Title: Improved Absolute Frequency Measurement of the 171Yb Optical Lattice Clock at KRISS Relative to the SI Second,
Abstract: We measured the absolute frequency of the $^1S_0$ - $^3P_0$ transition of
$^{171}$Yb atoms confined in a one-dimensional optical lattice relative to the
SI second. The determined frequency was 518 295 836 590 863.38(57) Hz. The
uncertainty was reduced by a factor of 14 compared with our previously reported
value in 2013 due to the significant improvements in decreasing the systematic
uncertainties. This result is expected to contribute to the determination of a
new recommended value for the secondary representations of the second.