All Questions
44 questions
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If particles do not have definite properties before measurement in entanglement, what are they? [closed]
It is said that in quantum entanglement, a photon does not have definite properties before measurement. I have two questions.
Is this true for all interpretations of quantum mechanics?
what does it ...
- 12.9k
1
vote
0
answers
54
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SPDC entangled photons and orbital angular momentum?
I know that spontaneous parametric down conversion (SPDC) produces entangled photons in the orbital angular momentum (OAM), i.e., for a pump beam with zero OAM,
$ |\psi \rangle = | 0 0 \rangle + | 1 -...
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15
votes
4
answers
23k
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How do particles become entangled?
A person asked me this and I'm just a lowly physical chemist.
I used a classical analogy. (How good or bad is this and how to fix it?)
Basically, light has a net angular momentum of zero, insofar as ...
-1
votes
1
answer
82
views
How exactly do triple photon entanglements behave? [closed]
I recently learnt that more than two photons can be entangled.
Are all the three photons are expected to have the same polarized angle due to entanglement?
Does measuring one of the three photons ...
- 2,059
0
votes
1
answer
62
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How non-degenerate photon pair can be entangled?
papers like below describe https://arxiv.org/abs/1305.0986 "A Flexible Source of Non-Degenerate Entangled Photons Based on a Two-Crystal Sagnac Interferometer"
I, somehow, thought that ...
- 1,576
1
vote
7
answers
542
views
What is the state of an entangled photon after its twin is absorbed?
Let's two photons are entangled in polarization after a laser beam passes through a Betha Barium Borate crystal. They take different paths and one of them (1) is absorbed in a black sheet. What is the ...
- 36
0
votes
3
answers
635
views
What are the polarizations of an entangled photon pair?
My understanding of polarization of light is that a photon can be horizontally polarized, or vertically polarized, or some angle in between (eg 45 degrees from horizontal) — leaving aside circularly ...
- 1,277
0
votes
2
answers
382
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If photons have no mass, why do they gain mass in photon entanglement?
Photons are massless particles. However, this article states that photons can gain mass when they become entangled. How can this happen?
From the article:
Physicists create new form of light
...
1
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0
answers
134
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Creation of entangled electrons
If one obtains two entangled in polarization photons by parametric down conversion and one of them is accepted by and electron 1 and other by electron 2 - are this electrons now entangled in spin?
- 213k
1
vote
2
answers
149
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Will a two-photon state be detected at the same spot?
Let us say I excite a particular mode $\omega_l$ of the electromagnetic field by means of parametric downconversion such that both of them are identical in all aspects: polarisation, direction and of ...
- 15.2k
1
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0
answers
62
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Will an entangled photon bouncing off a/penetrating through a mirror "de-tangle" it?
Lets say I create a pair of entangled photons. I then shoot one of the photons through a semi-silvered(semi-reflecting) mirror. one(or both) of the photons are reflected, and (or) one (or both) of the ...
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3
votes
4
answers
4k
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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 ...
2
votes
1
answer
92
views
Can Compton scattering generate entangled photons and electrons?
Since the Compton scattering process is where a high energy photon scatters off an electron, would it be a plausible result for the energies of the scattered photon and the scattered electron to be ...
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1
vote
2
answers
425
views
Entanglement in double slit experiment
Suppose we send 2 entangled photons through the 2 slit, does measuring the position of one of the photons affect the other particle's wave function or does the other particle still behave as a wave ?
- 235k
0
votes
1
answer
72
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Coupling of photons and SC qubits in circuit QED
I have been going through a number of articles to understand quantum circuits.I am trying to understand how a qubit gets coupled with the photons? But I am only getting answers of how a qubit gets ...
- 377
1
vote
1
answer
519
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How does interference occur in interferometers?
The Mach-Zehnder interferometer (FIG. 1) is constituted by two arms. It is said to be (un)balanced if the two arms have (un)equal lengths. The difference in lengths generates different interference ...
- 25.3k
1
vote
1
answer
646
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How do scientists produce entangled photons?
In many experiments like the Delayed Choice Quantum Eraser Experiment, scientists use entangled photons.
How do scientists make/obtain them?
What is the realistic level of control scientists have ...
- 213k
4
votes
3
answers
1k
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Faster-Than-Light Communication using Entangled Photons [duplicate]
Based on my understanding of the “Double-Slit Quantum Eraser Experiment”, documented here: http://grad.physics.sunysb.edu/~amarch/, it seems that Faster-Than-Light communication is possible. Of ...
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1
vote
0
answers
23
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Quantum eraser: How does photon detection in an interference pattern "dark spot" not affect the state of the remaining photon? [duplicate]
I have read time and time again that there is nothing mysterious going on in the quantum eraser experiment, but I can't get the math to add up. Please help me: Consider these two simplified ...
- 2,785
2
votes
2
answers
199
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Entanglement Observation
I'm thinking that light slows down in a medium because photons are being absorbed and then remitted by atoms or molecules in the beam. This would imply that the photons which leave a lens or filter ...
- 10.8k
18
votes
2
answers
3k
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Is the photon pair generated from the electron-positron annihilation entangled?
Is the photon pair generated from the electron-positron annihilation entangled?
And would they work as a source of entangled photons suitable for experiments in quantum optics?
- 1,321
7
votes
2
answers
798
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Is this news article about quantum radar legit? [duplicate]
From https://www.digitaltrends.com/cool-tech/quantum-radar-stealth-aircraft/
In principle, a quantum radar functions like a regular radar — only
that instead of sending out a single beam of ...
- 11.5k
1
vote
1
answer
179
views
Is photon's direction entangled?
Consider a free electron, with photon, that runs to electron under some angle(as everybody says). Compton scattering is happening, and electron instantly reemits photon in different angle.
First, ...
- 213k
4
votes
2
answers
685
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Temporal delay between entangled photon pair
When generating entangled photons by means of Spontaneous Parametric Down-Conversion SPDC, the usual assumption is that the two photons are created at the same time. I have not been able to find any ...
- 235k
2
votes
2
answers
687
views
Is it possible to create an entangled pair of photons if they originate initially from operations at two separate sites?
My question is whether or not it would be possible to create an entangled state between two photons that do not share the same initial photon source and their respective sources are separated by an ...
- 99
-3
votes
1
answer
111
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Predicted correlations of entangled particles [closed]
I get conflicting answers but as far as I can tell, quantum mechanics predicts photon correlations would be 50 percent of the time. Is this correct and would correlations of entangled electrons be the ...
- 4,519
3
votes
1
answer
1k
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Is it possible to create a pair of polarized, polarization-entangled photons?
Is there a light source which emits (mostly) polarization-entangled pairs of photons that have a known polarization angle, e.g. a certain angle in relation to the orientation of the source?
Applying ...
- 1,057
1
vote
0
answers
93
views
Entangled Photons Emited from Stars
Do starts emit entangled photons? If so, how do you calculate the percentage of photons that are entangled?
What are the mechanisms that would cause a star to emit entangled photons?
- 1,405
9
votes
2
answers
1k
views
Why is a nonlinear crystal necessary to stimulate quantum fluctuations that entangle photons?
I've been reading about spontaneous parametric down conversion (SPDC). The Wikipedia article on it says:
A nonlinear crystal is used to split photon beams into pairs of photons that, in accordance ...
- 135k
-1
votes
3
answers
352
views
Are entangled photon particles really entangled?
If an entangled pair of photons are measured they both display the same polarity. Why is this considered entanglement and not simply a coincidence that the photon was polarized by the same crystal? My ...
- 4,519
0
votes
2
answers
529
views
Does a normal torch emit entangled photons?
I was reading a sciencenews.org post about three photons being entangled. My question here is, why is the chance of producing an entangled pair once in a billion times? Isn't every particle produced ...
CommunityBot
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0
votes
4
answers
135
views
Can someone put entanglement in laymens terms? [duplicate]
Can someone put entanglement in laymens terms? I understand that photon spin affects an entangled photon across any distance, what I don't understand is how spin works, does a photon only have "spin ...
CommunityBot
- 1
1
vote
0
answers
47
views
Can we realize a super multi-photons entanglement system? [closed]
Can we find a method to generate super multi-photons entanglement by implementing a special operation which can realize the union of two multi photons entanglement systems ?
For example , there have ...
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-2
votes
1
answer
108
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Quantum Entanglement- why are we so suprised? [duplicate]
So, I was watching a youtube video in order to understand quantum entanglement- you know, as a non-physicist- and at one point the speaker says that it doesn't understand how the energy of one photon ...
- 135k
2
votes
1
answer
2k
views
How do scientists entangle photons? [closed]
How do scientists entangle photons? One documentary I watched said that scientists can transport a single photon by entangling 2 other photons and somehow they are able to "teleport" them. How is it ...
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0
votes
2
answers
305
views
What is entanglement really about? [closed]
I am a beginner in this field, I am trying to understand the basics of Quantum Mechanics, I want straightforward answers to few questions on entangled photon/electron:
1- What entangled photons ...
- 7,295
0
votes
1
answer
103
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Is linear polarization of entangle photons in 2-particle decay always correlated?
In Aspect's paper "Bell's Theorem: The naive..." and in an 2002 AJP article by Dehlinger and Mitchell "Entangled photon apparatus..." the photons are described to be in the $|xx\rangle+|yy\rangle$ ...
0
votes
2
answers
273
views
Pair Production in Entangled Photons
Two high-energy photons are entangled and go their separate ways. One of them undergoes pair production by interacting with an atomic nucleus, and this is observed. Does the other photon also undergo ...
- 25.9k
2
votes
2
answers
353
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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 ...
CommunityBot
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-2
votes
1
answer
791
views
Does this experiment on wave-particle duality and complementarity disprove quantum mechanics and prove the EPR viewpoint on it?
I recently read
Photons act like they go through two paths, even when we know which they took, at Ars Technica,
which reports on the paper
Wave-particle dualism and complementarity unraveled by ...
CommunityBot
- 1
0
votes
2
answers
103
views
Can a two-levels photon pair be created either entangled or not entangled? [closed]
I am learning about experiments on Quantum Optics and Quantum Tomography in order to understand how to measure two qubits with an arbitrary quantum state of their polarization degrees of freedom. ...
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12
votes
1
answer
887
views
How to tell whether photons are entangled?
Suppose you have some sort of a "black box" system - you know nothing of its inner workings. The system has two outputs, let's call them A and B, and it occasionally emits photons - one photon from ...
- 509
2
votes
2
answers
501
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Why are results of Bell's experiments considered to "break realism"?
Related to my previous question (Why would classical correlation in Bell's experiment be a linear function of angle?), as a newbie in quantum mechanics, I am also unable to find the reason to why ...
CommunityBot
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2
votes
1
answer
193
views
Is it possible to send a single photon from a distant planet (say Mars) and detect its arrival at a site on Earth?
My question is specifically whether there exists a technique by which a single photon can be "tagged" or "encoded" in such a way that it can traverse our atmosphere and arrive at some sort of detector ...
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