R&D

A broad introduction to and overview of Ethereum research is available at Ethereum 2 and alternative PoS implementations, however this is now somewhat outdated.

Sharding:

• Sharding phase 1 spec
• Sharding FAQ
• Ethereum Research Sharding Compendium
• Sharding implementations;

The above links also link to many topics that are in the sharding roadmap, such as:

• eWASM,
• Casper proof of stake,
  • Search results on ethresear.ch
  • Proof of Stake FAQ
• zk-STARKs, e.g. videos here, here and here, as well as a paper here (the abstract is a more succinct intro than the videos), while the full paper is more detailed; and
• more.

Ethereum research communication channels

• Ethereum research Discourse forum. An introduction to the site is here, which includes onboarding packets for potential collaborators with generic research and programming language theory;
• Ethereum research repo; and
• Ethereum research gitter Channel.

Many research topics are related to improving scalability, but other research topics and categories are available at the Ethereum research Discourse forum, and there are others that improve scalability but also improve other properties, e.g. security, decentralization, and transparency.