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Will Future Generations Think We're Gross?

https://chillphysicsenjoyer.substack.com/p/will-future-generations-think-were
1•crescit_eundo•2m ago•0 comments

Kernel Key Retention Service

https://www.kernel.org/doc/html/latest/security/keys/core.html
1•networked•3m ago•0 comments

State Department will delete Xitter posts from before Trump returned to office

https://www.npr.org/2026/02/07/nx-s1-5704785/state-department-trump-posts-x
1•righthand•6m ago•0 comments

Show HN: Verifiable server roundtrip demo for a decision interruption system

https://github.com/veeduzyl-hue/decision-assistant-roundtrip-demo
1•veeduzyl•7m ago•0 comments

Impl Rust – Avro IDL Tool in Rust via Antlr

https://www.youtube.com/watch?v=vmKvw73V394
1•todsacerdoti•7m ago•0 comments

Stories from 25 Years of Software Development

https://susam.net/twenty-five-years-of-computing.html
2•vinhnx•8m ago•0 comments

minikeyvalue

https://github.com/commaai/minikeyvalue/tree/prod
3•tosh•12m ago•0 comments

Neomacs: GPU-accelerated Emacs with inline video, WebKit, and terminal via wgpu

https://github.com/eval-exec/neomacs
1•evalexec•17m ago•0 comments

Show HN: Moli P2P – An ephemeral, serverless image gallery (Rust and WebRTC)

https://moli-green.is/
2•ShinyaKoyano•21m ago•1 comments

How I grow my X presence?

https://www.reddit.com/r/GrowthHacking/s/UEc8pAl61b
2•m00dy•23m ago•0 comments

What's the cost of the most expensive Super Bowl ad slot?

https://ballparkguess.com/?id=5b98b1d3-5887-47b9-8a92-43be2ced674b
1•bkls•23m ago•0 comments

What if you just did a startup instead?

https://alexaraki.substack.com/p/what-if-you-just-did-a-startup
3•okaywriting•30m ago•0 comments

Hacking up your own shell completion (2020)

https://www.feltrac.co/environment/2020/01/18/build-your-own-shell-completion.html
2•todsacerdoti•33m ago•0 comments

Show HN: Gorse 0.5 – Open-source recommender system with visual workflow editor

https://github.com/gorse-io/gorse
1•zhenghaoz•33m ago•0 comments

GLM-OCR: Accurate × Fast × Comprehensive

https://github.com/zai-org/GLM-OCR
1•ms7892•34m ago•0 comments

Local Agent Bench: Test 11 small LLMs on tool-calling judgment, on CPU, no GPU

https://github.com/MikeVeerman/tool-calling-benchmark
1•MikeVeerman•35m ago•0 comments

Show HN: AboutMyProject – A public log for developer proof-of-work

https://aboutmyproject.com/
1•Raiplus•35m ago•0 comments

Expertise, AI and Work of Future [video]

https://www.youtube.com/watch?v=wsxWl9iT1XU
1•indiantinker•36m ago•0 comments

So Long to Cheap Books You Could Fit in Your Pocket

https://www.nytimes.com/2026/02/06/books/mass-market-paperback-books.html
3•pseudolus•36m ago•1 comments

PID Controller

https://en.wikipedia.org/wiki/Proportional%E2%80%93integral%E2%80%93derivative_controller
1•tosh•41m ago•0 comments

SpaceX Rocket Generates 100GW of Power, or 20% of US Electricity

https://twitter.com/AlecStapp/status/2019932764515234159
2•bkls•41m ago•0 comments

Kubernetes MCP Server

https://github.com/yindia/rootcause
1•yindia•42m ago•0 comments

I Built a Movie Recommendation Agent to Solve Movie Nights with My Wife

https://rokn.io/posts/building-movie-recommendation-agent
4•roknovosel•42m ago•0 comments

What were the first animals? The fierce sponge–jelly battle that just won't end

https://www.nature.com/articles/d41586-026-00238-z
2•beardyw•50m ago•0 comments

Sidestepping Evaluation Awareness and Anticipating Misalignment

https://alignment.openai.com/prod-evals/
1•taubek•50m ago•0 comments

OldMapsOnline

https://www.oldmapsonline.org/en
2•surprisetalk•53m ago•0 comments

What It's Like to Be a Worm

https://www.asimov.press/p/sentience
2•surprisetalk•53m ago•0 comments

Don't go to physics grad school and other cautionary tales

https://scottlocklin.wordpress.com/2025/12/19/dont-go-to-physics-grad-school-and-other-cautionary...
2•surprisetalk•53m ago•0 comments

Lawyer sets new standard for abuse of AI; judge tosses case

https://arstechnica.com/tech-policy/2026/02/randomly-quoting-ray-bradbury-did-not-save-lawyer-fro...
5•pseudolus•53m ago•0 comments

AI anxiety batters software execs, costing them combined $62B: report

https://nypost.com/2026/02/04/business/ai-anxiety-batters-software-execs-costing-them-62b-report/
1•1vuio0pswjnm7•54m ago•0 comments
Open in hackernews

Show HN: Differentiable Quantum Chemistry

https://github.com/lowdanie/hartree-fock-solver
52•lowdanie•2w ago

Comments

articulatepang•2w ago
This is great! Lovely to see a clean new codebase implementing quantum chemistry algorithms like Hartree-Fock. I remember using Molpro at my fist job. Venerable and comprehensive it may be, but it is some hoary Fortran code for sure.
lowdanie•2w ago
Thanks!
farhanhubble•2w ago
I get excited every time I see a "Differentiable X" library, but this one had me the most excited! Seeing the methane molecule acquire its geometry is so cool. Can it work with more complex molecules like small amino acids?
lowdanie•2w ago
The short answer is yes, but either memory (if the electron integrals are cached) or runtime (if they are not cached) currently scales like O(n^4) where n is the number of atoms.

In cached mode, it can currently jit compile the graph for molecules of around 10 atoms in ~5 minutes on one T4 gpu. Once the graph is compiled, the actual geometry optimization only takes a few seconds.

I’m working on optimizations that improve the scaling behavior (such as density fitting) with the goal of achieving similar or even better performance for molecules with ~50 atoms.

nynx•2w ago
Incredible work!
lowdanie•2w ago
Thanks!
n_u•2w ago
This looks super cool! I don't know much about Quantum Chemistry. Can this model interaction between molecules?
shrx•2w ago
In quantum chemistry, you decide where the bonds should be drawn. Internally, it's all an electron density field. So yes, you can model chemical reactions, for example by constraining the distance between two atoms, and letting everything else reach an equilibrium.
lowdanie•2w ago
Theoretically yes, but the method that is currently implemented (Hartree Fock) is notoriously inaccurate for molecular interactions. For example it does not predict the Van Der Waals force between water molecules.

I’m planning to add support for an alternative method called density functional theory which gives better results for molecular interaction.

montecarl•2w ago
When I read this, I thought that the author would be calculating the derivative of the potential energy with respect to nuclear charge for some reason. Here, the derivative being evaluated appears to be the atomic forces, using jax magic, as opposed to the standard Hellmann-Feynman theorem approach.

Calculating the derivative of the energy with respect to nuclear charge would be fun, as it would let you perform some type of "alchemy" smoothly changing from one element to another. I'm not sure that has any practical use.

I read a paper a while back doing something alchemical that I guess this reminded me of: https://pubs.aip.org/aip/jcp/article-abstract/133/8/084104/1...

lowdanie•2w ago
Since the gradients are computed with jax, the library can be used to differentiate with respect to all inputs including nuclear charge and basis set parameters (exponents and contraction coefficients). I agree that computing gradients for the nuclear charges could be interesting in the context of molecular design.

But for the colab demo I thought that sticking to nuclear positions (i.e atomic forces) would be easier to visualize.

empiricus•2w ago
Trying to read the math behind quantum chemistry, it is never clear to me which parts are fundamental, which parts are tricks, which parts are needed just for close form expressions, which parts are computational approximations, and which are the limitations? For a subject that should be fundamental for future technological advances, and highly dependent on the growth of computation resources, it seems to me exceptionally opaque and I suspect not well presented?
lowdanie•2w ago
In a nutshell, the only approximation in Hartree Fock is the assumption that the electronic wave function has a very specific form. Namely, that it is a Slater determinant of orbitals, and that each orbital is a linear combination of atomic orbitals from a fixed basis set. The linear coefficients of the orbitals are then solved for via the (exact) variational method.

Of course, the true wave function is generally not a Slater determinant. In particular, electrons in a Slater determinant with different spins are uncorrelated.

The standard approach to resolving this is density functional theory. In that model, the main approximation is the choice of an “exchange correlation functional” which approximates the electron exchange and correlation energy. The choice of a functional is unfortunately a dark art in the sense that they can only be evaluated empirically rather than from first principles.

The classic reference for Hartree Fock is Modern Quantum Chemistry by Szabo and Ostland: https://books.google.com/books/about/Modern_Quantum_Chemistr...

It is very well written and I highly recommend it.

I also wrote up some notes here: https://www.daniellowengrub.com/blog/2025/07/26/scf

empiricus•2w ago
Hi, thanks for the recommendations. I looked a little at the book, basically at the end we can compute some properties for small molecules sitting alone in space? What about arbitrary molecules, interacting? Or computing reaction rates? In a solvent? My understanding is that there are some algorithms for all of these, and there is probably progress made, but I never seen (online) anyone complaining that we cannot compute even this basic chemistry. I feel like we should care more about this problem.
lowdanie•2w ago
From my understanding, accurate simulations at the electron level (post Hartree Fock / DFT) are currently limited to 100 atoms (on a gpu cluster this can take hours or days). Maybe this can be pushed to 1000 atoms with aggressive optimization techniques like FMM.

So at this level of simulation it is currently only possible to simulate one medium size molecule or the interaction of a few small ones.

To simulate larger systems, it is necessary to work at a (semi-)classical level of abstraction that approximates quantum mechanics. For example using molecular dynamics to essentially simulate a fluid with a ball and springs model. In this case, electron level simulation can still be useful for deriving heuristics (conceptually, the spring tension).

I completely agree that it’s interesting to investigate how far the electron level simulation can be pushed.