Devices based on Entanglement in Cold Arrays of Trapped Atoms

Quantum physics involves not only the physics of very small systems, or small amounts of energy, but also subtle correlations between particles and fields which result in entanglement. Creating large-scale arrays of entangled atoms for quantum applications is both highly topical and challenging. Quantum simulations, which involve quantum systems modelling other quantum systems, are just emerging as a powerful new tool of calculation, and yet quantum information processing (QIP) has many unrealized applications. In this context this proposal aims to transform the promising atom chip technology with new tools from quantum optics. We will design methods for entangling large numbers of atoms with applications to desirable and realizable quantum devices: e.g. high precision interferometers, motion sensors, realistic designs for large-scale quantum simulations, and quantum logic modules leading to quantum processors. Tools for controlling and trapping cold atoms in arrays will be formulated - and new designs for micro-structures that trap atoms above micro-fabricated surfaces will be made. After further commercial development the proposed devices have a number of end-user applications including rotation sensing and navigation, mineral and petroleum prospecting, decryption, and searching unsorted lists.

If we look beyond the immediate academic beneficiaries, then in the longer term (say 5-15 years), the outputs of the research may impact on society. These outputs include realizable designs for quantum devices which whilst not at the level of engineering drawings, are nevertheless intended to be realistic concepts, and which may, in a few cases, achieve proof-of-principle experimental demonstration during the life-time of the grant. High-technology companies are needed to exploit the plans and build such devices; the research work can help speed this kind of commercial development by making the opportunities clearer to those with a commercial interest. Publication of results on the web, in open access journals, and in popular media, will assist in this form of impact. In addition the University of Sussex has its own IP development company which can seek investors to help commercialize research. Several kinds of device are involved in this research. Cold atoms in traps can be used for interferometry and are sensitive to gravitational fields which could lead to applications such as sensors for gravimetric mapping or sensors for monitoring acceleration. The research proposal will investigate enhancement through the use of entangled states. Precision rotation sensors using compact atom chip technology would be attractive for new navigational instruments. Quantum information processing and quantum computing have received considerable attention in recent years. Should the technology come to fruition, we can envisage a dedicated processor, e.g. an atom chip in a small self-contained cell, embedded inside a larger conventional computer. The quantum processor would be responsible for particular tasks based on the algorithms that can be encoded on it. There are two striking examples: firstly, the Shor algorithm will enable the factorization of large numbers beyond what can be done with today's conventional computers. Since RSA encryption is based on the difficulty of performing this factorization, there is considerable interest in QIP from defence and intelligence agencies. Secondly, there is Grover's algorithm for searching an unsorted database. In this case the speed-up from the quantum algorithm is of interest to organisations holding vast amounts of data such as some government departments. Quantum simulations involve modelling a quantum system on another quantum system. The research in the proposal models lattice systems with obvious applications to the field of condensed matter. Ultimately this could impact on the public, for example, through the design of new materials such as high-Tc superconductors. The research results will be published and disseminated through conferences and the funded EPSRC UK Network for Research at the Interface between Cold-atom and Condensed Matter Physics.