Systematic Study of theSr87Clock Transition in an Optical Lattice

With ultracold ${}^{87}\mathrm{Sr}$ confined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to date of the ${}^{1}S_0\mathrm{\text{−}}{}^{3}P_0$ optical clock transition with a detailed analysis of systematic shifts (19 Hz uncertainty) in the absolute frequency measurement of 429 228 004 229 869 Hz. The high resolution permits an investigation of the optical lattice motional sideband structure. The local oscillator for this optical atomic clock is a stable diode laser with its hertz-level linewidth characterized by an octave-spanning femtosecond frequency comb.