Projects

In our project on quantum dots we investigate a variety of types of quantum dots. The material is mostly InAs on either GaAs or in InP nanowires. Based on these dots we want to develop single photon and entangled photon pair sources. Further we are studying the interfacing of quantum dot photons to photons generated in parametric down-conversion. (read more...)

In our project on Entangled Photon Pairs from Semiconductor Waveguides we are able to exploit the large optical nonlinearities that some semiconductors (e.g. GaAs) offer. Phase-matching is difficult and traditional quasi-phase-matching techniques, like periodic poling don't work in semiconductors. So far the most successful approach uses Bragg waveguides. (read more...)

Microcavity Exciton-Polaritons are half-light / half-matter quasiparticles in strongly coupled semiconductor microcavities. They have been shown to exhibit dynamic condensation at very high lattice temperatures due to their small effective mass. The strong four-wave mixing induced by the exciton-exciton scattering could be exploited for optical quantum information processing. (read more...)

Starting from a triple-slit experiment we are investigating higher-order, i.e. genuine Multi-Path Interferences for possible deviations from quantum mechanics as well as the possibility to represent quantum mechanics by hypercomplex (e.g. quaternion) numbers instead of complex ones. For this purpose we have a five-path interferometer and measure the ration of higher-order to regular interference. (read more...)

Publications

Funding

	Within the European Research Council Starting Grant EnSeNa - Entanglement from Semiconductor Nanostructures we work with Quantum Dots and with Microcavity Exciton-Polaritons to obtain entangled photon pairs from semiconductor nanostructures.
	The Austrian Science Fund (FWF) funds our work through the following projects: D-A-CH project "Integrated Sources of Entangled and Indistinguishable Photons" (I-2065, toegther with Christian Schneider, University of Würzburg and Stephan Reitzenstein, TU Berlin) and the D-A-CH project "Polariton-based single-photon sources" (I-2199, together with Chrstian Schneider, University of Würzburg and Atac Imamoglu, ETH Zurich) Doctoral Program "Atoms, Light and Molecules" (W-1259, Speaker: R. Wester) Lise-Meitner fellowship "Fundamental tests of quantum mechanics in optical waveguides" (M-01849, Robert Keil) Elise-Richter fellowship "Entanglement from Quantum Dots" (V-00375, Ana Predojevic)
	The Canadian Institute for Advanced Research supports all our research activities related to quantum communications and through its Quantum Information Science Program.

Collaborations

Student and staff exchange between European and Canadian Universities

Past Funding

• The Austrian Science Fund (FWF) funded our work on polariton entanglement through the standalone project "Polariton Entanglement" (P-22979-N16, 2011-2015, together with G. Strasser, TU Vienna).
• The Foundational Questions Institute (FQXi) funded our work on multipath interference through their Large Grant "Higher-order Interferences and Time in Alternatives to Quantum Theory" (2011-02814, 2011-2013, together with C. Brukner, University of Vienna).