NN-point amplitudes for d=2 c=1 Discrete States from String Field Theory

Starting from string field theory for 2d gravity coupled to c=1 matter we analyze N-point off-shell tree amplitudes of discrete states. The amplitudes exhibit the pole structure and we use the oscillator representation to extract the residues. The residues are generated by a simple effective action. We show that the effective action can be directly deduced from a string field action in a special transversal-like gauge.Comment: 12 pages, latex, 1 figur

Noncommutative Field Theories and (Super)String Field Theories

In this lecture notes we explain and discuss some ideas concerning noncommutative geometry in general, as well as noncommutative field theories and string field theories. We consider noncommutative quantum field theories emphasizing an issue of their renormalizability and the UV/IR mixing. Sen's conjectures on open string tachyon condensation and their application to the D-brane physics have led to wide investigations of the covariant string field theory proposed by Witten about 15 years ago. We review main ingredients of cubic (super)string field theories using various formulations: functional, operator, conformal and the half string formalisms. The main technical tools that are used to study conjectured D-brane decay into closed string vacuum through the tachyon condensation are presented. We describe also methods which are used to study the cubic open string field theory around the tachyon vacuum: construction of the sliver state, ``comma'' and matrix representations of vertices.Comment: 160 pages, LaTeX, 29 EPS figures. Lectures given by I.Ya.Aref'eva at the Swieca Summer School, Brazil, January 2001; Summer School in Modern Mathematical Physics, Sokobanja, Yugoslavia, August 2001; Max Born Symposium, Karpacz, Poland, September, 2001; Workshop "Noncommutative Geometry, Strings and Renormalization", Leipzig, Germany, September 2001. Typos corrected, references adde

Chaos-Order Transition in Matrix Theory

Classical dynamics in SU(2) Matrix theory is investigated. A classical chaos-order transition is found. For the angular momentum small enough (even for small coupling constant) the system exhibits a chaotic behavior, for angular momentum large enough the system is regular.Comment: 14 pages, Latex, 10 figure

GEOCHEMISTRY AND ORIGIN OF THE EASTERN SAYAN OPHIOLITES, TUVA-MONGOLIAN MICROCONTINENT (SOUTHERN SIBERIA)

The Eastern Sayan ophiolites (1020 Ma) of the Tuva-Mongolian microcontinent are believed to be the most ancient ophiolite of the Central Asian Orogenic Belt [Khain et al., 2002].The Eastern Sayan ophiolites (1020 Ma) of the Tuva-Mongolian microcontinent are believed to be the most ancient ophiolite of the Central Asian Orogenic Belt [Khain et al., 2002]

Tailoring Ni and Sr2Mg0.25Ni0.75MoO6 −δ cermet compositions for designing the fuel electrodes of solid oxide electrochemical cells

The design of new electrode materials for solid oxide electrochemical cells, which are stable against redox processes as well as exhibiting carbon/sulphur tolerance and high electronic conductivity, is a matter of considerable current interest as a means of overcoming the disadvantages of traditional Ni-containing cermets. In the present work, composite materials having the general formula (1−x)Sr2Mg0.25Ni0.75MoO6−δ + xNiO (where x = 0, 15, 30, 50, 70 and 85 mol.%) were successfully prepared to be utilised in solid oxide fuel cells. A detailed investigation of the thermal, electrical, and microstructural properties of these composites, along with their phase stability in oxidising and reducing atmospheres, was carried out. While possessing low thermal expansion coefficient (TEC) values, the composites having low Ni content (15 mol.%-70 mol.%) did not satisfy the requirement of high electronic conductivity. Conversely, the 15Sr2Mg0.25Ni0.75MoO6−δ + 85NiO samples demonstrated very high electrical conductivity (489 S sm−1 at 850 ◦C in wet H2) due to well-developed Ni-based networks, and no deterioration of thermal properties (TEC values of 15.4 × 10−6 K−1 in air and 14.5 × 10−6 K−1 in 50%H2/Ar; linear expansion behaviour in both atmospheres). Therefore, this material has potential for use as a component of a fuel cell electrode system. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Russian Foundation for Basic Research, RFBR: 18-33-00544Comparison of the XRD data of the 50Sr2Mg0.25Ni0.75MoO6–δ + 50NiO and 50Sr2Mg0.25Ni0.75MoO6–δ + 50Ni 2 0.25 0.75 6−δ 50cNomiOpoasnidtes5,0FSirg2uMrge0.25S2:NCi0.75omMpaorOiso6−nδo+ft5h0eNrie,lFaitgivueredSim3:eInmsiaogneschoafnthgeessuorff5a0cSerm2Mogrp0.2h5Nolio0g.75yMfooOrt6h–δe+as5-0sNinitOereadnd 50Sr2M2g0.250N.25i0.75M0.7o5O6–δ +6−δ50Ni, Figure S3: Images of the surface◦morphology for the as-sintered (1– x)Sr2Mg0.25Ni0.75MoO6–δ + xNiO ceramic materials at high magnification, Table S1: Total conductivity of AMutgh-obraCseodnmtrioblyubtidoantse:mCaotnecreiapltsuwaliitzhataiodno,uLb.Sle.Sp.earnodvAsk.Aite.Vs.t;rmucettuhroedaotlo8g0y0,°DC.Ain.Mre.;dvuacliindgataiotmn,oDsp.Kh.eKr.easn. d V.Y.S.; formal analysis, D.A.M.; investigation, L.S.S.; resources, D.K.K. and V.Y.S.; writing—original draft preparation, ?uthorContributions:Conceptualization,L.S.and?.V.;methodology,D.M.;validation,D.K.andV.S.;formal adanmailnyissitsr,aDtio.Mn,.;Li.nSv.Se.s;tfiugnatdioinng,Lac.Sq.u.;irseitsioounr,cLe.sS,.SD..K.andV.S.;writing—originaldraftpreparation,L.S.andD.M.; writing—reviewandediting,D.M.;visualization,L.S.;supervision,?.V.;projectadministration,L.S;funding Funding: This work is supported by the Russian Foundation for Basic Research (project no. 18-33-00544). acquisition, L.S

Descent Relations and Oscillator Level Truncation Method

We reexamine the oscillator level truncation method in the bosonic String Field Theory (SFT) by calculation the descent relation =Z_3<V_2|. For the ghost sector we use the fermionic vertices in the standard oscillator basis. We propose two new schemes for calculations. In the first one we assume that the insertion satisfies the overlap equation for the vertices and in the second one we use the direct calculations. In both schemes we get the correct structures of the exponent and pre-exponent of the vertex <V_2|, but we find out different normalization factors Z_3.Comment: 21 pages, 10 figures, Late

Dynamics in nonlocal linear models in the Friedmann-Robertson-Walker metric

A general class of cosmological models driven by a nonlocal scalar field inspired by the string field theory is studied. Using the fact that the considering linear nonlocal model is equivalent to an infinite number of local models we have found an exact special solution of the nonlocal Friedmann equations. This solution describes a monotonically increasing Universe with the phantom dark energy.Comment: 18 pages, 3 figures, a few misprints in Section 5 have been correcte