1,014 research outputs found
Estimation of matrices with row sparsity
An increasing number of applications is concerned with recovering a sparse
matrix from noisy observations. In this paper, we consider the setting where
each row of the unknown matrix is sparse. We establish minimax optimal rates of
convergence for estimating matrices with row sparsity. A major focus in the
present paper is on the derivation of lower bounds
Understanding the Random Displacement Model: From Ground-State Properties to Localization
We give a detailed survey of results obtained in the most recent half decade
which led to a deeper understanding of the random displacement model, a model
of a random Schr\"odinger operator which describes the quantum mechanics of an
electron in a structurally disordered medium. These results started by
identifying configurations which characterize minimal energy, then led to
Lifshitz tail bounds on the integrated density of states as well as a Wegner
estimate near the spectral minimum, which ultimately resulted in a proof of
spectral and dynamical localization at low energy for the multi-dimensional
random displacement model.Comment: 31 pages, 7 figures, final version, to appear in Proceedings of
"Spectral Days 2010", Santiago, Chile, September 20-24, 201
Localization on quantum graphs with random vertex couplings
We consider Schr\"odinger operators on a class of periodic quantum graphs
with randomly distributed Kirchhoff coupling constants at all vertices. Using
the technique of self-adjoint extensions we obtain conditions for localization
on quantum graphs in terms of finite volume criteria for some energy-dependent
discrete Hamiltonians. These conditions hold in the strong disorder limit and
at the spectral edges
Orbital imagery for planetary exploration. Volume 1 - Technical summary
Orbital imagery for planetary exploration - objectives, measurements, orbit selection results, and imaging sensor system scaling law
Orbital imagery for planetary exploration. Volume 2 - Definitions of scientific objectives
Orbital imagery for planetary exploration- objective outlines for planetary and atmospheric structure and composition, fields, and extraterrestrial lif
The weak localization for the alloy-type Anderson model on a cubic lattice
We consider alloy type random Schr\"odinger operators on a cubic lattice
whose randomness is generated by the sign-indefinite single-site potential. We
derive Anderson localization for this class of models in the Lifshitz tails
regime, i.e. when the coupling parameter is small, for the energies
.Comment: 45 pages, 2 figures. To appear in J. Stat. Phy
Lifshitz tails for alloy type models in a constant magnetic field
In this note, we study Lifshitz tails for a 2D Landau Hamiltonian perturbed
by a random alloy-type potential constructed with single site potentials
decaying at least at a Gaussian speed. We prove that, if the Landau level stays
preserved as a band edge for the perturbed Hamiltonian, at the Landau levels,
the integrated density of states has a Lifshitz behavior of the type
Prediction of neutron induced activation. Volume 2 - NAP, physical models and experimental validation Final report, May 14, 1964 - Jan. 31, 1966
Mathematical models for IBM 7094 computer program prediction of neutron induced activatio
Orbital imagery for planetary exploration. Volume 4 - Imaging sensor system scaling laws
Orbital imagery for planetary exploration - imaging sensor system scaling law
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