If someone has a really hard time explaining something. It might just be because they don’t actually understand it, and they are trying to figure it out as they go. Often I think I understand something... then I am asked to explain it.
An even better analogy is this: why is North the Arctic, and not Antarctica? Why is Australia not at the top of maps, but on the bottom? The answer is - it doesn't matter.
Let the guy off people, it is hard enough to explain gauge symmetry to an undergraduate in their final year, let alone anybody with no physics background.
@@abd6169 Begin by imagining that at every point in spacetime there is a circle affixed with it... it shoots off in some direction that you can't really determine, but can still imagine there is that circle attached to each point. Now imagine all those circles are rotating through a determined angle, it then becomes clear that the nature of space will not change, consisting of all the circles and the underlying spacetime, that we've imagined. It's clear that any observation will seem synonomous. But all of the circles will have been rotated through a fixed angle So we now have a space with a global symmetry, the rotational symmetry of the circle above spacetime .... If a charged scalar field is allowed to exist on the underlying spacetime, which transforms by a certain phase when the circles are rotated through any given angle, include only pairings of that charged scalar field to itself that are invariant under the phase change, then we can correlate a maintained current with this global rotation symmetry, and we could construct from that current a maintained charge. In a gauge theory, one would promote the global symmetry to a local symmetry instead - so we would still have circles above each point in spacetime, but allow each circle at every different point above the spacetime to be rotated through a different angle, but an angle that changes evenly from point to point and in a way that we can say how that angle is varying between different nearby regions. The charged scalar field will still pick up a phase related to the rotational angle of the circle, but this phase is different at each point in spacetime. It would then turn out that we can describe that rotation angle by means of one of these 'gauge fields', which just lets us transfer the charged scalar field from one point in spacetime to another, always considering how the rotation angle of the circle is changing. That's the basic principles of the idea... . With the "gauge" as a kind of coordinate system that varies depending on the location with respect to some underlying space.
@@michaelfarrell4824 Wait, so global symmetry and gauge theory can both be described by a phase shifting scalar field whose shift is defined by a rotation of a bunch of spheres that are defined at different points in spacetime, and global symmetry is when the function that determines the rotation of each of the spheres is defined as a constant, whereas gauge theory is when the function is defined as any continuous function of spacetime? I'm a math undergrad, so I don't see how any of this has to do with physics (What do the spheres represent? What does the phase shifted scalar field represent? What do you mean by "circle that shoots off in some direction that you can't really determine" and what is that supposed to represent?) but the visualisation itself sounds pretty easy to grasp. I've been messing around with Manim and I'm pretty sure I could whip up an animation of this if you gave me enough time (I probably won't since I got assignments to do). Also, how're we supposed to imagine spacetime? I've been imagining it as a 2d plane with each axis representing a point of space and time, but I've been told to imagine it as a coloured 3d space with each (x,y,z) coord representing a different point in space and each colour representing different points in time. I'm fine with assuming that spacetime can be imagined as 2d plane, but I don't see how you can transform a point in 3 dimensions (the x,y,z coords in the coloured space) to a point in 1 dimension (the space axis on the 2d plane) without compromising a layman's ability to understand it.
Everyone knows a battery has a positive (+) and a negative (-) terminal. Gauge symmetry is the statement that the potential of each terminal is not physical, only the potential difference is physical. That is, we can arbitrarily assign a voltage to the battery terminals, as long as the potential difference is the same. A battery with 9v and 0v on the positive and negative terminals is physically equivalent to a battery with 4.5 on the positive and -4.5 on the negative. The difference in both cases is the same, 9V. So when we go to the store we simply ask for a 9V battery, without mentioning the potential of either terminal. The potential difference is what determines the electric field and the movement of charges across an electrical wire. There are many reasons why in physics we work with potentials and not potential differences. One reason is that it is a mathematical trick to solve differential equations (e.g. Maxwell equations).
Best explanation, what i do not undestand is what does it mean a change of phase in wave equation, i mean psycally. It is said that locally the phase of a electron can change but what does it mean physically . Sorry for my english 🙏
@@elizabethreyna8354 When I wrote that comment I was thinking about classical electromagnetism. In quantum physics, a vector potential can change the phase of charged particles even when the electric and magnetic fields are zero, and in such a way that if each of these particles gets a different phase they will create an interference pattern when they are observed. It is a real effect known as the Aharonov-Bohm effevt.
@@elizabethreyna8354 Copy&paste from ChatGPT There have been several experiments that have demonstrated the Aharonov-Bohm effect. One of the earliest and most well-known experiments was performed by Yakir Aharonov and David Bohm in the early 1950s. In their experiment, Aharonov and Bohm used an apparatus consisting of a solenoid (a coil of wire) with a small opening at each end, and two paths that led around the solenoid. They sent a beam of electrons through the two paths, one on either side of the solenoid, and observed the interference pattern that resulted when the two paths were recombined. What they found was that even though the electrons never passed through the magnetic field of the solenoid itself, the interference pattern was still affected by the magnetic field. This interference pattern was dependent on the presence of the solenoid and the magnetic field it generated, indicating that the electrons were being influenced by the vector potential of the magnetic field. Since then, many other experiments have been conducted to demonstrate the Aharonov-Bohm effect, including experiments with other types of particles such as neutrons, and with more complex geometries. These experiments have confirmed the predictions of quantum theory regarding the influence of vector potentials on charged particles, and have furthered our understanding of the fundamental nature of electromagnetic interactions.
@@orbifold4387 tha is what i want to undeerstand, what does it means "different phase", does it mean that the electron change from positive to negative particule, ?
@@elizabethreyna8354 Imagine an electron moving between two points A and B. In classical mechanics, the electron would move along a fixed, unique trajectory determined by the equations of motion (Newton's laws). In quantum mechanics, there is no fixed trajectory. An electron will take all possible paths between A and B. To compute the wave function of the electron one has to sum over all possible paths with a coefficient (weight) that is a complex number. This coefficient is called a "phase". It is just a complex number that tells you how much the partial wave function along a path contributes to the total wave function.
This is why I love Joe's podcast. So wide-reaching and random. I can tune in to listen to why Connor got his ass beat one day and the next, find out about gauge symmetry and how it applies to our lives. Such an accomplished guy and well deserving of the status he's achieved. Don't know him.. Will probably never meet him but proud and enamoured of his achievements and intellect. Thanks buddy.
Comments here are hilarious! Understanding that labels given to a function are arbitrary was just the 1st step into understanding Gauge Symmetry. He is basically saying you need to grasp this concept in order to get into gauge symmetry. The fact that people think thats all that gauge symmetry is and now think they can explain it better than the physicist is HILARIOUS!!!
The best analogy I know to explain this concept is as follows: You don’t INVENT mathematics, you discover them. The speed of light will always stay the same, 2+2 will always = 4, the square root of 9 will always be 3, e will always = mc^2. However, you do invent the symbols you use to represent these constants. 2 could be changed to II such as in Roman numerals and then it is still true that II + II = IV. The language and units and method of expression is invented, whereas the thing those languages and symbols express is discovered. The discovery does not change based on the way it is described. 100kg and 220 pounds weigh the same whether you call it the former or the latter. And if you go more complicated, this means you can always change the symbols to a new system, and as long as it is balanced and has a conversion for all symbols, it will keep the constant the same. if two people look at something green, person a) May see it as I know “red”, and person b) might see it as I know “blue”, but because we all know that trees are CALLED green, our experience of the constant may all be different in our perception, but it doesn’t change the fact that that tree will always be able to be described by all of us as green and we will mutually understand this, as long as our other colour perception corresponds in a symmetrical manner.
Great takeaway, but yea, Gauge symmetry is something completely different. After hearing his explanation, I don't blame you for interpreting it like this though. I must also add that everything you state is entirely correct; it just isn't gauge symmetry
In military electronics schools, it is taught that current flows from negative to positive. In the civilian schools, it is taught that current flows from positive to negative. It doesn't matter which way you think current is flowing, it all works the same. That's the symmetry of electronics.
Reading the book and got to this chapter, watched this to hear him describe it and it helped. Those in the comments saying he described it in the first 5 mins are wrong, that's symmetry, not gauge symmetry, which is different and he did well to describe it at the end
everyone says he's shit at explaining but he explained it clearly enough.. 2 minutes in.. definitions/names are arbitrary, calling electrons "positively" or "negatively" charged doesn't change their physical properties. where's the fucking problem
I always take Gauge symmetry as a mathematical way to explain that there is something much more fundamental about the universe that we do not understand. Things such as spacetime (gravity) and electromagnetism may be emergent from something deeper but simpler. Our concept of fields is a sign that we are groping an elephant in a dark room. We use them to model the elephant with math but only see a small part of the whole, making for a convoluted idea of what we are actually exploring. That may be why our ideas are so complex and confused. Of course the argument is that our human condition may stand in our way of understanding, that nature does not have to make sense to us and math is the language to unlocking truths about our universe. That begs the question as to whether math is anything more than a human construct modeling what we experience....almost a quasi-religious state if you think about it....Lol, I know I thought math homework was child abuse when I was 12 years old.....
Hes saying the things we thought were important, like the forces, charges etc are all interchangeable and unimportant players in a game, while the fundamental interactions (gravity, em, strong/weak nuclear) are the rules of the game. But below even that there is a supersymmetry, the ultimate symmetry that shows us the arena that this game is played on. The arena determines the rules (gravity...) which determines the players actions (momentum...), so knowing the arena or being able to change it could let us change fundamental interactions.
what? where? why didn't he just say that then? all he was saying was that us observing things and naming them doesn't change their behavior, Wich is obvious
I think the key idea here is extraordinarily deep and much more than about terminology. I think its much more about a hierarchy of properties. Some properties are more permanent/fundamental then others. The property of humans needing to eat is more fundamental (i.e. symmetric or invariant) then the property of humans liking to eat a burger, salad, or a fish. One could explain that a person eats a burger because they like burgers, and a person eats a fish because they like fish. But you could explain all human consumption simultaneously with the more abstract, fundamental, invariant, and symmetric property of humans needing to eat. The checkerboard colors are actually different. They are not just different names. But you could switch all the colors and the game is the same (this was a good analogy). Another way to think of it is that in an empty infinite (or 4 dimensional spherical) universe you can have different points in space. Two points 5 meters away from each other in this universe are different points. But in another way they are also not really different points cuz one point doesn't have any real physical properties more special or different than the other point. There is a symmetry of position. Anywhere you are might as well be anywhere else. Physics isn't always difficult because of its complexity but rather due to its abstractness. I think this is one of those cases where its a topic very challenging to explain on the spot
Concepts he touched on: Lagrangians, Hamiltonians, calculus of variations, spacetime manifolds, particle physics, Maxwell's equations, equivalence, special and general relativity, symmetry, conservation, closed systems, Lorentz transformations,... Pretty much all of physics. Even chaotic systems at the end. He switched from how to why to how again. And did it a thousand times better than I would have. At some point I would have just said, "It helps us with the math and gives us a deeper understanding of all of physics."
What he’s describing is reification. He’s really struggling to overcomplicate a very simple premise. A rose by any other name would smell as sweet. I see a lot of public science advocates struggle to overcomplicate things like this.
I have heard both him and the director of the planetarium discuss the difference between reference and referent. Obviously this is a philosophical problem, they call it type/token hypothesis which is a functionalist theory of mind. The problem and benefit of this idea is that excludes qualia, by that, philosophers mean the quality of greenness, or say a color, or a feeling. The quality of sensory experience. This theory is based on a the preference for objectivity in description of nature - what is, is determined by how it works not by how we understand it through our terms or even metric base. But that does not mean labels are useless, but their meanings are found in their use.
I think he is talking about changing certain variables in a function (e.g. laws of electromagnetism) and how no change will occur in the output. This happens because the function already takes into account these changes, and acts like a self-correcting steering wheel. In the end, the variables become irrelevant as they do not contribute anything to the output of the function. I would love to hear from anyone who knows more on this subject to correct me. I could be completely wrong.
We can experimentally derive laws of physics like momentum, OR we can find the symmetries and the math falls out. It's a double-check, or a way of finding laws that are hard to configure experiments for, or a way to hypothesize new laws.
I remember, once I was in Rome, I asked a guy the shortest way to the next street corner... and he explained it just the way Krauss explained Gauge symmetry to Rogan.
I have no background in physics but I felt like I understood this concept pretty easily for some reason (with many 5 second rewinds to clarify I heard right), but this makes me wonder if I even understood it at all correctly if it's some advanced form of physics lolol. I am a musician, but some parts of this reminded me of concepts in music theory so it made it easy to follow. I don't know, maybe I got it and maybe I didn't, I have no idea. But I feel like I did lmfao
JRE is very educational! I am a dummy, and have been trying to get this concept for years. Any references or ideas on the subject would be greatly appreciated! Thank you! So... might I understand correctly that we could reverse the functions of the positive and negative current flows in our electricity? But we do it this way for convenience, due to the Earth’s charge. And a meter on Earth and a meter on Mars are different “locally”, because of gravity and what not, but the same “globally” because, of gauge symmetry? Globally they are different length tools? Locally they serve the same function? Or reverse that I thick... but am I at all getting this? It doesn’t feel like I get it.
I think what he’s saying is that (like in the movie interstellar) if time is being sped up from you perspective time feels the same for the people in a sed up time.
He blew his own argument with the chess analogy. The changing of the colors of the pieces would give the formerly black pieces the advantage of going first for once, and increase the probability of winning with those those particular pieces, as they were at a disadvantage when they were black.
To make the explanation interesting and universal he was required to expand the explanation to examples that exhibit symmetry under the rules of the system. People who are complaining that he took too long to get to a clear explanation aren't following what he is saying close enough. To explain a concept of a mathematical foundation to someone without the required mathematical background requires an explanation of examples familiar to the individual learning the concept.
The forces of the universe work in such a way that you can define arbitrary measurements, which can be used to derive unique formulas, which can be applied to answer the same questions as our current set of formulas, that are based on our accepted familiar measurements?
16 minutes and you didn't understood the point. Your comment is like a scientific r/whoosh. You completly missed what he was trying to explain. I would explain it, but I don't have the words for it.
This actually made perfect sense to me and I feel like I 'get it' now. Funny that Eric Weinstein said that THIS was the confusing explanation to Joe Rogan and that his was better, because I had no understanding after watching Weinstein.
Do you understand fiber bundles though? Idk why he'd talk about fiber bundles to the general public on a podcast but still they are good for describing the redundancies you see in Guage theory.
JoshReflek But he actually wasn't insulting so the sarcasm isn't as funny :/. If you weren't sarcastic then I am deeply sorry and want to apologize for misunderstanding you.
It's not about sematic....If the universe treat positively charged and negatively charged non symmetrically, then positive and negative are still labels....but the symmetry will not exist (similarly if the rule for black and white are different in chess...black and white are still labels, but they are not symmetric). So it's not just about semantic...it's about the symmetry of the universe.
it's pretty simple. the electromagnetic field is what matters...more so than the particles being influenced by the field. Different people shop in malls from a day to day basis...however, the mall remains unchanged by who is there each day.
Let me see if I’ve got this. It reminds of electrical wiring inside a home. You can swap positive and neutral without issue if you wire the entire house that way, but if you mess up, something blows up. This doesn’t change the way the neighborhood or the city or the country wire their homes, the rule is local to that one home.
Are you saying our measurement devices will represent the same values in different environments even though they aren’t the same? Will a yardstick on a larger or smaller planet be bigger or smaller because of how gravity and space time are related?
@@D1sc0rd- No, I have very little knowledge of physics and shit but as long as you listen to what he says it's pretty easy to get what he is talking about the first time. Weirdly enough I've had this thought separately that language and our definitions are irrelevant but I thought everyone knew this. I'm glad I watched this though because now I know what to call shit like that.
Basically what he is implying is what we might have seen on episodes of Star Trek, that the laws of physics might work differently in other parts of the universe.
he could have just said the origin, reference or scale doesn't matter nature will remain the same. Accuracy and repeatability of the measurements are what makes the difference. polarity doesn't matter in the reference only definition of that reference.
I think I get it. Its like, in simple terms, take a glass of water and use your right hand to drink it then place back on the table. Now, use your left hand to take the glass of water and drink it. See, it's that simple.
I think what Lawrence is trying to say is that no matter what human biases we add to the equation (arbitrary terms,names,systems,emotions....),nature still adds up to the same sum(it is what it is,independent of us or our narrow and biased perspective). In other words it is a fool proof way to know when they(physicists)have it right.
I think Lawrence Kraus forgot to mention that If he changed electron’s charge from negative to positive nothing would change. Or maybe it doesn’t matter if he mentioned that because nothing changed anyway.
Man!!... is like you are all driving formula cars and I'm trying to catch up with a 2015 chevy cavalier ..this sounds so kool but I have so many questions
What I thought the first couple times I heard it, but it's much deeper. Too much buildup, go to 9:05 (basically there's always symmetry somehow in nature no matter what you try to change it seems)
A rose by any other name would smell as sweet rose is the definition sweet smell is the dynamic unchanging rule kinda funny how missed the point was when he mentioned laws of nature and Joe assumed he was talking about animals and plantlife when he (I think) was talking about gravity and electricity, considering his rulebook analogy. maybe thats why everyone calls them a rose?
Hmmm, wonder what a universe where laws of physics are symmetric under acceleration would look like? You could turn the steering wheel sharply and not be thrown against the door.
Weird, at 5:10 I got the feeling that Larry is from the future and Joe is from our time. If you allow that hypothetical it seems like Larry is explaining some very confusing thing to Joe that future people already know and Joe is really trying to grasp it because he feels it's important and his laughing to me means that he's kind of getting it.
this seems so incredibly obvious to me. Of course it doesn't matter what we call positive and negative. if we suddenly changed how we described how gravity worked it wouldn't change anything about the universe. the rules are already set, it doesn't matter what we call them. Not sure why this warranted a discussion.
Still trying to understand his actual point, because there is no way that it's this simple. Your answering your own question. Why would Laurence Krauss tell everyone that words don't change physics? He wouldn't. The point was missed. By you, me, and many other people.
What he's saying is, if suddenly for example the electromagnetic charge of every particle flipped, there would be no way of knowing, because the 'positive' charge is exactly the same as the 'negative' charge. It's not to do with what we label the charges, it's the fact that the things we're labeling could change and we wouldn't be able to tell. Another example is how intense gravity strongly warps space. If you had an object that was exactly 1 meter long on Earth, and then took it to the surface of a neutron star, it would be significantly shorter in length. However, since everything you could have brought with you to compare with the meter stick would have ALSO reduced in length, you wouldn't be able to tell the difference. Then if you left the neutron star and landed back on Earth again, your meter stick would once again be one meter long. A symmetry in physics has to do with how if you change a fundamnetal aspect of a system it is impossible to tell what changed from within that system. If you could step outside the universe and look in, you may discover for example that time is constantly slowing down, and it takes twice as long for things to happen than in did the time previously, etc. Thus a second would start off taking one second, then two, then four, eight, sixteen, etc, from your perspective outside the universe, until eventually trillions of years would need to go by before even one microsecond of time occurred inside the universe. From the perspective of an observer INSIDE the universe, however, time would appear to flow continuously and with no changes.
RothpolX is pretty much correct from my layman understanding of symmetries. Basically, take any system in physics, and if there is a way you can change that system and and the system is identical to what it was before, then you've found a symmetry and that symmetry requires a conservation law in order to exist. A classic example of of this is if you shifted the entire universe ten feet to the left. Nothing changes about the universe if you do this, so we've found a symmetry. This particular symmetry is translational symmetry, and it implies the law of conservation of momentum. The charge symmetry, that the positive and negative charges can be flipped at any time, gives you conservation of charge. Krause went one further, and said the universe has a rulebook that keeps track of what charge does what to what other charge, and that rulebook is the electric and magnetic fields. So then we should be all kinds of fields related to different forces and symmetries and conservation laws, and we do. I dunno if every symmetry has a field, but I know there are at least several of them. Unfortunately, his explanation of all that was rushed and rather jumbled together and pretty hard to follow.
I love how physicists can take a complicated problem, and, using a simple analogy, make it much worse.
If someone has a really hard time explaining something. It might just be because they don’t actually understand it, and they are trying to figure it out as they go. Often I think I understand something... then I am asked to explain it.
This guy is like the Teddy Atlas of science with his analogies
well i guess its all math its like explaining things in french
An even better analogy is this: why is North the Arctic, and not Antarctica? Why is Australia not at the top of maps, but on the bottom?
The answer is - it doesn't matter.
Awww... you heard Weinstein say it was confusing so you came on here to post this comment. Cute
love when joe has scientists on the show
I admire Krauss for attempting to explain gauge symmetry, and, for me, I got something from it. Thank you for putting this on-line.
Let the guy off people, it is hard enough to explain gauge symmetry to an undergraduate in their final year, let alone anybody with no physics background.
Seems pretty simple to me but maybe that's because I'm looking at it simply, often good advice when trying to understand the complicated
@@michaelfarrell4824 teach me if you understand it
@@abd6169 Begin by imagining that at every point in spacetime there is a circle affixed with it... it shoots off in some direction that you can't really determine, but can still imagine there is that circle attached to each point.
Now imagine all those circles are rotating through a determined angle, it then becomes clear that the nature of space will not change, consisting of all the circles and the underlying spacetime, that we've imagined. It's clear that any observation will seem synonomous. But all of the circles will have been rotated through a fixed angle
So we now have a space with a global symmetry, the rotational symmetry of the circle above spacetime
....
If a charged scalar field is allowed to exist on the underlying spacetime, which transforms by a certain phase when the circles are rotated through any given angle, include only pairings of that charged scalar field to itself that are invariant under the phase change,
then we can correlate a maintained current with this global rotation symmetry, and we could construct from that current a maintained charge.
In a gauge theory, one would promote the global symmetry to a local symmetry instead - so we would still have circles above each point in spacetime, but allow each circle at every different point above the spacetime to be rotated through a different angle,
but an angle that changes evenly from point to point and in a way that we can say how that angle is varying between different nearby regions. The charged scalar field will still pick up a phase related to the rotational angle of the circle, but this phase is different at each point in spacetime.
It would then turn out that we can describe that rotation angle by means of one of these 'gauge fields', which just lets us transfer the charged scalar field from one point in spacetime to another, always considering how the rotation angle of the circle is changing.
That's the basic principles of the idea... . With the "gauge" as a kind of coordinate system that varies depending on the location with respect to some underlying space.
@@michaelfarrell4824 Wait, so global symmetry and gauge theory can both be described by a phase shifting scalar field whose shift is defined by a rotation of a bunch of spheres that are defined at different points in spacetime, and global symmetry is when the function that determines the rotation of each of the spheres is defined as a constant, whereas gauge theory is when the function is defined as any continuous function of spacetime?
I'm a math undergrad, so I don't see how any of this has to do with physics (What do the spheres represent? What does the phase shifted scalar field represent? What do you mean by "circle that shoots off in some direction that you can't really determine" and what is that supposed to represent?) but the visualisation itself sounds pretty easy to grasp. I've been messing around with Manim and I'm pretty sure I could whip up an animation of this if you gave me enough time (I probably won't since I got assignments to do).
Also, how're we supposed to imagine spacetime? I've been imagining it as a 2d plane with each axis representing a point of space and time, but I've been told to imagine it as a coloured 3d space with each (x,y,z) coord representing a different point in space and each colour representing different points in time.
I'm fine with assuming that spacetime can be imagined as 2d plane, but I don't see how you can transform a point in 3 dimensions (the x,y,z coords in the coloured space) to a point in 1 dimension (the space axis on the 2d plane) without compromising a layman's ability to understand it.
Notnilc space time is 4D
Everyone knows a battery has a positive (+) and a negative (-) terminal. Gauge symmetry is the statement that the potential of each terminal is not physical, only the potential difference is physical. That is, we can arbitrarily assign a voltage to the battery terminals, as long as the potential difference is the same. A battery with 9v and 0v on the positive and negative terminals is physically equivalent to a battery with 4.5 on the positive and -4.5 on the negative. The difference in both cases is the same, 9V. So when we go to the store we simply ask for a 9V battery, without mentioning the potential of either terminal. The potential difference is what determines the electric field and the movement of charges across an electrical wire. There are many reasons why in physics we work with potentials and not potential differences. One reason is that it is a mathematical trick to solve differential equations (e.g. Maxwell equations).
Best explanation, what i do not undestand is what does it mean a change of phase in wave equation, i mean psycally. It is said that locally the phase of a electron can change but what does it mean physically . Sorry for my english 🙏
@@elizabethreyna8354 When I wrote that comment I was thinking about classical electromagnetism. In quantum physics, a vector potential can change the phase of charged particles even when the electric and magnetic fields are zero, and in such a way that if each of these particles gets a different phase they will create an interference pattern when they are observed. It is a real effect known as the Aharonov-Bohm effevt.
@@elizabethreyna8354 Copy&paste from ChatGPT There have been several experiments that have demonstrated the Aharonov-Bohm effect. One of the earliest and most well-known experiments was performed by Yakir Aharonov and David Bohm in the early 1950s.
In their experiment, Aharonov and Bohm used an apparatus consisting of a solenoid (a coil of wire) with a small opening at each end, and two paths that led around the solenoid. They sent a beam of electrons through the two paths, one on either side of the solenoid, and observed the interference pattern that resulted when the two paths were recombined.
What they found was that even though the electrons never passed through the magnetic field of the solenoid itself, the interference pattern was still affected by the magnetic field. This interference pattern was dependent on the presence of the solenoid and the magnetic field it generated, indicating that the electrons were being influenced by the vector potential of the magnetic field.
Since then, many other experiments have been conducted to demonstrate the Aharonov-Bohm effect, including experiments with other types of particles such as neutrons, and with more complex geometries. These experiments have confirmed the predictions of quantum theory regarding the influence of vector potentials on charged particles, and have furthered our understanding of the fundamental nature of electromagnetic interactions.
@@orbifold4387 tha is what i want to undeerstand, what does it means "different phase", does it mean that the electron change from positive to negative particule, ?
@@elizabethreyna8354 Imagine an electron moving between two points A and B. In classical mechanics, the electron would move along a fixed, unique trajectory determined by the equations of motion (Newton's laws). In quantum mechanics, there is no fixed trajectory. An electron will take all possible paths between A and B. To compute the wave function of the electron one has to sum over all possible paths with a coefficient (weight) that is a complex number. This coefficient is called a "phase". It is just a complex number that tells you how much the partial wave function along a path contributes to the total wave function.
My cat's breath smells like cat food.
Then your cat food also smells like a cat.
@@rickhunter17 cats smelled differently before packaged cat food/
This is why I love Joe's podcast. So wide-reaching and random. I can tune in to listen to why Connor got his ass beat one day and the next, find out about gauge symmetry and how it applies to our lives. Such an accomplished guy and well deserving of the status he's achieved. Don't know him.. Will probably never meet him but proud and enamoured of his achievements and intellect. Thanks buddy.
These comments are the Dunning-Kruger effect at its best.
Let's help each other out. You explain what that effect is, and I will teach you basic grammar.
@@jacobgalloway9123 hahahahaha
** these, its
@@professorboltzmann5709 Thanks.
When u try to be smart
I just drove into a perfectly symmetrical tree.
I find Mr Krauss explanation more understandable than Eric Weinstiens
I think there's less depth though
Comments here are hilarious! Understanding that labels given to a function are arbitrary was just the 1st step into understanding Gauge Symmetry. He is basically saying you need to grasp this concept in order to get into gauge symmetry. The fact that people think thats all that gauge symmetry is and now think they can explain it better than the physicist is HILARIOUS!!!
Thank you. Finally someone with intelligence.
I think I just located intelligent life forms in the UA-cam comment section... sir how did you get here?
I totally understand it and plenty of other areas of science
Labels being arbitrary should be common sense. I wish he didn't spend so much time trying to explain that concept lol
EDTGO1 He is not just saying labels are arbitrary but electrons and protons are interchangeable in Maxwell's equations, right?
The best analogy I know to explain this concept is as follows:
You don’t INVENT mathematics, you discover them. The speed of light will always stay the same, 2+2 will always = 4, the square root of 9 will always be 3, e will always = mc^2. However, you do invent the symbols you use to represent these constants. 2 could be changed to II such as in Roman numerals and then it is still true that II + II = IV. The language and units and method of expression is invented, whereas the thing those languages and symbols express is discovered. The discovery does not change based on the way it is described. 100kg and 220 pounds weigh the same whether you call it the former or the latter. And if you go more complicated, this means you can always change the symbols to a new system, and as long as it is balanced and has a conversion for all symbols, it will keep the constant the same.
if two people look at something green, person a) May see it as I know “red”, and person b) might see it as I know “blue”, but because we all know that trees are CALLED green, our experience of the constant may all be different in our perception, but it doesn’t change the fact that that tree will always be able to be described by all of us as green and we will mutually understand this, as long as our other colour perception corresponds in a symmetrical manner.
That’s not gauge symmetry, that’s just relabelling.
Great takeaway, but yea, Gauge symmetry is something completely different. After hearing his explanation, I don't blame you for interpreting it like this though. I must also add that everything you state is entirely correct; it just isn't gauge symmetry
In military electronics schools, it is taught that current flows from negative to positive. In the civilian schools, it is taught that current flows from positive to negative. It doesn't matter which way you think current is flowing, it all works the same. That's the symmetry of electronics.
It's like where clothes only purpose is to cover u not what kind of shirt or colr
I love how your show is hella random and hella informative THANKS JOE
Reading the book and got to this chapter, watched this to hear him describe it and it helped. Those in the comments saying he described it in the first 5 mins are wrong, that's symmetry, not gauge symmetry, which is different and he did well to describe it at the end
everyone says he's shit at explaining but he explained it clearly enough..
2 minutes in.. definitions/names are arbitrary, calling electrons "positively" or "negatively" charged doesn't change their physical properties.
where's the fucking problem
This is lecture 1 in our series "Lawrence Krauss explains advanced physics concepts that Joe does not have the background to possibly understand."
“If you can't explain it to a six year old, you don't understand it yourself.” Albert Einstein
Now look here You!! Joe did just fine! He said a couple times he didn't understand! You probably love Alex Jones...
@@sheriffakhry9084 I definitely do not agree with that. Science builds up....
Awesome. Explained it so easy.
Lawrence is usually good at explaining things, but here he is paddling around in deep water.
I always take Gauge symmetry as a mathematical way to explain that there is something much more fundamental about the universe that we do not understand. Things such as spacetime (gravity) and electromagnetism may be emergent from something deeper but simpler. Our concept of fields is a sign that we are groping an elephant in a dark room. We use them to model the elephant with math but only see a small part of the whole, making for a convoluted idea of what we are actually exploring. That may be why our ideas are so complex and confused. Of course the argument is that our human condition may stand in our way of understanding, that nature does not have to make sense to us and math is the language to unlocking truths about our universe. That begs the question as to whether math is anything more than a human construct modeling what we experience....almost a quasi-religious state if you think about it....Lol, I know I thought math homework was child abuse when I was 12 years old.....
Hes saying the things we thought were important, like the forces, charges etc are all interchangeable and unimportant players in a game, while the fundamental interactions (gravity, em, strong/weak nuclear) are the rules of the game. But below even that there is a supersymmetry, the ultimate symmetry that shows us the arena that this game is played on. The arena determines the rules (gravity...) which determines the players actions (momentum...), so knowing the arena or being able to change it could let us change fundamental interactions.
This is a perfect summary of what he was trying to say. He just never got the real point of his argument very well.
Isaac Schmitz no... That's not what he was saying
what? where? finally a smart subscriber
what? where? why didn't he just say that then? all he was saying was that us observing things and naming them doesn't change their behavior, Wich is obvious
He sort of did say it, just not in one self-contained analogy. As to why... have you ever done a live broadcast? Theres very little time to think.
Its amazing how Joe is getting that
I think the key idea here is extraordinarily deep and much more than about terminology. I think its much more about a hierarchy of properties. Some properties are more permanent/fundamental then others. The property of humans needing to eat is more fundamental (i.e. symmetric or invariant) then the property of humans liking to eat a burger, salad, or a fish. One could explain that a person eats a burger because they like burgers, and a person eats a fish because they like fish. But you could explain all human consumption simultaneously with the more abstract, fundamental, invariant, and symmetric property of humans needing to eat.
The checkerboard colors are actually different. They are not just different names. But you could switch all the colors and the game is the same (this was a good analogy). Another way to think of it is that in an empty infinite (or 4 dimensional spherical) universe you can have different points in space. Two points 5 meters away from each other in this universe are different points. But in another way they are also not really different points cuz one point doesn't have any real physical properties more special or different than the other point. There is a symmetry of position. Anywhere you are might as well be anywhere else.
Physics isn't always difficult because of its complexity but rather due to its abstractness. I think this is one of those cases where its a topic very challenging to explain on the spot
My brain got toasted
Concepts he touched on: Lagrangians, Hamiltonians, calculus of variations, spacetime manifolds, particle physics, Maxwell's equations, equivalence, special and general relativity, symmetry, conservation, closed systems, Lorentz transformations,... Pretty much all of physics. Even chaotic systems at the end. He switched from how to why to how again. And did it a thousand times better than I would have. At some point I would have just said, "It helps us with the math and gives us a deeper understanding of all of physics."
once he hit the baseball reference, it finally clicked. just try imagine it with a asport! ahahaha
What he’s describing is reification. He’s really struggling to overcomplicate a very simple premise. A rose by any other name would smell as sweet. I see a lot of public science advocates struggle to overcomplicate things like this.
I read his book I just came here to clarify that I comprehended correctly
I have heard both him and the director of the planetarium discuss the difference between reference and referent. Obviously this is a philosophical problem, they call it type/token hypothesis which is a functionalist theory of mind. The problem and benefit of this idea is that excludes qualia, by that, philosophers mean the quality of greenness, or say a color, or a feeling. The quality of sensory experience. This theory is based on a the preference for objectivity in description of nature - what is, is determined by how it works not by how we understand it through our terms or even metric base. But that does not mean labels are useless, but their meanings are found in their use.
He dumbed it down for people like me and it's still over my head.
Lol same
As I was looking up words I thought I knew the definition of I crashed into the only tree for miles.
So he's saying that the qualitative characteristics of the particles are the same, but there are two different "teams" of them in the cosmos?
Why cant I find the full interview only clips
WE GET IT ON THE CHARGE SEMANTICS
It plays out in everytime for all time
I got it when he compared it to turning a sphere
I think he is talking about changing certain variables in a function (e.g. laws of electromagnetism) and how no change will occur in the output. This happens because the function already takes into account these changes, and acts like a self-correcting steering wheel. In the end, the variables become irrelevant as they do not contribute anything to the output of the function. I would love to hear from anyone who knows more on this subject to correct me. I could be completely wrong.
its like an outline drawing; u can paint it different colors but it will always be the same picture every time 😎
What he needed to do was provide one clear example of a scenario in which gauge symmetry is useful.
It's useful in understanding physics
We can experimentally derive laws of physics like momentum, OR we can find the symmetries and the math falls out. It's a double-check, or a way of finding laws that are hard to configure experiments for, or a way to hypothesize new laws.
I remember, once I was in Rome, I asked a guy the shortest way to the next street corner... and he explained it just the way Krauss explained Gauge symmetry to Rogan.
Up is down. Down is up. There you go lmao
Krause is a great teacher ... In this universe... Under the rules of this universe
I was all over the road right when Joe said people are probably driving in to trees right now
We're going back to alchemy, aren't we?
I have no background in physics but I felt like I understood this concept pretty easily for some reason (with many 5 second rewinds to clarify I heard right), but this makes me wonder if I even understood it at all correctly if it's some advanced form of physics lolol. I am a musician, but some parts of this reminded me of concepts in music theory so it made it easy to follow. I don't know, maybe I got it and maybe I didn't, I have no idea. But I feel like I did lmfao
JRE is very educational!
I am a dummy, and have been trying to get this concept for years.
Any references or ideas on the subject would be greatly appreciated!
Thank you!
So... might I understand correctly that we could reverse the functions of the positive and negative current flows in our electricity? But we do it this way for convenience, due to the Earth’s charge.
And a meter on Earth and a meter on Mars are different “locally”, because of gravity and what not, but the same “globally” because, of gauge symmetry?
Globally they are different length tools?
Locally they serve the same function?
Or reverse that I thick... but am I at all getting this? It doesn’t feel like I get it.
Joe is like "oh so the universe is basically a chess board"
I think what he’s saying is that (like in the movie interstellar) if time is being sped up from you perspective time feels the same for the people in a sed up time.
This comment is underrated.
He blew his own argument with the chess analogy. The changing of the colors of the pieces would give the formerly black pieces the advantage of going first for once, and increase the probability of winning with those those particular pieces, as they were at a disadvantage when they were black.
congratulations you just outsmarted a theoretical physicist, give yourself a pat on the back man
To make the explanation interesting and universal he was required to expand the explanation to examples that exhibit symmetry under the rules of the system. People who are complaining that he took too long to get to a clear explanation aren't following what he is saying close enough. To explain a concept of a mathematical foundation to someone without the required mathematical background requires an explanation of examples familiar to the individual learning the concept.
The forces of the universe work in such a way that you can define arbitrary measurements, which can be used to derive unique formulas, which can be applied to answer the same questions as our current set of formulas, that are based on our accepted familiar measurements?
16 minutes, fark me. "A rose by any other name..." done.
He is trying to simplify it in a way that only confuses him :)
16 minutes and you didn't understood the point. Your comment is like a scientific r/whoosh. You completly missed what he was trying to explain. I would explain it, but I don't have the words for it.
yea. totally got it.
As above so as below. Everything makes sense. Everything is extremely connected, but the playing fields are what’s different.
How can I find the full podcast?
Krauss is underated.
This actually made perfect sense to me and I feel like I 'get it' now. Funny that Eric Weinstein said that THIS was the confusing explanation to Joe Rogan and that his was better, because I had no understanding after watching Weinstein.
Do you understand fiber bundles though? Idk why he'd talk about fiber bundles to the general public on a podcast but still they are good for describing the redundancies you see in Guage theory.
"changing labels for things does not change their function"
saved you 16 mins of ramble
That's not what he said, you obviously didn't pay attention
thx for not being insulting while explaining clearly what was missed.
JoshReflek But he actually wasn't insulting so the sarcasm isn't as funny :/. If you weren't sarcastic then I am deeply sorry and want to apologize for misunderstanding you.
I think thats exactly what he said.
JoshReflek yeah I don't get what's so complicated, it seems very obvious that the name for a thing doesn't matter
We are like computer in the sense we take input, we do tick and we give output in space time.
Lumped together universal dymmetry and habit of naming things in physics (spin, color, etc.) Doesn't help, confuses people.
so how did gauge symmetry affect the delineation of physics as the big bang unfolded?
Only a PhD could ramble so much that they make a mathematical statement a semantic problem
It's not about sematic....If the universe treat positively charged and negatively charged non symmetrically, then positive and negative are still labels....but the symmetry will not exist (similarly if the rule for black and white are different in chess...black and white are still labels, but they are not symmetric). So it's not just about semantic...it's about the symmetry of the universe.
Man Krauss really dug himself in
His book is only $5 on Amazon right now
it's pretty simple. the electromagnetic field is what matters...more so than the particles being influenced by the field.
Different people shop in malls from a day to day basis...however, the mall remains unchanged by who is there each day.
Physicists are awesome people a lot of the time
Let me see if I’ve got this. It reminds of electrical wiring inside a home. You can swap positive and neutral without issue if you wire the entire house that way, but if you mess up, something blows up. This doesn’t change the way the neighborhood or the city or the country wire their homes, the rule is local to that one home.
Are you saying our measurement devices will represent the same values in different environments even though they aren’t the same? Will a yardstick on a larger or smaller planet be bigger or smaller because of how gravity and space time are related?
Lightning strikes from the ground up, how about that.
So could there be other universes with different symmetries or if not would there then need to be a supersymmetry of those universes?
I get it. That's brilliant
What book is he referring to? One he wrote.
Shit is on a loop
Joe's being nice.
Repeated himself for 15 minutes what he successfully explained within 4 mins
Bob West not everyone is a super genius who got hired as vice chairman to tesla like you
@@D1sc0rd- No, I have very little knowledge of physics and shit but as long as you listen to what he says it's pretty easy to get what he is talking about the first time.
Weirdly enough I've had this thought separately that language and our definitions are irrelevant but I thought everyone knew this. I'm glad I watched this though because now I know what to call shit like that.
Exactly
RENILO You haven’t actually understood what gauge symmetry is then, as what you’re talking about is just relabelling.
Basically what he is implying is what we might have seen on episodes of Star Trek, that the laws of physics might work differently in other parts of the universe.
he could have just said
the origin, reference or scale doesn't matter nature will remain the same. Accuracy and repeatability of the measurements are what makes the difference. polarity doesn't matter in the reference only definition of that reference.
..." the more we change things....the more they stay the same" /...lol
Just a name like gravity
Basically we know something exists based off the properties or function of other things?
I think I get it. Its like, in simple terms, take a glass of water and use your right hand to drink it then place back on the table. Now, use your left hand to take the glass of water and drink it. See, it's that simple.
Brevity is the soul of wit
I think what Lawrence is trying to say is that no matter what human biases we add to the equation (arbitrary terms,names,systems,emotions....),nature still adds up to the same sum(it is what it is,independent of us or our narrow and biased perspective). In other words it is a fool proof way to know when they(physicists)have it right.
Lawrence: *explains physics for 10 minutes*
Joe: Do you study ecosystems?
Can we answer how any of it is possible? Where did anything come from?
I think Lawrence Kraus forgot to mention that If he changed electron’s charge from negative to positive nothing would change. Or maybe it doesn’t matter if he mentioned that because nothing changed anyway.
Man!!... is like you are all driving formula cars and I'm trying to catch up with a 2015 chevy cavalier ..this sounds so kool but I have so many questions
Joe "I'm too high for this shit" Rogan.
Nothing chages but the name.
What conclusion did you come up with?
What I thought the first couple times I heard it, but it's much deeper. Too much buildup, go to 9:05 (basically there's always symmetry somehow in nature no matter what you try to change it seems)
A rose by any other name would smell as sweet
rose is the definition
sweet smell is the dynamic unchanging rule
kinda funny how missed the point was when he mentioned laws of nature and Joe assumed he was talking about animals and plantlife when he (I think) was talking about gravity and electricity, considering his rulebook analogy.
maybe thats why everyone calls them a rose?
In chess Queen takes color, so changing the colors of the squares would reverse the order of the king and queen on the back rank.
Andrew Bellinger that’s why he also mentioned that the board would need to be rotated 90°.watch that part again
electro is based on feild
A rose by any other name.
it's all interoperation.
Pretty sure that the first person to label the charge of an electron as "negative" already knew that it was an arbitrary choice.
Hmmm, wonder what a universe where laws of physics are symmetric under acceleration would look like? You could turn the steering wheel sharply and not be thrown against the door.
Weird, at 5:10 I got the feeling that Larry is from the future and Joe is from our time. If you allow that hypothetical it seems like Larry is explaining some very confusing thing to Joe that future people already know and Joe is really trying to grasp it because he feels it's important and his laughing to me means that he's kind of getting it.
so we should aim to be on the outside who we are on the inside.
Mind blown emoji
this seems so incredibly obvious to me. Of course it doesn't matter what we call positive and negative. if we suddenly changed how we described how gravity worked it wouldn't change anything about the universe. the rules are already set, it doesn't matter what we call them. Not sure why this warranted a discussion.
Still trying to understand his actual point, because there is no way that it's this simple. Your answering your own question. Why would Laurence Krauss tell everyone that words don't change physics? He wouldn't. The point was missed. By you, me, and many other people.
What he's saying is, if suddenly for example the electromagnetic charge of every particle flipped, there would be no way of knowing, because the 'positive' charge is exactly the same as the 'negative' charge. It's not to do with what we label the charges, it's the fact that the things we're labeling could change and we wouldn't be able to tell.
Another example is how intense gravity strongly warps space. If you had an object that was exactly 1 meter long on Earth, and then took it to the surface of a neutron star, it would be significantly shorter in length. However, since everything you could have brought with you to compare with the meter stick would have ALSO reduced in length, you wouldn't be able to tell the difference. Then if you left the neutron star and landed back on Earth again, your meter stick would once again be one meter long.
A symmetry in physics has to do with how if you change a fundamnetal aspect of a system it is impossible to tell what changed from within that system. If you could step outside the universe and look in, you may discover for example that time is constantly slowing down, and it takes twice as long for things to happen than in did the time previously, etc. Thus a second would start off taking one second, then two, then four, eight, sixteen, etc, from your perspective outside the universe, until eventually trillions of years would need to go by before even one microsecond of time occurred inside the universe. From the perspective of an observer INSIDE the universe, however, time would appear to flow continuously and with no changes.
Rothpol X thanks for clarifying, he didn't explain it that well.
Rothpol X If this is a correct explanation of gauge symmetry you've done a fantastic job of clarifying it in my dumb mind, thank you.
RothpolX is pretty much correct from my layman understanding of symmetries. Basically, take any system in physics, and if there is a way you can change that system and and the system is identical to what it was before, then you've found a symmetry and that symmetry requires a conservation law in order to exist.
A classic example of of this is if you shifted the entire universe ten feet to the left. Nothing changes about the universe if you do this, so we've found a symmetry. This particular symmetry is translational symmetry, and it implies the law of conservation of momentum.
The charge symmetry, that the positive and negative charges can be flipped at any time, gives you conservation of charge.
Krause went one further, and said the universe has a rulebook that keeps track of what charge does what to what other charge, and that rulebook is the electric and magnetic fields. So then we should be all kinds of fields related to different forces and symmetries and conservation laws, and we do. I dunno if every symmetry has a field, but I know there are at least several of them.
Unfortunately, his explanation of all that was rushed and rather jumbled together and pretty hard to follow.