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Cake day: August 4th, 2023

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  • Codex@lemmy.worldtoScience Memes@mander.xyzAh yes, regression
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    26 days ago

    Going into physics was the biggest mistake of my life. I should’ve declared CS. I still wouldn’t have any women, but at least I’d be rolling in cash.

    Honestly, there wasn’t all that much cash to roll in and there’s less all the time now. Plus, if you think busted equipment is bad, wait until I tell you about inheriting legacy code.


  • A lot of things seem obvious until someone questions your assumptions. Are these closed forms on the Euclidean plane? Are we using Cartesian coordinates? Can I use the 3rd dimension? Can I use 27 dimensions? Can I (ab)use infinities? Is the embedded space well defined, and can I poke a hole in the embedded space?

    What if the parts don’t self-intersect, but they’re so close that when printed as physical parts the materials fuse so that for practical purposes they do intersect because this isn’t just an abstract problem but one with real-world tolerances and consequences?


  • The “=” symbol defines an equivalence relation. So “1+1=2” is one definition of “2”, defining it as equivalent to the addition of 2 identical unit values.

    2*1 also defines 2. As does any even quantity divided by half it’s value. 2 is also the successor to 1 (and predecessor to 3), if you base your system on counting (or anti-counting).

    The youtuber Vihart has a video that whimsically explores the idea that numbers and operations can be looked at in different ways.











  • Codex@lemmy.worldtoScience Memes@mander.xyzAssassin Bug
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    1 month ago

    Good definition! I’ll often say it is a “primary unit of cultural exchange.” I consider a lot of things memes: internet memes of course, songs, scenes from movies, plot tropes, characters, basically any bit of culture that can be encapsulated and identified as a distinct entity.




  • So photons, the particle of light, can interact with matter (atoms) in different ways. It could be absorbed by an electron, and then the energy transfered could knock the electron off the atom. That’s the photoelectric effect. It could also excite an electron into a higher orbital but not dislodge it, and often the electron will emit a new photon when it drops back down to ground state. That’s phosphorescence. The photon could also hit nothing and travel straight through.

    If you shot a photon (using a laser) through a cloud of atoms, you could watch for these interactions. Normally, light seems to slow down when passing through a medium (air or water) because the photons get absorbed and re-emitted. In bulk, this causes light scattering and slows travel.

    In this experiment, the cloud is made of ultracold rubidium. Rubidium is quite reactive and a pretty big atom, but i dont know specifically why it is used. What surprised the experimenters is that they could measure both the excited states of the atom and the emission of the photon. Sometimes, the atoms would seem to stay excited even though the photon had already been emitted, and also sometimes atoms would get excited even though no photon had been absorbed.

    This is interesting but kind of makes sense to me. The quantum properties of reality don’t disappear when we move up to bigger scales and aggregates. Rather the quantum properties seem to just “average out.” But this has weird effects. Electrons, for example, aren’t little balls in orbit around the nucleus. They’re waves of energy that get probabilistically smeared out over an “orbital”, an area around the nucleus where that electron is likely to be located. When atoms combine into molecules, the orbitals also combine into complex orbitals over the entire molecule. And when lots of atoms get arranged into a crystal (like in metals) those orbitals smear out over the entire aggregate. That’s kind of what it is to be entangled with other matter, to be bound up in the same quantum probability function.

    So to my mind, looking at how one atom reacts with a small number of atoms in a supercooled cloud doesn’t make sense, and gives weird results like negative time. The wave function of the photon must account for the wave function of the entire cloud. The single photon has infinitely many possible interactions through the cloud, which in aggregate always amount to taking longer to pass through while exciting some electrons along the way.