Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"Anderson model."”.
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Valence transition and superconductivity in the extended periodic Anderson model
In this thesis, an extended periodic Anderson model with an additional local Coulomb repulsion U f c between localized f electrons and conduction electrons is investigated by use of the projector-based renormalization method (PRM). First, it is shown that the model in one dimension shows a valence …
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Well-Posedness Threshold and Moment Asymptotics of the Parabolic Anderson Model on Riemannian Manifolds
The subject of this thesis is the parabolic Anderson model, the linear multiplicative stochastic heat equation. We consider the equation on Riemannian manifolds to study how geometry and topology can affect interesting properties of the solution. We focus on two topics: well-posedness and large …
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Quantum evolution: The case of weak localization for a 3D alloy-type Anderson model and application to Hamiltonian based quantum computation
… phenomena from a microscopic point of view. Anderson localization, named after physicist P. W. Anderson, states that disorder in a crystal can cause non-spreading of wave packets, which is one possible mechanism (at single electron level) to explain metalinsulator transitions. The theory of …
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SPDEs with Infinite-Variance Lévy Noise
… Lévy noise, which includes the Parabolic Anderson Model (PAM) and the Hyperbolic Anderson Model (HAM). Specifically, we demonstrate the existence of solutions for SPDEs driven by symmetric α-stable Lévy noise. Using the Lepage representation of the noise and techniques borrowed from the …
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Dormancy in spatial population models in random environments
This thesis introduces spatial models for populations with dormancy in random environments. The models are formulated as continuous-time two-type branching random walks, where individuals switch between active and dormant states. We consider two scenarios: one where the switching rates are …
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Método atômico para o modelo de Anderson em presença de um campo magnético externo.
We develop the atomic method (AM) for the Anderson impurity model under an external magnetic field. The Green s functions (GF) representing the exact solution of the impurity problem is written in terms of an effective cumulant, that in the atomic method is replaced by the atomic cumulant obtained …
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The study of many-electron systems
… interacting systems. Two important many-particle models, the Anderson model and the Hubbard model, and their electromagnetic properties have been investigated in many parameter regimes, and applied to physical systems. An Anderson single-impurity model Hamiltonian based calculation of the magnetic …
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Application of RMT-RNN improved decomposition onto defected system
… the distribution of eigenvalues in the Anderson Model. RMT has proven to work well when looking for the transport properties in slightly defect system. Systems with larger disorder require to take in account of the changes in eigenvectors as well. Hence, combined with parallelizable …
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Orbital Level Understanding of Adsorbate-Surface Interactions in Metal Nanocatalysis
… We also employ Bayesian learning and the Newns-Anderson model to advance the fundamental understanding of adsorbate-surface interactions on metal nanocatalysts, paving the path toward adsorbate-specific tuning of catalysis.
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Localization and delocalization in two-dimensional quantum percolation
… percolation is one of several disorder-only models that address the question of whether conduction, or more generally, delocalization, is possible in two dimensional disordered systems. Whether quantum percolation exhibits a delocalization-localization phase transition in two dimensions is an …
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Studies of and methods for electronic properties of large chemical systems
In this thesis, we explore various approaches to modeling electronic properties of large chemical systems, a challenge for theoretical and computational chemistry. We first model experimental systems with conventional electronic structure by excerpting a region of interest: a few amino acids near …
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Coherent Transport of Matter Waves in Disordered Optical Potentials
… studied numerically in the framework of the Anderson model. The relevant transport parameters in the configuration average over many different realizations of the speckle potential are then determined analytically, using self-consistent diagrammatic perturbation techniques. This allows to …
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Open quantum system dynamics for describing state transfer
… for the simulation of the one-dimensional Fano-Anderson model. This algorithm was proposed for a liquid-state NMR device. We examine models of noise in the evolution using different initial states in the original model. We also add interacting spins to simulate realistic situation where an …
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Studies in random Ising spin systems
… on the twodimensional short-ranged random-bond model and the three-dimensional random-field model. The phenomenological renormalization group and the transfer-matrix method are generalized to random systems and applied to the random-bond Ising model, also called the Edwards-Anderson spin-glass …
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Effects of doping on the electronic properties of niobium triselenide
… moment may be qualitatively described by the Anderson modeL A broad Conduction Electron Spin Resonance(CESR) is observed in undoped, Ta doped, and V doped samples; we explain the temperature dependence of the resonance intensity, g-shift, and linewidth result from modification of the non-CDW …
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Eigenvalues and low energy eigenvectors of quantum many-body systems
… from free probability theory in context of the Anderson model. The second part is devoted to ground states and gap of QMBS. I first give the necessary background on frustration free Hamiltonians, real and imaginary time evolution of quantum spin systems on a line within MPS representation and …
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Transport properties of quantum dot molecules and electronic structure of graphene quantum dot qubits
… many-body equation of motion method for Hubbard-Anderson model to study non-equilibrium charge and thermal transport properties of QDMs connected to metallic electrodes in the Coulomb blockade regime. An exterior algebra method is developed to construct the equation of motion computationally, …
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Application of renormalization-group techniques to random magnetic systems
… the Wilson-Fisher E-expansion to random n-vector models; Khme1'nitsky discovered that the random Ising model (n = 1) possessed a ""random"" fixed point of 0(squareroot(e)). This fixed point was found to have one marginal and one irrelevant operator. We have investigated the stability of this fixed …
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Time Reparametrization Symmetry and Spatial-Temporal Fluctuations in Glasses
… has been shown to be present in the Edwards-Anderson model of spin glasses and in the mean field equations of p-spin models. We study time reparametrization symmetry in p-spin models of arbitrary interaction range. Starting from the Martin-Siggia-Rose generating functional, we analytically …
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