Title: First-order phase transitions in the heavy quark region of lattice QCD at high temperatures and high densities Show Chinese title

Title: 重夸克区域中格点QCD的一阶相变在高温和高密度下

Abstract: If there is a first-order phase transition in the light quark region of 2+1-flavor finite temperature and density QCD and if the region of the first-order phase transition expands with increasing density as suggested by several studies, then, at very high densities, we may expect that the first-order phase transition region expands into the heavy quark region of QCD, where we can perform efficient large scale simulations by adopting an effective theory of heavy quark QCD based on the hopping parameter expansion. In the heavy quark region of QCD, we have another first-order phase transition region around the heavy quark limit at zero density. By numerical simulations of effective heavy quark QCD, we found that, the first-order transition at zero density turns into a crossover as the chemical potential is increased, but, when we increase the chemical potential further, the change in the plaquette value near the crossover point becomes much steeper. This may be suggesting reappearance of the first-order phase transition. In this talk, we first show the nature of the phase transition of phase-quenched finite density QCD in the heavy quark region and then study the effect of the complex phase to discuss whether the QCD phase transition changes again to a first-order phase transition at very high densities. Show Chinese abstract

Abstract: 如果在2+1味有限温度和密度的QCD中轻夸克区域存在一阶相变，并且如一些研究所示，随着密度增加，一阶相变区域扩大，那么在极高密度下，我们可能会预期一阶相变区域扩展到QCD的重夸克区域，在那里我们可以采用基于跳跃参数展开的重夸克QCD有效理论进行高效的大规模模拟。 在QCD的重夸克区域，我们在零密度的重夸克极限附近有另一个一阶相变区域。 通过有效重夸克QCD的数值模拟，我们发现，当化学势增加时，零密度下的一阶相变会转变为交叉相变，但当我们进一步增加化学势时，交叉点附近的平面子值变化会变得更为陡峭。 这可能表明一阶相变的重新出现。 在本次报告中，我们首先展示重夸克区域中相位冻结有限密度QCD的相变性质，然后研究复数相位的影响，以讨论在极高密度下QCD相变是否会再次变为一阶相变。