Quantum Physics: BOSONS and FERMIONS Explained for Beginners
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- Опубликовано: 5 окт 2024
- Here's how Quantum Physics predicts the existence of Bosons and Fermions - but we also discuss what those words even mean!
Hey everyone! I'm back with a new video, filmed a few weeks before we hit 50k subscribers! Thanks so much for all your support. In this video, I wanted to talk to you about two different kinds of particles, known as Bosons and Fermions. You may have heard of these two classes of particle. For example, a few years ago the Higgs Boson was in the news a lot. This, naturally, is a kind of boson. And you may have heard of a particular kind of fermion known as the electron.
Well the existence of bosons and fermions is predicted by quantum mechanics, if we consider a simple system consisting of two (or more) indistinguishable particles. These particles in our system are not only identical in every way (same mass, same charge, etc.), but they are indistinguishable from each other. This means we cannot label them as particle A, particle B, etc., and track them over time. If we leave our system alone for a while and then come back to it, then we have no way of knowing which particle is which. All we know is that the number of particles in the system beforehand is equal to the number of particles in the system afterwards.
This assumption that our system consists of indistinguishable particles can actually be encoded mathematically. If our particles are to be indistinguishable, then we can imagine labelling them particle A and particle B. But this is only for the purposes of our own calculations. If the particles are really to be indistinguishable, then our system must look the same regardless of whether we have particle A on the left and particle B on the right, or if the two particles have swapped positions - we must have no way of knowing. And if that is the case, then the probability distribution of our system (the probability of finding two particles in two given locations in space) must be the same regardless of whether we have particle A on the left and B on the right, or if they are swapped around. I've made videos in the past about indistinguishable particles, so please do check them out on my channel.
As we see in the video, the probability distribution of our system is very closely linked to the wave function of our system. Specifically, it's linked to the square of the wave function. And so we can equate the squares of the wave functions for a scenario where we have particle A on the left and B on the right, and when they are swapped around.
When we do this, we can then follow some simple mathematics to tell us that for a system like this, we can see two different kinds of wave functions. One where the wave function is unchanged when the two particles are swapped, and the other where the wave function becomes negative when the two particles are swapped. These are two different classes of particle. The system of particles that has its wave function unchanged when particles are exchanged, is known to contain bosons. The system that has its wave function become negative under particle exchange is known to contain fermions.
As it turns out, we have seen many particles that display either bosonic or fermionic behaviour. Bosons can display special behaviours such as Bose-Einstein condensation, while Fermions must obey the Pauli Exclusion Principle. I will make videos about both of these topics in the future, so keep an eye out for them.
Until then, I hope you enjoyed this video. If you did, please leave a thumbs up and subscribe, and head over to my second channel "Parth G's Shenanigans" (here / @_parthmusic ) for some of my original music! Follow me on Instagram @parthvlogs.
Hi friends, thank you so much for your support! I've just made a video discussing SPIN very generally - check it out here: ruclips.net/video/DCrvanB2UWA/видео.html :)
Still unable to understand, why u have so less subscribers. The quality and the knowledge in your videos is outstanding. Best of luck brother you are doing great job. Keep it up..👍👍👍 hope u'll have million subscribers Very soon.
Great video!
So, if matter is Fermions, why is it that when we approach 0K it behaves as a Bose-Einstein condensate? I'm clearly misunderstanding something, and I'm struggling to find out an explanation. I'd be obliged if you could answer my question!
Your videos are amazing, keep it up.
@@SkotoSbyBishoP 2 fermions can behave like 1 boson. to be precise, they are not equivalent in zone but have some properties of motion characteristic of a photon. True, I am not very good at how it works at such a formal level.
More intuitive explanation: the nuclei of the crystal are attracted to the passing electron and "suck in" the next electron. Therefore, they travel as a whole - this is the Cooper pair.
Hi! Nice video)
How is the spin of a particle related to the sign of the wave function?
PS please Like this comment to receive a reply notification
Absolutely fascinating! I've never seen bosons and fermions distinguished in this way before; it made so much sense!
Thanks! Glad you enjoyed the video :D
This is the first time i've heard a clear explanation of bosons and fermions ,thank you so much.
I really wish had found someone like you during my school's days who would've made me fall in love with physics
How glad I am when content like this of yours shows up on my timeline. I've been struggling to understand the bottom line of fermions and bosons, and your way of walking through it was really helpful.👏
Best explaination ever.This is the video I was searching for long time.
I have a Masters in theoretical physics but I still enjoy coming back to some of your videos. The way you describe concepts gives an understanding that the purely mathematical cannot give.
Hey stripey soup! Aahh i want a bot help can u help me regardimg physics .im a major enthusiast of it.
Btw where are u from?
And whats ur real name? Im nikhil patro from india!
Hey thanks for the kind words!
Hey I have a doubt..! If two particles are indistinguishable...how do you classify (know) that electrons swapped there position...and higs bosons didn't...how do you know electrons fall in fermions category,if you can't tell which electron is which..?? Similarly how do you know that higs boson didn't changed there position..and can be classified into Bosons category..
அருமை அண்ணா! எனக்கு ஆங்கிலம் நன்றாக தெறியும் எனக் கூற வியலாது! ஆனால் உங்களது விடயம் புரிதலை ஏற்படுத்துகிறது! 🙏🏾💐💐💐
need different videos, explicitly for Bose-Einstein formula n the Fermi-Dirac one....this could be the next step for understanding...!
Your explanations in quantum physics really impresses me, I specifically like how you described quantum tunneling in your other video. Definitely earned a sub !
I feel this is the clearest possible explanation of bosons and fermions that can possibly exist. But I still don't get it.
As I get it, the particles' names are like naming the different solutions to the wave function. As we do detect, testing the conditions/solutions the theory proposed us, the particles with this or that behavior, we can say that those particles do exist or not.
In another words, the math that describes how fields do behavior (like waves) can point us the way to do physics.
In the Parth's example, he just distinguish two particular particles.
The way I try and internalize it is, there are two broad ways of categorizing subatomic particles that make it very easy to predict the distribution of energies of those particles in your systems.
Bosons, because of what they are, follow the Bose-Einstein distribution, and we see this exact distribution of energies from the light spectrum of our sun- the proportion of all photons that have energy E will be easily predicted under the Bose-Einstein distribution, allowing us to engineer a lot of shenanigans like solar cells since we can account for this.
On the other hand, fermions can be described in a similar way using the Fermi-Dirac distribution. The most immediate use is to describe how electron energy levels are formed, and tells us useful things like why semiconductors can conduct at room temperature but not as absolute 0- because this distribution "smears" at higher temperatures, predicting that some electrons will be energetic enough to exist in the conduction band.
So they are essentially two tools for us to describe and predict the probability that particle p has energy E, depending on what kind of particle p is: boson? Or fermion?
I just went through material that he didn't cover in the video, but I think it's useful to try and keep in mind a more practical picture of bosons and fermions as we discuss them at this level of abstraction.
Quantum mechanics is very beautiful in that all these layers of abstraction play into each other in such and intricate way.
It's really not, this was actually a quite poor explanation. I'm not even sure I would call it an explanation of bosons and fermions at all.
you decribed naturally and purely thank you sir. take care sir God bless you here and hereafter
Love you Parth. I love quantum physics too.
Keep up the great videos. ☮️☮️☮️
I suppose in essence bosons are related to "Force" and fermions are related to "Forms".
Brilliant stuff!
Great video! Also really like the new font. However, for equations, it looks a bit off, I kinda prefer your handwriting in those places :p
Hey thanks so much! Appreciate the feedback, I think you're definitely right :D In the next video I'll do all the equations by hand
You are a pure genius. I can tell you can become as good as Richard Feynman or even better if you put enough effort into teaching physics.
This is too much
@@sauravneogi7024 Okay
The probability density is not psi squared, but psi modulus squared. Psi is in general complex valued. The square of a complex number is, in general, complex and probabilities are real numbers.
There is no difference between identical and indistinguishable particles.
Otherwise, it's a good video and you're doing a good job explaining complex concepts to a general audience.
WOW - that was the best explanation of the difference between Bosons and Fermions I have ever seen... well done!
Your videos are amazing, they make these concepts appear simpler and actually give a good understanding. This is coming from a university student who has a course on QM. Btw , the maths is NOT easy!
You are making every maths involved very simple making the physics very simple!
I was searching for such kind of quality stuff on bosons and fermions for my exams ❤
I just wanted to say that your videos help me so much, I have never really understood fermions and bosons this way before and I think after watching your video, I understood it a bit more
OMG THANKS A LOTTTT!!! The way u explain all these is soooo easy to understanddd!!!
I came infront of this video just meadering in youtube and out of curiosity but surprisingly it helped me in one of my confusions as i was studying quantum physics for my coursework. Thanks a lot...Great content
I feel like spending my time watching your videos. I got a clear picture of this concept in 13. 55 min which I couldn't make it in reading the whole book and the derivations I have been learning day by day.
Thank you! This video was very helpful, sorted out the confusion and questions that arose from my textbook! 😃
I was aware of fermions of bosons before, but this video offered me a whole new perspective!
very helpful
was waiting for such a video
Thanks, Parth! I've always been puzzled about how 'identical' and 'indistinguishable' are not the same. now I know!
It was just awesome. Thank you for this simplified mathematics.
Parth, Very clear & very precise. You are doing great service to Physics community. Should be difficult for you, but could you please slow down the vocal speed a bit ?
Why should he slow down, that's his natural tone. Maybe you should just concentrate more.
Great job. thank you. you occupy all the time half of the screen, while you can omit or reduce it in order to have more room for pictures.
Nice topic. I did not spend my 14 minutes (plus some couple of minutes in understanding the topic) for nothing.
Looking forward for more videos like this.
Thank you! :D
As always, a great explanation of the quantum model that forms the basis of all chemistry and the quantum model of the orbitals where electrons are found. Well done Parth!
A very well outlined format for the scientific method applied to theoretical physics at 5:00 and a very well done video all around. Thanks Parth!
Nice video, simply explained. But I would like to add that ψ is complex. So, the roots would be all numbers of form exp(iθ). The reason only +1 and -1 are roots is that two exchanges lead to nothing.
Crisp and clear explanation. Thank you for the video
this video is gold, you deserve more followers.
An amazing explanation. Thank you.
Very clear and concise
im speechless wtf this blew my mind i fucking love this and have so many questions
Thank you so much Parth for such a beautiful explaination.
Your videos just became more neat...
Keep up the good work
When you follow the full complex maths this is even more of a nice result
Hello Parth, hope you are doing good. Can you tell me the syllabus for a natural science course? When is string theory taught?
@@harshitsharma6039, Hi, Could you plz suggest any materials for me to learn 12th grade and 1st and 2nd year QM courses? Thnx a lot in advance!!! (I'm having a lot of trouble learning them)
@@daiwikdhar6464 what do you mean. Are you taught quantum mechanics at school? Or you just study yourself?
@@jimjim3979 I just Study myself !!! :D (for fun)
@@daiwikdhar6464 me too . I am 10th grade and love physics and even if I eventually follow other paths I will always devote my leisure time on physics mathematics and their integration. BTW, when it comes to tools , I just explore exhaustively for every single video related to the concept of qm . I think devoting time on the maths of qm isn't the clever thing to do because they seem utterly formidable and when you try to thorough comprehend them you may seem somewhat inferior to their intellectual standards. Me myself even as a 10th grader I consider some of the qm maths intelligible but still sometimes it subverts my thirst for knowledge on the topic . You might be more smart than me so you may comprehend even more but still I would recommend just dedication on the concept. It's all that is needed to get the picture and the exuberance which you pursue via qm . But if you want to also study the maths, you can just download apps like Ebookdroid and then download some decent books at no cost . I wish to participate on the astrophysics olympiad so I downloaded a book called fundamental astronomy which I found free. You can respectively download some qm books at free. Actually you can download the book I mentioned before too. Even though it focuses on classical mechanics, it has a lot of qm too like black body radiation (which gave the spark for the consolidation of physics for that matter). You will thoroughly enjoy it for sure. I will tell you if I find decent books on quantum mechanics
You’re a great teacher.
Brilliant explanation. Succinct and comprehensible. THANKS!!!
Supeeeer interesting and super simplified!
I would really like if you could talk about the Euler-Lagrange differential equation and the principle of least action, you can really simplify things!
You are awesome at explaining bro 🙏🏼
You make it very easy and very helpful. with this kind of simple explanation, you can explain Einstein's field equations easily. next time explain Einstein's field equations because quantum physics and general relativity mix together to form the theory of everything.
Next video on Heisenberg uncertainty principle please 🙏🙏
Breathtaking and astonishing , I haven't even thought they were discovered overed by such an easy math 🙃
Thank you , ya are the best professor
You will be a great physicist someday. Thanks for explaining difficult things so simply.
Hi Path,
In one of your video you said that particle spin is a special relativistic effect in quantum mechanics. I’m very curious about that cause no other youtubers are willing to dive this deep into quantum physics. So I really hope you could make a video that elaborate on that point a little further.
Thanks!
When you realise that the statistics surrounding bosons and fermions are the reason why photovoltaics works the way it does, it's really quite transcendental. One describes the energies we get from the sun, the other describes how energetic the electrons in the solar cell are.
Unfortunately when you combine them together, they tell you that your solar cell will never be more that ~33% efficient if there's only one absorber layer 😭
This Channel is an awesome new discovery for me!
with every video, if possible, can you provide some links for good and short notes or any book?
Best explanation ever. love you.
What exacly is a negative probabily
Love the video :)
I m from portugal by the way
Psi is the probability amplitude, the actual probability is given by Psi squared, so probability is actually never negative.
@@MrNerdpwn because we always square at the end...thanks :)
Very useful video. Can you give examples of bosons and fermions???
How can we distinguish particles between fermions and bosons??
Why is the square of the wave function telling us the probability distribution and not the normal wave function?
Fantabulous Sir. Thank you.
I love this type of video. Understandable for everyone.
Could you make a video explaining why there is a loophole to this argument in 2D and what is the intuition behind the existence of anyons
Wow! You just made my love for Physics return.
First of all thank you very much for explaining things in very simple manner. Please make a video on Einstein’s famous equation E=mc^2. Thank you 😊
Jahpna tu shi great ho 🙏🙏😍
Love your videos. I was surprised you didn't go the next step and explain the Pauli Exclusion principle. That you could have a BE condensation can be understood by undergraduates (low enough temp and all particles go to lowest state). But its still unclear how anti-symmetric wave fcts give Pauli Exclusion principle
I am an 9th grader , still watching this video and believe me i understood atleast something (not everything cuz i don't have any idea of QP , but still ! )
Your explanation was very good , than you 😀
Same here. It was great
You are yet to learn calculus. So shut up
@@ujjalmajumdar618 why so rude ? I just said that even a moron like me understood his video , this implies his explanation was great
I'd love to hear you explain this on the basis of information or infons.
Great! Please make a video about quantum statistical mechanics
Brilliant Parth. Why don't you try explaining about Quantum Parallelism?
Great video man, the first video I stumble upon from you, easy to understand and I like how you explain it, keep it up ❤️❤️❤️
Sir... We are gonna have words... The day we meet. Brilliant!
I suggest a video on deriving the gouy chapman theory.
wowwwwww ........ i love your teaching , its amazing , it made so much sense , go ahead , if feynaman was alive , he would be proud of you :) ... love from india
*Love your videos and hey that hairstyle is epic*
Hahah thank you, quarantine is bringing out some interesting hairstyles
You've changed font/writing style in the thumbnail :-) I liked the prev one though.
At the same time as explaining us about this cool stuff, are you also using the feynman technique for yourself?
Please make video on Bose-Einstein Condensate...
hey ur the best explainer of physics even then professors!!!
You earned my like and I am already a subscriber
I understand that Psi(r1,r2)=-Psi(r2,r1) (i.e. the equation for fermions) implies that two fermions cannot be at the same place at the same time, which is basically the Pauli exclusion principle. But then it turns out that two electrons can, as long as they have oppsite spins. Well ok, that's because the opposite spin is what makes them distinguishable, so the exclusion only applies to two electrons with the same spin. But why are there exactly two "kinds" of electrons (i.e. two possible values of spin), and how does that relate with the fact that the spin can actually be measured in the three orthogonal dimensions of space etc.... I don't expect you to answer here to all this, I'm wondering if you have a video that clarifies that 😅and how that relates to the indistinguishability thing - or how spin relate to wave functions.....
Errr never mind, it's here: ruclips.net/video/INYZy6_HaQE/видео.html
Thanks for the simple explanation. Are other classes of particles predicted by mathematical symmetries?
This was an amazing video!! Thanks for doing it! Could you please make a video on why psi^2 gives us the probability!
LOVED THE VIDEO
Really love your videos... they're always fascinating...
Plz make a video on quantum field theory ❣️
It would be nice if you could explain in more detail why the swapping of two indistinguishable electrons changes wave function sign.
I'm still looking for an explanation of why fermions are the temporally persistent particles while bosons are temporally transient, and how that relates to their respective wavefunctions. I feel there's an entire dimension of reality being ignored there.
Hii please make a video on which resources to use to start physics and make the transition to quantum mechanics just for beginners study
it would really help to see the wave fuction in a graphic
Your a great teacher , take care
Quite nice,
It's simple and precise
I can say it was a very clear explanation of how the concept of bosons and fermions comes from math, but... I didn't actually understand what bosons and fermions is, I mean, all we have from this video is an abstraction, but maybe a bit of practical information would be nice, why do we need them, what they do, what difference between them comes from mathematical equation to real life. I hope my words makes sense. Anyway I appreciate your work, it seems as though many people find it useful so maybe it's problem with me
As a general piece of advice... "what something is" in science is always determined by "what something does" or "how that something behaves". A deep philosophical discussion won't get you anywhere. Science is experimental and observational and by those methods we can only determine properties. We are not getting to the "essence of things" as Plato and Aristotle were trying to do. We are making precision measurements of energy, momentum, spin, charge etc. though, something which they can't do in the philosophy department. Combinations of these quantities happen to identify physical objects quite uniquely and that is the power of dealing with object properties, rather than objects. In modern physics "the object" itself loses all meaning in relativistic field theory. Only its physical properties when observed for eternity from infinity have "objective" character, and even that is still observer dependent. If you can't learn to live with that ambiguity, then, I am afraid, physics will never be your friend.
Excellent channel. You got a subscriber
Try to do a video explaining and using the electrochemical potential.
Your font is looking great. I wanted a quantum mechanics from so long. Glad you made one. I'm an Eight grader from India and I would be really thankful if you can make a video on General Relativity. Love your videos. Thank you. 😀
Best of luck for future Physics endeavour Bro😃😃😃. A piece of advice from a 12 Grade Indian Physics Student, In our country's Curriculum takes a huge leap when getting to Class 11 from 10th and suddenly Physics need too much Mathematics .So, work on your mathematics and learn Physics, learn to handle technical stuff from the beginning so that you don't feel overwhelmed when you get in Class 11. It happened with me and I felt I will never be good at Physics but now I am quite good with it. Just thought to tell you this because no one told me this when I was in Class 8 and I want to make sure no Physics enthusiasts ever feel that Physics is too hard for them, never let small failures deter you from greater goals and make sure you study hard and with neverending Curiosity.
Best of luck Bro😃😃😃
@@Wannabetolkien Thank you for your advice I am a Physics enthusiast of 9th standard, really appreciate it.
@@Wannabetolkien I am a boy, not sis. Signed in with my mother's account coz my phone lags and my mother doesn't really rewire RUclips. I am a BOY.
@@Wannabetolkien If you are in 12th grade then I think u must be using calculus in your physics. Do they teach Relativity in 12th. Let me know pls.
@@pritivarshney2128 Yeah I do use Calculus in Physics but the Physics you'll study for Boards Examination (In School) will not require that much Maths(they intently downgrade the content). From JEE based books, You'll learn real Physics and Problem Solving , they require quite a bit of Calculus. Boards Syllabus doesn't have relativity and even for JEE Syllabus there's a Small Introductory Chapter on Special relativity . That is all the relativity you'll come accross in you High School Journey but you always have an option to do self study. Sorry for the wrong assumption and I am terrible with punctutations too😅😅😅😅
You are one of the best Bro..Thanks for the Video and Is there a chance that you make a video on Heat Flow?
Make a video on solving schrodingers equation please❤
Interesting explanation as every graduate should learn. The wave functions are normally complex formulations - hence the probability functions are always modulus square of the w-functions, i.e. sum of the two complex components of a w-function. Are my assumptions about wave functions correct ?
keep up the good work ..really looking forward to see more of ur videos..👍