Quantum Superposition, Explained Without Woo Woo

A common phrase in quantum mechanics is: "The electron is in multiple states at the same time." But it's actually a lie. Quantum particles like electrons are never in multiple states at the same time. It's just that most quantum states don’t make sense to us.

00:00 Cold Open
00:28 Quantum Spin
01:02 Ball Analogy
02:46 Vector Spaces
04:59 Quantum States
06:58 Quantum Measurement
09:24 Bra-Ket Notation
10:31 Summary
11:23 Outro
11:46 Sponsor Segment
12:52 Featured Comment
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VIDEO ANNOTATIONS/CARDS

Lagrangian Mechanics:

Quantum Wave Functions:

Quantum Spin:
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Commercial Meme:

[derigin]

Up until now, I've never seen someone explain quantum mechanics in a way that actually left me thinking "that makes sense." Thanks for making me feel a bit smarter than I was before.

[Gustavobc]

nick i cannot overstate how much i love this and your channel in general. the way you manage to take unintuitive concepts that are generally regarded as "impossible to grasp if you're not in the field" and actually explain them without oversimplifying to the point of inaccuracy the way they're often presented shows the incredible pedagogical talent you have developed, and i'm unimaginably thankful for having found your channel

[EvilSandwich]

Looking at that Vector graph with the rough and smooth axis suddenly made it click in my head and hit me like a ton of bricks why it's so completely useful to use complex numbers to represent Quantum States. Holy crap it makes so much sense now! Thank you!

[Uhlbelk]

You are an amazing science communicator. Thank you for your hard work.

[logarhythmic]

8 years after graduating and going into a career that has nothing to do with physics, I thought my PHYS 486 knowledge was lost forever. But this video, even though it's fairly high level, brought back SO much; much more than I thought it would. I'm with Nerd Clone wanting a video on eigenvectors now.

[powluiz]

I just can't imagine a more intuitive way to understand this. As for the quality of the video animations... there are no words to describe how well done all this is. Thank you very much!

[vulpesaxis]

I always accepted this concepts of quantim superposition without giving it much of a thought, since I'm not a physisit it really didn't matter that much to me, but as a mathematician I love this concept, it is waaaay easier to understand and makes absolute sense to me. So thank you Nick

[Joel]

It has always driven me nuts when someone says "particles can be in multiple states at the same time" because it makes it sound like quantum mechanics is mystical or magic when it's not. It's really unfortunate because it also plays into the myth that quantum mechanics cannot be understood on some level. This explanation was excellent.

[odiesback]

Outstanding explanation! There are a lot of smart scientists out there but very few can break it down to a layman’s level like this. You’re doing more for science than you can imagine!

[MukMn]

I always thought quantum mechanics was something I could never understand, but I think you've completely changed my mindset with one video. I'm not saying I truly understand it, but this is the first time anything about quantum mechanics has made some amount of sense to me. Great video

[koraptd]

"we're going to be traveling light" if not that scene with laughter i wouldnt even realize the wordplay

[jeffwilliamson]

"Oh no, here it comes" said my brain as I clicked this link. Nick, you're going to be so disappointed in me (or maybe not). At this point in time, I am a quantum mechanics skeptic, because of the application of Occam's Razor. "Particles can phase in and out of existence spontaneously!", "information can travel faster than the speed of light!", "consciousness is somehow intrinsically linked to physics and collapsing the wave function of a double slit experiment actually supports quantum theory!"
... Those sound like fantastical claims to me, and you taught me better than that. Absurd claims in physics need to be held to absurd amounts of rigor, the likes of which we do not yet have the technology to hold quantum mechanics to.

[ComradePhoenix]

My man's really pondering the orb right now.

Also, that "smooth vs rough" vector space seems to imply the properties of negative smoothness and negative roughness.

[ItsEverythingElse]

The bra vector isn't important until we start taking measurements :)

[amingholizad]

This makes more sense than any other superposition videos I have watched in 10 years

[rahulbosebose]

6:57 Bra vector isnt important until we start taking measurements.
Is that a joke? 😂😂

[oldieman]

Thank you. I struggled with the perception of things existing in Superposition. Just because we can think of it like that, doesn't mean things have to be until we observe them.

[KeithCooper-Albuquerque]

Thanks Nick! This really cleared up the superposition myth that has permeated all of physics. I'm a former computer programmer (but not much math), but I'm learning so much from your channel. On the question of German, I had three months of German in 10th grade, then we moved to a school that didn't have German as a course. I'm going to use Babble to continue my learning. Thanks for this wonderful double whammy of excellence!

[lorenzobarbano]

Finally someone said it!! It's not a superposition of states. It's only 1 quantum state. It's a superposition of classical states, or of observable states...

[weiniesail]

Amazing that you could explain this so well. Even my old physics profs and books for the lay person use analogy to explain superposition. Now, take that leap and apply this easy to understand logic to quantum entanglement/bell's theorem!