Hats off to the animator for the episode! This channel usually has great graphics to help explanations, but this time there was a lot, and it was outstanding.
Ya. The graphics really help me understand ( and even speculate on other instances). Which really helps me learn and remember the topic(s) they're explaining.
So far this was the simplest yet still basically accurate visualisation of superconductivity. Beautifully concepted! Whoever did the anymations deserves great praise! I would have also added that in the same way you can have superfluid, when the fluid particles group up into "bosonic sects" and after that they just ignore everything outside their group (just like in real life sects), and the fluid becomes frictionless. Also there is the cool concept of high speed electronics, when the electrons are robbed of 1 dimension of movement (2 dimension electron gas) and forced into lattices, which limits their quantum states, also making it more easier to form quasi-bosonic groups. The whole concept of real life particles playing MMORPG to "pretend" to be imaginary particles and as such taking on new skills and perks is just hilariously funny! Lotsa wonderful and exiting thing are behind this specific topic of nature.
I like how in the introduction the visualisation of the grid plays a nice little optical illusion: the white dots appear black when you're not looking directly at them. Quasi black dots.
I love how PBS keeps changing their mind. They have videos talking about how quasi particles don't exist.. lol PS: Only quasi particles exist. Real particles don't exist. The double slit experiment proved this.
These are some of the best videos on the internet. Other producers--feast your eyes: the content is relatable and they trust their audience with the science in all its glory.
Being a musician I really like the concept of there being a quantum of sound. The fact that it plays a significant role in condensed matter physics is just a plus!
I love this topic, especially as I was recently trying to explain to my brother how electron holes (quasi-positrons?!) flow in a semiconductor, as a macroscale quantum phenomenon.
I had the exact same thought. I always look forward to a new Space Time, and usually learn something. This episode made so many of the bits of knowledge at the edges of my understanding just click into place.
@@fbkintanar Now all you have to do is to forward this video to him so that he will understand it and be able to unravel the confusion you told him about? LOL-ish
Always love to see solid state physics on this channel! It warms my materials scientist's heart (via a quantum scale buzz of phonons). It would be cool to see more on some of the quasiparticles you mentioned and but didn't have time to cover (or even ones you didn't mention, like plasmons).
Oh my god I literally just ranted about those in the comments too😂 I've read surface plasmons could be used to exchange quantum information between photons, which could lead to radically more heat-tolerant quantum processors, where light is used to carry qubits from logic gate to logic gate, instead of supercooled electrons
This is the best description of the workings of these diode junctions I have seen. I have read a few book descriptions which always seem to confuse as much as explain. It is a pity this stuff was not around when I was doing my science degree over 50 years ago when it was so difficult to get any information on anything. What a great age it is now for anyone interested in these topics.
I took a circuits course in college that discussed things like diodes. I didn't really understand them to the degree I do now after watching this video. Both the conventional description and the quasiparticle description uniquely illuminated my understanding of diodes, emergence, and physics in general. Yeah, it was much more difficult to conceptualize everything before PBS Spacetime and all the other good educational content available now.
You know I’ve read books on semiconductors and never really made the intuitive leap you just gave me regarding n-type and p-type semiconductors until now. Thank you, what a lovely presentation.
I was an electrical engineer long before becoming a physics teacher, and I've watched your channel for a number of years. But this show episode is one that got me really quite excited. And that's not excited because you've shown me something new, you do that often enough. Excited because it's something new that's hiding itself on the reverse side of a basic schema that's in plain sight. Good work here my man, this episode was definitely reinvigorating.
does your excitement give rise to a quasi-particle, like it does with excited electrons in a crystal? could you describe it as a wave/field with quantized (energy) levels?
Hello, Matt. I notice that there is *ANOTHER* Matt, this one called Matt Parker, and he discusses many topics in mathematics. Could it be that Matt O'Dowd and Matt Parker are a virtual pair of particles which could act as a composite quasiparticle? I would be interested to know what would happen if they got together? Something tells me that the Parker wave function and the O'Dowd wave function would make a new particle with many interesting properties. Exploring this could prove to be very fruitful.
Always a fan, but I really enjoyed this one. It hit a sweet spot for me where I somewhat understand your description, but I was also amazed (and delighted) by the consequences. Also it brought Cooper Pairs from 'heard of, but no understanding' into the 'vaguely understand' category. Just glorious. Thank you.
I just play all these videos on repeat and slowly get smarter. 3 years ago, I didn't know anything about physics. Today, I'm more competent than all my friends and can have a reasonably deep convo with my uncle who's a physicist. Thank you Matt and thank you to the entire PBS team!
Incredible explanation. This made more sense of quasi-particles than an entire semester of solid state physics. Would love to hear your explanation for effective mass!
I dropped out of highschool because there were no teachers like you. I love your videos and I have to watch them twice to understand them sometimes 😂 I am quite good at math for a drop out and I love physics as a hobby. I even read "The Elegant Universe" in prison. Keep it coming, sir.
In the same way you can have superfluids, when the fluid particles group up into "bosonic sects" and after that they just ignore everything outside their group (just like in real life sects), and the fuid becomes frctionless. Also there is the cool concept of high speed electronics, when the electrons are robbed of 1 dimension of movement (2 dimension electron gas) and forced into lattices, which limits their quantum states, also making it more easier to form quasy-bosonic groups. The whole concept of real life particles playing MMORPG to "pretend" to be imaginary particles and as such taking on new skills and perks is just hilariosly funny!
Awesome work with this video! Another cool thing: when Cooper pairs are formed, they release a phonon with an energy of roughly 2 times the superconducting energy gap. These phonons can actually smash into another Cooper pair and split it back into two quasiparticles. This is currently one of the major obstacles in superconducting quantum computing. High energy phonons can also be generated from cosmic events like gamma rays. Some research teams are burying their quantum computers several klicks underground and shielding them with lead bricks to reduce Cooper pair splitting due to high energy particles. The craziest thing? It actually seems to be working; the underground qubits are coherent for far longer than those studied topside.
In silicon semiconductors, holes move about half as fast as electrons. To compensate for this, the conduction channels in PFETs are typically made wider compared to NFETs in the same position. Now, this doesn't strictly have to be the case, but it makes rise times slow compared to fall times, and this complicates computing static timing analysis. It's easier if a logic gate of a given type can be modeled as having the same speed whether its output is rising or falling. You could just model the gate's speed based on the slower of the two edges, but then that means your faster transistors are burning more energy than necessary for a given switching speed, and power dissipation and energy consumption are first-class concerns in modern large scale semiconductors, so you either want to size up the slower transistors or size down the unnecessarily fast ones.
@@jespermikkelsen7553 It's little like blowing wind. Molecules of air just move a little and just carry the force(charge in case of electrons) to next molecule ==> Everything works in "local scale" but if you earlier WIRE the thing it will create electricity on both ends simultaneously (similar to "violating" speed of lightning by pointing super powerfull laser into moon and fast turning around self, you will artificially make speed faster than speed of light but actually not speed of causality). Sorry, it's probably not the clearest explanation and it's not answering "why" question part ¯\_(ツ)_/¯
This is awesome! I wish I had this exact explanation available 30 years ago, when I was trying to learn the meaning of NP semiconductors. Thank you for another amazing video!
This episode was the best explanation of cooper pairs I've ever seen. Bringing in phonons to explain the how of cooper pairs makes this all add up a lot better. Also, clarifying they aren't really being pair-like, they all just flow together, also allows me to better understand the steady state environment of superconductivity.
Electrical engineer here, adding a little bit: when we talk about electrons in a crystal usually we refer to a quasi-particle that behaves like electron but has a different "effective" mass. This effective mass can change depending on the energy of the electron - which leads to some interesting properties. For example, in some materials - a high enough energy of the electron can lead it to have a lower effective mass (shifts it to a different valley in the E-k diagram).
1.Could you please consider making a video showing the idea of the Dirac sea and overall the analogies between behaviors of electrons/holes in crystals and particles/antiparticles in vacuum? 2. Is it possible to build anything like a Standard model for quasiparticles (even though the properties of those are dependent on the medium they are emerging in)?
I like the idea of a "standard model for quasiparticles" but it would be a bit like "classifying all possible songs." Even if there are broad genres there will always be something new that requires a new classification
@@n-da-bunka2650 they can't be - they are emergent entities. Consider phonons - "particles of sound". They need a material in which they emerge. We would see the material first. Also - their (quasiparticles in general) mass would have to exceed the mass of the material itself - as there is more dark matter than known matter.
This is probably like the best video on things I didn't know about science that exists on RUclips to date that I've seen. And I'm going to watch it twice.
I lost it at college when they said the holes were positive particles. I never realised how deep the rabbit hole goes! Luckily these concepts travel straight through my brain without interacting with my understanding neuron's so I'm not too affected by it all. I just use the billions of transistors in my phone for serious research into cats🤣
I've wondered for a while what a semiconductor is/how it works. It's annoyed me that I could only ever find either technical stuff dense with terms of art or explanations so oversimplified they'd barely work as dictionary definitions. I really didn't expect to finally understand that today but I 1000% appreciate it.
I am a professor at Cow & Apple University. Here, I teach young orang-utans that electrons are planets revolving around their suns (nuclei). And earth is a massive electron around the sun, a massive nuclei. Quantum indeterminacy is decided by small microscopic civilizations inside electrons.
12:45 Phonon-mediated superconductivity (the standard BCS theory) describes Cooper pairs in a singlet state (S = 0). This is required because the spatial part of the wave function is symmetric under exchange of electrons (S-wave) but the whole spin + coordinate wave function needs to acquire a minus sign after the particle exchange to satisfy Pauli's exclusion principle, so you need S = 0. Adding up the angular momenta of two spin-1/2 particles you can either get S = 0 or S = 1, so theoretically you CAN have triplet superconductivity. To this date I don't think they have found any conclusive evidence of triplet (S = 1, p-wave) superconductivity. There are some very specific platforms like Josephson junctions with ferromagnetic barriers that can magnetically align the spins of the Cooper pairs leading to the coexistence of singlet and triplet superconductivity aided by spin-orbit coupling, but "standard" superconductors (e.g. excluding high-temperature ones) have zero-spin Cooper pairs.
I was an undergraduate taking a materials chemistry course when I learned about holes. I accepted the course material enough to do well on exams, but I rejected what I learned about the models because it didn't line up with my ignorant worldview. I don't have a resolution for the layperson's misunderstanding of science - other than a combination of time, humility, and education (more PBS Spacetime).
We need science educators to start schooling the the intuitions of students to the modern perspective that quantum is not weird, it is classical limits and smoothness that is a weird fiction. You can't get infinitesmally smaller than the Planck limit. We need to outgrow the easy metaphors of earlier eras. Sunsets are celestial motion of the earth, not of the sun moving downwards. Timezones are simultaneously different across the world, and time dilates to a moving observer. Quantum effects are macroscopic too, like semiconductor band gaps, the quantum tunneling and fusion behind sunlight, maybe even photosynthesis.
@@fbkintanar "quantum effects are macroscopic too" Bose-Einstein condensates, everyone. When a macroscopic system starts acting like a singular wavefunction, then that's our cue to curl into the fetal position and accept that we occupy an infinitesimal sliver of spacetime.
My high school physics ap class was taught by a person who thought your mass changed on the moon but your weight stayed the same. Needless to say, I didn't learn much in that class.
@@ax14pz107 So that person mixed up the words? Strange, as everybody knows weight is what you determined with scales, and mass is what opposes your efforts to accelerate something. And we've seen astronauts hopping about on the moon. Either your teacher was incredibly dumb, or they just had a case of word-swap aphasia.
Wow, this is the best episode yet and one of the best science videos I've seen. Such a simple concept that also helps to understand what regular particles "are" and yet I've never seen it explained in so approachable way. Thank you.
Fantastic video, I was thinking recently about how superconductivity works and that I have to look into it sometime and I really did not expect to learn that from a new perspective going into this video. Thank you!
i have a degree in Software Dev and work in IT. Ive been in the computer industry for 10 years. For the first time I FINALLY understand why transistors work. Holy cow thank you so much
Well, now I have some idea of what a quasiparticle is, why we “created” them, and have some understanding of phonons and cooper pairs, which I’ve heard of many times but didn’t know what they actually represented. The roton is completely new to me, but then again, superfluidity is relatively new to me, I think the first I heard of it was perhaps 15 years ago.
I love when this channel posts. It’s the one channel that helps me go to sleep. Don’t get me wrong. I love science and all these topics but someone about Matt’s voice really helps me go to sleep. I been using these videos to help me go to sleep for years.
Always loved videos on such topics! Prof. Matt here's a request for you, please look if you can upload some videos on widely discussed theories like loop quantum gravity, etc.
This episode for some reason was particularly clear and digestible. I think he’s slowed down his presentation so we can take a moment to comprehend what he’s trying to explain. Good job!
No mention of magnetic monopoles? They seem a great example, as something that's thought impossible in real particles being created experimentally as a quasiparticle. Felix Flicker gave a great Royal Institution talk on them a couple years ago.
This is one of the best channels and Dr Matt has a lot of knowledge in astrophysics and he is one of the best teachers in physics and all the support to the channel and Dr Matt 🙏🤝
Nice! I study semiconductor physics so this was the first video I actually had a decent background in. Lets me gauge the level of depth for the topics I don’t have a background in. The videos always do such a good job of simplifying super complex things. Takes years reading through textbooks and resources to understand it this clearly.
Quasiparticles are one of those things I have a hard time wrapping my head around and untangling conceptually. Thank you for this episode getting me started in that direction; I would definitely enjoy more videos on the subject in the future! Merry Christmas out there everybody! ✝️🎄
I;ve been watching Matt for years, i;ve always had a somewhat piecewise understanding of superconductivity,but found it difficult to really grasp,this is THE BEST explanation i've ever heard,if you read this Matt,i raise my glass to you,thanks mate!!!
These quasiparticle phonons are so similar to photons, it makes me wonder if photons are actually quasiparticles themselves. It's the first way of thinking of them that helps me actually understand the whole particle/wave duality concept.
heh, you really explain things clearly and now I'm sure in it. I learnt this in the school, then in the university, then read a lot working as an engineer and I regret a bit that I did not had such well presented explanation from the beginning!
Thank you for explaining the concept of the Cooper pair. I see science news articles about them all the time but they never say what they are, what produces them, and how they actually cause superconductivity. It might not be a complete explanation but it at least gives one an idea of what's actually going on. That instantly makes this one of my favourite Space Time videos, right up there with the one that tells us how the Higgs field works without that BS about people crowding around celebrities.
Love the increase in condensed matter topics on the channel! Hoping a video on the renormalization group and the Ising model is coming up soon. One question I have about cooper pairs: given the mass difference between electrons and the nucleons of the lattice and their relative velocities is the picture that electrons are attracted to each other via a build up of positive charge from nucleons accurate? Wouldn't the electrons fly past the nucleons effectively not feeling the pull from the nucleons?
They’ve already done the ising model video a long time ago. And for the cooper pairs, I think it’s actually a long range pairing, on the order of 100 nm so basically the lattice vibration is also that long and the electron doesn’t zip past it as fast
@@anthonyward8805 I don't remember a video on the Ising model. Did they discuss it in terms of the renormalization group and scale invariance? I think it's a nice connection between high energy theory and condensed matter. I'm having trouble finding the video. Also, I'm still not convinced by that argument. For instance, the most probable pairing of electrons in a Cooper pair if of electrons with opposite wavevectors, for which this physical picture doesn't account for.
It’s funny, at the intro I was like “isn’t that just like electron holes?”, and then you proceeded to spend the first five minutes summarising my first few weeks in electrical engineering class! I laughed a lot at “mass: yes” for the holes too But I suppose plenty of people who like physics haven’t also dabbled with electronics :)
I was thinking the same thing. At least when I was in school for electrical engineering, we treated the electron holes at basically the same level as electrons, especially when learning about semiconductors
@@caydjj and of course that goes back to Dirac’s “electron sea”, although in that case the holes were antimatter. But at the time he thought he was using an emergent property of his mathematical model, and only realised it was a real particle later! So it’s not electron holes in the modern sense, but he called it that!
I think what we consider fundamental “particles” or field are actually quasi particles of some underlying field or something. We use imaginary numbers and such as possibly more than just accounting tricks, and if this is true, then it would make more sense to me that we are not at base level here in our 3 dimensions. I don’t even understand the concept of time as a dimension, but I keep an open mind
+1 on more on superconductors and why very clever people have spent 30 years trying to figure out Type IIs. Best explanation of semiconductors/superconductors that I have ever seen. thx much
This is mind-boggling for a layman like me, I never realized these could be treated as particles, and it makes sense considering real particles are oscillations too.
I always enjoy your videos. Since I'm a bit of an Astronomy geek/nerd myself I always enjoy learning new things about our Cosmos everyday! Thank you PBS!
Mind blown. This topic deserves and perhaps demands many follow-up episodes to explain and explore it. I am equal parts intrigued and befuddled. Waiting for comprehension...
I spotted a mistake in the information about electrons and holes: When comparing electrons and holes properties the first time, it is said that mass of the electron is constant and hole's is variable - actually, in crystals both e and h masses are variable! even more, they are direction dependent, if crystalline structure is not cubic. It is due to the fact, that in periodic potentials electrons' mass is derived from relation between energy and momentum (wave vector). The same rule applies to holes - and e and h masses can be different from each other!
I didn't truly understand how a diode works until I saw the explanation here. There's a time and place for everything and the time for me to understand the diode has come :)
That is fantastic property of our particles reality to create virtual particles and then virtual reality made of them. And again virtual-level-2 made of virtuals-level-1. (Virtual reality not in computer simulation terms). Ok, the question is: "is it possible, that our REALITY is indeed virtual of some more basic, more real particles?" Can we examine this somehow?
What about polaritons? Really curious about those, since they are used to describe the slowing of light in a medium using QFT. PS. This holes and Dirac holes I believe as well as phonons are used often in 2D materials, like graphene based materials.
Very good intro to bridging from the practical physical ideas about phenomena in states of parallel coexistence, ie wave-particle packet-envelopment of particular coherence-cohesion sync-duration resonance in quantization objectives inside-outside holographic projection-drawing positioning and condensation presences.., which requires a "double think approach another aspect of language all together. Number Theory and Logarithmic Timing-Spacing in Absolute zero-infinity pure-math reference-framing condensation-coordination wave-packaging. Good stuff.
When I was at the University studying for my BSEE (Electrical Engineering), we always used "hole" current so we didn't have to tag the minus sign along in every equation. Also the diode symbol and the transistor emitter symbol points in that direction which made it easy to figure out a circuit.
That was a beautiful experience when studying physics: When phonons were first taught, they seemed way more invented, just a specific useful way the describe soundwaves and heat in solid matter. But the more you worked with it, the more you saw that they are so similar to photons, which are also just a useful way the describe the world. The question what is "really exists" in physics can be pragmatically answered: If is makes correct only predictions, it is a real as all the other parts of physics, that make correct predictions.
I wish you'd been around when I was doing my degree. I never understood phonons. OTOH, this took me back to desperately memorising the statistical justification for treating electron holes as real objects for my finals. Oh, how I love that.
Gotten out of the habit watching Space Time video multiple times to get it, after all that cosmology recently. No complaint. This video was an eye opener, never once considered Phonons as anything other than placeholder purely theoretical "particles".
Oh my, this may have been the most informative and amazing PBS Space Time episode ever. I've always struggled with understanding what quasi-particles are, but somehow this video made is so obvious that I can't even remember what I didn't understand.
Apparently you have good self-awareness, implies you may have better understanding than may be apparent. See" "Dunning-Kruger Effect", I suspect you're familiar.
I once did an undergraduate experiment on superconductivity. Cooper pairs stayed very elusive during that. This explanation is gold. Only several years later I came into contact with phonons as part of Solid State Physics (Statistical and thermodynamic physics).
Hats off to the animator for the episode! This channel usually has great graphics to help explanations, but this time there was a lot, and it was outstanding.
Ya. The graphics really help me understand ( and even speculate on other instances). Which really helps me learn and remember the topic(s) they're explaining.
Must be the money they saved by going with a 2D grid at 1:33.
Shoutout to Ajay Manuel
So far this was the simplest yet still basically accurate visualisation of superconductivity. Beautifully concepted! Whoever did the anymations deserves great praise!
I would have also added that in the same way you can have superfluid, when the fluid particles group up into "bosonic sects" and after that they just ignore everything outside their group (just like in real life sects), and the fluid becomes frictionless. Also there is the cool concept of high speed electronics, when the electrons are robbed of 1 dimension of movement (2 dimension electron gas) and forced into lattices, which limits their quantum states, also making it more easier to form quasi-bosonic groups. The whole concept of real life particles playing MMORPG to "pretend" to be imaginary particles and as such taking on new skills and perks is just hilariously funny!
Lotsa wonderful and exiting thing are behind this specific topic of nature.
I like how in the introduction the visualisation of the grid plays a nice little optical illusion: the white dots appear black when you're not looking directly at them. Quasi black dots.
I do research in superconductivity and I love when someone explains my research better than I can do. Really really good video!!!
DO more! No one needs resistance. Unless you are reinacting the french revolution...
@@MrEiht Resistance is futile... LOL oh you KNOW someone was going to say it!
@@n-da-bunka2650 you mean fertile? Don't use these french words, kids are watching :)
@@n-da-bunka2650 I thought it was the ration of electric charge potential to electric charge flow.
I love how PBS keeps changing their mind. They have videos talking about how quasi particles don't exist.. lol
PS: Only quasi particles exist. Real particles don't exist. The double slit experiment proved this.
These are some of the best videos on the internet. Other producers--feast your eyes: the content is relatable and they trust their audience with the science in all its glory.
Matt O'Dowd is a legendary presenter as well.
Yes, superb yet simple animations & nice ambient music
@@barretprivateer8768 His Celtic face makes you thrust him. He looks and he surely is a very nice man.
I thought he was Aussie.
@@SaltyBob355 people with Celtic ancestry dont stop passing on their genes when they leave the British isles.
3:30 small correction, Boron is B, not Bo, although there is fringe historic precedent in Newland's periodic table
YES! The chemist in me was twitching.
One of the silicones was missing an electron earlier too. Top row in the left
@@koomber777 *silicons
@@vibaj16 oops! Muscle memory. I spent ages working with silicone in a lab and just disengaged my brain once I started typing
@@vibaj16 *silicon atoms
Being a musician I really like the concept of there being a quantum of sound. The fact that it plays a significant role in condensed matter physics is just a plus!
No idea what genre you play, but I could see caution labels on the speakers or instruments that read "⚠CAUTION: High Energy Phonon Emitter⚠"
I mean music is based on quantised sound too, no? we have music notes, not a music spectrum
@@Fred-tz7hs Kinda, ish. There's nothing stopping a musician from using any frequency, although they are limited to plank times I guess
Solidstate physics... Hmm, I think I like "condensed matter" name more.
There are many hints in our ancient history pointing towards lost technology based on sound to achieve various things, as well which is mind blowing.
One of the most mindblowing episodes that I have seen on this channel. Which is saying a lot considering how often y'all blow my mind.
I love this topic, especially as I was recently trying to explain to my brother how electron holes (quasi-positrons?!) flow in a semiconductor, as a macroscale quantum phenomenon.
I had the exact same thought. I always look forward to a new Space Time, and usually learn something. This episode made so many of the bits of knowledge at the edges of my understanding just click into place.
@@fbkintanar Now all you have to do is to forward this video to him so that he will understand it and be able to unravel the confusion you told him about? LOL-ish
Ditto!
Always love to see solid state physics on this channel! It warms my materials scientist's heart (via a quantum scale buzz of phonons).
It would be cool to see more on some of the quasiparticles you mentioned and but didn't have time to cover (or even ones you didn't mention, like plasmons).
Oh my god I literally just ranted about those in the comments too😂
I've read surface plasmons could be used to exchange quantum information between photons, which could lead to radically more heat-tolerant quantum processors, where light is used to carry qubits from logic gate to logic gate, instead of supercooled electrons
@@DoggARithmamazing!
bump
I'm sure they'll get round to that
Or quasicrystals - not quite the same vein as quasiparticles(probably..) but extremely compelling in their implications
This is the best description of the workings of these diode junctions I have seen. I have read a few book descriptions which always seem to confuse as much as explain. It is a pity this stuff was not around when I was doing my science degree over 50 years ago when it was so difficult to get any information on anything. What a great age it is now for anyone interested in these topics.
I took a circuits course in college that discussed things like diodes.
I didn't really understand them to the degree I do now after watching this video. Both the conventional description and the quasiparticle description uniquely illuminated my understanding of diodes, emergence, and physics in general.
Yeah, it was much more difficult to conceptualize everything before PBS Spacetime and all the other good educational content available now.
Currently studying a lot of these topics as a PhD candidate and I can confirm sir!
Thank you for the clearest explanation of how a diode works. I knew the result of what they do, but never understood how they actually do it :)
You know I’ve read books on semiconductors and never really made the intuitive leap you just gave me regarding n-type and p-type semiconductors until now. Thank you, what a lovely presentation.
I was an electrical engineer long before becoming a physics teacher, and I've watched your channel for a number of years. But this show episode is one that got me really quite excited. And that's not excited because you've shown me something new, you do that often enough. Excited because it's something new that's hiding itself on the reverse side of a basic schema that's in plain sight.
Good work here my man, this episode was definitely reinvigorating.
would you say those somethings are quasi-new?
@@jamieg2427 no not the parts thereof but the way to view it yes
does your excitement give rise to a quasi-particle, like it does with excited electrons in a crystal? could you describe it as a wave/field with quantized (energy) levels?
Well put
Hello, Matt. I notice that there is *ANOTHER* Matt, this one called Matt Parker, and he discusses many topics in mathematics. Could it be that Matt O'Dowd and Matt Parker are a virtual pair of particles which could act as a composite quasiparticle? I would be interested to know what would happen if they got together? Something tells me that the Parker wave function and the O'Dowd wave function would make a new particle with many interesting properties. Exploring this could prove to be very fruitful.
Always a fan, but I really enjoyed this one. It hit a sweet spot for me where I somewhat understand your description, but I was also amazed (and delighted) by the consequences. Also it brought Cooper Pairs from 'heard of, but no understanding' into the 'vaguely understand' category. Just glorious. Thank you.
same. that's where the smug "i know this" got punched by "what the heck"
I just play all these videos on repeat and slowly get smarter. 3 years ago, I didn't know anything about physics. Today, I'm more competent than all my friends and can have a reasonably deep convo with my uncle who's a physicist. Thank you Matt and thank you to the entire PBS team!
Great explanation of the quasi particles. Symbol for boron is B.
Incredible explanation. This made more sense of quasi-particles than an entire semester of solid state physics. Would love to hear your explanation for effective mass!
I dropped out of highschool because there were no teachers like you. I love your videos and I have to watch them twice to understand them sometimes 😂 I am quite good at math for a drop out and I love physics as a hobby. I even read "The Elegant Universe" in prison. Keep it coming, sir.
Same.
This is mind-blowingly cool and illuminating. I'd love to hear about more sorts and applications of quasiparticles in Space Time!
In the same way you can have superfluids, when the fluid particles group up into "bosonic sects" and after that they just ignore everything outside their group (just like in real life sects), and the fuid becomes frctionless. Also there is the cool concept of high speed electronics, when the electrons are robbed of 1 dimension of movement (2 dimension electron gas) and forced into lattices, which limits their quantum states, also making it more easier to form quasy-bosonic groups. The whole concept of real life particles playing MMORPG to "pretend" to be imaginary particles and as such taking on new skills and perks is just hilariosly funny!
Awesome work with this video! Another cool thing: when Cooper pairs are formed, they release a phonon with an energy of roughly 2 times the superconducting energy gap. These phonons can actually smash into another Cooper pair and split it back into two quasiparticles. This is currently one of the major obstacles in superconducting quantum computing.
High energy phonons can also be generated from cosmic events like gamma rays. Some research teams are burying their quantum computers several klicks underground and shielding them with lead bricks to reduce Cooper pair splitting due to high energy particles. The craziest thing? It actually seems to be working; the underground qubits are coherent for far longer than those studied topside.
In silicon semiconductors, holes move about half as fast as electrons. To compensate for this, the conduction channels in PFETs are typically made wider compared to NFETs in the same position. Now, this doesn't strictly have to be the case, but it makes rise times slow compared to fall times, and this complicates computing static timing analysis. It's easier if a logic gate of a given type can be modeled as having the same speed whether its output is rising or falling. You could just model the gate's speed based on the slower of the two edges, but then that means your faster transistors are burning more energy than necessary for a given switching speed, and power dissipation and energy consumption are first-class concerns in modern large scale semiconductors, so you either want to size up the slower transistors or size down the unnecessarily fast ones.
Why do electron-holes move slower than electrons? I would expect them to move with the exact same speed - but what do I know about semiconductors... 🙄
@@jespermikkelsen7553 I'm not sure about the physics. Thus is just what semiconductor engineers tell me.
@@jespermikkelsen7553 It's little like blowing wind. Molecules of air just move a little and just carry the force(charge in case of electrons) to next molecule
==>
Everything works in "local scale" but if you earlier WIRE the thing it will create electricity on both ends simultaneously (similar to "violating" speed of lightning by pointing super powerfull laser into moon and fast turning around self, you will artificially make speed faster than speed of light but actually not speed of causality). Sorry, it's probably not the clearest explanation and it's not answering "why" question part
¯\_(ツ)_/¯
This is awesome! I wish I had this exact explanation available 30 years ago, when I was trying to learn the meaning of NP semiconductors. Thank you for another amazing video!
Worked with electronics for years, and this finally helped this phenomenon fully click. Great work, as always.
This episode was the best explanation of cooper pairs I've ever seen. Bringing in phonons to explain the how of cooper pairs makes this all add up a lot better. Also, clarifying they aren't really being pair-like, they all just flow together, also allows me to better understand the steady state environment of superconductivity.
Electrical engineer here, adding a little bit: when we talk about electrons in a crystal usually we refer to a quasi-particle that behaves like electron but has a different "effective" mass. This effective mass can change depending on the energy of the electron - which leads to some interesting properties. For example, in some materials - a high enough energy of the electron can lead it to have a lower effective mass (shifts it to a different valley in the E-k diagram).
Four years of electrical engineering class, and I never heard this explained. Thank you, very well done.
I don't know!
Yes
When?
😮
A summary of my Amazon answers feed
I swear every time I watch an episode of PBS Space Time, a new thing is introduced which completely changes the way I think about reality.
Gonna need a whole spinoff series on quasiparticles now.
1:49 That missing electron up top was killing me, glad the animator fixed it later on 😂 great video!
Glad I wasn’t the only one to notice.
1.Could you please consider making a video showing the idea of the Dirac sea and overall the analogies between behaviors of electrons/holes in crystals and particles/antiparticles in vacuum?
2. Is it possible to build anything like a Standard model for quasiparticles (even though the properties of those are dependent on the medium they are emerging in)?
I like the idea of a "standard model for quasiparticles" but it would be a bit like "classifying all possible songs." Even if there are broad genres there will always be something new that requires a new classification
Add a #3 Any possibility that Quasi-particles might be the source of "dark matter"
@@n-da-bunka2650 they can't be - they are emergent entities. Consider phonons - "particles of sound". They need a material in which they emerge. We would see the material first.
Also - their (quasiparticles in general) mass would have to exceed the mass of the material itself - as there is more dark matter than known matter.
@@falnica I wonder if real particles are also quasiparticles, but in a material that we call spacetime fabric.
@@blinded6502hmm
This is probably like the best video on things I didn't know about science that exists on RUclips to date that I've seen. And I'm going to watch it twice.
The real particles are the friends we made along the way
And the quasi-particles are the friends we almost made along the way
@@sofiamn_05 so quasi-particles are facebook friends?
And the imaginary particles were more real than the real particles.
I mean numbers
@@MNbenMN i guess lol
Me when im trying to understand science
I lost it at college when they said the holes were positive particles. I never realised how deep the rabbit hole goes! Luckily these concepts travel straight through my brain without interacting with my understanding neuron's so I'm not too affected by it all. I just use the billions of transistors in my phone for serious research into cats🤣
I've wondered for a while what a semiconductor is/how it works. It's annoyed me that I could only ever find either technical stuff dense with terms of art or explanations so oversimplified they'd barely work as dictionary definitions. I really didn't expect to finally understand that today but I 1000% appreciate it.
I am a professor at Cow & Apple University. Here, I teach young orang-utans that electrons are planets revolving around their suns (nuclei). And earth is a massive electron around the sun, a massive nuclei. Quantum indeterminacy is decided by small microscopic civilizations inside electrons.
I've studied physics in college and I didn't know any of this. It's amazing how one can always learn new things about nature.
This is easily the best and simplest explanation of cooper pairs I have seen. Well done!
12:45 Phonon-mediated superconductivity (the standard BCS theory) describes Cooper pairs in a singlet state (S = 0). This is required because the spatial part of the wave function is symmetric under exchange of electrons (S-wave) but the whole spin + coordinate wave function needs to acquire a minus sign after the particle exchange to satisfy Pauli's exclusion principle, so you need S = 0. Adding up the angular momenta of two spin-1/2 particles you can either get S = 0 or S = 1, so theoretically you CAN have triplet superconductivity. To this date I don't think they have found any conclusive evidence of triplet (S = 1, p-wave) superconductivity. There are some very specific platforms like Josephson junctions with ferromagnetic barriers that can magnetically align the spins of the Cooper pairs leading to the coexistence of singlet and triplet superconductivity aided by spin-orbit coupling, but "standard" superconductors (e.g. excluding high-temperature ones) have zero-spin Cooper pairs.
Great video! As someone who works in the semiconductor industry and used to grow silicon rods it makes me happy to see doping explained. Lol
So great! Now I can send this video to people who ask me about my research!
Without exaggeration I say to you: these videos enrich my life
I was an undergraduate taking a materials chemistry course when I learned about holes. I accepted the course material enough to do well on exams, but I rejected what I learned about the models because it didn't line up with my ignorant worldview. I don't have a resolution for the layperson's misunderstanding of science - other than a combination of time, humility, and education (more PBS Spacetime).
We need science educators to start schooling the the intuitions of students to the modern perspective that quantum is not weird, it is classical limits and smoothness that is a weird fiction. You can't get infinitesmally smaller than the Planck limit. We need to outgrow the easy metaphors of earlier eras. Sunsets are celestial motion of the earth, not of the sun moving downwards. Timezones are simultaneously different across the world, and time dilates to a moving observer. Quantum effects are macroscopic too, like semiconductor band gaps, the quantum tunneling and fusion behind sunlight, maybe even photosynthesis.
@@fbkintanar "quantum effects are macroscopic too"
Bose-Einstein condensates, everyone. When a macroscopic system starts acting like a singular wavefunction, then that's our cue to curl into the fetal position and accept that we occupy an infinitesimal sliver of spacetime.
Please read the above with the appropriate O'Dowdian cadence.
THANK YOU. I tried looking up cooper pairs a few times, and this is the first time anything about them has stuck.
I'm a Chemist. I died slightly inside when the atomic symbol for boron was written and "Bo" rather than the actual symbol, "B". Physicists....sigh....
My brain hurts too. Don't feel alone 😑
Boronium? 😸
All I know is Br and Ba from some TV show.
@@rheticus5198 💀
Does it “help” that my electrical engineering teacher did the same mistake over a decade ago lol
PBS Space Time never fails at reminding me how much I should have listened in school
I learnt about cooper pairs in high school physics, and now to finally understand what exactly they are and how they work is incredible!
My high school physics ap class was taught by a person who thought your mass changed on the moon but your weight stayed the same.
Needless to say, I didn't learn much in that class.
@@ax14pz107 So that person mixed up the words? Strange, as everybody knows weight is what you determined with scales, and mass is what opposes your efforts to accelerate something. And we've seen astronauts hopping about on the moon. Either your teacher was incredibly dumb, or they just had a case of word-swap aphasia.
This video is my 2022 highlight! It just solved a dozen 'wait but why' moments I had in the past. ♥
Can't wai for an episode on the recent quantum wormhole simulation experiment trying to explain quantum entanglement!!
Per Sabine (another youtube scientist), it was all hype, and her breakdown seemed accurate. Kinda doubt Matt will do a specific episode on it.
This is probably the best spacetime episode yet!
Wow, this is the best episode yet and one of the best science videos I've seen. Such a simple concept that also helps to understand what regular particles "are" and yet I've never seen it explained in so approachable way. Thank you.
Without PBS Space Time life would be more dull 🥰
Fantastic video, I was thinking recently about how superconductivity works and that I have to look into it sometime and I really did not expect to learn that from a new perspective going into this video. Thank you!
i have a degree in Software Dev and work in IT. Ive been in the computer industry for 10 years.
For the first time I FINALLY understand why transistors work. Holy cow thank you so much
Well, now I have some idea of what a quasiparticle is, why we “created” them, and have some understanding of phonons and cooper pairs, which I’ve heard of many times but didn’t know what they actually represented.
The roton is completely new to me, but then again, superfluidity is relatively new to me, I think the first I heard of it was perhaps 15 years ago.
I love when this channel posts. It’s the one channel that helps me go to sleep. Don’t get me wrong. I love science and all these topics but someone about Matt’s voice really helps me go to sleep. I been using these videos to help me go to sleep for years.
Always loved videos on such topics! Prof. Matt here's a request for you, please look if you can upload some videos on widely discussed theories like loop quantum gravity, etc.
Pretty sure he did a video on this specific topic.
Yeah under the "quantum foam" or something.
This episode for some reason was particularly clear and digestible. I think he’s slowed down his presentation so we can take a moment to comprehend what he’s trying to explain. Good job!
No mention of magnetic monopoles? They seem a great example, as something that's thought impossible in real particles being created experimentally as a quasiparticle. Felix Flicker gave a great Royal Institution talk on them a couple years ago.
This is one of the best channels and Dr Matt has a lot of knowledge in astrophysics and he is one of the best teachers in physics and all the support to the channel and Dr Matt 🙏🤝
Nice! I study semiconductor physics so this was the first video I actually had a decent background in. Lets me gauge the level of depth for the topics I don’t have a background in. The videos always do such a good job of simplifying super complex things. Takes years reading through textbooks and resources to understand it this clearly.
Quasiparticles are one of those things I have a hard time wrapping my head around and untangling conceptually. Thank you for this episode getting me started in that direction; I would definitely enjoy more videos on the subject in the future!
Merry Christmas out there everybody! ✝️🎄
Great video. Sir, you are an excellent science communicator.
I;ve been watching Matt for years, i;ve always had a somewhat piecewise understanding of superconductivity,but found it difficult to really grasp,this is THE BEST explanation i've ever heard,if you read this Matt,i raise my glass to you,thanks mate!!!
These quasiparticle phonons are so similar to photons, it makes me wonder if photons are actually quasiparticles themselves. It's the first way of thinking of them that helps me actually understand the whole particle/wave duality concept.
good thinking!
always important to remember that our current physics is always just a model and that the map is not the territory
Well that would require an Ether that the photons is vibrating through. I think physics dropped that idea 150 years ago.
This is the best content I consume regularly.
Thank you for using the word "phenomenon" correctly. I warms the cockles of my heart.
heh, you really explain things clearly and now I'm sure in it. I learnt this in the school, then in the university, then read a lot working as an engineer and I regret a bit that I did not had such well presented explanation from the beginning!
Thank you for explaining the concept of the Cooper pair. I see science news articles about them all the time but they never say what they are, what produces them, and how they actually cause superconductivity. It might not be a complete explanation but it at least gives one an idea of what's actually going on. That instantly makes this one of my favourite Space Time videos, right up there with the one that tells us how the Higgs field works without that BS about people crowding around celebrities.
Love the increase in condensed matter topics on the channel! Hoping a video on the renormalization group and the Ising model is coming up soon.
One question I have about cooper pairs: given the mass difference between electrons and the nucleons of the lattice and their relative velocities is the picture that electrons are attracted to each other via a build up of positive charge from nucleons accurate? Wouldn't the electrons fly past the nucleons effectively not feeling the pull from the nucleons?
They’ve already done the ising model video a long time ago. And for the cooper pairs, I think it’s actually a long range pairing, on the order of 100 nm so basically the lattice vibration is also that long and the electron doesn’t zip past it as fast
@@anthonyward8805 I don't remember a video on the Ising model. Did they discuss it in terms of the renormalization group and scale invariance? I think it's a nice connection between high energy theory and condensed matter. I'm having trouble finding the video.
Also, I'm still not convinced by that argument. For instance, the most probable pairing of electrons in a Cooper pair if of electrons with opposite wavevectors, for which this physical picture doesn't account for.
You guys are the best source for high quality condensed science, that is truly easy to digest.
It’s funny, at the intro I was like “isn’t that just like electron holes?”, and then you proceeded to spend the first five minutes summarising my first few weeks in electrical engineering class!
I laughed a lot at “mass: yes” for the holes too
But I suppose plenty of people who like physics haven’t also dabbled with electronics :)
I was thinking the same thing. At least when I was in school for electrical engineering, we treated the electron holes at basically the same level as electrons, especially when learning about semiconductors
@@caydjj and of course that goes back to Dirac’s “electron sea”, although in that case the holes were antimatter. But at the time he thought he was using an emergent property of his mathematical model, and only realised it was a real particle later! So it’s not electron holes in the modern sense, but he called it that!
Wow. Things have changed so much since I did physics at school.
Thank you for such an amazing, clear and informative video.
Quasiparticles to me sound like they are the emergent physical activity of physics, it's so cool.
I think what we consider fundamental “particles” or field are actually quasi particles of some underlying field or something.
We use imaginary numbers and such as possibly more than just accounting tricks, and if this is true, then it would make more sense to me that we are not at base level here in our 3 dimensions.
I don’t even understand the concept of time as a dimension, but I keep an open mind
+1 on more on superconductors and why very clever people have spent 30 years trying to figure out Type IIs. Best explanation of semiconductors/superconductors that I have ever seen. thx much
This is mind-boggling for a layman like me, I never realized these could be treated as particles, and it makes sense considering real particles are oscillations too.
I always enjoy your videos. Since I'm a bit of an Astronomy geek/nerd myself I always enjoy learning new things about our Cosmos everyday! Thank you PBS!
This was such a great episode. Learned a lot and even was able to successfully pretend I understood it all :-)
i love spacetime. it is one of my favorite channels on youtube.
love this!!! can we have more about quasiparticles soon please?
Mind blown. This topic deserves and perhaps demands many follow-up episodes to explain and explore it. I am equal parts intrigued and befuddled. Waiting for comprehension...
I spotted a mistake in the information about electrons and holes:
When comparing electrons and holes properties the first time, it is said that mass of the electron is constant and hole's is variable - actually, in crystals both e and h masses are variable! even more, they are direction dependent, if crystalline structure is not cubic. It is due to the fact, that in periodic potentials electrons' mass is derived from relation between energy and momentum (wave vector). The same rule applies to holes - and e and h masses can be different from each other!
To be more specific, this kind of electron is actually a quasiparticle as well.
I didn't truly understand how a diode works until I saw the explanation here. There's a time and place for everything and the time for me to understand the diode has come :)
Maybe we should just start thinking of particles themselves as "things spacetime can do."
The amount of cool things we get from emergent properties blows my mind.
The amount of emergent ideas about stuff on RUclips is awesome.
Finally!!! A new episode.
Wow! This video really stood out for me. I have heard of phonons but never seen them presented in this way!
That is fantastic property of our particles reality to create virtual particles and then virtual reality made of them. And again virtual-level-2 made of virtuals-level-1. (Virtual reality not in computer simulation terms). Ok, the question is: "is it possible, that our REALITY is indeed virtual of some more basic, more real particles?" Can we examine this somehow?
Quasiparticals WOW!! It's just opened up a whole new world to me! thanks space time and cheers matt
When you leave your leafy greens in the freezer too long you get a crystal lettuce.
Work in semiconductor industry. Fantastic explanation-- wish I had this when I was taking Devices in undergrad.
What about polaritons? Really curious about those, since they are used to describe the slowing of light in a medium using QFT.
PS. This holes and Dirac holes I believe as well as phonons are used often in 2D materials, like graphene based materials.
I recommend Xenosium's Channel, He always produce very very good content about modern topic in cond mat, including the one you juts wrote above.
@@luanmartins8068 I can't seem to find it.
@@tommywhite3545 Sorry, I spelled the name wrong, the correct name is Xenosum, please have the link ruclips.net/channel/UCEI6P5v0rJEjj9HYiVmeiuQ
Very good intro to bridging from the practical physical ideas about phenomena in states of parallel coexistence, ie wave-particle packet-envelopment of particular coherence-cohesion sync-duration resonance in quantization objectives inside-outside holographic projection-drawing positioning and condensation presences.., which requires a "double think approach another aspect of language all together. Number Theory and Logarithmic Timing-Spacing in Absolute zero-infinity pure-math reference-framing condensation-coordination wave-packaging.
Good stuff.
When I was at the University studying for my BSEE (Electrical Engineering), we always used "hole" current so we didn't have to tag the minus sign along in every equation. Also the diode symbol and the transistor emitter symbol points in that direction which made it easy to figure out a circuit.
That was a beautiful experience when studying physics: When phonons were first taught, they seemed way more invented, just a specific useful way the describe soundwaves and heat in solid matter. But the more you worked with it, the more you saw that they are so similar to photons, which are also just a useful way the describe the world. The question what is "really exists" in physics can be pragmatically answered: If is makes correct only predictions, it is a real as all the other parts of physics, that make correct predictions.
Excellent, as usual starts so innocently and deep the rabbit hole we go.
I wish you'd been around when I was doing my degree. I never understood phonons. OTOH, this took me back to desperately memorising the statistical justification for treating electron holes as real objects for my finals. Oh, how I love that.
This may be your best video so far and that's saying a lot considering the amazing quality of what you always produce!
Gotten out of the habit watching Space Time video multiple times to get it, after all that cosmology recently. No complaint. This video was an eye opener, never once considered Phonons as anything other than placeholder purely theoretical "particles".
Oh my, this may have been the most informative and amazing PBS Space Time episode ever. I've always struggled with understanding what quasi-particles are, but somehow this video made is so obvious that I can't even remember what I didn't understand.
Apparently you have good self-awareness, implies you may have better understanding than may be apparent. See" "Dunning-Kruger Effect", I suspect you're familiar.
These videos are far better than 99% of pop science stuff out there
I once did an undergraduate experiment on superconductivity. Cooper pairs stayed very elusive during that. This explanation is gold. Only several years later I came into contact with phonons as part of Solid State Physics (Statistical and thermodynamic physics).