Quantum Materials and
DevicesThe QUEST research areas were chosen keeping in mind intrinsic importance, Divisional expertise, and long-term collaborational possibilities. The QUEST 2000 workshop was instrumental in forming external collaborational links and obtaining useful feedback on QUEST organizational and research plans. The philosophy underlying the QUEST research directions is outlined below.
Experiments in atomic optics have furnished the cleanest tests of quantum mechanics over the last several decades. The existence of precise theoretical predictions is a hallmark of these tests. As these experiments become ever more sophisticated and complex, one can envisage a passage from `toy' demonstrations to real applications. In contrast, condensed matter physics deals usually with more strongly coupled systems where a fully predictive theory is vastly more difficult. Nevertheless, experiments have become ever more refined and have now reached the point where they can be compared in quality to early atomic optics experiments. Thus the situation is ripe for active interaction and collaboration between these two fields: much of the theoretical development already carried out in quantum optics, such as continuous measurement and quantum control, can be taken over to condensed matter contexts, most notably in nanotechnology. As the scale size of the smallest structures that can be fabricated by lithographic techniques becomes smaller and smaller, dealing with quantum mechanics becomes inevitable. Since lithography is the only way we know to create very complex systems at reasonable cost, it follows that a fundamental and predictive understanding of quantum dynamics applicable to these systems (whether coherent or incoherent) will be required. The field is still relatively `theory-poor': LANL theoretical expertise is an excellent match with experiments both at the Lab and outside.
A broad range of theoretical expertise exists in T-Division in the above topics. Coupled with strong collaboration with experimentalists, both at LANL and outside, the aim of the QUEST project is to bring this to bear on the creation of new quantum science and technologies. Some of the QUEST research will be applicable to quantum computing, but this is not the key focus of QUEST.
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Quantum effects are ubiquitous in controlling the properties of materials. QUEST research in this area must, therefore, be highly selective. As a general policy, our aim is not to concentrate on historically well-established (though, perhaps, still not well-understood) areas but rather to focus on emerging new experimental arenas, techniques and tools, theoretical concepts, and device applications where quantum coherent phenomena play a crucial role. Long-term viability, however, remains a crucial test for inclusion in the QUEST research program.
Quantum State Control and
Engineering
The ability to create, control, and characterize arbitrary quantum states -- mixed or pure, entangled or separable -- is critical to various emergent quantum technologies. However, the present state of quantum technology is rather primitive. This is because (1) we still lack a comprehensive theory for understanding the effects of feedback upon the evolution of a quantum dynamical systems, and (2) technical complications brought by noise and decoherence, which can never truly be eliminated from real laboratory experiments. Although these are formidable issues to address, recent advances in fields such as atomic physics, NMR, quantum optics, and nano-electromechanics have begun to provide the tools required to surmount them.
Cold atom systems provide a new laboratory for the study of mesoscopic and macroscopic matter wave coherence. The flexibility and power of existing technology allows the creation and study of fundamentally novel superfluid structures (e.g., multiple condensates, multi-component and spinor condensates, and mutually coherent atom-molecule condensates) as well as quantum single-particle systems. Our effort in this area is to study the dynamics of these systems as a fundamental research problem and also to investigate their possible uses as experimental tools and probes.
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| Salman Habib / T-8 / LANL / habib@shiva.lanl.gov / revised February 02 |  |