Long-Lived Coherence on a μHz Scale Optical Magnetic Quadrupole Transition

Area of Science:

• Atomic Physics
• Quantum Optics
• Spectroscopy

Background:

• The ^{1}S_{0}-^{3}P_{2} transition in ^{88}Sr is a magnetic quadrupole transition with potential for high-precision measurements.
• Metastable states like ^{3}P_{2} are crucial for developing advanced quantum technologies.

Purpose of the Study:

• To coherently excite the ultranarrow ^{1}S_{0}-^{3}P_{2} magnetic quadrupole transition in ^{88}Sr.
• To characterize the coherence properties and lifetime of the ^{3}P_{2} state.
• To explore potential applications in quantum computing and simulations.

Main Methods:

• Confining ^{88}Sr atoms in a state-insensitive optical lattice.
• Utilizing Ramsey spectroscopy and spin-echo sequences for coherence time measurements.
• Measuring the excitation fraction and linewidth of the transition.

Main Results:

• Achieved high excitation fractions (97(1)%) and narrow linewidths (58(1) Hz).
• Observed coherence times of 14(1) ms, extendable to 266(36) ms with spin-echo.
• Determined the ^{3}P_{2} level lifetime to be 110(31) min, matching theoretical predictions.

Conclusions:

• The study successfully demonstrates coherent excitation of a novel strontium clock transition.
• The long lifetime and coherence of the ^{3}P_{2} state are confirmed, validating theoretical models.
• These findings establish a new strontium atomic clock transition and enable applications in quantum technologies.