Supersymmetric Kerr-anti-de Sitter solutions
Cvetic, Mirjam; Gao Peng; Simon, Joan
2005-07-15
We prove the existence of one quarter supersymmetric type IIB configurations that arise as nontrivial scaling solutions of the standard five-dimensional Kerr-anti-de Sitter black holes by the explicit construction of its Killing spinors. This neutral, spinning solution is asymptotic to the static anti-de Sitter space-time with cosmological constant -(1/l{sup 2}), it has two finite equal angular momenta J{sub 1}={+-}J{sub 2}, mass M=(1/l)(|J{sub 1}|+|J{sub 2}|) and a naked singularity. We also address the scaling limit associated with one-half supersymmetric solution with only one angular momentum.
Blackfolds in (anti)-de Sitter backgrounds
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.
Liu, James T.; Sabra, W.A.
2005-09-15
The boundary stress tensor approach has proven extremely useful in defining mass and angular momentum in asymptotically anti-de Sitter spaces with CFT duals. An integral part of this method is the use of boundary counterterms to regulate the gravitational action and stress tensor. In the presence of matter, however, ambiguities may arise that are related to the addition of possible finite counterterms. We demonstrate this explicitly for R-charged black holes in AdS{sub 5}, where introduction of a finite counterterm proportional to {phi}{sup 2} is necessary to properly reproduce the expected mass/charge relation for the black holes.
Colorful Horizons with Charge in Anti-de Sitter Space
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.
Small Kerr-anti-de Sitter black holes are unstable
Cardoso, Vitor; Dias, Oscar J.C.
2004-10-15
Superradiance in black hole spacetimes can trigger instabilities. Here we show that, due to superradiance, small Kerr-anti-de Sitter black holes are unstable. Our demonstration uses a matching procedure, in a long wavelength approximation.
NASA Astrophysics Data System (ADS)
Arzano, Michele; Gubitosi, Giulia; Magueijo, João; Amelino-Camelia, Giovanni
2015-07-01
We investigate the anti-de Sitter (AdS) counterpart to the well-studied de Sitter (dS) model for energy-momentum space, viz "κ -momentum space" space (with a structure based on the properties of the κ -Poincaré Hopf algebra). On the basis of previous preliminary results one might expect the two models to be complementary: dS exhibiting an invariant maximal spatial momentum but unbounded energy, AdS a maximal energy but unbounded momentum. If that were the case AdS momentum space could be used to implement a principle of maximal Planck-scale energy, just as several studies use dS momentum space to postulate of maximal Planck-scale spatial momentum. However, several unexpected features are uncovered in this paper, which limit the scope of the expected complementarity, and interestingly they take different forms in different coordinatizations of AdS momentum space. "Cosmological" AdS coordinates mimic the dS construction used for κ -momentum space, and produce a Carrol limit in the ultraviolet. However, unlike the κ -momentum space, the boundary of the covered patch breaks Lorentz invariance, thereby introducing a preferred frame. In "horospherical" coordinates we achieve full consistency with frame independence as far as boost transformations are concerned, but find that rotational symmetry is broken, leading to an anisotropic model for the speed of light. Finally, in "static" coordinates we find a way of deforming relativistic transformations that successfully enforces frame invariance and isotropy, and produces a Carrol limit in the ultraviolet. Our results are also relevant for a long-standing debate on whether or not coordinate redefinitions in momentum space lead to physically equivalent theories: our three proposals are evidently physically inequivalent, leading to alternative models of Planck-scale effects. As a corollary we study the UV running of the Hausdorff dimension of momentum space in the first and third model, obtaining different results.
The Schwinger mechanism in (Anti) de Sitter spacetimes
NASA Astrophysics Data System (ADS)
Samantray, Prasant
2016-04-01
We present a short and novel derivation of the Schwinger mechanism for particle pair production in 1 + 1 dimensional de Sitter and Anti de Sitter spacetimes. We work directly in the flat embedding space and derive the pair production rates in these spacetimes via instanton methods. The derivation is manifestly coordinate independent, and also lends support to the possible deep connection between two conceptually disparate quantum phenomena — Schwinger effect and the Davies-Unruh effect.
On electric field in anti-de Sitter spacetime
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.
Superradiant instabilities of asymptotically anti-de Sitter black holes
NASA Astrophysics Data System (ADS)
Green, Stephen R.; Hollands, Stefan; Ishibashi, Akihiro; Wald, Robert M.
2016-06-01
We study the linear stability of asymptotically anti-de Sitter black holes in general relativity in spacetime dimension d≥slant 4. Our approach is an adaptation of the general framework of Hollands and Wald, which gives a stability criterion in terms of the sign of the canonical energy, { E }. The general framework was originally formulated for static or stationary and axisymmetric black holes in the asymptotically flat case, and the stability analysis for that case applies only to axisymmetric perturbations. However, in the asymptotically anti-de Sitter case, the stability analysis requires only that the black hole have a single Killing field normal to the horizon and there are no restrictions on the perturbations (apart from smoothness and appropriate behavior at infinity). For an asymptotically anti-de Sitter black hole, we define an ergoregion to be a region where the horizon Killing field is spacelike; such a region, if present, would normally occur near infinity. We show that for black holes with ergoregions, initial data can be constructed such that { E }\\lt 0, so all such black holes are unstable. To obtain such initial data, we first construct an approximate solution to the constraint equations using the WKB method, and then we use the Corvino–Schoen technique to obtain an exact solution. We also discuss the case of charged asymptotically anti-de Sitter black holes with generalized ergoregions.
The anti-de Sitter spacetime as a time machine
NASA Astrophysics Data System (ADS)
Ahmed, Faizuddin; Bikash Hazarika, Bidyut; Sarma, Debojit
2016-07-01
We construct an axially symmetric spacetime admitting, after a certain instant, closed timelike curves (CTCs) indicating that it is a time-machine spacetime. The spacetime, which is locally anti-de Sitter, is a four-dimensional extension of the Misner space with identical causality-violating properties. In this spacetime, CTCs evolve from a casually well-behaved initial hypersurface.
Photon rockets in the (anti-)de Sitter universe
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.
Dirac fermions on an anti-de Sitter background
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.
Evanescent gravitons in warped anti-de Sitter space
NASA Astrophysics Data System (ADS)
Giribet, Gaston; Vásquez, Yerko
2016-01-01
Besides black holes, the phase space of three-dimensional massive gravity about warped anti-de Sitter space contains solutions that decay exponentially in time. They describe evanescent graviton configurations that, while governed by a wave equation with nonvanishing effective mass, do not carry net gravitational energy. Explicit examples of such solutions have been found in the case of topologically massive gravity; here, we generalize them to a much more general ghost-free massive deformation, with the difference being that the decay rate gets corrected due to the presence of higher-order terms.
Cosmic censorship of rotating Anti-de Sitter black hole
NASA Astrophysics Data System (ADS)
Gwak, Bogeun; Lee, Bum-Hoon
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.
Lightlike hypersurfaces along spacelike submanifolds in anti-de Sitter space
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.
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.
Generalized Gravitational Entropy for Warped Anti-de Sitter Space.
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. PMID:27419559
(Anti-) de Sitter electrically charged black-hole solutions in higher-derivative gravity
NASA Astrophysics Data System (ADS)
Lin, Kai; Qian, Wei-Liang; Pavan, A. B.; Abdalla, E.
2016-06-01
In this paper, static electrically charged black-hole solutions with cosmological constant are investigated in an Einstein-Hilbert theory of gravity with additional quadratic curvature terms. Beside the analytic Schwarzschild (Anti-) de Sitter solutions, non-Schwarzschild (Anti-) de Sitter solutions are also obtained numerically by employing the shooting method. The results show that there exist two groups of asymptotically (Anti-) de Sitter spacetimes for both charged and uncharged black holes. In particular, it was found that for uncharged black holes the first group can be reduced to the Schwarzschild (Anti-) de Sitter solution, while the second group is intrinsically different from a Schwarzschild (Anti-) de Sitter solution even when the charge and the cosmological constant become zero.
Gravitational collapse in asymptotically anti-de Sitter or de Sitter backgrounds
Madhav, T. Arun; Goswami, Rituparno; Joshi, Pankaj S.
2005-10-15
We study here the gravitational collapse of a matter cloud with a nonvanishing tangential pressure in the presence of a nonzero cosmological term {lambda}. It is investigated how {lambda} modifies the dynamics of the collapsing cloud and whether it affects the cosmic censorship. Conditions for bounce and singularity formation are derived. It is seen that when the tangential pressure vanishes, the bounce and singularity conditions reduce to the dust case studied earlier. The collapsing interior is matched to an exterior which is asymptotically de Sitter or anti-de Sitter, depending on the sign of the cosmological constant. The junction conditions for matching the cloud to the exterior are specified. The effect of {lambda} on apparent horizons is studied in some detail and the nature of central singularity is analyzed. The visibility of singularity and implications for the cosmic censorship conjecture are discussed. It is shown that for a nonvanishing cosmological constant, both black hole and naked singularities do form as collapse end states in spacetimes which are asymptotically de Sitter or anti-de Sitter.
NUT charge, anti-de Sitter space, and entropy
NASA Astrophysics Data System (ADS)
Hawking, S. W.; Hunter, C. J.; Page, Don N.
1999-02-01
It has been proposed that spacetimes with a U(1) isometry group have contributions to the entropy from Misner strings as well as from the area of d-2 dimensional fixed point sets. In this paper we test this proposal by constructing Taub-NUT-AdS and Taub-bolt-AdS solutions which are examples of a new class of asymptotically locally anti-de Sitter space. We find that with the additional contribution from the Misner strings, we exactly reproduce the entropy calculated from the action by the usual thermodynamic relations. This entropy has the right parameter dependence to agree with the entropy of a conformal field theory on the boundary, which is a squashed three-sphere, at least in the limit of large squashing. However, the conformal field theory and the normalization of the entropy remain to be determined.
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).
Normalized energy eigenspinors of the Dirac field on anti-de Sitter spacetime
NASA Astrophysics Data System (ADS)
Cotăescu, Ion I.
1999-12-01
I show how to derive the normalized energy eigenspinors of the free Dirac field on anti-de Sitter spacetime by using a Cartesian tetrad gauge where the separation of spherical variables can be done as in special relativity.
Chemical potential driven phase transition of black holes in anti-de Sitter space
NASA Astrophysics Data System (ADS)
Galante, Mario; Giribet, Gaston; Goya, Andrés; Oliva, Julio
2015-11-01
Einstein-Maxwell theory conformally coupled to a scalar field in D dimensions may exhibit a phase transition at low temperature whose end point is an asymptotically anti-de Sitter black hole with a scalar field profile that is regular everywhere outside and on the horizon. This provides a tractable model to study the phase transition of hairy black holes in anti-de Sitter space in which the backreaction on the geometry can be solved analytically.
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.
Semiclassical quantization of circular strings in de Sitter and anti--de Sitter spacetimes
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.
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.
Semiclassical (qft) and Quantum (string) Anti-De Sitter Regimes:. New Results
NASA Astrophysics Data System (ADS)
Bouchareb, A.; Ramón Medrano, M.; Sánchez, N. G.
We compute the quantum string entropy Ss(m, H) from the microscopic string density of states ρs(m, H) of mass m in Anti-de Sitter space-time. For high m, (high Hm → c/α‧), no phase transition occurs at the Anti-de Sitter string temperature Ts = (1/2πkB)Lclc2/α‧, which is higher than the flat space (Hagedorn) temperature ts. (Lcl = c/H, the Hubble constant H acts as producing a smaller string constant α‧ and thus, a higher tension). Ts is the precise quantum dual of the semiclassical (QFT) Anti-de Sitter temperature scale Tsem = ℏc/(2πkBLcl). We compute the quantum string emission σstring by a black hole in Anti-de Sitter (or asymptotically Anti-de Sitter) space-time (bhAdS). For Tsem bhAdS ≪ Ts (early evaporation stage), it shows the QFT Hawking emission with temperature Tsem bhAdS (semiclassical regime). For Tsem bhAdS → Ts, it exhibits a phase transition into a Anti-de Sitter string state of size Ls = ls2/L_ cl, (ls = √ hbar α '/c}), and Anti-de Sitter string temperature Ts. New string bounds on the black hole emerge in the bhAdS string regime. The bhAdS string regime determines a maximal value for H : Hmax = 0.841c/ls. The minimal black hole radius in Anti-de Sitter space-time turns out to be rg min = 0.841ls, and is larger than the minimal black hole radius in de Sitter space-time by a numerical factor equal to 2.304. We find a new formula for the full AdS entropy Ssem(H), as a function of the usual Bekenstein-Hawking entropy S sem(0)(H). For Lcl ≫ ℓPlanck, i.e. for low H ≪ c/ℓPlanck, or classical regime, S sem(0)(H) is the leading term with its logarithmic correction, but for high H ≥ c/ℓPlanck or quantum regime, no phase transition operates, in contrast to de Sitter space, and the entropy Ssem(H) is very different from the Bekenstein-Hawking term S sem(0)(H).
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.
Anti-De Sitter Island-Universes from 5d Standing Waves
NASA Astrophysics Data System (ADS)
Gogberashvili, Merab; Singleton, Douglas
We construct simple standing wave solutions in a 5D spacetime with a ghost-like scalar field. The nodes of these standing waves are "islands" of 4D anti-de Sitter spacetime. In the case of increasing (decreasing) warp factor, there are a finite (infinite) number of nodes and thus a finite (infinite) number of anti-de Sitter island-universes having different gravitational and cosmological constants. This is similar to the landscape models, which postulate a large number of universes with different parameters.
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.
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.
Entanglement entropy of black holes and anti-de Sitter space/conformal-field-theory correspondence.
Solodukhin, Sergey N
2006-11-17
A recent proposal by Ryu and Takayanagi for a holographic interpretation of entanglement entropy in conformal field theories dual to supergravity on anti-de Sitter space is generalized to include entanglement entropy of black holes living on the boundary of anti-de Sitter space. The generalized proposal is verified in boundary dimensions d=2 and d=4 for both the uv-divergent and uv-finite terms. In dimension d=4 an expansion of entanglement entropy in terms of size L of the subsystem outside the black hole is considered. A new term in the entropy of dual strongly coupled conformal-field theory, which universally grows as L(2)lnL and is proportional to the value of the obstruction tensor at the black hole horizon, is predicted. PMID:17155672
Stability of anti-de sitter space in Einstein-Gauss-Bonnet gravity.
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. PMID:25763946
The anti-de Sitter Gott universe: a rotating BTZ wormhole
NASA Astrophysics Data System (ADS)
Holst, Sören; Matschull, Hans-Jürgen
1999-10-01
Recently, it has been shown that a (2 + 1)-dimensional black hole can be created by the collapse of two colliding massless particles in an otherwise empty anti-de Sitter space. Here we generalize this construction to the case of a non-zero impact parameter. The resulting spacetime, which may be regarded as a Gott universe in an anti-de Sitter background, contains closed timelike curves. By treating these as singular we are able to interpret our solution as a rotating black hole, hence providing a link between the Gott universe and the BTZ black hole. When analysing the spacetime we see how the full causal structure of the interior can be almost completely inferred just from considerations of the conformal boundary.
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.
Resonant Dynamics and the Instability of Anti-de Sitter Spacetime.
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. PMID:26340178
Anti-de Sitter-wave solutions of higher derivative theories.
Gürses, Metin; Hervik, Sigbjørn; Şişman, Tahsin Çağrı; Tekin, Bayram
2013-09-01
We show that the recently found anti-de Sitter (AdS)-plane and AdS-spherical wave solutions of quadratic curvature gravity also solve the most general higher derivative theory in D dimensions. More generally, we show that the field equations of such theories reduce to an equation linear in the Ricci tensor for Kerr-Schild spacetimes having type-N Weyl and type-N traceless Ricci tensors. PMID:25166648
Resonant Dynamics and the Instability of Anti-de Sitter Spacetime
NASA Astrophysics Data System (ADS)
Bizoń, Piotr; Maliborski, Maciej; Rostworowski, Andrzej
2015-08-01
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.
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.
Toroidal configurations of perfect fluid in the Reissner-Nordström-(anti-)de Sitter spacetimes
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.
Generic cosmic-censorship violation in anti-de Sitter space.
Hertog, Thomas; Horowitz, Gary T; Maeda, Kengo
2004-04-01
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. PMID:15089592
Anyonic Strings and Membranes in Anti-de Sitter Space and Dual Aharonov-Bohm Effects
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.
Bjorken flow from an anti-de Sitter space Schwarzschild black hole.
Alsup, James; Siopsis, George
2008-07-18
We consider a large black hole in asymptotically anti-de Sitter spacetime of arbitrary dimension with a Minkowski boundary. By performing an appropriate slicing as we approach the boundary, we obtain via holographic renormalization a gauge theory fluid obeying Bjorken hydrodynamics in the limit of large longitudinal proper time. The metric we obtain reproduces to leading order the metric recently found as a direct solution of the Einstein equations in five dimensions. Our results are also in agreement with recent exact results in three dimensions. PMID:18764245
Massive higher derivative gravity in D-dimensional anti-de Sitter spacetimes
Guellue, Ibrahim; Tekin, Bayram
2009-09-15
We find the propagator and calculate the tree level scattering amplitude between two covariantly conserved sources in an anti-de Sitter background for the most general D-dimensional quadratic, four-derivative, gravity with a Pauli-Fierz mass. We also calculate the Newtonian potential for various limits of the theory in flat space. We show how the recently introduced three-dimensional New Massive Gravity is uniquely singled out among higher derivative models as a (tree level) unitary model and that its Newtonian limit is equivalent to that of the usual massive gravity in flat space.
Anti-de Sitter-Space/Conformal-Field-Theory Casimir Energy for Rotating Black Holes
Gibbons, G.W.; Perry, M.J.; Pope, C.N.
2005-12-02
We show that, if one chooses the Einstein static universe as the metric on the conformal boundary of Kerr-anti-de Sitter spacetime, then the Casimir energy of the boundary conformal field theory can easily be determined. The result is independent of the rotation parameters, and the total boundary energy then straightforwardly obeys the first law of thermodynamics. Other choices for the metric on the conformal boundary will give different, more complicated, results. As an application, we calculate the Casimir energy for free self-dual tensor multiplets in six dimensions and compare it with that of the seven-dimensional supergravity dual. They differ by a factor of 5/4.
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.
Asymptotically (anti)-de Sitter solutions in Gauss-Bonnet gravity without a cosmological constant
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.
NASA Astrophysics Data System (ADS)
Yin, Shaoyu; Wang, Bin; Mann, Robert; Lee, Chong Oh; Lin, Chi-Yong; Su, Ru-Keng
2010-09-01
We investigate the stability of a new warped black string with nontrivial topologies in five-dimensional anti-de Sitter spacetime. After studying the linear gravitational perturbation, we find that this black string is unstable when the Kaluza-Klein mass falls in a certain range, and the instability exists for all topological spacetimes.
From the Anti-Yang Model to the Anti-Snyder Model and Anti-De Sitter Special Relativity
NASA Astrophysics Data System (ADS)
Qi, Wei-Jun; Ren, Xin-An
2013-04-01
Based on Yang's quantized space-time model, a complete Yang model from (5+1)-dimensional space with Minkowski signature is discussed using the projective geometry method and Dirac procedure. We introduce an anti-Yang model and an anti-Snyder model to discuss the duality relations between the anti-Snyder model and anti-de Sitter special relativity.
Reissner–Nordström Anti-de Sitter Black Holes in Mimetic F(R) Gravity
NASA Astrophysics Data System (ADS)
Oikonomou, V. K.
2016-05-01
In this paper we study under which conditions the Reissner-Nordstr\\"om-anti de Sitter black hole can be a solution of the vacuum mimetic $F(R)$ gravity with Lagrange multiplier and mimetic scalar potential. As we demonstrate, the resulting picture in the mimetic $F(R)$ gravity case, is different in comparison to the ordinary $F(R)$ gravity case, with the two descriptions resulting to a different set of constraints that need to hold true. We also investigate the metric perturbations in the mimetic $F(R)$ gravity case, for the Reissner-Nordstr\\"om-anti de Sitter black hole metric, at first order of the perturbed variables. Interestingly enough, the resulting equations are identical to the ones corresponding to the ordinary $F(R)$ gravity Reissner-Nordstr\\"om-anti de Sitter black hole, at least at first order. We attribute this feature to the particular form of the Reissner-Nordstr\\"om-anti de Sitter metric, and we speculate for which cases there could be differences between the mimetic and non-mimetic case. Since the perturbation equations are the same for the two cases, it is possible to have black hole instabilities in the mimetic $F(R)$ gravity case too, which can be interpreted as anti-evaporation of the black hole.
Strings in five-dimensional anti-de Sitter space with a symmetry
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.
Nonlinear Evolution and Final Fate of Charged Anti-de Sitter Black Hole Superradiant Instability.
Bosch, Pablo; Green, Stephen R; Lehner, Luis
2016-04-01
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. PMID:27104693
Hawking evaporation time scale of topological black holes in anti-de Sitter spacetime
NASA Astrophysics Data System (ADS)
Ong, Yen Chin
2016-02-01
It was recently pointed out that if an absorbing boundary condition is imposed at infinity, an asymptotically anti-de Sitter Schwarzschild black hole with a spherical horizon takes only a finite amount of time to evaporate away even if its initial mass is arbitrarily large. We show that this is a rather generic property in AdS spacetimes: regardless of their horizon topologies, neutral AdS black holes in general relativity take about the same amount of time to evaporate down to the same size of order L, the AdS length scale. Our discussion focuses on the case in which the black hole has toral event horizon. A brief comment is made on the hyperbolic case, i.e. for black holes with negatively curved horizons.
Unique Continuation from Infinity in Asymptotically Anti-de Sitter Spacetimes
NASA Astrophysics Data System (ADS)
Holzegel, Gustav; Shao, Arick
2016-02-01
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.
Collapse of Self-Interacting Scalar Field in Anti-de Sitter Space
NASA Astrophysics Data System (ADS)
Cai, Rong-Gen; Ji, Li-Wei; Yang, Run-Qiu
2016-03-01
The gravitational collapse of a massless scalar field with a self-interaction term λφ4 in anti-de Sitter space is investigated. We numerically investigate the effect of the self-interaction term on the critical amplitudes, forming time of apparent horizon, stable island, and energy transformation. The results show that a positive λ suppresses the formation of black hole, while a negative λ enhances the process. We define two susceptibilities to characterize the effect of the self-interaction on the black hole formation, and find that near the critical amplitude, there exists a universal scaling relation with the critical exponent α ≈ 0.74 for the time of black hole formation. Supported by the National Natural Science Foundation of China under Grant Nos. 11375247 and 11435006
Homoclinic accretion solutions in the Schwarzschild-anti-de Sitter space-time
NASA Astrophysics Data System (ADS)
Mach, Patryk
2015-04-01
The aim of this paper is to clarify the distinction between homoclinic and standard (global) Bondi-type accretion solutions in the Schwarzschild-anti-de Sitter space-time. The homoclinic solutions have recently been discovered numerically for polytropic equations of state. Here I show that they exist also for certain isothermal (linear) equations of state, and an analytic solution of this type is obtained. It is argued that the existence of such solutions is generic, although for sufficiently relativistic matter models (photon gas, ultrahard equation of state) there exist global solutions that can be continued to infinity, similarly to standard Michel's solutions in the Schwarzschild space-time. In contrast to that global solutions should not exist for matter models with a nonvanishing rest-mass component, and this is demonstrated for polytropes. For homoclinic isothermal solutions I derive an upper bound on the mass of the black hole for which stationary transonic accretion is allowed.
Charged anti-de Sitter scalar-tensor black holes and their thermodynamic phase structure
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.
Simulation of Black Hole Collisions in Asymptotically anti-de Sitter Spacetimes
NASA Astrophysics Data System (ADS)
Bantilan, Hans; Romatschke, Paul
2015-04-01
The main purpose of this talk is to describe, in detail, the necessary ingredients for achieving stable Cauchy evolution of black hole collisions in asymptotically anti-de Sitter (AdS) spacetimes. I will begin by motivating this program in terms of the heavy-ion physics it is intended to clarify. I will then give an overview of asymptotically AdS spacetimes, the mapping to the dual conformal field theory on the AdS boundary, and the method we use to numerically solve the fully non-linear Einstein field equations with AdS boundary conditions. As a concrete example of these ideas, I will describe the first proof of principle simulation of stable AdS black hole mergers in 5 dimensions.
Holographic thermalization, stability of anti-de sitter space, and the Fermi-Pasta-Ulam paradox.
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. PMID:25170699
Simulation of Black Hole Collisions in Asymptotically Anti-de Sitter Spacetimes
NASA Astrophysics Data System (ADS)
Bantilan, Hans; Romatschke, Paul
2015-02-01
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.
Nonlinear Evolution and Final Fate of Charged Anti-de Sitter Black Hole Superradiant Instability
NASA Astrophysics Data System (ADS)
Bosch, Pablo; Green, Stephen R.; Lehner, Luis
2016-04-01
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.
Anti-De Sitter Space, Thermal Phase Transition, and Confinement in Gauge Theories
NASA Astrophysics Data System (ADS)
Witten, Edward
2014-03-01
The correspondence between supergravity (and string theory) on AdS space and boundary conformal field theory relates the thermodynamics of N = 4 super Yang-Mills theory in four dimensions to the thermodynamics of Schwarzschild black holes in Anti-de Sitter space. In this description, quantum phenomena such as the spontaneous breaking of the center of the gauge group, magnetic confinement, and the mass gap are coded in classical geometry. The correspondence makes it manifest that the entropy of a very large AdS Schwarzschild black hole must scale "holographically" with the volume of its horizon. By similar methods, one can also make a speculative proposal for the description of large N gauge theories in four dimensions without supersymmetry.
Abundant stable gauge field hair for black holes in anti-de Sitter space.
Baxter, J E; Helbling, Marc; Winstanley, Elizabeth
2008-01-11
We present new hairy black hole solutions of SU(N) Einstein-Yang-Mills (EYM) theory in asymptotically anti-de Sitter (AdS) space. These black holes are described by N+1 independent parameters and have N-1 independent gauge field degrees of freedom. Solutions in which all gauge field functions have no zeros exist for all N, and for a sufficiently large (and negative) cosmological constant. At least some of these solutions are shown to be stable under classical, linear, spherically symmetric perturbations. Therefore there is no upper bound on the amount of stable gauge field hair with which a black hole in AdS can be endowed. PMID:18232751
New Features of Gravitational Collapse in Anti-de Sitter Spacetimes.
Santos-Oliván, Daniel; Sopuerta, Carlos F
2016-01-29
Gravitational collapse of a massless scalar field in spherically symmetric anti-de Sitter (AdS) spacetimes presents a new phenomenology with a series of critical points whose dynamics is discretely self-similar as in the asymptotically flat case. Each critical point is the limit of a branch of scalar field configurations that have bounced off the AdS boundary a fixed number of times before forming an apparent horizon. We present results from a numerical study that focus on the interfaces between branches. We find that there is a mass gap between branches and that subcritical configurations near the critical point form black holes with an apparent horizon mass that follows a power law of the form M(AH)-M(g)∝(p(c)-p)^(ξ), where M(g) is the mass gap and the exponent ξ≃0.7 appears to be universal. PMID:26871317
Simulation of black hole collisions in asymptotically Anti-de Sitter spacetimes.
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. PMID:25768753
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.
Conserved charges for gravity with locally anti-de sitter asymptotics
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. PMID:11017591
New Features of Gravitational Collapse in Anti-de Sitter Spacetimes
NASA Astrophysics Data System (ADS)
Santos-Oliván, Daniel; Sopuerta, Carlos F.
2016-01-01
Gravitational collapse of a massless scalar field in spherically symmetric anti-de Sitter (AdS) spacetimes presents a new phenomenology with a series of critical points whose dynamics is discretely self-similar as in the asymptotically flat case. Each critical point is the limit of a branch of scalar field configurations that have bounced off the AdS boundary a fixed number of times before forming an apparent horizon. We present results from a numerical study that focus on the interfaces between branches. We find that there is a mass gap between branches and that subcritical configurations near the critical point form black holes with an apparent horizon mass that follows a power law of the form MAH-Mg∝(pc-p )ξ, where Mg is the mass gap and the exponent ξ ≃0.7 appears to be universal.
Quantum groups, roots of unity and particles on quantized Anti-de Sitter space
Steinacker, H
1997-05-23
Quantum groups in general and the quantum Anti-de Sitter group U{sub q}(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 {ge} 1, {open_quotes}naive{close_quotes} representations are unitarizable only after factoring out a subspace of {open_quotes}pure gauges{close_quotes}, 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 U{sub q}(g), which plays the role of a BRST operator in the case of U{sub q}(so(2,3)) at roots of unity, for any spin {ge} 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 {open_quotes}truncated{close_quotes} tensor product as well as many-particle representations.
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.
NASA Astrophysics Data System (ADS)
Vasudevan, Muraari; Stevens, Kory A.
2005-12-01
We study the Hamilton-Jacobi and massive Klein-Gordon equations in the general Kerr-(Anti) de Sitter black hole background in all dimensions. Complete separation of both equations is carried out in cases when there are two sets of equal black hole rotation parameters. We analyze explicitly the symmetry properties of these backgrounds that allow for this Liouville integrability and construct a nontrivial irreducible Killing tensor associated with the enlarged symmetry group which permits separation. We also derive first-order equations of motion for particles in these backgrounds and examine some of their properties. This work greatly generalizes previously known results for both the Myers-Perry metrics, and the Kerr-(Anti) de Sitter metrics in higher dimensions.
Gibbons, G. W.; Perry, M. J.; Pope, C. N.
2006-10-15
We reformulate the Bekenstein bound as the requirement of positivity of the Helmholtz free energy at the minimum value of the function L=E-S/(2{pi}R), where R is some measure of the size of the system. The minimum of L occurs at the temperature T=1/(2{pi}R). In the case of n-dimensional anti-de Sitter spacetime, the rather poorly defined size R acquires a precise definition in terms of the AdS radius l, with R=l/(n-2). We previously found that the Bekenstein bound holds for all known black holes in AdS. However, in this paper we show that the Bekenstein bound is not generally valid for free quantum fields in AdS, even if one includes the Casimir energy. Some other aspects of thermodynamics in anti-de Sitter spacetime are briefly touched upon.
NASA Astrophysics Data System (ADS)
Lin, Kai; Yang, ShuZheng
2009-04-01
The 1/2 spin fermions tunneling at the horizon of n-dimensional Kerr-Anti-de Sitter black hole with one rotational parameter is researched via semi-classical approximation method, and the Hawking temperature and fermions tunneling rate are obtained in this Letter. Using a new method, the semi-classical Hamilton-Jacobi equation is gotten from the Dirac equation in this Letter, and the work makes several quantum tunneling theories more harmonious.
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.
Conserved quantities and dual turbulent cascades in Anti-de Sitter spacetime
NASA Astrophysics Data System (ADS)
Green, Stephen; Buchel, Alex; Lehner, Luis; Liebling, Steven
2015-04-01
We consider the dynamics of a spherically symmetric massless scalar field coupled to general relativity in Anti-de Sitter spacetime in the small-amplitude limit. Within the context of our previously developed two time framework (TTF) to study the leading self-gravitating effects, we demonstrate the existence of two new conserved quantities in addition to the known total energy E of the modes: The particle number N and Hamiltonian H of our TTF system. H represents the next-order contribution after E to the total ADM mass M. Simultaneous conservation of E and N implies that weak turbulent processes undergo dual cascades (direct cascade of E and inverse cascade of N or vice versa). This partially explains the observed dynamics of 2-mode initial data. In addition, conservation of E and N limits the region of phase space that can be explored within the TTF approximation and in particular rules out equipartion of energy among the modes for general initial data. Finally, we discuss possible effects of conservation of N and E on late time dynamics.
Conserved quantities and dual turbulent cascades in anti-de Sitter spacetime
NASA Astrophysics Data System (ADS)
Buchel, Alex; Green, Stephen R.; Lehner, Luis; Liebling, Steven L.
2015-03-01
We consider the dynamics of a spherically symmetric massless scalar field coupled to general relativity in anti-de Sitter spacetime in the small-amplitude limit. Within the context of our previously developed two time framework (TTF) to study the leading self-gravitating effects, we demonstrate the existence of two new conserved quantities in addition to the known total energy E of the modes: The particle number N and Hamiltonian H of our TTF system. Simultaneous conservation of E and N implies that weakly turbulent processes undergo dual cascades (direct cascade of E and inverse cascade of N or vice versa). This partially explains the observed dynamics of 2-mode initial data. In addition, conservation of E and N limits the region of phase space that can be explored within the TTF approximation and, in particular, rules out equipartition of energy among the modes for general initial data. Finally, we discuss the possible effects of conservation of N and E on late time dynamics.
Precise relativistic orbits in Kerr and Kerr (anti) de Sitter spacetimes
NASA Astrophysics Data System (ADS)
Kraniotis, G. V.
2004-10-01
The timelike geodesic equations resulting from the Kerr gravitational metric element are derived and solved exactly including the contribution from the cosmological constant. The geodesic equations are derived, by solving the Hamilton Jacobi partial differential equation by separation of variables. The solutions can be applied in the investigation of the motion of a test particle in the Kerr and Kerr (anti) de Sitter gravitational fields. In particular, we apply the exact solutions of the timelike geodesics: (i) to the precise calculation of dragging (Lense Thirring effect) of a satellite's spherical polar orbit in the gravitational field of Earth assuming Kerr geometry; (ii) assuming the galactic centre is a rotating black hole we calculate the precise dragging of a stellar polar orbit around the galactic centre for various values of the Kerr parameter including those supported by recent observations. The exact solution of non-spherical geodesics in Kerr geometry is obtained by using the transformation theory of elliptic functions. The exact solution of spherical polar geodesics with a nonzero cosmological constant can be expressed in terms of Abelian modular theta functions that solve the corresponding Jacobi's inversion problem.
Scalar hair on the black hole in asymptotically anti--de Sitter spacetime
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.
Globally regular instability of 3-dimensional anti-de Sitter spacetime.
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. PMID:23931347
Quasinormal modes of (anti-)de Sitter black holes in the 1 /D expansion
NASA Astrophysics Data System (ADS)
Emparan, Roberto; Suzuki, Ryotaku; Tanabe, Kentaro
2015-04-01
We use the inverse-dimensional expansion to compute analytically the frequencies of a set of quasinormal modes of static black holes of Einstein-(Anti-)de Sitter gravity, including the cases of spherical, planar or hyperbolic horizons. The modes we study are decoupled modes localized in the near-horizon region, which are the ones that capture physics peculiar to each black hole (such as their instabilities), and which in large black holes contain hydrodynamic behavior. Our results also give the unstable Gregory-Laflamme frequencies of Ricci-flat black branes to two orders higher in 1 /D than previous calculations. We discuss the limits on the accuracy of these results due to the asymptotic but not convergent character of the 1 /D expansion, which is due to the violation of the decoupling condition at finite D. Finally, we compare the frequencies for AdS black branes to calculations in the hydrodynamic expansion in powers of the momentum k. Our results extend up to k 9 for the sound mode and to k 8 for the shear mode.
Spherical and planar three-dimensional anti-de Sitter black holes
NASA Astrophysics Data System (ADS)
Zanchin, Vilson T.; Miranda, Alex S.
2004-02-01
The technique of dimensional reduction was used in a recent paper (Zanchin V T, Kleber A and Lemos J P S 2002 Phys. Rev. D 66 064022) where a three-dimensional (3D) Einstein Maxwell dilaton theory was built from the usual four-dimensional (4D) Einstein Maxwell Hilbert action for general relativity. Starting from a class of 4D toroidal black holes in asymptotically anti-de Sitter (AdS) spacetimes several 3D black holes were obtained and studied in such a context. In the present work we choose a particular case of the 3D action which presents Maxwell field, dilaton field and an extra scalar field, besides gravity field and a negative cosmological constant, and obtain new 3D static black hole solutions whose horizons may have spherical or planar topology. We show that there is a 3D static spherically symmetric solution analogous to the 4D Reissner Nordström AdS black hole, and obtain other new 3D black holes with planar topology. From the static spherical solutions, new rotating 3D black holes are also obtained and analysed in some detail.
NASA Astrophysics Data System (ADS)
Peng, Jun-Jin; Wu, Shuang-Qing
2008-03-01
Motivated by the success of the recently proposed method of anomaly cancellation to derive Hawking fluxes from black hole horizons of spacetimes in various dimensions, we have further extended the covariant anomaly cancellation method shortly simplified by Banerjee and Kulkarni to explore the Hawking radiation of the (3 + 1)-dimensional charged rotating black strings and their higher dimensional extensions in anti-de Sitter spacetimes, whose horizons are not spherical but can be toroidal, cylindrical or planar, according to their global identifications. It should be emphasized that our analysis presented here is very general in the sense that the determinant of the reduced (1 + 1)-dimensional effective metric from these black strings need not be equal to one (√{ - g } ≠ 1). Our results indicate that the gauge and energy-momentum fluxes needed to cancel the (1 + 1)-dimensional covariant gauge and gravitational anomalies are compatible with the Hawking fluxes. Besides, thermodynamics of these black strings are studied in the case of a variable cosmological constant.
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.
Randall-Sundrum membrane model with 7D anti-de Sitter space
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.
Miranda, Alex S.; Zanchin, Vilson T.
2006-03-15
We study in detail the quasinormal modes of linear gravitational perturbations of plane-symmetric anti-de Sitter black holes. The wave equations are obtained by means of the Newman-Penrose formalism and the Chandrasekhar transformation theory. We show that oscillatory modes decay exponentially with time such that these black holes are stable against gravitational perturbations. Our numerical results show that in the large (small) black hole regime the frequencies of the ordinary quasinormal modes are proportional to the horizon radius r{sub +} (wave number k). The frequency of the purely damped mode is very close to the algebraically special frequency in the small horizon limit, and goes as ik{sup 2}/3r{sub +} in the opposite limit. This result is confirmed by an analytical method based on the power series expansion of the frequency in terms of the horizon radius. The same procedure applied to the Schwarzschild anti-de Sitter spacetime proves that the purely damped frequency goes as i(l-1)(l+2)/3r{sub +}, where l is the quantum number characterizing the angular distribution. Finally, we study the limit of high overtones and find that the frequencies become evenly spaced in this regime. The spacing of the frequency per unit horizon radius seems to be a universal quantity, in the sense that it is independent of the wave number, perturbation parity, and black hole size.
Test of the Anti-de Sitter-Space/Conformal-Field-Theory Correspondence Using High-Spin Operators
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.
Quasinormal modes of black holes in anti-de Sitter space: A numerical study of the eikonal limit
Morgan, Jaqueline; Zanchin, Vilson T.; Cardoso, Vitor; Miranda, Alex S.; Molina, C.
2009-07-15
Using series solutions and time-domain evolutions, we probe the eikonal limit of the gravitational and scalar-field quasinormal modes of large black holes and black branes in anti-de Sitter backgrounds. These results are particularly relevant for the AdS/CFT correspondence, since the eikonal regime is characterized by the existence of long-lived modes which (presumably) dominate the decay time scale of the perturbations. We confirm all the main qualitative features of these slowly damped modes as predicted by Festuccia and Liu [G. Festuccia and H. Liu, arXiv:0811.1033.] for the scalar-field (tensor-type gravitational) fluctuations. However, quantitatively we find dimensional-dependent correction factors. We also investigate the dependence of the quasinormal mode frequencies on the horizon radius of the black hole (brane) and the angular momentum (wave number) of vector- and scalar-type gravitational perturbations.
Quasilocal thermodynamics of Kerr and Kerr--anti-de Sitter spacetimes and the AdS/CFT correspondence
Dehghani, M. H.; Mann, R. B.
2001-08-15
We consider the quasilocal thermodynamics of rotating black holes in asymptotically flat and asymptotically anti--de Sitter (AdS) spacetimes. Using the minimal number of intrinsic boundary counterterms inspired by the AdS/conformal field theory correspondence, we find that we are able to carry out an analysis of the thermodynamics of these black holes for virtually all possible values of the rotation parameter and cosmological constant that leave the quasilocal boundary well defined, going well beyond what is possible with background subtraction methods. Specifically, we compute the quasilocal energy E and angular momentum J for arbitrary values of the rotation, mass, and cosmological constant parameters for the (3+1)-dimensional Kerr, Kerr-AdS black holes, and (2+1)-dimensional Banados-Teitelboim-Zannelli (BTZ) black hole. We perform a quasilocal stability analysis and find phase behavior that is commensurate with previous analyses carried out at infinity.
NASA Astrophysics Data System (ADS)
Santos-Oliván, Daniel; Sopuerta, Carlos F.
2016-05-01
We present a new hybrid Cauchy-characteristic evolution scheme that is particularly suited to study gravitational collapse in spherically symmetric asymptotically (global) anti-de Sitter (AdS) spacetimes. The Cauchy evolution allows us to track the scalar field through the different round trips to the AdS boundary, while the characteristic method can bring us very close to the point of formation of an apparent horizon. We describe all the details of the method, including the transition between the two evolution schemes and the details of the numerical implementation for the case of massless scalar fields. We use this scheme to provide more numerical evidence for a recent conjecture on the power law scaling of the apparent horizon mass resulting from the collapse of subcritical configurations. We also compute the critical exponents and echoing periods for a number of critical points and confirm the expectation that their values should be the same as in the asymptotically flat case.
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.
NASA Astrophysics Data System (ADS)
Li, Ran; Zhao, Jun-Kun
2016-04-01
We investigate the massive vector particles' Hawking radiation from the neutral rotating Anti-de Sitter (AdS) black holes in conformal gravity by using the tunneling method. It is well known that the dynamics of massive vector particles are governed by the Proca field equation. Applying WKB approximation to the Proca equation, the tunneling probabilities and radiation spectrums of the emitted particles are derived. Hawking temperature of the neutral rotating AdS black holes in conformal gravity is recovered, which is consistent with the previous result in the literature. Supported by the National Natural Science Foundation of China under Grant No. 11205048, and the Foundation for Young Key Teacher of Henan Normal University
NASA Astrophysics Data System (ADS)
Rahman, M. Atiqur; Hossain, M. Ilias
2013-06-01
The massive particles tunneling method has been used to investigate the Hawking non-thermal and purely thermal radiations of Schwarzschild Anti-de Sitter (SAdS) black hole. Considering the spacetime background to be dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has been derived from Hamilton-Jacobi equation. Using the conservation laws of energy and angular momentum we have showed that the non-thermal and purely thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The result obtained for SAdS black hole is also in accordance with Parikh and Wilczek's opinion and gives a correction to the Hawking radiation of SAdS black hole.
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.
NASA Astrophysics Data System (ADS)
Wu, Shuang-Qing
2009-03-01
It is shown that the Dirac equation is separable by variables in a five-dimensional rotating Kerr (anti-)de Sitter black hole with two independent angular momenta. A first-order symmetry operator that commutes with the Dirac operator is constructed in terms of a rank-3 Killing Yano tensor whose square is a second-order symmetric Stäckel Killing tensor admitted by the five-dimensional Kerr (anti-)de Sitter spacetime. We highlight the construction procedure of such a symmetry operator. In addition, the first law of black hole thermodynamics has been extended to the case that the cosmological constant can be viewed as a thermodynamical variable.
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.
NASA Astrophysics Data System (ADS)
Wang, Mengjie; Herdeiro, Carlos
2016-03-01
Scalar and gravitational perturbations on Kerr-anti-de Sitter (Kerr-AdS) black holes have been addressed in the literature and have been shown to exhibit a rich phenomenology. In this paper, we complete the analysis of bosonic fields on this background by studying Maxwell perturbations, focusing on superradiant instabilities and vector clouds. For this purpose, we solve the Teukolsky equations numerically, imposing the boundary conditions we have proposed in [1] for the radial Teukolsky equation. As found therein, two Robin boundary conditions can be imposed for Maxwell fields on Kerr-AdS black holes, one of which produces a new set of quasinormal modes even for Schwarzschild-AdS black holes. Here, we show these different boundary conditions produce two different sets of superradiant modes. Interestingly, the "new modes" may be unstable in a larger parameter space. We then study stationary Maxwell clouds that exist at the threshold of the superradiant instability, with the two Robin boundary conditions. These clouds, obtained at the linear level, indicate the existence of a new family of black hole solutions at the nonlinear level, within the Einstein-Maxwell-AdS system, branching off from the Kerr-Newman-AdS family. As a comparison with the Maxwell clouds, scalar clouds on Kerr-AdS black holes are also studied, and it is shown there are Kerr-AdS black holes that are stable against scalar, but not vector, modes with the same "quantum numbers".
Stability of Gauss-Bonnet black holes in anti-de Sitter space-time against scalar field condensation
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.
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.
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
Uchikata, Nami; Yoshida, Shijun
2011-03-15
We investigate quasinormal modes of a massless charged scalar field on a small Reissner-Nordstroem-anti-de Sitter (RN-AdS) black hole both with analytical and numerical approaches. In the analytical approach, by using the small black hole approximation (r{sub +}<
Berenstein, David; Correa, Diego H.; Vazquez, Samuel E.
2005-11-04
We study an XXX open spin chain with variable number of sites, where the variability is introduced only at the boundaries. This model arises naturally in the study of giant gravitons in the anti-de Sitter-space/conformal field-theory correspondence. We show how to quantize the spin chain by mapping its states to a bosonic lattice of finite length with sources and sinks of particles at the boundaries. Using coherent states, we show how the Hamiltonian for the bosonic lattice gives the correct description of semiclassical open strings ending on giant gravitons.
NASA Astrophysics Data System (ADS)
Mehdipour, S. Hamid
2014-09-01
We try to study the thermodynamical features of a non-commutative inspired Schwarzschild-anti-de Sitter black hole in the context of the entropic gravity model, particularly for the model that is employed in a broad range of scales, from the short distances to the large distances. At small length scales, the Newtonian force fails because one finds a linear relation between the entropic force and the distance. In addition, there are some deviations from the standard Newtonian gravity at large length scales.
Noronha, Jorge; Gyulassy, Miklos; Torrieri, Giorgio
2009-03-13
We show that far zone Mach and diffusion wake 'holograms' produced by supersonic strings in anti-de Sitter space/conformal field theory (AdS/CFT) correspondence do not lead to observable conical angular correlations in the strict N{sub c}{yields}{infinity} supergravity limit if Cooper-Frye hadronization is assumed. However, a special nonequilibrium 'neck' zone near the jet is shown to produce an apparent sonic boom azimuthal angle distribution that is roughly independent of the heavy quark's velocity. Our results indicate that a measurement of the dependence of the away-side correlations on the velocity of associated identified heavy quark jets at the BNL Relativistic Heavy Ion Collider and CERN LHC will provide a direct test of the nonperturbative dynamics involved in the coupling between jets and the strongly coupled quark-gluon plasma implied by AdS/CFT correspondence.
Noronha, Jorge; Gyulassy, Miklos; Torrieri, Giorgio
2009-03-13
We show that far zone Mach and diffusion wake "holograms" produced by supersonic strings in anti-de Sitter space/conformal field theory (AdS/CFT) correspondence do not lead to observable conical angular correlations in the strict N_{c}-->infinity supergravity limit if Cooper-Frye hadronization is assumed. However, a special nonequilibrium "neck" zone near the jet is shown to produce an apparent sonic boom azimuthal angle distribution that is roughly independent of the heavy quark's velocity. Our results indicate that a measurement of the dependence of the away-side correlations on the velocity of associated identified heavy quark jets at the BNL Relativistic Heavy Ion Collider and CERN LHC will provide a direct test of the nonperturbative dynamics involved in the coupling between jets and the strongly coupled quark-gluon plasma implied by AdS/CFT correspondence. PMID:19392107
NASA Astrophysics Data System (ADS)
Ilias Hossain, M.; Atiqur Rahman, M.
2013-09-01
We have investigated Hawking non-thermal and purely thermal Radiations of Reissner Nordström anti-de Sitter (RNAdS) black hole by massive particles tunneling method. The spacetime background has taken as dynamical, incorporate the self-gravitation effect of the emitted particles the imaginary part of the action has derived from Hamilton-Jacobi equation. We have supposed that energy and angular momentum are conserved and have shown that the non-thermal and thermal tunneling rates are related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results for RNAdS black hole is also in the same manner with Parikh and Wilczek's opinion and explored the new result for Hawking radiation of RNAdS black hole.
NASA Astrophysics Data System (ADS)
Li, Ran; Zhang, Hongbao; Zhao, Junkun
2016-07-01
Reissner-Nordström Anti-de Sitter (RNAdS) black holes are unstable against the charged scalar field perturbations due to the well-known superradiance phenomenon. We present the time domain analysis of charged scalar field perturbations in the RNAdS black hole background in general dimensions. We show that the instabilities of charged scalar field can be explicitly illustrated from the time profiles of evolving scalar field. By using the Prony method to fit the time evolution data, we confirm the mode that dominates the long time behavior of scalar field is in accordance with the quasinormal mode from the frequency domain analysis. The superradiance origin of the instability can also be demonstrated by comparing the real part of the dominant mode with the superradiant condition of charged scalar field. It is shown that all the unstable modes are superradiant, which is consistent with the analytical result in the frequency domain analysis. Furthermore, we also confirm there exists the rapid exponential growing modes in the RNAdS case, which makes the RNAdS black hole a good test ground to investigate the nonlinear evolution of superradiant instability.
Dias, Goncalo A. S.; Lemos, Jose P. S.
2009-02-15
The Hamiltonian thermodynamics formalism is applied to the general d-dimensional Reissner-Nordstroem-anti-de Sitter black hole with spherical, planar, and hyperbolic horizon topology. After writing its action and performing a Legendre transformation, surface terms are added in order to guarantee a well-defined variational principle with which to obtain sensible equations of motion, and also to allow later on the thermodynamical analysis. Then a Kuchar canonical transformation is done, which changes from the metric canonical coordinates to the physical parameters coordinates. Again, a well-defined variational principle is guaranteed through boundary terms. These terms influence the falloff conditions of the variables and at the same time the form of the new Lagrange multipliers. Reduction to the true degrees of freedom is performed, which are the conserved mass and charge of the black hole. Upon quantization a Lorentzian partition function Z is written for the grand canonical ensemble, where the temperature T and the electric potential {phi} are fixed at infinity. After imposing Euclidean boundary conditions on the partition function, the respective effective action I{sub *}, and thus the thermodynamical partition function, is determined for any dimension d and topology k. This is a quite general action. Several previous results can be then condensed in our single general formula for the effective action I{sub *}. Phase transitions are studied for the spherical case, and it is shown that all the other topologies have no phase transitions. A parallel with the Bose-Einstein condensation can be established. Finally, the expected values of energy, charge, and entropy are determined for the black hole solution.
DeSitter entropy, quantum entanglement and ADS/CFT
NASA Astrophysics Data System (ADS)
Hawking, Stephen; Maldacena, Juan; Strominger, Andrew
2001-05-01
A de Sitter brane-world bounding regions of anti-de Sitter space has a macroscopic entropy given by one-quarter the area of the observer horizon. A proposed variant of the AdS/CFT correspondence gives a dual description of this cosmology as conformal field theory coupled to gravity in de Sitter space. In the case of two-dimensional de Sitter space this provides a microscopic derivation of the entropy, including the one-quarter, as quantum entanglement of the conformal field theory across the horizon.
Conformally covariant quantization of the Maxwell field in de Sitter space
NASA Astrophysics Data System (ADS)
Faci, S.; Huguet, E.; Queva, J.; Renaud, J.
2009-12-01
In this article, we quantize the Maxwell (“massless spin one”) de Sitter field in a conformally invariant gauge. This quantization is invariant under the SO0(2,4) group and consequently under the de Sitter group. We obtain a new de Sitter-invariant two-point function which is very simple. Our method relies on the one hand on a geometrical point of view which uses the realization of Minkowski, de Sitter and anti-de Sitter spaces as intersections of the null cone in R6 and a moving plane, and on the other hand on a canonical quantization scheme of the Gupta-Bleuler type.
Anti-de Sitter universe dynamics in loop quantum cosmology
Bentivegna, Eloisa; Pawlowski, Tomasz
2008-06-15
A model for a flat isotropic universe with a negative cosmological constant {lambda} and a massless scalar field as sole matter content is studied within the framework of loop quantum cosmology. By application of the methods introduced for the model with {lambda}=0, the physical Hilbert space and the set of Dirac observables are constructed. As in that case, the scalar field plays here the role of an emergent time. The properties of the system are found to be similar to those of the k=1 Friedmann-Robertson-Walker (FRW) model: for small energy densities, the quantum dynamics reproduces the classical one, whereas, due to modifications at near-Planckian densities, the big bang and big crunch singularities are replaced by a quantum bounce connecting deterministically the large semiclassical epochs. Thus in loop quantum cosmology the evolution is qualitatively cyclic.
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.
Anti-de Sitter universe dynamics in loop quantum cosmology
NASA Astrophysics Data System (ADS)
Bentivegna, Eloisa; Pawlowski, Tomasz
2008-06-01
A model for a flat isotropic universe with a negative cosmological constant Λ and a massless scalar field as sole matter content is studied within the framework of loop quantum cosmology. By application of the methods introduced for the model with Λ=0, the physical Hilbert space and the set of Dirac observables are constructed. As in that case, the scalar field plays here the role of an emergent time. The properties of the system are found to be similar to those of the k=1 Friedmann-Robertson-Walker (FRW) model: for small energy densities, the quantum dynamics reproduces the classical one, whereas, due to modifications at near-Planckian densities, the big bang and big crunch singularities are replaced by a quantum bounce connecting deterministically the large semiclassical epochs. Thus in loop quantum cosmology the evolution is qualitatively cyclic.
Covariant quantization of the Maxwell field in de Sitter space from SO0(2,4)-invariance
NASA Astrophysics Data System (ADS)
Huguet, E.; Faci, S.; Queva, J.; Renaud, J.
2011-03-01
We present a SO0(2,4)-invariant quantization of the free electromagnetic field in de Sitter space. Precisely, we quantize the Maxwell ("massless spin one") de Sitter field in a conformally invariant gauge. This result is obtained thanks to a canonical quantization scheme of the Gupta-Bleuler type and to a geometrical formalism in which the Minkowski, de Sitter and anti-de Sitter spaces are realized as intersections of the five dimensional null cone of ℝ6 and a moving hyperplane. We obtain a new and simple de Sitter invariant two-point function.
Constraints on Meta-stable de Sitter Flux Vacua
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.
Extremal surfaces in de Sitter spacetime
NASA Astrophysics Data System (ADS)
Narayan, K.
2015-06-01
We study extremal surfaces in de Sitter space in the Poincare slicing in the upper patch, anchored on spatial subregions at the future boundary I+, restricted to constant boundary Euclidean time slices (focusing on strip subregions). We find real extremal surfaces of minimal area as the boundaries of past light-cone wedges of the subregions in question: these are null surfaces with vanishing area. We also find complex extremal surfaces as complex extrema of the area functional, and the area is not always real valued. In dS4 the area is real. The area has structural resemblance with entanglement entropy in a dual conformal field theory. There are parallels with analytic continuation from the Ryu-Takayanagi expressions for holographic entanglement entropy in anti-de Sitter. We also discuss extremal surfaces in the de Sitter (dS) black brane and the de Sitter "bluewall" studied previously. The dS4 black brane complex surfaces exhibit a real finite cutoff-independent extensive piece. In the bluewall geometry, there are real surfaces that go from one asymptotic universe to the other through the Cauchy horizons.
Instability of the de Sitter Reissner–Nordstrom black hole in the 1/D expansion
NASA Astrophysics Data System (ADS)
Tanabe, Kentaro
2016-06-01
We study the large D effective theory for D dimensional charged (Anti) de Sitter black holes. Then we show that the de Sitter Reissner–Nordstrom black hole becomes unstable against gravitational perturbations at larger charge than a critical charge in a higher dimension. Furthermore, we find that there is a nontrivial zero-mode static perturbation at the critical charge. The existence of static perturbations suggests the appearance of non-spherical symmetric solution branches of static charged de Sitter black holes. This expectation is confirmed by constructing the non-spherical symmetric static solutions of large D effective equations.
Classical and Quantum Symmetries of de Sitter Space
NASA Astrophysics Data System (ADS)
Anninos, Dionysios Theodoros
2011-10-01
De Sitter space is the maximally symmetric cosmology satisfying Einstein's equations with a positive cosmological constant. It has played a crucial role in the theory of inflationary cosmology. Recent astronomical observations indicate our universe is entering a new asymptotically de Sitter phase, with a mysteriously small value for the cosmological constant. We study several aspects of de Sitter and de Sitter-esque geometries in three and four spacetime dimensions. Particularly, we discuss the asymptotic symmetry group (ASG) of four-dimensional de Sitter space at future infinity, I+ , in Einstein gravity with positive cosmological constant. We find, very much unlike its anti-de Sitter cousin, an infinite dimensional group consisting of the three-dimensional diffeomorphisms acting on I+ . We then move on to rotating black holes in de Sitter space and focus on a limit where the black hole and cosmological horizons coincide. We compute the ASG of the near (cosmological) horizon geometry, the rotating Nariai geometry, which has its own future boundary I+RN and find a Virasoro algebra. This is suggestive of a holographically dual interpretation in terms of a two-dimensional CFT. Scalar waves in the rotating Nariai geometry are studied to provide further evidence for the proposal. Finally, we find toy models of the rotating Nariai geometry in three-dimensional theories of gravity with a gravitational Chern-Simons term and further explore the possibility of a holographic duality. Interestingly, we find a de Sitter like vacuum, warped dS3, whose smooth quotients contain both a cosmological as well as an internal event horizon. In contrast, quotients of Lorentzian dS3 always contain conical singularities.
Decay of magnetic fields in de Sitter and FRW universes
NASA Astrophysics Data System (ADS)
Garcia de Andrade, L. C.; Ferrández, A.
2011-11-01
Magnetic curvature effects, investigated by Barrow and Tsagas (Phys. Rev. D 77, 107302 (2008)), as a mechanism for magnetic field decay in open Friedmann universes ( Λ < 0), are applied to dynamo geometric Ricci flows in 3D curved substrate in laboratory. By simple derivation, a covariant three-dimensional magnetic self-induction equation is obtained. The presence of these curvature effects indicates that de Sitter cosmological constant ( Λ ≥ 0 leads to enhancement in the fast kinematic dynamo action which induces a stretching in plasma flows. From the magnetic growth rate, the strong shear case implies an anti-de Sitter case ( Λ < 0) where BT magnetic decaying fields are possible. For weak shear, fast dynamos are possible. The self-induced equation in Ricci flows is similar to the equation derived by BT in the (3 + 1)-spacetime continuum. Lyapunov-de Sitter metric is obtained from Ricci flow eigenvalue problem. In the de Sitter analogue there is a decay rate of γ ≈ - Λ ≈ -10-35 s-2 from the corresponding cosmological constant Λ. This shows that, even in the dynamo case, the magnetic field growth is slower than de Sitter inflation, which renders strongly support to BT result.
Black hole solutions for scale-dependent couplings: the de Sitter and the Reissner-Nordström case
NASA Astrophysics Data System (ADS)
Koch, Benjamin; Rioseco, Paola
2016-02-01
Allowing for scale dependence of the gravitational couplings leads to a generalization of the corresponding field equations. In this work, these equations are solved for the Einstein-Hilbert and the Einstein-Maxwell case, leading to generalizations of the (Anti)-de Sitter and the Reissner-Nordström black holes. These solutions are discussed and compared to their classical counterparts.
A note on Schwarzschild-de Sitter black holes in mimetic F(R) gravity
NASA Astrophysics Data System (ADS)
Oikonomou, V. K.
2016-05-01
In this paper, we investigate the conditions under which a Schwarzschild-de Sitter black hole spacetime is a solution of the mimetic F(R) gravity with Lagrange multiplier and potential. As we demonstrate, the resulting mimetic F(R) gravity is a slight modification of the ordinary F(R) gravity case, however the resulting perturbation equations are not in all cases identical to the ordinary F(R) gravity case. In the latter case, the perturbation equations are identical to the ones corresponding to the Reissner-Nordström anti-de Sitter black hole.
'Micromanaging de Sitter holography'
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
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
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.
Asymptotically warped anti-de Sitter spacetimes in topologically massive gravity
NASA Astrophysics Data System (ADS)
Henneaux, Marc; Martínez, Cristián; Troncoso, Ricardo
2011-12-01
Asymptotically warped AdS spacetimes in topologically massive gravity with negative cosmological constant are considered in the case of spacelike stretched warping, where black holes have been shown to exist. We provide a set of asymptotic conditions that accommodate solutions in which the local degree of freedom (the “massive graviton”) is switched on. An exact solution with this property is explicitly exhibited and possesses a slower falloff than the warped AdS black hole. The boundary conditions are invariant under the semidirect product of the Virasoro algebra with a u(1) current algebra. We show that the canonical generators are integrable and finite. When the graviton is not excited, our analysis is compared and contrasted with earlier results obtained through the covariant approach to conserved charges. In particular, we find agreement with the conserved charges of the warped AdS black holes as well as with the central charges in the algebra.
One-loop effective action and Schwinger effect in (anti-) de Sitter space
NASA Astrophysics Data System (ADS)
Cai, Rong-Gen; Kim, Sang Pyo
2014-09-01
We study the Schwinger mechanism by a uniform electric field in dS2 and AdS2 and the curvature effect on the Schwinger effect, and further propose a thermal interpretation of the Schwinger formula in terms of the Gibbons-Hawking temperature and the Unruh temperature for an accelerating charge in dS2 and an analogous expression in AdS2. The exact one-loop effective action is found in the proper-time integral in each space, which is determined by the effective mass, the Maxwell scalar, and the scalar curvature, and whose pole structure gives the imaginary part of the effective action and the exact pair-production rate. The exact pair-production rate is also given the thermal interpretation.
Conformally Coupled Scalars, Instantons, and Vacuum Instability in 4D Anti-de Sitter Space
Haro, Sebastian de; Papadimitriou, Ioannis; Petkou, Anastasios C.
2007-06-08
We show that a scalar field conformally coupled to AdS gravity in four dimensions with a quartic self-interaction can be embedded into M theory. The holographic effective potential is exactly calculated, allowing us to study nonperturbatively the stability of AdS{sub 4} in the presence of the conformally coupled scalar. It is shown that there exists a one-parameter family of conformal scalar boundary conditions for which the boundary theory has an unstable vacuum. In this case, the bulk theory has instanton solutions that mediate the decay of the AdS{sub 4} space. These results match nicely with the vacuum structure and the existence of instantons in an effective three-dimensional boundary model.
Quasinormal frequencies of asymptotically anti-de Sitter black holes in two dimensions
NASA Astrophysics Data System (ADS)
Cordero, R.; López-Ortega, A.; Vega-Acevedo, I.
2012-04-01
We calculate exactly the quasinormal frequencies of Klein-Gordon and Dirac test fields propagating in 2D uncharged Achucarro-Ortiz black hole. For both test fields we study whether the quasinormal frequencies are well defined in the massless limit. We use their values to discuss the classical stability of the quasinormal modes in uncharged Achucarro-Ortiz black hole and to check the recently proposed Time Times Temperature bound. Furthermore we extend some of these results to the charged Achucarro-Ortiz black hole.
Anti-de Sitter-space/conformal-field-theory correspondence and large-N volume independence
Poppitz, Erich; Uensal, Mithat
2010-09-15
We study the Eguchi-Kawai reduction in the strong-coupling domain of gauge theories via the gravity dual of N=4 super-Yang-Mills on R{sup 3}xS{sup 1}. We show that D-branes geometrize volume independence in the center-symmetric vacuum and give supergravity predictions for the range of validity of reduced large-N models at strong coupling.
On a canonical quantization of 3D Anti de Sitter pure gravity
NASA Astrophysics Data System (ADS)
Kim, Jihun; Porrati, Massimo
2015-10-01
We perform a canonical quantization of pure gravity on AdS 3 using as a technical tool its equivalence at the classical level with a Chern-Simons theory with gauge group SL(2,{R})× SL(2,{R}) . We first quantize the theory canonically on an asymptotically AdS space -which is topologically the real line times a Riemann surface with one connected boundary. Using the "constrain first" approach we reduce canonical quantization to quantization of orbits of the Virasoro group and Kähler quantization of Teichmüller space. After explicitly computing the Kähler form for the torus with one boundary component and after extending that result to higher genus, we recover known results, such as that wave functions of SL(2,{R}) Chern-Simons theory are conformal blocks. We find new restrictions on the Hilbert space of pure gravity by imposing invariance under large diffeomorphisms and normalizability of the wave function. The Hilbert space of pure gravity is shown to be the target space of Conformal Field Theories with continuous spectrum and a lower bound on operator dimensions. A projection defined by topology changing amplitudes in Euclidean gravity is proposed. It defines an invariant subspace that allows for a dual interpretation in terms of a Liouville CFT. Problems and features of the CFT dual are assessed and a new definition of the Hilbert space, exempt from those problems, is proposed in the case of highly-curved AdS 3.
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.
Infrared surprises in the de Sitter universe
NASA Astrophysics Data System (ADS)
Moschella, Ugo
2016-06-01
We describe a few unexpected features of de Sitter quantum field theory (QFT) that have no Minkowskian counterparts. These phenomena show that even when the cosmological constant is tiny a Minkowskian way of fast thinking about de Sitter can lead to mistakes and that de Sitter QFT is essentially different from standard relativistic (Minkowskian) QFT.
De Sitter brane-world, localization of gravity, and the cosmological constant
NASA Astrophysics Data System (ADS)
Neupane, Ishwaree P.
2011-04-01
Cosmological models with a de Sitter 3-brane embedded in a 5-dimensional de Sitter spacetime (dS5) 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(AdS5). 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) MPl2=M(5)3ℓAdS as well as the relationship MPl2=MPl(4+n)n+2Ln (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, MPl, and MPl(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 MPl and MPl(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 Λb can take either sign (Λb<0, =0, or >0). The D=6 case is rather inconclusive, in which case Λb 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 that remains finite and a normalizable zero-mode graviton wave function.
An evaluation of a sitter reduction program intervention.
Spiva, LeeAnna; Feiner, Therese; Jones, Darcia; Hunter, Donna; Petefish, Jayne; VanBrackle, Lewis
2012-01-01
Hospitals use sitters as an alternative to reduce patient falls. The purpose of the study was to evaluate the effectiveness of a sitter reduction program by examining the differences between sitter use and falls in an acute care hospital. Findings indicate that a significant decrease in sitter use and falls remained constant. Reducing sitter use is possible without significantly increasing fall rates. PMID:22692004
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.
Infrared divergences in de Sitter space
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.
NASA Astrophysics Data System (ADS)
Dadras, Pouria; Firouzjaee, J. T.; Mansouri, Reza
2012-11-01
We propose a special solution of Einstein equations in the general Vaidya form representing a dynamical black hole having horizon cross-sections with toroidal topology. The concrete model enables us to study for the first time dynamical horizons with toroidal topology, its area law, and the question of matter flux inside the horizon, without using a cut-and-paste technology to construct the solution.
Negative mass bubbles in de Sitter spacetime
NASA Astrophysics Data System (ADS)
Mbarek, Saoussen; Paranjape, M. B.
2014-11-01
We study the possibility of the existence of negative mass bubbles within a de Sitter spacetime background with matter content corresponding to a perfect fluid. It is shown that there exist configurations of the perfect fluid that satisfy everywhere the dominant energy condition, the Einstein equations and the equations of hydrostatic equilibrium which asymptotically approach the exact solution of Schwarzschild—de Sitter spacetime with a negative mass.
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.
NASA Astrophysics Data System (ADS)
Nishi, Masato
2016-07-01
We discuss the large mass hierarchy problem in a braneworld model which represents our acceleratively expanding universe. The Randall-Sundrum (RS) model with one extra warped dimension added to a flat four-dimensional space-time cannot describe our expanding universe. Here, we study instead the de Sitter thin brane model. This is described by the same action as that for the RS model, but the four-dimensional space-time on the branes is dS_4. We study the model for both the cases of positive five-dimensional cosmological constant Λ_5 and a negative one. In the positive Λ_5 case, the four-dimensional large hierarchy necessitates a five-dimensional large hierarchy, and we cannot get a natural explanation. On the other hand, in the negative Λ_5 case, the large hierarchy is naturally realized in the five-dimensional theory in the same manner as in the RS model. Moreover, another large hierarchy between the Hubble parameter and the Planck scale is realized by the O(10^2) hierarchy of the five-dimensional quantities. Finally, we find that the lightest mass of the massive Kaluza-Klein modes and the intervals of the mass spectrum are of order 10^2 GeV, which are the same as in the RS case and do not depend on the value of the Hubble parameter.
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.
A natural fuzzyness of de Sitter spacetime
NASA Astrophysics Data System (ADS)
Gazeau, Jean-Pierre; Toppan, Francesco
2010-01-01
A non-commutative structure for de Sitter spacetime is naturally introduced by replacing ('fuzzyfication') the classical variables of the bulk in terms of the dS analogs of the Pauli-Lubanski operators. The dimensionality of the fuzzy variables is determined by a Compton length and the commutative limit is recovered for distances much larger than the Compton distance. The choice of the Compton length determines different scenarios. In scenario I the Compton length is determined by the limiting Minkowski spacetime. A fuzzy dS in scenario I implies a lower bound (of the order of the Hubble mass) for the observed masses of all massive particles (including massive neutrinos) of spin s > 0. In scenario II the Compton length is fixed in the de Sitter spacetime itself and grossly determines the number of finite elements ('pixels' or 'granularity') of a de Sitter spacetime of a given curvature.
Observation assistants: sitter effectiveness and industry measures.
Harding, Andrew D
2010-01-01
Patient safety remains a strategic goal and of societal importance for better health care. Direct observation remains an ineffective and expensive means of providing for patient safety. The nursing quality team found that using assessment tools helped to objectively categorize which patients are at risk. Defining patient volume, actual productive sitter usage, and assessing demand for patients in psychiatric crisis and patients at high risk to fall in the form of average daily census provided an easy-to-translate, familiar unit of measure to compare patient volume to demand and utilization. The sitter utilization case was unable to provide correlation of sitter use to decreased fall rates, elopement, or assault behaviors. Currently, there is no research to suggest the use of constant observation reduces the risk of patient harm related to their risk for falling or harming themselves. PMID:21158254
Remark on massive particle's de Sitter tunneling
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.
Entropic uncertainty relation in de Sitter space
NASA Astrophysics Data System (ADS)
Jia, Lijuan; Tian, Zehua; Jing, Jiliang
2015-02-01
The uncertainty principle restricts our ability to simultaneously predict the measurement outcomes of two incompatible observables of a quantum particle. However, this uncertainty could be reduced and quantified by a new Entropic Uncertainty Relation (EUR). By the open quantum system approach, we explore how the nature of de Sitter space affects the EUR. When the quantum memory A freely falls in the de Sitter space, we demonstrate that the entropic uncertainty acquires an increase resulting from a thermal bath with the Gibbons-Hawking temperature. And for the static case, we find that the temperature coming from both the intrinsic thermal nature of the de Sitter space and the Unruh effect associated with the proper acceleration of A also brings effect on entropic uncertainty, and the higher the temperature, the greater the uncertainty and the quicker the uncertainty reaches the maximal value. And finally the possible mechanism behind this phenomenon is also explored.
NASA Astrophysics Data System (ADS)
Akcay, Sarp; Matzner, Richard A.
2011-04-01
It is now widely accepted that the universe as we understand it is accelerating in expansion and fits the de Sitter model rather well. As such, a realistic assumption of black holes must place them on a de Sitter background and not Minkowski as is typically done in general relativity. The most astrophysically relevant black hole is the uncharged, rotating Kerr solution, a member of the more general Kerr-Newman metrics. A generalization of the rotating Kerr black hole to a solution of the Einstein's equation with a cosmological constant Λ was discovered by Carter (1973 Les Astres Occlus ed B DeWitt and C M DeWitt (New York: Gordon and Breach)). It is typically referred to as the Kerr-de Sitter spacetime. Here, we discuss the horizon structure of this spacetime and its dependence on Λ. We recall that in a Λ > 0 universe, the term 'extremal black hole' refers to a black hole with angular momentum J > M2. We obtain explicit numerical results for the black hole's maximal spin value and get a distribution of admissible Kerr holes in the (Λ, spin) parameter space. We look at the conformal structure of the extended spacetime and the embedding of the 3-geometry of the spatial hypersurfaces. In analogy with Reissner-Nordström-de Sitter spacetime, in particular by considering the Kerr-de Sitter causal structure as a distortion of the Reissner-Nordström-de Sitter one, we show that spatial sections of the extended spacetime are 3-spheres containing two-dimensional topologically spherical sections of the horizons of Kerr holes at the poles. Depending on how a t = constant 3-space is defined, these holes may be seen as black or white holes (four possible combinations).
New instabilities of de Sitter spacetimes
Copsey, Keith; Mann, Robert
2010-04-15
We construct an instanton describing the pair production of non-Kaluza-Klein bubbles of nothing in higher odd-dimensional de Sitter spaces. In addition to showing that higher-dimensional de Sitter spaces have a nonzero probability to become topologically nontrivial, this process provides direct evidence for the association of entropy with cosmological horizons as well as evidence that non-Kaluza-Klein bubbles of nothing are a necessary ingredient in string theory or any other consistent quantum theory of gravity in higher dimensions.
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.
Schwinger effect in de Sitter space
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∼
Matter-coupled de Sitter supergravity
NASA Astrophysics Data System (ADS)
Kallosh, R. E.
2016-05-01
The de Sitter supergravity describes the interaction of supergravity with general chiral and vector multiplets and also one nilpotent chiral multiplet. The extra universal positive term in the potential, generated by the nilpotent multiplet and corresponding to the anti-D3 brane in string theory, is responsible for the de Sitter vacuum stability in these supergravity models. In the flat-space limit, these supergravity models include the Volkov-Akulov model with a nonlinearly realized supersymmetry. We generalize the rules for constructing the pure de Sitter supergravity action to the case of models containing other matter multiplets. We describe a method for deriving the closed-form general supergravity action with a given potential K, superpotential W, and vectormatrix fAB interacting with a nilpotent chiral multiplet. It has the potential V = eK(|F2|+|DW|2-3|W|2), where F is the auxiliary field of the nilpotent multiplet and is necessarily nonzero. The de Sitter vacuums are present under the simple condition that |F2|-3|W|2 > 0. We present an explicit form of the complete action in the unitary gauge.
NASA Astrophysics Data System (ADS)
Cicoli, Michele; Quevedo, Fernando; Valandro, Roberto
2016-03-01
Hidden sector D7-branes with non-zero gauge flux are a generic feature of type IIB compactifications. A non-vanishing Fayet-Iliopoulos term induced by non-zero gauge flux leads to a T-brane configuration. Expanding the D7-brane action around this T-brane background in the presence of three-form supersymmetry breaking fluxes, we obtain a positive definite contribution to the moduli scalar potential which can be used as an uplifting source for de Sitter vacua. In this way we provide a higher-dimensional understanding of known 4D mechanisms of de Sitter uplifting based on hidden sector F-terms which are non-zero because of D-term stabilisation.
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.
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.
De Sitter's theory of Galilean satellites
NASA Astrophysics Data System (ADS)
Broer, Henk; Zhao, Lei
2016-08-01
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.
Quantum statistical entropy of Schwarzchild-de Sitter spacetime
NASA Astrophysics Data System (ADS)
Zhao, Ren; Zhang, Li-Chun; Zhao, Hui-Hua
2012-10-01
Using the quantum statistical method, we calculate quantum statistical entropy between the black hole horizon and the cosmological horizon in Schwarzchild spacetime and derive the expression of quantum statistical entropy in de Sitter spacetime. Under the Unruh-Verlinde temperature of Schwarzchild-de Sitter spacetime in the entropic force views, we obtain the expression of quantum statistical entropy in de Sitter spacetime. It is shown that in de Sitter spacetime quantum statistical entropy is the sum of thermodynamic entropy corresponding black hole horizon and the one corresponding cosmological horizon. And the correction term of de Sitter spacetime entropy is obtained. Therefore, it is confirmed that the black hole entropy is the entropy of quantum field outside the black hole horizon. The entropy of de Sitter spacetime is the entropy of quantum field between the black hole horizon and the cosmological horizon.
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.
De Sitter Space Without Dynamical Quantum Fluctuations
NASA Astrophysics Data System (ADS)
Boddy, Kimberly K.; Carroll, Sean M.; Pollack, Jason
2016-03-01
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.
Compactifying de Sitter space naturally selects a small cosmological constant
NASA Astrophysics Data System (ADS)
Brown, Adam R.; Dahlen, Alex; Masoumi, Ali
2014-12-01
We study compactifications of D -dimensional de Sitter space with a q -form flux down to D -N q dimensions. We show that for (N -1 )(q -1 )≥2 there are double-exponentially or even infinitely many compact de Sitter vacua, and that their effective cosmological constants accumulate at zero. This population explosion of Λ ≪1 de Sitters arises by a mechanism analogous to natural selection.
The Role of Sitters in Delirium: an Update
Carr, Frances M.
2013-01-01
Purpose The concept behind constant observation is not new. Whilst traditionally performed by nursing staff, it is now commonly performed by sitters. Details surrounding the usage, job description, training, clinical and cost effectiveness of sitters are not known; hence the reason for this review. Methods A literature search was performed in MEDLINE, Cochrane Database of Systematic Reviews, and PubMed from the years 1960 to October 2011. The definition for sitter used in the articles was accepted for this review. Results From this review, it is evident that sitters are being employed in a variety of settings. The question of which type of person would provide the most benefit in the sitter role is still not clear; whilst sitters have typically included family and volunteers, it may be trained volunteers who may offer the most cost-effective solution. The paucity of information available regarding the training and assessments of sitters and the lack of formal guidelines regulating sitters’ use results in a lack of information available regarding these sitters, and current available evidence is conflicting regarding the benefits in terms of cost and clinical outcome. The only strong evidence relating to clinical benefit comes from the use of fully-trained sitters as part of a multi-interventional program (i.e., HELP) Conclusions Current evidence supports a role for the sitter as part of the management of patients with delirium. The most cost-effective sitter role appears to be trained volunteers. Further research is needed to determine the specific type of training required for the sitter role. The creation of a national set of regulations or guidelines would provide safeguards in the industry to ensure safe and effective patient care. PMID:23440038
A new vacuum state in de Sitter space
NASA Astrophysics Data System (ADS)
Pfautsch, Jonathan D.
1982-11-01
We present a new vacuum state which can be defined in a region of de Sitter space. This region corresponds to a K=-1 Robertson-Walker coordinatization of de Sitter space. The renormalized expectation value of the stress tensor for the conformally invariant massless scalar field in this vacuum is evaluated, and is found to differ from the corresponding result in the usual de Sitter-invariant vacuum by the absence of a pure radiation term. We also indicate that this can be accounted for by regarding the de Sitter-invariant vacuum as a thermal state relative to the new vacuum.
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.
Generalized elastica on 2-dimensional de Sitter space S12
NASA Astrophysics Data System (ADS)
Huang, Rongpei; Yu, Junyan
2016-02-01
In this paper, the extremals of curvature energy actions on non-null regular curves in 2-dimensional de Sitter space are studied. We completely solve the Euler-Lagrange equation by quadratures. By using the Killing field, we construct three special coordinate systems and express the generalized elastica in 2-dimensional de Sitter space S12 by integral explicitly.
Dirac oscillator and nonrelativistic Snyder-de Sitter algebra
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.
Dirac oscillator and nonrelativistic Snyder-de Sitter algebra
NASA Astrophysics Data System (ADS)
Stetsko, M. M.
2015-01-01
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.
Discrete symmetries and de Sitter spacetime
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.
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.
Constraining de Sitter Space in String Theory.
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. PMID:26317710
de Sitter Vacua via Consistent D Terms
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.
de Sitter vacua via consistent terms.
Villadoro, Giovanni; Zwirner, Fabio
2005-12-01
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. PMID:16384294
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.
Graviton propagator in a general invariant gauge on de Sitter
Mora, P. J.; Woodard, R. P.; Tsamis, N. C.
2012-12-15
We construct the graviton propagator on de Sitter background in the one parameter family of exact, de Sitter invariant gauges. Our result takes the form of a universal spin two part and a gauge dependent spin zero part. Scalar equations are derived for the structure functions of each part. There is no de Sitter invariant solution for either structure function, although the de Sitter breaking contribution to the spin zero part may drop out for certain choices of the gauge parameter. Our results imply that de Sitter breaking is universal for the graviton propagator, and hence that there is an error in the contrary results derived by analytic continuation of average gauge fixing techniques.
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.
de Sitter symmetry of Neveu-Schwarz spinors
NASA Astrophysics Data System (ADS)
Epstein, Henri; Moschella, Ugo
2016-05-01
We study the relations between Dirac fields living on the 2-dimensional Lorentzian cylinder and the ones living on the double-covering of the 2-dimensional de Sitter manifold, here identified as a certain coset space of the group SL(2 , R). We show that there is an extended notion of de Sitter covariance only for Dirac fields having the Neveu-Schwarz anti-periodicity and construct the relevant cocycle. Finally, we show that the de Sitter symmetry is naturally inherited by the Neveu-Schwarz massless Dirac field on the cylinder.
Neutrino Tunneling from NUT Kerr Newman de Sitter Black Hole
NASA Astrophysics Data System (ADS)
Yang, Nan; Yang, Juan; Li, Jin
2013-08-01
In this paper, the method of semi-classical is applied to explore the Hawking radiation of a NUT-Kerr-Newman de Sitter Black Hole from tunneling point of view. The Hamilton-Jacobi equation in NUT-Kerr-Newman de Sitter space time is derived by the method presented by Lin and Yang (Chin. Phys. B, 20:110403, 2011). We obtain the Hawking temperatures at the event horizon and cosmological horizon and we also obtain the tunneling probability of neutrino following the semi-classical quantum equation. The results show the common features of NUT-Kerr-Newman de Sitter Black Hole.
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.
Gravitational waves in open de Sitter space
NASA Astrophysics Data System (ADS)
Hawking, S. W.; Hertog, Thomas; Turok, Neil
2000-09-01
We compute the spectrum of primordial gravitational wave perturbations in open de Sitter spacetime. The background spacetime is taken to be the continuation of an O(5) symmetric instanton saddle point of the Euclidean no boundary path integral. The two-point tensor fluctuations are computed directly from the Euclidean path integral. The Euclidean correlator is then analytically continued into the Lorentzian region where it describes the quantum mechanical vacuum fluctuations of the graviton field. Unlike the results of earlier work, the correlator is shown to be unique and well behaved in the infrared. We show that the infrared divergence found in previous calculations is due to the contribution of a discrete gauge mode inadvertently included in the spectrum.
Ghost inflation and de Sitter entropy
NASA Astrophysics Data System (ADS)
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.
Perdurance of multiply connected de Sitter space
NASA Astrophysics Data System (ADS)
González-Díaz, Pedro F.
1999-06-01
This paper deals with a study of the effects that spherically symmetric first-order metric perturbations and vacuum quantum fluctuations have on the stability of the multiply connected de Sitter spacetime recently proposed by Gott and Li. It is the main conclusion of this study that although such a spacetime is stable to the classical metric perturbations for any size of the nonchronal region, it is only stable against the quantum fluctuations of vacuum if the size of the multiply connected region is of the order of the Planck scale. Therefore, boundary conditions for the state of the universe based on the notion that the universe created itself in a regime where closed timelike curves were active and stable still appear to be physically and philosophically well supported as are those boundary conditions relying on the notion that the universe was created out of nothing.
A de Sitter tachyon thick braneworld
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.
On higher spin symmetries in de Sitter QFTs
NASA Astrophysics Data System (ADS)
Costa, Renato; Morrison, Ian A.
2016-03-01
We consider the consequences of global higher-spin symmetries in quantum field theories on a fixed de Sitter background of spacetime dimension D ≥ 3. These symmetries enhance the symmetry group associated with the isometries of the de Sitter background and thus strongly constrain the dynamics of the theory. In particular, we consider the case when a higher spin charge acts linearly on a scalar operator to leading order in a Fefferman-Graham expansion near the future/past conformal boundaries. We show that this implies that the expectation values of the operator inserted near the boundaries are asymptotically Gaussian. Thus, these operators have trivial cosmological spectra, and on global de Sitter these operators have only Gaussian correlations between operators inserted near future/past infinity. The latter result may be interpreted as an analogue of the Coleman-Mandula theorem for QFTs on de Sitter spacetime.
Breaking of de Sitter invariance in quantum cosmological gravity
NASA Astrophysics Data System (ADS)
Kleppe, Gary
1993-11-01
The effects of de Sitter transformations on linearized quantum gravity in a de Sitter space background are worked out explicitly. It is shown that the linearized solutions are closed under the transformations of the de Sitter group. To do this it is necessary to use a compensating gauge transformation to return the transformed solution to the original gauge. It is then shown that the form of the graviton propagator in this background, as found by Tsamis and Woodard, is not de Sitter invariant, and no suitable invariant propagator exists, even when gauge transformations which compensate for the noninvariant gauge choice are introduced. This leads us to conclude that the vacuum is not invariant. Address after 1 August 1993: Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA.
NASA Astrophysics Data System (ADS)
Baxter, J. Erik
2016-02-01
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.
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.
NASA Astrophysics Data System (ADS)
Farakos, K.; Kouretsis, A. P.; Pasipoularides, P.
2009-09-01
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), ϕ(r), and V(ϕ(r)). Only the functions ϕ(r) and a(r) are determined analytically, while the functions f(r) and V(ϕ(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.
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.
General aspects of the de Sitter phase
NASA Astrophysics Data System (ADS)
Imponente, G.; Montani, G.
2005-10-01
We present a detailed discussion of the inflationary scenario in the context of inhomogeneous cosmologies. After a review of the fundamental features characterizing the inflationary model, as referred to a homogeneous and isotropic Universe, we develop a generalization in view of including small inhomogeneous corrections in the theory. A second step in our discussion is devoted to show that the inflationary scenario provides a valuable dynamical “bridge” between a generic Kasner-like regime and a homogeneous and isotropic Universe in the horizon scale. This result is achieved by solving the Hamilton-Jacobi equation for a Bianchi IX model in the presence of a cosmological space-dependent term. In this respect, we construct a quasi-isotropic inflationary solution based on the expansion of the Einstein equations up to first two orders of approximation, in which the isotropy of the Universe is due to the dominance of the scalar field kinetic term; the first order of approximation corresponds to the inhomogeneous corrections and is driven by the matter evolution. We show how such a quasi-isotropic solution contains a certain freedom in fixing the space functions involved in the problem. The main physical issue of this analysis corresponds to outline the impossibility for the classical origin of density perturbations, due to the exponential decay of the matter term during the de Sitter phase.
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.
Thermal interpretation of infrared dynamics in de Sitter
NASA Astrophysics Data System (ADS)
Rigopoulos, Gerasimos
2016-07-01
The infrared dynamics of a light, minimally coupled scalar field in de Sitter spacetime with Ricci curvature R = 12H2, averaged over horizon sized regions of physical volume VH = (4π/3)(1/H)3, can be interpreted as Brownian motion in a medium with de Sitter temperature TDS = hbarH/2π. We demonstrate this by directly deriving the effective action of scalar field fluctuations with wavelengths larger than the de Sitter curvature radius and generalizing Starobinsky's seminal results on stochastic inflation. The effective action describes stochastic dynamics and the fluctuating force drives the field to an equilibrium characterized by a thermal Gibbs distribution at temperature TDS which corresponds to a de Sitter invariant state. Hence, approach towards this state can be interpreted as thermalization. We show that the stochastic kinetic energy of the coarse-grained description corresponds to the norm of ∂μphi and takes a well defined value per horizon volume ½langle(∇phi)2rangle = ‑ ½TDS/VH. This approach allows for the non-perturbative computation of the de Sitter invariant stress energy tensor langleTμνrangle for an arbitrary scalar potential.
Vacua and correlators in hyperbolic de Sitter space
NASA Astrophysics Data System (ADS)
Dimitrakopoulos, Fotios V.; Kabir, Laurens; Mosk, Benjamin; Parikh, Maulik; van der Schaar, Jan Pieter
2015-06-01
We study the power- and bi-spectrum of vacuum fluctuations in a hyperbolic section of de Sitter space, comparing two states of physical interest: the Bunch-Davies and hyperbolic vacuum. We introduce a one-parameter family of de Sitter hyperbolic sections and their natural vacua, and identify a limit in which it reduces to the planar section and the corresponding Bunch-Davies vacuum state. Selecting the Bunch-Davies vacuum for a massless scalar field implies a mixed reduced density matrix in a hyperbolic section of de Sitter space. We stress that in the Bunch-Davies state the hyperbolic de Sitter n-point correlation functions have to match the planar de Sitter n-point correlation functions. The expressions for the planar and hyperbolic Bunch-Davies correlation functions only appear different because of the transformation from planar to hyperbolic coordinates. Initial state induced deviations from the standard inflationary predictions are instead obtained by considering the pure hyperbolic vacuum, as we verify explicitly by computing the power- and bi-spectrum. For the bi-spectrum in the hyperbolic vacuum we find that the corrections as compared to the standard Bunch-Davies result are not enhanced in specific momentum configurations and strongly suppressed for momenta large compared to the hyperbolic curvature scale. We close with some final remarks, in particular regarding the implications of these results for more realistic inflationary bubble scenarios.
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.
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.
Super-gauge field in de Sitter universe
NASA Astrophysics Data System (ADS)
Parsamehr, S.; Enayati, M.; Takook, M. V.
2016-05-01
The Gupta-Bleuler triplet for a vector-spinor gauge field is presented in the de Sitter ambient space formalism. The invariant space of field equation solutions is obtained with respect to an indecomposable representation of the de Sitter group. By using the general solution of the massless spin-3/2 field equation, the vector-spinor quantum field operator and its corresponding Fock space is constructed. The quantum field operator can be written in terms of the vector-spinor polarization states and a quantum conformally coupled massless scalar field, which is constructed on Bunch-Davies vacuum state. The two-point function is also presented, which is de Sitter covariant and analytic.
Super-Hubble de Sitter fluctuations and the dynamical RG
NASA Astrophysics Data System (ADS)
Burgess, C. P.; Leblond, L.; Holman, R.; Shandera, S.
2010-03-01
Perturbative corrections to correlation functions for interacting theories in de Sitter spacetime often grow secularly with time, due to the properties of fluctuations on super-Hubble scales. This growth can lead to a breakdown of perturbation theory at late times. We argue that Dynamical Renormalization Group (DRG) techniques provide a convenient framework for interpreting and resumming these secularly growing terms. In the case of a massless scalar field in de Sitter with quartic self-interaction, the resummed result is also less singular in the infrared, in precisely the manner expected if a dynamical mass is generated. We compare this improved infrared behavior with large-N expansions when applicable.
(Anti-)evaporation of Schwarzschild-de Sitter black holes
NASA Astrophysics Data System (ADS)
Bousso, Raphael; Hawking, Stephen W.
1998-02-01
We study the quantum evolution of black holes immersed in a de Sitter background space. For black holes whose size is comparable to that of the cosmological horizon, this process differs significantly from the evaporation of asymptotically flat black holes. Our model includes the one-loop effective action in the s-wave and large N approximation. Black holes of the maximal mass are in equilibrium. Unexpectedly, we find that nearly maximal quantum Schwarzschild-de Sitter black holes anti-evaporate. However, there is a different perturbative mode that leads to evaporation. We show that this mode will always be excited when a pair of cosmological holes nucleates.
Smooth transitions from the Schwarzschild vacuum to de Sitter space
Conboy, Steven; Lake, Kayll
2005-06-15
We provide an infinity of spacetimes which contain part of both the Schwarzschild vacuum and de Sitter space. The transition, which occurs below the Schwarzschild event horizon, involves only boundary surfaces (no surface layers). An explicit example is given in which the weak and strong energy conditions are satisfied everywhere (except in the de Sitter section) and the dominant energy condition is violated only in the vicinity of the boundary to the Schwarzschild section. The singularity is avoided by way of a change in topology in accord with a theorem due to Borde.
How to use retarded Green's functions in de Sitter spacetime
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.
Consistency of scalar potentials from quantum de Sitter space
NASA Astrophysics Data System (ADS)
Espinosa, José R.; Fortin, Jean-François; Trépanier, Maxime
2016-06-01
Consistency of the unconventional view of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom requires that Coleman-De Luccia tunneling rates to vacua with negative cosmological constant should be interpreted as recurrences to low-entropy states. This demand translates into two constraints, or consistency conditions, on the scalar potential that are generically as follows: (1) the distance in field space between the de Sitter vacuum and any other vacuum with negative cosmological constant must be of the order of the reduced Planck mass or larger and (2) the fourth root of the vacuum energy density of the de Sitter vacuum must be smaller than the fourth root of the typical scale of the scalar potential. These consistency conditions shed a different light on both outstanding hierarchy problems of the standard model of particle physics: the scale of electroweak symmetry breaking and the scale of the cosmological constant. Beyond the unconventional interpretation of quantum de Sitter space, we complete the analytic understanding of the thin-wall approximation of Coleman-De Luccia tunneling, extend its numerical analysis to generic potentials and discuss the role of gravity in stabilizing the standard model potential.
Snyder-de Sitter model from two-time physics
Carrisi, M. C.; Mignemi, S.
2010-11-15
We show that the symplectic structure of the Snyder model on a de Sitter background can be derived from two-time physics in seven dimensions and propose a Hamiltonian for a free particle consistent with the symmetries of the model.
Further investigations of the Kerr--de Sitter space
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.
Quantum Vacuum Instability of ``Eternal'' de Sitter Space
NASA Astrophysics Data System (ADS)
Mottola, Emil
2015-04-01
The Euclidean or Bunch-Davies state of quantum fields in global de Sitter space is shown to be unstable to small perturbations, even for a massive free field with no self-interactions. There are perturbations of this state with arbitrarily small energy density at early times that is exponentially blueshifted in the contracting phase of ``eternal'' de Sitter space, and becomes large enough to disturb the classical geometry through the semiclassical Einstein eqs. at later times. In the closely analogous case of a constant, uniform electric field, a time symmetric state equivalent to the de Sitter invariant one is constructed, which is also not a stable vacuum state under perturbations. The role of a quantum anomaly in the growth of perturbations and symmetry breaking is emphasized in both cases. The anomaly stress tensor shows that states invariant under the O(4) subgroup of the de Sitter group are also unstable to perturbations of lower spatial symmetry, implying that both the O(4) subgroup are broken by quantum fluctuations. Consequences of this result for cosmology and the problem of vacuum energy will be discussed.
Inflation in Non-de Sitter Background with Coherent States
NASA Astrophysics Data System (ADS)
Yusofi, E.; Mohsenzadeh, M.; M. R., Tanhayi
2016-03-01
We use the excited coherent states built over the initial non-de Sitter modes, to study the modification of spectra of primordial scalar fluctuation. Non-de Sitter modes are actually the asymptotic solution of the inflaton field equation [J. High Energy Phys. 09 (2014) 020]. We build excited coherent states over the non-de Sitter modes and despite the lack of interactions in the Lagrangian, we find a non-zero one-point function. It is shown that the primordial non-Gaussianity resulting from excited-de Sitter modes depend both of time and background space-time. It is very tiny of order (≤ 10-24), at the Planck initial fixed time that confirmed by resent observations for single field inflation but it grows in the present epoch. Moreover, our results at the leading order are similar to what obtained with general initial states and in the dS limit leads to standard results [J. Cosmol. Astropart. Phys. 1202 (2012) 005]. We will show that the non-dS modes and its resulting spectrum are more usable for far past time limit.
Macroscopicity and classicality of quantum fluctuations in de Sitter space
Wada, S.
1988-08-01
On the basis of the non-probabilistic interpretation of quantum mechanics, the authors define ''macroscopicity'' and ''classicality'' of quantum fluctuations as closely related but separate concepts. Then these properties are examined in quantum states (wave functions) of matter fields in de Sitter spacetime.
Macroscopicity and Classicality of Quantum Fluctuations in de Sitter Space
NASA Astrophysics Data System (ADS)
Wada, Sumio
On the basis of the non-probabilistic interpretation of quantum mechanics, we define “macroscopicity” and “classicality” of quantum fluctuations as closely related but separate concepts. Then these properties are examined in quantum states (wave functions) of matter fields in de Sitter spacetime.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Definition of âpublic offeringâ as used in section 7(d) of the Act with respect to certain Canadian tax-deferred retirement savings accounts. 270.7d-2 Section 270.7d-2 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) RULES AND...
NASA Astrophysics Data System (ADS)
Singh, Abhishek K.; Pandey, K. Priyabrat; Singh, Sunita; Kar, Supriya
2013-05-01
The U(1) gauge dynamics on a D 4-brane is revisited, with a two form, to construct an effective curvature theory in a second order formalism. We exploit the local degrees in a two form, and modify its dynamics in a gauge invariant way, to incorporate a non-perturbative metric fluctuation in an effective D 4-brane. Interestingly, the near horizon D 4-brane is shown to describe an asymptotic Anti de Sitter (AdS) in a semi-classical regime. Using Weyl scaling(s), we obtain the emergent rotating geometries leading to primordial de Sitter (dS) and AdS vacua in a quantum regime. Under a discrete transformation, we re-arrange the mixed dS patches to describe a Schwazschild-like dS (SdS) and a topological-like dS (TdS) black holes. We analyze SdS vacuum for Hawking radiations to arrive at Nariai geometry, where a discrete torsion forms a condensate. We perform thermal analysis to identify Nariai vacuum with a TdS. Investigation reveals an AdS patch within a thermal dS brane, which may provide a clue to unfold dS/CFT. In addition, the role of dark energy, sourced by a discrete torsion, in the dS vacua is investigated using Painleve geometries. It is argued that a D-instanton pair is created by a discrete torsion, with a Big Bang/Crunch, at the past horizon in a pure dS. Nucleation, of brane/anti-brane pair(s), is qualitatively analyzed to construct an effective space-time on a D 4-brane and its anti brane. Analysis re-assures the significant role played by a non-zero mode, of NS-NS two form, to generalize the notion of branes within a brane.
Fermionic Schwinger effect and induced current in de Sitter space
NASA Astrophysics Data System (ADS)
Hayashinaka, Takahiro; Fujita, Tomohiro; Yokoyama, Jun'ichi
2016-07-01
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.
Schwinger effect and backreaction in de Sitter spacetime
NASA Astrophysics Data System (ADS)
Stahl, Clément; Xue, She-Sheng
2016-09-01
We consider the particle-antiparticle pairs produced by both a strong electric field and de Sitter curvature. We investigate in 1 + 1 D the backreaction of the pairs on the electromagnetic field. To do so we describe the canonical quantization of an electromagnetic field in de Sitter space and add in the Einstein-Maxwell equation the fermionic current induced by the pairs. After solving this equation, we find that the electric field gets either damped or unaffected depending on the value of the pair mass and the gauge coupling. No enhancement of the electromagnetic field to support a magnetogenesis scenario is found. The physical picture is that the Schwinger pairs locally created screen the production and amplification of the electromagnetic field. However, if one considers light bosons created by the Schwinger mechanism, we report a solution to the Einstein-Maxwell equation with an enhancement of the electromagnetic field. This solution could be a new path to primordial magnetogenesis.
Gravitomagnetic effects in Kerr-de Sitter space-time
Iorio, Lorenzo; Ruggiero, Matteo Luca E-mail: matteo.ruggiero@polito.it
2009-03-15
We explicitly worked out the orbital effects induced on the trajectory of a test particle by the the weak-field approximation of the Kerr-de Sitter metric. It results that the node, the pericentre and the mean anomaly undergo secular precessions proportional to k. We used such theoretical predictions and the latest observational determinations of the non-standard precessions of the perihelia of the inner planets of the Solar System to put a bound on k getting k {<=} 10{sup -29} m{sup -2}. The node rate of the LAGEOS Earth's satellite yields k {<=} 10{sup -26} m{sup -2}. The periastron precession of the double pulsar PSR J0737-3039A/B allows to obtain k {<=} 3 Multiplication-Sign 10{sup -21} m{sup -2}. Interpreting k as a cosmological constant {Lambda}, it turns out that such constraints are weaker than those obtained from the Schwarzschild-de Sitter metric.
Quantum nonthermal radiation of nonstationary rotating de Sitter cosmological model
NASA Astrophysics Data System (ADS)
Meitei, Irom Ablu; Singh, T. Ibungochouba; Singh, K. Yugindro
2014-08-01
Using the Hamilton-Jacobi method a study of quantum nonthermal radiation of nonstationary rotating de Sitter cosmological model is carried out. It is shown that there exist seas of positive and negative energy states in the vicinity of the cosmological event horizon and there also exists a forbidden energy gap between the two seas. The forbidden energy gap vanishes on the surface of the cosmological event horizon so that the positive and negative energy levels overlap. The width of the forbidden energy gap and the energy of the particle at the cosmological event horizon are found to depend on the cosmological constant, the rotation parameter, positions of the particle and the cosmological event horizon, angular momentum of the particle, evaporation rate and shape of the cosmological event horizon. The tunneling probability of the emitted particles constituting Hawking radiation is also deduced for stationary nonrotating de Sitter cosmological model and the standard Hawking temperature is recovered.
de Sitter Vacua from an Anomalous Gauge Symmetry
NASA Astrophysics Data System (ADS)
Buchmuller, Wilfried; Dierigl, Markus; Ruehle, Fabian; Schweizer, Julian
2016-06-01
We find a new class of metastable de Sitter solutions in compactifications of six-dimensional supergravity motivated by type IIB or heterotic string vacua. Two Fayet-Iliopoulos terms of a local U(1) symmetry are generated by magnetic flux and by the Green-Schwarz term canceling the gauge anomalies, respectively. The interplay between the induced D term, the moduli dependence of the effective gauge coupling, and a nonperturbative superpotential stabilizes the moduli and determines the size of the extra dimensions.
Semiclassical fermion pair creation in de Sitter spacetime
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.
Hawking radiation of the Vaidya Bonner de Sitter black hole
NASA Astrophysics Data System (ADS)
Chen, Deyou; Yang, Shuzheng
2007-08-01
Considering the unfixed background space-time and the self-gravitational interaction, we view the Hawking radiation of the Vaidya Bonner de Sitter black hole by the Hamilton Jacobi method and the radial geodesic method. The result shows the tunneling rate is related not only to the change of Bekenstein Hawking entropy but also to the integral of the black hole mass and charge, which does not satisfy the unitary theory and is not in accordance with the known result.
The solar photon thruster as a terrestrial pole sitter.
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. PMID:15220163
Dynamics of test bodies with spin in de Sitter spacetime
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.
Solutions of minimal four-dimensional de Sitter supergravity
NASA Astrophysics Data System (ADS)
Gutowski, J. B.; Sabra, W. A.
2010-12-01
Pseudo-supersymmetric solutions of minimal N = 2, D = 4 de Sitter supergravity are classified using spinorial geometry techniques. We find three classes of solutions. The first class of solution consists of geometries which are fibrations over a three-dimensional manifold equipped with a Gauduchon-Tod structure. The second class of solution is the cosmological Majumdar-Papapetrou solution of Kastor and Traschen, and the third corresponds to gravitational waves propagating in the Nariai cosmology.
Incompressible fluids of the de Sitter horizon and beyond
NASA Astrophysics Data System (ADS)
Anninos, Dionysios; Anous, Tarek; Bredberg, Irene; Ng, Gim Seng
2012-05-01
There are (at least) two surfaces of particular interest in eternal de Sitter space. One is the timelike hypersurface constituting the lab wall of a static patch observer and the other is the future boundary of global de Sitter space. We study both linear and non-linear deformations of four-dimensional de Sitter space which obey the Einstein equation. Our deformations leave the induced conformal metric and trace of the extrinsic curvature unchanged for a fixed hypersurface. This hypersurface is either timelike within the static patch or spacelike in the future diamond. We require the deformations to be regular at the future horizon of the static patch observer. For linearized perturbations in the future diamond, this corresponds to imposing incoming flux solely from the future horizon of a single 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 for both spacelike and timelike hypersurfaces. We then study, at the level of linearized gravity, the change in the discrete dispersion relation as we push the timelike hypersurface toward the worldline of the static patch. Finally, we study the spectrum of linearized solutions as the spacelike slices are pushed to future infinity and relate our calculations to analogous ones in the context of massless topological black holes in AdS4.
Probing Planckian physics in de Sitter space with quantum correlations
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.
Closed conformal Killing Yano tensor and the uniqueness of generalized Kerr NUT de Sitter spacetime
NASA Astrophysics Data System (ADS)
Houri, Tsuyoshi; Oota, Takeshi; Yasui, Yukinori
2009-02-01
The higher-dimensional Kerr NUT de Sitter spacetime describes the general rotating asymptotically de Sitter black hole with NUT parameters. It is known that such a spacetime possesses a rank-2 closed conformal Killing Yano (CKY) tensor as a 'hidden' symmetry which provides the separation of variables for the geodesic equations and Klein Gordon equations. We present a classification of higher-dimensional spacetimes admitting a rank-2 closed CKY tensor. This provides a generalization of the Kerr NUT de Sitter spacetime. In particular, we show that the Kerr NUT de Sitter spacetime is the only spacetime with a non-degenerate CKY tensor.
Overexpression of PRL7D1 in Leydig Cells Causes Male Reproductive Dysfunction in Mice.
Liu, Yaping; Su, Xingyu; Hao, Jie; Chen, Maoxin; Liu, Weijia; Liao, Xiaogang; Li, Gang
2016-01-01
Prolactin family 7, subfamily d, member 1 (PRL7D1) is found in mouse placenta. Our recent work showed that PRL7D1 is also present in mouse testis Leydig cells, and the expression of PRL7D1 in the testis exhibits an age-related increase. In the present study, we generated transgenic mice with Leydig cell-specific PRL7D1 overexpression to explore its function during male reproduction. Prl7d1 male mice exhibited subfertility as reflected by reduced sperm counts and litter sizes. The testes from Prl7d1 transgenic mice appeared histologically normal, but the frequency of apoptotic germ cells was increased. Prl7d1 transgenic mice also had lower testosterone concentrations than wild-type mice. Mechanistic studies revealed that Prl7d1 transgenic mice have defects in the testicular expression of steroidogenic acute regulatory protein (STAR) and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B). Further studies revealed that PRL7D1 overexpression affected the expression of transferrin (TF) in Sertoli cells. These results suggest that PRL7D1 overexpression could lead to increased germ cell apoptosis and exert an inhibitory effect on testosterone production in Leydig cells by reducing the expression of certain steroidogenic-related genes. In addition, PRL7D1 appears to have important roles in the function of Sertoli cells, which, in turn, affects male fertility. We conclude that the expression level of PRL7D1 is associated with the reproductive function of male mice. PMID:26771609
Overexpression of PRL7D1 in Leydig Cells Causes Male Reproductive Dysfunction in Mice
Liu, Yaping; Su, Xingyu; Hao, Jie; Chen, Maoxin; Liu, Weijia; Liao, Xiaogang; Li, Gang
2016-01-01
Prolactin family 7, subfamily d, member 1 (PRL7D1) is found in mouse placenta. Our recent work showed that PRL7D1 is also present in mouse testis Leydig cells, and the expression of PRL7D1 in the testis exhibits an age-related increase. In the present study, we generated transgenic mice with Leydig cell-specific PRL7D1 overexpression to explore its function during male reproduction. Prl7d1 male mice exhibited subfertility as reflected by reduced sperm counts and litter sizes. The testes from Prl7d1 transgenic mice appeared histologically normal, but the frequency of apoptotic germ cells was increased. Prl7d1 transgenic mice also had lower testosterone concentrations than wild-type mice. Mechanistic studies revealed that Prl7d1 transgenic mice have defects in the testicular expression of steroidogenic acute regulatory protein (STAR) and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B). Further studies revealed that PRL7D1 overexpression affected the expression of transferrin (TF) in Sertoli cells. These results suggest that PRL7D1 overexpression could lead to increased germ cell apoptosis and exert an inhibitory effect on testosterone production in Leydig cells by reducing the expression of certain steroidogenic-related genes. In addition, PRL7D1 appears to have important roles in the function of Sertoli cells, which, in turn, affects male fertility. We conclude that the expression level of PRL7D1 is associated with the reproductive function of male mice. PMID:26771609
Kinematics of particles with quantum-de Sitter-inspired symmetries
NASA Astrophysics Data System (ADS)
Barcaroli, Leonardo; Gubitosi, Giulia
2016-06-01
We present the first detailed study of the kinematics of free relativistic particles whose symmetries are compatible with the ones described by a quantum deformation of the de Sitter algebra, known as q -de Sitter Hopf algebra. In such algebra, the quantum deformation parameter is a function of the Planck length ℓ and the de Sitter radius H-1, such that when the Planck length vanishes, the algebra reduces to the de Sitter algebra, while when the de Sitter radius is sent to infinity, one recovers the κ -Poincaré Hopf algebra. In the first limit, the picture is that of a particle with trivial momentum space geometry moving on de Sitter spacetime; in the second one, the picture is that of a particle with de Sitter momentum space geometry moving on Minkowski spacetime. When both the Planck length and the inverse of the de Sitter radius are nonzero, effects due to spacetime curvature and nontrivial momentum space geometry are both present and affect each other. The particles' motion is then described in a full phase-space picture. We find that redshift effects that are usually associated with spacetime curvature become energy dependent. Also, the energy dependence of the particles' travel times that is usually associated with momentum space nontrivial properties is modified in a curvature-dependent way.
Gauge theory of a group of diffeomorphisms. II. The conformal and de Sitter groups
NASA Astrophysics Data System (ADS)
Lord, Eric A.
1986-12-01
The extension of Hehl's Poincaré gauge theory to more general groups that include space-time diffeomorphisms is worked out for two particular examples, one corresponding to the action of the conformal group on Minkowski space, and the other to the action of the de Sitter group on de Sitter space, and the effect of these groups on physical fields.
How To Feel Good about Leaving Your Children with A Sitter.
ERIC Educational Resources Information Center
Lane, Jordan
2003-01-01
Presents suggestions to help parents feel at ease when they leave their children with a babysitter, offering tips on: how to find a sitter, scheduling the sitter, paying fairly, laying down the rules, ensuring safety, preparing a list, and providing food. (SM)
Inflation in de Sitter spacetime and CMB large scale anomaly
NASA Astrophysics Data System (ADS)
Zhao, Dong; Li, Ming-Hua; Wang, Ping; Chang, Zhe
2015-09-01
The influence of cosmological constant-type dark energy in the early universe is investigated. This is accommodated by a new dispersion relation in de Sitter spacetime. We perform a global fit to explore the cosmological parameter space by using the CosmoMC package with the recently released Planck TT and WMAP polarization datasets. Using the results from the global fit, we compute a new CMB temperature-temperature (TT) spectrum. The obtained TT spectrum has lower power compared with that based on the ACDM model at large scales. Supported by National Natural Science Foundation of China (11375203)
Reexamination of the Power Spectrum in De Sitter Inflation
NASA Astrophysics Data System (ADS)
Agulló, Iván; Navarro-Salas, José; Olmo, Gonzalo J.; Parker, Leonard
2008-10-01
We find that the amplitude of quantum fluctuations of the invariant de Sitter vacuum coincides exactly with that of the vacuum of a comoving observer for a massless scalar (inflaton) field. We propose redefining the actual physical power spectrum as the difference between the amplitudes of the above vacua. An inertial particle detector continues to observe the Gibbons-Hawking temperature. However, although the resulting power spectrum is still scale-free, its amplitude can be drastically reduced since now, instead of the Hubble’s scale at the inflationary period, it is determined by the square of the mass of the inflaton fluctuation field.
Holographic de Sitter Geometry from Entanglement in Conformal Field Theory
NASA Astrophysics Data System (ADS)
de Boer, Jan; Heller, Michal P.; Myers, Robert C.; Neiman, Yasha
2016-02-01
We demonstrate that, for general conformal field theories (CFTs), the entanglement for small perturbations of the vacuum is organized in a novel holographic way. For spherical entangling regions in a constant time slice, perturbations in the entanglement entropy are solutions of a Klein-Gordon equation in an auxiliary de Sitter (dS) spacetime. The role of the emergent timelike direction in dS spacetime is played by the size of the entangling sphere. For CFTs with extra conserved charges, e.g., higher-spin charges, we show that each charge gives rise to a separate dynamical scalar field in dS spacetime.
Schwarzschild-De Sitter Black Hole from Entropic Viewpoint
NASA Astrophysics Data System (ADS)
Ee, Chang-Young; Eune, Myungseok; Kimm, Kyoungtae; Lee, Daeho
In a Schwarzschild-de Sitter space, we consider an equipotential surface which consists of two holographic screens. Adapting the Bousso-Hawking's reference point of vanishing force, we divide the space into two regions, which are from the reference point to each holographic screen. These two regions can be treated as independent thermodynamical systems, because the Bousso-Hawking reference point with zero temperature behaves like a thermally insulating wall. The entropy obtained in this way agrees with the conventional results: (i) when the holographic screens lie at the black hole and cosmological horizons, (ii) in the Nariai limit.
The deflationary universe: An instability of the de Sitter universe
NASA Astrophysics Data System (ADS)
Barrow, John D.
1986-11-01
The relevance is discussed of the initial value structure of the cosmological problem for inflationary explanations of its present structure. Existing proofs of the cosmic ``no hair'' conjecture are found to make use of an unrealistic strong energy condition on the stress tensor of the matter fields not driving the inflation. It is shown by explicit example that the no hair conjecture fails even in isotropic cosmological models if the strong energy conditions is relaxed. A class of exact cosmological models are given which begin in a de Sitter state but subsequently deflate towards the flat Friedman model. Various implications of these examples are discussed.
Clark, Andrew T.; Smith, Kelley; Muhandiram, Ranjith; Edmondson, Stephen P.; Shriver, John W.
2007-01-01
Sac7d and Sso7d are homologous, hyperthermophile proteins with a high density of charged surface residues and potential ion pairs. To determine the relative importance of specific amino acid side chains in defining the stability and function of these Archaeal chromatin proteins, pKas were measured for all of the acidic residues in both proteins using 13C NMR chemical shifts. The stability of Sso7d enabled titrations to pH 1 under low salt conditions. Two aspartate residues in Sso7d (D16 and D35) and a single glutamate residue (G54) showed significantly perturbed pKa values in low salt, indicating that the observed pH dependence of stability was primarily due to these three residues. The pH dependence of backbone amide NMR resonances demonstrated that perturbation of all three pKas was primarily the result of side chain-backbone amide hydrogen bonds. Titration data at higher salt for both Sso7d and Sac7d were consistent with this interpretation. Few of the significantly perturbed acidic pKas in Sac7d and Sso7d could be attributed to primarily ion pair or electrostatic interactions. A smaller perturbation of E48 (E47 in Sac7d) was ascribed to an ion pair interaction that may be important in defining the DNA binding surface. The small number (3) of significantly altered pKa values was in good agreement with a linkage analysis of the temperature, pH, and salt dependence of folding. The linkage of the ionization of two or more side chains to protein folding leads to apparent cooperativity in the pH dependence of folding, although each group titrates independently with a Hill coefficient near unity. These results demonstrate that the acid pH dependence of protein stability in these hyperthermophile proteins is due to independent titration of acidic residues with pKas perturbed primarily by hydrogen bonding of the side chain to the backbone. This work demonstrates the need for caution in using structural data alone to argue the importance of ion pairs in stabilizing
Initial states and infrared physics in locally de Sitter spacetime
NASA Astrophysics Data System (ADS)
Larjo, Klaus; Lowe, David A.
2012-02-01
The long wavelength physics in a de Sitter region depends on the initial quantum state. While such long wavelength physics is under control for massive fields near the Hartle-Hawking vacuum state, such initial states make unnatural assumptions about initial data outside the region of causal contact of a local observer. We argue that a reasonable approximation to a maximum entropy state, one that makes minimal assumptions outside an observer’s horizon volume, is one where a cutoff is placed on a surface bounded by timelike geodesics, just outside the horizon. For sufficiently early times, such a cutoff induces secular logarithmic divergences with the expansion of the region. For massive fields, these effects sum to finite corrections at sufficiently late times. The difference between the cutoff correlators and Hartle-Hawking correlators provides a measure of the theoretical uncertainty due to lack of knowledge of the initial state in causally disconnected regions. These differences are negligible for primordial inflation, but can become significant during epochs with very long-lived de Sitter regions, such as we may be entering now.
Auxiliary ``Massless'' Spin-2 Field in De Sitter Universe
NASA Astrophysics Data System (ADS)
Pejhan, H.; Tanhayi, M. R.; Takook, M. V.
2010-09-01
For the tensor field of rank-2 there are two unitary irreducible representation (UIR) in de Sitter (dS) space denoted by Pi^{±}_{2,2} and Pi^{±}_{2,1} (Dixmier in Bull Soc. Math. France 89:9, 1961). In the flat limit only the Pi^{±}_{2,2} coincides to the UIR of Poincaré group, the second one becomes important in the study of conformal gravity. In the previous work, Dirac’s six-cone formalism has been utilized to obtain conformally invariant (CI) field equation for the “massless” spin-2 field in dS space (Dehghani et al. in Phys. Rev. D 77:064028, 2008). This equation results in a field which transformed according to Pi^{±}_{2,1}, we name this field the auxiliary field. In this paper this auxiliary field is considered and also related two-point function is calculated as a product of a polarization tensor and “massless” conformally coupled scalar field. This two-point function is de Sitter invariant.
Rotating, radiating mass imbedded in a de Sitter universe
Hadley, R.H.
1991-01-01
This study presents a new solution to the Einstein field equations for a rotating, radiating mass imbedded in a de Sitter universe, the Kerr de Sitter-Vaidya or KDV line element. Solutions presented were precursers to the new solution. One of these, the Vaidya-Mallett or VM metric is used as a starting point to derive the KDV metric by a method called complexification. The mathematical framework for the KDV metric is the Newman-Penrose formalism, a powerful tool that provides insight into the various properties of the space-time geometry and optical properties of the radiation field. Using this formalism, the metric can be expressed in tetrad form and the Newman-Penrose spin coefficient equations solved for tetrad components of the trace-free Ricci tensor, Ricci scalar, Maxwell tensor, and Weyl tensor. Using the tetrad components of the Weyl tensor, the Petrov type for the gravitational and electromagnetic fields are found. The new solution is shown to be a solution to the Einstein-Maxwell equations for a particular choice of energy-momentum tensor which is studied in detail.
Superluminal Neutrinos from Special Relativity with de Sitter Spacetime Symmetry
NASA Astrophysics Data System (ADS)
Yan, Mu-Lin; Xiao, Neng-Chao; Huang, Wei; Hu, Sen
2012-05-01
We explore the recent OPERA experiment of superluminal neutrinos in the framework of special relativity with de Sitter spacetime symmetry (dS-SR). According to Einstein, a photon is treated as a massless particle in the framework of special relativity. In special relativity (SR) we have the universal parameter c, the photon velocity cphoton and the phase velocity of a light wave in vacuum cwave = λν. Due to the null experiments of Michelson-Morley we have c = cwave. The parameter cphoton is determined by the Noether charges corresponding to the spacetime symmetries of SR. In Einstein's special relativity (E-SR) we have c = cphoton. In dS-SR, i.e. the special relativity with SO(4, 1) de Sitter spacetime symmetry, we have cphoton > c. In this paper, the OPERA datum are examined in the framework of dS-SR. We show that OPERA anomaly is in agreement with the prediction of dS-SR with R≃1.95×1012 l.y. Based on the p-E relation of dS-SR, we also prove that the Cohen and Glashow's argument of possible superluminal neutrino's Cherenkov-like radiation is forbidden. We conclude that OPERA and ICARUS results are consistent and they are explained in the dS-SR framework.
Probing Planckian physics in de Sitter space with quantum correlations
NASA Astrophysics Data System (ADS)
Feng, Jun; Zhang, Yao-Zhong; Gould, Mark D.; Fan, Heng; Sun, Cheng-Yi; Yang, Wen-Li
2014-12-01
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 Hc of negativity and zeros of quantum capacity of quantum channels in de Sitter space has been proved.
One-loop gravitational wave spectrum in de Sitter spacetime
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.
Quasinormal modes in de Sitter space: Plane wave method
NASA Astrophysics Data System (ADS)
Tanhayi, M. Reza
2014-09-01
Recently, in the context of dS/CFT correspondence, quasinormal modes have been put forward to address certain features of this conjecture. In particular, it is argued that the dual states of quasinormal modes are in fact the states of CFT3 which are created by operator insertions. For a scalar field in dS4, quasinormal modes which are singular on the past horizon of the south pole and decay exponentially towards the future have been considered in [G. S. Ng and A. Strominger, Classical Quantum Gravity 30, 104002 (2013); D. L. Jafferis et al., arXiv:1305.5523]; these modes lie in two complex highest-weight representations of the dS4 isometry group. In this work, we present a simple group representation analysis of these modes so that the de Sitter invariance is obviously manifest. By making use of the so-called plane wave method, we will show that the quasinormal modes correspond to one class of the unitary irreducible representation of the de Sitter group. This consideration could be generalized straightforwardly for higher-spin fields and higher dimensions; in particular, we will study the quasinormal modes for gauge and spinor fields, and, in the case of a scalar field, the generalization to higher dimensions is also obtained.
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.
Inhibition and Role of let-7d in Idiopathic Pulmonary Fibrosis
Pandit, Kusum V.; Corcoran, David; Yousef, Hanadie; Yarlagadda, Manohar; Tzouvelekis, Argyris; Gibson, Kevin F.; Konishi, Kazuhisa; Yousem, Samuel A.; Singh, Mandal; Handley, Daniel; Richards, Thomas; Selman, Moises; Watkins, Simon C.; Pardo, Annie; Ben-Yehudah, Ahmi; Bouros, Demosthenes; Eickelberg, Oliver; Ray, Prabir; Benos, Panayiotis V.; Kaminski, Naftali
2010-01-01
Rationale: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and usually lethal fibrotic lung disease characterized by profound changes in epithelial cell phenotype and fibroblast proliferation. Objectives: To determine changes in expression and role of microRNAs in IPF. Methods: RNA from 10 control and 10 IPF tissues was hybridized on Agilent microRNA microarrays and results were confirmed by quantitative real-time polymerase chain reaction and in situ hybridization. SMAD3 binding to the let-7d promoter was confirmed by chromatin immunoprecipitation, electrophoretic mobility shift assay, luciferase assays, and reduced expression of let-7d in response to transforming growth factor-β. HMGA2, a let-7d target, was localized by immunohistochemistry. In mice, let-7d was inhibited by intratracheal administration of a let-7d antagomir and its effects were determined by immunohistochemistry, immunofluorescence, quantitative real-time polymerase chain reaction, and morphometry. Measurements and Main Results: Eighteen microRNAs including let-7d were significantly decreased in IPF. Transforming growth factor-β down-regulated let-7d expression, and SMAD3 binding to the let-7d promoter was demonstrated. Inhibition of let-7d caused increases in mesenchymal markers N-cadherin-2, vimentin, and α-smooth muscle actin (ACTA2) as well as HMGA2 in multiple epithelial cell lines. let-7d was significantly reduced in IPF lungs and the number of epithelial cells expressing let-7d correlated with pulmonary functions. HMGA2 was increased in alveolar epithelial cells of IPF lungs. let-7d inhibition in vivo caused alveolar septal thickening and increases in collagen, ACTA2, and S100A4 expression in SFTPC (pulmonary-associated surfactant protein C) expressing alveolar epithelial cells. Conclusions: Our results indicate a role for microRNAs in IPF. The down-regulation of let-7d in IPF and the profibrotic effects of this down-regulation in vitro and in vivo suggest a key
Plane waves in de Sitter space: Spin-1/2 field
NASA Astrophysics Data System (ADS)
Reza Tanhayi, M.; Mohsenzadeh, M.; Yusofi, E.
2016-06-01
We employ the coordinate-independent plane wave solution in de Sitter space to study the spin-1/2 particle production. The so-called plane waves in the zero-curvature limit reduce to the usual plane waves in flat space. Previously in (Int. J. Mod. Phys. D 24, 1550052 (2015)) we used such modes to study the instability of the de Sitter space, here, by explicit calculation, we study the sipn-1/2 particle creation in de Sitter space caused by mixing modes.
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.
Code of Federal Regulations, 2014 CFR
2014-04-01
... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.7d-2 Definition of “public... Canadian law. (3) Eligible Security means a security issued by a Qualified Company that: (i) Is offered to a Participant, or sold to his or her Canadian Retirement Account, in reliance on this section;...
Code of Federal Regulations, 2012 CFR
2012-04-01
... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.7d-2 Definition of “public... Canadian law. (3) Eligible Security means a security issued by a Qualified Company that: (i) Is offered to a Participant, or sold to his or her Canadian Retirement Account, in reliance on this section;...
Code of Federal Regulations, 2011 CFR
2011-04-01
... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.7d-2 Definition of “public... Canadian law. (3) Eligible Security means a security issued by a Qualified Company that: (i) Is offered to a Participant, or sold to his or her Canadian Retirement Account, in reliance on this section;...
Code of Federal Regulations, 2013 CFR
2013-04-01
... COMMISSION (CONTINUED) RULES AND REGULATIONS, INVESTMENT COMPANY ACT OF 1940 § 270.7d-2 Definition of “public... Canadian law. (3) Eligible Security means a security issued by a Qualified Company that: (i) Is offered to a Participant, or sold to his or her Canadian Retirement Account, in reliance on this section;...
Lecture Notes on Interacting Quantum Fields in de Sitter Space
NASA Astrophysics Data System (ADS)
Akhmedov, E. T.
2013-09-01
We discuss peculiarities of quantum fields in de Sitter (dS) space on the example of the self-interacting massive real scalar, minimally coupled to the gravity background. Nonconformal quantum field theories (QFTs) in dS space show very special infrared behavior, which is not shared by quantum fields neither in flat nor in anti-dS space: in dS space loops are not suppressed in comparison with tree level contributions because there are strong infrared corrections. That is true even for massive fields. Our main concern is the interrelation between these infrared effects, the invariance of the QFT under the dS isometry and the (in)stability of dS invariant states (and of dS space itself) under nonsymmetric perturbations.
Lecture Notes on Interacting Quantum Fields in de Sitter Space
NASA Astrophysics Data System (ADS)
Akhmedov, E. T.
2014-10-01
We discuss peculiarities of quantum fields in de Sitter (dS) space on the example of the self-interacting massive real scalar, minimally coupled to the gravity background. Nonconformal quantum field theories (QFTs) in dS space show very special infrared behavior, which is not shared by quantum fields neither in flat nor in anti-dS space: in dS space loops are not suppressed in comparison with tree level contributions because there are strong infrared corrections. That is true even for massive fields. Our main concern is the interrelation between these infrared effects, the invariance of the QFT under the dS isometry and the (in)stability of dS invariant states (and of dS space itself) under nonsymmetric perturbations.
Gauge dependence in QED amplitudes in expanding de Sitter space
NASA Astrophysics Data System (ADS)
Nicolaevici, Nistor
2016-04-01
We consider first-order transition amplitudes in external fields in QED in the expanding de Sitter space and point out that they are gauge dependent quantities. We examine the gauge variations of the amplitudes assuming a decoupling of the interaction at large times, which allows to conclude that the source of the problem lies in the fact that the frequencies of the modes in the infinite future become independent of the comoving momenta. We show that a possibility to assure the gauge invariance of the external field amplitudes is to restrict to potentials which vanish sufficiently fast at infinite times, and briefly discuss a number of options in the face of the possible gauge invariance violation in the full interacting theory.
Brane induced supersymmetry breaking and de Sitter supergravity
NASA Astrophysics Data System (ADS)
Bandos, Igor; Martucci, Luca; Sorokin, Dmitri; Tonin, Mario
2016-02-01
We obtain a four-dimensional supergravity with spontaneously broken super-symmetry allowing for de Sitter vacua by coupling a superspace action of minimal N = 1, D = 4 supergravity to a locally supersymmetric generalization of the Volkov-Akulov goldstino action describing the dynamics of a space-filling non-BPS 3-brane in N = 1, D = 4 superspace. To the quadratic order in the goldstino field the obtained action coincides with earlier constructions of supergravities with nilpotent superfields, while matching the higher-order contributions will require a non-linear redefinition of fields. In the unitary gauge, in which the goldstino field is set to zero, the action coincides with that of Volkov and Soroka. We also show how a nilpotency constraint on a chiral curvature superfield emerges in this formulation.
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.
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.
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.