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Spontaneous avalanche dephasing in large Rydberg ensembles
T Boulier1,2, E Magnan1,2, C Bracamontes1
1Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, College Park, Maryland 20742 USA.
Physical Review. A
|August 28, 2024
Summary
Spontaneous contaminant states cause rapid dephasing in Rydberg ensembles, limiting coherent interactions. This study confirms faster dephasing onset with increasing atom numbers, suggesting clustered growth mechanisms.
Area of Science:
- Atomic, Molecular, and Optical Physics
- Quantum Information Science
Background:
- Spontaneous contaminant states lead to strong dipole-exchange interactions.
- These interactions cause rapid dephasing in many-body Rydberg ensembles, impacting coherent control.
- Dephasing is a runaway process, where initial contaminant atoms accelerate further contaminant production.
Purpose of the Study:
- Investigate the time dependence of contaminant-induced dephasing in Rydberg ensembles.
- Examine the impact of Rydberg population on excitation dynamics.
- Explore mechanisms driving the rapid onset of dephasing.
Main Methods:
- Employed stroboscopic techniques and a pump-probe experimental setup.
- Created excess Rydberg population using a "pump" transition.
- Probed the system's response using a separate "probe" Rydberg transition.
Main Results:
- Observed reduced resonant pumping rates and broadened excitation profiles with increasing pump Rydberg population.
- Measured a population growth timescale significantly shorter than predicted by mean-field models.
- Confirmed that dephasing onset time scales inversely with atom number, supporting clustered growth.
Conclusions:
- The rapid dephasing in Rydberg ensembles is driven by clustered growth mechanisms, not homogeneous processes.
- Stroboscopic techniques and cryogenic temperatures can mitigate spontaneous broadening effects.
- Controlling contaminant states is crucial for realizing proposals utilizing coherent Rydberg interactions.
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