SDP4Bit: Toward 4-bit Communication Quantization in Sharded Data Parallelism for LLM Training - Jia, Jinda; Xie, Cong; Lu, Hanlin; Wang, Daoce; Feng, Hao; Zhang, Chengming; Sun, Baixi; Lin, Haibin; Zhang, Zhi; Liu, Xin; Tao, Dingwen (Advances in Neural Information Processing Systems, 2024)