7 ms·

The first atomic bomb created ‘forbidden’ quasicrystal

104 points by danboarder 5y ago

namelosw 5y ago
I just happened to come across this fascinating video[0] yesterday that explained the same thing. And he mentioned the crystal as well. [0] The Infinite Pattern That Never Repeats: https://youtu.be/48sCx-wBs34 https://youtu.be/48sCx-wBs34
- belter 5y ago
  Great video thanks for sharing. My brain still hurting, it tried to explode at 14.38 :-) https://youtu.be/48sCx-wBs34?t=878 https://youtu.be/48sCx-wBs34?t=878 Also quite interesting these are found in a few meteorites. I wonder if somebody is confidentially keeping some quasicrystal with very special properties somewhere. "Third-ever natural quasicrystal found in Siberian meteorite" https://www.newscientist.com/article/2115570-third-ever-natural-quasicrystal-found-in-siberian-meteorite/ https://www.newscientist.com/article/2115570-third-ever-natu...
  - belter 5y ago
    It seems many here did not like the fact I did not know and find completely obvious, the fact that a Fibonacci sequence is a fundamental example of a 1D quasiperiodic structure exhibiting aperiodic long range order :-))
throwawaysea 5y ago
The article concludes by suggesting that people will create more quasicrystals in labs, with various desired properties. That seems reasonable. What I didn’t understand is this line: > And the more mathematically perfect they are, the less electrically conductive. Anyone understand what “mathematically perfect” means here, or why that implies reduced conductivity?
- mastazi 5y ago
  I'm not sure if my guess is right but my understanding is that "mathematically perfect" is related to how close to actual crystals they are. For example the Penrose tiling in the picture is made of tiles of 2 different types, so it's more "perfect" than another pattern that would use 3 different types of tiles, etc.
- nleconte 5y ago
  I would have imagined it is used in the same way it is used for crystals. Mono-crystals are considered mathematically perfect, while poly-crystals (with their grain-boundaries separating different cyrstal orientations) are less perfect. So, for quasi-crystal, the patterning which follows a set of mathematical rules (although lacking translational invariance), can be interrupted, thus being "mathematically less perfect". Now as to why that implied reduced conductivity... thinking in terms of Bloch waves, they require periodicity. In absence of Bloch waves that describe the electron density probability, the electrons are considered to be localized (e.g. as in the Landau level description of electrons implying localization of electrons in a perfect crystal). So for perfect quasi-crystals, this periodicity is fully absent, thus they are localized too. The latter hand-wavy argument is just speculation of mine...
mastazi 5y ago
Wow this seems to be a very exciting research field: > Although more than 100 types of quasicrystals have been discovered since 1984, Steinhardt says that an infinite number of possibilities may exist — each with their own elastic, electronic, and photonic properties tied to the periodic ordering of their atoms. > Steinhardt’s own research group has worked to create “photonic quasicrystals,” which act as semiconductors for light and form nearly perfect spherical symmetric band gaps. That feature is desirable in circuit designs and could be used in future computer and communication devices.
- senectus1 5y ago
  I would imagine that once you start blowing stuff up in zero G you'll get even more interesting results. ie: https://en.wikipedia.org/wiki/Widmanst%C3%A4tten_pattern https://en.wikipedia.org/wiki/Widmanst%C3%A4tten_pattern
- nleconte 5y ago
  A recent playfield for quasi-crystals have bee realized by making 30 degree twisted bilayer graphene. This playfield has been extended as well using stackings of any 2 different moire systems into one, with a 30 degree misalignmnent between the respective moire angles.
  - bedobi 5y ago
    Are you sure? My understanding was that perturbations resulting from subatomic crevasses in multi-dimensional lattices would render the impedance greater than the Yui-Schwarz limit.
    - nleconte 5y ago
      https://pubs.acs.org/doi/10.1021/acs.nanolett.0c00172 https://pubs.acs.org/doi/10.1021/acs.nanolett.0c00172 This was not the first work on this, but it's the first that shows with a quick Google search while in the subway. Let me take some time to understand your comment. In the meanwhile, the whole field of superlaticces got a great boost with the first realization of moire systems using hBN, graphene and the like in 2013(?) by P. Kim and others. Before that, indeed, patterning superlattices from the bottom-up had been a laborious and mostly failing endeavor. If that's what you are referring too...
l33tman 5y ago
As a complete tangent, I recently heard a podcast [1] with Frank Wilczek, inventor of so called time-crystals, where he discussed materials where waves can propagate according to a rich enough set of rules to essentially "simulate" another world with its own set of physics. Fascinating. [1]: https://youtu.be/0zAlEjFU7xo?t=3000 https://youtu.be/0zAlEjFU7xo?t=3000
eequah9L 5y ago
> quasicrystal materialized in temperatures above 2700 degrees Fahrenheit and pressures of 5000 to 8000 pascals. To you and me, it would feel similar to [...] someone carrying thousands of elephants [...] stands on your back. Hmm, from my mechanical engineering times, 8 kP does not sound like a big deal at all. Say it's 5 tons per elephant, which would be about 50kN. A human foot is about 25 cm long, and I guess two of them might be about as wide, so 0.0625 m^2. Pressure is force over area, so 800 kN/m^2, or 800 kP. That's per elephant. I'm going to assume the article is missing a "mega" somewhere in there.
- contravariant 5y ago
  Given that atmospheric pressure is around 100,000 pascals, yeah they're probably missing some SI prefix. Edit: The original article talks about pressures of 5 to 8 GPa. [1] [1]: https://paulsteinhardt.org/wp-content/uploads/2021/05/BindiEtalTrinitite.pdf https://paulsteinhardt.org/wp-content/uploads/2021/05/BindiE...
- hexo 5y ago
  Reading those Fahrenheits and pascals in one sentence really hurts.
  - richrichardsson 5y ago
    For anyone not in USA (or the tiny handful of other countries still using it), Fahrenheit hurts to read full stop.
    - dboreham 5y ago
      Not if you're a human describing their environment: zero is F.cold and 100 is about as hot as you can stand.
      - mabbo 5y ago
        What if some humans have different temperature preferences? Do they get a different temperature scale to suit them?
ralabaster 5y ago
Oh, so now they’re ‘forbidden’? A few months ago they were only ‘impossible’.[1] I saved the article (which also was here on HN) at the time because it contains the conceit “science does what puny humans say is impossible,” but the people who say things are impossible are scientists themselves. Are we supposed to be impressed by that? Plagiarists, AKA journalists, get paid to copy other people’s work. Come to think of it, that’s what Stack Exchange is for, too… [1]https://www.nature.com/articles/d41586-021-01332-0 https://www.nature.com/articles/d41586-021-01332-0
- craftinator 5y ago
  Much like the Colonel's 11 Secret Herbs and Spices, they are both Forbidden to know, and Impossible to understand.
egberts 5y ago
What would be most interesting about these quasicrystal characteristics are: 1. tensile strength 2. cleaving strength 3. torsional strength We have got starships to make that need to handle these upcoming warp engines. Just looking ahead here.
- Nbox9 5y ago
  I am not a physicists. I wonder if those properties would not be uniform across the quasicrystal because of it’s non-repeating pattern.
woah 5y ago
> To you and me, it would feel similar to lying inside a volcano while someone carrying thousands of elephants (presumably stacked vertically) stands on your back. Finally, a journalist using units of measurement I can relate to.

104 points by danboarder 5y ago

I just happened to come across this fascinating video[0] yesterday that explained the same thing. And he mentioned the crystal as well. [0] The Infinite Pattern That Never Repeats: https://youtu.be/48sCx-wBs34 https://youtu.be/48sCx-wBs34

belter 5y ago
Great video thanks for sharing. My brain still hurting, it tried to explode at 14.38 :-) https://youtu.be/48sCx-wBs34?t=878 https://youtu.be/48sCx-wBs34?t=878 Also quite interesting these are found in a few meteorites. I wonder if somebody is confidentially keeping some quasicrystal with very special properties somewhere. "Third-ever natural quasicrystal found in Siberian meteorite" https://www.newscientist.com/article/2115570-third-ever-natural-quasicrystal-found-in-siberian-meteorite/ https://www.newscientist.com/article/2115570-third-ever-natu...
- belter 5y ago
  It seems many here did not like the fact I did not know and find completely obvious, the fact that a Fibonacci sequence is a fundamental example of a 1D quasiperiodic structure exhibiting aperiodic long range order :-))

throwawaysea 5y ago

The article concludes by suggesting that people will create more quasicrystals in labs, with various desired properties. That seems reasonable. What I didn’t understand is this line: > And the more mathematically perfect they are, the less electrically conductive. Anyone understand what “mathematically perfect” means here, or why that implies reduced conductivity?

mastazi 5y ago
I'm not sure if my guess is right but my understanding is that "mathematically perfect" is related to how close to actual crystals they are. For example the Penrose tiling in the picture is made of tiles of 2 different types, so it's more "perfect" than another pattern that would use 3 different types of tiles, etc.
nleconte 5y ago
I would have imagined it is used in the same way it is used for crystals. Mono-crystals are considered mathematically perfect, while poly-crystals (with their grain-boundaries separating different cyrstal orientations) are less perfect. So, for quasi-crystal, the patterning which follows a set of mathematical rules (although lacking translational invariance), can be interrupted, thus being "mathematically less perfect". Now as to why that implied reduced conductivity... thinking in terms of Bloch waves, they require periodicity. In absence of Bloch waves that describe the electron density probability, the electrons are considered to be localized (e.g. as in the Landau level description of electrons implying localization of electrons in a perfect crystal). So for perfect quasi-crystals, this periodicity is fully absent, thus they are localized too. The latter hand-wavy argument is just speculation of mine...

mastazi 5y ago

Wow this seems to be a very exciting research field: > Although more than 100 types of quasicrystals have been discovered since 1984, Steinhardt says that an infinite number of possibilities may exist — each with their own elastic, electronic, and photonic properties tied to the periodic ordering of their atoms. > Steinhardt’s own research group has worked to create “photonic quasicrystals,” which act as semiconductors for light and form nearly perfect spherical symmetric band gaps. That feature is desirable in circuit designs and could be used in future computer and communication devices.

senectus1 5y ago
I would imagine that once you start blowing stuff up in zero G you'll get even more interesting results. ie: https://en.wikipedia.org/wiki/Widmanst%C3%A4tten_pattern https://en.wikipedia.org/wiki/Widmanst%C3%A4tten_pattern
nleconte 5y ago
A recent playfield for quasi-crystals have bee realized by making 30 degree twisted bilayer graphene. This playfield has been extended as well using stackings of any 2 different moire systems into one, with a 30 degree misalignmnent between the respective moire angles.
- bedobi 5y ago
  Are you sure? My understanding was that perturbations resulting from subatomic crevasses in multi-dimensional lattices would render the impedance greater than the Yui-Schwarz limit.
  - nleconte 5y ago
    https://pubs.acs.org/doi/10.1021/acs.nanolett.0c00172 https://pubs.acs.org/doi/10.1021/acs.nanolett.0c00172 This was not the first work on this, but it's the first that shows with a quick Google search while in the subway. Let me take some time to understand your comment. In the meanwhile, the whole field of superlaticces got a great boost with the first realization of moire systems using hBN, graphene and the like in 2013(?) by P. Kim and others. Before that, indeed, patterning superlattices from the bottom-up had been a laborious and mostly failing endeavor. If that's what you are referring too...

l33tman 5y ago

As a complete tangent, I recently heard a podcast [1] with Frank Wilczek, inventor of so called time-crystals, where he discussed materials where waves can propagate according to a rich enough set of rules to essentially "simulate" another world with its own set of physics. Fascinating. [1]: https://youtu.be/0zAlEjFU7xo?t=3000 https://youtu.be/0zAlEjFU7xo?t=3000

eequah9L 5y ago

> quasicrystal materialized in temperatures above 2700 degrees Fahrenheit and pressures of 5000 to 8000 pascals. To you and me, it would feel similar to [...] someone carrying thousands of elephants [...] stands on your back. Hmm, from my mechanical engineering times, 8 kP does not sound like a big deal at all. Say it's 5 tons per elephant, which would be about 50kN. A human foot is about 25 cm long, and I guess two of them might be about as wide, so 0.0625 m^2. Pressure is force over area, so 800 kN/m^2, or 800 kP. That's per elephant. I'm going to assume the article is missing a "mega" somewhere in there.

contravariant 5y ago
Given that atmospheric pressure is around 100,000 pascals, yeah they're probably missing some SI prefix. Edit: The original article talks about pressures of 5 to 8 GPa. [1] [1]: https://paulsteinhardt.org/wp-content/uploads/2021/05/BindiEtalTrinitite.pdf https://paulsteinhardt.org/wp-content/uploads/2021/05/BindiE...
hexo 5y ago
Reading those Fahrenheits and pascals in one sentence really hurts.
- richrichardsson 5y ago
  For anyone not in USA (or the tiny handful of other countries still using it), Fahrenheit hurts to read full stop.
  - dboreham 5y ago
    Not if you're a human describing their environment: zero is F.cold and 100 is about as hot as you can stand.
    - mabbo 5y ago
      What if some humans have different temperature preferences? Do they get a different temperature scale to suit them?

ralabaster 5y ago

Oh, so now they’re ‘forbidden’? A few months ago they were only ‘impossible’.[1] I saved the article (which also was here on HN) at the time because it contains the conceit “science does what puny humans say is impossible,” but the people who say things are impossible are scientists themselves. Are we supposed to be impressed by that? Plagiarists, AKA journalists, get paid to copy other people’s work. Come to think of it, that’s what Stack Exchange is for, too… [1]https://www.nature.com/articles/d41586-021-01332-0 https://www.nature.com/articles/d41586-021-01332-0

craftinator 5y ago
Much like the Colonel's 11 Secret Herbs and Spices, they are both Forbidden to know, and Impossible to understand.

egberts 5y ago

What would be most interesting about these quasicrystal characteristics are: 1. tensile strength 2. cleaving strength 3. torsional strength We have got starships to make that need to handle these upcoming warp engines. Just looking ahead here.

Nbox9 5y ago
I am not a physicists. I wonder if those properties would not be uniform across the quasicrystal because of it’s non-repeating pattern.

woah 5y ago

> To you and me, it would feel similar to lying inside a volcano while someone carrying thousands of elephants (presumably stacked vertically) stands on your back. Finally, a journalist using units of measurement I can relate to.