How Do Scientists Explain Quantum Entanglement?

In this video, four Caltech faculty members explain quantum entanglement, each sharing metaphors and concepts that help describe this mind-bending phenomenon.

Entanglement is at the heart of quantum physics and future quantum technologies. Like other quantum phenomena, entanglement reveals itself at tiny, subatomic scales. When two particles, such as a pair of photons or electrons, become entangled, they can remain connected even when separated by vast distances. In the same way that a ballet or tango emerges from individual dancers, entanglement arises from the connection between particles. It is what scientists call an emergent property.

Featured: Rana Adhikari, professor of physics; Xie Chen, professor of theoretical physics; Manuel Endres, professor of physics and Rosenberg Scholar; and John Preskill, Richard P. Feynman Professor of Theoretical Physics, Allen V. C. Davis and Lenabelle Davis Leadership Chair, and director of the Institute for Quantum Information and Matter.

[ErikBongers]

Wow, how could they not mention the most important aspects of this correlation? That it is instantaneous across any distance. And that the states of the entangled particles are not predetermined at separation.

[brothermine]

Physicists say that a "particle" behaves as a wave while traveling (not interacting with other "particles"). Unlike a point particle, a wave is distributed in space, and it might be helpful to describe the fundamental mystery of quantum mechanics as the question "how can the wave appear to be entirely (its entire quantum of energy) at the point where it interacts when a moment earlier most of it was distributed outside the past lightcone of the point of interaction (seemingly involving a moment of faster-than-light travel)?" This is extremely similar to the entanglement mystery, and it might be helpful to instead think of a pair of entangled "particles" as a single distributed wave (that contains two quanta of energy). That would unify the two mysteries. The reason why I wrote the word "particle" in scare quotes is because the particle model may be just mental baggage that the founders of quantum theory were saddled with due to their classical training, who in turn saddled the succeeding generations of quantum theorists with it too.

[merlepatterson]

My guess is that it's probably not so much "Entanglement (Spooky action) over distance" it's more like "harmonic synchronization over time (irrespective of distance)" due to brief localized interaction. Much like two tops of precisely equivalent size, weight and shape being spun up by the same motor will match their spin rates until they drop from lack of gyroscopic rigidity in plane. Once separated from the motor, the tops are singular entities which share a common initial momentum. A fairly simple test to confirm this possibility would be to conduct an experiment at the ISS with two precisely balance matched gyros, paint a mark on the outer edges of each one, spin them up 180 degrees out-of-phase in a contained microgravity vacuum environment using a single motor, then take high speed images of each one over a period of time. If they remain out of phase, then the correlation may present a good example in explaining quantum entanglement? Or better yet, use precisely balanced "T - Handles" which will precessively 'flip' in synchronicity?

[anslicht]

Only Preskill even made an effort at "explaining quantum entanglement". His book analogy is helpful and I'm sure in no way "wrong", but he didn't give us any hint about how entanglement could exist across distances. Nobody did - they just said it's so cool and maybe we can do X with it. Some of the comments here are better.

[rodschmidt]

I have an idea that entanglement is the inevitable result of a conservation law operating simultaneously with the Uncertainty Principle: spin, for example, is uncertain AND it is also conserved.

[arthurmore]

I see it as a sine wave. The hump and the trough. The hump and the trough are anti particles basically. So they're entangled because they are a part of the same sine wave.

[davidkelly]

I like the idea proposed by some contributors that the 'particles' (or photons etc.) became entangled before the moment of separation, then they maintained the same states, yes like 2 gyros set up at the same spin rate and orientation. Then they will maintain the same state indefinitely as it were. I find this a plausible idea, yet it doesn't explain how any subsequent change of state - let's say induced by a researcher - is immediately duplicated in the twin 'particle'.
The real crux of the discussion is that the commentators in the video explain the basic perceptible behaviour of entangled particles, but don't hint at all about the really tantalizing paradox that the phenomenon very ostensibly defies one of the most important principles of physics which we are all constrained by since the start of our education, which is that nothing goes faster than light. To my way of thinking, unless you address that problem, even by way of reference only, you are not meeting the minimum plausible explanation.

For what its worth, my own line of reasoning goes like this :
First, the rule which says that nothing can travel faster than light is not the full story. Yes, a photon (or any entity, subatomic or otherwise )originating from point A and travelling to point B cannot go faster than light, if it is generated by any standard creation process ; such as an electron jumping from one energy level to another. Any such photon is also constrained to transit from one infinitesimal point in space to another (let's say a quantized 'particle' of space) to the adjacent quanta in a quantized element of time (can't remember the exact theoretical figure), but the result is inevitably that the photon moves at close to the speed of light (depending on the optical density of the medium).
Secondly, if I can make an an analogy to illustrate the difference between a travelling photon (as described above) and a pair of entangled particles ; think of someone swimming slowly in a swimming pool, and then two people are standing at either end of the pool mutually tugging on a piece of string. The swimmer is constrained to move at a very finite speed but the two people beside the pool can interact instantly at each of the pool with minimum delay. In the case of entangled particles, they are utilizing a fundamental property of space that means they use whatever quantum field or otherwise which connects them instantaneously and is not subject to the speed constraining mechanism which I alluded to above.
For myself personally, I only feel satisfied by invoking a model such as I have described . It is good to explain the manner in which entanglement manifests itself, and especially pursue the exciting possibilities of emergent technologies, but without a coherent explanation of why it happens, the physicist feels unfulfilled.
I would welcome further discussion, elucidation or correction . Thanks

[Shioning]

Why would two particles need to communicate to react the same way to the same stimulus? They'd just need to be coded the same. "Same" is perhaps not the best term as the coding might be to react in a manner that mirrors, is opposite of, or divergent from the other. Where the stimulus is observation and the only way to know what they are doing at any given point in time is to observe them in the same manner then their reaction in a certain manner doesn't require communucation but rather just be their coded response to the particular stimulus. Anyway, obviously not my field but fun to think about nonetheless so thank you for that.

[sjfrank]

Cant get my head around it, despite the distance a change in one affects the other instantly? I understand enough to know things on the quantum level don't adhere to the same laws. But even so, its still information traveling faster than the speed of light. Or its not traveling and they exist in both places at same time. I don't know, my head hurts.

[russchadwell]

Particles that became separated after achieving the SAME WAVE FUNCTION.

there.

[ashbyedwards]

I’m clearly an idiot, but isn’t the fuzziness prior to observation the real mystery here? How the particulars repeat in observation seem as coded and predictable as DNA. It’s the interconnected fuzziness that I can’t get my head around.

[zohaibhabib]

I am happily emotional about Quantum Physics because Quantum Physics is happily emotional about me 😂
This is called Emotional Entanglement
Have you ever experienced when your friends laugh without much reason you would laugh too … it is how things work
With good comes good and with bad comes bad
It is all Subtle because it ultimately has to Endure and because it is Enduring it must be Subtle
We have started to describe existences by their virtues
Understanding by Collective Observation
In one word it is Belief and even the Universe is believing in itself out of something

[mikkel]

QE is a smart feature by the Universe to make, Delayed Choice Extended.

[PATDevine-ed]

Some people know what im thinking, very precisely, without any time limit.... Quantum Intanglment?

[carloschambliss]

I would NEED their EXPERTISE to pull OFF the NEXT WORLD wonder!!!!

[Birdylockso]

Apparently, the dumbing down here is hardly enough. To me, it's still as clear as mud.

[kristyandcowreact]

😂😂😂Anyone else here bc they watched Apply TV's Dark Matter 😂😂😂

[palmettokid]

You guys and gals suck at trying to geek/speak the phrase “I don’t have a clue”. Read Nachmonides or Ramban’s 13th century thesis. You’ll have to find which paper. But, He describes it and explains it. You’ll have to drill down a bit to sort out his verbiage of molecules, particles, and general quanta lingo; but, it’s there. EPR and the derivation of Bell's Inequality is not as in-equal as it is thought.