46,138 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
Meeting update: faecal microbiota transplantation––bench, bedside, courtroom?
A group of stakeholders met, under the aegis of the British Society of Gastroenterology, to discuss the current landscape of faecal microbiota transplant- ation (FMT) within the UK and beyond. The meeting covered a wide range of topics, ranging from the practical aspects of establishing an FMT service and regu- latory issues relating to its delivery, to research implications and likely future directions
Overall properties of the Gaia DR1 reference frame
We compare quasar positions of the auxiliary quasar solution with ICRF2
sources using different samples and evaluate the influence on the {\it Gaia}
DR1 reference frame owing to the Galactic aberration effect over the
J2000.0-J20015.0 period. Then we estimate the global rotation between TGAS with
{\it Tycho}-2 proper motion systems to investigate the property of the {\it
Gaia} DR1 reference frame. Finally, the Galactic kinematics analysis using the
K-M giant proper motions is performed to understand the property of {\it Gaia}
DR1 reference frame. The positional comparison between the auxiliary quasar
solution and ICRF2 shows negligible orientation and validates the declination
bias of \mas~in {\it Gaia} quasar positions with respect to ICRF2.
Galactic aberration effect is thought to cause an offset \mas~of
the axis direction of {\it Gaia} DR1 reference frame. The global rotation
between TGAS and {\it Tycho}-2 proper motion systems, obtained by different
samples, shows a much smaller value than the claimed value \masyr. For
the Galactic kinematics analysis of the TGAS K-M giants, we find possible
non-zero Galactic rotation components beyond the classical Oort constants: the
rigid part \masyr~and the differential part
\masyr~around the axis of Galactic
coordinates, which indicates possible residual rotation in {\it Gaia} DR1
reference frame or problems in the current Galactic kinematical model.Comment: 6 pages, 1 figure. Accepted for publication in A&
Three realizations of quantum affine algebra
In this article we establish explicit isomorphisms between three realizations
of quantum twisted affine algebra : the Drinfeld ("current")
realization, the Chevalley realization and the so-called realization,
investigated by Faddeev, Reshetikhin and Takhtajan.Comment: 15 page
The absolute radiometric calibration of the advanced very high resolution radiometer
The measurement conditions are described for an intensive field campaign at White Sands Missile Range for the calibration of the AVHRRs on NOAA-9, NOAA-10 and NOAA-11, LANDSAT-4 TM and SPOT. Three different methods for calibration of AVHRRs by reference to a ground surface site are reported, and results from these methods are compared. Significant degradations in NOAA-9 and NOAA-10 AVHRR responsivities occurred since prelaunch calibrations were completed. As of February 1988, degradations in NOAA-9 AVHRR responsivities were on the order of 37 percent in channel and 41 percent in channel 2, and for the NOAA-10 AVHRR these degradations were 42 and 59 percent in channels 1 and 2, respectively
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
Quantum logic for control and manipulation of molecular ions using a frequency comb
Due to their rich level structure, molecules are well-suited for probing time
variation of fundamental constants, precisely measuring parity violation and
time-reversal non-invariance effects, studying quantum mechanical aspects of
chemical reactions, and implementing scalable quantum information processing
architectures. Molecular ions are particularly attractive for these
applications due to their long storage times and the near-perfect isolation
from environment that result in long coherence times required to achieve high
measurement precision and reduce systematic errors. However, the control of
molecular quantum states remains a challenge. Based on quantum logic
techniques, we propose a scheme for preparation, manipulation, and detection of
quantum states of single molecular ions. The scheme relies on coherent coupling
between internal and motional degrees of freedom of the molecular ion via a
frequency comb laser field, while detection and cooling of the motion of ions
is done via a co-trapped atomic ion.Comment: 5 pages, 3 figure
Chaotic to ordered state transition of cathode-sheath instabilities in DC glow discharge plasmas
Transition from chaotic to ordered state has been observed during the initial
stage of a discharge in a cylindrical dc glow discharge plasma. Initially it
shows a chaotic behavior but increasing the discharge voltage changes the
characteristics of the discharge glow and shows a period substraction of order
7 period 5 period 3 period 1 period i.e. the system goes to
single mode through odd cycle subtraction. On further increasing the discharge
voltage, the system goes through period doubling, like 1 period 2 period
4 period. On further increasing the voltage, the system goes to stable
state without having any oscillations.Comment: chathode-sheath, instabilities, chaos, period-subtraction,
bifurcation, dc-discharg
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