Bootstrap equations for N = 4 SYM with defects

This paper focuses on the analysis of 4dN = 4 superconformal theories in the presence of a defect from the point of view of the conformal bootstrap. We will concentrate first on the case of codimension one, where the defect is a boundary that preserves half of the supersymmetry. After studying the constraints imposed by supersymmetry, we will obtain the Ward identities associated to two-point functions of 12 -BPS operators and write their solution as a superconformal block expansion. Due to a surprising connection between spacetime and R-symmetry conformal blocks, our results not only apply to 4dN = 4 superconformal theories with a boundary, but also to three more systems that have the same symmetry algebra: 4dN = 4 superconformal theories with a line defect, 3dN = 4 superconformal theories with no defect, and OSP(4∗|4) superconformal quantum mechanics. The superconformal algebra implies that all these systems possess a closed subsector of operators in which the bootstrap equations become polynomial constraints on the CFT data. We derive these truncated equations and initiate the study of their solutions

Bootstrapping the half-BPS line defect

We use modern bootstrap techniques to study half-BPS line defects in 4dN= 4 superconformal theories. Specifically, we consider the 1d CFT with OSP(4∗|4) superconformal symmetry living on such a defect. Our analysis is general and based only on symmetries, it includes however important examples like Wilson and ’t Hooft lines in N= 4 super Yang-Mills. We present several numerical bounds on OPE coefficients and conformal dimensions. Of particular interest is a numerical island obtained from a mixed correlator bootstrap that seems to imply a unique solution to crossing. The island is obtained if some assumptions about the spectrum are made, and is consistent with Wilson lines in planar N= 4 super Yang-Mills at strong coupling. We further analyze the vicinity of the strong-coupling point by calculating perturbative corrections using analytic methods. This perturbative solution has the sparsest spectrum and is expected to saturate the numerical bounds, explaining some of the features of our numerical results

On Correlation Functions of BPS Operators in 3d N= 6 Superconformal Theories

We introduce a novel harmonic superspace for 3dN=6 superconformal field theories that is tailor made for the study of correlation functions of BPS operators. We calculate a host of two- and three-point functions in full generality and put strong constraints on the form of four-point functions of some selected BPS multiplets. For the four-point function of 12-BPS operators we obtain the associated Ward identities by imposing the absence of harmonic singularities. The latter imply the existence of a solvable subsector in which the correlator becomes topological. This mechanism can be explained by cohomological reduction with respect to a special nilpotent supercharge

Bootstrapping N= 3 superconformal theories

We initiate the bootstrap program for N= 3 superconformal field theories (SCFTs) in four dimensions. The problem is considered from two fronts: the protected subsector described by a 2d chiral algebra, and crossing symmetry for half-BPS operators whose superconformal primaries parametrize the Coulomb branch of N= 3 theories. With the goal of describing a protected subsector of a family of N= 3 SCFTs, we propose a new 2d chiral algebra with super Virasoro symmetry that depends on an arbitrary parameter, identified with the central charge of the theory. Turning to the crossing equations, we work out the superconformal block expansion and apply standard numerical bootstrap techniques in order to constrain the CFT data. We obtain bounds valid for any theory but also, thanks to input from the chiral algebra results, we are able to exclude solutions with N= 4 supersymmetry,allowingustozoominonaspecific N= 3 SCFT

Development of an adventitious shoot regeneration system in cherries

Shoot regeneration in vitro is a difficult problem for cherry species. This study addressed three approaches to the problem, regeneration of adventitious shoots from roots and leaves of mature cherry clones, and from cotyledons of open-pollinated 'Royal Ann' cotyledons. Regeneration on roots occurred at a very low frequency. Adventitious shoots regenerated from only 17.5% of the cotyledons of open pollinated 'Royal Ann' cherries on Murashige and Skoog (MS) medium (Murashige et al., 1962) supplemented with 10 or 20 μM thidiazuron (TDZ) and 0 to 10 μM indolebutyric acid (IBA). Therefore, a two-stage process was developed for regeneration from leaves that resulted in high rates of adventitious shoot regeneration in some genotypes. Initially, leaves of several clones previously established in tissue culture were tested for shoot regeneration. The inter-specific Prunus hybrids Giessen 154-4 and Giessen 154-7, two of 15 clones tested, regenerated a small number of shoots when placed on MS medium and a combination of TDZ (5 to 10 μM) and naphthaleneacetic acid (NAA) or IBA (0.5 to 2.5 μM). Using these two clones, a two-stage process was developed to initiate and then promote elongation of adventitious shoots. In the first stage, increasing the agar concentration from 8 to 12 g/l and optimizing the TDZ and NAA concentrations to 10 μM and 1.25 μM respectively, markedly improved shoot initiation. After 20 days the cultures were transferred to a medium containing 5 μM BAP and 0.5 μM NAA. This second stage retarded callus growth and allowed meristems to elongate and form visible shoots. Applying this procedure to seven of the original 15 clones and one additional clone resulted in seven of the eight clones regenerating adventitious shoots, with four clones, 154-4, 154-7, 173-1 and 195-2, regenerating shoots on 50- 100% of the leaves. Changing the basal medium from Murashige and Skoog to Driver Kuniyuki walnut (DKW) medium (McGranahan et al., 1987) further increased the number of regenerating sites per leaf and meristem per leaf

Cryogenic Moisture Uptake in Foam Insulation for Space Launch Vehicles

Rigid polyurethane foams and rigid polyisocyanurate foams (spray-on foam insulation), like those flown on Shuttle, Delta IV, and will be flown on Ares-I and Ares-V, can gain an extraordinary amount of water when under cryogenic conditions for several hours. These foams, when exposed for eight hours to launch pad environments on one side and cryogenic temperature on the other, increase their weight from 35 to 80 percent depending on the duration of weathering or aging. This effect translates into several thousand pounds of additional weight for space vehicles at lift-off. A new cryogenic moisture uptake apparatus was designed to determine the amount of water/ice taken into the specimen under actual-use propellant loading conditions. This experimental study included the measurement of the amount of moisture uptake within different foam materials. Results of testing using both aged specimens and weathered specimens are presented. To better understand cryogenic foam insulation performance, cryogenic moisture testing is shown to be essential. The implications for future launch vehicle thermal protection system design and flight performance are discussed

A Portable Electronic Nose for Toxic Vapor Detection, Identification, and Quantification

The Space Program and military use large quantities of hydrazine and monomethyl hydrazine as rocket propellant, which are very toxic and suspected human carcinogens. Current off-the-shelf portable instruments require 10 to 20 minutes of exposure to detect these compounds at the minimum required concentrations and are prone to false positives, making them unacceptable for many operations. In addition, post-mission analyses of grab bag air samples from the Shuttle have confirmed the occasional presence of on-board volatile organic contaminants, which also need to be monitored to ensure crew safety. A new prototype instrument based on electronic nose (e-nose) technology has demonstrated the ability to qualify (identify) and quantify many of these vapors at their minimum required concentrations, and may easily be adapted to detect many other toxic vapors. To do this, it was necessary to develop algorithms to classify unknown vapors, recognize when a vapor is not any of the vapors of interest, and estimate the concentrations of the contaminants. This paper describes the design of the portable e-nose instrument, test equipment setup, test protocols, pattern recognition algorithms, concentration estimation methods, and laboratory test results

Total Hydrocarbon Content (THC) Testing in Liquid Oxygen (LOX)

The measured Total Hydrocarbon Content (THC) levels in liquid oxygen (LOX) systems at Stennis Space Center (SSC) have shown wide variations. Examples of these variations include the following: 1) differences between vendor-supplied THC values and those obtained using standard SSC analysis procedures; and 2) increasing THC values over time at an active SSC test stand in both storage and run vessels. A detailed analysis of LOX sampling techniques, analytical instrumentation, and sampling procedures will be presented. Additional data obtained on LOX system operations and LOX delivery trailer THC values during the past 12-24 months will also be discussed. Field test results showing THC levels and the distribution of the THC's in the test stand run tank, modified for THC analysis via dip tubes, will be presented