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Fri Aug 7, 2020, 02:19 PM

Physicists watch quantum particles tunnel through solid barriers. Here's what they found.


By Diane Lincoln - Live Science Contributor 5 hours ago



The quantum world is a pretty wild one, where the seemingly impossible happens all the time: Teensy objects separated by miles are tied to one another, and particles can even be in two places at once. But one of the most perplexing quantum superpowers is the movement of particles through seemingly impenetrable barriers.

Now, a team of physicists has devised a simple way to measure the duration of this bizarre phenomenon, called quantum tunneling. And they figured out how long the tunneling takes from start to finish ó from the moment a particle enters the barrier, tunnels through and comes out the other side, they reported online July 22 in the journal Nature.

Quantum tunneling is a phenomenon where an atom or a subatomic particle can appear on the opposite side of a barrier that should be impossible for the particle to penetrate. It's as if you were walking and encountered a 10-foot-tall (3 meters) wall extending as far as the eye can see. Without a ladder or Spider-man climbing skills, the wall would make it impossible for you to continue.

However, in the quantum world, it is rare, but possible, for an atom or electron to simply "appear" on the other side, as if a tunnel had been dug through the wall. "Quantum tunneling is one of the most puzzling of quantum phenomena," said study co-author Aephraim Steinberg, co-director of the Quantum Information Science Program at Canadian Institute for Advanced Research. "And it is fantastic that we're now able to actually study it in this way."

More:
https://www.livescience.com/quantum-tunneling-observed-and-measured.html

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Reply Physicists watch quantum particles tunnel through solid barriers. Here's what they found. (Original post)
Judi Lynn Aug 2020 OP
judesedit Aug 2020 #1
qazplm135 Aug 2020 #4
Jim__ Aug 2020 #7
qazplm135 Aug 2020 #8
Jim__ Aug 2020 #9
qazplm135 Aug 2020 #10
Jim__ Aug 2020 #11
qazplm135 Aug 2020 #13
Jim__ Aug 2020 #15
qazplm135 Aug 2020 #16
Jim__ Aug 2020 #17
qazplm135 Aug 2020 #18
Jim__ Aug 2020 #19
qazplm135 Aug 2020 #20
qazplm135 Aug 2020 #29
Bernardo de La Paz Aug 2020 #48
qazplm135 Aug 2020 #49
Bernardo de La Paz Aug 2020 #50
qazplm135 Aug 2020 #51
Bernardo de La Paz Aug 2020 #52
qazplm135 Aug 2020 #53
Bernardo de La Paz Aug 2020 #54
qazplm135 Aug 2020 #55
Bernardo de La Paz Aug 2020 #56
qazplm135 Aug 2020 #58
judesedit Aug 2020 #22
qazplm135 Aug 2020 #28
Bernardo de La Paz Aug 2020 #47
qazplm135 Aug 2020 #57
qazplm135 Aug 2020 #59
judesedit Aug 2020 #21
Jim__ Aug 2020 #24
qazplm135 Aug 2020 #30
Jim__ Aug 2020 #33
qazplm135 Aug 2020 #34
Jim__ Aug 2020 #35
qazplm135 Aug 2020 #36
Jim__ Aug 2020 #37
qazplm135 Aug 2020 #38
Jim__ Aug 2020 #39
qazplm135 Aug 2020 #40
SkyDaddy7 Aug 2020 #45
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qazplm135 Aug 2020 #12
Wounded Bear Aug 2020 #2
Karadeniz Aug 2020 #3
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qazplm135 Aug 2020 #31
judesedit Aug 2020 #23
CaptainTruth Aug 2020 #27
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CaptainTruth Aug 2020 #42
qazplm135 Aug 2020 #43
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burrowowl Aug 2020 #63

Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 02:29 PM

1. Possibly it's evaporating and reorganizing on the other side

Like beaming up. Or apparitions walking through walls. Is that possible? There's so much we don't know. I just like to think about that stuff. It's fascinating. Isn't that what they tried to accomplish with the Philadelphia Experiment?

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Response to judesedit (Reply #1)

Fri Aug 7, 2020, 02:50 PM

4. there's a range of probabilities

of where it could be. A tiny number of those probabilities just so happen to be on the other side of the wall.

Give enough time (or enough atoms) and the numbers align for some of them to "just so happen to be on the other side of the wall."

So, that's where they end up.

They aren't evaporating or reorganizing and they aren't passing through. It's just one of the probabilities of the next point on their journey, just as if they were moving down the tube. They are just "There" just like they would be if they were moving down the tube.

I would guess the .6 milliseconds it took to "cross" would have been the same time it would have taken them to cross a similar distance within the tube. But I can't tell from the article if they are looking at it like that.

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Response to qazplm135 (Reply #4)

Fri Aug 7, 2020, 05:02 PM

7. If they just appear on the other side, how would you explain the precession?

My understanding of the article is that they will only precess when they are inside the barrier:

Subatomic particles all have magnetic properties and when magnets are in an external magnetic field, they rotate like a spinning top. The amount of rotation (also called precession) depends on how long the particle is bathed in that magnetic field. Knowing that, the Toronto group used a magnetic field to form their barrier. When particles are inside the barrier, they precess. Outside it, they don't. So measuring how long the particles precess told the researchers how long those atoms took to tunnel through the barrier.

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Response to Jim__ (Reply #7)

Fri Aug 7, 2020, 05:07 PM

8. because the magnetic field is only inside the barrier

the magnetic field is not causing the tunneling and neither is the precession. It happens regardless but this allows them to measure the time.

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Response to qazplm135 (Reply #8)

Fri Aug 7, 2020, 05:17 PM

9. Doesn't the precession imply that they're actually passing through the barrier?

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Response to Jim__ (Reply #9)

Fri Aug 7, 2020, 05:23 PM

10. your own link

"So measuring how long the particles precess told the researchers how long those atoms took to tunnel through the barrier."

I don't see any linkage in there that says the precession tells you it's passing through the barrier physically. It simply measures the time it takes to go from inside to outside. That does not equate to "passing through."

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Response to qazplm135 (Reply #10)

Fri Aug 7, 2020, 05:29 PM

11. From my link: "When particles are inside the barrier, they precess. Outside it, they don't."

That's what I'm taking as meaning precession implies the particles passed through the barrier.

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Response to Jim__ (Reply #11)

Fri Aug 7, 2020, 05:35 PM

13. no it doesn't

it simply says this is the mechanism to tell us how long this process works. It does not say, this is how we know it actually passed through the barrier.

"While the laws of quantum mechanics allow for quantum tunneling, researchers still don't know exactly what happens while a subatomic particle is undergoing the tunneling process."

"In many interpretations of quantum mechanics, it is impossible ó even in principle ó to determine a subatomic particle's trajectory."

Is it possible that one day we will learn that it actually does "burrow" through in spite of our belief that burrowing through is impossible? Sure. It would require a fundamental rewriting of physics if objects with mass can simply pass through other objects with mass with no interactions (and one of the objects not be dark matter or I suppose a neutrino). But sure, lots we don't know.

But as it stands right now? This experiment does not get there. It just tells us how long the process works.

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Response to qazplm135 (Reply #13)

Fri Aug 7, 2020, 05:53 PM

15. OK. I can't argue about quantum theory. But the article does talk about the velocity of the ...

... atoms inside the barrier.

Experiments exploring quantum tunneling are difficult and further research is needed to understand the implications of this study. The Toronto group is already considering improvements to their apparatus to not only determine the duration of the tunneling process, but to also see if they can learn anything about velocity of the atoms at different points inside the barrier. "We're working on a new measurement where we make the barrier thicker and then determine the amount of precession at different depths," Steinberg said. "It will be very interesting to see if the atoms' speed is constant or not."

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Response to Jim__ (Reply #15)

Fri Aug 7, 2020, 06:27 PM

16. I don't know what else to tell you

You seem determine to believe it t says what it doesn't say.

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Response to qazplm135 (Reply #16)

Fri Aug 7, 2020, 06:57 PM

17. My belief is based on explicit statements in the article.

For clarity:

When particles are inside the barrier, they precess. Outside it, they don't.


The particles are precessed.

And - my bolding:

... The Toronto group is already considering improvements to their apparatus to not only determine the duration of the tunneling process, but to also see if they can learn anything about velocity of the atoms at different points inside the barrier. "We're working on a new measurement where we make the barrier thicker and then determine the amount of precession at different depths," Steinberg said. "It will be very interesting to see if the atoms' speed is constant or not."


Your posts haven't given me any reason not to believe that those statements mean what I think they do.

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Response to Jim__ (Reply #17)

Fri Aug 7, 2020, 07:29 PM

18. yes INSIDE

because they specifically SET IT UP THAT WAY SO THAT THEY COULD MEASURE the time.

It has NOTHING to do with quantum tunneling. They would have quantum tunneled with or without the precession.

Yes, they want to SEE if it takes LONGER to go through thicker barriers. That does NOT mean they actually physically passed through the barriers. it takes TIME to move any distance, if you increase the distance, it will take more time.

The VERY SAME ARTICLE tells you we dont. know. how. quantum. tunneling. works.

But you've ignored that to fixate on your belief that it literally tunnels through solid matter.

I'm done. Your belief isn't based on explicit statements, it's based on a complete misunderstanding of what those statements are and are not saying.

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Response to qazplm135 (Reply #18)

Fri Aug 7, 2020, 08:06 PM

19. Yes, inside: "... if they can learn anything about velocity of the atoms ...

... at different points inside the barrier"

I never said, nor did I ever think, the precession caused the tunneling. If you believe I have made such a statement, please cite where I said that.

Yes, they want to SEE if it takes LONGER to go through thicker barriers. That does NOT mean they actually physically passed through the barriers. it takes TIME to move any distance, if you increase the distance, it will take more time.


Twice now I have cited the article explicitly talking about the velocity of the atoms at different points inside the barrier. You have not responded to that. Once again:

The Toronto group is already considering improvements to their apparatus to not only determine the duration of the tunneling process, but to also see if they can learn anything about velocity of the atoms at different points inside the barrier.


And, yes, they're talking about increasing the size of the barrier; and they're also talking about checking to see whether the atoms' speed is constant or not:

"We're working on a new measurement where we make the barrier thicker and then determine the amount of precession at different depths," Steinberg said. "It will be very interesting to see if the atoms' speed is constant or not."


The VERY SAME ARTICLE tells you we dont. know. how. quantum. tunneling. works.


Yes, I am well aware that no one knows how quantum tunneling works. I did not say anything to contradict that. Aephraim Steinberg, one of the authors of the paper, talks about the velocity of the atom inside the barrier. He's not claiming to know how quantum tunneling works, but he is talking about the velocity of the atoms inside the barrier.

I haven't ignored anything. I have responded to explicit statements in your posts.


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Response to Jim__ (Reply #19)

Fri Aug 7, 2020, 08:09 PM

20. to also see if they can learn anything

do you understand that means they don't know? do you think the part of the article that LITERALLY says "we don't know how QT works" was just extra words they threw in there for no reason?

Or do you think, I don't know, maybe, it means, we don't know how QT works?

I'm done. This is futile.

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Response to Jim__ (Reply #19)

Fri Aug 7, 2020, 11:47 PM

29. you clearly don't understand

you just keep repeating the same things you don't understand, and I have no inclination to try anymore.

If atoms were actually burrowing through the wall, then quantum tunneling wouldn't be a thing. It would be something completely different that would violate the current laws of physics and would be a HUGE deal. You'd have mass, passing through other mass, like your hand phasing through a wall. If that's what it was, then we'd just say, oh look, it looks like if the particles are small, they can pass through a wall of other particles.

Of course, we know that doesn't work, because we can't shine a light through a wall, and photons are pretty freaking small.

But heck, believe what you want.

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Response to qazplm135 (Reply #29)

Wed Aug 12, 2020, 01:08 PM

48. You clearly didn't read the article clearly. The barrier was NOT a mass. It was magnetic. . . . nt

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Response to Bernardo de La Paz (Reply #48)

Wed Aug 12, 2020, 01:16 PM

49. The reason why you can't burrow through a wall

Is BECAUSE of magnetism or rather charge. That's why a magnetic field can stand in for a wall or wire or whatnot. It's not burrowing through regardless.

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Response to qazplm135 (Reply #49)

Wed Aug 12, 2020, 01:30 PM

50. You claimed it was because it had mass. It does not have mass. . . . nt

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Response to Bernardo de La Paz (Reply #50)

Wed Aug 12, 2020, 01:35 PM

51. I was talking about quantum tunneling in general

I wasn't claiming it was "because" it has mass, but having mass means having atoms and that means electrons and that means you can't pass through.

The barrier simulates that.

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Response to qazplm135 (Reply #51)

Wed Aug 12, 2020, 01:41 PM

52. You wrote it was impossible to be in the barrier because of MASS. Further, photons aren't affected


Photons aren't affected by mass or charge.

10 cm of glass has more mass than 0.1 mm aluminum foil.

You wrote:

Is it possible that one day we will learn that it actually does "burrow" through in spite of our belief that burrowing through is impossible? Sure. It would require a fundamental rewriting of physics if objects with mass can simply pass through other objects with mass with no interactions (and one of the objects not be dark matter or I suppose a neutrino). But sure, lots we don't know.

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Response to Bernardo de La Paz (Reply #52)

Wed Aug 12, 2020, 01:55 PM

53. Sigh

I was using shorthand and you know it. I'm also going to guess that you also don't think it "burrows" through but you can't turn down the chance to try and nitpick.

And photons aren't affected by mass? Really? Gravity bends light.
Not affected by charge? Hello, polarization.

They don't HAVE mass or charge, that doesn't mean they aren't "affected" by mass or charge.

Now, ordinarily I'd just good naturedly assume you knew that and were just, ya know, using shorthand, but since you wanna nitpick...

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Response to qazplm135 (Reply #53)

Wed Aug 12, 2020, 02:03 PM

54. Quantum gravity not been proven, so, no, mass does not affect transmission of photons through mass.


Dielectric polarization of charge is very different from polarization of electromagnetic waves/particles.

For example, charge is not mentioned at all in the Wikipedia article on polarization of waves. It operates in other ways.

https://en.wikipedia.org/wiki/Polarization%5F%28waves%29

10 cm of glass does not have the same mass as a star bending light. The star is bending space-time.

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Response to Bernardo de La Paz (Reply #54)

Wed Aug 12, 2020, 02:16 PM

55. Einstein??

What bends spacetime? Mass. Thus, light is affected by mass.

Light is absorbed by mass. It's why radio waves make it through and light does not.

Mass affects light in MULTIPLE ways.

And yes 10 cm of glass will affect light in multiple ways as well, from it's mass (even if a tiny tiny tiny bit), and from refraction/reflection.

The photoelectric effect comes from light interacting with electrons, which last time I checked, was a charged particle.

https://van.physics.illinois.edu/qa/listing.php?id=2348&t=photons-as-carriers-of-the-electromagnetic-force
"Photons, real and virtual, are emitted and absorbed by charged particles, even though they are not charged themselves. They only interact with charged particles, and not with each other. Thatís why photons donít interact with magnetic fields -- the photons which make up the magnetic field are not charged so other photons cannot interact with them."

From your own link:
"An electromagnetic wave such as light consists of a coupled oscillating electric field and magnetic field which are always perpendicular to each other; by convention, the "polarization" of electromagnetic waves refers to the direction of the electric field. In linear polarization, the fields oscillate in a single direction. In circular or elliptical polarization, the fields rotate at a constant rate in a plane as the wave travels."

Your statement about charge is only true in a STATIC magnetic field. You made a general statement that has a clear specific situation when it isn't true.

So, you going to stick with "light isn't affected by charge or mass" still? Really? All so you can claim internet nitpicking victory?
Clearly the answer is yes.

But tell me, does an electron tunnel through in quantum tunneling or not? Because if you answer no, which is what all accepted science says today is the correct answer, then all of this is nitpicking BS. And if you answer no, then you are basically BSing about all of it.



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Response to qazplm135 (Reply #55)

Wed Aug 12, 2020, 02:19 PM

56. So now you are against people making "general statements" the way you made general statements.




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Response to Bernardo de La Paz (Reply #56)

Wed Aug 12, 2020, 02:28 PM

58. lol

see how that works?

You don't like it anymore than I do.

Difference is I was CLEAR that ordinarily I don't act that way, and don't nitpick...but since you decided to start it, I went with it, and was clear that I went with it.

So your call, we can nitpick some more, or we can assume each of us has some basic knowledge, not act like an asshole, and continue on...or not, don't really care.

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Response to qazplm135 (Reply #13)

Fri Aug 7, 2020, 09:44 PM

22. From what I've read about quantum physics, there is no solid mass

Just atoms held together magnetically or through like a cell intelligence.

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Response to judesedit (Reply #22)

Fri Aug 7, 2020, 11:43 PM

28. for the purpose of this

it is. It's not solid in the sense of "no space" but it is solid in the sense that your hand can't pass through a wall even though both are mostly "empty space." Those darn probability field dispersed electrons in your hand keep it from passing the ones in the wall. Same principle here with quantum tunneling.

That's why quantum tunneling is such a mystery. You CAN'T just burrow your way through. If you could, it wouldn't be a big deal.

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Response to qazplm135 (Reply #13)

Wed Aug 12, 2020, 01:04 PM

47. 1) Rubidium atoms are not "subatomic", 2) Precession only occurs inside the barrier


If they only "appear" on the other side without ever having been inside the barrier, then they would not have precessed.

The barrier was magnetic, not massive.

Therefore, they spent time (0.6 milliseconds) inside the barrier.

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Response to Bernardo de La Paz (Reply #47)

Wed Aug 12, 2020, 02:26 PM

57. they "precess" inside the barrier

because they are made to do so inside the barrier. They then measured how long they precessed and used that to determine how long it took to make it outside the barrier.

So you too think they "Burrowed" through the barrier lol that explains it.

That does not, in spite of claims otherwise, mean they actually burrowed through.

They could have been in a state of superposition both inside and outside the barrier, or it could simply be that change in probability between being inside and outside does not occur "instantaneously" which I've never believed was true as nothing in nature happens "instantaneously" in my mind.

Comment from the article puts it perfectly:
"It is easier to think of the elementary particles as particles of their quantum fields at first. The field penetrates the barrier but there is no probability current inside the barrier, there is no observable particle inside the volume https://en.wikipedia.org/wiki/Probability_current ] but it is its wave function (describing the particle probability amplitude) that has been delocalized over the barrier https://en.wikipedia.org/wiki/Quantum_tunnelling ].

Pulling that back to the atom, if it tunnels as a coherent system - as we can see it does - I doubt you can say it existed - was observable - in the common sense definition during the tunneling time."

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Response to Bernardo de La Paz (Reply #47)

Wed Aug 12, 2020, 02:33 PM

59. by the way, another experiment "Definitively" found it was near instantaneous

http://www.sci-news.com/physics/quantum-tunneling-07016.html


I'm going to guess those folks aren't in agreement that it "tunnels" through.

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Response to Jim__ (Reply #9)

Fri Aug 7, 2020, 09:38 PM

21. I probably sound stupid, but you mean kind of like a drill?

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Response to judesedit (Reply #21)

Fri Aug 7, 2020, 11:06 PM

24. I was referring to a paragraph in the article.

Subatomic particles all have magnetic properties and when magnets are in an external magnetic field, they rotate like a spinning top. The amount of rotation (also called precession) depends on how long the particle is bathed in that magnetic field. Knowing that, the Toronto group used a magnetic field to form their barrier. When particles are inside the barrier, they precess. Outside it, they don't. So measuring how long the particles precess told the researchers how long those atoms took to tunnel through the barrier.


Specifically to these 2 sentences: When particles are inside the barrier, they precess. Outside it, they don't.

The way I read those sentences, the particles will not precess unless they pass inside the barrier. It was that paragraph that raised the question with me.

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Response to Jim__ (Reply #24)

Fri Aug 7, 2020, 11:50 PM

30. you are fixated on the precession

which has nothing to do with why they tunnel. Nothing. Nada. Zilch. It's simply a means of determining the TIME they spend inside the barrier until they are outside the barrier. They precess inside because that's how the experiment was designed to determine the time frame.

Do you think particles in normal space don't take time to cross space? Why wouldn't they take time in this scenario too? All this experiment tells us is that it takes some amount of time, that it's not instantaneous. It does not tell us that the particles are literally burrowing through the wall. It doesn't tell us anything about how they go from being inside to being outside. The article itself tells us that.

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Response to qazplm135 (Reply #30)

Sat Aug 8, 2020, 12:42 AM

33. "When particles are inside the barrier, they precess. Outside it, they don't."

The particles are precessed. I'm not saying that causes them to tunnel. The precession is an indication that they were inside the barrier. When particles are inside the barrier, they precess. Outside it, they don't.

You're all hung up on something that I am not saying.

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Response to Jim__ (Reply #33)

Sat Aug 8, 2020, 12:59 AM

34. so what?

Why do you think it matters that they precess inside the barrier and don't outside the barrier?

To what is that relevant that you keep repeating it over, and over, and over, and over?

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Response to qazplm135 (Reply #34)

Sat Aug 8, 2020, 01:02 AM

35. That means they were inside the barrier.

My original question in post #7:

If they just appear on the other side, how would you explain the precession?

My understanding of the article is that they will only precess when they are inside the barrier:

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Response to Jim__ (Reply #35)

Sat Aug 8, 2020, 01:23 AM

36. No

They were inside the barrier regardless. The precession was added to do something. What?

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Response to qazplm135 (Reply #36)

Sat Aug 8, 2020, 01:41 AM

37. They were inside the barrier regardless?

From the article my bolding:

Quantum tunneling is a phenomenon where an atom or a subatomic particle can appear on the opposite side of a barrier that should be impossible for the particle to penetrate. It's as if you were walking and encountered a 10-foot-tall (3 meters) wall extending as far as the eye can see. Without a ladder or Spider-man climbing skills, the wall would make it impossible for you to continue.


And, once again from post #7, my original question:

If they just appear on the other side, how would you explain the precession?

My understanding of the article is that they will only precess when they are inside the barrier:


So, I guess my original understanding was correct; they only precess when they are inside the barrier. That was what I asked about.

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Response to Jim__ (Reply #37)

Sat Aug 8, 2020, 09:11 AM

38. Again you are obsessed with the precession

It has nothing to do with quantum tunneling.

The precession is nothing more than a trick they use to identify the period of time elapsed from inside to outside.

If they didn't do it, they would STILL sometimes go outside the barrier in exactly the same way and frequency.

Replace precession with they stuck a tiny person on the atoms with a tiny clock to tell them the time between being inside and outside the barrier.

Other experiments have also tried to measure this time. They didn't use this trick, they used other tricks. This experiment tried this trick for the first time and claim they've gotten an accurate measurement. That's it.

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Response to qazplm135 (Reply #38)

Sat Aug 8, 2020, 10:45 AM

39. No, I'm not obsessed with precession.

I asked a simple question and have repeated that simple question more than once. You couldn't answer it. Fine.

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Response to Jim__ (Reply #39)

Sat Aug 8, 2020, 03:05 PM

40. I've REPEATEDLY answered it

frustratingly so.

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Response to qazplm135 (Reply #40)

Tue Aug 11, 2020, 11:42 AM

45. YIKES!

...I can't believe I'm asking a question about Quantum particles but here goes...

...I read your entire conversation above & I THINK I may be grasping what the article & you are saying? And I'm not going to be able to explain this correctly but I will try...So, Quantum Theory is based on probabilities & this applies to the observed phenomenon of Quantum Tunneling...It happens but it is rare.

...So, all this experiment was set up to do was to try & accurately measure the time in which it would take atoms to pass through an impassable barrier, a magnetic field, and used the precession of the atoms simply as a means of accurately timing this process?

...Am I even close?

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Response to SkyDaddy7 (Reply #45)

Tue Aug 11, 2020, 11:58 AM

46. This is where I need a sarcasm detector

Because mine is blinking red right now lol

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Response to Jim__ (Reply #7)

Fri Aug 7, 2020, 05:31 PM

12. I would note that saying something

"just appears" implies teleportation.

Every moment along a path there's a variety of places a particle can be.

Think of an electron. It isn't flowing along a single set path around the nucleus. It's spread out in a probability cloud.

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Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 02:35 PM

2. Cool stuff! Thanks for the link...nt

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Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 02:44 PM

3. Amazing! Thanks for sharing!

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Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 02:51 PM

5. Richard Feynman- "If you think you understand quantum mechanics, you don't understand quantum mechan

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Response to TrogL (Reply #5)

Fri Aug 7, 2020, 04:14 PM

6. This!!

I'll leave it up to the smarter people to prove it.

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Response to TrogL (Reply #5)

Fri Aug 14, 2020, 02:01 PM

61. I used to use quantum tunneling diodes. They were incredibly fast.

The only real limit on their switching speed was the physical distance between their electrical contacts.

Also, flash memory (e.g. USB thumb drive or camera memory card) is based on tunneling.

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Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 05:49 PM

14. Particles can appear from empty space...

Last edited Fri Aug 7, 2020, 11:07 PM - Edit history (1)

... over extremely brief time, basically "borrowing" the energy before disappearing again, which is allowed by nature from Heisenberg's Uncertainty Principle. So that's a similar example of the strange behavior of tiny particles.

I suspect it's folly to try too hard to explain it in terms that are more familiar to our senses in the macro-world. It's behavior of small particles that has been observed and verified many times, so I just accept it and try to not get too philosophical about it.

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Response to Buckeye_Democrat (Reply #14)

Fri Aug 7, 2020, 11:30 PM

25. Hence we have Hawking radiation emitted by black holes.

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Response to CaptainTruth (Reply #25)

Fri Aug 7, 2020, 11:38 PM

26. Yep!

I think the math indicates it will happen more frequently near black holes too, in the heavily-warped space.

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Response to Buckeye_Democrat (Reply #14)

Fri Aug 7, 2020, 11:51 PM

31. virtual particles

yes. You can get something from nothing so long as you get nothing again at the end, which you get from the particle-antiparticle virtual pairs mutually annihilating (except obviously with Hawking radiation).

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Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 09:47 PM

23. Thank you for the food for thought. It really is a fascinating subject

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Response to Judi Lynn (Original post)

Fri Aug 7, 2020, 11:42 PM

27. Interesting. According to one of the books I read (by Brian Greene? Roger Penrose?)...


... I thought when a particle tunneled it didn't actually travel through the space it "tunneled" through. From the particle's perspective that space simply didn't exist, so the tunneling was instantaneous. This article implies that the tunneling isn't instantaneous, it takes some time.

The last physics/cosmology books I read are several years old now, so it appears more has been learned.

Fascinating stuff. It's fun to read about M-theory at bed time & try to wrap your brain around it as you fall asleep.

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Response to CaptainTruth (Reply #27)

Fri Aug 7, 2020, 11:56 PM

32. Yes, it doesn't tunnel through

but not tunneling doesn't have to mean that moving from one side to the other is instantaneous.

Much of nature isn't continuous. It's in quanta, blocks. Particles don't necessarily touch every available "space" on a journey from point A to point B. Particularly when they are tiny and already behaving like a probability wave. So we know it takes time for a current of electrons to flow down X length of wire. But that doesn't mean the electron "touches" every point along a set path. It's still spread out in a probability wave.

It still takes time to move from one area to another area.

I don't think this is necessarily any different.

What I would like to see is a comparison between the distance the electrons are found outside the barrier and the time traveled with the expected time for a similar distance "down" the wire so to speak. I suspect it's going to be similar. The thing that trips people up is that it's a probability wave inside too. We are used to macro thinking. Something has a set position at a set time. If it moves from point A to point B, it must follow a set path. But at the quantum level, that's not true.

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Response to qazplm135 (Reply #32)

Sun Aug 9, 2020, 11:19 PM

42. Thanks for the reply. Perhaps I should have said "continuous."


Again, from the (admittedly old) books I last read, the travel of the particle was continuous down its "path." It's just that relative to our frame of reference, time & space as we perceive it, the particle experienced space differently. There was a chunk of space that we perceived (& we would have to travel through to get from Point A to Point B) that the particle didn't have to travel through. For that particle, that bit of space simply didn't exist.

And, just FYI, after I got my engineering degree & studied subatomic particle physics (general dynamics) with graduate studies in stochastic systems & probability theory, I went on to a lifetime of studying cosmology as a "hobby."

All of which makes me wonder... you correctly point out probably theory & the uncertainty principal, & it makes me wonder if what was observed wasn't tunneling at all? What if it was purely wave equations & probability? Which is why it wasn't "continuous" (instantaneous)?

I'd have to look at the width of the "barrier" & the energies involved & do some math ... just a late night thought.

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Response to CaptainTruth (Reply #42)

Mon Aug 10, 2020, 12:14 AM

43. I agree it isn't "tunneling" in the sense

of burrowing through.

I think it is exactly what you say, that it is simply probability and wave equations.

The "macro" result is that it goes through a barrier it shouldn't be able to, i.e. it "tunnels" through, but the quantum effect is it simply ended up on one of the probability wave positions that happened to be on the other side of the barrier. That wasn't instantaneous (I don't think anything in nature is-Planck Time and whatnot), it took a period of time, which they happened to measure with an ingenious experiment.

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Response to Judi Lynn (Original post)

Sat Aug 8, 2020, 11:37 PM

41. Made me think of this

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Response to Judi Lynn (Original post)

Wed Aug 12, 2020, 02:48 PM

60. Particles with superpowers

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Response to Judi Lynn (Original post)

Sun Aug 16, 2020, 08:31 PM

62. Once again, thanks for or a challenging but fascinating post. nt

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Response to Judi Lynn (Original post)

Wed Aug 19, 2020, 02:16 PM

63. Thanks for link

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