Making Use of Phonons with Coupled Quantum Dots
Nov 07, 2013
from 11:00 AM to 12:00 PM
|Where||Engr. IV Bldg., Maxwell Room 57-124|
|Contact Name||Paul Simmonds|
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University of California, Merced
Phonons, quantized vibrations of an elastic structure, permeate the crystalline components of modern technology, and are central to the emerging research area termed ‘phononics’. Associated mainly with heat, lost energy and noise, phonons are encountered as such in many devices used in daily life. They also govern fundamental phenomena on the quantum level, from relaxation dynamics in nanostructures to superconductivity. In the development of solid state quantum technologies phonons are predominantly considered for the limitations they impose. Omnipresent electron-phonon interactions and the predominantly dissipative nature of phonons are a major source of decoherence of the atom-like quantum states hosted by low-dimensional solid state structures, such as quantum dots.
In contrast, here I will present on an effect in which phonons are made non-dissipative and coherent via the optically driven formation of a so called molecular polaron in a pair of quantum dots. I will review the essential concepts in the optical spectroscopy of coupled quantum dots, via which we will learn how to make quantum dots transparent by ‘shaking’ them. This induced optical transparency, the result of a Fano-type resonant quantum interference, reveals the molecular polaron and its coherent nature. The molecular polaron represents an enhancement of the interaction between the two dots, which demonstrates amplification of the visibility of molecular excitonic transitions and weakest coupling channels.
Dr. Scheibner is assistant professor at the University of California Merced, where he joined the School of Natural Sciences in 2009. Prior to his current appointment Dr. Scheibner was affiliated with the University of Wuerzburg, the University of New Mexico, and the Naval Research Laboratory. As an exchange student coming from the University of Wuerzburg in Germany he graduated with a M.S. degree in Physics from UNM in 1999. He returned to Wuerzburg and obtained the degree “Diplom Physiker”, and later in 2006 his doctoral degree, for experimental work on the dynamics of locally interacting spin carriers. In the meantime he has been visiting the Naval Research Laboratory in Washington DC, where he also started his work as postdoctoral researcher on double dot quantum dot molecules in 2005. His current research interest is in the optics of solid state based scalable artificial quantum systems.