 Okay, everybody, hi. Am I audible to everybody? Yeah, okay. All right, so I am gonna talk about quantum behavior, not exactly quantum mechanics. Quantum mechanics is with those nasty equations. Everything apart from the nasty equations is here. So, what I'm planning to do is I'm gonna explain quantum behavior through these experiments called double slit experiment. Some motivation behind this talk. You don't get to see that every day, do we? We don't, right? And that is my idea. Now, quantum mechanics to me is a branch of physics which is sort of still very unknown and also very complicated, even for the experts. So, I've tried my best to make this as simple as possible. And I hope many of you enjoy what exactly I'm talking about. So, what is this exactly, right? Quantum behavior represents the behavior of these extremely tiny particles at the subatomic level. Why do we need to care about them? You have your phones, and each and every time you tell your GPS to get your location and you wanna go from point A to point B, you need to know that quantum mechanics is behind that. And that's basically behind the atomic clock which is out there in the satellites. Another fancy thing, fusion happening in the sun. Four protons combining together to form helium. Now, mind you, protons are basically, they have a positive charge and they're supposed to repel. They combine together. Does that even make sense? So, let's focus on the first part, particles. What are particles? Particles are basically chunks, like a rock, right? They occupy a certain particular space and they're discrete, right? They are individual and in a finite set, you can actually count them too. They also follow a deterministic path. Now, it's, again, based on intuition. You also have mass, you have velocity, so you can figure out where the particle would go through the Newton's laws, right? Then we move on to wave, right? Wave, on the other hand, is continuous. There's no start or end depending on the source, right? So, we have that set. It's a combination of highs and lows. What do you mean by highs and lows? These things go up and down and up and down, the up part is high and the down part is down. No, sorry, yeah. There's another thing called wavelength, which is, that's the worst word, it's the length of the wave. Two highs together is the wavelength. Because it's continuous, you don't know the start and end. Where do we, where do you go? The next thing is that it makes an interference pattern. What exactly does that mean? See about it right now. So, when high and a low wave interact, they get nothing. You get zero. And the constructive interference is when two high waves interact and give an even bigger, higher wave, right? Now, if this wave pattern was over here and there are two sources, you see these white things? Those are the places where there are destructive interference, there's absolutely no intensity at all. And the colored ones, of course, are the constructive ones. So, now that we know about particles and wave, quantum mechanics says that there's a dual nature that can exist as a particle and a wave. What does that really mean? Very unintuitive, right? So, we do this experiment with particles. And in this case, let's say bullets, okay? And the setup is extremely simple. It's a double slit experiment. So, there are two slits, slit one and two. And this is a gun. This is not a great gun. It doesn't have much accuracy. So, the bullets can go anywhere at once, okay? And this is the detector, okay? And the detector will detect the bullets coming to them. And what will happen is that it'll make a sound called click because it's a discrete thing. So, it will automatically register that. What happens when only one of the hole is open? You get a distribution of bullets with this P1, right here. And you can see that the peak of this is corresponding to the position of the hole, right? It makes sense, right? Similar is the case with hole two. And once we have both holes open, you get P1 plus P2. Now, Matt says that if there's an event one where the electron goes from, wait. Particle goes from hole one. And this is the distribution P1 of that. Another event hole two, the distribution P2 is the resulting thing. When both holes are open, you have P1 plus P2. And that's exactly what has happened. Now, once we have mentioned with particles, you come with wave, right? What exactly does that mean? We have a very similar setup. Just that in this case, the detector is gonna measure the intensity because it's not discrete, you know? So, there's a very noisy buzz around if it can take. So, you have a wave that passes through hole one in this case again. And the intensity pattern is pretty similar to what the probability was for the particle behavior, right? Now, we do it with hole two. We get a similar pattern again. What happens when we have both holes open? We form an interference pattern, and that's exactly what we get. Now, I need you guys to know all these things because this was probably the boring part, but now we come to the crux of the situation because now we're gonna do something really awesome. We're gonna do the same experiment with electrons, okay? And there. So, similar setup again. Instead of the gun, we have the electron gun. Now, electrons have mass. They're tiny, but they still have mass. And this sort of seem like particles, don't they? So, we do a similar setup again. Again, the detector is again clicking on its while whenever it detects an electron. We do a similar step, hole one. And this is also familiar. When we put both, there's an interference pattern. Does that make sense? What exactly is this? Yes, that was just for the emphasis. So, let's analyze this for a bit, right? Electrons are particles. And if they're particles, they're supposed to, this P12 was supposed to be P1 plus P2. That's not the case. Why? Are they behaving like waves here? Are the particles dividing into two and somehow doing some nasty things here to make it a little bit too wave? Let's find out. Let's measure this. So, we're gonna do this experiment one more time. Similar setup. But in this case, we have a sensor. And a sensor is light-based, okay? So, it's gonna see which hole the electron goes from either hole one or hole two. And each and every time it detects an electron, there's gonna be a flash, okay? So, what we see next with the individual holes are pretty intuitive, there's nothing much. But now when we have both holes open, see the same electron distribution as this. Now it's certainly behaving like a particle. And we're measuring this. So, is this something wrong? Is this something wrong with the measurement or are we influencing the behavior of the electrons in certain ways? Let's do another smart thing. Let's dim this section. Now, when we dim it, we basically have electrons sometimes being detected and sometimes not, okay? And once that happens, you have a very similar setup. The ones which are seen from this pattern and ones which are not from this pattern. This is something really crazy, right? Now it's, you see it, it's like a game of hide and seek. Or peek-a-boo, right? And each and every time you see it, this is behaving something else and each and every time you don't, the electrons are behaving something like a wave. What does this exactly mean? Right, that. The consequence is, electron is a particle, okay? And what happens in the actual sense is that we at least theorize through quantum mechanics that there's a particular wave function. And the wave goes like this, okay? And if you wanna see that particle, the particle could be anywhere inside this wave. So what this wave represents is the wave probability of you finding that electron, okay? So let's see where the electrons are. It could be here, or here, or here, or here. And obviously the most probable case would be somewhere in the center because that's where the highest probability is right, right? Now let's take something more significant than an electron, something more of a, something of a higher dimension and maybe more awesome than electrons. Me, okay? Yes, thank you. So yeah, so if I had a wave, oh by the way, everybody has a wave. We are all made of these things. And the thing with these waves is that the larger the mass, or the larger the object, the lesser is the wavelength. And as you see, the wavelength describes the probability, right? And this is a shorter wave. So the uncertainty is very less here. So that's why you can see me, but you cannot see an electron. Unless, of course, if you wanna see it as a particle. But anyway. So has physics given up? Everything by far we've done so far is deterministic. Whatever we've seen, we see objects, we feel objects, we know where they are in space. Now things are suddenly probabilistic. And the time you see it, it behaves something completely different. So it has given up in a sense. At least the deterministic part is given up. And we now come to the probability world where nothing is really certain. And therefore the law of quantum mechanics, right? And Richard Feynman famously said, like I think I can safely say that nobody understands quantum mechanics, probably including me. There's again a sense of probability there. So mind you. Yeah. So it was mathematically theorized by this guy. This pretty cool guy, Evan Schrodinger. He probably was not a cat person, but he did some pretty cool stuff with physics, yeah. Now how does it really work? There's no machinery behind this. No one knows from which hole the electron went through or did it pass through the wall or what happened. There's no way to see it because when you see it, it doesn't exist anymore. At least the wave part. So what exactly is happening? What we know is the probability and we can work around with the probabilities, right? And I meant to do that a little earlier than expected, but nonetheless. But it's not so bad, right? Because in the end, even if you have a double slit experiment, you know or rather at least math will tell you that 66% of the electrons will go in the center, right? And you probably don't care about how one single electron travels and so on and so forth. You're probably interested in how 100 electrons in a group travel from point A to point B. And you know that 66% would go there, right? Another cool thing. Now, we know that like in the beginning, I gave an example of the sun and the sun has a fusion, nuclear fusion taking place and it generates enormous amount of energy. And something extremely non-intuitive happens. Protons combine together to form helium atom. Some things that are not meant to be together are together because of quantum mechanics. Now, what happens here is this is the place of the proton, okay? Now imagine these are the walls, okay? And protons are right here as described by the wave function. And wave function is right here, right? And there's a very high probability that you'll find a proton here, right? But you also see these tiny blips on the left-hand side and the right-hand side across the wall. And this is the wall that is separating two protons that acts as a repulsive force. And well, a probability of you finding a proton here is quite high. But then out here, it's one in 10 days apart, 28 chances. That's close to zero. But it happens, right? You feel the sun's rays falling on you. And yeah, and this exists. And this is completely mind-boggling. And to me, this is extremely amazing. And I'm not really sure, if you're not amazed by this, I'm not really sure what can really amaze you. As of this moment, there's one certain thing in this world of uncertainty. My time is probably up. Thank you all for being here. And 15 times for organizers, thank you all for all your help in all the departments, right? And it's time for the questions. Thanks. Thank you, Ramalija. So any questions? Right. Sure. Oh, shit. Why? OK, I'm completely nice to the team. So is it just electrons which behave like this? Or is it also other subatomic particles which would do this? Because, you know, when they do all these experiments with large atoms, they see some particles. What are they looking at? What is colliding? So why can't you see some of them and not see the other? See is, again, because of the sensors. But we'll come to that later. Your first question was the electrons, right? No, there are other particles as well. In fact, there's a type of C60 molecule, full of reins. And it's as big as a sucrose molecule for the biology enthusiasts here. So yeah, this particular thing is, again, a very size effect, because size represents your wave length, the probabilistic wavelength, and hence the uncertainty. And more the uncertainty, the more you sort of behave like a wave, you as in the particles. Great. And does that answer your question yet? OK, great. OK, any other questions? Yes? So we can say, basically, that the wave is actually the particle. We can see it as a particle, because it has some characteristic movements of a particle. Just if we say that these wave packets are actually particles. I'm sorry, I didn't get your question. You must be a physicist, aren't you? So what I'm saying is that why we can say that the wave is actually a particle? I never said that, did I? No, no, no. You said that the wave can see as a particle. No. This is dualism. It works both ways. Particle is a wave, and wave is a particle. OK. Wave packets. Probably talking, like, way out of my league here, because I'm discussing this as a physicist, I guess. So just pause me if I'm incorrect. OK. This is what I understood. Particles are still particles, but the way they interact with oneself and the other ones, and the other particles, is through wave probability. And wave represents the probability part, where it's not really physical as such. It's just pure math, which basically just gives you a chance that, hey, in a given particular area, you'd probably find an electron in the middle, or somewhere in the end, or whatever. OK. So what you're describing is why a particle is a wave, because actually we can only see the opportunity or probability to find the particle. Yes. What you're describing is why a wave is a particle. Why it works both waves. You explain it just from one side. Is a wave a particle? Because that would be something new for me. It could be seen. It could be seen as a particle flow, yes. What do you mean by it could be seen? Well, waves have a... Because when you see it, then the wave doesn't exist. No, it's not like it could be seen with your eyes or something. OK. No. It can be, like, I don't know, damn it, I must improve my German skills. OK. Anyway, we can elaborate more on this. OK, I will explain it. That's just to say something, I don't know, maybe some means. Maybe you should mention the answer kind of principle, and then you should mention that the quantum mechanics is based on quantized. To be honest, that was a part of the presentation, I was sort of nervous and I just skipped it. Sir, with the eyes from this... Yes. We are not distinguished between what's going on. Your presentation about quantum theory and then all the story involved. Quantized stuff and everything. And when you can also do the same with photon, all you say, OK, the photon is a wavelength, but then I can see it as a particle and then I say that the energy can be quantized and then you can divide the particle and then it is observed. Yeah, yeah, that's true. This is another... Yeah, this is another... Yeah. Yeah, I understand. Thanks. Yeah. Anyway, Shijer, what I like the most about your presentation is your positive attitude. I spoke about probabilities, that's nothing positive. But you spoke very positively about... OK. Yeah, you know the world of uncertainty, but we go on, yeah, we never give up. Exactly. So actually my question is, what are you going to do with all this stuff? I'm just going to go home and sit relax and probably have a beer. No, but so I am an avid physics follower. I am not studying physics, but I do things on my own. And to me, sharing knowledge, as you said, is a really important thing. And if I am able to generate even a quantum of interest in this, it will be fantastic, it will be great. Thank you very much, Shijer. Thanks.