NER: Decoherence and Quantum Computing in Nanoengineered Semiconductor Devices

Clarkson University, Potsdam NY

Investigators

Abstract

This proposal was received in response to NSE, NSF-0019. The PI propose to develop solid-state many-body modeling techniques for evaluation of decoherence, relaxation, and interaction properties of nuclear and impurity-bound electron spins in nanoengineered semiconductor materials. Modern layered semiconductor heterostructures and quantum wells, involving strained alloys, band-structure and g-factor engineering, have been utilized in recent designs for realizations of quantum information processing (quantum computing). Quantum bits (qubits) are the nuclear or bound-electron spins of precisely positioned, isotopically selected impurity atoms. Recently, it has been demonstrated that such structures can be actually made by advanced MBE and lithography techniques. Consideration of polarized spins in semiconductor materials has become also of central interest owing to new experimental developments including optically pumped NMR detection of polarization and coupling of spin-polarized electronic behavior to nuclear polarization. Several experimental efforts are on the way to measure single spins and realize initial few-qubit semiconductor spin-based quantum computation. There has been only limited advancement in theoretical modeling and estimation of spin interactions, control, relaxation, and decoherence. The consideration of decoherence, in particular, is a new dimension in solid-state semiconductor research, not considered in earlier studies. The field is widely open with the open questions being not only how, but what to calculate, and with many conceptual issues remaining to be clarified, in relation to coherent quantum dynamics. PIs emphasis will be on developing and applying theoretical techniques to study all the aspects of quantum dynamics in such systems, from control to decoherence, by field-theoretical many-body solid-state techniques. It is hoped that success of this exploratory project will lead to new breakthroughs in an explosively growing field of semiconductor research and technology development.