading to the quantum object finally having a specific location. In the de Broglie-Bohm interpretation non-local simply means very fast. So beware of the term non-local, it is used incorrectly as often as not and many mistakenly act like it means the same thing in different interpretations - it does not.

Dennis

Hi Dennis,

In Feynman's lecture, chapter 37, he doesn't say that an electron has no identity or causality or that it doesn't exist in any particular location. He simply says we can't know. The Copenhagen Interpretation might say that, but Feynman doesn't say that, at least not in chapter 37.

Feynman specifically doesn't say that the act of measurement causes the electron to assume a particular state. In fact, he makes it very clear that it is the light source that causes the electron to behave in a particular way, not the act of observation. That is one of the things I liked about his description.

So, perhaps there is currently no good interpretation of QM.

Darrell

Feynman was the main spokesman for the Copenhagen Interpretation after Bohr died and defended it on every front. Saying we can't know is part of the indeterministic view. Another aspect of the indeterministic view is the almost religious fervor over the "Heisenberg Uncertainty Principle" - (the light source that causes the electron to behave in a particular way). It has been shown that the "Heinsenberg Uncertainty Principle" is not a principle at all but a shorthand notation for an imprecise set of beliefs concerning quantum observation. In the last couple years experiment and theory have shown that a series of weak observations can get around the limits imposed by the "Heinsenberg Uncertainty Principle".

The other part of Feynman's philosophical interpretation is that no one understands QM. The generic de Broglie-Bohm interpretation requires improvement [something I am interested in] but I view it as a good interpretation of QM for the most part. Feynman was well aware of the work in de Broglie-Bohm QM. When J.S. Bell spoke of the "scandal within physics" concerning the rightful place of de Broglie-Bohm QM to be taught along side orthodox QM as an equal partner I'm sure that comment included Feynman since his views were being taught in a vacuum as the orthodox view without mention of alternative interpretations.

Dennis

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As for the de Broglie-Bohm interpretation, I have real problems with any non-local theory of physics. I'm also not convinced that Bell's Inequalities show what people think they show, but I'd be interested to discuss the issue with anyone that understands the experimental evidence.

All successful quantum theories are non-local theories of physics. Non-local means different things in different interpretations [as explained by Bell]. In orthodox quantum mechanics it means that a quantum object has no identity or causality associated with it - it does not exist in any particular location in reality until the quantum measurement occurs - QM is all about the interference and collapse of probability waves [how that happens is never actually explained] leading to the quantum object finally having a specific location. In the de Broglie-Bohm interpretation non-local simply means very fast. So beware of the term non-local, it is used incorrectly as often as not and many mistakenly act like it means the same thing in different interpretations - it does not.

Dennis

Hi Dennis,

In Feynman's lecture, chapter 37, he doesn't say that an electron has no identity or causality or that it doesn't exist in any particular location. He simply says we can't know. The Copenhagen Interpretation might say that, but Feynman doesn't say that, at least not in chapter 37.

Feynman specifically doesn't say that the act of measurement causes the electron to assume a particular state. In fact, he makes it very clear that it is the light source that causes the electron to behave in a particular way, not the act of observation. That is one of the things I liked about his description.

So, perhaps there is currently no good interpretation of QM.

Darrell

Feynman was the main spokesman for the Copenhagen Interpretation after Bohr died and defended it on every front. Saying we can't know is part of the indeterministic view. Another aspect of the indeterministic view is the almost religious fervor over the "Heisenberg Uncertainty Principle" - (the light source that causes the electron to behave in a particular way). It has been shown that the "Heinsenberg Uncertainty Principle" is not a principle at all but a shorthand notation for an imprecise set of beliefs concerning quantum observation. In the last couple years experiment and theory have shown that a series of weak observations can get around the limits imposed by the "Heinsenberg Uncertainty Principle".

The other part of Feynman's philosophical interpretation is that no one understands QM. The generic de Broglie-Bohm interpretation requires improvement [something I am interested in] but I view it as a good interpretation of QM for the most part. Feynman was well aware of the work in de Broglie-Bohm QM. When J.S. Bell spoke of the "scandal within physics" concerning the rightful place of de Broglie-Bohm QM to be taught along side orthodox QM as an equal partner I'm sure that comment included Feynman since his views were being taught in a vacuum as the orthodox view without mention of alternative interpretations.

Dennis

Even so, the man-scale comprehension we grasp during the first ten years of our lives, that scale in which we actually live and perceive is inadequate to describe what is going on at the atomic and sub-atomic level.

That is why our grasp of Nature has to be indirect. Most of the good stuff is so small that the wave lengths to which we are sensitive directly (visible light and some heat) are way too large to resolve the main actors in reality.

We must be content with theories and "interpretations" (which are really analogies and metaphors) since we cannot directly perceive what is -really- going on.

Ba'al Chatzaf

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A policeman pulled over an electron for speeding. "Did you know you were going 120 kilometers per hour?" asked the policeman. "Oh damn, now I'm really lost," replied the electron.

Feynman was the main spokesman for the Copenhagen Interpretation after Bohr died and defended it on every front. Saying we can't know is part of the indeterministic view. Another aspect of the indeterministic view is the almost religious fervor over the "Heisenberg Uncertainty Principle" - (the light source that causes the electron to behave in a particular way). It has been shown that the "Heinsenberg Uncertainty Principle" is not a principle at all but a shorthand notation for an imprecise set of beliefs concerning quantum observation. In the last couple years experiment and theory have shown that a series of weak observations can get around the limits imposed by the "Heinsenberg Uncertainty Principle".

The other part of Feynman's philosophical interpretation is that no one understands QM. The generic de Broglie-Bohm interpretation requires improvement [something I am interested in] but I view it as a good interpretation of QM for the most part. Feynman was well aware of the work in de Broglie-Bohm QM. When J.S. Bell spoke of the "scandal within physics" concerning the rightful place of de Broglie-Bohm QM to be taught along side orthodox QM as an equal partner I'm sure that comment included Feynman since his views were being taught in a vacuum as the orthodox view without mention of alternative interpretations.

Dennis

A light source causing the behavior of an electron to change strikes me as a purely experimental result. If the intensity of the light source is turned up, electrons behave like particles. If it is turned down, electrons behave more like waves --- only a fraction of the electrons behave like particles; the rest behave like waves. If the wavelength of the light is decreased, the electrons behave more like particles. If the wavelength is increased, they behave more like waves. Ok, "wave" and "particle" are interpretations, but I'm talking about the interference pattern which is just an experimental observation. So far, no interpretation has been placed on the results.

The results of the double slit experiment are taken as evidence for the Heisenberg Uncertainty Principle, but they could simply be viewed as a result concerning the interaction of light (electromagnetic radiation) with electrons. It is certainly not surprising that the two interact.

Originally, the Copenhagen Interpretation put the emphasis on the observation of the outcome of the experiment. It was said that the state of a system was indeterminate until it was observed. That, of course, led to absurd paradoxes such as the case of Shrodinger's Cat. But, there is nothing in Feynman's description of the double slit experiment that would imply that the state of the electron depends upon whether it is being observed or not. That is, there may or may not be a scientist or even a measuring device present in the room with the electron source, the light source, and the double slit screen. One would presume that electrons would continue to behave as waves or particles in whatever proportions are predicted by the theory independent of any observer. Such a conclusion would be consistent with the description given in chapter 37.

I had thought that the Copenhagen Interpretation had generally been abandoned in favor of a more physical interpretation such as the one given for the double slit experiment in chapter 37.

It is true --- or at least it was true when I was in school --- that physicists continue to talk about "probability waves." Of course, that makes little sense, except from the standpoint of an observer. That is, a probability wave cannot be something physical. A real system must evolve according to physical waves (or according to some other principle).

However, none of the above eases my concern with the idea of instantaneous action at a distance. So far, I have not been convinced that long-range quantum entanglement is possible. And what about its relationship to Relativity and causality?

The notion of one enormous Schrodinger wave equation governing everything also bothers me. It wouldn't bother me that much if one could neglect most of the terms, but the notion of instantaneous action at a distance means that it is not practically possible to neglect the states of other particles that aren't nearby. Of course, sometimes Mother Nature makes our lives difficult, so perhaps I'm just grousing, but it would seem to me that this could be a real impasse for the theory.

BTW, if you have any references for how to get around the Uncertainty Principle using weak observations, I would interested to see them.

Darrell

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Look up the photo electric effect when you get a change. BTW, it was the paper on the Photoelectric Effect that got Einstein his Nobel Prize.

An energetic enough photon will knock electrons out of metals.

Ba'al Chatzaf

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It is true --- or at least it was true when I was in school --- that physicists continue to talk about "probability waves." Of course, that makes little sense, except from the standpoint of an observer. That is, a probability wave cannot be something physical. A real system must evolve according to physical waves (or according to some other principle).

However, none of the above eases my concern with the idea of instantaneous action at a distance. So far, I have not been convinced that long-range quantum entanglement is possible. And what about its relationship to Relativity and causality?

The notion of one enormous Schrodinger wave equation governing everything also bothers me. It wouldn't bother me that much if one could neglect most of the terms, but the notion of instantaneous action at a distance means that it is not practically possible to neglect the states of other particles that aren't nearby. Of course, sometimes Mother Nature makes our lives difficult, so perhaps I'm just grousing, but it would seem to me that this could be a real impasse for the theory.

BTW, if you have any references for how to get around the Uncertainty Principle using weak observations, I would interested to see them.

Probability waves do indeed require a means to finally reach a conclusion - that can continues to be kicked down the road without resolution.

The de Broglie - Bohm interpretation in its original form required instantaneous communications. In reality observation only requires it be very fast compared to the speed of light - similar to the difference between the speed of water waves and the speed of light.

Long range entanglement in optical systems has been experimentally demonstrated in the range of 100 km or so. You can demonstrate non-linear chaotic entanglement in home experiments in the range of tens of meters using mechanical pendulum clocks, I'm sure it could be done in the km range if you had the money. Hurricane and weather systems demonstrate non-linear chaotic entanglement on the scale of thousands of kilometers.

There is no issue of causality violations in extended LET Relativity - which can modified to include supraluminal effects. Einstein's Special Relativity cannot adapt.

The view of everything being a single enormous Schrodinger wave equation would be like taking all the sound waves in the ocean and calling it a single wave equation. It might be helpful if you read the papers of Gregory S. Duane concerning what chaotic synchronization [entanglement] as applied to QM is really all about. In idealized QM everything everywhere is connected - in what you can actually experimentally determine the effects may be long distance but there is no reason to believe they perfectly extend to every part of the universe. A whale may be able to send out a call for a thousand kilometers but that does not mean the sound can be heard absolutely everywhere.

An older but very good reference about how weak measurements and the double slit experiment.

http://phys.org/news/2011-06-quantum-physics-photons-two-slit-interferometer.html

Dennis

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