Coherent Nanotechnology Quantum Devices for Information Processing

North Carolina State University, Raleigh NC

Investigators

Abstract

In a one-year small grant for exploratory research (SGER) granted by the ECS Division of NSF, we have explored new concepts for coherent quantum effects in nanotechnology devices. We have conceived of several new solid-state devices based on coupled coherent quantum phenomena that are potentially useful for computing and communications, and investigated their practicality through theoretical studies. With this initial success, we now propose to continue these studies with a more extensive and precise analysis of the phenomena and to initiate a coupled experimental program to show feasibility. The nanotechnology structure that shows most promise for a quantum computer is based on the spin of exchange coupled electrons trapped in an array of gated quantum dots fabricated in either III-V or silicon. The proposed quantum computer is capable of 10 5 operations within the coherence time at a two-qubit operation rate at 10 8 Hz. It is readily scalable to a large number of elements, on the order of ~10 6 qubits, and electrically reconfigurable utilizing a planar architecture. This device is unquestionably manufacturable using technology enabled by the 70-nm technology node as specified in the "International Technology Roadmap for Semiconductors, 1999 Edition". We have established collaborations with industry that wish to take advantage of this nanotechnology once we have shown feasibility. To fully examine the potential of our concepts, we propose to conduct a comprehensive study by analyzing the physical parameters of the devices to generate the desired energy structure and coupling strength among neighboring device elements, by investigating the limitations to coherence, and by simulating the operation of the device to operate it as a quantum computer. We further propose to undertake an experimental program to fabricate and test elementary prototypes of these devices to demonstrate feasibility. Collaboration between the theoretical and experimental studies should result in a nano-device structure that is technically interesting and potentially important for commercial use. This research will be coupled to an educational program that provides interdisciplinary research for graduate students and for the development of courses that introduce quantum information processes at the graduate level within the Electrical and Computer Engineering Department at North Carolina State University.