Quantum Entanglement Explained - How does it really work?
1,097,363
Published 2021-07-30
Chapters:
0:00 - Weirdness of quantum mechanics
1:51 - Intuitive understanding of entanglement
4:46 - How do we know that superposition is real?
5:40 - The EPR Paradox
6:50 - Spooky action and hidden variables
7:51 - Bell's Inequality
9:07 - How are objects entangled?
10:03 - Is spooky action at a distance true?
10:40 - What is quantum entanglement really?
11:31 - How do two particles become one?
13:03 - What is non locality?
14:05 - Can we use entanglement for communication?
15:08 - Advantages of quantum entanglement
15:49 - How to learn quantum computing
Summary:
Albert Einstein described Entanglement as “spooky action at a distance,” where doing something to one of a But it's not spooky action at a distance, at all. So what is entanglement?
Electrons have a quantum property called spin that makes them act like little magnets. We’ll always measure it pointing in one direction or the opposite: up or down, say. If we entangle two electrons so that their spins are always pointing in opposite directions, the two spins are said to be correlated. If we entangle the two electrons in this way – and fire them in opposite directions, we don’t know which one of the pair is up and which one is down until we make a measurement. If we find that electron 1 is spin up. We know the spin of electron 2 must be down.
Why isn't this like a pair of gloves? The handedness of the gloves is there from the start. It never changes. With entangled particles that’s not the case. They are in a superposition. Prior to measurement, there is no definite answer.
How do we know superposition is real? The double slit experiment is good evidence. Entangled particles are stranger, because a measurement on one particle determines the outcome for both of them.
Albert Einstein thought up an experiment like this in 1935, in collaboration with two younger scientists, Boris Podolsky and Nathan Rosen. They are referred to as EPR for short. They believed superposition was impossible because information cannot travel instantaneously. So they thought there must be hidden variables. But Danish physicist Niels Bohr, said that Einstein was just wrong.
Scientists remained divided. in 1964, Irish physicist John Bell figured out how to set up an experiment, Bell's inequality, to determine who was right. Bell proved that quantum mechanics predicted stronger statistical correlations in the outcomes of some measurements than any hidden variable theory could.
When Bell’s experiment was first done in a lab in the 1970’s by physicists John Clauser and Stuart Freedman at the University of California Berkeley, it showed that there was no sign of hidden variables.
How are two particles entangled? You can entangle two photons from birth or you can bring two quantum objects very close together.
Once objects are entangled, they’re not separate. They are, really two parts of a single object. In quantum mechanics, objects are described by wave functions: mathematical expressions that encapsulate all that can be said about the object. This wave function can be spread out in space. This is why particles can act as if they are waves. But if we entangle two particles, they are then described by a single wave function. They are mathematically the same object.
Entanglement tells us is that the quantum world has nonlocality: things at one place don’t depend just on what happens in the neighborhood of that place, as they do in the classical world. Quantum non locality is an alternative to spooky action at a distance.
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It will not let us communicate faster than light because only knowing how they are correlated can provide any meaningful information. This has to be transmitted at the speed of light.
The advantage to using entangled particles to send messages is you can encrypt the message in a way that it can never be intercepted and decrypted without that decryption being detected. Entanglement is also the key to quantum computing.
All Comments (21)
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I don't experience quantum entanglement now that I've moved to wireless headphones.
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That explanation is even scarier than spooky action at a distance when you think about it
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I have been searching for hours for a video that would explain this concept clearly. I finally found it. Thanks so much. This deserves a like and a sub.
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After 4 years I finally discover the one video on the internet that actually explains quantum entanglement clearly. Thank you Arvin for your hard work. Once you realise they are not two separate particles - that there is only one wavefunction - everything falls into place.
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I really appreciate these intermediate level videos. You help close gaps in our understanding of these complex theories. I've known about entanglement for years now, but watching this video really helped me to grasp it in a mind blowing way. You are the real MVP Arvin!
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Just wanted to say I recently found your channel and I'm already addicted. The ideas are expressed/described very well while still getting into things that are difficult to say in a conversational way.
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Awesome explanation. I have read a lot about entanglement but still had some challenges to really understand it. Your explanation makes it all clear now to me, especially the part where you explain that two entangled objects are being described by the same wave function. Thank you so much for this.
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Fantastic video! I finally get entanglement, because you stated very succinctly the assumption EPR (and the rest of us) have been making that the two particles are not separate but the same wave function. Lots of other videos don't mention this basic problematic assumption or glide over it very quickly so that it isn't clear. Thanks!
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I can see your head again! I hope whatever that was is gone now and you are healthy and wittier than ever! Great vid as always (y)
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What a GREAT video!! Never before has it been mentioned that these particles "met". This made so much sense to me! Im a lay person who loves quatum physics. Great Job! Definitely subscribing!
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Amazing video. Ive watched a lot of videos that explained the recent findings in a well manner but none of them explained how quantum objects are entangled in the first place. Great video 👍
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Wonderful work Arvin...taking us to the application in electronics, quantum computing. Amidst the wash I gathert it's technology that has improved our theoretical knowledge...observing an actual electron...in a manner of speaking ... is a case in point. The ability to do this was previously thought impossible. I look forward to following your work.
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This is the only YouTube channel l have watched that actually made me consider buying a full course on third party websites
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Sounds like everything is submerged into some larger field, keeping a perfect balance of energetic potentials.
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I love learning new ways to think about entanglement. This description was marvelous! thank you!
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Exceptionally well done Arvin. This is the most intuitive explanation I have seen yet.
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How grateful should I be to Arvin Ash for providing wealth of knowledge ! Heartfelt thanks 🙏🏼
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Arvin, halfway through you went through entanglement pretty fast, but then you caught back on where you left off on the later part of the video. This made my understanding of quantum particles much clearer. thanks of that. good video
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Thank you, cool video! Also it feels so good being able to understand what you're talking about coming fresh from a physics course in modern physics.
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You make the most mind blowing things so easy to understand. Thank you ✌🏻
