Faculty of Applied Sciences
10 October 2019
Pascale Daran: "’Involve me and I learn’ is my teaching motto”Interactive lecturing is a priority of TNW Teacher of The Year Pascale Daran (LST). She coordinates the bachelor's practical course in Biotechnology Basic Techniques and discusses scientific literature with master's students in the Metabolic Reprogramming course. "I like this form of education, students see that I do this from the heart. For me, a lecture is a success if the discussion is so animated that I could just disappear."
08 October 2019
New horizons for connecting future quantum computers into a quantum networkResearchers, led by Delft University of Technology, have made two steps in the conversion of quantum states between signals in the microwave and optical domains. This is of great interest for connecting future superconducting quantum computers into a global quantum network . This week they report on their findings in Nature Physics and in Physical Review Letters . Quantum network Conversion between signals in the microwave and optical domains is of great interest, particularly for connecting future superconducting quantum computers into a global quantum network. Many leading eﬀorts in quantum technologies, including superconducting qubits and quantum dots, share quantum information through photons in the microwave regime. While this allows for an impressive degree of quantum control, it also limits the distance the information can realistically travel before being lost to a mere few centimeters. At the same time, the ﬁeld of optical quantum communication has already seen demonstrations over distance scales capable of providing real-world applications. By transmitting information in the optical telecom band, ﬁber-based quantum networks over tens or even hundreds of kilometers can be envisaged. ‘In order to connect several quantum computing nodes over large distances into a quantum internet, it is therefore vital to be able to convert quantum information from the microwave to the optical domain, and back’, says Prof. Simon Groeblacher of Delft University of Technology, whose group was leading both studies. ‘This will not only be extremely interesting for quantum applications, but also for highly efficient, low-noise conversion between classical optical and electrical signals’. Ground state Several promising approaches have been taken to realize a microwave to optics converter, for instance by trying to couple the signals through a mechanical system (oscillator). But they have so far all operated with a substantial thermal noise background. ‘We have overcome this limitation and demonstrated coherent conversion between GHz microwave signals and the optical telecom band with minimal thermal background noise’, Moritz Forsch, one of the two lead authors on the publications, explains. To achieve this, it was necessary to cool the mechanical oscillator into the quantum ground state of motion. The low thermal occupation forms the basis for quantum control over mechanical states. Rob Stockill, the other lead author, continues: ‘We use an integrated, on-chip electro-opto-mechanical device that couples surface acoustic waves driven by a resonant microwave signal to an optomechanical crystal. We initialize the mechanical mode in its quantum ground state, which allows us to perform the transduction process with minimal added thermal noise, while maintaining that microwave photons mapped into the mechanical resonator are eﬀectively upconverted to the optical domain.’ Piezoelectric materials Groeblacher’s team has recently made another step forward in this field, by focusing on the use of novel piezoelectric materials. These materials, in which electrical fields are produced due to mechanical stress, could be of great interest for the transduction of quantum information between different carriers. The electromechanical coupling in principle allows for transduction of a quantum state between the microwave and optical frequency domains in this material. A promising approach is therefore to build integrated piezoelectric opto-mechanical devices, that are then coupled to microwave circuits. ‘We have designed and characterized such a piezoelectric optomechanical device fabricated from gallium phosphide, in which a 2.9 GHz mechanical mode is coupled to a high quality factor optical resonator in the telecom band. The large electronic bandgap and the resulting low optical absorption of this new material, on par with devices fabricated from silicon, allows us to demonstrate quantum behavior of the structure’, says Prof. Groeblacher. Next step The device fabricated from gallium phosphide (GaP) far surpasses current achievements in GaAs or other piezoelectric materials typically used in similar approaches. The next step for the researchers is to build upon the successful operation of the GaP device in this parameter regime and further investigate the use of this exciting material. Given the wide electronic bandgap and piezoelectric properties of GaP, these research results open the door for novel quantum experiments as well as the potential for using such devices for microwave-to-optics conversion of single photons. The publication in Nature Physics was a collaboration between Delft University of Technology, the University of Vienna, Eindhoven University of Technology and NIST. The publication in Physical Review Letters was a collaboration between Delft University of Technology, Universit é Paris-Sud, Universit é Paris-Saclay and Universit é de Paris. *** References M. Forsch*, R. Stockill*, A. Wallucks, I. Marinković, C. Gärtner, R. A. Norte, F. van Otten, A. Fiore, K. Srinivasan, and S. Gröblacher, Microwave-to-optics conversion using a mechanical oscillator in its quantum groundstate, Nature Phys. (2019) https://www.nature.com/articles/s41567-019-0673-7 R. Stockill*, M. Forsch*, G. Beaudoin, K. Pantzas, I. Sagnes, R. Braive, and S. Gröblacher, Gallium phosphide as a piezoelectric platform for quantum optomechanics, Phys. Rev. Lett. accepted (2019) https://journals.aps.org/prl/accepted/3b07bY50T8213b7878400c32cfb0a83f3db60bccc Freely available pre-print: https://arxiv.org/abs/1909.07850 More information For more information please contact: Dr. Simon Gröblacher Department of Quantum Nanoscience Kavli Institute of Nanoscience Delft University of Technology Lorentzweg 1, 2628 CJ Delft T +31 15 2786124 firstname.lastname@example.org Artists impression of a microwave-opto-acoustic transducer. The electrodes (top left, gold) launch propagating acoustic waves that can be measured optically in a photonic crystal nanobeam (bottom right). Such a device is used to demonstrate a coherent conversion process between a microwave GHz and an optical telecom signal, at the quantum noise limit. (Credits: Moritz Forsch. Kavli Institute of Nanoscience, Delft University of Technology.)
26 September 2019
Launch of new raw material from wastewater: KaumeraA sustainable alternative to chemicals in seeds, granular fertilizer, concrete and paint? On 2 October 2019, water boards, science (TU Delft) and industry will present a new raw material extracted from wastewater: Kaumera Nereda® Gum. This raw material is a sustainable alternative to chemical raw materials and can be used as a smart coating for seeds and granular fertilizer, as a glue and binder and in many other ways.
26 September 2019
Martin Bruggink: "Teaching better by connecting to the student's perspective"Teacher of the Year Martin Bruggink (SEC) is all about education. "How do you ensure that people really learn something, that's the question teacher training revolves around. I teach the TU students I am in charge of to pass on knowledge to secondary school students as well as possible. I am pleased with the appreciation for education expressed in this election, which clearly shows that you can excel in this area as well."
Life from the lab
Scientists at TU Delft want to make a synthetic cell from separate biological building blocks.
Crafting matter atom by atom
Over the past twenty years, the scale of data storage decreased at an astonishing rate. With society currently creating more than a billion gigabytes of data every day, further decrease of data storage area is becoming increasingly relevant. Together with his team, however, Prof. Sander Otte from Delft University of Technology found the ultimate solution.
Tinkering under the bonnet of life
CRISPR-Cas9, the technique scientists use to very precisely edit DNA, is receiving global attention. And rightly so, because this technology has far-reaching consequences. A longer life in good health? The end of genetic disorders? Crops that are able to survive in the harshest conditions? CRISPR-Cas9 brings all of this and more within our grasp. The research group of Dr Stan Brouns at the department of Bionanoscience is conducting fundamental research into how CRISPR systems function. What is his take on the forthcoming revolution?