All Questions
Tagged with quantum-entanglement wavefunction-collapse
43
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Is it possible that a macroscopic object tends to a separable state without the need for objective collapse?
For a multi-particle system, superposition is in some sense equivalent to entanglement; with the Dirac field being treated as classical under second quantization, for example, we could at least argue ...
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Was Einstein "spooky action at a distance" about entanglement or about wave function collapse?
I've been watching Sabine's videos and this is my understanding:
There is no "spooky action at a distance" based simply on entanglement. Entanglement is a correlation. There is no ...
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4
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331
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Is signal photon independent of idler photon in Delayed Choice Quantum Eraser?
--Diagram from Wikipedia of the experiment of Kim et al. (1999)
Original research paper: A Delayed Choice Quantum Eraser
I want to know whether the landing position of the signal photon (photon that ...
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Simultaneous measurements of two entangled particles [duplicate]
Experimental evidence reject the local hidden variable theory, so let's say quantum mechanics is right and the wave function does instantaneously collapse upon measurement.
Suppose we have two ...
19
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Is my interpretation of the underlying idea behind this 2022 Nobel Prize story “How physicists proved the universe isn’t real” more or less accurate?
I’m not very good at math but I frequently watch PBS Spacetime on YouTube to try to satisfy my curiosity about physics despite that.
In a recent video by Dr Ben Miles titled “How Physicists Proved the ...
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Postulate of wave function collapse and entanglement
Can we say that a measurement on a system of $k$ entangled particles is the cause of the collapse of the wave function into $k$th states simultaneously?
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1
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Quantum entanglement
Suppose we have two particles with entangled eigenfunctions. Let's say they are in two different regions of space, with different local Hamiltonians. Now we measure one of them, therefore the other. ...
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Quantum entanglement information through time of collapse
(I've tried my best to find an existing question that asks this question exactly)
From what I understand, given two entangled particles, one held by Alice and one by Bob, when a measurement is done by ...
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Have objective collapse theories been ruled out by recent experiments?
Have objective collapse theories been ruled out by recent experiments, such as the entanglement of macroscopic objects? (vibrating drumheads)
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Will the Hilbert space get expanded when measuring the entangled state?
If I have two electrons that are indistinguishable, as I understand, they are entangled. And the Hilbert space that describes the behavior of this pair of electrons is a subspace of the Tensor product ...
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Has there been experimental evidence that entangled state collapses simultaneously?
If we observe the observable of one particle among two particles which are entangled each other and separated far away, we can determine the value of the other particle’s same observable from the ...
user296657
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Detecting collapse using single slit
A collapsed state should act like a particle and a non-collapsed like a wave. Is this statement true? So if you had a single slit and detectors behind it off to the sides... The collapsed state should ...
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Does an entangled pair remain entangled after the first measurement?
Consider an entangled pair described by the wavefunction
$$\lvert1,0\rangle = \frac{1}{\sqrt{2}}(\lvert\uparrow_1\downarrow_2\rangle-\lvert\downarrow_1\uparrow_2\rangle)$$ in in the $S_z$-basis. If ...
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Are combined fermion wavefunctions still antisymmetric after wavefunction collapse?
If we have two electrons in a state $|\psi\rangle=\frac{1}{\sqrt2}[|\uparrow\downarrow\rangle+|\downarrow\uparrow\rangle]$ and we measure the spin of the first electron to be up, does the wavefunction ...
- 2,604
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Identifying Collapse in Wave-function [duplicate]
Is there a machine or instrument which will notify us instantly when the wave-function has collapsed if we have access to only one of the entangled particles? Note that the wave function collapse will ...
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3
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Is there a way to detect the collapse in wave function of entangled particles instantaneously? [closed]
Is there a machine or instrument which will notify us instantly when the wave-function has collapsed if we have access to only one of the entangled particles? Note that the wave function collapse will ...
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Problem regarding quantum entanglement and special relativity
So this question is about the strange phenomenon of quantum entanglement, or "spooky action at a distance", as Einstein called it. In particular, it's about the simplest conceivable case of ...
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Wave function collapse for experimental quantum state preparation
Has the John von Neumann projection, or the wave function collapse, been used in the experimental preparation of quantum states? As an illustration, for a pair of EPR-type entangled 2-level atoms
$$|\...
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Is there anyway to know when the wave function collapse?
If we get 2 entangled particles and move them away from each other, is there a way to put one of them is some kind of "sensor" that would tell if the entangled particle have been measured?
If yes, how ...
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Can we tell if a particle has collapsed due to a measurement?
Suppose we have two electrons A and B.
My friend measure the spin on electron B the value is +1/2, and he writes on a piece of a paper the value.
Electron A has not been measured, so the spin is in ...
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If I have a two-electron problem, and I measure the position of one electron. What happens to the quantum description of the other?
Suppose I have a two-electron system, and they are left alone for a long time, such that I do not know where each of them is. I then measure one electron at position $\vec r_1$. Does this collapse the ...
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Does Quantum Entanglement have a preferred reference frame?
What I mean by this is, with wave function collapse,--and by extension, collapse between two entangled particles--being nonlocal (instantaneous across space), in what reference frame does the ...
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When does quantum entanglement cease?
On Wikipedia on Quantum entanglement:
“However, this behavior gives rise to seemingly paradoxical effects:
any measurement of a property of a particle performs an irreversible collapse on that ...
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Instantaneous quantum features
Two of the most striking quantum oddities are entanglement and the wave-function collapse or state vector reduction.
Firstly, quantum entanglement is the quantum phenomena involving states of ...
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Doesn't the Schrödinger's cat inside the box cause the probability wave function to collapse long before a human opens the box?
My point is that there is no superposition of dead and alive. The cat will cause the probability function to collapse long before we open the box. What am I missing here? Isn't the cat capable of ...
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Does Quantum Entanglement happen between two wavefunctions? [closed]
Does the entanglement happen between two particles or two wavefunctions? If it's wavefunction then what happens to the two wavefuntions after getting entangled?
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Annihilation Operator on Entangled State - How Does This Not Break No-Communication Theorem?
If I have the state
$$|\psi\rangle=\frac{1}{\sqrt{2}}\left(|2\rangle_{A}|0\rangle_{B}+|0\rangle_{A}|2\rangle_{B}\right)$$
and apply the annihilation operator to B
$$a_{B}|\psi\rangle=|\phi\rangle=\...
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Does entangled states must become non entangled states after the measurement?
In tensor notation. A state vector $|uv\rangle$ is a tensor product(non entangled states) if and only if there is $A\in E_1(u)$ and $B\in E_2(v)$ such that $A\otimes B$.
So by postulate of quantum ...
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Wave function collapse, EPR paradox and information transfer
For a classical formulation of the EPR paradox, two particles are produced, with total momentum zero and separated by a long distance. So say we measure the momentum of one particle first, and measure ...
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When light reflects off a mirror, does the wave function collapse?
This question is specific to the Copenhagen interpretation, which states that the wave function collapses on interaction. If we have a beam of light reflected off a mirror, whether you see this light ...
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What processes cause the collapse of a wavefunction and break entanglement?
This question states that measuring the spin of an entangled particle causes the collapse of the wavefunction and thus the entanglement is broken.
Then this question states that we don't know what ...
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Decoherence/wave function collapse between entangled photon pair
If photon 1 and 2 are position entangled and they go in different directions, would making a measurement on photon 1 effect photon 2? If photon 1 is detected can photon 2 still create interference?
user86072
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457
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Wave function collapse of entangled photons?
If we have two entangled photons then they are described by the same wave function. But if I measured the position of the signal photon and it collapses into a position, would the idler photons ...
user86072
5
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1
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Mathematical formulation of partial wave function collapse
If given a wave function which is an element of a Hilbert space $\mathcal{H}$ which is a tensor product of two other Hilbert spaces $\mathcal{H}_1\otimes\mathcal{H}_2$, how do you formulate ...
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Causality in space-like separated collapse of entangled pairs
Suppose two spacelike-separated measurement events take place on an entangled pair of particles, both of which events, in isolation, would cause the entanglement to collapse.
It is impossible to say ...
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Is wavefunction collapse “global”?
I have the feeling that the premises of this question may not be coherent (so to speak), but here goes:
Suppose we have a system $X$ in a quantum superposition between states $0$ and $1$, say, with ...
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Precedence and quantum entanglement: The Alain Aspect experiment in spacetime
Recall that the spin components of a spin-entangled pair do not exist until one of the pair undergoes quantum observation, at which time both of the pair immediately obtain quantum random opposing ...
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If Alice is moving at relatavistic speeds compared to Bob, is collapse still simultaneous?
I have read some papers about experimental proof of non-locality involving a laser that goes through a beam-splitter and then each "half" goes to an observer (traditionally "Alice" and "Bob"). It has ...
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Entropy before and after collapse of the wavefunction and interpretation?
Seems like it might be pretty rudimentary but I want to see if my thinking is on the right track as well as what the result means.
The question is, is the entropy of the collapse of a wavefunction or ...
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How is it possible that quantum phenomenons (e.g. superposition) are possible when all quantum particles are being constantly observed?
I don't understand how quantum mechanics (and therefore also quantum computers) can work given that while we work with quantum states, particles that this quantum state consist of cannot be observed, ...
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What happens to entangled particles when momentum is measured?
In Wikipedia it is mentioned that position and momentum can be entangled as well as spin and polarization etc. I assume etc. is charge etc.
I understand how if you measure spin up on one of a pair you ...
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Quantum Entanglement - Measuring Twice
In the answer here and on the wiki article and many other articles it is mentioned that if one of 2 entangled particles is measured their state collapses according to the Copenhagen interpretation.
...
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Entanglement and the double slit experiment
Is the double slit experiment an example of entanglement when it seems as if the photon is going through both slits? Or put another way, is it at this stage when we attempt measurement we see a photon ...
