BeyondC: Quantum Information Systems Beyond Classical Capabilities
A special research program (SFB) of the Austrian Science Fund (FWF): BeyondC
After two decades of intensive experimental and theoretical research in quantum science, we have now reached a new era of quantum technologies. Several scenarios have been identified for which quantum information processing outperforms its classical analogue. We explore these new possibilities in a consortium with the expertise of seven experimental physics groups led by G. Kirchmair, T. Monz, G. Weihs (University of Innsbruck), Ch. Roos (IQOQI Innsbruck), J. Fink (IST Austria), Ph. Walther (University of Vienna) and six theory groups led by J. I. Cirac (MPQ, Garching, Germany), H. Briegel, B. Kraus, W. Lechner (University of Innsbruck), C. Brukner, F. Verstraete (University of Vienna).
P05 – Integrating Superconducting Quantum Circuits: Superconducting processors offer fast clock speeds and a promising potential for scalability, but even with state of the art gate fidelities an excessive overhead of physical qubits is required to encode each single logical qubit. Our long-term goal is to lay the scientific foundation of a highly integrated chip-based quantum computer hardware that is ready for both, fast local processing and long-distance quantum communication. The first 4 years will be dedicated to improving single and few qubit properties and to study the interaction and dynamics of medium-scale integrated quantum circuits. In the first part we will investigate new directions to reduce the circuit size without compromising coherence by employing new types of substrates, fabrication technology and circuit designs. In the second part we will investigate the potential of collective multi-qubit states for analog quantum simulation, sensing and quantum annealing. Towards the end of the reporting period we plan to use the developed qubit hardware as a non-classical resource in long-distance fiber optic quantum networks.
Team: Martin Zemlicka, Elena Redchenko
QUNNECT: A Fiber Optic Transceiver For Superconducting Qubits
Research in optical quantum networks and superconducting devices has progressed largely independently so far. While superconducting qubits are ideally suited for on-chip integration and fast processing, they are problematic for quantum communication. No solution exists to connect remote qubits via a room temperature link. The small energy scales in the electrical circuit make the fragile information carriers (single microwave photons) susceptible to interference, thermal noise and losses, which has hindered any significant progress in this direction.
We recently have gained sufficient insight into low loss materials, the required fabrication technology, and the precision measurement techniques necessary to bridge the two worlds, by controlling individual photons and phonons quantum coherently. We are working towards integrating silicon photonics for low-loss fiber optic communication with superconducting circuits for quantum processing on a single microchip. As intermediary transducer we will focus on two approaches:
(1) quantum ground state cooled nanoscale mechanical and
(2) low-loss electro-optic nonlinear circuit elements.
The novelty of our approach in QUNNECT is the tight on-chip integration facilitated by our groups interdisciplinary background in both, superconducting circuits and silicon nanophotonics. Integration will be the key for realizing a low-loss and high-bandwidth transceiver, for preparing remote entanglement of superconducting qubits, and for extending the range of current fiber optic quantum networks.
Team: William Hease, Shabir Barzanjeh, Alfredo Rueda
Hybrid Semiconductor – Superconductor Quantum Devices
Using quantum states of microscopic physical systems for more effective problem solving is not a new idea, but only just now, after many decades of basic research, nanofabrication and quantum control technology have evolved sufficiently to make an attempt to build a microchip-based quantum computer. While it is clear that drastic algorithmic improvements are still needed for useful quantum processing, there is also no consensus about the ideal hardware to use. Very important basic questions are still unanswered. Can we find designs with built-in hardware-protection to extend the coherence times of superconducting qubits further? How can we reliably generate, detect and make use of exotic quasiparticles such as Majorana fermions?
In this project funded by a NOMIS research grant we join forces with the Katsaros group to give answers to these important questions. The goal is to improve the properties of superconducting and semiconducting qubits and to couple them with superconducting bus systems. Such hybrid devices might prove to be the most promising building blocks for future quantum devices.
Team: Matilda Peruzzo, Farid Hassani
HOT: Hybrid Optomechanical Technologies
The HOT consortium funded by the European Union Future and Emerging Technology proactive scheme aims to lay the foundation for a new generation of devices, which connect or even contain, several platforms at the nanoscale in a single “hybrid” system. As hybrid interfaces they will allow the exploitation of the unique advantages of each subsystem within a nano-scale footprint, while as integrated hybrid devices they will enable entirely novel functionalities.
A particular focus is to explore hybrid opto- and electro-mechanical devices operating at the physical limits for conversion, synthesis, processing, sensing and measurement of electromagnetic (EM) fields, from radio and microwave frequencies to the terahertz domain. These spectral regions are relevant to the important existing application domains of medicine (e.g. MRI imaging), security (e.g. Radar and THz monitoring), positioning, timing and navigation (oscillators) and for future quantum technology.
Team: Matthias Wulf, Georg Arnold