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Recorded: 2016/10/22 Published: 2017/01/04
Randy tells Jim about the emerging field of Phononics: using quantum particles of heat in materials for information processing in advanced materials.
Notes:
The Review Article that we discussed here.
A reasonable YouTube speech on phononics, Prof Ben Eggleton - Phononics, the next wave.
Discuss on our subreddit.
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Transcript (Rough Draft; Added 2020/07/06)
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09:20:59 So hey Randy. Hey Jeff So did you want to get us started off with some of this stuff about what pulling onyx is what we wanted to talk about fanatics is what we're going to talk about this time, and I think we're going to start off by comparing photonics 09:21:11 with some of the other technologies that we've seen with a lot of times people will talk about technology as if it's one giant edifice of applied science but in reality, there are many technologies around us that we use all the time. 09:21:25 And we know some of these electronics mechanics acoustics chemical engineering nuclear technology. So an onyx is a new arrival on the scene, there's some theoretical work and some basic experimentation that goes back a few decades but it really hasn't 09:21:39 started to gain any traction until maybe the last 10 years or so, maybe a little bit more than that, as material science and our ability to work with manufacturing at a molecular scale has gotten better and better. 09:21:52 So, looks like Electronics has different components. We've got a diode, that controls the electrical current to make so that it only goes in one direction, we've got transistors which created the entire computer revolution that allowed us to control like 09:22:07 a lot of the flow of electricity, using a gate. 09:22:13 On the there's logic circuits. 09:22:17 The there's logic circuits. The researchers working in phone onyx are now working on emulating those same behaviors, but instead of controlling electrical currents. they want to control the flow of vibrations through matter. 09:22:29 And that's what it all comes down to is unlike the electron is the fundamental unit for electronics, the phone on, which is a wave packet of energy that moves through matter is the basis of photonics. 09:22:43 And so how exactly is a fanatic of a setup. I mean, in an electronic device, what you want to do is you want to put a potential difference over something and then the output is correct. 09:22:51 That's right. And exactly the same thing applies with phone onyx because, unlike electrical energy. There aren't too many electrical potentials around us, we there's a tiller current that runs through the earth, it's a very small power. 09:23:07 There's electrical potentials that are very active during a lightning storms. Well, unlike, electronics, like, unlike those electronics, those electrical potentials photonics applies to us to the whole world around us there's thermal heat flows happening 09:23:22 all around us, between our homes and the outside world. In our car engines, and it really everywhere in the world has fallen on energy, because all of the matter around us has a temperature above absolute zero and so it vibrates with photons it's like 09:23:38 photons are like the noise inside matter that we feel is heat so how does the phone on different from a traditional heat wave like please big book was the analytical theory of heat, that's where his magic came from when he did he does this mathematical 09:23:52 magic where he can replicate any function with some of sine wave. In, he proved this with some mathematical magic and he proved this in a book on heat so we already knew, a very very long time ago. 09:24:05 200 years ago, maybe just 150. 09:24:15 Hundred and 50 years ago we knew that there were these waves in matter that were heat and these waves were basically mechanical energy. So, how do these photons differ from those way. 09:24:20 Well the photon is, is just really the building block of those waves right that's the phone ons are the normal modes of vibration inside matter before they all intersect and get super, Super positioned with each other to create a really unintelligible 09:24:36 signal inside matter right. Well, I kind of understood, pronouns to be, how would, how would you put this one on one of these lazy particle, there's this thing where you have this second quantization where you have a lot of things moving around in a harmonic 09:24:49 way. 09:24:50 If you look at those in the right way, you can make them look like particles. So, you can do this with anything that can be represented as a Fourier series. 09:25:00 Right. You can look at it, either as little excitations of energy, little particles, or as these large scale waves in the in this matter so these little displacements, that are harmonic in the material but they're like a pressure way they're like Soundwave 09:25:16 was moving through whoever in fact they're called sound pronouns are called sounds sometimes, researchers. So, so they're this artifice in some way of being able to represent something by employee a series you end up with something like the Schrodinger 09:25:32 equation, which means that you can represent them as little tiny particles, little tiny wave packets, really, that move around in the material. That's what I think of when I think of a phone is this little tiny wave packet of sound. 09:25:48 Yeah, I think that there's a tendency and in some literature that I've read to refer to it is elastic waves because there's a little bit of a difference between a phone on and an acoustic wave in the sense that the phone on has more degrees of freedom, 09:26:00 right, it can be transverse in two different directions and logic longitudinal. And I think that acoustic waves sound waves that we're normally used to thinking of is just through gases that only has the longitudinal aspect right. 09:26:13 I think that's going to be true if you're talking about through a gas but you do often talk about, you would talk about pressure waves to a solid even when you're in a solid, you have all the issues that come with having a regular array of atoms, that 09:26:25 means you have anisotropy is in different directions at least, if you have a regular and upper right right and it's interesting to see how the researchers are trying to harness, those different properties because it makes it harder to generate a technology 09:26:38 that will manipulate phone ons. And so they're looking at things like photonic crystals, which will constrain these vibration modes to just the ones that they want within whatever application that looking to try out, they have to find some very special 09:26:51 crystals, at least according to what we're reading for this. Right, right your average crystal I'll do it you've actually got to make a crystal with a molecular level to be bound just the way you want using just the materials that you want. 09:27:04 And so that all the architecture is custom engineered it's basically like a meta material. Oh, yeah that's that's what I was going to ask you, you know, are these actually meta materials so I mean some of the things I've seen, make it look that way but 09:27:16 they may just have been people using the materials to do it. The models that they use if you look at the appendix of this paper, the models that they use don't look like things that you'd have to have metamaterial to you, the two models that they use 09:27:50 are one, a model that slightly add harmonic so on top of having a square potential, which would be a harmonic potential Hey x squared is the harmonic potential they add on the quarter term the or B x to the fourth power term to the potential, that's what 09:27:52 they're calling the Frankel corner turnover, or sky this in this thing. 09:27:54 The second one they have is something called the fpu lattice and that's got even more people for me pasta one, I would not even going to try to spell that. 09:28:03 Well, it was a three different short names. The middle one is something you eat for dinner. 09:28:09 And then the first one is fer me like Enrico fer me. Yes. And that one is not really a minute material that that particular case seems to. 09:28:19 Oh, I've got them backwards, and the only positive one is the one with the quarter term, the other one is the Frankel corner for all the lattice in the Frankel current role the lattice is the one that mathematically simulates having a substrate. 09:28:35 So this and this is how you actually make a material for processing in the semiconductor industry, for example, right, is that you have a substrate of something which is usually silicon, then you put something else on top, but that substrate left. 09:28:49 That's afraid if it's oxidized that can be very very smooth, but often what you'll do is you'll put a layer of just sold and you'll take that oxide off. 09:28:58 And there are many reasons for this one is to try to get the atoms that you're putting on there in the exact right position that's called EPA taxi, and the other is that a lot of things that you put on something like silicon like that that so excuse me, 09:29:11 things you put on silicon silicon oxide, they'll have occasion issues because there's nothing to stick on, because that's what the oxide does is it basically smooths everything out so you can hook on to it. 09:29:23 In any event, you end up having this scientist soil potential that you put this stuff on. 09:29:28 So either one of those is not really metamaterial, so both of the ways that they put these together are things that are probably actually crew in regular material that you'd actually use so you, you are going to put these things on a substrate, you're 09:29:42 not going to try to have, you know, they're talking about graphene for example but you're probably not going to just have a free floating graphing circuit, because that's going to break, and then you're not going to have a device. 09:29:55 Right. On the other hand, this other one which is the harmonic for most things in the real world are only approximately. 09:30:08 If you had this huge lattice with all sorts of points all over the place you have additional terms in that potential, and those additional terms of that potential are going to end up being, you know these quarter terms and so forth and so on, they're 09:30:16 still going to be restoring forces but these additional terms are going to broaden out the potential well that keeps things in one spot. It does seem like it's a very tricky science to pioneer and one of the ways that that I've enjoyed looking at in studying 09:30:29 this was the way that they create like a macroscopic model, where they might have a series of steel cylinders. 09:30:38 Maybe a couple inches in diameter, embedded in like an elastic rubber, to try to experiment with a way that a acoustic Earth, you know these acoustic waves will pass through the that that um that material. 09:30:54 But the, the, I think the. 09:30:58 The idea is to try to figure out how to manufacture this kind of stuff at the nanoscale well yeah it's very interesting that they're doing this separately nanoscale I think it probably has to be done at nanoscale because of the wavelength of the vibrations 09:31:10 right, possibly, but apparently there's this guy named star who in 1936, built a junction made out of copper and an oxide phase on the other side, and he was able to get this thermal rectifier this thermal diode in a macroscopic system, likely that probably 09:31:29 doesn't do you much good, but he was able to do this, basically with a wire and some, he was able to create a junction that did this, and that's what they're talking about here basically is at a junction. 09:31:40 So when they're talking about these thermal diodes, for example, they're drawing these things out as extended things but really the action is right at the junction between two different kinds of material right they talk about that a little bit in this 09:31:52 colloquium paper, a phone phone onyx manipulating heat flow with electronic analogs and beyond, which came from the reviews of modern physics in 2012. 09:32:03 And they say, towards the conclusions that that's one of the areas that they have to work on is there isn't a good theoretical treatment, a global theoretical treatment of what these interfaces, how these interfaces work. 09:32:19 And so, a lot of it is still very experimental they have to try them out, that could remain for a very long time, even with their ideas and they seem to be doing a pretty good job, it looks like they've actually gotten thermal diode at the nanoscale for 09:32:30 example, and assembled diode, all the thermal diode means or the thermal rectifier. Same idea is that when you have something that's hot on one side and cold on the other, it will have some sort of heat flow between them, which is the same thing that 09:32:45 happens with your wall on a cold night, but if you switch it around so it's cold on one side and hot on the other less heat will flow the opposite direction that will be a barrier there for some reason it's quite interesting that took them a while to 09:32:58 get this to work this way I considering that somebody's already done it at the macro scale, but it makes sense when you're thinking about this in terms of phone right because phones end up having a spectrum in a material. 09:33:11 If you have a really big material, you basically a phone arms of all sorts. But once you start getting down to nanoscale materials, just like any other nanoscale system you start cutting off wavelengths, start cutting off frequencies of the different 09:33:25 possibilities that are actually there. And so you end up with a much more guess crystallized set of possible phone on frequencies, each part of the material. 09:33:35 So if you have that junction, then there may be some frequencies that are shared between the two different materials, and there may be in fact one of the materials ensures all of its frequencies with the other material but the other material has those 09:33:48 extra frequencies that aren't shared well phone on of that frequency of Kronos that wavelength, if it doesn't have a possible frequency and that other material, just bounce off and go back into the original material at that junction, and that's even without 09:34:00 any sort of imperfections or any of the other nastiness that happens in the real world. And that's one of the things that they're experimenting with with the photonic crystals, his band gap engineering, so that they can decide which frequencies will pass 09:34:13 through the material, and I guess in photonic circuit, that'll be an important, important thing to control. Well I think it's very important. Yeah, the way they have this it's important to be able to do that, just to get this thermal rectifier going this 09:34:30 thermal diode. 09:34:41 After you have that thermal diode. However, it looks like they're able to put a couple of these thermal diodes together and build their transistor. And if you have the transistor, the thermal transistor then just like in the real world of electronics, 09:34:48 right. Yeah, if you have a transistor you can build logic and you can build just about anything you want. Yeah, and I've been kind of musing about this today thinking about what it would be like to have a smartphone that was entirely running on phone 09:35:22 rather than electronics. And I was thinking about how well if that was if you had a phone like that you could probably just set it on the radiator to charge it up or leave it in the sun, possibly, I think, in general, you wouldn't have any issues with 09:35:16 that at all. If these things were actually doing something with the transport. The problem that you'd have is getting the thermal gradient, the difference difference between the two edges. 09:35:40 around all the time we just need to find a way to reliably get those gradients and and so that's really where the hard part is and I'm not sure how you're going to be able to do that although you might be able to use one of these energy harvesting methods. 09:35:52 So if you using one of these energy harvesting methods to do something with the electronics which as long as you're going to be using a antenna you're probably going to want to do, then what you're probably going to need to do is you're probably going 09:36:02 to need to fill your book probably going to be able to do is to choose where you pull off those photons, pull out that energy, so that you can power up the electronic parts. 09:36:15 And if you do that, then you'll have that thermal gradient. Well, that's what I'm really excited about is the opportunity to interface, the two different technologies, because every technology is going to have strengths and weak and other and weaknesses 09:36:28 and it seems like photonic technology opens up all kinds of fascinating doors for energy harvesting. 09:36:37 Imagine I mean, with all of the thermal currents and the heat energy around us if there was a way to to exploit that energy, then we would be able to run all our electronic devices and add new functionality to it with photonic technology, good to get 09:36:50 an energy harvesting working at scale, we could actually be integrated into our devices, then we'd be very far along, I'm not really sure how much you can harvest with these things I had an idea, a long time ago about how to do some of these things but 09:37:01 everybody else thought it was BS. And so I didn't pursue it down. Don't listen to them, Jim. Well you have to when they're your advisor. 09:37:10 The biggest question I have with all this is trying to build up a very, very large potential with energy harvesting. And I think that's something that we should we say for a later episode. 09:37:20 That's the worry for me with energy harvesting is not just getting the energy out is getting the energy out, you know, large enough amount to be able to do things with say consumer electronics, rather than to be able to do something like power, a receiver 09:37:36 for a memes circuit, it would be nice, even to be able to power up something so that you could close the loop on say a thermal actuator in a, in a micro electromechanical device. 09:37:49 But, you know, will be even better if you were able to power your computer, off of me and he will sure and with our electronic devices getting ever more efficient. 09:37:56 The energy requirements are dropping. Just as this technology is starting to emerge. And I've been looking at stochastic resonance energy harvesting, which is really fascinating. 09:38:11 You know you can take noise, really, of any kind, especially vibrational noises, and you can extract useful work useful energy out of us, I've used of these by stable systems by inputting a little bit of energy, so that you can multiply that energy, as 09:38:29 long as there's a noise and that you can tune your system to resonate within the right spectrum of that noise, you can actually pull energy out which seems to defy the second law of thermodynamics, but I think there's a non linearity involved that lets 09:38:44 you sort of circumnavigate that. 09:38:47 So, we may see that in our lifetime so that seems like something that's about to start happening is starting to see the systems and. 09:38:56 And what if we could, what if we could use that principle of Stark stochastic resonance energy harvesting at the level of molecular level through some kind of some kind of phone on a crystal device of some kind of solid state device. 09:39:10 So there's an awful lot of heat energy around us to tap into. Yeah, there's quite a bit so I mean it would be interesting to see how all this really works in the long run, but yeah that's another issue, I think we ought to get back to the information 09:39:38 processing aspects that we that we were talking about here in heaven, we have actually no other episode planned on that already. yeah there was some discussion in this colloquium paper about basically making the basic building blocks on the with the, 09:39:38 the goal in mind to having a phone on a computer, yeah yeah i think that's true and and one of those things that I was looking at I think that was something somebody else was looking at, that's basically what they're talking about here because, I mean, 09:39:50 in this paper, they had three things that they wanted to make, they had the thermal rectifier they had the thermal diode, then they also had the thermal transistor and the way the thermal transistor works, instead of to eat as now you have three, and 09:40:04 somehow you manipulate that third one, and that controls the energy flow around things now you have a control of this thermal current. So you can basically turn it on and off it's sort of like a switch. 09:40:16 It was fascinating to read about that it's, it's, it's such a nascent level of development that they're, they don't seem to be anywhere near the level of mastery over these kind of systems that we have over like an electronic transistor. 09:40:32 Right. But they're definitely on the right track and they definitely know how to get there. I mean they show you how they put the dials together, the thermal diodes together, really, it reminds me of sort of the level of detail you get environments lectures 09:40:44 on computation, rather than looking at these things and any of the other levels that I've seen right I've seen many, many things where they're talking about the fundamental aspects of physics of semiconductors, seen many, many things where they talk about 09:40:57 how logic works after he already built it in a computer, they're very, very few places that I've seen like that finds lectures on computation, where they take you from the basic physics through this intermediate level that seems to be left out, which 09:41:12 is, how do you actually build a device out of that basic physics, through the actual device itself and the level of this paper is very much at that same sort of web was five minutes, where these guys aren't telling you how to build a complicated thermal 09:41:24 processor they're not telling you really in too much detail about physics but they're saying, if we have some simple physics, we have the simplified physics, we have this you know one dimensional and harmonic model of material we modify those and harmonic 09:41:39 potentials in slightly different ways on either side of a junction, then we can build these devices at least theoretically, and here are some attempts that people have made to kind of sort of build some of them, and I mean there, there's data here there's 09:41:53 enough data here to say that, you know, these are things that you probably would be able to look at the fourth thing that they've put in here was memory they actually have memory system that they're talking about. 09:42:03 Yeah, that was really intriguing that was able to store information with the thermal circuit. Yeah, so it's not too difficult basically you have to have a place on your circuit, that's insulated when you want it to be insulated. 09:42:16 And, well, basically you end up with two of these diodes coming in and somehow balance out those things so that if you have the current basically going one way, if you if you have if you have this nonlinear going one way you trap all the energy at one 09:42:32 temperature, and you won't lose anything. And if it's going the other way you trap it at another temperature, and it's stuck there but if you're at some temperature in between, it moves off to one side or the other, obviously they generally show. 09:42:43 We right over at that temperature difference and then we right under, and the temperature difference for the high and most states is not very large it's like 10 degrees centigrade about 20 degrees Fahrenheit, it's really not very large with this temperature 09:42:57 differences that they have but it looks quite stable. 09:43:00 Now that's the part that that baffled me, it was why doesn't the memory just dissipate, are they talking about maintaining a constant input of fun on to maintain those temperature differences, or are they saying that you can, you would be able to leave 09:43:14 that sitting on a table without any energy going into it and it would still hold it to memory, the way I understood it was basically that if you equilibrate the two edges two sides, then the flow in will equal to flow out at two different temperatures. 09:43:29 So that sort of is sort of going to depend on how much or how many photons get in from either side of this memory so you have to have two inputs for temperature to get into the memory element in one output. 09:43:43 All right. And if those if those inputs are at the same temperature, then it's going to celebrate one of its to stable temperatures and which one it will depend on basically which one it's closer to, in some version of closer, but to change between them 09:43:56 you have to have a different on those two inputs, you have to have a different temperature difference. So you have to force it out of, out of its position and out of state into a new state in order to change the memory, nice. 09:44:07 It looks like there are four different diodes, basically thermal thermal resistors in this diagram, they've got here, unfortunately they put the diagram on top of a photograph or. 09:44:19 It's an SEM image, but they superimpose it on an SEM image, which makes me not be able to understand either one. 09:44:26 Well just went off for a little clarity sem is scanning electron microscope right. Yeah, physically what I understood was that they've got these two things coming in here with slightly different and harmonica cities. 09:44:39 And so you end up with two of these things that they call the negative differential resistance. do you understand what they meant by a differential resistance. 09:44:47 Well, isn't that, well, that requires an Ambien heat bath right because otherwise you would violate the second law of thermodynamics, as I understand it, so its borrowing energy from its ambient, and the environment. 09:45:01 Right, well I mean something like that's going to have to happen but basically what, what it means is that at a particular temperature, increasing the temperature for a particular temperature difference I should say, reduces the resistance, yeah will 09:45:30 difference you increase the current, but there's a point where by increasing the temperature difference you decrease the curve, and that point is where you have that negative differential resistance, and this is something that you can get in semiconductors 09:45:42 as well. Some things you can get in semiconductor Physics for electrons right for regular electrical current you can do things like this as well. and the very important. 09:45:51 Yeah, they were saying, This is the fundamental principle upon which the thermal diode and everything else is built upon yeah and you need to be able to do this, otherwise you end up having more and more heat current going through there so the current 09:46:07 just being time rate of change of the heat divided by the area of thinking, oh cut that out because nobody wants to hear that sort of model No, I think it's kind of interesting because you something to think about. 09:46:15 So anyways, that that negative differential resistance is very very important for this entire idea in the memory chip they had to have two things with different negative thermal resistance coming into the memory of that sort of the way I understood this 09:46:29 this whole reading this papers, is that you need to get through those things and I assume that you can just have some sort of output that will always be out putting something right because you're always going to have something coming in, which means you're 09:46:40 going to have to always have something going on right so it maintains a constant temperature. It's what's intriguing is to see how the geometry that plays such a key role in the design and effectiveness of these components, like they showed different 09:46:55 scanning electron microscope photographs of nanotubes that had one side were wider or reinforced with a heavier Adam, they had graphene wrapped into a cone shape, or just cut into trapezoidal geometries or carbon nano cones or graphene nano ribbons one 09:47:13 that was wrapped like a Moebius strip, it was just a pure geometry and the chemical properties of the body, the binding properties these materials, they created these effects for controlling the vibrations, it's it's a very visual and you know he's visually 09:47:36 Here's this nascent science where you can actually, you know, see the structures and get an intuitive sense for how the structures are playing a role in the transfer those vibrations. 09:47:47 This was also very strange because this is another place where we see that very famous, you know, again, people are very, very, very loose with this very phase idea, can you tell me about the berry phase idea that you're talking about. 09:48:00 It was very phase is phase accumulation in the wave packet due to whatever quantum mechanical instances you have. That's why it shows up in like topological insulators and things like that ends up being important for the quantum Hall effect, and stuff 09:48:15 like that but you know when people just talk about this very phase, since always in the material as far as I can tell, it's always geometrical in nature. 09:48:23 The first thing I'm thinking about when you say very phase is a phase of matter but it's not a phase of matter it's just an accumulation of phase, because of the, you know, quantum mechanical stuff going on because of the geometry, the geometry is causing 09:48:39 your way function as it reverses around something, the cumulative phase difference in whatever it is that it's accumulated phase differences here I don't really know where that phase is accumulating, I guess it's in the total heat current in quantum mechanics 09:48:54 thing that's accumulating that as a vector potential. I guess that's a different sort of idea, going into it, but still it's the same idea is that if you go around once this movie is this little Moby strip thing, right, this little movie scrapping strip 09:49:07 you go around that once, and you accumulate two pies worth of phase that shouldn't probably be detectable most of the time but does lead to real effects like again it turns into this phone call effect because of this very Phase I guess I think because 09:49:24 of this very phase I'm not completely sure because it's a couple of paragraphs, end up with this effect where these photons which are non charged particles which are not fermion, like an electron they, the second quantum particles will be a completely 09:49:38 different kind of statistics. They both statistics. So there's no reason why they should do anything at all like an electron, they're not charged, they obeyed different physical laws, except when you would have magnetic field on them, they turn. 09:49:54 There's no reason why a phone on to turn into magnetic field in my brain. Right, right. Yeah, it's hard to understand, that's something I'd like to see if we can find something interesting in that and just talk about that at some point in the future. 09:50:08 But still, that's something that's happening because of the geometry in these things and it's something that seems to be important in actually designing some of these things like they're doing this on some sort of organic molecule in one of these examples, 09:50:22 but the geometrical phase that they're talking about looks exactly like some sort of benzene ring or something like that. 09:50:29 Yeah, I'm kind of baffled I don't really understand, there's a diagram in this paper that shows a plane with the hot side in the cold side. And that's what a magnetic field in the y axis, and the heat flow has a preferential direction, that Ben's it from 09:50:47 a 90 degree angle from the hot to the cold, that's this whole effect thing yeah it's baffling like why that direction that doesn't, how can you have a preferred direction if it doesn't have a magnetic field there is electrical field. 09:50:58 Yes, it doesn't have any rationale as far as I can see, for a couple into a magnetic field, because a phone on does not have an electrical charge, so it's not providing an electric current or anything like that. 09:51:10 It's just keep moving through, through the material, but you can bend the heat, that's another thing that might be really really interesting might be able to do wonders for people's bills by building paint out of this stuff, and making the heat circulate 09:51:24 around the room instead of going out through the wall. That's right, yeah I don't have any idea why this would actually be I mean this is something that apparently somebody predicted, long time ago, maybe not a long time ago but many years before it actually 09:51:36 actually came about. So it was in a pair of magnetic dielectric. Right. And the important thing about that is, is that a pair of magnet each atom inside of the, maybe this is how it actually works right so each atom inside of a pyramid is magnetised each 09:51:53 atom and appear a magnet has a magnetic moment, whereas there are other materials called Daya magnets, which do not carry a magnetic moment unless it's induced by a magnetic field, and those working exactly the opposite way so basically add her magnet 09:52:23 be attracted to, to a very strong magnetic field and the diet magnet will be repelled by it, but it has to be a lot stronger than your refrigerator magnet, you know in Florida, they have these giant spinning electromagnets that's how you get a field strong enough to really see an effect on one of these things and you know levitate your 09:52:28 of these things and you know levitate your frogs. Well it looks I'm looking I'm looking at this section right now about this effect and it seems like they're still trying to work it out that there's several competing explanations and one of them is that 09:52:40 this effect derives from the magnetic vector potential in ionic crystal lattices, where the lack of vibration of atoms with an effective charge will experience a Lorenz force. 09:52:49 And there's another one here it says better results from a ramen spin orbit interaction. 09:52:54 I guess there's a spin phone on a coupling that they're still working on to figure out, so I was wrong about that the dielectric part is also important, right so dielectric is basically an insulator. 09:53:05 That's important because otherwise the electrons would carry the heat away, you couldn't tell if the electrons are carrying the heat away then you think would be the things that are bending in the field when they're moving. 09:53:16 Right. So yeah, they, they had a couple of these different things, things here to talk about them in some place they were talking about a ballistic heat effect, you understand what ballistic means in this case, I thought that it just meant sort of like 09:53:29 a photon traveling through space and said it traveled as a as a as a unit as a packet of energy along given vectors that right so ballistic transport basically means that what happens to your phone on in this material for a particular kind of photos, 09:53:44 that when it travels, it hits a spot where the phone on frequency or the phone on wavelength exactly matches the lattice wavelength of your material, so that now it just takes off in a straight line and doesn't scatter off anything, so that's ballistic 09:54:02 transport, unlike what usually happens with an electron, or a phone on which is it scatters off of everything, and so you get sort of a net push in some direction right but it just it's disperses I'm intrigued by this because it made me wonder I wonder 09:54:17 what kind of energy storage capabilities might arise from photonics, you know we we really struggle with electronics. I mean you've got batteries, which are via chemical energy that real limited amount of energy you can store they're just capacitors that 09:54:33 you can temporarily store energy and and maybe, maybe more long term but it's there's still real limits to the energy density, but I wonder if an onyx will give us another way to store energy. 09:54:44 You know, I wonder if there's if there's a way to design maybe like a total phone on a crystal, where the heat energy could just circulate indefinitely without, without dissipating. 09:54:55 There might be a way to do something like that, but I think you'd end up with some issues I think probably the closest thing you're going to see to that is this sort of memory that they're talking about, if they can build this memory, they're already 09:55:09 building something very much like that because it's storing energy in the form of its memory so that memory is staying at one particular temperature, and it's stuck there, you're never going to be able to get something that say, you put something in and 09:55:22 drops away right, or you put something in stays there no matter how much stuff you put in right because soon you'd end up with something that's 700 Kelvin or 8000 Kelvin or 10,000 Kelvin I mean it just things would find a way in but they wouldn't find 09:55:37 a way out. Right, so you'd hit you'd you'd have to at some point have some sort of dissipation thing. Yeah, well that's exactly what's going on in this memory, right this minute this memory element that they've got they've got some way to take that extra 09:55:50 temperature and let it dissipate and then stay at whatever temperature that was so they have something similar to that now may not be optimized for what you want it to do it may be at to lower temperature, but it's just that to lower temperature then 09:56:04 it's just a materials issue, some engineering problem, right, but it is a. 09:56:10 It sounds like you're talking about basically the, the photonic equivalent of a capacitor, because you've got a higher potential on one side than the other. 09:56:19 It's not that different. I think what you're really talking about is something like the photonic equivalent of flash memory. So it's, but it's close enough because coming that's all flash memory really is is a sticky capacity, I don't really know how 09:56:32 flash memory works I've never studied it. 09:56:34 But, and you're the one who worked at it the magnetic storage company right yeah and if you listen to my description so it and understand it, flash memory is not magnetic oh it's not see that's the thing I don't know what flash memory is that's why I 09:56:47 why I wanted to ask you I thought that I thought it was magnetic yeah it's completely electrical in nature, they basically just for a little bit of charge on something and take its ability way to disappear it before they take off the potential that is 09:57:09 a bad, bad, bad description. But, well I'm only looking for a rudimentary understanding so that's that'll do. All right. Okay. But anyway. You're kicking yourself. 09:57:14 Yeah, so that's pretty much what I've what I've got on whatever it was, we were talking about, we're talking about, well, we were talking about the memory, and you're talking about house. 09:57:23 Okay. Oh, you were talking about storing this stuff yeah so. So yeah, that's all I really got I'm using something like this to store energy for very very long period of time, if the memory works, then you'll be able to store energy in some way and I'm 09:57:38 not sure how much. I'm not sure how useful it will be compared to other technologies. And that's something I think we have to think about when we're talking about technologies and something like the phone onyx as a technology, is that not only does it 09:57:51 have to work, not only does it have to do these cool things like you know couple to write photons coupled of light, because I could imagine you could have some kind of a display with a phone onyx right because it couples two photons, there's mechanical 09:58:04 crystals and things. 09:58:06 So, couldn't you make it like some kind of visual display like a monitor using fun onyx, you might be but just like any other technology that you'd want to use with it you would have to be 10 times as good or 10 times cheaper than whatever it is we have. 09:58:20 I mean, but oh yeah i'm not saying to compete, if this stuff works, then that might be viable, I let me think I think the interesting thing here was that the wavelength of the photons are like optical wavelengths. 09:58:38 Well, well, the wavelengths of the photons at optical frequencies are nano skill. 09:58:46 Inside the nano scale size of the photonic wavelength. 09:58:50 Inside the nano scale size of the photonic wavelength, the nano scale size of the photon because the photons got a wavelength of something around 407 hundred nanometers, on the order of the wavelength of most heat, but that actually has a very large way 09:59:22 right, the frequency is what's making things jump up and down, right, the frequency of the change of the electric field is going to cause some sort of change in the molecular vibrations right it's not the wavelength of the thing that's going to do that. 09:59:39 I think I'm going to have to cut this out because I don't remember exactly how it worked well I'm trying to I'm trying to think. I think that an optical light frequency moving through a vacuum has a similar wavelength, to the photonic vibrations in a 09:59:55 solid, because the speed of vibrations through a solid is so much slower. That's something like that yeah it's like 1000, it's like only 1000 meters per second. 10:00:05 Yeah, oh yeah, 300 300 meters per second so i think so I think the wavelength is similar right. Yeah, I just don't remember. Fair enough. I was listening to guy talking it and yeah that's important to remember that makes this important remember. 10:00:21 That's important to remember. And of course I got it all mixed up in my head and I can't remember which one. But isn't that that is that how often mechanical crystals work is that light shines on them. 10:00:30 And because, and they can couple to the crystals, because the crystal oscillate. I would think that would have to be a frequency that's in the frequency spectrum of the material, right, which would mean that it's the frequency that's important, that the 10:00:46 wavelength, the frequency is the energy, not the wavelength. So if you were switching between different yeah so I think if you're coupling at the wavelength level which would mean your wavelengths were the same. 10:01:00 A be switching frequencies and if you're switching frequencies, then you'd be switching energies of the oscillations. So, that would mean best, you would be able to do it one way but not the other way you'd be able to get photon input to the photonic 10:01:11 device without output, but the energy is also going to be affected because you're talking about moving materials with a mass right. So if it dropped the frequency, but it was moving more matter what if the energy still be the same. 10:01:26 I think that's already taken care of in the opponent's. 10:01:30 I think that's already taken care of in the opponent's your colon spectrum already assumes that your atoms have met. So, the photons spectrum will have that frequency, based on the mass of the material, in part, it's going to be much more detailed than 10:01:47 that, because it's a spectrum spectrum with peaks and valleys and things based on lattice constants and stuff like that, but it is going to be based on the material properties of the lattice frequency the frequency match should be the thing that does 10:02:05 the coupling. The wavelength should be the thing that you get for free, but that means that you're going to end up with, probably a much larger, much smaller wavelength of a phone on that is that doesn't make much sense, because the heat wavelengths, 10:02:21 the IR wavelengths are very, very large right infrared wavelength is very, very large, which is where you'd expect most of this fact, actually that's exactly the frequencies that you would not want to operate something like this, right, because we just 10:02:34 create more noise for the system, it would overheat itself right there was something about there were, it seemed to me like there had to be at least three regimes, right where you have a long wavelength regime, a short wavelength regime, and sort of intermediate 10:02:50 wavelength regime so you know if you have that long wavelength regime, there's not really much you can do with phenomena. I've came across, they mentioned at one point, phone on polarity. 10:03:00 They were talking in its they described that as the interaction of optical phone ons with infrared photons. Not really sure what an optical phone on is I guess it would be a phone on with an optical frequency, but I mean would that mean that you'd be 10:03:12 able to see it as light or no you can't you can't see, you can't see it as like, it would have a frequency of light that seems like a really high frequency. 10:03:20 So, but but they're saying that, since that's an interaction, they must have a similar energy level right the infrared photon must be equivalent to an optical phone on. 10:03:28 Yeah, the opposite. So you're so you're right the photons would have a higher frequency, when they interact with light. Let's talk about the technological implications for photonics I think right now there's a company called photonics somewhere in the 10:03:41 states that's manufacturing, some kind of special thermoelectric solid state cooling systems for hospitals and labs and things like that, I guess you can get a really high precision control of your refrigeration system that way. 10:03:57 But there's also some other prospects on the future which I think are really interesting. They mentioned the brownie and motor. At one point, that's interesting. 10:04:06 Isn't that the like a molecular scale motor that gets ratcheted forward I think Fineman might have talked about this. By the by the random vibrations of the material around it. 10:04:18 Yeah, Brownian ratchet. So basically it's something that can move one way or another, I think that's another thing that will be talking about it's really sort of thing where it's really the way that the energy harvesting work so I mean the thermal ratchet 10:04:31 ratchet is something that will really be talking about with the energy harvesting I think that's basically all that is is that if some and I suffer pain in the material, so that you know you can move one way but not the other way. 10:04:45 And that's why, you know, the thermal ratchet or browning ratchet or something like that is the way they talk about it is, that's the way you get energy out of these things right out of you is the that so that that ratchet system is, is the that's the 10:04:59 asymmetry that you introduced to the system so that you can get it to do work for you. Yeah. Wow, that's cool. They also talked about a couple of fascinating ideas I guess this also kind of bridges into the realm of metamaterials but they mentioned heat 10:05:12 cloaks. 10:05:13 Like, I guess it's like an invisibility cloak but in the infrared spectrum. 10:05:19 And in focused heat rays. 10:05:20 So you could coupled, I guess to the atmosphere and send the laser beam of almost a heat energy at something that's kind of creepy it's almost like a, like a Tesla death ray can imagine just cooking somebody from, you know, the distance. 10:05:36 They talked about thermal the insulated buildings with a really high efficient insulators because when onyx is the mastery of that heat energy right so the amount of energy efficiency that you could get would be incredible. 10:05:49 And then there's of course, the transforming of waste heat from industry. 10:05:56 And I guess even like your car engine and things like that directly into electricity, and I is one of the papers mentioned earthquake protection but I think that again that crosses over into the metamaterials because vibrations of that frequency of like 10:06:08 earthquake frequency. 10:06:11 You're going to need a larger scale system right well yeah so would not get into metamaterials because metamaterials are generally very small things. Okay, so metamaterials are generally here you tailor key geometrical objects at the nano scale in, generally, 10:06:30 you know, large arrays, probably not necessarily but generally large arrays of objects so you'd make, say, lots of little nickel seas, or something like that and you embed them in copper, and that would give you some special way of doing something or 10:06:47 other, so earthquake for a building would, would be just a big phone on it component that would basically be band gap engineered, so that the vibrations from an earthquake wouldn't be able to shake the building apart is that right, I guess so. 10:07:01 I mean I yeah I didn't read the applications very much because usually the applications are just anything they can make up to make make it sound like it's applied right it's a little early within this technology to have any idea about where it's going 10:07:14 to head but I guess you're trying to figure out, well, these are plausible directions to go in, because you don't really know until you get there. One of the other things that they mentioned that was interesting was the way that they're experimenting 10:07:24 with manufacturing and MIT was talking about using interference lithography through photosensitive fluids. 10:07:32 I thought that was fascinating. 10:07:40 You get different laser beams intersecting in a plane. And then I guess those that that activates the photo sensitive fluid fluids so that you can very precisely control positioning and thickness of the, the material that condenses out of that fluid mess 10:07:54 sounds pretty cool yeah I guess they've been pioneering that up there, they get to do all the fun stuff at MIT, when they think of all the fun stuff. 10:08:03 Did you Did you see anything else interesting in this when we went over fun onyx. I think we probably hit everything that we really need to hit especially if we're going to visit this at least twice more. 10:08:13 Well thank you so much for going over this with me tonight Jim Fox seems like really interesting new, new technology. yeah it was great. Talk to you again.
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