I always thought Schrödinger's cat was both dead and alive.. until now!

Why is Schrödinger's cat both dead and alive? It's not! In this video we will what quantum superposition is (and what it's not)

Chapters:
00:00 The big misconception about Schrödinger's cat
02:24 A deep perspective on the electron double slit experiment
09:12 An inconceivable tool of the 21st century
10:48 What is quantum superposition (not)?
12:52 Are probability waves real?
14:14 Quantum superposition & measurement
16:42 Electron spin quantum superposition
17:37 The real meaning of Schrödinger's cat!
18:54 How quantum superposition gives you life

This video is sponsored by squarespace

[MannyBrum]

One thing will always be true though, a USB-A connector will always be both upside-down and rightside-up until you look at it. That's why it doesn't go into the port even though you already tried it both ways.

[jaredralls]

My last job I was in quantum superposition;
I was neither working nor fired at the same time

[Fergies]

oh my god, finding out that covalent bonds are just a result of electrons being in superposition just absolutely blew my mind

[gilbes]

Schrödinger's cat is meant to demonstrate the absurdity of some interpretations of quantum mechanics, it is not meant to be a demonstrative analog.
The double slit experiment is a lot of things, and it is usually misinterpreted. It just shows that all measurement requires interaction and interaction affects outcomes.

[philipgmetcalf]

The meowing from the box was probably a give-away.

[TechnooRam]

To be or not to be- Shakespeare.
To be and not to be- Schrodinger

[mahadevparmekar]

Small correction regarding the covalent bond.
Its not the quantum superposition that keeps the two nuclei (of the bonded atoms) together.
Its the 'energy barrier'.

When two elements with valence electrons come together (that is unpaired electrons in outermost shell), the valence electrons have the choice to stay with one nucleus or both nucleus (achieve superposition).

But a stable covalent bond is only formed if the total enery of the electrons in superposition is less than the two electrons that are with individual nuclei.

This energy is lost in the form electromagnetic radiation (typical infrared or visible frequency for most chemical reactions). That's what 'binds' the covalent bond together.

In order to separate them, you need to supply that extra energy from outside. This difference of energy is the 'energy barrier' that makes a covalent bond stable. (Not quantum superposition per se).

If this energy is supplied (like electrolysis of water) the base nuclei will get separated and you get the ingredient elements in pure form again. (Hydrogen and oxygen in case if water).

So its not the superposition that keeps the covalent bond together. It is responsible for forming the bond, but if no net energy is lost, the elements will separate again.
It's the loss of energy during the process that makes a covalent bond stable. (Keeps the nuclei together).

[galen]

The cat has been in that box since 1935. It's dead!

[LogicalNiko]

One of the more interesting things is that we do not really know how complex a system can be before quantum superposition collapses. We’re actually discovering new areas all the time that can only be described by the superposition state. One of the more complex systems we discovered a few years ago is that photosynthesis depends heavily on superposition. If we attempt to model photosynthesis purely in classical particle physics we find that the photon distribution of energy would overwhelm the cells and pretty much result in bonds being broken and the chlorophyll being destroyed. Instead the photon’s energy is actually behaving similarly to the double slit behavior and being optimally distributed across many different channels at the exact same time, leading to less stress on any particular chlorophyll. Thus without this mechanism plants would not exist and we would not have an oxygen rich atmosphere.

[rune_ined]

My 9th grade chemistry teacher actually had a really good analogy for measuring the speed and spin of an electron. She compared it to a spinning fan blade. When it was on, you could determine its speed based on the button or dial, but couldn't get its position since it was constantly moving. When it was off, you could determine its exact position, but could never get the speed since it wasn't moving at all. Good analogy. Of course not exact, but it definitely helped me understand electron spin well.

[meredithgreenslade]

We had a cat and named it Schroedinger. Best cat I ever had. He went missing. I didn't know whether he was dead or alive. He was very laid back sort of guy, so very friendly. I missed him so much. True story.

[vanillabean]

This is the best explanation for quantum superposition and Schrödinger’s cat that I have found, and you explain it in a very engaging way. Thank you

[nikpil]

Your ability to explain things, ask the questions we all have, and then answer them is impressive and makes your content stand out. Keep up the great work!

[duprie]

Schrödinger's cat both dead & alive inside the box is the biggest clickbait ever in quantum physics. Schrödinger intended it to highlight the absurdity of quantum mechanics, that something is missing, then a thousand popular physics authors took it at face value because simultaneously dead/alive cats in superposition sounds super-cool & sells more books lol. Also: nobody ever seems to care that the cat in question constitutes a sentient observer.

[airmanfair]

Every time I see one of your videos I think "oh that's basic stuff, I don't need to watch that", then I think "oh wait that guy always makes great videos" and lo and behold you've taught me something again.

[White-tqsi]

I love the fact that I started out this video clueless about a single thing regarding quantum mechanics except that I know the Schrodinger's cat and now I'm invested in the topic.

[BigWhoopZH]

While I'm sleeping my cat is definitely in a superposition of everywhere on the bed. And sometimes when I wake up just for a brief moment I can see his 9 moonlight shadows on the wall.

[stevekessell]

Probably already mentioned, but it is not true that any interaction collapses the superposition. For example, if an electron/positron 'particle' (i.e. still in the superposition of both) passes near a magnet, the particle interacts with the magnetic field and will bend both up and down. The interaction results in a superposition of paths, where an "electron" would bend up and a "positron" would bend down. But they are still a superposition despite the interaction (a superposition of the particle AND its interactions). If a detector is placed above the magnet, the detector will interfere with whatever turns up (will require some form of entropy change to make the measurement) and it is THEN that the superposition is destroyed. I like the idea that if the decision here is a positron, then the fact the detector 'detects' NO electron, this also collapses the superposition, and a now definite positron continues along on its merry journey, undisturbed, but a fully fledged positron. This experiment has been done many times.
When I was taught quantum superposition long ago, the understanding was that it took a "non reversible" interaction (i.e. where the entropy changes due to the interaction) to collapse the superposition. I still believe this to be true.
Happy to hear other opinions. Cheers.

[ETBrooD]

The act of observing (rather measuring) does not change reality, that's just a very common misunderstanding. Interferrence changes the pattern. When measurement = interferrence, then the pattern must end up being different, because it was interferred with.
This is very important to understand because measurement cannot take place without interferrence. On an electron level it's not possible to measure without interferring.

By the way this is one of the best videos on the matter I've ever seen. You've done a great job!

[joedirty]

This is one of the best videos I’ve ever seen on this topic. Amazing work! Not only teaches superposition well, but also teach HOW to think about complex topics in general.