标题： 相图，约束弦和向列极性物质中的新普适类 显示英文标题

标题： Phase diagram, confining strings, and a new universality class in nematopolar matter

摘要： 我们研究了一个具有共存向列序和极序的系统的最小模型，其中一种场倾向于有序，而另一种场则偏好各向同性。 在强耦合下，有序场使各向同性场对齐，锁定它们的方向。 相图揭示了三个不同的相——向列-极相（对齐的序）、向列相（独立的序）和各向同性相（序消失），这些相由连续和不连续的转变分隔，包括一个三相点和一个三临界点。 我们发现向列-极相到向列相的转变具有独特的临界标度，不同于标准的向列或极序普适类。 此外，在锁定的向列-极相中，我们表明向列$+1/2$拓扑缺陷对通过具有恒定张力的弦连接并被限制。 这些弦来源于对齐取向序的挫败，可以解释为$+1$极拓扑缺陷的伸长核心。 当一个足够强的背景场与极序耦合时，所有拓扑缺陷都会被排出该区域。 分析预测通过数值模拟得到了定量验证。 显示英文摘要

摘要： We study a minimal model of a system with coexisting nematic and polar orientational orders, where one field tends to order and the other prefers isotropy. For strong coupling, the ordered field aligns the isotropic one, locking their orientations. The phase diagram reveals three distinct phases--nematopolar (aligned orders), nematic (independent orders), and isotropic (vanishing orders)--separated by continuous and discontinuous transitions, including a triple and a tricritical point. We find unique critical scaling for the nematopolar-nematic transition, distinct from standard nematic or polar universality classes. Additionally, in the locked nematopolar phase, we show nematic $+1/2$ topological defect pairs are connected and confined by strings with constant tension. These strings arise from frustration in locking the orientational orders and can be interpreted as elongated cores of $+1$ polar topological defects. When a sufficiently strong background field couples to the polar order, all topological defects are expelled from the region. Analytical predictions are quantitatively confirmed by numerical simulations.