We will talk about our recent density matrix renormalization group (DMRG) studies of the superconductivity (SC) and sign structure in the square-lattice t-J model with the next-nearest-neighbor hopping t`. For the fermionic t-J model, we find d-wave SC for both t` > 0 and t` < 0 on wider system size. We further demonstrate that the hole pairing in both the SC and stripe phase can be attributed to an intrinsic Berry-phase-like sign structure in the system. By switching off the sign structure, both the SC and stripe phase becomes a Fermi liquid without hole pairing. In the bosonic t-J model, we map a quantum phase diagram including distinct quantum phases, several of which go far beyond the conventional paradigm of phase-coherent superfluidity expected for bosonic systems. These competing and intertwined orders reflect the frustrated interplay between doped holes and spin background that originates from the sign structure, which plays a crucial role in both fermionic and bosonic doped antiferromagnets.

Biography

龚寿书，大湾区大学物质科学学院教授。2010年于中国科学院研究生院获博士学位，2010至2017年在美国加州州立大学和美国强磁场国家实验室从事研究工作，2018年入职北京航空航天大学，2023年入职大湾区大学。近年来，与合作者在量子磁性和非常规超导电性的量子多体计算研究上取得一定进展。

Inviter: Gang Su