CAREER: Coherent Single-Photons for Quantum Information

West Virginia University Research Corporation, Morgantown WV

Investigators

Abstract

Non-Technical Abstract: This award is funded by the Condensed Matter Physics program in the Division of Materials Research, the Physics at the Information Frontier program in Physics and the EPSCoR program. Quantum computation and communication offer great potential benefits to processing power and communication security by exploiting the non-intuitive properties of quantum mechanics. Photons will play an active part in future quantum information processing schemes, and semiconductor nanostructures called quantum dots are likely candidates to act as photon sources. Currently, however, photons produced by quantum dots are not suitable because of spectral diffusion experienced by the dots. The goal of this research project is to identify, model, and establish effective strategies to mitigate the factors responsible for spectral diffusion. The project involves graduate and undergraduate students who are being trained in optical and spectrographic measurement techniques, quantum optics, and condensed matter physics. Also integral to the project is the development, evaluation, and dissemination of an optics-related learning module for 4-H youth groups in West Virginia. The optics learning module fills a gap in the physical science curriculum available to 4-H group leaders, and will improve the students' science literacy and increase the number pursuing science-related careers. Volunteers from graduate and undergraduate physics societies are involved in the development and testing of the learning module, whereby they gain valuable outreach and educational experience that will help prepare them for future public education efforts. Technical Abstract: Photons emitted by quantum dots are potentially important in a number of quantum information processing applications, but because their coherence is currently non-ideal, that potential remains severely limited. The level of coherence of quantum dot photons is reduced by spectral diffusion due to interactions between a dot and its local environment, specifically fluctuations in the nearby charge distribution. In order to significantly improve the degree of coherence of quantum dot photons there is a critical need to identify and be able to control the environmental and external sources of spectral diffusion in the dots. The goal of the research project is to characterize the magnitude and timescale of spectral diffusion under different experimental conditions, model the interaction of the dots and the environment, and design photon sources with reduced or no spectral diffusion. The rationale for this approach is that reducing or eliminating spectral diffusion in a variety of situations is expected to enable the design of quantum dot-based photon sources with significantly higher fidelity performance than is currently possible in interference-based quantum information processing protocols. A complementary outreach effort involves graduate and undergraduate students in the design, evaluation, and state-wide dissemination of an optics-related 4-H learning module.