2,364 research outputs found

    Deformation theory of objects in homotopy and derived categories II: pro-representability of the deformation functor

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    This is the second paper in a series. In part I we developed deformation theory of objects in homotopy and derived categories of DG categories. Here we extend these (derived) deformation functors to an appropriate bicategory of artinian DG algebras and prove that these extended functors are pro-representable in a strong sense.Comment: Alexander Efimov is a new co-author of this paper. New material was added: A_{\infty}-structures, Maurer-Cartan theory for A_{\infty}-algebras. This allows us to strengthen our main results on the pro-representability of pseudo-functors coDEF_{-} and DEF_{-}. We also obtain an equivalence between homotopy and derived deformation functors under weaker hypothese

    Integrable magnetic geodesic flows on Lie groups

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    Right-invariant geodesic flows on manifolds of Lie groups associated with 2-cocycles of corresponding Lie algebras are discussed. Algebra of integrals of motion for magnetic geodesic flows is considered and necessary and sufficient condition of integrability in quadratures is formulated. Canonic forms for 2-cocycles of all 4-dimensional Lie algebras are given and integrable cases among them are separated.Comment: 16 page

    Survey of the world practice of implementing energy-efficient technologies in terms of mining enterprises

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    Purpose is the analysis of world practice of applying the best available techniques to increase energy saving and energy efficiency of mining enterprises being the important factor of the economic development. Methods. The research methodology is based on the scientific approaches: historical-evolutionary, interdisciplinary, integration, process, and situational. Methods of retrospective, categorical, and system analysis as well as modeling have been applied. The analysis was performed on the basis of both initial information sources (original texts of legislative documents, strategies) and material of the international analytical organizations (International Energy Agency, World Bank) as well as the data of official statistical records. Findings. For the first time, different variants of the best available techniques in Japan, the USA, and the EU have been analyzed as well as the role of a state in applying institutional measures of energy efficiency support, including mining complex, and prospects of its use in the Russian Federation. It has been determined that energy efficiency is the effective and economically feasible tool in reaching sustainable development of the national economy. It has been demonstrated that energy saving and increased energy efficiency may reduce the needs in investment, raise industrial competitiveness and consumer welfare as well as improve environmental protection owing to the reduced greenhouse gas emissions and decreased air pollution. Energy efficiency growth has direct effect upon the industrial competitiveness; it can be achieved by means of innovations. Originality. Emphasis has been put on the key scientific and technical aspects and approaches stimulating increased energy efficiency in the developed countries under the effect of strong, coordinated, and consistent national policy in different sectors of economy. Practical implications. The carried-out analysis is useful in terms of the innovative and technological development of different industries of the Russian Federation in the context of its complicated cooperation with European countries and the USA, dependence on foreign technologies, and limited access to them.Мета. Аналіз світового досвіду використання найкращих доступних технологій для підвищення енергозбереження та енергетичної ефективності гірничодобувних підприємств, які є важливими факторами інноваційного розвитку і економіки. Методика. В основі методології дослідження застосовані наукові підходи: історико-еволюційний, міждисциплінарний, інтеграційний, процесний і ситуаційний. Використано методики ретроспективного, категоріального, системного аналізу, моделювання. Аналіз виконувався на основі як первинних інформаційних джерел (оригінальні тексти законодавства, стратегій), так і на основі матеріалів міжнародних аналітичних організацій (Міжнародного енергетичного агентства, Світового банку), а також даних офіційного статистичного обліку. Результати. Вперше проаналізовані різні варіанти найкращих доступних технологій в Японії, США, ЄС, роль держави у застосуванні інституційних заходів підтримки енергоефективності, в тому числі у гірничодобувному комплексі, а також перспективи їх використання у Російській Федерації. Визначено, що енергоефективність є дієвим і рентабельним інструментом досягнення сталого розвитку економіки країни в цілому. Показано, що енергозбереження та підвищення енергоефективності може знижувати потребу в інвестиціях, збільшити конкурентоспроможність промисловості й добробут споживача, а також покращувати охорону навколишнього середовища, завдяки зниженню викидів парникових газів та зменшенню забруднення повітря. Підвищення енергоефективності безпосередньо впливає на конкурентоспроможність промисловості та може бути досягнуто за рахунок інновацій. Наукова новизна. Виділено ключові науково-технічні асп екти й підходи, що стимулюють підвищення енергоефективності в розвинених зарубіжних країнах під впливом сильної, скоординованої та послідовної політики держави у різних секторах економіки. Практична значимість. Проведений аналіз корисний у побудові інноваційного та технологічного розвитку різних галузей Російської Федерації в умовах її непростої взаємодії з країнами Європи і США, залежно від зарубіжних технологій та обмеженого доступу до них.Цель. Анализ мирового опыта использования наилучших доступных технологий для повышения энергосбережения и повышение энергетической эффективности горнодобывающих предприятий, которые являются важными факторами развития экономики. Методика. В основе методологии исследования применены научные подходы: историко-эволюционный, междисциплинарный, интеграционный, процессный и ситуационный. Использованы методики ретроспективного, категориального, системного анализа, моделирования. Анализ выполнялся на основе как первичных информационных источников (оригинальные тексты законодательства, стратегий), так и на основе материалов международных аналитических организаций (Международного энергетического агентства, Всемирного банка), а также данных официального статистического учета. Результаты. Впервые проанализированы различные варианты наилучших доступных технологий в Японии, США, ЕС, а также роль государства в применении институциональных мер поддержки энергоэффективности, в том числе в горнодобывающем комплексе, перспективы его использования в Российской Федерации. Определено, что энергоэффективность является действенным и рентабельным инструментом достижения устойчивого развития экономики страны в целом. Показано, что энергосбережение и повышение энергоэффективности может снижать потребность в инвестициях, увеличить конкурентоспособность промышленности и благосостояние потребителя, а также улучшать охрану окружающей среды, благодаря снижению выбросов парниковых газов и уменьшению загрязнения воздуха. Повышение энергоэффективности напрямую влияет на конкурентоспособность промышленности и может быть достигнуто за счет инноваций. Научная новизна. Выделены ключевые научно-технические аспекты и подходы, стимулирующие повышение энергоэффективности в развитых зарубежных странах под влиянием сильной, скоординированной и последовательной политики государства в различных секторах экономики. Практическая значимость. Проведенный анализ полезен в построении инновационного и технологического развития различных отраслей Российской Федерации в условиях ее непростого взаимодействия со странами Европы и США, зависимости от зарубежных технологий и ограниченного доступа к ним.This article was prepared as a part of the project section of the government contract as requested by the Ministry of Science and Higher Education of the Russian Federation on the subject formulated as “Development of Methodological Principles and Organizational Economic Mechanism of Strategic Management of Economic Security in Russia” (Assignment No. 26.3913.2017/4.6)

    Strong and radiative decays of the Ds0*(2317) meson in the DK-molecule picture

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    We consider a possible interpretation of the new charm-strange meson Ds0*(2317) as a hadronic molecule - a bound state of D and K mesons. Using an effective Lagrangian approach we calculate the strong Ds0* to Ds pi0 and radiative Ds0* to Ds* gamma decays. A new impact related to the DK molecular structure of the Ds0*(2317) meson is that the presence of u(d) quarks in the D and K mesons gives rise to a direct strong isospin-violating transition Ds0* to Ds pi0 in addition to the decay mechanism induced by eta-pi0 mixing considered previously. We show that the direct transition dominates over the eta-pi0 mixing transition in the Ds0* to Ds pi0 decay. Our results for the partial decay widths are consistent with previous calculations.Comment: 22 pages, 4 figures, accepted for publication in Phys. Rev.

    Deformation theory of objects in homotopy and derived categories III: abelian categories

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    This is the third paper in a series. In part I we developed a deformation theory of objects in homotopy and derived categories of DG categories. Here we show how this theory can be used to study deformations of objects in homotopy and derived categories of abelian categories. Then we consider examples from (noncommutative) algebraic geometry. In particular, we study noncommutative Grassmanians that are true noncommutative moduli spaces of structure sheaves of projective subspaces in projective spaces.Comment: Alexander Efimov is a new co-author of this paper. Besides some minor changes, a new part (part 3) about noncommutative Grassmanians was adde

    The structure of the atomic helium trimers: Halos and Efimov states

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    The Faddeev equations for the atomic helium-trimer systems are solved numerically with high accuracy both for the most sophisticated realistic potentials available and for simple phenomenological potentials. An efficient numerical procedure is described. The large-distance asymptotic behavior, crucial for weakly bound three-body systems, is described almost analytically for arbitrary potentials. The Efimov effect is especially considered. The geometric structures of the bound states are quantitatively investigated. The accuracy of the schematic models and previous computations is comparable, i.e. within 20% for the spatially extended states and within 40% for the smaller ^4He-trimer ground state.Comment: 32 pages containing 7 figures and 6 table

    Non-commutative low dimension spaces and superspaces associated with contracted quantum groups and supergroups

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    Quantum planes which correspond to all one parameter solutions of QYBE for the two-dimensional case of GL-groups are summarized and their geometrical interpretations are given. It is shown that the quantum dual plane is associated with an exotic solution of QYBE and the well-known quantum hh-plane may be regarded as the quantum analog of the flag (or fiber) plane. Contractions of the quantum supergroup GLq(12) GL_q(1|2) and corresponding quantum superspace Cq(12) C_q(1|2) are considered in Cartesian basis. The contracted quantum superspace Ch(12;ι) C_h(1|2;\iota) is interpreted as the non-commutative analog of the superspace with the fiber odd part.Comment: Talk given at the XIII Int. Coll. on Integrable Systems and Quantum Groups, June 17-19, 2004, Prague, Czech Republic. Submitted in Czech. J. of Physic

    Rare decay pi0 -> e+e-: theory confronts KTeV data

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    Within the dispersive approach to the amplitude of the rare decay pi0 -> e+e- the nontrivial dynamics is contained only in the subtraction constant. We express this constant, in the leading order in (m_e/\Lambda)^2 perturbative series, in terms of the inverse moment of the pion transition form factor given in symmetric kinematics. By using the CELLO and CLEO data on the pion transition form factor given in asymmetric kinematics the lower bound on the decay branching ratio is found. The restrictions following from QCD allow us to make a quantitative prediction for the branching B(pi0 -> e+e-) =(6.2\pm 0.1)*10^{-8} which is 3\sigma below the recent KTeV measurement. We confirm our prediction by using the quark models and phenomenological approaches based on the vector meson dominance. The decays \eta -> l^+l^- are also discussed.Comment: 7 pages, 1 figur

    Higgsless Electroweak Model and Contraction of Gauge Group

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    A modified formulation of the Electroweak Model with 3-dimensional spherical geometry in the target space is suggested. The {\it free} Lagrangian in the spherical field space along with the standard gauge field Lagrangian form the full Higgsless Lagrangian of the model, whose second order terms reproduce the same experimentally verified fields with the same masses as the Standard Electroweak Model. The vector bosons masses are automatically generated, so there is no need in special mechanism of spontaneous symmetry breaking. The limiting case of the modified Higgsless Electroweak Model, which corresponds to the contracted gauge group SU(2;j)×U(1)SU(2;j)\times U(1) is discussed. Within framework of the limit model Z-boson, electromagnetic and electron fields are interpreted as an external ones with respect to W-bosons and neutrino fields. The W-bosons and neutrino fields do not effect on these external fields. The masses of all particles remain the same, but the field interactions in contracted model are more simple as compared with the standard Electroweak Model due to nullification of some terms.Comment: Talk at the International Workshop "`Supersymmetries and Quantum Symmetries"' (SQS-09), Dubna, Russia, July 29 -- August 3, 2009, 11

    Ds0*(2317) and Ds1(2460) mesons in two-body B-meson decays

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    We analyze the branching ratios of B to D(*) + Ds0*(Ds1) decays using the factorization hypothesis. The B to D(*) transition form factors are taken from a model-independent analysis done by Caprini, Lellouch and Neubert based on heavy quark spin symmetry and dispersive constraints, including short-distance and power corrections. The leptonic decay constants fDs0* and fDs1 are calculated assuming a molecular structure for the Ds0* and Ds1 mesons. The calculated branching ratios of B-meson two-body decays are compared with experimental data and other theoretical results.Comment: 12 pages, 2 figure
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