Magnon dispersion to four loops in the ABJM and ABJ models

The ABJM model is a superconformal Chern-Simons theory with N=6 supersymmetry which is believed to be integrable in the planar limit. However, there is a coupling dependent function that appears in the magnon dispersion relation and the asymptotic Bethe ansatz that is only known to leading order at strong and weak coupling. We compute this function to four loops in perturbation theory by an explicit Feynman diagram calculation for both the ABJM model and the ABJ extension. We find that all coefficients have maximal transcendentality. We then compute the four-loop wrapping correction for a scalar operator in the 20 of SU(4) and find that it agrees with a recent prediction from the ABJM Y-system of Gromov, Kazakov and Vieira. We also propose a limit of the ABJ model that might be perturbatively integrable at all loop orders but has a short range Hamiltonian.Comment: LaTeX, feynmp, 17 pages; v2: coupling factor in one Feynman diagram corrected: modified result in the ABJ case only, formulations improved, typos fixed, references added; v3: signs of three diagrams corrected, modifying the final resul

Process Characterization for Integration of Esaki Diodes into Aspect Ratio Trapping Material

A process for forming Esaki Diodes in Germanium bulk material was characterized. In doing so its processing characteristics were studied to determine whether it could be transferred into Aspect Ratio Trapping, ART, material. It was determined that transfer was feasible with the optimization of the spin on dopant process and strict control of the wet etching of the spin on dopant and Aluminum. Following process characterization electrical data was collected for a range of devices with varying process parameters. The maximum peak to valley current ratio was 1.5 and maximum peak current density was 5kA/cm2. The PVCR value was very close to data collected by a group at Notre Dame who’s process was the basis for the one used in this project4. However, the maximum peak current density was much lower, most likely due the decreased dopant concentration of the spin on dopant. Upon completion of the project a process, which could be transferred to ART, was obtained and baseline data was collected for comparison to future devices

Superspace calculation of the four-loop spectrum in N=6 supersymmetric Chern-Simons theories

Using N=2 superspace techniques we compute the four-loop spectrum of single trace operators in the SU(2) x SU(2) sector of ABJM and ABJ supersymmetric Chern-Simons theories. Our computation yields a four-loop contribution to the function h^2(\lambda) (and its ABJ generalization) in the magnon dispersion relation which has fixed maximum transcendentality and coincides with the findings in components given in the revised versions of arXiv:0908.2463 and arXiv:0912.3460. We also discuss possible scenarios for an all-loop function h^2(\lambda) that interpolates between weak and strong couplings.Comment: LaTeX, feynmp, 34 pages; v2: typos corrected, formulations improved, references adde

Optical dispersion relations for diamondlike carbon films

Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E = 1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction, N, were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap, Eg, obtained in this way was compared the the Eg value using conventional Tauc plots and reasonably good agreement was obtained

Notes on Certain Elastic Peculiarities of Phosphor Bronze Wires

Some previous work by one of the authors with wires of an alloy of platinum-iridium, portions of which work were published in these Proceedings, indicated that when the wires were used as suspensions for torsion pendulums, the relations between the period of vibration and the amplitude were exceedingly complicated. The effect of drawing these wires was dealt with in another paper. In all these papers referred to, the statement was made that similar tests should be applied to some of the more common wires in the hope of finding similar, even though smaller effects. Through press of work these experiments have been deferred until the present year. This particular paper will deal with but one feature of the work, namely, the effect of drawing on the elastic nature of phosphor bronze wires. The writers are indebted to the American Electrical Works, of Phillipsdale, Rhode Island, for kindly furnishing them with specimens of the wires

Desorption Dynamics of Heavy Alkali Metal Atoms (Rb, Cs) off the Surface of Helium Nanodroplets

We present a combined ion imaging and density functional theory study of the dynamics of the desorption process of rubidium and cesium atoms off the surface of helium nanodroplets upon excitation of the perturbed $6s$ and $7s$ states, respectively. Both experimental and theoretical results are well represented by the pseudodiatomic model for effective masses of the helium droplet in the desorption reaction of m_eff/m_He~10 (Rb) and 13 (Cs). Deviations from this model are found for Rb excited to the 6p state. Photoelectron spectra indicate that the dopant-droplet interaction induces relaxation into low-lying electronic states of the desorbed atoms in the course of the ejection process.Comment: in press, J. Phys. Chem. A (2014

Comparison of biochemical and histological methods for the evaluation of the in situ nutritional condition of marine fish larvae

To estimate the importance of starvation induced mortality for recruitment of marine fish larvae three distinct methods were applied to determine the nutritional condition of fish larvae in situ. In addition to highly sensitive fluorescence techniques for analysing RNA/DNA ratios and tryptic enzyme activities histological standard methods were used to compare the nutritional status of fish larvae of the genus Vinciguerria (Photichthyidae) caught in two ecologically different areas of the Indian Ocean: In the central Arabian Sea and on the continental shelf of Pakistan. A comparison of the results elaborated by the distinct methods shows a trend towards better nutritional conditions for fish larvae from the offshore region

The Absorption of Light Passing through Deep Slits as a Function of the Length and Depth of the Slits and of the Wave Length of the Light

As indicated by Rayleigh, practically every slit is a Deep slit, and a Thin slit can be obtained only with the greatest difficulty. Rayleigh used for the latter a fine scratch in a thin silver film deposited upon glass. In the present work experiments were made with a series of slits with steel jaws, varying in depth from that of the thin safety razor blades to approximately 2.5 cm. The intensity of the transmitted light was experimentally determined as a function of the width and depth of the slits, and of the wave length of the light. For narrow slits, the narrowness depending upon the depth and wave length, practically complete polarization, with the electric vector parallel to the length of the slit, was noted, but exact measurements were deferred to a later work. On the basis of diffraction, multiple reflections, and the alteration of the ratios of the two electric vectors due to the latter, a simple theory is developed, the results of which agree well with the experimental results. The chief fact derived from the experiments is that for narrow slits the total amount of light transmitted is not, even approximately, proportional to the opening, and that therefore the use of such slits for photometric purposes will lead, unless proper corrections are made, to erroneous values for the intensity of the transmitted light

A new technique for oil backstreaming contamination measurements

Due to the large size and the number of diffusion pumps, space simulation chambers cannot be easily calibrated by the usual test dome method for measuring backstreaming from oil diffusion pumps. In addition, location dependent contamination may be an important parameter of the test. The backstreaming contamination was measured in the Space Power Facility (SPF) near Sandusky, OH, the largest space simulation vacuum test chamber in the U.S.. Small clean silicon wafers placed at all desired measurement sites were used as contamination sensors. The facility used diffusion pumps with DC 705 oil. The thickness of the contamination oil film was measured using ellipsometry. Since the oil did not wet the silicon substrate uniformly, two analysis models were developed to measure the oil film: (1) continuous, homogeneous film; and (2) islands of oil with the islands varying in coverage fraction and height. In both cases, the contamination film refractive index was assumed to be that of DC 705. The second model improved the ellipsometric analysis quality parameter by up to two orders of magnitude, especially for the low coverage cases. Comparison of the two models shows that the continuous film model overestimates the oil volume by less than 50 percent. Absolute numbers for backstreaming are in good agreement with published results for diffusion pumps. Good agreement was also found between the ellipsometric results and measurements done by x-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM) on examples exposed to the same vacuum runs