In this proposal we request funding to investigate the synthesis, structures and electronic/magnetic properties of a variety of new transition metal oxychalcogenides. These are relatively unusual materials which simultaneously contain an oxide (O2-) and a second chalcogenide (S2-, Se2-, Te2-) anion, as opposed to more commonly found species such as sulfates or sulfites (SO42- and SO32-) in which the chalcogen has a positive formal charge. Mixed anion materials are interesting as they frequently contain transition metals in unusual chemical or electronic environments. This can lead to materials with unexpected and fascinating electronic, magnetic or optical properties. A now-classic example of this was the 2008 discovery by Hosono et al. of 26 K superconductivity (now known at temperatures up to 55 K) in materials derived from a oxypnictide LaOFeAs. Superconductivity in an iron-based system such as this at such high temperatures was unprecedented, entirely unexpected and led to significant world-wide interest. Other interesting mixed anion phases include materials such as LnOCuS (Ln = lanthanide) and La2O2CdSe2, which are rare examples of p-type transparent conductors, and could find a range of applications in display devices. In this research programme we plan work in three main areas. Firstly, we want to tune the electronic properties of a fascinating and unusual family of materials of composition Ln2O2M2OSe2 (Ln = lanthanide, M = transition metal). These are closely related to the superconducting pnictide systems but, in their undoped state, lie on the insulator side of a insulator-to-metal boundary. We plan various approaches to chemically modify them to change their conductivity, ideally towards the superconducting region of the phase diagram, and to understand both their structural and physical properties. Secondly, we aim to extend our recent successes in the preparation of novel materials with the closely related composition Ln2O2MSe2. We again aim to understand, control and exploit their electrical and optical properties. We believe discoveries here will also help understand the pnictide systems. In our final work strand we believe that we can adopt a variety of ideas learned from our work and that of others to prepare new families of materials of general formula (LnOQ)1-xMx and (LnOQ)1-xMQx - what we call "4 Angstrom phases". Our aim is to explore the properties of these new phases. The synthetic side of our work will be supported via a variety of characterisation and theoretical methods. We will apply X-ray and neutron scattering techniques to probe the structures, structural changes and magnetic interactions in the materials. The physical properties of interesting materials (conductivity, magnetism, heat capacity, etc) will be measured using equipment available in Durham. Plane wave density functional theory will be used to help us predict and understand the properties of materials targetted or prepared. We believe this synergic approach will allow rapid and insightful progress.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

In the last ten to fifteen years there has been a world-wide expansion in investigation into quantum states of light. Much of the expansion in this subject area has been stimulated by the emergence of quantum cryptography or quantum key distribution (QKD) / first proposed in 1984 - which offers unconditionally secure information sharing guaranteed by quantum-mechanical laws. Whilst QKD still remains a fertile subject of exciting laboratory and field research, experimental progress in free-space and optical fibre transmission media have taken quantum cryptography to the fringes of commercial exploitation and real-world application. Concurrently, a number of other developments in quantum information research have also been highly significant, such as quantum computing algorithms that, if realised, would make today's public-key based data security system obsolete. The building blocks, or quantum components, of these quantum-based systems require considerable research effort and this is the main subject matter of this proposal. Significantly and perhaps in a more short-term manner, a number of these components will be utilised in other applications outside the quantum information processing sphere; these applications include including low-light level communications (eg as proposed in the NASA Mars Communications Programme), in remote sensing, low light level imaging, quantum or ghost imaging, and quantum-based metrology. This Platform Grant application from the Heriot-Watt group centres on leading edge research into the creation, detection and exploitation of the quantum states of light. This project will be used to make strategic decisions regarding research in these fast-moving fields. At the time of application, several exciting projects have been highlighted for investigation, although these projects are not meant to represent a comprehensive and exclusive list of research topics. Some areas worth immediate investigation include novel solid-state indistinguishable single photon sources, photon-number resolving detectors, optical generation of spin entanglement, few photon non-linearities with 'waveguide-QED', and large alphabet QKD. Whilst this grant will not provide the full resources for long-term investigations into all these areas, this project will permit rapid start-up and allow the group to collaborate more effectively with other groups, including overseas researchers.

The vision of this project is to develop practical quantum technology for the accurate measurement of electrical currents and to develop high sensitivity detectors for gases such as carbon dioxide, methane (the gas used to heat homes) and carbon dioxide. Single electron transistors allow only one electron to travel through the device when switched on to form the electrical current. If the control gate is switched at a high frequency then the current through the device is simply the frequency times the charge on an electron and by counting the number of electrons, the current can be accurately measured. All such devices to date only work at low temperatures due to the small energy difference between the quantum states required for the transistor. I am proposing to make a single electron transistor which is far smaller than any previous reported device that will have large energies between the quantum states and operate at room temperature. Gas molecules absorb light at very specific wavelengths which in the mid-infrared part of the electromagnetic spectrum correspond to vibrational energy of the bonds which hold the atoms together to form the gas molecule. This provides a molecular fingerprint as each molecule only absorbs specific wavelengths which can therefore be used to identify the gas. Gas detectors already exist for carbon dioxide, carbon monoxide and methane gas by measuring the absorption of light at the molecular fingerprint wavelength but the sensitivity for small battery powered detectors in the home is at the level of parts per million. For many scientific, healthcare, industrial and security applications sensitivities require to be at least a thousand times better. To date systems for measuring at this accuracy are large, bulky and require large lasers. This proposal will use quantum technology to build a far smaller and cheaper chip scale gas detector with parts per billion sensitivity that could be integrated into mobile phones or used for battery power sensors. I am proposing to use the quantum nature of light to produce 2 individual packets of light called photons which will be at the same wavelength and at the same phase where the peaks and troughs of the waves are at the same points in space as the light travels through a waveguide. Heisenburg's uncertainty principle only allows us to measure the amplitude or the phase of the photons with a specific accuracy and the product is a constant. If we squeeze the phase of the light so that the accuracy in measuring the phase is reduced then we can measure the amplitude more accurately since it is only the product of the two that we cannot measure at a higher accuracy. This quantum approach of squeezing light allows far more sensitive measurements that are forbidden in classical measurement systems. The project brings together a range of UK companies, government agencies, standards laboratories and universities to deliver the portable current standard and the high sensitivity gas detector. I will be supplying demonstrators to a range of collaborators who will evaluate the performance with successful devices being transferred to UK companies to help develop next generation products. The project will also train 2 research associates and 2 PhD students in quantum technology.

This Hub accelerates progress towards a new "quantum era" by engineering small, high precision quantum systems, and linking them into a network to create the world's first truly scalable quantum computing engine. This new computing platform will harness quantum effects to achieve tasks that are currently impossible. The Hub is an Oxford-led alliance of nine universities with complementary expertise in quantum technologies including Bath, Cambridge, Edinburgh, Leeds, Strathclyde, Southampton, Sussex and Warwick. We have assembled a network of more than 25 companies (Lockheed-Martin, Raytheon BBN, Google, AMEX), government labs (NPL, DSTL, NIST) and SMEs (PureLiFi, Rohde & Schwarz, Aspen) who are investing resources and manpower. Our ambitious flagship goal is the Q20:20 engine - a network of twenty optically-linked ion-trap processors each containing twenty quantum bits (qubits). This 400 qubit machine will be vastly more powerful than anything that has been achieved to date, but recent progress on three fronts makes it a feasible goal. First, Oxford researchers recently discovered a way to build a quantum computer from precisely-controlled qubits linked with low precision by photons (particles of light). Second, Oxford's ion-trap researchers recently achieved a new world record for precision qubit control with 99.9999% accuracy. Third, we recently showed how to control photonic interference inside small silica chips. We now have an exciting opportunity to combine these advances to create a light-matter hybrid network computer that gets the 'best of both worlds' and overcomes long-standing impracticalities like the ever increasing complexity of matter-only systems, or the immense resource requirements of purely photonic approaches. Engineers and scientists with the hub will work with other hubs and partners from across the globe to achieve this. At present proof-of-principle experiments exist in the lab, and the 'grand challenge' is to develop compact manufacturable devices and components to build the Q20:20 engine (and to make it easy to build more). We have already identified more than 20 spin-offs from this work, ranging from hacker-proof communication systems and ultra-sensitive medical and military sensors to higher resolution imaging systems. Quantum ICT will bring great economic benefits and offer technical solutions to as yet unsolveable problems. Just as today's computers allow jet designers to test the aerodynamics of planes before they are built, a quantum computer will model the properties of materials before they've been made, or design a vital drug without the trial and error process. This is called digital quantum simulation. In fact many problems that are difficult using conventional computing can be enhanced with a 'quantum co-processor'. This is a hugely desirable capability, important across multiple areas of science and technology, so much so that even the prospect of limited quantum capabilities (e.g. D-Wave's device) has raised great excitement. The Q20:20 will be an early form of a verifiable quantum computer, the uncompromised universal machine that can ultimately perform any algorithm and scale to any size; the markets and impacts will be correspondingly far greater. In addition to computing there will be uses in secure communications, so that a 'trusted' internet becomes feasible, in sensing - so that we can measure to new levels of precision, and in new components - for instance new detectors that allow us to collect single photons. The hub will ultimately become a focus for an emerging quantum ICT industry, with trained scientists and engineers available to address the problems in industry and the wider world where quantum techniques will be bringing benefits. It will help form new companies, new markets, and grow the UK's knowledge economy.