5,334 research outputs found
Nonequilibrium Steady State of Photoexcited Correlated Electrons in the Presence of Dissipation
We present a framework to determine nonequilibrium steady states in strongly
correlated electron systems in the presence of dissipation. This is
demonstrated for a correlated electron (Falicov-Kimball) model attached to a
heat bath and irradiated by an intense pump light, for which an exact solution
is obtained with the Floquet method combined with the nonequilibrium dynamical
mean-field theory. On top of a Drude-like peak indicative of photometallization
as observed in recent pump-probe experiments, new nonequilibrium phenomena are
predicted to emerge, where the optical conductivity exhibits dip and kink
structures around the frequency of the pump light, a midgap absorption arising
from photoinduced Floquet subbands, and a negative attenuation (gain) due to a
population inversion.Comment: 5 pages, 3 figures, published versio
Operator product expansion and the short distance behavior of 3-flavor baryon potentials
The short distance behavior of baryon-baryon potentials defined through
Nambu-Bethe-Salpeter wave functions is investigated using the operator product
expansion. In a previous analysis of the nucleon-nucleon case, corresponding to
the SU(3) channels and , we argued that the potentials
have a repulsive core. A new feature occurs for the case of baryons made up of
three flavors: manifestly asymptotically attractive potentials appear in the
singlet and octet channels. Attraction in the singlet channel was first
indicated by quark model considerations, and recently been found in numerical
lattice simulations. The latter have however not yet revealed asymptotic
attraction in the octet channels; we give a speculative explanation for this
apparent discrepancy.Comment: 11 pages, 2 figure
Nutrient reserve difference between young and adult Short-tailed Shearwaters, Puffinus tenuirostris, before and after trans-equatorial migration
The Short-tailed Shearwater, Puffinus tenuirostris, is a trans-equatorial migrant, breeding in Tasmania and other parts of southeastern Australia
during the Austral summer and migrating to the northern North Pacific for the Boreal summer. Juveniles, in particular, suffer considerable
mortality during the migration. Body composition of juveniles and adults in terms of body mass, lipid content, pectoral muscle mass and
bone marrow content, before and after migration was investigated. Juveniles varied greatly in body composition pre- and post-migration
and took longer to recover their nutritional status than adults. Adults sustained a better body composition, showing a moderate decrease
in body fat upon arrival in the north and recovering their body mass and lipid supply during their stay. The lipid content of beachcast
bird carcasses (mean, 4 g) was the minimum necessary for cell membranes and was not metabolisable for energy. Pectoral muscle protein
remained high among birds under hyper-nutritional conditions, and decreased gradually at first as lipids decreased, and then rapidly at
late malnutritional stages when most lipids had been utilised for energy. Although adults sustained their nutritional status, the amount of
lipids in adults leaving the Tasmanian colony was insufficient to accomplish the long-distance migration, so post-breeding adults probably
first visited Antarctic waters to accumulate fat reserves before commencing their northward migration
Lambda(1405) as a Resonance in the Baryon-Meson Scattering Coupled to the q^3 State in a Quark Model
In order to describe Lambda(1405) as a resonance in the baryon-meson
scattering, we have investigated q^3-q qbar scattering system with the
flavor-singlet q^3 (0s)^2(0p) state (the Lambda^1 pole). The scattering is
treated by the quark cluster model (QCM). The Lambda^1 pole is treated as a
bound state embedded in the continuum. We found that the peak appears below the
N Kbar threshold in the spin one half, isospin 0 channel even if the mass of
the Lambda^1 pole is above the threshold. This peak disappears when the
coupling to the Lambda^1 pole is switched off. To use the observed hadron mass
in the kinetic part of QCM is also found to be important to reproduce a peak
just below the N Kbar threshold.Comment: 16 pages and 7 figure
Photoinduced insulator-metal transition in correlated electrons -- a Floquet analysis with the dynamical mean-field theory
In order to investigate photoinduced insulator-metal transitions observed in
correlated electron systems, we propose a new theoretical method, where we
combine a Floquet-matrix method for AC-driven systems with the dynamical
mean-field theory. The method can treat nonequilibrium steady states exactly
beyond the linear-response regime. We have applied the method to the
Falicov-Kimball model coupled to AC electric fields, and numerically obtained
the spectral function, the nonequilibrium distribution function and the
current-voltage characteristic. The results show that intense AC fields indeed
drive Mott-like insulating states into photoinduced metallic states in a
nonlinear way.Comment: 4 pages, 3 figures, Proceedings of LT2
Spin 3/2 Penta-quarks in anisotropic lattice QCD
A high-precision mass measurement for the pentaquark (5Q) Theta^+ in
J^P=3/2^{\pm} channel is performed in anisotropic quenched lattice QCD using a
large number of gauge configurations as N_{conf}=1000. We employ the standard
Wilson gauge action at beta=5.75 and the O(a) improved Wilson (clover) quark
action with kappa=0.1210(0.0010)0.1240 on a 12^3 \times 96 lattice with the
renormalized anisotropy as a_s/a_t = 4. The Rarita-Schwinger formalism is
adopted for the interpolating fields. Several types of the interpolating fields
with isospin I=0 are examined such as (a) the NK^*-type, (b) the
(color-)twisted NK^*-type, (c) a diquark-type. The chiral extrapolation leads
to only massive states, i.e., m_{5Q} \simeq 2.1-2.2 GeV in J^P=3/2^- channel,
and m_{5Q} = 2.4-2.6 GeV in J^P=3/2^+ channel. The analysis with the hybrid
boundary condition(HBC) is performed to investigate whether these states are
compact 5Q resonances or not. No low-lying compact 5Q resonance states are
found below 2.1GeV.Comment: 15 pages, 6 figures, 4 table
Relation between the separable and one-boson-exchange potential for the covariant Bethe-Salpeter equation
We investigate the relation between the rank I separable potential for the
covariant Bethe-Salpeter equation and the one-boson-exchange potential. After
several trials of the parameter choices, it turns out that it is not always
possible to reproduce the phase-shifts calculated from a single term of the
one-boson-exchange potential especially of the -exchange term,
separately by the rank I separable potential. Instead, it is shown that the
separable potential is useful to parameterize the total nucleon-nucleon
interaction.Comment: 10 pages, 8 figures, to appear in J.Phys.
Implementasi Strategi Pembelajaran Jigsaw Dan Peningkatan Pemahaman Pencegahan Demam Berdarah Dengue
: Implementation of Jigsaw Learning Strategy to Improve Understanding on DHF Prevention. The aim of this study is to know if: (1) the implementation of jigsaw Cooperative Learning Strategy (CLS) improved students' understanding about DHF prevention; (2) the implementation of modular jigsaw CLS improved students' understanding about DHF prevention; and (3) the implementation of modular jigsaw CLS improved students' understanding better than jigsaw CLS. This is an experimental study using the randomized pre - and posttest control group design and involving a total of 96 junior high school students di vided into 3 sample groups of 32 students each. From the results of data analyses, it can be concluded that jigsaw CLS and modular jigsaw CLS improved students' understanding about DHF prevention better than conventional learning while modular jigsaw CLS improved students' understanding about DHF prevention better than jigsaw CLS
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