Anomalous Broadening in Driven Dissipative Rydberg Systems

Area of Science:

• Atomic Physics
• Quantum Optics
• Condensed Matter Physics

Background:

• Rydberg atoms, highly excited atomic states, exhibit strong interactions.
• Coherent interactions of Rydberg atoms are crucial for quantum information processing and simulation.
• Understanding factors affecting Rydberg atom interactions is essential for advancing these fields.

Purpose of the Study:

• To investigate interaction-induced broadening of the two-photon 5s-18s transition in Rubidium-87 (87Rb) atoms.
• To quantify the relationship between atomic density, excitation strength, and transition linewidth.
• To identify the underlying mechanism responsible for the observed broadening.

Main Methods:

• Trapping 87Rb atoms in a 3D optical lattice.
• Performing two-photon spectroscopy on the 5s-18s transition.
• Varying atomic density and excitation strength to observe changes in spectral linewidth.
• Analyzing scattering properties (resonant and off-resonant).

Main Results:

• Observed a nearly two-orders-of-magnitude increase in linewidth with increasing atomic density and excitation strength.
• Attributed the broadening to resonant dipole-dipole interactions between 18s Rydberg atoms and blackbody-populated np states.
• Found the transition width is a single function of the steady-state Rydberg atom density.
• Resonant excitation rate matched a two-level system using the measured, not natural, linewidth.

Conclusions:

• Interaction-induced broadening significantly impacts the 5s-18s transition in 87Rb Rydberg atoms.
• The observed broadening mechanism, driven by dipole-dipole interactions, has potential negative implications for quantum technologies relying on coherent Rydberg atom interactions.
• Further research is needed to mitigate or control this broadening effect for practical applications.