淬火QCD中非零动量下的实时拓扑速率
Real-time topological rate at non-zero momentum in quenched QCD
AI总结：
本研究在淬火格点QCD中，通过HLT方法结合控制多类极限，计算了非零动量下的实时拓扑速率，为全QCD中该物理量的确定奠定了基础。
AI中文摘要：
我们开展了淬火格点QCD在温度T≃1.24 T_c≃360 MeV下非零动量处实时拓扑速率的概念验证数值研究，这是确定全QCD中该物理量的重要一步。我们采用的策略已应用于计算纯杨-米尔斯理论和全QCD中的 sphaleron 速率，该策略通过求解合适的逆问题来提取速率，求解时将Hansen-Lupo-Tantalo（HLT）方法应用于拓扑荷密度的热欧几里得时间关联函数。该方法需要控制三个不同的极限：连续极限、求解HLT逆问题时使用的弥散宽度消失的极限，以及计算拓扑荷密度关联函数时使用的平滑半径消失的极限。我们的格点计算基于规范作用量的标准Wilson离散化，使用了三组规范系综，其中时间点数目N_τ最高为16，以实现可控的连续极限。所有情况下我们都采用了纵横比LT=4，这使我们能够计算动量p/T~10时的拓扑速率。
英文摘要：
We present a proof-of-concept numerical study of the real-time topological rate at non-zero momentum in quenched lattice QCD at a temperature $T\simeq 1.24 \, T_c \simeq 360$ MeV, as an important step toward the determination of this quantity in full QCD. Our strategy, already applied to compute the sphaleron rate in pure Yang--Mills and in full QCD, extracts the rate from the resolution of an appropriate inverse problem, solved applying the Hansen--Lupo--Tantalo (HLT) method to the thermal Euclidean time-correlator of the topological charge density. This method requires to control three different limits: continuum limit, limit of vanishing smearing width used in the HLT inverse problem resolution, and limit of vanishing smoothing radius used in the topological charge density correlator computation. Our lattice calculation is based on the standard Wilson discretization for the gauge action, and on three gauge ensembles with up to $N_τ=16$ temporal points to achieve a controlled continuum limit. In all cases we employed an aspect ratio $LT=4$, which allowed us to compute the topological rate up to momenta as large as $p/T \sim 10$.
