xMoCo: Cross Momentum Contrastive Learning for Open-Domain Question Answering Nan Yang author Furu Wei author Binxing Jiao author Daxing Jiang author Linjun Yang author 2021-08 text Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 1: Long Papers) Chengqing Zong editor Fei Xia editor Wenjie Li editor Roberto Navigli editor Association for Computational Linguistics Online conference publication yang-etal-2021-xmoco 10.18653/v1/2021.acl-long.477 https://aclanthology.org/2021.acl-long.477/ 2021-08 6120 6129