726 research outputs found
Analytic Perturbation Theory and Renormalization Analysis of Matter Coupled to Quantized Radiation
For a large class of quantum mechanical models of matter and radiation we
develop an analytic perturbation theory for non-degenerate ground states. This
theory is applicable, for example, to models of matter with static nuclei and
non-relativistic electrons that are coupled to the UV-cutoff quantized
radiation field in the dipole approximation. If the lowest point of the energy
spectrum is a non-degenerate eigenvalue of the Hamiltonian, we show that this
eigenvalue is an analytic function of the nuclear coordinates and of
,  being the fine structure constant. A suitably chosen
ground state vector depends analytically on  and it is twice
continuously differentiable with respect to the nuclear coordinates.Comment: 47 page
A vanishing theorem for operators in Fock space
We consider the bosonic Fock space over the Hilbert space of transversal
vector fields in three dimensions. This space carries a canonical
representation of the group of rotations. For a certain class of operators in
Fock space we show that rotation invariance implies the absence of terms which
either create or annihilate only a single particle. We outline an application
of this result in an operator theoretic renormalization analysis of Hamilton
operators, which occur in non-relativistic qed.Comment: 14 page
Ranking News-Quality Multimedia
News editors need to find the photos that best illustrate a news piece and
fulfill news-media quality standards, while being pressed to also find the most
recent photos of live events. Recently, it became common to use social-media
content in the context of news media for its unique value in terms of immediacy
and quality. Consequently, the amount of images to be considered and filtered
through is now too much to be handled by a person. To aid the news editor in
this process, we propose a framework designed to deliver high-quality,
news-press type photos to the user. The framework, composed of two parts, is
based on a ranking algorithm tuned to rank professional media highly and a
visual SPAM detection module designed to filter-out low-quality media. The core
ranking algorithm is leveraged by aesthetic, social and deep-learning semantic
features. Evaluation showed that the proposed framework is effective at finding
high-quality photos (true-positive rate) achieving a retrieval MAP of 64.5% and
a classification precision of 70%.Comment: To appear in ICMR'1
Ground state properties in non-relativistic QED
We discuss recent results concerning the ground state of non-relativistic
quantum electrodynamics as a function of a magnetic coupling constant or the
fine structure constant, obtained by the authors in [12,13,14].Comment: 6 Pages, contribution to the Proceedings of the Conference QMath 11
  held in Hradec Kralove (Czechia) in September 201
Anderson Localization at Band Edges for Random Magnetic Fields
We consider a magnetic Schr\"odinger operator in two dimensions. The magnetic
field is given as the sum of a large and constant magnetic field and a random
magnetic field. Moreover, we allow for an additional deterministic potential as
well as a magnetic field which are both periodic. We show that the spectrum of
this operator is contained in broadened bands around the Landau levels and that
the edges of these bands consist of pure point spectrum with exponentially
decaying eigenfunctions. The proof is based on a recent Wegner estimate
obtained in \cite{EH2} and a multiscale analysis
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