Science.gov

Sample records for 7d anti-de sitter

  1. Blackfolds in (anti)-de Sitter backgrounds

    SciTech Connect

    Armas, Jay; Obers, Niels A.

    2011-04-15

    We construct different neutral blackfold solutions in Anti-de Sitter and de Sitter background spacetimes in the limit where the cosmological constant is taken to be much smaller than the horizon size. This includes a class of blackfolds with horizons that are products of odd-spheres times a transverse sphere, for which the thermodynamic stability is also studied. Moreover, we exhibit a specific case in which the same blackfold solution can describe different limiting black hole spacetimes therefore illustrating the geometric character of the blackfold approach. Furthermore, we show that the higher-dimensional Kerr-(Anti)-de Sitter black hole allows for ultraspinning regimes in the same limit under consideration and demonstrate that this is correctly described by a pancaked blackfold geometry. We also give evidence for the possibility of saturating the rigidity theorem in these backgrounds.

  2. The bizarre anti-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Sokołowski, Leszek M.

    2016-08-01

    Anti-de Sitter spacetime is important in general relativity and modern field theory. We review its geometrical features and properties of light signals and free particles moving in it. By applying only the elementary tools of tensor calculus, we derive ab initio of all these properties and show that they are really weird. One finds superluminal velocities of light and particles, infinite particle energy necessary to escape at infinite distance and spacetime regions inaccessible by a free fall, though reachable by an accelerated spaceship. Radial timelike geodesics are identical to the circular ones and actually all timelike geodesics are identical to one circle in a fictitious five-dimensional space. Employing the latter space, one is able to explain these bizarre features of anti-de Sitter spacetime; in this sense the spacetime is not self-contained. This is not a physical world.

  3. Colorful Horizons with Charge in Anti-de Sitter Space

    SciTech Connect

    Gubser, Steven S.

    2008-11-07

    An Abelian gauge symmetry can be spontaneously broken near a black hole horizon in anti-de Sitter space using a condensate of non-Abelian gauge fields. A second order phase transition is shown to separate Reissner-Nordstroem-anti-de Sitter solutions from a family of symmetry-breaking solutions which preserve a diagonal combination of gauge invariance and spatial rotational invariance.

  4. On electric field in anti-de Sitter spacetime

    SciTech Connect

    Cheong, Lee Yen E-mail: chewxy01813@gmail.com Yan, Chew Xiao E-mail: chewxy01813@gmail.com Ching, Dennis Ling Chuan E-mail: chewxy01813@gmail.com

    2014-10-24

    In this paper we calculate the electromagnetic field produced using retarded Green's function in Anti-de Sitter spacetime (AdS). Since this spacetime is non-globally hyperbolic and has no Cauchy surface, we only consider the field originated from a charge moving along its geodesic in the region consists of points covered by future null geodesic of the charge.

  5. Photon rockets in the (anti-)de Sitter universe

    SciTech Connect

    Podolsky, J.

    2008-08-15

    A class of exact solutions to Einstein's equations is presented, which describes accelerating photon rockets in the de Sitter and anti-de Sitter universes. These are particular members of the Robinson-Trautman family of axially symmetric spacetimes with pure radiation. In particular, generalizations of (type D) Kinnersley's rockets and (type II) Bonnor's rockets to the case of a nonvanishing cosmological constant are given. Some of the main physical properties of these solutions are investigated, and their relation to the C-metric solution which describes uniformly accelerated black holes is also given.

  6. Asymptotically anti-de Sitter spacetimes in topologically massive gravity

    SciTech Connect

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2009-04-15

    We consider asymptotically anti-de Sitter spacetimes in three-dimensional topologically massive gravity with a negative cosmological constant, for all values of the mass parameter {mu} ({mu}{ne}0). We provide consistent boundary conditions that accommodate the recent solutions considered in the literature, which may have a slower falloff than the one relevant for general relativity. These conditions are such that the asymptotic symmetry is in all cases the conformal group, in the sense that they are invariant under asymptotic conformal transformations and that the corresponding Virasoro generators are finite. It is found that, at the chiral point |{mu}l|=1 (where l is the anti-de Sitter radius), allowing for logarithmic terms (absent for general relativity) in the asymptotic behavior of the metric makes both sets of Virasoro generators nonzero even though one of the central charges vanishes.

  7. Weakly turbulent instability of anti-de Sitter spacetime.

    PubMed

    Bizoń, Piotr; Rostworowski, Andrzej

    2011-07-15

    We study the nonlinear evolution of a weakly perturbed anti-de Sitter (AdS) space by solving numerically the four-dimensional spherically symmetric Einstein-massless-scalar field equations with negative cosmological constant. Our results suggest that AdS space is unstable under arbitrarily small generic perturbations. We conjecture that this instability is triggered by a resonant mode mixing which gives rise to diffusion of energy from low to high frequencies.

  8. Dirac fermions on an anti-de Sitter background

    SciTech Connect

    Ambruş, Victor E. Winstanley, Elizabeth

    2014-11-24

    Using an exact expression for the bi-spinor of parallel transport, we construct the Feynman propagator for Dirac fermions in the vacuum state on anti-de Sitter space-time. We compute the vacuum expectation value of the stress-energy tensor by removing coincidence-limit divergences using the Hadamard method. We then use the vacuum Feynman propagator to compute thermal expectation values at finite temperature. We end with a discussion of rigidly rotating thermal states.

  9. Cosmic censorship of rotating Anti-de Sitter black hole

    SciTech Connect

    Gwak, Bogeun; Lee, Bum-Hoon E-mail: bhl@sogang.ac.kr

    2016-02-01

    We test the validity of cosmic censorship in the rotating anti-de Sitter black hole. For this purpose, we investigate whether the extremal black hole can be overspun by the particle absorption. The particle absorption will change the mass and angular momentum of the black hole, which is analyzed using the Hamilton-Jacobi equations consistent with the laws of thermodynamics. We have found that the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid.

  10. Lightlike hypersurfaces along spacelike submanifolds in anti-de Sitter space

    SciTech Connect

    Izumiya, Shyuichi

    2015-11-15

    Anti-de Sitter space is the Lorentzian space form with negative curvature. In this paper, we consider lightlike hypersurfaces along spacelike submanifolds in anti-de Sitter space with general codimension. In particular, we investigate the singularities of lightlike hypersurfaces as an application of the theory of Legendrian singularities.

  11. Generalized Gravitational Entropy for Warped Anti-de Sitter Space.

    PubMed

    Song, Wei; Wen, Qiang; Xu, Jianfei

    2016-07-01

    For spacetimes that are not asymptotic to anti-de Sitter (non AAdS) space, we adapt the Lewkowycz-Maldacena procedure to find the holographic entanglement entropy. The key observation, which to our knowledge is not very well appreciated, is that asymptotic boundary conditions play an essential role on extending the replica trick to the bulk. For non AAdS, we expect the following three main modifications: (1) the expansion near the special surface has to be compatible with the asymptotic expansion; (2) periodic conditions are imposed to coordinates on the phase space with diagonalized symplectic structure, not to all fields appearing in the action; (3) evaluating the entanglement functional using the boundary term method amounts to evaluating the presymplectic structure at the special surface, where some additional exact form may contribute. An explicit calculation is carried out for three-dimensional warped anti-de Sitter spacetime (WAdS_{3}) in a consistent truncation of string theory, the so-called S-dual dipole theory. It turns out that the generalized gravitational entropy in WAdS_{3} is captured by the least action of a charged particle in WAdS_{3} space, or equivalently, by the geodesic length in an auxiliary AdS_{3}. Consequently, the bulk calculation agrees with the CFT results, providing another piece of evidence for the WAdS_{3}/CFT_{2} correspondence.

  12. Generalized Gravitational Entropy for Warped Anti-de Sitter Space

    NASA Astrophysics Data System (ADS)

    Song, Wei; Wen, Qiang; Xu, Jianfei

    2016-07-01

    For spacetimes that are not asymptotic to anti-de Sitter (non AAdS) space, we adapt the Lewkowycz-Maldacena procedure to find the holographic entanglement entropy. The key observation, which to our knowledge is not very well appreciated, is that asymptotic boundary conditions play an essential role on extending the replica trick to the bulk. For non AAdS, we expect the following three main modifications: (1) the expansion near the special surface has to be compatible with the asymptotic expansion; (2) periodic conditions are imposed to coordinates on the phase space with diagonalized symplectic structure, not to all fields appearing in the action; (3) evaluating the entanglement functional using the boundary term method amounts to evaluating the presymplectic structure at the special surface, where some additional exact form may contribute. An explicit calculation is carried out for three-dimensional warped anti-de Sitter spacetime (WAdS3 ) in a consistent truncation of string theory, the so-called S -dual dipole theory. It turns out that the generalized gravitational entropy in WAdS3 is captured by the least action of a charged particle in WAdS3 space, or equivalently, by the geodesic length in an auxiliary AdS3 . Consequently, the bulk calculation agrees with the CFT results, providing another piece of evidence for the WAdS3/CFT2 correspondence.

  13. Holographic entanglement entropy for noncommutative anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Momeni, Davood; Raza, Muhammad; Myrzakulov, Ratbay

    2016-04-01

    A metric is proposed to explore the noncommutative form of the anti-de Sitter (AdS) space due to quantum effects. It has been proved that the noncommutativity in AdS space induces a single component gravitoelectric field. The holographic Ryu-Takayanagi (RT) algorithm is then applied to compute the entanglement entropy (EE) in dual CFT2. This calculation can be exploited to compute ultraviolet-infrared (UV-IR) cutoff dependent central charge of the certain noncommutative CFT2. This noncommutative computation of the EE can be interpreted in the form of the surface/state correspondence. We have shown that noncommutativity increases the dimension of the effective Hilbert space of the dual conformal field theory (CFT).

  14. Black hole microstates in anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Shaghoulian, Edgar

    2016-11-01

    We extend a recently derived higher-dimensional Cardy formula to include angular momenta, which we use to obtain the Bekensten-Hawking entropy of anti-de Sitter black branes, compactified rotating branes, and large Schwarzschild/Kerr black holes. This is the natural generalization of Strominger's microscopic derivation of the Banados-Teitelboim-Zanelli black hole entropy to higher dimensions. We propose an extension to include U (1 ) charge, which agrees with the Bekenstein-Hawking entropy of large Reissner-Nordstrom/Kerr-Newman black holes at high temperature. We extend the results to an arbitrary hyperscaling-violation exponent (this captures the case of black D p -branes as a subclass) and reproduce logarithmic corrections.

  15. A uniqueness theorem for the anti-de Sitter soliton.

    PubMed

    Galloway, G J; Surya, S; Woolgar, E

    2002-03-11

    The stability of physical systems depends on the existence of a state of least energy. In gravity, this is guaranteed by the positive energy theorem. For topological reasons, this fails for nonsupersymmetric Kaluza-Klein compactifications, which can decay to arbitrarily negative energy. For related reasons, this also fails for the anti-de Sitter (AdS) soliton, a globally static, asymptotically toroidal Lambda<0 spacetime with negative mass. Nonetheless, arguing from the AdS conformal field theory (AdS/CFT) correspondence, Horowitz and Myers proposed a new positive energy conjecture, which asserts that the AdS soliton is the unique state of least energy in its asymptotic class. We give a new structure theorem for static Lambda<0 spacetimes and use it to prove uniqueness of the AdS soliton. Our results offer significant support for the new positive energy conjecture and add to the body of rigorous results inspired by the AdS/CFT correspondence.

  16. Consistent higher derivative gravitational theories with stable de Sitter and anti-de Sitter backgrounds

    NASA Astrophysics Data System (ADS)

    Biswas, Tirthabir; Koshelev, Alexey S.; Mazumdar, Anupam

    2017-02-01

    In this paper we provide the criteria for any generally covariant, parity preserving, and torsion-free theory of gravity to possess a stable de Sitter (dS) or anti-de Sitter (AdS) background. By stability we mean the absence of tachyonic or ghostlike states in the perturbative spectrum that can lead to classical instabilities and violation of quantum unitarity. While we find that the usual suspects, the F (R ) and F (G ) theories, can indeed possess consistent (A)dS backgrounds, G being the Gauss-Bonnet term, another interesting class of theories, string-inspired infinite derivative gravitational theories, can also be consistent around such curved vacuum solutions. Our study should not only be relevant for quantum gravity and early universe cosmology involving ultraviolet physics, but also for modifications of gravity in the infrared sector vying to replace dark energy.

  17. Einstein-Maxwell-Anti-de-Sitter spinning solitons

    NASA Astrophysics Data System (ADS)

    Herdeiro, Carlos; Radu, Eugen

    2016-06-01

    Electrostatics on global Anti-de-Sitter (AdS) spacetime is sharply different from that on global Minkowski spacetime. It admits a multipolar expansion with everywhere regular, finite energy solutions, for every multipole moment except the monopole [1]. A similar statement holds for global AdS magnetostatics. We show that everywhere regular, finite energy, electric plus magnetic fields exist on AdS in three distinct classes: (I) with non-vanishing total angular momentum J; (II) with vanishing J but non-zero angular momentum density, Tφt; (III) with vanishing J and Tφt . Considering backreaction, these configurations remain everywhere smooth and finite energy, and we find, for example, Einstein-Maxwell-AdS solitons that are globally - Type I - or locally (but not globally) - Type II - spinning. This backreaction is considered first perturbatively, using analytical methods and then non-perturbatively, by constructing numerical solutions of the fully non-linear Einstein-Maxwell-AdS system. The variation of the energy and total angular momentum with the boundary data is explicitly exhibited for one example of a spinning soliton.

  18. Dynamical boundary for anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Krishnan, Chethan; Raju, Avinash; Subramanian, P. N. Bala

    2016-12-01

    We argue that a natural boundary condition for gravity in asymptotically anti-de Sitter (AdS) spaces is to hold the renormalized boundary stress tensor density fixed, instead of the boundary metric. This leads to a well-defined variational problem, as well as new counterterms and a finite on-shell action. We elaborate this in various (even and odd) dimensions in the language of holographic renormalization. Even though the form of the new renormalized action is distinct from the standard one, once the cutoff is taken to infinity, their values on classical solutions coincide when the trace anomaly vanishes. For AdS4 , we compute the Arnowitt-Deser-Misner form of this renormalized action and show in detail how the correct thermodynamics of Kerr-AdS black holes emerge. We comment on the possibility of a consistent quantization with our boundary conditions when the boundary is dynamical, and make a connection to the results of Compere and Marolf. The difference between our approach and microcanonical-like ensembles in standard AdS/CFT is emphasized.

  19. The fate of monsters in anti-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Ong, Yen Chin; Chen, Pisin

    2013-07-01

    Black hole entropy remains a deep puzzle: where does such enormous amount of entropy come from? Curiously, there exist gravitational configurations that possess even larger entropy than a black hole of the same mass, in fact, arbitrarily high entropy. These are the so-called monsters, which are problematic to the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence paradigm since there is far insufficient degrees of freedom on the field theory side to account for the enormous entropy of monsters in AdS bulk. The physics of the bulk however may be considerably modified at semi-classical level due to the presence of branes. We show that this is especially so since monster spacetimes are unstable due to brane nucleation. As a consequence, it is not clear what the final fate of monsters is. We argue that in some cases there is no real threat from monsters since although they are solutions to Einstein's Field Equations, they are very likely to be completely unstable when embedded in string theory, and thus probably are not solutions to the full quantum theory of gravity. Our analysis, while suggestive and supportive of the claim that such pathological objects are not allowed in the final theory, by itself does not rule out all monsters. We comment on various kin of monsters such as the "bag-of-gold" spacetime, and also discuss briefly the implications of our work to some puzzles related to black hole entropy.

  20. Semiclassical quantization of circular strings in de Sitter and anti--de Sitter spacetimes

    SciTech Connect

    de Vega, H.J. |; Larsen, A.L.; Sanchez, N.

    1995-06-15

    We compute the {ital exact} equation of state of circular strings in the (2+1)--dimensional de Sitter (dS) and anti--de Sitter (AdS) spacetimes, and analyze its properties for the different (oscillating, contracting, and expanding) strings. The string equation of state has the perfect fluid form {ital P}=({gamma}{minus}1){ital E}, with the pressure and energy expressed closely and completely in terms of elliptic functions, the instantaneous coefficient {gamma} depending on the elliptic modulus. We semiclassically quantize the oscillating circular strings. The string mass is {ital m}= {radical}{ital C} /({pi}{ital H}{alpha}{prime}), {ital C} being the Casimir operator, {ital C}={minus}{ital L}{sub {mu}{nu}}{ital L}{sup {mu}{nu}}, of the O(3,1)-dS [O(2,2)-AdS] group, and {ital H} is the Hubble constant. We find {alpha}{prime}{ital m}{sub dS}{sup 2}{approx}4{ital n}{minus}5{ital H}{sup 2}{alpha}{prime}{ital n}{sup 2} ({ital n}{element_of}{ital N}{sub 0}), and a {ital finite} number of states {ital N}{sub dS}{approx}0.34/({ital H}{sup 2}{alpha}{prime}) in de Sitter spacetime; {ital m}{sub AdS}{sup 2}{approx}{ital H}{sup 2}{ital n}{sup 2} (large {ital n}{element_of}{ital N}{sub 0}) and {ital N}{sub AdS}={infinity} in anti--de Sitter spacetime. The level spacing grows with {ital n} in AdS spacetime, while it is approximately constant (although smaller than in Minkowski spacetime and slightly decreasing) in dS spacetime. The massive states in dS spacetime decay through the tunnel effect and the semiclassical decay probability is computed. The semiclassical quantization of {ital exact} (circular) strings and the canonical quantization of generic string perturbations around the string center of mass qualitatively agree.

  1. Deformations of anti-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Detournay, Stephane

    2006-11-01

    This PhD thesis mainly deals with deformations of locally anti-de Sitter black holes, focusing in particular on BTZ black holes. We first study the generic rotating and (extended) non-rotating BTZ black holes within a pseudo-Riemannian symmetric spaces framework, emphasize on the role played by solvable subgroups of SL(2,R) in the black hole structure and derive their global geometry in a group-theoretical way. We analyse how these observations are transposed in the case of higher-dimensional locally AdS black holes. We then show that there exists, in SL(2,R), a family of twisted conjugacy classes which give rise to winding symmetric WZW D1-branes in a BTZ black hole background. The term "deformation" is then considered in two distinct ways. On the one hand, we deform the algebra of functions on the branes in the sense of (strict) deformation quantization, giving rise to a "noncommutative black hole". In the same context, we investigate the question of invariant deformations of the hyperbolic plane and present explicit formulae. On the other hand, we explore the moduli space of the (orbifolded) SL(2,R) WZW model by studying its marginal deformations, yielding namely a new class of exact black string solutions in string theory. These deformations also allow us to relate the D1-branes in BTZ black holes to D0-branes in the 2D black hole. A fair proportion of this thesis consists of (hopefully) pedagogical short introductions to various subjects: deformation quantization, string theory, WZW models, symmetric spaces, symplectic and Poisson geometry.

  2. Phase space localization for anti-de Sitter quantum mechanics and its zero curvature limit

    NASA Technical Reports Server (NTRS)

    Elgradechi, Amine M.

    1993-01-01

    Using techniques of geometric quantization and SO(sub 0)(3,2)-coherent states, a notion of optimal localization on phase space is defined for the quantum theory of a massive and spinning particle in anti-de Sitter space time. It is shown that this notion disappears in the zero curvature limit, providing one with a concrete example of the regularizing character of the constant (nonzero) curvature of the anti-de Sitter space time. As a byproduct a geometric characterization of masslessness is obtained.

  3. Tunneling between de Sitter and anti-de Sitter black holes in a noncommutative D{sub 3}-brane formalism

    SciTech Connect

    Kar, Supriya

    2006-12-15

    We obtain de Sitter (dS) and anti-de Sitter (AdS) generalized Reissner-Nordstrom-like black hole geometries in a curved D{sub 3}-brane framework, underlying a noncommutative gauge theory on the brane world. The noncommutative scaling limit is explored to investigate a possible tunneling of an AdS vacuum in string theory to dS vacuum in its low energy gravity theory. The Hagedorn transition is invoked into its self-dual gauge theory to decouple the gauge nonlinearity from the dS geometry, which in turn is shown to describe a pure dS vacuum.

  4. Discrete Torsion, (Anti) de Sitter D4-Brane and Tunneling

    NASA Astrophysics Data System (ADS)

    Singh, Abhishek K.; Pandey, P. K.; Singh, Sunita; Kar, Supriya

    2014-06-01

    We obtain quantum geometries on a vacuum created pair of a (DDbar)3-brane, at a Big Bang singularity, by a local two form on a D4-brane. In fact our analysis is provoked by an established phenomenon leading to a pair creation by a gauge field at a black hole horizon by Stephen Hawking in 1975. Importantly, the five dimensional microscopic black holes are described by an effective non-perturbative curvature underlying a discrete torsion in a second order formalism. In the case for a non-propagating torsion, the effective curvature reduces to Riemannian, which in a low energy limit may describe Einstein vacuum in the formalism. In particular, our analysis suggests that a non-trivial space begin with a hot de Sitter brane-Universe underlying a nucleation of a vacuum pair of (DDbar)-instanton at a Big Bang. A pair of instanton nucleats a D-particle which in turn combines with an anti D-particle to describe a D-string and so on. The nucleation of a pair of higher dimensional pair of brane/anti-brane from a lower dimensional pair may be viewed via an expansion of the brane-Universe upon time. It is in conformity with the conjecture of a branes within a brane presumably in presence of the non-zero modes of two form. Interestingly, we perform a thermal analysis underlying various emergent quantum de Sitter vacua on a D4-brane and argue for the plausible tunneling geometries underlying a thermal equilibrium. It is argued that a de Sitter Schwarzschild undergoes quantum tunneling to an AdS-brane Schwarzschild via Nariai and de Sitter topological black hole.

  5. Delayed collapses of Bose-Einstein condensates in relation to anti-de Sitter gravity

    NASA Astrophysics Data System (ADS)

    Biasi, Anxo F.; Mas, Javier; Paredes, Angel

    2017-03-01

    We numerically investigate spherically symmetric collapses in the Gross-Pitaevskii equation with attractive nonlinearity in a harmonic potential. Even below threshold for direct collapse, the wave function bounces off from the origin and may eventually become singular after a number of oscillations in the trapping potential. This is reminiscent of the evolution of Einstein gravity sourced by a scalar field in anti de Sitter space where collapse corresponds to black-hole formation. We carefully examine the long time evolution of the wave function for continuous families of initial states in order to sharpen out this qualitative coincidence which may bring new insights in both directions. On the one hand, we comment on possible implications for the so-called Bosenova collapses in cold atom Bose-Einstein condensates. On the other hand, Gross-Pitaevskii provides a toy model to study the relevance of either the resonance conditions or the nonlinearity for the problem of anti de Sitter instability.

  6. Hawking radiation from general Kerr-(anti)de Sitter black holes

    SciTech Connect

    Xu Zhibo; Chen Bin

    2007-01-15

    We calculate the total flux of Hawking radiation from Kerr-(anti)de Sitter black holes by using gravitational anomaly method developed in [S. P. Robinson and F. Wilczek, Phys. Rev. Lett. 95, 011303 (2005)]. We consider the general Kerr-(anti)de Sitter black holes in arbitrary D dimensions with the maximal number [D/2] of independent rotating parameters. We find that the physics near the horizon can be described by an infinite collection of (1+1)-dimensional quantum fields coupled to a set of gauge fields with charges proportional to the azimuthal angular momentums m{sub i}. With the requirement of anomaly cancellation and regularity at the horizon, the Hawking radiation is determined.

  7. Stability of anti-de sitter space in Einstein-Gauss-Bonnet gravity.

    PubMed

    Deppe, Nils; Kolly, Allison; Frey, Andrew; Kunstatter, Gabor

    2015-02-20

    Recently it has been argued that in Einstein gravity anti-de Sitter spacetime is unstable against the formation of black holes for a large class of arbitrarily small perturbations. We examine the effects of including a Gauss-Bonnet term. In five dimensions, spherically symmetric Einstein-Gauss-Bonnet gravity has two key features: Choptuik scaling exhibits a radius gap, and the mass function goes to a finite value as the horizon radius vanishes. These suggest that black holes will not form dynamically if the total mass-energy content of the spacetime is too small, thereby restoring the stability of anti-de Sitter spacetime in this context. We support this claim with numerical simulations and uncover a rich structure in horizon radii and formation times as a function of perturbation amplitude.

  8. Collision of domain walls in asymptotically anti-de Sitter spacetime

    SciTech Connect

    Takamizu, Yu-ichi; Maeda, Kei-ichi

    2006-05-15

    We study collision of two domain walls in five-dimensional asymptotically anti-de Sitter spacetime. This may provide the reheating mechanism of an ekpyrotic (or cyclic) brane universe, in which two Bogomol'nyi-Prasad-Sommerfield branes collide and evolve into a hot big bang universe. We evaluate a change of scalar field making the domain wall and can investigate the effect of a negative cosmological term in the bulk to the collision process and the evolution of our universe.

  9. Resonant Dynamics and the Instability of Anti-de Sitter Spacetime.

    PubMed

    Bizoń, Piotr; Maliborski, Maciej; Rostworowski, Andrzej

    2015-08-21

    We consider spherically symmetric Einstein-massless-scalar field equations with a negative cosmological constant in five dimensions and analyze the evolution of small perturbations of anti-de Sitter (AdS) spacetime using the recently proposed resonant approximation. We show that for typical initial data the solution of the resonant system develops an oscillatory singularity in finite time. This result hints at a possible route to establishing the instability of AdS under arbitrarily small perturbations.

  10. Noncommutative geometry inspired -dimensional charged black hole solution in an anti-de Sitter background spacetime

    NASA Astrophysics Data System (ADS)

    Rahaman, Farook; Bhar, Piyali; Sharma, Ranjan; Tiwari, Rishi Kumar

    2015-03-01

    We report a -D charged black hole solution in an anti-de Sitter space inspired by noncommutative geometry. In this construction, the black hole exhibits two horizons, which turn into a single horizon in the extreme case. We investigate the impacts of electromagnetic field on the location of the event horizon, mass and thermodynamic properties such as Hawking temperature, entropy, and heat capacity of the black hole. The geodesics of the charged black hole are also analyzed.

  11. Conservation laws for classical particles in anti-de Sitter-Beltrami space

    NASA Astrophysics Data System (ADS)

    Angsachon, T.; Manida, S. N.; Tchaikovskii, M. E.

    2013-07-01

    The behavior of free classical pointlike particles is governed by conservation laws in the anti-de Sitter space. We present the general form of these laws and their realization in the Beltrami coordinates. In these coordinates, we can pass to the nonrelativistic limit resulting in physics in the R space. We construct the initial covariant distribution function for an ideal gas uniformly filling the entire R space.

  12. Anti-de Sitter quantum field theory and the AdS-CFT correspondence

    NASA Astrophysics Data System (ADS)

    Moschella, U.

    We give a short account of a new approach to anti-de Sitter quantum field theory that is based on the assumption of certain analyticity properties of the n-point correlation functions. We then discuss the application of this formalism to the construction of conformal field theories that are naturally obtained on the covering of the cone asymptotic to the AdS manifold, and that satisfy the axioms of Luscher and Mack.

  13. Recursive Techniques for Computing Gluon Scattering in Anti-de-Sitter Space

    NASA Astrophysics Data System (ADS)

    Shyaka, Claude; Kharel, Savan

    2016-03-01

    The anti-de Sitter/conformal field theory correspondence is a relationship between two kinds of physical theories. On one side of the duality are special type of quantum (conformal) field theories known as the Yang-Mills theory. These quantum field theories are known to be equivalent to theories of gravity in Anti-de Sitter (AdS) space. The physical observables in the theory are the correlation functions that live in the boundary of AdS space. In general correlation functions are computed using configuration space and the expressions are extremely complicated. Using momentum basis and recursive techniques developed by Raju, we extend tree level correlation functions for four and five-point correlation functions in Yang-Mills theory in Anti-de Sitter space. In addition, we show that for certain external helicity, the correlation functions have simple analytic structure. Finally, we discuss how one can generalize these results to n-point functions. Hendrix college odyssey Grant.

  14. LETTER TO THE EDITOR: Asymptotically anti-de Sitter spacetimes: conserved quantities

    NASA Astrophysics Data System (ADS)

    Ashtekar, Abhay; Das, Saurya

    2000-01-01

    Asymptotically anti-de Sitter spacetimes are considered in a general dimension dicons/Journals/Common/ge" ALT="ge" ALIGN="TOP"/> 4. As one might expect, the boundary conditions at infinity ensure that the asymptotic symmetry group is the anti-de Sitter group (although there is an interesting subtlety if d = 4). Asymptotic field equations imply that, associated with each generator icons/Journals/Common/xi" ALT="xi" ALIGN="TOP"/> of this group, there is a quantity Qicons/Journals/Common/xi" ALT="xi" ALIGN="MIDDLE"/> which satisfies the expected `balance equation' if there is a flux of physical matter fields across the boundary icons/Journals/Common/calI" ALT="calI" ALIGN="TOP"/> at infinity and is absolutely conserved in the absence of this flux. Irrespective of the dimension d , all of these quantities vanish if the spacetime under considerations is (globally) anti-de Sitter. Furthermore, this result is required by a general covariance argument. However, it contradicts some of the recent findings based on the conjectured ADS/CFT duality. This and other features of our analysis suggest that, if a consistent dictionary between gravity and conformal field theories does exist in fully non-perturbative regimes, it would have to be more subtle than the one used currently.

  15. Raising anti-de Sitter vacua to de Sitter vacua in heterotic M theory

    SciTech Connect

    Buchbinder, Evgeny I.

    2004-09-15

    We explore the possibility of obtaining de Sitter vacua in strongly coupled heterotic models by adding various corrections to the supergravity potential energy. We show that, in a generic compactification scenario, Fayet-Iliopoulos terms can generate a de Sitter vacuum. The cosmological constant in this vacuum can be fine tuned to be consistent with observation. We also study moduli potentials in nonsupersymmetric compactifications of E{sub 8}xE{sub 8} theory with anti five-branes and E{sub 8}xE{sub 8} theory. We argue that they can be used to create a de Sitter vacuum only if some of the Kahler structure moduli are stabilized at values much less than the Calabi-Yau scale.

  16. Toroidal configurations of perfect fluid in the Reissner-Nordström-(anti-)de Sitter spacetimes

    SciTech Connect

    Kucáková, Hana; Slaný, Petr; Stuchlík, Zdenĕk E-mail: petr.slany@fpf.slu.cz

    2011-01-01

    Influence of cosmological constant on toroidal fluid configurations around charged spherically symmetric black holes and naked singularities is demostrated by study of perfect-fluid tori with uniform distribution of specific angular momentum orbiting in the Reissner-Nordström-(anti-)de Sitter spacetimes. Toroidal configurations are allowed only in the spacetimes admitting existence of stable circular geodesics. Configurations with marginally closed equipotential (equipressure) surfaces crossing itself in a cusp allow accretion (through the inner cusp) and/or excretion (through the outer cusp) of matter from the toroidal configuration. Detailed classification of the Reissner-Nordström-(anti-)de Sitter spacetimes according to properties of the marginally stable tori is given. It is demonstrated that in the Reissner-Nordström-de Sitter naked-singularity spacetimes an interesting phenomenon of doubled tori can exist enabling exchange of matter between two tori in both inward and outward directions. In naked-singularity spacetimes the accretion onto the central singularity is impossible due to existence of a potential barrier.

  17. Analytical solution of the geodesic equation in Kerr-(anti-) de Sitter space-times

    SciTech Connect

    Hackmann, Eva; Laemmerzahl, Claus; Kagramanova, Valeria; Kunz, Jutta

    2010-02-15

    The complete analytical solutions of the geodesic equations in Kerr-de Sitter and Kerr-anti-de Sitter space-times are presented. They are expressed in terms of Weierstrass elliptic p, {zeta}, and {sigma} functions as well as hyperelliptic Kleinian {sigma} functions restricted to the one-dimensional {theta} divisor. We analyze the dependency of timelike geodesics on the parameters of the space-time metric and the test-particle and compare the results with the situation in Kerr space-time with vanishing cosmological constant. Furthermore, we systematically can find all last stable spherical and circular orbits and derive the expressions of the deflection angle of flyby orbits, the orbital frequencies of bound orbits, the periastron shift, and the Lense-Thirring effect.

  18. Generic cosmic-censorship violation in anti-de Sitter space.

    PubMed

    Hertog, Thomas; Horowitz, Gary T; Maeda, Kengo

    2004-04-02

    We consider (four-dimensional) gravity coupled to a scalar field with potential V(phi). The potential satisfies the positive energy theorem for solutions that asymptotically tend to a negative local minimum. We show that for a large class of such potentials, there is an open set of smooth initial data that evolve to naked singularities. Hence cosmic censorship does not hold for certain reasonable matter theories in asymptotically anti-de Sitter spacetimes. The asymptotically flat case is more subtle. We suspect that potentials with a local Minkowski minimum may similarly lead to violations of cosmic censorship in asymptotically flat spacetimes, but we do not have definite results.

  19. Anyonic Strings and Membranes in Anti-de Sitter Space and Dual Aharonov-Bohm Effects

    SciTech Connect

    Hartnoll, Sean A.

    2007-03-16

    It is observed that strings in AdS{sub 5}xS{sup 5} and membranes in AdS{sub 7}xS{sup 4} exhibit long range phase interactions. Two well separated membranes dragged around one another in anti-de Sitter space (AdS) acquire phases of 2{pi}/N. The same phases are acquired by a well separated F and D string dragged around one another. The phases are shown to correspond to both the standard and a novel type of Aharonov-Bohm effect in the dual field theory.

  20. Anyonic strings and membranes in anti-de Sitter space and dual Aharonov-Bohm effects.

    PubMed

    Hartnoll, Sean A

    2007-03-16

    It is observed that strings in AdS(5) x S(5) and membranes in AdS(7) x S(4) exhibit long range phase interactions. Two well separated membranes dragged around one another in anti-de Sitter space (AdS) acquire phases of 2 pi/N. The same phases are acquired by a well separated F and D string dragged around one another. The phases are shown to correspond to both the standard and a novel type of Aharonov-Bohm effect in the dual field theory.

  1. A note on conformally compactified connection dynamics tailored for anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Bodendorfer, N.

    2016-12-01

    A framework conceptually based on the conformal techniques employed to study the structure of the gravitational field at infinity is set up in the context of loop quantum gravity to describe asymptotically anti-de Sitter quantum spacetimes. A conformal compactification of the spatial slice is performed, which, in terms of the rescaled metric, has now finite volume, and can thus be conveniently described by spin networks states. The conformal factor used is a physical scalar field, which has the necessary asymptotics for many asymptotically AdS black hole solutions.

  2. Classical Yang-Mills Black Hole Hair in Anti-de Sitter Space

    NASA Astrophysics Data System (ADS)

    Winstanley, E.

    The properties of hairy black holes in Einstein-Yang-Mills (EYM) theory are reviewed, focusing on spherically symmetric solutions. In particular, in asymptotically anti-de Sitter space (adS) stable black hole hair is known to exist for frak su(2) EYM. We review recent work in which it is shown that stable hair also exists in frak su(N) EYM for arbitrary N, so that there is no upper limit on how much stable hair a black hole in adS can possess.

  3. Extended Anti-de Sitter Hypergravity in 2 + 1 Dimensions and Hypersymmetry Bounds

    NASA Astrophysics Data System (ADS)

    Henneaux, Marc; Pérez, Alfredo; Tempo, David; Troncoso, Ricardo

    In a recent paper (JHEP 1508 (2015) 021), we have investigated hypersymmetry bounds in the context of simple anti-de Sitter hypergravity in 2+1 dimensions. We showed that these bounds involved non linearly the spin-2 and spin-4 charges, and were saturated by a class of extremal black holes, which are 1/4-hypersymmetric. We continue the analysis here by considering (M,N)-extended anti-de Sitter hypergravity models, based on the superalgebra osp(M|4) ⊕ osp(N|4). The asymptotic symmetry superalgebra is then the direct sum of two-copies of a W-superalgebra that contains so(M) (or so(N)) Kac-Moody currents of conformal weight 1, fermionic generators of conformal weight 5/2 and bosonic generators of conformal weight 4 in addition to the Virasoro generators. The nonlinear hypersymmetry bounds on the conserved charges are derived and shown to be saturated by a class of extreme hypersymmetric black holes which we explicitly construct.

  4. The Hawking-Page crossover in noncommutative anti-deSitter space

    NASA Astrophysics Data System (ADS)

    Nicolini, Piero; Torrieri, Giorgio

    2011-08-01

    We study the problem of a Schwarzschild-anti-deSitter black hole in a non-commutative geometry framework, thought to be an effective description of quantum-gravitational spacetime. As a first step we derive the noncommutative geometry inspired Schwarzschild-anti-deSitter solution. After studying the horizon structure, we find that the curvature singularity is smeared out by the noncommutative fluctuations. On the thermodynamics side, we show that the black hole temperature, instead of a divergent behavior at small scales, admits a maximum value. This fact implies an extension of the Hawking-Page transition into a van der Waals-like phase diagram, with a critical point at a critical cosmological constant size in Plank units and a smooth crossover thereafter. We speculate that, in the gauge-string dictionary, this corresponds to the confinement "critical point" in number of colors at finite number of flavors, a highly non-trivial parameter that can be determined through lattice simulations.

  5. Massless and massive higher spins from anti-de Sitter space waveguide

    NASA Astrophysics Data System (ADS)

    Gwak, Seungho; Kim, Jaewon; Rey, Soo-Jong

    2016-11-01

    Understanding Higgs mechanism for higher-spin gauge fields is an outstanding open problem. We investigate this problem in the context of Kaluza-Klein compactification. Starting from a free massless higher-spin field in ( d + 2)-dimensional anti-de Sitter space and compactifying over a finite angular wedge, we obtain an infinite tower of heavy, light and massless higher-spin fields in ( d + 1)-dimensional anti-de Sitter space. All massive higher-spin fields are described gauge invariantly in terms of Stueckelberg fields. The spectrum depends on the boundary conditions imposed at both ends of the wedges. We observed that higher-derivative boundary condition is inevitable for spin greater than three. For some higher-derivative boundary conditions, equivalently, spectrum-dependent boundary conditions, we get a non-unitary representation of partially-massless higher-spin fields of varying depth. We present intuitive picture which higher-derivative boundary conditions yield non-unitary system in terms of boundary action. We argue that isotropic Lifshitz interfaces in O( N ) Heisenberg magnet or O( N ) Gross-Neveu model provides the holographic dual conformal field theory and propose experimental test of (inverse) Higgs mechanism for massive and partially massless higher-spin fields.

  6. Asymptotically (anti)-de Sitter solutions in Gauss-Bonnet gravity without a cosmological constant

    SciTech Connect

    Dehghani, M.H.

    2004-09-15

    In this paper I show that one can have asymptotically de Sitter, anti-de Sitter (AdS), and flat solutions in Gauss-Bonnet gravity without a cosmological constant term in field equations. First, I introduce static solutions whose three surfaces at fixed r and t have constant positive (k=1), negative (k=-1), or zero (k=0) curvature. I show that for k={+-}1 one can have asymptotically de Sitter, AdS, and flat spacetimes, while for the case of k=0, one has only asymptotically AdS solutions. Some of these solutions present naked singularities, while some others are black hole or topological black hole solutions. I also find that the geometrical mass of these five-dimensional spacetimes is m+2{alpha}|k|, which is different from the geometrical mass m of the solutions of Einstein gravity. This feature occurs only for the five-dimensional solutions, and is not repeated for the solutions of Gauss-Bonnet gravity in higher dimensions. Second, I add angular momentum to the static solutions with k=0, and introduce the asymptotically AdS charged rotating solutions of Gauss-Bonnet gravity. Finally, I introduce a class of solutions which yields an asymptotically AdS spacetime with a longitudinal magnetic field, which presents a naked singularity, and generalize it to the case of magnetic rotating solutions with two rotation parameters.

  7. Simulation of black hole collisions in asymptotically Anti-de Sitter spacetimes.

    PubMed

    Bantilan, Hans; Romatschke, Paul

    2015-02-27

    We present results from the evolution of spacetimes that describe the merger of asymptotically global anti-de Sitter black holes in 5D with an SO(3) symmetry. Prompt scalar field collapse provides us with a mechanism for producing distinct trapped regions on the initial slice, associated with black holes initially at rest. We evolve these black holes towards a merger, and follow the subsequent ring down. The boundary stress tensor of the dual conformal field theory is conformally related to a stress tensor in Minkowski space that inherits an axial symmetry from the bulk SO(3). We compare this boundary stress tensor to its hydrodynamic counterpart with viscous corrections of up to second order, and compare the conformally related stress tensor to ideal hydrodynamic simulations in Minkowski space, initialized at various time slices of the boundary data. Our findings reveal far-from-hydrodynamic behavior at early times, with a transition to ideal hydrodynamics at late times.

  8. Nonlinear Evolution and Final Fate of Charged Anti-de Sitter Black Hole Superradiant Instability.

    PubMed

    Bosch, Pablo; Green, Stephen R; Lehner, Luis

    2016-04-08

    We describe the full nonlinear development of the superradiant instability for a charged massless scalar field coupled to general relativity and electromagnetism, in the vicinity of a Reissner-Nordström-anti-de Sitter black hole. The presence of the negative cosmological constant provides a natural context for considering perfectly reflecting boundary conditions and studying the dynamics as the scalar field interacts repeatedly with the black hole. At early times, small superradiant perturbations grow as expected from linearized studies. Backreaction then causes the black hole to lose charge and mass until the perturbation becomes nonsuperradiant, with the final state described by a stable hairy black hole. For large gauge coupling, the instability extracts a large amount of charge per unit mass, resulting in greater entropy increase. We discuss the implications of the observed behavior for the general problem of superradiance in black hole spacetimes.

  9. Thermodynamics and phase transitions in the Born-Infeld-anti-de Sitter black holes

    SciTech Connect

    Myung, Yun Soo; Kim, Yong-Wan; Park, Young-Jai

    2008-10-15

    We investigate the Born-Infeld-anti-de Sitter (BIAdS) black hole solutions in the four dimensions, which is a nonlinear generalization of the Reissner-Norstroem-AdS (RNAdS) black hole. We analyze all thermodynamic quantities of the BIAdS black hole in the canonical ensembles, which are characterized by the charge Q, the mass M, the nonlinear parameter b, comparing with those of the RNAdS and Schwarzschild-AdS black hole. We find the forbidden region of 0{<=}bQ<0.5 for the presence of a charged BIAdS black hole. We also discuss the Hawking-Page phase transitions in the BIAdS black holes. Here we obtain a new Hawking-Page phase transition for the bQ=0.5 critical BIAdS black hole.

  10. Unique Continuation from Infinity in Asymptotically Anti-de Sitter Spacetimes

    NASA Astrophysics Data System (ADS)

    Holzegel, Gustav; Shao, Arick

    2016-11-01

    We consider the unique continuation properties of asymptotically anti-de Sitter spacetimes by studying Klein-Gordon-type equations {Box_g φ + σ φ = {G} ( φ, partial φ )}, {σ in {R}}, on a large class of such spacetimes. Our main result establishes that if {φ} vanishes to sufficiently high order (depending on {σ}) on a sufficiently long time interval along the conformal boundary I, then the solution necessarily vanishes in a neighborhood of I. In particular, in the {σ}-range where Dirichlet and Neumann conditions are possible on I for the forward problem, we prove uniqueness if both these conditions are imposed. The length of the time interval can be related to the refocusing time of null geodesics on these backgrounds and is expected to be sharp. Some global applications as well as a uniqueness result for gravitational perturbations are also discussed. The proof is based on novel Carleman estimates established in this setting.

  11. The Derivation and Quasinormal Mode Spectrum of Acoustic Anti-de Sitter Black Hole Analogues

    NASA Astrophysics Data System (ADS)

    Babb, James Patrick

    Dumb holes (also known as acoustic black holes) are fluid flows which include an "acoustic horizon": a surface, analogous to a gravitational horizon, beyond which sound may pass but never classically return. Soundwaves in these flows will therefore experience "effective geometries" which are identical to black hole spacetimes up to a conformal factor. By adjusting the parameters of the fluid flow, it is possible to create an effective geometry which is conformal to the Anti-de Sitter black hole spacetime---a geometry which has received a great deal of attention in recent years due to its conjectured holographic duality to Conformal Field Theories. While we would not expect an acoustic analogue of the AdS-CFT correspondence to exist, this dumb hole provides a means, at least in principle, of experimentally testing the theoretical properties of the AdS spacetime. In particular, I have calculated the quasinormal mode spectrum of this acoustic geometry.

  12. Noncommutative brane-world, (Anti) de Sitter vacua and extra dimensions

    NASA Astrophysics Data System (ADS)

    Kar, Supriya

    2006-10-01

    We investigate a curved brane-world, inspired by a noncommutative D3-brane, in a type IIB string theory. We obtain, an axially symmetric and a spherically symmetric, (anti) de Sitter black holes in 4D. The event horizons of these black holes possess a constant curvature and may be seen to be governed by different topologies. The extremal geometries are explored, using the noncommutative scaling in the theory, to reassure the attractor behavior at the black hole event horizon. The emerging two dimensional, semi-classical, black hole is analyzed to provide evidence for the extra dimensions in a curved brane-world. It is argued that the gauge nonlinearity in the theory may be redefined by a potential in a moduli space. As a result, D = 11 and D = 12 dimensional geometries may be obtained at the stable extrema of the potential.

  13. The emergence of superconducting systems in Anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Wu, W. M.; Pierpoint, M. P.; Forrester, D. M.; Kusmartsev, F. V.

    2016-10-01

    In this article, we investigate the mathematical relationship between a (3+1) dimensional gravity model inside Anti-de Sitter space AdS4, and a (2+1) dimensional superconducting system on the asymptotically flat boundary of AdS4 (in the absence of gravity). We consider a simple case of the Type II superconducting model (in terms of Ginzburg-Landau theory) with an external perpendicular magnetic field H. An interaction potential V ( r, ψ) = α( T)| ψ|2 /r 2 + χ| ψ|2 /L 2 + β| ψ|4 /(2 r k ) is introduced within the Lagrangian system. This provides more flexibility within the model, when the superconducting system is close to the transition temperature T c. Overall, our result demonstrates that the Ginzburg-Landau differential equations can be directly deduced from Einstein's theory of general relativity.

  14. Conserved charges for gravity with locally anti-de sitter asymptotics

    PubMed

    Aros; Contreras; Olea; Troncoso; Zanelli

    2000-02-21

    A new formula for the conserved charges in 3+1 gravity for spacetimes with local anti-de Sitter asymptotic geometry is proposed. It is shown that requiring the action to have an extremum for this class of asymptotia sets the boundary term that must be added to the Lagrangian as the Euler density with a fixed weight factor. The resulting action gives rise to the mass and angular momentum as Noether charges associated to the asymptotic Killing vectors without requiring specification of a reference background in order to have a convergent expression. A consequence of this definition is that any negative constant curvature spacetime has vanishing Noether charges. These results remain valid in the Lambda = 0 limit.

  15. Charged anti-de Sitter scalar-tensor black holes and their thermodynamic phase structure

    SciTech Connect

    Doneva, Daniela D.; Yazadjiev, Stoytcho S.; Kokkotas, Kostas D.; Stefanov, Ivan Zh.; Todorov, Michail D.

    2010-05-15

    In the present paper we numerically construct new charged anti-de Sitter black holes coupled to nonlinear Born-Infeld electrodynamics within a certain class of scalar-tensor theories. The properties of the solutions are investigated both numerically and analytically. We also study the thermodynamics of the black holes in the canonical ensemble. For large values of the Born-Infeld parameter and for a certain interval of the charge values we find the existence of a first-order phase transition between small and very large black holes. An unexpected result is that for a certain small charge subinterval two phase transitions have been observed, one of zeroth and one of first order. It is important to note that such phase transitions are also observed for pure Einstein-Born-Infeld-AdS black holes.

  16. Holographic thermalization, stability of anti-de sitter space, and the Fermi-Pasta-Ulam paradox.

    PubMed

    Balasubramanian, Venkat; Buchel, Alex; Green, Stephen R; Lehner, Luis; Liebling, Steven L

    2014-08-15

    For a real massless scalar field in general relativity with a negative cosmological constant, we uncover a large class of spherically symmetric initial conditions that are close to anti-de Sitter space (AdS) but whose numerical evolution does not result in black hole formation. According to the AdS/conformal field theory (CFT) dictionary, these bulk solutions are dual to states of a strongly interacting boundary CFT that fail to thermalize at late times. Furthermore, as these states are not stationary, they define dynamical CFT configurations that do not equilibrate. We develop a two-time-scale perturbative formalism that captures both direct and inverse cascades of energy and agrees with our fully nonlinear evolutions in the appropriate regime. We also show that this formalism admits a large class of quasiperiodic solutions. Finally, we demonstrate a striking parallel between the dynamics of AdS and the classic Fermi-Pasta-Ulam-Tsingou problem.

  17. Holographic Thermalization, Stability of Anti-de Sitter Space, and the Fermi-Pasta-Ulam Paradox

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Venkat; Buchel, Alex; Green, Stephen R.; Lehner, Luis; Liebling, Steven L.

    2014-08-01

    For a real massless scalar field in general relativity with a negative cosmological constant, we uncover a large class of spherically symmetric initial conditions that are close to anti-de Sitter space (AdS) but whose numerical evolution does not result in black hole formation. According to the AdS/conformal field theory (CFT) dictionary, these bulk solutions are dual to states of a strongly interacting boundary CFT that fail to thermalize at late times. Furthermore, as these states are not stationary, they define dynamical CFT configurations that do not equilibrate. We develop a two-time-scale perturbative formalism that captures both direct and inverse cascades of energy and agrees with our fully nonlinear evolutions in the appropriate regime. We also show that this formalism admits a large class of quasiperiodic solutions. Finally, we demonstrate a striking parallel between the dynamics of AdS and the classic Fermi-Pasta-Ulam-Tsingou problem.

  18. New Dynamics in the Anti-de Sitter Universe AdS 5

    NASA Astrophysics Data System (ADS)

    Bachelot, Alain

    2013-06-01

    This paper deals with the propagation of the gravitational waves in the Poincaré patch of the 5-dimensional Anti-de Sitter universe. We construct a large family of unitary dynamics with respect to some high order energies that are conserved and positive. These dynamics are associated with asymptotic conditions on the conformal time-like boundary of the universe. This result does not contradict the statement of Breitenlohner-Freedman that the hamiltonian is essentially self-adjoint in L 2 and thus accordingly the dynamics is uniquely determined. The key point is the introduction of a new Hilbert functional framework that contains the massless graviton which is not normalizable in L 2. Then the hamiltonian is not essentially self-adjoint in this new space and possesses a lot of different positive self-adjoint extensions. These dynamics satisfy a holographic principle: there exists a renormalized boundary value which completely characterizes the whole field in the bulk.

  19. A scalar field condensation instability of rotating Anti-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Dias, Óscar J. C.; Monteiro, Ricardo; Reall, Harvey S.; Santos, Jorge E.

    2010-11-01

    Near-extreme Reissner-Nordström-anti-de Sitter black holes are unstable against the condensation of an uncharged scalar field with mass close to the Breitenlöhner-Freedman bound. It is shown that a similar instability afflicts near-extreme large rotating AdS black holes, and near-extreme hyperbolic Schwarzschild-AdS black holes. The resulting nonlinear hairy black hole solutions are determined numerically. Some stability results for (possibly charged) scalar fields in black hole backgrounds are proved. For most of the extreme black holes we consider, these demonstrate stability if the “effective mass” respects the near-horizon BF bound. Small spherical Reissner-Nordström-AdS black holes are an interesting exception to this result.

  20. Spinning σ-model solitons in 2 + 1 anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Harms, B.; Stern, A.

    2016-12-01

    We obtain numerical solutions for rotating topological solitons of the nonlinear σ-model in three-dimensional anti-de Sitter space. Two types of solutions, i) and ii), are found. The σ-model fields are everywhere well defined for both types of solutions, but they differ in their space-time domains. Any time slice of the space-time for the type i) solution has a causal singularity, despite the fact that all scalars constructed from the curvature tensor are bounded functions. No evidence of a horizon is seen for any of the solutions, and therefore the type i) solutions have naked singularities. On the other hand, the space-time domain, along with the fields, for the type ii) solutions are singularity free. Multiple families of solutions exhibiting bifurcation phenomena are found for this case.

  1. Strings in five-dimensional anti-de Sitter space with a symmetry

    SciTech Connect

    Koike, Tatsuhiko; Kozaki, Hiroshi; Ishihara, Hideki

    2008-06-15

    The equation of motion of an extended object in spacetime reduces to an ordinary differential equation in the presence of symmetry. By properly defining the symmetry with the notion of cohomogeneity, we discuss the method for classifying all these extended objects. We carry out the classification for the strings in the five-dimensional anti-de Sitter space by the effective use of the local isomorphism between SO(4,2) and SU(2,2). In the case where the string is described by the Nambu-Goto action, we present a general method for solving the trajectory. We then apply the method to one of the classification cases, where the spacetime naturally obtains a Hopf-like bundle structure, and find a solution. The geometry of the solution is analyzed and found to be a timelike, helicoidlike surface.

  2. Quantum groups, roots of unity and particles on quantized Anti-de Sitter space

    SciTech Connect

    Steinacker, Harold

    1997-05-23

    Quantum groups in general and the quantum Anti-de Sitter group Uq(so(2,3)) in particular are studied from the point of view of quantum field theory. The author shows that if q is a suitable root of unity, there exist finite-dimensional, unitary representations corresponding to essentially all the classical one-particle representations with (half) integer spin, with the same structure at low energies as in the classical case. In the massless case for spin ≥ 1, "naive" representations are unitarizable only after factoring out a subspace of "pure gauges", as classically. Unitary many-particle representations are defined, with the correct classical limit. Furthermore, the author identifies a remarkable element Q in the center of Uq(g), which plays the role of a BRST operator in the case of Uq(so(2,3)) at roots of unity, for any spin ≥ 1. The associated ghosts are an intrinsic part of the indecomposable representations. The author shows how to define an involution on algebras of creation and anihilation operators at roots of unity, in an example corresponding to non-identical particles. It is shown how nonabelian gauge fields appear naturally in this framework, without having to define connections on fiber bundles. Integration on Quantum Euclidean space and sphere and on Anti-de Sitter space is studied as well. The author gives a conjecture how Q can be used in general to analyze the structure of indecomposable representations, and to define a new, completely reducible associative (tensor) product of representations at roots of unity, which generalizes the standard "truncated" tensor product as well as many-particle representations.

  3. Vacuum for a massless quantum scalar field outside a collapsing shell in anti-de Sitter space-time

    NASA Astrophysics Data System (ADS)

    Abel, Paul G.; Winstanley, Elizabeth

    2016-08-01

    We consider a massless quantum scalar field on a two-dimensional space-time describing a thin shell of matter collapsing to form a Schwarzschild-anti-de Sitter black hole. At early times, before the shell starts to collapse, the quantum field is in the vacuum state, corresponding to the Boulware vacuum on an eternal black hole space-time. The scalar field satisfies reflecting boundary conditions on the anti-de Sitter boundary. Using the Davies-Fulling-Unruh prescription for computing the renormalized expectation value of the stress-energy tensor, we find that at late times the black hole is in thermal equilibrium with a heat bath at the Hawking temperature, so the quantum field is in a state analogous to the Hartle-Hawking vacuum on an eternal black hole space-time.

  4. 6D Anti-de Sitter Space Solutions to Einstein’s Field Equation with a Scalar Field

    DTIC Science & Technology

    2007-05-04

    Resource, http://mathworld.wolfram.com/RiemmannTensor.html. [7] F. Kristiansson, ”An Excusion into the Anti-de Sitter Spacetime and the World of...and Spacetime . (W.W. Norton & Co., New York, New York, 1976). [14] B. Grinstein, D. Nolte, and W. Skiba, ”On a Covariant Determination of Mass Scales in Warped Backgrounds,” Phys.Rev. 63, (2001).

  5. Thermodynamics of the Maxwell-Gauss-Bonnet anti-de Sitter black hole with higher derivative gauge corrections

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; Pastras, Georgios

    2009-07-01

    The local and global thermal phase structure for asymptotically anti-de Sitter black holes charged under an abelian gauge group, with both Gauss-Bonnet and quartic field strength corrections, is mapped out for all parameter space. We work in the grand canonical ensemble where the external electric potential is held fixed. The analysis is performed in an arbitrary number of dimensions, for all three possible horizon topologies — spherical, flat or hyperbolic. For spherical horizons, new metastable configurations are exhibited both for the pure Gauss-Bonnet theory as well as the pure higher derivative gauge theory and combinations thereof. In the pure Gauss-Bonnet theory with negative coefficient and five or more spatial dimensions, two locally thermally stable black hole solutions are found for a given temperature. Either one or both of them may be thermally favored over the anti-de Sitter vacuum — corresponding to a single or a double decay channel for the metastable black hole. Similar metastable configurations are uncovered for the theory with pure quartic field strength corrections, as well combinations of the two types of corrections, in three or more spatial dimensions. Finally, a secondary Hawking-Page transition between the smaller thermally favored black hole and thermal anti-de Sitter space is observed when both corrections are turned on and their couplings are both positive.

  6. The Wave Turbulence Approach to Gravitational Collapse in Anti-de Sitter Space

    NASA Astrophysics Data System (ADS)

    Cook, Brian; Pando Zayas, Leopoldo

    2017-01-01

    Over the last few decades there has been a great deal of research relating gravity to the dynamics of fluids. In the weakly turbulent regime fluids can be described using the formulation of wave turbulence rather than full-blown Kolmogorov turbulence, which uses vortices. It is with these two ideas in mind that we construct the wave equation describing gravitational collapse of a scalar field in anti de-Sitter (AdS) space using Einstein's field equations. By using the appropriate limits we reach a solution with truncated terms for increasingly complicated mode interactions. While this formulation has implications in the AdS/CFT correspondence we are more concerned with the implications of this wave turbulence formulation as it relates to gravitational waves in asymptotically flat space. When there is negligible interaction between modes the wave acts as a simple harmonic oscillator, but for nonlinear time scales ($\\sim 1/A^{2}$) the interactions become important and we simulate the cascade from one mode of the wave to the next using numerical techniques. Future research will be focused on geometrodynamics as it relates to compact objects and the analysis of data being generated by gravitational wave interferometers.

  7. Scalar hair on the black hole in asymptotically anti--de Sitter spacetime

    SciTech Connect

    Torii, Takashi; Maeda, Kengo; Narita, Makoto

    2001-08-15

    We examine the no-hair conjecture in asymptotically anti--de Sitter (AdS) spacetime. First, we consider a real scalar field as the matter field and assume static spherically symmetric spacetime. Analysis of the asymptotics shows that the scalar field must approach the extremum of its potential. Using this fact, it is proved that there is no regular black hole solution when the scalar field is massless or has a 'convex' potential. Surprisingly, while the scalar field has a growing mode around the local minimum of the potential, there is no growing mode around the local maximum. This implies that the local maximum is a kind of 'attractor' of the asymptotic scalar field. We give two examples of the new black hole solutions with a nontrivial scalar field configuration numerically in the symmetric or asymmetric double well potential models. We study the stability of these solutions by using the linear perturbation method in order to examine whether or not the scalar hair is physical. In the symmetric double well potential model, we find that the potential function of the perturbation equation is positive semidefinite in some wide parameter range and that the new solution is stable. This implies that the black hole no-hair conjecture is violated in asymptotically AdS spacetime.

  8. Rainbow valley of colored (anti) de Sitter gravity in three dimensions

    NASA Astrophysics Data System (ADS)

    Gwak, Seungho; Joung, Euihun; Mkrtchyan, Karapet; Rey, Soo-Jong

    2016-04-01

    We propose a theory of three-dimensional (anti) de Sitter gravity carrying Chan-Paton color charges. We define the theory by Chern-Simons formulation with the gauge algebra (gl_2oplus gl_2)⊗ u(N) , obtaining a color-decorated version of interacting spin-one and spin-two fields. We also describe the theory in metric formulation and show that, among N 2 massless spin-two fields, only the singlet one plays the role of metric graviton whereas the rest behave as colored spinning matter that strongly interacts at large N. Remarkably, these colored spinning matter acts as Higgs field and generates a non-trivial potential of staircase shape. At each extremum labelled by k=0,dots, [N-1/2] , the u(N) color gauge symmetry is spontaneously broken down to u(N-k)oplus u(k) and provides different (A)dS backgrounds with the cosmological constants {(N/N-2k)}^2Λ . When this symmetry breaking takes place, the spin-two Goldstone modes combine with (or are eaten by) the spin-one gauge fields to become partially-massless spin-two fields. We discuss various aspects of this theory and highlight physical implications.

  9. Reissner-Nordstrom-anti-de Sitter nontopological solitons in broken Einstein-Maxwell-Higgs theory

    NASA Astrophysics Data System (ADS)

    Honda, Ethan

    2017-01-01

    Results are presented from numerical simulations of the Einstein-Maxwell-Higgs equations with a broken U(1) symmetry. Coherent nontopological soliton solutions are shown to exist that separate an anti-de Sitter (AdS) true vacuum interior from a Reissner-Nordstrom (RN) false vacuum exterior. The stability of these bubble solutions is tested by perturbing the charge of the coherent solution and evolving the time-dependent equations of motion. In the weak gravitational limit, the short-term stability depends on the sign of (ω /Q )∂ωQ , similar to Q -balls. The long-term end state of the perturbed solutions demonstrates a rich structure and is visualized using "phase diagrams." Regions of both stability and instability are shown to exist for κg≲0.015 , while solutions with κg≳0.015 were observed to be entirely unstable. Threshold solutions are shown to demonstrate time-scaling laws, and the space separating true and false vacuum end states is shown to be fractal in nature, similar to oscillons. Coherent states with superextremal charge-to-mass ratios are shown to exist and observed to collapse or expand, depending on the sign of the charge perturbation. Expanding superextremal bubbles induce phase transitions to the true AdS vacuum, while collapsing superextremal bubbles can form nonsingular strongly gravitating solutions with superextremal RN exteriors.

  10. Thin-shell bubbles and information loss problem in anti de Sitter background

    NASA Astrophysics Data System (ADS)

    Sasaki, Misao; Yeom, Dong-han

    2014-12-01

    We study the motion of thin-shell bubbles and their tunneling in anti de Sitter (AdS) background. We are interested in the case when the outside of a shell is a Schwarzschild-AdS space (false vacuum) and the inside of it is an AdS space with a lower vacuum energy (true vacuum). If a collapsing true vacuum bubble is created, classically it will form a Schwarzschild-AdS black hole. However, this collapsing bubble can tunnel to a bouncing bubble that moves out to spatial infinity. Then, although the classical causal structure of a collapsing true vacuum bubble has the singularity and the event horizon, quantum mechanically the wavefunction has support for a history without any singularity nor event horizon which is mediated by the non-perturbative, quantum tunneling effect. This may be regarded an explicit example that shows the unitarity of an asymptotic observer in AdS, while a classical observer who only follows the most probable history effectively lose information due to the formation of an event horizon.

  11. More on asymptotically anti-de Sitter spaces in topologically massive gravity

    SciTech Connect

    Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo

    2010-09-15

    Recently, the asymptotic behavior of three-dimensional anti-de Sitter (AdS) gravity with a topological mass term was investigated. Boundary conditions were given that were asymptotically invariant under the two dimensional conformal group and that included a falloff of the metric sufficiently slow to consistently allow pp-wave type of solutions. Now, pp waves can have two different chiralities. Above the chiral point and at the chiral point, however, only one chirality can be considered, namely, the chirality that has the milder behavior at infinity. The other chirality blows up faster than AdS and does not define an asymptotically AdS spacetime. By contrast, both chiralities are subdominant with respect to the asymptotic behavior of AdS spacetime below the chiral point. Nevertheless, the boundary conditions given in the earlier treatment only included one of the two chiralities (which could be either one) at a time. We investigate in this paper whether one can generalize these boundary conditions in order to consider simultaneously both chiralities below the chiral point. We show that this is not possible if one wants to keep the two-dimensional conformal group as asymptotic symmetry group. Hence, the boundary conditions given in the earlier treatment appear to be the best possible ones compatible with conformal symmetry. In the course of our investigations, we provide general formulas controlling the asymptotic charges for all values of the topological mass (not just below the chiral point).

  12. Globally regular instability of 3-dimensional anti-de Sitter spacetime.

    PubMed

    Bizoń, Piotr; Jałmużna, Joanna

    2013-07-26

    We consider three-dimensional anti-de Sitter (AdS) gravity minimally coupled to a massless scalar field and study numerically the evolution of small smooth circularly symmetric perturbations of the AdS3 spacetime. As in higher dimensions, for a large class of perturbations, we observe a turbulent cascade of energy to high frequencies which entails instability of AdS3. However, in contrast to higher dimensions, the cascade cannot be terminated by black hole formation because small perturbations have energy below the black hole threshold. This situation appears to be challenging for the cosmic censor. Analyzing the energy spectrum of the cascade we determine the width ρ(t) of the analyticity strip of solutions in the complex spatial plane and argue by extrapolation that ρ(t) does not vanish in finite time. This provides evidence that the turbulence is too weak to produce a naked singularity and the solutions remain globally regular in time, in accordance with the cosmic censorship hypothesis.

  13. On quantum deformations of (anti-)de Sitter algebras in (2+1) dimensions

    NASA Astrophysics Data System (ADS)

    Ballesteros, A.; Herranz, F. J.; Musso, F.

    2014-09-01

    Quantum deformations of (anti-)de Sitter (A)dS algebras in (2+1) dimensions are revisited, and several features of these quantum structures are reviewed. In particular, the classification problem of (2+1) (A)dS Lie bialgebras is presented and the associated noncommutative quantum (A)dS spaces are also analysed. Moreover, the flat limit (or vanishing cosmological constant) of all these structures leading to (2+1) quantum Poincare algebras and groups is simultaneously given by considering the cosmological constant as an explicit Lie algebra parameter in the (A)dS algebras. By making use of this classification, a three-parameter generalization of the K-deformation for the (2+1) (A)dS algebras and quantum spacetimes is given. Finally, the same problem is studied in (3+1) dimensions, where a two-parameter generalization of the κ-(A)dS deformation that preserves the space isotropy is found.

  14. Black hole formation from pointlike particles in three-dimensional anti-de Sitter space

    NASA Astrophysics Data System (ADS)

    Lindgren, E. J.

    2016-07-01

    We study collisions of many point-like particles in three-dimensional anti-de Sitter space, generalizing the known result with two particles. We show how to construct exact solutions corresponding to the formation of either a black hole or a conical singularity from the collision of an arbitrary number of massless particles falling in radially from the boundary. We find that when going away from the case of equal energies and discrete rotational symmetry, this is not a trivial generalization of the two-particle case, but requires that the excised wedges corresponding to the particles must be chosen in a very precise way for a consistent solution. We also explicitly take the limit when the number of particles goes to infinity and obtain thin shell solutions that in general break rotational invariance, corresponding to an instantaneous and inhomogeneous perturbation at the boundary. We also compute the stress-energy tensor of the shell using the junction formalism for null shells and obtain agreement with the point particle picture.

  15. Instantons near a tachyonic top in an anti de Sitter and the no-boundary regulator

    NASA Astrophysics Data System (ADS)

    Lee, Bum-Hoon; Lee, Wonwoo; Ro, Daeho; Yeom, Dong-han

    2015-08-01

    We investigate instantons near a tachyonic top in an anti de Sitter (AdS) background. If the mass scale around the hill-top is above the Breitenlohner-Freedman (BF) bound, then the top is classically stable. When the BF bound is satisfied, it is already known that there can exist instantons with a non-zero probability, though fine-tunings of the potential are required. On the other hand, we may consider a possibility to obtain instantons with a non-zero probability for a more natural shape of potentials. We found that the no-boundary regulator is useful to assign a non-zero probability for general instantons near the tachyonic top with a consistent framework. To use the no-boundary regulator, we need to introduce the complexification of fields. One interesting feature is that, for these AdS instantons, the classicality may not be satisfied after the Wick rotation and hence after the nucleation. This magnifies a novel difference between dS and AdS; a semi-classical boundary observer in AdS may notice the dispersion of quantum fields as a kind of uncertainty, while every semi-classical observer in dS is classicalized individually and hence there is no semi-classical observer who can see the quantum dispersion of the scalar field.

  16. Randall-Sundrum membrane model with 7D anti-de Sitter space

    SciTech Connect

    Bao, Ruoyu; Lykken, Joseph D.; /Chicago U., EFI /Chicago U. /Fermilab

    2005-09-01

    In the same sense that AdS{sub 5} warped geometries arise naturally from Type IIB string theory with stacks of D3 branes, AdS{sub 7} warped geometries arise naturally from M theory with stacks of M5 branes. We compactify two spatial dimensions of AdS{sub 7} to get AdS{sub 5} x {Sigma}{sup 2}, where {Sigma}{sup 2} is e.g. a torus T{sup 2} or a sphere S{sup 2}. The metric for {Sigma} inherits the same warp factor as appears in the AdS{sub 5}. Bulk fields generically have both Kaluza-Klein and winding modes associated with {Sigma}. In the effective 5d action these will contribute exotic new excitations. We analyze the 5d spectrum in detail for the case of a bulk scalar or a graviton in AdS{sub 5} x T{sup 2}, in a setup which mimics the first Randall-Sundrum model. The results display several novel features, some of which might be observed in experiments at the LHC. For example, we obtain TeV scale string winding states without lowering the string scale. This is due to the double warping which is a generic feature of winding states along compactified AdS directions. Experimental verification of these signatures of AdS{sub 7} could be interpreted as direct evidence for M theory.

  17. Final fate of instability of Reissner-Nordstroem-anti-de Sitter black holes by charged complex scalar fields

    SciTech Connect

    Maeda, Kengo; Fujii, Shunsuke; Koga, Jun-ichirou

    2010-06-15

    We investigate instability of four-dimensional Reissner-Nordstroem-anti-de Sitter (RN-AdS{sub 4}) black holes with various topologies by charged scalar field perturbations. We numerically find that the RN-AdS{sub 4} black holes become unstable against the linear perturbations below a critical temperature. It is analytically shown that charge extraction from the black holes occurs during the unstable evolution. To explore the end state of the instability, we perturbatively construct static black hole solutions with the scalar hair near the critical temperature. It is numerically found that the entropy of the hairy black hole is always larger than the one of the unstable RN-AdS{sub 4} black hole in the microcanonical ensemble. Our results support the speculation that the black hole with charged scalar hair always appears as the final fate of the instability of the RN-AdS{sub 4} black hole.

  18. Fermion tunnels of higher-dimensional anti-de Sitter Schwarzschild black hole and its corrected entropy

    NASA Astrophysics Data System (ADS)

    Lin, Kai; Yang, ShuZheng

    2009-10-01

    Applying the method beyond semiclassical approximation, fermion tunneling from higher-dimensional anti-de Sitter Schwarzschild black hole is researched. In our work, the "tortoise" coordinate transformation is introduced to simplify Dirac equation, so that the equation proves that only the (r - t) sector is important to our research. Because we only need to study the (r - t) sector, the Dirac equation is decomposed into several pairs of equations spontaneously, and we then prove the components of wave functions are proportional to each other in every pair of equations. Therefore, the suitable action forms of the wave functions are obtained, and finally the correctional Hawking temperature and entropy can be determined via the method beyond semiclassical approximation.

  19. Test of the Anti-de Sitter-Space/Conformal-Field-Theory Correspondence Using High-Spin Operators

    SciTech Connect

    Benna, M. K.; Benvenuti, S.; Klebanov, I. R.; Scardicchio, A.

    2007-03-30

    In two remarkable recent papers the planar perturbative expansion was proposed for the universal function of the coupling appearing in the dimensions of high-spin operators of the N=4 super Yang-Mills theory. We study numerically the integral equation derived by Beisert, Eden, and Staudacher, which resums the perturbative series. In a confirmation of the anti-de Sitter-space/conformal-field-theory (AdS/CFT) correspondence, we find a smooth function whose two leading terms at strong coupling match the results obtained for the semiclassical folded string spinning in AdS{sub 5}. We also make a numerical prediction for the third term in the strong coupling series.

  20. Quasinormal modes and thermodynamics of linearly charged BTZ black holes in massive gravity in (anti) de Sitter space-time

    NASA Astrophysics Data System (ADS)

    Prasia, P.; Kuriakose, V. C.

    2017-01-01

    In this work we study the Quasi-Normal Modes (QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter ((A)dS) space-time. It is found that the behavior of QNMs changes with the massive parameter of the graviton and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space-time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter of the graviton and also on the charge of the black hole.

  1. Characteristics of transonic spherical symmetric accretion flow in Schwarzschild-de Sitter and Schwarzschild anti-de Sitter backgrounds, in pseudo-general relativistic paradigm

    NASA Astrophysics Data System (ADS)

    Ghosh, Shubhrangshu; Banik, Prabir

    2015-07-01

    In this paper, we present a complete work on steady state spherically symmetric Bondi type accretion flow in the presence of cosmological constant (Λ) in both Schwarzschild-de Sitter (SDS) and Schwarzschild anti-de Sitter (SADS) backgrounds considering an isolated supermassive black hole (SMBH), with the inclusion of a simple radiative transfer scheme, in the pseudo-general relativistic paradigm. We do an extensive analysis on the transonic behavior of the Bondi type accretion flow onto the cosmological BHs including a complete analysis of the global parameter space and the stability of flow, and do a complete study of the global family of solutions for a generic polytropic flow. Bondi type accretion flow in SADS background renders multiplicity in its transonic behavior with inner "saddle" type and outer "center" type sonic points, with the transonic solutions forming closed loops or contours. There is always a limiting value for ∣Λ∣ up to which we obtain valid stationary transonic solutions, which correspond to both SDS and SADS geometries; this limiting value moderately increases with the increasing radiative efficiency of the flow, especially correspond to Bondi type accretion flow in SADS background. Repulsive Λ suppresses the Bondi accretion rate by an order of magnitude for relativistic Bondi type accretion flow for a certain range in temperature, and with a marginal increase in the Bondi accretion rate if the corresponding accretion flow occurs in SADS background. However, for a strongly radiative Bondi type accretion flow with high mass accretion rate, the presence of cosmological constant do not much influence the corresponding Bondi accretion rate of the flow. Our analysis show that the relic cosmological constant has a substantial effect on Bondi type accretion flow onto isolated SMBHs and their transonic solutions beyond length-scale of kiloparsecs, especially if the Bondi type accretion occurs onto the host supergiant ellipticals or central

  2. Stability of Gauss-Bonnet black holes in anti-de Sitter space-time against scalar field condensation

    SciTech Connect

    Brihaye, Yves; Hartmann, Betti

    2011-10-15

    We study the stability of static, hyperbolic Gauss-Bonnet black holes in (4+1)-dimensional anti-de Sitter (AdS) space-time against the formation of scalar hair. Close to extremality the black holes possess a near-horizon topology of AdS{sub 2}xH{sup 3} such that within a certain range of the scalar field mass one would expect that they become unstable to the condensation of an uncharged scalar field. We confirm this numerically and observe that there exists a family of hairy black hole solutions labeled by the number of nodes of the scalar field function. We construct explicit examples of solutions with a scalar field that possesses zero nodes, one node, and two nodes, respectively, and show that the solutions with nodes persist in the limit of Einstein gravity, i.e. for vanishing Gauss-Bonnet coupling. We observe that the interval of the mass for which scalar field condensation appears decreases with increasing Gauss-Bonnet coupling and/or with increasing node number.

  3. Phase structure of the Born-Infeld-anti-de Sitter black holes probed by non-local observables

    NASA Astrophysics Data System (ADS)

    Zeng, Xiao-Xiong; Liu, Xian-Ming; Li, Li-Fang

    2016-11-01

    With the non-local observables such as two point correlation function and holographic entanglement entropy, we probe the phase structure of the Born-Infeld-anti-de Sitter black holes. For the case bQ>0.5, where b is the Born-Infeld parameter and Q is the charge of the black hole, the phase structure is found to be similar to that of the Van der Waals phase transition, namely the black hole undergoes a first order phase transition and a second order phase transition before it reaches a stable phase. While for the case bQ<0.5, a new phase branch emerges besides the Van der Waals phase transition. For the first order phase transition, the equal area law is checked, and for the second order phase transition, the critical exponent of the heat capacity is obtained. All these results are found to be the same as that observed in the entropy-temperature plane.

  4. Dyons and dyonic black holes in su (N ) Einstein-Yang-Mills theory in anti-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Shepherd, Ben L.; Winstanley, Elizabeth

    2016-03-01

    We present new spherically symmetric, dyonic soliton and black hole solutions of the su (N ) Einstein-Yang-Mills equations in four-dimensional asymptotically anti-de Sitter spacetime. The gauge field has nontrivial electric and magnetic components and is described by N -1 magnetic gauge field functions and N -1 electric gauge field functions. We explore the phase space of solutions in detail for su (2 ) and su (3 ) gauge groups. Combinations of the electric gauge field functions are monotonic and have no zeros; in general the magnetic gauge field functions may have zeros. The phase space of solutions is extremely rich, and we find solutions in which the magnetic gauge field functions have more than fifty zeros. Of particular interest are solutions for which the magnetic gauge field functions have no zeros, which exist when the negative cosmological constant has sufficiently large magnitude. We conjecture that at least some of these nodeless solutions may be stable under linear, spherically symmetric, perturbations.

  5. Maxwell perturbations on asymptotically anti-de Sitter spacetimes: Generic boundary conditions and a new branch of quasinormal modes

    NASA Astrophysics Data System (ADS)

    Wang, Mengjie; Herdeiro, Carlos; Sampaio, Marco O. P.

    2015-12-01

    Perturbations of asymptotically anti-de-Sitter (AdS) spacetimes are often considered by imposing field vanishing boundary conditions (BCs) at the AdS boundary. Such BCs, of Dirichlet-type, imply a vanishing energy flux at the boundary, but the converse is, generically, not true. Regarding AdS as a gravitational box, we consider vanishing energy flux (VEF) BCs as a more fundamental physical requirement and we show that these BCs can lead to a new branch of modes. As a concrete example, we consider Maxwell perturbations on Kerr-AdS black holes in the Teukolsky formalism, but our formulation applies also for other spin fields. Imposing VEF BCs, we find a set of two Robin BCs, even for Schwarzschild-AdS black holes. The Robin BCs on the Teukolsky variables can be used to study quasinormal modes, superradiant instabilities and vector clouds. As a first application, we consider here the quasinormal modes of Schwarzschild-AdS black holes. We find that one of the Robin BCs yields the quasinormal spectrum reported in the literature, while the other one unveils a new branch for the quasinormal spectrum.

  6. The Klein-Gordon-Fock equation in the curved spacetime of the Kerr-Newman (anti) de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Kraniotis, G. V.

    2016-11-01

    Exact solutions of the Klein-Gordon-Fock (KGF) general relativistic equation that describe the dynamics of a massive, electrically charged scalar particle in the curved spacetime geometry of an electrically charged, rotating Kerr-Newman-(anti) de Sitter black hole are investigated. In the general case of a rotating, charged, cosmological black hole the solution of the KGF equation with the method of separation of variables results in Fuchsian differential equations for the radial and angular parts which for most of the parameter space contain more than three finite singularities and thereby generalise the Heun differential equations. For particular values of the physical parameters (i.e. mass of the scalar particle) these Fuchsian equations reduce to the case of the Heun equation and the closed form analytic solutions we derive are expressed in terms of Heun functions. For other values of the parameters some of the extra singular points are false singular points. We derive the conditions on the coefficients of the generalised Fuchsian equation such that a singular point is a false point. In such a case the exact solution of the Fuchsian equation can in principle be simplified and expressed in terms of Heun functions. This is the generalisation of the case of a Heun equation with a false singular point in which the exact solution of Heun’s differential equation is expressed in terms of Gauß hypergeometric function. We also derive the exact solutions of the radial and angular equations for a charged massive scalar particle in the Kerr-Newman spacetime. The analytic solutions are expressed in terms of confluent Heun functions. Moreover, we derived the constraints on the parameters of the theory such that the solution simplifies and expressed in terms of confluent Kummer hypergeometric functions. We also investigate the radial solutions in the KN case in the regions near the event horizon and far from the black hole. Finally, we construct several expansions of the

  7. On the global existence of hairy black holes and solitons in anti-de Sitter Einstein-Yang-Mills theories with compact semisimple gauge groups

    NASA Astrophysics Data System (ADS)

    Baxter, J. Erik

    2016-10-01

    We investigate the existence of black hole and soliton solutions to four dimensional, anti-de Sitter (adS), Einstein-Yang-Mills theories with general semisimple connected and simply connected gauge groups, concentrating on the so-called regular case. We here generalise results for the asymptotically flat case, and compare our system with similar results from the well-researched adS {mathfrak {su}}(N) system. We find the analysis differs from the asymptotically flat case in some important ways: the biggest difference is that for Λ <0, solutions are much less constrained as r→ infty , making it possible to prove the existence of global solutions to the field equations in some neighbourhood of existing trivial solutions, and in the limit of |Λ |→ infty . In particular, we can identify non-trivial solutions where the gauge field functions have no zeroes, which in the {mathfrak {su}}(N) case proved important to stability.

  8. Constraints on Meta-stable de Sitter Flux Vacua

    SciTech Connect

    Soroush, Masoud

    2007-03-05

    We consider flux compactification of type IIB string theory as the orientifold limit of an F-theory on a Calabi-Yau fourfold. We show that when supersymmetry is dominantly broken by the axion-dilaton and the contributions of the F-terms associated with complex structure moduli are small, the Hessian of the flux potential always has tachyonic modes for de Sitter vacua. This implies that there exist no meta-stable de Sitter vacua in this limit. Moreover, we find that the stability requirement imposes a relation between the values of cosmological constant and the scale of supersymmetry breaking for non-supersymmetric anti de Sitter vacua in this limit. The proof is general and does rely on the details of the geometry of the compact Calabi-Yau internal space. We finally analyze the consequences of these constraints on the statistics of meta-stable de Sitter vacua and address some other related issues.

  9. Configurational entropy of anti-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Braga, Nelson R. F.; da Rocha, Roldão

    2017-04-01

    Recent studies indicate that the configurational entropy is an useful tool to investigate the stability and (or) the relative dominance of states for diverse physical systems. Recent examples comprise the connection between the variation of this quantity and the relative fraction of light mesons and glueballs observed in hadronic processes. Here we develop a technique for defining a configurational entropy for an AdS-Schwarzschild black hole. The achieved result corroborates consistency with the Hawking-Page phase transition. Namely, the dominance of the black hole configurational entropy will be shown to increase with the temperature. In order to verify the consistency of the new procedure developed here, we also consider the case of black holes in flat space-time. For such a black hole, it is known that evaporation leads to instability. The configurational entropy obtained for the flat space case is thoroughly consistent with the physical expectation. In fact, we show that the smaller the black holes, the more unstable they are. So, the configurational entropy furnishes a reliable measure for stability of black holes.

  10. Expanding plasmas from anti de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Camilo, Giancarlo

    2016-12-01

    We introduce a new foliation of AdS_5 black holes such that the conformal boundary takes the form of a 4-dimensional FLRW spacetime with scale factor a( t). The foliation employs Eddington-Finkelstein-like coordinates and is applicable to a large class of AdS black holes, supported by matter fields or not, considerably extending previous efforts in the literature. We argue that the holographic dual picture of a CFT plasma on a FLRW background provides an interesting prototype to study the nonequilibrium dynamics of expanding plasmas and use holographic renormalization to extract the renormalized energy-momentum tensor of the dual plasma. We illustrate the procedure for three black holes of interest, namely AdS-Schwarzschild, AdS-Gauss-Bonnet, and AdS-Reissner-Nordström. For the latter, as a by-product, we show that the nonequilibrium dynamics of a CFT plasma subject to a quench in the chemical potential (i.e., a time-dependent chemical potential) resembles a cosmological evolution with the scale factor a( t) being inversely related to the quench profile μ (t).

  11. Anti-de Sitter D-branes in curved backgrounds

    NASA Astrophysics Data System (ADS)

    Huang, Wung-Hong

    2005-07-01

    We investigate the properties of the AdS D1-branes which are the bound states of a curved D1-brane with n fundamental strings (F1) in the AdS3 spacetime, and the AdS D2-branes which are the axially symmetric bound states of a curved D2-brane with m D0-branes and n fundamental strings in the AdS3 × S3 spacetime. We see that, while the AdS D1-branes asymptotically approach to the event horizon of the AdS3 spacetime the AdS D2-branes will end on it. As the near horizon geometry of the F1/NS5 becomes the spacetime of AdS3 × S3 × T4 with NS-NS three form turned on, we furthermore investigate the corresponding AdS D-branes in the NS5-branes and macroscopic F-strings backgrounds, as an attempt to understand the origin of the AdS D-branes. From the found DBI solutions we see that in the F-strings background, both of the AdS D1-branes and AdS D2-branes will asymptotically approach to the position with a finite distance away from the F-strings. However, the AdS D2-branes therein could also end on the F-strings once it carries sufficient D0-branes charges. We also see that there does not exist any stable AdS D-branes in the NS5-branes backgrounds. We present physical arguments to explain these results, which could help us in understanding the intriguing mechanics of the formation of the AdS D-branes.

  12. Perturbations on and off de Sitter brane in anti-de Sitter bulk

    NASA Astrophysics Data System (ADS)

    Libanov, M.; Rubakov, V.

    2016-09-01

    Motivated by holographic models of a (pseudo)conformal Universe, we carry out a complete analysis of linearized metric perturbations in the time-dependent two-brane setup of the Lykken-Randall type. We present the equations of motion for the scalar, vector and tensor perturbations and identify light modes in the spectrum, which are scalar radion and transverse-traceless graviton. We show that there are no other modes in the discrete part of the spectrum. We pay special attention to properties of light modes and show, in particular, that the radion has red power spectrum at late times, as anticipated on holographic grounds. Unlike the graviton, the radion survives in the single-brane limit, when one of the branes is sent to the adS boundary. These properties imply that potentially observable features characteristic of the 4d (pseudo)conformal cosmology, such as statistical anisotropy and specific shapes of non-Gaussianity, are inherent also in holographic conformal models as well as in brane world inflation.

  13. 'Micromanaging de Sitter holography'

    SciTech Connect

    Dong, Xi; Horn, Bart; Silverstein, Eva; Torroba, Gonzalo; /SLAC /Stanford U., Phys. Dept. /Santa Barbara, KITP

    2010-08-26

    We develop tools to engineer de Sitter vacua with semi-holographic duals, using elliptic fibrations and orientifolds to uplift Freund-Rubin compactifications with CFT duals. The dual brane construction is compact and constitutes a microscopic realization of the dS/dS correspondence, realizing d-dimensional de Sitter space as a warped compactification down to (d-1)-dimensional de Sitter gravity coupled to a pair of large-N matter sectors. This provides a parametric microscopic interpretation of the Gibbons-Hawking entropy. We illustrate these ideas with an explicit class of examples in three dimensions, and describe ongoing work on four-dimensional constructions. The Gibbons-Hawking entropy of the de Sitter horizon [1] invites a microscopic interpretation and a holographic formulation of inflating spacetimes. Much progress was made in the analogous problem in black hole physics using special black holes in string theory whose microstates could be reliably counted, such as those analyzed in [2,3]; this led to the AdS/CFT correspondence [4]. In contrast, a microscopic understanding of the entropy of de Sitter space is more difficult for several reasons including its potential dynamical connections to other backgrounds (metastability), the absence of a non-fluctuating timelike boundary, and the absence of supersymmetry. In this paper, we develop a class of de Sitter constructions in string theory, built up from AdS/CFT dual pairs along the lines of [5], which are simple enough to provide a microscopic accounting of the parametric scaling of the Gibbons-Hawking entropy. These models realize microscopically a semi-holographic description of metastable de Sitter space which had been derived macroscopically in [6]. It would also be interesting to connect this to other approaches to de Sitter holography such as [7, 8] and to other manifestations of the de Sitter entropy such as [9]. The construction is somewhat analogous to neutral black branes analyzed in [11]. We will

  14. De Sitter vacua and N = 2 supergravity

    NASA Astrophysics Data System (ADS)

    Ogetbil, Orcan Bahri

    After reviewing the existing results we give an extensive analysis of the critical points of the potentials of the gauged N = 2 Yang-Mills/Einstein Supergravity theories coupled to tensor- and hyper multiplets in five dimensions. Our analysis includes all the possible gaugings of all N = 2 Maxwell-Einstein supergravity theories whose scalar manifolds are symmetric spaces. In general, the scalar potential gets contributions from R-symmetry gauging, tensor couplings and hyper-couplings. We show that the coupling of a hypermultiplet into a theory whose potential has a non-zero value at its critical point, and gauging a compact subgroup of the hyperscalar isometry group will only rescale the value of the potential at the critical point by a positive factor, and therefore will not change the nature of an existing critical point. However this is not the case for non-compact SO(1, 1) gaugings. An SO(1, 1) gauging of the hyper isometry will generally lead to de Sitter vacua, which is analogous to the ground states found by simultaneously gauging SO(1, 1) symmetry of the real scalar manifold of the five dimensional vector multiplets with U(1)R in earlier literature. SO(m, 1) gaugings with m > 1, which give contributions to the scalar potential only in the Magical Jordan family theories, on the other hand, do not lead to de Sitter vacua. Anti-de Sitter vacua are generically obtained when the U(1)R symmetry is gauged. We also show that it is possible to embed certain generic Jordan family theories into the Magical Jordan family while preserving the nature of the ground states. However the Magical Jordan family theories admit additional vacua which are not found in the generic Jordan family theories. The five dimensional stable de Sitter ground states obtained by gauging SO(1, 1) symmetry of the real symmetric scalar manifold (in particular a generic Jordan family manifold of the vector multiplets) simultaneously with a subgroup Rs of the R-symmetry group descend to four

  15. Simple de Sitter solutions

    SciTech Connect

    Silverstein, Eva

    2008-05-15

    We present a framework for de Sitter model building in type IIA string theory, illustrated with specific examples. We find metastable de Sitter (dS) minima of the potential for moduli obtained from a compactification on a product of two nil three-manifolds (which have negative scalar curvature) combined with orientifolds, branes, fractional Chern-Simons forms, and fluxes. As a discrete quantum number is taken large, the curvature, field strengths, inverse volume, and four-dimensional string coupling become parametrically small, and the de Sitter Hubble scale can be tuned parametrically smaller than the scales of the moduli, Kaluza Klein (KK), and winding mode masses. A subtle point in the construction is that although the curvature remains consistently weak, the circle fibers of the nilmanifolds become very small in this limit (though this is avoided in illustrative solutions at modest values of the parameters). In the simplest version of the construction, the heaviest moduli masses are parametrically of the same order as the lightest KK and winding masses. However, we provide a method for separating these marginally overlapping scales, and more generally the underlying supersymmetry of the model protects against large corrections to the low-energy moduli potential.

  16. Simple de Sitter Solutions

    SciTech Connect

    Silverstein, Eva; /Stanford U., Phys. Dept. /SLAC

    2008-01-07

    We present a framework for de Sitter model building in type IIA string theory, illustrated with specific examples. We find metastable dS minima of the potential for moduli obtained from a compactification on a product of two Nil three-manifolds (which have negative scalar curvature) combined with orientifolds, branes, fractional Chern-Simons forms, and fluxes. As a discrete quantum number is taken large, the curvature, field strengths, inverse volume, and four dimensional string coupling become parametrically small, and the de Sitter Hubble scale can be tuned parametrically smaller than the scales of the moduli, KK, and winding mode masses. A subtle point in the construction is that although the curvature remains consistently weak, the circle fibers of the nilmanifolds become very small in this limit (though this is avoided in illustrative solutions at modest values of the parameters). In the simplest version of the construction, the heaviest moduli masses are parametrically of the same order as the lightest KK and winding masses. However, we provide a method for separating these marginally overlapping scales, and more generally the underlying supersymmetry of the model protects against large corrections to the low-energy moduli potential.

  17. Nonstationary de Sitter Cosmological Models

    NASA Astrophysics Data System (ADS)

    Ibohal, Ng

    This paper proposes a class of nonstationary de Sitter, rotating and nonrotating, solutions to Einstein's field equations with a cosmological term of variable function Λ*(u). It is found that the space-time of the rotating nonstationary de Sitter model is algebraically special in the Petrov classification of the gravitational field with a null vector, which is a geodesic, shear-free, expanding as well as nonzero twist. However, that of the nonrotating nonstationary model is conformally flat, with nonempty space.

  18. Charlotte Moore Sitterly

    NASA Astrophysics Data System (ADS)

    Rubin, Vera C.

    2010-07-01

    Charlotte Moore Sitterly was a scientist in an era when it was rare for a woman to have the opportunity to devote her life to forefront science. Following her graduation from Swarthmore College in 1920, she accepted a position at Princeton University as an assistant to Henry Norris Russell. In 1925 she started a study of the solar spectrum. She could then not know that she would devote much of her scientific career to gathering basic atomic data that are invaluable to the scientific community, even today. In 1931 she obtained a Ph.D. degree at the University of California, Berkeley, and returned to Princeton as a staff member of the Princeton University Observatory. In 1945 Moore moved to the National Bureau of Standards (NBS), to supervise preparation of the widely-used tables of atomic energy levels. Following the successful launching (1946) of a V2 rocket to obtain the ultraviolet spectrum of the Sun, she started working also with Richard Tousey and his group at the Naval Research Laboratory (NRL). Ultimately, they extended the solar spectrum down to 2200 angstroms. She continued her affiliations with both the NBS and the NRL until her death in 1990. Charlotte Moore was a rare scientist who devoted her career to obtaining accurate numbers, thus enabling the scientific community to open her tables and know that the data are reliable.

  19. Analogue model for anti-de Sitter as a description of point sources in fluids

    NASA Astrophysics Data System (ADS)

    Mosna, Ricardo A.; Pitelli, João Paulo M.; Richartz, Maurício

    2016-11-01

    We introduce an analogue model for a nonglobally hyperbolic spacetime in terms of a two-dimensional fluid. This is done by considering the propagation of sound waves in a radial flow with constant velocity. We show that the equation of motion satisfied by sound waves is the wave equation on AdS2×S1. Since this spacetime is not globally hyperbolic, the dynamics of the Klein-Gordon field is not well defined until boundary conditions at the spatial boundary of AdS2 are prescribed. On the analogue model end, those extra boundary conditions provide an effective description of the point source at r =0 . For waves with circular symmetry, we relate the different physical evolutions to the phase difference between ingoing and outgoing scattered waves. We also show that the fluid configuration can be stable or unstable depending on the chosen boundary condition.

  20. Unstable Mode Solutions to the Klein-Gordon Equation in Kerr-anti-de Sitter Spacetimes

    NASA Astrophysics Data System (ADS)

    Dold, Dominic

    2017-03-01

    For any cosmological constant {Λ = -3/ℓ2 < 0} and any {α < 9/4}, we find a Kerr-AdS spacetime {({M}, g_{KAdS})}, in which the Klein-Gordon equation {Box_{g_{KAdS}}ψ + α/ℓ2ψ = 0} has an exponentially growing mode solution satisfying a Dirichlet boundary condition at infinity. The spacetime violates the Hawking-Reall bound {r+2 > |a|ℓ}. We obtain an analogous result for Neumann boundary conditions if {5/4 < α < 9/4}. Moreover, in the Dirichlet case, one can prove that, for any Kerr-AdS spacetime violating the Hawking-Reall bound, there exists an open family of masses {α} such that the corresponding Klein-Gordon equation permits exponentially growing mode solutions. Our result adopts methods of Shlapentokh-Rothman developed in (Commun. Math. Phys. 329:859-891, 2014) and provides the first rigorous construction of a superradiant instability for negative cosmological constant.

  1. Variations on holography from modifications of gravity in anti-de sitter

    NASA Astrophysics Data System (ADS)

    Apolo Velez, Luis Alberto

    In this thesis we study aspects of the AdS/CFT correspondence that result from modifications of gravity in the bulk and lead to novel features in the dual theories at the boundary. The variations on the holographic theme studied in this thesis are model-independent since we have not assumed a particular UV-completion of gravity. Our results can be applied to a wide class of models that include higher-spin theories and compactifications of string theory on AdS backgrounds. The modifications of the bulk physics studied in this thesis include massive gravitons, higher-derivative terms in the Einstein-Hilbert action, and new boundary conditions for gravity. We begin by showing that it is possible to construct duals with a massive graviton in the bulk by deforming the dual theory at the boundary. This procedure does not break the translation invariance of the dual theory and might be useful in the study of certain condensed matter systems. We then construct the most general class of parity-even tricritical gravities in three and four dimensions. These higher-derivative theories are not unitary and characterized by the logarithmic fall-off of their linearized perturbations. They are conjectured to be dual to rank-3 logarithmic conformal field theories. We will show that, at linear order in the equations of motion, it is possible to truncate the theory to a unitary subsector. We also show that tricritical gravities in three and four dimensions suffer from a linearization instability that forbids unitary truncations beyond linear order. Finally we consider the role of boundary conditions in the AdS3/CFT2 correspondence. We show that free boundary conditions that lead to enhanced asymptotic symmetry groups are dual to 2D theories of quantum gravity in either the conformal or lightcone gauges. In particular we match the generators of symmetries in the bulk and boundary theories and show that a proper identification of the generator of Virasoro transformations in the bulk leads to a vanishing total central charge. We also show that this identification is consistent with the constraint equations of 2D gravity.

  2. De Sitter brane-world, localization of gravity, and the cosmological constant

    SciTech Connect

    Neupane, Ishwaree P.

    2011-04-15

    Cosmological models with a de Sitter 3-brane embedded in a 5-dimensional de Sitter spacetime (dS{sub 5}) give rise to a finite 4D Planck mass similar to that in Randall-Sundrum (RS) brane-world models in anti-de Sitter 5-dimensional spacetime(AdS{sub 5}). Yet, there arise a few important differences as compared to the results with a flat 3-brane or 4D Minkowski spacetime. For example, the mass reduction formula (MRF) M{sub Pl}{sup 2}=M{sub (5)}{sup 3}l{sub AdS} as well as the relationship M{sub Pl}{sup 2}=M{sub Pl(4+n)}{sup n+2}L{sup n} (with L being the average size or the radius of the n extra dimensions) expected in models of product-space (or Kaluza-Klein) compactifications get modified in cosmological backgrounds. In an expanding universe, a physically relevant MRF encodes information upon the 4-dimensional Hubble expansion parameter, in addition to the length and mass parameters L, M{sub Pl}, and M{sub Pl(4+n)}. If a bulk cosmological constant is present in the solution, then the reduction formula is further modified. With these new insights, we show that the localization of a massless 4D graviton as well as the mass hierarchy between M{sub Pl} and M{sub Pl(4+n)} can be explained in cosmological brane-world models. A notable advantage of having a 5D de Sitter bulk is that in this case the zero-mass wave function is normalizable, which is not necessarily the case if the bulk spacetime is anti-de Sitter. In spacetime dimensions D{>=}7, however, the bulk cosmological constant {Lambda}{sub b} can take either sign ({Lambda}{sub b}<0, =0, or >0). The D=6 case is rather inconclusive, in which case {Lambda}{sub b} may be introduced together with 2-form gauge field (or flux). We obtain some interesting classical gravity solutions that compactify higher-dimensional spacetime to produce a Robertson-Walker universe with de Sitter-type expansion plus one extra noncompact direction. We also show that such models can admit both an effective 4-dimensional Newton constant

  3. Transforming to Lorentz gauge on de Sitter

    SciTech Connect

    Miao, S. P.; Tsamis, N. C.; Woodard, R. P.

    2009-12-15

    We demonstrate that certain gauge fixing functionals cannot be added to the action on backgrounds such as de Sitter, in which a linearization instability is present. We also construct the field-dependent gauge transformation that carries the electromagnetic vector potential from a convenient, non-de Sitter invariant gauge to the de Sitter invariant, Lorentz gauge. The transformed propagator agrees with the de Sitter invariant result previously found by solving the propagator equation in Lorentz gauge. This shows that the gauge transformation technique will eliminate unphysical breaking of de Sitter invariance introduced by a gauge condition. It is suggested that the same technique can be used to finally resolve the issue of whether or not free gravitons are de Sitter invariant.

  4. Note on stability of de Sitter solutions of f(R) theories

    SciTech Connect

    Quiros, Israel; Leyva, Yoelsy; Napoles, Yunelsy

    2009-07-15

    The consequences of the constraints which stability of de Sitter solutions of f(R) theories imposes on the Lagrangian's parameters are investigated within the metric formalism. It is shown, in particular, that several common f(R) Lagrangians do not actually admit matching of local solutions with background de Sitter spaces. Otherwise, asymptotic matching of local solutions of the corresponding models with maximally symmetric spaces of constant curvature is either unstable or anti-de Sitter space is the only stable asymptotic solution. Additional arguments are given in favor of a previous claim that a class of f(R) models comprising both positive and negative powers of R (two different mass scales) could be a nice scenario in which to address, in a united picture, both early-time inflation and late-time accelerated expansion of the Universe. The approach undertaken here is used, also, to check ghost freedom of a Dirac-Born-Infeld modification of general relativity previously studied in the literature.

  5. Thermodynamics of horizons: de Sitter black holes and reentrant phase transitions

    NASA Astrophysics Data System (ADS)

    Kubizňák, David; Simovic, Fil

    2016-12-01

    In this paper we propose a straightforward method for understanding the thermodynamics of black holes in de Sitter space, one that will allow us to study these black holes in a way that is analogous to the anti-de Sitter case. As per usual, we formulate separate thermodynamic first laws for each horizon present in the spacetime, and study their thermodynamics as if they were independent systems characterized by their own temperature. That these systems are not entirely independent and various thermodynamic quantities in them are in fact ‘correlated’ is reflected by the fact that their thermodynamics can be captured by a single Gibbs free energy-like thermodynamic potential. This quantity contains information about possible phase transitions in the system and allows us to uncover a rich phase structure for de Sitter black holes. In particular, we discover reentrant phase transitions for Kerr-dS black holes in six dimensions, a phenomenon recently observed for their six dimensional AdS cousins.

  6. Noncommutative de Sitter and FRW spaces

    NASA Astrophysics Data System (ADS)

    Burić, Maja; Madore, John

    2015-10-01

    Several versions of fuzzy four-dimensional de Sitter space are constructed using the noncommutative frame formalism. Although all noncommutative spacetimes which are found have commutative de Sitter metric as a classical limit, the algebras and the differential calculi which define them have many differences, which we derive and discuss.

  7. de Sitter supergravity model building

    NASA Astrophysics Data System (ADS)

    Kallosh, Renata; Wrase, Timm

    2015-11-01

    We present the explicit de Sitter supergravity action describing the interaction of supergravity with an arbitrary number of chiral and vector multiplets as well as one nilpotent chiral multiplet. The action has a non-Gaussian dependence on the auxiliary field of the nilpotent multiplet; however, it can be integrated out for an arbitrary matter-coupled supergravity. The general supergravity action with a given Kähler potential K , superpotential W and vector matrix fA B interacting with a nilpotent chiral multiplet consists of the standard supergravity action defined by K , W and fA B where the scalar in the nilpotent multiplet has to be replaced by a bilinear combination of the fermion in the nilpotent multiplet divided by the Gaussian value of the auxiliary field. All additional contributions to the action start with terms quartic and higher order in the fermion of the nilpotent multiplet. These are given by a simple universal closed form expression.

  8. Infrared divergences in de Sitter space

    SciTech Connect

    Polarski, D. Service d'Astrophysique, CEN Saclay, 91191 Gif-sur-Yvette CEDEX, France)

    1991-03-15

    Infrared divergences in de Sitter space are considered. It is shown that symmetry breaking is unavoidable only when the infrared divergence is strong enough. The static vacuum has no symmetry breaking despite the presence of an infrared divergence.

  9. de Sitter Space as a Resonance

    NASA Astrophysics Data System (ADS)

    Maltz, Jonathan; Susskind, Leonard

    2017-03-01

    A quantum mechanical formulation of de Sitter cosmological spacetimes still eludes string theory. In this Letter we conjecture a potentially rigorous framework in which the status of de Sitter space is the same as that of a resonance in a scattering process. We conjecture that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant pole characteristic metastable intermediate states. A calculation employing constrained instantons illustrates this idea.

  10. Inflation as de Sitter instability

    NASA Astrophysics Data System (ADS)

    Cadoni, Mariano; Franzin, Edgardo; Mignemi, Salvatore

    2016-09-01

    We consider cosmological inflation generated by a scalar field slowly rolling off from a de Sitter maximum of its potential. The models belong to the class of hilltop models and represent the most general model of this kind in which the scalar potential can be written as the sum of two exponentials. The minimally coupled Einstein-scalar gravity theory obtained in this way is the cosmological version of a two-scale generalization of known holographic models, allowing for solitonic solutions interpolating between an AdS spacetime in the infrared and scaling solutions in the ultraviolet. We then investigate cosmological inflation in the slow-roll approximation. Our model reproduces correctly, for a wide range of its parameters, the most recent experimental data for the power spectrum of primordial perturbations. Moreover, it predicts inflation at energy scales of four to five orders of magnitude below the Planck scale. At the onset of inflation, the mass of the tachyonic excitation, i.e. of the inflaton, turns out to be seven to eight orders of magnitude smaller than the Planck mass.

  11. Remark on massive particle's de Sitter tunneling

    SciTech Connect

    Jiang, Qing-Quan; Chen, De-You; Wen, Dan E-mail: deyouchen@126.com

    2013-11-01

    In the work [J. Y. Zhang and Z. Zhao, Massive particles's black hole tunneling and de Sitter tunneling, Nucl. Phys. B 725 (2005) 173.], the Hawking radiation of the massive particle via tunneling from the de Sitter cosmological horizon has been first described in the tunneling framework. However, the geodesic equation of the massive particle was unnaturally and awkwardly defined there by investigating the relation between the group and phase velocity. In this paper, we start from the Lagrangian analysis on the action to naturally produce the geodesic equation of the tunneling massive particle. Then, based on the new definition for the geodesic equation, we revisit the Hawking radiation of the massive particle via tunneling from the de Sitter cosmological horizon. It is noteworthy that, the highlight of our work is a new and important development of the Parikh-Wilczek's tunneling method, which can make it more physical.

  12. Faddeev-Popov-ghost propagators for Yang-Mills theories and perturbative quantum gravity in the covariant gauge in de Sitter spacetime

    SciTech Connect

    Faizal, Mir; Higuchi, Atsushi

    2008-09-15

    The propagators of the Faddeev-Popov (FP) ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge are infrared (IR) divergent in de Sitter spacetime. We point out, however, that the modes responsible for these divergences will not contribute to loop diagrams in computations of time-ordered products in either Yang-Mills theories or perturbative quantum gravity. Therefore, we propose that the IR-divergent FP-ghost propagator should be regularized by a small mass term that is sent to zero in the end of any perturbative calculations. This proposal is equivalent to using the effective FP-ghost propagators, which we present in an explicit form, obtained by removing the modes responsible for the IR divergences. We also make some comments on the corresponding propagators in anti-de Sitter spacetime.

  13. Cosmological perturbations in inflation and in de Sitter space

    NASA Astrophysics Data System (ADS)

    Pimentel, Guilherme Leite

    holography and entanglement entropy to study superhorizon correlations in quantum field theories in de Sitter space. The entropy has interesting terms that have no equivalent in flat space field theories. These new terms are due to particle creation in an expanding universe. The entropy is calculated directly for free massive scalar theories. For theories with holographic duals, it is determined by the area of some extremal surface in the bulk geometry. We calculate the entropy for different classes of holographic duals. For one of these classes, the holographic dual geometry is an asymptotically Anti-de Sitter space that decays into a crunching cosmology, an open Friedmann-Robertson-Walker universe. The extremal surface used in the calculation of the entropy lies almost entirely on the slice of maximal scale factor of the crunching cosmology.

  14. Nonequilibrium phase transitions and a nonequilibrium critical point from anti-de Sitter space and conformal field theory correspondence.

    PubMed

    Nakamura, Shin

    2012-09-21

    We find novel phase transitions and critical phenomena that occur only outside the linear-response regime of current-driven nonequilibrium states. We consider the strongly interacting (3+1)-dimensional N = 4 large-N(c) SU(N(c)) supersymmetric Yang-Mills theory with a single flavor of fundamental N = 2 hypermultiplet as a microscopic theory. We compute its nonlinear nonballistic quark-charge conductivity by using the AdS/CFT correspondence. We find that the system exhibits a novel nonequilibrium first-order phase transition where the conductivity jumps and the sign of the differential conductivity flips at finite current density. A nonequilibrium critical point is discovered at the end point of the first-order regime. We propose a nonequilibrium steady-state analogue of thermodynamic potential in terms of the gravity-dual theory in order to define the transition point. Nonequilibrium analogues of critical exponents are proposed as well. The critical behavior of the conductivity is numerically confirmed on the basis of these proposals. The present work provides a new example of nonequilibrium phase transitions and nonequilibrium critical points.

  15. {gamma}*{gamma}*{yields}{pi}{sup 0} form factor from anti-de Sitter-space/QCD correspondence

    SciTech Connect

    Stoffers, Alexander; Zahed, Ismail

    2011-08-15

    The recently measured {gamma}*{gamma}*{yields}{pi}{sup 0} anomalous form factor is analyzed using the D4/D8D8 holographic approach to QCD. The half-on-shell transition form factor is vector meson dominated and is shown to exactly tie to the charged-pion form factor. The holographic result compares well with the data for the lowest vector resonance.

  16. Schwinger effect in de Sitter space

    NASA Astrophysics Data System (ADS)

    Fröb, Markus B.; Garriga, Jaume; Kanno, Sugumi; Sasaki, Misao; Soda, Jiro; Tanaka, Takahiro; Vilenkin, Alexander

    2014-04-01

    We consider Schwinger pair production in 1+1 dimensional de Sitter space, filled with a constant electric field E. This can be thought of as a model for describing false vacuum decay beyond the semiclassical approximation, where pairs of a quantum field phi of mass m and charge e play the role of vacuum bubbles. We find that the adiabatic ``in" vacuum associated with the flat chart develops a space-like expectation value for the current J, which manifestly breaks the de Sitter invariance of the background fields. We derive a simple expression for J(E), showing that both ``upward" and ``downward" tunneling contribute to the build-up of the current. For heavy fields, with m2 gg eE,H2, the current is exponentially suppressed, in agreement with the results of semiclassical instanton methods. Here, H is the inverse de Sitter radius. On the other hand, light fields with m ll H lead to a phenomenon of infrared hyperconductivity, where a very small electric field mHlesssimeE ll H2 leads to a very large current J ~ H3/E. We also show that all Hadamard states for phi necessarily break de Sitter invariance. Finally, we comment on the role of initial conditions, and ``persistence of memory" effects.

  17. Schwinger effect in de Sitter space

    SciTech Connect

    Fröb, Markus B.; Garriga, Jaume; Kanno, Sugumi; Sasaki, Misao; Tanaka, Takahiro; Soda, Jiro; Vilenkin, Alexander E-mail: jaume.garriga@ub.edu E-mail: misao@yukawa.kyoto-u.ac.jp E-mail: tanaka@yukawa.kyoto-u.ac.jp

    2014-04-01

    We consider Schwinger pair production in 1+1 dimensional de Sitter space, filled with a constant electric field E. This can be thought of as a model for describing false vacuum decay beyond the semiclassical approximation, where pairs of a quantum field φ of mass m and charge e play the role of vacuum bubbles. We find that the adiabatic ''in'' vacuum associated with the flat chart develops a space-like expectation value for the current J, which manifestly breaks the de Sitter invariance of the background fields. We derive a simple expression for J(E), showing that both ''upward'' and ''downward'' tunneling contribute to the build-up of the current. For heavy fields, with m{sup 2} >> eE,H{sup 2}, the current is exponentially suppressed, in agreement with the results of semiclassical instanton methods. Here, H is the inverse de Sitter radius. On the other hand, light fields with m || H lead to a phenomenon of infrared hyperconductivity, where a very small electric field mH∼Sitter invariance. Finally, we comment on the role of initial conditions, and ''persistence of memory'' effects.

  18. Special Sitters: Teenage Respite Care Providers.

    ERIC Educational Resources Information Center

    Reid, Penny; Legaz, Mary Ann

    1988-01-01

    Camp Fire's Special Sitters Project addresses the need for respite care experienced by parents of disabled children. The project trains teenagers to care for young handicapped children and links the teenagers with parents who call for babysitting service. The project has been successfully replicated in five communities. (Author/JDD)

  19. Quantum Dynamics for de Sitter Radiation

    NASA Astrophysics Data System (ADS)

    Kim, Sang Pyo

    2012-02-01

    We revisit the Hamiltonian formalism for a massive scalar field and study the particle production in a de Sitter space. In the invariant-operator picture the time-dependent annihilation and creation operators are constructed in terms of a complex solution to the classical equation of motion for the field and the Gaussian wave function for each Fourier mode is found which is an exact solution to the Schrödinger equation. The in-out formalism is reformulated by the annihilation and creation operators and the Gaussian wave functions. The de Sitter radiation from the in-out formalism differs from the Gibbons-Hawking radiation in the planar coordinates, and we discuss the discrepancy of the particle production by the two methods.

  20. Cosmic curvature from de Sitter equilibrium cosmology.

    PubMed

    Albrecht, Andreas

    2011-10-07

    I show that the de Sitter equilibrium cosmology generically predicts observable levels of curvature in the Universe today. The predicted value of the curvature, Ω(k), depends only on the ratio of the density of nonrelativistic matter to cosmological constant density ρ(m)(0)/ρ(Λ) and the value of the curvature from the initial bubble that starts the inflation, Ω(k)(B). The result is independent of the scale of inflation, the shape of the potential during inflation, and many other details of the cosmology. Future cosmological measurements of ρ(m)(0)/ρ(Λ) and Ω(k) will open up a window on the very beginning of our Universe and offer an opportunity to support or falsify the de Sitter equilibrium cosmology.

  1. Horizon complementarity in elliptic de Sitter space

    NASA Astrophysics Data System (ADS)

    Hackl, Lucas; Neiman, Yasha

    2015-02-01

    We study a quantum field in elliptic de Sitter space dS4/Z2—the spacetime obtained from identifying antipodal points in dS4. We find that the operator algebra and Hilbert space cannot be defined for the entire space, but only for observable causal patches. This makes the system into an explicit realization of the horizon complementarity principle. In the absence of a global quantum theory, we propose a recipe for translating operators and states between observers. This translation involves information loss, in accordance with the fact that two observers see different patches of the spacetime. As a check, we recover the thermal state at the de Sitter temperature as a state that appears the same to all observers. This thermal state arises from the same functional that, in ordinary dS4, describes the Bunch-Davies vacuum.

  2. De Sitter's theory of Galilean satellites

    NASA Astrophysics Data System (ADS)

    Broer, Henk; Zhao, Lei

    2017-01-01

    In this article, we investigate the mathematical part of De Sitter's theory on the Galilean satellites, and further extend this theory by showing the existence of some quasi-periodic librating orbits by application of KAM theorems. After showing the existence of De Sitter's family of linearly stable periodic orbits in the Jupiter-Io-Europa-Ganymede model by averaging and reduction techniques in the Hamiltonian framework, we further discuss the possible extension of this theory to include a fourth satellite Callisto, and establish the existence of a set of positive measure of quasi-periodic librating orbits in both models for almost all choices of masses among which one sufficiently dominates the others.

  3. de Sitter harmonies: Cosmological spacetimes as resonances

    NASA Astrophysics Data System (ADS)

    Maltz, Jonathan

    2017-03-01

    The aim of this work is to provide the details of a calculation summarized in the recent paper by Maltz and Susskind which conjectured a potentially rigorous framework where the status of de Sitter space is the same as that of a resonance in a scattering process. The conjecture is that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant poles characteristic metastable intermediate states. A calculation employing constrained instantons is presented that illustrates this idea.

  4. De Sitter Space Without Dynamical Quantum Fluctuations

    NASA Astrophysics Data System (ADS)

    Boddy, Kimberly K.; Carroll, Sean M.; Pollack, Jason

    2016-06-01

    We argue that, under certain plausible assumptions, de Sitter space settles into a quiescent vacuum in which there are no dynamical quantum fluctuations. Such fluctuations require either an evolving microstate, or time-dependent histories of out-of-equilibrium recording devices, which we argue are absent in stationary states. For a massive scalar field in a fixed de Sitter background, the cosmic no-hair theorem implies that the state of the patch approaches the vacuum, where there are no fluctuations. We argue that an analogous conclusion holds whenever a patch of de Sitter is embedded in a larger theory with an infinite-dimensional Hilbert space, including semiclassical quantum gravity with false vacua or complementarity in theories with at least one Minkowski vacuum. This reasoning provides an escape from the Boltzmann brain problem in such theories. It also implies that vacuum states do not uptunnel to higher-energy vacua and that perturbations do not decohere while slow-roll inflation occurs, suggesting that eternal inflation is much less common than often supposed. On the other hand, if a de Sitter patch is a closed system with a finite-dimensional Hilbert space, there will be Poincaré recurrences and dynamical Boltzmann fluctuations into lower-entropy states. Our analysis does not alter the conventional understanding of the origin of density fluctuations from primordial inflation, since reheating naturally generates a high-entropy environment and leads to decoherence, nor does it affect the existence of non-dynamical vacuum fluctuations such as those that give rise to the Casimir effect.

  5. De Sitter Transitivity, Conformal Transformations and Conservation Laws

    NASA Astrophysics Data System (ADS)

    Pereira, J. G.; Sampson, A. C.; Savi, L. L.

    2014-02-01

    Minkowski spacetime is transitive under ordinary translations, a transformation that do not have matrix representations. The de Sitter spacetime, on the other hand, is transitive under a combination of translations and proper conformal transformations, which do have a matrix representation. Such matrix, however, is not by itself a de Sitter generator: it gives rise to a conformal re-scaling of the metric, a transformation not belonging to the de Sitter group, and in general not associated with diffeomorphisms in spacetime. When dealing with variational principles and Noether's theorem in de Sitter spacetime, it is necessary to regularize the transformations in order to eliminate the conformal re-scaling of the metric.

  6. Inflation Driven by q-de Sitter

    NASA Astrophysics Data System (ADS)

    Setare, M. R.; Momeni, D.; Kamali, V.; Myrzakulov, R.

    2016-02-01

    We propose a generalised de Sitter scale factor for the cosmology of early and late time universe, including single scalar field is called as inflaton. This form of scale factor has a free parameter q is called as nonextensivity parameter. When q = 1, the scale factor is de Sitter. This scale factor is an intermediate form between power-law and de Sitter. We study cosmology of such families. We show that both kinds of dark components, dark energy and dark matter simultaneously are described by this family of solutions. As a motivated idea, we investigate inflation in the framework of q-de Sitter. We consider three types of scenarios for inflation. In a single inflation scenario, we observe that, inflation ended without any specific ending inflation ϕ e n d , the spectral index and the associated running of the spectral index are n s - 1 ˜ -2 𝜖, α s ≡ 0. To end the inflation: we should have q={3}/{4}. We deduce that the inflation ends when the evolution of the scale factor is a( t) = e 3/4( t). With this scale factor there is no need to specify ϕ e n d . As an alternative to have inflation with ending point, We will study q-inflation model in the context of warm inflation. We propose two forms of damping term Γ. In the first case when Γ = Γ0, we show the scale invariant spectrum, (Harrison-Zeldovich spectrum, i.e. n s = 1) may be approximately presented by (q={9}/{10}, ~N=70). Also there is a range of values of R and n s which is compatible with the BICEP2 data where q={9}/{10}. In case Γ = Γ1 V( ϕ), it is observed that small values of a number of e-folds are assured for small values of q parameter. Also in this case, the scale-invariant spectrum may be represented by (q,N) = ({9}/{10},70). For q={9}/{10} a range of values of R and n s is compatible with the BICEP2 data. Consequently, the proposal of q-de Sitter is consistent with observational data. We observe that the non-extensivity parameter q plays a significant role in inflationary scenario.

  7. Dirac oscillator and nonrelativistic Snyder-de Sitter algebra

    SciTech Connect

    Stetsko, M. M. E-mail: mykola@ktf.franko.lviv.ua

    2015-01-15

    Three dimensional Dirac oscillator was considered in space with deformed commutation relations known as Snyder-de Sitter algebra. Snyder-de Sitter commutation relations give rise to appearance of minimal uncertainties in position as well as in momentum. To derive energy spectrum and wavefunctions of the Dirac oscillator, supersymmetric quantum mechanics and shape invariance technique were applied.

  8. De Sitter uplift with Dynamical Susy Breaking

    NASA Astrophysics Data System (ADS)

    Retolaza, Ander; Uranga, Angel

    2016-04-01

    We propose the use of D-brane realizations of Dynamical Supersymmetry Breaking (DSB) gauge sectors as sources of uplift in compactifications with moduli stabilization onto de Sitter vacua. This construction is fairly different from the introduction of anti D-branes, yet allows for tunably small contributions to the vacuum energy via their embedding into warped throats. The idea is explicitly exemplified by the embedding of the 1-family SU(5) DSB model in a local warped throat with fluxes, which we discuss in detail in terms of orientifolds of dimer diagrams.

  9. Discrete symmetries and de Sitter spacetime

    SciTech Connect

    Cotăescu, Ion I. Pascu, Gabriel

    2014-11-24

    Aspects of the ambiguity in defining quantum modes on de Sitter spacetime using a commuting system composed only of differential operators are discussed. Discrete symmetries and their actions on the wavefunction in commonly used coordinate charts are reviewed. It is argued that the system of commuting operators can be supplemented by requiring the invariance of the wavefunction to combined discrete symmetries- a criterion which selects a single state out of the α-vacuum family. Two such members of this family are singled out by particular combined discrete symmetries- states between which exists a well-known thermality relation.

  10. Gravitational waves in a de Sitter universe

    NASA Astrophysics Data System (ADS)

    Bishop, Nigel T.

    2016-02-01

    The construction of exact linearized solutions to the Einstein equations within the Bondi-Sachs formalism is extended to the case of linearization about de Sitter spacetime. The gravitational wave field measured by distant observers is constructed, leading to a determination of the energy measured by such observers. It is found that gravitational wave energy conservation does not normally apply to inertial observers but that it can be formulated for a class of accelerated observers, i.e., with worldlines that are timelike but not geodesic.

  11. de Sitter Vacua via Consistent D Terms

    SciTech Connect

    Villadoro, Giovanni; Zwirner, Fabio

    2005-12-02

    We introduce a new mechanism for producing locally stable de Sitter or Minkowski vacua, with spontaneously broken N=1 supersymmetry and no massless scalars, applicable to superstring and M-theory compactifications with fluxes. We illustrate the mechanism with a simple N=1 supergravity model that provides parametric control on the sign and the size of the vacuum energy. The crucial ingredient is a gauged U(1) that involves both an axionic shift and an R symmetry, and severely constrains the F- and D-term contributions to the potential.

  12. Constraining de Sitter Space in String Theory.

    PubMed

    Kutasov, David; Maxfield, Travis; Melnikov, Ilarion; Sethi, Savdeep

    2015-08-14

    We argue that the heterotic string does not have classical vacua corresponding to de Sitter space-times of dimension four or higher. The same conclusion applies to type II vacua in the absence of Ramond-Ramond fluxes. Our argument extends prior supergravity no-go results to regimes of high curvature. We discuss the interpretation of the heterotic result from the perspective of dual type II orientifold constructions. Our result suggests that the genericity arguments used in string landscape discussions should be viewed with caution.

  13. Effective Lagrangian in de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Kitamoto, Hiroyuki; Kitazawa, Yoshihisa

    2017-01-01

    Scale invariant fluctuations of metric are a universal feature of quantum gravity in de Sitter spacetime. We construct an effective Lagrangian which summarizes their implications on local physics by integrating superhorizon metric fluctuations. It shows infrared quantum effects are local and render fundamental couplings time dependent. We impose Lorenz invariance on the effective Lagrangian as it is required by the principle of general covariance. We show that such a requirement leads to unique physical predictions by fixing the quantization ambiguities. We explain how the gauge parameter dependence of observables is canceled. In particular the relative evolution speed of the couplings are shown to be gauge invariant.

  14. Spherically Symmetric Space Time with Regular de Sitter Center

    NASA Astrophysics Data System (ADS)

    Dymnikova, Irina

    We formulate the requirements which lead to the existence of a class of globally regular solutions of the minimally coupled GR equations asymptotically de Sitter at the center. The source term for this class, invariant under boosts in the radial direction, is classified as spherically symmetric vacuum with variable density and pressure Tμ ν vac associated with an r-dependent cosmological term Λ μ ν = 8π GTμ ν vac, whose asymptotic at the origin, dictated by the weak energy condition, is the Einstein cosmological term Λgμν, while asymptotic at infinity is de Sitter vacuum with λ < Λ or Minkowski vacuum. For this class of metrics the mass m defined by the standard ADM formula is related to both the de Sitter vacuum trapped at the origin and the breaking of space time symmetry. In the case of the flat asymptotic, space time symmetry changes smoothly from the de Sitter group at the center to the Lorentz group at infinity through radial boosts in between. Geometry is asymptotically de Sitter as r → 0 and asymptotically Schwarzschild at large r. In the range of masses m ≥ mcrit, the de Sitter Schwarzschild geometry describes a vacuum nonsingular black hole (ΛBH), and for m < mcrit it describes G-lump — a vacuum selfgravitating particle-like structure without horizons. In the case of de Sitter asymptotic at infinity, geometry is asymptotically de Sitter as r → 0 and asymptotically Schwarzschild de Sitter at large r. Λμν geometry describes, dependently on parameters m and q = √ {Λ /λ } and choice of coordinates, a vacuum nonsingular cosmological black hole, self-gravitating particle-like structure at the de Sitter background λgμν, and regular cosmological models with cosmological constant evolving smoothly from Λ to λ.

  15. The critical phenomena of charged rotating de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Guo, Xiongying; Li, Huaifan; Zhang, Lichun; Zhao, Ren

    2016-07-01

    In this paper, we investigate the effective thermodynamic quantities in Kerr-Newman-de Sitter spacetime by considering the relations between the black hole event horizon and the cosmological event horizon. We find the effect of the critical point of Kerr-Newman-de Sitter spacetime for the different state parameters. We study the critical phenomena of the system taking different state parameters. This result is consistent with the nature of a liquid-gas phase transition at the critical point, hence deepening the understanding of the analogy of charged de Sitter spacetime and liquid-gas systems.

  16. Vacuum Fluctuation Force on a Rigid Casimir Cavity in de Sitter and Schwarzschild-De Sitter Space-Time

    NASA Astrophysics Data System (ADS)

    Chen, Xiang

    2012-11-01

    We investigate the net force on a rigid Casimir cavity generated by vacuum fluctuations of electromagnetic field in three cases: de Sitter space-time, de Sitter space-time with weak gravitational field and Schwarzschild-de Sitter space-time. In de Sitter space-time the resulting net force follows the square inverse law but unfortunately it is too weak to be measurable due to the large universe radius. By introducing a weak gravitational field into the de Sitter space-time, we find that the net force can now be split into two parts, one is the gravitational force due to the induced effective mass between the two plates and the other one is generated by the metric structure of de Sitter space-time. In order to investigate the vacuum fluctuation force on the rigid cavity under strong gravitational field, we perform a similar analysis in Schwarzschild-de Sitter space-time and results are obtained in three different limits. The most interesting one is when the cavity gets closer to the horizon of a blackhole, square inverse law is recovered and the repulsive force due to negative energy/mass of the cavity now has an observable strength. More importantly the force changes from being repulsive to attractive when the cavity crosses the event horizon, so that the energy/mass of the cavity switches the sign, which suggests the unusual time direction inside the event horizon.

  17. Ghost inflation and de Sitter entropy

    SciTech Connect

    Jazayeri, Sadra; Mukohyama, Shinji; Saitou, Rio; Watanabe, Yota

    2016-08-01

    In the setup of ghost condensation model the generalized second law of black hole thermodynamics can be respected under a radiatively stable assumption that couplings between the field responsible for ghost condensate and matter fields such as those in the Standard Model are suppressed by the Planck scale. Since not only black holes but also cosmology are expected to play important roles towards our better understanding of gravity, we consider a cosmological setup to test the theory of ghost condensation. In particular we shall show that the de Sitter entropy bound proposed by Arkani-Hamed, et al. is satisfied if ghost inflation happened in the early epoch of our universe and if there remains a tiny positive cosmological constant in the future infinity. We then propose a notion of cosmological Page time after inflation.

  18. A de Sitter tachyon thick braneworld

    SciTech Connect

    Germán, Gabriel; Herrera-Aguilar, Alfredo; Malagón-Morejón, Dagoberto; Mora-Luna, Refugio Rigel; Rocha, Roldão da E-mail: aha@fis.unam.mx E-mail: rigel@ifm.umich.mx

    2013-02-01

    Among the multiple 5D thick braneworld models that have been proposed in the last years, in order to address several open problems in modern physics, there is a specific one involving a tachyonic bulk scalar field. Delving into this framework, a thick braneworld with a cosmological background induced on the brane is here investigated. The respective field equations — derived from the model with a warped 5D geometry — are highly non-linear equations, admitting a non-trivial solution for the warp factor and the tachyon scalar field as well, in a de Sitter 4D cosmological background. Moreover, the non-linear tachyonic scalar field, that generates the brane in complicity with warped gravity, has the form of a kink-like configuration. Notwithstanding, the non-linear field equations restricting character does not allow one to easily find thick brane solutions with a decaying warp factor which leads to the localization of 4D gravity and other matter fields. We derive such a thick brane configuration altogether in this tachyon-gravity setup. When analyzing the spectrum of gravity fluctuations in the transverse traceless sector, the 4D gravity is shown to be localized due to the presence of a single zero mode bound state, separated by a continuum of massive Kaluza-Klein (KK) modes by a mass gap. It contrasts with previous results, where there is a KK massive bound excitation providing no clear physical interpretation. The mass gap is determined by the scale of the metric parameter H. Finally, the corrections to Newton's law in this model are computed and shown to decay exponentially. It is in full compliance to corrections reported in previous results (up to a constant factor) within similar braneworlds with induced 4D de Sitter metric, despite the fact that the warp factor and the massive modes have a different form.

  19. Sculpture, cast iron lamps at northeast corner of Stephen Sitter ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Sculpture, cast iron lamps at northeast corner of Stephen Sitter Avenue and Forney road, with scale - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

  20. Biscalar and Bivector Green's Functions in de Sitter Space Time

    PubMed Central

    Narlikar, J. V.

    1970-01-01

    Biscalar and bivector Green's functions of wave equations are calculated explicitly in de Sitter space time. The calculation is performed by considering the electromagnetic field generated by the spontaneous creation of an electric charge. PMID:16591816

  1. Tachyons in classical de Sitter vacua

    NASA Astrophysics Data System (ADS)

    Junghans, Daniel

    2016-06-01

    We revisit the possibility of de Sitter vacua and slow-roll inflation in type II string theory at the level of the classical two-derivative supergravity approximation. Previous attempts at explicit constructions were plagued by ubiquitous tachyons with a large η parameter whose origin has not been fully understood so far. In this paper, we determine and explain the tachyons in two setups that are known to admit unstable dS critical points: an SU(3) structure compactification of massive type IIA with O6-planes and an SU(2) structure compactification of type IIB with O5/O7-planes. We explicitly show that the tachyons are always close to, but never fully aligned with the sgoldstino direction in the considered examples and argue that this behavior is explained by a generalized version of a no-go theorem by Covi et al, which holds in the presence of large mixing in the mass matrix between the sgoldstino and the orthogonal moduli. This observation may also provide a useful stability criterion for general dS vacua in supergravity and string theory.

  2. Charlotte Moore Sitterly: A Life of Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rubin, Vera C.

    2010-01-01

    Dr. Charlotte Moore Sitterly was a scientist in an era when it was rare for a woman to have the opportunity to devote her life to forefront science. Following her graduation from Swarthmore College in 1920, she accepted a position at Princeton University as an assistant to Henry Norris Russell. In 1925 she started a study of the solar spectrum. She could then not know that she would devote much of her scientific career to gathering basic atomic data that are invaluable to the scientific community, even today. In 1931 she obtained a PhD degree at U. California, Berkeley, and returned to Princeton as a staff member of the Princeton University Observatory. In 1945 she moved to the National Bureau of Science (NBS), to supervise preparation of the widely used tables of atomic energy levels. Following the successful lunching (1946) of a V2 rocket to obtain the ultra violet spectrum of the sun, Moore started working with Richard Tousey and his group at the Naval Research Laboratory (NRL). Ultimately, they extended the solar spectrum down to 2200 angstroms. She continued her affiliations with NBS and NRL until her death in 1990. Charlotte Moore was rare scientist who devoted her career to obtaining accurate numbers, thus enabling the scientific community to open her tables and know that the data are accurate.

  3. Hawking's radiation in non-stationary rotating de Sitter background

    NASA Astrophysics Data System (ADS)

    Ibohal, N.; Ibungochouba, T.

    2011-05-01

    Hawking's radiation effect of Klein-Gordon scalar field, Dirac particles and Maxwell's electromagnetic field in the non-stationary rotating de Sitter cosmological space-time is investigated by using a method of generalized tortoise co-ordinates transformation. The locations and the temperatures of the cosmological horizons of the non-stationary rotating de Sitter model are derived. It is found that the locations and the temperatures of the rotating cosmological model depend not only on the time but also on the angle. The stress-energy regularization techniques are applied to the two dimensional analog of the de Sitter metrics and the calculated stress-energy tensor contains the thermal radiation effect.

  4. Thermodynamic properties of black holes in de Sitter space

    NASA Astrophysics Data System (ADS)

    Li, Huai-Fan; Ma, Meng-Sen; Ma, Ya-Qin

    2017-01-01

    We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordström-de Sitter (RNdS) black hole in view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit. By calculating heat capacity and Gibbs free energy, we find SdS black hole is always thermodynamically stable and RNdS black hole may undergoes phase transition at some points.

  5. Holography for a De Sitter-Esque geometry

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; de Buyl, Sophie; Detournay, Stéphane

    2011-05-01

    Warped dS3 arises as a solution to topologically massive gravity (TMG) with positive cosmological constant +1/ ℓ 2 and Chern-Simons coefficient 1/ μ in the region μ 2 ℓ 2 < 27. It is given by a real line fibration over two-dimensional de Sitter space and is equivalent to the rotating Nariai geometry at fixed polar angle. We study the thermodynamic and asymptotic structure of a family of geometries with warped dS3 asymptotics. Interestingly, these solutions have both a cosmological horizon and an internal one, and their entropy is unbounded from above unlike black holes in regular de Sitter space. The asymptotic symmetry group resides at future infinity and is given by a semi-direct product of a Virasoro algebra and a current algebra. The right moving central charge vanishes when μ 2 ℓ 2 = 27/5. We discuss the possible holographic interpretation of these de Sitter-esque spacetimes.

  6. Lifetimes of the 7D excited states of francium

    NASA Astrophysics Data System (ADS)

    Grossman, J. S.; Fliller, R. P., III; Orozco, L. A.; Pearson, M. R.; Sprouse, G. D.

    2000-06-01

    We report our measurement of the lifetimes of the 7D_3/2 and 7D_5/2 levels of francium, using time-correlated single-photon counting techniques. We collect francium atoms in a magneto-optical trap (MOT) in the target room of the superconducting LINAC at Stony Brook. We use two-photon resonant excitation to reach either of the 7D levels. The trapping Ti:Sapph laser operating at 718 nm on the D2 line provides the first photon of the excitation. A second Ti:Sapph probe laser at 969 nm or 961 nm excites the second step to the 7D_3/2 or 7D_5/2 level, respectively. We chop the probe laser and monitor the fluorescent decay to the ground state via the 7P levels using a photomultiplier tube (PMT). The PMT photon-detection pulses are sent to a time to amplitude converter (TAC), and a histogram of the data gives the exponential decay of the fluorescence. Measurements of state lifetimes provide an important check of ab initio calculations of the structure of this simple, heavy atom. In this regard, the d states provide a stringent test that goes beyond the well understood s and p states. Work supported by the NSF.

  7. Temperature and entropy of Schwarzschild de Sitter space-time

    NASA Astrophysics Data System (ADS)

    Shankaranarayanan, S.

    2003-04-01

    In the light of recent interest in quantum gravity in de Sitter space, we investigate semiclassical aspects of four-dimensional Schwarzschild de Sitter space-time using the method of complex paths. The standard semiclassical techniques (such as Bogoliubov coefficients and Euclidean field theory) have been useful to study quantum effects in space-times with single horizons; however, none of these approaches seem to work for Schwarzschild de Sitter space-time or, in general, for space-times with multiple horizons. We extend the method of complex paths to space-times with multiple horizons and obtain the spectrum of particles produced in these space-times. We show that the temperature of radiation in these space-times is proportional to the effective surface gravity—the inverse harmonic sum of surface gravity of each horizon. For the Schwarzschild de Sitter space-time, we apply the method of complex paths to three different coordinate systems—spherically symmetric, Painlevé, and Lemaître. We show that the equilibrium temperature in Schwarzschild de Sitter space-time is the harmonic mean of cosmological and event horizon temperatures. We obtain Bogoliubov coefficients for space-times with multiple horizons by analyzing the mode functions of the quantum fields near the horizons. We propose a new definition of entropy for space-times with multiple horizons, analogous to the entropic definition for space-times with a single horizon. We define entropy for these space-times to be inversely proportional to the square of the effective surface gravity. We show that this definition of entropy for Schwarzschild de Sitter space-time satisfies the D-bound conjecture.

  8. A No-Go Theorem for de Sitter Compactifications?

    NASA Astrophysics Data System (ADS)

    Hari Dass, N. D.

    A general framework for studying compactifications in supergravity and string theories was introduced by Candelas, Horowitz, Strominger and Witten1. This was further generalised to take into account the warp factor by de Wit, Smit and Hari Dass2. Though the prime focus of the latter was to find solutions with nontrivial warp factors (shown not to exist under a variety of circumstances), it was shown there that de Sitter compactifications are generically disfavoured (see also3). In this note we place these results in the context of a revived interest in de Sitter spacetimes.

  9. The fields of uniformly accelerated charges in de Sitter spacetime.

    PubMed

    Bicák, Jirí; Krtous, Pavel

    2002-05-27

    The scalar and electromagnetic fields of charges uniformly accelerated in de Sitter spacetime are constructed. They represent the generalization of the Born solutions describing fields of two particles with hyperbolic motion in flat spacetime. In the limit Lambda-->0, the Born solutions are retrieved. Since in the de Sitter universe the infinities I+/- are spacelike, the radiative properties of the fields depend on the way in which a given point of I+/- is approached. The fields must involve both retarded and advanced effects: Purely retarded fields do not satisfy the constraints at the past infinity I-.

  10. An Analysis of Charged Anisotropic Star with de Sitter Spacetime

    NASA Astrophysics Data System (ADS)

    Das, Kanika; Ali, Nawsad

    2016-02-01

    We propose a model for charged anisotropic star in de Sitter spacetime. We have taken Krori and Barua (J. Phys. A, Math. Gen. 8, 508, 1975) metric in de Sitter spacetime with non-zero cosmological constant. The model is free from singularity. We incorporate the existence of the cosmological constant on a small scale to study the structure of anisotropic charged star. To solve the Einstein-Maxwell field equations we assume the relation between the radial and transverse pressure as p t - p r = g q( r)2 r 2 (where g is a non-zero positive constant). The physical conditions inside the stellar model are also discussed.

  11. Recurrent Nightmares?: Measurement Theory in de Sitter Space

    NASA Astrophysics Data System (ADS)

    Banks, Tom; Fischler, Willy; Paban, Sonia

    2002-12-01

    The idea that asymptotic de Sitter space can be described by a finite Hilbert Space implies that any quantum measurement has an irreducible innacuracy. We argue that this prevents any measurement from verifying the existence of the Poincaré recurrences that occur in the mathematical formulation of quantum de Sitter (dS) space. It also implies that the mathematical quantum theory of dS space is not unique. There will be many different hamiltonians, which give the same results, within the uncertainty in all possible measurements.

  12. Aspects of Symmetry in de Sitter Space

    NASA Astrophysics Data System (ADS)

    Ng, Gim Seng

    We study various aspects of symmetry in four-dimensional de Sitter space (dS4). The asymptotic symmetry group at future null infinity (I+) of dS4 is shown to be given by the group of three-dimensional diffeomorphisms acting on I+. However, for physics relevant to an eternal observatory in dS4, we should instead impose unconventional future boundary conditions at I+. These boundary conditions violate conventional causality, but we argue the causality violations cannot be detected by any experiment in the observatory. As the next step, we study the relevant dynamics in quantum dS4 by illuminating some previously inaccessible aspects of the dS/CFT dictionary in the context of the higher spin dS4/CFT3 correspondence relating Vasiliev's higher-spin gravity on dS4 to a Euclidean Sp(N) CFT3 . We found that CFT3 states created by operator insertions are found to be dual to (anti) quasinormal modes (QNM) in the bulk. A R-norm is defined on the R3 bulk Hilbert space and shown for the scalar case to be equivalent to both the Zamolodchikov and pseudounitary C-norm of the Sp(N) CFT3. The QNMs are found to lie in two complex highest-weight representations of the dS4 isometry group and form a complete orthogonal basis with respect to the R-norm. The conventional Euclidean vacuum may be defined as the state annihilated by half of the QNMs, and the Euclidean Green function is obtained from a simple mode sum. Finally, as a step towards understanding non-linear dynamics of dS 4 we study both linear and non-linear deformations of dS4 which leave the induced conformal metric and trace of the extrinsic curvature unchanged for a fixed hypersurface. These deformations are required to be regular at the future horizon of the static patch observer. When the slices are arbitrarily close to the cosmological horizon, the finite deformations are characterized by solutions to the incompressible Navier-Stokes equation.

  13. How to use retarded Green's functions in de Sitter spacetime

    SciTech Connect

    Higuchi, Atsushi; Cheong, Lee Yen

    2008-10-15

    We demonstrate in examples that the covariant retarded Green's functions in electromagnetism and linearized gravity work as expected in de Sitter spacetime. We first clarify how retarded Green's functions should be used in spacetimes with spacelike past infinity such as de Sitter spacetime. In particular, we remind the reader of a general formula which gives the field for given initial data on a Cauchy surface and a given source (a charge or stress-energy tensor distribution) in its future. We then apply this formula to three examples: (i) electromagnetism in the future of a Cauchy surface in Minkowski spacetime, (ii) electromagnetism in de Sitter spacetime, and (iii) linearized gravity in de Sitter spacetime. In each example the field is reproduced correctly as predicted by the general argument. In the third example we construct a linearized gravitational field from two equal point masses located at the 'North and South Poles' which is nonsingular on the cosmological horizon and satisfies a covariant gauge condition and show that this field is reproduced by the retarded Green's function with corresponding gauge parameters.

  14. Attractor states and quantum instabilities in de Sitter space

    SciTech Connect

    Anderson, P. R.; Eaker, W.; Habib, S.; Molina-Paris, Carmen; Mottola, E.

    2001-01-01

    The asymptotic behavior of the energy-momentum tensor for a free quantized scalar field with mass m and curvature coupling {zeta} in de Sitter space is investigated. It is shown that for an arbitrary, homogeneous and isotropic, fourth order adiabatic state for which the two-point function is infrared finite, approaches the Bunch-Davies de Sitter invariant value at late times if m{sup 2} + {zeta}R > 0. In the case m = {zeta} = 0, the energy-momentum tensor approaches the de Sitter invariant Allen-Folacci value for such a state. For m{sup 2} + {zeta}R = 0, but m and {zeta} not separately zero it is shown that at late times grows linearly in terms of cosmic time leading to an instability of de Sitter space. The asymptotic behavior is again independent of the state of the field. For m{sup 2} + {zeta}R < 0, it is shown that, for most values of m and {zeta}, grows exponentially in terms of cosmic time at late times in a state dependent manner.

  15. Further investigations of the Kerr--de Sitter space

    SciTech Connect

    Khanal, U.

    1985-08-15

    Some recursion relations pertaining to the radial functions of Dirac, electromagnetic, and gravitational fields in the Kerr--de Sitter universe are proved. The behavior of the tortoise coordinate is investigated and it is shown that super radiance can also occur in this space.

  16. de Sitter Tunneling, Emission Spectrum and Entropy/Area Quantum

    NASA Astrophysics Data System (ADS)

    Jiang, Qing-Quan

    2012-08-01

    The Banerjee—Majhi's recent work shows that the Hawking radiation and entropy/area quantum of the black hole horizon (EH) can be well described in the tunneling picture. In this paper, we develop this idea to the case of a de Sitter tunneling from the cosmological horizon (CH), and obtain the Hawking emission spectrum and entropy/area spectroscopy from the CH of the purely de Sitter black hole as well as the Schwarzschild-de Sitter black hole. It is interestingly found that the area of the CH is quantized by ΔA = 4l2pl, as was given by Hod for the area quantum of -the EH by considering the Heisenberg uncertainty principle and Schwinger-type emission process. Also, we conclude from our derivation that the entropy/area quantum of the CH is universal in the sense that it is independent of the black hole parameters. This realization implies that, (at least) at a semiclassical level, the de Sitter gravity shares the similar quantum behavior as the usual gravity without presence of a cosmological constant.

  17. Anti-de Sitter 5D black hole solutions with a self-interacting bulk scalar field: A potential reconstruction approach

    SciTech Connect

    Farakos, K.; Kouretsis, A. P.; Pasipoularides, P.

    2009-09-15

    We construct asymptotically AdS black hole solutions, with a self-interacting bulk scalar field, in the context of 5D general relativity. As the observable universe is characterized by spatial flatness, we focus on solutions where the horizon of the black hole, and subsequently all 3D hypersurfaces for fixed radial coordinate, have zero spatial curvature. We examine two cases for the black hole scalar hair: (a) an exponential decaying scalar field profile and (b) an inverse power scalar field profile. The scalar black hole solutions we present in this paper are characterized by four functions f(r), a(r), {phi}(r), and V({phi}(r)). Only the functions {phi}(r) and a(r) are determined analytically, while the functions f(r) and V({phi}(r)) are expressed semianalytically by integral formulas in terms of a(r). We present our numerical results and study in detail the characteristic properties of our solutions. We also note that the potential we obtain has a nonconvex form in agreement with the corresponding 'no hair theorem' for AdS spacetimes.

  18. Existence of topological hairy dyons and dyonic black holes in anti-de Sitter su(N) Einstein-Yang-Mills theory

    SciTech Connect

    Baxter, J. Erik

    2016-02-15

    We investigate dyonic black hole and dyon solutions of four-dimensional su(N) Einstein-Yang-Mills theory with a negative cosmological constant. We derive a set of field equations in this case, and prove the existence of non-trivial solutions to these equations for any integer N, with 2N − 2 gauge degrees of freedom. We do this by showing that solutions exist locally at infinity, and at the event horizon for black holes and the origin for solitons. We then prove that we can patch these solutions together regularly into global solutions that can be integrated arbitrarily far into the asymptotic regime. Our main result is to show that dyonic solutions exist in open sets in the parameter space, and hence that we can find non-trivial dyonic solutions in a number of regimes whose magnetic gauge fields have no zeros, which is likely important to the stability of the solutions.

  19. Instanton transition in thermal and moduli deformed de Sitter cosmology

    NASA Astrophysics Data System (ADS)

    Kounnas, Costas; Partouche, Hervé

    2008-04-01

    We consider the de Sitter cosmology deformed by the presence of a thermal bath of radiation and/or time-dependent moduli fields. Depending on the parameters, either a first or second-order phase transition can occur. In the first case, an instanton allows a double analytic continuation. It induces a probability to enter the inflationary evolution by tunnel effect from another cosmological solution. The latter starts with a big bang and, in the case the transition does not occur, ends with a big crunch. A temperature duality exchanges the two cosmological branches. In the limit where the pure de Sitter universe is recovered, the tunnel effect reduces to a “creation from nothing”, due to the vanishing of the big bang branch. However, the latter may be viable in some range of the deformation parameter. In the second case, there is a smooth evolution from a big bang to the inflationary phase.

  20. Fermionic Schwinger effect and induced current in de Sitter space

    SciTech Connect

    Hayashinaka, Takahiro; Fujita, Tomohiro; Yokoyama, Jun’ichi

    2016-07-08

    We explore Schwinger effect of spin 1/2 charged particles with static electric field in 1+3 dimensional de Sitter spacetime. We analytically calculate the vacuum expectation value of the spinor current which is induced by the produced particles in the electric field. The renormalization is performed with the adiabatic subtraction scheme. We find that the current becomes negative, namely it flows in the direction opposite to the electric field, if the electric field is weaker than a certain threshold value depending on the fermion mass, which is also known to happen in the case of scalar charged particles in 1+3 de Sitter spacetime. Contrary to the scalar case, however, the IR hyperconductivity is absent in the spinor case.

  1. Refining the boundaries of the classical de Sitter landscape

    NASA Astrophysics Data System (ADS)

    Andriot, David; Blåbäck, Johan

    2017-03-01

    We derive highly constraining no-go theorems for classical de Sitter backgrounds of string theory, with parallel sources; this should impact the embedding of cosmological models. We study ten-dimensional vacua of type II supergravities with parallel and backreacted orientifold O p -planes and D p -branes, on four-dimensional de Sitter spacetime times a compact manifold. Vacua for p = 3, 7 or 8 are completely excluded, and we obtain tight constraints for p = 4, 5, 6. This is achieved through the derivation of an enlightening expression for the four-dimensional Ricci scalar. Further interesting expressions and no-go theorems are obtained. The paper is self-contained so technical aspects, including conventions, might be of more general interest.

  2. One loop graviton corrections to dynamical photons in de Sitter

    NASA Astrophysics Data System (ADS)

    Glavan, D.; Miao, S. P.; Prokopec, Tomislav; Woodard, R. P.

    2017-04-01

    We employ a recent, general gauge computation of the one loop graviton contribution to the vacuum polarization on de Sitter to solve for one loop corrections to the photon mode function. The vacuum polarization takes the form of a gauge independent, spin 2 contribution and a gauge dependent, spin 0 contribution. We show that the leading secular corrections derive entirely from the spin 2 contribution.

  3. Stability of black holes in de Sitter space

    SciTech Connect

    Mellor, F.; Moss, I. )

    1990-01-15

    The theory of black-hole perturbations is extended to charged black holes in de Sitter space. These spacetimes have wormholes connecting different asymptotic regions. It appears that, at least in some cases, these holes are stable even at the Cauchy horizon. It follows that they violate cosmic censorship and an observer could in principle travel through the black hole to another universe. The stability of these spacetimes also implies the existence of a cosmological no hair'' theorem.

  4. Dynamics of test bodies with spin in de Sitter spacetime

    SciTech Connect

    Obukhov, Yuri N.; Puetzfeld, Dirk

    2011-02-15

    We study the motion of spinning test bodies in the de Sitter spacetime of constant positive curvature. With the help of the 10 Killing vectors, we derive the 4-momentum and the tensor of spin explicitly in terms of the spacetime coordinates. However, in order to find the actual trajectories, one needs to impose the so-called supplementary condition. We discuss the dynamics of spinning test bodies for the cases of the Frenkel and Tulczyjew conditions.

  5. Semiclassical fermion pair creation in de Sitter spacetime

    SciTech Connect

    Stahl, Clément Eckhard, Strobel

    2015-12-17

    We present a method to semiclassically compute the pair creation rate of bosons and fermions in de Sitter spacetime. The results in the bosonic case agree with the ones in the literature. We find that for the constant electric field the fermionic and bosonic pair creation rate are the same. This analogy of bosons and fermions in the semiclassical limit is known from several flat spacetime examples.

  6. The solar photon thruster as a terrestrial pole sitter.

    PubMed

    Matloff, Gregory L

    2004-05-01

    Geosynchronous satellites are invisible at high latitudes. A pole-sitting spacecraft would have communication, climate-studies, and near-polar Earth observation applications. We present a pole-sitter based on the solar photon thruster (SPT), a two-sail variant of the solar sail using a large curved collector sail (always normal to the Sun) to direct sunlight against a much smaller thruster. Thrust decreases slower for an SPT than for a conventional sail arrangement as the angle between sunlight and the collector normal increases. An SPT pole-sitter is offset from the terrestrial pole so that a component of Earth gravity balances the solar radiation-pressure component pushing the SPT off station. The component of gravitational attraction of the Earth pulling the spacecraft towards Earth is also balanced by a solar radiation-pressure component. Results are presented for 80-100% collector/thruster reflectivities. For a spacecraft areal mass thickness of 0.002 kg/m(2), collector and thruster reflectivities of 0.9, the SPT can be situated above latitude 45 degrees at a distance of approximately 60 Earth radii. An SPT pole sitter would be affected by lunar perturbation, which can be compensated for by an on-board rocket thruster producing 2 x 10(-6) g acceleration, a second SPT thruster sail thrusting against the influence of the Moon, or by directing a microwave beam against the spacecraft. Since an SPT pole sitter is in a position rather than an orbit, the effect of terrestrial gravitation limits the size and design of the payload package, which limits terrestrial target resolution.

  7. Universe Without Singularities A Group Approach to De Sitter Cosmology

    NASA Astrophysics Data System (ADS)

    Licata, Ignazio

    2006-05-01

    In the last years the traditional scenario of ``Big Bang'' has been deeply modified by the study of the quantum features of the Universe evolution, proposing again the problem of using ``local'' physical laws on cosmic scale, with particular regard to the cosmological constant role. The ``group extention'' method shows that the De Sitter group univocally generalizes the Poincaré group, formally justifies the cosmological constant use and suggests a new interpretation for Hartle-Hawking boundary conditions in Quantum Cosmology.

  8. Probing Planckian physics in de Sitter space with quantum correlations

    SciTech Connect

    Feng, Jun; Zhang, Yao-Zhong; Gould, Mark D.; Fan, Heng; Sun, Cheng-Yi; Yang, Wen-Li

    2014-12-15

    We study the quantum correlation and quantum communication channel of both free scalar and fermionic fields in de Sitter space, while the Planckian modification presented by the choice of a particular α-vacuum has been considered. We show the occurrence of degradation of quantum entanglement between field modes for an inertial observer in curved space, due to the radiation associated with its cosmological horizon. Comparing with standard Bunch–Davies choice, the possible Planckian physics causes some extra decrement on the quantum correlation, which may provide the means to detect quantum gravitational effects via quantum information methodology in future. Beyond single-mode approximation, we construct proper Unruh modes admitting general α-vacua, and find a convergent feature of both bosonic and fermionic entanglements. In particular, we show that the convergent points of fermionic entanglement negativity are dependent on the choice of α. Moreover, an one-to-one correspondence between convergent points H{sub c} of negativity and zeros of quantum capacity of quantum channels in de Sitter space has been proved. - Highlights: • Quantum correlation and quantum channel in de Sitter space are studied. • Gibbons–Hawking effect causes entanglement degradation for static observer. • Planckian physics causes extra decrement on quantum correlation. • Convergent feature of negativity relies on the choice of alpha-vacua. • Link between negativity convergence and quantum channel capacity is given.

  9. Massless scalar field vacuum in de Sitter spacetime

    SciTech Connect

    Page, Don N.; Wu, Xing E-mail: xwu5@ualberta.ca

    2012-11-01

    As a spacetime with compact spatial sections, de Sitter spacetime does not have a de Sitter-invariant ground state for a minimally-coupled massless scalar field that gives definite expectation values for any observables not invariant under constant shifts of the field. However, if one restricts to observables that are shift invariant, as the action is, then there is a unique vacuum state. Here we calculate the shift-invariant four-point function that is the vacuum expectation value of the product of the difference of the field values at one pair of points and of the difference of the field values at a second pair of points. We show that this vacuum expectation value obeys a cluster-decomposition property of vanishing in the limit that the one pair of points is moved arbitrarily far from the other pair. We also calculate the shift-invariant correlation of the gradient of the scalar field at two different points and show that it also obeys a cluster-decomposition property. Possible relevance to a putative de Sitter-invariant quantum state for gravity is discussed.

  10. Short distance physics of the inflationary de Sitter universe

    SciTech Connect

    Ali, Ahmed Farag; Faizal, Mir; Khalil, Mohammed M. E-mail: f2mir@uwaterloo.ca

    2015-09-01

    In this work, we investigate inflationary cosmology using scalar field theory deformed by the generalized uncertainty principle (GUP) containing a linear momentum term. Apart from being consistent with the existence of a minimum measurable length scale, this GUP is also consistent with doubly special relativity and hence with the existence of maximum measurable momentum. We use this deformed scalar field theory to analyze the tensor and scalar mode equations in a de Sitter background, and to calculate modifications to the tensor-to-scalar ratio. Finally, we compare our results for the tensor-to-scalar ratio with the Planck data to constrain the minimum length parameter in the GUP.

  11. One-loop gravitational wave spectrum in de Sitter spacetime

    SciTech Connect

    Fröb, Markus B.; Verdaguer, Enric

    2012-08-01

    The two-point function for tensor metric perturbations around de Sitter spacetime including one-loop corrections from massless conformally coupled scalar fields is calculated exactly. We work in the Poincare patch (with spatially flat sections) and employ dimensional regularization for the renormalization process. Unlike previous studies we obtain the result for arbitrary time separations rather than just equal times. Moreover, in contrast to existing results for tensor perturbations, ours is manifestly invariant with respect to the subgroup of de Sitter isometries corresponding to a simultaneous time translation and rescaling of the spatial coordinates. Having selected the right initial state for the interacting theory via an appropriate iε prescription is crucial for that. Finally, we show that although the two-point function is a well-defined spacetime distribution, the equal-time limit of its spatial Fourier transform is divergent. Therefore, contrary to the well-defined distribution for arbitrary time separations, the power spectrum is strictly speaking ill-defined when loop corrections are included.

  12. A note on entropy of de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sourav

    2016-03-01

    A de Sitter black hole or a black hole spacetime endowed with a positive cosmological constant has two Killing horizons—a black hole and a cosmological event horizon surrounding it. It is natural to expect that the total Bekenstein-Hawking entropy of such spacetimes should be the sum of the two horizons' areas. In this work we apply the recently developed formalism using the Gibbons-Hawking-York boundary term and the near horizon symmetries to derive the total entropy of such two horizon spacetimes. We construct a suitable general geometric set up for general stationary axisymmetric spacetimes with two or more than two commuting Killing vector fields in an arbitrary spacetime dimensions. This framework helps us to deal with both horizons on an equal footing. We show that in order to obtain the total entropy of such spacetimes, the near horizon mode functions for the diffeomorphism generating vector fields have to be restricted in a certain manner, compared to the single horizon spacetimes. We next discuss specific known exact solutions belonging to the Kerr-Newman or the Plebanski-Demianski-de Sitter families to show that they fall into the category of our general framework. We end with a sketch of further possible extensions of this work.

  13. One-loop gravitational wave spectrum in de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Fröb, Markus B.; Roura, Albert; Verdaguer, Enric

    2012-08-01

    The two-point function for tensor metric perturbations around de Sitter spacetime including one-loop corrections from massless conformally coupled scalar fields is calculated exactly. We work in the Poincaré patch (with spatially flat sections) and employ dimensional regularization for the renormalization process. Unlike previous studies we obtain the result for arbitrary time separations rather than just equal times. Moreover, in contrast to existing results for tensor perturbations, ours is manifestly invariant with respect to the subgroup of de Sitter isometries corresponding to a simultaneous time translation and rescaling of the spatial coordinates. Having selected the right initial state for the interacting theory via an appropriate iepsilon prescription is crucial for that. Finally, we show that although the two-point function is a well-defined spacetime distribution, the equal-time limit of its spatial Fourier transform is divergent. Therefore, contrary to the well-defined distribution for arbitrary time separations, the power spectrum is strictly speaking ill-defined when loop corrections are included.

  14. Separability of Gravitational Perturbation in Generalized Kerr-Nut Sitter Space-Time

    NASA Astrophysics Data System (ADS)

    Oota, Takeshi; Yasui, Yukinori

    Generalized Kerr-NUT-de Sitter space-time is the most general space-time which admits a rank-2 closed conformal Killing-Yano tensor. It contains the higher-dimensional Kerr-de Sitter black holes with partially equal angular momenta. We study the separability of gravitational perturbations in the generalized Kerr-NUT-de Sitter space-time. We show that a certain type of tensor perturbations admits the separation of variables. The linearized perturbation equations for the Einstein condition are transformed into the ordinary differential equations of Fuchs type.

  15. Scale-invariant spectrum of Lee-Wick model in de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Myung, Yun Soo; Moon, Taeyoon

    2015-02-01

    We obtain a scale-invariant spectrum from the Lee-Wick model in de Sitter spacetime. This model is a fourth-order scalar theory whose mass parameter is determined by M2=2H2. The Harrison-Zel'dovich scale-invariant spectrum is obtained by Fourier transforming the propagator in position space as well as by computing the power spectrum directly. It shows clearly that the LW scalar theory provides a truly scale-invariant spectrum in whole de Sitter, while the massless scalar propagation in de Sitter shows a scale-invariant spectrum in the superhorizon region only.

  16. Open quantum system approach to the Gibbons-Hawking effect of de Sitter space-time.

    PubMed

    Yu, Hongwei

    2011-02-11

    We analyze, in the paradigm of open quantum systems, the reduced dynamics of a freely falling two-level detector in de Sitter space-time in weak interaction with a reservoir of fluctuating quantized conformal scalar fields in the de Sitter-invariant vacuum. We find that the detector is asymptotically driven to a thermal state at the Gibbons-Hawking temperature, regardless of its initial state. Our discussion, therefore, shows that the Gibbons-Hawking effect of de Sitter space-time can be understood as a manifestation of thermalization phenomena that involves decoherence and dissipation in open quantum systems.

  17. Quantum statistical entropy for Kerr de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Chun; Wu, Yue-Qin; Zhao, Ren

    2004-06-01

    Improving the membrane model by which the entropy of the black hole is studied, we study the entropy of the black hole in the non-thermal equilibrium state. To give the problem stated here widespread meaning, we discuss the (n+2)-dimensional de Sitter spacetime. Through discussion, we obtain that the black hole's entropy which contains two horizons (a black hole's horizon and a cosmological horizon) in the non-thermal equilibrium state comprises the entropy corresponding to the black hole's horizon and the entropy corresponding to the cosmological horizon. Furthermore, the entropy of the black hole is a natural property of the black hole. The entropy is irrelevant to the radiation field out of the horizon. This deepens the understanding of the relationship between black hole's entropy and horizon's area. A way to study the bosonic and fermionic entropy of the black hole in high non-thermal equilibrium spacetime is given.

  18. Nonlinear Laplace equation, de Sitter vacua, and information geometry

    SciTech Connect

    Loran, Farhang

    2005-06-15

    Three exact solutions say {phi}{sub 0} of massless scalar theories on Euclidean space, i.e. D=6 {phi}{sup 3}, D=4 {phi}{sup 4} and D=3 {phi}{sup 6} models are obtained which share similar properties. The information geometry of their moduli spaces coincide with the Euclidean AdS{sub 7}, AdS{sub 5} and AdS{sub 4} respectively on which {phi}{sub 0} can be described as a stable tachyon. In D=4 we recognize that the SU(2) instanton density is proportional to {phi}{sub 0}{sup 4}. The original action S[{phi}] written in terms of new scalars {phi}-tilde={phi}-{phi}{sub 0} is shown to be equivalent to an interacting scalar theory on D-dimensional de Sitter background.

  19. Entanglement entropy of α-vacua in de Sitter space

    NASA Astrophysics Data System (ADS)

    Kanno, Sugumi; Murugan, Jeff; Shock, Jonathan P.; Soda, Jiro

    2014-07-01

    We consider the entanglement entropy of a free massive scalar field in the one parameter family of α-vacua in de Sitter space by using a method developed by Maldacena and Pimentel. An α-vacuum can be thought of as a state filled with particles from the point of view of the Bunch-Davies vacuum. Of all the α-vacua we find that the entanglement entropy takes the minimal value in the Bunch-Davies solution. We also calculate the asymptotic value of the Rényi entropy and find that it increases as α increases. We argue these features stem from pair condensation within the non-trivial α-vacua where the pairs have an intrinsic quantum correlation.

  20. De Sitter space in gauge/gravity duality

    NASA Astrophysics Data System (ADS)

    Anguelova, Lilia; Suranyi, Peter; Wijewardhana, L. C. R.

    2015-10-01

    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) dS 4 spacetime. Finally, we comment on the implications of our dS4 solutions for building gravity duals of Glueball Inflation.

  1. Dynamics of black holes in de Sitter spacetimes

    NASA Astrophysics Data System (ADS)

    Zilhão, Miguel; Cardoso, Vitor; Gualtieri, Leonardo; Herdeiro, Carlos; Sperhake, Ulrich; Witek, Helvi

    2012-05-01

    Nonlinear dynamics in cosmological backgrounds has the potential to teach us immensely about our Universe, and also to serve as prototype for nonlinear processes in generic curved spacetimes. Here we report on dynamical evolutions of black holes in asymptotically de Sitter spacetimes. We focus on the head-on collision of equal mass binaries and for the first time compare analytical and perturbative methods with full blown nonlinear simulations. Our results include an accurate determination of the merger/scatter transition (consequence of an expanding background) for small mass binaries and a test of the cosmic censorship conjecture, for large mass binaries. We observe that, even starting from small separations, black holes in large mass binaries eventually lose causal contact, in agreement with the conjecture.

  2. Energy, momentum and angular momentum conservations in de Sitter gravity

    NASA Astrophysics Data System (ADS)

    Lu, Jia-An

    2016-08-01

    In de Sitter (dS) gravity, where gravity is a gauge field introduced to realize the local dS invariance of the matter field, two kinds of conservation laws are derived. The first kind is a differential equation for a dS-covariant current, which unites the canonical energy-momentum (EM) and angular momentum (AM) tensors. The second kind presents a dS-invariant current which is conserved in the sense that its torsion-free divergence vanishes. The dS-invariant current unites the total (matter plus gravity) EM and AM currents. It is well known that the AM current contains an inherent part, called the spin current. Here it is shown that the EM tensor also contains an inherent part, which might be observed by its contribution to the deviation of the dust particle’s world line from a geodesic. All the results are compared to the ordinary Lorentz gravity.

  3. Kapteyn and de Sitter; a rare and special teacher-student and coach-player relationship

    NASA Astrophysics Data System (ADS)

    de Sitter, Wolter Reinold

    Measured along the yardstick of subsequent success, Willem de Sitter [1872-1934] was one of Kapteyn's foremost pupils along with van Rhijn, Schilt and Jan Hendrik Oort. From his appointment as professor at Leiden University in 1908 until Kapteyn's death in 1922, de Sitter maintained in close contact with his teacher. Kapteyn was his trusted sounding board and consultant in scientific and administrative matters, as well as academic politics. De Sitter had his ideas on a complete reorganisation and restructuring of Leiden Observatory scrutinized by Kapteyn's experienced judgement, and together they developed ideas and completed a plan of action, including touchy staffing, salary and budgettary aspects. Together they were a formidable team and operated as such. Notes by de Sitter and many letters from Kapteyn illustrate their fruitful relationship.

  4. Interpretational conflicts between the static and non-static forms of the de Sitter metric.

    PubMed

    Mitra, Abhas

    2012-01-01

    The de-Sitter metric is a special form of the non-static Friedmann metric, and appears to be genuinely non-static since it describes the initial exponential expansion of the Big Bang universe. However, the de Sitter metric appears to be perfectly static in the Schwarzschild frame where the vacuum fluid is supposed to be in motion. Here we highlight the conflicts between the static and non-static versions of the de-Sitter metric from a physical perspective. In particular, while the "Principle of Energy Conservation" is honored in one case, the same is badly violated for the other. However, we offer a partial resolution of such conflicts by deriving the static de Sitter metric by solving the relevant field equations. It is seen that, it is the very special vacuum equation of state pressure = -density which results in the static form even when the vacuum fluid is supposed to be in motion.

  5. Do scale-invariant fluctuations imply the breaking of de Sitter invariance?

    NASA Astrophysics Data System (ADS)

    Youssef, A.

    2013-01-01

    The quantization of the massless minimally coupled (mmc) scalar field in de Sitter spacetime is known to be a non-trivial problem due to the appearance of strong infrared (IR) effects. In particular, the scale-invariance of the CMB power-spectrum - certainly one of the most successful predictions of modern cosmology - is widely believed to be inconsistent with a de Sitter invariant mmc two-point function. Using a Cesaro-summability technique to properly define an otherwise divergent Fourier transform, we show in this Letter that de Sitter symmetry breaking is not a necessary consequence of the scale-invariant fluctuation spectrum. We also generalize our result to the tachyonic scalar fields, i.e. the discrete series of representations of the de Sitter group, that suffer from similar strong IR effects.

  6. Quantum Linear Gravity in de Sitter Universe on Gupta-Bleuler Vacuum State

    NASA Astrophysics Data System (ADS)

    Enayati, M.; Takook, M. V.; Rouhani, S.

    2017-04-01

    Application of Krein space quantization to the linear gravity in de Sitter space-time have constructed on Gupta-Bleuler vacuum state, resulting in removal of infrared divergence and preserving de Sitter covariant. By pursuing this path, the non uniqueness of vacuum expectation value of the product of field operators in curved space-time disappears as well. Then the vacuum expectation value of the product of field operators can be defined properly and uniquely.

  7. Contribution of the cosmological constant to the bending of light in Kerr-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Sultana, Joseph

    2013-08-01

    We examine the effect of the cosmological constant Λ on the angle of deflection of null geodesics in the equatorial plane of the Kerr-de Sitter spacetime. This is done by employing a procedure used recently by Rindler and Ishak to obtain the bending angle of light in the Schwarzschild-de Sitter geometry. We show that this approach yields a contribution from the cosmological constant in the expression for the bending angle.

  8. Graviton emission from simply rotating Kerr-de Sitter black holes: Transverse traceless tensor graviton modes

    SciTech Connect

    Doukas, Jason; Cho, H. T.; Cornell, A. S.; Naylor, Wade

    2009-08-15

    In this article we present results for tensor graviton modes (in seven dimensions and greater, n{>=}3) for gray-body factors of Kerr-de Sitter black holes and for Hawking radiation from simply rotating (n+4)-dimensional Kerr black holes. Although there is some subtlety with defining the Hawking temperature of a Kerr-de Sitter black hole, we present some preliminary results for emissions assuming the standard Hawking normalization and a Bousso-Hawking-like normalization.

  9. Holography and quantum states in elliptic de Sitter space

    NASA Astrophysics Data System (ADS)

    Halpern, Illan F.; Neiman, Yasha

    2015-12-01

    We outline a program for interpreting the higher-spin dS/CFT model in terms of physics in the causal patch of a dS observer. The proposal is formulated in "elliptic" de Sitter space d{S}_4/{Z}_2 , obtained by identifying antipodal points in dS 4. We discuss recent evidence that the higher-spin model is especially well-suited for this, since the antipodal symmetry of bulk solutions has a simple encoding on the boundary. For context, we test some other (free and interacting) theories for the same property. Next, we analyze the notion of quantum field states in the non-time-orientable d{S}_4/{Z}_2 . We compare the physics seen by different observers, with the outcome depending on whether they share an arrow of time. Finally, we implement the marriage between higher-spin holography and observers in d{S}_4/{Z}_2 , in the limit of free bulk fields. We succeed in deriving an observer's operator algebra and Hamiltonian from the CFT, but not her S-matrix. We speculate on the extension of this to interacting higher-spin theory.

  10. Castles in the Air: The Einstein-De Sitter Debate, 1916-1918

    NASA Astrophysics Data System (ADS)

    Midwinter, Charles; Janssen, Michel

    2011-03-01

    The Einstein De Sitter debate marked the birth of modern cosmology and the infamous cosmological constant. For Einstein, the controversy was essentially a philosophical one. Einstein's insistence on a static Universe and Mach's Principle guided him in the construction of his own cosmological model, and compelled him to criticize De Sitter's. For De Sitter, the debate began as idle conjecture. Before long, however, he began to wonder if the "spacious castles" he and Einstein had constructed might actually represent physical reality. We plan to write a volume that reproduces the documents relevant to the debate. Our commentary will retrace and explain the arguments of the historical players, complete with calculations. For the first time readers will be able to follow the arguments of Einstein and De Sitter in a detailed exploration of the first two relativistic cosmological models. Readers will see how Einstein's flawed criticisms of De Sitter were supported by Herman Weyl, and finally how Felix Klein settled the whole matter with a coordinate transformation.

  11. Riemann correlator in de Sitter including loop corrections from conformal fields

    SciTech Connect

    Fröb, Markus B.; Verdaguer, Enric

    2014-07-01

    The Riemann correlator with appropriately raised indices characterizes in a gauge-invariant way the quantum metric fluctuations around de Sitter spacetime including loop corrections from matter fields. Specializing to conformal fields and employing a method that selects the de Sitter-invariant vacuum in the Poincaré patch, we obtain the exact result for the Riemann correlator through order H{sup 4}/m{sub p}{sup 4}. The result is expressed in a manifestly de Sitter-invariant form in terms of maximally symmetric bitensors. Its behavior for both short and long distances (sub- and superhorizon scales) is analyzed in detail. Furthermore, by carefully taking the flat-space limit, the explicit result for the Riemann correlator for metric fluctuations around Minkowki spacetime is also obtained. Although the main focus is on free scalar fields (our calculation corresponds then to one-loop order in the matter fields), the result for general conformal field theories is also derived.

  12. Riemann correlator in de Sitter including loop corrections from conformal fields

    NASA Astrophysics Data System (ADS)

    Fröb, Markus B.; Roura, Albert; Verdaguer, Enric

    2014-07-01

    The Riemann correlator with appropriately raised indices characterizes in a gauge-invariant way the quantum metric fluctuations around de Sitter spacetime including loop corrections from matter fields. Specializing to conformal fields and employing a method that selects the de Sitter-invariant vacuum in the Poincaré patch, we obtain the exact result for the Riemann correlator through order H4/mp4. The result is expressed in a manifestly de Sitter-invariant form in terms of maximally symmetric bitensors. Its behavior for both short and long distances (sub- and superhorizon scales) is analyzed in detail. Furthermore, by carefully taking the flat-space limit, the explicit result for the Riemann correlator for metric fluctuations around Minkowki spacetime is also obtained. Although the main focus is on free scalar fields (our calculation corresponds then to one-loop order in the matter fields), the result for general conformal field theories is also derived.

  13. Dark fluid or cosmological constant: Why there are different de Sitter-type spacetimes

    NASA Astrophysics Data System (ADS)

    Nouri-Zonoz, M.; Koohbor, J.; Ramezani-Aval, H.

    2015-03-01

    Many different forms of the de Sitter metric in different coordinate systems are used in the general relativity literature. Two of them are the most common: the static form and the cosmological (exponentially expanding) form. The staticity and nonstationarity of these two different forms are traced back to the noncomoving and comoving nature of the corresponding coordinate systems. In this paper, using the quasi-Maxwell form of the Einstein field equations and a definition of static spacetimes based upon them, we look at these two different forms of the same solution from a new perspective which classifies them as a special case in a general one-parameter family of solutions. Specifically it is proved that, irrespective of the spacetime symmetry, a one-element perfect fluid in any frame noncomoving with the fluid could be the source of a static spacetime, only if its equation of state is that of a dark fluid, namely, p =-ρ =const . These static solutions, which include the well-known de Sitter spacetime, are called de Sitter-type spacetimes. To answer the question posed in the title, we consider static axially and cylindrically symmetric de Sitter-type spacetimes and their dynamic (cosmological) versions. It is shown how despite the seemingly natural expectation based on the presence of Λ as their only parameter, the nonspherical expansions of these genuinely different solutions should be expected indeed. To the best of our knowledge the dynamic version of the cylindrically symmetric de Sitter-type spacetime is introduced here for the first time. Finally it is noted that the identification of the geometric term Λ gi j with a perfect fluid with equation of state p =-ρ =const , although mathematically consistent, obscures the crucial role of the (dark) fluid's velocity in defining a preferred (comoving) coordinate system in de Sitter-type spacetimes.

  14. Fermion production in dipolar electric field on de Sitter expanding universe

    SciTech Connect

    Băloi, Mihaela-Andreea Crucean, Cosmin

    2015-12-07

    The production of fermions in dipolar electric fields on de Sitter universe is studied. The amplitude and probability of pair production are computed using the exact solution of the Dirac equation in de Sitter spacetime. The form of the dipolar fields is established using the conformal invariance of the Maxwell equations. We obtain that the momentum conservation law is broken in the process of pair production in dipolar electric fields. Also we establish that there are nonvanishing probabilities for processes in which the helicity is conserved/nonconserved. The Minkowski limit is recovered when the expansion factor becomes zero.

  15. More on the covariant retarded Green's function for the electromagnetic field in de Sitter spacetime

    SciTech Connect

    Higuchi, Atsushi; Lee, Yen Cheong; Nicholas, Jack R.

    2009-11-15

    In a recent paper 2 it was shown in examples that the covariant retarded Green's functions in certain gauges for electromagnetism and linearized gravity can be used to reproduce field configurations correctly in spite of the spacelike nature of past infinity in de Sitter spacetime. In this paper we extend the work of Ref. 2 concerning the electromagnetic field and show that the covariant retarded Green's function with an arbitrary value of the gauge parameter reproduces the electromagnetic field from two opposite charges at antipodal points of de Sitter spacetime.

  16. Gravitationally induced adiabatic particle production: from big bang to de Sitter

    NASA Astrophysics Data System (ADS)

    de Haro, Jaume; Pan, Supriya

    2016-08-01

    In the background of a flat homogeneous and isotropic space-time, we consider a scenario of the Universe driven by the gravitationally induced ‘adiabatic’ particle production with constant creation rate. We have shown that this Universe attains a big bang singularity in the past and at late-time it asymptotically becomes de Sitter. To clarify this model Universe, we performed a dynamical analysis and found that the Universe attains a thermodynamic equilibrium in this late de Sitter phase. Finally, for the first time, we have discussed the possible effects of ‘adiabatic’ particle creations in the context of loop quantum cosmology.

  17. High-frequency microwave anti-/de-icing system for carbon-reinforced airfoil structures

    NASA Astrophysics Data System (ADS)

    Feher, Lambert; Thumm, Manfred

    2001-08-01

    An aircraft may be subjected to icing for a variety of meteorological reasons during the flight. Ice formation on the plane and in particular on the aerodynamically carrying structures adversely affects the flight behaviour. Conventional de-icing methods for aluminum wings are characterised by a high energy consumption during the flight and slow ice melting due to thermal diffusion of the heat in the wing material. In addition to advanced turbines, novel materials and composites have to be used in order to reduce the weight and, hence, the fuel consumption. These composite materials have a far worse thermal conductivity than metals and undergo delamination when hot air systems, resistance or ohmic heating mats are used. In the paper, the unique advantages of a novel High Frequency Microwave Anti-/De-icing System for large future aircraft with carbon reinforced leading edge structures are presented.

  18. Bulk matters on symmetric and asymmetric de Sitter thick branes

    SciTech Connect

    Liu, Yu-Xiao; Zhao, Zhen-Hua; Wei, Shao-Wen; Duan, Yi-Shi E-mail: zhaozhenhua@impcas.ac.cn E-mail: ysduan@lzu.edu.cn

    2009-02-15

    An asymmetric thick domain wall solution with de Sitter (dS) expansion in five dimensions can be constructed from a symmetric one by using a same scalar (kink) with different potentials. In this paper, by presenting the mass-independent potentials of Kaluza-Klein (KK) modes in the corresponding Schroedinger equations, we investigate the localization and mass spectra of various bulk matter fields on the symmetric and asymmetric dS thick branes. For spin 0 scalars and spin 1 vectors, the potentials of KK modes in the corresponding Schroedinger equations are the modified Poeschl-Teller potentials, and there exist a mass gap and a series of continuous spectrum. It is shown that the spectrum of scalar KK modes on the symmetric dS brane contains only one bound mode (the massless mode). However, for the asymmetric dS brane with a large asymmetric factor, there are two bound scalar KK modes: a zero mode and a massive mode. For spin 1 vectors, the spectra of KK modes on both dS branes consist of a bound massless mode and a set of continuous ones, i.e., the asymmetric factor does not change the number of the bound vector KK modes. For spin 1/2 fermions, two types of kink-fermion couplings are investigated in detail. For the usual Yukawa coupling {eta}barPsi{phi}{Psi}, there exists no mass gap but a continuous gapless spectrum of KK states. For the scalar-fermion coupling {eta}barPsisin({phi}/{phi}{sub 0})cos{sup -{delta}}({phi}/{phi}{sub 0}){Psi} with a positive coupling constant {eta}, there exist some discrete bound KK modes and a series of continuous ones. The total number of bound states increases with the coupling constant {eta}. For the case of the symmetric dS brane and positive {eta}, there are N{sub L}(N{sub L} {>=} 1) left chiral fermion bound states (including zero mode and massive KK modes) and N{sub L}-1 right chiral fermion bound states (including only massive KK modes). For the asymmetric dS brane scenario, the asymmetric factor a reduces the number of the

  19. Duffin-Kemmer-Petiau oscillator with Snyder-de Sitter algebra

    NASA Astrophysics Data System (ADS)

    Falek, M.; Merad, M.; Birkandan, T.

    2017-02-01

    We present an exact solution of the one-dimensional Bosonic oscillator for spin 1 and spin 0 particles with the Snyder-de Sitter model, where the energy eigenvalues and eigenfunctions are determined for both cases. The wave functions can be given in terms of Gegenbauer polynomials. We also comment on the thermodynamic properties of the system.

  20. Interpretational conflicts between the static and non-static forms of the de Sitter metric

    PubMed Central

    Mitra, Abhas

    2012-01-01

    The de-Sitter metric is a special form of the non-static Friedmann metric, and appears to be genuinely non-static since it describes the initial exponential expansion of the Big Bang universe. However, the de Sitter metric appears to be perfectly static in the Schwarzschild frame where the vacuum fluid is supposed to be in motion. Here we highlight the conflicts between the static and non-static versions of the de-Sitter metric from a physical perspective. In particular, while the “Principle of Energy Conservation” is honored in one case, the same is badly violated for the other. However, we offer a partial resolution of such conflicts by deriving the static de Sitter metric by solving the relevant field equations. It is seen that, it is the very special vacuum equation of state pressure = –density which results in the static form even when the vacuum fluid is supposed to be in motion. PMID:23213359

  1. A new method of researching fermion tunneling from the Vaidya-Bonner de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Lin, Kai; Yang, Shu-Zheng

    2009-06-01

    Using the general tortoise coordinate transformation, we research the fermion tunneling of the Vaidya-Bonner de Sitter black hole via a semi-classical method and finally obtain the right surface gravity, Hawking temperature and tunneling rate near the event horizon and cosmical horizon.

  2. The Booth Sitters of Santa Fe's Indian Market: Making and Maintaining Authenticity

    ERIC Educational Resources Information Center

    Bernstein, Bruce

    2007-01-01

    In this article, the author addresses the burden of non-Native expectation on Native artists, highlighting issues of authenticity, creation, and public display. The author writes about the booth sitters hired by collectors to sit--sometimes all night--and wait for the official opening of the annual Indian Market in Santa Fe, New Mexico. He focuses…

  3. Late-time quadrupolar gravitational wave power in de Sitter space

    NASA Astrophysics Data System (ADS)

    Hazboun, Jeffrey

    2017-01-01

    We have calculated the power emitted by a binary system in a cosmological context modeled by a stress energy source on a de Sitter background. The calculation is based on the quadrupole formula for late-time gravitational waves in de Sitter space put forward by Ashtekar, Bonga and Kesavan. There is little reason to expect, a priori, that the projection operator usually used to find the transverse-traceless components of a tensor in asymptotically flat spaces will accurately characterize the physical degrees of freedom in an asymptotically de Sitter spacetime. Instead we use the differential recipe that is true in general, but cumbersome to solve explicitly. The solution presented is based on a conformally transformed version of the quadrupole moment from a Minkowski spacetime for a stable circular binary. A process for calculating the late time power is presented, which coincides with future null infinity. Progress on time dependent results will also be presented. We will discuss the physicality of these results and compare it to other results for gravitational waves in de Sitter space, including recent results on gravitational wave memory.

  4. The Sso7d DNA-binding protein from Sulfolobus solfataricus has ribonuclease activity.

    PubMed

    Shehi, E; Serina, S; Fumagalli, G; Vanoni, M; Consonni, R; Zetta, L; Dehò, G; Tortora, P; Fusi, P

    2001-05-25

    Sso7d is a small, basic, abundant protein from the thermoacidophilic archaeon Sulfolobus solfataricus. Previous research has shown that Sso7d can bind double-stranded DNA without sequence specificity by placing its triple-stranded beta-sheet across the minor groove. We previously found RNase activity both in preparations of Sso7d purified from its natural source and in recombinant, purified protein expressed in Escherichia coli. This paper provides conclusive evidence that supports the assignment of RNase activity to Sso7d, shown by the total absence of activity in the single-point mutants E35L and K12L, despite the preservation of their overall structure under the assay conditions. In keeping with our observation that the residues putatively involved in RNase activity and those playing a role in DNA binding are located on different surfaces of the molecule, the activity was not impaired in the presence of DNA. If a small synthetic RNA was used as a substrate, Sso7d attacked both predicted double- and single-stranded RNA stretches, with no evident preference for specific sequences or individual bases. Apparently, the more readily attacked bonds were those intrinsically more unstable.

  5. Stable de Sitter vacua in four-dimensional supergravity originating from five dimensions

    SciTech Connect

    Oegetbil, O.

    2008-11-15

    The five-dimensional stable de Sitter ground states in N=2 supergravity obtained by gauging SO(1,1) symmetry of the real symmetric scalar manifold (in particular, a generic Jordan family manifold of the vector multiplets) simultaneously with a subgroup R{sub s} of the R-symmetry group descend to four-dimensional de Sitter ground states under certain conditions. First, the holomorphic section in four dimensions has to be chosen carefully by using the symplectic freedom in four dimensions; second, a group contraction is necessary to bring the potential into a desired form. Under these conditions, stable de Sitter vacua can be obtained in dimensionally reduced theories (from 5D to 4D) if the semidirect product of SO(1,1) with R{sup (1,1)} together with a simultaneous R{sub s} is gauged. We review the stable de Sitter vacua in four dimensions found in earlier literature for N=2 Yang-Mills Einstein supergravity with the SO(2,1)xR{sub s} gauge group in a symplectic basis that comes naturally after dimensional reduction. Although this particular gauge group does not descend directly from five dimensions, we show that its contraction does. Hence, two different theories overlap in certain limits. Examples of stable de Sitter vacua are given for the cases: (i) R{sub s}=U(1){sub R}, (ii) R{sub s}=SU(2){sub R}, and (iii) N=2 Yang-Mills/Einstein supergravity theory coupled to a universal hypermultiplet. We conclude with a discussion regarding the extension of our results to supergravity theories with more general homogeneous scalar manifolds.

  6. 29 CFR 1626.12 - Conciliation efforts pursuant to section 7(d) of the Act.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Conciliation efforts pursuant to section 7(d) of the Act. 1626.12 Section 1626.12 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION PROCEDURES-AGE DISCRIMINATION IN EMPLOYMENT ACT § 1626.12 Conciliation efforts pursuant to...

  7. Structural and energetic determinants of thermal stability and hierarchical unfolding pathways of hyperthermophilic proteins, Sac7d and Sso7d.

    PubMed

    Priyakumar, U Deva; Ramakrishna, S; Nagarjuna, K R; Reddy, S Karunakar

    2010-02-04

    Identification of the structural and energetic determinants responsible for enhancing the stability of proteins is crucial. Hyperthermophilic proteins are naturally occurring proteins that exhibit high thermal stability and are good candidates for the investigation and understanding of structure-stability relationships. Sac7d from Sulfolobus acidocaldarius and Sso7d from Sulfolobus solfactaricus are two homologous hyperthermophilic proteins that were shown to be quite stable at high temperatures. Molecular dynamics simulations at the nanosecond time scale at different temperatures were performed to examine the factors affecting their stability. The three-dimensional structures of these proteins were observed to be similar to the experimental structure at 300 and 360 K but were found to undergo denaturation at 500 K. Both proteins exhibit similar unfolding pathways that correlates well with the calculated intermolecular interaction energies. The differential dynamic behaviors of these molecules at different temperatures were examined. Structural and energetic analysis of the contributions of salt bridges indicates a stabilizing effect at higher temperatures. However, the lifetimes of the salt bridges were found to be quite short, and several new salt bridges formed at 500 K supporting previous studies that the desolvation penalty due to the formation of salt bridges decreases at elevated temperatures. Hydrophobic interactions, which decrease with increase in temperature, were also found to be crucial in the stability of these proteins. Overall, the study shows that a balance among the salt bridge interactions, hydrophobic interactions, and solvent properties is primarily responsible for the high thermal stability of this class of proteins.

  8. Gibbons-Hawking effect in the sonic de Sitter space-time of an expanding Bose-Einstein-condensed gas.

    PubMed

    Fedichev, Petr O; Fischer, Uwe R

    2003-12-12

    We propose an experimental scheme to observe the Gibbons-Hawking effect in the acoustic analog of a (1+1)-dimensional de Sitter universe, produced in an expanding, cigar-shaped Bose-Einstein condensate. It is shown that a two-level system created at the center of the trap, an atomic quantum dot interacting with phonons, observes a thermal Bose distribution at the de Sitter temperature.

  9. Late-time structure of the Bunch-Davies de Sitter wavefunction

    SciTech Connect

    Anninos, Dionysios; Freedman, Daniel Z.; Konstantinidis, George; Anous, Tarek E-mail: tanous@mit.edu E-mail: cgcoss@stanford.edu

    2015-11-01

    We examine the late time behavior of the Bunch-Davies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the Bunch-Davies wavefunction. We consider self-interacting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The four-dimensional Fefferman-Graham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunction contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory.

  10. Gravitational deflection of light in the Schwarzschild-de Sitter space-time

    SciTech Connect

    Bhadra, Arunava; Biswas, Swarnadeep; Sarkar, Kabita

    2010-09-15

    Recent studies suggest that the cosmological constant affects the gravitational bending of photons, although the orbital equation for light in Schwarzschild-de Sitter space-time is free from a cosmological constant. Here we argue that the very notion of a cosmological constant independent of the photon orbit in the Schwarzschild-de Sitter space-time is not proper. Consequently, the cosmological constant has some clear contributions to the deflection angle of light rays. We stress the importance of the study of photon trajectories from the reference objects in bending calculations, particularly for asymptotically nonflat space-time. When such an aspect is taken into consideration, the contribution of a cosmological constant to the effective bending is found to depend on the distances of the source and the reference objects.

  11. Quantum Kalb-Ramond Field in D-Dimensional de Sitter Space-Times

    NASA Astrophysics Data System (ADS)

    Alencar, G.; Guedes, I.; Landim, R. R.; Costa Filho, R. N.

    2013-03-01

    In this work, we investigate the quantum theory of the Kalb-Ramond fields propagating in D-dimensional de Sitter space-times using the dynamic invariant method developed by Lewis and Riesenfeld [J. Math. Phys.10, 1458 (1969)] to obtain the solution of the time-dependent Schrödinger equation. The wave function is written in terms of a c-number quantity satisfying the Milne-Pinney equation, whose solution can be expressed in terms of two independent solutions of the respective equation of motion. We obtain the exact solution for the quantum Kalb-Ramond field in the de Sitter background and discuss its relation with the Cremmer-Scherk-Kalb-Ramond model.

  12. Restoration of the covariant gauge α in the initial field of gravity in de Sitter spacetime

    SciTech Connect

    Cheong, Lee Yen; Yan, Chew Xiao

    2014-03-05

    The gravitational field generated by a mass term and the initial surface through covariant retarded Green's function for linearized gravity in de Sitter spacetime was studied recently [4, 5] with the covariant gauges set to β = 2/3 and α = 5/3. In this paper we extend the work to restore the gauge parameter α in the field coming from the initial data using the method of shifting the parameter. The α terms in the initial field cancels exactly with the one coming from the source term. Consequently, the correct field configuration, with two equal mass points moving in its geodesic, one located at the North pole and another one located at the South pole, is reproduced in the whole manifold of de Sitter spacetime.

  13. Isometry generators in momentum representation of the Dirac theory on the de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Cotăescu, Ion I.; Băltăţeanu, Doru-Marcel

    2015-11-01

    In this paper, it is shown that the covariant representation (CR) transforming the Dirac field under de Sitter isometries is equivalent to a direct sum of two unitary irreducible representations (UIRs) of the Sp(2, 2) group transforming alike the particle and antiparticle field operators in momentum representation. Their basis generators and Casimir operators are written down for the first time finding that these representations are equivalent to an UIR from the principal series whose canonical labels are determined by the fermion mass and spin. The properties of the conserved observables (i.e. one-particle operators) associated to the de Sitter isometries via Noether theorem and of the corresponding Pauli-Lubanski type operator are also pointed out.

  14. Rain, Hail, and Drip frames of the Schwarzschild-de Sitter Geometry

    NASA Astrophysics Data System (ADS)

    Finch, Tehani

    2017-01-01

    Various families of coordinate systems associated with observers moving inwardly along radial geodesics in the Schwarzschild geometry have been constructed by generalizing the Painleve-Gullstrand coordinates. Such observers have categorized as being in the rain frame, a hail frame, or a drip frame, by Taylor and Wheeler. This framework naturally progresses into a search for counterparts of these coordinate systems for the Schwarzschild-de Sitter (SdS) geometry. Consideration of local measurements made by a fiducial observer suggests that the conserved Killing quantity which best fits the designation of ``energy'' in the SdS geometry differs from the one which is typically denoted as such. This leads to Painleve-Gullstrand-style coordinate systems for the SdS geometry that differ from the naïve extrapolations of the Schwarzschild or de Sitter geometries.

  15. Evidence for a bound on the lifetime of de Sitter space

    NASA Astrophysics Data System (ADS)

    Freivogel, Ben; Lippert, Matthew

    2008-12-01

    Recent work has suggested a surprising new upper bound on the lifetime of de Sitter vacua in string theory. The bound is parametrically longer than the Hubble time but parametrically shorter than the recurrence time. We investigate whether the bound is satisfied in a particular class of de Sitter solutions, the KKLT vacua. Despite the freedom to make the supersymmetry breaking scale exponentially small, which naively would lead to extremely stable vacua, we find that the lifetime is always less than about exp(1022) Hubble times, in agreement with the proposed bound. This result, however, is contingent on several estimates and assumptions; in particular, we rely on a conjectural upper bound on the Euler number of the Calabi-Yau fourfolds used in KKLT compactifications.

  16. Late-time structure of the Bunch-Davies de Sitter wavefunction

    SciTech Connect

    Anninos, Dionysios; Anous, Tarek; Freedman, Daniel Z.; Konstantinidis, George

    2015-11-30

    We examine the late time behavior of the Bunch-Davies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the Bunch-Davies wavefunction. We consider self-interacting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The four-dimensional Fefferman-Graham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunction contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory.

  17. Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole

    SciTech Connect

    Myung, Yun Soo

    2008-05-15

    We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization.

  18. Quantum nonthermal effect of the Vaidya-Bonner-de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Pan, Wei-Zhen; Yang, Xue-Jun; Yu, Guo-Xiang

    2014-02-01

    Using the Hamilton-Jacobi equation of a scalar particle in the curve space-time and a correct-dimension new tortoise coordinate transformation, the quantum nonthermal radiation of the Vaidya-Bonner-de Sitter black hole is investigated. The energy condition for the occurrence of the Starobinsky-Unruh process is obtained. The event horizon surface gravity and the Hawking temperature on the event horizon are also given.

  19. Quantum Radiation of a Non-stationary Kerr Newman Black Hole in de Sitter Space Time

    NASA Astrophysics Data System (ADS)

    Jiang, Qing-Quan; Yang, Shu-Zheng

    2006-12-01

    Hawking radiation of Klein-Gordon and Dirac particles in a non-stationary Kerr-Newman-de-Sitter black hole is studied by introducing a new tortoise coordinate transformation. The result shows that the Fermi-Dirac radiant spectrum displays a new term that represents the interaction between the spin of spinor particles and the rotation of black holes, which is absent in the Bose-Einstein distribution of Klein-Gordon particles.

  20. Point splitting renormalization of Schwinger induced current in de Sitter spacetime

    SciTech Connect

    Hayashinaka, Takahiro; Yokoyama, Jun’ichi

    2016-07-08

    The covariant and gauge invariant calculation of the current expectation value in the homogeneous electric field in 1+3 dimensional de Sitter spacetime is shown. The result accords with previous work obtained by using adiabatic subtraction scheme. We therefore conclude the counterintuitive behaviors of the current in the infrared (IR) regime such as IR hyperconductivity and negative current are not artifacts of the renormalization scheme, but are real IR effects of the spacetime.

  1. On the covariant gauge {alpha} of the linearized gravity in de Sitter spacetime

    SciTech Connect

    Cheong, Lee Yen

    2012-09-26

    In previous work, we studied the linearized gravity with covariant gauge {beta}= 2/3 and {alpha}= 5/3. It was found that the sum of the source and initial contributions reproduces the correct field configuration over the whole de Sitter spacetime. In this paper, we extend this work to generalizing the linearized gravitational field in an arbitrary value of the gauge parameter {alpha} but the gauge parameter {beta} remains the same.

  2. Reduce phase space quantization of Ashtekar's gravity on de Sitter background

    SciTech Connect

    I. Grigentch; D.V. Vassilevich

    1994-05-01

    The authors solve perturbative constraints and eliminate gauge freedom for Ashtekar's gravity on de Sitter background. They show that the reduced phase space consists of transverse, traceless, symmetric, fluctuations of the triad and of transverse, traceless, symmetric fluctuations of the connection. A part of gauge freedom corresponding to the conformal Killing vectors of the three-manifold can be fixed only by imposing conditions on Lagrange multiplier. The reduced phase space is equivalent to that of ADM gravity on the same background.

  3. Separability and Killing tensors in Kerr Taub-NUT de Sitter metrics in higher dimensions

    NASA Astrophysics Data System (ADS)

    Chong, Z.-W.; Gibbons, G. W.; Lü, H.; Pope, C. N.

    2005-03-01

    A generalisation of the four-dimensional Kerr-de Sitter metrics to include a NUT charge is well known, and is included within a class of metrics obtained by Plebanski. In this Letter, we study a related class of Kerr-Taub-NUT-de Sitter metrics in arbitrary dimensions D ⩾ 6, which contain three non-trivial continuous parameters, namely the mass, the NUT charge, and a (single) angular momentum. We demonstrate the separability of the Hamilton-Jacobi and wave equations, we construct a closely-related rank-2 Stäckel-Killing tensor, and we show how the metrics can be written in a double Kerr-Schild form. Our results encompass the case of the Kerr-de Sitter metrics in arbitrary dimension, with all but one rotation parameter vanishing. Finally, we consider the real Euclidean-signature continuations of the metrics, and show how in a limit they give rise to certain recently-obtained complete non-singular compact Einstein manifolds.

  4. A preferred ground state for the scalar field in de Sitter space

    NASA Astrophysics Data System (ADS)

    Aslanbeigi, S.; Buck, M.

    2013-08-01

    We investigate a recent proposal for a distinguished vacuum state of a free scalar quantum field in an arbitrarily curved spacetime, known as the Sorkin-Johnston (SJ) vacuum, by applying it to de Sitter space. We derive the associated two-point functions on both the global and Poincaré (cosmological) patches in general d + 1 dimensions. In all cases where it is defined, the SJ vacuum belongs to the family of de Sitter invariant α-vacua. We obtain different states depending on the spacetime dimension, mass of the scalar field, and whether the state is evaluated on the global or Poincaré patch. We find that the SJ vacuum agrees with the Euclidean/Bunch-Davies state for heavy ("principal series") fields on the global patch in even spacetime dimensions. We also compute the SJ vacuum on a causal set corresponding to a causal diamond in 1 + 1 dimensional de Sitter space. Our simulations show that the mean of the SJ two-point function on the causal set agrees well with its expected continuum counterpart.

  5. Dynamics and quantum entanglement of two-level atoms in de Sitter spacetime

    SciTech Connect

    Tian, Zehua; Jing, Jiliang

    2014-11-15

    In the framework of open quantum systems, we study the internal dynamics of both freely falling and static two-level atoms interacting with quantized conformally coupled massless scalar field in de Sitter spacetime. We find that the atomic transition rates depend on both the nature of de Sitter spacetime and the motion of atoms, interestingly the steady states for both cases are always driven to being purely thermal, regardless of the atomic initial states. This thermalization phenomenon is structurally similar to what happens to an elementary quantum system immersed in a thermal field, and thus reveals the thermal nature of de Sitter spacetime. Besides, we find that the thermal baths will drive the entanglement shared by the freely falling atom (the static atom) and its auxiliary partner, a same two-level atom which is isolated from external fields, to being sudden death, and the proper time for the entanglement to be extinguished is computed. We also analyze that such thermalization and disentanglement phenomena, in principle, could be understood from the perspective of table-top simulation experiment.

  6. Huygens' principle for the Klein-Gordon equation in the de Sitter spacetime

    SciTech Connect

    Yagdjian, Karen

    2013-09-15

    In this article we prove that the Klein-Gordon equation in the de Sitter spacetime obeys the Huygens' principle only if the physical mass m of the scalar field and the dimension n⩾ 2 of the spatial variable are tied by the equation m{sup 2}= (n{sup 2}−1)/4. Moreover, we define the incomplete Huygens' principle, which is the Huygens' principle restricted to the vanishing second initial datum, and then reveals that the massless scalar field in the de Sitter spacetime obeys the incomplete Huygens' principle and does not obey the Huygens' principle, for the dimensions n= 1, 3, only. Thus, in the de Sitter spacetime the existence of two different scalar fields (in fact, with m= 0 and m{sup 2}= (n{sup 2}−1)/4), which obey incomplete Huygens' principle, is equivalent to the condition n= 3, the spatial dimension of the physical world. In fact, Paul Ehrenfest in 1917 addressed the question: “Why has our space just three dimensions?”. For n= 3 these two values of the mass are the endpoints of the so-called in quantum field theory the Higuchi bound. The value m{sup 2}= (n{sup 2}−1)/4 of the physical mass allows us also to obtain complete asymptotic expansion of the solution for the large time.

  7. Detecting the Curvature of de Sitter Universe with Two Entangled Atoms

    PubMed Central

    Tian, Zehua; Wang, Jieci; Jing, Jiliang; Dragan, Andrzej

    2016-01-01

    Casimir-Polder interaction arises from the vacuum fluctuations of quantum field that depend on spacetime curvature and thus is spacetime-dependent. Here we show how to use the resonance Casimir-Polder interaction (RCPI) between two entangled atoms to detect spacetime curvature. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature relevant to the temperature felt by the static observer. It is characterized by a 1/L2 power law decay when beyond a characteristic length scale associated to the breakdown of a local inertial description of the two-atom system. However, the RCPI of the same setup embedded in a thermal bath in the Minkowski universe is temperature-independent and is always characterized by a 1/L power law decay. Therefore, although a single static atom in the de Sitter-invariant vacuum responds as if it were bathed in thermal radiation in a Minkowski universe, using the distinct difference between RCPI of two entangled atoms one can in principle distinguish these two universes. PMID:27731419

  8. Detecting the Curvature of de Sitter Universe with Two Entangled Atoms.

    PubMed

    Tian, Zehua; Wang, Jieci; Jing, Jiliang; Dragan, Andrzej

    2016-10-12

    Casimir-Polder interaction arises from the vacuum fluctuations of quantum field that depend on spacetime curvature and thus is spacetime-dependent. Here we show how to use the resonance Casimir-Polder interaction (RCPI) between two entangled atoms to detect spacetime curvature. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature relevant to the temperature felt by the static observer. It is characterized by a 1/L(2) power law decay when beyond a characteristic length scale associated to the breakdown of a local inertial description of the two-atom system. However, the RCPI of the same setup embedded in a thermal bath in the Minkowski universe is temperature-independent and is always characterized by a 1/L power law decay. Therefore, although a single static atom in the de Sitter-invariant vacuum responds as if it were bathed in thermal radiation in a Minkowski universe, using the distinct difference between RCPI of two entangled atoms one can in principle distinguish these two universes.

  9. Axial and polar gravitational wave equations in a de Sitter expanding universe by Laplace transform

    NASA Astrophysics Data System (ADS)

    Viaggiu, Stefano

    2017-02-01

    In this paper we study the propagation in a de Sitter universe of gravitational waves generated by perturbating some unspecified spherical astrophysical object in the frequencies domain. We obtain the axial and polar perturbation equations in a cosmological de Sitter universe in the usual comoving coordinates, the coordinates we occupy in our galaxy. We write down the relevant equations in terms of Laplace transform with respect to the comoving time t instead of the usual Fourier one that is no longer available in a cosmological context. Both axial and polar perturbation equations are expressed in terms of a non trivial mixture of retarded-advanced metric coefficients with respect to the Laplace parameter s (complex translation). The axial case is studied in more detail. In particular, the axial perturbations can be reduced to a master linear second-order differential equation in terms of the Regge–Wheeler function Z where a coupling with a retarded Z with respect to the cosmological time t is present. It is shown that a de Sitter expanding universe can change the frequency ω of a gravitational wave as perceived by a comoving observer. The polar equations are much more involved. Nevertheless, we show that the polar perturbations can also be expressed in terms of four independent integrable differential equations.

  10. Detecting the Curvature of de Sitter Universe with Two Entangled Atoms

    NASA Astrophysics Data System (ADS)

    Tian, Zehua; Wang, Jieci; Jing, Jiliang; Dragan, Andrzej

    2016-10-01

    Casimir-Polder interaction arises from the vacuum fluctuations of quantum field that depend on spacetime curvature and thus is spacetime-dependent. Here we show how to use the resonance Casimir-Polder interaction (RCPI) between two entangled atoms to detect spacetime curvature. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature relevant to the temperature felt by the static observer. It is characterized by a 1/L2 power law decay when beyond a characteristic length scale associated to the breakdown of a local inertial description of the two-atom system. However, the RCPI of the same setup embedded in a thermal bath in the Minkowski universe is temperature-independent and is always characterized by a 1/L power law decay. Therefore, although a single static atom in the de Sitter-invariant vacuum responds as if it were bathed in thermal radiation in a Minkowski universe, using the distinct difference between RCPI of two entangled atoms one can in principle distinguish these two universes.

  11. Regulation of PBX3 expression by androgen and Let-7d in prostate cancer

    PubMed Central

    2011-01-01

    Background The pre-leukemia transcription factor 3 (PBX) is part of the PBX family of transcription factors, which is known to regulate genes involved in differentiation of urogenital organs and steroidogenesis. This is of interest with regard to prostate cancer progression as regulation of steroidogenesis is one of the mechanisms involved in the development of castration-resistant prostate cancer. In light of this we wanted to investigate the possible involvement of androgen regulation of PBX3 expression in prostate cancer. Results In this study, we show that PBX3 is post-transcriptionally regulated by androgen in prostate cancer cells and that the effect might be independent of the androgen receptor. Furthermore, PBX3 was identified as a target of Let-7d, an androgen regulated microRNA. Let-7d was down-regulated in malignant compared to benign prostate tissue, whereas up-regulation of PBX3 expression was observed. Conclusions We demonstrate that PBX3 is up-regulated in prostate cancer and post- transcriptionally regulated by androgen through Let-7d. PMID:21548940

  12. Dingle and de Sitter Against the Metaphysicians, or Two Ways to Keep Modern Cosmology Physical

    NASA Astrophysics Data System (ADS)

    Gale, George

    It would be hard to find two more radically different personalities than the irascible Herbert Dingle and the courtly Willem de Sitter. Yet, when it came to their philosophy of science, these two otherwise-so-different men were united against a common enemy, those they both called the "metaphysicians." Right from 1917, de Sitter attempted always to keep cosmology tightly bound to real observations made upon a real world. In Kosmos, written near the end of his life, he re-affirms most strongly his principle that "there is nothing an orthodox physicist abhors more than metaphysics." Dingle, for his part, accepts early on the positivist use of the verifiability principle to eliminate metaphysics from science, and continuously wields the principle as a weapon against those errant cosmologists who would sacrifice science for a sort of mysticism. Both men reject the strict and literal use of the term "universe," and for the same reasons: there is no observation, no verification, of statements containing that term. Both men reject the "cosmological principle" as Milne and others use it, on the grounds, as de Sitter puts it, that "we have . . . no means of communicating with other observers, situated on faraway stars." Eddington, although always closely associated with de Sitter personally, comes in for his own fine share of criticism. After de Sitter's death, Dingle carried on the battle alone, always on the bases that he and de Sitter had earlier established. The two peaks in Dingle's long struggle were the notorious 1937 controversy in the pages of Nature, a nasty dogfight which managed to involve almost every single important physicist in Britain; thirteen years later, the long war with the metaphysicians ended with the pyrrhic victory of Dingle's Royal Astronomical Society Presidential Address' invective against the latest and greatest metaphysical creation, Bondi's steady state universe theory. In the end, however, it would be a mistake to believe that the campaign

  13. Hawking-de Sitter Thermalization of Quasi-Minkowskian Massless Scalaron Production, Energy Density Content and Back-Reaction

    NASA Astrophysics Data System (ADS)

    Pîrghie, Ana-Camelia; Dariescu, Ciprian; Dariescu, Marina-Aura

    2010-01-01

    Projecting the closed form expression of the de Sitter scalar field operator onto the Minkowskian positive frequency massless modes, we compute the corresponding Bogolubov coefficient which is associated to the (massless) quasiparticle creation during the stationary quasi-de Sitter stage of the Universe. Thereafter, we derive the expression of the thermalized energy density which reveals an interesting mixture of de Sitter false vacuum and dark-radiation, exotic dust and black body radiation. Setting the temperature to the value of the Hawking one for the de Sitter spacetime, we finally analyze the (straightforward) back-reaction of the newly created “matter” on the scale function. It basically points out three stages of highly continuous evolution represented by an initially short radiation-like era, a somewhat long-lasting connecting phase made of coherent massless oscillations, in its beginnings, ended up by the dark-radiation (i.e. curvature-like term) contribution and, finally, a much slower exponential expansion than the initial de Sitter one.

  14. The acid-induced folded state of Sac7d is the native state.

    PubMed Central

    Bedell, J. L.; McCrary, B. S.; Edmondson, S. P.; Shriver, J. W.

    2000-01-01

    Sac7d unfolds at low pH in the absence of salt, with the greatest extent of unfolding obtained at pH 2. We have previously shown that the acid unfolded protein is induced to refold by decreasing the pH to 0 or by addition of salt (McCrary BS, Bedell J. Edmondson SP, Shriver JW, 1998, J Mol Biol 276:203-224). Both near-ultraviolet circular dichroism spectra and ANS fluorescence enhancements indicate that the acid- and salt-induced folded states have a native fold and are not molten globular. 1H,15N heteronuclear single quantum coherence NMR spectra confirm that the native, acid-, and salt-induced folded states are essentially identical. The most significant differences in amide 1H and 15N chemical shifts are attributed to hydrogen bonding to titrating carboxyl side chains and through-bond inductive effects. The 1H NMR chemical shifts of protons affected by ring currents in the hydrophobic core of the acid- and salt-induced folded states are identical to those observed in the native. The radius of gyration of the acid-induced folded state at pH 0 is shown to be identical to that of the native state at pH 7 by small angle X-ray scattering. We conclude that acid-induced collapse of Sac7d does not lead to a molten globule but proceeds directly to the native state. The folding of Sac7d as a function of pH and anion concentration is summarized with a phase diagram that is similar to those observed for other proteins that undergo acid-induced folding except that the A-state is encompassed by the native state. These results demonstrate that formation of a molten globule is not a general property of proteins that are refolded by acid. PMID:11106160

  15. In vitro DNA binding of the archaeal protein Sso7d induces negative supercoiling at temperatures typical for thermophilic growth.

    PubMed Central

    López-García, P; Knapp, S; Ladenstein, R; Forterre, P

    1998-01-01

    The topological state of DNA in hyperthermophilic archaea appears to correspond to a linking excess in comparison with DNA in mesophilic organisms. Since DNA binding proteins often contribute to the control of DNA topology by affecting DNA geometry in the presence of DNA topoisomerases, we tested whether the histone-like protein Sso7d from the hyperthermophilic archaeon Sulfolobus solfataricus alters DNA conformation. In ligase-mediated supercoiling assays carried out at 37, 60, 70, 80 and 90 degrees C we found that DNA binding of increasing amounts of Sso7d led to a progressive decrease in plasmid linking number (Lk), producing negative supercoiling. Identical unwinding effects were observed when recombinant non-methylated Sso7d was used. For a given Sso7d concentration the DNA unwinding induced was augmented with increasing temperature. However, after correction for the overwinding effect of high temperature on DNA, plasmids ligated at 60-90 degrees C exhibited similar sigma values at the highest Sso7d concentrations assayed. These results suggest that Sso7d may play a compensatory role in vivo by counteracting the overwinding effect of high temperature on DNA. Additionally, Sso7d unwinding could be involved in the topological changes observed during thermal stress (heat and cold shock), playing an analogous role in crenarchaeal cells to that proposed for HU in bacteria. PMID:9580681

  16. Perturbative Quantum Gravity and Yang-Mills Theories in de Sitter Spacetime

    NASA Astrophysics Data System (ADS)

    Faizal, Mir

    2011-05-01

    This thesis consists of three parts. In the first part we review the quantization of Yang-Mills theories and perturbative quantum gravity in curved spacetime. In the second part we calculate the Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge. In the third part we investigate the physical equivalence of covariant Wightman graviton two-point function with the physical graviton two-point function. The Feynman propagators of the Faddeev-Popov ghosts for Yang-Mills theories and perturbative quantum gravity in the covariant gauge are infrared (IR) divergent in de Sitter spacetime. We point out, that if we regularize these divergences by introducing a finite mass and take the zero mass limit at the end, then the modes responsible for these divergences will not contribute to loop diagrams in computations of time-ordered products in either Yang-Mills theories or perturbative quantum gravity. We thus find effective Feynman propagators for ghosts in Yang-Mills theories and perturbative quantum gravity by subtracting out these divergent modes. It is known that the covariant graviton two-point function in de Sitter spacetime is infrared divergent for some choices of gauge parameters. On the other hand it is also known that there are no infrared problems for the physical graviton two-point function obtained by fixing all gauge degrees of freedom, in global coordinates. We show that the covariant Wightman graviton two-point function is equivalent to the physical one in the sense that they result in the same two-point function of any local gauge-invariant quantity. Thus any infrared divergence in the Wightman graviton two-point function in de Sitter spacetime can only be an gauge artefact.

  17. Thermodynamic analysis of universes with the initial and final de Sitter eras

    NASA Astrophysics Data System (ADS)

    Moradpour, H.; Sabet, M. T. Mohammadi; Ghasemi, A.

    2015-08-01

    Our aim is studying the thermodynamics of cosmological models including initial and final de Sitter eras. For this propose, bearing Cai-Kim temperature in mind, we investigate the thermodynamic properties of a dark energy (DE) candidate with variable energy density, and show that the state parameter of this dark energy candidate (ωD) should obey the ωD≠ - 1 constraint, whiles there is no interaction between the fluids filled the universe, and the universe is not in the de Sitter eras. Additionally, based on the thermal fluctuation theory, we study the possibility of inducing fluctuations to the entropy of the DE candidate due to a mutual interaction between the cosmos sectors. Therefore, we find a relation between the thermal fluctuations and the mutual interaction between the cosmos sectors, whiles the DE candidate has a varying energy density. Finally, bearing the coincidence problem in mind, we derive a constraint on the vacuum energy, and investigate its relation with the entropy evolution of the DE candidate. We also point to a model with initial and final de Sitter eras in which a gravitationally induced particle production process leads to change the expansion eras, whiles the corresponding pressure is considered as the cause of current accelerated phase. We study its thermodynamics, and show that such processes may also leave thermal fluctuations into the system. We also find an expression between the thermal fluctuations and the particle production rate. Finally, we use Hayward-Kodama temperature to get a relation for the horizon entropy in models including the gravitationally induced particle production process. Our study shows that the first law of thermodynamics is available on the apparent horizon whiles, the gravitationally induced particle production process, as the DE candidate, may add an additional term to the Bekenstein limit of the horizon. The relation between the validity of the second law of thermodynamics and the gravitationally particle

  18. Reissner—Nordström-de—Sitter-type Solution by a Gauge Theory of Gravity

    NASA Astrophysics Data System (ADS)

    Enache, V.; Camelia, Popa; Păun, V.; Agop, M.

    2008-10-01

    We use the theory based on a gravitational gauge group (Wu's model) to obtain a spherical symmetric solution of the Geld equations for the gravitational potential on a Minkowski spacetime. The gauge group, the gauge covariant derivative, the strength tensor of the gauge Held, the gauge invariant Lagrangean with the cosmological constant, the Geld equations of the gauge potentials with a gravitational energy-momentum tensor as well as with a tensor of the Geld of a point like source are determined. Finally, a Reissner-Nordstrom-de Sitter-type metric on the gauge group space is obtained.

  19. Exact gravitational lensing in conformal gravity and Schwarzschild-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Lim, Yen-Kheng; Wang, Qing-hai

    2017-01-01

    An exact solution is obtained for the gravitational bending of light in static, spherically symmetric metrics which includes the Schwarzschild-de Sitter spacetime and also the Mannheim-Kazanas metric of conformal Weyl gravity. From the exact solution, we obtain a small-bending-angle approximation for a lens system where the source, lens, and observer are coaligned. This expansion improves previous calculations where we systematically avoid parameter ranges that correspond to nonexistent null trajectories. The linear coefficient γ characteristic to conformal gravity is shown to contribute enhanced deflection compared to the angle predicted by general relativity for small γ .

  20. Comment on "Fermion production in a magnetic field in a de Sitter universe"

    NASA Astrophysics Data System (ADS)

    Nicolaevici, Nistor; Farkas, Attila

    2017-02-01

    We point out that the transition probabilities used in a recent perturbative calculation of pair creation in an external magnetic field in the expanding de Sitter space with the in and out fermion states defined by the Bunch-Davies modes [C. Crucean and M. A. Baloi, Phys. Rev. D 93, 044070 (2016), 10.1103/PhysRevD.93.044070] are gauge-dependent quantities. We examine the gauge variations of these amplitudes assuming a decoupling of the interaction at infinite times, which allows us to conclude that the source of the problem lies in the nonoscillatory behavior of the fermion current in the infinite future.

  1. New tortoise coordinate transformation and Hawking's radiation in de Sitter space

    NASA Astrophysics Data System (ADS)

    Ibohal, N.; Ibungochouba, T.

    2013-01-01

    Hawking's radiation effect of Klein-Gordon equation, Dirac particles and Maxwell's electromagnetic fields in the non-stationary rotating de Sitter cosmological space-time is investigated by using a new method of generalized tortoise coordinate transformation. It is found that the new transformation produces constant additional terms in the expressions of the surface gravities and the Hawking's temperatures. If the constant terms are set to zero, then the surface gravities and Hawking's temperatures will be equal to those obtained from the old generalized tortoise coordinate transformations. This shows that the new transformations are more reasonable. The Fermionic spectrum of Dirac particles displays a new spin-rotation coupling effect.

  2. Hawking radiation of a Reissner-Nordström-de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Zhao, Ren; Zhang, Li-Chun; Li, Huai-Fan

    2010-04-01

    Generalizing the method proposed by Damour-Ruffini, we discuss Hawking radiation of a Reissner-Nordström-de Sitter (RNdS) black hole. Under the condition that total energy and charge are conserved, taking the reaction of the radiation of particles to the spacetime into consideration and considering the interrelation between the event horizon and cosmological horizon, we investigate radiation spectrum of RNdS spacetime by a new Tortoise coordinate transformation. This radiation spectrum is no longer a purely thermal spectrum. It is related to the changes in the Bekenstein-Hawking entropy corresponding the event horizon and cosmological horizon. The result satisfies the unitary principle.

  3. Spinor Field at the Phase Transition Point of Reissner-Nordström de Sitter Space

    NASA Astrophysics Data System (ADS)

    Lyu, Yan; Zhang, Li-Qing; Zheng, Wei; Pan, Qing-Chao

    2010-08-01

    The radial parts of Dirac equation between the outer black hole horizon and the cosmological horizon are solved in Reissner-Nordström de Sitter (RNdS) space when it is at the phase transition point. We use an accurate polynomial approximation to approximate the modified tortoise coordinate hat{r}_{*} in order to get the inverse function r=r(hat{r}_{*}) and the potential V(hat{r}_{*}). Then we use a quantum mechanical method to solve the wave equation numerically. We consider two cases, one is when the two horizons are lying close to each other, the other is when the two horizons are widely separated.

  4. Real scalar field scattering in the nearly extremal Schwarzschild—de Sitter space

    NASA Astrophysics Data System (ADS)

    Guo, Guang-Hai

    2010-11-01

    Reasonable approximations are introduced to investigate the real scalar field scattering in the nearly extremal Schwarzschild—de Sitter (SdS) space. The approximations naturally lead to the invertible x(r) and the global replacement of the true potential by a Pöshl—Teller one. Meanwhile, the Schrödinger-like wave equation is transformed into a solvable form. Our numerical solutions to the wave equation show that the wave is characteristically similar to the harmonic under the tortoise coordinate x, while the wave piles up near the two horizons and the wavelength tends to its maximum as the potential approaches to the peak under the radial coordinate r.

  5. Solution of Dirac equation in Reissner-Nordström de Sitter space

    NASA Astrophysics Data System (ADS)

    Lyu, Yan; Cui, Song

    2009-02-01

    The radial parts of the Dirac equation between the outer black hole horizon and the cosmological horizon are solved in Reissner-Nordström de Sitter (RNdS) space numerically. An accurate approximation, the polynomial approximation, is used to approximate the modified tortoise coordinate \\hat r_* , which leads to the inverse function r = r(\\hat r_* ) and the potential V(\\hat r_* ). The potential V(\\hat r_* ) is replaced by a collection of step functions in sequence. Then the solution of the wave equation as well as the reflection and transmission coefficients is computed by a quantum mechanical method.

  6. On Fayet-Iliopoulos Terms and de Sitter Vacua in Supergravity: Some Easy Pieces

    SciTech Connect

    Catino, Francesca; Villadoro, Giovanni; Zwirner, Fabio; /Padua U. /INFN, Padua

    2012-03-27

    We clarify a number of issues on Fayet-Iliopoulos (FI) terms in supergravity, keeping the formalism at a minimum and making use of explicit examples. We explain why, if the U(1) vector is massive everywhere in field space, FI terms are not genuine and can always be redefined away or introduced when they are not present. We formulate a simple anomaly-free model with a genuine FI term, a classically stable de Sitter (dS) vacuum and no global symmetries. We explore the relation between N = 2 and N = 1 FI terms by discussing N = 1 truncations of N = 2 models with classically stable dS vacua.

  7. The algebra of supertraces for 2+1 super de Sitter gravity

    NASA Technical Reports Server (NTRS)

    Urrutia, L. F.; Waelbroeck, H.; Zertuche, F.

    1993-01-01

    The algebra of the observables for 2+1 super de Sitter gravity, for one genus of the spatial surface is calculated. The algebra turns out to be an infinite Lie algebra subject to non-linear constraints. The constraints are solved explicitly in terms of five independent complex supertraces. These variables are the true degrees of freedom of the system and their quantized algebra generates a new structure which is referred to as a 'central extension' of the quantum algebra SU(2)q.

  8. Cosmology in Scalar-Tensor Theory and Asymptotically de Sitter Universe

    NASA Astrophysics Data System (ADS)

    Sen, A. A.; Sen, S.

    We have investigated the cosmological scenarios with a four-dimensional effective action which is connected with multidimensional, supergravity and string theories. The solution for the scale factor is such that initially universe undergoes a decelerated expansion but in late times it enters into the accelerated expansion phase. In fact, it asymptotically becomes a de Sitter universe. The dilaton field in our model is a decreasing function of time and it becomes a constant in late time resulting the exit from the scalar-tensor theory to the standard Einstein's gravity. Also the dilaton field results in the existence of a positive cosmological constant in late times.

  9. Entropy of Reissner-Nordström-de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Chun; Zhao, Ren; Ma, Meng-Sen

    2016-10-01

    Based on the consideration that the black hole horizon and the cosmological horizon of Reissner-Nordström black hole in de Sitter space are not independent each other, we conjecture the total entropy of the system should have an extra term contributed from the entanglement between the two horizons, except for the sum of the two horizon entropies. Making use of the globally effective first law and the effective thermodynamic quantities, we derive the total entropy and find that it will diverge as the two horizons tend to coincide.

  10. Attracted to de Sitter II: cosmology of the shift-symmetric Horndeski models

    SciTech Connect

    Martín-Moruno, Prado; Nunes, Nelson J. E-mail: njnunes@fc.ul.pt

    2015-09-01

    Horndeski models with a de Sitter critical point for any kind of material content may provide a mechanism to alleviate the cosmological constant problem. Moreover, they could allow us to understand the current accelerated expansion of the universe as the result of the dynamical approach to the critical point when it is an attractor. We show that this critical point is indeed an attractor for the shift-symmetric subfamily of models with these characteristics. We study the cosmological scenario that results when considering radiation and matter content, and conclude that their background dynamics is compatible with the latest observational data.

  11. Symmetron and de Sitter attractor in a teleparallel model of cosmology

    NASA Astrophysics Data System (ADS)

    Mohseni Sadjadi, H.

    2017-01-01

    In the teleparallel framework of cosmology, a quintessence with non-minimal couplings to the scalar torsion and a boundary term is considered. A conformal coupling to matter density is also taken into account. It is shown that the model can describe onset of cosmic acceleration after an epoch of matter dominated era, where dark energy is negligible, via Z2 symmetry breaking. While the conformal coupling holds the Universe in a state with zero dark energy density in the early epoch, the non-minimal couplings lead the Universe to a stable state with de Sitter expansion at late time.

  12. Measurement of the de Sitter precession of the moon - A relativistic three-body effect

    NASA Technical Reports Server (NTRS)

    Shapiro, I. I.; Reasenberg, R. D.; Chandler, J. F.; Babcock, R. W.

    1988-01-01

    Lunar laser-ranging data, accumulated between 1970 and 1986, are analyzed to estimate the deviation of the precession of the moon's orbit from the predictions of general relativity. No deviation from this predicted de Sitter precession rate of nearly 2 angular sec per century (sec/cy) is found, to within an estimated standard error of 0.04 sec/cy. This standard error, 2 percent of the predicted effect, incorporates an assessment of the likely contributions of systematic errors, and is about threefold larger than the statistical standard error.

  13. One loop graviton self-energy in a locally de Sitter background

    SciTech Connect

    tSAMIS, n.c. |; Woodard, R.P.

    1996-02-01

    The graviton tadpole has recently been computed at two loops in a locally de Sitter background. We apply intermediate results of this work to exhibit the graviton self-energy at one loop. This quantity is interesting both to check the accuracy of the first calculation and to understand the relaxation effect it reveals. In the former context we show that the self-energy obeys the appropriate Ward identity. We also show that its flat space limit agrees with the flat space result obtained by Capper in what should be the same gauge. 15 refs., 4 figs., 10 tabs.

  14. Mode analysis and Ward identities for perturbative quantum gravity in de Sitter space

    NASA Astrophysics Data System (ADS)

    Tsamis, N. C.; Woodard, R. P.

    1992-10-01

    We study linearized gravitons on the D-dimensional open submanifold spanned by de Sitter conformal coordinates. The physical modes are found in the same way as for flat space by imposing exact gauge conditions on the invariant field equations and then exploiting the residual gauge freedom of solutions. The resulting polatization tensors have vanishing zero components and are transverse and traceless, just as in flat space. We also show that vacua exist such that the ghost and graviton propagators obey the Ward identity relating them.

  15. Mode analysis and Ward identities for perturbative quantum gravity in de Sitter space

    NASA Astrophysics Data System (ADS)

    Tsamis, N. C.; Woodard, R. P.

    1992-06-01

    We study linearized gravitons on the D-dimensional open submanifold spanned by de Sitter conformal coordinates. The physical modes are found in the same way as for flat space by imposing exact gauge conditions on the invariant field equations and then exploiting the residual gauge freedom of solutions. The resulting polarization tensors have vanishing zero components and are transverse and traceless, just as in flat space. We also show that vacua exist such that the ghost and graviton propagators obey the Ward identity relating them.

  16. Rotating black hole in asymptotic de Sitter space: Perturbation of the space-time with spin fields

    SciTech Connect

    Khanal, U.

    1983-09-15

    The Newman-Penrose formalism is used to work with gravitational, electromagnetic, and Dirac field perturbations of the Kerr--de Sitter space. It is shown that the resulting equations are separable, and the radial parts (for the massless fields) combine into a master equation resembling that of Teukolsky. This master equation includes the Teukolsky equation and the equation arising from the de Sitter--Schwarzschild universe, and can be reduced to these cases under appropriate limiting conditions. Finally, the radial parts of the electromagnetic and neutrino fields are transformed to the form of the one-dimensional barrier-penetration equation.

  17. Hawking radiation of stationary and non-stationary Kerr-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Singh, T. Ibungochouba

    2015-07-01

    Hawking radiation of the stationary Kerr-de Sitter black hole is investigated using the relativistic Hamilton-Jacobi method. Meanwhile, extending this work to a non-stationary black hole using Dirac equations and generalized tortoise coordinate transformation, we derived the locations, the temperature of the thermal radiation as well as the maximum energy of the non-thermal radiation. It is found that the surface gravity and the Hawking temperature depend on both time and different angles. An extra coupling effect is obtained in the thermal radiation spectrum of Dirac particles which is absent from thermal radiation of scalar particles. Further, the chemical potential derived from the thermal radiation spectrum of scalar particle has been found to be equal to the highest energy of the negative energy state of the scalar particle in the non-thermal radiation for the Kerr-de Sitter black hole. It is also shown that for stationary black hole space time, these two different methods give the same Hawking radiation temperature.

  18. Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Bavarsad, Ehsan; Stahl, Clément; Xue, She-Sheng

    2016-11-01

    We consider a charged scalar field in a D -dimensional de Sitter spacetime and investigate pair creation by a Schwinger mechanism in a constant electric field background. Using a semiclassical approximation the current of the created pairs has been estimated. We find that the semiclassical current of the created pairs in the strong electric field limit responds as ED/2. Going further but restricting to D =3 dimensional de Sitter spacetime, the quantum expectation value of the spacelike component of the induced current has been computed in the in-vacuum state by applying an adiabatic subtraction scheme. We find that, in the strong electric field limit, the current responds as E3/2. In the weak electric field limit the current has a linear response in E and an inverse dependence on the mass of the scalar field. In the case of a massless scalar field, the current varies with E-1 which leads to a phenomenon of infrared hyperconductivity. A new relation between infrared hyperconductivity, tachyons, and conformality is discussed, and a scheme to avoid an infrared hyperconductivity regime is proposed. In D dimension, we eventually presented some first estimates of the backreaction of the Schwinger pairs to the gravitational field, and we find a decrease of the Hubble constant due to the pair creation.

  19. Infrared dynamics of the massive ϕ4 theory on de Sitter space

    NASA Astrophysics Data System (ADS)

    Akhmedov, E. T.; Popov, F. K.; Slepukhin, V. M.

    2013-07-01

    We study massive real scalar ϕ4 theory in the expanding Poincare patch of de Sitter space. We calculate the leading two-loop infrared contribution to the two-point function in this theory. We do that for the massive fields both from the principal and complementary series. As can be expected at this order, light fields from the complementary series show stronger infrared effects than the heavy fields from the principal one. For the principal series, unlike the complementary one, we can derive the kinetic equation from the system of Dyson-Schwinger equation, which allows us to sum up the leading infrared contributions from all loops. We find two peculiar solutions of the kinetic equation. One of them describes the stationary Gibbons-Hawking-type distribution for the density per comoving volume. Another solution shows explosive (square root of the pole in finite proper time) growth of the particle number density per comoving volume. That signals the possibility of the destruction of the expanding Poincaré patch even by the very massive fields. We conclude with the consideration of the infrared divergences in global de Sitter space and in its contracting Poincaré patch.

  20. Massive gravity in de Sitter space via the gravitational Higgs mechanism

    SciTech Connect

    Iglesias, Alberto; Kakushadze, Zurab

    2010-12-15

    In this paper we discuss massive gravity in de Sitter space via the gravitational Higgs mechanism, which provides a nonlinear definition thereof. The Higgs scalars are described by a nonlinear sigma model, which includes higher derivative terms required to obtain the Fierz-Pauli mass term. Using the aforesaid nonperturbative definition, we address the appearance of an enhanced local symmetry and a null norm state in the linearized massive gravity in de Sitter space at the special value of the graviton mass to the Hubble parameter ratio. By studying full nonperturbative equations of motion, we argue that there is no enhanced symmetry in the full nonlinear theory. We then argue that in the full nonlinear theory no null norm state is expected to arise at the aforesaid special value. This suggests that no ghost might be present for lower graviton mass values and the full nonlinear theory might be unitary for all values of the graviton mass and the Hubble parameter with no van Dam-Veltman-Zakharov discontinuity. We argue that this is indeed the case by studying the full nonlinear Hamiltonian for the relevant conformal and helicity-0 longitudinal modes. In particular, we argue that no negative norm state is present in the full nonlinear theory.

  1. Massive gravity on de Sitter and unique candidate for partially massless gravity

    SciTech Connect

    Rham, Claudia de; Renaux-Petel, Sébastien E-mail: srenaux@lpthe.jussieu.fr

    2013-01-01

    We derive the decoupling limit of Massive Gravity on de Sitter in an arbitrary number of space-time dimensions d. By embedding d-dimensional de Sitter into d+1-dimensional Minkowski, we extract the physical helicity-1 and helicity-0 polarizations of the graviton. The resulting decoupling theory is similar to that obtained around Minkowski. We take great care at exploring the partially massless limit and define the unique fully non-linear candidate theory that is free of the helicity-0 mode in the decoupling limit, and which therefore propagates only four degrees of freedom in four dimensions. In the latter situation, we show that a new Vainshtein mechanism is at work in the limit m{sup 2} → 2H{sup 2} which decouples the helicity-0 mode when the parameters are different from that of partially massless gravity. As a result, there is no discontinuity between massive gravity and its partially massless limit, just in the same way as there is no discontinuity in the massless limit of massive gravity. The usual bounds on the graviton mass could therefore equivalently well be interpreted as bounds on m{sup 2}−2H{sup 2}. When dealing with the exact partially massless parameters, on the other hand, the symmetry at m{sup 2} = 2H{sup 2} imposes a specific constraint on matter. As a result the helicity-0 mode decouples without even the need of any Vainshtein mechanism.

  2. Strong Enrichment of Aromatic Residues in Binding Sites from a Charge-neutralized Hyperthermostable Sso7d Scaffold Library*

    PubMed Central

    Kiefer, Jonathan D.; Srinivas, Raja R.; Lobner, Elisabeth; Tisdale, Alison W.; Mehta, Naveen K.; Yang, Nicole J.; Tidor, Bruce; Wittrup, K. Dane

    2016-01-01

    The Sso7d protein from the hyperthermophilic archaeon Sulfolobus solfataricus is an attractive binding scaffold because of its small size (7 kDa), high thermal stability (Tm of 98 °C), and absence of cysteines and glycosylation sites. However, as a DNA-binding protein, Sso7d is highly positively charged, introducing a strong specificity constraint for binding epitopes and leading to nonspecific interaction with mammalian cell membranes. In the present study, we report charge-neutralized variants of Sso7d that maintain high thermal stability. Yeast-displayed libraries that were based on this reduced charge Sso7d (rcSso7d) scaffold yielded binders with low nanomolar affinities against mouse serum albumin and several epitopes on human epidermal growth factor receptor. Importantly, starting from a charge-neutralized scaffold facilitated evolutionary adaptation of binders to differentially charged epitopes on mouse serum albumin and human epidermal growth factor receptor, respectively. Interestingly, the distribution of amino acids in the small and rigid binding surface of enriched rcSso7d-based binders is very different from that generally found in more flexible antibody complementarity-determining region loops but resembles the composition of antibody-binding energetic hot spots. Particularly striking was a strong enrichment of the aromatic residues Trp, Tyr, and Phe in rcSso7d-based binders. This suggests that the rigidity and small size of this scaffold determines the unusual amino acid composition of its binding sites, mimicking the energetic core of antibody paratopes. Despite the high frequency of aromatic residues, these rcSso7d-based binders are highly expressed, thermostable, and monomeric, suggesting that the hyperstability of the starting scaffold and the rigidness of the binding surface confer a high tolerance to mutation. PMID:27582495

  3. Genetic Variation of an Odorant Receptor OR7D4 and Sensory Perception of Cooked Meat Containing Androstenone

    PubMed Central

    Lunde, Kathrine; Egelandsdal, Bjørg; Skuterud, Ellen; Mainland, Joel D.; Lea, Tor; Hersleth, Margrethe; Matsunami, Hiroaki

    2012-01-01

    Although odour perception impacts food preferences, the effect of genotypic variation of odorant receptors (ORs) on the sensory perception of food is unclear. Human OR7D4 responds to androstenone, and genotypic variation in OR7D4 predicts variation in the perception of androstenone. Since androstenone is naturally present in meat derived from male pigs, we asked whether OR7D4 genotype correlates with either the ability to detect androstenone or the evaluation of cooked pork tainted with varying levels of androstenone within the naturally-occurring range. Consistent with previous findings, subjects with two copies of the functional OR7D4 RT variant were more sensitive to androstenone than subjects carrying a non-functional OR7D4 WM variant. When pork containing varying levels of androstenone was cooked and tested by sniffing and tasting, subjects with two copies of the RT variant tended to rate the androstenone-containing meat as less favourable than subjects carrying the WM variant. Our data is consistent with the idea that OR7D4 genotype predicts the sensory perception of meat containing androstenone and that genetic variation in an odorant receptor can alter food preferences. PMID:22567099

  4. De Sitter vacua from a D-term generated racetrack potential in hypersurface Calabi-Yau compactifications

    NASA Astrophysics Data System (ADS)

    Braun, Andreas P.; Rummel, Markus; Sumitomo, Yoske; Valandro, Roberto

    2015-12-01

    In [1] a mechanism to fix the closed string moduli in a de Sitter minimum was proposed: a D-term potential generates a linear relation between the volumes of two rigid divisors which in turn produces at lower energies a race-track potential with de Sitter minima at exponentially large volume. In this paper, we systematically search for implementations of this mechanism among all toric Calabi-Yau hypersurfaces with h 1,1 ≤ 4 from the Kreuzer-Skarke list. For these, topological data can be computed explicitly allowing us to find the subset of three-folds which have two rigid toric divisors that do not intersect each other and that are orthogonal to h 1,1 - 2 independent four-cycles. These manifolds allow to find D7-brane configurations compatible with the de Sitter uplift mechanism and we find an abundance of consistent choices of D7-brane fluxes inducing D-terms leading to a de Sitter minimum. Finally, we work out a couple of models in detail, checking the global consistency conditions and computing the value of the potential at the minimum.

  5. The structure of perturbative quantum gravity on a de Sitter background

    SciTech Connect

    Tsamis, N.C.; Woodward, R.P.

    1992-05-01

    Classical gravitation on de Sitter space suffers from a linearization instability. One consequence is that the response to a spatially localized distribution of positive energy cannot be globally regular. We use this fact to show that no causal Green`s function can give the correct linearized response to certain bilocalized distributions, even though these distributions obey the constraints of linearization stability. We avoid the problem by working on the open submanifold spanned by conformal coordinates. The retarded Green`s function is first computed in a simple gauge, then the rest of the propagator is inferred by analyticity -- up to the usual ambiguity about real, analytic and homogeneous terms. We show that the latter can be chosen so as to give a propagator which does not grow in any direction. The ghost propagator is also given and the interaction vertices are worked out.

  6. The structure of perturbative quantum gravity on a de Sitter background

    SciTech Connect

    Tsamis, N.C. . Dept. of Physics); Woodward, R.P. . Dept. of Physics)

    1992-05-01

    Classical gravitation on de Sitter space suffers from a linearization instability. One consequence is that the response to a spatially localized distribution of positive energy cannot be globally regular. We use this fact to show that no causal Green's function can give the correct linearized response to certain bilocalized distributions, even though these distributions obey the constraints of linearization stability. We avoid the problem by working on the open submanifold spanned by conformal coordinates. The retarded Green's function is first computed in a simple gauge, then the rest of the propagator is inferred by analyticity -- up to the usual ambiguity about real, analytic and homogeneous terms. We show that the latter can be chosen so as to give a propagator which does not grow in any direction. The ghost propagator is also given and the interaction vertices are worked out.

  7. Reply to "Comment on `Fermion production in a magnetic field in a de Sitter universe"'

    NASA Astrophysics Data System (ADS)

    Crucean, Cosmin; Bǎloi, Mihaela-Andreea

    2017-02-01

    In this paper, we study the problem of gauge invariance of the first order transition amplitudes in de Sitter QED in the Coulomb gauge. We consider the gauge transformations which preserve the Coulomb gauge, that contain the gradient of the gauge function. The final results prove that the first order transition amplitudes do not change at a gradient transformation of the vector potential because the only allowed transformation is Λ =0 . Our results suggest that the remarks made in the comment by Nicolaevici and Farkas [this issue, Phys. Rev. D 95, 048501 (2017), 10.1103/PhysRevD.95.048501] are not directly applicable to the results in our paper since their proposed gauge transformations do not preserve the Coulomb gauge.

  8. The Solution of Dirac Equation in Quasi-Extreme REISSNER-NORDSTRÖM de Sitter Space

    NASA Astrophysics Data System (ADS)

    Lyu, Yan; Cui, Song; Liu, Ling

    The radial parts of Dirac equation between the outer black hole horizon and the cosmological horizon in quasi-extreme Reissner-Nordström de Sitter (RNdS) geometry is solved numerically. We use an accurate polynomial approximation to mimic the modified tortoise coordinate hat r*(r), for obtaining the inverse function r=r(hat r*) and V=V(hat r*). We then use a quantum mechanical method to solve the wave equation and give the reflection and transmission coefficients. We concentrate on two limiting cases. The first case is when the two horizons are close to each other, and the second case is when the horizons are far apart.

  9. Real scalar field scattering with polynomial approximation around Schwarzschild—de Sitter black-hole

    NASA Astrophysics Data System (ADS)

    Liu, Mo-Lin; Liu, Hong-Ya; Zhang, Jing-Fei; Yu, Fei

    2008-05-01

    As one of the fitting methods, the polynomial approximation is effective to process sophisticated problem. In this paper, we employ this approach to handle the scattering of scalar field around the Schwarzschild—de Sitter black-hole. The complicated relationship between tortoise coordinate and radial coordinate is replaced by the approximate polynomial. The Schrödinger-like equation, the real boundary conditions and the polynomial approximation construct a full Sturm-Liouville type problem. Then this boundary value problem can be solved numerically for two limiting cases: the first one is the Nariai black-hole whose horizons are close to each other, the second one is the black-hole with the horizons widely separated. Compared with previous results (Brevik and Tian), the field near the event horizon and cosmological horizon can have a better description.

  10. Quantum radiation of Maxwell’s electromagnetic field in nonstationary Kerr-de Sitter black hole

    NASA Astrophysics Data System (ADS)

    Ibungochouba Singh, T.; Ablu Meitei, I.; Yugindro Singh, K.

    2016-03-01

    Quantum radiation properties of nonstationary Kerr-de Sitter (KdS) black hole is investigated using the method of generalized tortoise coordinate transformation. The locations of horizons and the temperature of the thermal radiation as well as the maximum energy of the nonthermal radiation are derived. It is found that the surface gravity and the Hawking temperature depend on both time and different angles. An extra coupling effect is obtained in the thermal radiation spectrum of Maxwell’s electromagnetic field equations which is absent in the thermal radiation spectrum of scalar particles. Further, the chemical potential derived from the thermal radiation spectrum of scalar particle has been found to be equal to the highest energy of the negative energy state of the scalar particle in the nonthermal radiation for KdS black hole. It is also shown that the generalized tortoise coordinate transformation produces a constant term in the expression of the surface gravity and Hawking temperature.

  11. Numerical solution of the Dirac equation in Schwarzschild de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Lyu, Y.; Gui, Y. X.

    2007-02-01

    The radial parts of the Dirac equation between the inner and the outer horizon in Schwarzschild-de Sitter geometry are solved. Two limiting cases are concerned. The first case is when the two horizons are far apart and the second case is when the horizons are close to each other. In each case, a 'tangent' approximation is used to replace the modified 'tortoise' coordinate r*, which leads to a simple analytically invertible relation between r* and the radius r. The potential V(r*) is replaced by a collection of step functions in sequence. Then the solutions of the wave equation as well as the reflection and transmission coefficients are computed by a quantum mechanical method.

  12. Infrared behavior and gauge artifacts in de Sitter spacetime: the photon field.

    PubMed

    Youssef, A

    2011-07-08

    We study the infrared (long-distance) behavior of the free photon field in de Sitter spacetime. Using a two-parameter family of gauge-fixing terms, we show that the infrared (IR) behavior of the two-point function is highly gauge-dependent and ranges from vanishing to growing. This situation is in disagreement with its counterpart in flat spacetime, where the two-point function vanishes in the IR region for any choice of the gauge-fixing parameters. A criterion to isolate the physical part of the two-point function is given and is shown to lead to a well-behaved two-point function in the IR region.

  13. 2D anti{endash}de Sitter gravity as a conformally invariant mechanical system

    SciTech Connect

    Cadoni, M.; Carta, P.; Klemm, D.; Mignemi, S.

    2001-06-15

    We show that two-dimensional (2D) AdS gravity induces on the spacetime boundary a conformally invariant dynamics that can be described in terms of a de Alfaro{endash}Fubini{endash}Furlan model coupled to an external source with conformal dimension 2. The external source encodes information about the gauge symmetries of the 2D gravity system. Alternatively, there exists a description in terms of a mechanical system with anholonomic constraints. The considered systems are invariant under the action of the conformal group generated by a Virasoro algebra, which occurs also as an asymptotic symmetry algebra of two-dimensional anti{endash}de Sitter space. We calculate the central charge of the algebra and find perfect agreement between the statistical and thermodynamical entropies of AdS{sub 2} black holes.

  14. The stability of de Sitter space with a scalar quantum field (II). The linear analysis

    NASA Astrophysics Data System (ADS)

    Rogers, Barrett; Isaacson, Jeffrey A.

    1992-01-01

    Using the semiclassical Einstein equations, we study the spatially homogeneous perturbations of a spatially flat de Sitter metric arising from fluctuations of a scalar quantum field about the Bunch-Davies vacuum state. The exact solution for the metric perturbation in the linear approzimation is obtained in terms of its Laplace transform, and analyzed for late times and arbitrary initial conditions. The results indicate the existence of only two undamped modes: (i) a "neutrally stable" mode, which derives from a spatial coordinate re-scaling symmetry in flat, Robertson-Walker space-times, and (ii) an unstable but unphysical "ghost" mode with a typical time scale m P-1 = G, which is related to the Landau ghost of the underlying quantum field theory. We show how to remove the latter mode by a restriction on the initial data. The existence of any physical instability in this spatially homogeneous system has been ruled out.

  15. Scalar field as a Bose-Einstein condensate in a Schwarzschild-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Castellanos, Elías; Escamilla-Rivera, Celia; Lämmerzahl, Claus; Macías, Alfredo

    In this paper, we analyze some properties of a scalar field configuration, where it is considered as a trapped Bose-Einstein condensate in a Schwarzschild-de Sitter background spacetime. In a natural way, the geometry of the curved spacetime provides an effective trapping potential for the scalar field configuration. This allows us to explore some thermodynamical properties of the system. Additionally, the curved geometry of the spacetime also induces a position-dependent self-interaction parameter, which can be interpreted as a kind of gravitational Feshbach resonance, that could affect the stability of the cloud and could be used to obtain information about the interactions among the components of the system.

  16. Gauge formulation of gravitation theories. I. The Poincaré, de Sitter, and conformal cases

    NASA Astrophysics Data System (ADS)

    Ivanov, E. A.; Niederle, J.

    1982-02-01

    The gauge formulations of various gravitation theories are discussed. They are based on the approach in which we have the group Diff R4 acting on xμ and in which we attach to every xμ a tangent space with the group of action H. Group H does not act on xμ and plays the role of an internal (global) symmetry group in the standard Yang-Mills theory. The matter fields in the theory transform according to representations of H and are assumed to be scalars of Diff R4. The full invariance group of the Lagrangian is then of the form Hloc⊗Diff R4. Here Hloc is a local gauge group obtained from H exactly as in the Yang-Mills theory. The approach has two characteristic features: (i) The group Hloc must be spontaneously broken in order to exclude redundant gauge fields (the Lorentz connections) from the theory in a way covariant with respect to the gauge transformations. (ii) To different H there correspond different gravitational theories, all invariant under Diff R4 but differing in backgrounds. Thus if H is isomorphic to the Poincaré group the corresponding gauge theory turns out to be equivalent to the usual Einstein or Einstein-Cartan theory of gravity in the Minkowski space as a background. The other choices for H considered in the paper are the de Sitter groups and the conformal group. They yield the Einstein theory with a negative (or positive) cosmological term in the corresponding de Sitter space and the Weyl or Cartan-Weyl theory (depending on realization of the conformal group), respectively.

  17. Ficus carica latex prevents invasion through induction of let-7d expression in GBM cell lines.

    PubMed

    Tezcan, Gulcin; Tunca, Berrin; Bekar, Ahmet; Yalcin, Murat; Sahin, Saliha; Budak, Ferah; Cecener, Gulsah; Egeli, Unal; Demir, Cevdet; Guvenc, Gokcen; Yilmaz, Gozde; Erkan, Leman Gizem; Malyer, Hulusi; Taskapilioglu, Mevlut Ozgur; Evrensel, Turkkan; Bilir, Ayhan

    2015-03-01

    Glioblastoma multiforme (GBM) is one of the deadliest human malignancies. A cure for GBM remains elusive, and the overall survival time is less than 1 year. Thus, the development of more efficient therapeutic approaches for the treatment of these patients is required. Induction of tumor cell death by certain phytochemicals derived from medicinal herbs and dietary plants has become a new frontier for cancer therapy research. Although the cancer suppressive effect of Ficus carica (fig) latex (FCL) has been determined in a few cancer types, the effect of this latex on GBM tumors has not been investigated. Therefore, in the current study, the anti-proliferative activity of FCL and the effect of the FCL-temozolomide (TMZ) combination were tested in the T98G, U-138 MG, and U-87 MG GBM cell lines using the WST-1 assay. The mechanism of cell death was analyzed using Annexin-V/FITC and TUNEL assays, and the effect of FCL on invasion was tested using the chick chorioallantoic membrane assay. To determine the effect of FCL on GBM progression, the expression levels of 40 GBM associated miRNAs were analyzed in T98G cells using RT-qPCR. According to the obtained data, FCL causes cell death in GBM cells with different responses to TMZ, and this effect is synergistically increased in combination with TMZ. In addition, the current study is the first to demonstrate the effect of FCL on modulation of let-7d expression, which may be an important underlying mechanism of the anti-invasive effect of this extract.

  18. 7D bosonic higher spin gauge theory: symmetry algebra and linearized constraints

    NASA Astrophysics Data System (ADS)

    Sezgin, E.; Sundell, P.

    2002-07-01

    We construct the minimal bosonic higher spin extension of the 7D AdS algebra SO(6,2), which we call hs(8 ∗) . The generators, which have spin s=1,3,5,… , are realized as monomials in Grassmann even spinor oscillators. Irreducibility, in the form of tracelessness, is achieved by modding out an infinite-dimensional ideal containing the traces. In this a key role is played by the tree bilinear traces which form an SU(2) K algebra. We show that gauging of hs(8 ∗) yields a spectrum of physical fields with spin s=0,2,4,… which make up a UIR of hs(8 ∗) isomorphic to the symmetric tensor product of two 6D scalar doubletons. The scalar doubleton is the unique SU(2) K invariant 6D doubleton. The spin s⩾2 sector comes from an hs(8 ∗) -valued one-form which also contains the auxiliary gauge fields required for writing the curvature constraints in covariant form. The physical spin s=0 field arises in a separate zero-form in a 'quasi-adjoint' representation of hs(8 ∗) . This zero-form also contains the spin s⩾2 Weyl tensors, i.e., the curvatures which are non-vanishing on-shell. We suggest that the hs(8 ∗) gauge theory describes the minimal bosonic, massless truncation of M-theory on AdS7× S4 in an unbroken phase where the holographic dual is given by N free (2,0) tensor multiplets for large N.

  19. Common base amplifier with 7 - dB gain at 176 GHz in InP mesa DHBT technology

    NASA Technical Reports Server (NTRS)

    Samoska, Lorene; Paidi, V.; Griffith, Z.; Dahlstrom, M.; Wei, Y.; Urteaga, M.; Rodell, M. J. W.; Fung, A.

    2004-01-01

    We report a single stage tunded amplifier that exhibits 7 dB small signal gain at 176 GHz. Common Base topology is chosen as it has the best maximum stable gain (MSG) in this frequency band when compared to common emitter and common collector topologies. The amplifiers are designed and fabricated in InP mesa double heterojunction bipolar transistor (DHBT) technology.

  20. Quantum corrections to the gravitational potentials of a point source due to conformal fields in de Sitter

    SciTech Connect

    Fröb, Markus B.; Verdaguer, Enric E-mail: enric.verdaguer@ub.edu

    2016-03-01

    We derive the leading quantum corrections to the gravitational potentials in a de Sitter background, due to the vacuum polarization from loops of conformal fields. Our results are valid for arbitrary conformal theories, even strongly interacting ones, and are expressed using the coefficients b and b' appearing in the trace anomaly. Apart from the de Sitter generalization of the known flat-space results, we find two additional contributions: one which depends on the finite coefficients of terms quadratic in the curvature appearing in the renormalized effective action, and one which grows logarithmically with physical distance. While the first contribution corresponds to a rescaling of the effective mass, the second contribution leads to a faster fall-off of the Newton potential at large distances, and is potentially measurable.

  1. Quantum radiation from an inertial scalar charge evolving in the de Sitter universe: Weak-field limit

    SciTech Connect

    Blaga, Robert

    2015-12-07

    We investigate the energy radiated by an inertial scalar charge evolving in the expanding Poincaré patch of de Sitter spacetime, in the framework of scalar QED perturbation theory. We approximate the transition amplitude in the small expansion parameter limit and show that the leading contribution to the radiated energy has the form of the energy radiated by an accelerated particle in Minkowski space.

  2. A line source in Minkowski for the de Sitter spacetime scalar Green's function: Massless minimally coupled case

    SciTech Connect

    Chu, Yi-Zen

    2014-09-15

    Motivated by the desire to understand the causal structure of physical signals produced in curved spacetimes – particularly around black holes – we show how, for certain classes of geometries, one might obtain its retarded or advanced minimally coupled massless scalar Green's function by using the corresponding Green's functions in the higher dimensional Minkowski spacetime where it is embedded. Analogous statements hold for certain classes of curved Riemannian spaces, with positive definite metrics, which may be embedded in higher dimensional Euclidean spaces. The general formula is applied to (d ≥ 2)-dimensional de Sitter spacetime, and the scalar Green's function is demonstrated to be sourced by a line emanating infinitesimally close to the origin of the ambient (d + 1)-dimensional Minkowski spacetime and piercing orthogonally through the de Sitter hyperboloids of all finite sizes. This method does not require solving the de Sitter wave equation directly. Only the zero mode solution to an ordinary differential equation, the “wave equation” perpendicular to the hyperboloid – followed by a one-dimensional integral – needs to be evaluated. A topological obstruction to the general construction is also discussed by utilizing it to derive a generalized Green's function of the Laplacian on the (d ≥ 2)-dimensional sphere.

  3. Regular black holes: Electrically charged solutions, Reissner-Nordstroem outside a de Sitter core

    SciTech Connect

    Lemos, Jose P. S.; Zanchin, Vilson T.

    2011-06-15

    To have the correct picture of a black hole as a whole, it is of crucial importance to understand its interior. The singularities that lurk inside the horizon of the usual Kerr-Newman family of black hole solutions signal an endpoint to the physical laws and, as such, should be substituted in one way or another. A proposal that has been around for sometime is to replace the singular region of the spacetime by a region containing some form of matter or false vacuum configuration that can also cohabit with the black hole interior. Black holes without singularities are called regular black holes. In the present work, regular black hole solutions are found within general relativity coupled to Maxwell's electromagnetism and charged matter. We show that there are objects which correspond to regular charged black holes, whose interior region is de Sitter, whose exterior region is Reissner-Nordstroem, and the boundary between both regions is made of an electrically charged spherically symmetric coat. There are several types of solutions: regular nonextremal black holes with a null matter boundary, regular nonextremal black holes with a timelike matter boundary, regular extremal black holes with a timelike matter boundary, and regular overcharged stars with a timelike matter boundary. The main physical and geometrical properties of such charged regular solutions are analyzed.

  4. No practical lensing by Lambda: Deflection of light in the Schwarzschild-de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Butcher, Luke M.

    2016-10-01

    Debate persists as to whether the cosmological constant Λ can directly modify the power of a gravitational lens. With the aim of reestablishing a consensus on this issue, I conduct a comprehensive analysis of gravitational lensing (to second order) in the Schwarzschild-de Sitter spacetime, wherein the effects of Λ should be most apparent. To second order, the effective lensing law is found to be in precise agreement with the Λ =0 result: αeff=4 m /beff+15 π m2/4 beff2+O (m3/beff3) , where the effective bending angle αeff and impact parameter beff are defined by the angles and angular diameter distances measured by a comoving cosmological observer. [These observers follow the timelike geodesic congruence which (i) respects the continuous symmetries of the spacetime and (ii) approaches local isotropy most rapidly far from the lens.] The effective lensing law can be derived using lensed or unlensed angular diameter distances, although the inherent ambiguity of unlensed distances generates an additional uncertainty O (m5/Λ beff7). These calculations do not rule out the possibility of an extremely small Λ -lensing effect O (m3/beff3); however, such an effect would be completely negligible in practice and will always be smaller than the uncertainty from unlensed distances. I conclude that, despite recent legitimate corrections to the formalism, the cosmological constant does not interfere with gravitational lensing in any practical way.

  5. Marginally outer trapped surfaces in de Sitter space by low-dimensional geometries

    NASA Astrophysics Data System (ADS)

    Musso, Emilio; Nicolodi, Lorenzo

    2015-10-01

    A marginally outer trapped surface (MOTS) in de Sitter spacetime is an oriented spacelike surface whose mean curvature vector is proportional to one of the two null sections of its normal bundle. Associated with a spacelike immersed surface there are two enveloping maps into Möbius space (the conformal 3-sphere), which correspond to the two future-directed null directions of the surface normal planes. We give a description of MOTSs based on the Möbius geometry of their envelopes. We distinguish three cases according to whether both, one, or none of the fundamental forms in the normal null directions vanish. Special attention is given to MOTSs with non-zero parallel mean curvature vector. It is shown that any such a surface is generically the central sphere congruence (conformal Gauss map) of a surface in Möbius space which is locally Möbius equivalent to a non-zero constant mean curvature surface in some space form subgeometry.

  6. Einstein-vector gravity, emerging gauge symmetry, and de Sitter bounce

    NASA Astrophysics Data System (ADS)

    Geng, Wei-Jian; Lü, H.

    2016-02-01

    We construct a class of Einstein-vector theories where the vector field couples bilinearly to the curvature polynomials of arbitrary order in such a way that only the Riemann tensor rather than its derivative enters the equations of motion. The theories can thus be ghost free. The U (1 ) gauge symmetry may emerge in the vacuum and also in some weak-field limit. We focus on the two-derivative theory and study a variety of applications. We find that in this theory, the energy-momentum tensor of dark matter provides a position-dependent gauge-violating term to the Maxwell field. We also use the vector as an inflaton and construct cosmological solutions. We find that the expansion can accelerate without a bare cosmological constant, indicating a new candidate for dark energy. Furthermore, we obtain exact solutions of de Sitter bounce, generated by the vector which behaves like a Maxwell field at later times. We also obtain a few new exact black holes that are asymptotic to flat and Lifshitz spacetimes. In addition, we construct exact wormholes and Randall-Sundrum II domain walls.

  7. Nonperturbative renormalization group for scalar fields in de Sitter space: Beyond the local potential approximation

    NASA Astrophysics Data System (ADS)

    Guilleux, Maxime; Serreau, Julien

    2017-02-01

    Nonperturbative renormalization group techniques have recently proven a powerful tool to tackle the nontrivial infrared dynamics of light scalar fields in de Sitter space. In the present article, we develop the formalism beyond the local potential approximation employed in earlier works. In particular, we consider the derivative expansion, a systematic expansion in powers of field derivatives, appropriate for long wavelength modes, that we generalize to the relevant case of a curved metric with Lorentzian signature. The method is illustrated with a detailed discussion of the so-called local potential approximation prime which, on top of the full effective potential, includes a running (but field-independent) field renormalization. We explicitly compute the associated anomalous dimension for O (N ) theories. We find that it can take large values along the flow, leading to sizable differences as compared to the local potential approximation. However, it does not prevent the phenomenon of gravitationally induced dimensional reduction pointed out in previous studies. We show that, as a consequence, the effective potential at the end of the flow is unchanged as compared to the local potential approximation, the main effect of the running anomalous dimension being merely to slow down the flow. We discuss some consequences of these findings.

  8. Tunneling probability for the birth of an asymptotically de Sitter universe

    SciTech Connect

    Acacio de Barros, J.; Correa Silva, E. V.; Monerat, G. A.; Oliveira-Neto, G.; Ferreira Filho, L. G.; Romildo, P. Jr.

    2007-05-15

    In the present work, we quantize a closed Friedmann-Robertson-Walker model in the presence of a positive cosmological constant and radiation. It gives rise to a Wheeler-DeWitt equation for the scale factor which has the form of a Schroedinger equation for a potential with a barrier. We solve it numerically and determine the tunneling probability for the birth of a asymptotically DeSitter, inflationary universe, initially, as a function of the mean energy of the initial wave function. Then, we verify that the tunneling probability increases with the cosmological constant, for a fixed value of the mean energy of the initial wave function. Our treatment of the problem is more general than previous ones, based on the WKB approximation. That is the case because we take into account the fact that the scale factor (a) cannot be smaller than zero. It means that, one has to introduce an infinity potential wall at a=0, which forces any wave packet to be zero there. That condition introduces new results, in comparison with previous works.

  9. Structural basis for the binding of the neutralizing antibody, 7D11, to the poxvirus L1 protein

    SciTech Connect

    Su, Hua-Poo; Golden, Joseph W.; Gittis, Apostolos G.; Hooper, Jay W.; Garboczi, David N.

    2007-11-25

    Medical countermeasures to prevent or treat smallpox are needed due to the potential use of poxviruses as biological weapons. Safety concerns with the currently available smallpox vaccine indicate a need for research on alternative poxvirus vaccine strategies. Molecular vaccines involving the use of proteins and/or genes and recombinant antibodies are among the strategies under current investigation. The poxvirus L1 protein, encoded by the L1R open reading frame, is the target of neutralizing antibodies and has been successfully used as a component of both protein subunit and DNA vaccines. L1-specific monoclonal antibodies (e.g., mouse monoclonal antibody mAb-7D11, mAb-10F5) with potent neutralizing activity bind L1 in a conformation-specific manner. This suggests that proper folding of the L1 protein used in molecular vaccines will affect the production of neutralizing antibodies and protection. Here, we co-crystallized the Fab fragment of mAb-7D11 with the L1 protein. The crystal structure of the complex between Fab-7D11 and L1 reveals the basis for the conformation-specific binding as recognition of a discontinuous epitope containing two loops that are held together by a disulfide bond. The structure of this important conformational epitope of L1 will contribute to the development of molecular poxvirus vaccines and also provides a novel target for anti-poxvirus drugs. In addition, the sequence and structure of Fab-7D11 will contribute to the development of L1-targeted immunotherapeutics.

  10. Induced fermionic currents in de Sitter spacetime in the presence of a compactified cosmic string

    NASA Astrophysics Data System (ADS)

    Mohammadi, A.; Bezerra de Mello, E. R.; Saharian, A. A.

    2015-07-01

    We investigate the vacuum fermionic currents in the geometry of a compactified cosmic string on the background of de Sitter (dS) spacetime. The currents are induced by magnetic fluxes running along the cosmic string and enclosed by the compact dimension. We show that the vacuum charge and the radial component of the current density vanish. By using the Abel-Plana summation formula, the azimuthal and axial currents are explicitly decomposed into two parts: the first one corresponds to the geometry of a straight cosmic string, and the second one is induced by the compactification of the string along its axis. For the axial current the first part vanishes and the corresponding topological part is an even periodic function of the magnetic flux along the string axis and an odd periodic function of the flux enclosed by the compact dimension with the periods equal to the flux quantum. The azimuthal current density is an odd periodic function of the flux along the string axis and an even periodic function of the flux enclosed by the compact dimension with the same period. Depending on the magnetic fluxes, the planar angle deficit can either enhance or reduce the azimuthal and axial currents. The influence of the background gravitational field on the vacuum currents is crucial at distances from the string larger than the dS curvature radius. In particular, for the geometry of a straight cosmic string and for a massive fermionic field, we show that the decay of the azimuthal current density is damping oscillatory with the amplitude inversely proportional to the fourth power of the distance from the string. This behavior is in clear contrast with the case of the string in Minkowski bulk, where the current density is exponentially suppressed at large distances.

  11. Aspects of hairy black holes

    SciTech Connect

    Anabalón, Andrés; Astefanesei, Dumitru

    2015-03-26

    We review the existence of exact hairy black holes in asymptotically flat, anti-de Sitter and de Sitter space-times. We briefly discuss the issue of stability and the charging of the black holes with a Maxwell field.

  12. An Exact Solution to the Quantized Electromagnetic Field in D-Dimensional de Sitter Space-Times

    NASA Astrophysics Data System (ADS)

    Alencar, G.; Guedes, I.; Landim, R. R.; Filho, R. N. Costa

    2012-12-01

    In this work, we investigate the quantum theory of light propagating in D-dimensional de Sitter space-times. To do so, we use the method of dynamic invariants to obtain the solution of the time-dependent Schrödinger equation. The quantum behavior of the electromagnetic field in this background is analyzed. As the electromagnetism loses its conformality in D≠4, we point out that there will be particle production and comoving objects will feel a Bunch-Davies thermal bath. This may become important in extra dimension physics and raises the intriguing possibility that precise measurements of the Cosmic Microwave Background could verify the existence of extra dimensions.

  13. Real Scalar Field Scattering Around the Extreme Reissner-Nordström Black Hole in de Sitter Spacetime

    NASA Astrophysics Data System (ADS)

    Guo, Guanghai; Yan, Pengfei; Wang, Suojie

    2015-02-01

    The real scalar field scattering of the extreme Reissner-Nordström black hole in de Sitter spacetime is investigated numerically via the polynomial approximation. It is found that the scalar field behaves like harmonic waves under the tortoise coordinate, while piles up near the outer event horizon and the cosmological horizon. The abnormity in previous work is eliminated by appropriate application of the boundary conditions in numerical calculations. Substituting the continuous effective potential with a stair potential of n steps, we evaluate the transmission and reflection coefficients of the scalar field in high and low energy regimes, where an asymptotical formula is derived.

  14. Quantum-gravitational effects on gauge-invariant scalar and tensor perturbations during inflation: The de Sitter case

    NASA Astrophysics Data System (ADS)

    Brizuela, David; Kiefer, Claus; Krämer, Manuel

    2016-05-01

    We present detailed calculations for quantum-gravitational corrections to the power spectra of gauge-invariant scalar and tensor perturbations during inflation. This is done by performing a semiclassical Born-Oppenheimer type of approximation to the Wheeler-DeWitt equation, from which we obtain a Schrödinger equation with quantum-gravitational correction terms. As a first step, we perform our calculation for a de Sitter universe and find that the correction terms lead to an enhancement of power on the largest scales.

  15. Inverse scattering at fixed energy for massive charged Dirac fields in de Sitter-Reissner-Nordström black holes

    NASA Astrophysics Data System (ADS)

    Gobin, Damien

    2015-05-01

    In this paper, we consider massive charged Dirac fields propagating in the exterior region of de Sitter-Reissner-Nordström black holes. We show that the parameters of such black holes are uniquely determined by the partial knowledge of the corresponding scattering operator S(λ ) at a fixed energy λ. More precisely, we consider the partial wave scattering operators S(λ ,n) (here λ \\in {R} is the energy and n\\in {{{N}}\\star } denotes the angular momentum) defined as the restrictions of the full scattering operator on a well-chosen basis of spin-weighted spherical harmonics. We prove that the knowledge of the scattering operators S(λ ,n), for all n\\in L, where L is a subset of {{{N}}\\star } that satisfies the Müntz condition {{\\sum }n\\in L}\\frac{1}{n} = +∞ , makes it possible to recover the mass, the charge, and the cosmological constant of a de Sitter-Reissner-Nordström black hole. The main tool consists in the complexification of the angular momentum n and in studying the analytic properties of the ‘unphysical’ corresponding data in the complex variable z.

  16. Coulomb's law corrections and fermion field localization in a tachyonic de Sitter thick braneworld

    NASA Astrophysics Data System (ADS)

    Cartas-Fuentevilla, Roberto; Escalante, Alberto; Germán, Gabriel; Herrera-Aguilar, Alfredo; Rigel Mora-Luna, Refugio

    2016-05-01

    Following recent studies which show that it is possible to localize gravity as well as scalar and gauge vector fields in a tachyonic de Sitter thick braneworld, we investigate the solution of the gauge hierarchy problem, the localization of fermion fields in this model, the recovering of the Coulomb law on the non-relativistic limit of the Yukawa interaction between bulk fermions and gauge bosons localized in the brane, and confront the predicted 5D corrections to the photon mass with its upper experimental/observational bounds, finding the model physically viable since it passes these tests. In order to achieve the latter aims we first consider the Yukawa interaction term between the fermionic and the tachyonic scalar fields MF(T)ΨΨ̅ in the action and analyze four distinct tachyonic functions F(T) that lead to four different structures of the respective fermionic mass spectra with different physics. In particular, localization of the massless left-chiral fermion zero mode is possible for three of these cases. We further analyze the phenomenology of these Yukawa interactions among fermion fields and gauge bosons localized on the brane and obtain the crucial and necessary information to compute the corrections to Coulomb's law coming from massive KK vector modes in the non-relativistic limit. These corrections are exponentially suppressed due to the presence of the mass gap in the mass spectrum of the bulk gauge vector field. From our results we conclude that corrections to Coulomb's law in the thin brane limit have the same form (up to a numerical factor) as far as the left-chiral massless fermion field is localized on the brane. Finally we compute the corrections to the Coulomb's law for an arbitrarily thick brane scenario which can be interpreted as 5D corrections to the photon mass. By performing consistent estimations with brane phenomenology, we found that the predicted corrections to the photon mass, which are well bounded by the experimentally observed or

  17. Coulomb’s law corrections and fermion field localization in a tachyonic de Sitter thick braneworld

    SciTech Connect

    Cartas-Fuentevilla, Roberto; Escalante, Alberto; Germán, Gabriel; Herrera-Aguilar, Alfredo; Mora-Luna, Refugio Rigel

    2016-05-11

    Following recent studies which show that it is possible to localize gravity as well as scalar and gauge vector fields in a tachyonic de Sitter thick braneworld, we investigate the solution of the gauge hierarchy problem, the localization of fermion fields in this model, the recovering of the Coulomb law on the non-relativistic limit of the Yukawa interaction between bulk fermions and gauge bosons localized in the brane, and confront the predicted 5D corrections to the photon mass with its upper experimental/observational bounds, finding the model physically viable since it passes these tests. In order to achieve the latter aims we first consider the Yukawa interaction term between the fermionic and the tachyonic scalar fields MF(T)ΨΨ-bar in the action and analyze four distinct tachyonic functions F(T) that lead to four different structures of the respective fermionic mass spectra with different physics. In particular, localization of the massless left-chiral fermion zero mode is possible for three of these cases. We further analyze the phenomenology of these Yukawa interactions among fermion fields and gauge bosons localized on the brane and obtain the crucial and necessary information to compute the corrections to Coulomb’s law coming from massive KK vector modes in the non-relativistic limit. These corrections are exponentially suppressed due to the presence of the mass gap in the mass spectrum of the bulk gauge vector field. From our results we conclude that corrections to Coulomb’s law in the thin brane limit have the same form (up to a numerical factor) as far as the left-chiral massless fermion field is localized on the brane. Finally we compute the corrections to the Coulomb’s law for an arbitrarily thick brane scenario which can be interpreted as 5D corrections to the photon mass. By performing consistent estimations with brane phenomenology, we found that the predicted corrections to the photon mass, which are well bounded by the experimentally

  18. The function of 7D-cadherins: a mathematical model predicts physiological importance for water transport through simple epithelia

    PubMed Central

    2011-01-01

    Background 7D-cadherins like LI-cadherin are cell adhesion molecules and represent exceptional members of the cadherin superfamily. Although LI-cadherin was shown to act as a functional Ca2+-dependent adhesion molecule, linking neighboring cells together, and to be dysregulated in a variety of diseases, the physiological role is still enigmatic. Interestingly 7D-cadherins occur only in the lateral plasma membranes of cells from epithelia of water transporting tissues like the gut, the liver or the kidney. Furthermore LI-cadherin was shown to exhibit a highly cooperative Ca2+-dependency of the binding activity. Thus it is tempting to assume that LI-cadherin regulates the water transport through the epithelium in a passive fashion by changing its binding activity in dependence on the extracellular Ca2+. Results We developed a simple mathematical model describing the epithelial lining of a lumen with a content of variable osmolarity covering an interstitium of constant osmolarity. The width of the lateral intercellular cleft was found to influence the water transport significantly. In the case of hypertonic luminal content a narrow cleft is necessary to further increase concentration of the luminal content. If the cleft is too wide, the water flux will change direction and water is transported into the lumen. Electron microscopic images show that in fact areas of the gut can be found where the lateral intercellular cleft is narrow throughout the lateral cell border whereas in other areas the lateral intercellular cleft is widened. Conclusions Our simple model clearly predicts that changes of the width of the lateral intercellular cleft can regulate the direction and efficiency of water transport through a simple epithelium. In a narrow cleft the cells can increase the concentration of osmotic active substances easily by active transport whereas if the cleft is wide, friction is reduced but the cells can hardly build up high osmotic gradients. It is now tempting to

  19. De novo sequencing, assembly and analysis of the genome of the laboratory strain Saccharomyces cerevisiae CEN.PK113-7D, a model for modern industrial biotechnology.

    PubMed

    Nijkamp, Jurgen F; van den Broek, Marcel; Datema, Erwin; de Kok, Stefan; Bosman, Lizanne; Luttik, Marijke A; Daran-Lapujade, Pascale; Vongsangnak, Wanwipa; Nielsen, Jens; Heijne, Wilbert H M; Klaassen, Paul; Paddon, Chris J; Platt, Darren; Kötter, Peter; van Ham, Roeland C; Reinders, Marcel J T; Pronk, Jack T; de Ridder, Dick; Daran, Jean-Marc

    2012-03-26

    Saccharomyces cerevisiae CEN.PK 113-7D is widely used for metabolic engineering and systems biology research in industry and academia. We sequenced, assembled, annotated and analyzed its genome. Single-nucleotide variations (SNV), insertions/deletions (indels) and differences in genome organization compared to the reference strain S. cerevisiae S288C were analyzed. In addition to a few large deletions and duplications, nearly 3000 indels were identified in the CEN.PK113-7D genome relative to S288C. These differences were overrepresented in genes whose functions are related to transcriptional regulation and chromatin remodelling. Some of these variations were caused by unstable tandem repeats, suggesting an innate evolvability of the corresponding genes. Besides a previously characterized mutation in adenylate cyclase, the CEN.PK113-7D genome sequence revealed a significant enrichment of non-synonymous mutations in genes encoding for components of the cAMP signalling pathway. Some phenotypic characteristics of the CEN.PK113-7D strains were explained by the presence of additional specific metabolic genes relative to S288C. In particular, the presence of the BIO1 and BIO6 genes correlated with a biotin prototrophy of CEN.PK113-7D. Furthermore, the copy number, chromosomal location and sequences of the MAL loci were resolved. The assembled sequence reveals that CEN.PK113-7D has a mosaic genome that combines characteristics of laboratory strains and wild-industrial strains.

  20. De novo sequencing, assembly and analysis of the genome of the laboratory strain Saccharomyces cerevisiae CEN.PK113-7D, a model for modern industrial biotechnology

    PubMed Central

    2012-01-01

    Saccharomyces cerevisiae CEN.PK 113-7D is widely used for metabolic engineering and systems biology research in industry and academia. We sequenced, assembled, annotated and analyzed its genome. Single-nucleotide variations (SNV), insertions/deletions (indels) and differences in genome organization compared to the reference strain S. cerevisiae S288C were analyzed. In addition to a few large deletions and duplications, nearly 3000 indels were identified in the CEN.PK113-7D genome relative to S288C. These differences were overrepresented in genes whose functions are related to transcriptional regulation and chromatin remodelling. Some of these variations were caused by unstable tandem repeats, suggesting an innate evolvability of the corresponding genes. Besides a previously characterized mutation in adenylate cyclase, the CEN.PK113-7D genome sequence revealed a significant enrichment of non-synonymous mutations in genes encoding for components of the cAMP signalling pathway. Some phenotypic characteristics of the CEN.PK113-7D strains were explained by the presence of additional specific metabolic genes relative to S288C. In particular, the presence of the BIO1 and BIO6 genes correlated with a biotin prototrophy of CEN.PK113-7D. Furthermore, the copy number, chromosomal location and sequences of the MAL loci were resolved. The assembled sequence reveals that CEN.PK113-7D has a mosaic genome that combines characteristics of laboratory strains and wild-industrial strains. PMID:22448915

  1. The general Taub-NUT-De Sitter metric as a self-dual Yang-Mills solution of gravity

    NASA Astrophysics Data System (ADS)

    Boutaleb-Joutei, H.

    1980-02-01

    We show in a simple and systematical way the self-duality constraints of certain SU(2) gauge fields can be used to rediscover the Einstein metrics. Starting with a metric tensor with two unknown functions, the self-duality constraints of the SU(2) gauge field obtained from the spin connections are studied. The general Taub-NUT-De Sitter metric is found to emerge quite simply as a solution, though the riemannian tensor of the metric itself is not self-dual in the general case. Different interesting limiting cases, such as the Eguchi-Hanson metric, are also obtained directly from the constraint equations. On leave of absence from Laboratoire de Physique Théorique de la Faculté des Sciences de Rabat, Morocco.

  2. Einstein's cosmology review of 1933: a new perspective on the Einstein-de Sitter model of the cosmos

    NASA Astrophysics Data System (ADS)

    O'Raifeartaigh, Cormac; O'Keeffe, Michael; Nahm, Werner; Mitton, Simon

    2015-09-01

    We present a first English translation and analysis of a little-known review of relativistic cosmology written by Albert Einstein in late 1932. The article, which was published in 1933 in a book of Einstein papers translated into French, contains a substantial review of static and dynamic relativistic models of the cosmos, culminating in a discussion of the Einstein-de Sitter model. The article offers a valuable contemporaneous insight into Einstein's cosmology in the early 1930s and confirms that his interest lay in the development of the simplest model of the cosmos that could account for observation. The article also confirms that Einstein did not believe that simplified relativistic models could give an accurate description of the early universe.

  3. Characterization of a new selective antagonist for angiotensin-(1-7), D-pro7-angiotensin-(1-7).

    PubMed

    Santos, Robson A S; Haibara, Andréa S; Campagnole-Santos, Maria José; Simões e Silva, Ana C; Paula, Renata D; Pinheiro, Sérgio V B; Leite, Maria Fátima; Lemos, Virginia S; Silva, Denise M R; Guerra, Mateus T; Khosla, Mahesh C

    2003-03-01

    Angiotensin-(1-7) [Ang-(1-7)] has biological actions that can often be distinguished from those of angiotensin II (Ang II). Recent studies indicate that the effects of Ang-(1-7) are mediated by specific receptor(s). We now report the partial characterization of a new antagonist selective for Ang-(1-7), D-Pro7-Ang-(1-7). D-Pro7-Ang-(1-7) (50 pmol) inhibited the hypertensive effect induced by microinjection of Ang-(1-7) [4+/-1 vs 21+/-2 mm Hg, 25 pmol Ang-(1-7) alone] into the rostral ventrolateral medulla without changing the effect of Ang II (16+/-2.5 vs 19+/-2.5 mm Hg after 25 pmol Ang II alone). At 10(-7) mol/L concentration, it completely blocked the endothelium-dependent vasorelaxation produced by Ang-(1-7) (10(-10) to 10(-6) mol/L) in the mouse aorta. The antidiuresis produced by Ang-(1-7) (40 pmol/100 g body weight) in water-loaded rats was also blocked by its analog [1 microg/100 g body weight; 3.08+/-0.8 vs 1.27+/-0.33 mL in Ang-(1-7)-treated rats]. D-Pro7-Ang-(1-7) at a molar ratio of 40:1 did not change the hypotensive effect of bradykinin. Moreover, D-Pro7-Ang-(1-7) did not affect the dipsogenic effect produced by intracerebroventricular administration of Ang II (11.4+/-1.15 vs 8.8+/-1.2 mL/h after Ang II) and did not show any demonstrable angiotensin-converting enzyme inhibitory activity in assays with the synthetic substrate Hip-His-Leu and rat plasma as a source of enzyme. Autoradiography studies with 125I-Ang-(1-7) in mouse kidney slices showed that D-Pro7-Ang-(1-7) competed for the binding of Ang-(1-7) to the cortical supramedullary region. In Chinese hamster ovary cells stably transfected with the AT1 receptor subtype, D-Pro7-Ang-(1-7) did not compete for the specific binding of 125I-Ang-II in concentrations up to 10(-6) mol/L. There was also no significant displacement of Ang II binding to angiotensin type 2 receptors in membrane preparations of adrenal medulla. These data indicate that D-Pro7-Ang-(1-7) is a selective antagonist for Ang-(1

  4. Potentiation of human papilloma vaccine candidate using naloxone/alum mixture as an adjuvant: increasing immunogenicity of HPV-16E7d vaccine

    PubMed Central

    Yasaghi, Mahsa; Mahdavi, Mehdi

    2016-01-01

    Objective(s): Many types of human papillomaviruses (HPVs) have been identified, with some leading to cancer and others to skin lesions such as anogenital warts. Studies have demonstrated an association between oncogenic HPV and cervical cancer and many researchers have focused on therapeutic vaccines development. At present, the modulatory effect of opioids on the innate and acquired immune system is characterized. Antagonists of opioid receptors such as naloxone (NLX) can contribute to the shifting Th2 response toward Th1. Herein; we studied the adjuvant activity of NLX/Alum mixture for improvement of the immunogenicity of HPV-16E7d vaccine. Materials and Methods: The mice were administered different regimens of vaccine; E7d, E7d-NLX, E7d-Alum, E7d-NLX-Alum, NLX, alum and PBS via subcutaneous route for three times with two weeks interval. Two weeks after the last immunization, the sera were assessed for total antibody, IgG1 and IgG2a with an optimized ELISA method. The splenocytes culture supernatant was analyzed by ELISA for the presence of IL-4, IFN-γ and IL-17 cytokines and lymphocyte proliferation was evaluated with Brdu method. Results: Immunization of mice with HPV-16 E7d vaccine formulated in NLX/Alum mixture significantly increased lymphocyte proliferation and Th1 and Th17 cytokines responses compared to other experimental groups. Analysis of humoral immune responses revealed that administration of vaccine with NLX/Alum mixture significantly increased specific IgG responses and also isotypes compared to control groups. Conclusion: NLX/Alum mixture as an adjuvant could improve cellular and humoral immune responses and the adjuvant maybe useful for HPV vaccines model for further studies in human clinical trial. PMID:27803788

  5. A novel function of microRNA let-7d in regulation of galectin-3 expression in attention deficit hyperactivity disorder rat brain.

    PubMed

    Wu, Lihui; Zhao, Qianlei; Zhu, Xuchao; Peng, Min; Jia, Chenyou; Wu, Wei; Zheng, Jing; Wu, Xing Zhong

    2010-11-01

    In this study we investigated the locomotor activity and non-selective attention in spontaneously hypertensive rats (SHR) with control Wistar-Kyoto (WKY) rats, which were employed as an attention deficit hyperactivity disorder (ADHD) model. In open-field test and làt maze, SHR rats were found to be much more spontaneously active than WKY rats. As compared with WKY rats, a lower level of galectin-3 was observed in SHR brain prefrontal cortex (PFC), which was the major affected brain area of ADHD. Through miRNA microarray screening, rno-let-7d was noted to be solely upregulated in SHR PFC. Interestingly, rno-let-7d had a binding site at galectin-3 mRNA and was shown to regulate galectin-3 3' untranslated region (UTR) directly. Mutation of galectin-3 3'UTR by one nucleotide of the seed sequence prevented rno-let-7d regulation of the 3' UTR completely. Although rno-let-7d did not directly regulate tyrosine hydroxylase (TH) 3'UTR, the level of galectin-3 was important for cAMP response element binding protein, the major transcript factor for TH gene. Either overexpression or downexpression of galectin-3 could result in modulation of TH expression in both PC12H and PC12L cells. In conclusion, our data suggested a novel function of rno-let-7d in regulation of galectin-3 and in ADHD development. Rno-let-7d, which is increased in the PFC of SHR brain, negatively regulated galectin-3, which is coupled with TH expression regulation.

  6. Efficacy of 14-d vs 7-d moxifloxacin-based triple regimens for second-line Helicobacter pylori eradication

    PubMed Central

    Hwang, Jae Jin; Lee, Dong Ho; Lee, Ae-Ra; Yoon, Hyuk; Shin, Cheol Min; Park, Young Soo; Kim, Nayoung

    2015-01-01

    AIM: To evaluate the efficacy of the 14-d moxifloxacin-based triple therapy for the second-line eradication of Helicobacter pylori (H. pylori) infection. METHODS: Between 2011 and 2013, we conducted a retrospective review of the medical records of 160 patients who had experienced failure of their first-line proton pump inhibitor-based eradication therapy and subsequently received the moxifloxacin-based triple therapy as a second-line eradication treatment regimen. The patients who were treated with the moxifloxacin-based triple therapy (oral 20 mg rabeprazole b.i.d., 1000 mg amoxicillin b.i.d., and 400 mg moxifloxacin q.d.) for 7 d were assigned to the RAM-7 group (n = 79) while those who took them for 14 days were assigned to RAM-14 group (n = 81). The eradication rates for both groups were determined by intention-to-treat (ITT) and per-protocol (PP) analyses. ITT analysis compared the treatment groups as originally allocated while the PP analysis including only those patients who had completed the treatment as originally allocated. Successful eradication therapy for H. pylori infection was defined as the documentation of a negative 13C-urea breath test 4 wk after the end of the eradication treatment. RESULTS: The overall ITT eradication rate was 76.2% (122/160). The final ITT eradication rates were 70.8% (56/79; 95%CI: 63.3%-77.1%) in the RAM-7 group and 81.4% (66/81; 95%CI: 74.6%-88.3%) in the RAM-14 group (P = 0.034). The overall PP eradication rate was 84.1% (122/145), and the final PP eradication rates were 77.7% (56/72; 95%CI: 70.2%-85.3%) in the RAM-7 group and 90.4% (66/73; 95%CI: 82.8%-98.1%) in the RAM-14 group (P = 0.017). The H. pylori-eradication rates in the RAM-14 group were significantly higher compared with that of the RAM-7 group according to both the ITT (P = 0.034) and the PP analyses (P = 0.017). Both groups exhibited good treatment compliance (RAM-7/RAM-14 group: 100%/100%). The adverse event rates were 19.4% (14/72) and 20.5% (15/73) in the

  7. MYC protein inhibits transcription of the microRNA cluster MC-let-7a-1~let-7d via noncanonical E-box.

    PubMed

    Wang, Zifeng; Lin, Sheng; Li, Julia Jun; Xu, Zhenhua; Yao, Hong; Zhu, Xiao; Xie, Dan; Shen, Zan; Sze, Johnny; Li, Kui; Lu, Gang; Chan, Danny Tat-Ming; Poon, Wai Sang; Kung, Hsiang-fu; Lin, Marie Chia-mi

    2011-11-18

    The human microRNA cluster MC-let-7a-1∼let-7d, with three members let-7a-1, let-7f-1, and let-7d, is an important cluster of the let-7 family. These microRNAs play critical roles in regulating development and carcinogenesis. Therefore, precise control of MC-let-7a-1∼let-7d level is critical for cellular functions. In this study, we first showed that the expression of these three members was significantly reduced in human hepatocellular carcinoma HepG2 cells as compared with the immortalized human liver L02 cells. We demonstrated that the MC-let-7a-1∼let-7d cluster was encoded by a single polycistronic transcript driven by a 10-kb upstream promoter, with two MYC-binding sites. Importantly, MYC inhibited MC-let-7a-1∼let-7d promoter activity via binding to the noncanonical E-box 3 downstream of the transcription start sites, whereas it enhanced promoter activity by binding to the canonical E-box 2 upstream of the transcription start sites. We found that although the binding affinity of MYC to E-box 2 was stronger than E-box 3, the binding quantum of MYC to E-box 3 was significantly higher in cancerous HepG2 cells as compared with the noncancerous L02 cells. In addition, forced expression of let-7 could reverse the MYC-mediated cell proliferation. These findings suggested that in L02 cells with a low level of MYC, MYC binds mainly to E-box 2 to enhance MC-let-7a-1∼let-7d expression. However, in HepG2 cells with an elevated MYC, the extra MYC could bind to E-box 3 to suppress the transcription of MC-let-7a-1∼let-7d and thus enable HepG2 cells to maintain a high level of MYC and a low level of let-7 microRNAs simultaneously.

  8. Fatal Community-acquired Pneumonia in Children Caused by Re-emergent Human Adenovirus 7d Associated with Higher Severity of Illness and Fatality Rate

    PubMed Central

    Yu, Zhiwu; Zeng, Zhiwei; Zhang, Jing; Pan, Yuxian; Chen, Manjun; Guo, Yonghui; Yu, Nan; Chodosh, James; Fu, Ning; Che, Xiaoyan; Zhang, Qiwei

    2016-01-01

    Human adenoviruses (HAdVs) are highly contagious pathogens causing acute respiratory disease (ARD), such as community-acquired pneumonia. HAdV-7d, a re-emergent genomic variant, has been recently reported in Asia and the United States after a several-decade absence. However, whether HAdV-7d is associated with higher severity than other types is currently unclear. In this study, the clinical and epidemiological investigation showed that fever, cough, and sore throat were the three most common respiratory symptoms of HAdV infections. HAdV-7 caused longer duration of fever, higher morbidity of tachypnea/dyspnea, pleural effusion, diarrhea, hepatosplenomegaly, consciousness alteration, as well as higher rates of pneumonia, mechanical ventilation and higher fatality rate (28.6%) than other types, particularly HAdV-3 and HAdV-2. The genomes of seven HAdV-7d isolates from mild, severe, and fatal cases were sequenced and highly similar with each other. Surprisingly, two isolates (2011, 2012) had 100% identical genomes with an earlier strain from a fatal ARD outbreak in China (2009), which elucidates the virus origin and confirms the unexpected HAdV genomic conservation and stability. Phylogenetic analysis indicated that L1 52/55-kDa DNA packaging protein may be associated with the higher severity of illness and fatality rate of HAdV-7. Clinicians need to be aware of HAdVs in children with ARD. PMID:27848998

  9. Role of hydrophobic core on the thermal stability of proteins - molecular dynamics simulations on a single point mutant of Sso7d abstract.

    PubMed

    Priyakumar, U Deva

    2012-01-01

    The role of salt bridges in chromatin protein Sso7d, from S. solfataricus has previously been shown to be crucial for its unusual high thermal stability. Experimental studies have shown that single site mutation of Sso7d (F31A) leads to a substantial decrease in the thermal stability of this protein due to distortion of the hydrophobic core. In the present study, we have performed a total of 0.2 s long molecular dynamics (MD) simulations on F31A at room temperature, and at 360 K, close to the melting temperature of the wild type (WT) protein to investigate the role of hydrophobic core on protein stability. Sso7d-WT was shown to be stable at both 300 and 360 K; however, F31A undergoes denaturation at 360 K, consistent with experimental results. The structural and energetic properties obtained using the analysis of MD trajectories indicate that the single mutation results in high flexibility of the protein, and loosening of intramolecular interactions. Correlation between the dynamics of the salt bridges with the structural transitions and the unfolding pathway indicate the importance of both salt bridges and hydrophobic in effecting thermal stability of proteins in general.

  10. A New General Tortoise Coordinate Transformation and Quantum Tunneling Effect of the Non-Stationary Higher Dimensional Vaidya-de Sitter Black Hole

    NASA Astrophysics Data System (ADS)

    Feng, Zhong-wen; Li, Guo-ping; Zhang, Yan; Zu, Xiao-tao

    2015-02-01

    In this paper, we combine the Hamilton-Jacobi equation with a new general tortoise coordinate transformation to study quantum tunneling of scalar particles and fermions from the non-stationary higher dimensional Vaidya-de Sitter black hole. The results show that Hamilton-Jacobi equation is a semi-classical foundation equation which can easily derived from the particles' dynamic equations, it can helps us understand the origin of Hawking radiation. Besides, based on the dimensional analysis, we believed that the new general tortoise coordinate transformation is more reasonable than old ones.

  11. Nonsingular AdS-dS transitions in a landscape scenario

    NASA Astrophysics Data System (ADS)

    Gupt, Brajesh; Singh, Parampreet

    2014-03-01

    Understanding transitions between different vacua of a multiverse allowing eternal inflation is an open problem whose resolution is important to gain insights on the global structure of the spacetime as well as the problem of measure. In the classical theory, transitions from the anti-de Sitter to de Sitter vacua are forbidden due to the big-crunch singularity. In this paper, we consider toy landscape potentials: a double well and a triple well potential allowing anti-de Sitter and de Sitter vacua, in the effective dynamics of loop quantum cosmology for the k=-1 FRW model. We show that due to the nonperturbative quantum gravity effects as understood in loop quantum cosmology, nonsingular anti-de Sitter to de Sitter transitions are possible. In the future evolution, an anti-de Sitter bubble universe does not encounter a big-crunch singularity but undergoes a big bounce occurring at a scale determined by the underlying quantum geometry. These nonsingular transitions provide a mechanism through which a probe or a "watcher," used to define a local measure, can safely evolve through the bounce and geodesics can be smoothly extended from anti-de Sitter to de Sitter vacua.

  12. Non-singular AdS-dS transitions in a landscape scenario

    NASA Astrophysics Data System (ADS)

    Gupt, Brajesh; Singh, Parampreet

    2014-03-01

    In the multiverse scanario allowing eternal inflation, it is an important problem to understand transitions between different vacua, of which the ones from anti-deSitter to de-Sitter is forbidden in the classical theory. In this talk, we consider toy landscape potentials: a double well and a triple well potential allowing anti-deSitter and de-Sitter vacua, in the effective dynamics of loop quantum cosmology for the k = - 1 FRW model. We show that due to the non-perturbative quantum gravity effects as understood in loop quantum cosmology, non-singular anti-deSitter to de-Sitter transitions are possible. In the future evolution, an anti-deSitter bubble universe does not encounter a big crunch singularity but undergoes a big bounce occurring at a scale determined by the underlying quantum geometry. These non-singular transitions provide a mechanism through which a probe or a ``watcher,'' used to define a local measure, can safely evolve through the bounce and geodesics can be smoothly extended from anti-deSitter to de-Sitter vacua.

  13. Re-emergent human adenovirus genome type 7d caused an acute respiratory disease outbreak in Southern China after a twenty-one year absence.

    PubMed

    Zhao, Suhui; Wan, Chengsong; Ke, Changwen; Seto, Jason; Dehghan, Shoaleh; Zou, Lirong; Zhou, Jie; Cheng, Zetao; Jing, Shuping; Zeng, Zhiwei; Zhang, Jing; Wan, Xuan; Wu, Xianbo; Zhao, Wei; Zhu, Li; Seto, Donald; Zhang, Qiwei

    2014-12-08

    Human adenoviruses (HAdVs) are highly contagious pathogens causing acute respiratory disease (ARD), among other illnesses. Of the ARD genotypes, HAdV-7 presents with more severe morbidity and higher mortality than the others. We report the isolation and identification of a genome type HAdV-7d (DG01_2011) from a recent outbreak in Southern China. Genome sequencing, phylogenetic analysis, and restriction endonuclease analysis (REA) comparisons with past pathogens indicate HAdV-7d has re-emerged in Southern China after an absence of twenty-one years. Recombination analysis reveals this genome differs from the 1950s-era prototype and vaccine strains by a lateral gene transfer, substituting the coding region for the L1 52/55 kDa DNA packaging protein from HAdV-16. DG01_2011 descends from both a strain circulating in Southwestern China (2010) and a strain from Shaanxi causing a fatality and outbreak (Northwestern China; 2009). Due to the higher morbidity and mortality rates associated with HAdV-7, the surveillance, identification, and characterization of these strains in population-dense China by REA and/or whole genome sequencing are strongly indicated. With these accurate identifications of specific HAdV types and an epidemiological database of regional HAdV pathogens, along with the HAdV genome stability noted across time and space, the development, availability, and deployment of appropriate vaccines are needed.

  14. Computational and anti-tumor studies of 7a-Aza-B-homostigmast-5-eno [7a, 7-d] tetrazole-3β-yl chloride

    NASA Astrophysics Data System (ADS)

    Alam, Mahboob; Alam, Mohammad Jane; Nami, Shahab A. A.; Lee, Dong-Ung; Azam, Mohammad; Ahmad, Shabbir

    2016-03-01

    The present paper reports the detailed computational study including molecular docking of a biologically active steroidal tetrazole, 7a-Aza-B-homostigmast-5-eno [7a,7-d] tetrazole-3β-yl chloride. The molecular structure, IR and NMR (13C and 1H) spectra of the tetrazole were interpreted by comparing the experimental results with the theoretical, B3LYP/6-311G(d,p) calculations. The vibrational bands appearing in the FTIR are assigned with great accuracy using animated modes. Molecular properties like HOMO-LUMO analysis, chemical reactivity descriptors, MEP mapping, dipole moment and natural atomic charges have been presented at the same level of theory. The theoretical results are found in good correlation with the experimental data. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots. The in vitro anti-tumor activity of 7a-Aza-B-homostigmast-5-eno [7a,7-d] tetrazole-3β-yl chloride has also been carried out against five human tumor cell lines. Doxorubicin is used as a standard drug for the in vitro anti-tumor screening.

  15. DFT, Hirshfeld surfaces, spectral and in vivo cytotoxic studies of 7a-Aza-B-homostigmast-5-eno [7a,7-d] tetrazole

    NASA Astrophysics Data System (ADS)

    Alam, Mahboob; Alam, Mohammad Jane; Nami, Shahab A. A.; Khan, Mohd Shoeb; Ahmad, Shabbir; Lee, Dong-Ung

    2015-11-01

    The DFT (B3LYP) calculations on a synthetic steroidal molecule 7a-Aza-B-homostigmast-5-eno [7a,7-d] tetrazole, C29H48N4, have been performed. The molecular structure, IR and NMR (13C and 1H) spectra of the present compound were interpreted using experiments (XRD, FTIR, NMR) as well as theoretical, B3LYP/6-311 + G(2d,p), calculations. The vibrational bands appearing in FTIR are assigned with great accuracy using animated modes. Molecular properties like HOMO-LUMO analysis, chemical reactivity descriptors, MEP mapping, dipole moment and Mullikan's atomic charges have been presented at the same level of theory. The theoretical results are found in good correlation with experimental data. Moreover, the Hirshfeld analysis was carried out to ascertain the secondary interactions and associated 2D fingerprint plots. The in vivo cytotoxicity of 7a-Aza-B-homostigmast-5-eno [7a,7-d] has also been carried out against brine shrimp nauplii by lethality bioassay.

  16. Optimisation of broiler chicken responses from 0 to 7 d of age to dietary leucine, isoleucine and valine using Taguchi and mathematical methods.

    PubMed

    Sedghi, M; Golian, A; Kolahan, F; Afsar, A

    2015-01-01

    Three experiments were conducted to evaluate the applicability of the Taguchi method (TM) and optimisation algorithms to optimise the branch chain amino acids (BCAA) requirements in 0 to 7 d broiler chicks. In the first experiment, the standardised digestible (SID) amino acids and apparent metabolisable energy (AME) values of maize, wheat and soya bean meal were evaluated. In the second experiment, three factors including leucine (Leu), isoleucine (Ile) and valine (Val), each at 4 levels, were selected, and an orthogonal array layout of L16 (4(3)) using TM was performed. After data collection, optimisation of average daily gain (ADG) and feed conversion ratio (FCR) were obtained using TM. The multiobjective genetic algorithm (MOGA) and random search algorithm (RSA) were also applied to predict the optimal combination of BCAA for broiler performance. In the third experiment, a growth study was conducted to evaluate the applicability of obtained optimum BCAA requirements data by TM, MOGA and RSA, and results were compared with those of birds fed with a diet formulated according to Ross 308 recommendations. In the second experiment, the TM resulted in 13.45 g/kg SID Leu, 8.5 g/kg SID Ile and 10.45 g/kg SID Val as optimum level for maximum ADG (21.57 g/bird/d) and minimum FCR (1.11 g feed/g gain) in 0- to 7-d-old broiler chickens. MOGA predicted the following combinations: SID Leu = 14.8, SID Ile = 9.1 and SID Val = 10.3 for maximum ADG (22.05) and minimum FCR (1.11). The optimisation using RSA predicted Leu = 16.0, Ile = 9.5 and Val = 10.2 for maximum ADG (22.67), and Leu = 15.5, Ile = 9.0 and Val = 10.4 to achieve minimum FCR (1.08). The validation experiment confirmed that TM, MOGA and RSA yielded optimum determination of dietary amino acid requirements and improved ADG and FCR as compared to Aviagen recommendations. However, based on the live animal validation trial, MOGA and RSA overpredicted the optimum requirement as compared to TM. In

  17. Development and Molecular Cytogenetic Identification of a Novel Wheat–Leymus mollis Lm#7Ns (7D) Disomic Substitution Line with Stripe Rust Resistance

    PubMed Central

    Yang, Xiaofei; Wang, Changyou; Li, Xin; Chen, Chunhuan; Tian, Zengrong; Wang, Yajuan; Ji, Wanquan

    2015-01-01

    Leymus mollis (2n = 4x = 28, NsNsXmXm) possesses novel and important genes for resistance against multi-fungal diseases. The development of new wheat—L. mollis introgression lines is of great significance for wheat disease resistance breeding. M11003-3-1-15-8, a novel disomic substitution line of common wheat cv. 7182 –L. mollis, developed and selected from the BC1F5 progeny between wheat cv. 7182 and octoploid Tritileymus M47 (2n = 8x = 56, AABBDDNsNs), was characterized by morphological and cytogenetic identification, analysis of functional molecular markers, genomic in situ hybridization (GISH), sequential fluorescence in situ hybridization (FISH)—genomic in situ hybridization (GISH) and disease resistance evaluation. Cytological observations suggested that M11003-3-1-15-8 contained 42 chromosomes and formed 21 bivalents at meiotic metaphase I. The GISH investigations showed that line contained 40 wheat chromosomes and a pair of L. mollis chromosomes. EST-STS multiple loci markers and PLUG (PCR-based Landmark Unique Gene) markers confirmed that the introduced L. mollis chromosomes belonged to homoeologous group 7, it was designated as Lm#7Ns. While nulli-tetrasomic and sequential FISH-GISH analysis using the oligonucleotide Oligo-pSc119.2 and Oligo-pTa535 as probes revealed that the wheat 7D chromosomes were absent in M11003-3-1-15-8. Therefore, it was deduced that M11003-3-1-15-8 was a wheat–L. mollis Lm#7Ns (7D) disomic substitution line. Field disease resistance demonstrated that the introduced L. mollis chromosomes Lm#7Ns were responsible for the stripe rust resistance at the adult stage. Moreover, M11003-3-1-15-8 had a superior numbers of florets. The novel disomic substitution line M11003-3-1-15-8, could be exploited as an important genetic material in wheat resistance breeding programs and genetic resources. PMID:26465140

  18. Static and non-static black holes with the Liouville mode

    NASA Astrophysics Data System (ADS)

    Moskalets, T. M.; Nurmagambetov, A. J.

    2017-03-01

    We present a new class of static and non-static quasi-spherical black hole solutions in four-dimensional Minkowski and Anti-de Sitter spaces and briefly discuss its employing in the Gauge/Gravity duality.

  19. Holography and Colliding gravitational shock waves in asymptotically AdS5 spacetime.

    PubMed

    Chesler, Paul M; Yaffe, Laurence G

    2011-01-14

    Using holography, we study the collision of planar shock waves in strongly coupled N=4 supersymmetric Yang-Mills theory. This requires the numerical solution of a dual gravitational initial value problem in asymptotically anti-de Sitter spacetime.

  20. AdS/QCD holographic wave function for the ρ meson and diffractive ρ meson electroproduction.

    PubMed

    Forshaw, J R; Sandapen, R

    2012-08-24

    We show that anti-de Sitter/quantum chromodynamics generates predictions for the rate of diffractive ρ-meson electroproduction that are in agreement with data collected at the Hadron Electron Ring Accelerator electron-proton collider.

  1. Nonivamide enhances miRNA let-7d expression and decreases adipogenesis PPARγ expression in 3T3-L1 cells.

    PubMed

    Rohm, Barbara; Holik, Ann-Katrin; Kretschy, Nicole; Somoza, Mark M; Ley, Jakob P; Widder, Sabine; Krammer, Gerhard E; Marko, Doris; Somoza, Veronika

    2015-06-01

    Red pepper and its major pungent principle, capsaicin (CAP), have been shown to be effective anti-obesity agents by reducing energy intake, enhancing energy metabolism, decreasing serum triacylglycerol content, and inhibiting adipogenesis via activation of the transient receptor potential cation channel subfamily V member 1 (TRPV1). However, the binding of CAP to the TRPV1 receptor is also responsible for its pungent sensation, strongly limiting its dietary intake. Here, the effects of a less pungent structural CAP-analog, nonivamide, on adipogenesis and underlying mechanisms in 3T3-L1 cells were studied. Nonivamide was found to reduce mean lipid accumulation, a marker of adipogenesis, to a similar extent as CAP, up to 10.4% (P < 0.001). Blockage of the TRPV1 receptor with the specific inhibitor trans-tert-butylcyclohexanol revealed that the anti-adipogenic activity of nonivamide depends, as with CAP, on TRPV1 receptor activation. In addition, in cells treated with nonivamide during adipogenesis, protein levels of the pro-adipogenic transcription factor peroxisome-proliferator activated receptor γ (PPARγ) decreased. Results from miRNA microarrays and digital droplet PCR analysis demonstrated an increase in the expression of the miRNA mmu-let-7d-5p, which has been associated with decreased PPARγ levels.

  2. Search for the origin of giant Tc suppression in YBa 2Cu 3O 7- d doped simultaneously with Fe and Zn

    NASA Astrophysics Data System (ADS)

    Ogale, S. B.; Gapchup, K. M.; Lele, Pramada; Choughule, D. D.; Chikate, R. C.; Marest, G.

    1996-02-01

    In a recent paper [S.B. Ogale et al., Solid State Commun 89 (1994) 1] we reported that the superconducting transition temperature ( Tc) is suppressed drastically in YBa 2Cu 3O 7- d (YBCO) doped simultaneously with Fe and Zn as compared to an equivalent total doping of Zn or Fe, on the higher side of dopant concentration (approximately 3% or more substitution at Cu sites). In this paper, we report the results of our studies on this co-doped system, performed using the techniques of Mössbauer spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and iodometry, to explore the origin of the reported observation. The Tc suppression appears to be caused by a drop in the concentration of mobile holes in the CuO 2 planes as well as to be due to a reduced dimensionality of the system resulting from the suppression of the order parameter between the CuO 2 planes by the Fe atoms.

  3. Born-Infeld gravity in three dimensions

    SciTech Connect

    Alishahiha, Mohsen; Naseh, Ali; Soltanpanahi, Hesam

    2010-07-15

    In this paper we explore different aspects of three dimensional Born-Infeld as well as Born-Infeld-Chern-Simons gravity. We show that the models have anti-de Sitter and anti-de Sitter wave vacuum solutions. Moreover, we observe that although Born-Infeld-Chern-Simons gravity admits a logarithmic solution, Born-Infeld gravity does not, though it has a limiting logarithmic solution as we approach the critical point.

  4. On the stability of dyons and dyonic black holes in Einstein-Yang-Mills theory

    NASA Astrophysics Data System (ADS)

    Nolan, Brien C.; Winstanley, Elizabeth

    2016-02-01

    We investigate the stability of four-dimensional dyonic soliton and black hole solutions of {su}(2) Einstein-Yang-Mills theory in anti-de Sitter space. We prove that, in a neighbourhood of the embedded trivial (Schwarzschild-)anti-de Sitter solution, there exist non-trivial dyonic soliton and black hole solutions of the field equations which are stable under linear, spherically symmetric, perturbations of the metric and non-Abelian gauge field.

  5. Static and rotating solutions for vector-Galileon theories

    NASA Astrophysics Data System (ADS)

    Cisterna, Adolfo; Hassaine, Mokhtar; Oliva, Julio; Rinaldi, Massimiliano

    2016-11-01

    We consider a particular truncation of the generalized Proca field theory in four dimensions for which we construct static and axisymmetric rotating black hole "stealth solutions," namely solutions with (anti) de Sitter or Kerr metric but nontrivial vector field. The static configuration is promoted to a backreacting black hole with asymptotic (anti) de Sitter behavior by turning on a nonlinear electrodynamic source given as a fixed power of the Maxwell invariant. Finally we extend our solutions to arbitrary dimensions.

  6. Modelling duality between bound and resonant meson spectra by means of free quantum motions on the de Sitter space-time dS4

    NASA Astrophysics Data System (ADS)

    Kirchbach, M.; Compean, C. B.

    2016-07-01

    The real parts of the complex squared energies defined by the resonance poles of the transfer matrix of the Pöschl-Teller barrier, are shown to equal the squared energies of the levels bound within the trigonometric Scarf well potential. By transforming these potentials into parts of the Laplacians describing free quantum motions on the mutually orthogonal open-time-like hyperbolic-, and closed-space-like spherical geodesics on the conformally invariant de Sitter space-time, dS4, the conformal symmetries of these interactions are revealed. On dS4 the potentials under consideration naturally relate to interactions within colorless two-body systems and to cusped Wilson loops. In effect, with the aid of the dS4 space-time as unifying geometry, a conformal symmetry based bijective correspondence (duality) between bound and resonant meson spectra is established at the quantum mechanics level and related to confinement understood as color charge neutrality. The correspondence allows to link the interpretation of mesons as resonance poles of a scattering matrix with their complementary description as states bound by an instantaneous quark interaction and to introduce a conformal symmetry based classification scheme of mesons. As examples representative of such a duality we organize in good agreement with data 71 of the reported light flavor mesons with masses below ˜ 2350 MeV into four conformal families of particles placed on linear f0, π , η , and a0 resonance trajectories, plotted on the ℓ/ M plane. Upon extending the sec2 χ by a properly constructed conformal color dipole potential, shaped after a tangent function, we predict the masses of 12 "missing" mesons. We furthermore notice that the f0 and π trajectories can be viewed as chiral partners, same as the η and a0 trajectories, an indication that chiral symmetry for mesons is likely to be realized in terms of parity doubled conformal multiplets rather than, as usually assumed, only in terms of parity

  7. Loss of MYC and E-box3 binding contributes to defective MYC-mediated transcriptional suppression of human MC-let-7a-1~let-7d in glioblastoma

    PubMed Central

    Wang, Zifeng; Lin, Sheng; Zhang, Ji; Xu, Zhenhua; Xiang, Yu; Yao, Hong; Ge, Lei; Xie, Dan; Kung, Hsiang-fu; Lu, Gang; Poon, Wai Sang; Liu, Quentin; Lin, Marie Chia-mi

    2016-01-01

    Previously, we reported that MYC oncoprotein down-regulates the transcription of human MC-let-7a-1~let-7d microRNA cluster in hepatocarcinoma (HCC). Surprisingly, in silico analysis indicated that let-7 miRNA expression levels are not reduced in glioblastoma (GBM). Here we investigated the molecular basis of this differential expression. Using human GBM U87 and U251 cells, we first demonstrated that forced over-expression of MYC indeed could not down-regulate the expression of human MC-let-7a-1~let-7d microRNA cluster in GBM. Furthermore, analysis of MC-let-7a-1~let-7d promoter in GBM indicated that MYC failed to inhibit the promoter activity. Pearson's correlation and Linear Regression analysis using the expression data from GSE55092 (HCC) and GSE4290 (GBM) demonstrated a converse relationship of MC-let-7a-1~let-7d and MYC only in HCC but not in GBM. To understand the underlying mechanisms, we examined whether MYC could bind to the non-canonical E-box 3 located in the promoter of MC-let-7a-1~let-7d. Results from both chromatin immune-precipitation (ChIP) and super-shift assays clearly demonstrated the loss of MYC and E-box 3 binding in GBM, suggesting for the first time that a defective MYC and E-box3 binding in GBM is responsible for the differential MYC mediated transcriptional inhibition of MC-let-7a-1~let-7d and potentially other tumor suppressors. MYC and let-7 are key oncoprotein and tumor suppressor, respectively. Understanding the molecular mechanisms of their regulations will provide new insight and have important implications in the therapeutics of GBM as well as other cancers. PMID:27409345

  8. Loss of MYC and E-box3 binding contributes to defective MYC-mediated transcriptional suppression of human MC-let-7a-1~let-7d in glioblastoma.

    PubMed

    Wang, Zifeng; Lin, Sheng; Zhang, Ji; Xu, Zhenhua; Xiang, Yu; Yao, Hong; Ge, Lei; Xie, Dan; Kung, Hsiang-Fu; Lu, Gang; Poon, Wai Sang; Liu, Quentin; Lin, Marie Chia-Mi

    2016-08-30

    Previously, we reported that MYC oncoprotein down-regulates the transcription of human MC-let-7a-1~let-7d microRNA cluster in hepatocarcinoma (HCC). Surprisingly, in silico analysis indicated that let-7 miRNA expression levels are not reduced in glioblastoma (GBM). Here we investigated the molecular basis of this differential expression. Using human GBM U87 and U251 cells, we first demonstrated that forced over-expression of MYC indeed could not down-regulate the expression of human MC-let-7a-1~let-7d microRNA cluster in GBM. Furthermore, analysis of MC-let-7a-1~let-7d promoter in GBM indicated that MYC failed to inhibit the promoter activity. Pearson's correlation and Linear Regression analysis using the expression data from GSE55092 (HCC) and GSE4290 (GBM) demonstrated a converse relationship of MC-let-7a-1~let-7d and MYC only in HCC but not in GBM. To understand the underlying mechanisms, we examined whether MYC could bind to the non-canonical E-box 3 located in the promoter of MC-let-7a-1~let-7d. Results from both chromatin immune-precipitation (ChIP) and super-shift assays clearly demonstrated the loss of MYC and E-box 3 binding in GBM, suggesting for the first time that a defective MYC and E-box3 binding in GBM is responsible for the differential MYC mediated transcriptional inhibition of MC-let-7a-1~let-7d and potentially other tumor suppressors. MYC and let-7 are key oncoprotein and tumor suppressor, respectively. Understanding the molecular mechanisms of their regulations will provide new insight and have important implications in the therapeutics of GBM as well as other cancers.

  9. Factors associated with nutritional decline in hospitalised medical and surgical patients admitted for 7 d or more: a prospective cohort study.

    PubMed

    Allard, Johane P; Keller, Heather; Teterina, Anastasia; Jeejeebhoy, Khursheed N; Laporte, Manon; Duerksen, Donald R; Gramlich, Leah; Payette, Helene; Bernier, Paule; Davidson, Bridget; Lou, Wendy

    2015-11-28

    This prospective cohort study was conducted in eighteen Canadian hospitals with the aim of examining factors associated with nutritional decline in medical and surgical patients. Nutritional decline was defined based on subjective global assessment (SGA) performed at admission and discharge. Data were collected on demographics, medical information, food intake and patients' satisfaction with nutrition care and meals during hospitalisation; 424 long-stay (≥7 d) patients were included; 38% of them had surgery; 51% were malnourished at admission (SGA B or C); 37% had in-hospital changes in SGA; 19·6% deteriorated (14·6% from SGA A to B/C and 5% from SGA B to C); 17·4% improved (10·6% from SGA B to A, 6·8% from SGA C to B/A); and 63·0 % patients were stable (34·4% were SGA A, 21·3% SGA B, 7·3% SGA C). One SGA C patient had weight loss ≥5%, likely due to fluid loss and was designated as stable. A subset of 364 patients with admission SGA A and B was included in the multiple logistic regression models to determine factors associated with nutritional decline. After controlling for SGA at admission and the presence of a surgical procedure, lower admission BMI, cancer, two or more diagnostic categories, new in-hospital infection, reduced food intake, dissatisfaction with food quality and illness affecting food intake were factors significantly associated with nutritional decline in medical patients. For surgical patients, only male sex was associated with nutritional decline. Factors associated with nutritional decline are different in medical and surgical patients. Identifying these factors may assist nutritional care.

  10. Investigation of Finsler geometry as a generalization to curved spacetime of Planck-scale-deformed relativity in the de Sitter case

    NASA Astrophysics Data System (ADS)

    Lobo, Iarley P.; Loret, Niccoló; Nettel, Francisco

    2017-02-01

    Over the last few years, Planck-scale modifications to the dispersion relation of particles have been deeply studied for the possibility to formulate some phenomenology of Planckian effects in astrophysical and cosmological frameworks. There are some indications [F. Girelli, S. Liberati, and L. Sindoni, Phys. Rev. D 75, 064015 (2007), 10.1103/PhysRevD.75.064015] that Finsler geometry can provide some generalization of Riemannian geometry which may allow us to account for the nontrivial (Planckian) structure of the relativistic particles' configuration space. We investigate the possibility to formalize Planck-scale deformations to relativistic models in curved spacetime, within the framework of Finsler geometry. We take into account the general strategy of analysis of dispersion relations modifications in curved spacetimes proposed in [G. Rosati, G. Amelino-Camelia, A. Marciano, and M. Matassa, Phys. Rev. D 92, 124042 (2015), 10.1103/PhysRevD.92.124042], generalizing to the de Sitter case the results obtained in [G. Amelino-Camelia, L. Barcaroli, G. Gubitosi, S. Liberati, and N. Loret, Phys. Rev. D 90, 125030 (2014), 10.1103/PhysRevD.90.125030] for deformed relativistic particle kinematics in flat spacetime using Finsler formalism.

  11. Randomized trial on the effects of a 7-d low-glycemic diet and exercise intervention on insulin resistance in older obese humans123

    PubMed Central

    Solomon, Thomas PJ; Haus, Jacob M; Kelly, Karen R; Cook, Marc D; Riccardi, Michelle; Rocco, Michael; Kashyap, Sangeeta R; Barkoukis, Hope

    2009-01-01

    Background: The optimal combination of diet and exercise that produces the greatest reversal of obesity-related insulin resistance is unknown. Objectives: We examined the effects of a combined 7-d low–glycemic index (low-GI) diet and exercise training intervention on insulin sensitivity in older obese humans. Design: Participants [n = 32; mean (±SEM) age: 66 ± 1 y; body mass index (in kg/m2): 33.8 ± 0.7] were randomly assigned to a parallel, double-blind, controlled-feeding trial and underwent supervised aerobic exercise (EX; 60 min/d at 80–85% maximum heart rate) in combination with either a low-GI (LoGI + EX: 41.1 ± 0.4) or a high-GI (HiGI + EX: 80.9 ± 0.6) diet. All meals were provided and were isocaloric to individual energy requirements. Insulin sensitivity and hepatic glucose production were assessed with a 40–mU ⋅ m−2 · min−1 hyperinsulinemic euglycemic clamp combined with a [6,6-2H2]-glucose infusion. Results: After the intervention, small decreases were observed in body weight (−1.6 ± 0.2 kg; P < 0.0001) and fat mass (−1.7 ± 0.9%; P = 0.004) in both groups. Maximal aerobic capacity (V̇O2max) also improved slightly (0.06 ± 0.02 L/min; P = 0.004). Resting systolic blood pressure, fasting glucose, insulin, triglycerides, and cholesterol all decreased after the study (all P < 0.05). Larger changes in systolic blood pressure and V̇O2max were seen in the LoGI + EX group. Insulin-stimulated glucose disposal (P < 0.001), insulin suppression of hepatic glucose production (P = 0.004), and postabsorptive fat oxidation (P = 0.03) improved equally in both groups after the intervention. Conclusions: These findings suggest that the metabolic improvements after short-term exercise training in older obese individuals are dependent on increased physical activity and are not influenced by a low-GI diet. However, a low-GI diet has added benefit in alleviating hypertension, thus reducing the risk of diabetic and vascular complications. PMID:19793849

  12. MONOPOLES AND DYONS IN THE PURE EINSTEIN YANG MILLS THEORY

    SciTech Connect

    HOSOTANI,Y.; BJORAKER,J.

    1999-08-16

    In the pure Einstein-Yang-Mills theory in four dimensions there exist monopole and dyon solutions. The spectrum of the solutions is discrete in asymptotically flat or de Sitter space, whereas it is continuous in asymptotically anti-de Sitter space. The solutions are regular everywhere and specified with their mass, and non-Abelian electric and magnetic charges. In asymptotically anti-de Sitter space a class of monopole solutions have no node in non-Abelian magnetic fields, and are stable against spherically symmetric perturbations.

  13. Lutein ester profile in wheat and tritordeum can be modulated by temperature: Evidences for regioselectivity and fatty acid preferential of enzymes encoded by genes on chromosomes 7D and 7H(ch).

    PubMed

    Mattera, M G; Hornero-Méndez, D; Atienza, S G

    2017-03-15

    The increase of lutein retention through the food chain is desirable for wheat breeding. Lutein esters are more stable than free lutein during post-harvest storage and two loci on chromosomes 7D and 7H(ch) are important for esterification. We investigated the effect of temperature during grain filling on carotenoid accumulation and lutein ester profile including fatty acid selectivity (palmitic vs. linoleic) and regioselectivity (esterification at positions 3 vs. 3'). Three different temperature regimes were assayed (controlled, semi-controlled and non-controlled). Lutein esters were more stable than free carotenoids in vivo and the enzymes encoded by chromosomes 7H(ch) and 7D are complementary. Indeed, they show differential preferences for the fatty acid (palmitic and linoleic, respectively) and regioselectivity (3 and 3', respectively). Besides, H. chilense has additional genes for esterification. Finally, the increase of temperature favoured the accumulation of lutein esters with linoleic acid and the synthesis of regioisomers at position 3'.

  14. Evolution of segmented strings

    NASA Astrophysics Data System (ADS)

    Gubser, Steven S.

    2016-11-01

    I explain how to evolve segmented strings in de Sitter and anti-de Sitter spaces of any dimension in terms of forward-directed null displacements. The evolution is described entirely in terms of discrete hops which do not require a continuum spacetime. Moreover, the evolution rule is purely algebraic, so it can be defined not only on ordinary real de Sitter and anti-de Sitter but also on the rational points of the quadratic equations that define these spaces. For three-dimensional anti-de Sitter space, a simpler evolution rule is possible that descends from the Wess-Zumino-Witten equations of motion. In this case, one may replace three-dimensional anti-de Sitter space by a noncompact discrete subgroup of S L (2 ,R ) whose structure is related to the Pell equation. A discrete version of the Bañados-Teitelboim-Zanelli (BTZ) black hole can be constructed as a quotient of this subgroup. This discrete black hole avoids the firewall paradox by a curious mechanism: even for large black holes, there are no points inside the horizon until one reaches the singularity.

  15. Supersymmetry Properties of AdS Supergravity Backgrounds

    NASA Astrophysics Data System (ADS)

    Beck, Samuel; Gutowski, Jan; Papadopoulos, George

    2017-01-01

    Anti-de Sitter supergravity backgrounds are of particular interest in light of the AdS/CFT correspondence, which relates them to dual conformal field theories on the boundary of the anti-de Sitter space. We have investigated the forms of the supersymmetries these backgrounds preserve by solving the Killing spinor equations on the anti-de Sitter components of these spaces. We have found that a supersymmetric AdSn background necessarily preserves 2⌊n/2⌋ k supersymmetries for n <= 4 and 2 ⌊n/2 ⌋ + 1 k supersymmetries for 4 < n <= 7 , k ∈N> 0 . Additionally, we have found that the Killing spinors of each background are exactly the zeroes of a Dirac-like operator constructed from the Killing spinor equations.

  16. Quantum probabilities for inflation from holography

    SciTech Connect

    Hartle, James B.; Hawking, S.W.; Hertog, Thomas E-mail: S.W.Hawking@damtp.cam.ac.uk

    2014-01-01

    The evolution of the universe is determined by its quantum state. The wave function of the universe obeys the constraints of general relativity and in particular the Wheeler-DeWitt equation (WDWE). For non-zero Λ, we show that solutions of the WDWE at large volume have two domains in which geometries and fields are asymptotically real. In one the histories are Euclidean asymptotically anti-de Sitter, in the other they are Lorentzian asymptotically classical de Sitter. Further, the universal complex semiclassical asymptotic structure of solutions of the WDWE implies that the leading order in h-bar quantum probabilities for classical, asymptotically de Sitter histories can be obtained from the action of asymptotically anti-de Sitter configurations. This leads to a promising, universal connection between quantum cosmology and holography.

  17. Zeta functions in brane world cosmology

    NASA Astrophysics Data System (ADS)

    Flachi, Antonino; Knapman, Alan; Naylor, Wade; Sasaki, Misao

    2004-12-01

    We present a calculation of the zeta function and of the functional determinant for a Laplace-type differential operator, corresponding to a scalar field in a higher-dimensional deSitter brane background, which consists of a higher-dimensional anti deSitter bulk spacetime bounded by a deSitter section, representing a brane. Contrary to the existing examples, which all make use of conformal transformations, we evaluate the zeta function working directly with the higher-dimensional wave operator. We also consider a generic mass term and coupling to curvature, generalizing previous results. The massless, conformally coupled case is obtained as a limit of the general result and compared with known calculations. In the limit of large anti deSitter radius, the zeta determinant for the ball is recovered in perfect agreement with known expressions, providing an interesting check of our result and an alternative way of obtaining the ball determinant.

  18. A study of planar structures formed on the modified Al2O3 surfaces determining the topology of superconducting elements during YBa2Cu3O7- d deposition

    NASA Astrophysics Data System (ADS)

    Masterov, D. V.; Pavlov, S. A.; Parafin, A. E.; Yunin, P. A.

    2016-06-01

    We investigate the structural and electrical properties of planar superconducting structures based on the YBa2Cu3O7- d (YBCO) epitaxial films obtained by preliminary modification of the substrate surface. A special master mask was formed on the substrates, so that, at the standard YBCO film deposition onto such a substrate, an insulator layer grew in the modified areas and a superconducting film, in the unmodified ones. Thus, the planar superconducting structure of a desired topology was formed, and the YBCO deposition finished the process. Using this technique, YBCO bridges with widths of 4, 10, and 50 μm on films of different thicknesses and a planar inductive coil were formed. The superconducting transition temperature of the bridges was about 90 K, and the critical current density at a temperature of 77 K was up to 3 MA/cm2. The Q factor of the planar inductive coil at a frequency of 85 MHz was 53000 at a temperature of 77 K.

  19. Full-dimensional quantum calculations of the dissociation energy, zero-point, and 10 K properties of H7+/D7+ clusters using an ab initio potential energy surface.

    PubMed

    Barragán, Patricia; Pérez de Tudela, Ricardo; Qu, Chen; Prosmiti, Rita; Bowman, Joel M

    2013-07-14

    Diffusion Monte Carlo (DMC) and path-integral Monte Carlo computations of the vibrational ground state and 10 K equilibrium state properties of the H7 (+)/D7 (+) cations are presented, using an ab initio full-dimensional potential energy surface. The DMC zero-point energies of dissociated fragments H5 (+)(D5 (+))+H2(D2) are also calculated and from these results and the electronic dissociation energy, dissociation energies, D0, of 752 ± 15 and 980 ± 14 cm(-1) are reported for H7 (+) and D7 (+), respectively. Due to the known error in the electronic dissociation energy of the potential surface, these quantities are underestimated by roughly 65 cm(-1). These values are rigorously determined for first time, and compared with previous theoretical estimates from electronic structure calculations using standard harmonic analysis, and available experimental measurements. Probability density distributions are also computed for the ground vibrational and 10 K state of H7 (+) and D7 (+). These are qualitatively described as a central H3 (+)/D3 (+) core surrounded by "solvent" H2/D2 molecules that nearly freely rotate.

  20. Nonlinear W∞ as asymptotic symmetry of three-dimensional higher spin AdS gravity

    NASA Astrophysics Data System (ADS)

    Henneaux, Marc; Rey, Soo-Jong

    2010-12-01

    We investigate the asymptotic symmetry algebra of (2+1)-dimensional higher spin, anti-de Sitter gravity. We use the formulation of the theory as a Chern-Simons gauge theory based on the higher spin algebra hs(1 , 1). Expanding the gauge connection around asymptotically anti-de Sitter spacetime, we specify consistent boundary conditions on the higher spin gauge fields. We then study residual gauge transformation, the corresponding surface terms and their Poisson bracket algebra. We find that the asymptotic symmetry algebra is a nonlinearly realized W ∞ algebra with classical central charges. We discuss implications of our results to quantum gravity and to various situations in string theory.

  1. Stringy stability of charged dilaton black holes with flat event horizon

    SciTech Connect

    Ong, Yen Chin; Chen, Pisin

    2015-01-15

    Electrically charged black holes with flat event horizon in anti-de Sitter space have received much attention due to various applications in Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, from modeling the behavior of quark-gluon plasma to superconductor. Critical to the physics on the dual field theory is the fact that when embedded in string theory, black holes in the bulk may become vulnerable to instability caused by brane pair-production. Since dilation arises naturally in the context of string theory, we study the effect of coupling dilation to Maxwell field on the stability of flat charged AdS black holes.

  2. Marginally trapped submanifolds in Lorentzian space forms and in the Lorentzian product of a space form by the real line

    SciTech Connect

    Anciaux, Henri; Godoy, Yamile

    2015-02-15

    We give local, explicit representation formulas for n-dimensional spacelike submanifolds which are marginally trapped in the Minkowski space ℝ{sub 1}{sup n+2}, the de Sitter space dS{sup n+2}, the anti-de Sitter space AdS{sup n+2} and the Lorentzian products S{sup n+1} × ℝ and ℍ{sup n+1} × ℝ of the sphere and the hyperbolic space by the real line.

  3. Scalar field evolution in Gauss-Bonnet black holes

    SciTech Connect

    Abdalla, E.; Konoplya, R.A.; Molina, C.

    2005-10-15

    It is presented a thorough analysis of scalar perturbations in the background of Gauss-Bonnet, Gauss-Bonnet-de Sitter and Gauss-Bonnet-anti-de Sitter black hole spacetimes. The perturbations are considered both in frequency and time domain. The dependence of the scalar field evolution on the values of the cosmological constant {lambda} and the Gauss-Bonnet coupling {alpha} is investigated. For Gauss-Bonnet and Gauss-Bonnet-de Sitter black holes, at asymptotically late times either power-law or exponential tails dominate, while for Gauss-Bonnet-anti-de Sitter black hole, the quasinormal modes govern the scalar field decay at all times. The power-law tails at asymptotically late times for odd-dimensional Gauss-Bonnet black holes does not depend on {alpha}, even though the black hole metric contains {alpha} as a new parameter. The corrections to quasinormal spectrum due to Gauss-Bonnet coupling is not small and should not be neglected. For the limit of near extremal value of the (positive) cosmological constant and pure de Sitter and anti-de Sitter modes in Gauss-Bonnet gravity we have found analytical expressions.

  4. The high-pressure phase diagram of synthetic epsomite (MgSO4·7H2O and MgSO4·7D2O) from ultrasonic and neutron powder diffraction measurements

    NASA Astrophysics Data System (ADS)

    Gromnitskaya, E. L.; Yagafarov, O. F.; Lyapin, A. G.; Brazhkin, V. V.; Wood, I. G.; Tucker, M. G.; Fortes, A. D.

    2013-03-01

    We present an ultrasonic and neutron powder diffraction study of crystalline MgSO4·7H2O (synthetic epsomite) and MgSO4·7D2O under pressure up to ~3 GPa near room temperature and up to ~2 GPa at lower temperatures. Both methods provide complementary data on the phase transitions and elasticity of magnesium sulphate heptahydrate, where protonated and deuterated counterparts exhibit very similar behaviour and properties. Under compression in the declared pressure intervals, we observed three different sequences of phase transitions: between 280 and 295 K, phase transitions occurred at approximately 1.4, 1.6, and 2.5 GPa; between 240 and 280 K, only a single phase transition occurred; below 240 K, there were no phase transformations. Overall, we have identified four new phase fields at high pressure, in addition to that of the room-pressure orthorhombic structure. Of these, we present neutron powder diffraction data obtained in situ in the three phase fields observed near room temperature. We present evidence that these high-pressure phase fields correspond to regions where MgSO4·7H2O decomposes to a lower hydrate by exsolving water. Upon cooling to liquid nitrogen temperatures, the ratio of shear modulus G to bulk modulus B increases and we observe elastic softening of both moduli with pressure, which may be a precursor to pressure-induced amorphization. These observations may have important consequences for modelling the interiors of icy planetary bodies in which hydrated sulphates are important rock-forming minerals, such as the large icy moons of Jupiter, influencing their internal structure, dynamics, and potential for supporting life.

  5. Conformally related massless fields in dS, AdS and Minkowski spaces

    SciTech Connect

    Huguet, E.; Queva, J.; Renaud, J.

    2006-04-15

    In this paper we write down the equation for a scalar conformally coupled field simultaneously for de Sitter (dS), anti-de Sitter (AdS), and Minkowski spacetimes in d dimensions. The curvature dependence appears in a very simple way through a conformal factor. As a consequence the process of curvature free limit, including wave functions limit and two-points functions, turns out to be a straightforward issue. We determine a set of modes, that we call de Sitter plane waves, which become ordinary plane waves when the curvature vanishes.

  6. 1+1 dimensional compactifications of string theory.

    PubMed

    Goheer, Naureen; Kleban, Matthew; Susskind, Leonard

    2004-05-14

    We argue that stable, maximally symmetric compactifications of string theory to 1+1 dimensions are in conflict with holography. In particular, the finite horizon entropies of the Rindler wedge in 1+1 dimensional Minkowski and anti-de Sitter space, and of the de Sitter horizon in any dimension, are inconsistent with the symmetries of these spaces. The argument parallels one made recently by the same authors, in which we demonstrated the incompatibility of the finiteness of the entropy and the symmetries of de Sitter space in any dimension. If the horizon entropy is either infinite or zero, the conflict is resolved.

  7. Distance between Quantum States and Gauge-Gravity Duality.

    PubMed

    Miyaji, Masamichi; Numasawa, Tokiro; Shiba, Noburo; Takayanagi, Tadashi; Watanabe, Kento

    2015-12-31

    We study a quantum information metric (or fidelity susceptibility) in conformal field theories with respect to a small perturbation by a primary operator. We argue that its gravity dual is approximately given by a volume of maximal time slice in an anti-de Sitter spacetime when the perturbation is exactly marginal. We confirm our claim in several examples.

  8. AdS collapse of a scalar field in higher dimensions

    SciTech Connect

    Jalmuzna, Joanna; Rostworowski, Andrzej; Bizon, Piotr

    2011-10-15

    We show that the weakly turbulent instability of anti-de Sitter space, recently found in P. Bizon and A. Rostworowski, Phys. Rev. Lett. 107, 031102 (2011) for 3+1-dimensional spherically symmetric Einstein-massless-scalar field equations with negative cosmological constant, is present in all dimensions d+1 for d{>=}3.

  9. Contraction-based classification of supersymmetric extensions of kinematical lie algebras

    SciTech Connect

    Campoamor-Stursberg, R.; Rausch de Traubenberg, M.

    2010-02-15

    We study supersymmetric extensions of classical kinematical algebras from the point of view of contraction theory. It is shown that contracting the supersymmetric extension of the anti-de Sitter algebra leads to a hierarchy similar in structure to the classical Bacry-Levy-Leblond classification.

  10. Supersymmetric Lorentz Chern-Simons terms coupled to supergravity

    SciTech Connect

    Nishino, Hitoshi; Rajpoot, Subhash

    2010-04-15

    We present supersymmetric Lorentz Chern-Simons terms coupled to anti-de Sitter supergravity in three dimensions with an arbitrary number of supersymmetries. As an application to higher dimensions, we present analogous supersymmetric Lorentz Chern-Simons terms coupled to N=1 supergravity in 11 dimensions.

  11. Conformal gravity from the AdS/CFT mechanism

    SciTech Connect

    Aros, Rodrigo; Romo, Mauricio; Zamorano, Nelson

    2007-03-15

    We explicitly calculate the induced gravity theory at the boundary of an asymptotically anti-de Sitter five dimensional Einstein gravity. We also display the action that encodes the dynamics of radial diffeomorphisms. It is found that the induced theory is a four dimensional conformal gravity plus a scalar field. This calculation confirms some previous results found by a different approach.

  12. Jerusalem lectures on black holes and quantum information

    NASA Astrophysics Data System (ADS)

    Harlow, D.

    2016-01-01

    These lectures give an introduction to the quantum physics of black holes, including recent developments based on quantum information theory such as the firewall paradox and its various cousins. An introduction is also given to holography and the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, focusing on those aspects which are relevant for the black hole information problem.

  13. Sitterly, Charlotte Emma Moore (1898-1990)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Astrophysicist and atomic physicist, worked with HENRY NORRIS RUSSELL at Princeton on binary stars and their masses. She worked at Mount Wilson with Charles E St John and HAROLD BABCOCK analysing the atomic lines in the sunspot spectrum. At the National Bureau of Standards and the Naval Research Laboratory she analysed laboratory data on the solar spectrum and the atomic data by which spectral li...

  14. Twin Paradox in de Sitter Spacetime

    ERIC Educational Resources Information Center

    Boblest, Sebastian; Muller, Thomas; Wunner, Gunter

    2011-01-01

    The "twin paradox" of special relativity offers the possibility of making interstellar flights within a lifetime. For very long journeys with velocities close to the speed of light, however, we have to take into account the expansion of the universe. Inspired by the work of Rindler on hyperbolic motion in curved spacetime, we study the worldline…

  15. de Sitter and double asymmetric brane worlds

    SciTech Connect

    Guerrero, Rommel; Rodriguez, R. Omar; Torrealba, Rafael

    2005-12-15

    Asymmetric brane worlds with dS expansion and static double kink topology are obtained from a recently proposed method and their properties are analyzed. These domain walls interpolate between two spacetimes with different cosmological constants. In the dynamic case, the vacua correspond to dS and AdS geometry, unlike the static case where they correspond to AdS background. We show that it is possible to confine gravity on such branes. In particular, the double-brane world hosts two different walls, so that the gravity is localized on one of them.

  16. The dS/dS Correspondence

    NASA Astrophysics Data System (ADS)

    Alishahiha, Mohsen; Karch, Andreas; Silverstein, Eva; Tong, David

    2004-12-01

    We present a holographic duality for the de Sitter static patch which consolidates basic features of its geometry and the behavior of gravity and brane probes, valid on timescales short compared to the decay or Poincare recurrence times. Namely de Sitter spacetime dSd(R) in d dimensions with curvature radius R is holographically dual to two conformal field theories on dSd-1(R), cut off at an energy scale 1/R where they couple to each other and to d - 1 dimensional gravity. As part of our analysis, we study brane probes in de Sitter and thermal Anti de Sitter spaces, and interpret the terms in the corresponding DBI action via strongly coupled thermal field theory. This provides a dual field theoretic interpretation of the fact that probes take forever to reach a horizon in general relativity.

  17. 19 CFR 4.7d - Container status messages.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... electronic data interchange system. There is no requirement that a carrier create or collect any CSMs under... any necessary modifications to the approved electronic data interchange system are not yet in place or... electronic equipment tracking system. (b) Events required to be reported. The following events must...

  18. 19 CFR 4.7d - Container status messages.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... electronic data interchange system. There is no requirement that a carrier create or collect any CSMs under... any necessary modifications to the approved electronic data interchange system are not yet in place or... electronic equipment tracking system. (b) Events required to be reported. The following events must...

  19. 19 CFR 4.7d - Container status messages.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... electronic data interchange system. There is no requirement that a carrier create or collect any CSMs under... any necessary modifications to the approved electronic data interchange system are not yet in place or... electronic equipment tracking system. (b) Events required to be reported. The following events must...

  20. 19 CFR 4.7d - Container status messages.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... electronic data interchange system. There is no requirement that a carrier create or collect any CSMs under... any necessary modifications to the approved electronic data interchange system are not yet in place or... electronic equipment tracking system. (b) Events required to be reported. The following events must...

  1. 19 CFR 4.7d - Container status messages.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... electronic data interchange system. There is no requirement that a carrier create or collect any CSMs under... any necessary modifications to the approved electronic data interchange system are not yet in place or... electronic equipment tracking system. (b) Events required to be reported. The following events must...

  2. The Singularity Problem in Brane Cosmology

    NASA Astrophysics Data System (ADS)

    Antoniadis, Ignatios; Cotsakis, Spiros

    2017-02-01

    We review results about the development and asymptotic nature of singularities in `brane-bulk' systems. These arise for warped metrics obeying the 5-dimensional Einstein equations with fluid-like sources, and including a brane 4-metric that is either Minkowski or de Sitter or Anti-de Sitter. We characterize all singular Minkowski brane solutions, and look for regular solutions with nonzero curvature. We briefly comment on matching solutions, energy conditions and finite Planck mass criteria for admissibility, and we briefly discuss the connection of these results to ambient theory.

  3. Bianchi-I cosmology from causal thermodynamics

    NASA Astrophysics Data System (ADS)

    Bittencourt, Eduardo; Gomes, Leandro G.; Klippert, Renato

    2017-02-01

    We investigate diagonal Bianchi-I spacetimes in the presence of viscous fluids by using the shear and the anisotropic pressure components as the basic variables, where the viscosity is driven by the (second-order) causal thermodynamics. A few exact solutions are presented, among which we mention the anisotropic versions of de Sitter/anti-de Sitter geometries as well as an asymptotically isotropic spacetime presenting an effectively constant cosmic acceleration without any cosmological constant. The qualitative analysis of the solutions for barotropic fluids with linear equations of state suggests that the behaviour is quite general.

  4. Spinning Particles in Scalar-Tensor Gravity with Torsion

    SciTech Connect

    Wang, C.-H.

    2008-10-10

    A new model of neutral spinning particles in scalar-tensor gravity with torsion is developed by using a Fermi coordinates associated with orthonormal frames attached to a timelike curve and Noether identities. We further analyze its equations of motion both in background Brans-Dicke torsion field and the constant pseudo-Riemannian curvature with a constant scalar field. It turns that the particle's spin vector is parallel transport along its wordline in the Brans-Dicke torsion field and de Sitter spacetime. However, the dynamics of the spinning particle cannot completely determined in anti-de Sitter spacetime and it requires a further investigation.

  5. Chern-Simons gravity in four dimensions

    NASA Astrophysics Data System (ADS)

    Morales, Ivan; Neves, Bruno; Oporto, Zui; Piguet, Olivier

    2017-02-01

    Five-dimensional Chern-Simons theory with (anti-)de Sitter SO(1,5) or SO(2,4) gauge invariance presents an alternative to general relativity with cosmological constant. We consider the zero modes of its Kaluza-Klein compactification to four dimensions. Solutions with vanishing torsion are obtained in the cases of a spherically symmetric 3-space and of a homogeneous and isotropic 3-space, which reproduce the Schwarzshild-de Sitter and Λ CDM cosmological solutions of general relativity. We also check that vanishing torsion is a stable feature of the solutions.

  6. A no-go theorem for monodromy inflation

    SciTech Connect

    Andriot, David

    2016-03-01

    We study the embedding of the monodromy inflation mechanism by E. Silverstein and A. Westphal (2008) in a concrete compactification setting. To that end, we look for an appropriate vacuum of type IIA supergravity, corresponding to the minimum of the inflaton potential. We prove a no-go theorem on the existence of such a vacuum, using ten-dimensional equations of motion. Anti-de Sitter and Minkowski vacua are ruled out; de Sitter vacua are not excluded, but have a lower bound on their cosmological constant which is too high for phenomenology.

  7. Massive spin-2 fields of geometric origin in curved spacetimes

    SciTech Connect

    Nair, V. P.; Randjbar-Daemi, S.; Rubakov, V.

    2009-11-15

    We study the consistency of a model which includes torsion as well as the metric as dynamical fields and has massive spin-2 particle in its spectrum. It is known that this model is tachyon free and ghost free in Minkowski background. We show that this property remains valid and no other pathologies emerge in de Sitter and anti-de Sitter backgrounds, with some of our results extending to arbitrary Einstein space backgrounds. This suggests that the model is consistent, at least at the classical level, unlike, e.g., the Fierz-Pauli theory.

  8. Insight into the microscopic structure of an AdS black hole from a thermodynamical phase transition.

    PubMed

    Wei, Shao-Wen; Liu, Yu-Xiao

    2015-09-11

    Comparing with an ordinary thermodynamic system, we investigate the possible microscopic structure of a charged anti-de Sitter black hole completely from the thermodynamic viewpoint. The number density of the black hole molecules is introduced to measure the microscopic degrees of freedom of the black hole. We found that the number density suffers a sudden change accompanied by a latent heat when the black hole system crosses the small-large black hole coexistence curve, while when the system passes the critical point, it encounters a second-order phase transition with a vanishing latent heat due to the continuous change of the number density. Moreover, the thermodynamic scalar curvature suggests that there is a weak attractive interaction between two black hole molecules. These phenomena might cast new insight into the underlying microscopic structure of a charged anti-de Sitter black hole.

  9. Warped-AdS3 black holes with scalar halo

    NASA Astrophysics Data System (ADS)

    Giribet, Gaston; Tsoukalas, Minas

    2015-09-01

    We construct a stretched (aka warped) anti-de Sitter black hole in three dimensions supported by a real scalar field configuration. The latter is regular everywhere outside and on the horizon. No-hair theorems in three dimensions demand the matter be coupled to the curvature in a nonminimal way; however, this coupling can still be of the Horndeski type, i.e. yielding second order field equations similar to those appearing in the context of Galileon theories. These warped-anti-de Sitter black holes exhibit interesting thermodynamical properties, such as finite Hawking temperature and entropy. We compute the black hole entropy in the gravity theory and speculate on the possibility of this to admit a microscopic description in terms of a dual (warped) conformal field theory. We also discuss the inner and outer black hole mechanics.

  10. Analytic solutions of the geodesic equation in higher dimensional static spherically symmetric spacetimes

    SciTech Connect

    Hackmann, Eva; Laemmerzahl, Claus; Kagramanova, Valeria; Kunz, Jutta

    2008-12-15

    The complete analytical solutions of the geodesic equation of massive test particles in higher dimensional Schwarzschild, Schwarzschild-(anti)de Sitter, Reissner-Nordstroem and Reissner-Nordstroem-(anti)de Sitter spacetimes are presented. Using the Jacobi inversion problem restricted to the theta divisor the explicit solution is given in terms of Kleinian sigma functions. The derived orbits depend on the structure of the roots of the characteristic polynomials which depend on the particle's energy and angular momentum, on the mass and the charge of the gravitational source, and the cosmological constant. We discuss the general structure of the orbits and show that due to the specific dimension-independent form of the angular momentum and the cosmological force a rich variety of orbits can emerge only in four and five dimensions. We present explicit analytical solutions for orbits up to 11 dimensions. A particular feature of Reissner-Nordstroem spacetimes is that bound and escape orbits traverse through different universes.

  11. Phase transition for black holes in dilatonic Einstein-Gauss-Bonnet theory of gravitation

    NASA Astrophysics Data System (ADS)

    Khimphun, Sunly; Lee, Bum-Hoon; Lee, Wonwoo

    2016-11-01

    We study the thermodynamic properties of a black hole and the Hawking-Page phase transition in the asymptotically anti-de Sitter spacetime in the dilatonic Einstein-Gauss-Bonnet theory of gravitation. We show how the higher-order curvature terms can influence both the thermodynamic properties and the phase transition. We evaluate both heat capacity and free energy difference to determine the local and global thermodynamic stabilities, respectively. We find that the phase transition occurs from the thermal anti-de Sitter to a small spherical black hole geometry and occurs to a hyperbolic black hole geometry in the (dilatonic) Einstein-Gauss-Bonnet theory of gravitation unlike those in Einstein's theory of gravitation.

  12. Hologram of a pure state black hole

    NASA Astrophysics Data System (ADS)

    Roy, Shubho R.; Sarkar, Debajyoti

    2015-12-01

    In this paper, we extend the Hamilton-Kabat-Lifschytz-Lowe (HKLL) holographic smearing function method to reconstruct (quasi)local anti-de Sitter bulk scalar observables in the background of a large anti-de Sitter black hole formed by null shell collapse (a "pure state" black hole), from the dual conformal field theory which is undergoing a sudden quench. In particular, we probe the near horizon and subhorizon bulk locality. First, we construct local bulk operators from the conformal field theory in the leading semiclassical limit, N →∞ . Then, we look at effects due to the finiteness of N , where we propose a suitable coarse-graining prescription involving early and late time cutoffs to define semiclassical bulk observables which are approximately local, their departure from locality being nonperturbatively small in N . Our results have important implications on the black hole information problem.

  13. Massive = 2 supergravity in three dimensions

    NASA Astrophysics Data System (ADS)

    Alkaç, Gökhan; Basanisi, Luca; Bergshoeff, Eric A.; Ozkan, Mehmet; Sezgin, Ergin

    2015-02-01

    There exists two distinct off-shell = 2 supergravities in three dimensions. They are also referred to as = (1, 1) and = (2, 0) supergravities, and they arise from the coupling of the Weyl multiplet to a compensating scalar or vector multiplet, respectively, followed by fixing of conformal symmetries. The = ( p, q) terminology refers to the underlying anti-de Sitter superalgebras OSp(2, p) ⊕ OSp(2, q) with R-symmetry group SO( p) × SO( q). We construct off-shell invariants of these theories up to fourth order in derivatives. As an application of these results, we determine the special combinations of the = (1, 1) invariants that admit anti-de Sitter vacuum solution about which there is a ghost-free massive spin-2 multiplet of propagating modes. We also show that the =(2,0) invariants do not allow such possibility.

  14. Topologically massive gravity and Ricci-Cotton flow

    NASA Astrophysics Data System (ADS)

    Lashkari, Nima; Maloney, Alexander

    2011-05-01

    We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.

  15. Rotating black string with nonlinear source

    SciTech Connect

    Hendi, S. H.

    2010-09-15

    In this paper, we derive rotating black string solutions in the presence of two kinds of nonlinear electromagnetic fields, so-called Born-Infeld and power Maxwell invariant. Investigation of the solutions show that for the Born-Infeld black string the singularity is timelike and the asymptotic behavior of the solutions is anti-de Sitter, but for power Maxwell invariant solutions, depending on the values of nonlinearity parameter, the singularity may be timelike as well as spacelike and the solutions are not asymptotically anti-de Sitter for all values of the nonlinearity parameter. Next, we calculate the conserved quantities of the solutions by using the counterterm method, and find that these quantities do not depend on the nonlinearity parameter. We also compute the entropy, temperature, the angular velocity, the electric charge, and the electric potential of the solutions, in which the conserved and thermodynamics quantities satisfy the first law of thermodynamics.

  16. The dissociation of the quarkonium with a holographic potential model

    NASA Astrophysics Data System (ADS)

    Wu, Yan; Zhang, Zi-qiang; Xiong, Zhong-long; Hou, De-fu

    2017-01-01

    The dissociation temperature of different quarkonium states has been examined with the anti de Sitter space/conformal field theory implied potential model. In order to determine the specific temperature, we explore the binding energy, average radius as well as the radial spectrum function with different bound states. It is shown that the internal energy between the constituent quarks is stronger than the free energy, and our melting temperatures are systematically lower than Lattice prediction.

  17. Chaotic dynamics of strings in charged black hole backgrounds

    NASA Astrophysics Data System (ADS)

    Basu, Pallab; Chaturvedi, Pankaj; Samantray, Prasant

    2017-03-01

    We study the motion of a string in the background of a Reissner-Nordstrom black hole, in both anti-de Sitter as well as asymptotically flat spacetimes. We describe the phase space of this dynamical system through the largest Lyapunov exponent, Poincaré sections and basins of attraction. We observe that string motion in these settings is particularly chaotic and comment on its characteristics.

  18. Equivalent equations of motion for gravity and entropy

    NASA Astrophysics Data System (ADS)

    Czech, Bartlomiej; Lamprou, Lampros; McCandlish, Samuel; Mosk, Benjamin; Sully, James

    2017-02-01

    We demonstrate an equivalence between the wave equation obeyed by the entanglement entropy of CFT subregions and the linearized bulk Einstein equation in Anti-de Sitter space. In doing so, we make use of the formalism of kinematic space [1] and fields on this space, introduced in [2]. We show that the gravitational dynamics are equivalent to a gauge invariant wave-equation on kinematic space and that this equation arises in natural correspondence to the conformal Casimir equation in the CFT.

  19. Chern-Simons action for inhomogeneous Virasoro group as extension of three dimensional flat gravity

    SciTech Connect

    Barnich, Glenn; Giribet, Gastón; Leston, Mauricio

    2015-07-15

    We initiate the study of a Chern-Simons action associated to the semi-direct sum of the Virasoro algebra with its coadjoint representation. This model extends the standard Chern-Simons formulation of three dimensional flat gravity and is similar to the higher-spin extension of three dimensional anti-de Sitter or flat gravity. The extension can also be constructed for the exotic but not for the cosmological constant deformation of flat gravity.

  20. AdS waves as exact solutions to quadratic gravity

    SciTech Connect

    Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram; Guerses, Metin

    2011-04-15

    We give an exact solution of the quadratic gravity in D dimensions. The solution is a plane-fronted wave metric with a cosmological constant. This metric solves not only the full quadratic gravity field equations but also the linearized ones which include the linearized equations of the recently found critical gravity. A subset of the solutions change the asymptotic structure of the anti-de Sitter space due to their logarithmic behavior.

  1. Extended Holography: Double-Trace Deformation and Brane-Induced Gravity Models

    NASA Astrophysics Data System (ADS)

    Barvinsky, A. O.

    2017-03-01

    We put forward a conjecture that for a special class of models - models of the double-trace deformation and brane-induced gravity types - the principle of holographic dualitiy can be extended beyond conformal invariance and anti-de Sitter (AdS) isometry. Such an extension is based on a special relation between functional determinants of the operators acting in the bulk and on the boundary.

  2. Black holes and wormholes in AdS branes

    SciTech Connect

    Molina, C.; Neves, J. C. S.

    2010-08-15

    In this work we have derived a class of geometries which describe black holes and wormholes in Randall-Sundrum-type brane models, focusing mainly on asymptotically anti-de Sitter backgrounds. We show that by continuously deforming the usual four-dimensional vacuum background, a specific family of solutions is obtained. Maximal extensions of the solutions are presented, and their causal structures are discussed.

  3. Graviton emission from a Gauss-Bonnet brane

    SciTech Connect

    Konya, Kenichiro

    2007-05-15

    We study the emission of gravitons by a homogeneous brane with the Gauss-Bonnet term into an anti-de Sitter five dimensional bulk spacetime. It is found that the graviton emission depends on the curvature scale and the Gauss-Bonnnet coupling and that the amount of emission generally decreases. Therefore nucleosynthesis constraints are easier to satisfy by including the Gauss-Bonnet term.

  4. Test fields cannot destroy extremal black holes

    NASA Astrophysics Data System (ADS)

    Natário, José; Queimada, Leonel; Vicente, Rodrigo

    2016-09-01

    We prove that (possibly charged) test fields satisfying the null energy condition at the event horizon cannot overspin/overcharge extremal Kerr-Newman or Kerr-Newman-anti de Sitter black holes, that is, the weak cosmic censorship conjecture cannot be violated in the test field approximation. The argument relies on black hole thermodynamics (without assuming cosmic censorship), and does not depend on the precise nature of the fields. We also discuss generalizations of this result to other extremal black holes.

  5. Time-evolution of the holographic entanglement entropy and metric perturbationst

    NASA Astrophysics Data System (ADS)

    Kim, Nakwoo; Lee, Jung Hun

    2016-08-01

    We study the holographic entanglement entropy under small deformations of anti-de Sitter (AdS) spacetime, including its time-dependence. Through perturbative analysis, the divergent terms are found not to be affected, and the change appears only in the finite terms. We also consider the entanglement thermodynamic first law, calculate the entanglement temperature, and confirm that it is inversely proportional to the size of the entangling region.

  6. The Cartan algorithm in five dimensions

    NASA Astrophysics Data System (ADS)

    McNutt, D. D.; Coley, A. A.; Forget, A.

    2017-03-01

    In this paper, we introduce an algorithm to determine the equivalence of five dimensional spacetimes, which generalizes the Karlhede algorithm for four dimensional general relativity. As an alternative to the Petrov type classification, we employ the alignment classification to algebraically classify the Weyl tensor. To illustrate the algorithm, we discuss three examples: the singly rotating Myers-Perry solution, the Kerr (Anti-) de Sitter solution, and the rotating black ring solution. We briefly discuss some applications of the Cartan algorithm in five dimensions.

  7. Evidence for an electrifying violation of cosmic censorship

    NASA Astrophysics Data System (ADS)

    Horowitz, Gary T.; Santos, Jorge E.; Way, Benson

    2016-10-01

    We present a plausible counterexample to cosmic censorship in four-dimensional Einstein-Maxwell theory with asymptotically anti-de Sitter boundary conditions. Smooth initial data evolves to a region of arbitrarily large curvature that is visible to distant observers. Our example is based on a holographic model of an electrically charged, localised defect which was previously studied at zero temperature. We partially extend those results to nonzero temperatures.

  8. Chaos in AdS2 Holography

    NASA Astrophysics Data System (ADS)

    Jensen, Kristan

    2016-09-01

    We revisit two-dimensional holography with the Sachdev-Ye-Kitaev models in mind. Our main result is to rewrite a generic theory of gravity near a two-dimensional anti-de Sitter spacetime throat as a novel hydrodynamics coupled to the correlation functions of a conformal quantum mechanics. This gives a prescription for the computation of n -point functions in the dual quantum mechanics. We thereby find that the dual is maximally chaotic.

  9. Quasinormal Modes for Schwarzschild-AdS Black Holes: Exponential Convergence to the Real Axis

    NASA Astrophysics Data System (ADS)

    Gannot, Oran

    2014-09-01

    We study quasinormal modes for massive scalar fields in Schwarzschild-anti-de Sitter black holes. When the mass-squared is above the Breitenlohner-Freedman bound, we show that for large angular momenta, ℓ, there exist quasinormal modes with imaginary parts of size exp(- ℓ/ C). We provide an asymptotic expansion for the real parts of the modes closest to the real axis and identify the vanishing of certain coefficients depending on the dimension.

  10. Global scaling symmetry, Noether charge, and universality of shear viscosity

    NASA Astrophysics Data System (ADS)

    Liu, Hai-Shan

    2016-05-01

    Recently, it was established in Einstein-Maxwell-Dilaton gravity that the Kovtun-Son-Starinets viscosity/entropy ratio associated with anti-de Sitter planar black holes can be viewed as the boundary dual to the generalized Smarr relation of the black holes in the bulk. In this paper, we establish this relation in Einstein gravity with general minimally coupled matter and also in theories with an additional nonminimally coupled scalar field. We consider two examples for explicit demonstrations.

  11. Exact four-dimensional dyonic black holes and Bertotti-Robinson spacetimes in string theory

    NASA Astrophysics Data System (ADS)

    Lowe, David A.; Strominger, Andrew

    1994-09-01

    Conformal field theories corresponding to two-dimensional electrically charged black holes and to two-dimensional anti-de Sitter space with a covariantly constant electric field are simply constructed as SL(2,openR)/openZ Wess-Zumino-Witten coset models. Four-dimensional spacetime solutions are obtained by tensoring these two-dimensional theories with SU(2)/Z(m) coset models. These describe a family of dyonic black holes and the Bertotti-Robinson universe.

  12. Minimal massive 3D gravity

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.

    2014-07-01

    We present an alternative to topologically massive gravity (TMG) with the same ‘minimal’ bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new ‘minimal massive gravity’ has both a positive energy graviton and positive central charges for the asymptotic AdS-boundary conformal algebra.

  13. New improved massive gravity

    NASA Astrophysics Data System (ADS)

    Dereli, T.; Yetişmişoğlu, C.

    2016-06-01

    We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first-order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space AdS 3) and constant torsion provide exact solutions.

  14. New improved massive gravity and three-dimensional spacetimes of constant curvature and constant torsion

    NASA Astrophysics Data System (ADS)

    Dereli, Tekin; Yetişmişoǧlu, Cem

    2016-09-01

    We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti-de Sitter space AdS3) and constant torsion provide exact solutions.

  15. Holographic vitrification

    NASA Astrophysics Data System (ADS)

    Anninos, Dionysios; Anous, Tarek; Denef, Frederik; Peeters, Lucas

    2015-04-01

    We establish the existence of stable and metastable stationary black hole bound states at finite temperature and chemical potentials in global and planar four-dimensional asymptotically anti-de Sitter space. We determine a number of features of their holographic duals and argue they represent structural glasses. We map out their thermodynamic landscape in the probe approximation, and show their relaxation dynamics exhibits logarithmic aging, with aging rates determined by the distribution of barriers.

  16. Super-W∞ asymptotic symmetry of higher-spin AdS3 supergravity

    NASA Astrophysics Data System (ADS)

    Henneaux, Marc; Gómez, Gustavo Lucena; Park, Jaesung; Rey, Soo-Jong

    2012-06-01

    We consider (2 + 1)-dimensional ( N, M)-extended higher-spin anti-de Sitter supergravity and study its asymptotic symmetries. The theory is described by the Chern-Simons action based on the real, infinite-dimensional higher-spin superalgebra {{sh}}{{{s}}^{{E}}}( {N|{2},{R}} ) oplus {{sh}}{{{s}}^{{E}}}( {M|{2},{R}} ) . We specify consistent boundary conditions on the higher-spin super-gauge connection corresponding to asymptotically anti-de Sitter spacetimes. We then determine the residual gauge transformations that preserve these asymptotic conditions and compute their Poisson bracket algebra. We find that the asymptotic symmetry is enhanced from the higher- spin superalgebra to some ( N, M)-extended super-W∞ nonlinear superalgebra. The latter has the same classical central charge as pure Einstein gravity. Special attention is paid to the (1 ,1) case. Truncation to the bosonic sector yields the previously found W∞ algebra, while truncation to the osp ( {N|{2},{R}} ) sector reproduces the N -extended superconformal algebra (in its nonlinear version for N > 2). We discuss string theory realization of these higher-spin anti-de Sitter supergravity theories as well as relations to previous treatments of super-W∞ in the literature.

  17. Regular phantom black holes.

    PubMed

    Bronnikov, K A; Fabris, J C

    2006-06-30

    We study self-gravitating, static, spherically symmetric phantom scalar fields with arbitrary potentials (favored by cosmological observations) and single out 16 classes of possible regular configurations with flat, de Sitter, and anti-de Sitter asymptotics. Among them are traversable wormholes, bouncing Kantowski-Sachs (KS) cosmologies, and asymptotically flat black holes (BHs). A regular BH has a Schwarzschild-like causal structure, but the singularity is replaced by a de Sitter infinity, giving a hypothetic BH explorer a chance to survive. It also looks possible that our Universe has originated in a phantom-dominated collapse in another universe, with KS expansion and isotropization after crossing the horizon. Explicit examples of regular solutions are built and discussed. Possible generalizations include k-essence type scalar fields (with a potential) and scalar-tensor gravity.

  18. TOPICAL REVIEW: Asymptotic directional structure of radiative fields in spacetimes with a cosmological constant

    NASA Astrophysics Data System (ADS)

    Krtous, Pavel; Podolský, Jirí

    2004-12-01

    We analyse the directional properties of general gravitational, electromagnetic and spin-s fields near conformal infinity \\scri . The fields are evaluated in normalized tetrads which are parallelly propagated along null geodesics which approach a point P of \\scri . The standard peeling-off property is recovered and its meaning is discussed and refined. When the (local) character of the conformal infinity is null, such as in asymptotically flat spacetimes, the dominant term which is identified with radiation is unique. However, for spacetimes with a non-vanishing cosmological constant the conformal infinity is spacelike (for Λ > 0) or timelike (for Λ < 0), and the radiative component of each field depends substantially on the null direction along which P is approached. The directional dependence of asymptotic fields near such de Sitter-like or anti-de Sitter-like \\scri is explicitly found and described. We demonstrate that the corresponding directional structure of radiation has a universal character that is determined by the algebraic (Petrov) type of the field. In particular, when Λ > 0 the radiation vanishes only along directions which are opposite to principal null directions. For Λ < 0 the directional dependence is more complicated because it is necessary to distinguish outgoing and ingoing radiation. Near such anti-de Sitter-like conformal infinity the corresponding directional structures differ, depending not only on the number and degeneracy of the principal null directions at P but also on their specific orientation with respect to \\scri . The directional structure of radiation near (anti-)de Sitter-like infinities supplements the standard peeling-off property of spin-s fields. This characterization offers a better understanding of the asymptotic behaviour of the fields near conformal infinity under the presence of a cosmological constant.

  19. Spectator field dynamics in de Sitter and curvaton initial conditions

    SciTech Connect

    Enqvist, Kari; Lerner, Rose N.; Taanila, Olli; Tranberg, Anders E-mail: rose.lerner@helsinki.fi E-mail: antranbe@nbi.dk

    2012-10-01

    We investigate the stochastic behaviour of long wavelength modes of light spectator scalar fields during inflation. When starting from a classical field value, the probability distribution for the spectator both spreads out and moves towards an equilibrium distribution. We study the timescales for a mixed quadratic and quartic potential. The timescale of equilibration depends on the parameters of the model, and can be surprisingly large, more than thousands of e-folds for the majority of light spectators. These results imply that the initial conditions for spectator fields are not automatically erased during inflation. These general results can be used to determine the probability of the value of the zero-mode inside a Universe-sized patch, which is relevant for observations. As an example, we apply the results to the curvaton model to calculate the probability distribution of the curvature perturbation and discuss 'typical' Universes.

  20. Tunneling constraints on effective theories of stable de Sitter space

    SciTech Connect

    Banks, Tom; Fortin, Jean-Francois

    2009-10-01

    We argue that effective field theories compatible with the idea of cosmological supersymmetry breaking (CSB) can have no supersymmetric vacuum states in the M{sub P}{yields}{infinity} limit. We introduce a revised version of the pyramid scheme, which satisfies this criterion. Combining the criteria for CSB with results of Nelson and Seiberg, any such Lagrangian is nongeneric, but we argue that this is plausible in the context of CSB, where R-violating terms in the Lagrangian come from interactions with the horizon, rather than integrating out short distance degrees of freedom. We also point out a Landau pole in the hidden sector gauge group of the pyramid scheme, and propose a mechanism for avoiding it.

  1. Early universe thermostatistics in curved momentum spaces

    NASA Astrophysics Data System (ADS)

    Gorji, M. A.; Hosseinzadeh, V.; Nozari, K.; Vakili, B.

    2016-03-01

    The theories known as doubly special relativity are introduced in order to take into account an observer-independent length scale and the speed of light in the framework of special relativity. These theories can be generally formulated on the de Sitter and also recently proposed anti-de Sitter momentum spaces. In the context of these theories, we study the statistical mechanics, and to do this, we consider the natural measure on the corresponding extended phase space. The invariant measure on the space of distinct microstates is obtained by restriction of the natural measure of the extended phase space to the physical phase space through the disintegration theorem. Having the invariant measure, one can study the statistical mechanics in an arbitrary ensemble for any doubly special relativity theory. We use the constructed setup to study the statistical properties of four doubly special relativity models. Applying the results to the case of early universe thermodynamics, we show that one of these models that is defined by the cosmological coordinatization of anti-de Sitter momentum space implies a finite total number of microstates. Therefore, without attribution to any ensemble density, and quite generally, we obtain entropy and internal energy bounds for the early radiation dominated universe. We find that while these results cannot be supported by the standard Friedmann equations, they indeed are in complete agreement with the nonsingular effective Friedmann equations that arise in the context of loop quantum cosmology.

  2. Massive vector field perturbations in the Schwarzschild background: Stability and quasinormal spectrum

    SciTech Connect

    Konoplya, R. A.

    2006-01-15

    We consider the perturbations of the massive vector field around Schwarzschild, Schwarzschild-de Sitter, and Schwarzschild-anti-de Sitter black holes. Equations for a spherically symmetric massive vector perturbation can be reduced to a single wavelike equation. We have proved the stability against these perturbations and investigated the quasinormal spectrum. The quasinormal behavior for Schwarzschild black hole is quite unexpected: the fundamental mode and higher overtones show totally different dependence on the mass of the field m: as m is increasing, the damping rate of the fundamental mode is decreasing, what results in appearing of the infinitely long living modes, while, on the contrary, damping rate of all higher overtones are increasing, and their real oscillation frequencies gradually go to tiny values. Thereby, for all higher overtones, almost nonoscillatory, damping modes can exist. In the limit of asymptotically high damping, Re{omega} goes to ln3/(8{pi}M), while imaginary part shows equidistant behavior with spacing Im{omega}{sub n+1}-Im{omega}{sub n}=1/4M. In addition, we have found quasinormal spectrum of massive vector field for Schwarzschild-anti-de Sitter black hole.

  3. Integrability in conformally coupled gravity: Taub-NUT spacetimes and rotating black holes

    NASA Astrophysics Data System (ADS)

    Bardoux, Yannis; Caldarelli, Marco M.; Charmousis, Christos

    2014-05-01

    We consider four dimensional stationary and axially symmetric spacetimes for conformally coupled scalar-tensor theories. We show that, in analogy to the Lewis-Papapetrou problem in General Relativity (GR), the theory at hand can be recast in an analogous integrable form. We give the relevant rod formalism, introduced by Weyl for vacuum GR, explicitly giving the rod structure of the black hole of Bocharova et al. and Bekenstein (BBMB), in complete analogy to the Schwarzschild solution. The additional scalar field is shown to play the role of an extra Weyl potential. We then employ the Ernst method as a concrete solution generating example to obtain the Taub-NUT version of the BBMB hairy black hole. The solution is easily extended to include a cosmological constant. We show that the anti-de Sitter hyperbolic version of this solution is free of closed timelike curves that plague usual Taub-NUT metrics, and thus consists of a rotating, asymptotically locally anti-de Sitter black hole. This stationary solution has no curvature singularities whatsoever in the conformal frame, and the NUT charge is shown here to regularize the central curvature singularity of the corresponding static black hole. Given our findings we discuss the anti-de Sitter hyperbolic version of Taub-NUT in four dimensions, and show that the curvature singularity of the NUT-less solution is now replaced by a neighbouring chronological singularity screened by horizons. We argue that the properties of this rotating black hole are very similar to those of the rotating BTZ black hole in three dimensions.

  4. Wormholes and black universes communicated with extra dimensions

    NASA Astrophysics Data System (ADS)

    Bronnikov, K. A.; Korolyov, P. A.; Makhmudov, A.; Skvortsova, M. V.

    2017-01-01

    In 6D general relativity with a phantom scalar field as a source of gravity, we present solutions that implement a transition from an effective 4D geometry times small extra dimensions to an effectively 6D space-time where the physical laws are different from ours. We consider manifolds with the structure 𝕄0×𝕄1×𝕄2, where 𝕄0 is 2D Lorentzian space-time while each of 𝕄1,2 can be a 2-sphere or a 2-torus. Some solutions describe wormholes with spherical symmetry in our space-time and toroidal extra dimensions. Others are of black universe type: at one end there is a 6D asymptotically anti-de Sitter black hole while beyond the horizon the geometry tends to a 4D de Sitter cosmology times a small 2D spherical extra space.

  5. Inner mechanics of three-dimensional black holes.

    PubMed

    Detournay, Stéphane

    2012-07-20

    We investigate properties of the inner horizons of certain black holes in higher-derivative three-dimensional gravity theories. We focus on Bañados-Teitelboim-Zanelli and spacelike warped anti-de Sitter black holes, as well as on asymptotically warped de Sitter solutions exhibiting both a cosmological and a black hole horizon. We verify that a first law is satisfied at the inner horizon, in agreement with the proposal of Castro and Rodriguez [arXiv:1204.1284]. We then show that, in topologically massive gravity, the product of the areas of the inner and outer horizons fails to be independent on the mass, and we trace this to the diffeomorphism anomaly of the theory.

  6. Photon gas thermodynamics in dS and AdS momentum spaces

    NASA Astrophysics Data System (ADS)

    Gorji, M. A.; Hosseinzadeh, V.; Nozari, K.; Vakili, B.

    2016-07-01

    In this paper, we study thermostatistical properties of a photon gas in the framework of two deformed special relativity models defined by the cosmological coordinatizations of the de Sitter (dS) and anti-de Sitter (AdS) momentum spaces. The dS model is a doubly special relativity theory in which an ultraviolet length scale is invariant under the deformed Lorentz transformations. For the case of the AdS model, however, the Lorentz symmetry breaks at the high energy regime. We show that the existence of a maximal momentum in dS momentum space leads to maximal pressure and temperature at the thermodynamical level, while maximal internal energy and entropy arise for the case of the AdS momentum space due to the existence of a maximal kinematical energy. These results show that the thermodynamical duality of these models is very similar to their well-known kinematical duality.

  7. Charged compact boson stars and shells in the presence of a cosmological constant

    NASA Astrophysics Data System (ADS)

    Kumar, Sanjeev; Kulshreshtha, Usha; Kulshreshtha, Daya Shankar

    2016-12-01

    In this work, we study the boson stars and boson shells in a theory involving massive complex scalar fields coupled to the U(1) gauge field and gravity in a conical potential in the presence of a cosmological constant Λ which we treat as a free parameter taking positive and negative values and thereby allowing us to study the theory in the de Sitter and anti-de Sitter spaces respectively. Boson stars are found to come in two types, having either ball-like or shell-like charge density. We have studied the properties of these solutions and have also determined their domains of existence for some specific values of the parameters of the theory. Similar solutions have also been obtained by Kleihaus et al. in a theory involving massless complex scalar fields coupled to the U(1) gauge field and gravity in a conical potential in the absence of a cosmological constant Λ .

  8. Remarks on scale separation in flux vacua

    NASA Astrophysics Data System (ADS)

    Gautason, F. F.; Schillo, M.; Van Riet, T.; Williams, M.

    2016-03-01

    We argue that the Maldacena-Nuñez no-go theorem excluding Minkowski and de Sitter vacua in flux compactifications can be extended to anti-de Sitter (AdS) vacua for which the Kaluza-Klein scale is parametrically smaller than the AdS length scale. In the absence of negative tension sources, scale-separated AdS vacua are ruled out in 11-dimensional supergravity; in 10-dimensional supergravity, we show that such vacua can only arise in conjunction with large dilaton gradients. As a practical application of this observation we demonstrate that the mechanism to resolve O6 singularities in massive type IIA at the classical level is likely not to occur in AdS compactifications with scale separation. We furthermore remark that a compactification to four observable dimensions implies a large cosmological hierarchy.

  9. Stability of thin-shell wormholes from a regular ABG black hole

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Mumtaz, Saadia

    2017-01-01

    In this paper, we construct thin-shell wormholes from a regular Ayon-Beato-Garcia black hole by employing cut and paste formalism and examine their stability. We analyze attractive and repulsive characteristics of the respective thin-shell wormholes. A general equation of state is assumed as a linear perturbation to explore stability of these constructed wormholes with and without cosmological constant. We consider linear, logarithmic and Chaplygin gas models for exotic matter and evaluate stability regions for different values of charge. It is found that the generalized Chaplygin gas model provides maximum stable regions in the de Sitter background while the modified generalized Chaplygin gas and logarithmic gas yield maximum stable regions in the anti-de Sitter spacetime.

  10. Conceptual Aspects of Gauge/Gravity Duality

    NASA Astrophysics Data System (ADS)

    De Haro, Sebastian; Mayerson, Daniel R.; Butterfield, Jeremy N.

    2016-11-01

    We give an introductory review of gauge/gravity duality, and associated ideas of holography, emphasising the conceptual aspects. The opening sections gather the ingredients, viz. anti-de Sitter spacetime, conformal field theory and string theory, that we need for presenting, in Sect. 5, the central and original example: Maldacena's AdS/CFT correspondence. Sections 6 and 7 develop the ideas of this example, also in applications to condensed matter systems, QCD, and hydrodynamics. Sections 8 and 9 discuss the possible extensions of holographic ideas to de Sitter spacetime and to black holes. Section 10 discusses the bearing of gauge/gravity duality on two philosophical topics: the equivalence of physical theories, and the idea that spacetime, or some features of it, are emergent.

  11. Gauge theories on A(dS) space and Killing vectors

    SciTech Connect

    Banerjee, Rabin Majhi, Bibhas Ranjan

    2008-03-15

    We provide a general technique for collectively analysing a manifestly covariant formulation of non-abelian gauge theories on both anti-de Sitter as well as de Sitter spaces. This is done by stereographically projecting the corresponding theories, defined on a flat Minkowski space, onto the surface of the A(dS) hyperboloid. The gauge and matter fields in the two descriptions are mapped by conformal Killing vectors and conformal Killing spinors, respectively. A bilinear map connecting the spinors with the vector is established. Different forms of gauge fixing conditions and their equivalence are discussed. The U(1) axial anomaly as well as the non-abelian covariant and consistent chiral anomalies on A(dS) space are obtained. Electric-magnetic duality is demonstrated. The zero curvature limit is shown to yield consistent findings.

  12. Gravitationally collapsing shells in (2+1) dimensions

    SciTech Connect

    Mann, Robert B.; Oh, John J.

    2006-12-15

    We study gravitationally collapsing models of pressureless dust, fluids with pressure, and the generalized Chaplygin gas (GCG) shell in (2+1)-dimensional spacetimes. Various collapse scenarios are investigated under a variety of the background configurations such as anti-de Sitter (AdS) black hole, de Sitter (dS) space, flat and AdS space with a conical deficit. As with the case of a disk of dust, we find that the collapse of a dust shell coincides with the Oppenheimer-Snyder type collapse to a black hole provided the initial density is sufficiently large. We also find - for all types of shell - that collapse to a naked singularity is possible under a broad variety of initial conditions. For shells with pressure this singularity can occur for a finite radius of the shell. We also find that GCG shells exhibit diverse collapse scenarios, which can be easily demonstrated by an effective potential analysis.

  13. Generalized Skyrmions and hairy black holes in asymptotically AdS4 spacetime

    NASA Astrophysics Data System (ADS)

    Perapechka, I.; Shnir, Ya.

    2017-01-01

    We investigate the properties of spherically symmetric black-hole solutions in the generalized Einstein-Skyrme model theory in four-dimensional asymptotically anti-de Sitter spacetime. The dependences of the Skyrmion fields on the cosmological constant and on the strength of the effective gravitational coupling are examined. We show that the increase of the absolute value of the cosmological constant qualitatively yields the same effect as increasing the effective gravitational coupling. We confirm that, similar to the model in asymptotically flat spacetime, a necessary condition for the existence of black holes with Skyrmionic hair is the inclusion of the Skyrme term.

  14. Superfluid Black Holes

    NASA Astrophysics Data System (ADS)

    Hennigar, Robie A.; Mann, Robert B.; Tjoa, Erickson

    2017-01-01

    We present what we believe is the first example of a "λ -line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid 4He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  15. c-functions in the Born-Infeld extended new massive gravity

    SciTech Connect

    Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram

    2010-07-15

    We derive and study the equations of motion of the Born-Infeld extension of new massive gravity for globally and asymptotically (anti-)de Sitter spaces, and show that the assumptions of the null-energy condition and holography (that bounds the c-function) lead to two simple c-functions, one of which is equivalent to the c-function of Einstein's gravity. We also show that, at the fixed point, the c-function gives the central charge of the Virasoro algebra and the coefficient of the Weyl anomaly up to a constant.

  16. AdS Black Disk Model for Small-x Deep Inelastic Scattering

    NASA Astrophysics Data System (ADS)

    Cornalba, Lorenzo; Costa, Miguel S.; Penedones, João

    2010-08-01

    Using the approximate conformal invariance of QCD at high energies we consider a simple anti-de Sitter black disk model to describe saturation in deep inelastic scattering. Deep inside saturation the structure functions have the same power law scaling, FT˜FL˜x-ω, where ω is related to the expansion rate of the black disk with energy. Furthermore, the ratio FL/FT is given by the universal value (1+ω)/(3+ω), independently of the target. For γ*-γ* scattering at high energies we obtain explicit expressions and ratios for the total cross sections of transverse and longitudinal photons in terms of the single parameter ω.

  17. Holographic heavy ion collisions with baryon charge

    NASA Astrophysics Data System (ADS)

    Casalderrey-Solana, Jorge; Mateos, David; van der Schee, Wilke; Triana, Miquel

    2016-09-01

    We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15%. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.

  18. Entropy Inequality Violations from Ultraspinning Black Holes.

    PubMed

    Hennigar, Robie A; Mann, Robert B; Kubizňák, David

    2015-07-17

    We construct a new class of rotating anti-de Sitter (AdS) black hole solutions with noncompact event horizons of finite area in any dimension and study their thermodynamics. In four dimensions these black holes are solutions to gauged supergravity. We find that their entropy exceeds the maximum implied from the conjectured reverse isoperimetric inequality, which states that for a given thermodynamic volume, the black hole entropy is maximized for Schwarzschild-AdS space. We use this result to suggest more stringent conditions under which this conjecture may hold.

  19. Static Einstein-Maxwell Black Holes with No Spatial Isometries in AdS Space.

    PubMed

    Herdeiro, Carlos A R; Radu, Eugen

    2016-11-25

    We explicitly construct static black hole solutions to the fully nonlinear, D=4, Einstein-Maxwell-anti-de Sitter (AdS) equations that have no continuous spatial symmetries. These black holes have a smooth, topologically spherical horizon (section), but without isometries, and approach, asymptotically, global AdS spacetime. They are interpreted as bound states of a horizon with the Einstein-Maxwell-AdS solitons recently discovered, for appropriate boundary data. In sharp contrast to the uniqueness results for a Minkowski electrovacuum, the existence of these black holes shows that single, equilibrium, black hole solutions in an AdS electrovacuum admit an arbitrary multipole structure.

  20. Superfluid Black Holes.

    PubMed

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  1. On the Center of Mass of Asymptotically Hyperbolic Initial Data Sets

    NASA Astrophysics Data System (ADS)

    Cederbaum, Carla; Cortier, Julien; Sakovich, Anna

    2016-06-01

    We define the (total) center of mass for suitably asymptotically hyperbolic time-slices of asymptotically anti-de Sitter spacetimes in general relativity. We do so in analogy to the picture that has been consolidated for the (total) center of mass of suitably asymptotically Euclidean time-slices of asymptotically Minkowskian spacetimes (isolated systems). In particular, we unite -- an altered version of -- the approach based on Hamiltonian charges with an approach based on CMC-foliations near infinity. The newly defined center of mass transforms appropriately under changes of the asymptotic coordinates and evolves in the direction of an appropriately defined linear momentum under the Einstein evolution equations.

  2. Rainbow vacua of colored higher-spin (A)dS3 gravity

    NASA Astrophysics Data System (ADS)

    Gwak, Seungho; Joung, Euihun; Mkrtchyan, Karapet; Rey, Soo-Jong

    2016-05-01

    We study the color-decoration of higher-spin (anti)-de Sitter gravity in three dimensions. We show that the rainbow vacua, which we found recently for the colored gravity theory, also pertain in the colored higher-spin theory. The color singlet spin-two plays the role of first fundamental form (metric). The difference is that when spontaneous breaking of color symmetry takes place, the Goldstone modes of massless spin-two combine with all other spins and become the maximal-depth partially massless fields of the highest spin in the theory, forming a Regge trajectory.

  3. Intersecting D 3 -D3 ' -brane system at finite temperature

    NASA Astrophysics Data System (ADS)

    Cottrell, William; Hanson, James; Hashimoto, Akikazu; Loveridge, Andrew; Pettengill, Duncan

    2017-02-01

    We analyze the dynamics of the intersecting D 3 -D3 ' -brane system overlapping in 1 +1 dimensions, in a holographic treatment where N D3 branes are manifested as anti-de Sitter Schwartzschild geometry, and the D3 ' brane is treated as a probe. We extract the thermodynamic equation of state from the set of embedding solutions, and analyze the stability at the perturbative and the nonperturbative level. We review a systematic procedure to resolve local instabilities and multivaluedness in the equations of state based on classic ideas of convexity in the microcanonical ensemble. We then identify a runaway behavior which was not noticed previously for this system.

  4. Late time behavior of false vacuum decay: possible implications for cosmology and metastable inflating states.

    PubMed

    Krauss, Lawrence M; Dent, James

    2008-05-02

    We describe here how the late time behavior of the quantum mechanical decay of unstable states, which is predicted to deviate from an exponential form, may have important cosmological implications. It may increase the likelihood of eternal inflation and may enhance the likelihood of observing a small vacuum energy at late times versus possible late time decay into a large negative energy (anti-de Sitter space) vacuum state. Open questions include the following: How can internal observations made impact upon the wave function of the Universe and hence upon its decay characteristics?

  5. Novel Cauchy-horizon instability

    SciTech Connect

    Maeda, Hideki; Torii, Takashi; Harada, Tomohiro

    2005-03-15

    The evolution of weak discontinuity is investigated on horizons in the n-dimensional static solutions in the Einstein-Maxwell-scalar-{lambda} system, including the Reissner-Nordstroem-(anti) de Sitter black hole. The analysis is essentially local and nonlinear. We find that the Cauchy horizon is unstable, whereas both the black hole event horizon and the cosmological event horizon are stable. This new instability, the so-called kink instability, of the Cauchy horizon is completely different from the well-known 'infinite-blueshift' instability. The kink instability makes the analytic continuation beyond the Cauchy horizon unstable.

  6. Exact solutions in R2 SUGRA

    NASA Astrophysics Data System (ADS)

    Cisterna, Adolfo; Hassaïne, Mokhtar; Oliva, Julio

    2015-11-01

    This paper is devoted to showing that the bosonic sector of R2 supergravity in four dimensions, constructed with the F term, admits a variety of exact and analytic solutions which include pp and anti-de Sitter (AdS) waves, asymptotically flat and AdS black holes and wormholes, as well as product spacetimes. The existence of static black holes and wormholes implies that a combination involving the Ricci scalar plus the norm of the field strength of the auxiliary two-form Bμ ν must be a constant. We focus on this sector of the theory, which has two subsectors depending on whether such a combination vanishes.

  7. Summary of session B3 at GR20/Amaldi10

    NASA Astrophysics Data System (ADS)

    Garfinkle, David

    2014-05-01

    A wide variety of results was presented in session B3, the "non-astrophysical" numerical relativity parallel session. some results included improved numerical methods for such things as asymptotically flat spacetimes, generation of initial data, and characterization of binary black hole systems. Others included the propagation of various types of matter fields in the presence of black holes, naked singularities, and wormholes. There were also several simulations of spacetimes asymptotic to anti-de Sitter space. These simulations are of interest both for general relativity and (through the AdS/CFT correspondence) for the behavior of quantum field theories.

  8. Universality of the diffusion wake in the gauge-string duality

    SciTech Connect

    Gubser, Steven S.; Yarom, Amos

    2008-03-15

    As a particle moves through a fluid, it may generate a laminar wake behind it. In the gauge-string duality, we show that such a diffusion wake is created by a heavy quark moving through a thermal plasma and that it has a universal strength when compared to the total drag force exerted on the quark by the plasma. The universality extends over all asymptotically anti-de Sitter supergravity constructions with arbitrary scalar matter. We discuss how these results relate to the linearized hydrodynamic approximation and how they bear on our understanding of di-hadron correlators in heavy ion collisions.

  9. Gravity Dual to a Quantum Critical Point with Spontaneous Symmetry Breaking

    SciTech Connect

    Gubser, Steven S.; Rocha, Fabio D.

    2009-02-13

    We consider zero-temperature solutions to the Abelian Higgs model coupled to gravity with a negative cosmological constant. With appropriate choices of parameters, the geometry contains two copies of anti-de Sitter space, one describing conformal invariance in the ultraviolet, and one in the infrared. The effective speed of signal propagation is smaller in the infrared. Green's functions and associated transport coefficients can have unusual power-law scaling in the infrared. We provide an example in which the real part of the conductivity scales approximately as {omega}{sup 3.5} for small {omega}.

  10. Black Plane Solutions and Localized Gravitational Energy

    PubMed Central

    Roberts, Jennifer

    2015-01-01

    We explore the issue of gravitational energy localization for static plane-symmetric solutions of the Einstein-Maxwell equations in 3+1 dimensions with asymptotic anti-de Sitter behavior. We apply three different energy-momentum complexes, the Einstein, Landau-Lifshitz, and Møller prescriptions, to the metric representing this category of solutions and determine the energy distribution for each. We find that the three prescriptions offer identical energy distributions, suggesting their utility for this type of model. PMID:27347499

  11. Classification of maximally supersymmetric backgrounds in supergravity theories

    NASA Astrophysics Data System (ADS)

    Louis, Jan; Lüst, Severin

    2017-02-01

    We study maximally supersymmetric solutions of all gauged or deformed supergravity theories in D ≥ 3 space-time dimensions. For vanishing background fluxes the space-time background has to be either Minkowski or anti-de Sitter. We derive a simple criterion for the existence of solutions with non-trivial fluxes and determine all supergravities that satisfy it. We show that their solutions coincide with those of the corresponding ungauged theories and conclude that the known list of maximally supersymmetric solutions is exhaustive.

  12. Holographic Complexity Equals Bulk Action?

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-05-01

    We conjecture that the quantum complexity of a holographic state is dual to the action of a certain spacetime region that we call a Wheeler-DeWitt patch. We illustrate and test the conjecture in the context of neutral, charged, and rotating black holes in anti-de Sitter spacetime, as well as black holes perturbed with static shells and with shock waves. This conjecture evolved from a previous conjecture that complexity is dual to spatial volume, but appears to be a major improvement over the original. In light of our results, we discuss the hypothesis that black holes are the fastest computers in nature.

  13. AdS Chern-Simons gravity induces conformal gravity

    NASA Astrophysics Data System (ADS)

    Aros, Rodrigo; Díaz, Danilo E.

    2014-04-01

    The leitmotif of this paper is the question of whether four- and higher even-dimensional conformal gravities do have a Chern-Simons pedigree. We show that Weyl gravity can be obtained as the dimensional reduction of a five-dimensional Chern-Simons action for a suitable (gauge-fixed, tractorlike) five-dimensional anti-de Sitter connection. The gauge-fixing and dimensional reduction program readily admits a generalization to higher dimensions for the case of certain conformal gravities obtained by contractions of the Weyl tensor.

  14. Euler-Lagrange equations for effective actions in QCD and gravity at high energies

    NASA Astrophysics Data System (ADS)

    Lipatov, L. N.

    2017-03-01

    Gluons in QCD and gravitons in quantum gravity lie on the Regge trajectories, which allows to formulate the high-energy scattering in these models in the framework of the reggeon field theory. In particular, the BFKL Pomeron is a composite state of reggeized gluons. In N = 4 SUSY the Pomeron is dual to the reggeized graviton living in the 10-dimensional anti-de-Sitter space. The effective actions for reggeized gluon and graviton interactions are formulated locally in the particle rapidities. The corresponding Euler-Lagrange equations are derived and their simple solutions are constructed.

  15. Baryon-number-induced Chern-Simons couplings of vector and axial-vector mesons in holographic QCD.

    PubMed

    Domokos, Sophia K; Harvey, Jeffrey A

    2007-10-05

    We show that holographic models of QCD predict the presence of a Chern-Simons coupling between vector and axial-vector mesons at finite baryon density. In the Anti de Sitter/Conformal Field Theory dictionary, the coefficient of this coupling is proportional to the baryon number density and is fixed uniquely in the five-dimensional holographic dual by anomalies in the flavor currents. For the lightest mesons, the coupling mixes transverse rho and a1 polarization states. At sufficiently large baryon number densities, it produces an instability, which causes the rho and a1 mesons to condense in a state breaking both rotational and translational invariance.

  16. Construction of regular black holes in general relativity

    NASA Astrophysics Data System (ADS)

    Fan, Zhong-Ying; Wang, Xiaobao

    2016-12-01

    We present a general procedure for constructing exact black hole solutions with electric or magnetic charges in general relativity coupled to a nonlinear electrodynamics. We obtain a variety of two-parameter family spherically symmetric black hole solutions. In particular, the singularity at the center of the space-time can be canceled in the parameter space and the black hole solutions become regular everywhere in space-time. We study the global properties of the solutions and derive the first law of thermodynamics. We also generalize the procedure to include a cosmological constant and construct regular black hole solutions that are asymptotic to anti-de Sitter space-time.

  17. Black hole collapse and democratic models

    NASA Astrophysics Data System (ADS)

    Jansen, Aron; Magán, Javier M.

    2016-11-01

    We study the evolution of black hole entropy and temperature in collapse scenarios in asymptotically anti-de Sitter spacetime, finding three generic lessons. First, entropy evolution is extensive. Second, at large times, entropy and temperature ring with twice the frequency of the lowest quasinormal mode. Third, the entropy oscillations saturate black hole area theorems in general relativity. The first two features are characteristic of entanglement dynamics in "democratic" models. Solely based on general relativity and the Bekenstein-Hawking entropy formula, our results point to democratic models as microscopic theories of black holes. The third feature can be taken as a prediction for microscopic models of black hole physics.

  18. Divergences and boundary modes in $$ \\mathcal{N}=8 $$ supergravity

    DOE PAGES

    Larsen, Finn; Lisbao, Pedro

    2016-01-07

    We reconsider the one loop divergence ofmore » $$ \\mathcal{N}=8 $$ supergravity in four dimensions. We compute the finite effective potential of $$ \\mathcal{N}=8 $$ anti-deSitter supergravity and interpret it as logarithmic running of the cosmological constant. We show that quantum inequivalence between fields that are classically dual is due to boundary modes in AdS4. In conclusion, the boundary modes are important in global AdS4 but not in thermal AdS4 since these geometries have different Euler characteristic.« less

  19. Gravity dual to a quantum critical point with spontaneous symmetry breaking.

    PubMed

    Gubser, Steven S; Rocha, Fábio D

    2009-02-13

    We consider zero-temperature solutions to the Abelian Higgs model coupled to gravity with a negative cosmological constant. With appropriate choices of parameters, the geometry contains two copies of anti-de Sitter space, one describing conformal invariance in the ultraviolet, and one in the infrared. The effective speed of signal propagation is smaller in the infrared. Green's functions and associated transport coefficients can have unusual power-law scaling in the infrared. We provide an example in which the real part of the conductivity scales approximately as omega;{3.5} for small omega.

  20. Representations of centrally extended Lie superalgebra psl(2|2)

    SciTech Connect

    Matsumoto, Takuya; Molev, Alexander

    2014-09-15

    The symmetries provided by representations of the centrally extended Lie superalgebra psl(2|2) are known to play an important role in the spin chain models originated in the planar anti-de Sitter/conformal field theory correspondence and one-dimensional Hubbard model. We give a complete description of finite-dimensional irreducible representations of this superalgebra thus extending the work of Beisert which deals with a generic family of representations. Our description includes a new class of modules with degenerate eigenvalues of the central elements. Moreover, we construct explicit bases in all irreducible representations by applying the techniques of Mickelsson–Zhelobenko algebras.

  1. Quantum stress tensor for a massive vector field in the space-time of a cylindrical black hole

    SciTech Connect

    Fernandez Piedra, Owen Pavel; Matyjasek, Jerzy

    2010-09-15

    The components of the renormalized quantum energy-momentum tensor for a massive vector field coupled to the gravitational field configuration of static 3+1 dimensional black strings in anti-de Sitter space are analytically evaluated using the Schwinger-DeWitt approximation. The general results are employed to investigate the pointwise energy conditions for the quantized matter field, and it is shown that they are violated at some regions of the space-time, in particular the horizon of the black hole.

  2. Affine generalization of the Komar complex of general relativity

    NASA Astrophysics Data System (ADS)

    Mielke, Eckehard W.

    2001-02-01

    On the basis of the ``on shell'' Noether identities of the metric-affine gauge approach of gravity, an affine superpotential is derived which comprises the energy- and angular-momentum content of exact solutions. In the special case of general relativity (GR) or its teleparallel equivalent, the Komar or Freud complex, respectively, are recovered. Applying this to the spontaneously broken anti-de Sitter gauge model of McDowell and Mansouri with an induced Euler term automatically yields the correct mass and spin of the Kerr-AdS solution of GR with a (induced) cosmological constant without the factor two discrepancy of the Komar formula.

  3. In-Out Formalism for One-Loop Effective Actions in QED and Gravity

    NASA Astrophysics Data System (ADS)

    Kim, S. P.

    2017-03-01

    The in-out formalism is a systematic and powerful method for finding the effective actions in an electromagnetic field and a curved spacetime provided that the field equation has explicitly known solutions. The effective action becomes complex when pairs of charged particles are produced due to an electric field and curved spacetime. This may lead to a conjecture of one-to-one correspondence between the vacuum polarization (real part) and the vacuum persistence (imaginary part). We illustrate the one-loop effective action in a constant electric field in a Minkowski spacetime and in a uniform electric field in a two-dimensional (anti-) de Sitter space.

  4. Gauged Ads-Maxwell Algebra and Gravity

    NASA Astrophysics Data System (ADS)

    Durka, R.; Kowalski-Glikman, J.; Szczachor, M.

    We deform the anti-de Sitter algebra by adding additional generators {Z}ab, forming in this way the negative cosmological constant counterpart of the Maxwell algebra. We gauge this algebra and construct a dynamical model with the help of a constrained BF theory. It turns out that the resulting theory is described by the Einstein-Cartan action with Holst term, and the gauge fields associated with the Maxwell generators {Z}ab appear only in topological terms that do not influence dynamical field equations. We briefly comment on the extension of this construction, which would lead to a nontrivial Maxwell fields dynamics.

  5. Destabilizing Tachyonic Vacua at or above the BF Bound

    NASA Astrophysics Data System (ADS)

    Kanno, S.; Sasaki, M.; Soda, J.

    2012-07-01

    It is well known that tachyonic vacua in an asymptotically Anti-de Sitter (AdS) spacetime are classically stable if the mass squared is at or above the Breitenlohner and Freedman (BF) bound. We study the quantum stability of these tachyonic vacua in terms of instantons. We find a series of exact instanton solutions destabilizing tachyonic state at or above the BF bound in asymptotically AdS space. We also give an analytic formula for the decay rate and show that it is finite. Comparing our result with the well-known algebraic condition for the stability, we discuss stability conditions of tachyonic vacua at or above the BF bound.

  6. Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality.

    PubMed

    Dong, Xi; Harlow, Daniel; Wall, Aron C

    2016-07-08

    In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the anti-de Sitter/conformal field theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A, provided that they lie in its entanglement wedge. This is an improvement on existing reconstruction methods, which have at most succeeded in the smaller causal wedge. The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code.

  7. Complementarity of the maldacena and randall-sundrum pictures

    PubMed

    Duff; Liu

    2000-09-04

    We revive an old result, that one-loop corrections to the graviton propagator induce 1/r(3) corrections to the Newtonian gravitational potential, and compute the coefficient due to closed loops of the U(N) N = 4 super-Yang-Mills theory that arises in Maldacena's anti-de Sitter conformal field theory correspondence. We find exact agreement with the coefficient appearing in the Randall-Sundrum brane-world proposal. This provides more evidence for the complementarity of the two pictures.

  8. Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality

    NASA Astrophysics Data System (ADS)

    Dong, Xi; Harlow, Daniel; Wall, Aron C.

    2016-07-01

    In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the anti-de Sitter/conformal field theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A , provided that they lie in its entanglement wedge. This is an improvement on existing reconstruction methods, which have at most succeeded in the smaller causal wedge. The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code.

  9. Anisotropic charged fluids with Chaplygin equation of state in (2+1) dimension

    NASA Astrophysics Data System (ADS)

    Bhar, Piyali; Rahaman, Farook; Jawad, Abdul; Islam, Sayeedul

    2015-11-01

    Present paper provides a new non-singular model for anisotropic charged fluid sphere in (2+1)-dimensional anti de-Sitter spacetime corresponding to the exterior BTZ spacetime (Banados et al., Phys. Rev. Lett. 69:1849, 1992). The model is obtained by assuming Krori and Barua (KB) ansatz (Krori and Barua, J. Phys. A, Math. Gen., 8:508, 1975). To solve the Einstein-Maxwell field equations we choose modified Chaplygin gas. Various physical quantities have been discussed and from our analysis we show that our model satisfies all required physical conditions for representing compact stars.

  10. Gravity dual of spatially modulated phase

    SciTech Connect

    Nakamura, Shin; Ooguri, Hirosi; Park, Chang-Soon

    2010-02-15

    We show that the five-dimensional Maxwell theory with the Chern-Simons term is tachyonic in the presence of a constant electric field. When coupled to gravity, a sufficiently large Chern-Simons coupling causes instability of the Reissner-Nordstroem black holes in anti-de Sitter space. The instability happens only at nonvanishing momenta, suggesting a spatially modulated phase in the holographically dual quantum field theory in (3+1) dimensions, with spontaneous current generation in a helical configuration. The three-charge extremal black hole in the type IIB superstring theory on AdS{sub 5}xS{sup 5} barely satisfies the stability condition.

  11. Generalized Lorentz-Dirac equation for a strongly coupled gauge theory.

    PubMed

    Chernicoff, Mariano; García, J Antonio; Güijosa, Alberto

    2009-06-19

    We derive a semiclassical equation of motion for a "composite" quark in strongly coupled large-N_{c} N = 4 super Yang-Mills theory, making use of the anti-de Sitter space/conformal field theory correspondence. The resulting nonlinear equation incorporates radiation damping, and reduces to the standard Lorentz-Dirac equation for external forces that are small on the scale of the quark Compton wavelength, but has no self-accelerating or preaccelerating solutions. From this equation one can read off a nonstandard dispersion relation for the quark, as well as a Lorentz-covariant formula for its radiation rate.

  12. Holograms of Flat Space

    NASA Astrophysics Data System (ADS)

    Bagchi, Arjun; Grumiller, Daniel

    2013-07-01

    The holographic principle has a concrete realization in the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence. If this principle is a true fact about quantum gravity then it must also hold beyond AdS/CFT. In this paper, we address specifically holographic field theory duals of gravitational theories in asymptotically flat spacetimes. We present some evidence of our recent conjecture that three-dimensional (3d) conformal Chern-Simons gravity (CSG) with flat space boundary conditions is dual to an extremal CFT.

  13. Gravitational collapse, chaos in CFT correlators and the information paradox

    NASA Astrophysics Data System (ADS)

    Farahi, Arya; Pando Zayas, Leopoldo A.

    2014-06-01

    We consider gravitational collapse of a massless scalar field in asymptotically anti-de Sitter spacetime. Following the AdS/CFT dictionary we further study correlations in the field theory side by way of the Klein-Gordon equation of a probe scalar field in the collapsing background. We present evidence that in a certain regime the probe scalar field behaves chaotically, thus supporting Hawking's argument in the black hole information paradox proposing that although the information can be retrieved in principle, deterministic chaos impairs, in practice, the process of unitary extraction of information from a black hole. We emphasize that quantum chaos will change this picture. .

  14. Holography, heavy-quark free energy, and the QCD phase diagram

    SciTech Connect

    Colangelo, Pietro; Giannuzzi, Floriana; Nicotri, Stefano

    2011-02-01

    We use gauge/string duality to investigate the free energy of two static color sources (a heavy-quark-antiquark pair) in a Yang-Mills theory in strongly interacting matter, varying temperature and chemical potential. The dual space geometry is anti-de Sitter with a charged black hole to describe finite temperature and density in the boundary theory, and we also include a background warp factor to generate confinement. The resulting deconfinement line in the {mu}-T plane is similar to the one obtained by lattice and effective models of QCD.

  15. Exceptional F (4) higher-spin theory in AdS6 at one-loop and other tests of duality

    NASA Astrophysics Data System (ADS)

    Günaydin, Murat; Skvortsov, Evgeny; Tran, Tung

    2016-11-01

    We study the higher-spin gauge theory in six-dimensional anti-de Sitter space AdS6 that is based on the exceptional Lie superalgebra F (4). The relevant higher-spin algebra was constructed in arXiv:1409.2185. We determine the spectrum of the theory and show that it contains the physical fields of the Romans F (4) gauged supergravity. The full spectrum consists of an infinite tower of unitary supermultiplets of F (4) which extend the Romans multiplet to higher spins plus a single short supermultiplet.

  16. On the linear stability of solitons and hairy black holes with a negative cosmological constant: the even-parity sector

    NASA Astrophysics Data System (ADS)

    Winstanley, E.; Sarbach, O.

    2002-02-01

    Using a recently developed perturbation formalism based on curvature quantities, we complete our investigation of the linear stability of black holes and solitons with Yang-Mills hair and a negative cosmological constant. We show that those solutions which have no linear instabilities under odd- and even-parity spherically symmetric perturbations remain stable under even-parity, linear, non-spherically symmetric perturbations. Together with the result from a previous work, we have therefore established the existence of stable hairy black holes and solitons with anti-de Sitter asymptotic.

  17. String theory, quantum phase transitions, and the emergent Fermi liquid.

    PubMed

    Cubrović, Mihailo; Zaanen, Jan; Schalm, Koenraad

    2009-07-24

    A central problem in quantum condensed matter physics is the critical theory governing the zero-temperature quantum phase transition between strongly renormalized Fermi liquids as found in heavy fermion intermetallics and possibly in high-critical temperature superconductors. We found that the mathematics of string theory is capable of describing such fermionic quantum critical states. Using the anti-de Sitter/conformal field theory correspondence to relate fermionic quantum critical fields to a gravitational problem, we computed the spectral functions of fermions in the field theory. By increasing the fermion density away from the relativistic quantum critical point, a state emerges with all the features of the Fermi liquid.

  18. Electron star birth: a continuous phase transition at nonzero density.

    PubMed

    Hartnoll, Sean A; Petrov, Pavel

    2011-03-25

    We show that charged black holes in anti-de Sitter spacetime can undergo a third-order phase transition at a critical temperature in the presence of charged fermions. In the low temperature phase, a fraction of the charge is carried by a fermion fluid located a finite distance from the black hole. In the zero temperature limit, the black hole is no longer present and all charge is sourced by the fermions. The solutions exhibit the low temperature entropy density scaling s~T(2/z) anticipated from the emergent IR criticality of recently discussed electron stars.

  19. Ohm's law at strong coupling: S duality and the cyclotron resonance

    SciTech Connect

    Hartnoll, Sean A.; Herzog, Christopher P.

    2007-11-15

    We calculate the electrical and thermal conductivities and the thermoelectric coefficient of a class of strongly interacting 2+1-dimensional conformal field theories with anti-de Sitter space duals. We obtain these transport coefficients as a function of charge density, background magnetic field, temperature, and frequency. We show that the thermal conductivity and thermoelectric coefficient are determined by the electrical conductivity alone. At small frequency, in the hydrodynamic limit, we are able to provide a number of analytic formulas for the electrical conductivity. A dominant feature of the conductivity is the presence of a cyclotron pole. We show how bulk electromagnetic duality acts on the transport coefficients.

  20. Timelike Killing spinors in seven dimensions

    SciTech Connect

    Cariglia, Marco; Conamhna, Oisin A.P. Mac

    2004-12-15

    We employ the G-structure formalism to study supersymmetric solutions of minimal and SU(2) gauged supergravities in seven dimensions admitting Killing spinors with an associated timelike Killing vector. The most general such Killing spinor defines a SU(3) structure. We deduce necessary and sufficient conditions for the existence of a timelike Killing spinor on the bosonic fields of the theories, and find that such configurations generically preserve one out of 16 supersymmetries. Using our general supersymmetric ansatz we obtain numerous new solutions, including squashed or deformed anti-de Sitter solutions of the gauged theory, and a large class of Goedel-like solutions with closed timelike curves.

  1. Interacting shells in AdS spacetime and chaos

    NASA Astrophysics Data System (ADS)

    Brito, Richard; Cardoso, Vitor; Rocha, Jorge V.

    2016-07-01

    We study the simplest two-body problem in asymptotically anti-de Sitter spacetime: two, infinitely thin, concentric spherical shells of matter. We include only gravitational interaction between the two shells, but we show that the dynamics of this system is highly nontrivial. We observe prompt collapse to a black hole, delayed collapse and even perpetual oscillatory motion, depending on the initial location of the shells (or their energy content). The system exhibits critical behavior, and we show strong hints that it is also chaotic.

  2. First law of entanglement entropy in topologically massive gravity

    NASA Astrophysics Data System (ADS)

    Cheng, Long; Hung, Ling-Yan; Liu, Si-Nong; Zhou, Hong-Zhe

    2016-09-01

    In this paper we explore the validity of the first law of entanglement entropy in the context of topologically massive gravity (TMG). We find that the variation of the holographic entanglement entropy under perturbation from the pure anti-de Sitter background satisfies the first law upon imposing the bulk equations of motion in a given time slice, despite the appearance of instabilities in the bulk for generic gravitational Chern-Simons coupling μ . The Noether-Wald entropy is different from the holographic entanglement entropy in a general boosted frame. However, this discrepancy does not affect the entanglement first law.

  3. Vacuum energy in asymptotically flat 2 + 1 gravity

    NASA Astrophysics Data System (ADS)

    Miskovic, Olivera; Olea, Rodrigo; Roy, Debraj

    2017-04-01

    We compute the vacuum energy of three-dimensional asymptotically flat space based on a Chern-Simons formulation for the Poincaré group. The equivalent action is nothing but the Einstein-Hilbert term in the bulk plus half of the Gibbons-Hawking term at the boundary. The derivation is based on the evaluation of the Noether charges in the vacuum. We obtain that the vacuum energy of this space has the same value as the one of the asymptotically flat limit of three-dimensional anti-de Sitter space.

  4. Divergences and boundary modes in $ \\mathcal{N}=8 $ supergravity

    SciTech Connect

    Larsen, Finn; Lisbao, Pedro

    2016-01-07

    We reconsider the one loop divergence of $ \\mathcal{N}=8 $ supergravity in four dimensions. We compute the finite effective potential of $ \\mathcal{N}=8 $ anti-deSitter supergravity and interpret it as logarithmic running of the cosmological constant. We show that quantum inequivalence between fields that are classically dual is due to boundary modes in AdS4. In conclusion, the boundary modes are important in global AdS4 but not in thermal AdS4 since these geometries have different Euler characteristic.

  5. Implication of Spatial and Temporal Variations of the Fine-Structure Constant

    NASA Astrophysics Data System (ADS)

    Feng, Sze-Shiang; Yan, Mu-Lin

    2016-02-01

    Temporal and spatial variations of fine-structure constant α ≡ e2/hbar c in cosmology have been reported in analysis of combination Keck and VLT data. This paper studies the variations based on consideration of basic spacetime symmetry in physics. Both laboratory α 0 and distant α z are deduced from relativistic spectrum equations of atoms (e.g., hydrogen atom) defined in inertial reference systems. When Einstein's Λ≠0, the metric of local inertial reference systems in SM of cosmology is Beltrami metric instead of Minkowski, and the basic spacetime symmetry has to be de Sitter (dS) group. The corresponding special relativity (SR) is dS-SR. A model based on dS-SR is suggested. Comparing the predictions on α-varying with the data, the parameters are determined. The best-fit dipole mode in α's spatial varying is reproduced by this dS-SR model. α-varyings in whole sky are also studied. The results are generally in agreement with the estimations of observations. The main conclusion is that the phenomenon of α-varying cosmologically with dipole mode dominating is due to the de Sitter (or anti de Sitter) spacetime symmetry with a Minkowski point in an extended special relativity called de Sitter invariant special relativity (dS-SR) developed by Dirac-Inönü-Wigner-Gürsey-Lee-Lu-Zou-Guo.

  6. Crystal Chemical Substitutions of YBa2Cu3O7-d to Enhance Flux Pinning (Postprint)

    DTIC Science & Technology

    2012-02-01

    Cassinese, R. Di Capua, E. Di Gennaro, M . Iavarone, M.G. Maglione , R. Vaglio, Physica C 372-376 (2002) 703-705. X. Qi, M . Soorie, Z. Lockman, J.L...eserved. ISBN 1-59454-305-4 CRYSTAL CHEMICAL SUBSTITUTIO NS OF YBa2Cu30,-6 TO ENHANCE FLUX PINNING T. J. Haugan, J. C. Toli.Wer, J. M . Evans, J...RE substitutions for Y and/or Ba. B asic structural and physical properties of the RE and I I 194 T. J. Haugan, J. C. Tolliver, J. M . Evans and

  7. HALO7D: Disentangling the Milky Way Accretion History with Observations in 7 Dimensions

    NASA Astrophysics Data System (ADS)

    Cunningham, Emily C.; Deason, Alis; Guhathakurta, Puragra; Rockosi, Constance M.; Van Der Marel, Roeland P.; Sohn, S. Tony; HSTPROMO, HALO7D

    2016-01-01

    The Milky Way (MW) is shrouded in a faint metal-poor stellar halo. Its structure and kinematics provide a unique archaeological record of the MW's formation, past evolution, and accretion history. These data also help us constrain the dark matter mass out to large radii (50 to 100 kpc). However, studies of the MW stellar halo are hindered by observational constraints. Beyond D~10 kpc, our knowledge of the MW halo is limited to line of sight velocities and rare tracer populations (blue horizontal branch and red giant branch stars). We aim to address these limitations using highly accurate HST-measured proper motions and very deep (8-24 hour integrations) Keck DEIMOS spectroscopy of MW main sequence turn-off stars in the CANDELS fields. By combining these two datasets, we can obtain 6D phase-space information plus chemical abundances (7 "Dimensions") for our halo stars. This survey, which will be unique even in the era of Gaia, will vastly improve our understanding of the Milky Way structure, evolution and mass in a way that neither the HST proper motions nor Keck spectroscopy can do on their own.

  8. Flux Pinning Behavior of Incomplete Multilayered Lattice Structures in YBa(2)Cu(3)O(7-d)

    DTIC Science & Technology

    2004-11-01

    nanopatches of CeO2 (lower) for longer (left) and shorter (right) deposition times. It can be seen that Y2O3 particles are much smaller as compared to...134.131.125.49. Redistribution subject to(see Fig. 2). However, significant exceptions occur in the resulting data for the nanopatches of CeO2 at...typical YBCO and nanoparticulate pinning by Y211 or Y2O3. The natural assumption is that the CeO2 nanopatches result in decoupling of many of the

  9. A-7D Pitot-Static System Calibration and AIMS System Tests

    DTIC Science & Technology

    1973-05-01

    appreciation to Captain Robert E. Tyree and Mr. Donald J. Dowden for their assistance in preparing this report. This evaluation was conducted under...IMS KCAS kHz KIAS KTAS LDGP LTV indicated pressure altitude in the ft pneumatic (STANDBY) mode indicated pressure altitude corrected ft...for instrument error (not corrected for pressure error) in the pneumatic (STANDBY) mode indicated pressure altitude on the ft HUD indicated

  10. Black holes with su(N) gauge field hair and superconducting horizons

    NASA Astrophysics Data System (ADS)

    Shepherd, Ben L.; Winstanley, Elizabeth

    2017-01-01

    We present new planar dyonic black hole solutions of the su(N) Einstein-Yang-Mills equations in asymptotically anti-de Sitter space-time, focussing on su(2) and su(3) gauge groups. The magnetic part of the gauge field forms a condensate close to the planar event horizon. We compare the free energy of a non-Abelian hairy black hole with that of an embedded Reissner-Nordström-anti-de Sitter (RN-AdS) black hole having the same Hawking temperature and electric charge. We find that the hairy black holes have lower free energy. We present evidence that there is a phase transition at a critical temperature, above which the only solutions are embedded RN-AdS black holes. At the critical temperature, an RN-AdS black hole can decay into a hairy black hole, and it is thermodynamically favourable to do so. Working in the probe limit, we compute the frequency-dependent conductivity, and find that enlarging the gauge group from su(2) to su(3) eliminates a divergence in the conductivity at nonzero frequency.

  11. Tunneling from a Minkowski vacuum to an AdS vacuum: A new thin-wall regime

    NASA Astrophysics Data System (ADS)

    Masoumi, Ali; Paban, Sonia; Weinberg, Erick J.

    2016-07-01

    Using numerical and analytic methods, we study quantum tunneling from a Minkowski false vacuum to an anti-de Sitter true vacuum. Scanning the parameter space of theories with quartic and nonpolynomial potentials, we find that for any given potential tunneling is completely quenched if gravitational effects are made sufficiently strong. For potentials where ɛ , the energy density difference between the vacua, is small compared to the barrier height, this occurs in the thin-wall regime studied by Coleman and De Luccia. However, we find that other potentials, possibly with ɛ much greater than the barrier height, produce a new type of thin-wall bounce when gravitational effects become strong. We show that the critical curve that bounds the region in parameter space where the false vacuum is stable can be found by a computationally simple overshoot/undershoot argument. We discuss the treatment of boundary terms in the bounce calculation and show that, with proper regularization, one obtains an identical finite result for the tunneling exponent regardless of whether or not these are included. Finally, we briefly discuss the extension of our results to transitions between anti-de Sitter vacua.

  12. From Lorentzian to Galilean (2+1) gravity: Drinfelʼd doubles, quantization and noncommutative spacetimes

    NASA Astrophysics Data System (ADS)

    Ballesteros, Ángel; Herranz, Francisco J.; Naranjo, Pedro

    2014-12-01

    It is shown that the canonical classical r-matrix arising from the Drinfel'd double (DD) structure underlying the two-fold centrally extended (2+1) Galilean and Newton-Hooke (NH) Lie algebras (with either zero or non-zero cosmological constant Λ, respectively) originates as a well-defined non-relativistic contraction of a specific class of canonical r-matrices associated with the DD structure of the (2+1) (anti)-de Sitter Lie algebra. The full quantum group structure associated with such (2+1) Galilean and NH DD is presented, and the corresponding noncommutative spacetimes are shown to contain a commuting ‘absolute time’ coordinate {{\\hat{x}}0} together with two noncommutative space coordinates ({{\\hat{x}}1},{{\\hat{x}}2}), whose commutator is a function of the cosmological constant Λ and of the (central) ‘quantum time’ coordinate {{\\hat{x}}0}. Thus, the Chern-Simons approach to Galilean (2+1) gravity can be consistently understood as the appropriate non-relativistic limit of the Lorentzian theory, and their associated quantum group symmetries (which do not fall into the family of so-called kappa-deformations) can also be derived from the (anti)-de Sitter quantum doubles through a well-defined quantum group contraction procedure.

  13. Canonical energy is quantum Fisher information

    NASA Astrophysics Data System (ADS)

    Lashkari, Nima; Van Raamsdonk, Mark

    2016-04-01

    In quantum information theory, Fisher Information is a natural metric on the space of perturbations to a density matrix, defined by calculating the relative entropy with the unperturbed state at quadratic order in perturbations. In gravitational physics, Canonical Energy defines a natural metric on the space of perturbations to spacetimes with a Killing horizon. In this paper, we show that the Fisher information metric for perturbations to the vacuum density matrix of a ball-shaped region B in a holographic CFT is dual to the canonical energy metric for perturbations to a corresponding Rindler wedge R B of Anti-de-Sitter space. Positivity of relative entropy at second order implies that the Fisher information metric is positive definite. Thus, for physical perturbations to anti-de-Sitter spacetime, the canonical energy associated to any Rindler wedge must be positive. This second-order constraint on the metric extends the first order result from relative entropy positivity that physical perturbations must satisfy the linearized Einstein's equations.

  14. Gravitational tension, spacetime pressure and black hole volume

    NASA Astrophysics Data System (ADS)

    Armas, Jay; Obers, Niels A.; Sanchioni, Marco

    2016-09-01

    We study the first law of black hole thermodynamics in the presence of surrounding gravitational fields and argue that variations of these fields are naturally incorporated in the first law by defining gravitational tension or gravitational binding energy. We demonstrate that this notion can also be applied in Anti-de Sitter spacetime, in which the surrounding gravitational field is sourced by a cosmological fluid, therefore showing that spacetime volume and gravitational tension encode the same physics as spacetime pressure and black hole volume. We furthermore show that it is possible to introduce a definition of spacetime pressure and black hole volume for any spacetime with characteristic length scales which does not necessarily require a cosmological constant sourcing Einstein equations. However, we show that black hole volume is non-universal in the flat spacetime limit, questioning its significance. We illustrate these ideas by studying the resulting black hole volume of Kaluza-Klein black holes and of a toy model for a black hole binary system in five spacetime dimensions (the black saturn solution) as well as of several novel perturbative black hole solutions. These include the higher-dimensional Kerr-Newman solution in Anti-de Sitter spacetime as well as other black holes in plane wave and Lifshitz spacetimes.

  15. The Einstein equations on the 3-brane world

    NASA Astrophysics Data System (ADS)

    Shiromizu, Tetsuya; Maeda, Kei-Ichi; Sasaki, Misao

    2000-07-01

    We carefully investigate the gravitational equations of the brane world, in which all the matter forces except gravity are confined on the 3-brane in a 5-dimensional spacetime with Z2 symmetry. We derive the effective gravitational equations on the brane, which reduce to the conventional Einstein equations in the low energy limit. From our general argument we conclude that the first Randall-Sundrum-type theory predicts that the brane with a negative tension is an antigravity world and hence should be excluded from the physical point of view. Their second-type theory where the brane has a positive tension provides the correct signature of gravity. In this latter case, if the bulk spacetime is exactly anti-de Sitter spacetime, generically the matter on the brane is required to be spatially homogeneous because of the Bianchi identities. By allowing deviations from anti-de Sitter spacetime in the bulk, the situation will be relaxed and the Bianchi identities give just the relation between the Weyl tensor and the energy momentum tensor. In the present brane world scenario, the effective Einstein equations cease to be valid during an era when the cosmological constant on the brane is not well defined, such as in the case of the matter dominated by the potential energy of the scalar field.

  16. Renormalized entanglement entropy

    NASA Astrophysics Data System (ADS)

    Taylor, Marika; Woodhead, William

    2016-08-01

    We develop a renormalization method for holographic entanglement entropy based on area renormalization of entangling surfaces. The renormalized entanglement en-tropy is derived for entangling surfaces in asymptotically locally anti-de Sitter spacetimes in general dimensions and for entangling surfaces in four dimensional holographic renor-malization group flows. The renormalized entanglement entropy for disk regions in AdS 4 spacetimes agrees precisely with the holographically renormalized action for AdS 4 with spherical slicing and hence with the F quantity, in accordance with the Casini-Huerta-Myers map. We present a generic class of holographic RG flows associated with deforma-tions by operators of dimension 3 /2 < Δ < 5 /2 for which the F quantity increases along the RG flow, hence violating the strong version of the F theorem. We conclude by explaining how the renormalized entanglement entropy can be derived directly from the renormalized partition function using the replica trick i.e. our renormalization method for the entangle-ment entropy is inherited directly from that of the partition function. We show explicitly how the entanglement entropy counterterms can be derived from the standard holographic renormalization counterterms for asymptotically locally anti-de Sitter spacetimes.

  17. Holographic correspondence applied to vector meson emission from a heavy accelerated nucleus

    SciTech Connect

    Hoodbhoy, Pervez

    2008-12-01

    We consider a classical source, moving on the 4D boundary of a 5D anti-de Sitter space, that is coupled to quantum fields residing in the bulk. Bremsstrahlung-like radiation of the corresponding quanta is shown to occur and the S matrix is derived assuming that the source is sufficiently massive so that recoil effects are negligible. As an illustrative example, using the anti-de Sitter hard-wall model, we consider vector mesons coupled to a heavy nucleus that is moved around at high speed in an accelerator ring. The meson radiation rate is found to be finite but small. Much higher accelerations, such as when a pair of heavy ions suffer an ultra peripheral collision, cause substantial emission of various excited vector mesons. Predictions are made for the spectrum of this radiation. A comparison is made against existing photon-pomeron fusion calculations for the transverse momentum spectra of rho mesons. These have the same overall shape as the recently measured transverse momentum distributions at RHIC.

  18. Strings on AdS wormholes

    SciTech Connect

    Ali, Mir; Ruiz, Frenny; Saint-Victor, Carlos; Vazquez-Poritz, Justin F.

    2009-08-15

    We consider the behavior of open strings on anti-de Sitter wormholes in Gauss-Bonnet theory, which are the Gauss-Bonnet gravity duals of a pair of field theories. A string with both endpoints on the same side of the wormhole describes two charges within the same field theory, which exhibit Coulomb interaction for small separation. On the other hand, a string extending through the wormhole describes two charges which live in different field theories, and they exhibit a springlike confining potential. A transition occurs when there is a pair of charges present within each field theory: for small separation each pair of charges exhibits Coulomb interaction, while for large separation the charges in the different field theories pair up and exhibit confinement. Two steadily-moving charges in different field theories can occupy the same location provided that their speed is less than a critical speed, which also plays the role of a subluminal speed limit. However, for some wormhole backgrounds, charges moving at the critical speed cannot occupy the same location and energy is transferred from the leading charge to the lagging one. We also show that strings on anti-de Sitter wormholes in supergravity theories without higher-derivative curvature terms can exhibit these properties as well.

  19. Stability analysis of lower dimensional gravastars in noncommutative geometry

    NASA Astrophysics Data System (ADS)

    Banerjee, Ayan; Hansraj, Sudan

    2016-11-01

    The Bañados et al. (Phys. Rev. Lett 69:1849, 1992), black hole solution is revamped from the Einstein field equations in (2 + 1)-dimensional anti-de Sitter spacetime, in a context of noncommutative geometry (Phys. Rev. D 87:084014, 2013). In this article, we explore the exact gravastar solutions in three-dimensional anti-de Sitter space given in the same geometry. As a first step we derive BTZ solution assuming the source of energy density as point-like structures in favor of smeared objects, where the particle mass M, is diffused throughout a region of linear size √{α } and is described by a Gaussian function of finite width rather than a Dirac delta function. We matched our interior solution to an exterior BTZ spacetime at a junction interface situated outside the event horizon. Furthermore, a stability analysis is carried out for the specific case when χ < 0. 214 under radial perturbations about the static equilibrium solutions. To give theoretical support we are also trying to explore their physical properties and characteristics.

  20. Stability in holographic theories with irrelevant deformations

    NASA Astrophysics Data System (ADS)

    Amsel, Aaron J.; Roberts, Matthew M.

    2013-04-01

    We investigate the nonperturbative stability of asymptotically anti-de Sitter gravity coupled to tachyonic scalar fields with mass near the Breitenlohner-Freedman bound. Such scalars are characterized by power-law radial decay near the anti-de Sitter boundary, and typical boundary conditions are “Dirichlet” (which fix the slower falloff mode) or “Neumann” (which fix the faster falloff mode) type. More generally though, these “designer gravity” theories admit a large class of boundary conditions defined by a functional relation between the two modes. While previous stability proofs have considered boundary conditions that are deformations of the Neumann theory, the goal of this paper is to analyze stability in designer gravity with boundary conditions that are irrelevant deformations of the Dirichlet theory. We obtain a lower bound on the energy using spinor charge methods and show that, for the most interesting class of such boundary conditions, the theory is always stable. We argue that the deformed theory flows to a new fixed point in the ultraviolet, which is just the Neumann theory. We also derive a corresponding “effective potential” that implies stability if it has a global minimum.

  1. Mass-loss of an isolated gravitating system due to energy carried away by gravitational waves with a cosmological constant

    NASA Astrophysics Data System (ADS)

    Saw, Vee-Liem

    2016-11-01

    We derive the asymptotic solutions for vacuum spacetimes with nonzero cosmological constant Λ , using the Newman-Penrose formalism. Our approach is based exclusively on the physical spacetime, i.e., we do not explicitly deal with conformal rescaling nor the conformal spacetime. By investigating the Schwarzschild-de Sitter spacetime in spherical coordinates, we subsequently stipulate the falloffs of the null tetrad and spin coefficients for asymptotically de Sitter spacetimes such that the terms which would give rise to the Bondi mass-loss due to energy carried by gravitational radiation (i.e., involving σo ) must be nonzero. After solving the vacuum Newman-Penrose equations asymptotically, we propose a generalization to the Bondi mass involving Λ and obtain a positive-definite mass-loss formula by integrating the Bianchi identity involving D'Ψ2 over a compact 2-surface on I . Whilst our original intention was to study asymptotically de Sitter spacetimes, the use of spherical coordinates implies that this readily applies for Λ <0 , and yields exactly the known asymptotically flat spacetimes when Λ =0 . In other words, our asymptotic vacuum solutions with Λ ≠0 reduce smoothly to those where Λ =0 , in spite of the distinct characters of I being spacelike, timelike, and null for de Sitter, anti-de Sitter, and Minkowski, respectively. Unlike for Λ =0 where no incoming radiation corresponds to setting Ψ0o=0 on some initial null hypersurface, for Λ ≠0 , no incoming radiation requires Ψ0o=0 everywhere.

  2. Probing extra dimension through gravitational wave observations of compact binaries and their electromagnetic counterparts

    NASA Astrophysics Data System (ADS)

    Yu, Hao; Gu, Bao-Min; Huang, Fa Peng; Wang, Yong-Qiang; Meng, Xin-He; Liu, Yu-Xiao

    2017-02-01

    The future gravitational wave (GW) observations of compact binaries and their possible electromagnetic counterparts may be used to probe the nature of the extra dimension. It is widely accepted that gravitons and photons are the only two completely confirmed objects that can travel along null geodesics in our four-dimensional space-time. However, if there exist extra dimensions and only GWs can propagate freely in the bulk, the causal propagations of GWs and electromagnetic waves (EMWs) are in general different. In this paper, we study null geodesics of GWs and EMWs in a five-dimensional anti-de Sitter space-time in the presence of the curvature of the universe. We show that for general cases the horizon radius of GW is longer than EMW within equal time. Taking the GW150914 event detected by the Advanced Laser Interferometer Gravitational-Wave Observatory and the X-ray event detected by the Fermi Gamma-ray Burst Monitor as an example, we study how the curvature k and the constant curvature radius l affect the horizon radii of GW and EMW in the de Sitter and Einstein-de Sitter models of the universe. This provides an alternative method for probing extra dimension through future GW observations of compact binaries and their electromagnetic counterparts.

  3. Tunneling probability for the birth of an asymptotically DeSitter universe with dust

    SciTech Connect

    Ferreira Filho, L. G.

    2010-11-12

    The description of the dynamics of the Universe at the Planck era is made through the quantization of a Friedmann-Robertson-Walker (FRW) model with positively curved spatial sections. The material content consists of a positive cosmological constant and a perfect fluid in the form of dust. The results show that the universe can emerge from its initial phase through a quantum tunneling mechanism.

  4. Family Support Services: Respite, Sitter, In-Home Program Training Manual.

    ERIC Educational Resources Information Center

    Arizona State Dept. of Economic Security, Phoenix.

    The manual is designed to provide basic information on disabilities to future respite providers. The first chapter examines the nature and characteristics of handicaps in general as well as specific types, such as cerebral palsy, deafness, mental retardation, and behavioral disabilities. The chapter also introduces changing social notions…

  5. Design of Optimal Low-Thrust Lunar Pole-Sitter Missions

    NASA Astrophysics Data System (ADS)

    Grebow, Daniel J.; Ozimek, Martin T.; Howell, Kathleen C.

    2011-01-01

    Using a thruster similar to Deep Space 1's NSTAR, pole-sitting low-thrust trajectories are discovered in the vicinity of the L 1 and L 2 libration points. The trajectories are computed with a seventh-degree Gauss-Lobatto collocation scheme that automatically positions thrusting and coasting arcs, and aligns the thruster as necessary to satisfy the problem constraints. The trajectories appear to lie on slightly deformed surfaces corresponding to the L 1 and L 2 halo orbit families. A collocation scheme is also developed that first incorporates spiraling out from low-Earth orbit, and finally spiraling down to a stable lunar orbit for continued uncontrolled surveillance of the lunar south pole. Using direct transcription via collocation, the pole-sitting coverage time is maximized to 554.18 days, and the minimum elevation angle associated with the optimal trajectory is 13.0°.

  6. Docile sitters and active fighters in paper wasps: a tale of two queens

    NASA Astrophysics Data System (ADS)

    Kardile, Sujata; Gadagkar, Raghavendra

    2002-02-01

    Ropalidia marginata and Ropalidia cyathiformis are sympatric, primitively eusocial paper wasps widely distributed in peninsular India. We compare the two species, especially their queens, in an attempt to begin to understand the role of the power of queens over their workers, in social organisation and evolution. Queens of R. marginata have lower levels of activity, rates of interactions and dominance behaviour, compared with queens of R. cyathiformis. For the same variables, R. marginata queens are either indistinguishable from or have lower values than their workers, while R. cyathiformis queens have higher values than their workers. R. marginata queens never occupy the top rank while R. cyathiformis queens are always at the top of the behavioural dominance hierarchies of their colonies. R. marginata queens thus do not appear to use dominance behaviour to suppress reproduction by their workers, while R. cyathiformis queens appear to do so. These different mechanisms used by the two queens to regulate worker reproduction give them different powers over their workers, because R. marginata queens are completely successful in suppressing reproduction by their nestmates while in R. cyathiformis colonies, other individuals also sometimes lay eggs. There is also some evidence that the different powers of the queens result in different mechanisms of regulation of worker foraging in the two species - decentralised, self-regulation in R. marginata and relatively more centralised regulation by the queen in R. cyathiformis. Thus we show here, perhaps for the first time, that the power of the queens over their workers can have important consequences for social organisation and evolution.

  7. Conserved charges and first law of thermodynamics for Kerr-de Sitter black holes

    NASA Astrophysics Data System (ADS)

    Hajian, Kamal

    2016-08-01

    Recently, a general method for calculating conserved charges for (black hole) solutions to generally covariant gravitational theories, in any dimensions and with arbitrary asymptotic behaviors has been introduced. Equipped with this method, which can be dubbed as "solution phase space method," we calculate mass and angular momentum for the Kerr-dS black holes. Furthermore, for any choice of horizons, associated entropy and the first law of thermodynamics are derived. Interestingly, according to insensitivity of the analysis to the chosen cosmological constant, the analysis unifies the thermodynamics of rotating stationary black holes in 4 (and other) dimensions with either AdS, flat or dS asymptotics. We extend the analysis to include electric charge, i.e. to the Kerr-Newman-dS black holes.

  8. "Lion Tamers and Baby Sitters": First-Year English Teachers' Perceptions of Their Undergraduate Teacher Preparation.

    ERIC Educational Resources Information Center

    O'Rourke, Bill

    1983-01-01

    Personal narratives from first-year English teachers reveal that the social system of the schools in which they teach, the instructional system and its accompanying curriculum requirements and restraints, and the nature of the student population become dominant in determining teachers' behavior and their attitudes toward teaching. (HOD)

  9. Electromagnetic Casimir densities for a cylindrical shell on de Sitter space

    NASA Astrophysics Data System (ADS)

    Saharian, A. A.; Manukyan, V. F.; Saharyan, N. A.

    2016-12-01

    Complete set of cylindrical modes is constructed for the electromagnetic field inside and outside a cylindrical shell in the background of (D + 1)-dimensional dS space-time. On the shell, the field obeys the generalized perfect conductor boundary condition. For the Bunch-Davies vacuum state, we evaluate the vacuum expectation values (VEVs) of the electric field squared and of the energy-momentum tensor. The shell-induced contributions are explicitly extracted. In this way, for points away from the shell, the renormalization is reduced to the one for the VEVs in the boundary-free dS bulk. As a special case, the VEVs are obtained for a cylindrical shell in the (D + 1)-dimensional Minkowski bulk. We show that the shell-induced contribution in the electric field squared is positive for both the interior and exterior regions. The corresponding Casimir-Polder forces are directed toward the shell. The vacuum energy-momentum tensor, in addition to the diagonal components, has a nonzero off-diagonal component corresponding to the energy flux along the direction normal to the shell. This flux is directed from the shell in both the exterior and interior regions. For points near the shell, the leading terms in the asymptotic expansions for the electric field squared and diagonal components of the energy-momentum tensor are obtained from the corresponding expressions in the Minkowski bulk replacing the distance from the shell by the proper distance in the dS bulk. The influence of the gravitational field on the local characteristics of the vacuum is essential at distances from the shell larger than the dS curvature radius. The results are extended for confining boundary conditions of flux tube models in QCD.

  10. Relativistic astrophysics. [studies of gravitational radiation in asymptotic de sitter space and post Newtonian approximation

    NASA Technical Reports Server (NTRS)

    Smalley, L. L.

    1975-01-01

    The coordinate independence of gravitational radiation and the parameterized post-Newtonian approximation from which it is extended are described. The general consistency of the field equations with Bianchi identities, gauge conditions, and the Newtonian limit of the perfect fluid equations of hydrodynamics are studied. A technique of modification is indicated for application to vector-metric or double metric theories, as well as to scalar-tensor theories.

  11. Experimental Labs for Start-Ups: The Role of the "Venture-Sitter"

    ERIC Educational Resources Information Center

    Matricano, Diego; Pietrobon, Alberto

    2010-01-01

    Curley and Formica's (2008, 2010) studies of high-expectation entrepreneurship focus on the role of "experimental laboratories" in promoting the start-up and successful development of high-expectation firms. Although it is not difficult to understand the potential usefulness of these experimental labs--business simulators in which skilled partners…

  12. Inflationary Dilatonic de Sitter Universe from { N} = 4 Super-Yang Mills Theory Perturbed by Scalars

    NASA Astrophysics Data System (ADS)

    Hurtado, John Quiroga

    In this paper a quantum { N} = 4 super-Yang Mills theory perturbed by dilaton-coupled scalars, is considered. The induced effective action for such a theory is calculated on a dilaton-gravitational background using the conformal anomaly found via AdS/CFT correspondence. Considering such an effective action (using the large N method) as a quantum correction to the classical gravity action with cosmological constant we study the effect from dilaton to the scale factor (which corresponds to the inflationary universe without dilaton). It is shown that, depending on the initial conditions for the dilaton, the dilaton may slow down, or accelerate, the inflation process. At late times, the dilaton is decaying exponentially. At the end of this work, we consider the question how the perturbation of the solution for the scale factor affects the stability of the solution for the equations of motion and therefore the stability of the Inflationary Universe, which could be eternal.

  13. New test of general relativity - Measurement of de Sitter geodetic precession rate for lunar perigee

    NASA Technical Reports Server (NTRS)

    Bertotti, Bruno; Ciufolini, Ignazio; Bender, Peter L.

    1987-01-01

    According to general relativity, the calculated rate of motion of lunar perigee should include a contribution of 19.2 msec/yr from geodetic precession. It is shown that existing analyses of lunar-laser-ranging data confirm the general-relativistic rate for geodetic precession with respect to the planetary dynamical frame. In addition, the comparison of earth-rotation results from lunar laser ranging and from VLBI shows that the relative drift of the planetary dynamical frame and the extragalactic VLBI reference frame is small. The estimated accuracy is about 10 percent.

  14. Dynamic spin correlations in 'stuffed' spin ice Ho(2+x)Ti(2-x)O(7-d)

    SciTech Connect

    Ehlers, Georg

    2008-02-01

    The magnetic correlations in 'stuffed' spin ice Ho{sub 2+x}Ti{sub 2-x}O{sub 7-{delta}} have been characterized using quasielastic neutron scattering. At temperatures above 1K , these correlations are short ranged in nature and dynamic on a picosecond to nanosecond time scale. As for the case of pure spin ice Ho{sub 2+x}Ti{sub 2-x}O{sub 7}, one can identify, above the freezing temperature, a quantum relaxation regime which is enhanced as it persists to even higher temperatures, T{approx}30-40K , than in the parent compound.

  15. 17 CFR 270.7d-1 - Specification of conditions and arrangements for Canadian management investment companies...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and arrangements for Canadian management investment companies requesting order permitting registration... arrangements for Canadian management investment companies requesting order permitting registration. (a) A management investment company organized under the laws of Canada or any province thereof may obtain an...

  16. 17 CFR 270.7d-1 - Specification of conditions and arrangements for Canadian management investment companies...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... and arrangements for Canadian management investment companies requesting order permitting registration... arrangements for Canadian management investment companies requesting order permitting registration. (a) A management investment company organized under the laws of Canada or any province thereof may obtain an...

  17. Slow and static spin correlations in Dy(2+x)Ti(2-x)O(7-d)

    SciTech Connect

    Gardner, Jason; Ehlers, Georg; Fouquet, Peter; Farago, Bela; Stewart, John Ross

    2011-01-01

    The static and dynamic spin correlations in the spin ices Dy{sub 2.3}Ti{sub 1.7}O{sub 6.85} and Dy{sub 2}Ti{sub 2}O{sub 7} have been studied in polarized neutron diffraction and neutron spin echo experiments. The measurements reveal that, below 100 mK, the magnetic scattering braodens and shifts to higher |Q| upon stuffing the pyrochlore lattice with additional Dy{sup 3+} ions. These observations can be related, by means of reverse Monte Carlo simulation, to the modified distribution of near-neighbour distances and an overall more antiferromagnetic character of the near-neighbour couplings. The dynamic measurements show that the spin correlations are slower in the stuffed system. These results will be discussed and compared to the holmium analogues.

  18. Structural Basis for the Binding of the Neutralizing Antibody, 7D11, to the Poxvirus L1 Protein

    DTIC Science & Technology

    2007-08-01

    enveloped particles, such as the humanized chimpanzee B5 antibodies (Chen et al., 2006), may serve as a replacement for vaccinia immune globulin and...Svitel, J., Schuck, P., Satterfield, W., Moss, B., Purcell, R., 2006. Chimpanzee / human mAbs to vaccinia virus B5 protein neutralize vaccinia and...frame, is the target of neutralizing antibodies and has been successfully used as a component of both protein subunit and DNA vaccines. L1-specific

  19. Spectral probes of the holographic Fermi ground state: Dialing between the electron star and AdS Dirac hair

    SciTech Connect

    Cubrovic, Mihailo; Liu Yan; Schalm, Koenraad; Sun Yawen; Zaanen, Jan

    2011-10-15

    We argue that the electron star and the anti-de Sitter (AdS) Dirac hair solution are two limits of the free charged Fermi gas in AdS. Spectral functions of holographic duals to probe fermions in the background of electron stars have a free parameter that quantifies the number of constituent fermions that make up the charge and energy density characterizing the electron star solution. The strict electron star limit takes this number to be infinite. The Dirac hair solution is the limit where this number is unity. This is evident in the behavior of the distribution of holographically dual Fermi surfaces. As we decrease the number of constituents in a fixed electron star background the number of Fermi surfaces also decreases. An improved holographic Fermi ground state should be a configuration that shares the qualitative properties of both limits.

  20. Towards a novel no-hair theorem for black holes

    SciTech Connect

    Hertog, Thomas

    2006-10-15

    We provide strong numerical evidence for a new no-scalar-hair theorem for black holes in general relativity, which rules out spherical scalar hair of static four-dimensional black holes if the scalar field theory, when coupled to gravity, satisfies the Positive Energy Theorem. This sheds light on the no-scalar-hair conjecture for Calabi-Yau compactifications of string theory, where the effective potential typically has negative regions but where supersymmetry ensures the total energy is always positive. In theories where the scalar tends to a negative local maximum of the potential at infinity, we find the no-scalar-hair theorem holds provided the asymptotic conditions are invariant under the full anti-de Sitter symmetry group.