AI Assistant Writes 14,500 Lines of Rust Code for CMB Spectral Distortions

Spectroxide, a newly released open-source code package, consists of around 14,500 lines of Rust programming, a Python interface, and roughly 400 automated tests developed with the help of an AI assistant named Claude Code, under the guidance of human physicists. This solver addresses the photon Boltzmann equation, considering factors like Compton scattering, double Compton emission, and Bremsstrahlung from a redshift of z ~ 5 × 10^6 to the present, accommodating arbitrary photon and heat injections. Previously, no fully open-source code of this nature was available. The developers confirmed their findings against analytic limits, published spectra, and existing Green's function tables, showcasing a case study in AI-assisted scientific computing that revealed physics errors overlooked by the automated tests.