The Physics & Astronomy Colloquium Series presents Edward Flagg of the West Virginia University on “Quantum Dots and Quantum Optics” on Friday, March 25, at 4:10 p.m. in Walter 245.
Edward Flagg
Abstract: Semiconductor quantum dots (QDs) are often called artificial atoms because charge carriers trapped within them have discrete energy levels in the fashion of atoms. They absorb and emit light at discrete wavelengths corresponding to those energy levels. Because of this, in many ways QDs behave like the canonical two-level quantum system, which makes them suitable for experiments involving the quantum nature of light, which is called quantum optics. For this reason and for their potential uses in quantum information applications, QDs attract great scientific interest.
One desirable quantum optical capability is the emission of identical, or indistinguishable photons. Such photons are necessary for many proposed quantum information processing protocols such as quantum repeaters, which would distribute entanglement along optical networks. I will discuss work investigating the indistinguishability of photons emitted by different QDs and address the challenges associated with obtaining indistinguishable photons. QDs are very sensitive to the conditions of their microscopic environment, enough so that a single electron trapped nearby causes a measurable change in the emission wavelength of the QD. This sensitivity makes obtaining indistinguishable photons difficult, but allows the measurement of charge dynamics in a microscopic volume with great precision.
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