LMI Seminar: Ultrastrong coupling of electrons and polaritons in 2D settings

Zoom: https://us02web.zoom.us/j/2598032127?pwd=a1BnVHlvZVZ1ZGs0WWNtaXRCTlV5Zz09

Abstract:

The diversity of light-matter interactions accessible to a system is significantly limited by both the small size of an atom relative to the wavelength of the light it emits, and the small value of the fine-structure constant. Overcoming these limitations is a long-standing challenge. Recent theoretical and experimental breakthroughs have shown that systems such as graphene, boron nitride, and other 2D van der Waals materials can support strongly confined light in the form of plasmon/phonon polaritons. Due to their strong confinement, these polariton force us to recast the main assumptions for light-matter interactions. We identify cases in which the rate of two-photon spontaneous emission can compete with the rate conventional spontaneous emission, suggesting a new way of creating entangled photon pairs. Our findings also offer a potential testing ground for quantum electrodynamics in the ultrastrong coupling regime, and more generally, offer the ability to take advantage of the full electronic spectrum of an emitter, or to modify it. Finally, the seminar will touch upon several examples of such strong and ultrastrong interactions in different systems, revealing connections to the Cherenkov effect and to new experiments in laser-driven ultrafast electron microscopes.

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