[Discussion] Switching to a copyleft license? #455

With AI making it much easier to copy, translate, and build on existing code, switching future releases from MIT to GPLv3 or AGPLv3 could help keep more of that work available to the community. (This suggestion applies to all QuantumKitHub packages.)

Under MIT, someone can take our packages, improve them, and sell a closed-source version without sharing their changes. GPLv3 would require them to share the source when they distribute a version based on our code, while AGPLv3 also covers modified versions that people use over a network (e.g. some cloud simulation platform).

Others could still build commercial products, but users would retain the ability to inspect, modify, and share the covered code. That could help our work — and improvements built on it — remain a shared resource.

It wouldn’t guarantee contributions back to us or cover every independent rewrite, and existing MIT releases would remain available under MIT, but it would set a clearer expectation of sharing going forward.

For comparison, our friends working on YASTN and variPEPS use the GPL-3.0 license.