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remormalise
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If you change the spin of an entangled particle without knowing its original spin, what happens to the other entangled particle?
An entangled pair share one wave function. So they are in a way one thing. If either one is projected into a different spin state the partner will have the same/opposite spin ( the '/' depends on the preparation).remormalise said:If you change the spin of an entangled particle without knowing its original spin, what happens to the other entangled particle?
remormalise said:can you impart up spin on all particles, would this break the entanglement
Nothing. You will change the total wave function of the two particles, but you can't say that something has happen to the first particle.remormalise said:If you change the spin of an entangled particle without knowing its original spin, what happens to the other entangled particle?
I don't understand here. If by "all particles" you mean the two you have, then putting them both with spin-up doesn't corresponds to an entangled state.remormalise said:Assume you don't need to know its original state, can you impart up spin on all particles, would this break the entanglement or down spin all the entangled particles
You cannot learn quantum mechanics from videos on the internet. They're fun, they're interesting, some are better than others, but there is always something missing.Abiologist1 said:I've recently seen the excellent youtube video on "Quantum Entanglement & Spooky Action at a Distance" by Veritasium - but either I'm not understanding something - or there seems to be something missing from the explanation.
The local operator can choose to measure the polarization on any axis they want; whatever result they get, a measurement of the other photon will produce the opposite result. Say the operator holds their polarizer at an angle of ##\theta## degrees. If their photon passes through the filter, they have just measured the photon to be polarized at that angle; if it doesn't pass they've just measured it to be polarized at 90 degrees to that angle. Either way, if we measure the other photon with a polarizer at the same angle, we will find the opposite polarization result.It seems that the operator can choose the ANGLE of polarisation of both entangled photons (+_180 degrees) - even if one photon is very far away - is this correct ??
Nugatory said:However, that doesn't mean that the operator has any control over the angle of the remote photon. No matter what anyone does and no matter which angles are chosen for the two measurements, the remote observer will always find that half the photons clear his filter and half are absorbed.
The percentage that clears the local operator’s filter is always 50%, no matter what the angle of the filter, just as with the remote filter.Abiologist1 said:regardless of the percentage which clear the filter of the local operator ? - or do you mean only in the case that half the photons clear the local operator filter and half are absorbed ?
Nugatory said:(And I should add that there are serious practical difficulties in actually performing this experiment in exactly this form - this is a thought experiment as described)
Entangled particle spin is a phenomenon in quantum mechanics where two or more particles are connected in such a way that the state of one particle is dependent on the state of the other, regardless of the distance between them. This means that if the spin of one particle is measured, the spin of the other particle will be the opposite, even if they are separated by great distances.
The exact mechanism of entangled particle spin is still not fully understood, but it is believed to involve a combination of quantum superposition and quantum entanglement. Essentially, the particles are in a state of superposition, meaning they exist in multiple states simultaneously, until one of the particles is measured, at which point the other particle's state is determined.
Entangled particle spin has significant implications for quantum computing and communication. It allows for the creation of qubits, which are the basic units of quantum information, and can potentially lead to faster and more secure methods of computing and communication.
No, entangled particle spin is a phenomenon that occurs on a very small scale and is only observable in controlled laboratory settings. It is not something that can be observed in everyday life.
One of the main challenges in studying entangled particle spin is the difficulty in creating and maintaining entanglement between particles. This requires precise and delicate equipment, as well as a controlled environment to prevent any external factors from disrupting the entanglement. Additionally, the interpretation of the results of experiments involving entangled particle spin can be complex and require a deep understanding of quantum mechanics.