STRATEGIC PACKAGE: Superconductors-Based Quantum Technologies

Lead Research Organisation: Lancaster University
Department Name: Physics

Abstract

Quantum technologies (QT) is a truly interdisciplinary research area that aims to build novel functional devices based on quantum principles and thus showing unique characteristics when compared with conventional devices based on classical physics. The future feasibility of QT critically depends on one's ability to create, protect, manipulate and measure quantum states in physical, chemical or biological systems. In order to be in the quantum regime, a system must have energy levels that are well protected from all possible sources of decoherence. In general, decoherence has two major contributions - dephasing and energy relaxation - both inflicted by the environment. Superconducting materials are a natural choice for building solid-state quantum circuits, since superconductivity offers coherence. Superconductors have an energy region, in which only one energy level exists, the Fermi level, while all other energy levels are separated by the superconducting energy gap: the Cooper pairs of conducting electrons condense to this energy level, which is automatically protected from low-energy excitations because of the presence of the gap. This allows to prepare, to control, and to manipulate quantum states in superconductors-based nanostructures for the use in various devices whose operation is based upon quantum principles.

A niche of superconductors-based QT, including the development and use of superconducting qubits, remains almost untamed by the UK researchers. According to the recent IoP Review, the UK plays a major role in several other areas of research on quantum computer technologies: studies of spin qubits (Oxford), semiconductor quantum dots (Sheffield), trapped ions (Oxford, ICL, Sussex, NPL), trapped atoms (Strathclyde, Oxford), and development of photon-based QT (Toshiba-Cambridge, Bristol, Sheffield, Oxford), however, "... the UK has not yet done much work on superconducting qubits...". These solid-state qubits were the first implemented experimentally by Nakamura, Pashkin and Tsai at NEC, and our ambition is to create, by relocation of Y. Pashkin to Lancaster, the new Centre of excellence which will broadly address the development and applications of superconductors-based QT, successfully competing against the existing renown QT groups, such as those at Yale (USA), CEA Saclay (France), TUDelft (the Netherlands), and Q-Station at UCSB (USA). The new center of excellence in experimental research in superconductors-based QT (SQT) will study fundamental properties of a wide range of superconductors-based nanostructures aiming to develop their applications in quantum metrology, nanoelectromechanics and sensing applications, and - in the long term - quantum information processing.

Planned Impact

The promise of Quantum Technologies to generate positive impact on the future of industries in the UK is the reason for this direction of research be included in the EPSRC Grand Challenges in Physics. We expect that the studies of extreme properties of superconductors-based nanostructures by the new group will result in making quantum technologies reality, by developing novel sensors and various high-end instrumentation. On the side of fundamental science, the new group will disseminate its findings through publications in specialized and general high-impact journals, such as Physical Review Letter, Science, Nature Magazine group. On the side of instrumentation development, the new results obtained by the group will be disseminated via participation in nanotechnology forums, and by advertising prototype devices at national and international technological exhibitions.

The first and most direct practical use of the SQT aimed by the new group will be the development of quantized current standard, which one of the key goals in the Euramet Strategy 2020, which will be followed by the development of ultrasensitive nano-sensors. These innovations will find their way into high-value high-tech industries through the direct collaborations and partnerships, and they will have a positive impact on the UK-based high-tech enterprises of various sizes, such as the already committed collaborators Oxford Instruments, National Physical Laboratory Plc, Graphene Industries Ltd. Pashkin's group will also work closely with the new spin-off Lancaster Cryogenics Ltd, by producing new types of temperature gauge and sensors.

The development of new instrumentation will also have positive impact on the academic community in the UK, reaching far beyond physics. By creating measurement devices with ultra-high sensitivity, the new group will enhance various branches of materials science, chemistry and biology - all in a constant need of new highly sensitive instrumentation. Based on that, a new spin-off may be created at Lancaster, to manufacture devices based on the use of quantum technology for sensing.

Enabling new type of information processes and signals analysis would have a major impact on engineering and communication, thus, creating potential for new investments in the UK from the private sector and attracting multinationals. To this end, Pashkin will actively cooperate with Nippon Electronics Corporation (NEC, Japan), thorough direct collaborative projects and knowledge transfer. Also, the group is on its way to establishing a collaboration with Samsung (Korea), on the development of superconducting proximity-effect transistor based on graphene and other two-dimensional materials.

The research projects run by the new group will help to train the new generation of highly skilled researchers and technologists. In the first instance, these will be junior researcher and PhD students involved in the advance nanofabrication and characterization processes funded by the proposed Strategic Package. We have already been told, during the recent site visit by Oxford Instruments, that such experts, trained by Pashkin's group, will be more than welcome to join their workforce. Beyond that, the new group will be actively involved in training activities of the EPSRC Centre for Doctoral Training NOWNANO (in which the CI of this application is a co-director), by offering specialist training in SQT and hosting students for research projects, and it will train PhD students on the recently signed joint doctoral program between LU and An Najah University in Nablus, who will return to their home University as faculty to build up higher education in sciences in Palestine.

Publications

10 25 50
 
Description This award, in combination with the major investments by the University in the nanofabrication and cryogenic infrastructure, has led to the establishment of substantial research capabilities in the field of superconducting quantum circuits, nanoelectronic hybrid structures and nanoelectromechanical systems. The new research group formed in 2012 and supported by this award has become fully autonomous and already demonstrated its ability to win research grants and do high-quality research. In accordance with the research plan, research was conducted along the three main directions: superconducting quantum bits, quantum metrology and nanoelectromechanical systems, and resulted in ten journal publications. The award objectives were met fully.
The most significant achievements include:
1. Demonstration of electron pumping using RF-driven hybrid SINIS-type single-electron turnstiles including their parallel operation. Experimental evidence of the interplay of the inverse proximity effect and magnetic field revealing itself in the superconducting gap enhancement and significant improvement of the turnstile characteristics. The observed interplay and its theoretical explanation in the context of QP overheating are important for various superconducting and hybrid nanoelectronic devices, which find applications in quantum computation, photon detection, and quantum metrology. These experiments are especially important in view of the redefinition of the unit of electric current, the ampere, which is taking place in May 2019.
2. Measurement of electron temperature in nanoelectronic devices below 4 mK using primary thermometry. This was the record low electron temperature at that time. Further cooling of electrons was achieved by using on-chip nuclear demagnetisation, a technique that was pioneered at Lancaster. Cooling electrons is essential in improving performance of quantum and classical electronic devices.
3. In collaboration with the ULT Group in Lancaster, we have pioneered a new technique to probe quantum fluids, that is by using nanoscale mechanical resonators immersed in superfluids. The devices are shown to be very sensitive detectors of the superfluid density and the normal fluid damping in 4He. This opens a possibility to apply them in superfluid 3He which can be routinely cooled to below 100 ┬ÁK. This brings us into the regime where nanomechanical devices operating at a few MHz frequencies may enter their mechanical quantum ground state.
4. Using the multiplexing architecture, we have demonstrated a circuit comprising eight transmon qubits coupled to coplanar waveguide resonators that could be addressed individually through a common feed line. The measured device parameters agreed with the designed values, and the resonators and qubits exhibit excellent coherence properties and strong coupling. Our analysis showed that the circuit was suitable for generation of single microwave photons on demand with an efficiency exceeding 80%.
Exploitation Route See above.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics

 
Description Y Pashkin has co-authored with Lindstrom (NPL), Russel (NIST) and Manninen (VTT) an article in a popular magazine Microwave Journal describing challenges and opportunities in the rapidly developing field of microwave photonics. We argued the suitability of superconducting quantum circuits for generation and detection of single microwave photons. These novel technologies may find applications in space communications and precision metrology in the near future. In the longer run, they will be in demand in quantum communication and quantum computing. Our results on controlled transfer of single electrons through hybrid nanoelectronic devices together with the results by other groups have led to the decision by the metrology authorities to redefine the unit of electric current, the ampere, which will be implemented in May 2019. The precise current sources developed with these techniques will allow to close the quantum metrology triangle.
First Year Of Impact 2018
Sector Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics
Impact Types Economic

 
Description Disruptive Investigations 
Organisation BAE Systems
Department BAE Systems Military Air & Information
Country United Kingdom 
Sector Private 
PI Contribution We have prepared a package of slides reviewing the status and prospects of quantum technologies for computing, sensing and communication in view of the further developments withing BAE Systems.
Collaborator Contribution Our partners from BAE Systems participated in several discussions to guide us in our review work.
Impact N/a
Start Year 2015
 
Description Innovate UK project with OI 
Organisation Oxford Instruments
Country United Kingdom 
Sector Private 
PI Contribution Characterisation of a novel type of a magnetic field sensor at mK temperature.
Collaborator Contribution Development of a concept of a user-friendly, portable, compact and inexpensive dilution refrigerator.
Impact N/a
Start Year 2015