All Questions
32 questions
28
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1
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The choice of measurement basis on one half of an entangled state affects the other half. Can this be used to communicate faster than light?
It is often stated, particularly in popular physics articles and videos about quantum entanglement, that if one measures a particle A that is entangled with some other particle B, then this ...
- 135k
27
votes
5
answers
7k
views
How does QFT help with entanglement?
I'm a bit confused. QFT is claimed to incorporate both Quantum Mechanics and Special Relativity. Therefore it should address the problem of non-locality caused by entanglement. However when I search ...
- 539
15
votes
5
answers
14k
views
Does entanglement not immediately contradict the theory of special relativity? [duplicate]
Does entanglement not immediately contradict the theory of special relativity? Why are people still so convinced nothing can travel faster than light when we are perfectly aware of something that does?...
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12
votes
2
answers
3k
views
Entanglement and simultaneity
According to the special theory of relativity, distant simultaneity depends on the observer's reference frame.
And, according to the quantum theory, in the case of two entangled particles, a measure ...
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5
votes
2
answers
409
views
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 ...
- 51
4
votes
1
answer
717
views
Is quantum entanglement affected by time dilation?
Is quantum entanglement affected by time dilation?
Let's say one of the entangled pair is accelerated to very high speed. When both the entangled particles are observed at the same time, will they ...
- 143
4
votes
2
answers
333
views
Why is quantum non-locality so surprising when quantum mechanics is a non-relativistic theory to begin with?
Ignore the fact that Quantum Field Theory (QFT) is compatible with Special Relativity (SR) for a second. Imagine we are back in a time before the construction of QFT. If Quantum Mechanics (QM) is the ...
4
votes
6
answers
683
views
Local EPR-experiments with photons in vacuum?
The principle of non-locality states "that an object is influenced directly only by its immediate surroundings." (Wikipedia)
When two entangled particles are measured in an EPR experiment, we ...
- 3,151
3
votes
3
answers
1k
views
Faster than light signals and the price to be paid if we accept them: a very simple protocol
Some physicists currently understand entanglement as transferring information instantaneously, yet not violating causality. Is this really a satisfactory explanation, or should be look for something ...
- 6,920
3
votes
1
answer
258
views
Does the no signalling theorem in quantum mechanics beg the question?
I had always thought similarly and then came across a paper here that argues this.
The abstract is as follows:
Many authors state that quantum nonlocality could not involve any controllable ...
2
votes
2
answers
266
views
Bell inequality violations evidence for 1935 EPR claims?
Is it possible that Bell inequality tests provide experimental evidence in support for the EPR claims in their 1935 paper titled "Can Quantum-Mechanical Description of Physical Reality Be Considered ...
- 69
2
votes
2
answers
673
views
Is space-time a Kantian concept - just a concept of the working mind? [closed]
Is space time a Kantian concept – that is, just a concept of the mind at work? That is that there is no ‘out there’ – it’s in the ‘mind’?
Relativity might work but it certainly requires a stretch of ...
- 29
2
votes
0
answers
97
views
Teleportation and boosted observer, special relativity
According to relativistic quantum information, entanglement, purity of states are not Lorentz invariant.
Here I check such a problem. If we have two coordinate systems $R_A,R_B$ with relative ...
- 1,576
1
vote
2
answers
1k
views
Energy transfer using quantum entanglement
Can we transfer energy from one place to another separated by arbitrarily large distances without any time lag?
For instance, if Alice and Bob are two observers making measurements having a singlet ...
- 11
1
vote
5
answers
181
views
Entanglement collapse and relative order of events
According to QM (and many confirming experiments) outcomes (e.g. spin) of entangled particles measurement are non-locally correlated (i.e. can’t be pre-configured for such correlations).
It seems that ...
- 93
1
vote
1
answer
764
views
Why does entanglement not imply hidden variables?
By the causal symmetry of spacelike-seperated events, the statement "measurement of particle 1 causes subsequent collapse for particle 2" is equivalent to "measurement of particle 2 causes subsequent ...
- 111
1
vote
0
answers
85
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Question about Relativistic effects on Quantum entanglement [duplicate]
Let us consider the case where there are two entangled electrons, one with A and the other with B; whose spin Z can be measured. Let the state of the system be $$\frac{1}{\sqrt{2}}\left ( |00\rangle + ...
user279008
0
votes
3
answers
146
views
Entangled particles and the Andromeda paradox experiment
I know there are other questions linking the two subjects. I am not asking about an explanation, rather I am curious whether an experiment would be possible.
To explain the experiment let's start with ...
- 1,036
0
votes
3
answers
395
views
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 ...
- 39
0
votes
3
answers
493
views
Why does a violation of locality not imply a violation of relativity?
This question is closely related to: What counts as information?
Taking the specific example, again, of the EPR experiment. I think everyone agrees on the following:
The act of measuring the ...
0
votes
2
answers
164
views
Successive measurment of incompatible variables on an entangled state
Suppose I have 2 particles in an entangled state with opposite spins far away from each other, both stationary with respect to the lab. At time t=0 I measure the spin of both particles in the x ...
- 1,066
0
votes
2
answers
150
views
Quantum entanglement from different frames of reference and the conservation laws
From my understand, if the wave function of a particle in entanglement collapses by being observed, the other particle's wave function also collapse immediately.
My questions are:
Is it possible to ...
- 105
0
votes
1
answer
455
views
Relativity and Entanglement
Say we have two particles which are entangled so that they have opposite spins. If one is up, the other is down. They are sent off to two spatially separated observers A and B. Both observers can ...
- 1,114
0
votes
4
answers
138
views
Is the interference pattern of an entangled particle affected by the measurement of it's pair far enough away to take into account special relativity?
I've been considering a theoretical setup for a quantum experiment where 2 particles are prepared with entangled spin. They are then moved far away from one another where particle B is next to Bob who ...
0
votes
1
answer
526
views
How is instantaneous action at a distance governed by a specific frame of reference?
Instantaneous action at a distance may occur due to an experiment being performed within a train. A particle may decay in the middle of the train, and when decaying it may split into 2 entangled ...
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0
votes
1
answer
80
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Entanglement and Special Relativity [closed]
There are 2 particles entangled and move far apart to 2 measuring devices . The first measurement of either particle will collapse the wave function and set spin up and spin down on the particles. 2 ...
- 11
0
votes
1
answer
67
views
Quantum entanglement of a particle [duplicate]
I recently got to know that two particles are entangled and they share information instantly no matter how far they are kept from each other. It is also said that if one particle is kept at one side ...
- 172
0
votes
0
answers
114
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Does quantum entanglement imply a universal "now"? [duplicate]
If a particle on earth is entangled with a partner particle in Andromeda, and the wave function collapses here on earth, the wave function would, as I understand it, collapse in Andromeda too. Does ...
- 127
-1
votes
2
answers
138
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Does the recent announcement of information transmission via entanglement really indicate superluminal information transfer? [duplicate]
Given that various answers here at Physics assert that information isn't transferred (such as this Phys.SE post), and given recent announcements, does this invalidate our understanding of what's ...
- 151
-1
votes
2
answers
184
views
Quantum entanglement and relativity
I'm having trouble understanding the interplay between special relativity (more specifically the relativity of simultaneity) and quantum entanglement.
Imagine there are two observers, as shown in the ...
-2
votes
6
answers
486
views
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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-3
votes
2
answers
288
views
Quantum entanglement and special relativity PARADOX [closed]
Imagine two entangled atomic clocks. After we entangle them, we measure the time: it does has to be the same , right ?
Now lets suppose that we entangle them , but don't measure them, then we plant ...
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