Speaker
Description
The gradient flow has become a powerful and versatile tool in lattice QCD calculations. At positive flow time, gauge and fermion fields are smoothed over a physical radius of order $\sqrt{t}$, providing an additional ultraviolet regulator that can simplify the construction and analysis of lattice observables. Physical quantities are then recovered by combining continuum extrapolations at fixed flow time with suitable procedures to connect flowed observables to the vanishing-flow-time limit.
In this talk I will review selected recent applications and developments of the gradient flow in lattice QCD. I will discuss the properties of flowed fields that are most relevant for current applications, with particular emphasis on the construction, normalization, and matching of flowed composite local operators. I will then discuss representative examples where the gradient flow has been used to define lattice observables that are difficult to access with standard approaches, or where its use has provided promising advantages compared with standard techniques. I will conclude with perspectives on the role of flow time as a physical scale and on the relation between flowed quantities and conventional continuum schemes.