1,627 research outputs found
Correlation Functions in Two-Dimensional Dilaton Gravity
The Liouville approach is applied to the quantum treatment of the dilaton
gravity in two dimensions. The physical states are obtained from the BRST
cohomology and correlation functions are computed up to three-point functions.
For the case (i.e., without matter), the cosmological term operator is
found to have the discrete momentum that plays a special role in the
Liouville gravity. The correlation functions for arbitrary numbers of operators
are found in the case, and are nonvanishing only for specific
``chirality'' configurations.Comment: 14 pages, TIT/HEP-204, STUPP-92-13
Derived bracket construction and Manin products
We will extend the classical derived bracket construction to any algebra over
a binary quadratic operad. We will show that the derived product construction
is a functor given by the Manin white product with the operad of permutation
algebras. As an application, we will show that the operad of prePoisson
algebras is isomorphic to Manin black product of the Poisson operad with the
preLie operad. We will show that differential operators and Rota-Baxter
operators are, in a sense, Koszul dual to each other.Comment: This is the final versio
On why the Iron K-shell absorption in AGN is not a signature of the local Warm/Hot Intergalactic Medium
We present a comparison between the 2001 XMM-Newton and 2005 Suzaku
observations of the quasar, PG1211+143 at z=0.0809. Variability is observed in
the 7 keV iron K-shell absorption line (at 7.6 keV in the quasar frame), which
is significantly weaker in 2005 than during the 2001 XMM-Newton observation.
From a recombination timescale of <4 years, this implies an absorber density
n>0.004 particles/cm3, while the absorber column is 5e22<N_H <1 1e24
particles/cm2. Thus the sizescale of the absorber is too compact (pc scale) and
the surface brightness of the dense gas too high (by 9-10 orders of magnitude)
to arise from local hot gas, such as the local bubble, group or Warm/Hot
Intergalactic Medium (WHIM), as suggested by McKernan et al. (2004, 2005).
Instead the iron K-shell absorption must be associated with an AGN outflow with
mildly relativistic velocities. Finally we show that the the association of the
absorption in PG1211+143 with local hot gas is simply a coincidence, the
comparison between the recession and iron K absorber outflow velocities in
other AGN does not reveal a one to one kinematic correlation.Comment: accepted for publication in MNRAS LETTERS. 5 pages, 4 figure
Extended supersymmetry and its reduction on a circle with point singularities
We investigate -extended supersymmetry in one-dimensional quantum
mechanics on a circle with point singularities. For any integer ,
supercharges are explicitly constructed in terms of discrete transformations,
and a class of singularities compatible with supersymmetry is clarified. In our
formulation, the supersymmetry can be reduced to -extended supersymmetry for
any integer . The degeneracy of the spectrum and spontaneous supersymmetry
breaking are also studied.Comment: 36 pages, 5 figures, 2 table
Spectral properties on a circle with a singularity
We investigate the spectral and symmetry properties of a quantum particle
moving on a circle with a pointlike singularity (or point interaction). We find
that, within the U(2) family of the quantum mechanically allowed distinct
singularities, a U(1) equivalence (of duality-type) exists, and accordingly the
space of distinct spectra is U(1) x [SU(2)/U(1)], topologically a filled torus.
We explore the relationship of special subfamilies of the U(2) family to
corresponding symmetries, and identify the singularities that admit an N = 2
supersymmetry. Subfamilies that are distinguished in the spectral properties or
the WKB exactness are also pointed out. The spectral and symmetry properties
are also studied in the context of the circle with two singularities, which
provides a useful scheme to discuss the symmetry properties on a general basis.Comment: TeX, 26 pages. v2: one reference added and two update
Leibniz 2-algebras and twisted Courant algebroids
In this paper, we give the categorification of Leibniz algebras, which is
equivalent to 2-term sh Leibniz algebras. They reveal the algebraic structure
of omni-Lie 2-algebras introduced in \cite{omniLie2} as well as twisted Courant
algebroids by closed 4-forms introduced in \cite{4form}.
We also prove that Dirac structures of twisted Courant algebroids give rise
to 2-term -algebras and geometric structures behind them are exactly
-twisted Lie algebroids introduced in \cite{Grutzmann}.Comment: 22 pages, to appear in Comm. Algebr
Quantum Analogy of Poisson Geometry, Related Dendriform Algebras and Rota-Baxter Operators
We will introduce an associative (or quantum) version of Poisson structure
tensors. This object is defined as an operator satisfying a "generalized"
Rota-Baxter identity of weight zero. Such operators are called generalized
Rota-Baxter operators. We will show that generalized Rota-Baxter operators are
characterized by a cocycle condition so that Poisson structures are so. By
analogy with twisted Poisson structures, we propose a new operator "twisted
Rota-Baxter operators" which is a natural generalization of generalized
Rota-Baxter operators. It is known that classical Rota-Baxter operators are
closely related with dendriform algebras. We will show that twisted Rota-Baxter
operators induce NS-algebras which is a twisted version of dendriform algebra.
The twisted Poisson condition is considered as a Maurer-Cartan equation up to
homotopy. We will show the twisted Rota-Baxter condition also is so. And we
will study a Poisson-geometric reason, how the twisted Rota-Baxter condition
arises.Comment: 18 pages. Final versio
Distillation of Liquid Xenon to Remove Krypton
A high performance distillation system to remove krypton from xenon was
constructed, and a purity level of Kr/Xe = was
achieved. This development is crucial in facilitating high sensitivity low
background experiments such as the search for dark matter in the universe.Comment: 15 pages, 11 figure
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