NEWS
23.05.2023The IOP–Humboldt Postdoctoral Fellowship in PhysicsNominations are open for postdoctoral fellowships between two cities, Berlin and Beijing, as part of a joint physics program between the Integrative Research Institute for the Sciences (IRIS Adlershof) of Humboldt-Universität zu Berlin (HU Berlin) and the Institute of Physics, Chinese Academy of Sciences, (IOP) Beijing. FELLOWSHIP PROGRAMEstablished in 2020, the prestigious two-year research fellowships are intended for exceptional early-career scientists, in preparation for an independent career in research at the frontier of condensed matter physics, quantum materials or device physics. Successful candidates will spend one year in Berlin and one in Beijing at the research groups of their choice, supported by up to 4,500 EUR/month. The selected fellows are expected to be appointed in 2023 and 2024. A first networking event is scheduled in Berlin. Fellows will work at the Campus Adlershof of HU Berlin and the IOP Zhongguancun Beijing Campus. The fellows have the possibility to visit and interact with associated Partners at the Max Born Institute, the Helmholtz-Zentrum Berlin and its Electron Storage Ring BESSY II, the Leibniz-Institut für Kristallzüchtung or the Fritz-Haber Institute of the Max Planck Society.The prestigious two-year research fellowships are intended for exceptional early-career scientists, in preparation for an independent career in research at the frontier of condensed matter physics, quantum materials or device physics. Successful candidates will spend one year in Berlin and one in Beijing at the research groups of their choice, supported by up to 4,500 EUR/month. The selected fellows will be appointed from August 2022 onwards. A first networking event is programmed in Berlin. Fellows will work at the Campus Adlershof of HU Berlin and the IOP Zhongcuancun Beijing Campus. The fellows have the possibility to visit and interact with associated Partners at the Max Born Institute, the Helmholtz-Zentrum Berlin and its Electron Storage Ring BESSY II, the Freie Universität Berlin, at the Leibniz-Institut für Kristallzüchtung or the Fritz-Haber Institute of the Max Planck Society. A full list of participating groups can be found at HU Physics and the IOP website. Exemplary fields and participating groups includeCondensed Matter Theory Prof. Claudia Draxl, Prof. Sheng Meng, Prof. Hongming Weng, Prof. Chen Fang, Prof. Xinguo Ren, Prof. Jiangping Hu, Prof. Zhong Fang, Prof. Tao Xiang, Prof. Matthias Scheffler Ultrafast Laser Spectroscopy Photoemission Spectroscopy and Surface Science Optoelectronic Devices and Quantum Transport Scanning Probe Microscopy Quantum Information Electron Microscopy
Commitment to a one-year research stay at IOP followed by a further year at HU Berlin. Special travel preferences will be considered. A PhD degree in physics, chemistry, mathematics, or materials, obtained no more than five years prior to the application deadline. Previous international experience, such as conference talks and research abroad.
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Prof. Dr. rer. nat. Dr. h.c. Joachim Sauer, who is a Senior Researcher at the Department of Chemistry at Humboldt-Universität zu Berlin, has been appointed a member of the American Academy of Arts and Sciences based on his research activities at the department, in two Collaborative Research Centres at Humboldt-Universität and in the Cluster of Excellence UNICAT. Admission to the Academy will take place in a formal ceremony on 30 September 2023 in Cambridge, Massachusetts. |
| Illustration: Defect centres in diamond nanostructures can be used as quantum bits. The quantum information can be stored in individual photons via quantumoperation and than be transmitted in optical fibres in the future quantum internet. |
Diamond material is of great importance for future technologies such as the quantum internet. Special defect centers can be used as quantum bits (qubits) and emit single light particles that are referred to as single photons. To enable data transmission with feasible communication rates over long distances in a quantum network, all photons must be collected in optical fibers and transmitted without being lost. It must also be ensured that these photons all have the same color, i.e., the same frequency. Fulfilling these requirements has been impossible until now.
Researchers in the "Integrated Quantum Photonics" group led by Prof. Dr. Tim Schröder, member of IRIS Adlershof, have succeeded for the first time worldwide in generating and detecting photons with stable photon frequencies emitted from quantum light sources, or, more precisely, from nitrogen-vacancy defect centers in diamond nanostructures. This was enabled by carefully choosing the diamond material, sophisticated nanofabrication methods carried out at the Joint Lab Diamond Nanophotonics of the Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, and specific experimental control protocols. By combining these methods, the noise of the electrons, which previously disturbed data transmission, can be significantly reduced, and the photons are emitted at a stable (communication) frequency.
In addition, the Berlin researchers show that the current communication rates between spatially separated quantum systems can prospectively be increased more than 1000-fold with the help of the developed methods—an important step closer to a future quantum internet.
The scientists have integrated individual qubits into optimized diamond nanostructures. These structures are 1000 times thinner than a human hair and make it possible to transfer emitted photons in a directed manner into glass fibers. However, during the fabrication of the nanostructures, the material surface is damaged at the atomic level, and free electrons create uncontrollable noise for the generated light particles. Noise, comparable to an unstable radio frequency, causes fluctuations in the photon frequency, preventing successful quantum operations such as entanglement.
A special feature of the diamond material used is its relatively high density of nitrogen impurity atoms in the crystal lattice. These possibly shield the quantum light source from electron noise at the surface of the nanostructure. "However, the exact physical processes need to be studied in more detail in the future," explains Laura Orphal-Kobin, representative of the junior scientist at IRIS Adlershof, who investigates quantum systems together with Prof. Dr. Tim Schröder. The conclusions drawn from the experimental observations are supported by statistical models and simulations, which Dr. Gregor Pieplow from the same research group is developing and implementing together with the experimental physicists.
L. Orphal-Kobin, K. Unterguggenberger, T. Pregnolato, N. Kemf, M. Matalla, R.-S. Unger, I. Ostermay, G. Pieplow, and T. Schröder
Physical Review X (2023)
Contact:
Laura Orphal-Kobin, phone: +49 30 2093 82146, mail: orphalphysik.hu-berlin.de
Prof. Dr. Tim Schröder, phone: +49 30 2093 82140, mail: tim.schroederphysik-hu-berlin.de
Humboldt-Universität zu Berlin, Department of Physics and IRIS Adlershof, Integrated Quantum Photonics Group & Joint Lab Diamond Nanophotonics, Ferdinand-Braun-Institut