Precision Measurements of the ^{138}Ba^{+} 6s^{2}S_{1/2}-5d^{2}D_{5/2} Clock Transition

Area of Science:

• Atomic Physics
• Quantum Metrology
• Spectroscopy

Background:

• Precise atomic transition frequencies and g-factors are essential for developing advanced atomic clocks.
• Previous measurements of the ^{138}Ba^{+} Landé g_{J} factor had limited accuracy.

Purpose of the Study:

• To measure the ^{138}Ba^{+} ^{2}S_{1/2}-^{2}D_{5/2} clock transition frequency with high accuracy.
• To determine the Landé g_{J} factor for the ^{2}D_{5/2} level of ^{138}Ba^{+} with improved precision.

Main Methods:

• High-precision laser spectroscopy was used to probe the ^{138}Ba^{+} ion.
• Frequency measurements were calibrated using a maser reference oscillator.
• Landé g_{J} factor was determined by analyzing the Zeeman effect in the presence of ac-magnetic fields.

Main Results:

• The ^{138}Ba^{+} clock transition frequency was measured as 170126432449333.31±(0.39)_{stat}±(0.29)_{sys} Hz.
• The Landé g_{J} factor for the ^{2}D_{5/2} level was determined to be 1.20036739(24), a 30-fold improvement.
• Systematic effects from ac-magnetic fields were identified and corrected for.

Conclusions:

• The study provides highly accurate values for the ^{138}Ba^{+} clock transition frequency and Landé g_{J} factor.
• The improved g-factor accuracy has implications for fundamental constant measurements and tests of physics theories.
• Accurate characterization of systematic effects is critical for high-precision atomic measurements.