PROJECTS
Our project "Bright Entanglement via Dark States" (BRAIDS) aims at generating single time-bin entangled photon pairs from semiconductor quantum dots utilizing dark exciton states as metastable levels.
In our project UNAGI, we aim to experimentally investigate the nature of wave-particle duality and quantum interference beyond the well-understood realm of single-particle systems. The research project addresses fundamentally significant open questions about the quantum-classical border in the many-particle domain. Beyond fundamental tests of quantum physics phenomena, the project will also give rise to novel quantum states quantifiers, which can be used for benchmarking future large-scale quantum computation platforms.
The vision of the FWF-funded Cluster of Excellence Quantum Science Austria is to become the premier place in the world, in which to do research in fundamental quantum physics. We will achieve this through cooperation between all the quantum researchers working in Austria in the field of fundamental quantum physics.
The aim of the FFG/Quantum Austria project HuSQI is the coordinated acquisition and installation of closed-cycle cryogenic stations equipped with advanced electronic and optical equipment for the rapid characterization and uninterrupted operation of photonic and superconducting solid-state devices for forefront research in quantum science and new applications in quantum computation and communication.
In our research subgroup on Quantum Dots we work with GaAs/AlGaAs or InP/InAsP quantum dots, towards three main projects: (1) developing robust excitation schemes to generate single or entangled photon pairs (2) generating time-bin entangled photons (3) designing and fabricating photonic cavity structures for improved photon extraction efficiency.
In the D-A-CH project On-chip microlaser driven sources of indistinguishable photons for quantum networks we aim to combine the advantages of semiconductor quantum dots and Bragg-reflection waveguides in a single device. By exploiting the high optical nonlinearity of AlGaAs BRWs, we convert the single photons generated by an embedded quantum dot to telecom wavelengths via difference frequency generation.
In our project Tailoring single photon spectra for hybrid quantum networks we develop time-frequency shaping techniques to enable two-photon interference between photons from dissimilar sources. We match the vastly different spectral bandwidths of photons from semiconductor quantum dots and parametric down-conversion, such that both types of sources can be deployed together in quantum networks.
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.
Our project on many-particle interference takes a look at interference phenomena beyond single particles or waves. For multiple identical particles, another layer of interference arises due to their exchange symmetry. We investigate conditions for fully destructive interference theoretically as well as experimentally via multi-photon states from nonlinear crystals or quantum dots.
Our SFB project P14 - Integrated Quantum Photonics targets optical quantum information processing on a highly integrated III-V semiconductor platform. This platform is extremely versatile, because it goes beyond just passive elements but hosts single photon and photon pair sources based on quantum dots and on spontaneous parametric down-conversion.
Concluded projects can be found here.
collaborations
Buchleitner Andreas, University of Freiburg, Germany
Höfling Sven & Tobias Huber, University of Wuerzburg, Germany
Nolte Stefan, Institute of Applied Physics, Jena, Germany
Heindel Tobias, Technical University of Berlin, Germany
Walther Philipp, University of Vienna, Austria
Hall Kimberley, Dalhousie University, Canada
Dalacu Dan, National Research Council, Canada
Imamoglu Atac, ETH Zuerich, Switzerland
Jenewein Thomas, IQC and University of Waterloo, Ontario, Canada
Predojevic Ana, Stockholm University, Sweden
Pullerits Tönu, Lund University, Sweden
Rastelli Armando, Johannes Kepler University Linz, Austria
Reitzenstein Stefan, Technical University Berlin, Germany
Szameit Alexander, University of Rostock, Germany
Norbert Keil & Moritz Kleinert, Fraunhofer HHI Berlin, Germany
publications
Please find a detailed list of all our publications here.
funding
The European Union supports our research activities related to quantum technology / quantum communications through it's Horizon 2020 research and innovation programme: Quantum Flagship.
The Austrian Science Fundfunds our work through the following projects
- SFB "Beyond-C", project "P14 - Integrated Quantum Photonics" (F 7114, together with IST Austria, University of Vienna, OEAW, Max-Planck-Institute for Quantum Optics in Garching, Germany)
- D-A-CH project "On-chip microlaser driven sources of indistinguishable photons for quantum networks" (I-5061, together with Tobias Huber, University of Würzburg and Stephan Reizenstein, University of Berlin)
- IGUANA - "Integrated Quantum Rangefinding" (Q 3)
- AEQuDot - "Advanced Entanglement from Quantum Dots" (I 4380, together with Doris Reiter, TU Dortmund and Armando Rastelli, University of Linz)
- DarkEneT - "Engineering Dark modes for Energy Trapping" (TAI 556 1000 Ideas Program)
- Project "Multiphoton Experiments with Semiconductor Quantum Dots", (FG 5)
- Doctoral Program "Atoms, Light and Molecules" (W-1259, Speaker: R. Wester)
