188 research outputs found

    Dynamics of Nonequilibrium Deposition with Diffusional Relaxation

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    Models of adhesion of extended particles on linear and planar substrates are of interest in interpreting surface deposition in colloid, polymer, and certain biological systems. An introduction is presented to recent theoretical advances in modeling these processes. Effects of diffusional relaxation are surveyed in detail, including results obtained by analytical, large-scale numerical, mean-field and scaling approaches.Comment: Review article to appear in Annual Reviews in Computational Physics; 24 pages in plain TeX + 4 PostScript figure

    Topics in Quantum Dynamics and Coherence for Quantum Information Processing

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    We outline selected trends and results in theoretical modeling of quantum systems in support of the developing research field of quantum information processing. The resulting modeling tools have been applied to semiconductor materials and nanostructures that show promise for implementation of coherent, controlled quantum dynamics at the level of registers of several quantum bits (qubits), such as spins. Many-body field-theoretical techniques have been utilized to address a spectrum of diverse research topics. Specifically, the theory of decoherence and more generally the origin and effects of quantum noise and the loss of entanglement in quantum dynamics of qubits and several-qubit registers has been advanced. Qubit coupling mechanisms via the indirect exchange interaction have been investigated, and quantum computing designs have been evaluated for scalability. We outline general and specific research challenges, the solution of which will advance the field of modeling "open quantum systems" to further our understanding of how environmental influences affect quantum coherence and its loss during quantum dynamics

    Initial Decoherence of Open Quantum Systems

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    We present a new short-time approximation scheme for evaluation of decoherence. At low temperatures, the approximation is argued to apply at intermediate times as well. It then provides a tractable approach complementary to Markovian-type approximations, and is appropriate for evaluation of deviations from pure states in quantum computing models.Comment: 24 pages in plain Te

    Exact Results for 1D Conserved Order Parameter Model

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    Recent exact results for a particle-exchange model on a linear lattice, with only irreversible moves reducing the local energy allowed, are reviewed. This model describes a zero-temperature Kawasaki-type phase separation process which reaches a frozen, initial-condition-dependent state at large times.Comment: nine pages, plain Te

    Fluctuating Interfaces, Surface Tension, and Capillary Waves: An Introduction

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    We present an introduction to modern theories of interfacial fluctuations and the associated interfacial parameters: surface tension and surface stiffness, as well as their interpretation within the capillary wave model. Transfer matrix spectrum properties due to fluctuation of an interface in a long-cylinder geometry are reviewed. The roughening transition and properties of rigid interfaces below the roughening temperature in 3d lattice models are surveyed with emphasis on differences in fluctuations and transfer matrix spectral properties of rigid vs. rough interfaces.Comment: 21 page
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