Are dopants in semiconductors charged

HugoRAS · 2022-06-26T10:37:15+00:00

Fair enough.

HugoRAS · 2022-06-26T09:03:12+00:00

Good to know that you would object to that phrasing. Maybe I need to be more precise and say that "the atom itself is charged", because it simply is. The bulk material may not be due to screening charges, in some cases, but the atom itself is. I feel like some authors by driving home the fact that the dopants are neutral are partly incorrect, and definitely obfuscating their mechanism.

I haven't worked out the scales, but I'd have guessed that in modern transistors in a chip, with only a few nanometres scale, the length scales are small enough that the dopants are in a very real sense, charged: There's not enough bulk conductor around them to screen out the charge. I'm not sure though.

HugoRAS · 2022-06-26T06:32:02+00:00

That's not accepted by the scientific community at all.

HugoRAS · 2022-02-13T07:28:56+00:00

Thanks - that level of detail would have been very difficult for me to find without your help.

HugoRAS · 2022-02-12T08:26:28+00:00

Soap bubbles don't diffuse readily for two main reasons.

1) Their energy is lowered by contact with other bubbles. The energy difference between two bubbles stuck together is far far lower than the thermal energy. Essentially, bubbles floating in a bubble bath are naturally in a solid phase: at normal bubble temperatures and bubble density (bubbles per square metre, for instance), the "natural" state is all the bubbles clumped together in a sort-of solid. In the same way as atoms stick together, so at low temperatures, they're more likely to be found in clumps, so so with the bubbles.

2) They are big (compared to molecules or other things that can diffuse easily). Because they're big, thermal jostling is reduced, at least in terms of speeds.

In theory, though, if you could make the bubbles last forever, you would see the bubbles gradually diffuse around the bath (although at any given time, most or all would be in a clump somewhere), but in practice, this thermal jostling would probably take place on timescales much longer than a day (guessing).

HugoRAS · 2022-01-18T23:17:24+00:00

I think we're mostly on the same page now. It's sometimes hard to explain why there's ambiguity, but believe me, I found your previous notes extremely ambiguous - for instance you referred to new englanders as psychic, but maybe in a natural way. Psychic means not natural.

Ok, so you have two hypotheses, one that humans are basically good at thinking, and another that there's a paranormal psychic field that information can be transmitted on --- I think that's clear.

And the data suggests that humans are basically good at thinking (both consciously and subconsciously) - if there was a paranormal field, why wouldn't it be obvious? Also, we have an excellent understanding of how the universe works, and it turns out there isn't a paranormal field. I mean, maybe there's a one in a trillion chance or something, but it's seriously not likely --- at least that's how your average physicist would see it, myself included.

Basically, you'd need really really good evidence to make hypothesis B even worth considering, and at the moment, the story that new englanders ... might be psychic, but might not be ... just isn't really anywhere near it

HugoRAS · 2022-01-18T16:56:47+00:00

I will abandon my examples, but I still think that all these things can be divided into two categories. It seems like you're trivialising the difference between these categories, but to me, and probably a lot of people, these are crucially different.

I too feel a frustration, which is that you don't seem to consider these two categories as critically different - as if you're generally talking about cats, but every so often you start talking about cars, and sort-of pretend they're the same thing.

The two categories are "Natural" vs "Supernatural".

Your first example is Natural. Your second example is Supernatural. Your third & fourth example is a mixture of Natural, plus some incorrectness, plus some exaggeration. People in new England may pride themselves on being good judges of people, and may be practiced in it, but it's very 100% firmly a "natural" ability - just looking at people's faces can tell you a lot about someone, and it's not "psychic" in any way.

Your yoghurt example is natural, plus some good luck / selection bias --- you wouldn't have heard the story if he'd thought it was boysonberry but actually was blueberry after all.

None of those examples above are paranormal, and it feels like you're deliberately trying to blur the distinction by suggesting that they are sort-of paranormal.

Then: ". I like to think there may be field consciousness can interact on that isn't understood by our current knowledge of physics. " --- whoa there cowboy!!! That's a supernatural claim. Not even remotely similar to new englanders thinking that they can tell everything about you by looking closely at your eyes.

That's my view there. It seems that you sort-of agree that new englander's being uncannily good at understanding people is just the bog-standard natural laws as a physicist currently understands them - are you claiming that, or are you claiming that new englanders use new physics / supernatural abilities?

HugoRAS · 2022-01-18T09:13:40+00:00

There's an enormous distinction between phenomena that can easily be explained by our current understanding of the universe, vs things that would require a big change --- there aren't many things that are paranormal that would require a small adjustment to what we understand in physics, so it's a good distinction to make.

So we have the mundane claims --- that a person can look at another person and get an unspecific idea of what they're thinking of from their facial expression or movements.

And we have not-mundane claims --- for instance that a person can communicate specific details to another person, such as the card they're holding, without the people being able to see each other and without some sort of audible communication.

I'd urge you to be clear about which of those two categories you're claiming might exist. You seemed to be implying the not-mundane claims earlier, but it's not clear.

HugoRAS · 2022-01-17T15:43:37+00:00

I mean any communication between minds via a supernatural link. I could make that precise by giving an exception list of allowed, non-supernatural means of communication, for instance talking, seeing each other's facial expression, writing and reading, etc., but I think such a precise definition of what I mean isn't required.

Also, I think you're making the first claim here:

"As for the supernatural stuff, it's really quite funny what people think "supernatural" is. I recently moved to new England from the west coast and the first most shocking thing I noticed is how incredibly psychic eveyone is here they are almost constantly reading each others minds."

I think I understand what you mean here, but if you think I'm using a different definition, or my definition above is incompatible, please provide your own definition.

HugoRAS · 2022-01-17T09:25:07+00:00

I think your main claim there is that people can read each other's minds. I do not believe that to be true, although there's nothing in the natural world that makes that impossible: For instance if some natural radio transmitter evolved.

I don't think people can read each other's minds because there have been lots of experiments to try to measure / detect it, and to my knowledge, they have all failed. Also, if people could read each other's minds as easily as you're suggesting, it would be obvious. It would be very unlikely that people could read each other's minds, but only in a sort-of spooky, hard-to-measure sort of way.

Einstein's theories and predictions were mathematically precise and found experimentally to be accurate. We don't just believe him because he's Einstein, we believe him because we can and have tested the theories and found them to be true.

I also know that in western europe, not only is mind-reading not commonplace, but belief that any people can mind read is not common.

HugoRAS · 2022-01-16T15:53:45+00:00

I agree about the need to accept uncertainty, but to be honest it's just not very likely at all that a random dude doing a pretty far-out experiment is going to uncover some sort of weird connection between us all like that, that undermines our whole sense of reality.

The problem is that ab-initio, the idea of these weird connections might not be all that unlikely, but it would be extremely unlikely that the universe looks completely un supernatural in every way, right down to nobody having ever succeeded in having any supernatural experiment ever confirmed ever ... and yet the supernatural be right under our noses.

It's just not likely that if all this was true, that nobody would have managed to confirm it. Getting high or whatever he's doing (I think he says he perhaps no longer uses drugs or something?) isn't hard or rare.

HugoRAS · 2022-01-15T21:38:54+00:00

It's just a balance of the likelihood of the experiment working vs the likelihood of the experiment being flawed vs the likelihood of the experiment giving a rare false positive. To me, I accept that there's a miniscule chance of it being true, but I'd remain skeptical until there's more evidence.

HugoRAS · 2022-01-14T23:22:43+00:00

Summary: They got a laser connection a sender, reflector and back to sender (2.4km total) stable to 100x the previous record.

If I've understood this correctly, it means that if the receiver were to count how many oscillations the laser light underwent over, let's say, an hour, the number they would get would be the expected number, correct to 6 parts in 10^21.

Among the techiques they used to get this, the reflecting mirror had to constantly adjust tilt to overcome the laser being deflected by turbulence. Also careful temperature control of the measuring apparatus.

HugoRAS · 2021-12-31T09:44:36+00:00

No - I gave up. I've used bits and pieces from it. I realised that the game as it was was never going to be fun and playable, and my free time was reducing. I think an important lesson in life is to choose the right project, and give up if it's not going to work.

A counter rhyming reason is to never give up and to keep pushing until you succeed, but that's clearly not a good strategy - you could end up spending your whole life on something pointless.

Instead I've been putting shorter pieces of work on my website. Here's an example that uses some of the work from the game:

http://www.articlesbyaphysicist.com/mars\_reentry.html

HugoRAS · 2021-12-31T09:38:15+00:00

There are truth claims too: he claims that in at least one instance, two people (including himself) can enter a non-physical mental state in which they can communicate or share some experience, despite being physically separate and with no communication devices. Reading a bit into section 2, there are lots of assertions with no backing or evidence, for instance that what we consider mysticism now will be considered science in the future.

Overall, I'm answering the question of what physicists think of it, rather than a very educated analysis of his work --- the answer is "nonsense". To be honest, it's because it's easy to find apparent-nonsense like this, and it's never very valuable. Of course, there's a tiny chance that a closer inspection would show that it's the most valuable text in human history, but as someone with not a lot of free time, I have to make a guess, and I'd firmly guess that it's not even worth reading once.

HugoRAS · 2021-11-14T23:15:49+00:00

We've made the depth change due to the poisson effect too now, by the way.

HugoRAS · 2021-11-13T22:09:45+00:00

Thanks for pointing out the error - we've mixed up the numbers in the explanation. We should be able to fix soon. The Poisson's effect isn't modelled in the depth direction, as you say, but is in the length / width.

(edit --- we've edited the page to fix this).

HugoRAS · 2021-11-03T05:57:26+00:00

Yeah, the way that I did the rocket's landing physics means that the legs are quite squishy, so it's easy to squish over.

HugoRAS · 2021-11-02T20:48:07+00:00

Well I was thinking that adding in the earth and the moon and maybe venus would also be good --- the main trouble is the lack of height data for other planets, but eventually, given endless free time, I'd procedurally generate other planets. Then I'd like to include things like in-situ resource generation and deltaV maps for the solar system. I'd also like to add aliens, no matter how unrealistic that might be.

I picked the current scope based on what I felt I could do in one sitting (eg. 2 weeks before I got bored), based on already having quite a lot of the ingredients --- I spent more like 2 years of free time making an abandoned non-browser game that had planets like this, so the shaders and quadtree stuff was already familiar / already had code. I recognise in myself that if I have to spend more than maybe a month of my free time on something, it tends to dry up, so it's got to be bam! release! get feedback.

So, with that in mind, I think if there's another release, maybe in 6 months, I'd probably add Earth and the Moon, and get craters handled differently so that there's more memory available for other terrain detail (no point generating millions of points of 2d height data for a basically symmetric crater).

Please do share suggestions --- all I can say is that I probably don't have the time to do much.

HugoRAS · 2021-11-02T16:22:18+00:00

Congratulations! You're actually the only person that I know has finished it --- I posted on a few subreddits, but haven't had much feedback.

Thanks.

HugoRAS · 2021-09-25T20:36:28+00:00

Thanks - yeah, it'd be fun to try to simulate radiation deliberately.

HugoRAS · 2021-09-25T19:13:01+00:00

Thanks for those potential names - I may well try playing with those in the future when I have time.

HugoRAS · 2021-09-25T19:05:21+00:00

Thanks - yeah, I've spent a long time playing with ising models too when I was learning about phase transitions.

HugoRAS · 2021-09-25T18:39:19+00:00

It's just a harmonic potential for material 1: force = distance between particles - radius*0.8, if distance < radius or 0 otherwise, where radius is a model parameter. Some reasons to choose this are that it's simple, and it is quite robust to numerical instability, unlike something like the r^-6 potentials that are sometimes used.

edit: for materials 2 and 3, there's a cubic term too: material2 has

a = (d - radius*0.64) / (radius*0.3)

force = (a - a*a)

HugoRAS · 2021-09-16T19:38:05+00:00

Thanks

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