2025-10-30T09:18:34Z https://njump.me Vanessa https://njump.me/npub14wp4nlt3yrg3rwurudnmgkhvma4fmzqawmhkdqq30295ecz44qhqplmlcg https://media.mathstodon.xyz/accounts/avatars/110/796/413/859/804/364/original/a955c7f5779f4a1b.jpg https://media.mathstodon.xyz/accounts/avatars/110/796/413/859/804/364/original/a955c7f5779f4a1b.jpg https://njump.me/nevent1qqszmgvr6x56cujnsfnd033zdkqulu0pfjdenhpz2ledt20z2u7dgjszyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zu8k5l20 In reply to <a href='/nevent1qqsdk47p2recpgg0v84zfgd72dtuwpey9mdud7t7nacwm5sknpeuecsscftkf'>nevent1q…ftkf</a><br/>_________________________<br/><br/>can&#39;t really judge sadly because they kept rambling about string theory a lot and I&#39;m not particularly knowledgeable sadly.<br/><br/>For the Einstein part, around 40 to 50. I also feel like &#34;stating your Erdös number&#34; should be on that index because they did that too. 2025-01-22T17:30:15Z https://njump.me/nevent1qqs8ru0xspmw46f6m7sszklr5uzsl9dkvzugpx43v73wukaanfvj5pczyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zuyqtvsh just got my first crackpot mail from someone who wants to disprove Einstein. Guess I&#39;m a real physicist now 🥰 2025-01-21T14:08:28Z https://njump.me/nevent1qqsr8khm6en9j8axetk9kahgtyzmqd8a5m94jndlc8kfdlvphm4xhtqzyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zujwm9ld In reply to <a href='/nevent1qqstg9eak44vzga9e2md5tf4tzhvwywzku4a0d64g3nufhj9uq7m5eq3wzy8m'>nevent1q…zy8m</a><br/>_________________________<br/><br/>I just looked it up, and I seem to have misremembered: the GR-specific tensor diagrams are called &#34;Penrose graphical notation&#34; (<a href="https://en.wikipedia.org/wiki/Penrose_graphical_notation">https://en.wikipedia.org/wiki/Penrose_graphical_notation</a>) 2024-11-22T07:30:12Z https://njump.me/nevent1qqstl9tcejd77vxgs0fl42th8jf37wv6t0q2qf73cwrwxf6csxs820czyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zu57m253 In reply to <a href='/nevent1qqsrnlx6ae30vg93sudnggnqzwlalal3tdw6520qjrds8uxm924l60s8248dt'>nevent1q…48dt</a><br/>_________________________<br/><br/>also, on a side note: It just occurred to me that there is a namespace collision between Penrose (conformal) diagrams and Penrose (tensor network) diagrams... 2024-11-21T21:28:09Z https://njump.me/nevent1qqsrnlx6ae30vg93sudnggnqzwlalal3tdw6520qjrds8uxm924l60szyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zuah6ah7 In reply to <a href='/nevent1qqstxfhsetu4lmjlqrg7wg43lqyhjkz2lme2s943x6x25wkyrnusqnqea5zna'>nevent1q…5zna</a><br/>_________________________<br/><br/>When I read the sentence, &#34;We could be falling through the enormous event horizon of an enormous black hole right now&#34;, my first thought was &#34;yes, this applies to all spacetimes whose curvature is sufficiently small&#34;. But I was still amazed by how directly we can show this with the Kruskal-Szeres Penrose diagram. Thanks for explaining! 2024-11-21T21:26:33Z https://njump.me/nevent1qqsv2ettvkzmfkp40j6j69xfd259pxp9x53mp5dykmayslyy92huh4qzyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zutej09t In reply to <a href='/nevent1qqsdpxarpxmx3vzs4jwq967vuurjr3gh3pvfu9ncn35mnyeqaa3e66gcgrkzn'>nevent1q…rkzn</a><br/>_________________________<br/><br/>&gt; I don&#39;t see what it could possibly mean.<br/><br/>My brain autocompleted &#34;the ripples might be smaller&#34; as &#34;the expected amplitude-squared of the quantum harmonic oscillator associated with a particular wavemode of the neutrinos might be smaller&#34;. Normally, in QFT, we take care of this possibility by renormalizing the field strength \( Z_\phi \) to 1 by rescaling the field. 2024-11-02T22:34:15Z https://njump.me/nevent1qqsxswejcq28v9mr3tplgckd7vqarejhp2fgylscec04zzeywjxrj5gzyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zuxvhd7t In reply to <a href='/nevent1qqsxfkhhvunkwk93dlvzvza77z3eyhqalrqvg4ak5xdxsdqn0h5uh8gmvurx3'>nevent1q…urx3</a><br/>_________________________<br/><br/>You&#39;re right: all particles in QFT are &#34;ripples&#34; in quantum fields, and neutrinos are ripples in the neutrino fields. These ripples are in principle as &#34;strong&#34; as the ripples of any other particles out there, but the neutrino ripples just don&#39;t really interact with the ripples of the particles our measurement instruments are made of that much. That&#39;s why we mostly don&#39;t see them 2024-11-02T08:35:52Z https://njump.me/nevent1qqsw9fxgacwlhksx59m8h37rlf8gf9ny8nf7y0x55q34fkqg62aprjqzyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zuv7qs6d In reply to <a href='/nevent1qqsxc0h86yamd63xnd8ewl0cvk7sd5cwml8kee8kkpxnvrycxnydmmsvu9npt'>nevent1q…9npt</a><br/>_________________________<br/><br/>completely apart from the quantum nonsense: that recent dip in the polls looks more like a random Poisson fluke than anything else - especially because the trend has been accelerating upwards for the last two decades. 2024-10-24T20:10:35Z https://njump.me/nevent1qqswhn6eltzfzrwpeu85ntcjhxy8wgwpg0a0czy3ufplz4ce29pxt5gzyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zuwr8htk In reply to <a href='/nevent1qqspstpt5vdeu0ukunp5t0zuenh3ptedt45382f445hc03hthkqjvqg3k3at7'>nevent1q…3at7</a><br/>_________________________<br/><br/>Personally, for some reason I never really notice the lip-speech mismatch unless I&#39;m paying conscious attention to it. I mostly just watch programs dubbed into either English or French depending on my day-to-day mood. 2024-09-12T13:51:36Z https://njump.me/nevent1qqsd2d3gkn0n0jrqtx9eggajl9d58l8mr0gv5glrsvg9nul0vu8ckfqzyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zuhphcwp In reply to <a href='/nevent1qqsfwdkvcrllg2lhgt33cfe433q7f5t7q60hvg4gfpf2fs8w8zkkx3q9tr07q'>nevent1q…r07q</a><br/>_________________________<br/><br/>Those are some really good points! It completely slipped my attention that it&#39;s not End(V), but just its subspace formed by lowering an index of so(p, q) that&#39;s isomorphic to the bivectors.<br/><br/>Also, you&#39;re completely right that k-vectors don&#39;t encode shape information and that you can deform the parallelograms representing them arbitrarily. I glossed over that in the post, but now that I&#39;m rereading it, it really sounds like too much simplification. Also, I kinda ignored the non-blade-k-vector thing for simplicity (there&#39;s the nice example of the spacetime bivector \(\gamma_0 \wedge \gamma_1 + \gamma_2 \wedge \gamma_3\) that can&#39;t be represented as a parallelogram).<br/><br/>And I also fully agree with your intuition for k-forms! What I&#39;ve started doing is imagining 2-forms as a kind of &#34;extruded raster&#34; with a specific orientation, which you can intersect with a bivector, and then you look through it and count the &#34;cells&#34; that are &#34;blocked&#34; by the bivector (I&#39;ve tried to depict what I mean in Blender). But that was sorta out of the scope for the post :D<br/> <img src="https://media.mathstodon.xyz/media_attachments/files/113/101/694/480/175/472/original/97f0a423ab47c15d.png"> <br/> <img src="https://media.mathstodon.xyz/media_attachments/files/113/101/695/694/245/515/original/36650126e34f3e4b.png"> <br/> 2024-09-08T11:28:53Z https://njump.me/nevent1qqsrtqpesmgak9cyywpspkhk0s5uxfyrfknu4wymh2g5e2trepxpeuczyz4cxk0awysdzydms03k0dz6an0k48vgr4mw7e5qz9agkn8q2k5zu5nkg9r New blog post: Salvaging the useful parts from the cult - a 2-year review of geometric algebra<br/><br/>In this post, I argue that a lot of the advantageous didactical techniques of geometric algebra are not exclusive to Clifford algebras, and that we are mostly better off reformulating them in classical maths and dropping the &#34;geometric algebra&#34; banner.<br/><br/><a href="https://ash64.eu/assets/ga_review.pdf">https://ash64.eu/assets/ga_review.pdf</a> 2024-09-07T13:22:32Z