8,949 research outputs found
Characteristic length of a Holographic Superconductor with -wave gap
After the discovery of the -wave and -wave holographic superconductors,
holographic models of -wave superconductor have also been constructed
recently. We study analytically the perturbation of the dual gravity theory to
calculate the superconducting coherence length of the -wave
holographic superconductor near the superconducting phase transition point. The
superconducting coherence length divergents as near
the critical temperature . We also obtain the magnetic penetration depth
by adding a small external homogeneous magnetic
field. The results agree with the -wave and -wave models, which are also
the same as the Ginzburg-Landau theory.Comment: last version, 10 pages, accepted by PR
Revisiting mixing in QCD sum rules
We investigate the mixing caused by the flavor
symmetry breaking. The mixing angle is expressed by a matrix
element induced by the operators that breaks flavor symmetry. The QCD
contribution to this matrix element is assumed to be dominated and calculated
by QCD sum rules. A three-point correlation function is defined and handled
both at the hadron and quark-gluon levels. The quark-gluon level calculation is
based on operator product expansion up to dimension-5 condensates. A detailed
numerical analysis is performed to determine the Borel parameters, and the
obtained mixing angle is or
.Comment: 14 pages, 7 figures and 1 tabl
Standard metabolic rate predicts growth trajectory of juvenile Chinese crucian carp (Carassius auratus) under changing food availability
Phenotypic traits vary greatly within populations and can have a significant influence on aspects of performance. The present study aimed to investigate the effects of individual variation in standard metabolic rate (SMR) on growth rate and tolerance to food-deprivation in juvenile crucian carp (Carassius auratus) under varying levels of food availability. To address this issue, 19 high and 16 low SMR (individuals were randomly assigned to a satiation diet for 3 weeks, whereas another 20 high and 16 low SMR individuals were assigned to a restricted diet (approximately 50% of satiation) for the same period. Then, all fish were completely food-deprived for another 3 weeks. High SMR individuals showed a higher growth rate when fed to satiation, but this advantage of SMR did not exist in food-restricted fish. This result was related to improved feeding efficiency with decreased food intake in low SMR individuals, due to their low food processing capacity and maintenance costs. High SMR individuals experienced more mass loss during food-deprivation as compared to low SMR individuals. Our results here illustrate context-dependent costs and benefits of intraspecific variation in SMR whereby high SMR individuals show increased growth performance under high food availability but had a cost under stressful environments (i.e., food shortage)
QED contributions to the mixing
We explore the QED corrections to the mixing within
the framework of light-front quark model (LFQM) in the three-quark picture.
After explicitly investigating the relation between the
mixing and the flavor and heavy quark symmetry breaking, we
derive the QED contributions to the mixing angle. Numerical results indicate
the QED contribution is smaller than the one from the mass difference between
the strange and up/down quark provided by a recent Lattice QCD analysis. Adding
these contributions together we find that at this stage the
mixing is small and still incapable to account for the
large symmetry breaking in the semi-leptonic decays.Comment: 7 pages, 4figure
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