Slow group velocity and Cherenkov radiation

Area of Science:

• Quantum Optics
• Electromagnetism
• Atomic Physics

Background:

• Vavilov-Cherenkov radiation is typically emitted when charged particles exceed the phase velocity of light in a medium.
• Coherent driving of a medium can significantly alter its optical properties, including refractive index and group velocity.
• Ultraslow group velocities can lead to unique light-matter interaction phenomena.

Purpose of the Study:

• To theoretically investigate the influence of ultraslow group velocities on Vavilov-Cherenkov radiation emission.
• To analyze the geometrical characteristics of the radiation cone under conditions of ultraslow group velocity.
• To identify specific physical systems where these effects can be observed.

Main Methods:

• Theoretical modeling of Vavilov-Cherenkov radiation in a coherently driven medium.
• Analysis of the relationship between group velocity and radiation cone aperture.
• Consideration of a specific example involving ultracold atomic gases.

Main Results:

• Ultraslow group velocities drastically reduce the aperture of the group cone where radiation intensity peaks.
• The group cone aperture becomes significantly smaller than the cone predicted by the standard Cherenkov coherence condition.
• This singular behavior is theoretically predicted for coherently driven ultracold atomic gases.

Conclusions:

• Ultraslow group velocities fundamentally alter Vavilov-Cherenkov radiation emission patterns.
• The findings suggest novel possibilities for controlling and observing Cherenkov radiation in tailored quantum systems.
• Coherently driven ultracold atomic gases provide a promising platform for experimental verification.