Black Component of Dark Matter

A mechanism of primordial black hole formation with specific mass spectrum is discussed. It is shown that these black holes could contribute to the energy density of dark matter. Our approach is elaborated in the framework of universal extra dimensions

Threshold resummation for the production of a color sextet (antitriplet) scalar at the LHC

We investigate threshold resummation effects in the production of a color sextet (antitriplet) scalar at next-to-next-to-leading logarithmic (NNLL) order at the LHC in the frame of soft-collinear effective theory. We show the total cross section and the rapidity distribution with NLO+NNLL accuracy, and we compare them with the NLO results. Besides, we use recent dijet data at the LHC to give the constraints on the couplings between the colored scalars and quarks

Non-integrability in non-relativistic theories

Generic non-relativistic theories giving rise to non-integrable string solutions are classified. Our analysis boils down to a simple algebraic condition for the scaling parameters of the metric. Particular cases are the Lifshitz and the anisotropic Lifshitz spacetimes, for which we find that for trivial dilaton dependence the only integrable physical theory is that for z = 1. For the hyperscaling violation theories we conclude that the vast majority of theories are non-integrable, while only for a small class of physical theories, where the Fermi surfaces belong to, integrability is not excluded. Schrödinger theories are also analyzed and a necessary condition for non-integrability is found. Our analysis is also applied to cases where the exponential of the dilaton is a monomial of the holographic coordinate

Low energy description of quantum gravity and complementarity

We consider a framework in which low energy dynamics of quantum gravity is described preserving locality, and yet taking into account the effects that are not captured by the naive global spacetime picture, e.g. those associated with black hole complementarity. Our framework employs a “special relativistic” description of gravity; specifically, gravity is treated as a force measured by the observer tied to the coordinate system associated with a freely falling local Lorentz frame. We identify, in simple cases, regions of spacetime in which low energy local descriptions are applicable as viewed from the freely falling frame; in particular, we identify a surface called the gravitational observer horizon on which the local proper acceleration measured in the observer's coordinates becomes the cutoff (string) scale. This allows for separating between the “low-energy” local physics and “trans-Planckian” intrinsically quantum gravitational (stringy) physics, and allows for developing physical pictures of the origins of various effects. We explore the structure of the Hilbert space in which the proposed scheme is realized in a simple manner, and classify its elements according to certain horizons they possess. We also discuss implications of our framework on the firewall problem. We conjecture that the complementarity picture may persist due to properties of trans-Planckian physics

De Sitter space in gauge/gravity duality

We investigate gauge/gravity duality for gauge theories in de Sitter space. More precisely, we study a five-dimensional consistent truncation of type IIB supergravity, which encompasses a wide variety of gravity duals of strongly coupled gauge theories, including the Maldacena–Nunez solution and its walking deformations. We find several solutions of the 5d theory with dS4 spacetime and nontrivial profiles for (some of) the scalars along the fifth (radial) direction. In the process, we prove that one of the equations of motion becomes dependent on the others, for nontrivial warp factor. This dependence reduces the number of field equations and, thus, turns out to be crucial for the existence of solutions with (A)dS4 spacetime. Finally, we comment on the implications of our dS4 solutions for building gravity duals of Glueball Inflation

Holographic Rényi entropy in AdS 3 /LCFT 2 correspondence

The recent study in AdS 3 /CFT 2 correspondence shows that the tree level contribution and 1-loop correction of holographic Rényi entanglement entropy (HRE) exactly match the direct CFT computation in the large central charge limit. This allows the Rényi entanglement entropy to be a new window to study the AdS/CFT correspondence. In this paper we generalize the study of Rényi entanglement entropy in pure AdS 3 gravity to the massive gravity theories at the critical points. For the cosmological topological massive gravity (CTMG), the dual conformal field theory (CFT) could be a chiral conformal field theory or a logarithmic conformal field theory (LCFT), depending on the asymptotic boundary conditions imposed. In both cases, by studying the short interval expansion of the Rényi entanglement entropy of two disjoint intervals with small cross ratio x , we find that the classical and 1-loop HRE are in exact match with the CFT results, up to order x 6 . To this order, the difference between the massless graviton and logarithmic mode can be seen clearly. Moreover, for the cosmological new massive gravity (CNMG) at critical point, which could be dual to a logarithmic CFT as well, we find the similar agreement in the CNMG/LCFT correspondence. Furthermore we read the 2-loop correction of graviton and logarithmic mode to HRE from CFT computation. It has distinct feature from the one in pure AdS 3 gravity

D∗D¯∗ molecule interpretation of Zc(4025)

We have used QCD sum rules to study the newly observed charged state Zc(4025) as a hidden-charm D∗D¯∗ molecular state with the quantum numbers IG(JP)=1+(1+) . Using a D∗D¯∗ molecular interpolating current, we have calculated the two-point correlation function and the spectral density up to dimension eight at leading order in αs . The extracted mass is mX=(4.04±0.24) GeV. This result is compatible with the observed mass of Zc(4025) within the errors, which implies a possible molecule interpretation of this new resonance. We also predict the mass of the corresponding hidden-bottom B∗B¯∗ molecular state: mZb=(9.98±0.21) GeV

Higher harmonics of azimuthal anisotropy in relativistic heavy-ion collisions in HYDJET++ model

The LHC data on azimuthal anisotropy harmonics from PbPb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted in the framework of the HYDJET++ model. The cross-talk of elliptic <math><msub><mi>v</mi><mn>2</mn></msub></math> and triangular <math><msub><mi>v</mi><mn>3</mn></msub></math> flow in the model generates both even and odd harmonics of higher order. Comparison with the experimental data shows that this mechanism is able to reproduce the <math><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math> and centrality dependencies of quadrangular flow <math><msub><mi>v</mi><mn>4</mn></msub></math> , and also the basic trends for pentagonal <math><msub><mi>v</mi><mn>5</mn></msub></math> and hexagonal <math><msub><mi>v</mi><mn>6</mn></msub></math> flows

Inflationary paradigm after Planck 2013

Models of cosmic inflation posit an early phase of accelerated expansion of the universe, driven by the dynamics of one or more scalar fields in curved spacetime. Though detailed assumptions about fields and couplings vary across models, inflation makes specific, quantitative predictions for several observable quantities, such as the flatness parameter ( <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>Ω</mi></mrow><mrow><mi>k</mi></mrow></msub><mo>=</mo><mn>1</mn><mo>−</mo><mi>Ω</mi></math> ) and the spectral tilt of primordial curvature perturbations ( <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>n</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>−</mo><mn>1</mn><mo>=</mo><mi>d</mi><mi mathvariant="normal">ln</mi><mspace width="0.2em"/><msub><mrow><mi mathvariant="script">P</mi></mrow><mrow><mi mathvariant="script">R</mi></mrow></msub><mo stretchy="false">/</mo><mi>d</mi><mi mathvariant="normal">ln</mi><mspace width="0.2em"/><mi>k</mi></math> ), among others—predictions that match the latest observations from the Planck satellite to very good precision. In the light of data from Planck as well as recent theoretical developments in the study of eternal inflation and the multiverse, we address recent criticisms of inflation by Ijjas, Steinhardt, and Loeb. We argue that their conclusions rest on several problematic assumptions, and we conclude that cosmic inflation is on a stronger footing than ever before

Thermodynamics of two-dimensional conformal field theory dual to black holes

In this letter we investigate the first law of thermodynamics of the two-dimensional conformal field theory (CFT) that is dual to black holes. We start from the Cardy formula and get the CFT thermodynamics with minimal reasonable assumptions. We use both the microcanonical ensemble and canonical ensemble versions of the Cardy formula. In the black hole/CFT correspondence the black hole is dual to a CFT with excitations, and the black hole mass M and charge N correspond to the energy and charge of the excited CFT. The CFT left- and right-moving central charges <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>c</mi></mrow><mrow><mi>L</mi><mo>,</mo><mi>R</mi></mrow></msub></math> should be quantized, and so we assume that they are mass-independent. Also we assume the difference of the left- and right-moving sector levels <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>N</mi></mrow><mrow><mi>L</mi></mrow></msub></math> – <math altimg="si3.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>N</mi></mrow><mrow><mi>R</mi></mrow></msub></math> is mass-independent dual to level matching condition. The thermodynamics of two-dimensional CFT we get is universal and supports the thermodynamics method of black hole/CFT correspondence