标题： 二维QCD强耦合展开的Grassmann张量方法 显示英文标题

标题： Grassmann tensor approach for two-dimensional QCD in the strong-coupling expansion

摘要： 我们提出一种张量网络方法，用于在非零化学势下二维QCD的强耦合展开，使用交错夸克。 在规范和费米子作用量中展开玻尔兹曼因子后，所有规范场都可以被精确积分掉，并且可以使用格拉斯曼高阶张量重正化群方法来计算配分函数。 该方法被修改以计算夸克数密度和手征凝聚的$\mu$依赖性，直到$\beta^3$阶，完全避免高阶项渗入结果中。 尽管该展开本身仅在小$\beta<0.1$时是对完整理论的良好近似，但通过谨慎选择的拟合可以扩展其范围。 此外，这些拟合还为临界化学势提供了有价值的$\beta$展开。 显示英文摘要

摘要： We present a tensor-network approach for the strong-coupling expansion of two-dimensional QCD with staggered quarks at non-zero chemical potential. After expanding the Boltzmann factor in the gauge and fermion actions, all gauge fields can be integrated out exactly and the partition function can be evaluated using the Grassmann higher-order tensor renormalization group approach. The method is modified to compute the $\mu$ dependence of the quark number density and the chiral condensate up to order $\beta^3$ with complete absence of higher-order terms infiltrating the result. Although the expansion itself is only a good approximation to the full theory at small $\beta<0.1$, the range can be extended, by using judiciously chosen fits. Moreover, these fits also yield a valuable expansion in $\beta$ for the critical chemical potential.