116 research outputs found
A construction of Frobenius manifolds with logarithmic poles and applications
A construction theorem for Frobenius manifolds with logarithmic poles is
established. This is a generalization of a theorem of Hertling and Manin. As an
application we prove a generalization of the reconstruction theorem of
Kontsevich and Manin for projective smooth varieties with convergent
Gromov-Witten potential. A second application is a construction of Frobenius
manifolds out of a variation of polarized Hodge structures which degenerates
along a normal crossing divisor when certain generation conditions are
fulfilled.Comment: 46 page
Tailoring Dielectric Properties of Multilayer Composites Using Spark Plasma Sintering
A straightforward and simple way to produce well-densified ferroelectric ceramic composites with a full control of both architecture and properties using spark plasma sintering (SPS) is proposed. SPS main outcome is indeed to obtain high densification at relatively low temperatures and short treatment times thus limiting interdiffusion in multimaterials. Ferroelectric/dielectric (BST64/MgO/BST64) multilayer ceramic densified at 97% was obtained, with unmodified Curie temperature, a stack dielectric constant reaching 600, and dielectric losses dropping down to 0.5%, at room-temperature. This result ascertains SPS as a relevant tool for the design of functional materials with tailored properties
Theodor Storms Erstlingsnovelle «Marthe und ihre Uhr» (1847)
This article intends to fill the previous void of a thorough critical assessment and interpretive analysis of Theodor Stormâs first novellistic, albeit concise narrative of 1847. As an aesthetic and highly symbolic story, Martheâs seemingly timeless table clock bears some striking affinities with Eduard Mörikeâs objet dâart of 1838, his «Lampe». As an ardent admirer of his contemporary Mörike, Storm here lays his theoretical and artistic foundations for his major novellas of later years
Quasars Clustering at z approx 3 on Scales less sim 10 h^{-1} Mpc
We test the hypothesis whether high redshift QSOs would preferentially appear
in small groups or pairs, and if they are associated with massive, young
clusters. We carried out a photometric search for \Ly emitters on scales
Mpc, in the fields of a sample of 47 known
QSOs. Wide and narrow band filter color-magnitude diagrams were generated for
each of the fields. A total of 13 non resolved objects with a
significant color excess were detected as QSO candidates at a redshift similar
to that of the target. All the candidates are significantly fainter than the
reference QSOs, with only 2 of them within 2 magnitudes of the central object.
Follow-up spectroscopic observations have shown that 5, i.e., about 40% of the
candidates, are QSOs at the same redshift of the target; 4 are QSOs at
different z (two of them probably being a lensed pair at z = 1.47); 2
candidates are unresolved HII galaxies at z0.3; one unclassified and one
candidate turned out to be a CCD flaw. These data indicate that at least 10% of
the QSOs at z3 do have companions.
We have also detected a number of resolved, rather bright \Ly Emitter
Candidates. Most probably a large fraction of them might be bright galaxies
with [OII] emission, at z 0.3. The fainter population of our
candidates corresponds to the current expectations. Thus, there are no strong
indication for the existence of an overdensity of \Ly galaxies brighter than m
25 around QSOs at 3.Comment: 29 pages, 8 figures, tar gzip LaTex file, accepted to appear in Ap
Quantum deformations of associative algebras and integrable systems
Quantum deformations of the structure constants for a class of associative
noncommutative algebras are studied. It is shown that these deformations are
governed by the quantum central systems which has a geometrical meaning of
vanishing Riemann curvature tensor for Christoffel symbols identified with the
structure constants. A subclass of isoassociative quantum deformations is
described by the oriented associativity equation and, in particular, by the
WDVV equation. It is demonstrated that a wider class of weakly (non)associative
quantum deformations is connected with the integrable soliton equations too. In
particular, such deformations for the three-dimensional and
infinite-dimensional algebras are described by the Boussinesq equation and KP
hierarchy, respectively.Comment: Numeration of the formulas is correcte
Menelaus relation and Fay's trisecant formula are associativity equations
It is shown that the celebrated Menelaus relation and Fay's trisecant formula
similar to the WDVV equation are associativity conditions for structure
constants of certain three-dimensional algebra.Comment: Talk given at the Conference " Mathematics and Physics of Solitons
and Integrable Systems", Dijon, 28.6-2.7, 2009. Minor misprints correcte
ACS Observations of a Strongly Lensed Arc in a Field Elliptical
We report the discovery of a strongly lensed arc system around a field
elliptical galaxy in Hubble Space Telescope (HST) Advanced Camera for Surveys
(ACS) images of a parallel field observed during NICMOS observations of the HST
Ultra-Deep Field. The ACS parallel data comprise deep imaging in the F435W,
F606W, F775W, and F850LP bandpasses. The main arc is at a radius of 1.6 arcsec
from the galaxy center and subtends about 120 deg. Spectroscopic follow-up at
Magellan Observatory yields a redshift z=0.6174 for the lensing galaxy, and we
photometrically estimate z_phot = 2.4\pm0.3 for the arc. We also identify a
likely counter-arc at a radius of 0.6 arcsec, which shows structure similar to
that seen in the main arc. We model this system and find a good fit to an
elliptical isothermal potential of velocity dispersion
\kms, the value expected from the fundamental plane, and some external shear.
Several other galaxies in the field have colors similar to the lensing galaxy
and likely make up a small group.Comment: Accepted for publication in ApJ Letters. 10 pages, 3 figures. Figures
have been degraded to meet size limit; a higher resolution version and
addtional pictures available at http://acs.pha.jhu.edu/~jpb/UDFparc
Donagi-Markman cubic for the generalised Hitchin system
Donagi and Markman (1993) have shown that the infinitesimal period map for an algebraic completely integrable Hamiltonian system (ACIHS) is encoded in a section of the third symmetric power of the cotangent bundle to the base of the system. For the ordinary Hitchin system the cubic is given by a formula of Balduzzi and Pantev. We show that the Balduzzi\u2013Pantev formula holds on maximal rank symplectic leaves of the G-generalised Hitchin system
The structure of 2D semi-simple field theories
I classify all cohomological 2D field theories based on a semi-simple complex
Frobenius algebra A. They are controlled by a linear combination of
kappa-classes and by an extension datum to the Deligne-Mumford boundary. Their
effect on the Gromov-Witten potential is described by Givental's Fock space
formulae. This leads to the reconstruction of Gromov-Witten invariants from the
quantum cup-product at a single semi-simple point and from the first Chern
class, confirming Givental's higher-genus reconstruction conjecture. The proof
uses the Mumford conjecture proved by Madsen and Weiss.Comment: Small errors corrected in v3. Agrees with published versio
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