Projects

Filter
Name
Funded by
Active/Inactive
Name
Funded by
[all]
[none]
Active/Inactive
17 Results
Munich Center for Quantum Science and Technology (MCQST)
Funded by German Research Foundation (DFG)
The cluster of excellence Munich Center for Quantum Science and Technology (MCQST) comprises seven research units within disciplines such as physics, mathematics, computer science, electrical engineering, material science, and chemistry, covering all areas of Quantum Science and Technology (QST) from basic research to applications. Its main goal is to build a world-leading center in QST, with a multidisciplinary profile, addressing important scientific and technological questions. It links groundbreaking research with industrial partners, creating a unique environment for Quantum Science and Technology via carefully designed structural measures that will transform the existing scientific and technological environment.

Quantum Mechanics and Information Science have revolutionized our modern world beyond imagination. Whilst quantum mechanics forms the basis for our understanding of the microscopic world, information science is the basic building block for information processing and communication in our digital age. Today we are witnessing a scientific and technological revolution in which Information Science and Quantum Mechanics no longer stand as separate entities, but have rather been united in the common language of Quantum Information Science. First developed to describe the working principles of future Quantum Computers, Quantum Information Science has emerged as an even more powerful description of our physical world, with wide ranging relevance, directly linking fields such as quantum materials and quantum chemistry to seemingly disparate fields such as the cosmology of black holes. At the core of this description is the notion of entanglement, an essential feature without any classical analogue that is responsible for a plethora of astonishing phenomena and applications of Quantum Physics.

These dramatic developments have led to the new combined research field of Quantum Science and Technology (QST), in which these diverse topics, their interconnection as well as their consequences for practical applications are being explored. QST unites multidisciplinary research across physics, mathematics, computer science, electrical engineering, materials science, chemistry, and recently, even cosmology and high energy physics.The core goal of the Munich Center for Quantum Science and Technology (MCQST) is to discover and understand the novel and unifying concepts in the interdisciplinary research fields of QST and to make them tangible and practical, to develop the extraordinary applications within reach by building next-generation quantum devices.

At a fundamental science level, this includes the comprehensive understanding and control of entanglement in quantum many-body systems spanning different time, length and energy scales, through novel theoretical and experimental approaches in quantum information science. Applications for Quantum Devices and Materials to be developed at MCQST range from inherently secure communication and processing of information to ultrasensitive sensors and transducers for precision metrology.Munich is in a unique position to form such a world-leading research center in QST due to its longstanding experience, broad and proven interdisciplinary expertise, and outstanding excellence of the participating senior and junior researchers in all core fields of QST. Developing education and support for junior researchers in QST as well as advancing the strengths of Munich research structures within MCQST will ensure long-term and high-impact research as well as an ideal entry point for industry in this increasingly important field. It will allow Munich to achieve an outstanding visibility and assume a leading position in QST research.

Publications
Qi-Ming Chen, Florian Fesquet, Kedar E. Honasoge, Fabian Kronowetter, Yuki Nojiri, Michael Renger, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | arXiv:2107.01842  (2021)
Thomas Luschmann, Philip Schmidt, Frank Deppe, Achim Marx, Alvaro Sanchez, Rudolf Gross, Hans Huebl
Research Article | arXiv:2104.10577  (2021)
Tobias Wimmer, Janine Gückelhorn, Sebastian Wimmer, Sergiy Mankovsky, Hubert Ebert, Matthias Opel, Stephan Geprägs, Rudolf Gross, Hans Huebl, Matthias Althammer
Research Article | arXiv:2103.12697  (2021)
G. Terrasanta, M. Müller, T. Sommer, S. Geprägs, R. Gross, M. Althammer, M. Poot
Research Article | Materials for Quantum Technology 1, 021002  (2021)
K. G. Fedorov, M. Renger, S. Pogorzalek, R. Di Candia, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe
Research Article | arXiv:2103.04155  (2021)
Paul Rosenberger, Matthias Opel, Stephan Geprägs, Hans Huebl, Rudolf Gross, Martina Müller, Matthias Althammer
Research Article | Applied Physics Letters 118, 192401  (2021)
Lukas Liensberger, Franz X. Haslbeck, Andreas Bauer, Helmuth Berger, Rudolf Gross, Hans Huebl, Christian Pfleiderer, Mathias Weiler
Research Article | arXiv:2102.11713  (2021)
Luis Flacke, Valentin Ahrens, Simon Mendisch, Lukas Körber, Tobias Böttcher, Elisabeth Meidinger, Misbah Yaqoob, Manuel Müller, Lukas Liensberger, Attila Kákay, Markus Becherer, Philipp Pirro, Matthias Althammer, Stephan Geprägs, Hans Huebl, Rudolf Gross, Mathias Weiler
Research Article | arXiv:2102.11117  (2021)
Manuel Müller, Raphael Hoepfl, Lukas Liensberger, Stephan Geprägs, Hans Huebl, Mathias Weiler, Rudolf Gross, Matthias Althammer
Research Article | arXiv:2102.09018  (2021)
Manuel Müller, Lukas Liensberger, Luis Flacke, Hans Huebl, Akashdeep Kamra, Wolfgang Belzig, Rudolf Gross, Mathias Weiler, Matthias Althammer
Research Article | Physical Review Letters 126, 087201  (2021)
Schwienbacher, Daniel
PHD Thesis | Technische Universität München  (2021)
Jasmin Graf, Sanchar Sharma, Hans Huebl, and Silvia Viola Kusminskiy
Research Article | Physical Review Research 3, 013277  (2021)
R. Ramazashvili, P. D. Grigoriev, T. Helm, F. Kollmannsberger, M. Kunz, W. Biberacher, E. Kampert, H. Fujiwara, A. Erb, J. Wosnitza, R. Gross & M. V. Kartsovnik
Research Article | npj Quantum Materials 6, 11  (2021)
Rudolf Gross
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 14-19  (2021)
Frank Deppe, Kirill G. Fedorov, Achim Marx
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 36-38  (2021)
Hans Hübl
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 32-35  (2021)
Stefan Filipp
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 20-23  (2021)
Ei Shigematsu, Lukas Liensberger, Mathias Weiler, Ryo Ohshima, Yuichiro Ando, Teruya Shinjo, Hans Huebl, and Masashi Shiraishi
Research Article | Physical Review B 103, 094430  (2021)
Daniel Schwienbacher, Thomas Luschmann, Rudolf Gross, Hans Huebl
Research Article | arXiv:2011.08080  (2020)
M. Renger, S. Pogorzalek, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe, K. G. Fedorov
Research Article | arXiv:2011.00914  (2020)
Stephan Geprägs, Christoph Klewe, Sibylle Meyer, Dominik Graulich, Felix Schade, Marc Schneider, Sonia Francoual, Stephen P. Collins, Katharina Ollefs, Fabrice Wilhelm, Andrei Rogalev, Yves Joly, Sebastian T.B. Goennenwein, Matthias Opel, Timo Kuschel, Rudolf Gross
Research Article | Physical Review B 102, 214438  (2020)
Stephan Geprägs, Björn Erik Skovdal, Monika Scheufele, Matthias Opel, Didier Wermeille, Paul Thompson, Alessandro Bombardi, Virginie Simonet, Stéphane Grenier, Pascal Lejay, Gilbert Andre Chahine, Diana Quintero Castro, Rudolf Gross, Dan Mannix
Research Article | Physical Review B 102, 214402  (2020)
Tobias Wimmer, Akashdeep Kamra, Janine Gückelhorn, Matthias Opel, Stephan Geprägs, Rudolf Gross, Hans Huebl, Matthias Althammer
Research Article | Physical Review Letters 125, 247204  (2020)
Philip Schmidt, Mohammad T. Amawi, Stefan Pogorzalek, Frank Deppe, Achim Marx, Rudolf Gross, Hans Huebl
Research Article | Communications Physics 3, 233  (2020)
Akashdeep Kamra, Tobias Wimmer, Hans Huebl, and Matthias Althammer
Research Article | Physical Review B 102, 174445  (2020)
Stefan Weichselbaumer, Christoph W. Zollitsch, Martin S. Brandt, Rudolf Gross, Hans Huebl
Research Article | Physical Review Letters 125, 137701  (2020)
Johanna Fischer, Matthias Althammer, Nynke Vlietstra, Hans Huebl, Sebastian T.B. Goennenwein, Rudolf Gross, Stephan Geprägs, Matthias Opel
Research Article | Physical Review Applied 13, 014019  (2020)
Tobias Hula, Katrin Schultheiss, Aleksandr Buzdakov, Lukas Körber, Mauricio Bejarano, Luis Flacke, Lukas Liensberger, Mathias Weiler, Justin M. Shaw, Hans T. Nembach, Jürgen Fassbender, and Helmut Schultheiss
Research Article | Applied Physics Letters 117, 042404  (2020)
J. Gückelhorn, T. Wimmer, S. Geprägs, H. Huebl, R. Gross, and M. Althammer
Research Article | Applied Physics Letters 117, 182401  (2020)
Pogorzalek, Stefan
PHD Thesis | Technische Universität München  (2020)
Paul G. Evans, Samuel D. Marks, Stephan Geprägs, Maxim Dietlein, Yves Joly, Minyi Dai, Jiamian Hu, Laurence Bouchenoire, Paul B. J. Thompson, Tobias U. Schülli, Marie-Ingrid Richard, Rudolf Gross, Dina Carbone, Danny Mannix
Research Article | Science Advances 6, eaba9351  (2020)
Weichselbaumer, Stefan
PHD Thesis | Technische Universität München  (2020)
Stephan Geprägs, Matthias Opel, Johanna Fischer, Olena Gomonay, Philipp Schwenke, Matthias Althammer, Hans Huebl, Rudolf Gross
Research Article | Journal of Applied Physics 127, 243902  (2020)
Qi-Ming Chen, Frank Deppe, Re-Bing Wu, Luyan Sun, Yu-xi Liu, Yuki Nojiri, Stefan Pogorzalek, Michael Renger, Matti Partanen, Kirill G. Fedorov, Achim Marx, Rudolf Gross
Research Article | arXiv:1912.09861  (2019)
Tobias Wimmer, Birte Coester, Stephan Geprägs, Rudolf Gross, Sebastian T. B. Goennenwein, Hans Huebl, Matthias Althammer
Research Article | Applied Physics Letters 115, 092404  (2019)
Lukas Liensberger, Akashdeep Kamra, Hannes Maier-Flaig, Stephan Geprägs, Andreas Erb, Sebastian T. B. Goennenwein, Rudolf Gross, Wolfgang Belzig, Hans Huebl, Mathias Weiler
Research Article | Physical Review Letters 123, 117204  (2019)
Luis Flacke, Lukas Liensberger, Matthias Althammer, Hans Huebl, Stephan Geprägs, Katrin Schultheiss, Aleksandr Buzdakov, Tobias Hula, Helmut Schultheiss, Eric R. J. Edwards, Hans T. Nembach, Justin M. Shaw, Rudolf Gross, Mathias Weiler
Research Article | Applied Physics Letters 115, 122402  (2019)
Daniel Schwienbacher, Matthias Pernpeintner, Lukas Liensberger, Eric R. J. Edwards, Hans T. Nembach, Justin M. Shaw, Mathias Weiler, Rudolf Gross, Hans Huebl
Research Article | Journal of Applied Physics 126, 103902  (2019)
S. Pogorzalek, K. G. Fedorov, M. Xu, A. Parra-Rodriguez, M. Sanz, M. Fischer, E. Xie, K. Inomata, Y. Nakamura, E. Solano, A. Marx, F. Deppe, R. Gross
Research Article | Nature Communications 10, 2604  (2019)
Tobias Wimmer, Matthias Althammer, Lukas Liensberger, Nynke Vlietstra, Stephan Geprägs, Mathias Weiler, Rudolf Gross, Hans Huebl
Research Article | Physical Review Letters 123, 257201  (2019)
Lukas Liensberger, Luis Flacke, David Rogerson, Matthias Althammer, Rudolf Gross, Mathias Weiler
Research Article | IEEE Magnetics Letters 10, 5503905  (2019)
Mikel Sanz, Kirill G. Fedorov, Frank Deppe, Enrique Solano
Research Article | 2018 IEEE Conference on Antenna Measurements Applications (CAMA), Västerås , pp. 1-4  (2018)
Edwar Xie, Frank Deppe, Michael Renger, Daniel Repp, Peter Eder, Michael Fischer, Jan Goetz, Stefan Pogorzalek, Kirill G. Fedorov, Achim Marx, and Rudolf Gross
Research Article | Applied Physics Letters 112, 202601  (2018)
Jan Goetz, Frank Deppe, Kirill G. Fedorov, Peter Eder, Michael Fischer, Stefan Pogorzalek, Edwar Xie, Achim Marx, Rudolf Gross
Research Article | Physical Review Letters 121, 060503  (2018)
P. Eder, T. Ramos, J. Goetz, M. Fischer, S. Pogorzalek, J. Puertas Martínez, E.P. Menzel, F. Loacker, E. Xie, J.J. Garcia-Ripoll, K.G. Fedorov, A. Marx, F. Deppe, R. Gross
Research Article | Supercond. Sci. Technol. 31, 115002  (2018)
Philip Schmidt, Daniel Schwienbacher, Matthias Pernpeintner, Friedrich Wulschner, Frank Deppe, Achim Marx, Rudolf Gross, Hans Huebl
Research Article | Appl. Phys. Lett. 113, 152601  (2018)
Grant No.
EXC-2111 – 390814868
Funded by
German Research Foundation (DFG)
Funding program
Excellence Strategy
Quantum Microwave Communication and Sensing (QMiCS)
Funded by European Union (EU)
Welcome to QMiCS – a European Quantum Flagship project -- QMiCS sets up a quantum microwave local area network cable over a distance of several meters. We will use this architecture to implement quantum communication protocols such as teleportation between two superconducting quantum nodes. Since our approach does not require any of the notoriously loss‑prone frequency conversion techniques, our platform will be highly beneficial for distributed quantum computing. In addition, we take first steps towards the ambitious goal of radar-style quantum sensing with microwaves. Major milestones here are the implementation of microwave single photon detectors and the development of a roadmap towards commercial applications in later phases of the Flagship.

The mission of QMiCS is to combine European expertise and lead the efforts in developing novel components, experimental techniques, and theory models building on the quantum properties of continuous-variable propagating microwaves.

QMiCS’ long-term visions are (i) distributed quantum computing & communication via microwave quantum local area networks (QLANs) and (ii) sensing applications based on the illumination of an object with quantum microwaves (quantum radar). With respect to key quantum computing platforms (superconducting circuits, NV centers, quantum dots), microwaves intrinsically allow for zero frequency conversion loss since they are the natural frequency scale. They can be distributed via superconducting cables with surprisingly little losses, eventually allowing for quantum communication and cryptography applications.

Radar works at gigahertz frequencies because of the atmospheric transparency windows anyways.

Scientifically, QMiCS targets a QLAN demonstration via quantum teleportation, a quantum advantage in microwave illumination, and a roadmap to real-life applications for the second/third phase of the QT Flagship.

Beneath these three grand goals lies a strong component of disruptive enabling technology provided by two full and one external industry partner: the development of a microwave QLAN cable connecting the millikevin stages of two dilution refrigerators, improved cryogenic semiconductor amplifiers, and packaged pre-quantum ultrasensitive microwave detectors.

The resulting “enabling” commercial products are beneficial for quantum technologies at microwave frequencies in general.

Finally, QMiCS fosters awareness in industry about the revolutionary business potential of quantum microwave technologies, especially via the advisory third parties “Airbus Defence and Space Ltd” and “Cisco Systems GmbH”. In this way, QMiCS helps placing Europe at the forefront of the second quantum revolution and kick-starting a competitive European quantum industry.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant No 820505.

Publications
Qi-Ming Chen, Florian Fesquet, Kedar E. Honasoge, Fabian Kronowetter, Yuki Nojiri, Michael Renger, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | arXiv:2107.01842  (2021)
K. G. Fedorov, M. Renger, S. Pogorzalek, R. Di Candia, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe
Research Article | arXiv:2103.04155  (2021)
Michael Fischer, Qi-Ming Chen, Christian Besson, Peter Eder, Jan Goetz, Stefan Pogorzalek, Michael Renger, Edwar Xie, Michael J. Hartmann, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | Physical Review B 103, 094515  (2021)
Frank Deppe, Kirill G. Fedorov, Achim Marx
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 36-38  (2021)
M. Renger, S. Pogorzalek, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe, K. G. Fedorov
Research Article | arXiv:2011.00914  (2020)
Pogorzalek, Stefan
PHD Thesis | Technische Universität München  (2020)
Qi-Ming Chen, Frank Deppe, Re-Bing Wu, Luyan Sun, Yu-xi Liu, Yuki Nojiri, Stefan Pogorzalek, Michael Renger, Matti Partanen, Kirill G. Fedorov, Achim Marx, Rudolf Gross
Research Article | arXiv:1912.09861  (2019)
S. Pogorzalek, K. G. Fedorov, M. Xu, A. Parra-Rodriguez, M. Sanz, M. Fischer, E. Xie, K. Inomata, Y. Nakamura, E. Solano, A. Marx, F. Deppe, R. Gross
Research Article | Nature Communications 10, 2604  (2019)
Mikel Sanz, Kirill G. Fedorov, Frank Deppe, Enrique Solano
Research Article | 2018 IEEE Conference on Antenna Measurements Applications (CAMA), Västerås , pp. 1-4  (2018)
Edwar Xie, Frank Deppe, Michael Renger, Daniel Repp, Peter Eder, Michael Fischer, Jan Goetz, Stefan Pogorzalek, Kirill G. Fedorov, Achim Marx, and Rudolf Gross
Research Article | Applied Physics Letters 112, 202601  (2018)
P. Eder, T. Ramos, J. Goetz, M. Fischer, S. Pogorzalek, J. Puertas Martínez, E.P. Menzel, F. Loacker, E. Xie, J.J. Garcia-Ripoll, K.G. Fedorov, A. Marx, F. Deppe, R. Gross
Research Article | Supercond. Sci. Technol. 31, 115002  (2018)
Coordinator

Frank Deppe

Grant No.
H2020.820505
Funded by
European Union (EU)
Funding program
Quantum Flagship
Parametric Multi-Qubit Gates (QUSTEC)
Funded by European Union (EU)
This project explores the potential of multi-qubit gates for quantum computing on a superconducting qubit platform. The main goal is to develop superconducting architectures and control methods to efficiently generate multi-qubit states going beyond the current paradigm of decomposing all state manipulations into single and two-qubit gates.

We design and realize parametric couplers connecting multiple superconducting qubits and investigate multi-qubit operations that allow us to entangle multiple qubits at the same time. We explore multi-qubit entangling interactions and evaluate the maximally possible number of qubits coupled to a single coupler. We aim to address the question if there is an advantage in using multi-qubit gates over traditional two-qubit gates in practical experiments. The devices and methods developed in this project will enhance the scalability of superconducting qubit platforms and the efficiency of quantum algorithms.

Contact
Coordinator

Prof. Guido Pupillo, Univ. Strasbourg

Grant No.
H2020.Cofund.847471
Funded by
European Union (EU)
Funding program
Marie Skłodowska-Curie Action (MSCA), Quantum Science and Technologies at the European Campus (QUSTEC)
Quantum Radar Team (QUARATE)
Funded by Federal Ministry of Education and Research (BMBF)
Klassische Radartechnologien (in Luft‐ und Raumfahrt, Messtechnik oder autonomes Fahren) stoßen bereits heute an ihre physikalischen Grenzen, hauptsächlich limitiert durch das Rauschen in der Umgebung. Ab einem gewissen Signal‐zu‐Rausch‐Verhältnis (SRV) ist eine Informationsgewinnung mittels herkömmlicher klassischer Mikrowellensignale nicht mehr möglich. Durch die Verwendung von Quantenmikrowellen und die daraus resultierenden neuen Korrelationsmöglichkeiten kann man die Informationsgewinnung jedoch weiter verbessern. Dieser sogenannte Quantenvorteil kann signifikant zur Reichweitensteigerung oder zur Reduktion der Signalleistung beitragen. Eine alternative Technologie zur grundsätzlichen Steigerung des SRV ist derzeit nicht bekannt.

Zunächst soll der Quantenvorteil unter Laborbedingungen (Temperaturen im Bereich von milliKelvin, Vakuum) nachgewiesen werden. Anschließend müssen geeignete Technologien entwickelt werden, um die unter milliKelvin‐Temperaturen erzeugten Quantenmikrowellen auch über Antennen im ungekühlten Freiraum abstrahlen und wieder detektieren zu können. Hierbei gilt ein besonderes Augenmerk der anspruchsvollen Signalverarbeitung. Diese muss auch theoretische Untersuchungen von Faktoren mit technischer Relevanz, z.B. Dekohärenz, beinhalten. Insgesamt ergibt sich daraus eine Roadmap hin zu feldtauglichen Implementierungen, und somit zur kommerziellen Verwertung.

Das Vorhaben bezieht sich auf bereits vorhandene wissenschaftliche Grundlagen. Die Innovation steckt daher vielmehr im Forschungs‐ und‐ Entwicklungsprozess, bei dem Systementwicklungsaufgaben wie Skalierung  und die Bewältigung technologischer Herausforderungen im Vordergrund stehen. Neben dem Know-How zum Quantenradar werden auch ganz allgemein Quantentechnologien mit supraleitenden Schaltkreisen auch in Deutschland nachhaltig etabliert.

Publications
Qi-Ming Chen, Florian Fesquet, Kedar E. Honasoge, Fabian Kronowetter, Yuki Nojiri, Michael Renger, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | arXiv:2107.01842  (2021)
K. G. Fedorov, M. Renger, S. Pogorzalek, R. Di Candia, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe
Research Article | arXiv:2103.04155  (2021)
Coordinator

Dr.-Ing. Baris Güzelarslan
Rohde & Schwarz GmbH & Co. KG
München

Grant No.
13N15380
Funded by
Federal Ministry of Education and Research (BMBF)
Funding program
Anwendungsbezogene Forschung in der Quantensensorik, -metrologie sowie -bildgebung
German Quantum Computer based on Superconducting Qubits (GeQCoS)
Funded by Federal Ministry of Education and Research (BMBF)
Building quantum processor with novel properties based on superconducting qubits - this is the aim of the four year project GeQCoS ('German Quantum Computer based on Superconducting Qubits') funded by the BMBF. In this joint project, Germany's leading scientists in the field of superconducting quantum circuits have teamed up to develop innovative concepts for the construction of an improved quantum processor.

They aim to realize a quantum processor with improved quality based on new materials and manufacturing methods by the Karlsruhe Institute of Technology (KIT), tailor-made theoretical concepts of the Friedrich-Alexander University Erlangen Nürnberg (FAU), optimized control methods of the Forschungszentrum Jülichs (FZJ) and concepts for new architectures with higher connectivity at the Walther-Meißner-Institute (WMI – Bavarian Academy of Sciences and Technical University of Munich). In order to achieve this goal, semiconductor manufacturer Infineon will develop scalable manufacturing processes, while the Fraunhofer Institute for Applied Solid State Physics (IAF) in Freiburg is promoting the development of optimized chip packages. The processor performance will eventually be demonstrated using a specifically developed quantum algorithm at the WMI.

(alter Text:) Die Realisierung von Quantencomputern und die Erzeugung der sog. Quantenbits oder kurz Qubits, die für seine Funktion notwendig sind, ist derzeit eine große Herausforderung. Die damit verbundenen Quantenzustände, sind in der Regel gegenüber äußeren Einflüssen sehr empfindlich und wenig stabil. Das ist derzeit ein großes Hindernis für die praktische Nutzung. Um hier Fortschritte zu erzielen, verfolgen die Partner des Verbundprojektes GEQCOS einen neuen Ansatz, Qubits auf der Basis supraleitender Schaltkreise zu erzeugen. Ziel ist die Realisierung eines Quantenprozessors, an dem sich die Funktionsfähigkeit des gewählten Konzepts zeigen lässt.

Für die Funktion eines Quantencomputers ist die sog. Verschränkung der Qubits notwendig. Dieser Verschränkungszustand ist nur für eine gewisse Zeit, auch Kohärenzzeit genannt, vorhanden. Nur in dieser Zeit kann der Quantencomputer rechnen. Mit dem genannten Ansatz zur Kopplung der Qubits sollen nun effiziente Operationen mit mehreren Qubits durchführbar werden. Gleichzeitig kann die Kohärenzzeit mit diesem Ansatz erhöht werden, um umfangreichere Quantenoperationen als bisher zu ermöglichen. Im Erfolgsfall ist das ein wesentlicher Schritt auf dem Weg zu praxistauglichen Quantencomputern mit einer ausreichenden Anzahl Qubits für die Lösung anwendungsbezogener Problemstellungen.

Publications
Stefan Filipp
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 20-23  (2021)
Contact
Grant No.
13N15680
Funded by
Federal Ministry of Education and Research (BMBF)
Funding program
Quantenprozessoren und Technologien für Quantencomputer
Quantum Neural Networks (Quromorphic)
Funded by European Union (EU)
Artificial neural networks, which simulate the way the human brain analyses and processes information, are used to model complex patterns and prediction problems. This approach typically involves building software rather than creating hardware that mimics neurons. The EU-funded Quromorphic project plans to implement neuromorphic computing on the hardware level. The project aims to build the first dedicated neural network computer that works on quantum mechanics principles. It will be built in hardware made of superconducting electrical circuits. Neuromorphic quantum hardware could possibly outperform classical von Neumann architectures as it can be trained on multiple batches of real-world data in parallel.

The Quromorphic project will introduce human brain inspired hardware with quantum functionalities: It will build superconducting quantum neural networks to develop dedicated, neuromorphic quantum machine learning hardware, which can, in its next generation, outperform classical von Neumann architectures. This approach will combine two cutting edge developments in information processing, machine learning and quantum computing, into a radically new technology. In contrast to established machine learning approaches that emulate neural function in software on conventional von Neumann hardware, neuromorphic quantum hardware can offer a significant advantage as it may offer the possibility to be trained on multiple batches of real world data in parallel. This feature is expected to lead to a quantum advantage. Quromorphic aims to provide proof of concept demonstrations of this new technology and a roadmap for the path towards its exploitation. To achieve this breakthrough, we will implement feed forward networks. This effort will be completed by the development of strategies for scaling the devices to the threshold where they will surpass the capabilities of existing machine learning technology and achieve quantum advantage.

Publications
M. Pechal and G. Salis and M. Ganzhorn and D. J. Egger and M. Werninghaus and S. Filipp
Research Article | arXiv:2011.08987  (2020)
Gian Salis, Nikolaj Moll, Marco Roth, Marc Ganzhorn, and Stefan Filipp
Research Article | Physical Review A 102, 062611  (2020)
M. Ganzhorn, G. Salis, D. J. Egger, A. Fuhrer, M. Mergenthaler, C. Müller, P. Müller, S. Paredes, M. Pechal, M. Werninghaus, and S. Filipp
Research Article | Physical Review Research 2, 033447  (2020)
Marek Pechal and Gian Salis and Marc Ganzhorn and Daniel J. Egger and Max Werninghaus and Stefan Filipp
Research Article | arXiv:2011.08987
Contact
Coordinator

Michael Hartmann (Univ. Nürnberg-Erlangen)

Grant No.
H2020.828826
Funded by
European Union (EU)
Funding program
Horizon 2020, Future and Emerging Technologies (FET) Open
Quantum Optimal Control (QuSCo)
Funded by European Union (EU)
The primary focus of this project will be on the design, optimal characterization and control of multi-qubit superconducting devices based on transmon qubits in a circuit QED architecture.

We will use measurement in a closed-loop way to optimize the tune-up of the system to obtain high-fidelity quantum gates. The project also addresses the question how to tailor control and measurements of a complex multi-qubit quantum processor in order to obtain targeted information in the most efficient and robust way. We will develop the tools to make best use of the retrievable information in our measurements, including statistical accuracies, backgrounds and imperfections, to find an optimal model of the system by comparing experimentally measured results with numerical/analytical predictions. The project is part of the EU training network QuSCo in which we are closely collaborating with the group of Frank Wilhelm-Mauch.

Publications
Max Werninghaus and Daniel Egger and Stefan Filipp
Research Article | Physical Review X Quantum 2, 020324  (2021)
Nicolas Wittler and Federico Roy and Kevin Pack and Max Werninghaus and Anurag Saha Roy and Daniel J. Egger and Stefan Filipp and Frank K. Wilhelm and Shai Machnes
Research Article | Physical Review Applied 15, 034080  (2021)
Max Werninghaus and Daniel J Egger and Federico Roy and Shai Machnes and Frank K Wilhelm and Stefan Filipp
Research Article | npj Quantum Information 7, 14  (2021)
M. Pechal and G. Salis and M. Ganzhorn and D. J. Egger and M. Werninghaus and S. Filipp
Research Article | arXiv:2011.08987  (2020)
M. Ganzhorn, G. Salis, D. J. Egger, A. Fuhrer, M. Mergenthaler, C. Müller, P. Müller, S. Paredes, M. Pechal, M. Werninghaus, and S. Filipp
Research Article | Physical Review Research 2, 033447  (2020)
Contact
Grant No.
H2020.765267
Funded by
European Union (EU)
Funding program
Marie Skłodowska-Curie Actions (MCSA), Innovative Training Networks (ITN)
Molecular Quantum Simulations (MOQS)
Funded by European Union (EU)
The scientific goals of MOQS are to perform experimental and theoretical quantum simulations of comparatively complex molecular structures as well as electron and energy transfer in molecular complexes. To deliver this, we first make the key transition from traditional theoretical quantum chemistry software (such as q. Monte-Carlo, Hartree-Fock, etc.) to intrinsically quantum software that can be incorporated into our superconducting circuit and Rydberg architectures.

We will tackle two sets of problems: (1) molecular structure computations of small molecular compounds and (2) excitation transfer dynamics in molecular complexes. Within this project  we will design and implement optimal algorithms that exploit quantum resources to solve chemistry problems.

Contact
Grant No.
ITN.955479
Funded by
European Union (EU)
Funding program
Marie Skłodowska-Curie Actions (MCSA), Innovative Training Networks (ITN)
Magnetomechanical Platforms for Quantum Experiments and Quantum Enabled Sensing Technologies (MagQSens)
Funded by European Union (EU)
This project seeks to establish a radically new technology platform for experiments in macroscopic quantum physics and for quantum enabled sensing. We exploit magnetic coupling between superconducting quantum circuits and superconducting mechanical resonators – both levitated and suspended – to enter a hitherto inaccessible parameter regime of both unprecedented force sensitivity and full quantum control of massive, macroscopic objects.

Our approach combines, in a new way, techniques from different research areas (magnetic levitation, superconducting circuits, atom-chip technology, cavity optomechanics and quantum optics) and is set up as a joint collaborative effort between expert European teams from academia and industry. Our technology will enable quantum experiments of otherwise unachievable coherence times and masses, which has immediate implications for testing fundamental physical questions, for performing hybrid quantum information processing and, on the applied side, for ultrasensitive force sensing applications.

Publications
Thomas Luschmann, Philip Schmidt, Frank Deppe, Achim Marx, Alvaro Sanchez, Rudolf Gross, Hans Huebl
Research Article | arXiv:2104.10577  (2021)
Schwienbacher, Daniel
PHD Thesis | Technische Universität München  (2021)
Daniel Schwienbacher, Thomas Luschmann, Rudolf Gross, Hans Huebl
Research Article | arXiv:2011.08080  (2020)
Philip Schmidt, Mohammad T. Amawi, Stefan Pogorzalek, Frank Deppe, Achim Marx, Rudolf Gross, Hans Huebl
Research Article | Communications Physics 3, 233  (2020)
Weichselbaumer, Stefan
PHD Thesis | Technische Universität München  (2020)
Daniel Schwienbacher, Matthias Pernpeintner, Lukas Liensberger, Eric R. J. Edwards, Hans T. Nembach, Justin M. Shaw, Mathias Weiler, Rudolf Gross, Hans Huebl
Research Article | Journal of Applied Physics 126, 103902  (2019)
Matthias Pernpeintner, Philip Schmidt, Daniel Schwienbacher, Rudolf Gross, Hans Huebl
Research Article | Physical Review Applied 10, 034007115002  (2018)
Philip Schmidt, Daniel Schwienbacher, Matthias Pernpeintner, Friedrich Wulschner, Frank Deppe, Achim Marx, Rudolf Gross, Hans Huebl
Research Article | Appl. Phys. Lett. 113, 152601  (2018)
Matthias Pernpeintner, Rasmus B. Holländer, Maximilian J. Seitner, Eva M. Weig, Rudolf Gross, Sebastian T. B. Goennenwein, Hans Huebl
Research Article | Journal of Applied Physics 119, 093901  (2016)
Coordinator

Markus Aspelmeyer (U Vienna)

Grant No.
H2020.736943
Funded by
European Union (EU)
Funding program
Horizon 2020, Future and Emerging Technologies (FET) Open
International Max Planck Research School "Quantum Science and Technology" (IMPRS-QST)
Funded by Max Planck Society
Quantum science and technology is a vibrant and multidisciplinary field of research at the interface of physics, mathematics, computer science and material science. With over twenty experimental and theoretical research groups, Munich is one of the leading research centres in this field. Our international graduate program unites the competences of these research groups in Munich to a common research and teaching plattform, thus offering doctoral students exiting opportunities and exceptionally broad, yet focused training at the highest level.

The International Max Planck Research School for Quantum Science and Technology is a joint program of the Max Planck Institute of Quantum Optics, the Ludwig-Maximilians-Universität München and the Technical University of Munich. It offers an excellent and coherent graduate program across the fields of atomic physics, quantum optics, solid state physics, material science, quantum information theory, and quantum many-body systems.

First and foremost, IMPRS-QST provides a platform of joint activities for a large research community, encouraging better networking and scientific exchange as an integral part of doctoral training.

IMPRS-QST students can either get directly admitted to the program through our yearly application process or join as members after starting their PhD at one of our associated research groups. 

Contact
Coordinator

Ignacio Cirac (MPQ, TUM)

Funded by
Max Planck Society
Funding program
International Max Planck Research School (IMPRS)
Munich Quantum Center (MQC)
Funded by German Research Foundation (DFG)
The Munich Quantum Center (MQC) is a virtual center promoting quantum science and technology in the greater Munich area. Within the MQC, mathematicians, theoretical and experimental physicists as well as engineers and materials scientists analyze physical systems exhibiting intriguing quantum mechanical properties and design new methods and materials for leveraging and controlling such systems, thus paving the way for the development of quantum technologies.

In the greater Munich area there is an extremely active cluster of institutions and research centers committed to the highest standards of excellence in research and teaching in the field of quantum science and technology.

The members and principal investigators of the Munich Quantum Center (MQC) research groups meet up regularly at common workshops and seminars to create a very interactive ambience for quantum science in Munich. The MQC was born at the heart of this vivid atmosphere, gathering over 50 research groups belonging to four different institutions: the Ludwig-Maximilians-Universität München, the Technical University of Munich, the Max Planck Institute of Quantum Optics, and the Walther-Meißner-Institute for Low Temperature Research.

Our research covers a wide array of topics ranging from mathematical foundations, quantum information, computational methods, quantum nano-systems, quantum optics, and quantum many-body physics to superconducting quantum devices.

Publications
Qi-Ming Chen, Florian Fesquet, Kedar E. Honasoge, Fabian Kronowetter, Yuki Nojiri, Michael Renger, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | arXiv:2107.01842  (2021)
Thomas Luschmann, Philip Schmidt, Frank Deppe, Achim Marx, Alvaro Sanchez, Rudolf Gross, Hans Huebl
Research Article | arXiv:2104.10577  (2021)
G. Terrasanta, M. Müller, T. Sommer, S. Geprägs, R. Gross, M. Althammer, M. Poot
Research Article | Materials for Quantum Technology 1, 021002  (2021)
K. G. Fedorov, M. Renger, S. Pogorzalek, R. Di Candia, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe
Research Article | arXiv:2103.04155  (2021)
Schwienbacher, Daniel
PHD Thesis | Technische Universität München  (2021)
Rudolf Gross
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 14-19  (2021)
Frank Deppe, Kirill G. Fedorov, Achim Marx
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 36-38  (2021)
Hans Hübl
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 32-35  (2021)
Stefan Filipp
Other | Akadmie Aktuell (ISSN 1436 -753X), Heft 2 (74), 20-23  (2021)
Pogorzalek, Stefan
PHD Thesis | Technische Universität München  (2020)
S. Pogorzalek, K. G. Fedorov, M. Xu, A. Parra-Rodriguez, M. Sanz, M. Fischer, E. Xie, K. Inomata, Y. Nakamura, E. Solano, A. Marx, F. Deppe, R. Gross
Research Article | Nature Communications 10, 2604  (2019)
Mikel Sanz, Kirill G. Fedorov, Frank Deppe, Enrique Solano
Research Article | 2018 IEEE Conference on Antenna Measurements Applications (CAMA), Västerås , pp. 1-4  (2018)
Edwar Xie, Frank Deppe, Michael Renger, Daniel Repp, Peter Eder, Michael Fischer, Jan Goetz, Stefan Pogorzalek, Kirill G. Fedorov, Achim Marx, and Rudolf Gross
Research Article | Applied Physics Letters 112, 202601  (2018)
Kirill G. Fedorov, S. Pogorzalek, U. Las Heras, M. Sanz, P. Yard, P. Eder, M. Fischer, J. Goetz, E. Xie, K. Inomata, Y. Nakamura, R. Di Candia, E. Solano, A. Marx, F. Deppe, R. Gross
Research Article | Scientific Reports 8, 6416  (2018)
Matthias Pernpeintner, Philip Schmidt, Daniel Schwienbacher, Rudolf Gross, Hans Huebl
Research Article | Physical Review Applied 10, 034007115002  (2018)
Jan Goetz, Frank Deppe, Kirill G. Fedorov, Peter Eder, Michael Fischer, Stefan Pogorzalek, Edwar Xie, Achim Marx, Rudolf Gross
Research Article | Physical Review Letters 121, 060503  (2018)
P. Eder, T. Ramos, J. Goetz, M. Fischer, S. Pogorzalek, J. Puertas Martínez, E.P. Menzel, F. Loacker, E. Xie, J.J. Garcia-Ripoll, K.G. Fedorov, A. Marx, F. Deppe, R. Gross
Research Article | Supercond. Sci. Technol. 31, 115002  (2018)
Philip Schmidt, Daniel Schwienbacher, Matthias Pernpeintner, Friedrich Wulschner, Frank Deppe, Achim Marx, Rudolf Gross, Hans Huebl
Research Article | Appl. Phys. Lett. 113, 152601  (2018)
Stefan Pogorzalek, Kirill G. Fedorov, Ling Zhong, Jan Goetz, Friedrich Wulschner, Michael Fischer, Peter Eder, Edwar Xie, Kunihiro Inomata, Tsuyoshi Yamamoto, Yasunobu Nakamura, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | Physical Review Applied 8, 024012  (2017)
J. Goetz, S. Pogorzalek, F. Deppe, K. G. Fedorov, P. Eder, M. Fischer, F. Wulschner, E. Xie, A. Marx, R. Gross
Research Article | Physical Review Letters 118, 103602  (2017)
U. Las Heras, R. Di Candia, K. G. Fedorov, F. Deppe, M. Sanz, E. Solano
Research Article | Scientific Reports 7, 9333  (2017)
J. Salmilehto, F. Deppe, M. Di Ventra, M. Sanz, E. Solano
Research Article | Scientific Reports 7, 42044  (2017)
J. Goetz, F. Deppe, P. Eder, M. Fischer, M. Müting, J. P. Martínez, S. Pogorzalek, F. Wulschner, E. Xie, K. G. Fedorov, A. Marx, R. Gross
Research Article | Quantum Sci. Technol. 2, 025002  (2017)
Matthias Pernpeintner, Rasmus B. Holländer, Maximilian J. Seitner, Eva M. Weig, Rudolf Gross, Sebastian T. B. Goennenwein, Hans Huebl
Research Article | Journal of Applied Physics 119, 093901  (2016)
Kirill G. Fedorov, L. Zhong, S. Pogorzalek, P. Eder, M. Fischer, J. Goetz, E. Xie, F. Wulschner, K. Inomata, T. Yamamoto, Y. Nakamura, R. Di Candia, U. Las Heras, M. Sanz, E. Solano, E. P. Menzel, F. Deppe, A. Marx, R. Gross
Research Article | Physical Review Letters 117, 020502  (2016)
J. Goetz, F. Deppe, M. Haeberlein, F. Wulschner, C. W. Zollitsch, S. Meier, M. Fischer, P. Eder, E. Xie, K. G. Fedorov, E. P. Menzel, A. Marx, and R. Gross
Research Article | Journal of Applied Physics 119, 015304  (2016)
F. Wulschner, J. Goetz, F. R. Koessel, E. Hoffmann, A. Baust, P. Eder, M. Fischer, M. Haeberlein, M. J. Schwarz, M. Pernpeintner, E. Xie, L. Zhong, C. W. Zollitsch, B. Peropadre, J.-J. Garcia Ripoll, E. Solano, K. Fedorov, E. P. Menzel, F. Deppe, A. Marx, R. Gross
Research Article | EPJ Quantum Technology 3, 10  (2016)
A. Baust, E. Hoffmann, M. Haeberlein, M. J. Schwarz, P. Eder, J. Goetz, F. Wulschner, E. Xie, L. Zhong, F. Quijandria, D. Zueco, J.-J. Garcia Ripoll, L. Garcia-Alvarez, G. Romero, E. Solano, K. G. Fedorov, E. P. Menzel, F. Deppe, A. Marx, R. Gross
Research Article | Physical Review B 93, 214501  (2016)
Max Haeberlein, Frank Deppe, Andreas Kurcz, Jan Goetz, Alexander Baust, Peter Eder, Kirill Fedorov, Michael Fischer, Edwin P. Menzel, Manuel J. Schwarz, Friedrich Wulschner, Edwar Xie, Ling Zhong, Enrique Solano, Achim Marx, Juan-José García-Ripoll, Rudolf Gross
Research Article | arXiv:1506.09114  (2015)
R. Di Candia, K. G. Fedorov, L. Zhong, S. Felicetti, E. P. Menzel, M. Sanz, F. Deppe, A. Marx, R. Gross, E. Solano
Research Article | EPJ Quantum Technology 2, 25  (2015)
Contact
Coordinator

Tatjana Wilk, LMU München

Funded by
German Research Foundation (DFG)
Funding program
Excellence Strategy
Exploring Quantum Matter (ExQM)
Funded by Bavarian State
ExQM is an international and interdisciplinary PhD programme of excellence based in Munich and jointly held by various quantum physics and mathematical research groups at Technical University of Munich (TUM), Ludwig-Maximilians-Universität Munich (LMU), the Max-Planck-Institute for Quantum Optics (MPQ), the Walther-Meißner Institute of Low-Temperature Research (WMI) and the Walter-Schottky Institute for Quantum Electronics (WSI).

The international doctoral school Exploring Quantum Matter (ExQM) focusses on a topic of growing impact on future technologies as is also reflected by the emerging EU Flagship on Quantum Science. In view of quantum-enabled technologies, the near future promises significant progress in insight into superconductivity, quantum phase transitions, quantum time-evolutions, design of quantum materials, quantum interfaces and integrated circuits thus attracting best students. A key step in this direction is simulating many-body quantum systems (with large-scale correlations) in the lab. A teaching goal is to unite the unique competences of quantum physics in Munich and extend them into an international excellence network of doctoral training centres with partners at the Austrian Academy of Science in Vienna and Innsbruck, at ETH Zurich, ICFO Barcelona, Imperial College London, Caltech, Harvard and others. In a novel format, students receive training specifically tailored to the needs of next generation scientists. New media are systematically used in the curriculum for building up an international e-library of tutorials and seminars (video recordings, some of which shall ultimately be made available as apps or itunesU).

The programme of ExQM is organised in different Research Focus Areas centred on quantum optics, numerical tensor network methods and the study of open quantum systems. ExQM is in close collaboration with the Munich Quantum Centre as well as the IMPRS doctoral school QST all within the DFG-funded excellence cluster Munich Centre for Quantum Science and Technology (MCQST).

Publications
Qi-Ming Chen, Florian Fesquet, Kedar E. Honasoge, Fabian Kronowetter, Yuki Nojiri, Michael Renger, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | arXiv:2107.01842  (2021)
K. G. Fedorov, M. Renger, S. Pogorzalek, R. Di Candia, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe
Research Article | arXiv:2103.04155  (2021)
Michael Fischer, Qi-Ming Chen, Christian Besson, Peter Eder, Jan Goetz, Stefan Pogorzalek, Michael Renger, Edwar Xie, Michael J. Hartmann, Kirill G. Fedorov, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | Physical Review B 103, 094515  (2021)
M. Renger, S. Pogorzalek, Q. Chen, Y. Nojiri, K. Inomata, Y. Nakamura, M. Partanen, A. Marx, R. Gross, F. Deppe, K. G. Fedorov
Research Article | arXiv:2011.00914  (2020)
Qi-Ming Chen, Frank Deppe, Re-Bing Wu, Luyan Sun, Yu-xi Liu, Yuki Nojiri, Stefan Pogorzalek, Michael Renger, Matti Partanen, Kirill G. Fedorov, Achim Marx, Rudolf Gross
Research Article | arXiv:1912.09861  (2019)
S. Pogorzalek, K. G. Fedorov, M. Xu, A. Parra-Rodriguez, M. Sanz, M. Fischer, E. Xie, K. Inomata, Y. Nakamura, E. Solano, A. Marx, F. Deppe, R. Gross
Research Article | Nature Communications 10, 2604  (2019)
Edwar Xie, Frank Deppe, Michael Renger, Daniel Repp, Peter Eder, Michael Fischer, Jan Goetz, Stefan Pogorzalek, Kirill G. Fedorov, Achim Marx, and Rudolf Gross
Research Article | Applied Physics Letters 112, 202601  (2018)
Kirill G. Fedorov, S. Pogorzalek, U. Las Heras, M. Sanz, P. Yard, P. Eder, M. Fischer, J. Goetz, E. Xie, K. Inomata, Y. Nakamura, R. Di Candia, E. Solano, A. Marx, F. Deppe, R. Gross
Research Article | Scientific Reports 8, 6416  (2018)
Jan Goetz, Frank Deppe, Kirill G. Fedorov, Peter Eder, Michael Fischer, Stefan Pogorzalek, Edwar Xie, Achim Marx, Rudolf Gross
Research Article | Physical Review Letters 121, 060503  (2018)
P. Eder, T. Ramos, J. Goetz, M. Fischer, S. Pogorzalek, J. Puertas Martínez, E.P. Menzel, F. Loacker, E. Xie, J.J. Garcia-Ripoll, K.G. Fedorov, A. Marx, F. Deppe, R. Gross
Research Article | Supercond. Sci. Technol. 31, 115002  (2018)
Stefan Pogorzalek, Kirill G. Fedorov, Ling Zhong, Jan Goetz, Friedrich Wulschner, Michael Fischer, Peter Eder, Edwar Xie, Kunihiro Inomata, Tsuyoshi Yamamoto, Yasunobu Nakamura, Achim Marx, Frank Deppe, Rudolf Gross
Research Article | Physical Review Applied 8, 024012  (2017)
J. Goetz, S. Pogorzalek, F. Deppe, K. G. Fedorov, P. Eder, M. Fischer, F. Wulschner, E. Xie, A. Marx, R. Gross
Research Article | Physical Review Letters 118, 103602  (2017)
J. Goetz, F. Deppe, P. Eder, M. Fischer, M. Müting, J. P. Martínez, S. Pogorzalek, F. Wulschner, E. Xie, K. G. Fedorov, A. Marx, R. Gross
Research Article | Quantum Sci. Technol. 2, 025002  (2017)
Kirill G. Fedorov, L. Zhong, S. Pogorzalek, P. Eder, M. Fischer, J. Goetz, E. Xie, F. Wulschner, K. Inomata, T. Yamamoto, Y. Nakamura, R. Di Candia, U. Las Heras, M. Sanz, E. Solano, E. P. Menzel, F. Deppe, A. Marx, R. Gross
Research Article | Physical Review Letters 117, 020502  (2016)
J. Goetz, F. Deppe, M. Haeberlein, F. Wulschner, C. W. Zollitsch, S. Meier, M. Fischer, P. Eder, E. Xie, K. G. Fedorov, E. P. Menzel, A. Marx, and R. Gross
Research Article | Journal of Applied Physics 119, 015304  (2016)
F. Wulschner, J. Goetz, F. R. Koessel, E. Hoffmann, A. Baust, P. Eder, M. Fischer, M. Haeberlein, M. J. Schwarz, M. Pernpeintner, E. Xie, L. Zhong, C. W. Zollitsch, B. Peropadre, J.-J. Garcia Ripoll, E. Solano, K. Fedorov, E. P. Menzel, F. Deppe, A. Marx, R. Gross
Research Article | EPJ Quantum Technology 3, 10  (2016)
A. Baust, E. Hoffmann, M. Haeberlein, M. J. Schwarz, P. Eder, J. Goetz, F. Wulschner, E. Xie, L. Zhong, F. Quijandria, D. Zueco, J.-J. Garcia Ripoll, L. Garcia-Alvarez, G. Romero, E. Solano, K. G. Fedorov, E. P. Menzel, F. Deppe, A. Marx, R. Gross
Research Article | Physical Review B 93, 214501  (2016)
Max Haeberlein, Frank Deppe, Andreas Kurcz, Jan Goetz, Alexander Baust, Peter Eder, Kirill Fedorov, Michael Fischer, Edwin P. Menzel, Manuel J. Schwarz, Friedrich Wulschner, Edwar Xie, Ling Zhong, Enrique Solano, Achim Marx, Juan-José García-Ripoll, Rudolf Gross
Research Article | arXiv:1506.09114  (2015)
R. Di Candia, K. G. Fedorov, L. Zhong, S. Felicetti, E. P. Menzel, M. Sanz, F. Deppe, A. Marx, R. Gross, E. Solano
Research Article | EPJ Quantum Technology 2, 25  (2015)
Contact
Coordinator

Thomas Schulte-Herbrüggen (TUM)

Funded by
Bavarian State
Funding program
Elite Network of Bavaria
From Electronic Correlations to Functionality (TRR80)
Funded by German Research Foundation (DFG)
The collaborative research center TRR 80 connects fundamental research on emergent new materials properties driven by strong electronic correlations with the focussed exploration for possible new functionalities in technological devices. At the heart of the materials properties of interest are the strong interplay of charge, spin, orbital, and lattice degrees of freedom, leading to a multitude of complex new phases on different length and time-scales with fascinating electronic properties as well as novel generic excitations. Systematic determination of large susceptibilities to applied fields, perturbations and defects yield complex phase diagrams, which represent a major avenue towards tailored functionalities that may be exploited in designed composite-systems. Research in TRR 80 focusses in particular on novel phenomena in d- and f-electron materials.

Since the start of the Transregio in 2010 the successful development of experimental and theoretical tools to tackle correlated electron systems provided a basis for shaping and advancing this mission in the second and upcoming third funding period. These activities are organized in terms of three research areas comprising the synthesis and characterization of correlated quantum matter with non-trivial topological properties (research area E), the investigation of their emergent excitations utilizing a variety of dynamical methods (research area F) and utilization of reduced dimensions and interfaces for functionalization (research area G). Within the third funding period of the Transregio, the most interesting and promising avenues to realize and implement novel functionalities will be addressed by combined experimental and theoretical efforts across the different research areas E, F, and G. These arise, in particular, from the interplay of electronic correlations and non-trivial topological winding in real and reciprocal space, driven by large spin-orbit coupling, and from electronic reconstructions in thin films, heterostructures, surfaces and interfaces.

The research program presented in the following exploits the very broad spectrum of experimental and theoretical techniques available at the participating institutions. In addition to the University of Augsburg and the Technische Universität München, with its high-intensity neutron source Heinz Maier-Leibnitz, research groups from the University of Duisburg-Essen, the Walther Meissner Institute for Low Temperature Research of the Bavarian Academy of Sciences (München), the Max Planck Institute for Solid State Research (Stuttgart), and the École Polytechnique Fédérale de Lausanne will jointly tackle a broad range of challenges in the description and manipulation of correlated electron materials.

As a unique feature, the consortium includes an unusually broad range of advanced methods to achieve its goals. High-quality single crystalline bulk as well as thin film and heterostructure samples across different material classes will be synthesized and characterized. The materials prepared will be investigated by a large variety of diffractive and spectroscopic methods, and the results modeled in terms of material-specific density-functional theory as combined with powerful techniques based on dynamical mean-field theory. The expertise of the principal investigators involved includes the theoretical treatment of many-body localization and spectroscopic studies of the impact of disorder on correlated electronic structures - representing one of the most outstanding problems of 21st century physics. Taken together, the symbiosis of all the available methods and techniques for gaining a deep understanding of the fundamental properties of bulk materials and highly sophisticated, tailored heterostructures will allow harvesting novel functionalities that originate in strong electronic correlations.

Publications
Lukas Liensberger, Franz X. Haslbeck, Andreas Bauer, Helmuth Berger, Rudolf Gross, Hans Huebl, Christian Pfleiderer, Mathias Weiler
Research Article | arXiv:2102.11713  (2021)
Tianyi Liu, Daniel Jost, Brian Moritz, Edwin W. Huang, Rudi Hackl, Thomas P. Devereaux
Research Article | arXiv:2101.07486  (2021)
N. Lazarević and R. Hackl
Review | Journal of Physics: Condensed Matter 32, 413001  (2020)
S. Lederer, D. Jost, R. Hackl, E. Berg, S.A. Kivelson
Research Article | Philosophical Magazine, Part B: Condensed Matter Physics 100, 2477  (2020)
Harrison Ruiz, Yao Wang, Brian Moritz, Andreas Baum, Rudi Hackl, and Thomas P. Devereaux
Research Article | Physical Review B 99, 125130  (2019)
A. Baum, H. N. Ruiz, N. Lazarevic, Yao Wang, T. Böhm, R. Hosseinian Ahangharnejhad, P. Adelmann, T. Wolf, Z. V. Popovic, B. Moritz, T. P. Devereaux, and R. Hackl
Research Article | Communications Physics 2, 14  (2019)
Contact
Coordinator

Philipp Gegenwart (U Augsburg)

Grant No.
TRR80
Funded by
German Research Foundation (DFG)
Funding program
Collaborative Research Centre (SFB/TRR)
Multi-qubit Gates for the Efficient Exploration of Hilbert Space with Superconducting Qubit Systems
Funded by German Research Foundation (DFG)
The goal of this research project is to explore the potential of multi-qubit gates for quantum computing. The main focus is on speeding up quantum algorithms based on the variational quantum eigensolver (VQE) method on a superconducting qubit platform.

This quantum algorithm determines the groundstate of a given Hamiltonian, for example a molecular electronic configuration Hamiltonian. The quantum state of the system is steered to the target state by varying parameters of a gate sequence on the qubits to optimize a cost function on a classical computer. The advantage of such a hybrid quantum-classical computation over a purely classical one is that high-dimensional multi-qubit states can be stored efficiently on the quantum device, which is not possible on a classical memory because of the exponentially large number of state coefficients. The challenge on today’s quantum computers is, however, that the VQE algorithm has to converge to the target state before decoherence sets in. It's circuit-depth must be short. The main aim of this project is, therefore, to explore the efficient generation of multi-qubit states going beyond the current paradigm of decomposing all state manipulations into single and two-qubit gates. We will investigate multi-qubit operations that will allow us to entangle multiple qubits at the same time. This will result in short-depth efficient algorithms provided that the fidelity of the multi-qubit gate can be kept high. We use fixed-frequency transmon qubits and two-qubit gates based on parametrically driven tunable couplers. We address the question if there is an advantage in using multi-qubit gates over traditional two-qubit gates not only in theory but also in practical experiments. While theoretically the answer is likely to be affirmative, on the experimental side it is not clear what gate fidelities can be reached and how these compare to a decomposition of multi-qubit gates into two-qubit interactions. We explore N-way tunable couplers that are either capacitively and galvanically coupled to N qubits and evaluate the maximum number of qubits. We investigate multi-qubit entangling interactions via parametric frequency-modulation of the coupler. Different methods are compared, such as resonant or dispersive interactions based on simultaneous pulses to generate different classes of entangled states. The final goal is a four-qubit experiment targeting a quantum chemistry problem, such as determining the ground state and energy spectrum of molecular hydrogen (H2), and to assess the efficiency of multi-qubit gates. It is straightforward to then extend the methods that are tested in this project with a few qubits to larger systems to bring practical applications closer within reach by adding building blocks with higher connectivity and multi-qubit gate capabilities.

Contact
Grant No.
FI 2549/1-1
Funded by
German Research Foundation (DFG)
Funding program
Individual Research Grant
Evolution of the charge carrier properties and electronic correlations in layered organic metals near the Mott metal-insulator transition
Funded by German Research Foundation (DFG)
The Mott transition is one of the most fundamental correlation-driven instabilities in normal metals. Despite extensive studies, there are important unresolved problems and open questions, in particular regarding the experimental study of the metallic ground state in the immediate vicinity of the insulating state in well-defined model systems.

Within this project, we join experts from experimental and theoretical physics and materials science to tackle these problems. We will employ kappa-type organic charge transfer salts as quasi-2D electronic model systems with bandwidth-controlled Mott instability for tracking the evolution of key characteristics of the charge carriers in the metal/insulator coexistence region of the phase diagram as well as in the neighboring homogeneous metallic state. In particular, we will study (i) the correlation-induced renormalization of the effective mass, (ii) the exact geometry and topology of the Fermi surface, and (iii) the coherence of charge transport. The systematic study of these characteristics in well-defined model systems will provide a crucial test for the existing theories of the Mott metal-insulator transition.A key objective of the project is the disentanglement of contributions of charge, spin, and lattice degrees of freedom to the metal-insulator instability. This problem will be addressed by studying kappa-type salts with different strength of geometrical frustration, magnetic interactions, and lattice disorder. The salts of BEDT-TTF with different anions are particularly suited for studying the effects of geometrical frustration, while BETS salts with localized magnetic moments give access to the interplay between electronic correlations and magnetic interactions. The coupling of the electronic state to lattice degrees of freedom will be probed by studying the influence of deuteration of BEDT-TTF salts on the charge carrier properties and by tracing the impact of ethylene-group disorder in these salts.The main experimental probes for addressing the above issues will be magnetic quantum oscillations, semiclassical anisotropic magnetotransport, and resistivity anisotropy. A precise control of the electronic ground state with respect to the metal-insulator boundary will be realized by fine-tuning materials with quasi-hydrostatic pressure as well as "chemical pressure". A quantitative analysis of the experimental results will be carried out by the theory team involved in the project using the state-of-the-art theory of high-field magnetotransport in quasi-2D metals as well as of the charge transport in phase-separated electronic media. Further development of the (magneto)transport theory in the segments related to the proposed experiments is planned.The availability of top-quality single crystals of kappa-type salts is crucial for the success of the planned project. The preparation and characterization of such crystals will be carried out by the experienced materials science team of the project.

Publications
R. Ramazashvili, P. D. Grigoriev, T. Helm, F. Kollmannsberger, M. Kunz, W. Biberacher, E. Kampert, H. Fujiwara, A. Erb, J. Wosnitza, R. Gross & M. V. Kartsovnik
Research Article | npj Quantum Materials 6, 11  (2021)
V.N. Zverev, W. Biberacher, S. Oberbauer, I. Sheikin, P. Alemany, E. Canadell, M.V. Kartsovnik
Research Article | Physical Review B 99, 125136  (2019)
Team
Grant No.
KA 1652/5-1, GR 1132/19-1
Funded by
German Research Foundation (DFG)
Funding program
Individual Research Grant
Towards pure spin currents in epitaxial all oxide heterostructures
Funded by German Research Foundation (DFG)
Over the last years, the generation and detection of pure spin currents, i.e. the flow of angular momentum without any accompanying charge current, has been successfully realized. This opened fascinating opportunities for fundamental physics experiments and novel applications in spin electronics. However, a profound understanding of the phenomena associated with pure spin currents and the materials systems suitable for their study is still missing.

The main objective of this research proposal is the systematic study of pure spin current physics in all oxide heterostructures, which are promising for this purpose but hardly investigated so far. On the one hand, the planned experiments are expected to provide a profound understanding of the rich variety of phenomena associated with spin-orbit interaction in oxide materials and its dependence on the specific material parameters. On the other hand, the project aims to develop and investigate novel materials with large spin Hall angle, i.e. with a large efficiency for electrical generation and detection of pure spin currents. Moreover, it aims at the tunability of spin-orbit coupling in oxides via strain, oxygen vacancies, and temperature. The boost of the efficiency for spin current generation and detection is a prerequisite for the application of pure spin currents in efficient spintronic devices. The ambitious project objectives will be met by fabricating high-quality oxide heterostructures by laser-molecular beam epitaxy and by systematically studying pure spin current generation and detection in experiments based on longitudinal spin Seebeck effect and spin Hall magnetoresistance. The applicants contribute broad expertise in both thin film technology and the experimental characterization techniques for spin current phenomena to the successful implementation of the ambitious research program.

Publications
Paul Rosenberger, Matthias Opel, Stephan Geprägs, Hans Huebl, Rudolf Gross, Martina Müller, Matthias Althammer
Research Article | Applied Physics Letters 118, 192401  (2021)
J. Gückelhorn, T. Wimmer, S. Geprägs, H. Huebl, R. Gross, and M. Althammer
Research Article | Applied Physics Letters 117, 182401  (2020)
Grant No.
AL 2110/2-1
Funded by
German Research Foundation (DFG)
Funding program
Individual Research Grant
Spin dynamics of hybrid skyrmion-magnon solitons
Funded by German Research Foundation (DFG)
The transport and manipulation of magnetic texture offers a promising pathway for future information storage and transfer with enhanced functionality. Nanoscale, topologically protected magnetic whirls called skyrmions are particularly intriguing for this purpose.
The realization of skyrmionic devices relies on understanding and manipulating skyrmion dynamics. Broadband magnetic resonance is an established tool for spectroscopy of magnetically ordered thin films. This technique has already shown its potential for the investigation of skyrmion and helimagnon dynamics in isolated chiral magnets. Ferromagnetic multilayers form the basis of today’s spintronic devices and multilayers of chiral magnets and ferromagnets may be similarly important in future skyrmionic devices. However, such hybrid multilayers have rarely been experimentally studied so far. In this project, we will exploit static and dynamic coupling of spin texture and dynamics in these chiral magnetic thin film heterostructures to generate novel topological ground states, interactions and excitations. In particular, static coupling can be mediated by exchange interactions, while dynamic coupling will also arise due to spin current flow across the chiral magnet/ferromagnet interface. We will use broadband magnetic resonance spectroscopy to quantify spin dynamics at the crossing of ferromagnet and chiral magnet dispersions. In this way, we will investigate the potential of exciting dynamics of novel hybrid skyrmion-magnon modes. Furthermore, at the ferromagnet/chiral magnet interface, exotic topological structures such as skyrmion cones are predicted to emerge. These topological solitons are fundamentally interesting and might have great application potential and intriguing dynamic properties, which we will explore. A novel two-tone microwave spectroscopy method will be employed for the study of nonlinear interactions between skyrmion and magnon excitations in these multilayers. These nonlinear interactions might be useful to control, e.g. magnetic damping of skyrmion excitations.Finally, we will use travelling spin wave spectroscopy to study magnon propagation in the presence of an adjacent skyrmion lattice, which can serve as a natural nanoscale magnonic grating coupler and magnonic crystal. These experiments unite the disciplines of magnonics and skyrmionics.
Publications
Luis Flacke, Valentin Ahrens, Simon Mendisch, Lukas Körber, Tobias Böttcher, Elisabeth Meidinger, Misbah Yaqoob, Manuel Müller, Lukas Liensberger, Attila Kákay, Markus Becherer, Philipp Pirro, Matthias Althammer, Stephan Geprägs, Hans Huebl, Rudolf Gross, Mathias Weiler
Research Article | arXiv:2102.11117  (2021)
Tobias Hula, Katrin Schultheiss, Aleksandr Buzdakov, Lukas Körber, Mauricio Bejarano, Luis Flacke, Lukas Liensberger, Mathias Weiler, Justin M. Shaw, Hans T. Nembach, Jürgen Fassbender, and Helmut Schultheiss
Research Article | Applied Physics Letters 117, 042404  (2020)
Luis Flacke, Lukas Liensberger, Matthias Althammer, Hans Huebl, Stephan Geprägs, Katrin Schultheiss, Aleksandr Buzdakov, Tobias Hula, Helmut Schultheiss, Eric R. J. Edwards, Hans T. Nembach, Justin M. Shaw, Rudolf Gross, Mathias Weiler
Research Article | Applied Physics Letters 115, 122402  (2019)
Lukas Liensberger, Luis Flacke, David Rogerson, Matthias Althammer, Rudolf Gross, Mathias Weiler
Research Article | IEEE Magnetics Letters 10, 5503905  (2019)
Coordinator

Christian Pfleiderer (TUM)

Grant No.
SPP 2137
Funded by
German Research Foundation (DFG)
Funding program
Priority Programme (SPP)