MIT 8.04 Quantum Physics I, Spring 2016 View the complete course: ocw.mit.edu/8-04S16 Instructor: Barton Zwiebach License: Creative Commons BY-NC-SA More information at ocw.mit.edu/terms More courses at ocw.mit.edu
Пікірлер: 1 600
@m.raedallulu41665 жыл бұрын
7:00 (When very good physicist are wrong, they are not wrong for silly reasons, but they are wrong for good reasons, and we can learn from their thinking.) I love it!
@eloymarquez47834 жыл бұрын
Booom
@larrykinglk4 жыл бұрын
Love it too. Very inspiring!
@jasonsmith41144 жыл бұрын
When something sounds right but is also actually right, great quotes are made.
@TruMystery4 жыл бұрын
stfu brainlet
@declanwk14 жыл бұрын
Einstein was not saying that QM was wrong, it gives such accurate answers it can't be wrong. He was saying that QM was incomplete. Bohr's dominant personality resulted in history recording that Einstein lost these early arguments in the interpretation of QM but many of the questions he raised are still unanswered and need to be resolved along with incompatibilities between QM and GR.
@andrewchen26734 жыл бұрын
See you all next year when the algorithm brings us back
@MrSpaceCrunk4 жыл бұрын
Andrew Chen Hahaha had to laugh so hard!
@CarlosGomez-lp9zi4 жыл бұрын
Hi bud
@khaledadrani31844 жыл бұрын
It actually did. Interesting.
@gheorghegeorgescu78464 жыл бұрын
I will be reliving this comment in 6 months time again
@kartikrathore57204 жыл бұрын
@@iiwi758 when it was in my recommendation I thought "this is something interesting to watch" But in comment section I had already liked the top 2 comments.
@stm32526 жыл бұрын
gauss hated the name imaginary, because it's confusing.He suggested to use lateral, because the complex number are represented on the lateral axis unlike all other numbers.
@ridovercascade45514 жыл бұрын
He sounds right, but I am not to deep in Algebra to have an opinion. Maybe Imaginary has also some point of truth? The square root of -1 is impossible, so imagine being possible. B times that imaginary square root -1. But sure for me as a student, it would be made me so much clear if it wasn't called imaginary axis.
@Adam-rt2ir4 жыл бұрын
It's impossible in the usual high school restriction to real numbers, but then people starting to study complex numbers complain, because why study something that is impossible/imaginary, it creates a bad approach, not very open minded.
@BlahBlahBlah136234 жыл бұрын
@@ridovercascade4551 'imaginary' numbers are as imaginary as negative numbers.
@roc65964 жыл бұрын
i can be easily defined as the product between to points in a Cartesian plain which is (0;1).(0;1)=(0;-1) looking at an Argand Gauss plain it would look like i.i=-1, so we can basically multiply to real points and obtain minus one
@Jack010104 жыл бұрын
@@ridovercascade4551 Actually imaginary numbers are real, so it's better call them "lateral"
@ramenmondal83423 жыл бұрын
I am not mathematics major. But whenever I watched videos regarding math it brings Peace in heart. I don't know why
@chiranjitray760 Жыл бұрын
That makes you a mathematician
@antoniodiaz1998 Жыл бұрын
That's because mathematics is a gift from god
@ergbudster3333 Жыл бұрын
Change your major. Unless you're physics or stats or social science with stats then you already in place. Continue thinking. Be the genius you were meant to be.
@zTheBigFishz Жыл бұрын
Music of the Spheres...
@suyash-dwivedi Жыл бұрын
Well you feel nostalgia, that's why.
@luismontalvohiroyasu58144 жыл бұрын
Barton Zwiebach is peruvian. He was born and studied school and electical engineering in Lima, Peru. As a peruvian I feel so proud of him.
@felipetoledodiaz19284 жыл бұрын
Que orgullo, saludos desde chile
@mauricioaletz96944 жыл бұрын
Wow, increíble que haya llegado tan lejos!
@umeriqbal54064 жыл бұрын
Peruvian flake cocaine 👍
@dibujodecroquis16844 жыл бұрын
Ya me di cuenta de que su acento al hablar inglés es de hispanohablante, pero ni su nombre ni su apellido son de hispanohablante...
@luismontalvohiroyasu58144 жыл бұрын
@Arriaga Two El Perú es un país compuesto por un crisol de razas: mestizos, nativos, blancos, negros, asiáticos, etc. PERÚ: País de cultura milenaria y de todas las sangres.
@stephenanastasi7484 жыл бұрын
I had to learn this by distance education (1992) before the internet and always struggled. Barton makes it seem so easy. What a fabulous lecturer.
@vahidmirkhani4 жыл бұрын
I clicked because I thought he was a young Harrison Ford. Now I know how complex numbers are crucial part of wavefunctions in quantum.
@eklipsegirl3 жыл бұрын
Who the fuck is that Harrison Ford? Why are people so obsessed with screen clowns and disregard quantum physics? I had to google to know who that guy is and was very disappointed to find out that it's yet another random film actor :(
@omniyambot98763 жыл бұрын
@@eklipsegirl yeah useless actor
@NightmareCourtPictures3 жыл бұрын
@@eklipsegirl Relax. Some of us that like physics, also like movies. In fact some of us like physics because we picked it up from watching movies! Twister was one of the first movies i saw as a kid...I largely believe that this movie alone is one of the things that shaped my entire life to who I am today, being both a filmmaker and a hobbyist physicist.
@melontusk73582 жыл бұрын
@@eklipsegirl chill, mate, nobody's disregarding QM here. As a physics major who minored in other things, I love cinema. "Blade Runner" starring Harrison Ford was a bold film that dared to ask thought-provoking questions. "Interstellar" is another cerebral masterpiece that also deals with existential ideas as well as Theoretical physics, mainly General Relativity and higher dimensions. It truly sparked my interests again and inspired me to retake my Relativity course. Films have influenced many great physicists and engineers in real life, most notably Hyperspace in Superstring Theory and most recently the NASA's warp drive from "Star Trek" by Alcubierre.
@arnabmukherjee61922 жыл бұрын
@@eklipsegirl calm the fuck down you pseudo intellect
@codeisawesome3694 жыл бұрын
If I ever strike it rich, I would love to go to MIT to study physics at leisure with amazing teachers like this...
@VoidFame4 жыл бұрын
Tbh you could just go for free and not get credit. Make friends not money :p
@codeisawesome3694 жыл бұрын
@@VoidFame I'm not from the States, so unfortunately I'll be stopped at the border even though I'm trying to make Friends - because I don't have Money...
@VoidFame4 жыл бұрын
@@codeisawesome369 I see now. It's not an issue of tuition, but an issue of living arrangements. I wish you the best of luck if you decide that is your pursuit.
@codeisawesome3694 жыл бұрын
@@VoidFame Thank you! :-) Have a great week ahead.
@0xDEAD_Inside4 жыл бұрын
@@VoidFame What! You can?
@user-tt2po5wg7n7 ай бұрын
What a great introductory video. The professor is comfortably understandable and thorough.. Fantastic, short introduction to complex numbers and their importance. Thanks for posting!.
@manuelignaciodelgadotalave79588 ай бұрын
As a peruvian I feel proud of Barton, he is the best student of the National Engineering University in Lima Peru
@hugoaraujo3 Жыл бұрын
I am a teacher at the beginning of my career. That was a very inspiring explanation.
@andrealeto997 ай бұрын
you teach in university?
@System_exit2 ай бұрын
Men of curiosity ,we meet again
@shybot1965Ай бұрын
sure
@Avicenna10 Жыл бұрын
Fantastic, short introduction to complex numbers and their importance. Thanks for posting!
@Plzmt Жыл бұрын
Honestly, this was probably the best introduction to quantum mechanics i'ver ever heared. Before you get to this whole superposition shit and stuff, first explaining the fundamental maths behind it, which by all means isnt that hard to not teach it to students. Great job.
@usptact4 жыл бұрын
Very nice short note on complex numbers. A great professor tells you much more than just writing down those dry equations.
@timthompson4684 жыл бұрын
Great video. I’m reading Ruel Churchill’s book on complex numbers and applications. I like his introduction. Instead of starting with the definition of i as the square root of negative one, i is introduced as part of a function that is necessary for certain equations (an ordered pair with certain, somewhat unusual mathematical properties). As, I read it, the fact that it turns out to be the square root of negative one is more a consequence of the definition , rather than the basic definition of i. It’s a subtle point, but that explanation sits better with me. Most modern books start with “i is the square root of negative one,” and that’s harder to get my head around than the more fundamental definition.
@fourier07able4 жыл бұрын
'I' is a solution of the equation: x^2+1=0,so we could take this equation as the generator of imaginary numbers, i.e. the positive square root of '-1' is the imaginary unit i=(0,1), an ordered pair.
@akinyiomer45894 жыл бұрын
This is actually so damn useful. I wish more instructors/professors/reference books approached the more abstract concepts from this perspective, as the majority of learners - particularly those who don't enjoy maths - will have a better chance at getting a complete and thorough understanding.
@xqamii38624 жыл бұрын
most of the reasons it is introduced like this is because it was used by him previously in the lecture, when talking about Motion in 1D, i think. i do agree that it is a good way at looking at i, and complex numbers as a whole instead of just defining it by itself
@TheBeatle494 жыл бұрын
Agreed!
@MGHOoL53 жыл бұрын
Exactly! That's how we should learn: why was a concept created and not 'here is a useful information to remember'. Things must be learned as they arose: out of necessity not possible utility. That's why I find it fascinating to read history which renders the present necessary or in hermeneutics (e.g. psychoanalysis) to grasp things from their fundamentals.
@keen24614 жыл бұрын
When I studied this subject 25 years ago, back on the engineering classes, I remember I got to understand the topic quite well as it was necessary to solve circuits problems. But I never got to use that on the real world, and now it is a "complex" concept for me. Anyway, I hope someday I have the time to brush up on my advanced maths.
@shameelkhan81892 жыл бұрын
Oh jee aspirant!
@YakiOnigiriZoro4 жыл бұрын
I thought that was Harrison Ford in disguise
@camunoz24 жыл бұрын
Yeah right?
@gabor62594 жыл бұрын
Harrison Ford + Benedict Cumberbatch
@pugboi80174 жыл бұрын
ROFL
@MrGetBad4u4 жыл бұрын
Lol I had the same thought "wtf is Harrison Ford doing at MIT????"
@anderson.barcellos4 жыл бұрын
Dude! Tot's! 🤣
@espi33244 жыл бұрын
This brings me back to the good old days of engineering school. Ironically I miss it. I felt so sharp in my mathematical skills.
@afifakimih88234 жыл бұрын
Very pure very clear very quality lecture series on QM and QFT...!❤💜❤
@nathanwalker14243 жыл бұрын
What a great introductory video. The professor is comfortably understandable and thorough.
@puekai4 жыл бұрын
I like his writing, elegant
@EeshwarBalageethavengateswaran4 жыл бұрын
4:24.. yes we can work and get it.. McLaurin's series is one best way to use and prove that e^ix = cos x + i sin x.. U can enjoy proving it bcoz it gives a detailed and satisfying proof. I've done many times.. it's interesting.. 😊😊😊
@mohamedaminechekkouri88903 жыл бұрын
I’m actually an engineer but this is the first time I understand why we really need the complex numbers Thank you sir !
@nyahhbinghi Жыл бұрын
He didn't really get to a full explanation but it was a good start...a couple of identity equations doesn't explain at least for me
@leif1075 Жыл бұрын
EXSCTLY ZHE DIDNT EXPLAIN AT ALL WHY WHY DOES TJE WAVEFUNCTION have imagonary i in there to begin with...it has partly to do with not being bale to have time move backwards but he doesn't get into that at all..
@michaelgoldsmith9359 Жыл бұрын
We don't need complex numbers it's just a simple way of taking into account things which change with regards to the period of sin function, like ac current, or for simplifying manipulations of vectors, which can be done without complex numbers but just in a nightmarishly complex way.
@kuldeepshukla1797 Жыл бұрын
Started with x^2 + 1 =0. People were not used to with these kind of equations
@iamthegreatest3914 Жыл бұрын
Pure Mathematics don't search for Its applications. Pure Mathematicians do mathematics for fun & they get pleasure doing it . For example - Group Theory was Invented for Fun . But later other people found its uses in Computer Science & Quantum Physics
@sungbeomcho36065 жыл бұрын
How couldn't I thumbs on this lecture. Thanks professor
@gauravxsharma4 жыл бұрын
I really love it we need this type of teacher in india because I always think why this is required to study and he had a very clear point of it with examples i love it never in my life i had this my clear view to any chapter a lots of love from india.
@beoptimistic58533 жыл бұрын
kzfaq.info/get/bejne/jrd5ldFjnMqzmnk.html 💐💐
@FunPHYSICZ11 ай бұрын
This is excellent. One of my degrees is in Physics. I have a lot of math in my background. Complex Numbers were a necessary subject in order to do the math. The problem was that the concept of mapping complex numbers to a Cartesian Plane was just presented as a given, with absolutely no explanation why. "That's just the way it is." Dr. Zwiebach does a much better job of presenting the "why" than most professors. But the ultimate understanding for me occurred when I stopped and read the history of Rene' Descartes, one of the greatest mathematicians ever, and the reason we call this plane representation "Cartesian". If you get an understanding of Descartes's thought process and where the concept of Complex numbers comes from, you can think like a mathematician and not just depend on memorization.
@tchevrier11 ай бұрын
complex numbers are fundamental in electrical engineering and pretty much anything that deals with waves because that angle gives you a way to represent the phase of the wave.
@cidorodrigues60874 жыл бұрын
I'm Sido Rodrigues Brazil I really like Quantum Physics Classes. Very important to know quantum physics. Teach everything the universe knows and you gain self-knowledge about everything. Great series of really useful lectures on quantum mechanics. I am also very grateful to MIT OpenCourseWare and Barton Zwiebach... etc...
@xyzct3 жыл бұрын
The most enlightening way to teach complex numbers is to show the student that from N to Z to Q to R to C is merely four different quotient set extensions designed to remove the obstructions to the inverse operations: subtraction, division, logarithms, and root extraction, respectively.
@LarryD-ul3le Жыл бұрын
You mean limits, not logarithms. And you should really continue on to quaternions.
@xyzct Жыл бұрын
@@LarryD-ul3le, no, I do not mean limits. I mean logarithms. And tell me, what obstruction to an algebraic inverse operation did the quotient set extension to form quaternions remove?
@faustdownunder4 жыл бұрын
The "norm" is otherwise also denoted as the magnitude of the complex number vector. May I respectfully add that Z = cos(theta) + i * sin(theta) only if magnitude(Z) = 1. Complex number are used and have been used for a very long time in AC circuit theory. We can indeed very well measure complex numbers by simply measuring amplitude and phase of voltages, currents, field vectors.
@98danielray4 жыл бұрын
he said the unit circle
@lolaalsaadi57084 жыл бұрын
Wow , such an amazing explanation, thanks lot
@rafanifischer31524 жыл бұрын
These are cool studies. The professor has a nice clear-cut way of explaining without overemphasizing the simpler parts of the mathematics.
@thegirlwholovesmaths4 жыл бұрын
Totally agree. Clear and concise. He knows his stuff.
@pandit-jee-bihar4 жыл бұрын
He summed it all up with the statement that "complex number was needed to solve equations". That's it!
@guythat7794 жыл бұрын
That's a shit reason my nigga
@RangerCaptain11A4 жыл бұрын
शास्त्र ध्वनि - Recorded Scriptures right, imaginary numbers are for completeness. that is a huge reason.
@ffggddss4 жыл бұрын
@@RangerCaptain11A Yes, exactly, and that goes deeper than just needing them to solve equations. Complex numbers, "complete" the real numbers, in a strong sense. Even as needing them to solve equations opens the door to their existence. Fred
@pandit-jee-bihar4 жыл бұрын
@@ffggddss 'Complete' or 'Completeness' Is it something empirically defined or more of a feeling ? Does Integer complete whole number ? The reason one part of it is called is called imaginary is because well it's really imaginary and came into being as a notational convenience for mathematicians. It's a great imagination and opens door to solve equations which could not be solved before.
@ffggddss4 жыл бұрын
@@pandit-jee-bihar Well, no, it wasn't meant in any formal sense. And yes, integers (ℤ) could equally well be said to "complete" counting (aka, natural) numbers (ℕ); as do rational numbers (ℚ) for integers; as do real numbers (ℝ) for rationals. And in each case, there's an in-built operation in the original system, that generates the extended one: • subtraction (inverse operation of addition) extends ℕ → ℤ • division (inverse operation of multiplication) extends ℤ → ℚ • limits of convergent sequences extends ℚ → ℝ • exponentiation extends ℝ → ℂ ( [-1]^½ , e.g.) The same could not be said for the quaternions, e.g. Perhaps the most compelling case for complex numbers is that, on the real line, not every differentiable function is analytic; in the complex plane, a function can't be differentiable without being analytic. Basically, in the complex plane, the constraints imposed by differentiability suddenly become much more stringent than those on the real line. Fred
@ezomaruzcategui80 Жыл бұрын
Thanks for the contribution. Make remember My times in Electrical Circuits with Samer Teacher.
@rogerarrick19079 ай бұрын
Oh that was very good. Brought a lot of stuff together nicely.
@richardhall98154 жыл бұрын
I love how the chalk boards move up and down like window sashes.
@andrewlankford96344 жыл бұрын
You know it's MIT when every blackboard moves up and down like a window sash. That's reeel quality there.
@Istaphobic11 ай бұрын
Still not really any closer as to why they're relevant other than describing a result that has no real solution. I've heard they have applications in electrical engineering, but I haven't studied them, sadly. Something I'll have to do in future.
@srinivasg12954 жыл бұрын
Hats of to the instructor.. Amazing brain people have.. So complex
@intellectualplace4 жыл бұрын
Are the fields that may be considered as sub quantum so far from atoms that they propagate the idea of a possibility that essence transirions to existence?
@roughsharkangular20344 жыл бұрын
I clicked because i thought it was harrison ford teaching mit class
@zzzyzzzyzzzyxxx3 жыл бұрын
It is a tragedy that the terms _real_ and _imaginary_ were adopted to classify these numbers since: a) The origin of the terms was actually meant to be used as an insult to certain mathematicians (more in a moment), and b) It confuses students learning math who, through no fault of their own, assume the lay, or common, definition of imaginary, that being something that is “fantasy”, “make-believe” or “made up”, leading to a student’s understandable conclusion: _how can something that “doesn’t exist” be in any way useful? _ Good question! Origin and usefulness to follow, but first . . . . A side track in nomenclature . . . . In physics, there is a fundamental particle called a quark. There are 6 types of quark. These types are called flavors. The flavors of quarks are: up, down, bottom, top, strange and charmed. Why is one strange and the other charmed? Can you really taste them if they are called flavors? Nope - they are just names whose origins come from the imaginations of the physicists involved. (en.wikipedia.org/wiki/Quark#Etymology) *The origin of the terms Real Number and Imaginary Number* In the late 16th to early 17th century, when some mathematicians began developing the idea of the square root of negative numbers, other mathematicians were not too impressed. One prominent mathematician (and naysayer) of the day was Rene Descartes, who wrote, scathingly, "_These people play with their imaginary numbers while we mathematicians work with real numbers_." Herein lies the origin of both terms real and imaginary. Yes, before Descartes remark, the numbers we now call real numbers were not called real numbers by mathematicians, they were just called numbers!
@beoptimistic58533 жыл бұрын
kzfaq.info/get/bejne/jrd5ldFjnMqzmnk.html 💐💐💐
@stephenmorton80172 ай бұрын
interesting as heck.
@souvikdas56624 жыл бұрын
Really awesome explanation of complex nos and necessities in qm
@sneakytweeky76253 жыл бұрын
Awesome teacher he really speaks a story which makes it attractive to listen to Wish my teachers spoke like this
@beoptimistic58533 жыл бұрын
kzfaq.info/get/bejne/jrd5ldFjnMqzmnk.html 💐💐💐
@gokurocks94 жыл бұрын
I took a lesson on complex numbers before I took any trig, Calc. I didn't know you could use i to solve polynomials. That's incredible...
@drania764 жыл бұрын
That’s the correct order of learning mathematics, congratulations. Once the idea that only positive number has a root square has been internalised it really is difficult to understand complex numbers and complex numbers are another level of mathematics and that is a real magic.
@stephenbeck72224 жыл бұрын
The primary purpose of complex numbers in algebra is to solve polynomials. How do you solve x^2+1=0 without i?
@no_more_spamplease5121 Жыл бұрын
@@stephenbeck7222 Yes. Complex numbers were invented to ensure the *closure* property for solving quadratic polynomial equations, ensuring any of them will necessarily have 2 complex roots (which can be real numbers or not).
@stassavchuk3 жыл бұрын
Well, finally, on the 27th year of my life I realized the physical sense of the complex number :)
@spb11793 жыл бұрын
Going to have to watch these lectures, this prof is amazing
@vipuljani60273 жыл бұрын
I am first time meeting with Walter Levin in IIT Bombay and this time I see that professors is no difference between that!!! I love tham very much in this time I am in harverd in us I am very happy too
@Rocket89P13. Жыл бұрын
El legendario Barton de la UNI
@naveenkrupadas63334 жыл бұрын
MIT is MIT. It is always absolute. Thank you, MIT
@beoptimistic58533 жыл бұрын
kzfaq.info/get/bejne/jrd5ldFjnMqzmnk.html 💐💐💐
@peterkiedron894911 ай бұрын
Do not confuse notation with deeper meaning. The equation can stated as a set of two equations of Re and Im parts and complex numbers do not have to be invoked. So, no complex numbers are not necessary but they simplify notation.
@remixex369 Жыл бұрын
I have never taken QM. However, thanks to QM we have a very VERY robust wave propagation theory. One of the most reliable ways to compute synthetic seismograms is through Normal Mode Summation. It saves you a lot of headaches to do this!
@SanderBesselsАй бұрын
Life is complex. It has real and imaginary components.
@jonahansen5 жыл бұрын
Man, this professor is good!
@ihategrammar4 жыл бұрын
AFAIK, in circuit theory, there is a phasor. We apply imaginary number j to know the direction of alternative electric current. (IT students don't use i because it confuses with intensity of current)
@ihategrammar4 жыл бұрын
Let me know if something is weird.
@ilmdost80884 жыл бұрын
Love this, such a nicely interpretate, We really need of such great man as an teacher.
@beoptimistic58533 жыл бұрын
kzfaq.info/get/bejne/jrd5ldFjnMqzmnk.html 💐💐💐
@jadghalayini14467 жыл бұрын
What if we had two numbers z1 and z2 such that z1 != z2 but |z1|^2 = |z2|^2 (trivial example: z1 = 1, z2 = i). If what we're interested in is the norm squared, when it comes to measuring in quantum mechanics, then what is the difference (measurable, perhaps) between z1 and z2? Another property?
@James__1237 жыл бұрын
I remember this being answered in my lecturers last year, but I can't remember the answer :D I'm sure he's going to mention it later in the course
@IgorAherne6 жыл бұрын
I believe it's the "cosine similarity"
@zoltankurti4 жыл бұрын
Good question. The answer is, you can't measure the phase alone. But if it interacts with another system, the phase difference between the two systems can be measured, roughly speaking. The interference pattern of two waves for example will depend on the phase difference of the two waves. And it's similar for all other systems, you will get an interference term in the prediction which depends on the phade difference and can be measured.
@memelsify4 жыл бұрын
Look up Aharnov-Bohm effect.
@zoltankurti4 жыл бұрын
@@memelsify you still need interference to measure this effect, this is not usable to measure the phase of the wave function. You always need interference with another system for that.
@jaacobb1234 жыл бұрын
When you're smart like these professors you can convey as much information speaking slowly as eminem rapping
@dozog4 жыл бұрын
I like your observation. It's about the information density of this prof.'s words. An involved receiver is also a requirement. Eminem videos have more views.
@jaacobb1234 жыл бұрын
@@dozog Exactly, and very true.
@dozog4 жыл бұрын
@@jaacobb123 If the old adagium that repetition is the mother of learning is true, then rappers may still be great teachers.
@Hi_nochai_bye3 жыл бұрын
Such good quality education to millions around the globe... *Claps claps*
@NeoCynic1 Жыл бұрын
Reading Spengler and his explication of the various "mathematics" of different Cultures. This helps
@peterpetigrew28694 жыл бұрын
"GET TO THE CHOPPER !!!" 😂😂😂😂
@StudiesBR4 жыл бұрын
what kind of harrison ford is this?
@tropictom59964 жыл бұрын
The one that is starring in the upcoming math adventure film “Raiders of the Lost Quark”
@novemberalpha60234 жыл бұрын
Indiana Jones at University
@GaganGrewalf0954 жыл бұрын
Imaginary
@tenaciousgirl52017 ай бұрын
Sir, you don't know how grateful i am to you ! May the One True God bless you.
@oprahwinfrey296722 күн бұрын
Historically, there was sequential extension of number fields. The field of natural numbers was extended to the field of integers, then up to the field of rational numbers, then up to the field of real numbers and, at last, up to the field of complex numbers. The complex field thus has a key distinctive feature: It is algebraically closed. Restriction of physical quantities only by the field of real numbers seems logically unsatisfactory since mathematical operations often deduce them from the field of original definition.
@FernandoVinny6 жыл бұрын
Obviously MIT students already know what are Complex Numbers
@MetallicDETHmaiden5 жыл бұрын
you'd be surprised.
@mohittiwari89345 жыл бұрын
Yes
@aperture04 жыл бұрын
@Non sum dignus I had to 'cause it's freaking MIT!!!!
@brandonklein14 жыл бұрын
I agree, but perhaps it is the case that thinking of them in maybe a new more pure way as described by the professor gets some of the clutter and possible confusion about them out of mind.
@smishdws4 жыл бұрын
At my school, introductory mathematics is a prerequisite for quantum mechanics, but I think complex numbers was still very briefly discussed. Always good to quickly put everyone on the same page to follow discussion, and emphasize some important math concepts that will connect to physics concepts later on.
@joefagan93355 жыл бұрын
Well that was begging the question!!!
@claytonbaddley83714 жыл бұрын
Where do I get this MIT big chalk and big erasers?
@Lesser302 Жыл бұрын
🙋🏻♂️ 5:00 are you talking about a block or cube with multiple vectors that when adding pressure or force and calculating the loss or back pressure, like calculating the inside vectors of a dice. Only 1-3-5 connect and everything else is a multiple of a possible angle, direction or distance of vector 💁🏻♂️
@Indic4Zone3 жыл бұрын
i should really stop binge watching science videos when i keep saying "alright just one more yt videos, and i will sleep after this"
@flowerwithamachinegun26923 жыл бұрын
r/iamverysmart ?
@Indic4Zone3 жыл бұрын
@@flowerwithamachinegun2692 nah dude, i'm just wondering why these lectures videos keep appears in my reccommendation, yeah sometimes i do watch 3b1b/blackpenredpen/welch labs/ocw but most of the time, i watches family guy/simpsons/futurama/one piece/the last airbender, i just like to do it, i'm just not very sure why this video keeps appearing in my reccommendation
@AndreaCalaon734 жыл бұрын
I would love to eventually hear about Geometric Algebra ...
@RangerCaptain11A4 жыл бұрын
my professor for that class was romanian. she talked slow like this professor, so it was easy to follow. it was a good class to expand your mind.
@AndreaCalaon734 жыл бұрын
@Muhammad Haider No, I mean "Geometric Algebra", as proposed and first studied by David Hestenes
@abdellh80793 жыл бұрын
May you give me the answer, I have question, any point have the complex plan and the real plan , than ( we said in the complex plan the reel number a equal |x*+y*| , * is the power 2
@fethilakhdari10786 ай бұрын
Great video in every respect, please keep them comming.
@plfreeman1113 жыл бұрын
A great professor hints at things beyond what are being taught. @2:30, "It's actually zz*, a very fundamental equation". And with year's of math under my belt now, I'm like, "Oh, man, that is a huge deal." That you can use the multiplication of a complex number with it's conjugate to get a real number that is a squared norm and generates a measure on the space of C. Mind still blown (even though I know this stuff well). But the professor just moves on and leaves it lying there. Quietly acknowledging the importance, but knowing that it's a distraction from what needs to be taught. Bravo.
@pre-universitygeometricalg5862 Жыл бұрын
In Geometric Algebra (which is a development of Clifford Algebra), the unit imaginary is given a geometric interpretation that is extremely useful in formulating and solving mathematical problems that arise in a broad range of fields, including quantum mechanics. Our channel is mainly for lower-level users of GA, but some of the members of our associated LinkedIn group are GA experts, and will be happy to direct interested viewers to sources of additional information.
@MikeDbean4204 жыл бұрын
Great teacher. Thank you for video.
@dongkengdiponegoro89004 жыл бұрын
What does black boad name? The bleck board can move/slid.
@williamsmith42204 жыл бұрын
He just derived de moivre's theorem!!! Holy cow I never noticed that.
@puru18184 жыл бұрын
No, he didn't...
@SuperSaltyFries4 жыл бұрын
He derived Euler's formula.
@p27kushagra4 жыл бұрын
@@SuperSaltyFries He derived nothing. What's wrong with u people..?
@emmanuelb.jankpolo46516 жыл бұрын
Great teaching
@Alpha-wj9hb3 жыл бұрын
الراجل ده عالي فشخ ❤️
@nizarsurche4 жыл бұрын
شكرا على التقديم الرائع
@ffggddss4 жыл бұрын
This is really well presented! This guy ought to be teaching at MIT or the like. Oh, wait, ... Fred
@amitabhbasu65834 жыл бұрын
Flfoilm
@oldguy1958hk3 жыл бұрын
Good refreshing course... I make living on I... I call it "j" part of a number ...for me I stands for current, I m an electrical engineer.
@davjdprjce3 жыл бұрын
the imaginary unit is denoted *j* in electrical engineering since *i* denotes current
@jasonsmith41144 жыл бұрын
I thought I was going to sleep, and here I am watching Harrison Ford talking about the importance of complex numbers in quantum mechanics. Sometimes life is strange
@pietro52662 ай бұрын
Because of this lecture, I now understand the foundation of cos x + i sin x, and also how "i" came to exist and it's usefulness. Never saw these explanations before.
@lepidoptera9337Ай бұрын
In a rational K-12 education system this would be 10th or 11th grade material, latest.
@Tomahawk19994 жыл бұрын
if i had teachers like these, maybe i would not have hated math so much and actually done well in my life.
@AnimeCritical4 жыл бұрын
Even now it's not too late.
@MaxPower27194 жыл бұрын
Many people who had bad or mediocre teachers turned out really well. Your future lies in your own hands, not in the hands of some teacher. All the tools are available; you choose to pick them up or walk away. If the "1999" part in your name reflects you year or birth, you are a measly 20 years old. Your life has hardly begun. You have all the opportunities ahead of you to "do well" in your life. Or, you know, you could just sulk on in the internet and blame others for not following your hopes and dreams.
@stuartyeo53544 жыл бұрын
Very encouraging :)
@thicclumber57904 жыл бұрын
Tomahawk1999 ur a failure because of urself and nobody else, but sure blame ur teacher if it makes u feel better
@felipeteixeira71694 жыл бұрын
thicc lumber who the fuck are you to judge someone as a failure, though? There are n factors that may cause one to get unmotivated and bad teachers is surely one of them.
@JeffaHensley4 жыл бұрын
Decent lecture, but it begs the question of the title of the video. He just states that they’re necessary, meanders around a few examples of how we’d be lost without imaginary numbers, but other than this necessity for their existence, doesn’t explain them.
@kingk.crimson66334 жыл бұрын
"Other than the necessity for their existence" that is the title of the video
@RangerCaptain11A4 жыл бұрын
probably a 1.5 hour class, so most of the content is missing.
@ramenbroth4 жыл бұрын
You're asking for something that's not within the context of the title of the video...
@madScientist4044 жыл бұрын
the answer to your question lies in Geometric Algebra. The result of the work of Grassmann, Clifford, Hamilton and sort of rediscovered by Hestenes. It gives you a geometric interpretation for the equation i^2= -1. It can be associated with some plane in physical space.
@flumpyhumpy4 жыл бұрын
@4:38 "Complex numbers, you used them in electromagnetism, you sometimes used them in classical mechanics, but you always used them in an _auxiliary_ way. It was not directly relevant because the electric field is real, the position is real, the velocity is real, everything is real. And the _equations_ are real. On the other hand, in quantum mechanics the equation *already has an i* . So in quantum mechanics, psi is a complex number. _Necessary_ . *It has to be* ." This lecture is from a course on quantum mechanics. The title of the video is apposite, concise, and absolutely correct.
@sureshpawar80754 жыл бұрын
Can anyone tell me is complex number important for physics? Plz tell if u know it is request.
@marckarapalli20274 жыл бұрын
The necessity begins at 4.40 in this video. Simple and great.
@beoptimistic58533 жыл бұрын
kzfaq.info/get/bejne/jrd5ldFjnMqzmnk.html 💐💐💐
@Cjnw8 ай бұрын
4:40
@patrickryckman38674 жыл бұрын
Wow Harrison Ford can do anything.
@springdoctor4 жыл бұрын
There is no mystery about imaginary numbers or euhler’s identity. As the exponent of e , the imaginary number causes the radius to rotate counter clockwise around the x, y axis of the unit circle sweeping out out cosine and sine values just as the good professor says. Knowing this, imaginary numbers make perfect sense and e to the i 2pi = 1
@Larry00011 ай бұрын
G.O.A.T. explanation of complex numbers!
@CIOWhitepapers3 жыл бұрын
Would 'potential number' be a better description than imaginary or complex number?
@kylewhitney28903 жыл бұрын
While the smartest of the smart get into schools like MIT, Harvard, etc., I’d love to go there I would sit in on lectures like this for fun.
@TheMounten13 жыл бұрын
If you work hard enough you can get into a good uni in the us with comparable education although you may have a large debt to loans
@CIOWhitepapers3 жыл бұрын
That's what you're doing right now. Many of the big universities have full classes on youtube now and it's quite possible that you'll get more from those courses than the freshmen who pay top dollar to attend in person.
@2002tantry4 жыл бұрын
Does anyone else feels like you understand these things way down in your career and it just went above your head when you were actually learning in college 😂?
@SuperSaltyFries4 жыл бұрын
It's no surprise. We hardly have any time in university to actually read the damn textbook because each professor assigns so many homework assignments each week plus the 3-4 lab reports to complete.
@souravdatta60734 жыл бұрын
All I got is complex numbers are necessary to solve very complex equations ! (I studied Electronic Eng but wanted to see a new approach!)
@dearheart210 ай бұрын
Brings back memories.
@tonypower56254 жыл бұрын
Ummmm Harrison Ford teaching complex numbers...must be his next movie!!!😂😂😂😂
@NLGeebee4 жыл бұрын
Except that i ≠ √-1. By definition i² = -1, so if anything i = ±√-1.
@adrien85723 жыл бұрын
No by definition i=(0,1)
@NLGeebee3 жыл бұрын
Adrien If you mean that the coordinates of z = 0 + i in a complex plane are (0,1) then you are right, but a graphical representation is not equal to the definition.
@adrien85723 жыл бұрын
@@NLGeebee The way complex numbers are built is by defining two operations on the set R^2 : one addition and one multiplication. i is a notation for the couple (0,1) because it is easier two manipulate this notation. It really is just that. You can represent all complex numbers in R^2 because they are just R^2 with two operations !
@NLGeebee3 жыл бұрын
Adrien I believe I was tought that if the complex number z = i, or z = 0 +1i, then that number z is represented in R² as the point (0,1).
@adrien85723 жыл бұрын
@@NLGeebee That is indeed true !
@oliveroshea5765Ай бұрын
nice understated style!
@ema79564 жыл бұрын
my favourite staff.i love maths
@eceakyol58578 ай бұрын
in turkiye we learn the complex numbers in highschool
@jelteverhoeff3 ай бұрын
In NL we learn nothing in highschool
@Shrodinguer43213 ай бұрын
Come and take a look at the moroccann program 😂
@ansupriyadarshi14563 ай бұрын
So do we in India. It’s a fascinating subject when you look back at it. At the time I thought why study when it’s all imaginary 😂
@t_aikutsu3 ай бұрын
In the UK usually people would start to learn it in university, but some people choose to study "further maths", which sees them learning about complex numbers from 16