标题： 纯胶子QCD中基于重叠的拓扑电荷密度关联函数的负性和接触部分的非可积性 显示英文标题

标题： The Negativity of the Overlap-Based Topological Charge Density Correlator in Pure-Glue QCD and the Non-Integrable Nature of its Contact Part

摘要： 我们利用基于重叠Dirac矩阵的算符离散化，在纯胶子QCD中计算了拓扑电荷密度的晶格两点函数。通过使用三个不同晶格间距的数据，表明相关函数的连续极限满足非零距离处的非正性要求。对于我们的重叠算符选择和Iwasaki规范作用量，发现当非常接近连续极限时，正核的大小约为~2a（a为晶格间距）。这一结果证实了基于重叠的拓扑电荷密度在对QCD路径积分有贡献的实际背景上是一个有效的局域算符，并且对于最近结果的一致性非常重要，这些结果表明QCD真空中存在低维的全局类膜拓扑结构。我们还确认了相关函数在短距离处的发散行为以及接触部分的非可积性质。 显示英文摘要

摘要： We calculate the lattice two-point function of topological charge density in pure-glue QCD using the discretization of the operator based on the overlap Dirac matrix. Utilizing data at three lattice spacings it is shown that the continuum limit of the correlator complies with the requirement of non-positivity at non-zero distances. For our choice of the overlap operator and the Iwasaki gauge action we find that the size of the positive core is ~2a (with a being the lattice spacing) sufficiently close to the continuum limit. This result confirms that the overlap-based topological charge density is a valid local operator over realistic backgrounds contributing to the QCD path integral, and is important for the consistency of recent results indicating the existence of a low-dimensional global brane-like topological structure in the QCD vacuum. We also confirm the divergent short-distance behavior of the correlator, and the non-integrable nature of the associated contact part.