38 research outputs found
Motivations for the Soft Wall holographic approach to strong interactions
No full textThe hypothesis of gauge/gravity correspondence (or holographic duality) from
string theory has led to unexpected and challenging ways for description of
strongly coupled systems. Such descriptions are given in terms of
weakly-coupled higher-dimensional gravitational theories. The holographic ideas
have penetrated many branches of theoretical physics. We discuss motivations
for the so-called Soft Wall holographic approach to non-perturbative strong
interactions and its advantages.Comment: 6 pages; Contribution to XVIII International Conference on Symmetry
Methods in Physics, 10-16 July, 2022, Erevan, Armeni
Gluon string breaking and meson spectrum in the holographic Soft Wall model
No full textWe propose a general method for finding a string-like meson spectrum which is
based on a certain condition for the breaking of closed gluon string. A model
is constructed that successfully realizes the proposed method. The model is
based on the holographic Soft Wall model for QCD and the use of the Wilson
confinement criterion. We applied our approach to the vector and scalar cases
and obtained numerical predictions for the intercepts of corresponding Regge
like radial meson spectra. A good agreement is obtained both with the existing
experimental data and with some other known phenomenological approaches.
Remarkably, our closed string breaking condition has two branches. We argue
that they should correspond to states of opposite parity. The Wilson
confinement criterion leads then to a natural mass splitting between parity
partners. The constructed model represents thus the first example of bottom-up
holographic model in which the effects of chiral symmetry breaking can emerge
automatically, i.e., without additional assumptions taken outside of the
holographic approach.Comment: 18 pages, 5 figures, v2: matches version published in PL
Confinement potential in Soft Wall holographic approach to QCD
No full textWe present the results for the confinement potential of the Cornell type
within the framework of the generalized Soft Wall holographic model (with
quadratic dilaton background in the metric) which contains an additional
parameter responsible for the value of intercept of the linear Regge spectrum.
Next, we note that the Cornell potential arises also in some Soft Wall models
which do not lead to Regge-like spectrum. As an example, we demonstrate this
property in a model with linear dilaton background in the metric. This example
is at odds with intuition based on the hadron string picture that the linearly
rising potential and Regge-like spectrum are directly related.Comment: 6 pages, contribution to the International Conference on Quantum
Field Theory, High-Energy Physics, and Cosmology (Dubna, Russian Federation,
July 2022
Confinement Potential in a Soft-Wall Holographic Model with a Hydrogen-like Spectrum
No full textIt is well known that the soft-wall holographic model for QCD successfully reproduces not only the linear Regge spectrum, but also, via the holographic Wilson confinement criterion, the “linear plus Coulomb” confinement potential, which is similar to the Cornell potential. This property could be interpreted as a holographic counterpart of the hadron string picture, where the linearly rising potential and Regge-like spectrum are directly related. However, such a relation does not exist in the bottom-up holographic approach. Namely, the Cornell-like potentials arise in a broad class of bottom-up holographic models. The standard soft-wall model is merely a particular representative of this class. This fact is relatively unknown, so we provide a comprehensive discussion of the point. As an example, we consider a soft-wall-like model with linear dilaton background in the metric. This model leads to a hydrogen-like spectrum. A “linear plus Coulomb” confinement potential within this model is calculated. The calculation of renormalized potential at short distances turns out to be complicated by a new subtlety that was skipped in general discussions of the issue existing in the literature. However, the confinement potential of the model is shown to be not very different from the potential obtained in the standard soft-wall model with a quadratic background
Dark matter production via a non-minimal coupling to gravity
No full textInternational audienceWe study postinflationary scalar dark matter production via its non-minimal coupling to gravity. During the inflaton oscillation epoch, dark matter is produced resonantly for a sufficiently large non-minimal coupling . We find that backreaction on the curvature and rescattering effects typically become important for the values of above , which invalidate simple estimates of the production efficiency. At large couplings, the dark matter yield becomes almost independent of , signifying approximate quasi-equilibrium in the inflaton-dark matter system. Although the analysis gets complicated by the presence of apparent negative energy in the Jordan frame, this behaviour can be regularized by introducing mild dark matter self-interaction. Using lattice simulations, we delineate parameter space leading to the correct dark matter relic abundance
Inflaton freeze-out
No full textWe study the possibility that, after inflation, the inflaton reaches thermal
equilibrium with the Standard Model thermal bath and eventually freezes-out in
the non-relativistic regime. When the inflaton decay is the sole source of
(non-thermal) dark matter, its relic density is automatically suppressed. We
delineate parameter space leading to the correct dark matter abundance. The
model allows for a significant Higgs-inflaton coupling which may lead to
invisible Higgs decay into inflaton pairs at the LHC.Comment: 14 pages, 3 figures; v2: matches version published in PRD (extended
discussions, fixed typos, updated references
Dark matter production and reheating via direct inflaton couplings : collective effects
No full textWe study scalar dark matter production and reheating via renormalizable inflaton couplings, which include both quartic and trilinear interactions. These processes often depend crucially on collective effects such as resonances, backreaction and rescattering of the produced particles. To take them into account, we perform lattice simulations and map out parameter space producing the correct (non-thermal) dark matter density. We find that the inflaton-dark matter system can reach a quasi-equilibrium state during preheating already at very small couplings, in which case the dark matter abundance becomes independent of the inflaton-dark matter coupling and is described by a universal formula. Dark matter is readily overproduced and even tiny values of the direct inflaton couplings can be sufficient to get the right composition of the Universe, which reaffirms their importance in cosmology.Peer reviewe
Бруно Латур и аналитическая эпистемология
No full textIn the article, the author examines the theory of knowledge of Bruno Latour from the perspective of analytic epistemology. Representatives of this approach-as well as Bruno Latour himself- are trying to answer the question: "What is knowledge?". The author explicates the difference between Latour's theory and the basic premises of the analytic epistemologists. In order to do this, the author highlights the theoretical foundations of Latour's theory of knowledge and demonstrates the conventions in the analysis of knowledge which this approach violates. Using the distinctions of analytic epistemology, the author classifies Latour's theory as a purist antisceptic invariantistic externalism. Such a theoretical position is one of the most common views on knowledge in this field. This classification of Latour's views makes it possible to identify the problems specific to this position. The author demonstrates that Latour's theory avoids some of these problems, that some of the problems have a solution specific to this theory, and that some of the problems are not specifically addressed within it. The advantage of Latour's theory is that it copes well with the two main challenges of analytic theories of knowledge: the Gettier problem and the prob- 117 lem of skepticism. In the conclusion, the author offers a critique specific to Latour's theory and presents possible objections to it
Formation of prerequisites for the renovationist schism among the liberal nobility and clergy of Orel guberniya in 1900–1917
No full textBased on the analysis of the periodicals of Orel guberniya of the early 20th century, as well as information on the public utterances of provincial public fi gures on the Church question in the pre-revolutionary period, the author reconstructs the process of formation of Renovationist schism among the liberal nobility and clergy of the province of Orel, trying to explain the presence of succession between the supporters of the reform of the Church in diff erent periods. The author also traces the emergence of ideas of Christian socialism in the province, which later became central to Soviet Renovationism. The study of the genesis of these ideas in the province during the period from the First Russian revolution to the February revolution makes it possible to understand the connection between religious and political factors in this dramatic period. When describing the events known to historians of the “Church revolution” of 1917 in Orel guberniya, the article draws on a unique material of personal origin, i.e. a detailed description of these events by one of the priests who was a participant and witness. The author of the article formulates his view on the processes of using the ideas of reforming the Church by various political parties from the Cadets to the Bolsheviks, finds a point of convergence of interests of those who fought for political power, and those who, being a certain stratum of the regional clergy, expressed their readiness to ensure the interests of the existing power, quickly changing their “patrons” if necessary. Moreover, attention is drawn to the facts of a rapid and radical change in the political position of certain representatives of Orel priesthood precisely during the implementation of serious revolutionary changes in the Russian state. The author was able to identify these names, specify them in the article and establish the diff erences between the schismatic element and those who really cared about the welfare of the Church
BANKING SECTOR MODERNIZATION(SPANISH RECIPE)
No full textThe aim of the research is to analyze transformation of the Spanish banking sector after the financial crisis of the year 2008. The author examines a hypothesis that banking system played an important role in the development of Spain’s economy. Spain’s banking sector was substantially transformed during the economic crisis, and now serves as a prerequisite for development of Spain’s national economy during post crisis perio
