Lecture 1: Introduction to Superposition

MIT 8.04 Quantum Physics I, Spring 2013
View the complete course: ocw.mit.edu/8-04S13
Instructor: Allan Adams
In this lecture, Prof. Adams discusses a series of thought experiments involving "box apparatus" to illustrate the concepts of uncertainty and superposition, which are central to quantum mechanics. The first ten minutes are devoted to course information.
License: Creative Commons BY-NC-SA
More information at ocw.mit.edu/terms
More courses at ocw.mit.edu

[@zayharper6577]

I've been to 3 universities in the past 15 minutes: MIT, Harvard, and Stanford. You could say I'm something of a genius.

[@BrandonSalas-us8mm]

Penius

[@alexgg1950]

I also feel like that lol

[@jaynabp3661]

That means you watch none of these lectures in their entirety.

[@zayharper6577]

@@jaynabp3661 I can't remember where I said that I did dummy.

[@jaynabp3661]

@@zayharper6577 some things can be inferred even though not said explicitly

[@lecturesbywalterlewin.they9259]

Prof Adams is a great Lecturer! Very enthusiastic, very knowledgeable, with a sense of humor.

[@fr0iler578]

Lectures by Walter Lewin. They will make you ♥ Physics. Hi Dr. Lewin, do you recommend the courses taught by Prof Adam's or Prof Zeibach

[@fabulator2779]

Hello professor! I am big fan of yours

[@EconAtheist]

Definitely! I wish every physics prof I had had been this good.

[@epistte]

@@fabulator2779 Walter Lewin is a physics superstar. I watch those lectures to be entertained as much as to learn something that I might have missed 30 years ago.

[@ankeunruh7364]

...even he draws poor lines while chalk on a blackboard. (Blackboards and chalk are substantial, essential.) Dear cherished Prof. Lewin, this very honest comment of yours tell me, that you belong to us, all of us, hungry for learning what's around. A personal note: I watched your lesson, in which you gave a grain of sand to a student. After that I took paper and pencil to calculate 'uncertainty'. The very first time I did it. It gave me the courage to calculate the range we have to control nuclear power plants - and to learn that this can be understood by almost everyone. Yes, I do believe - we can. Doubts are made for let us burn, as learners, as teachers, which is the same thing.

[@ashimr]

Class begins at 10:30.

[@blake.72503]

Absolute legend thank you

[@baymaniac]

thank you god

[@jaelynn-rosejames9718]

Thank you ❤

[@haumana420]

Legend

[@efraimkent]

sorry, i’m gonna be late. can you take notes?

[@shahedulislam735]

Took a quantum mechanics course from a desi guru who happens to be among the toppers and I gave up thinking I'm not good enough..this guy made me go over 6 lectures in a week and still hungry to go over again....inspiration is the key to make passionate innovators or scientists or teachers...I wish I had them...good luck to all of you lucky ones who gets to be inspired in early days..inspire your little ones too...

[@NuzzywtheWuzzy]

That's the problem I have with my quantum mech course. Solid professor --completely uninspired. The material is very interesting but he is so damn dry...

[@SavannahSunshine49]

❤

[@JackAndTheBeanstalkr]

you're a victim because every university course I ever took all my profs were kind, compassionate, knowledgeable, supportive, and loving....

[@jaimemenapadilla]

This guy fucking loves what he knows, and he wants you to love it too, which is incredibly refreshing.

[@terrymadre9286]

+Jaime Mena So is a nice, refreshing glass of lemonade with just the right amount of ice cubes on a hot summer's day.

[@YouShouldRepeatThat]

+boobboomagoo learning quantum mechanics while drinking lemonade sounds like a perfect way to spend a Summer's day.

[@terrymadre9286]

YouShouldRepeatThat i love you :)

[@YouShouldRepeatThat]

+boobboomagoo I love you too kind stranger. :)

[@115xXzombieXx115]

o.o gem

[@harshitchoudhary5613]

Getting that MIT education without life crushing loans

[@dsaun777]

And without a degree.

[@SaurabhSingh-fe6lj]

@MrComrade but that's true for both sides

[@geromep5383]

@AetherDivision this is inspiring, thank you! Good luck in future

[@thert.hon.thelordnicholson7261]

@Electronification Firstly, it's a fucking joke. Secondly, that's a big fat no - the difference is that a degree demonstrates your ability to apply your learning. It indicates that you've been taught using an established and proven pedagogic method. It indicates that you have benefitted from peer review and peer learning. It means that you have been taught by academics who have also gone through the peer review process and have emerged in a competitive market as some of the best people to teach you. It requires you to produce assessed outputs in the form of papers, assignments, exams, all of which ensure your learning is embedded. It indicates that your learning has been structured in an effective way, building upon foundational knowledge. If you're trying to make a somewhat clumsy point about self-directed learning being as valuable as directed learning, then I agree with that, but don't make the ridiculous suggestion that there are not other tangible and intangible benefits delivered through formal education. It is right and important that learning is delivered to accepted standards, and that's what a degree demonstrates. Perhaps you are one of those people who "study" for 12+ hours a day by literally just reading and annotating books? That is not learning, that is memorisation. Your overly simplistic view shows me that you don't really have a clue about education, probably because you are lacking some yourself. Now, get back to Pornhub ;)

[@yojodingy6334]

@Electronification I can’t tell if you’re trolling or not

[@PotatoGod69]

This is an absolutely great professor. I wish I had professors like him.

[@agrajyadav2951]

You want professors like him, you be smart enough to get into mit

[@tidaimon2149]

We have him now, don't we?

[@Fudge7]

@tidainon2149 yeah 😂

[@denisesoaresdasilva7358]

Me too.

[@denisesoaresdasilva7358]

​@@tidaimon2149More or less for I don't live in the USA and having him only on KZbin is not enough😂

[@tpstrat14]

wow.... we need more professors like him. Most physics and math professors laugh at questions. Like "what are you talking about. That's just a bad question. STFU and let me move on" instead of "what do you mean by that so I can correct your misunderstanding that like 8 other people in the class probably also have" which is clearly how this guy teaches. In other words, he actually teaches.

[@Majoen1998]

32:56 "The miracle is not that electrons behave oddly. The miracle ist that when you take 10^27 electrons, they behave like cheese."

[@sebgamboa7628]

​@@fartreview1739 Nice dude, your statement is exactly what I thought of your comment. A completely empty statement that has no meaning.

[@Joe11Blue]

You just figured that out? He's an ass.

[@goofycker]

'm lookin for a Superposition at MIT. Anybody know some vacant ones?

[@Elaba_]

There might be some holes in that cheese, euh theory.

[@lah5598]

The statement is full of meaning. It implies the existance of emergent phenomena, that is systems that are more than the sum of their parts. This is one theory of where conciouness comes from, one that is not incompatible with the idea of sentient AI life in the future. Emergent phenomena also explain phase changes and why macroscopic systems behave differently than microscopic systems. What are all y'all on about?

[@michaeldavis812]

MIT, thank you for having courses such as "Quantum Physics" uploaded to KZbin for people to learn. As a person that has autism, it is much easier for me to learn in a relaxing environment where there are little to no distractions, and at the pace I want. Keep up the great work!

[@controlaltdemomn9320]

It is a great thing that you are devoting yourself to such an interesting (yet somewhat difficult) topic, especially with autism which seems to hold most back. Even if this is a year old, I hope you get Quantum Mechanics or have a basic understanding of it.

[@abinashsatapathy8394]

awesome

[@neloka4313]

Asperger Autism?

[@neon_necromunda]

I totally agree I have aspergers and find this helps. Ecspecially with Professor Adams easygoing teaching style although I do have one addition id love to do to that experiment.

[@Super-id7bq]

Dude I have ADHD and I was thinking the EXACT same thing! Before KZbin came along my education was horribly sub-standard but through video based educational content I've managed to self-teach myself into a skilled VFX artist working in the film industry! Hooray for KZbin and the educators that choose to share their work! :)

[@xle3blx]

I don't know what the hell Prof. Adams is trying to teach me, but I'm here for it.

[@Oscalishious]

I was quite sucky at physics in high school, but I've always been really fascinated by QM, even though I never really got a full grasp of it. Now having found this video, I'm starting to get the basics and that honestly feels amazing! I've never seen such an enthusiastic and fun prof. as Prof. Adams & am really glad I have the opportunity to listen to him teach! :)

[@serious_filip522]

¨I never really got a full grasp of it¨ Here are some quotes from the greatest Physicists of all time: Quantum mechanics makes absolutely no sense Roger Penrose If it is correct, it signifies the end of physics as a science Albert Einstein I think I can safely say that nobody understands quantum mechanics Richard Feynman If you are not completely confused by quantum mechanics, you do not understand it John Wheeler I do not like it, and I am sorry I ever had anything to do with it Erwin Schrödinger

[@Oscalishious]

@@serious_filip522 Aww, that's actually really reassuring haha. Thanks for sharing, very sweet of u, I hope u have a nice day :)

[@SavannahSunshine49]

​@@serious_filip522yes thank you! ❤

[@LexiNc8284]

@@serious_filip522thank youu!❤

[@LoremLorem]

Hey! Here is some 3D illustrations about the subject: kzbin.info/aero/PLkyBCj4JhHt-80ttR5a_fwtFO4SwDAFld&si=A9QYx-o3rRhTDvP8 Eugenes channel is one of My favourite ones! Btw, If someone smart could find a away to increase brain activity Via magnetic Fields, would it make us smarter or think faster? What about feelings? And If there's anyone good on chemistry, how about creating a drink that would increase endorfines to help us all 😅! What a lovely a idea, to feel great all The Time.

[@LoldemortII]

When he turns to the crowd and asks „Questions?“ Me: Yes, why am I here at 2am?

[@NovaWarrior77]

Right?! Like why does KZbin recommend the most random things at 2am?!

[@ravijangrax]

Not KZbin but boredom brought you here 😄😅

[@argentina.travel]

6:30 am here xd

[@sakkthisundaram7578]

omg same!!

[@raysonlogin]

Same here, staying up at 1:30am to watch this lecture!

[@mercster]

I'm almost as amazed at MIT's complex blackboard system than the quantum superposition of subatomic molecules.

[@OldRacket]

They have blackboard superposition.

[@jacobhatch655]

mercster molecules aren’t subatomic

[@yourlordandsaviouryeesusbe2998]

@@jacobhatch655 he meant particles I presume lol

[@sulaimanalsalem]

mercster xvu

[@imranq9241]

It’s four blackboards layered on top of each other

[@farahfathy3116]

This is the type of professors we need to heal our academic traumas

[@granand]

Prof Adams passion is what kept the students and audience glued

[@TheDiamond2009]

That and the Higgs particle.

[@AkitoLite]

No. You think these students are your average high schooler? No. The best of the best teachers teaching the best of the best students.

[@danlock1]

What a boson! @@TheDiamond2009

[@firstnamelastname6926]

Damn these students are lucky to have such a passionate professor

[@SjarMenace]

And i hot one too!! 😍

[@udoyxyz]

We also have him. So we are lucky too.

[@frankchris07]

they pay for that but MIT professor are amazing. Watch Eric Lander on DNA OMG so good.

[@dirkscholten9995]

No kidding...i loved profs like this back in my university days...direct, encouraging, simplified...i wonder where he is teaching now?

[@milenabaycheva1627]

Bbbbygygbbb 35b 3b bbbbygygbbbb bb bbb3b3b gbg хн3нн3н33ъйнъ@@SjarMenace нbbbbg5gbbebbhbbbhyby3hb b7

[@jamiecfthedrummer]

Heisenberg and Schrodinger are speeding down the highway when a state cop pulls them over. The cop walks up to the window and asks Heisenberg, "Do you know how fast you were going?" Heisenberg replies, "No, but I knew where I was." The cop says, "You were going over 90 miles per hour!" To which Heisenberg replies, "Fine. Now we're lost." Thinking this answer is a little strange, the cop decides to investigate the vehicle. He begins by opening the trunk. Shocked by what he finds, he shouts, "You have a dead cat in here!" Schrodinger answers, "Well I do now!"

[@yiluoli6890]

love this haha

[@GimmeSum]

You are sooooo funny I laughed until i stopped

[@sajateacher]

TwinRocketMedia - um... but there's no speed limit on the Autobahn, lol

[@sherlockholmeslives.1605]

Rene Descartes goes into a sandwich bar and says, "I'll have a chicken bap please." The shop worker says, "I can't serve you that but you may have a turkey baguette." Rene Descartes says "Oh I think not." And disappears. With Best Wishes! Cheers - Mike.

[@duartesilva6824]

You forgot to include Ohm in the backseat... Schrodinger and Heisenberg were arrested, Ohm resisted.

[@mttlsa686]

I'm a 40 year old man, passionate about the understanding of how the universe works and when he said "except you're all wrong" i've got emotional for a moment because it was a kind of illumination giving me an instantaneous sense of awareness to the existence.

[@JackAndTheBeanstalkr]

did you see a tunnel with a white light?

[@mttlsa686]

@@JackAndTheBeanstalkr not yet.

[@kkolxasram]

The most nourishing bit of information in this lecture is at the very end. Our intuition is formed from experience in the macroscopic world, which is totally different from the microscopic quantum world. This explains our frustration with counter intuitive results when trying to understand quantum experiments, since our intuition is not adapted to the quantum domain. Its like learning a new language. Thank you MIT for sharing.

[@gamerN77]

I can't stress enough how much I love the fact that MIT is providing those courses online for free for anyone to watch. Who knew, that a 17 year old German law student like me could get his hands on quantum mechanics lectures of MIT ^^

[@dragonkingmastaman]

Chitown 773 deep breaths buddy we know you're smart too

[@souleater5762]

tbh i dont think he was trying to say "look at me, im so smart" but rather like "yeah im just studying this *not so cool and hard thing* and now i get to watch this hyper cool and indeed complicated stuff, that's a cool opportunity regardless of my intelligence".

[@asmpoohbear4332]

ur not woke unless you take PE

[@PhilthyPhilTheOriginal]

you mad nerd?

[@deathtotruthers1]

Don't be an ass Jordan.

[@Stone2home]

the content starts at 10:33.

[@rabia1180]

+Benjamin Stone now I wish I had read the comments earlier than 33 minutes into the video..

[@TonyDaveYayo]

+Flowers osdfv LoL, that was exactly the time when I started reading the comments :D

[@rabia1180]

TonyDaveYayo hahaha we have the best luck

[@TonyDaveYayo]

Flowers osdfv yeah, but I only watched it because I was bored anyway :D

[@rabia1180]

TonyDaveYayo haha same here tbh

[@fabiorestrepo98]

I just learned Dr. Adams was born in my same city (Bogotá, Colombia). What a pleasant surprise, professor :)

[@chickenliver66660]

I am so very grateful that i have stumbled across this channel. As a person who is only watching these videos for the curiosity that i have towards quantum physics, this has helped me understand the topic and it makes me feel that i am physically sat in the lecture room!. thank you

[@777philgood]

you were there 50% 🤪

[@chickenliver66660]

@@777philgood wdym

[@ayyewalkdaplank]

​@@chickenliver66660Quite possibly a joke made out of the lecture itself with 50% stuff. Like you were there, and at the same time, you weren't.

[@chickenliver66660]

ohh right noow i get it tyty@@ayyewalkdaplank

[@ayyewalkdaplank]

@@chickenliver66660 You're Welcome.

[@jasonchiang251]

he's so passionate about the topic. Really a great professor

[@acershund1]

yes yes yes

[@silasmaurer7835]

absolutely

[@hongluzhang7771]

u can watch his ted talks, also great.

[@alejmitra7483]

11:10 All that is in the table bottle is coffee?. I personally am more passionate / nervous if I take all that. However, great teacher

[@umojaharambee7015]

@@hongluzhang7771 a mkdjkshjdffgg.;(&&, A cg hd😖😢😟cg kjfgjk zsxjfghjj sch A sad ( go 😭😟😢🍹⚾️🛕🏦🏦🏢🍻🍴♊️💝💓gf n

[@BudFieldsPPTS]

As an educator, what I enjoyed most in this presentation was the "buzz" of learning. From the passion and enthusiasm of the lecturer to the engagement of the students, this shows a really awesome lecture. Well done. Very well done.

[@maggotdude667]

+Bud Fields (PPTS) I highly agree. I felt more engaged in the lecture because of that.

[@takashikashiwase3461]

+Bud Fields (PPTS) I know exactly what you talking about,students or human don't like the linear process,he is so damn non linear,this is real process of learning,organic,non linear,beauty

[@mrobusto1010]

+Bud Fields (PPTS) His passion for the topic and teaching it is overflowing, that is certain.

[@Kornflayx89]

I want to find something in my life that I am as passionate about as this teacher is about Quantum Physics

[@SV27]

Dude im basically a house pet when it comes to academics but Dr.Adams' enthusiasm made me watch 3 hours so far. Thanks to MIT for making this available to us lower common denominators!

[@Remslem]

It really strikes me that I've never really had a teacher that's this pumped up just before a lecture. What a great guy!

[@gregoryjwellls]

I concur. This is what engagement looks like. Most professors approach their lectures with a self-requirement that they want to present the information to students in a clear & concise way. This guy wants to create the thrill of curiosity and discovery in his students.

[@jkholtgreve]

Feynman taught similarly. His lectures are naturally quite outdated along the fringes but the basic concepts remain the same and his enthusiasm is utterly infectious. I think they may be some of the lectures this prof was referring to.

[@DimitriosChannel]

He's probably loaded on adderall and caffeine lol.

[@stinkybutt02able]

His passion for his job is adorable.

[@vishaldeka5298]

At this point in my life I can't even sit through a movie and watch them in parts. I just sat through a 1 hr + university lecture on Quantum Physics, of all things and I am a Computer Science student.

[@tmo314]

MIT has the most chill and exciting professors. I’m so happy this is on the internet 😁

[@mescalinemonkey8183]

I wish stuff like this was aired on public tv.

[@epistte]

You and me both. I might support PBS with a few more dollars. We do a very poor job of supporting lifelong learning in the US and that needs to change if we are going to be a technology leader.

[@voldy3565]

Nah, most people are too dumb to understand this.

[@epistte]

@David Roberts Nature and NOVA are some of their most popular broadcasts so I think that they could, but many people have given up on them because of constant reruns of 30-year-old programs.

[@connormartin5053]

that’s free education at the college level america would ever do that

[@asdfghjkldfghjhgcgyuigfyui9792]

99.9999999%+ don’t understand any of this

[@helloimnisha]

This is how a teacher should be. The content, even if rigorous, was still so engaging. I wish my professors were this passionate about physics.

[@resaledragon]

They behave like CHEESE!

[@Lmanyakaa]

Believe me, the content presented in the lecture is not rigorous at all compared to other stuff in QM. However, HW assignments are most likely from hell.

[@gatormcklusky5850]

I'm sure by now they no longer teach anything but Racisms ,Nothing else matters You don't need that crappy education you need racisms. Your a Victim start acting the part damnit.

[@lukschs1]

Riguroso y convincente xD

[@atlasbailly5439]

however, this content was not rigorous. especially by mit standards. the first lecture is always a softball so a wider audience can watch. either way, I am sure he remains engaging even when the content does become rigorous

[@davidvella7690]

Prof Adams makes a difficult and ambiguous subject easy to understand. I watched several videos on this subject to no avail but this clearly is the way it should be explained. Thanks.

[@dogmandan79]

My 10 yr old son and I just watched this entire thing.

[@tdirgins]

I went to a very well-known university and in 4 years I only had one professor who was as engaging and passionate about his subject as this guy. Kudos to MIT!

[@robertmccully2792]

What does passion have to do with "As far as we know" lecture ?

[@arpityadav.832]

what r u doing now? or thinking to do?

[@chadchad6531]

it's crazy how excited I'm watching a frickin' MIT lecture

[@nishtakasundass6669]

Hahaha your not the only one lol

[@michaeldeng1981]

Why youtube push this to me?

[@bell1095]

Intro takes 9:50

[@sammyandoliver7522]

@@michaeldeng1981 KZbin pushed this to me as well and I'm glad they did.

[@mobetta2092]

Everyone be sure to update your résumés

[@TheSleepSteward]

It's incredible to think that everyone in that room has now graduated and is incredibly accomplished in their own right. That's beautiful. I wonder where they all are...

[@zachansen8293]

so sad you don't do this anymore, you're so good at it. 10:50 the experiments are so unsettling you have to tell the class that you're not lying to them. I love it.

[@donsudduth]

What a great line - "the miracle is not that electrons behave oddly, the miracle is that when you take 10^27 electrons, they behave like cheese!" Awesome!

[@astro_penguin_]

What does "cheese" mean? I sometimes have a tendency to interpret phrases literally-I feel like this is one of those times-yet I can't imagine what the figurative meaning of "cheese" could be.

[@Capt.SumTingWong]

Gotta admit. I’m in bed watching stuff to try to dose off (sleepy but can’t sleep), and I figured this should do the trick. I ended up watching the whole lecture and now feel wide awake. More professors need his enthusiasm. I’ve never seen a classroom applaud following the conclusion of a lecture, but this man earned it.

[@yayadoesstuff3778]

Same exact thing. Tried to bore myself to sleep. Ended up staying up watching the entire thing

[@ashrahman1123]

Same here

[@garethwillmore7105]

Yes, I also ended up in a sleep superposition. Both tired and not tired, asleep and not asleep. I wonder if I watch this one night a week, for six months, If I fall asleep 50% of the time?

[@cybercastor6873]

I personally WAS able to dose off. My wish, is that while sleeping, my brain will understand quantum mechanics in my subconscious, then I will be subconsciously super intelligent.

[@OhAncientOne]

😵‍💫 Fell asleep watching a Tesla 3-6-9 vortex video, woke up just as this ended. After having the WEIRDEST dream in decades, which I have to share: I was in college, & victim of pranksters in a dorm. I lost the pranks war & woke seeing that they had removed the tire from the left rear of my car. Not the rim, it was still there, on the car with the jack laying next to it 😳 🤔 Never fall asleep watching math videos!

[@icy_bird5540]

I love how much passion and energy he has

[@crazyspace6792]

I knew instantly what experiment he was describing in the first part of the lecture and then he said silver atoms and confirmed it for me. The stern-gerlach experiment is one of the cooler ones I’ve ever studied.

[@nid7819]

conlusion : definition of superposition is "I don't know what's going on"

[@JohnDavidDunlap]

Which is a pretty frustrating definition when you're trying to figure out what's going on.

[@mrlarrybobjr]

What I like is how they act so smart but don’t have a clue how this could be.

[@DanAtEXIT]

Had me locked in the entire way. I'm taking away much more than just knowledge, but also how to share ideas in a way people will listen, and enjoy. Give that man a raise!

[@vladv2291]

Knowledge is the only thing you can possibly take away from this. It's all knowledge

[@nameberry220]

@@vladv2291 In this instance knowledge was learned through a joyous and attentive experience thanks to the way it was presented.

[@nolanwhitley1017]

wow... this guy is hands down the best teacher I've ever seen.

[@TheSoundConnoisseur]

I’ve always been fascinated by physics. This is my FIRST video ever in my intent to learn about quantum physics. And I LOVED this

[@ProgrammingRules]

Skip to 10:29 to start the actual physics of the lecture

[@Clickle]

Clouse THANK YOU

[@theearthisaseriesoftubes3768]

The goat

[@site7274]

Clouse thank you

[@Dom-zy1qy]

My goodness. If I had a teacher like this guy in high school maybe I wouldve been so inspired to work hard and go to a great university. He did a phenomenal job, hard to believe this is all live almost.

[@darrellerrad3945]

Teachers like this are unfortunately above most high schools budgets

[@alecmccay7548]

You can get great professors in big state schools and small unique private colleges. I promise there is more teachers like this than positions open there are good teachers to be found

[@tjweav1331]

😮 1:22 😮 1:23 😢 1:23 😮😮😮😮 2:11 😮 3:21 😅😢 3:22

[@tjweav1331]

4:05 😅

[@tjweav1331]

😅

[@benp3485]

This is a Boss Professor, his enthusiasm just makes you want to listen and learn.

[@UnchainedEruption]

Wow this professor is brilliant. I feel privileged to have virtually "sat in" on this course for free.

[@Marguereth]

9:40 is where the actual lecture starts, for those who want to skip through the part where he's going over logistics for the students in the actual class.

[@user-ik7jz6rk4u]

Thank you MIT, I'm 14 and I'm really fascinated about this, although I may not understand some of it, thank you for making these lectures public for all to learn.

[@kenzieusa3356]

2 years later are you still fascinated by this?

[@astro_penguin_]

Thank you MIT!! ❤ Love from Hawaii. Lifelong learners around the world appreciate OCW!

[@johnstebbins6262]

Awesome introduction to a course, especially a course in Quantum Mechanics. I'm sure this lecture will enlighten and motivate those students as they struggle to understand the complex mathematics and details of the course. They'll remember what it's all about.

[@wagsman9999]

Allan Adams is a fantastic lecturer - he has a real gift for teaching. This is BY FAR the clearest presentation of quantum mechanics you will find on the internet. Wonderfully coherent - thanks MIT. (I took a QM course at the University of Illinois ~35 years ago. Unfortunately I did not appreciate the beauty and richness of this subject. Had I - I may have switched majors from Nuclear Engineering to Physics!)

[@Just.A.T-Rex]

I just graduated from nc state for nuclear engineering!

[@elessar7777]

The lecture starts at 9:42

[@ricardoespinoza5821]

thnks

[@thestacker2122]

Ur mind is a stubborn Darn it!

[@mattykotz7219]

This is awesome. Very good presentation. It's like someone showing you how a circle can be created by straight lines.

[@geoffreystuart2172]

Thanks to MIT for uploading these lectures. I understood at the beginning that basically it means that electrons have 2 binary properties

[@martineli15]

MIT, thank you so much for releasing these material on the internet. I'm a brazillian chemistry student and we have a big lack of good material to study around here. We need to spend a giant amount of money for a good book, and theese video classes really help me to improve my knowledge and i'm certain that it helps a bounch of others students that can't get a good material to study so easily.

[@ProgamerEU]

he's so passionate just great! I wish every teacher would be like this

[@takashikashiwase3461]

+ProgamerEU I he is actually bit twitchy ,this is real passion sometime(not always)

[@pwnsl1707]

This presentation style contrasted to my state university experience where almost every chemistry course started with an adversarial rant about us all being a waste of the professor time is incredible to me. I would have paid 4x more to be taught by people who believed i loved learning, but was ignorant. Love of a subject is infectious to even mildly interested listeners.

[@schmetterling4477]

The professors simply told you the truth. Almost all of you were a waste of your professor's time. They hate teaching because they know that in twenty years of teaching they will teach exactly one student who will take over their jobs. That's a fact. If you didn't realize that the first day you sat in a science lecture hall, then you were guaranteed NOT the guy who would replace that professor twenty years down the road. ;-)

[@pwnsl1707]

@@schmetterling4477thank goodness it is only once every 20 years such a presumptuous egomaniac arises! Professor adams must not have received your “peer” memo. Probably because he has actual research backing up his genius

[@jimday6244]

This literally blew my mind. Adams is a great teacher.

[@joelwilliamson3322]

26:50 When he said "This should hurt. This should feel wrong. But it's a property of the real world and our job is gonna be to deal with it." I really felt that.

[@fromanDg]

I’m stuck on this wave of high quality math lectures from high quality learning institutions. I just wish I wasn’t finding them at 11:30pm.

[@conniecendon4740]

Almost 3 am

[@zshorts4849]

I’m here at 6:47am

[@pearidge2936]

You made me realize to check the time -- it's 5:05 AM.

[@jayruane3898]

😂😂😂 exactly same time

[@sammyandoliver7522]

Try finding them at 3AM. Fascinating! I'm glad I did.

[@arindambharali531]

A few professors in India has the same level of enthusiasm and potential to deliver the knowledge to their students. The rest are busy in destroying the potential of millions of students. Education is a money game in India. Respect for MIT and such professors in India who are giving their best efforts.

[@anshulgupta9754]

OMG! I have never seen such a passionate and amazing teacher. I had a constant smile throughout and some good laughs during the lecture. Professor Allan Adams, you rock. Every student deserves a teacher like you. That's how to create curiosity and thrill for the subject among students.

[@iamtackler]

The applause at the end truly shows how amazing of a professor Adams is. Thank you MIT OCW for allowing the rest of the world to experience a professor whose lectures cause students to applaud.

[@SW-mg7et]

Boy oh boy if I had a professor of this class back in my university times here in Finland. Now at the age of 36 I thought that I'm getting stupid and old engineer when I tried to wrap my head around quantum physics, but it seems that reading literature isn't just enough if you don't have great professors like Adams to guide you through the basic concept of something complete new. Thank you for these videos MIT!

[@eliashanba757]

As a uni student of Finland i also can agree with this 100%.

[@smokykirby6290]

@@eliashanba757 Iloilo

[@smolboyi]

God bless Suomi!

[@syedamarmusa6512]

​@@eliashanba757 isn't finland an ideal nation to study abroad

[@3v3pirat37]

39 year old physics major in Quantum now. 100% agree.

[@berkeleycodingacademy7015]

This is my favorite first lecture to any class.

[@bernardoabreu4910]

The enthusiasm of students with the questions is an indicative of the quality and theoretical bases of the conjunct of students present in the class.

[@TomboBrewster]

I do wish my Quantum Mechanics lectures had been like this. Its a blast learning all over again but with the added enthusiasm.

[@jaji666]

Man I wish I had teachers this passionate about physics and teaching like Prof. Adams.

[@guisantanna8330]

I don't know about you, but this lecture was like a movie to me. A movie that takes you along a drama and teaches you a lesson you didn't know before. The end was such a confusing and embarrassing poetry, but beautiful at the same time. That's reality.

[@atlasravenwood6467]

Determinism is reliable on the condition that the quality we rely on is known. This is why it is still a reliable approach to the world as we know it-*as we know it.* It does however invalidate absolute inviolability of determinism under specific conditions.

[@bobthenoob05]

10:25 start of lecture.

[@braeling3677]

I watched this lecture and was like “hey I might understand this” then I watched the second lecture and realized I’m not a physics major.

[@nothankyou5524]

watch this lecture three times spaced three days apart, taking simple notes the second time, and bullet notes the third time. Then, review and move to the next. You'll be amazed if you put some thought into insights you'll get about learning this stuff.

[@jaylintaylor5287]

No Thankyou Too bad university almost never gives you that much time to learn things

[@maazahmedpoke]

trying learning the prerequisites before jumping straight into this unit.

[@gameofpwns1165]

Dude just read Griffiths or something lol. It's super readable.. like Harry Potter but more useful. It's seriously not that hard

[@gameofpwns1165]

@@steamhunter7504 Meant his QM text lol, but his E&M text is choice too. Guess anything new takes a decent amount of time and effort to absorb, fair enough

[@Jeff-gr1on]

I watch these videos sometimes just to see what the professor is like. I'm trying to get my undergrad degree in a less than stellar school where one of the most difficult things is simply dealing with the professors. These videos help me keep working hard to get into grad school elsewhere without feeling like I'm going to be trapped with awful professors for the rest of my life

[@jasonlizotte4007]

Just finished watching this lecture and it has confirmed once again that I made the correct choice going into medicine. Professor Adams is excellent.

[@AM-bj7yo]

I remember watching his lectures during my third year of medicine, honestly it made me consider changing to physics, but then the later lectures came along with all the math and I’ve never been more sure about choosing medicine. But it has to be said what an amazing lecturer he is, and how amazing physics and creation is.

[@davidmartineztorres8731]

@@AM-bj7yo what kind of math do medicine students learn?

[@AM-bj7yo]

@@davidmartineztorres8731 honestly very little, for most doctors we need to be able to calculate drug doses and concentrations, but nothing beyond basic algebra

[@hyzerfl1p]

Do you know simon lizotte?

[@alizain9638]

lol I'm in medicine too. idk what I'm doing here.

[@nicksundby]

When I was an engineering student not once did we applaud a lecturer like that, but we never got such a clear and engaging presentation either.

[@alexgg1950]

Tank you for uploading this classes for all of us students around the world. Professor Adam is full of energy and pasion, is so inspiring.

[@amyamy8873]

I opened this video as sort of a background noise but became completely engaged. Excellent teacher.

[@physicsguy877]

I'm a physics graduate student watching for kicks. He really does an impeccable job of introducing each concept and showing how it is forced by experiment. The lecture actually made me rethink the arguments I was taught in undergrad and sharpen them whereas before I didn't think about them as much. For example, when he introduces the boxes, he does not say that they individually show QM is fundamentally random. A lesser teacher would say, "hey look, each time I send a soft electron through a color box it comes out 50/50 black or white, so that shows QM is fundamentally random", but that'd be a bad argument. A student could just say that half of soft electrons in the world are black and half are white, and you just don't know which ahead of time. It would be impossible for the teacher to adequately answer this student's complaint, because there's no operational way to tell which is right by measuring color. Fundamental randomness in color and randomness due to ignorance both result in a 50/50 split. By introducing the sequence of three boxes at 20:00 he circumvents this argument by instead examining which electrons flip color and which ones don't. If this were not truly random, then we could tell which electrons flip by some additional property, and Bells' inequality shows that no such property exists. Furthermore, this shows that electrons cannot have both definite color and definite hardness, but I just wanted to focus on the randomness aspect because it's often taught poorly in my experience. People don't often present scenarios that force randomness, they merely assert that things are random.

[@lynth]

I don't get it: At 22:41 he says "A measured white electron going through a hardness box, then going through another colour box will have a 50/50 chance to be either black or white." At 50:10 it is then revealed "A measured white electron going through a hardness box, then going through another colour box will have a 100% chance to be white." What is it now? Can you explain this?

[@austinalderete2730]

@@lynth That's sort of the "weird" part of quantum mechancis. It doesn't defy logic, but it defies convential common sense. The simple answer to your question is: both are true, the experiments were different. In one everything was sequential while in the other there were mirrors and paths joiners. Common sense tells you those are basically the same, but in reality they are fundamentally different. The more complex answer is the punchline of this lecture- superposition. The superposition of a particle in an experiment is tied to the probability of obtaining a certain measurement. There are no inherently black or white electrons. You can set up certain superpositions by performing certain experiments. A great example of this is using polarized lenses and light (and you can try this experiment yourself with sunglass lenses). Suppose you have light go through two pairs of sunglasses held at right angles (one is horizontal, the other vertical). How much light goes through? 0. But, take a third pair and put them between the other two diagonally. Suddenly you get some light coming through! It's called the three-polarized light experiment. This defies common sense, but it's an example of how a property can be non-intrinsic. That's what's meant when people say "collapse the superposition/wavefunction". The electron wasn't black or white until you measured it, it just had a chance of being measured as black or white and that chance can be changed. Why the world works like this? No clue. But experiment after experiment shows that it does.

[@lynth]

@@austinalderete2730 Thanks, so the particle is influenced by interacting with the "mirror". What would be the real world equivalent of that experiment... is there an actual experiment like that? Also: That three polarized light experiment... WHAT? How? Haha, do the photons pop in and out of existence? Edit: Ah okay, I just looked it up, the third filter needs to be inserted BETWEEN the other two, I thought you put it after the two which would have been crazy. :D

[@teefkay2]

@Physics guy , perhaps, being a physics grad student, you could help. Just like Lynth, I’ve got a serious misunderstanding. As I understand, there are 5simple rules at work here: 1. Color boxes preserve c9lor. 2. Hardness boxes preserve hardness. 3. Color boxes “scramble (ie., reset to 50/50 probability) hardness. 4. Hardness boxes scramble (same meaning) color. 5. Mirror do nothing except change path direction. In experiment III, he has a white electron interning a hardness box. By Rule 4 above, this should scramble the output to 50% white & 50% black. However, he asserts without explanation that, this time, the color output of a hardness box is NOT scrambled. Can you help explain?@

[@kroijfruihgtrghruib]

Allan Adams is a great professor. As a business student w no interest in physics, i am chocked to find myself passionately watching this video. The way in which he engages students is indeed a talent.

[@AjayKumar-sh8rf]

the hardness and the color box is by far the best way to explain Heisenbergs Uncertainty principle

[@spencerwenzel7381]

One thing that really helps to understand this: Imagine that these electrons can only contain one bit of information. Once a new bit (black, white, hard, soft) has been assigned, on observation, the other information is lost.

[@jeffj5708]

This way of conceptualising is a helpful tool but really it's not the case. When you shoot an electron at a screen, it does have a speed, direction, momentum, energy, spin, charge etc. We just cannot measure more than one quantity at a time. It is a one to one mapping with measurement. One measurement gives one property. Strictly speaking what we are measuring is a probability. Like we ask the electron, what is the probability that you are travelling at 10000m/s, electron says 100% or 5% etc.. You cannot ask simply, tell me your speed but propose one and check probability. It is not really a mystery, every computer works like this, it processes one bit of information at a time but at gigahertz frequency of course similarly we ask one question at a time. The reason why we get probabilities is because measuring is an intrusive process, it requires an action and it changes the electron. Hope this helps.

[@ghevisartor6005]

​@@jeffj5708 im not sure i understood why the mirrors make the electron be 100% if we said earlier that color box-->hardness box--->color box it comes out 50% white 50% black. Why the mirrors cause this and no mirrors doesnt? in the first experiment we measured only one exit of the hardness box and in the mirrors case we use both even with the barriers in between?

[@williamknifeman69]

Thanks to everyone of you guys/ girls who helped make this happen I can just imagine the amount of people that you have helped by making these videos free

[@vinny6935]

Thank you for making this available! It's a fascinating topic, and while I'm an engineer I definitely approach QM from a philosophical perspective. I love the energy that Professor Adams conveys during the lecture.

[@benjohnson1190]

I dropped out of high school, never graduated college, and was able to follow this lecture and understand the explanation. Such an interesting lecturer with a tremendous ability to translate complicated theory into lamens terms. I'm an idiot but I really appreciated his approach to explain something in terms that I could understand. I wish I was as smart as all the people he teaches.

[@msmolyneux3169]

Thank you for posting this lecture. I've thoroughly enjoyed it. The Professor's humor is superpositionly hilarious.

[@richardpoplis6777]

What a professor... i wish i had a professor like this that enjoys his job... great video.. need more

[@melissacairns217]

I love this guy! Teachers like this inspire me to be a life-long learner.

[@rickgrech5577]

Prof Adams passion is what kept the students and audience glued. Prof Adams passion is what kept the students and audience glued.

[@ChadAmI80]

I'm 43. I'm not in the science field and this Prof has me excited about quantum physics. It really does show that a great teacher is key to the success of a class. He is excited, humorous and very knowledgable. If I could only rewind the clock 25 years...These videos are amazing. I really feel like I was sitting in the class. I hope the rest of these are buried in KZbin somewhere for me to watch the entire semester.

[@mitocw]

Playlist: kzbin.info/aero/PLUl4u3cNGP61-9PEhRognw5vryrSEVLPr Course materials: ocw.mit.edu/8-04S13 Best wishes on your studies!

[@swolegrind1947]

This is how teachers should teach. Make education fun. I’m no physics major but this professor makes it interesting to want to learn it.

[@astronau7_lone574]

this guy is the kind of professor every campus needs, a true man of education and enthusiasm kissass or not. thanks man, professor.

[@user-ft1qo7yq6w]

i love this professor so much , he is such a enthusiastic dude

[@shikumas]

Thus prof reminds me of my physics teacher and even tho we are a high school mechanics class, he treats it like an college class and is an amazing teacher. I sit right in front of him and he always makes the effort to engage with his students. Hardest class I have but I don’t regret it one bit.

[@schmetterling4477]

Yeah, but are you learning anything? Probably not. ;-)

[@bonniejocobb6017]

Prof. Allan, stumbled on his video lectures. Looking to test my capacity. His lectures are smooth, easy to understand. Then found open courseware. Prof. Allen's teaching is a diverse style which is needed much. Thank you for dedication to reach many that want to learn.