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a reply to: Arbitrageur

I've just watched that quantum eraser vid.

It seems to be rather confusing. As if they are either ignorant. Or doing it on purpose.

They are drawing too much attention to things like pretty patterns. Which may have meaning. But it seems they're happy to see pretty patterns.

This is the worst one. This is science. Why are they using woo in science? "Observation interferes". Observation isn't woo. They're just not bright enough to see. Go and make a suitable detector would be more logical.

Why don't they show more slits?

Apart from 1 slit. Which is misleading. Why not show 3 or any other odd number to show you can have position of the wave propagation point?

Why use a 3d shape of a wave against 2d surface of a part experiment that is still in the box?

Go back to Feynman. He's easier to understand.

originally posted by: blackcrowe
That drain has at least 2 big pipes running length ways along the road attached to it. The pipework is bedded on a stone bed. Then, surrounded by stone.

I GUESS the whole length of pipework was lifted as the stone surrounding worked it's way underneath. Lifting the inspection chamber with it.

If you take a long pipe like that and fill it with air (maybe it's already full of air) and try to submerge it in a lake or something, what would happen? The concrete is more dense than water, so that would tend to sink, but the air is less dense, so that would tend to float. So whether the pipe sinks or floats depends on the concrete to air ratio and whether the entire thing is more or less dense than what it's floating it, water, in the case of the lake.

There is probably some kind of flotation effect going on with the pipe during an earthquake but there are so many variables it's a rather complicated thing to study, especially since it's not easy to make an earthquake in a lab. Some researchers tried to make a simulated earthquake by putting shaking tables on centrifuge platforms to study this, though I'm not sure why they needed the centrifuge and couldn't just use the shaking tables. The centrifuge provides higher g-forces but I would have thought they could duplicate it at 1g plus the shaking. Anyway they interestingly found the pipe in their test kept floating up a little bit, even after the shaking stopped (at about 31s in the graph below):

Uplifting Behavior of Shallow Buried Pipe in Liquefiable Soil by Dynamic Centrifuge Test

Underground pipelines are widely applied in the so-called lifeline engineerings. It shows according to seismic surveys that the damage from soil liquefaction to underground pipelines was the most serious, whose failures were mainly in the form of pipeline uplifting. In the present study, dynamic centrifuge model tests were conducted to study the uplifting behaviors of shallow-buried pipeline subjected to seismic vibration in liquefied sites. The uplifting mechanism was discussed through the responses of the pore water pressure and earth pressure around the pipeline. Additionally, the analysis of force, which the pipeline was subjected to before and during vibration, was introduced and proved to be reasonable by the comparison of the measured and the calculated results. The uplifting behavior of pipe is the combination effects of multiple forces, and is highly dependent on the excess pore pressure.

a reply to: blackcrowe
As I said I didn't list this for Daniel because it's a rather complicated experiment and he is asking very simple questions, so I'm not trying to say this experiment is easy to understand. If Feynman explained it he might do a better job, but unfortunately he died over a decade before this experiment was performed in 1999.

The reason two slits are used is because they most easily demonstrate the properties of wave-particle duality in the two slit experiment which is easier to understand. Three slits doesn't really add anything to our knowledge that I can think of over using two slits.

I don't understand what specific reference you object to in the video, maybe give me a time index to look at and I'll try to clarify if I can.

What Richard Feynman did say, after winning a Nobel prize for his theory related to quantum mechanics, is "No one understands quantum mechanics", although Maybe it should have said "No one except Delbert Larson understands quantum mechanics"?

What he meant by that is that quantum mechanics can't be understood using our experience with the ordinary classical world, the point I tried to make to Daniel when he keeps trying to interpret things classically.

a reply to: Arbitrageur

It happens.

It caused damage to earth structures and residential houses, as well as the uplift of manholes.

www.sciencedirect.com...

a reply to: Arbitrageur

If you take a long pipe like that and fill it with air (maybe it's already full of air) and try to submerge it in a lake or something, what would happen?

Does your dad know your messing around on his computer while he's out?

Why don't you try it?

But. you wouldn't need to try to submerse it.

Three slits doesn't really add anything to our knowledge that I can think of over using two slits.

I disagree. They've learned only how to confuse themselves by not pushing the experiment on.

a reply to: blackcrowe
I showed you the experimental results where a smaller pipe floated up a little in the lab, even after the shaking stopped, so I don't really understand your comment.

What do you think adding a third slit to the double slit experiment would add? We have models to predict what would happen and like many other tests of quantum mechanics where experiments have resulted in what was predicted, I don't see any reason to expect otherwise here.

Rather than adding a third slit, physicists thought the delayed choice quantum eraser experiment was a better way to push the two slit experiment on as you put it, to add to our knowledge, since it does tell us more than the simpler two slit experiment.

a reply to: Arbitrageur

A 3 slit experiment would show you something different.

Labelled 1,2 and 3. With detectors with corresponding numbers.

The results would seem strange.

The first particle would appear from 2 detector. followed by 1 and 3 as a pair.

An odd number allows you to find position.

In this 3 slit case. Position of waveform would be in front of number 2.

Up it to 9.

Position in front of number 5.

Firing sequence. 5 first. Then 4 and 6 in a pair. Next 3 and 7 pair, 2 and 8 pair and last 1 and 9 pair.

Seems strange to see a single particle followed by pairs. Why?

3d wave shape on a 2d surface.

Try curving the wall.

If the curve is right.

Firing sequence of 9 slit experiment. All 9 particles show at the same time.

Also. With odd numbers. You can plot on a grid by squaring ant odd number.

a reply to: Arbitrageur

Excellent. I have an hour commute to work, and an hour and a half back, each work day. In the last week I turned on the radio. For the past year plus I would think about the latest aether puzzle, but I am at the point on the aether were I think I've got it all now. I am writing it up, and sometimes during the full math derivation things break down, so I'm not done yet, but I often don't need to think about it anymore. I just need to find time to write. So I turned on the radio.

Now I have something to think about. I hadn't heard about the quantum eraser experiments. I left Fermilab around 1998, and when not making a living and raising kids I've concentrated on older problems.

I've thought about the quantum eraser overnight and still don't understand it. I've made some progress in my understanding, but this one is taking some time. I am just writing to let you know I will think about it and get back when I have something of value to say.

Thanks for the new puzzle!

The radio will be back off.

a reply to: Arbitrageur

You know that supersymmetry .

One hundred billion and 1 slits.

Position the wave point in front of the centre slit and fire a wave.

The result is.

One particle shows first. The central one.

Followed by pairs.

But. I have no right to make such claims.

It can't be true anyway.

Nobody is offering to pay me to shut up.

a reply to: blackcrowe

The 3 slit experiment would just show different patterns the results would be the same. According to the superposition principle, any two quantum states can always be added together to create a third, valid state.

You just make it more difficult to determine probabilities with more slits. With superposition the wave function describing the beam passing through all three slits will be equal to the sum of the wave functions associated with each individual slit. Meaning nothing is gained other than being more difficult to see a pattern.

originally posted by: blackcrowe
One particle shows first. The central one.

Followed by pairs.

I don't really understand what that means. To understand why, consider this: One interesting way of performing the double slit experiment is sending through one particle at a time. so if you just send one particle there is no sequence like "first" or "followed by" with one particle, it's just one particle.

So scratch the "first" and "followed by" and think about what a single particle would do when it passes through the three slits, and as dragonridr says even that is not hard to predict, in fact the interference equations are shown below, where you will find the constructive and destructive interference.

originally posted by: dragonridr
You just make it more difficult to determine probabilities with more slits. With superposition the wave function describing the beam passing through all three slits will be equal to the sum of the wave functions associated with each individual slit. Meaning nothing is gained other than being more difficult to see a pattern.

Exactly! But this is so well understood that anybody can download a java applet that will use the known math to simulate the interference pattern with any number of slits from 2-20 and if that's not enough you could write your own applet to do more. With this app you can also vary other things like the slit width, the slit spacing, and the frequency of the light. I made a screenshot of the applet mathematics, the applet itself, and the description from the download page. The N=2 in the upper left is for two slits, just change it to 3 if you want to see what will happen with three slits, or any amount of slits up to 20.

www.cabrillo.edu...


a reply to: delbertlarson
Sure, take some time to think about it!

One thing I'd like to point out to you in the video is how the speaker seems rather open-minded to various possibilities. I'm not sure if he prefers one interpretation of quantum mechanics, but he discusses whether the wave function might be physical as in the DeBroglie Bohm interpretation or whether it might not be physical as in the Copenhagen interpretation, and what the implications are for whether the collapse of the wave function could be instantaneous or not. If he's allowing relativity to limit his thinking in some way as you have suggested relativity seems to do with mainstream physicists, it's not apparent to me, since he discusses both possibilities, whether the collapse is instantaneous or not.

a reply to: Arbitrageur

So scratch the "first" and "followed by" and think about what a single particle would do when it passes through the three slits, and as dragonridr says even that is not hard to predict, in fact the interference equations are shown below, where you will find the constructive and destructive interference.

A 3 slit experiment would show you something different. Labelled 1,2 and 3. With detectors with corresponding numbers. The results would seem strange. The first particle would appear from number 2 detector. followed by 1 and 3 at the same time as a pair. An odd number allows you to find position.

The wave is a curve. Radiating out from a position in front of slit 2. With slits 1 and 3 each side of 2.

A curve radiates out from point 2. The curve can't hit all 3 slits at the same time. It's a curve. The wall is flat.

With an odd number of slits. The curve particle can only go through slit 2.

Slits 1 and 3 will be hit with the curve and show particles next. The slits order is a dependant of the shape of a curve.

Sorry it took me so long to catch up delbertlarson.

a reply to: blackcrowe
It seems you ignored my suggestion:

originally posted by: Arbitrageur
So scratch the "first" and "followed by" and think about what a single particle would do when it passes through the three slits

Did you think about that? I can't see that you did.

You said you watched the quantum eraser video, which explained why a coherent light source was used for the double slit experiment, which is typically going to be a laser as seen in this video:



I don't think "The wave is a curve" is a very good description of what happens with that apparatus. If you insist that it is, how do you calculate the radius of the curve? The light beams from the laser may not be perfectly parallel, but are pretty close because the are collimated by bouncing the light between two parallel mirrors to make them as parallel as possible.

I don't understand your obsession with the three slits because even if you can set something up as you describe where you actually can calculate a radius of a curved wave front, the results will be quite predictable and won't tell us anything we don't already know. What you might see is something similar to what you might see in the java applet if you adjusted the distance between the three slits a bit. That's more or less just geometry, and we understand geometry pretty well, a lot better than we understand quantum mechanics, and the main reason the double slit experiment is interesting is because it helps demonstrate things we don't understand very well, like the central mystery of quantum mechanics.

Why do Polar explorers come across HOT winds and birds migrating NORTH at the pole

a reply to: stonerwilliam
To answer, I would need links to what you're talking about. What polar explorers specifically? How hot is "hot"? What temperatures did they measure and where and when did they measure them? Etc.

Birds can't migrate north at the north pole. If they are at the north pole, every direction is south. Except maybe up or down which won't get them very far.

a reply to: Arbitrageur

William Reed the phantom of the poles 1906 , Admiral bird expeditions ! and a explorer called Nansen who above the 81st parallel talked of a incredible heat even in Dec

originally posted by: stonerwilliam
a reply to: Arbitrageur

William Reed the phantom of the poles 1906 , Admiral bird expeditions ! and a explorer called Nansen who above the 81st parallel talked of a incredible heat even in Dec

In summer you'll get up to 10°C in the Arctic.

81st parallel is over 600 miles away from the pole.

Please provide actual citation for the "incredible heat even in Dec" claim.

a reply to: Arbitrageur

They sell inexpensive polarized strips for cell phones on Ebay.
Similar experiment can be done with those.
Also there are the little plastic PC dust guards with the round hole patterns that make varying size hexagons when you change the angle between two layers.
Good for 7 year olds learning physics.

a reply to: Arbitrageur

I don't think "The wave is a curve" is a very good description of what happens with that apparatus. If you insist that it is, how do you calculate the radius of the curve?

Ah. I get it.

A wave radiating outward in all directions has no curve. Makes sense.

The patterns which keep getting mentioned are confusing. Because it's an even number. Antimatter.

Odd numbers are matter.

There are lots of patterns. I don't know what they mean. I don't understand them. But to keep paying attention to them is foolish at the moment. They do mean something. I just can't work it out.

originally posted by: blackcrowe
A wave radiating outward in all directions has no curve. Makes sense.

A water wave radiating outward in all directions does have a curve, so it doesn't make sense to say that has no curve. But we weren't talking about water waves, we are talking about the double slit experiment, and the objects used in the double slit experiment such as a single photon, a single electron, a single atom, a single molecule do not radiate outward in all directions. None of them do that. If you aim the laser at the double slit, that's the direction the photon travels, toward the double slit. The single photon does not radiate outward in all directions, and even if you count multiple photons, using the typical laser apparatus, they are collimated so again not radiating outward in all directions.

If you aim the electron beam at the double slit, that's the direction the electron travels, toward the double slit. It's not radiating outward in all directions.

Same with atoms and molecules. The double slit experiment has been done with a buckyball. If you aim the buckyball toward the double slit, that's where it goes, it's not "radiating outward in all directions".

If you add a third slit to the double slit experiment, that doesn't make any of those things suddenly start "radiating in all directions", that's not the way particles behave, and they are all particles or at least exhibit particle-like behavior in traveling in the direction of the double slit, rather than spreading out isotropically.

Whether it continues to exhibit particle like behavior or not as it passes though the slits depends on whether you measure which-path information. If you do, it continues to behave like a particle, and passes through one slit or the other (or neither), and doesn't behave like a wave in that case, they behave sort of like marbles, and marbles also do not radiate outward in all directions, it's somewhat like a large particle, though I don't expect to see it used in the double slit experiment anytime soon. We might be able to perform a double slit experiment with something larger than a buckyball, though I'm not sure how large of a particle will eventually be used except to say it's definitely not practical with a bowling ball.

originally posted by: stonerwilliam
a reply to: Arbitrageur

William Reed the phantom of the poles 1906 , Admiral bird expeditions ! and a explorer called Nansen who above the 81st parallel talked of a incredible heat even in Dec

I asked for links and got no links, so I ran a search on Nansen. Found this picture of his boat frozen in the ice.

sciencenordic.com...


It doesn't look hot to me. I read several articles about him, one said scientists today still review his temperature data but the article made no remarks about the temperatures being "Hot". I mean if the normal temperatures are minus 40C, then maybe 0 C seems "hot" in comparison but I don't consider that particularly hot, if we are talking surface temperatures.

If we are talking about temperatures underwater, then there are some warm temperatures in the arctic ocean due to underwater volcanoes, but without any references, I have no idea if that's what you're talking about. Here are some articles about the underwater volcanoes:

Volcanoes Erupt Beneath Arctic Ice

"We don't believe the volcanoes had much effect on the overlying ice," Reeves-Sohn told LiveScience, "but they seem to have had a major impact on the overlying water column."

Underwater Volcanoes Heating the Arctic Ocean

The Arctic Ocean is heating from below, a new study has found.

One thing I noticed about volcanoes, is the active ones do seem to get hot, and apparently there are quite a few underwater in the arctic ocean.

a reply to: Arbitrageur

Thanks.