All Questions
32 questions
0
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3
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110
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Is it possible to affect spin probability of an entangled particle?
Say I have entangled particles A and B. Assuming we are talking about photons, we have 50/% chance of particle A being spin up.
Is it possible to affect the probability of particle A to be spin up ...
- 11
2
votes
1
answer
204
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Example of a classical correlation and a quantum correlation
I'm trying to understand the fundamental differences between classical and quantum correlations through examples of a quantum entangled state and a classically correlated state.
I know that this is an ...
- 39
0
votes
1
answer
55
views
Can quantum interference be detected in entangled pairs?
If I had a pair of entangled particles that were both in superposition, and I put one of them through a interference experiment, such as the double slit experiment, would I see an absence of ...
- 43
0
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4
answers
366
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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 ...
- 623
1
vote
0
answers
173
views
What exactly is meant by the quality of a qubit?
When looking at a quantum annealer, we can see that D-Wave solutions have produced an annealer with over 5000 qubits whilst other companies that take a quantum gate approach have only managed 127 (IBM)...
- 988
2
votes
1
answer
304
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How do three electrons entangle with each other?
In a Quantum entity of two electrons entangled to each other, we know that when one electron's spin is known, then the other electron's spin is the opposite.
But, What's the case in a quantum entity ...
- 21
3
votes
2
answers
338
views
Is there a superposition of two density matrices?
Say I have two density matrices $\rho_0 = \sum_{i,j} \alpha_{i,j} |i\rangle \langle j|$ and $\rho_1 = \sum_{i,j} \beta_{i,j} |i\rangle \langle j|$. What is the density matrix $\rho$ corresponding to ...
- 143
4
votes
1
answer
102
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Easiest way to see that superposition is necessary?
I have been discussing QM with a friend and wanted to explain why holding on to realism means we must accept non-locality.
Essentially I got hung up on explaining Bell's Theorem in simple words.
I ...
- 749
0
votes
1
answer
88
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Bose-Einstein Statistics and Collapse
In Bose-Einstein statistics, two identical bosons can be in one of the following three states with respect to some orthonormal single particle states $|A\rangle$ and $|B\rangle$:
(1) $|A\rangle |A\...
- 1,073
-3
votes
2
answers
113
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Quantum Entanglement and transfer of time information, is it possible? [duplicate]
If two particles are quantum entangled...let’s call them particle A and particle B. You measure the state of particle A.
At this point, can you know the exact time at which the particle B goes from ...
- 109
1
vote
0
answers
246
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How does the superposition of states come up in Bohmian Mechanics?
In Bohmian Mechanics, it assumes a universal wave field in which particle's motion can be calculated using Newton's law of motion:
\begin{equation}
m\frac{d^{2}x}{dt^{2}} = - \nabla(V+U)
\end{...
- 300
4
votes
1
answer
675
views
Connection between spin angular momentum of a photon and circular polarization of light
Do photons have spin angular momentum only if they are part of a circularly-polarized beam?
I suspect that every photon always has spin angular momentum, but in most cases they have a superposition ...
6
votes
4
answers
2k
views
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 ...
- 89
1
vote
1
answer
154
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Is there a way to measure the degree of superposition of a quantum state?
I am wondering if there is a way to calculate the amount of superposition that a quantum state is in. For example, if I have a $2$-qubit quantum system, with basis $\mathcal{B} = \{|00\rangle, |01\...
- 669
3
votes
1
answer
419
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Can post-selecting on the screen in the Delayed Choice Quantum Eraser experiment be used to predict the quantum-eraser measurement results?
I'm curious about QM and spent the last 3 days thinking about Delayed Choice Quantum Eraser (DCQE) experiment, but I couldn't solve this issue:
Assume we do the DCQE experiment so that for the whole ...
- 145
1
vote
0
answers
62
views
Scan Quantum mechanics: Status of current research
I recently stumbled on a new interpretation of Quantum mechanics, called Scan Quantum Mechanics, given by Beatriz Gato-Rivera. She suggests a quantity called quantum inertia, which divides the ...
- 3,134
1
vote
2
answers
160
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Does something prevent superposition at our scale?
I often encounter the argument that quantum mechanics reduces to classical mechanics at sufficiently big scales, as soon as h becomes sufficiently small respect to the actions involved. I clearly ...
- 163
-3
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2
answers
205
views
Do qubits need to be in superposition to be entangled? [closed]
Do qubits need to be in superposition to be entangled?
Put another way, can qubits be entangled but not in superposition?
0
votes
1
answer
37
views
Quantum Computing, and if a Q-bit can be entangled and in superposition at the same time
I was wondering if a Q-bits can be in both entangled and in superposition at the same time?
-3
votes
1
answer
114
views
Never ending quantum superposition? [closed]
So I am wondering over the Copenhagen Interpretation how can a decoherence or measurement ever happen. If in the beginning of the universe everything was in a state of coherence being in ...
0
votes
1
answer
96
views
Do multi-state of entangled particles exists?
I haven't taken any course in Quantum mechanics. But I felt "Quantum Entanglement" quite interesting. I recently read some articles on it. But I am not sure if I understood anything or satisfied with ...
- 393
3
votes
3
answers
256
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Reconciling Understanding of Quantum Entanglement and Superposition
My basic understanding is that Superposition is a property of particles that allow them to behave as if they are in multiple states simultaneously, e.g., interference patterns in double-slit ...
1
vote
2
answers
526
views
What do we know about the composite system vs. its subsystems in an entangled system?
In Susskind's Theoretical Minimum: Quantum Mechanics, he states that, "complete knowledge of a system in classical physics implies complete knowledge of every part of a system" (159). Moreover, he ...
-1
votes
1
answer
376
views
Implications of weak measurement on entanglement
What are the implications of weak-measurement on entangled particles, and how does that resolve the problem of non-superluminal quantum "communication"? If I understand correctly, entangled particles ...
- 101
-1
votes
1
answer
327
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Why is particle superposition still part of quantum mechanics? [duplicate]
After reading an article on Schrodinger's Cat, it seems that if we take the environment as an observer, that superposition cannot occur because all atomic and subatomic entities would be observed all ...
- 21
2
votes
1
answer
454
views
Question on the logic behind quantum computing
According to Wikipedia,
"Quantum computing studies theoretical computation systems (quantum computers) that make direct use of quantum-mechanical phenomena, such as superposition and entanglement, to ...
- 661
0
votes
2
answers
793
views
Is the interference quantum mechanical superposition the same as entanglement? [duplicate]
Are the interference of two wave functions an equivalent way of saying that they are entangled?
- 113
2
votes
3
answers
670
views
How are Superposition and Entanglement related?
How are Superposition and Entanglement related? I don't know much of Quantum Mechanics. I am CSE student and got started with this Quantum Computing. It is interesting! If anybody can help me on this,...
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4
votes
3
answers
17k
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Can Quantum Entanglement and Quantum Superposition be considered the same phenomenon?
Quantum entanglement is known to be the exchange of quantum information between two particles at a distance, while quantum superposition is known to be the uncertainty of a particle (or particles) ...
- 119
2
votes
2
answers
353
views
Quantum Eraser thought experiment with light photons of distinct color
I tried to recreate the Quantum Eraser experiment into a thought experiment with a few changes. It left me a little perplexed as to what outcomes I should expect. Any help would be appreciated.
Lets ...
- 21
6
votes
5
answers
6k
views
Does measuring destroy entanglement
Before measuring a quantum particle(photon) it exists in a superposition state, once we observe(measure) it, it settles in one of the possible states(destroying superposition).
For entangled particles,...
- 387
15
votes
4
answers
5k
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What's the difference between an entangled state, a superposed state and a cat state?
1) Can a state be entangled without also being a superposition? (Please give an example.)
2) Can a state be a superposition without being entangled? (Again, an example please.)
3) And what about ...
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