论文标题
关于（3+1）D的出现的新观点
New perspectives on the emergence of (3+1)D expanding space-time in the Lorentzian type IIB matrix model
论文作者
论文摘要
IIB型矩阵模型是非扰动公式的有前途的候选者。尤其是在洛伦兹版本中，通过该模型的蒙特卡洛研究观察到（3+1）d扩展时空的出现。在这里，我们提供了有关（3+1）d扩大时空的新观点。首先，发现由模拟生成的矩阵配置是单数的，因为代表扩展3D空间的子膜片只有两个与Pauli矩阵相关的大特征值。由于用于避免模拟模型的符号问题的近似值而发生了这个问题。为了确认此猜想，应用了复杂的langevin方法来克服符号问题，而不是使用近似值。结果确实显示出与Pauli-Matrix结构明显不同，而（3+1）d的扩展行为仍未改变。还发现，在某个ANSATZ中获得的经典解决方案显示出具有平滑时空结构的a（3+1）d扩展行为。
The type IIB matrix model is a promising candidate for a nonperturbative formulation of superstring theory. In the Lorentzian version, in particular, the emergence of (3+1)D expanding space-time was observed by Monte Carlo studies of this model. Here we provide new perspectives on the (3+1)D expanding space-time that have arised from recent studies. First it was found that the matrix configurations generated by the simulation are singular in that the submatrices representing the expanding 3D space have only two large eigenvalues associated with the Pauli matrices. This problem was conjectured to occur due to the approximation used to avoid the sign problem in simulating the model. In order to confirm this conjecture, the complex Langevin method was applied to overcome the sign problem instead of using the approximation. The results indeed showed a clear departure from the Pauli-matrix structure, while the (3+1)D expanding behavior remained unaltered. It was also found that classical solutions obtained within a certain ansatz show quite generically a (3+1)D expanding behavior with smooth space-time structure.
