CCAST, World Lab, Beijing 100080, Peoples R China
; Acad Sinica, Inst High Energy Phys, Beijing 100039, Peoples R China
The field variables (FV), the strength tensor (ST) and the topological charge density (TCD) of lattice SU(2) gauge field are: studied in the momentum space. The evolution behaviors of their Fourier components are monitored during the smoothing procedure. The high frequency components of the FV can not be eliminated by smoothing, but all the Fourier amplitudes of the ST are uniformly suppressed. The distribution of the TCD in Euclidean spacetime is highly smoothed. Based on these facts, we give a new interpretation of the structure of the smoothed gauge configurations and argue that the ultraviolet and infrared cutoff introduced by lattice discretization account for the suppression of the instanton size distribution at both the large size end and the: small size end. (C) 2000 Elsevier Science B.V. All rights reserved.