Browsing by Autor "Neil F. Johnson"

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Energy Conversion in Purple Bacteria Photosynthesis
(2012) Felipe Caycedo‐Soler; F. J. Rodríguez; Luis Quiroga; Guannan Zhao; Neil F. Johnson
The study of how photosynthetic organisms convert light offers insight not only into nature's evolutionary process, but may also give clues as to how best to design and manipulate artificial photosynthetic systems -- and also how far we can drive natural photosynthetic systems beyond normal operating conditions, so that they can harvest energy for us under otherwise extreme conditions. In addition to its interest from a basic scientific perspective, therefore, the goal to develop a deep quantitative understanding of photosynthesis offers the potential payoff of enhancing our current arsenal of alternative energy sources for the future. In the following Chapter, we consider the trade-off between dynamics, structure and function of light harvesting membranes in Rps. Photometricum purple bacteria, as a model to highlight the priorities that arise when photosynthetic organisms adapt to deal with the ever-changing natural environment conditions.
Exactly solvable model of interacting particles in a quantum dot
(American Physical Society, 1991) Neil F. Johnson; M. C. Payne
A simple, yet physically reasonable, model is presented which describes an arbitrary number of interacting particles in a quantum dot. Exact analytic expressions are obtained for the energy spectrum as a function of particle number and magnetic field.
Exactly solvable model of interacting particles in a quantum dot
(Elsevier BV, 1992) Neil F. Johnson; M. C. Payne
Quantum information processing in semiconductor nanostructures
(Cornell University, 2000) John H. Reina; Luis Quiroga; Neil F. Johnson
A major question for condensed matter physics is whether a solid-state quantum computer can ever be built. Here we discuss two different schemes for quantum information processing using semiconductor nanostructures. First, we show how optically driven coupled quantum dots can be used to prepare maximally entangled Bell and Greenberger-Horne-Zeilinger states by varying the strength and duration of selective light pulses. The setup allows us to perform an all-optical generation of the quantum teleportation of an excitonic state in an array of coupled quantum dots. Second, we give a proposal for reliable implementation of quantum logic gates and long decoherence times in a quantum dots system based on nuclear magnetic resonance (NMR), where the nuclear resonance is controlled by the ground state transitions of few-electron QDs in an external magnetic field. The dynamical evolution of these systems in the presence of environmentally-induced decoherence effects is also discussed.