Leptogenesis in inflationary models with non-Abelian gauge fields

A scenario of leptogenesis was introduced in Alexander et al. (Phys Rev Lett 96:081301, 2006) which works during inflationary period within standard model of particle physics setup. In this scenario lepton number is created by the gravitational chiral anomaly which has a non-zero expectation value for models of inflation driven by pseudoscalar field(s). Here, we observe that models of inflation involving non-Abelian gauge fields, e.g. the chromo-natural inflation (Adshead and Wyman in Phys Rev Lett 108:261302, 2012) or the gauge-flation (Maleknejad and Sheikh-Jabbari in Phys Lett B 723:224, 2013. arXiv:1102.1513 [hep-ph]), have a parity-violating tensor mode (graviton) spectrum and naturally lead to a non-vanishing expectation value for the gravitational chiral anomaly. Therefore, one has a natural leptogenesis scenario associated with these inflationary setups, inflato-natural leptogenesis. We argue that the observed value of baryon-to-photon number density can be explained in a natural range of parameters in these models.     

Investigation of the effective parameters on the synthesis of Ni-ferrite nanocrystalline powders by coprecipitation method

In this work, synthesis of nanostructured NiFe₂O₄ powders by coprecipitation method using novel precursors, followed by calcination was investigated for the first time. The synthesis was started by dissolving Fe and Ni chlorides and ammonium ferrous sulfate in deionized water. After stirring, the precipitating agent of NaOH was added to the solution and after 1 h aging, the resultant precipitates were washed with deionized water and acetone. Then the powder was characterized and the effects of different parameters such as molarity of precipitant, calcination temperature and the molar ratio of Ni²⁺ ion to the total iron ions were studied. It is concluded that an increase in molarity of precipitant can decrease the calcination temperature. The best conditions giving a single phase Ni-ferrite were using of 2.2 molar NaOH, calcination temperature of 900 °C and the molar ratio of nickel to iron as 0.5. The crystallite size of resulting ferrites was below 50 nm.     

Design and optimization of thin film polarizer at the wavelength of 1540 nm using differential evolution algorithm

In this paper, a thin film polarizer at the wavelength of 1540 nm in infrared region was designed and optimized using differential evolution method. It is shown how the algorithm’s parameters can change the output result to obtain the best consequence of optimization. This polarizer consists of a few pairs of high and low refractive index dielectric materials, titanium dioxide and silicon dioxide, respectively, with \(BK_{7}\) glass substrate and the angle of incident light was supposed 56° that is the Brewster angle for \(BK_{7}\) glass. Our final optimized polarizer has 91.20 and 0.336% transmittance for P and S polarization, respectively, and a 271 ratio of \(\frac{{T_{P} }}{{T_{S} }}\) which has high significance for this polarizer. It consists of eight pairs of layers with low and high refractive index materials and 3369.1 nm physical thickness which is used to separate S and P polarized light for Q-switching process.     

Introduction of a new dichlorophen electrochemical sensor relying on the modified glassy carbon electrode (GCE) with carboxyl-functionalized graphene oxide/poly (L-arginine)

Journal of Solid State Electrochemistry - Dichlorophen (Dcp), a harmful environmental pollutant, is broadly utilized in veterinary medications, chemical fertilizers, pesticides, cosmetics, and...