I strongly suggest that anyone interested in Feynman Diagrams reads Feynman's book "QED: the strange theory of light and matter". Heck, I suggest that you read it even if your not interested in Feynman Diagrams, it's a fantastic book.
Perry Turner I second that. What a brilliant and suprisingly small book. Leaves you feeling alike a genius (until you try to explain it to someone else lol). You certainly learn a lot about the seemingly impenetrable topic of light and photons.
The man at 0:25 is an excellent communicator. His voice is so calming and clear, and his face is so kind and empathetic. He gives off an auroa of safety and intellect which I love. Extremely attractive and a great quality to have.
+Logan Retamoza I completely agree. His name's Ed Copeland, which is usually mentioned in the video descriptions but isn't in this one, for some reason.
Awesome tabletop diagrams! I love Feynman diagrams; they make me feel like I can almost understand what's going on. The videos of Feynman's Auckland lectures in which he explains and demonstrates them are not to be missed!
I remember learning of Feynman diagrams from a documentary about six years ago on his life and teachings. What a fantastic man, with an amazing mind and a true, raw passion for science.
+Popo Le'Atheist His main element of genius was his angle of reference. He saw things in a very different way. Check out their video of Feynmann's Safe cracking.
I love the honesty of the first person in the video saying that he could not fully understand it... Only great men have the perspective of their standing!!!
A lot of physics feels like something you could work out if you really tried. Then there is Feynman diagrams. I don't think I'd be able to come up with something like this if I thought about it for a million years
Yeah, like you could come up with relativity, or even Newtonian gravity. Those unique thoughts are only reserved for the most brilliant ones, and trust me, if you are commenting that here you are not one of them.
Can i just say, yes you are! You've helped so many people love physics, given even more a great understanding of it, and given people hours of entertainment. If i could, i'd name an element after you.
Wonderful one of my favourites. Feynman has always been my physics hero and have read a lot of books about him and by him, also some amazing lectures he did in New Zealand. For anyone struggling with these concepts i would recommend the New Zealand lectures and the book Genius by James Gleick, the lectures by Feynman because they are derived from his thoughts and Genius because it puts these ideas and the roots of quantum mechanics in context, showing the evolution of his ideas and others. It can be very difficult to understand without a context in my opinion.
The first time I was introduced to Feynman Diagrams 40 years ago, I was blown away. One particular diagram caught me by surprise.It describe a particle and an anti-particle producing a photon which emitted an electron. Now that I vaguely understand virtual particles and vacuum quantum fields and the Higgs fields, I can understand why I was surprised, how original his diagrams were. I have no doubt that his diagrams will be key to understand the mysteries of not only dark matter and dark energy, but an unified theory.
Feynman's way of simplifying complex things. was incredible! I listened to "The Feynman Lectures on Physics" as a 15-year old, and I had no problem understanding everything
Frank R. Haugen Professors generally do explain things in an easy to understand way. That's how they became professors. They know the subject so well, that they can leave out the less important bits and give you the gist of it, and the gist is accurate and simple. If someone didn't understand the whole thing, they would maybe need to include the entirety of a complex subsystem in their explanation, because they don't understand the basic input and output of that system. I.e. if you want to explain string concatenation, you could say 1. This function takes two strings and returns a single string consisting of the two in sequence. or 2. The concatenation function takes an input of two strings, and it creates a new string in memory the size of the combined length of the two input strings, where it first inserts the first string at position 0, and then inserts the second string at the position just after the first string. It then presents this data as a single string. They are both correct, but one of them is easy to understand for its purpose. The other one is only necessary to know about if you do any work near the same level of detail, for instance you need to know how much memory the string concatenation uses.
In Feynman's view of quantum mechanics particles can move forward and backwards in time. Those that move forward are particles; those that move backwards are their antiparticles with all the opposite attributes: an electron has a negative charge and an electron number of 1, its antiparticle has a postiive charge and an electron number of -1.
If anyone needs some more technical details about the diagram, without drowning in them, i suggest Prof. Susskind's lecture on string theory and also the lecture about higgs boson. But for a smooth survey this video is just great. thanks for sharing.
I learned how to do Feynman Diagrams in high school... feels melancholy though, as the physics is ridiculously interesting, yet the ideas are devilishly complex. Damned IB HL Physics.
A particle is an excitation of its own field, a photon can jump into existence because the energy in the interaction between the particles generated enough energy to excite the electromagnetic field. This is why light bulbs or fluorescent tubes can generate light from just running electricity through it. Different fields have different energy requirements in order to cause particles to pop into existence, and this is kinda why particle colliders have to get increasingly more powerful.
A nice thing about FDs is that you can read them any other way. If you reverse the time scale a positron is an electron going back in time, for instance.
Feynman Diagrams come from the Interaction Lagrangian for Quantum Field Theory. The Dirac Lagrangian density is first made Imaginary using the Hermitian Conjugate Operator. From there we get the standard Hamiltonian Density and using the S-matrix we can do a the Wick Expansion to get the propogation terms that satisfies the initial particle state the best. the Feynman Diagram is then in correspondence with the term selected, and then use the Feynman Rules to compute the Probability Amplitude.
Whats funny is that this video was published in June of 2010... The Higgs boson was discovered on 4 July 2012 - 2 years later! Feynman's Diagrams were used to express its existence!
The force is 'apparently' continuous but actually it's actually a discrete force. The image that I carry is the "pig pen" electron is continuously emitting and reabsorbing photons as it moves along. The closer it approaches another electron, the higher the probability that a photon will be exchanged.
Sometimes the photon decays back into an electron-positron pair, but their attraction means their velocities are reduced as they move apart. This energy is emitted as a lower-energy photon. Apart from that, the electron-electron repulsion diagram is the electron-positron collision diagram turned sideways. In this sense, a positron is an electron moving backwards in time!
@puncheex, I might be wrong, but I think that in addition to diagrams discussed here, where particles move forward in time, there are diagrams where some partcles move back in time, coming from the future and moving into the past. I belive this has something to do with the difficulties of accepting the diagrams. Right now, the accepted opinion is that particles don't move backwards in time, but behave "as if" they do.
that diagram is of a slightly different notation to what the guy demonstrates on the table. Time runs from left to right. The interaction is in the middle. Since the positron (e+) is an anti particle, it is by convention drawn with the arrow going backwards in time. Same goes for the anti-quark on the right. This is because charge must be a conserved quantity, and the photon is not a charge carrying boson, so the -1 charge from the electron must leave via the positron, using the reverse arrow.
Antiparticles are positive energy solutions, and they are obtained by acting with charge conjugation operator on the negative-energy solutions. So, antiparticles move forward in time, as usual particles.
there are various rules which need to be conserved, it's similar to momentum in that the production of a muon and antimuon, charge will be conserved (both will be 0 or both will be +1 -1) and the 'lepton' number (amount of 'electron-esque' molecules) will be conserved at +1 -1 being 0, producing two baryons of +1 -1 conserving the baryon number sorry if you don't understand that, it's the best I can do I'm afraid :p
@Kargoneth quantum mechanics is difficult to describe, and if you try, it gets confusing. the thing is that electrons constantly emit virtual photons, and if they dont hit anything they never really come into existence. now when two electrons approach each other, some of these virtual photons will hit something, namely the other electron. now they have a real effect, the electrons now exchange real photons, which carry momentum. so the electrons exchange momentum like in a collision.
I could, but there is not enough space here. Feynman imagined a particle staring at one point in space-time travelling to another point and imagined the particle taking all possible paths between them. For each path he worked out a quantity called the ``action'' , A, and divided it by Plank's constant. From the sum over all paths of exp(iA/hbar) he could work out the probability of an event happening. His approach gives ordinary quantum mechanics as taught to students. But it gives lots more.
@Kargoneth also, the feynman diagram of the collision of two electrons is a simplification. actually its one photon going from one electron to the other, and another photon going in the opposite way. but the mathematics allow the simplification, that exchange of a pair of photons is really equivalent to the horizontal wavy line in the diagram. anyway, the photons really dont need to be clever.
Back when I was in high school - or rather, its equivalent - we did basic quantum mechanics, including QED (and QCD, wave-particle duality, et cetera).
@mcmurder3 unless you're doing it wrong. If a truck destined south is going north, it doesn't matter how fast the truck is going. (infinite plane uniform density)
"The particle is whizzing along in time, but it says 'ooh I don't feel very nice, I feel a bit naked so I'll dress myself' so then we'll have one of those going along there" I never thought I'd learn about science by analogy of a camp subatomic particle
Also note that this diagram can exist with a Zo boson instead of the photon which still conserves charge. I prefer Feynmann's original notation to this one. To get it, flip the whole diagram 90 degrees anti clockwise, and then flip the photon another 90 degrees. You can also (like the guy did on the table) tilt the photon upwards to represent the fact that it is not an instantaneous interaction (travels at speed of light or slower) but this is not important and is up to the individual.
Bowleyium would not sound good, and Rogerium sounds rude. Perhaps Martynium Polyakoffium would be better. I hope to do another 60symbols video this week to entertain and inform you about momentum, or if you prefer an element how about momentumium? Thank you for your kind comments.
Repulsion is an effect which emerges from the diagrams, it isn't assumed going in, or even meaningful when creating a diagram. The video leaves out many things required to actually use a diagram and come out with some numbers. For instance, the junctions in the diagrams are not really representative of an exact location but are taken to represent all possible locations for that junction, which is everywhere and every time. However, some locations and times are far more probable than others.
I had a professor who is a bit like that, when ever I asked him about any new findings in physics he says I'm too old to understand (or I'm retired) it's your turn to explain to me :)
@djd904 Photons have zero rest mass. However, they do have energy. And energy and mass are essentially the same thing. So if an electron emits a photon it losses some energy and therefore it losses some mass.
"Do you have any Idea what would cause a particle to emit a cloud of photons? " It's a consequence of the uncertainty principle. You can never determine a particle's kinetic energy with 100% precision, it is always fluctuating. But, due to the conservation of mass/energy total mass/energy must remain the same. That means for each downward fluctuation in the particle's mass/energy it must emit a photon and eventually that photon will collide back with the electron and repay the "energy debt".
Didn't they use Feynman diagram to determine what particles to collide in order to elicit a Higgs boson? (And where to look for it.) Am I understanding that correctly?
@Kargoneth third comment... and if you want to know more about these virtual particles, how long they can exist and how far they can move, you need heisenbergs uncertainty principle. you cannot exactly tell where an electron is, due to heisenbergs uncertainty principle you get a volume where the electron will most likely be, and thats the volume that is filled by those virtual photons surrounding the electron. they cannot violate the principle so they cannot be anywhere else.
Correct me if I'm wrong but there is one technical inaccuracy in saying that antimatter moves back in time. In quantum field theory we get positive energy solutions (usual particles) and negative energy solutions. Negative energy solutions behave as if they were propagating backward in time. But they are not antiparticles, they are just the "negative-energy particles".
@BSZanatsu Rocket engines work by expelling propellant mass at stupendous speed and thus pushing the engine in the opposite direction in accordance with Newton's 3rd law and all that.
If you see the diagram of the Feynmann diagram on wikipedia, an electron annihilates a positron to release a photon which then produces a quark, antiquark and later a gluon. The thing I don't understand is the direction of the arrow on the positron and the anti-quark. Why does it oppose the direction of time? Or does the direction simply indicate the value of the positron (i.e. negative value)? and not the direction of movement.
When the particles come close one another, a photon is emitted, which then pushes the particles apart without them touching; does this mean that light has mass? That light can actually effect something by means of a force?
It depends on the energy of elextron and positron. In the Quantum field theory it can be only one photon but the possibilities are two or more. If they have high kinetic energy they can produce mesons or netrino... (sorry for my english I don't speak this languague very well :/)
Maybe I am not understanding this correctly. Repulsion is a continuous force, that strengthens as two particles get closer. So there cannot simply be one photon in the quantum mechanical process because there needs to be an acceleration, not just an impulse at a certain distance. Is there a near infinite stream of "photons" being emitted at all times, with more hitting as they get closer?
BTW, I was trying to understand relativity, if we think the movement of particle in 2 dimensions(1 for time) at speed of C and C is the limit speed we accept that, when particle starts moving on space dimension, it have to lose speed in time dimension to keep the length total vector of space-time movement at C. I still dont get it, I get it mechanically and mathematically, but not intuitively enough.
The diagram at 1:12 seems incorrect (if I understand the concept correctly). Either e- is interacting with q- and resulting in e+, q, etc.; in which case the particle directions are correct, but the representation of time should be vertical, flowing from top to bottom. Or it is representing an electron colliding with an anti-electron, creating energy, resulting the formation of q-, q, etc. Which means time is represented correctly, but e+ and q- need to switch directions (seems most likely).
No, the process you are imaging is a ball beign tossed ? Because it is not that. Just think about the photon as the agent who pass the information about the position of the particles. If the photon was carrying momentum to the other particle the way you thougth, then how could particles wth different atrract each other ?
A wee bit confused with this one, at the start it said when the get close but never collide it moves of equidistant to each other, then on the other breathe it says when they collide it moves this way, if there is no potential then it won't move,if there is potential then it move to the greater potential, flow will only flow if the potential is there, therefore this Therom is liking riding a bike in a ballon in space,are you peddling or is the potential moving the pedals? Wait there is no potential in space is there?
Something thats not mentioned here (and probably for good reason) is that in the electron and positron collision the line drawn for the positron is pointing backwards with regard to the time axis. Ill just leave that fact here to boggle your minds.
I strongly suggest that anyone interested in Feynman Diagrams reads Feynman's book "QED: the strange theory of light and matter". Heck, I suggest that you read it even if your not interested in Feynman Diagrams, it's a fantastic book.
Perry Turner I second that. What a brilliant and suprisingly small book. Leaves you feeling alike a genius (until you try to explain it to someone else lol). You certainly learn a lot about the seemingly impenetrable topic of light and photons.
+Perry Turner
Thanks :)
Will read.
On top of this, the QED lectures from the 70s are on RUclips and are amazing.
somsoc I didn't realize that! Gonna go find those now.
he was a fine man.
Isn't it amazing that humans can study and understand concepts this complex? These videos completely blow me away.
The man at 0:25 is an excellent communicator. His voice is so calming and clear, and his face is so kind and empathetic.
He gives off an auroa of safety and intellect which I love. Extremely attractive and a great quality to have.
+Logan Retamoza I completely agree. His name's Ed Copeland, which is usually mentioned in the video descriptions but isn't in this one, for some reason.
Awesome tabletop diagrams! I love Feynman diagrams; they make me feel like I can almost understand what's going on. The videos of Feynman's Auckland lectures in which he explains and demonstrates them are not to be missed!
I remember learning of Feynman diagrams from a documentary about six years ago on his life and teachings. What a fantastic man, with an amazing mind and a true, raw passion for science.
+Popo Le'Atheist
His main element of genius was his angle of reference. He saw things in a very different way. Check out their video of Feynmann's Safe cracking.
I love the honesty of the first person in the video saying that he could not fully understand it... Only great men have the perspective of their standing!!!
A lot of physics feels like something you could work out if you really tried. Then there is Feynman diagrams. I don't think I'd be able to come up with something like this if I thought about it for a million years
Yeah, like you could come up with relativity, or even Newtonian gravity. Those unique thoughts are only reserved for the most brilliant ones, and trust me, if you are commenting that here you are not one of them.
Can i just say, yes you are! You've helped so many people love physics, given even more a great understanding of it, and given people hours of entertainment. If i could, i'd name an element after you.
Amazing we used these last year of high school. How something complicated can be explained in simple andbeautiful diagrams is amazing!
I am always blown away by the quality of these videos.
why is it even though i don't understand a word, I still find these videos fascinating?
I'm not a physicist, after high-school was afraid of it and because of this lectures I'm addicted to it. Thanks a lot to all who contribute!
np
Wonderful one of my favourites. Feynman has always been my physics hero and have read a lot of books about him and by him, also some amazing lectures he did in New Zealand. For anyone struggling with these concepts i would recommend the New Zealand lectures and the book Genius by James Gleick, the lectures by Feynman because they are derived from his thoughts and Genius because it puts these ideas and the roots of quantum mechanics in context, showing the evolution of his ideas and others. It can be very difficult to understand without a context in my opinion.
i am doing this is AS physics at the moment and this helped me so much, thank you.
The first time I was introduced to Feynman Diagrams 40 years ago, I was blown away. One particular diagram caught me by surprise.It describe a particle and an anti-particle producing a photon which emitted an electron. Now that I vaguely understand virtual particles and vacuum quantum fields and the Higgs fields, I can understand why I was surprised, how original his diagrams were. I have no doubt that his diagrams will be key to understand the mysteries of not only dark matter and dark energy, but an unified theory.
Feynman's way of simplifying complex things. was incredible!
I listened to "The Feynman Lectures on Physics" as a 15-year old, and I had no problem understanding everything
wow, you must be such a genious
Angelo Zamudio I wish. He was a great teacher, and I just curious about physics. The actual mathematics of the physics is beyond me :-(
Frank R. Haugen Professors generally do explain things in an easy to understand way. That's how they became professors. They know the subject so well, that they can leave out the less important bits and give you the gist of it, and the gist is accurate and simple. If someone didn't understand the whole thing, they would maybe need to include the entirety of a complex subsystem in their explanation, because they don't understand the basic input and output of that system.
I.e. if you want to explain string concatenation, you could say
1. This function takes two strings and returns a single string consisting of the two in sequence.
or
2. The concatenation function takes an input of two strings, and it creates a new string in memory the size of the combined length of the two input strings, where it first inserts the first string at position 0, and then inserts the second string at the position just after the first string. It then presents this data as a single string.
They are both correct, but one of them is easy to understand for its purpose. The other one is only necessary to know about if you do any work near the same level of detail, for instance you need to know how much memory the string concatenation uses.
"listened to"? i don't know where you can listen to them because the Feynman Lectures are a book series.
johnx4224 Audio books maybe?
In Feynman's view of quantum mechanics particles can move forward and backwards in time. Those that move forward are particles; those that move backwards are their antiparticles with all the opposite attributes: an electron has a negative charge and an electron number of 1, its antiparticle has a postiive charge and an electron number of -1.
I love these videos, the comments can be just as interesting.
If anyone needs some more technical details about the diagram, without drowning in them, i suggest Prof. Susskind's lecture on string theory and also the lecture about higgs boson. But for a smooth survey this video is just great. thanks for sharing.
I learned how to do Feynman Diagrams in high school... feels melancholy though, as the physics is ridiculously interesting, yet the ideas are devilishly complex. Damned IB HL Physics.
All science is
If you've found a science that is simple then it's probably an arts subject :P
omg im doing IB physics rn!!!
@@xoxoxoxoxoxoxo6921 lol why didnt u do a level
I’m doing topic 7 right now, and I’m actually loving it
I'm suppose to be doing my trig pre-cal homework, and this is what I'm watching :D
Your syntax is exceptional.
A particle is an excitation of its own field, a photon can jump into existence because the energy in the interaction between the particles generated enough energy to excite the electromagnetic field. This is why light bulbs or fluorescent tubes can generate light from just running electricity through it. Different fields have different energy requirements in order to cause particles to pop into existence, and this is kinda why particle colliders have to get increasingly more powerful.
And you were undoubtedly learning more.
A nice thing about FDs is that you can read them any other way. If you reverse the time scale a positron is an electron going back in time, for instance.
Feynman was a magician.... He was the greatest of them all. Salute to him
Feynman Diagrams come from the Interaction Lagrangian for Quantum Field Theory. The Dirac Lagrangian density is first made Imaginary using the Hermitian Conjugate Operator. From there we get the standard Hamiltonian Density and using the S-matrix we can do a the Wick Expansion to get the propogation terms that satisfies the initial particle state the best. the Feynman Diagram is then in correspondence with the term selected, and then use the Feynman Rules to compute the Probability Amplitude.
Whats funny is that this video was published in June of 2010... The Higgs boson was discovered on 4 July 2012
- 2 years later! Feynman's Diagrams were used to express its existence!
The force is 'apparently' continuous but actually it's actually a discrete force.
The image that I carry is the "pig pen" electron is continuously emitting and reabsorbing photons as it moves along. The closer it approaches another electron, the higher the probability that a photon will be exchanged.
That is an exceptional example of a fragment.
I had a hard time understanding this ...
Richard Feynman Surely You're Joking, Mr. Feynman!
That's funny because I'm reading that book now! It's awesome! RayJan Richard Feynman
Nobody understands this.
@@khellil2 amazing!
Sometimes the photon decays back into an electron-positron pair, but their attraction means their velocities are reduced as they move apart. This energy is emitted as a lower-energy photon. Apart from that, the electron-electron repulsion diagram is the electron-positron collision diagram turned sideways. In this sense, a positron is an electron moving backwards in time!
Thank you so much. I am not a scientist. You explained this so well that I understood it.
What an exceptional sentence fragment!
@puncheex, I might be wrong, but I think that in addition to diagrams discussed here, where particles move forward in time, there are diagrams where some partcles move back in time, coming from the future and moving into the past.
I belive this has something to do with the difficulties of accepting the diagrams.
Right now, the accepted opinion is that particles don't move backwards in time, but behave "as if" they do.
that diagram is of a slightly different notation to what the guy demonstrates on the table. Time runs from left to right. The interaction is in the middle. Since the positron (e+) is an anti particle, it is by convention drawn with the arrow going backwards in time. Same goes for the anti-quark on the right. This is because charge must be a conserved quantity, and the photon is not a charge carrying boson, so the -1 charge from the electron must leave via the positron, using the reverse arrow.
I saw Feynman diagramms in my physics book, but there was no explenation what they mean. Not that I'll ever use them but I needed this:D
I like the fact that both professors tried to use ANALOGIES to explain the concept.
YES !! So cool that you posted a video on Feynman Diagrams !!
Is it true that Richard Feynman called it "The Diagram"?
I really love this comment for all of its philosophical glory.
Yes because he didn’t believe in names
That was an exceptional complete sentence.
Antiparticles are positive energy solutions, and they are obtained by acting with charge conjugation operator on the negative-energy solutions. So, antiparticles move forward in time, as usual particles.
Understanding how little you know, it the beginning of true wisdom.
there are various rules which need to be conserved, it's similar to momentum in that the production of a muon and antimuon, charge will be conserved (both will be 0 or both will be +1 -1) and the 'lepton' number (amount of 'electron-esque' molecules) will be conserved at +1 -1 being 0, producing two baryons of +1 -1 conserving the baryon number
sorry if you don't understand that, it's the best I can do I'm afraid :p
@Kargoneth
quantum mechanics is difficult to describe, and if you try, it gets confusing. the thing is that electrons constantly emit virtual photons, and if they dont hit anything they never really come into existence. now when two electrons approach each other, some of these virtual photons will hit something, namely the other electron. now they have a real effect, the electrons now exchange real photons, which carry momentum. so the electrons exchange momentum like in a collision.
It's also learning,but in a much better and fun way.
Being exceptional is an exception, to the exceptionalists
I could, but there is not enough space here.
Feynman imagined a particle staring at one point in space-time travelling to another point and imagined the particle taking all possible paths between them. For each path he worked out a quantity called the ``action'' , A, and divided it by Plank's constant. From the sum over all paths of exp(iA/hbar) he could work out the probability of an event happening. His approach gives ordinary quantum mechanics as taught to students. But it gives lots more.
Feynman was a brilliant man
Great for A-level physics!! Thanks
@meekmoe there is no mistake there. It shows interraction of electron and positron which then produse quarq and antiquarq. Sorry for bad english
@Kargoneth
also, the feynman diagram of the collision of two electrons is a simplification. actually its one photon going from one electron to the other, and another photon going in the opposite way. but the mathematics allow the simplification, that exchange of a pair of photons is really equivalent to the horizontal wavy line in the diagram.
anyway, the photons really dont need to be clever.
Back when I was in high school - or rather, its equivalent - we did basic quantum mechanics, including QED (and QCD, wave-particle duality, et cetera).
I bought richard feynmans lectures on geometrical optics , clever fellow .
@mcmurder3 unless you're doing it wrong. If a truck destined south is going north, it doesn't matter how fast the truck is going. (infinite plane uniform density)
Another great lesson learned from Sixty Symbols, thanks guys!!!
"The particle is whizzing along in time, but it says 'ooh I don't feel very nice, I feel a bit naked so I'll dress myself' so then we'll have one of those going along there"
I never thought I'd learn about science by analogy of a camp subatomic particle
Also note that this diagram can exist with a Zo boson instead of the photon which still conserves charge. I prefer Feynmann's original notation to this one. To get it, flip the whole diagram 90 degrees anti clockwise, and then flip the photon another 90 degrees. You can also (like the guy did on the table) tilt the photon upwards to represent the fact that it is not an instantaneous interaction (travels at speed of light or slower) but this is not important and is up to the individual.
Bowleyium would not sound good, and Rogerium sounds rude. Perhaps Martynium Polyakoffium would be better.
I hope to do another 60symbols video this week to entertain and inform you about momentum, or if you prefer an element how about momentumium?
Thank you for your kind comments.
Feynman was an absolute legend.
A very nice explanation of a difficult concept, well done!
Particles go in, particles go out.
You can't explain that!
vote for the pixiedust party. we will make a whole bunch of shiny new hospitals, and reduce the debt and uh taxes, at the same time, uh somehow.
These must but O'reily's Diagrams
Bread goes in, toast comes out, but where does the bread go?
Felony Videos Ironically, it makes sense :)))
@@FelonyVideos The bread could take many different routes, and we can calculate the probability of those routes.
Feynman...incredible.
Great Introduction!
if periodic table of videos' crew and sixty symbols' crew did a collab video I'm sure it would be EPIC
Repulsion is an effect which emerges from the diagrams, it isn't assumed going in, or even meaningful when creating a diagram.
The video leaves out many things required to actually use a diagram and come out with some numbers. For instance, the junctions in the diagrams are not really representative of an exact location but are taken to represent all possible locations for that junction, which is everywhere and every time. However, some locations and times are far more probable than others.
I had a professor who is a bit like that, when ever I asked him about any new findings in physics he says I'm too old to understand (or I'm retired) it's your turn to explain to me :)
@djd904
Photons have zero rest mass.
However, they do have energy. And energy and mass are essentially the same thing. So if an electron emits a photon it losses some energy and therefore it losses some mass.
Hey, it was one of these things that stumped Sheldon (and Leonard et al) in the PMS vs AA episode of the Big Bang Theory. Fun fun.
2, so that momentum can be conserved. The two photons are of equal energy, and move in opposite directions.
"Do you have any Idea what would cause a particle to emit a cloud of photons? "
It's a consequence of the uncertainty principle.
You can never determine a particle's kinetic energy with 100% precision, it is always fluctuating. But, due to the conservation of mass/energy total mass/energy must remain the same. That means for each downward fluctuation in the particle's mass/energy it must emit a photon and eventually that photon will collide back with the electron and repay the "energy debt".
Didn't they use Feynman diagram to determine what particles to collide in order to elicit a Higgs boson? (And where to look for it.) Am I understanding that correctly?
@Kargoneth
third comment...
and if you want to know more about these virtual particles, how long they can exist and how far they can move, you need heisenbergs uncertainty principle. you cannot exactly tell where an electron is, due to heisenbergs uncertainty principle you get a volume where the electron will most likely be, and thats the volume that is filled by those virtual photons surrounding the electron. they cannot violate the principle so they cannot be anywhere else.
Correct me if I'm wrong but there is one technical inaccuracy in saying that antimatter moves back in time. In quantum field theory we get positive energy solutions (usual particles) and negative energy solutions. Negative energy solutions behave as if they were propagating backward in time. But they are not antiparticles, they are just the "negative-energy particles".
This is so amazingly interesting. I'm hooked.
I would love it if they added one of those "extrmely complicated diagrams" to the video. Wouldl like to see one.
I love this channel. Thank you for posting.
@BSZanatsu Rocket engines work by expelling propellant mass at stupendous speed and thus pushing the engine in the opposite direction in accordance with Newton's 3rd law and all that.
Great visual discription.
This is one of the videos where I feel like I need a full physics class for.
If you see the diagram of the Feynmann diagram on wikipedia, an electron annihilates a positron to release a photon which then produces a quark, antiquark and later a gluon. The thing I don't understand is the direction of the arrow on the positron and the anti-quark. Why does it oppose the direction of time? Or does the direction simply indicate the value of the positron (i.e. negative value)? and not the direction of movement.
When the particles come close one another, a photon is emitted, which then pushes the particles apart without them touching; does this mean that light has mass? That light can actually effect something by means of a force?
Wow! Feynman is great!
It depends on the energy of elextron and positron. In the Quantum field theory it can be only one photon but the possibilities are two or more. If they have high kinetic energy they can produce mesons or netrino... (sorry for my english I don't speak this languague very well :/)
If there were teachers like this when I was in HS I might have wanted to stay around. C'est la vie.
Exceptional observation.
Fantastic! A 50 years old book!
Maybe I am not understanding this correctly. Repulsion is a continuous force, that strengthens as two particles get closer. So there cannot simply be one photon in the quantum mechanical process because there needs to be an acceleration, not just an impulse at a certain distance. Is there a near infinite stream of "photons" being emitted at all times, with more hitting as they get closer?
BTW, I was trying to understand relativity, if we think the movement of particle in 2 dimensions(1 for time) at speed of C and C is the limit speed we accept that, when particle starts moving on space dimension, it have to lose speed in time dimension to keep the length total vector of space-time movement at C. I still dont get it, I get it mechanically and mathematically, but not intuitively enough.
Excellent video. Thank you for making this clear!
The diagram at 1:12 seems incorrect (if I understand the concept correctly). Either e- is interacting with q- and resulting in e+, q, etc.; in which case the particle directions are correct, but the representation of time should be vertical, flowing from top to bottom. Or it is representing an electron colliding with an anti-electron, creating energy, resulting the formation of q-, q, etc. Which means time is represented correctly, but e+ and q- need to switch directions (seems most likely).
No, the process you are imaging is a ball beign tossed ? Because it is not that. Just think about the photon as the agent who pass the information about the position of the particles.
If the photon was carrying momentum to the other particle the way you thougth, then how could particles wth different atrract each other ?
Exceptional Spelling
Excellent video. I really enjoyed this!
Exceptional retort.
+1! I've been waiting for this!
@redone632
A wee bit confused with this one, at the start it said when the get close but never collide it moves of equidistant to each other, then on the other breathe it says when they collide it moves this way, if there is no potential then it won't move,if there is potential then it move to the greater potential, flow will only flow if the potential is there, therefore this Therom is liking riding a bike in a ballon in space,are you peddling or is the potential moving the pedals? Wait there is no potential in space is there?
exceptional observation.
Something thats not mentioned here (and probably for good reason) is that in the electron and positron collision the line drawn for the positron is pointing backwards with regard to the time axis.
Ill just leave that fact here to boggle your minds.