Anastasia Golubtsova - Academia.edu (original) (raw)

Papers by Anastasia Golubtsova

$Research paper thumbnail of Circular strings in Kerr-$$AdS_{5}$$ black holes$

General Relativity and Gravitation

The quest for extension of holographic correspondence to the case of finite temperature naturally... more The quest for extension of holographic correspondence to the case of finite temperature naturally includes Kerr-AdS black holes and their field theory duals. In this paper we study the holography by probing the correspondence with pulsating strings. The case we consider is pulsating strings in the five-dimensional Kerr-AdS space time. First we find particular pulsating string solutions and then semi-classically quantize the theory. For the string with large values of energy, we use the Bohr-Sommerfeld analysis to find the energy of the string as a function of a large quantum number. We obtain the wave function of the problem and thoroughly study the corrections to the energy, which by duality are supposed to give anomalous dimensions of certain operators in the dual gauge theory. The interpretation of results from holographic point of view is not straightforward since the dual theory is at finite temperature. Nevertheless, near or at conformal point the expressions can be thought of as the dispersion relations of stationary states.

Nuclear Physics B

We continue to explore the dynamics of a heavy quark in a strongly coupled rotating quark-gluon p... more We continue to explore the dynamics of a heavy quark in a strongly coupled rotating quark-gluon plasma within the holographic framework. We use the 5d Kerr-AdS black hole with two arbitrary rotating parameters to describe the rotating quark-gluon plasma. We present the relations for the drag force acting on the heavy quark both in the rotating-and static-at-infinity frames for arbitrary choice of the rotational parameters. We also calculate the thermal mass of a static quark in different frames and show that at high-T limit the dependence on rotation is suppressed.

Observatoire de Paris, Sep 23, 2013

Pour un modèle gravitationnel D-dimensionnelle sur un produit de variétés d'Einstein, les sol... more Pour un modèle gravitationnel D-dimensionnelle sur un produit de variétés d'Einstein, les solutions exactes générales sont générées en utilisant l'approche modèle sigma lon-linéaire. Les solutions sont obtenues dans le cas suivant 1) tous les espaces sont à variétés à Ricci-plates, 2) un espace (l'espace quotient) à courbure scalaire non nul et les autres variétés sont Ricci-plates. Pour le premier cas, nous montrons que les solutions peuvent décrire l'expression accélérée de l'Univers. Une sous-classe de solutions à symétrie sphérique est étudiée. Les nouvelles solutions pour le modèle 4D de la théorie Brans-Dicke généralisée avec champs scalaires non-universallement couplés à la gravité sont trouvées en termes de fonctions elliptiques. Nous montrons que pour certains paramètres les solutions peuvent être exprimées en termes de fonctions exponentielles. Nous étudions des solutions de type cosmologique, qui ont une origine supergravitationnnel. Une sous-classe de S-branes correspondantes aux algèbres de Lie de rang 3 est choisi, pour cette sous-classe il existe un intervalle de temps où une expansion accélérée d'un sous-espace de dimension 3 est compatible avec une petite variation de la constante gravitationnelle. Les intersections orthogonales de trois M-branes sont étudiées par la SUGRA N=1 à 11D. Les formules explicites pour le calcul de supersymétries préservées sont obtenues. Certains exemples de configurations supersymétriques contenant les espaces K3, C /Z , une 4d pp-onde et R ' /Z sont présentés. Nous montrons que le remplacement de la variété plate avec topologie triviale par une variété Ricci-plate réduit le nombre des supersymétries préservées.For a D-dimensional gravitational model with a sigma-model source term, defined on a product of Einstein manifolds, the exact solutions of general type are generated using sigma model approach. The solutions are obtained in the following cases 1) when all factor spaces are Ricci-flat, 2) when one factor space has nonzero scalar curvature and other are Ricci-flat. For the first case we show that the solutions can describe the accelerated expansion of the Universe. A subclass of spherically-symmetric solutions is studied. "No-hair theorem" for black holes is proved. For the 4D model of the generalized Brans-Dicke gravity with scalar fields nonuniversally coupled to gravity, new solutions are found in terms of elliptic functions. We show that for certain parameters the solutions can be expressed in terms of exponential functions. Cosmological type solutions of supergravity origin are studied. A subslass of S-brane solutions corresponding to Lie algebras rank 3 is singled out, for which there exists a time interval where an accelerated expansion of a 3-dimensional subspace is compatible with a small enough value of the variation of the gravitational constant. For 11D N = 1 SUGRA orthogonal intersections of three M branes are studied. The explicit formulae for computing the amounts of preserved supersymmetries are obtained. Certain examples of the supersymmetric configurations containing such factor-spaces as K3, C /Z , a four dimensional pp-waves manifold and R ' /Z are presented. We show that the replacement of the flat manifold with trivial topology by a Ricci-flat manifold of a flat manifold with non trivial topology reduces the number of preserved supersymmeties.PARIS-Observatoire (751142302) / SudocSudocFranceF

arXiv: High Energy Physics - Theory, 2018

In this work an algorithm is proposed to calculate entropy for field theories living on NS five b... more In this work an algorithm is proposed to calculate entropy for field theories living on NS five branes, which gives a result invariant under T-duality. This is a deformation of the well known Ryu-Takayanagi formula, which takes into account dependence of localized backgrounds for the branes on winding modes of strings.

For a D-dimensional gravitational model with a sigma-model source term, defined on a product of E... more For a D-dimensional gravitational model with a sigma-model source term, defined on a product of Einstein manifolds, the exact solutions of general type are generated using sigma model approach. The solutions are obtained in the following cases 1) when all factor spaces are Ricci-flat, 2) when one factor space has nonzero scalar curvature and other are Ricci-flat. For the first case we show that the solutions can describe the accelerated expansion of the Universe. A subclass of spherically-symmetric solutions is studied. "No-hair theorem" for black holes is proved. For the 4D model of the generalized Brans-Dicke gravity with scalar fields nonuniversally coupled to gravity, new solutions are found in terms of elliptic functions. We show that for certain parameters the solutions can be expressed in terms of exponential functions. Cosmological type solutions of supergravity origin are studied. A subslass of S-brane solutions corresponding to Lie algebras rank 3 is singled out,...

Journal of High Energy Physics, 2021

We consider the 5d Kerr-AdS black hole as a gravity dual to rotating quark-gluon plasma. In the h... more We consider the 5d Kerr-AdS black hole as a gravity dual to rotating quark-gluon plasma. In the holographic prescription we calculate the drag force acting on a heavy quark. According to the holographic approach a heavy quark can be considered through the string in the gravity dual. We study the dynamics of the string for the Kerr-AdS backgrounds with one non-zero rotational parameter and two non-zero rotational parameters that are equal in magnitude. For the case of one non-zero rotational parameter we find good agreement with the prediction from the 4d case considered by arXiv:1012.3800.

Journal of Physics A: Mathematical and Theoretical, 2020

The quest for extension of holographic correspondence to non-relativistic sectors naturally inclu... more The quest for extension of holographic correspondence to non-relativistic sectors naturally includes Schrödinger backgrounds and their field theory duals. In this paper we study the holography by probing the correspondence with pulsating strings. The case we consider is pulsating strings in five-dimensional Schrödinger space times five-torus T 1,1 , which has as field theory dual a dipole CFT. First we find particular pulsating string solutions and then semi-classically quantize the theory. We obtain the wave function of the problem and thoroughly study the corrections to the energy, which by duality are supposed to give anomalous dimensions of certain operators in the dipole CFT.

Journal of High Energy Physics, 2020

We find explicit solutions for giant magnons and spiky strings living on the Schrödinger space Sc... more We find explicit solutions for giant magnons and spiky strings living on the Schrödinger space Schr5 × T1,1 and compute dispersion relations. The holographic dual field theory is conjectured to be a non-local dipole-deformed CFT at strong coupling. We find that the dependence between conserved charges in the dispersion relations is transcen- dental, which is quite different from the most symmetric case of spherical internal space. Keeping the squashing parameter b general allows us to take some limits and to compare our results to known cases.

Theoretical and Mathematical Physics, 2020

We study rectangular timelike Wilson loops at long distances in the exact renormalization group f... more We study rectangular timelike Wilson loops at long distances in the exact renormalization group flow in the context of the holographic duality. We consider the 5d holographic model with an exponential dilaton potential constructed in [arXiv:1803.06764]. To probe the RG flow backgrounds at zero and finite temperatures we calculate the minimal surfaces of the corresponding string worldsheets. We show that a holographic RG flow at T = 0 ,that mimics QCD behaviour of the running coupling, has a confining phase at long distances, while the RG flow with an AdS UV fixed point is non-confining.

Proceedings of Corfu Summer Institute 2016 "School and Workshops on Elementary Particle Physics and Gravity" — PoS(CORFU2016), 2017

In this note we study Wilson loops in an anisotropic black brane background within the holographi... more In this note we study Wilson loops in an anisotropic black brane background within the holographic framework. The anisotropy is controlled by the so called critical exponent. We calculate time-, space-and light-like static Wilson loops for different orientations of rectangular contours. The first two cases allow us to estimate behaviours of potential and pseudopotential of interquark interaction. We observe that the potential has a similar behaviour comparing to the potential for the isotropic (AdS) case, while the pseudopotential for a certain configuration of the contour has screened Coulomb and linear parts. For the light-like case we derive an analytic expression for the Nambo-Goto action for arbitrary values of the critical exponent.

Communications in Physics, 2019

We study Wilson loops in the exact renormalization group ow at zero tempera- ture via the 5d holo... more We study Wilson loops in the exact renormalization group ow at zero tempera- ture via the 5d holographic model that reproduces the behavior of the QCD running coupling. Calculating the time-like rectangular Wilson loop we show that the model includes a conning phase at T = 0 in the IR region.

Physical Review D, 2018

We study vacua and walls of mass-deformed Kähler nonlinear sigma models on Sp(N)/U (N). We identi... more We study vacua and walls of mass-deformed Kähler nonlinear sigma models on Sp(N)/U (N). We identify elementary walls with the simple roots of U Sp(2N) and discuss compressed walls, penetrable walls and multiwalls by using the moduli matrix formalism.

Journal of High Energy Physics, 2019

We construct analytic solutions of Einstein gravity coupled to a dilaton field with a potential g... more We construct analytic solutions of Einstein gravity coupled to a dilaton field with a potential given by a sum of two exponentials, by rewriting the equations of motion in terms of an integrable Toda chain. These solutions can be interpreted as domain walls interpolating between different asymptotics, and as such they can have interesting applications in holography. In some cases, we can construct a solution which interpolates between an AdS fixed point in the UV limit and a hyperscaling violating boundary in the IR region. We also find analytic black brane solutions at finite temperature. We discuss the properties of the solutions and the interpretation in terms of RG flow.

Journal of High Energy Physics, 2016

Using black brane solutions in 5d Lifshitz-like backgrounds with arbitrary dynamical exponent ν, ... more Using black brane solutions in 5d Lifshitz-like backgrounds with arbitrary dynamical exponent ν, we construct the Vaidya geometry, asymptoting to the Lifshitz-like spacetime, which represents a thin shell infalling at the speed of light. We apply the new Lifshitz-Vaidya background to study the thermalization process of the quark-gluon plasma via the thin shell approach previously successfully used in several backgrounds. We find that the thermalization depends on the chosen direction because of the spatial anisotropy. The plasma thermalizes thus faster in the transversal direction than in the longitudinal one. To probe the system described by the Lifshitz-like backgrounds, we also calculate the holographic entanglement entropy for the subsystems delineated along both transversal and longitudinal directions. We show that the entropy has some universality in the behavior for both subsystems. At the same time, we find that certain characteristics strongly depend on the critical exponent ν.

We present a description of computational program (written in Maple) for calculation of fluxbrane... more We present a description of computational program (written in Maple) for calculation of fluxbrane polynomials corresponding to classical simple Lie algebras. These polynomials define certain special solutions to open Toda chain equations.

The European Physical Journal C, 2014

We study a model of the generalized Brans-Dicke gravity presented in both the Jordan and in the E... more We study a model of the generalized Brans-Dicke gravity presented in both the Jordan and in the Einstein frames, which are conformally related. We show that the scalar field equations in the Einstein frame are reduced to the geodesics equations on the target space of the nonlinear sigma-model. The analytical solutions in elliptical functions are obtained when the conformal couplings are given by reciprocal exponential functions. The behavior of the scale factor in the Jordan frame is studied using numerical computations. For certain parameters the solutions can describe an accelerated expansion. We also derive an analytical approximation in exponential functions.

Gravitation and Cosmology, 2010

By means of a simple model we investigate the possibility of an accelerated expansion of a 3-dime... more By means of a simple model we investigate the possibility of an accelerated expansion of a 3-dimensional subspace in the presence of the variation of the effective 4-dimensional constant obeying the experimental constraint. Multidimensional cosmological solutions with m 2-form fields and l scalar fields are presented. Solutions corresponding to rank-3 Lie algebras are singled out and discussed. Each of solutions contain two factor spaces: one-dimensional space M 1 and Ricci-flat space M 2. A 3dimensional subspace of M 2 is interpreted as "our" space. We show that there exists a time interval where accelerated expansion of our 3D space is compatible with a small enough variation of the effective gravitational constant G(τ). This interval contains τ 0 which is the point of minimum of G(τ) (here τ is the synchronous time variable). Special solutions with three phantom scalar fields are analyzed. It is shown that in the vicinity of the point τ 0 the time variation of G(τ) decreases in the sequence of Lie algebras A 3 , C 3 and B 3 when the solutions with asymptotically power-law behavior of scale-factors for τ → ∞ are considered. Exact solutions with asymptotically exponential accelerated expansion of 3D space are also considered.

Gravitation and Cosmology, 2009

A multidimensional generalization of Melvin's solution for an arbitrary simple Lie algebra G is p... more A multidimensional generalization of Melvin's solution for an arbitrary simple Lie algebra G is presented. The gravitational model contains n 2-forms and l ≥ n scalar fields, where n is the rank of G. The solution is governed by a set of n functions obeying n ordinary differential equations with certain boundary conditions. It was conjectured earlier that these functions should be polynomials (the so-called fluxbrane polynomials). A program (in Maple) for calculating of these polynomials for classical series of Lie algebras is suggested (see Appendix). The polynomials corresponding to the Lie algebra D 4 are obtained. It is conjectured that the polynomials for A n-, B nand C n-series may be obtained from polynomials for D n+1-series by using certain reduction formulas.

Journal of High Energy Physics, 2015

We construct shock waves for Lifshitz-like geometries in four-and fivedimensional effective theor... more We construct shock waves for Lifshitz-like geometries in four-and fivedimensional effective theories as well as in D3-D7 and D4-D6 brane systems. The solutions to the domain wall profile equations are found. Further, the study makes a connection with the implications for the quark-gluon plasma formation in heavy-ion collisions. According to the holographic approach, the multiplicity of particles produced in heavy-ion collisions can be estimated by the area of the trapped surface formed in shock wave collisions. We calculate the areas of trapped surfaces in the geometry of two colliding Lifshitz domain walls. Our estimates show that for five-dimensional cases with certain values of the critical exponent the dependence of multiplicity on the energy of colliding ions is rather close to the experimental data M ∼ s 0.15 observed at RHIC and LHC.