Reddit reviews QED: The Strange Theory of Light and Matter
We found 32 Reddit comments about QED: The Strange Theory of Light and Matter. Here are the top ones, ranked by their Reddit score.
Used Book in Good Condition
Oh? Really? Refraction is easy peasy, eh?
You may have heard that the speed of light slows down depending on the density of the material through which it passes.
But in reality, light sniffs out every possible path, then chooses the least resistant.
Every photon, trillions upon trillions upon trillions of them, considers every possible path through space! When you start to think about "how could such a thing even be possible?" then you get really mindblown.
Check out QED by Feynman for some mindbending. I'd recommend reading the book, but you could watch the lectures.
EDIT: For the truly curious, you can read Chapter 2 of the book here. It's the most accurate refraction ELI5 that exists (or probably will ever exist). It's probably impossible to simplify the explanation any further.
Well here's how it went down.
But I still love physics. I read QED for fun. I just can't handle anything beyond Taylor and Maclaurin series without someone at my back yelling at me I guess. Also I hated memorizing integrals.
On the tests I would get all the bonus questions right (which tested actual understanding of the concepts) and I'd fail on the actual test due to lack of time (because that part of the test really tested how often you had seen that problem or one similar before).
Three minor corrections:
If anyone is interested in an accessible introduction to this material, read Richard Feynman's QED.
The lectures are $2 on the used market. Well worth the price.
He also covers the dual slit experiment and provides a framework in which the results make sense.
The answer to this is much, much deeper than any of the comments so far. The answer to "How does" is not "4%". The answer is in Quantum Electrodynamics.
I have to run to work, and Richard Feynman is much better at explaining things than me, so I'll point you to his book QED which is dedicated to answering this question as a way to explain QED.
Sorry to have to run because this is fascinating, but to give an accurate answer that really hits on the principles behind it, takes about 20 pages from one of the smartest men who ever lived. I couldn't recommend the book more - it is accessible to anyone of reasonable intelligence willing to read it carefully, and unlocks one of the great mysteries of nature in an entertaining and exciting way.
Eh, first you have to read up on quantum mechanics and get a decent understanding of quantum mechanical spin and quantum numbers in general. Something like Shankar - Principles of Quantum Mechanics, though there are tons of textbooks on it. You won't really get into particle physics, but should read at least to the point of understanding addition of angular momentum and spin (typically in context of hydrogen atom).
Then a text on particle physics like Griffiths' Intro To Elementary Particle Physics. (You could also start Griffiths' Intro to QM).
You could also consult free resources like the particle data group, but their reviews will be largely gibberish if you don't understand the basics of QM / particle physics / group theory. (Articles like Quark Model, or Naming Scheme for Hadrons).
If you are looking at hobby-level interest without getting into any math/textbooks, the best I can suggest is Feynman's QED but it won't talk about isospin or hadrons or particle naming conventions but is a great layman introduction to quantum electrodynamics.
Read the QED lectures by Feynman, you won't get a better, more accessible explanation than that
Recently I've read Feynman's The Strange Theory of Light and Matter. It's a nice "introduction" to the world of quantum physics. ((Also available online on certain sites.))
QED: The Strange Theory of Light and Matter, Richard P. Feynman (Princeton Science Library)
http://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170
To start, you need to you learn that eveything is made from complex waves of probability and that is the only way the math works. This short and inexpensive book is a work of art, accessible by the "intelligent layman". Then google the amazing Feynman!
I was going to ask you if it's approachable for a non-physicist like myself. I mean, it's Feynman.
However, rather than ask I looked to Amazon.com.
>Feynman makes it easy for the curious amateur to understand. This book is accessible and mind-blowing. Everyone should read it. And there is little if any math so don't be intimidated.
Well, then. I guess I'll be reading it!
EDIT: Here's the book
Oh, and thank you!
This may not be what you are looking for, but Feynman was a master of explanations. He wrote a wonderful book on quantum electrodynamics that you should absolutely check out called QED: The Strange Theory of Light and Matter. It will give you a pretty intuitive look at some of the ideas in QED.
This guy can!
http://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170/ref=sr_1_2
Feynman's QED
Asimov's non-fiction is good
Godel, Escher, Bach
Einstein's original book
Maxwell's book (lots of math)
> If you want to involve photons in this picture, you can, but it won't help you very much.
I beg to differ. I only really understood what “electricity” is, including said guitar-amp phenomenon, when I got photons in the picture , thus creating a very different model than the one presented by most textbooks on transistor electronics. The stuff that moves at the speed of light when you turn a switch on? Photons. The stuff that actually transfers electromagnetic energy, including wire “electricity”, from a battery/source to charge? Photons. Stuff that binds electrons to protons? Photons. Stuff that get stored in capacitors? Photons. Hell the photon↔electron interaction goes well beyond “light” or “electricity” and do most things in the universe! (except gravity and nuclear phenomena). I don’t feel qualified to explain it all in quantum terms but I got the better picture from Richard Feynman’s QED, which I heartily recommend to any curious layman. (Also, this page).
Indeed yes, there isn't so much absorbtion and reemission of quanta as i understand it as does the substance act like a matrix or diffraction grating. Then within the substance you have lots of little broken up waves all interacting with each other, canceling each other out in parts and bolstering each other in others. The 'super wave' made up of all these interactions propagates at slower than light speed, and potentially at an angle. Come out the other side (into a vaccum again) and there's no diffraction, no 'super wave' but back to light propagating at 'light speed again'.
There's probably a good quantum analogy too, but I don't recall it.
The thing to always remember is that these forces aren't quantum particles or idealized waves, those are just the best models we have for something we don't fully understand.
Read Feynman's QED, its short, written for the layman and completely awesome. It will also blow your freaking mind.
I think the best answer is: since photons don't come with nametags, there's no way to tell, but in most cases, the light behaves as if it's the same photon. There are however some properties of light (diffraction, for instance) where thinking of each point in space as a source of new photons is useful.
For extra credit: the same is true of matter.
Not 100% related, but for more on this sort of thing check out Richard Feynman's short book "QED: The Strange Theory of Light and Matter". It's intended for ordinary laypeople, which says a lot about Feynman's confidence in laypeople, but it's great for the dedicated reader.
I have been googling for the past hour and I think they are absorbed, but they are emitted with more-or-less the same wavelength, resulting in more-or-less the same image.
Photons travel at c between the atoms, but the absorption and emission causes an average slower speed, and thus a bend in its path. From the linked article:
> By "absorption" I mean that the energy of the photon causes an electron of
the atom to be kicked to a higher energy level, and the photon ceases to
exist. Then, after a very small time delay, the electron goes back to its
original (usually ground state) energy and "emits" a photon of the same
energy (and thus same frequency and thus same wavelength) as the original
"absorbed" photon.
So to answer your question, yes, refraction is absorption->emission. The article in OP sorta glosses over this, ("This is not due to gravity, but refraction as the lens of our air slants its path before its final plummet to the nighttime country-side below.") perhaps to keep the theme of following one photon on its journey. From what I've read online, a good resource for more info on this is QED: The Strange Theory of Light and Matter by Richard Feynman.
I think my original question is more of philosophical identity (is it really the "same" photon?) than of physics.
Thanks for asking these questions, because I learned a lot in researching the answers lol. All this info made the original article seem even less science-based, but I still think it illustrates the awesome forces at work in this stellar hobby.
Also, someone else mentioned Feynman's book, called QED. It's a great read.
He did, sort of, in his book :)
http://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170
Looking on their website it seems as if they do not let outside people borrow from their library, sorry :(.
I know many libraries have "partnerships" for the lack of a better word, where if you try to borrow a book from the library, and they don't have it, they will request it from somewhere else they are partnered with and get it for you.
Some ideas of books:
For my undergraduate astrophysics class I used - Foundations of Astrophysics by Ryden and Peterson, ISBN13: 978-0-321-59558-4
I have also used (more advanced, graduate level) - An Introduction to Modern Astrophysics by Carroll and Ostlie, ISBN13: 978-0-805-30402-2
There are plenty of other undergraduate text books for astrophysics, but those are the only two I have experience with.
Some other books that may be just fun reads and aren't text books:
A Brief History of Time - Hawking
QED: The Strange Theory of Light and Matter - Feynman
Random popular science books:
Parallel Worlds - Kaku (or anything else by him Michio Kaku)
Cosmos - Sagan
Dark Cosmos - Hooper
or anything by Green, Krauss, Tyson, etc.
Videos to watch:
I would also suggest, if you have an hour to burn, watching this video by Lawrence Krauss. I watched it early on in my physics career and loved it, check it out:
Lawrence Krauss - A Universe From Nothing
Also this video is some what related:
Sean Carroll - Origin of the Universe and the Arrow of Time
Hope you enjoy!
Edit: Formatting.
Try reading some of Feynman's lectures - he explains these difficult concepts very well.
Maybe The Strange Theory of Light and Matter would help.
I'm sure you can find a source on the internet pretty easily if you don't want to buy a printed copy.
If you want to understand how reflection behaves in a "true" way, read Feynman's QED. Transcripts of popular science lectures. They're not exactly simple to understand, but they were designed to be at least somewhat accessible.
You must realize you are the box and the box is you. With the same instance that you understand your box, your box understands you. This means quantum mechanics may substitute for a cozier box?
On a sidenote however, I understood quatum mechanics at least a little better after reading QED The Strange Theory of Light and Matter I recommend it.
The man that said "if you think you understand when to mechanics, you do not understand quantum mechanics" is Richard Feynman. He also wrote a book that explains quantum mechanics, called QED.
QED by Feynman
The Strange Theory of Light and Matter for an intro to QED.
Perhaps a lot will be clearer if you get the quantum nature of the measurement of light's polarization. Classically, light is a transverse electromagnetic wave. When one measures a photon's polarization it assumes a definite value, i.e. some orientation. To say that light is unpolarized means that all electric field directions of every photon in a beam will have equal probability to be measured. If the light is polarized then it can be measured in one of only two states. "Circular polarization" means each possible state is described by a plane waves of equal amplitude but differing in phase by 90°. If the light is "elliptically polarized" then it's unmeasured state is described by two simultaneous plane waves of differing amplitude related in phase by 90°. It can also be called elliptically polarized if the amplitudes of the two states are equal but the relative phase is other than 90°. So an unpolarized beam of photons say, or a single photon with a polarization at some angle relative to your measuring polarizer say, is not split into two when sent through a polarizer, rather each photon takes one path or another according to probability.
Concerning your next group of questions about how light propagates through dielectric solids like glass... There is only free propagation, absorption, and scattering. Scattering can be either elastic or inelastic. Scattering theory is a rich subject because materials are so diverse in composition. The most common form of scattering in isotropic media like the atmosphere and dielectric solids composed of small molecules is an elastic form of scattering called Rayleigh scattering. Rayleigh scattering occurs when a photon penetrates into a medium composed of particles whose sizes are much smaller than the wavelength of the incident photon. In this scattering process, the energy (and therefore the wavelength) of the incident photon is conserved and only its direction is changed. Rayleigh scattering has a simple classical origin: the electrons in the atoms, molecules or small particles radiate like dipole antennas when they are forced to oscillate by an applied electromagnetic field. This is not an absorption and re-emission. If the scattering sources are stationary, then this secondary radiation is phase locked to the driving electromagnetic field. So perhaps this is what you mean by "coherent transmission". But even for a truly coherent source of photons, from a laser say, the coherence length is shorted by the presence of the dielectric.
Lastly, your bonus question... You need to read Richard Feynman's, QED: The Strange Theory of Light and Matter. Light propagates as a wave, even single photons. It therefore takes all possible paths, not just the path of least time! It's just that only those paths which arrive at the detector in phase will result in a non-zero amplitude. And for a single ray of light passing from one isotropic medium to another of different index of refraction, there is only one path that satisfies that condition, the path of least time. Anyway, you will love the book and will come away understanding light much better.
Recommended reading on the subject. Here's my explanation, though this is outside my expertises, and a physics major should offer a more comprehensive answer. But here we go.
When a photon strikes an atom, it causes an electron to jump to its next energy level. The photon is absorbed in the process, and its energy is conserved by an increase in the electron energy level. The atom won't like the configuration, so the electron will soon drop back down to the lower energy level, releasing a photon. This is called reflection.
Now, when you get enough atoms lined up in the right orientation, the image will be conserved. The book I provided offers an awesome explanation of the phenomena. Simply, the light can be considered to be reflected off the front surface and back surface. You know how light is sometimes thought of a wave? It is useful to think of it in this way for this explanation. The reflections from the back and front surface will interfere (two waves taking up the same space). If a peak meets with a valley, the two cancel. If a peak meets with another peak, it will interfere 'constructively', and the light will be preserved.
Now, if the surface is nice and smooth, a clear reflection will be seen as a result of this interaction between the two lights. reflections off glass windows works in this manner. When you are in a bright room at night, the light reflecting off from the room is brighter than the light coming in from outside. This is why you have a hard time seeing through your windows at night, and it helps to shield the glass from the light with your hands. BUT I DIGRESS
Now, you are correct in thinking that the absorption/emission event sends the photon in a random direction. But the waves associated with these random reflections cancel each other out in most cases. The only photon that survives the mass extinction are the ones that reflected with an angle of reflection equal to the angle of incidence.
But really, read the book I linked. It explains this all much better than I can.
I would recommend reading, Feynman explains modern physics beautifully and tailors his writing to someone with very little math knowledge
Amazon Link
QED: The Strange Theory of Light and Matter
It's short (less that 200 pages), it's written so a high school student can understand it and for many years I have gained new incite by thinking back on this book.
http://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170
(I have many others - I just wanted to make certain this book appeared.)
Oh good! It's even more BS-ey than I had realized!
My knowledge of quantum physics is limited to what one can learn from popular books (1, 2, 3 ). Could you try to explain the differences between the underlying models/assumptions on which Orch-OR is based, and the models/assumptions in established/standard physics? I would appreciate it.
Yes. From "The High Frontier", a book on making space colonies, you could deflect meteors - even nonmetallic - from a colony with an electric field. It required a charge of about two gigavolts to be maintained across the whole of it.
This is costly. And any visiting craft would have to be neutralized relative to whatever charge the colony holds.
Just coating a colony in slag is pretty good; sure, spin up will be harder, but... well, reasons previously listed.
I'm reminded of a conversation a friend had with me; a force field is basically something that would repel an object from contact with the field, right? And you'd need some sort of stabilizing element, right? Something spread across the whole field, probable uniformly?
Something like atoms?
What with the nucleus holding it together and the electrons around it providing the desired electric field?
Yeah. A sheet of strong plastic is essentially a force field.
BUT, that's not nearly as cool.
So you could make an electric field strong enough to repel something moving like a meteor, but... well, here's food for thought. Cathode ray TV's and monitors operate at 35Kv or lower. And they are designed to fail if they over voltage, because they shoot beams of electrons through/at a metal screen, and would deliver X-rays to the viewer if they didn't have such circuits.
Why did you think they were made of lead/strontium glass? Rhetorical question, it's to not irradiate the user.
So, having metal buttons on your person may well enough end up giving you cancer. Not so bad if it's your only choice, or you have a short time to live anyway.
Now, maybe if you could entrap differently charged ions in two fields layered over each other, you'd just need like, a mesh to generate and hold the fields, and then when an object passes through the fields, it'd explosively short it. Sorta like ablative armor but... This may still end badly for the user. Layer it, perhaps?
We do have a very good understanding of electricity on the atomic level; Quantum Electro Dynamics. Feynman wrote a really great introduction to it - he was a great teacher, and was one of the inventors of the theory. It's called "QED: The Strange Theory of Light and Matter".
Gravity is also pretty solid; Laplace fixed our understanding of orbital mechanics in the Napoleonic age. Whooole lot of differential equations there.