Stony Brook University
The quantitative understanding of spontaneous emission harks back to the early days of QED, when in 1930 Weisskopf and Wigner, using Dirac’s radiation theory, calculated the transition rate of an excited atom undergoing radiative decay. Their model, which describes the emission of a photon through coherent coupling of the atom’s dipole moment to the continuum of vacuum modes, reflects the view that spontaneous emission into free space, driven by vacuum fluctuations, is inherently irreversible.
In my talk, I will describe recent studies of the Weisskopf-Wigner model in a novel context that allowed us to go beyond the model’s usual assumptions. For this purpose, we created an array of microscopic atom traps in an optical lattice that emit single atoms, rather than single photons, into the surrounding vacuum. Our ultracold system, which provides a tunable matter-wave analog of photon emission in photonic-bandgap materials, revealed behavior beyond standard exponential decay with its associated Lamb shift. It includes partial backflow of radiation into the emitter, and the formation of a long-predicted bound state in which the emitted particle hovers around the emitter in an evanescent wave. My talk will conclude with an outlook on using our new platform for studies of dissipative many-body physics and (non)-Markovian matter-wave quantum optics in optical lattices.
About the speaker
In the Schneble laboratory, they load atoms from BECs into optical lattices, i.e. potentials realized by standing waves of laser light, in order to create and explore ultracold engineered quantum systems. With the help of such optical lattices, it thus becomes possible to address cutting-edge topics ranging from condensed matter physics to quantum information science, through direct quantum simulation. For example, the behavior of atoms in an optical lattice closely mimics that of electrons in a solid, but at a length scale that is three orders of magnitude larger and with exquisite control over all relevant parameters in a naturally defect-free system. Moreover, atoms in optical lattices can act as localized qubits (spins) with controllable interactions, making lattice-based atomic quantum systems a versatile platform for studying the fundamental science driving the development of modern quantum technologies.
More details can be found here.