2,739 research outputs found
Lorentz Violating Inflation
We explore the impact of Lorentz violation on the inflationary scenario. More
precisely, we study the inflationary scenario in the scalar-vector-tensor
theory where the vector is constrained to be unit and time like. It turns out
that the Lorentz violating vector affects the dynamics of the chaotic
inflationary model and divides the inflationary stage into two parts; the
Lorentz violating stage and the standard slow roll stage. We show that the
universe is expanding as an exact de Sitter spacetime in the Lorentz violating
stage although the inflaton field is rolling down the potential. Much more
interestingly, we find exact Lorentz violating inflationary solutions in the
absence of the inflaton potential. In this case, the inflation is completely
associated with the Lorentz violation. We also mention some consequences of
Lorentz violating inflation which can be tested by observations.Comment: 7 pages, 1 figur
Macdonald operators and homological invariants of the colored Hopf link
Using a power sum (boson) realization for the Macdonald operators, we
investigate the Gukov, Iqbal, Kozcaz and Vafa (GIKV) proposal for the
homological invariants of the colored Hopf link, which include
Khovanov-Rozansky homology as a special case. We prove the polynomiality of the
invariants obtained by GIKV's proposal for arbitrary representations. We derive
a closed formula of the invariants of the colored Hopf link for antisymmetric
representations. We argue that a little amendment of GIKV's proposal is
required to make all the coefficients of the polynomial non-negative integers.Comment: 31 pages. Published version with an additional appendi
Mineral Acquisition and Utilization Strategy of Three Tropical Forages at Different Phosphorus and Nitrogen Supply
A glasshouse experiment was conducted to examine mineral acquisition and utilization strategies of Brachiaria decumbens (BD), Brachiaria brizantha (BB) and Panicum maximum (PM). The plants were grown under nine treatments resulted from the combination of three levels of phosphorus (0, 25 and 50 kgP/ha) and three levels of nitrogen (25, 150 and 300 kgN/ha). BD showed the lowest value of root weight and root length per pot, but the highest efficiency of P and N uptake (P and N uptake mg / unit root weight g). On the other hand, PM showed lower mineral uptake efficiency, but the highest mineral use efficiency (dry matter production g / absorbed P and N mg). Moreover, total P and N uptake in BB was the highest, and this seems to be achieved by the multiplicative effect of moderate mineral uptake efficiency and the moderate size of the root system
Effects of Fertilization and Legume Introduction on the Forage Production of \u3ci\u3eBrachiaria decumbens\u3c/i\u3e Pastures
A grazing experiment was conducted to examine the effects of P and K fertilization and legume introduction on the forage production of Brachiaria decumbens (BD) pastures. Amount of biomass, dry matter production and forage quality were evaluated on BD pastures where three treatments were applied: without maintenance fertilizer (BD-N), with maintenance fertilizer (BD-F), and BD and Stylosanthes guianensis cv. Mineirao (SG) mixture with maintenance fertilizer (BD-FL). The fertilizer application increased an annual average of biomass and the contents of P and K in the leaves. On the other hand, the legume introduction had a positive influence on crude protein and digestibility, and the effect was obvious in the rainy season. The introduction of legume also increased litter decomposition constants, although the difference in the constants among the treatments was not significant
Issues on Generating Primordial Anisotropies at the End of Inflation
We revisit the idea of generating primordial anisotropies at the end of
inflation in models of inflation with gauge fields. To be specific we consider
the charged hybrid inflation model where the waterfall field is charged under a
U(1) gauge field so the surface of end of inflation is controlled both by
inflaton and the gauge fields. Using delta N formalism properly we find that
the anisotropies generated at the end of inflation from the gauge field
fluctuations are exponentially suppressed on cosmological scales. This is
because the gauge field evolves exponentially during inflation while in order
to generate appreciable anisotropies at the end of inflation the spectator
gauge field has to be frozen and scale invariant. We argue that this is a
generic feature, that is, one can not generate observable anisotropies at the
end of inflation within an FRW background.Comment: V3: new references added, JCAP published versio
A Note on Gauss-Bonnet Holographic Superconductors
We present an analytic treatment near the phase transition for the critical
temperature of (3+1)-dimensional holographic superconductors in
Einstein-Gauss-Bonnet gravity with backreaction. We find that the backreaction
makes the critical temperature of the superconductor decrease and condensation
harder. This is consistent with previous numerical results.Comment: 6 pages, typos corrected, references added, published versio
Symmetries and Observables for BF-theories in Superspace
The supersymmetric version of a topological quantum field theory describing
flat connections, the super BF-theory, is studied in the superspace formalism.
A set of observables related to topological invariants is derived from the
curvature of the superspace. Analogously to the non-supersymmetric versions,
the theory exhibits a vector-like supersymmetry. The role of the vector
supersymmetry and an additional new symmetry of the action in the construction
of observables is explained.Comment: 11 pages, LaTe
Pressure Dependence of Fragile-to-Strong Transition and a Possible Second Critical Point in Supercooled Confined Water
By confining water in nano-pores of silica glass, we can bypass the
crystallization and study the pressure effect on the dynamical behavior in
deeply supercooled state using neutron scattering. We observe a clear evidence
of a cusp-like fragile-to-strong (F-S) dynamic transition. Here we show that
the transition temperature decreases steadily with an increasing pressure,
until it intersects the homogenous nucleation temperature line of bulk water at
a pressure of 1600 bar. Above this pressure, it is no longer possible to
discern the characteristic feature of the F-S transition. Identification of
this end point with the possible second critical point is discussed.Comment: 4 pages, 3 figure
Forage Productivity of \u3ci\u3ePanicum maximum\u3c/i\u3e Pastures in Two Different Agropastoral Systems
Forage productivity was evaluated for Panicum maximum pastures established after 4 years of soybean cultivation in the summer (PM-SO), and 4 years of rotation of soybeans in the summer and millet for winter grazing (PM-MI). In the PM-MI pasture, biomass and dry matter production were much lower than in the PM-SO, and the amount of copper and nitrogen in the top part of the plants in PM-MI were significantly lower than that in PM-SO. Thus, it was considered that the shortage of copper and nitrogen restricted photosynthesis and forage production in PM-MI
Noncommutative models in patch cosmology
We consider several classes of noncommutative inflationary models within an
extended version of patch cosmological braneworlds, starting from a maximally
invariant generalization of the action for scalar and tensor perturbations to a
noncommutative brane embedded in a commutative bulk. Slow-roll expressions and
consistency relations for the cosmological observables are provided, both in
the UV and IR region of the spectrum; the inflaton field is assumed to be
either an ordinary scalar field or a Born-Infeld tachyon. The effects of
noncommutativity are then analyzed in a number of ways and energy regimes.Comment: 13 pages, 8 figures. Figures 1 and 2 are included in the text, Figs.
3-8 are in a low-resolution jpeg format. These and other high-resolution
figures are available upon request to the author ([email protected]). v3:
corrected misprint
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