39,168 research outputs found
Holomorphic curves in exploded manifolds: regularity
The category of exploded manifolds is an extension of the category of smooth
manifolds related to tropical geometry in which some adiabatic limits appear as
smooth families. This paper studies the dbar equation on variations of a given
family of curves in an exploded manifold. Roughly, we prove that the dbar
equation on variations of an exploded family of curves behaves as nicely as the
dbar equation on variations of a smooth family of smooth curves, even though
exploded families of curves allow the development of normal crossing or log
smooth singularities. The resulting regularity results are used in a series of
separate papers to construct Gromov Witten invariants for exploded manifolds.Comment: 52 pages. v2: The construction of Gromov Witten invariants has been
removed to another paper. v3: rewritten introduction, improved exposition.
v4, v5: improved exposition v6, v7: Minor improvements and some expanded
explanations, (including weakened hypothesis for Proposition 3.11), as
suggested by an anonymous referee of a different paper. Final version to
appear in Geometry and Topolog
Determining surface magnetization and local magnetic moments with atomic scale resolution
We propose a method to determine the direction of surface magnetization and
local magnetic moments on the atomic scale. The method comprises high
resolution scanning tunneling microscope experiments in conjunction with first
principles simulations of the tunneling current. The potential of the method is
demonstrated on a model system, antiferromagnetic Mn overlayers on W(110). We
expect that it will ultimately allow to study the detailed changes of magnetic
surface structures in the vicinity of dopants or impurities.Comment: Four pages (RevTeX) and five figures (EPS). For related papers see
http://cmmp.phys.ucl.ac.uk/~wah
Shearer's point process, the hard-sphere model and a continuum Lov\'asz Local Lemma
A point process is R-dependent, if it behaves independently beyond the
minimum distance R. This work investigates uniform positive lower bounds on the
avoidance functions of R-dependent simple point processes with a common
intensity. Intensities with such bounds are described by the existence of
Shearer's point process, the unique R-dependent and R-hard-core point process
with a given intensity. This work also presents several extensions of the
Lov\'asz Local Lemma, a sufficient condition on the intensity and R to
guarantee the existence of Shearer's point process and exponential lower
bounds. Shearer's point process shares combinatorial structure with the
hard-sphere model with radius R, the unique R-hard-core Markov point process.
Bounds from the Lov\'asz Local Lemma convert into lower bounds on the radius of
convergence of a high-temperature cluster expansion of the hard-sphere model.
This recovers a classic result of Ruelle on the uniqueness of the Gibbs measure
of the hard-sphere model via an inductive approach \`a la Dobrushin
Quantum mechanics: A new chapter?
We review the conceptual problems in quantum mechanics on a fundamental
level. It is shown that the proposed model of extended electrons and a clear
understanding of rotations in three dimensional space solve a large part of
these problems, in particular the problems related to the ontological status
and physical meaning of wavefunctions. It also solves the problem of
non-locality. The experimental results obtained in Yves Couder's group and
theoretical results by Gerdard Gr\"ossing indicate that the wave-like
distribution of trajectories of electrons in interference experiments are most
likely due to the quantized interactions leading to a discrete set of
transferred momenta. A separate experimental confirmation of this
interpretation for double-slit interferometry of photons has been given by the
group of Steinberg.Comment: 8 pages, article to appear in the Proceedings of the 6th Conference:
Quantum Theory: Reconsideration of Foundations, June 11-14 2012 in Vaexjoe,
Swede
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