3,723 research outputs found
Construction of N = 2 Chiral Supergravity Compatible with the Reality Condition
We construct N = 2 chiral supergravity (SUGRA) which leads to Ashtekar's
canonical formulation. The supersymmetry (SUSY) transformation parameters are
not constrained at all and auxiliary fields are not required in contrast with
the method of the two-form gravity. We also show that our formulation is
compatible with the reality condition, and that its real section is reduced to
the usual N = 2 SUGRA up to an imaginary boundary term.Comment: 16 pages, late
Third-order integrable difference equations generated by a pair of second-order equations
We show that the third-order difference equations proposed by Hirota,
Kimura and Yahagi are generated by a pair of second-order difference
equations. In some cases, the pair of the second-order equations are equivalent
to the Quispel-Robert-Thomson(QRT) system, but in the other cases, they are
irrelevant to the QRT system. We also discuss an ultradiscretization of the
equations.Comment: 15 pages, 3 figures; Accepted for Publication in J. Phys.
Supersymmetry algebra in N = 1 chiral supergravity
We consider the supersymmetry (SUSY) transformations in the chiral Lagrangian
for supergravity (SUGRA) with the complex tetrad following the method
used in the usual SUGRA, and present the explicit form of the SUSY
trasformations in the first-order form. The SUSY transformations are generated
by two independent Majorana spinor parameters, which are apparently different
from the constrained parameters employed in the method of the 2-form gravity.
We also calculate the commutator algebra of the SUSY transformations on-shell.Comment: 10 pages, late
Canonical formulation of N = 2 supergravity in terms of the Ashtekar variable
We reconstruct the Ashtekar's canonical formulation of N = 2 supergravity
(SUGRA) starting from the N = 2 chiral Lagrangian derived by closely following
the method employed in the usual SUGRA. In order to get the full graded algebra
of the Gauss, U(1) gauge and right-handed supersymmetry (SUSY) constraints, we
extend the internal, global O(2) invariance to local one by introducing a
cosmological constant to the chiral Lagrangian. The resultant Lagrangian does
not contain any auxiliary fields in contrast with the 2-form SUGRA and the SUSY
transformation parameters are not constrained at all. We derive the canonical
formulation of the N = 2 theory in such a manner as the relation with the usual
SUGRA be explicit at least in classical level, and show that the algebra of the
Gauss, U(1) gauge and right-handed SUSY constraints form the graded algebra,
G^2SU(2)(Osp(2,2)). Furthermore, we introduce the graded variables associated
with the G^2SU(2)(Osp(2,2)) algebra and we rewrite the canonical constraints in
a simple form in terms of these variables. We quantize the theory in the
graded-connection representation and discuss the solutions of quantum
constraints.Comment: 19 pages, Latex, corrected some typos and added a referenc
General considerations of matter coupling with the self-dual connection
It has been shown for low-spin fields that the use of only the self-dual part
of the connection as basic variable does not lead to extra conditions or
inconsistencies. We study whether this is true for more general chiral action.
We generalize the chiral gravitational action, and assume that half-integer
spin fields are coupled with torsion linearly. The equation for torsion is
solved and substituted back into the generalized chiral action, giving
four-fermion contact terms. If these contact terms are complex, the imaginary
part will give rise to extra conditions for the gravitational and matter field
equations. We study the four-fermion contact terms taking spin-1/2 and spin-3/2
fields as examples.Comment: 16 pages, late
Minimal Off-Shell Version of N = 1 Chiral Supergravity
We construct the minimal off-shell formulation of N = 1 chiral supergravity
(SUGRA) introducing a complex antisymmetric tensor field and a
complex axial-vector field as auxiliary fields. The resulting algebra
of the right- and left-handed supersymmetry (SUSY) transformations closes off
shell and generates chiral gauge transforamtions and vector gauge
transformations in addition to the transformations which appear in the case
without auxiliary fields.Comment: 9 pages, late
Dynamic charge correlations near the Peierls transition
The quantum phase transition between a repulsive Luttinger liquid and an
insulating Peierls state is studied in the framework of the one-dimensional
spinless Holstein model. We focus on the adiabatic regime but include the full
quantum dynamics of the phonons. Using continuous-time quantum Monte Carlo
simulations, we track in particular the dynamic charge structure factor and the
single-particle spectrum across the transition. With increasing electron-phonon
coupling, the dynamic charge structure factor reveals the emergence of a charge
gap, and a clear signature of phonon softening at the zone boundary. The
single-particle spectral function evolves continuously across the transition.
Hybridization of the charge and phonon modes of the Luttinger liquid
description leads to two modes, one of which corresponds to the coherent
polaron band. This band acquires a gap upon entering the Peierls phase, whereas
the other mode constitutes the incoherent, high-energy spectrum with backfolded
shadow bands. Coherent polaronic motion is a direct consequence of quantum
lattice fluctuations. In the strong-coupling regime, the spectrum is described
by the static, mean-field limit. Importantly, whereas finite electron density
in general leads to screening of polaron effects, the latter reappear at half
filling due to charge ordering and lattice dimerization.Comment: 8 pages, 7 figures, final versio
N = 3 chiral supergravity compatible with the reality condition and higher N chiral Lagrangian density
We obtain N = 3 chiral supergravity (SUGRA) compatible with the reality
condition by applying the prescription of constructing the chiral Lagrangian
density from the usual SUGRA. The chiral Lagrangian density in
first-order form, which leads to the Ashtekar's canonical formulation, is
determined so that it reproduces the second-order Lagrangian density of the
usual SUGRA especially by adding appropriate four-fermion contact terms. We
show that the four-fermion contact terms added in the first-order chiral
Lagrangian density are the non-minimal terms required from the invariance under
first-order supersymmetry transformations. We also discuss the case of higher N
theories, especially for N = 4 and N = 8.Comment: 20 pages, Latex, some more discussions and new references added, some
typos corrected, accepted for publication in Physical Review
Parental Perception of the Children’s Weight Status in Indonesia
Background: The frequency of overweight among children in developing countries is increasing. Parents play a significant role in the successful prevention and treatment of overweight in their children. However, parents will be unable to take effective action against overweight if they cannot correctly perceive their children’s weight status.
Objectives: The aim of the study was to investigate parents’ perceptions of their children’s weight status and the factors associated with parental misperceptions about their children’s weight status.
Methods: In this cross-sectional study, a sample of 886 children aged 6 - 13 years and their fathers or mothers were selected using convenience sampling. Data were collected using a questionnaire about the subjects’ sociodemographic characteristics and the parents’ perceptions of their children’s weight status. The children’s anthropometric parameters were measured using standardized equipments. The chi-square test and logistic regression were used to analyze the data.
Results: Approximately 50% of the parents misperceived their children’s weight status, -4.29% overestimated, and 45.26% underestimated it. The frequency of weight status underestimation was high among the parents of overweight and normal weight children (47.65% and 55.08%, respectively). Logistic regression analysis revealed that the underestimation of weight status by parents was associated with the child’s body mass index (BMI) (odds ratio [OR]: 0.93 and 95% confidence interval [CI]: 0.89 - 0.97), the younger children (OR: 1.5, 95% CI: 1.13 - 1.99), a higher parental educational level (OR: 1.54, 95%CI: 1.02 - 2.33), and irregular BMI screening (OR: 1.34, 95%CI: 1.01 - 1.77).
Conclusions: Parents often have misperceptions about their children’s weight status. Nurses should help parents to correctly perceive their children’s weight status. This study also emphasizes on the need for periodic follow-up of BMI among children
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