Theory of Electrons in Solids

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0099572ShamThe aim of this theoretical research is to contribute to the construction of fundamental devices in quantum information processing and computation, and in spin-enhanced optoelectronics. The research is planned on the theory of the basic physical processes involved in the realization of the quantum algorithms by means of laser manipulation of electrons and their spin degress of freedom in semiconductor nanostructures. A photon in the laser beam can excite an electron in a semiconductor nano-dot into a state known as an exciton. The circular polarization of the light can also give the exciton a specific spin. Here, the spin-polarized exciton is selected as the phsyical representation of the fundamental unit of quantum information, the qubit. Optical control of a single exciton addresses the qubit and optical control of two interacting excitons yields the operation of a quantum logic device. The research consists of (1) a computation of the energy structures of the multiexciton states; (2) a theory of the nonlinear optical spectra of the quantum dot under intense laser excitation as a diagnostic tool for the conditions of operations; (3) design of the optical processes for the operations of the basic devices; (4) a study of the environmental degradation of the quantum nature of the exciton (decoherence); and (5) test of the design by numerical simulations of the time series of operations to accomplish simple versions of key quantum algorithms.%%%The aim of this theoretical research is to contribute to the construction of fundamental devices in quantum information processing and computation, and in spin-enhanced optoelectronics. The research is planned on the theory of the basic physical processes involved in the realization of the quantum algorithms by means of laser manipulation of electrons and their spin degress of freedom in semiconductor nanostructures.***