标题： 量子效应对尖晶石高阶U(1)自旋液体的影响：夹线奇点、自旋向列相以及与氧化物材料的联系 显示英文标题

标题： Quantum effects on pyrochlore higher-rank U(1) spin liquids: Pinch-line singularities, spin nematics, and connections to oxide materials

摘要： 受尖晶石氧化物磁性的启发，我们考虑了在尖晶石晶格上最一般的对称性允许的最近邻Kramers交换哈密顿量中的量子涨落效应。 在经典层面上，该哈密顿量表现出丰富的经典自旋液体景观和多种非常规磁相。 相比之下，对于量子模型，仍有许多不清楚的地方，其中量子涨落有可能改变经典景观并稳定新的磁相。 采用最先进的伪费米子功能重整化群计算方法对自旋$1/2$模型进行研究，我们在相关截面上确定了量子相图，其中经典模型包含一种代数节点秩-2自旋液体和自旋向列序。 我们发现参数空间中存在大片区域，在这些区域中偶极磁序是不存在的，并且基于关联函数中的已知特征，我们认为这一非常规区域由由量子涨落稳定的多个不同相组成。 我们的结果暗示了自旋向列相的存在，并且我们识别了经典秩-2自旋液体的量子对应物。 此外，我们强调了评估量子和热涨落微妙相互作用的重要性，以解决关于Yb$_2$Ti$_2$O$_7$中磁序性质的实验结果。 显示英文摘要

摘要： Motivated by the magnetism of pyrochlore oxides, we consider the effect of quantum fluctuations in the most general symmetry-allowed nearest-neighbor Kramers exchange Hamiltonian on the pyrochlore lattice. At the classical level, this Hamiltonian exhibits a rich landscape of classical spin liquids and a variety of nonconventional magnetic phases. In contrast, much remains unclear for the quantum model, where quantum fluctuations have the potential to alter the classical landscape and stabilize novel magnetic phases. Employing state-of-the-art pseudo-fermion functional renormalization group calculations for the spin-$1/2$ model, we determine the quantum phase diagram at relevant cross-sections, where the classical model hosts an algebraic nodal rank-2 spin liquid and a spin nematic order. We find large regions in parameter space on which dipolar magnetic order is absent and, based on known fingerprints in the correlation functions, we suggest that this nonconventional region is composed of an ensemble of distinct phases stabilized by quantum fluctuations. Our results hint at the existence of a spin nematic phase, and we identify the quantum analog of the classical rank-2 spin liquid. Furthermore, we highlight the importance of assessing the subtle interplay of quantum and thermal fluctuations in reconciling the experimental findings on the nature of magnetic order in Yb$_2$Ti$_2$O$_7$.