Exploring the physics of spontaneous emission with an artificial atomic system

Exploring the physics of spontaneous emission with an artificial atomic system

Hard Condensed Matter & Atomic, Molecular and Optical Physics (AMO) seminar

Date

November 9, 2017 -
3:00pm to 4:00pm

Location

Howey N110

Affiliation

Stony Brook University Department of Physics and Astronomy

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Exploring the physics of spontaneous emission with an artificial atomic system

Abstract:

The question how irreversibility can emerge in quantum mechanics is central to the study of open quantum systems. A simple example is the exponential decay of an excited two-level atom as described by the Wigner-Weisskopf model of quantum optics, in which spontaneous photon emission is sometimes viewed as being driven by fluctuations of the surrounding vacuum. However, the Markov approximation underlying this model can be violated under certain conditions, and recent experiments on optical decay in photonic bandgap materials have indeed started to find deviations from its predictions.

We have recently realized an "artificial atom" in which the excited-state energy and the vacuum coupling can be controlled at will, thus allowing for a systematic exploration of spontaneous emission beyond the Markov approximation. Naively, a two-level atom may be viewed as a photon trap that is empty or full; we instead realize a microscopic trap for a single atom that can decay, under coherent external driving, by emitting the atom into the surrounding vacuum. The experiments are performed using an optical lattice geometry that provides arrays of such artificial atoms coupled to a one-dimensional matter waveguide. In my talk I will present experimental results on Markovian and strongly non-Markovian dynamics in this system, including exponential and partly reversible oscillatory decay, atom reabsorption, as well as a bound state for emission below the edge of the mode continuum that features an evanescent matter wave and which is the direct analog of the long-predicted atom-photon bound state in photonic bandgap materials. I will conclude with an outlook on future applications of our system in open-system many-body quantum physics.