Supersymmetric regulators and supercurrent anomalies

The supercurrent anomalies of the supercurrent $\text{S}$_μ of the supersymmetric Yang-Mills theory in Wess-Zumino gauge are computed using the supersymmetric dimensional regulator of Siegel. It is shown that $\text{γ}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{=0}$ and $\text{?}{}_{\mathrm{\mu }}\text{S}{}^{\mathrm{\mu }}\text{≠0}$ in agreement with an earlier calculation based on the Adler-Rosenberg method. The problem of exhibiting the chiral anomaly and a regulator for local supersymmetry suggests that the interpretation of dimensional reduction in component language is incomplete.     

Nonlinear distribution function for a plasma obeying Vlasov-Maxwell system of equations

The nonlinear distribution function of Allis, generalised to include the transverse electromagnetic waves in a plasma, is used to set up the coupled wave equations for the longitudinal and the transverse modes. These are solved, keeping terms up to the cubic order of nonlinearity, by using the method of multiple scales. The equations of wave modulation are derived, which are solved to discuss the nature of the modulational instability and solitary wave propagation. It is found that the solutions so obtained satisfy conditions which are very similar to the well known Lighthill criterion for stability, appropriately modified due to the coupling of the two modes. The role of the average constant current due to any flow of the resonant and trapped electrons in determining the stability, is also discussed.     

Magnetic properties of amorphous ferromagnet Fe78Mo2B20

Low-field magnetic susceptibility and the magnetic field dependence of magnetization of Metglas 2605 A (Fe₇₈Mo₂B₂₀) were studied between 300 and 600 K and in fields up to 10kG. It is shown here that for an amorphous ferromagnetic alloy, the various methods of determination of Curie temperature T_c give the same value, which in this case is (564 ± 1) K. The critical exponent γ is 1.7 ± 0.1. Our low-field susceptibility measurements on Metglas 2605 (Fe₈₀B₂₀) gives a T_c of (634 ± 3) K while the reported high-field method value is 647 K. These results are discussed in terms of crystallization temperatures.     

Characterization of grafting density and binding efficiency of DNA and proteins on gold surfaces

The surface grafting density of biomolecules is an important factor for quantitative assays using a wide range of biological sensors. We use a fluorescent measurement technique to characterize the immobilization density of thiolated probe DNA on gold and hybridization efficiency of target DNA as a function of oligonucleotide length and salt concentration. The results indicate the dominance of osmotic and hydration forces in different regimes of salt concentration, which was used to validate previous simulations and to optimize the performance of surface-stress based microcantilever biosensors. The difference in hybridization density between complementary and mismatched target sequences was also measured to understand the response of these sensors in base-pair mismatch detection experiments. Finally, two different techniques for immobilizing proteins on gold were considered and the surface densities obtained in both cases were compared.     

Sub- and above-barrier fusion of loosely bound 6Li with 28Si

Fusion excitation functions are measured for the system ⁶Li + ²⁸Si using the characteristic $ \gamma$ -ray method, encompassing both the sub-barrier and above-barrier regions, viz, E _lab = 7-24 MeV. Two separate experiments were performed, one for the above-barrier region ( E _lab = 11-24 MeV) and another for the below-barrier region ( E _lab = 7-10 MeV). The results were compared with our previously measured fusion cross-section for the ⁷Li + ²⁸Si system. We observed the enhancement of the fusion cross-section at sub-barrier regions for both ⁶Li and ⁷Li , but the yield was substantially larger for ⁶Li . However, for well-above-barrier regions, a similar type of suppression was identified for both the systems.