Can You Make a Quantum Computer out of Olive Oil?
Vložit
- čas přidán 28. 06. 2024
- Thank you to Brilliant for sponsoring this video! To try out interactive STEM courses for free, visit brilliant.org/PhysicsfortheBi.... The first 200 subscribers will get 20% off of an annual premium subscription.
Why on earth did Wikipedia say that olive oil performs spontaneous parametric down-conversion? In this video, we learn the basics of quantum mechanics and we use it to explain why extra virgin olive oil shines red with a green laser. We also learn how scientists were able to use a protein found in jellyfish (and GloFish!) to create entangled particles.
0:00 Introduction
2:12 Quantum Mechanics
6:10 Olive Oil and Chlorophyll
10:07 Green Fluorescent Protein
13:13 Message from Sponsor
QM Reference: Intro to Quantum Mechanics, Griffiths
Olive Oil Science: www.aromadictionary.com/EVOO_b...}
More Olive Oil Science: pubs.aip.org/aapt/pte/article...
Entanglement in Green Fluorescent Protein: www.nature.com/articles/s4146...
I think it is important to clarify that it is not "observing" a quantum system that makes it resolve itself into a specific outcome, but rather the object interacting with something other than itself that forces it to resolve its state. The object is not conscious and it happens independently of human observation. It's important to consider the language we use so as to not give the quantum systems, nor ourselves supernatural qualities.
Interaction is observation
- Chris Fields
@@pluto9000 In the context, yes. But most people don't have that background. It's important to make that distinction clear. To "observe" something you have to interact with it. You must change it by affecting it.
This distinction disappears the moment one realizes that "conscious matter" is not any different than "ordinary matter". Existence observes itself with or without the awareness of the observation/interaction/interdependence
@@0FAS1 But that isn't common knowledge and not making that clear can build an inaccurate understanding of concepts in science.
@@0FAS1 the problem is, not everyone is a materialist and quantum "observation" had been repeatedly misunderstood and used to "prove" the soul.
i honestly think this channel is underrated. really excited to see you grow as u deserve
like honestly your explanations are very clear and to the point and they are comprehensive, i really appreciate :) its not usual to be able to tackle subjects as difficult as the ones you explain as easily as this channel allows to. thanks :)
@@ppmico Thanks! I'm always worried that I complicate things too much and I'm also always worried that I simplify things too much, so I'm glad you're getting something from it!
@@physicsforthebirds I really like your niche/small channel style, when channels go big they usually go towards a more mainstream style which feels like a TV show rather than a genuine random idea fuelled by fun and curiosity.
I also like things coming completely out of left field sprinkled with sarcasm and existential crisis. So I really like you overall.
@@physicsforthebirds i assure you, i'm pretty dumb, and i find these videos both insightful and feeding a level of curiosity that makes my brain real happy
@@physicsforthebirds I think you do a fantastic job of neither over or under explaining
Using quantum mechanics to understand Olive Oil was not on my Life Bingo Card
I wonder when the scientists are going to realize that they can just entangle particles with just some string and a pair of tiny baby hands without having to resort to jellyfish and olive garden
i love you physics for the birds...
Agreed
Uh... I love you too
@@physicsforthebirds XD im sorry last night i was having a hard time because i couldn't solve even the easiest question. Opened up CZcams very depressed and there it was on the top, a new video from my favorite channel :D
I appreciate you saying "no" right away. You earned that like in that exact moment. Great content
You videos have such a unique style among other educational content. They are so cozy and warm, and hands-on without reliance on spectacle. I hope you will become even more popular, you really deserve it.
The particle knows where it is at all times. It knows this because it knows where it isn't, by subtracting where it is, from where it isn't, or where it isn't, from where it is, whichever is greater, it obtains a difference, or deviation. /s
Haha, I saw your comment right after posting mine, also with that reference
This difference is called Error
It therefore follows that the particle has no knowledge about it's momentum. It doesn't know its momentum because it doesn't know what its momentum isn't. There is no sensible way to subtract the momentum it has from the momentum it hasn't, nor the momentum it hasn't from the momentum it has, nor is it possible to define a rigorous notion of whichever is greater...
There may be more than one force at work in the particle of light. One electric, which only has a velocity, and the other magnetic, which is only stable in one place! The light is moving unless it has a reason to stall, such as a relationship outside of itself- the measurement is one. Fun!
Rockwell Automation has shills for that Turbo Encabulator everywhere.
3:25 The electron does not know where it is. It doesn't know this, because it doesn't know where it isn't, so it can't get the deviation by subtracting where it is from where it isn't (or where it isn't from where it is, whichever is greater).
A fully accurate quantum mechanics parody of that would honestly be peak
Hey bird, your videos really strike me. You spark interest in what I otherwise wouldn't consider. I've been involved in the sciences my entire life, and just now, I started university. I struggle a great deal with discovering where I want to go with my studies. I'm currently in bio and chem but physics gets me incredibly excited and I understand it quite well (in a theory aspect). However, I struggle largely with math. I can barely get by calculus on my own and I know physics is all about waves, functions, inverses, etc etc. I just really want to know your opinion when having to delve into physics without proper mathematical skills. I would love to make a career exploring the latest breakthroughs in physics but I'm scared I will struggle and make a wrong choice. Sorry this was such a long comment but I would love to hear what you have to say. Thanks again bird
Have you heard of 3Blue1Brown and Khan Academy? 3Blue1Brown makes really good animated videos on a whole load of maths topics, including calculus and linear algebra that are really good for building intuition. Khan Academy also makes videos, and they are organised into courses like traditional schooling. They helped a lot in high school and uni.
I'm glad my videos are interesting enough to make you consider physics! That's exactly why I make them!
Everybody's experience is different, but I always thought I was good at math until I started university. I was taking math classes with very smart people and I felt like I wasn't able to keep up. I took linear algebra 3 times in some form or another, first from the math department, then from electrical engineering, then from physics, and what I found was that I really didn't understand most topics until I did them concretely in physics. But once I did physical examples, I was able to go back and understand the math on more abstract levels. If you think you aren't good at math, you should try it in different contexts before you beat yourself up and decide that you'll never learn math.
With all that said, you at least need to _enjoy_ math if you want to study physics, even if it takes some searching to figure out when you enjoy it!
Found out your channel about a week ago, through the popcorn video and was surprised about how well your videos are made, truly an awesome work. If you keep like that, in no time you’ll get lot of subs and view, rlly appreciate the efforts you put on the animations, talking and even the sources on the description. Hope we see you thrive soon, good work!
I’m so glad I found this channel, thank you so much for creating such unique and inspiring content; I love the way you often explore topics at a scientifically deeper level than many channels, but still keep everything accessible and clear :) I’m looking forward to all of your future content and growth!
Wow, the intro was so efficient at presenting entanglement
So clear
love your stuff. finishing my BSc in physics and these jus kinda scratch my brain the right way. idk why the mood you set while talking about familiar topics just kinda soothes me. thanks
Always excited for a new video from this channel :).
Taking a quantum computing course this quarter but it's more focused on the theoretical foundations for qubits and gates. Love to hear these musings on more practical problems when it comes to the physics of obtaining an entangled state :) (and it certainly doesn't hurt that they're accompanied by such cute drawings)
This was a great video and I really love your story-telling and animations! :)
This video was the first time I've almost understood entanglement and wave function collapse. I'm not quite there because I don't get what actually counts as an observation, plus how do quantum computers work when the particles they're made of don't even know what they are? How can you trust any results to be accurate? Someday I think I'll understand but you helped me take a step in the right direction I think
I want to know how to make entangled particles. I want to know how they know it is instantly transmitted to the other particle. Also want to know more but for now I am happy with just understanding these two ideas.
🙋
There's nothing special about "observation", it's just that any interaction between a particle and the world forces the wave function to collapse so that a "decision" can be made about how the world should behave in response.
Fundamentally, all forms of observation involve outside interaction, because in order to gather information about the state of a particle, that information has to be communicated from the particle to the outside world, and thus the wave function is always collapsed by observation.
Like he says in the video, an observation is any interaction with the outside world. Observation is a purely conscious concept, which is why some scientists don’t like to use it, but it does work when you consider for us as humans to understand anything, we need to interact with it in one way or another.
I’m not an expert on quantum computers, but to my knowledge a qubit is in a superposition of 1 and 0, and using very complicated techniques you can influence the output you receive through the input, and the output should give you certain pieces of information about the input. There are other channels that understand it and can explain it better than me.
@@pluto9000 think of it like a coin toss, but this coin is special in that if viewed in a mirror, the heads & tails are switched. if you toss the coin, while in the air, neither the coin, nor anyone else in the world knows what the coin's "polarisation" (heads or tails) is. But as soon as it falls, or you catch it (making an observation), you will immediately know that the coin in the mirror world would be the opposite of your reading, or vice versa.
@PeachCrusher69 That is an interesting way of explaining it, I still don't quite grasp the concept of a particle not having a defined state on creation, but that helps me understand it a bit better, once the particle interacts with another one it's state has to be defined otherwise their interaction would just not happen, and the entagled particle has to be reversed in order to maintain the energy equal to the original superposed state.
Can't get enough of these videos, I'm learning so much. Thank you!
Cute cartoon of a dilution refrigerator at 11:34!
N.B. 3:49 is accurate but a little imprecise. It’s possible to have linearly or circularly polarized light in a superposition of horizontally and vertically polarized states too (per choice of HV basis). Linear polarization and circular polarization are special cases of elliptical polarization that can correspond to the 50/50 HV probabilities you show at 4:07.
N.B. 3:58 and 4:08 are inaccurate, and you need to be careful regarding what parts of this quantum “system” you’re talking about. If you’re talking about the quantum state of the smaller system “photon after polarizer,” the photon already “decided” its polarization (and pass/no-pass) when it encountered the polarizer and was projected onto the vertical state, before it encounters your eyeball. Your eye is not required to modify the photon’s state in this perspective, nor is your eyeball projecting passing photons onto the vertical state. If you’re thinking about the quantum state of a larger system of “photons before and after polarizer,” the polarizer is actually part of the system too. After a photon encounters the polarizer but before encountering your eye, the whole system (photon and polarizer together) is described by a mixed state of “vertical polarized, passing photon” and “messy whatever happens when the photon is absorbed by the polarizer and decoherence kicks in.” If you’re skeptical, consider this: the inner product of the state of any quantum system with itself MUST be 1 (i.e. the system has 100% probability of being in some quantum state). The state corresponding to “50% vertical probability and nothing else” isn’t possible without using mixed states.
This video has amazing explanations of the included bits of quantum mechanics
New vid from this channel feels like christmas, thanks for the vids & keep up the quality!
I'm really loving the music you use
Great to see you already got sponsored by brilliant, good stuff! Love the calm vibe of the videos.
Amazing video! I am having a related course in uni and I am amazed by the amount of research you put in your videos 😳
Great work again, this is becoming my favorite science youtube channel
Really good explanation and graphics. Thanks!!
I wish these effects applies to large scale objects too, that would make the daily life more interesting
I am so incredibly lucky to have found this channel.
I am a linguist, but have always been interested in physics etc. And you are so amazing at explaining it thoroughly and simply at the same time, while also being able to keep my neurodivergent attention for long enough to finish the video.
This video may genuinely be the source of the most quantum physics I've ever learned, even though it is a topic I was always interested it. Just didn't seem to really get it before.
Welp, sorry for the long comment, guess what I'm saying is:
Thank you so much, Birb!
I love this channel, always waiting for a new upload.
Hell yeah, bro got a Brilliant sponsorship.
Cool stuff, bro. Thanks
The way you explain the material and relate it to physical phenomena is effective and truelly delightfull!
Keep it up!
If you see this, may i ask what your background is?
this channel is gold, I'm glad to see you upload these amazing videos every time >:) I hope you will grow to become the next big physics channel you deserve it!
Every video is a treat
Good job with this one, i liked it a lot
omg i love ichthyology and quantum mechanics this video is perfect
I love your closing music
The first time I’m seeing these concepts demonstrated so intuitively
Finally, a good definition of entanglement. Congrats on you and Chris Ferrie's book for explaining it well.
Cool video
A little warning about the laser: 30 mW is enough to fry your retina. Use a class II instead and / or some laser goggles that block green (you should still be able to see the red). Also be aware that many cheaper 'safe' class II green lasers omit the IR filter and may be putting out quite a few additional mW of IR that you can't see.
I think the biggest issue with understanding quantum mechanics is the use of the term "observe" or "measure" people assume concious observer but any interaction counts as an "observation" or "measurement" even if its two carbon atoms interacting a billion light years away
This is the video ive been needing, not the one i deserve but the one i needed
Another wonderful video!
Keep up the great work man!
Saw an upload, I click.
Very cool video! I had a lot of fun watching this and learning about Quantum Mechanics 🐠🐦🐱
I am physics teacher in high school and i often show your videos to my students, you are doing great :)
Keep it up!
Excellent video, this channel is awesome
your videos are great, my eyes will appreciate a dark theme.
Very cool jellyfish. Thank you, jellyfish.
oh my goodness! i had just identified a picture on inaturalist the other day of that jellyfish which apparently only lives here in the pnw. and now i learn it's where that glow protein comes from in this video!
that's so cool, and weird, it's not like i'm regularly thinking about jellyfish, that was the only one recently. i'm finding the world works in mysterious ways.
quantum mechanics in general is also kind of scary and weird and cool, thanks for explaining some! i knew particles could be entangled but didn't know specific ways it actually could happen.
Good stuff!
amazing video
It’s time like this that I’m glad to have read the Rascal does not Dream series for its tackling of quantum mechanics
Love this channel
8:05 I swear ive been to this exact sprouts...
Do you have a patreon or somewhere to support you? This has quickly become some of my favorite content on CZcams.
I got my bachelor's in physics and work in a related field. Yet this has been the most stimulating engagement I've had with these big concepts since college. It scratches an itch I had missed so bad. I've not found other CZcams channels that meet that need, so please know how appreciated this is!
It makes me happy that you're enjoying the videos! I'm actually working on putting together some treats for patrons before launching a patreon, but it should be up very soon!
This channel is amazing, the way you explained quantum mechanics was great. I am doing a school project( I am in 8th grade) about quantum internet. and the information you explained helped my project so much. Your explanation on SPDC is great! Because of you I learned so many new things! My project is 10 times better because of your video! Thank you for your amazing videos!
Awesome! Let me know how the project goes!
@@physicsforthebirds Yes I will, I will present it on may 9th (my birthday)! I REALLY want to send you the link to it (it is a google site) but I also don't want the entire comments to get the link to my website. If I knew being a bird meant getting these types of videos about physics before, I would have became a bird earlier!
Also I have put you in the citations and in the special thanks!
@@GirusBetterThanVirusHow did it go? :D
@@aileenyxit went great
You have a gift to teach disparate physical and natural phenomena in such an intuitive way.
Do you not understand how soul crushing this video is???
My soul, my everything was dedicated to creating a quantum computer that uses olive oil. Every day I toil in the mines creating olive oil and growing the silicone to create the supercomputer. What will do now?
Hey I love your videos!! Would it be possible for you to make videos on not such a white background. I usually watch videos at night or in dark rooms and the white background really pops out. Cheers ❤
I think of it more like when the entangled photons are emitted, they each have opposite polarizations, and are both already in whichever state that they are in when one gets measured (and then let's you know the other is opposite). They 'know' exactly which state they should be in ever since they were emitted. we just have no way to determine which state they're in until measuring them. so they're in a superposition only as far as our knowledge of them is concerned. in actuality they've always been in the 'collapsed' waveform state the entire time. there is no need for instantaneous information transfer upon viewing one to determine the other
like, imagine two sisters were going to an event and wanted to wear different color dresses... you know that they coordinated before leaving that one would be wearing red, the other blue. what you don't know is exactly which sister is wearing red and which will be wearing blue, you just know that those are the options. (the sisters are in a superposition of either wearing red or blue). when you arrive at the event, you say hi to one of the sisters, noticing that she is wearing red (the superposition waveform has collapsed) so you can intuit that the other must be wearing blue, and sure enough you see her later and see that she did wear blue. this doesn't mean that the sisters were each "maybe wearing red, maybe wearing blue" No, they decided before going out who would wear which color, they just didn't tell you about it. so to your perspective, you had no clue until you finally saw one of them later. sister 1 was always going to be wearing the red, and sister 2 always the blue. you just had no way of knowing until you saw for yourself.
if information was transmitted upon 'measuring', then that would mean that when you saw the first sister in red at the event, she turns around and calls the second sister to tell her to change into her blue dress right then and there. that wouldn't make any sense.
Look up bell's theorem. You are postulating a hidden variable theory, which is impossible if you also want the theory to be local.
i’ve been to that sprouts
1st can we DO this at home
2nd will this same non-liner bbo do both Up and down Conversation like if we sine higher wavelength from other side wil it also Combine to higher frequencies?!
The worlds first quantum computer video to feature the materials used to create entangled pairs
I dont really understand any of this but you describe it so simply i feel like i almost can.
I like thouse Videos and i always Watch them. Today i was learning quantum mechanics in german for my Uni and had some Problems. To procastinate i started to Watch some CZcams. And this Video is the second I Watch. Well now i understand them a Bit More.
For the polarized glasses example, wouldnt it make more sense to say that the photon that was blocked does "know" when its measured by the glasses but the one that isnt doesnt until it reaches your eyeball ?
This man just explained quantum computers to me in less time than it takes to take a shit and I respect that
Probably shit faster without the phone
This is a really interesting concept! But, your audio seems very quiet. I'm not sure if it's just me but it would be something to look into.
I love your videos :)
This video is the perfect example of molecular bioengineering. I am going to use it now when people ask me what it is.
Galium arsenide phosphide can be adjusted to have diode potwntials from near ir to green. Which is why blue led got a nobel. Is it possible to use 4 wave mixing on blue/uv of the sun, so that solar panels can be made from just ga asx p1-x ? Or that spontaious parametric thingy. So long as blue and uv can become green yellow red or near ir. Because SiC based blue is not efficient for photon absorption or emission
The level of this channel is insane.
Great video! Also, we live nearby each other haha! Kind of neat, I wish I knew more people that were into physics nearby. Oh well, glad to know there are others haha.
Idk if it was your explanation being extremely well done and simplified, or if it's just bad, but I think I've come to the realization that Quantum Mechanics is a stupid semantics game.
Entanglement sounds like you broke a cookie in half and tossed them in the air, and then said "You don't know which side is the up or down until they land! And they're going to fit together mysteriously!"
Yeah, of course they're going to be opposites of each other, you just broke them in half. They fit together. Why is this a surprise?
It's all semantics and sophistry.
I have a question for anyone that is able to understand this. Before explaining spontaneous four-wave mixing (11:11) he showed how a particle might move between energy levels. But in the diagram he used heat to move from S2 to S1 but needed fluorescence to move from S1 to S0. Why is fluorescence need to return to ground state but not needed to move between other energy levels. Sorry this is long i just didnt know how to explain it shorter.
Nice video
the goat posted
10:12 "or does it?"
Vsauce music
Well, technically,,,,, the probability (±density) function is actually the absolute value of the wavefunction squared :)
Great video, watched it until the end.
The only thing I must point out is that the music was sometimes way too loud and distracting. Maybe tune it down in the future.
Noted! I'll edit with a variety of audio setups next time.
@@physicsforthebirds Just to provide another opinion: personally I thought the balancing was solid (music fading in and out appropriately for intro/outro segments)
Yayyyyy new video 🎉
great video! do you know the name of the music in the background during the intro?
All of the music I use is mine, made for the videos. I might release it all on its own at some point!
@@physicsforthebirds its great stuff! your video on jazz and entropy has been super informative for my composition work, the overlap between music and physics is super interesting :)
What if I drink the genetically modified quantum olive oil
Another banger
I love this channel
keep making these absolute bangers bird man
What's the name of the song you use in your intros?
Upvoted for not leading us on until the end of the vid.
something i still dont understand about quantum physics is why the particles are described as choosing their state when theyre interacted with instead of when they get entangled. Why would it be like that, how would you even be able to prove that they werent already in that state if you can only tell what state theyre in after you measure them
The information that determines which state the system assumes upon observation(the term for interaction), is not encoded upon observation(interaction), but is encoded at the moment of entanglement.
:D
The information doesnt actually have to travel between the particles, it was already encoded in the past.
This misunderstanding is very common... and it makes it seem like "magic"... but there is nothing magical happening xD
So i must point it put to everyone >:3 (I'm looking at you, New Age Hippies!!!)
exactly, this video is so wrong in so many ways
Nice
does this mean that true randomness exists within the wave function eg.
o = particle w/0 spin
P = particle w/+x spin
N= particle w/-x spin
o? = particle w/unknown spin
o ---> P + N
%50 chance after one observation that o? is P
Some fungi fluoresce green and orange in the presence of ultraviolet light, could this be quantum entanglement?
Great Chanel! But Music way too loud!
00:41 wait, there are 2 options and you check one. isn't this just process of elimination? 3:07 so a wave function is a list of possible parts in a particle and their rarity? 3:48 what if each particle had multiple predetermined parts before it was "observed" and the glasses are just straining it? 6:04 "collapsing the wave function" seems to be an accounting of expected parts. am i tripping or does this boil down to which cup is the ball under? if someone could enlighten me i would appreciate it.
you're right. this video made an awful job trying to explain quantum physics.
each entangled photon gets the state immediately and when we measure one it just shows the state it doesn't magically transfer information to the other photon, the information was there all along
@@Oscar4u69 thanks. but if that's how it works doesn't it makes Schrodinger's cat really dumb?
@@NuclearLama Schrodinger's cat was Schrodinger showing how "stupid" and counterintuitive the idea was.
@@NuclearLama I wouldn't say the video is awful. And saying that each entangled photon immediately gets its state is misleading and might even be wrong. The truth is physicists don't know if the state is determined after or before measurement. It's still an unsolved problem called the measurement problem (physicists don't even know what counts as a measurement!).
But most physicists believe that the state of the particle is only determined at measurement*. This is what is taught the most and what the video assumes and what I'll assume for the rest of your questions:
00:41: Yeah there are only 2 options. But we don't know which particle is up or down until we measure. Before we measure one of the particles, no one knows. Not god, not the particle, not the universe, not anyone. It's not that the case that the particle determined its state after being split and that it's just unknown. It determines only after measuring.
So you're correct that after measurement, it's pretty simple and we can just use elimination. But what makes QM interesting is that the particle doesn't decide its state until measurement.
3:07: Yeah basically correct. Although if you want to be more technically correct, the parts of the wave function squared gives you the probability.
6:04: Collapsing the wavefunction picks one of the possible parts. But the interesting thing is that the particle doesn't pick the part until a measurement is made.
I wouldn't say its like picking a ball under a cup. In this analogy, the ball is already under one of the cups. The measurement doesn't change that fact. Even though we might not know which cup its under, the ball still is under just one and only one cup, even before measurement. Even if you don't know where the ball is, God, the ball, the universe, [insert your choice of omniscent personification here] knows which cup the ball is under.
That's not what the quantum particle does. The particle isn't in one cup before measurement. The particle doesn't know what cup it's under. God doesn't know what cup it's under. The universe doesn't know what cup it's under. Only when you measure it, does the particle/God/universe/you know.
* So you might be asking why most physicists think that the particle doesn't choose its state until measurement. Why don't physicists think that the particle gets its state immediately but its just unknown until measurement (called a hidden variable). The answer is that we don't know which of these two contrasting viewpoints is correct for certain. But there's a theorem called Bell's Inequality which says that if the particle gets its state immediately, then Quantum Mechanics is completely wrong.
Physicists have rigorously tested lots of predictions from quantum mechanics and have not found anything contradicting the theory, so most physicists and so that seems to imply that hidden variables don't exist. If hidden variables don't exist, then that means the particle only gets its state after measurement.
Now you might ask what is a measurement. This again is an unsolved problem and this comment is already too long, so just Google the measurement problem.
Hope that helped!
"Interaction" is a miles-better term than "observation" -- it's both accurate and intuitive.
Why do macro objects not exhibit quantum behaviour? Easy intuitive answer: nothing known could possibly stop every single one of zillions of particles (a Mole of water is only 18mL, btw) from interacting.
One issue Ive always had with quantum physics is if we have to entangled photons people use language like "if we observe the spin of one the spin of another is forced to change." How do we know its being forced to change? How do we know it wasnt always in that spin position before observing and really by observing it we're taking a coin flip and saying it landed on heads after the reveal?
NO ONE ever explains that its just taken for a fact of 'the quirks of quantum science'
Yes there is literature dealing with that specific stuff.
You have to read:-
Bell's inequality
EPR paradox.
1. Q: The entangled particles decides its spin right after it gets split, not at measurement!!! It's just that the spin is unknown.
Short Answer: The above statement is MISLEADING at best and might even be WRONG.
2. Q: What is a measurement, really? Isn't it just when an interaction occurs with an external particle or force? Does it have anything to do with consciousness.
Short Answer: Physicists don't know what a measurement really is. And no, an interaction is not the same thing as a measurement. A measurement probably doesn't need a concious being.
3. Q: Isn't this just an overly complicated version of when we have a ball hidden underneath 2 cups and we don't know which cup it's under until we "measure" by lifting one of the cups?
Short Answer: No.
4. Does it really matter whether the particle gets its spin right after entanglement or if it gets its spin only after measuring? Isn't this just bad philosophy by physicists to make things seem more complex or a matter of annoying semantics?
Short answer: Yes! It matters. They are fundamentally different things! It's not just physicists trying to seem smart or being pedantic.
LONG ANSWER:
Physicists don't fully understands what a wave collapse is or what a measurement is!
That being said, there are a few good and not so good perspectives and ways to interpret QM (Quantum Mechanics):
1. Realist (aka Local Hidden Variable Theory): The quantum system is just like a ball underneath some cups. The ball already has a determined cup its under. We just don't know it until we measure it. There must be a hidden state or a hidden variable that somehow describes what state the ball is in since the realists think the ball is already under a determined cup. QM must be incomplete since this hidden variable isn't anywhere in modern QM.
2. Orthodox (aka Copenhagen Interpretation): The quantum system is not like a ball under a cup. We don't know what spin the particle is in until we measure it. No one in the universe knows what cup the ball is under until we measure. God doesn't know what cup the ball is under. The ball doesn't know what cup its under. [Insert omniscient personification here] doesn't know what cup the ball is under until there is a measurement. We say the measurement causes the particle's wave function to collapse. The act of measuring "creates" the spin of the particle or forces the ball to be under one of the cups, but not before.
3. Agnostic: Bury your head in the sand and don't think about it cause it doesn't matter when the particle gets its spin, since after all either way we don't know until we measure. The difference between the realist and orthodox perspective is just semantics.
4. Other: More advanced or modern ways to explain measurements and wave function collapse. Examples might include non-local hidden variable or everett (many worlds) interpretations.
Let me start by saying that any serious physicist will only consider the "Orthodox" or one of the "Other" interpretations. This video considers the Orthodox position, since this is the oldest (so it's stood the test of time and hasn't been proven wrong by experiments), it's what most students are taught, and it's also more conceptually simple compared to the "Other" interpretations.
The Realist and Agnostic interpretations are unlikely to be true because of a something called Bell's Inequality.
Bell's Inequality is a mathematical statement that is implied by realism. Physicists showed that if realism is true then that means Bell's Inequality is true. But the surprising result is that if Bell's Inequality is true, then quantum mechanics is not just incomplete, but completely wrong.
Many experiments have been performed and have shown that quantum mechanics is extremely accurate and have shown that bell's inequality is false, which basically means that realism is very unlikely to be true (in fact the most recent 2022 Nobel Prize was awarded to physicists who showed that Bell Inequality was violated or false).
Since realism is probably wrong, then that means that there actually is a difference between orthodox and realism. So there really is a difference between the particle having a definite spin before measurement versus the particle having the definite spin only after measurement. Thus the agnostic position is wrong. There are real physical differences that can be found through experiments. So you can't bury your head in the sand like an agnostic believer.
What is a measurement, really? Isn't it just when an interaction occurs with an external particle or force?
A measurement is not just an external interaction. A particle that interacts with an external particle doesn't necessarily have to result in a measurement. In fact, Quantum computers work by manipulating particles in superposition using external fields/particles, but this doesn't result in any collapse in the wavefunction (so it's not a measurement). The particles in the quantum computer still retain a state which is a superposition. So not all external interactions are measurements.
So you might ask what kind of interactions are measurements (i.e. causes the wave function to collapse). Again this is an unsolved problem in physics (google the measurement problem). But again there are a few good and some bad interpretations of what a measurement is:
1. A measurement is made when a macroscopic (classical) system interacts with a quantum particle/system or what a scientist does in a lab using classical tools like a ruler, stopwatch, spectrometer, etc. (Bohr)
This is probably the simplest way to imagine what a measurement is and works pretty well for intro level QM. This is what the video defines a measurement as.
2. A measurement is when an irreversible process occurs, aka increase in entropy.
3. A measurement is made when a conscious being observes something (Wigner)
4. A measurement is made when a permanent record is made (Heisenberg)
I think 1 and 2 are probably the best ways to think about what a measurement is. Most physicists don't think 3 is right since all known physical laws don't really care whether humans exist. All these perspectives have problems of course. Like for 1, what differentiates a macroscopic and quantum system? When does the transition occur. And for 4, what does "permanent" mean?
* Footnote: Bell's Inequality only holds if particles affect each other slower than the speed of light. Some newer theories with hidden variables can work if the particles can influence each other at faster than light speeds (called non-local hidden variable theory).
D.J. Griffiths and D.F. Schroeter, Introduction to Quantum Mechanics, 3rd ed. (Cambridge University Press, Cambridge, 2018).
^ for those with more math background, check out the proof of bell's inequality.
Making quantum computers out of microbes? Damn, that’s some Rain-World-esque tech right there
pls reply with ending track name
All of the music I use is mine, I made it for my videos. I've been promising people I'll release it someday!
4:08 how do we know the photon doesn't know its polarity?