1,282 research outputs found
The Atiyah class, Hochschild cohomology and the Riemann-Roch theorem
We develop a formalism involving Atiyah classes of sheaves on a smooth
manifold, Hochschild chain and cochain complexes. As an application we prove a
version of the Riemann--Roch theorem.Comment: 16 pages; added references, corrected typos and removed irrelevant
passage
A Lower Bound for Chaos on the Elliptical Stadium
The elliptical stadium is a plane region bounded by a curve constructed by
joining two half-ellipses by two parallel segments of equal length. The
billiard inside it, as a map, generates a two parameters family of dynamical
systems. It is known that the system is ergodic for a certain region of the
parameter space. In this work we study the stability of a particular family of
periodic orbits obtaining good bounds for the chaotic zone.Comment: 13 pages, LaTeX. 7 postscript low resolution figures included. High
resolution figures avaiable under request to [email protected]
Spectroscopy of Stellar-Like Objects Contained in the Second Byurakan Survey. I
The results of spectroscopic observations of 363 star-like objects from the
Second Byurakan Survey (SBS) are reported. This SBS's subsample has proven to
be a rich source of newly identified quasars, Seyfert type galaxies, degenerate
stars and hot subdwarfs. In the subsample here studied, we identified 35 new
QSOs, 142 White Dwarfs (WDs) the majority of which, 114 are of DA type, 55
subdwarfs (29 of which are sdB-type stars), 10 HBB, 16 NHB, 54 G-type and 25
F-type stars, two objects with composite spectra, four Cataclismic Variables
(CV), two peculiar emission line stars, 17 objects with continuous spectra, as
well as one planetary nebula. Among the 35 QSOs we have found two Broad
Absorption Line (BAL) QSOs, namely SBS 1423+500 and SBS 1435+500A. Magnitudes,
redshifts, and slit spectra for all QSOs, also some typical spectra of the
peculiar stars are presented. We estimate the minimum surface density of bright
QSOs in redshift range 0.3<z<2.2 to be 0.05 per sq. deg. for B<17.0 and 0.10
per sq. deg. for B<17.5.Comment: 22 pages, 3 tables, 4 figures, PASP in pres
A local ergodic theorem for non-uniformly hyperbolic symplectic maps with singularities
In this paper, we prove a criterion for the local ergodicity of non-uniformly
hyperbolic symplectic maps with singularities. Our result is an extension of a
theorem of Liverani and Wojtkowski.Comment: 35 page
Alien Registration- Markarian, Vartan (Lewiston, Androscoggin County)
https://digitalmaine.com/alien_docs/22326/thumbnail.jp
Low temperature dielectric relaxation study of aqueous solutions of diethylsulfoxide
In the present work, dielectric spectra of mixtures of diethylsulfoxide
(DESO) and water are presented, covering a concentration range of 0.2 - 0.3
molar fraction of DESO. The measurements were performed at frequencies between
1 Hz and 10 MHz and for temperatures between 150 and 300 K. It is shown that
DESO/water mixtures have strong glass-forming abilities. The permittivity
spectra in these mixtures reveal a single relaxation process. It can be
described by the Havriliak-Negami relaxation function and its relaxation times
follow the Vogel-Fulcher-Tammann law, thus showing the typical signatures of
glassy dynamics. The concentration dependence of the relaxation parameters,
like fragility, broadening, and glass temperature, are discussed in detail.Comment: 20 pages, 5 figure
A note on the symplectic structure on the space of G-monopoles
Let be a semisimple complex Lie group with a Borel subgroup . Let
be the flag manifold of . Let be the projective
line. Let . The moduli space of -monopoles of
topological charge (see e.g. [Jarvis]) is naturally identified with
the space of based maps from to of degree
. The moduli space of -monopoles carries a natural hyperk\"ahler
structure, and hence a holomorphic symplectic structure. We propose a simple
explicit formula for the symplectic structure on . It
generalizes the well known formula for (see e.g. [Atiyah-Hitchin]).
Let be a parabolic subgroup. The construction of the Poisson
structure on generalizes verbatim to the space of based maps
. In most cases the corresponding map is not an
isomorphism, i.e. splits into nontrivial symplectic leaves. These leaves
are explicilty described.Comment: v2: List of authors updated; v3: The formula for the symplectic form
corrected; v4: Notations changed; v5: A few more corrections: final versio
- …