42,763 research outputs found
Manin-Olshansky triples for Lie superalgebras
Following V. Drinfeld and G. Olshansky, we construct Manin triples (\fg,
\fa, \fa^*) such that \fg is different from Drinfeld's doubles of \fa for
several series of Lie superalgebras \fa which have no even invariant bilinear
form (periplectic, Poisson and contact) and for a remarkable exception.
Straightforward superization of suitable Etingof--Kazhdan's results guarantee
then the uniqueness of -quantization of our Lie bialgebras. Our examples
give solutions to the quantum Yang-Baxter equation in the cases when the
classical YB equation has no solutions. To find explicit solutions is a
separate (open) problem. It is also an open problem to list (\`a la
Belavin-Drinfeld) all solutions of the {\it classical} YB equation for the
Poisson superalgebras \fpo(0|2n) and the exceptional Lie superalgebra
\fk(1|6) which has a Killing-like supersymmetric bilinear form but no Cartan
matrix
Hot Spots on the Fermi Surface of Bi2212: Stripes versus Superstructure
In a recent paper Saini et al. have reported evidence for a pseudogap around
(pi,0) at room temperature in the optimally doped superconductor Bi2212. This
result is in contradiction with previous ARPES measurements. Furthermore they
observed at certain points on the Fermi surface hot spots of high spectral
intensity which they relate to the existence of stripes in the CuO planes. They
also claim to have identified a new electronic band along Gamma-M1 whose one
dimensional character provides further evidence for stripes. We demonstrate in
this Comment that all the measured features can be simply understood by
correctly considering the superstructure (umklapp) and shadow bands which occur
in Bi2212.Comment: 1 page, revtex, 1 encapsulated postscript figure (color
The Schwaigerian driver transfer technique and the Thevenin's and the Norton's theorem Final report
Graphical technique for analyzing series-parallel networks by rectangular diagrams in solving power distribution problem
Analytical Gradients for Projection-Based Wavefunction-in-DFT Embedding
Projection-based embedding provides a simple, robust, and accurate approach
for describing a small part of a chemical system at the level of a correlated
wavefunction method while the remainder of the system is described at the level
of density functional theory. Here, we present the derivation, implementation,
and numerical demonstration of analytical nuclear gradients for
projection-based wavefunction-in-density functional theory (WF-in-DFT)
embedding. The gradients are formulated in the Lagrangian framework to enforce
orthogonality, localization, and Brillouin constraints on the molecular
orbitals. An important aspect of the gradient theory is that WF contributions
to the total WF-in-DFT gradient can be simply evaluated using existing WF
gradient implementations without modification. Another simplifying aspect is
that Kohn-Sham (KS) DFT contributions to the projection-based embedding
gradient do not require knowledge of the WF calculation beyond the relaxed WF
density. Projection-based WF-in-DFT embedding gradients are thus easily
generalized to any combination of WF and KS-DFT methods. We provide numerical
demonstration of the method for several applications, including calculation of
a minimum energy pathway for a hydride transfer in a cobalt-based molecular
catalyst using the nudged-elastic-band method at the CCSD-in-DFT level of
theory, which reveals large differences from the transition state geometry
predicted using DFT.Comment: 15 pages, 4 figure
Canonical Charmonium Interpretation for Y(4360) and Y(4660)
In this work, we consider the canonical charmonium assignments for Y(4360)
and Y(4660). Y(4660) is good candidate of state, the
possibility of Y(4360) as a state is studied, and the
charmonium hybrid interpretation of Y(4360) can not be excluded completely. We
evaluate the leptonic widths, E1 transitions, M1 transitions and
the open flavor strong decays of Y(4360) and Y(4660). Experimental tests for
the charmonium assignments are suggested.Comment: 32 pages, 4 figure
Evolution of the Fermi surface with carrier concentration in Bi_2Sr_2CaCu_2O_{8+\delta}
We show, by use of angle-resolved photoemission spectroscopy, that underdoped
Bi_2Sr_2CaCu_2O_{8+\delta} appears to have a large Fermi surface centered at
(\pi,\pi), even for samples with a T_c as low as 15 K. No clear evidence of a
Fermi surface pocket around (\pi/2,\pi/2) has been found. These conclusions are
based on a determination of the minimum gap locus in the pseudogap regime T_c <
T < T^*, which is found to coincide with the locus of gapless excitations in
momentum space (Fermi surface) determined above T^*. These results suggest that
the pseudogap is more likely of precursor pairing rather than magnetic origin.Comment: 4 pages, revtex, 4 postscript color figure
Dynamical evolution of scalar perturbation in Ho\v{r}ava-Lifshitz black-hole spacetimes
We study the dynamical evolution of a massless scalar perturbation in the
Ho\v{r}ava-Lifshitz black-hole spacetimes with the coupling constants
, and , respectively. Our calculation
shows that, for the three cases, the scalar perturbations decay without any
oscillation in which the decay rate imprints the parameter of the
Ho\v{r}ava-Lifshitz black hole. The results are quite different from those in
the Schwarzschild AdS black hole and can help us understand more about the
Ho\v{r}ava-Lifshitz gravity.Comment: 14 pages, 5 figure
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