What If Charge is NOT Fundamental?
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- Опубликовано: 15 мар 2022
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If you've studied any physics you know that like charges repel and opposite charges attract. But why? It's as though this thing - electric charge - is as fundamental a property of an object as its mass. It just sort of ... is. Well it turns out if you dig deep enough, the fundamental-ness of charge unravels, and in many things, including mass itself, are unraveled with it.
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7:40 apparently Gell-Mann wasn't aware of group theory until after the fact-he actually worked out the symmetries and accompanying mathematics himself and then had it pointed out to him that what he'd constructed was the SU(3) group, which is honestly even more impressive
What exact aspect held this symmetry though?
that is wild
Episode co-writer here
That's no the first time something like this happened in the history of physics. Heisenberg was unaware of matrices when he developed the matrix interpretation of quantum mechanics. He thought of them like very long and weird vectors
I guess the moral of the story is that we don't know what branches of mathematics are gonna be useful in physics and that forces physicists to discover them on their own sometimes
@@HighlyEntropicMind Long and weird vectors is how I came to understand matrices. It's a kind of accounting trick.
Physicists need to know pure math to enhance their ability to progress in physics.😒
whoever writes these episodes does a great job. i can't imagine how hard it must be to select and sequence information on topics like these in a way that makes sense to people who know very little. and do it in ten minutes . teaching is an underappreciated skill
It is written by a team, including Matt - he ain't just a pretty face, he is a physicist.
Episode co-writer here
First of all, thank you, it is hard but team work makes the dream work. For this particular episode I pitched the idea to the team, I made a draft, then Matt and others read it and found things I had to improve, so I made another draft and then they made comments on that draft and I made a new one until we finally reached a finished product. Finally Matt adapts the script to better fit his stile and the episode is recorded
I second this. These are some seriously complex topics and they are addressed in a very informative way. The thought that goes into how the episodes are ordered is something I appreciate the longer I watch. The series started relatively (no pun intended) simplistic, dealing with the basics of GR and SR at levels a beginner could understand, but over time have assembled a deep enough well that even some fairly technical stuff like this can be processed by someone like me who has never taken a physics class.
@@HighlyEntropicMind thank u!
it's not that hard if you understand it, and can think step by step. just write the step by step and revise, revise, trim the fat.
I love the analogy of the child’s “but whys”. A lot of physics feels like that sometimes once you get down to the basic structure of everything. I guess that’s what Science is, a grown up “But why” to the universe.
It really isn't. I hate that analogy.
@@BumboLooks do you have a better one?
@@ponponpatapon9670 Yes.
Don't use analogies when they are incorrect and don't use them when they aren't needed. Simple.
@@BumboLooks what's your better analogy then?
@@BumboLooksI hate people who, like you, make waspish comments but who themselves can and do offer absolutely NOTHING.
Can't get over how consistently mind-blowingly excellent this show is.
it's so frickkin awesome.
I just patented a grey-matter retrieval system if you need to help with that issue. 😂
This is such a great series. I love this particular episode. We need more in-depth episodes like this one. Thanks, Matt!
More is definitely coming on this topic! We just need some more time to write them (and get them right)!
@@pbsspacetime well I’ll be there when it uploads.
@@pbsspacetime Consider the following:
a. Numbers: Modern science does not even know how numbers and certain mathematical constants exist for math to do what math does. (And nobody as of yet has been able to show me how numbers and certain mathematical constants can come from the Standard Model Of Particle Physics).
b. Space: Modern science does not even know what 'space' actually is nor how it could actually expand.
c. Time: Modern science does not even know what 'time' actually is nor how it could actually vary.
d. Gravity: Modern science does not even know what 'gravity' actually is nor how gravity actually does what it appears to do.
e. Speed of Light: 'Speed', distance divided by time, distance being two points in space with space between those two points. But yet, here again, modern science does not even know what space and time actually are that makes up 'speed' and they also claim that space can expand and time can vary, so how could they truly know even what the speed of light actually is that they utilize in many of the formulas? Speed of light should also vary depending upon what space and time it was in. And if the speed of light can vary in space and time, how then do far away astronomical observations actually work that are based upon light and the speed of light that could vary in actual reality?
More goats in underwear!
@@charlesbrightman4237 as a quantum wannabe I'll throw in my 4 pence:
a: numbers are a human construct [see 1+1 proof] and constants lack derivation by definition but allow for approximations to become "more approximate"
b & c: ya space-time might be some type of [dot] product relation but it is currently difficult to measure these "properties" with "exactness" due to quantum entanglement and current limits in MATSE
d: gravitational flux is prolly a better way to conceptualize it along with some assumptions of mass relating to one, more, or even different types of forces
e: along with the rest, quantum entanglement needs to be figured out for measuring devices to be able to produce exactness but in the mean time, relativity is a "decent approximation"
Please correct my egregious assumptions, please
Sit down looking for video to watch with lunch, see PBS spacetime notification. Nice.
Same but with a fat bowl of dank
Same hahaha
Indifferent lunch?
Same but after a pump
samesies
As someone mentioned earlier, would LOVE a catch up episode of where we stand in these topics. That is, what is 100% proven, what is still purely theoretical, and what is still just an hypothesis.
*A)* Literally nothing is 100% proven. Science, unlike a Sith, does *_not_* deal in absolutes.
*B)* "Theory", in science, is not the semantic equivalent of "guess" or "speculation". In science, a Theory represents the highest level of understanding there is. Thus there is not "Germ fact", or "Atomic fact", there is only Germ theory and Atomic theory, ETC.
Hasn't really changed in decades.
@@AlbertaGeek you're just being pedantic
@@c-djinni He/She is being semantic not pedantic. But it doesn't change the fact that it's an important distinction to make.
@@c-djinni yes alberta is but also it's necessary. Many of the current "factual" theories can be easily overturned if certain hypotheses or philosophical theories are found to be true. Like for example, the day where general relativity and quantum mechanics are unified is most certainly a day where our current "factual" theories are overturned for a more accurate one.
I love how the more we know, the more we know we don’t know.
I'm starting to think physicists are just writing quantum mechanics fan fiction at this point
Nah, you're thinking of psuedoscientists. They can send you ionized resonance waves through your cellphone signal.
Looking back into history there never was a moment when any part of it was physical. The real science is to tell who are the real authors and who are the fans in this fiction.
Well, I think there's a kernel of truth in that statement. If you noticed, the discussion took us through 3 or more models for particle and force symmetry. These are just models and should never necessarily be interpreted as "the universe must obey these laws" .
But science, or Quantum Physics in our case, seeks to describe how the universe seems to behave __ based on the observations we have made __ and good science should plainly lay out what is hypothesized. Good science also implores one to look closer and to try to tease out more.
The "good scientist" when provided with contradictory evidence derived from a "good experiment" should become excited ( and probably a little too excited from the layman's perspective 😆)
We are always looking for ways to actually prove these models (a purely artificial construct, essentially fiction) wrong. The longer they hold up, the more likely they reflect reality. 😃
I love how these titles are so shocking at first glance. Not because they're bait-ish, but because the topics are actually so fundamental to our understanding of our immediate reality that any new hypothesis in the field represents such great change.
"Charge isn't fundamental."
"What?!"
"Of course it's not. Electromagnetism isn't fundamental."
"WHAT?!"
"It's just a remnant of the electroweak force, which is fundamental."
"Oh. I guess I knew that."
@@SergeiAndropov for some reason I forgot that baryons were made up of quarks so I had the same reaction when he revealed that so I had the same reaction lol
Ive been hoping Space Time would do an entire series on SU(3) and the other special unitary groups relating to quantum physics, but I appreciate the magnitude of such an undertaking. All I can say is treat your motion designer extra nice when theyre working on that!
My understanding is SU(3) is the group of 3D rotations, AKA the surface of a 4D hypersphere, which form the basis of possible spins (including direction). I'm sure there's much more to it than that, but that's the general gist. I to would love to see an episode on that.
@@aaronsmith6632 So would I.
+1
Check out Sean Carroll's Most Important Ideas in the Universe series on RUclips. He actually makes it pretty intuitive.
@@davidhand9721 I tend to mistrust, "intuitive," particularly when applied to current physics which is anything but, (unless you're a Fields medal winner.)
As Terry Pratchet, (speaking as Ponder Stibbons,) puts it, "'That is a very graphic analogy which aids understanding wonderfully while being, strictly speaking, wrong in every possible way ...'
I''ve said it before, I'll continue to say it. This series is truly amazing and should be preserved as important to humanity. Will continue to watch for the rest of my life.
Episode co-writer here
Thank you, comments like yours keep us going
Feedback: Found this episode harder to understand as usual. Hyper/isocharge got me lost and spin as well as the fundamental symmetries are always a mystery to me.
It would help to get more background / deep dives into those concepts.
Still loved to watch it ♥
Yeah same here, I appreciated that there was at least a summary of the gist of the episode towards the end
Weird, I usually don't understand anything but I feel like I kinda got this one. Just don't ask me to explain it to you!
"Found this episode harder to understand as usual" yes but its the speaker does seem to have a speech disorder
So I’m not the only one. Thank goodness.
From charge to spin to chirality, it's funny how many things in Physics are just bi-valued conserved quantities oscillating between those two values.
I know, right?. This point towards something deep about the universe but I have no idea what
Almost like a bit flip :)
@@parabolicpanorama oh no
If you have a binary number and then you add half again the top bit value, you get 1s and 0s flipped. 1.0101 -> 1.1010. Perhaps "pixels of reality" create the dualities we see.
@@parabolicpanorama something something two's complement
I am studying this concept of isospin and hypercharge this semester and I was able to relate this quite nicely to this video. Thank you for making such amazing videos, these help and motivate a lot
I am neither a math person, nor a science person; I mainly watch these with my son, who loves this stuff. What I love are the moments when I can *see* or *feel* how it makes sense. I do not comprehend this on a scientific/mathematical level, but with Matt's brilliant explanations, the concepts drift in and out of comprehension in some vague, indefinable, "music of the spheres" sense.
I love it.
W dad
wow, this was an extra good episode. i feel like this time we truly need 4 more episodes to explain some of the concepts, but im also good with just diving deep for now. great work!
9:52 Since chirality is defined in reference to the momentum vector of the particle, does the chirality depend on the observers reference frame? If so, couldn't two different observers see the particle as both right and left handed, and then both feeling and not feeling the weak force? How do the two observers deconflict their observations?
Because chirality isn't a matter of symmetry but of topology, TheGundeck
@@micaelapizza510 Right so frame of reference needed
@@addajjalsonofallah6217 yo I found dajjal here
I think the relevant reference frame contains both of the interacting particles equally and that the chirality is well defined in that frame.
Chirality is Lorentz invariant, so doesn't change under the transformation of frames of reference.
2:25 Does anyone else think that the "spin" label should've done a 720º rotation on screen, also spinning around itself such that the second 360º rotation had the word horizontally flipped?
Yes, would be accurate.
For us, visualizing 4d space as motion is easy. understanding that spin is not really a physical rotation but force rotation. Understanding quaternion makes understanding spin easier.
@@toshirokardevaand2772 What is E=MC2 is dimensionally consistent. Maxwell's equations are fundamentally consistent WITH what is E=MC2, particle/wave duality, TIME, AND the second dimension in/of SPACE (ON BALANCE), AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE); AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE !!! Great. c squared CLEARLY represents a dimension of SPACE ON BALANCE. Accordingly, ON BALANCE, the rotation of WHAT IS THE MOON matches the revolution. Notice what is the orange AND setting Sun. Lava is orange, AND it is even blood red. Notice what is THE EYE ON BALANCE. (Consider what is water !!!) Indeed, notice what is the TRANSLUCENT AND BLUE sky ON BALANCE !!! Water comes from THE EYE ON BALANCE. Indeed, consider what is E=MC2; AS c squared CLEARLY represents a dimension of SPACE ON BALANCE. So, ON BALANCE, consider what is the BALANCED MIDDLE DISTANCE in/of SPACE !!! THE EARTH IS ALSO BLUE. Indeed, consider what is the fully illuminated (AND setting/WHITE) MOON ON BALANCE. AGAIN, CONSIDER WHAT IS E=MC2 ON BALANCE !!! Magnificent. Importantly, gravity is an INTERACTION that cannot be shielded (or blocked) ON BALANCE. Consider TIME AND time dilation ON BALANCE, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. The stars AND PLANETS are POINTS in the night sky ON BALANCE. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Great. Consider, ON BALANCE, what is BALANCED BODILY/VISUAL EXPERIENCE. The INTEGRATED EXTENSIVENESS of THOUGHT AND description is improved in the truly superior mind. BALANCE AND completeness go hand in hand. The rotation of WHAT IS THE MOON matches the revolution, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Great ❤️❤️❤️❤️.
By Frank Martin DiMeglio
Thanks for the continuing fascination! Been away from the channel for too long. Glad to see Spacetime is well
I'm no physicist, but several years ago I found myself dazzled with things connected to cosmology, astrophysics and quantum theory. When I tried to understand those charges, hypercharges and isospins my head almost blew. Thank you for this episode, I need to watch it several times to get a grasp of those concepts but I hope I'll get there. Is there a hint that you'll finally explain the Z boson?
Episode co-writer here
I wanted to cover Z bosons and their amazing connection to photons, but we had to cut it out for time. Perhaps we should make an episode just about the Weinberg Angle
@@HighlyEntropicMind please do! and/or the Cabbibo angle/CKM matrix. both equally fascinating!
@@evilotis01 This episode originally had a short mention of the CKM matrix but we had to cut it because it wasn't too relevant
Perhaps it should be its own episode
I feel very eager to hear more about the weak force.
@@HighlyEntropicMind I feel like just here we have ideas for several episodes. I can't wait for the episode covering Z boson and Weinberg angle.
I am on board every time Dr. Matt offers to "annoy the universe."
Can relate to "but why" lol😴
"disrespect your surroundings" NO
"annoy the universe" YES
@@thenasadude6878 yes 🙂
This was a truly spectacular episode and has me hooked for the follow-up!
This is so exciting. Matt and the PBS team explain this stuff so clearly, and they cover bits that are skipped over or lost in so many books on these subjects. When I finally have money to call my own I'm joining in with a subscription
I adore how subatomic particles seem to inch time forward and direct it, all by pure fundamental properties, and the fact that there's distinction between a particle's "left and right".
I can't quite grasp what it means for two forces to "become one" at high energy. What would we see differently if the forces were merged now, at our normal/current energy levels?
Well, for one, neither protons, neutrons or electrons would exist. So it would be a bit hard to observe for humans :D
The thing is, most of the structure of the universe around you comes from these symmetry breakings. For example, at high enough energies, there is only one stable value the electric charge can have - zero. But at lower energies (such as are common in our universe today), there's two - minus one, and plus one. That gives the universe a whole lot more options to build structure (while also making it a lot messier). Of course, this is very simplified - a more accurate way to picture this is to realize at these higher energies, electromagnetism and the weak force are indistinguishable, but together still produce a broken symmetry of another kind. Until you increase energy even higher, and the two also "merge" with the strong nuclear force. Maybe.
There's a pretty nice and understandable explanation of how these mechanisms work by prof. Strassler, for the case of "how the universe would look like if the Higgs field was zero on average": profmattstrassler.com/articles-and-posts/particle-physics-basics/the-known-apparently-elementary-particles/the-known-particles-if-the-higgs-field-were-zero/ . It's not that the electroweak force is "composed of" electric and weak forces - it's that when the Higgs field is non-zero, parts of the ("more fundamental") hypercharge and isospin forces interact with the Higgs field, and parts of them don't. The ones that do form the weak force, the ones that don't form the electromagnetic force. If you add enough energy, the broken symmetry ("this interacts with Higgs, and thus behaves X, this doesn't, and thus behaves Y") disappears. Of course, that's the _standard model_ 's view of the matter, which isn't necessarily how the real world works. But it's been rather successful so far.
@@LuaanTi Makes me wonder if the symmetry ever actually broke and we're not just missing part of the picture. Especially since it is apparently (theoretically) reversible.
Perhaps unsurprisingly, they've done an episode about this very topic. Here it is: ruclips.net/video/qKVpknSKgE0/видео.html
@@Llortnerof It's not something that was "right" and then got "broken". "Broken" doesn't have any negative connotations in this context. It's just that a symmetry was there, and now it isn't there. Broken symmetries are not a bad thing - they make complexity possible. Imagine a world where electric charge can only ever be zero - that's the symmetrical scenario. Not much interesting going on in that :)
@@Llortnerof I believe that "broke" should be understood as working independently at the current energy density levels that we observe in our universe. So yes, they are reversible, perhaps locally by using a lot of energy , but at any non-local level there isn't much evidence, if any, that it would be reversible by the end of time. Perhaps conformal cyclic cosmology hints at some universal reversibility, although in that framework the concept of reversibility might need some adjustment.
Disclaimer: I'm not at all a physicist, so I may very well make silly logical mistakes. I don't even comprehend the amount of energy required to unify electromagnetism with weak force, and whether we are able to produce it in particle accelerators, now, or ever. It may even be that Matt even mentioned it in this video, but these videos are always denser than my brain intake pipe can take.
Hi Matt & PBS Spacetime, really enjoyed this episode - many thanks.
One piece of feedback: I personally much prefer when consecutive episodes deal with one particular topic at a time, than when topical episodes are spread over time and interspersed with one-offs. I find myself more engaged with a series where I know that the next episode will address some of the questions that were left open. Just something to consider!
Fascinating. Thank you for explaining a complicated subject in an easy to understand way.
Question: does "having no charge" = to "having + and - charge in a same time" or does it really mean "there is no charge" ?
The first one, usually by "no charge" physicists mean "no charge in total". For some fundamental particles like a photon, however, it can be known that it can't be composed of smaller charged parts either
@UC3TXQc7HGjVyorKL7sxw87A It is not, since if you randomly decide that, for example, some arbitrary positive charge is now zero, these "zero" charges would still repel. So no, not arbitrary
Not exactly "in a same time" being electrically neutral means having the same amount of positive and negative charge.
@UC3TXQc7HGjVyorKL7sxw87A No. "Charge" as the electronics term is behind quite a few layers of abstraction from the physics term, they are not the same thing. Zero charge in physics is not arbitrary.
@UC3TXQc7HGjVyorKL7sxw87A no, fundamental charges seem to have a definite finite set of values it can take for fundamental particles, of which zero is definitely one. Zero charge basically means that if you mathematically write down the theory you are working with, a particular term isn’t present (ie in the standard model the term ΨΑΨ is not present for neutrinos, effectively multiplied by a charge of zero). What this means less rigorously is, if you think about “particles in quantum mechanics propogate as a superposition of all the possible paths (and interactions) they could take” interpretation of quantum mechanics, then zero charge means there are certain paths/interactions that can never happen.
I feel much more photosynthesis after watching this. Thanks
14:33 I always love this! those post-pre-credits are always so well written, and delivered! Kudos!
Listening to these casually at work, really makes my day. Thankyou
one of the most fascinating videos i’ve seen in this channel! thank you for blowing my mind weekly 😊
Episode co-writer here
Thank you so much. I hope to keep blowing your mind with each episode I write
@@HighlyEntropicMind Congrats on writing a brilliant step by step explanation of electron charge that ended up as a backdoor explanation of how the Physics Community makes advances.
From the thought processes of Heisenberg and Gell-Mann behind their fundamental theoretical contributions that resulted in experimental confirmation leading to the Nobel prize that also stimulated development of quantum chromodynamics while including an exploration of the interactions of how those newly discovered particles are designated and used to break down and explain those same experimental results with a three dimensional geometric representation of properties of state while subtly adding their relationships to exclusionary principles, chirality and symmetry groups emergent within the particles carriers of the fields that transmit the basic forces of nature.
An easy to follow introductory “How Physics Works” course explaining the basic tools and processes behind our impressive progress in understanding done in less than fifteen minutes that should be a part of intermediary Physics classes.
Neat episode, as always! But I think you should either have called your definition of "chirality" helicity, or used a different definition. Telling helicity apart from chirality (or just understanding chirality) is hard enuogh. Better to get the terms right from the start!
For those interested: Helicity is the described projection of the spin on the direction of movement. Chirality is a related property of the particle/wave function, but it is only identical to the former for massless particles. Particles with mass can have an admixture of positive helicity state in the negative chirality state. So while the coupling does indeed only happen to the left handed (negative) chirality state of particles, the W bosons _can_ couple to the helicity right-handed electrons, but it is suppressed. It is less suppressed for muons, which are more massive. This is the reason why pions decay mostly into muons, instead of electrons! Also, it is the negative helicity that is allowed for particles, but anti-particles are preferred in positive helicity by the weak force.
Getting these nuiances right might take too much time in a video like this. But just dropping an "for massless particles" in the explanation would have made it correct. But then it would have raised questions about how that applies to the electron and neutrino who definitely have mass? Phew, writing educational RUclips video scripts is hard....
I did NOT know that about the muons. That explains a question I've had for some time now. Thankyou for enlightening me.
I 100% agree with your last sentence(, and with the rest, but considering I kinda almost understood it, my opinion is not relevant). I was already happy that I had a grasp of what chirality is when I heard Matt saying the word, so I didn't need to pause and google. And then I read your comment that ACTUALLY helicity ...
If he would have said helicity, I would not have known what he's talking about, and if he would have explained it (as you did, thanks!), I would have (and had, based on your explanation) concluded that it's chirality with extra steps. Yet if he would have said, as you suggested, "for massless particles", I may have been triggered by that weird mention in the context of particles with mass.
It must feel frustrating for Matt (and PBS Spacetime team) to dumb things down and then say things that they know are technically incorrect, yet the most correct that is still understandable for the target audience. I believe their target audience is rather people with my level of understanding than your level of understanding. I'm sorry for you, because I'm sure I'm getting much more enjoyment out of these videos than you can.
Co-writer of this episode here
You are right that our definition was helicity and not chirality. However the Weak Force cares about chirality and giving a proper definition of chirality and whi its different from helicity was just not possible without making the episode way too long. We settled on this solution because it gives people a good enough understanding of chirality, even if its imperfect
@@HighlyEntropicMind ah, the compromises we physicists have to make.
Since you're responding, might as well pick another bone, and that's the abuse of the English language (tbf, nearly universal among physicists) involved with the phrase "the Higgs field is what gives particles their mass."
This poor word choice particle physicists use to talk to each other about how to construct Lagrangians needs to be BANNED from lectures to lay audiences because it is so misleading. For the love of... understanding...NEVER use that phrase in popular discussion again!!! I'm begging you!!!
I usually watch this channel to learn some new words I can use in Scrabble, but today I also learned that some particles are created in pears, so keep up the good work Matt!
This is my favorite Channel on RUclips I hope you guys never stop
This is really one of the coolest episodes in a while, I learned so many new things. I can’t wait to hear more about the electroweak connection and all the deeper symmetries and what kinds of interactions emerge from them.
Episode co-writer here
I am so happy you liked it. This episode was my idea, and yes, we are planning more stuff about the electroweak interaction and more weird things in particle physics, since that's my specialty. Stay tuned
All these layers in physics seem to resemble derivatives somewhat. We have some properties we can observe, then we can find some values that determine what those previous values are, and so on, and so on.
If you think about it this way, then certain values that determine the values of things we perceive are simply zero - since a derivative of a flat line is zero.
At some point in physics, I reckon we'll reach this level and start asking questions like 'could this even more fundamental value be changed, and if yes, what would happen?'
I wish I'll live to see that day.
I used to date the third time derivative of position, but she was a jerk.
This was one of the best episodes in a while. Kudos Matt!
I'm so glad you did this video. I've been thinking this for a while and there's not many good resources on it.
What does Noerther's Theorem say about the conserved quantity of electric charge? Shouldn't it produce a related symmetry? I vaguely remember electric charge being tied to phase symmetry in the wave function.
I asked this same question to one of my physics professors when he was talking about Noerther's Theorem. He said the related symmetry was the gauge freedom of the electromagnetic four-potential. The electromagnetic force is given by the exterior derivative of the four potential, so you can add the gradient of any scalar to it without affecting the resulting force. I don't know how exactly this works with Noether's theorem, but if we put the four potential into Lorenz gauge then conservation of charge falls out of the relativistic Maxwell equations.
Co-writer of this episode here
You are right. Electromagnetism follows U(1) symmetry as per Neother's Theorem and the conserved quantity is electric charge. However if we use the full U(1)xSU(2) symmetry we find two conserved quantities, isospin and hypercharge, and hypercharge. When these two properties combine they preserve the U(1) symmetry, which I know, it's kind of a mindfuck
@@HighlyEntropicMind Co-writer, really? Neither OP nor you managed to spell Noether correctly.
That bit at the end: Chocolate-covered particles... truffles and such... what a concept. Have to eat them fast because some decay quickly, and some taste "strange" LOL You should make an assortment of them, it's a new discovery: The elecro-yummy force.
But since they decay so quickly, you could eat as many as you want without gaining weight.
Be careful of the mini black holes, they'll pucker your mouth harder than the sourest lemon drops.
I've just discovered this series of videos and they are GREAT! Hard science that doesn't dumb it down
Matt and the Space Time team, thank you so much for exposing me to the world of physics! This channel is my guide and my inspiration. Your work is deeply appreciated ❤
Important physics question: Who is the guy with funny hair that often pops up on the videos looking very surprised?
i also want to know!
I'd love to know if there is a reading list that explains in long form all the principles discussed here. I'd like to understand this deeper but I don't know where to start
Never managed to make much sense out of Isospin or Hyper-charge before, well done looking forward to all this being developed further.
Now that was interesting! I really enjoy the exploration of deep, weird parts of science like this, I hope to see more!
Been waiting for this episode all my life. Electromagnetism and electric charge really twists my melon, man
What I am dying to know is how this weak isospin/hypercharge relates to the local phase invariance of momentum. Based on previous episodes and some Stanford lectures I've watched, the EM force (U(1)) appears like magic when we subtract the offending (non-invariant) term from the integral. I've always wondered what this says about electric charge and magnetic moment due to spin. Now you've made it even more complicated by also deriving charge from weak isospin and hypercharge. So transitively, the weak parameters must have some role in the wavefunction's local phase invariance in momentum? Am I way off track here?
This was fascinating! A walk through the quark zoo is always interesting to me - thanks!
The music at the end of the vid is so subtle and perfectly placed when the conclusion is about to be revealed. This channel should be nr1 on this platform.
Would have been nice if, when you were talking about Murray Gell-Mann's idea of quarks you had mentioned that George Zweig had the same idea. What happened to him by the way?
The fact that the weak force and the Higgs field only work on left-handed particles is...well, something worth looking into, at least.
I need a primer on quarks. Any suggestions, until Matt and team have time for one?
One of the BEST videos lately. Please more about electromagnetism!
I remember a science comic posted in my university's physics building, it went something like:
"There are four fundamental forces in the universe, but we don't understand one of them."
"The…weak force-?"
"It's gravity."
I'm very curious about the weak force because it's often skipped over as "blah blah beta decay, moving on", so I'll be paying close attention to this string of episodes.
Question: If chirality is defined by a particles spin relative to it's direction of motion, but it's direction of motion is relative to the observers frame of reference, is chirality relative to the observers frame of reference? Is a particles ability to interact with the weak force different for different observers?
I suspect either I'm missing something, or I'm trying to apply imprecise definitions to cases where precise definitions are required.
There's already another thread where this is discussed, it appears the answer is (not that I understand any of it):
"... helicity determines the superposition of left and right handed chiral fields, so that how much of that particle is left-chiral does indeed change under Lorentz transformation. It therefore also changes the probability that that particle interacts with a weak isospin gauge boson. The thing is that the W and Z bosons are not pure gauge bosons, they mix with the Goldstone bosons and that resolves the apparent paradox." (Guest6265+)
-Also that most particles with spin are massless e.g. lightspeed particles and thus essentially don't exist to any observers not in front of it.
When you say, "the breaking of electro weak symmetry", that makes me wonder about that symmetry. What are the particles and interactions in a universe before the split?
Great question, the particles were only "potential" and they appear when the aperture in space down to the corresponding temperature in the BB space grows and persists.
@al h
As I understand it the Higgs field changed during the split and prior to the split all fields were massless. The universe was purely energy.
According to the standard model, there were three bosons for the weak isospin force, and one boson for the weak hypercharge force. None of them massive. One of the isospin bosons and the hypercharge boson "combine" to form the massless photon and the massive Z(0), while the other two isospin bosons form the massive W(+) and W(-) (which also explains why the mass of the Z(0) is different from the masses of W(+) and W(-)).
For what we'd call the matter particles, they are themselves a combination of pairs of fields. For example, without the contribution of the non-zero Higgs field (and at high enough energies), you get a left-electron and its friend left-electron-neutrino (both non-massive, isospin and hypercharge interacting), and a right-electron (non-massive, hypercharge interacting, _not_ isospin interacting). It's also possible that there's a right-electron-neutrino as a pairing for the right-electron, but notice that it doesn't interact with anything, which makes it rather hard to confirm its existence :D For the quarks, a similar scenario is with left-top and its friend left-bottom (both non-massive, isospin, strong and hypercharge interacting) and right-top and its not-quite-friend right-bottom (both non-massive, strong and hypercharge interacting, _not_ isospin interacting). The only massive particles are the Higgs bosons - in fact, four different Higgs bosons.
@@LuaanTi thanks for the replies. Videos exploring the nature of universes at earlier metastates would be awesomesauce!
Co-writers of this episode here
Before the split there was no difference between the two quarks of each generation, or between the two leptons of each generation. The universe was made of only three quarks and three leptons freely exchanging isospin. When the universe cooled down particles became locked in whatever isospin state they were and they gained different properties of charge and mass accordingly
WoW really enjoyed the episode it was very enlightening, can't wait for the follow-up you mentioned near the end. Thanks!!!
This was a subject I've been looking forward to them covering for a long time
It sounds like there is a force in the middle of the particle that is holding it all together with a force like gravity, but at only a tiny scale. Is there a name for that point? Could it be dark energy?
the strong nuclear force
Imagine if we could find a simple way to flip the charges of the proton and electron, turning them into antiprotons and positrons. If we could flip hydrogen into anti-hydrogen, antimatter energy would suddenly become MUCH simpler and easier to generate than fusion will ever be.
If?
Anti-matter has already been created in the lab.
Antimatter is the most expensive substance on earth at $62.5 Trillion dollars per gram
@@PetraKann You didn't actually read my comment.
Positronics could be worth the hype Isaac Asimov gave it.
Cool idea, but antimatter is not just opposite charge. There are also other properties like chirality that need to be flipped. I doubt flipping only the charge would do the trick.
@@feynstein1004 Alright, but even if this new matter couldn't be called 'antimatter,' maybe it would still do the trick/be useful.
I really really liked this episode and I’d like to see more like it. Can you do a similar treatment for the “goldstone bosons”, which I’ve seen but not fully understood to be more fundamental versions of other bosons? In fact I’d really like more QFT deep dives in general. It’s really hard to find channels that aren’t afraid of your level of detail and I love it
The beginning of the video is exciting getting straight to the intriguing questions that challenge the "fundamental" status and ask what, why, how? I've been looking for more physics content like this.
✨️🍵🙏
Is there some hypothesized "anti-weak" force that affects the opposite chirality of fundamental particles?
Yes, they are creatively called Left-Right Symmetric Models.
How can it be certain that particles carrying weak isospin and weak hypercharge are fundamental and not another instance of an emergent phenomenon like with isospin and hypercharge with SU(3)?
afaik the answer is that strong force isospin/hypercharge are actually abstractions of the properties of the smaller components (i.e. quarks) inside the proton and neutron, whereas weak isospin/hypercharge apply to particles with no internal structure, and thus can't be abstractions of any such structure
That's what I thought too 🤔
@@evilotis01 well, no internal structure for now .-.
Episode co-writer here
Imagine you and your friend threw basketballs at each other so strong they explode when they crash in midair. Then you and your friend record where the little pieces of the ball ended up after the explosion. Now imagine you and your friend did the same with with bags full of marbles and recorded where the marbles eded up. As you can imagine the results of basketballs crashing is very different to bags of marble crashing, and you can use statistics to quantify why and how they are different
That's what we did in particle colliders. Protons and neutrons explode like bags of marbles, but electrons and quarks crash like basketballs. From this we infer that electrons and quarks are not made of anything else
Sure, new evidence could be found in the future that made us conclude they are not fundamental after all, but so far all the evidence we have points to these particles being fundamental
This channel never lets me down.
Although it revolves around complicated things, theese are well explained to me.
Each time i have a glimpse of a deeper understaning of some aspect of nature, i am more and more curious about it.
Keep up the good work.
Wow thank you so much for amazing content like this. This was one of the most fascinating videos I’ve ever seen of you! I love this channel for going really deep into that matter.
I love your videos so much, I'm a medicine student in Brazil, it would be really hard to access such deep level of knowledge about our universe and reality without channels like yours. Thank you!
Brilliantly explained, Matt. The 'very early universe' seems to have been a very interesting place which existed for almost but not quite no time at all (apologies to Douglas Adams). I can completely understand why there are people who devote their entire lives to working it out - it's absolutely fascinating. I think you should sometimes mention what you mean by 'the very early universe'.
Excellent descriptions, and elucidation on the topic!!
Excellent! Thanks for the continuing work 🙏🏻
here's a question i've never seen answered: the difference between the proton and neutron's masses corresponds roughly to the mass of the electron, and when the neutron decays, it decays into a proton and an electron (and an antineutrino). so: is there some sense in which a neutron is essentially a "combination" of a proton and an electron?
A neutron only appears to be the same weight as a proton+electron, this is because of Cavendish tensors in the atom, the first neutron is in fact twice the weight of the proton (i.e. 20c^3)
A proton is 2 of one type, 1 of the second, neutrons are opposite.
1 has a charge of + 2/3, the second gas - 1/3.
Yes, that is how neutron stars become all neutrons. Gravity causes the electron to be absorbed by the proton.
@@Mernom You are thinking they have to combine in some way , when you should just think about the relative temperature, i.e. Proton = +10ºC and Neutron = +20ºC, to combine them you need to use half phased interference.
Charge is relative to weight, weight is relative to temperature.
Temperature red shifts as it finds stability in the weight space.
@@filonin2 An electron is not heavy enough to be absorbed by a proton, 2 electrons combine to become a new proton is the only way this could happen.
So if electroweak force split into electromagnetism and weak force as temperatures dropped, is it possible that our familiar forces can split more if we lower the temperature enough? Or instead of possible (because physicists have this annoying tendency to simply say "yes" and move on) - how likely is it that this will happen?
Great question.
When forces split, particles are created. So likely new types of particles and possibly ours would fall apart so to speak.
Edit maybe some cool monopole and massless or weakly interacting hadrons or something cool 🍻
Re edit
Maybe that is how gravitons will be genesized, to coalesce and attract all matter in the universe back into a fuzzball to start all over again.
No, unless there's a new particle we don't know about. Every force needs a force carrier to propagate it.
The electroweak force had W+,W-,W0 and B0; but with the separation of the weak force and electromagnetism the W0 and B0 turned into the Z0 and the photon. 2 particles in, 2 particles out.
If the force were to split further, there would need to be a new fundamental particle (dark matter?) to mediate it.
that's a really interesting question. i'm no expert, but i'd suspect the answer is "no", simply bc while temperature can increase indefinitely, there's only so it can fall. we've reduced the temperatures of various substances to basically absolute zero already, and while that certainly gives rise to interesting states of matter-superfluids, Bose-Einstein condensates-afaik it doesn't seem to affect the forces that govern them.
This question is a actually quite complicated and it is easy to accidentally misinterpret the physics. One subtitle point is thinking in terms of temperature can cause issues. Temperature is a collective property of a large system of particles measuring the amount of ‘random’ energy and is linked to the entropy of the system. For electroweak physics, really what you need to think about is the local energy in the Higgs field. After the Big Bang the Higgs field was at an extremely high temperature (which crudely implies high energy) and so forces unified. However, at the LHC arguably the temperature is almost zero, because it isn’t a large system with large random energy. Rather, at the LHC you deal with single high energy particles. Regardless, forces unify in just the same way as in the Big Bang.
So it is complicated to say what a new lower temperature splitting of the forces refers to (at least without specifying a system). As for electro-magnetism splitting further at low energies, within experimental bounds that’s very unlikely without a drastically new understanding of fundamental physics since we can isolate almost static single electrons up to limits due to the uncertainty principle. However, it could be that there are undiscovered super low energy particles out there in the universe - with extremely low temperatures (a candidate might be sterile neutrinos).
Also, there are a lot of constraints on which low energy particles can exist in the universe from looking at the CMB and measuring cosmological freeze out (I mention sterile neutrinos as they are an example that can get around these constraints).
Very perfect timing, cuz I've been looking at QCD for a week now, and I made a rather screwed up simulation of color charge where I tried to render the field lines, and it looked rather funky.
I do wonder if there would ever be a video that might explain how color charge works in a very deep manner.
Very happy that you are exploring in depth the most fundamental aspects of our universe we know of.
1:17
One young night driving looking up asking,
why does the moon follow us?
No proper answer given to suit my imagination,
nothing quite as empty as because.
imaginary technique: purple
I was looking for a comment like this. 🤌🏻 🫴🏻 🟣
This is my favorite channel on RUclips! Keep it up!
Ive been waiting for this episode for years
Gojou Satoru
I find it interesting that the universe appears to be neutrally charged (perfectly balanced with no net charge) but that there is a matter / anti-matter imbalance. That is to say, equal numbers of electrons and protons, but unequal numbers of electrons and positrons.
i am actually not sure whether we can prove or assume that the universe is absolutly neutral, because charge evens out? Maybe there are more electrons than protons, would we notice?
@@macrozone yeah, a small net excess of electrons would be hard to detect since they would repel each other... hmmmm... which would act like a dark energy.
a net charge would tend to expand the universe. maybe
Really the best explanation of the universe and how it ties together 👏
10:46 - "Weak isospin is effectively the charge of the weak force, carried by these W bosons." Glashow's 1980 fermion-cube mnemonic helps. Eight "isovectors," all parallel to Maxwell's electric displacement axis, link the corners of the two Glashow cubes to form a hypercube. Point the 8 isovectors up, and you get the positron, ups, anti-downs, and neutrino. Point them down, and you get the anti-neutrino, downs, anti-ups, and electron. Colliding an up and down bridge (e.g., u, e) sometimes flips both (d, nu). That's a W[+,-] exchange. The bridge figure is quite beautiful and an easier way to remember W options.
Addendum: Anyone interested can now see a full-color image of the isovectors hypercube, as well as an example of an isovector weak spin exchange, at:
sarxiv.org/apa.2022-08-05.0945.pdf
Given that the forces operate at different ranges, could the expansion of the universe be what's pulling apart 'layers' of forces from one another?
Well as far as I understand it's the amount of energy in an area. In high energy and density environment they were one force. Expansion caused lowering of local energy so you are partially right.
Don't know what you mean by 'layers of force,' but it's expected that there is some unification occurring at high energies/very small scales, in conditions that resemble the very early universe. You can look up 'Grand Unified Theories" or GUTs, for more info.
I've read Einstein wondered if someone smart enough could work out the laws of physics just from the fact there's something and not nothing. This is probably the most fundamental property there is.
I've personally wondered about Spacetime. It gives everything the property of relative position and relative time, but just what is it?
Spacetime is just all the something that makes the universe not nothing, isn't it?
There's a lot of possible somethings out there. You couldn't get to our physics purely via thought experiments. There's too many other consistent approaches.
I work in microbiology and the well funded labs I've interviewed for all had PIs that availed themselves to religion and mysticism to develop their ideas of what's beyond what we know. Modern theories of the multiverse and cyclic universe are influenced by judiasm and Hinduism. It may seem lazy to say space time is the "body" of god but as someone's who has been medically dead, experienced the "godhead", and woke from a coma with this idea in my head, I'm pretty sure about it. "God" pours itself into the multiverse to experience limitation and separateness. Like a wave, you come in and out of the unified godhead into the incarnate multiverse. Hinduism, Buddhism, judiasm, and esoteric/heretical Christianity all claim similar things about the universe.
I think pondering these things helps us as thinkers imagine and venture into the right direction using our much slower but reliable processes (science).
Think of God as infinity. Remember how the quantity of numerals between 1 and 0 is infinite too? I think that's the makers mark.
The gnostics refer to the material universe as the demiurge, the evil God, God's ego. The infinite and unbounded basic consciousness that pours itself into the universe, that's the abstract God that people worship as the God above all gods.
I mention this because as I'm making the shift towards biophysics the fundamental physical laws seeme
to be arbitrary as well as beautifully orchestrated.
@@DanielSanchez-yi9cr That's right.
Man, nothing blows my mind like these videos.
I only wish I had even a single person to discuss these kinda things with IRL.
You’d think that being in orthodontic residency, our 10th year of college, that some of the people around me would like learning about science as much as I do…but nope lol
Quite a few microcuts, for the sharp eyed. This is a seriously densely written episode. Pause, rewind, rewatch. Great stuff. Old UK duffer here :)
It's interesting that you should release this video right now, as I've been wondering this same thing myself recently. On another note, I have no children myself, but if I did and they asked 'but why', I'd be ecstatic, as it points to a mind that is trying to find systemic reasons to things, rather than just memorizing random, individual facts, well, individually. This, in my mind, is a strong indicator of intelligence.
Not Gonna Lie
This Exact Question I Asked My Teacher And He Completely Refused Me And Said Not To Focus On This Thing 😑
But I'm Happy To Find This Video 😊😄🥳
Wow! - this joins so many dots and is so dense that I had to rewind a few times. Things like spin change on an electron requiring a photon to transfer - never knew that. Just wow!
Inspiring to see the logic exposed in this way - great job. Probably - no, definitely - the best thing I’ve seen this Christmas.
Thanks guys. 🎄
No matter how many times I ask youtube to not recommend this channel to me, it still ends up in my feed.
If the weak force can transform an electron into a neutrino (and presemably the reverse), doesn't that imply that those particles are not fundamental and have internal structures of their own, the way protons and neutrons do?
Episode co-writer here
There are three kinds of leptons: electrons, muons and tau. Each has its own kind of neutrino: electron neutrino, muon neutrino, tau neutrino. They can transform into one another by changing from Isospin Up to Isospin Down and viceversa. What this means is that in some sense they are not six particles but just three. In some level an electron and an electron neutrino are the same particle in different isospin states.
Think about regular spin, you couldn't call an electron with spin up a different particle form one with spin down, right?, why should Isospin be any different?
However we do have to consider that changing Isospin is much harder than changing regular spin, because the W bosons have mass and photons do not, which means it takes a lot more energy just to make a W boson in the first place
@@HighlyEntropicMind Well, the three types of neutrinos can transform into each other through the process of neutrino oscillation. Wouldn't that imply that there is in fact only one lepton particle, along with its anti-lepton version?
@@francoislacombe9071 Yeah, neutrino oscillations along with the CMK matrix make all of this more complex
What happens is that the identities of the particles are not perfectly "aligned" with the masses they are allowed to have, and that's why this mess happens
This is my tinfoil theory: originally there was just one kind of particle, through one symmetry breaking it became two particles, the first quark and the first lepton. The second symmetry breaking separated them into three things, the three generations of particles. And finally a third symmetry breaking separated each of the six resulting particles into two
I was recently given test by doctor and she tolt me that my "iq is 68" which means I can't understand anything from this video. Even though I watch ALL of it. I have magnets but I like movies. 👍
good for you pornsak
Man, I keep on coming back to this video and realizing new things. I love this video!
It would be excellent to see a deep dive into symmetry given it's a word / topic that comes up quite often in your videos.
hi Spacetime! Can y'all do an episode about colonialism and astrophysics? I see a lot of the casual interest and even special interest not astrophysicist and astronomers taking very ugly standpoints on the construction of large telescopes on Indigenous land (as an example) and believe that the unspoken or at best off hand references to the intertwined history of western astronomy and colonialism as very regressive. The channel regularly makes reference to the history of astronomy during times when european capitalist and nations where murdering millions and stealing huge swaths of land and not even a mention of the connection between the funding and colonialism. Y'all have covered what I would call very off topic and speculative things like asteroid mining. Why not past and present colonization and how astronomy and astrophysics plays a part and, most importantly, doesn't necessarily have to.
This episode brings home the fact that some concepts require a deep dive into the mathematics to be best understood.
One of the best, content and presentation, I like this speed a lot better
Gonna have to rewatch this one. I always have rewind cuz you'll say something and my mind will go off thinking about it and I'll miss a bunch of the video. Fascinating stuff