发表机构
The University of Hong Kong; Harvard University; Flatiron Institute（香港大学; 哈佛大学; 平顿研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过量子蒙特卡洛研究，在半填充正方晶格上发现反铁磁Néel态与节线d波超导体之间存在二级去禁闭量子相变，两种序连续消失。
AI 中文摘要
我们提出了在半填充正方晶格上绝缘Néel态与节线$d$-波超导体之间转变的量子蒙特卡洛研究。我们使用电子的部分子表示（费米子自旋子和玻色子电荷子）进入了一个没有符号问题的受挫磁有序区域。两种部分子都在背景$\pi$-通量（因此电子经历零净通量）中运动，并与量子涨落的SU(2)格点规范场耦合。与早期直接对电子自由度进行的研究相比，我们发现了二级去禁闭量子相变的证据，在该相变中Néel和$d$-波超导序都连续消失。我们计算了具有与电子相同量子数的自旋子-电荷子复合体的关联函数：在$d$-波超导体内部发现了无隙狄拉克色散，在反铁磁体中转变为有隙色散。
英文摘要
We present a quantum Monte Carlo study of the transition between the insulating Néel state and the nodal $d$-wave superconductor on the square lattice at half-filling. We access a regime of frustrated magnetic order without a sign problem using a parton representation of the electron in terms of fermionic spinons and bosonic chargons. Both partons move in a background $π$-flux (so the electron experiences no net flux) and are coupled to a quantum fluctuating SU(2) lattice gauge field. In contrast to earlier studies directly on the electronic degrees of freedom, we find evidence for a second-order deconfined quantum phase transition at which both the Néel and $d$-wave superconductivity orders vanish continuously. We compute correlators of the spinon-chargon composite with the same quantum numbers as the electron: we find a gapless Dirac dispersion inside the $d$-wave superconductor, turning into a gapped dispersion in the antiferromagnet.
Comments17 pages, 7 figures
