Classically electrons in a three-dimensional solid can change their momentum in all possible directions. However, electrons in semiconductors can be manipulated so that they are constrained to move in lower dimensions. One of the perfect examples of such a system is a semiconductor heterostructure of GaAs/AlGaAs forming a plane of electrons, only a few nanometer thick, at its junction where electrons possessing quantised energy and freedom to change momentum in the plane. Such remarkable ensemble of non-interacting electrons is known as the two-dimensional electron gas (2DEG). The electrons in a 2DEG system are highly mobile and at low temperatures their motion is mainly scattering free due to the reduction in the interaction with lattice vibrations (phonons) and there is little impurity scattering. When the 2D electrons are electrostatically squeezed to form a narrow, 1D channel whose effective size is less than the electron mean free path for scattering then quantum phenomena associated with the electrons becomes resolved. In this situation, the energy of 1D electrons becomes quantised and discrete levels are formed. At a low carrier concentration of electrons, if the potential which is confining the 1D electrons is relaxed then electrons can arrange themselves into a periodic zig- zag manner forming a Wigner Crystal, named after Wigner who first predicted such a phenomenon in metal in 1936. Recently the distortion of a line of electrons into a zig-zag and then into two separate rows of electrons was observed and associated rich spin and charge phases. A very subtle change in confinement can result in two rows emerging from a zig-zag state which indicates that there is a narrow range where wavefunctions separate and form entangled states. Entanglement is a remarkable phenomenon in which a change in state of one electron will introduce a change in state of another. This amazing property forms the basis for quantum information processing with practical consequences related to quantum technologies, which will be investigated in this proposal. Another most important aspect of my Fellowship proposal is investigating the zig-zag regime or relaxed 1D system in search of fractional quantum states in the absence of a magnetic field. In the presence of a large magnetic field the energy of a 2DEG is quantized to form Landau levels which gave rise to two celebrated discoveries of the Integer and fractional quantum Hall effects in 1980 and 1982 respectively. Such unexpected revelations then pose a question whether fractional quantised states in the absence of any magnetic field in any lattice or topological insulators could ever be observed? However, there were no reports of observations of any fractional states without a magnetic field until the recent discovery of fractional charges of e/2 and e/4 arising from the relaxed zig-zag state in a Germanium-based 1D system. The proposal is inspired by this and the recent experimental finding of non-magnetic self-organised fractional quantum states in tradition GaAs based 1D quantum wires, which was completely unanticipated. The research aim is to introduce new insights, and new aspects of quantum physics, by exploiting the interaction effects in low-dimensional semiconductors by manipulating electron wavefunctions in a controllable manner to allow technological exploitation of basic quantum physics. The major challenges to be investigated: spin and charge manipulation, demonstrating electron entanglement and detection, mapping self-organised fractional states and their spin states, controlled manipulation and detection of hybrid fractional states and establishing if they are entangled. This research proposal opens up a new area in the quantum physics of condensed matter with the generation of Non-Abelian fractions which can be used in a Topological Quantum Computation scheme.

The last fifty years have seen spectacular progress in the ability to assemble materials with a precision of nanometers (a few atoms across). This nanofabrication ability is built upon the twin pillars of lithography and pattern transfer. A whole range of tools are used for pattern transfer. Lithography is a photographic process for the production of small structures in which structures are "drawn" in a thin radiation sensitive film. Then comes the pattern transfer step in which the shapes are transferred into a useful material, such as that of an active semiconductor device or a metal wire. Lithography is the key process used to make silicon integrated circuits, such as a microprocessor with eight billion working transistors, or a camera chip which is over two inches across. The manufacture of microprocessors is accomplished in large, dedicated factories which are limited to making one type of device. Also, normal lithography tools require the production of large, perfect and extremely expensive "negatives" so that it is only economical to use this technology to make huge numbers of identical devices. The applications of lithography are far broader than just making silicon chips, however. For example, large areas of small dots of material can be used to make cells grow in particular directions or to become certain cell types for use in regenerative medicine; The definition of an exquisitely precise diffraction grating on a laser allows it to produce the perfectly controlled wavelengths of light needed to make portable atomic clocks or to measure the tiny magnetic fields associated with the functioning of the brain; Lithography enables the direct manipulation of quantum states needed to refine the international standards of time and electrical current and may one day revolutionise computation; By controlling the size and shape of a material we can give it new properties, enabling the replacement of scarce strategic materials such as tellurium in the harvesting of waste thermal energy. This grant will enable the installation of an "electron-beam lithography" system in an advanced general-purpose fabrication laboratory. Electron beam lithography uses an electron beam rather than light to expose the resist and has the same advantages of resolution that an electron microscope has over a light microscope. This system will allow the production of the tiniest structures over large samples but does not need an expensive "negative" to be made. Instead, like a laser printer, the pattern to be written is defined in software, so that there is no cost associated with changing the shape if only one object of a particular shape is to be made. The electron beam lithography system is therefore perfect for making small things for scientific research or for making small numbers of a specialized device for a small company. The tool will be housed in a laboratory which allows the processing of the widest possible range of materials, from precious gem diamonds a few millimetres across to disks of exotic semiconductor the size of dinner plates. The tool will be used by about 200 people from all over the UK and the world. By running continuously the tool will be very inexpensive to use, allowing the power of leading-edge lithography to be used by anyone, from students to small businesses. The tool will be supported and operated by a large dedicated team of extremely experienced staff, so that the learning curve to applying the most advanced incarnation of the most powerful technology of the age will be reduced to a matter of a few weeks.