A great professor. I never met such a good professor before. His explanation is clear and systematic. If I have met him before, I might do a Phd in physics.
@@jacobvandijk6525 wow didn't expect to see a reply haha. Well, I really wouldn't mind people mispronouncing my name at all. Just read it however it seems fit in whatever language we're currently speaking. My point was that sometimes people will get too caught up in expecting others to pronounce certain sounds correctly while overlooking the more subtle ones. But hey, if you wanna learn it, I think that's great :)
That's right, jacob. Prof. Luis Alvarez (of Los Alamos and other fame) noted it many years ago, explicitly, in his self-titled memoir. In French "de" is pronounced "duh" so it'd be "duh BROY". This professor does such an outstanding job and is such a good teacher, no way i'm criticizing him over this, but once you know how the name is pronounced it just seems odd to hear it pronounced "de broh glee."
@len39f 0 seconds ago I don't know if it's just me listening to these lectures over and over, but his explanation here is so clear now and illuminating. Very appreciative of his consumate knowledge and exposition.
Square of the wave function in Schrodinger equation determines the probability of finding the particle at some point. For example, If you plot a graph of the radial probability function of the broader wave function squared multiplied to 4•pi•r²•dr vs radius r of an atom, you get the radial probability distribution of electrons in the atom by checking number of nodes
Hola, que signfica que las ondas de materia sean probabilisticas? No creo que signifique que son una mera funcion. Entonces en que campo de la fisica se propagan? Teniendo en cuenta que las ondas mecanicas se propagan en la materia, las electromagneticas en el campo electro magnetico, y estas? Las ondas materiales en que campo se propagan?
9:44 I think there's an error. The intensity pattern drawn by him on the screen is that of single slit diffraction and not double slit interference. But he's correct with the dotted explanation.
No, a single split gives no stripe pattern at all: there's only one single wide line where the wave hits the closest to the split and continuous fading from this central line (more like a Gauss curve).
De Broglie's thesis was so outragous that his examiners were not sure what to make of it. They asked Einstein for his opinion. Einstein loved the idea and recommended that he be granted the PhD. He got his PhD
how can this equation be true if the derivation relies on photons being massless? Is there a reason or is it just an assumption that massive particles obey the same equation as photons?
The current best estimate for the mass of the photon is that it is less than 1e-18eV/c^2. That is completely negligible for any of the physics we are doing at the moment because it corresponds to a wavelength on the order of 1e12m or about a billion km. Since we currently can't build antennas that are nearly that long, a direct test for a breakdown of Maxwell's equations at the level is not possible at the moment.
three ( 3 ) formulas is ok seven ( 7 ) formulas is missing drei ( 3 ) formula sind vertig sieben formula sind fehlen üç ( 3 ) formül tamam yedi ( 7 ) formül eksik
Yes, a photon is both a wave and a particle. But it is also two more things: A word ("photon"), and a squiggle of ink on paper (or chalk on board). And of course, it is all four things at once, though at different times it is more of one than the others. "Reductionism" (the Greek definition) says that the entire ontological nature of photons (indeed of all the universe) can be learned via their names and features / attributes / categories, expressible in words or ink. It's a big claim. Yes, John Bell proved that there are no hidden variables in Schrodinger's equation. That is, no hidden features /attributes / categories of particles expressible in ink jots. (Remember: no categories, no math). But he could not rule out other factors that have *no* categories or features. For indeed, it is quite possible that below the Planck length, categories lose all meaning. See the proton, whose size is both bigger and smaller than its components, depending on how you measure it. Or can there be parts of the universe that have no features at? Or both have them and do not have them? Because where there are no categories, both "both" and "neither" have no meaning? There very well could, but of course we humans (whose cortexes require categories, via the Vernon Mountcastle algorithm) could not discuss them.
See this link ocw.mit.edu/courses/physics/8-04-quantum-physics-i-spring-2016/lecture-notes/ Or, search "8.04 MIT" on Google and click the first link then go to the notes section.
Oh my, matter is waves? This man if nothing else is trying to be honest. But then again, he says and writes @5:09 “waves of what” his response to his own question is “probability amplitudes”. Now consider this, what is waving? Can a probability amplitude make a wave? The answer is no. Only physical things wave (even if their substance is unknown) and an idea which is what a "probability amplitude" is, can’t wave. So this professor abandons logic @5:09 and leaves me back to square one, which is, what is reality.
I think you misunderstand when you think the particles "are" waves of probability amplitudes.The point of the wave particle duality is that they merely exhibit wave "properties" (certain properties that are also observed in the physical waves you mention), so he is not saying they are one in the same. Also you make an assumption that only macro physical things can wave (even though these are also fundamentally made of particles), but examples of this assumption being false are gravitational waves and waves in the electromagnetic field (which is light).
@@stephanpotgieter3236 With all due respect your opinion and belief adds to my understanding. At what mass does a particle lose its ability to exhibit wave properties, and why? Waves can pass through two slits simultaneously but particles cannot. To claim that particles merely exhibit wave properties means what, that they are not always waves? As to gravity or light making waves one must assume that something physical is waving, which today, as an idea is not acceptable. So, when this professor writes “waves of what” and answers “probability amplitudes” he is being unclear. What he means by “probability” is, if it is in existence (real, reality) and by the word “amplitude” its solidity (degree of being real). With all due respect he is teaching others to be vague and to ignore the missing piece of the biggest puzzle facing physics today, which is: What is reality?
Yes this MIT professor is confused. Schroedinger relied on de Broglie by trying to ignore the fact that de Broglie was critiquing Einstein's relativity. So now de Broglie's "pilot wave" has been proven to be real (not just a mathematical construct). Yakir Aharonov: "There is a non-local exchange that depends on the modular variable....I'm saying that I have now an intuitive picture to understand interference by saying that when a particle moves through two slits, it always goes through one slit or the other, but it knows which other slit, the slit through which it did not go, whether it is open or not, because there are nonlocal equations of motion." Finally making sense of the double-slit experiment (2017, Aharonov): The nonlocal equations of motion in the Heisenberg picture thus allow us to consider a particle going through only one of the slits, but it nevertheless has nonlocal information regarding the other slit.... The Heisenberg picture, however, offers a different explanation for the loss of interference that is not in the language of collapse: if one of the slits is closed by the experimenter, a nonlocal exchange of modular momentum with the particle occurs....Alternatively, in the Heisenberg picture, the particle has both a definite location and a nonlocal modular momentum that can “sense” the presence of the other slit and therefore, create interference." as John Bell states: "Is it not clear from the diffraction and interference patterns, that the motion of the particle is directed by the wave?" Grant Sanderson, math/science Stanford: "Unlike the doppler radar case where the ambiguity arose because waves were being used to measure an object with a definite distance and speed; what we're seeing here is the particle IS the wave - so the spread out over space and over momentum is not some artifact of imperfect measurement techniques; It's a spread fundamental to what the particle is: analogous to how a musical note being spread out over time is fundamental to what it even means to be a musical note." Grant Sanderson, Math/science degree, Stanford University
@@voidisyinyangvoidisyinyang885 I really appreciate you taking the time to explain your understanding in this matter. I have nothing against the Louis de Broglie theory, also I am not taken aback by your statement that the pilot wave theory has been proven because you have the freedom to believe it is proven to your own satisfaction. Like earth’s gravity not affecting our moon but just affecting space which affects the moon, likewise an electron interacting with this pilot wave, a quantum 3-D vibration (3-D+ time?). This just transfers the particle from being the wave to reacting to a wave. This pilot wave theory just adds another layer of complexity. I would not like to be the person arguing that an electron can sense a second slit, or in a practical sense the existence of a second slit is physically influencing pilot waves by its existence. The question remains, what is waving which creates reality.
@@sedevacantist1 I just did an upload vid on this - with more details - you can watch in half speed or go to my blog - thanks ruclips.net/video/1m38Asft-fw/видео.html&feature=emb_logo
The required text for the course is: Griffiths, David J. Introduction to Quantum Mechanics. Pearson Prentice Hall, 2004. ISBN: 9780131118928. See ocw.mit.edu/8-04S16 for more readings and materials. Best wishes on your studies!
Trying to say that an alternating current in a straight wire that creates a varying electromagnetic field that propogates outward is a photon seems ridiculous. Calling the Xray frequency electromagnetic waves created by the free electron laser photons seems equally ridiculous.
This professor's voice makes me feel at home. The lectures are good. No stress.
اببب
from one era to another era of quantum mechanics ,,this professor should get a Nobel prize for teaching
The history is important for an understanding of the subject...for me at least.
Excellent teacher
Such great lessons by such great Professor.
What a BEAUTIFUL STORY!!! And beautifully told as well.
Brilliant presentation.
A great professor. I never met such a good professor before. His explanation is clear and systematic. If I have met him before, I might do a Phd in physics.
I wish I was student at MIT right now. I'm a high schooler right now. I love learning.
If one reads physics in depth, de Broglie waves WILL come up.
No idea how I landed here but I’m paying attention like I’m taking a midterm soon
The correct pronunciation of the French name "De Broglie" is: DE BROY.
It's almost like 'the boy', but with a rolling r ;-) Try Google-Translate!
Even if you try pronouncing it correctly, you'll probably still get it wrong anyway, so why bother
@@ArgentavisMagnificens Because you might want your name to be pronounced correctly too. MonacoFerry, right? ;-)
@@jacobvandijk6525 wow didn't expect to see a reply haha. Well, I really wouldn't mind people mispronouncing my name at all. Just read it however it seems fit in whatever language we're currently speaking. My point was that sometimes people will get too caught up in expecting others to pronounce certain sounds correctly while overlooking the more subtle ones. But hey, if you wanna learn it, I think that's great :)
@@ArgentavisMagnificens That's the spirit, man. Do what you like as long as it doesn't hurt someone else (but sometimes that's not easy).
That's right, jacob. Prof. Luis Alvarez (of Los Alamos and other fame) noted it many years ago, explicitly, in his self-titled memoir.
In French "de" is pronounced "duh" so it'd be "duh BROY".
This professor does such an outstanding job and is such a good teacher, no way i'm criticizing him over this, but once you know how the name is pronounced it just seems odd to hear it pronounced "de broh glee."
@len39f
0 seconds ago
I don't know if it's just me listening to these lectures over and over, but his explanation here is so clear now and illuminating. Very appreciative of his consumate knowledge and exposition.
excellent presentation. Profound insights.
felling lucky to see these lecture..
"De broccoli".
Cmon man. "De-broy"
I am so amused by his 'A~ssociate'
I wanna write on that board
It's moving at c; the fastest possible speed in the known universe.
This was just confirmed 👍
Does it work that way..need symmetry?
Squares are probabilities.
So a square represents the probability of ? finding..?.
Wave ---->particle ...no
Particle---> wave..yes?
I'm pure physical.....leaning to that..
Square of the wave function in Schrodinger equation determines the probability of finding the particle at some point. For example, If you plot a graph of the radial probability function of the broader wave function squared multiplied to 4•pi•r²•dr vs radius r of an atom, you get the radial probability distribution of electrons in the atom by checking number of nodes
Expuse este tema en mis primeros años de carrera y recuerdo que entenderlo la primera ves fue una cosa reveladora
Hola, que signfica que las ondas de materia sean probabilisticas? No creo que signifique que son una mera funcion. Entonces en que campo de la fisica se propagan? Teniendo en cuenta que las ondas mecanicas se propagan en la materia, las electromagneticas en el campo electro magnetico, y estas? Las ondas materiales en que campo se propagan?
@@fascistalien No se, un saludo
9:44 I think there's an error. The intensity pattern drawn by him on the screen is that of single slit diffraction and not double slit interference. But he's correct with the dotted explanation.
No, a single split gives no stripe pattern at all: there's only one single wide line where the wave hits the closest to the split and continuous fading from this central line (more like a Gauss curve).
No, check again? Pure interference will not have peaks of reducing amplitude. All maximas will be of the same intensity.
@@ananth1994 I believe that's an ideal situation. In practice, this is exactly what 2 slit interference looks like.
Ah, I see. I'll try it out sometime. :)
The wave is a generalized movement map...
?
What happens when a particle's wavelength reaches to a plank length?
check your question ...what you are saying
The particle resonates with itself to create black holes everywhere in the universe and we're all doomed.
All waves.
De Broglie's thesis was so outragous that his examiners were not sure what to make of it. They asked Einstein for his opinion. Einstein loved the idea and recommended that he be granted the PhD. He got his PhD
He got more than that. He was awarded a Nobel prize in 1929.
Yes!!! I also used to wonder on this, as this was during his PhD!!!!
how can this equation be true if the derivation relies on photons being massless? Is there a reason or is it just an assumption that massive particles obey the same equation as photons?
The current best estimate for the mass of the photon is that it is less than 1e-18eV/c^2. That is completely negligible for any of the physics we are doing at the moment because it corresponds to a wavelength on the order of 1e12m or about a billion km. Since we currently can't build antennas that are nearly that long, a direct test for a breakdown of Maxwell's equations at the level is not possible at the moment.
three ( 3 ) formulas is ok seven ( 7 ) formulas is missing
drei ( 3 ) formula sind vertig sieben formula sind fehlen
üç ( 3 ) formül tamam yedi ( 7 ) formül eksik
I just wanna make you know that if you arrived until this point, I really admire you
De Broglie is pronounced "da broye".
Yes, a photon is both a wave and a particle. But it is also two more things: A word ("photon"), and a squiggle of ink on paper (or chalk on board). And of course, it is all four things at once, though at different times it is more of one than the others. "Reductionism" (the Greek definition) says that the entire ontological nature of photons (indeed of all the universe) can be learned via their names and features / attributes / categories, expressible in words or ink. It's a big claim. Yes, John Bell proved that there are no hidden variables in Schrodinger's equation. That is, no hidden features /attributes / categories of particles expressible in ink jots. (Remember: no categories, no math). But he could not rule out other factors that have *no* categories or features. For indeed, it is quite possible that below the Planck length, categories lose all meaning. See the proton, whose size is both bigger and smaller than its components, depending on how you measure it. Or can there be parts of the universe that have no features at? Or both have them and do not have them? Because where there are no categories, both "both" and "neither" have no meaning? There very well could, but of course we humans (whose cortexes require categories, via the Vernon Mountcastle algorithm) could not discuss them.
WOW ❤
Bravo😁
probablity can be percieved as pressure distribution.
Finally somebody pronounces his name right
This is actually the wrong pronunciation, the correct pronunciation in French is closer to 'de Broy'.
@pandakso3365: I assume you are joking.
Sir, here you told about some links and notes that you'll send in website.... can i get those please????
See this link
ocw.mit.edu/courses/physics/8-04-quantum-physics-i-spring-2016/lecture-notes/
Or, search "8.04 MIT" on Google and click the first link then go to the notes section.
Oh my, matter is waves? This man if nothing else is trying to be honest. But then again, he says and writes @5:09 “waves of what” his response to his own question is “probability amplitudes”. Now consider this, what is waving? Can a probability amplitude make a wave? The answer is no. Only physical things wave (even if their substance is unknown) and an idea which is what a "probability amplitude" is, can’t wave. So this professor abandons logic @5:09 and leaves me back to square one, which is, what is reality.
I think you misunderstand when you think the particles "are" waves of probability amplitudes.The point of the wave particle duality is that they merely exhibit wave "properties" (certain properties that are also observed in the physical waves you mention), so he is not saying they are one in the same. Also you make an assumption that only macro physical things can wave (even though these are also fundamentally made of particles), but examples of this assumption being false are gravitational waves and waves in the electromagnetic field (which is light).
@@stephanpotgieter3236 With all due respect your opinion and belief adds to my understanding. At what mass does a particle lose its ability to exhibit wave properties, and why? Waves can pass through two slits simultaneously but particles cannot. To claim that particles merely exhibit wave properties means what, that they are not always waves? As to gravity or light making waves one must assume that something physical is waving, which today, as an idea is not acceptable.
So, when this professor writes “waves of what” and answers “probability amplitudes” he is being unclear. What he means by “probability” is, if it is in existence (real, reality) and by the word “amplitude” its solidity (degree of being real). With all due respect he is teaching others to be vague and to ignore the missing piece of the biggest puzzle facing physics today, which is: What is reality?
Yes this MIT professor is confused. Schroedinger relied on de Broglie by trying to ignore the fact that de Broglie was critiquing Einstein's relativity. So now de Broglie's "pilot wave" has been proven to be real (not just a mathematical construct). Yakir Aharonov: "There is a non-local exchange that depends on the modular variable....I'm saying that I have now an intuitive picture to understand interference by saying that when a particle moves through two slits, it always goes through one slit or the other, but it knows which other slit, the slit through which it did not go, whether it is open or not, because there are nonlocal equations of motion." Finally making sense of the double-slit experiment (2017, Aharonov): The nonlocal equations of motion in the Heisenberg picture thus allow us to consider a particle going through only one of the slits, but it nevertheless has nonlocal information regarding the other slit.... The Heisenberg picture, however, offers a different explanation for the loss of interference that is not in the language of collapse: if one of the slits is closed by the experimenter, a nonlocal exchange of modular momentum with the particle occurs....Alternatively, in the Heisenberg picture, the particle has both a definite location and a nonlocal modular momentum that can “sense” the presence of the other slit and therefore, create interference." as John Bell states: "Is it not clear from the diffraction and interference patterns, that the motion of the particle is directed by the wave?"
Grant Sanderson, math/science Stanford: "Unlike the doppler radar case where the ambiguity arose because waves were being used to measure an object with a definite distance and speed; what we're seeing here is the particle IS the wave - so the spread out over space and over momentum is not some artifact of imperfect measurement techniques; It's a spread fundamental to what the particle is: analogous to how a musical note being spread out over time is fundamental to what it even means to be a musical note." Grant Sanderson, Math/science degree, Stanford University
@@voidisyinyangvoidisyinyang885 I really appreciate you taking the time to explain your understanding in this matter. I have nothing against the Louis de Broglie theory, also I am not taken aback by your statement that the pilot wave theory has been proven because you have the freedom to believe it is proven to your own satisfaction.
Like earth’s gravity not affecting our moon but just affecting space which affects the moon, likewise an electron interacting with this pilot wave, a quantum 3-D vibration (3-D+ time?). This just transfers the particle from being the wave to reacting to a wave. This pilot wave theory just adds another layer of complexity. I would not like to be the person arguing that an electron can sense a second slit, or in a practical sense the existence of a second slit is physically influencing pilot waves by its existence. The question remains, what is waving which creates reality.
@@sedevacantist1 I just did an upload vid on this - with more details - you can watch in half speed or go to my blog - thanks ruclips.net/video/1m38Asft-fw/видео.html&feature=emb_logo
طلاب السادس وينكم
that s believable
What is his text book?
The required text for the course is: Griffiths, David J. Introduction to Quantum Mechanics. Pearson Prentice Hall, 2004. ISBN: 9780131118928. See ocw.mit.edu/8-04S16 for more readings and materials. Best wishes on your studies!
de Broglie is pronounced 'de Broy'.
'de Brog-ly' just hurts my ears.
Particles such thing don't exist
Trying to say that an alternating current in a straight wire that creates a varying electromagnetic field that propogates outward is a photon seems ridiculous. Calling the Xray frequency electromagnetic waves created by the free electron laser photons seems equally ridiculous.
you know not - please read: nsb.wikidot.com/pl-9-8-2-1
awesome lectures, but please somebody teach that poor man the pronunciation of "de Broglie"... x)
jasimine b. mostly the word probability 😂...
doesnt matter
@@anjuscafe9796 I learned to pronounce "assholes" just to say it to you.
Imagine with me he isn't the only who pronouns the name in this way ... I discovered that in the comments ... my teacher also says de Broglie with R 😄
@@pocojoyo burnnnn😆😆
Russian 🇷🇺
?