Star-product functions in higher-spin theory and locality

Properties of the functional classes of star-product elements associated with higher-pin gauge fields and gauge parameters are elaborated. Cohomological interpretation of the nonlinear higher-spin equations is given. An algebra \( \mathrm{\mathscr{H}} \), where solutions of the nonlinear higher-spin equations are valued, is found. A conjecture on the classes of star-product functions underlying (non)local maps and gauge transformations in the nonlinear higher-spin theory is proposed.

Identification of Bulk coupling constant in Higher Spin/ABJ correspondence

We study the conjectured duality between the $\mathcal{N}=6$ Vasiliev higherspin theory on $AdS_4$ and 3d $\mathcal{N}=6$ superconformal Chern-Simonsmatter theory known as the ABJ theory. We discuss how the parameters in the ABJtheory should be related to the bulk coupling constant in the Vasiliev theory.For this purpose, we compute two-point function of stress tensor in the ABJtheory by using supersymmmetry localization. Our result justifies the proposalby arXiv:1504.00365 and determine the unknown coefficient in the previous work.

Group manifold approach to higher spin theory

We consider the group manifold approach to higher spin theory. The deformedlocal higher spin transformation is realized as the diffeomorphismtransformation in the group manifold $\textbf{M}$. With the suitable rheonomycondition and the torsion constraint imposed, the unfolded equation can beobtained from the Bianchi identity, by solving which, fields in $\textbf{M}$are determined by the multiplet at one point, or equivalently, by$(W^{[a(s-1),b(0)]}_{\mu},H)$ in $AdS_{4}\subset \textbf{M}$. Although thespace is extended to $\textbf{M}$ to get the geometrical formulation, thedynamical degrees of freedom are still in $AdS_{4}$. The $4d$ equations ofmotion for $(W^{[a(s-1),b(0)]}_{\mu},H)$ are obtained by plugging the rheonomycondition into the Bianchi identity. The proper rheonomy condition allowing forthe maximum on-shell degrees of freedom is given by Vasiliev equation. We alsodiscuss the theory with the global higher spin symmetry, which is in parallelwith the WZ model in supersymmetry.

Higher Spins and Matter Interacting in Dimension Three

The spectrum of Prokushkin--Vasiliev Theory is puzzling in light of theGaberdiel--Gopakumar conjecture because it generically contains an additionalsector besides higher-spin gauge and scalar fields. We find the uniquetruncation of the theory avoiding this problem to order 2 in perturbationsaround AdS$_3$. The second-order backreaction on the physical gauge sectorinduced by the scalars is computed explicitly. The cubic action for thephysical fields is determined completely. We comment on a different higher-spintheory without such additional fields at $\lambda=1$.

Estimation of intraband and interband relative coupling constants from temperature dependences of the order parameter for two-gap superconductors

We present temperature dependences of the large and the small superconductinggaps measured directly by SnS-Andreev spectroscopy in various Fe-basedsuperconductors and MgB$_2$. The experimental $\Delta_{L,S}(T)$ are well-fittedwith a two-gap model based on Moskalenko and Suhl system of equations(supplemented with a BCS-integral renormalization). From the the fittingprocedure, we estimate the key attribute of superconducting state \textemdashrelative electron-boson coupling constants and eigen BCS-ratios for bothcondensates. Our results evidence for a driving role of a strong intrabandcoupling in the bands with the large gap, whereas interband coupling is ratherweak for all the superconductors under study.

Criticality Safety Evaluation of a Swiss wet storage pool using a global uncertainty analysis methodology

Drastic changes in the distribution of branched tetraether lipids in suspended matter and sediments from the Yenisei River and Kara Sea (Siberia): Implications for the use of brGDGT-based proxies in coastal marine sediments

The distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils has been shown to correlate with pH and mean annual air temperature. Because of this dependence brGDGTs have found an application as palaeoclimate proxies in coastal marine sediments, based on the assumption that their distribution is not altered during the transport from soils to marine systems by rivers. To study the processes acting on the brGDGT distributions, we analysed the full suite of brGDGTs, including the recently described 6-Me brGDGTs, in both the suspended particulate matter (SPM) of the Siberian Yenisei River and the SPM and sediments of its outflow in the Kara Sea. The brGDGT distribution in the SPM of the Yenisei River was fairly constant and characterized by high abundances of the 6-Me brGDGTs, reflecting their production at the neutral pH of the river water. However, the brGDGT distribution showed marked shifts in the marine system. Firstly, in the Yenisei River Mouth, the fractional abundance of the 6-Me brGDGTs decreases sharply. The brGDGT signature in the Yenisei River Mouth possibly reflects brGDGTs delivered during the spring floods that may carry a different distribution. Also, coastal cliffs were shown to contain brGDGTs and to influence especially those sites without major river inputs (e.g. Khalmyer Bay). Further removed from the river mouth, in-situ production of brGDGTs in the marine system influences the distribution. However, also the fractional abundance of the tetramethylated brGDGT Ia increases, resulting in a distribution that is distinct from in-situ produced signals at similar latitudes (Svalbard). We suggest that this shift may be caused by preferential degradation of labile (riverine in-situ produced) brGDGTs and the subsequent enrichment in less labile (soil) material. The offshore distribution indeed agrees with the brGDGT distribution encountered in a lowland peat. This implies that the offshore Kara Sea sediments possibly carry a soil-dominated signal, indicating potential for palaeoclimate reconstructions at this site. Both in the river system and coastal cliffs, brGDGTs were much more abundant than crenarchaeol, an archaeal isoprenoid GDGT, resulting in high (>0.93) Branched and Isoprenoid Tetraether (BIT) index values. Moving downstream in the marine sediments, a decrease in brGDGT concentrations, coeval with an increase in crenarchaeol, resulted in decreasing BIT index values. This decrease correlates with changes in bulk proxies for terrigenous input (δ13Corg, C/N), confirming the use of the BIT index to trace the delivery of river-transported and coastal cliff-derived terrigenous organic matter.

80th birthday of Professor Mikhail Dimitrov Mikhailov

Approximation algorithms for clique transversals on some graph classes

Given a graph G = ( V , E ) a clique is a maximal subset of pairwise adjacent vertices of V of size at least 2. A clique transversal is a subset of vertices that intersects the vertex set of each clique of G. Finding a minimum-cardinality clique transversal is NP-hard for the following classes: planar, line and bounded degree graphs. For line graphs we present a 3-approximation for the unweighted case and a 4-approximation for the weighted case with nonnegative weights; a ¿ ( Δ ( G ) + 1 ) / 2 ¿ -approximation for bounded degree graphs and a 3-approximation for planar graphs. A 3-approximation algorithm for unweighted line graphs.A 4-approximation algorithm for weighted line graphs.A 3-approximation algorithm for planar graphs.A ¿ ( Δ ( G ) + 1 ) / 2 ¿ -approximation algorithm for bounded degree graphs.

Uniaxial anisotropy and low-temperature antiferromagnetism of Mn2BO4 single crystal

The Mn2BO4 single crystals have been grown using the flux technique. Thecareful study crystal structure and magnetic properties have been carried out.The antiferromagnet transition at TN = 26 K has been traced through the dcmagnetization and specific heat temperature dependences. The magnetic uniaxialanisotropy has been detected with easy axis of magnetization lying in ab-plane.A reduction of the effective magnetic moment value is assigned to thenon-quenched orbital moment of Jahn-Teller Mn3+ ions. Based on thesuperexchange interactions calculations the magnetic behavior is discussed.