All Questions
19 questions
23
votes
6
answers
6k
views
How do we know that entanglement allows measurement to instantly change the other particle's state? [duplicate]
I have never found experimental evidence that measuring one entangled particle causes the state of the other entangled particle to change, rather than just being revealed.
Using the spin up spin down ...
- 247
22
votes
6
answers
5k
views
Quantum entanglement and spooky action at a distance
When quantum entanglement is explained in "layman's terms", it seems (to me) that the first premise, that we have to accept on faith, is that a particle doesn't have a certain property (the particle ...
- 323
14
votes
3
answers
3k
views
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 ...
- 12.9k
12
votes
2
answers
2k
views
EPR-type experiments and faster-than-light communication using interference effects as signaling mechanism
I understand that faster-than-light communication is impossible when making single measurements, because the outcome of each measurement is random. However, shouldn't measurement on one side collapse ...
- 7,488
4
votes
0
answers
249
views
Are all instances of quantum non-locality problem artifacts of the use of classical concepts in quantum physics?
Consider experiments involving entangled spins, say two-spin 1/2 particles in the singlet state:
$$\left|\psi\right> =\frac{1}{\sqrt{2}}\left[\left|\uparrow\downarrow\right> - \left|\downarrow\...
- 10.3k
3
votes
1
answer
3k
views
How does the notion of weak measurement resolve Hardy's paradox?
How the notion of weak measurement resolves Hardy's paradox?
- 1,260
3
votes
5
answers
2k
views
Is quantum entanglement an objective or subjective property?
Imagine the following gedankenexperiment. Observer Alice is right here on Earth. Observer Bob is at say Alpha Centauri. A pair of maximally entangled qubits is formed with one qubit handed over to ...
19
votes
1
answer
7k
views
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 ...
- 1,841
15
votes
8
answers
2k
views
Given entanglement, why is it permissible to consider the quantum state of subsystems?
Quantum entanglement is the norm, is it not? All that exists in reality is the wave function of the whole universe, true? So how come we can blithely talk about the quantum state of subsystems if ...
- 151
15
votes
3
answers
2k
views
Couder-Fort Oil Bath Experiments and Quantum Entanglement Phenomena
The oil bath experiments of Couder and Fort have been able to reproduce various "pilot wave like" quantum behavior on a macroscopic scale. Particularly striking is the fact that the double-slit ...
- 1,171
11
votes
3
answers
8k
views
What are non-local hidden variables?
It is said that Bell's Inequality basically denies all possible local hidden variables theories as solutions to entanglement but what does a non-local hidden variable theory mean and how does it get ...
- 312
8
votes
2
answers
1k
views
How is the non-local nature of quantum entanglement explained?
From what I understand, Einstein tried to introduce real but hidden variables to remove the apparent non-local nature of quantum entanglement, but Bell's inequality showed local realism isn't possible....
- 1,108
8
votes
2
answers
406
views
In quantum mechanics, can we measure anything else than position?
In the basic quantum mechanics lectures, we learn that we can measure any observable. That means mathematically, all Hermitian operators correspond to a physically measurable quantity. In strong ...
- 3,270
8
votes
0
answers
267
views
Free Will Theorem question
The Kochen-Specker Theorem says, if I understand it correctly, that the results of spin measurements cannot be predetermined independent of measurement. They get to this conclusion by describing 33 ...
- 81
4
votes
3
answers
458
views
Many Worlds locality and EPR experiment
I've read in Sean Carroll's book (Something Deeply Hidden) that the Many-Worlds interpretation of quantum mechanics might be the only way to avoid instantaneous effects of entanglement, by having the ...
- 41
2
votes
1
answer
356
views
How does the Many-Worlds Interpretation of Quantum Physics relate to Consciousness? [closed]
According to the Many-Worlds Interpretation of Quantum Mechanics, each quantum event causes the world to "branch" into a superposition of outcomes.
How come "my" consciousness only chooses one of ...
- 75
2
votes
4
answers
209
views
Does Bell’s theorem rule out changing hidden variables?
In the EPR experiment, it is said that there are predictions that are made if there are hidden variables determined by something locally in each particle that results in a correlation in entanglement. ...
- 21
1
vote
2
answers
316
views
How does the many-worlds interpretation look like in bra ket notation?
If I understand correctly the many worlds interpretation says the universe is continously splitting into multiple branches and quantum measurements occur when decoherence causes a quantum state to ...
0
votes
2
answers
343
views
What stands behind the quantum nonlocality appearing in entanglements, and why Bell's inequalities are violated?
I noticed the question whether Bell's inequalities are based on a false premise,
(https://physics.stackexchange.com/questions/219904/could-bells-theorem-be-based-on-a-false-premise) but I bring ...
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