Spin Interaction under the Collision of Two Kerr-(anti-)de Sitter Black Holes
Gwak, Bogeun
2016-01-01
We have investigated spin interaction under the collision of Kerr-(anti-)de Sitter black holes. The potential of a spin interaction is dependent on the relative rotating directions of the black holes, and this potential can be released as gravitational radiation under the collision. The radiation depends on the cosmological constant and corresponds to the potential of the spin interaction at a limit where one of the black holes is assumed to have small mass and angular momentum. Then, we have shown, approximately, the overall behaviors of the upper bounds on the radiation using thermodynamics. From these bounds, the spin interaction can consistently contribute to the radiation. In addition, the radiation depends on the stability of the black hole synthesized from the collision.
Zero, Normal and Super-radiant Modes for Scalar and Spinor Fields in Kerr-anti de Sitter Spacetime
Kenmoku, Masakatsu; Shigemoto, Kazuyasu; Yoon, Jong Hyuk
2016-01-01
Zero and normal modes for scalar and spinor fields in Kerr-anti de Sitter spacetime are studied as bound state problem with Dirichlet and Neumann boundary conditions. Zero mode is defined as the momentum near the horizon to be zero: $p_{\\rm H}=\\omega-\\Omega_{\\rm H}m=0$, and is shown not to exist as physical state for both scalar and spinor fields. Physical normal modes satisfy the spectrum condition $p_{\\rm H}>0$ as a result of non-existence of zero mode and the analyticity with respect to rotation parameter $a$ of Kerr-anti de Sitter black hole. Comments on the super-radiant modes and the thermodynamics of black hole are given in relation to the spectrum condition for normal modes. Preliminary numerical analysis on normal modes is presented.
Institute of Scientific and Technical Information of China (English)
LIN Kai; ZENG Xiao-Xiong; YANG Shu-Zheng
2008-01-01
Using anomalous viewpoint,we study the Hawking radiation from a kind of topological Kerr Anti-de-Sitter(Kerr AdS)black hole with ode rotational parameter.We employ the covariant gauge and gravitational anomalies.The result supports the Robinson-Wilczek opinion and shows that the Hawking temperature can be correctly determined by cancelling covariant gauge and gravitational anomalies at the horizon.
Kazempour, Sobhan; Soroushfar, Saheb
2016-01-01
In this paper we add a compact dimension to Schwarzschild-(anti-) de sitter and Kerr-(anti-) de sitter spacetimes, which describes (rotating) black string-(anti-) de sitter spacetime. We study the geodesic motion of test particles and light rays in this spacetime. We present the analytical solutions of the geodesic equations in terms of Weierstrass elliptic and Kleinian sigma hyperelliptical functions. We also discuss the possible orbits and classify them according to particle's energy and angular momentum. Moreover, the obtained results, are compared to Schwarzschild-(anti-) de sitter and Kerr-(anti-) de sitter spacetimes.
Unstable Mode Solutions to the Klein-Gordon Equation in Kerr-anti-de Sitter Spacetimes
Dold, Dominic
2017-03-01
For any cosmological constant {Λ = -3/ℓ2 |a|ℓ}. We obtain an analogous result for Neumann boundary conditions if {5/4 < α < 9/4}. Moreover, in the Dirichlet case, one can prove that, for any Kerr-AdS spacetime violating the Hawking-Reall bound, there exists an open family of masses {α} such that the corresponding Klein-Gordon equation permits exponentially growing mode solutions. Our result adopts methods of Shlapentokh-Rothman developed in (Commun. Math. Phys. 329:859-891, 2014) and provides the first rigorous construction of a superradiant instability for negative cosmological constant.
Unstable Mode Solutions to the Klein-Gordon Equation in Kerr-anti-de Sitter Spacetimes
Dold, Dominic
2016-10-01
For any cosmological constant {Λ = -3/ℓ2 |a|ℓ} . We obtain an analogous result for Neumann boundary conditions if {5/4 Rothman developed in (Commun. Math. Phys. 329:859-891, 2014) and provides the first rigorous construction of a superradiant instability for negative cosmological constant.
Unstable mode solutions to the Klein-Gordon equation in Kerr-anti-de Sitter spacetimes
Dold, Dominic
2015-01-01
For any cosmological constant $\\Lambda=-3/\\ell^2|a|\\ell$. We obtain an analogous result for Neumann boundary conditions if $5/4<\\alpha<9/4$. Moreover, in the Dirichlet case, one can prove that, for any Kerr-AdS spacetime violating the Hawking-Reall bound, there exists an open family of masses $\\alpha$ such that the corresponding Klein-Gordon equation permits exponentially growing mode solutions. Our result adopts methods of Shlapentokh-Rothman (see http://arxiv.org/abs/1302.3448) and provides the first rigorous construction of a superradiant instability for negative cosmological constant.
Decay of charged fields in de Sitter spacetime
Smirnov, A A
2004-01-01
We study the decay of charged scalar and spinor fields around Reissner-Nordstrom black holes in de Sitter spacetime through calculations of quasinormal frequencies of the fields. The influence of the parameters of the black hole (charge, mass), of the decaying fields (charge, spin), and of the spacetime (cosmological constant) on the decay is analyzed. The analytic formula for calculation quasinormal frequencies for a large multipole number (eikonal approximation) is derived for the spinor case.
Asymptotic Symmetries and Charges in De Sitter Space
Anninos, Dionysios; Strominger, Andrew
2010-01-01
The asymptotic symmetry group (ASG) at future null infinity (I^+) of four-dimensional de Sitter spacetimes is defined and shown to be given by the group of three-dimensional diffeomorphisms acting on I^+. Finite charges are constructed for each choice of ASG generator together with a two-surface on I^+. A conservation equation is derived relating the evolution of the charges with the radiation flux through I^+.
Asymptotic symmetries and charges in de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Anninos, Dionysios; Ng, Gim Seng; Strominger, Andrew, E-mail: gng@fas.harvard.edu [Center for the Fundamental Laws of Nature, Harvard University, Cambridge, MA 02138 (United States)
2011-09-07
The asymptotic symmetry group (ASG) at future null infinity (I{sup +}) of asymptotically four-dimensional de Sitter spacetimes is defined and shown to be given by the group of three-dimensional diffeomorphisms acting on I{sup +}. Finite charges are constructed for each choice of ASG generator together with a two-surface on I{sup +}. A conservation equation is derived relating the evolution of the charges with the radiation flux through I{sup +}.
Charged scalar gravitational collapse in de Sitter spacetime
Zhang, Cheng-Yong; Zou, De-Cheng; Wang, Bin
2015-01-01
We study the charged scalar collapse in de Sitter spacetimes. With the electric charge, there is one more competitor to join the competition of dynamics in the gravitational collapse. We find that two factors can influence the electric charge. If we just adjust the charge-conjugation, the electric charge effect is always perturbative at the black hole threshold. The electric charge can also be influenced by the initial conditions of perturbations. These initial parameters can be tuned to control the competition in dynamics and present us new and rich physics in the process of gravitational collapse. We give physical explanations on these phenomena found in dynamics. Furthermore we show that the properties of the gravitational collapse are universal and do not depend on spacetime dimensions.
Instability of charged anti-de Sitter black holes
Gwak, Bogeun; Lee, Bum-Hoon; Ro, Daeho
2016-10-01
We have studied the instability of charged anti-de Sitter black holes in four- or higher-dimensions under fragmentation. The unstable black holes under fragmentation can be broken into two black holes. Instability depends not only on the mass and charge of the black hole but also on the ratio between the fragmented black hole and its predecessor. We have found that the near extremal black holes are unstable, and Schwarzschild-AdS black holes are stable. These are qualitatively similar to black holes in four dimensions and higher. The detailed instabilities are numerically investigated.
Instability of Charged Anti-de Sitter Black Holes
Gwak, Bogeun; Ro, Daeho
2015-01-01
We study the instability of charged anti-de Sitter black holes in four or higher-dimension under fragmentation. The instability of fragmentation breaks the black hole into two black holes. We have found that the region near extremal or massive black holes become unstable under fragmentation. These regions depend not only on the mass and charge of initial black hole but also those of the fragmented one. The instability in higher-dimension is qualitatively similar to that of four-dimension. The detailed instabilities are numerically investigated.
(Anti-) de Sitter Electrically Charged Black Hole Solutions in Higher-Derivative Gravity
Lin, Kai; Pavan, A B; Abdalla, E
2016-01-01
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.
LARRAÑAGA, Eduard Alexis
2008-01-01
In this paper we will show that using the cosmological constant as a new thermodynamical state variable, the differential and integral mass formulas of the first law of thermodynamics for asymptotic flat spacetimes can be extended to (2+1) dimensional charged BTZ black holes and charged de Sitter space.
Charged null fluid collapse in anti-de Sitter spacetimes and naked singularities
Ghosh, S G
2000-01-01
We investigate the occurrence of naked singularities in the spherically symmetric, plane symmetric and cylindrically symmetric collapse of charged null fluid in an anti-de Sitter background. The naked singularities are found to be strong in Tipler's sense and thus violate the cosmic censorship conjecture, but not hoop conjecture.
D-dimensional charged Anti-de-Sitter black holes in f ( T) gravity
Awad, A. M.; Capozziello, S.; Nashed, G. G. L.
2017-07-01
We present a D-dimensional charged Anti-de-Sitter black hole solutions in f ( T) gravity, where f ( T) = T + βT 2 and D ≥ 4. These solutions are characterized by flat or cylindrical horizons. The interesting feature of these solutions is the existence of inseparable electric monopole and quadrupole terms in the potential which share related momenta, in contrast with most of the known charged black hole solutions in General Relativity and its extensions. Furthermore, these solutions have curvature singularities which are milder than those of the known charged black hole solutions in General Relativity and Teleparallel Gravity. This feature can be shown by calculating some invariants of curvature and torsion tensors. Furthermore, we calculate the total energy of these black holes using the energy-momentum tensor. Finally, we show that these charged black hole solutions violate the first law of thermodynamics in agreement with previous results.
Nonlinear Evolution and Final Fate of Charged Anti-de Sitter Black Hole Superradiant Instability.
Bosch, Pablo; Green, Stephen R; Lehner, Luis
2016-04-08
We describe the full nonlinear development of the superradiant instability for a charged massless scalar field coupled to general relativity and electromagnetism, in the vicinity of a Reissner-Nordström-anti-de Sitter black hole. The presence of the negative cosmological constant provides a natural context for considering perfectly reflecting boundary conditions and studying the dynamics as the scalar field interacts repeatedly with the black hole. At early times, small superradiant perturbations grow as expected from linearized studies. Backreaction then causes the black hole to lose charge and mass until the perturbation becomes nonsuperradiant, with the final state described by a stable hairy black hole. For large gauge coupling, the instability extracts a large amount of charge per unit mass, resulting in greater entropy increase. We discuss the implications of the observed behavior for the general problem of superradiance in black hole spacetimes.
Charged de Sitter-like black holes: quintessence-dependent enthalpy and new extreme solutions
Energy Technology Data Exchange (ETDEWEB)
Azreg-Ainou, Mustapha [Baskent University, Faculty of Engineering, Ankara (Turkey)
2015-01-01
We consider Reissner-Nordstroem black holes surrounded by quintessence where both a non-extremal event horizon and a cosmological horizon exist besides an inner horizon (-1 ≤ ω < -1/3). We determine new extreme black hole solutions that generalize the Nariai horizon to asymptotically de Sitter-like solutions for any order relation between the squares of the charge q{sup 2} and the mass parameter M{sup 2} provided q{sup 2} remains smaller than some limit, which is larger than M{sup 2}. In the limit case q{sup 2} = 9ω{sup 2}M{sup 2}/(9ω{sup 2}-1), we derive the general expression of the extreme cosmo-blackhole, where the three horizons merge, and we discuss some of its properties.We also show that the endpoint of the evaporation process is independent of any order relation between q{sup 2} and M{sup 2}. The Teitelboim energy and the Padmanabhan energy are related by a nonlinear expression and are shown to correspond to different ensembles. We also determine the enthalpy H of the event horizon, as well as the effective thermodynamic volume which is the conjugate variable of the negative quintessential pressure, and show that in general the mass parameter and the Teitelboim energy are different from the enthalpy and internal energy; only in the cosmological case, that is, for Reissner-Nordstroem-de Sitter black hole we have H = M. Generalized Smarr formulas are also derived. It is concluded that the internal energy has a universal expression for all static charged black holes, with possibly a variable mass parameter, but it is not a suitable thermodynamic potential for static-black-hole thermodynamics if M is constant. It is also shown that the reverse isoperimetric inequality holds. We generalize the results to the case of the Reissner-Nordstroem-de Sitter black hole surrounded by quintessence with two physical constants yielding two thermodynamic volumes. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Rahaman, Farook; Bhar, Piyali [Jadavpur University, Department of Mathematics, Kolkata, West Bengal (India); Sharma, Ranjan [P. D. Women' s College, Department of Physics, Jalpaiguri (India); Tiwari, Rishi Kumar [Govt. Model Science College, Department of Mathematics, Rewa, MP (India)
2015-03-01
We report a 3-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. (orig.)
Regular black holes: Electrically charged solutions, Reissner-Nordstr\\"om outside a de Sitter core
Lemos, José P S
2011-01-01
To have the correct picture of a black hole as a whole it is of crucial importance to understand its interior. The singularities that lurk inside the horizon of the usual Kerr-Newman family of black hole solutions signal an endpoint to the physical laws and as such should be substituted in one way or another. A proposal that has been around for sometime, is to replace the singular region of the spacetime by a region containing some form of matter or false vacuum configuration that can also cohabit with the black hole interior. Black holes without singularities are called regular black holes. In the present work regular black hole solutions are found within general relativity coupled to Maxwell's electromagnetism and charged matter. We show that there are objects which correspond to regular charged black holes, whose interior region is de Sitter, whose exterior region is Reissner-Nordstr\\"om, and the boundary between both regions is made of an electrically charged spherically symmetric coat. There are several ...
Prasia, P
2016-01-01
In this work we study the Quasi Normal Modes(QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter((A)dS) space time. It is found that the behavior of QNMs changes with the massive parameter and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter and also on the charge of the black hole.
Energy Technology Data Exchange (ETDEWEB)
Blaga, Robert, E-mail: robert.blaga90@e-uvt.ro [Faculty of Physics, West University of Timişoara V. Pârvan Ave. 4, RO-300223 Timişoara (Romania)
2015-12-07
We investigate the energy radiated by an inertial scalar charge evolving in the expanding Poincaré patch of de Sitter spacetime, in the framework of scalar QED perturbation theory. We approximate the transition amplitude in the small expansion parameter limit and show that the leading contribution to the radiated energy has the form of the energy radiated by an accelerated particle in Minkowski space.
Charged de Sitter-like black holes: quintessence-dependent enthalpy and new extreme solutions
Azreg-Aïnou, Mustapha
2014-01-01
We consider Reissner-Nordstr\\"om black holes surrounded by quintessence where both a non-extremal event horizon and a cosmological horizon exist besides an inner horizon ($-1\\leq \\om <-1/3$). We determine new extreme black hole solutions that generalize the Nariai horizon to asymptotically de Sitter-like solutions for any order relation between the squares of the charge $q^2$ and the mass parameter $M^2$ provided $q^2$ remains smaller than some limit, which is larger than $M^2$. In the limit case $q^2=9\\om^2 M^2/(9\\om^2-1)$, we derive the general expression of the extreme cosmo-black-hole, where the three horizons merge, and discuss some of its properties. We also show that the endpoint of the evaporation process is independent of any order relation between $q^2$ and $M^2$. The Teitelboim's energy and Padmanabhan's energy are related by a nonlinear expression and are shown to correspond to different ensembles. We also determine the enthalpy $H$ of the event horizon, as well as the effective thermodynamic v...
Institute of Scientific and Technical Information of China (English)
XU Dian-Yah
2000-01-01
Absorbing charged rotating (ACR) metric in de Sitter space and related energy-momentum tensor are derived.The ACR metric is very simple in advanced time coordinates. The ACR metric involves 8 independent parameters which are divided into two classes: (1) the mass M, charge Q, angular momentum per unit mass a, and cosmological constant A; (2) M/ v, 2M/ v2, Q/ v, and 2Q/ v2. The non-stationary part of the energy-momentum tensor is positive definite everywhere.
Energy Technology Data Exchange (ETDEWEB)
Prasia, P.; Kuriakose, V.C. [Cochin University of Science and Technology, Department of Physics, Kochi (India)
2017-01-15
In this work we study the Quasi-Normal Modes (QNMs) under massless scalar perturbations and the thermodynamics of linearly charged BTZ black holes in massive gravity in the (Anti)de Sitter ((A)dS) space-time. It is found that the behavior of QNMs changes with the massive parameter of the graviton and also with the charge of the black hole. The thermodynamics of such black holes in the (A)dS space-time is also analyzed in detail. The behavior of specific heat with temperature for such black holes gives an indication of a phase transition that depends on the massive parameter of the graviton and also on the charge of the black hole. (orig.)
Applications of gauge/gravity dualities with charged Anti-de Sitter black holes
Energy Technology Data Exchange (ETDEWEB)
Grass, Viviane Theresa
2010-05-17
In this thesis, we deal with different applications of the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence. The AdS/CFT correspondence, which is also more generally referred to as gauge/gravity duality, is a conjectured duality in superstring theory between strongly-coupled four-dimensional N=4 superconformal Yang-Mills theory and weakly-coupled type IIB string theory in five-dimensional AdS spacetime. This duality provides a powerful method to investigate strongly-coupled low-energy systems in four dimensions by substitutionally carrying out calculations in five-dimensional weakly-coupled supergravity. In this work, we use the AdS/CFT correspondence to explore three different strongly-coupled systems, namely a brane world accommodating a strongly-coupled field theory, a strongly-coupled fluid on a three-sphere and a strongly-coupled p-wave superfluid. In all these cases, the dual supergravity descriptions involve charged AdS black holes. The first system studied here is a Randall-Sundrum brane world moving in the background of a five-dimensional non-extremal black hole of N=2 gauged supergravity. The equations of motion of the brane are found to be equal to the Friedmann-Robertson-Walker (FRW) equations for a closed universe. The closed brane universe has special thermodynamic properties. The energy of the brane field theory exhibits a subextensive Casimir contribution, and the entropy can be expressed as a Cardy-Verlinde-type formula. We show that the equations for both quantities can take forms that strongly resemble the two FRW equations. At the horizon of the black hole, these two sets of equations are shown to even merge with each other which might suggest the existence of a common underlying theory. In addition, as a by-product result, the non-extremal black hole solutions considered here are found to admit an alternative description in terms of first-order flow equations similar to those which are well-known from the attractor mechanism of
Daudé, Thierry
2017-01-01
In this paper, the authors study the direct and inverse scattering theory at fixed energy for massless charged Dirac fields evolving in the exterior region of a Kerr-Newman-de Sitter black hole. In the first part, they establish the existence and asymptotic completeness of time-dependent wave operators associated to our Dirac fields. This leads to the definition of the time-dependent scattering operator that encodes the far-field behavior (with respect to a stationary observer) in the asymptotic regions of the black hole: the event and cosmological horizons. The authors also use the miraculous property (quoting Chandrasekhar)-that the Dirac equation can be separated into radial and angular ordinary differential equations-to make the link between the time-dependent scattering operator and its stationary counterpart. This leads to a nice expression of the scattering matrix at fixed energy in terms of stationary solutions of the system of separated equations. In a second part, the authors use this expression of ...
Instability of Charged Gauss-Bonnet Black Hole in de Sitter Spacetime at Large $D$
Chen, Bin
2016-01-01
We study the stabilities of (A)dS charged Gauss-Bonnet(GB) black holes in the large $D$ dimensions. After integrating the equation of motion with respect to the radial direction, we obtain the effective equations at large $D$ to describe the nonlinear dynamical deformations of the black hole. From the perturbation analysis of the effective equations, we get the analytic expressions of the frequencies for the quasinormal modes of scalar type. Furthermore we show that the charged GB black hole becomes unstable only if the cosmological constant is positive, otherwise the black hole is always stable. At the onset of instabilities there is a non-trivial static zero-mode perturbation, which suggests the existence of a new non-spherical symmetric solution branch of static dS charged GB black holes. We construct the non-spherical symmetric static solution of the large $D$ effective equations explicitly.
Institute of Scientific and Technical Information of China (English)
YANG Shu-Zheng; JIANG Qing-Quan; LI Hui-Ling
2006-01-01
Applying Parikh-Wilzcek's semi-classical quantum tunneling model, we study the Hawking radiation of charged particles as tunneling from the event horizon of a cylindrically symmetric black hole in anti-de Sitter space-time.The derived result shows that the tunneling rate of charged particles is related to the change of Bekenstein-Hawking entropy and that the radiation spectrum is not strictly pure thermal after taking the black hole background dynamical and self-gravitation interaction into account, but is consistent with the underlying unitary theory.
Conserved Charges and First Law of Thermodynamics for Kerr-de Sitter Black Holes
Hajian, Kamal
2016-01-01
Recently, a general formulation for calculating conserved charges for (black hole) solutions to generally covariant gravitational theories, in any dimensions and with arbitrary asymptotic behaviors has been introduced. Equipped with this method, which can be dubbed as "solution phase space method," we calculate mass and angular momentum for the Kerr-dS black hole. Then, for any choice of horizons, associated entropy and the first law of thermodynamics are derived. Interestingly, according to insensitivity of the analysis to the chosen cosmological constant, the analysis unifies the thermodynamics of rotating stationary black holes in 4 (and other) dimensions with either AdS, flat or dS asymptotics. We extend the analysis to include electric charge, i.e. to the Kerr-Newman-dS black hole.
Charged Rotating Black Branes in anti-de Sitter Einstein-Gauss-Bonnet Gravity
Dehghani, M H
2003-01-01
We present a new class of charged rotating solutions in the Einstein-Gauss-Bonnet gravity with a negative cosmological constant. These solutions may be interpreted as black brane solutions with two inner and outer event horizons or an extreme black brane depending on the value of the mass parameter $m$. We also find that the Killing vectors are the null generators of the event horizon. The physical properties of the brane such as the temperature, the angular velocity, the entropy, the electric charge and potential are computed. We also compute the action and the Gibbs potential as a function of temperature and angular velocity for the uncharged solutions, and compute the angular momentum and the mass of the black brane through the use of Gibbs potential. We show that these thermodynamic quantities satisfy the first law of thermodynamics. We also perform a local stability analysis of the asymptotically AdS uncharged rotating black brane in various dimensions and show that they are locally stable for the whole ...
Graviatoms with de Sitter Interior
Directory of Open Access Journals (Sweden)
Irina Dymnikova
2013-01-01
Full Text Available We present a graviatom with de Sitter interior as a new candidate to atomic dark matter generically related to a vacuum dark energy through its de Sitter vacuum interior. It is a gravitationally bound quantum system consisting of a nucleus represented by a regular primordial black hole (RPBH, its remnant or gravitational vacuum soliton G-lump, and a charged particle. We estimate probability of formation of RPBHs and G-lumps in the early Universe and evaluate energy spectrum and electromagnetic radiation of graviatom which can in principle bear information about a fundamental symmetry scale responsible for de Sitter interior and serve as its observational signatures.
Brihaye, Y
2011-01-01
We study the stability of static as well as of rotating and charged black holes in (4+1)-dimensional Anti-de Sitter space-time which possess spherical horizon topology. We observe a non-linear instability related to the condensation of a charged, tachyonic scalar field and construct "hairy" black hole solutions of the full system of coupled Einstein, Maxwell and scalar field equations. We observe that the limiting solution for small horizon radius is either a hairy soliton solution or a singular solution that is not a regular extremal solution. Within the context of the gauge/gravity duality the condensation of the scalar field describes a holographic conductor/superconductor phase transition on the surface of a sphere.
Rahaman, Farook; Sharma, Ranjan; Tiwari, Rishi Kumar
2014-01-01
We report a 3D charged black hole solution in an anti desetter space inspired by noncommutative geometry.In this construction,the black hole exhibits two horizon which turn into a single horizon in the extreme case.We investigate the impacts of the 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.
Burrage, Clare; Heisenberg, Lavinia
2011-01-01
We generalize the Galileon symmetry and its relativistic extension to a de Sitter background. This is made possible by studying a probe-brane in a flat five-dimensional bulk using a de Sitter slicing. The generalized Lovelock invariants induced on the probe brane enjoy the induced Poincar\\'e symmetry inherited from the bulk, while living on a de Sitter geometry. The non-relativistic limit of these invariants naturally maintain a generalized Galileon symmetry around de Sitter while being free of ghost-like pathologies. We comment briefly on the cosmology of these models and the extension to the AdS symmetry as well as generic FRW backgrounds.
Burrage, Clare; de Rham, Claudia; Heisenberg, Lavinia
2011-05-01
We generalize the Galileon symmetry and its relativistic extension to a de Sitter background. This is made possible by studying a probe-brane in a flat five-dimensional bulk using a de Sitter slicing. The generalized Lovelock invariants induced on the probe brane enjoy the induced Poincaré symmetry inherited from the bulk, while living on a de Sitter geometry. The non-relativistic limit of these invariants naturally maintain a generalized Galileon symmetry around de Sitter while being free of ghost-like pathologies. We comment briefly on the cosmology of these models and the extension to the AdS symmetry as well as generic FRW backgrounds.
Micromanaging de Sitter holography
Dong, Xi; Silverstein, Eva; Torroba, Gonzalo
2010-01-01
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.
De Sitter projective relativity
Licata, Ignazio; Benedetto, Elmo
2017-01-01
This book presents the Projective approach to de Sitter Relativity. It traces the development of renewed interest in models of the universe at constant positive curvature such as "vacuum" geometry. The De Sitter Theory of Relativity, formulated in 1917 with Willem De Sitter's solution of the Einstein equations, was used in different fields during the 1950s and 1960s, in the work of H. Bacry, J.M. LevyLeblond and F.Gursey, to name some important contributors. From the 1960s to 1980s, L. Fantappié and G. Arcidiacono provided an elegant group approach to the De Sitter universe putting the basis for special and general projective relativity. Today such suggestions flow into a unitary scenario, and this way the De Sitter Relativity is no more a "missing opportunity" (F. Dyson, 1972), but has a central role in theoretical physics. In this volume a systematic presentation is given of the De Sitter Projective relativity, with the recent developments in projective general relativity and quantum cosmology.
Bergshoeff, Eric A; Kallosh, Renata; Van Proeyen, Antoine
2015-01-01
Using superconformal methods we derive an explicit de Sitter supergravity action invariant under spontaneously broken local ${\\cal N}=1$ supersymmetry. The supergravity multiplet interacts with a nilpotent goldstino multiplet. We present a complete locally supersymmetric action including the graviton and the fermionic fields, gravitino and goldstino, no scalars. In the global limit when supergravity multiplet decouples, our action reproduces the Volkov-Akulov theory. In the unitary gauge where goldstino vanishes we recover pure supergravity with the positive cosmological constant. The classical equations of motion, with all fermions vanishing, have a maximally symmetric solution: de Sitter space.
Polyakov, A. M.
2008-07-01
This paper explores infrared quantum effects in the de Sitter space. The notion of "eternal manifolds" is introduced and it is shown that in most cases the de Sitter space does not belong to this class. It is unstable under small perturbations which may cause a breakdown of the de Sitter symmetry. The de Sitter string sigma model is discussed. It is argued that the gauge theory at the complex coupling is dual to the matrix elements of vertex operators in the de Sitter space, taken between the Bunch-Davies vacuum and the "out" state without particles. The described infrared effects are likely to screen away the cosmological constant.
On higher spin symmetries in de Sitter QFTs
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.
On higher spin symmetries in de Sitter QFTs
Costa, Renato
2015-01-01
We consider the consequences of global higher-spin symmetries in quantum field theories on a fixed de Sitter background of spacetime dimension $D \\ge 3$. 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.
On higher spin symmetries in de Sitter QFTs
Energy Technology Data Exchange (ETDEWEB)
Costa, Renato [Instituto de Física Teorica, UNESP-Universidade Estadual Paulista,R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Department of Physics, McGill University,3600 rue University, Montréal, QC H3A 2T8 (Canada); Morrison, Ian A. [Department of Physics, McGill University,3600 rue University, Montréal, QC H3A 2T8 (Canada)
2016-03-10
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.
Albrecht, Andreas; Richard, Benoit J
2014-01-01
We address the following question: To what extent can a quantum field tell if it has been placed in de Sitter space? Our approach is to use the techniques of non-equilibrium quantum field theory to compute the time evolution of a state which starts off in flat space for (conformal) times $\\eta<\\eta_0$, and then evolves in a de Sitter background turned on instantaneously at $\\eta=\\eta_0$. We find that the answer depends on what quantities one examines. We study a range of them, all based on two-point correlation functions, and analyze which ones approach the standard Bunch-Davies values over time. The outcome of this analysis suggests that the nature of the equilibration process in this system is similar to that in more familiar systems.
de Sitter Supersymmetry Revisited
Anous, Tarek; Maloney, Alexander
2014-01-01
We present the basic $\\mathcal{N} =1$ superconformal field theories in four-dimensional de Sitter space-time, namely the non-abelian super Yang-Mills theory and the chiral multiplet theory with gauge interactions or cubic superpotential. These theories have eight supercharges and are invariant under the full $SO(4,2)$ group of conformal symmetries, which includes the de Sitter isometry group $SO(4,1)$ as a subgroup. The theories are ghost-free and the anti-commutator $\\sum_\\alpha\\{Q_\\alpha, Q^{\\alpha\\dagger}\\}$ is positive. SUSY Ward identities uniquely select the Bunch-Davies vacuum state. This vacuum state is invariant under superconformal transformations, despite the fact that de Sitter space has non-zero Hawking temperature. The $\\mathcal{N}=1$ theories are classically invariant under the $SU(2,2|1)$ superconformal group, but this symmetry is broken by radiative corrections. However, no such difficulty is expected in the $\\mathcal{N}=4$ theory, which is presented in appendix B.
Fluctuation and dissipation in de Sitter space
Fischler, Willy; Pedraza, Juan F; Tangarife, Walter
2014-01-01
In this paper we study some thermal properties of quantum field theories in de Sitter space by means of holographic techniques. We focus on the static patch of de Sitter and assume that the quantum fields are in the standard Bunch-Davies vacuum. More specifically, we follow the stochastic motion of a massive charged particle due to its interaction with Hawking radiation. The process is described in terms of the theory of Brownian motion in inhomogeneous media and its associated Langevin dynamics. At late times, we find that the particle undergoes a regime of slow diffusion and never reaches the horizon, in stark contrast to the usual random walk behavior at finite temperature. Nevertheless, the fluctuation-dissipation theorem is found to hold at all times.
Reynolds, Alan P.; Ross, Simon F.
2017-09-01
We consider the holographic complexity conjectures for de-Sitter invariant states in a quantum field theory on de Sitter space, dual to asymptotically anti-de Sitter geometries with de Sitter boundaries. The bulk holographic duals include solutions with or without a horizon. If we compute the complexity from the spatial volume, we find results consistent with general expectations, but the conjectured bound on the growth rate is not saturated. If we compute complexity from the action of the Wheeler–de Witt patch, we find qualitative differences from the volume calculation, with states of smaller energy having larger complexity than those of larger energy, even though the latter have bulk horizons.
Schwinger effect in de Sitter space
Fröb, Markus B; Kanno, Sugumi; Sasaki, Misao; Soda, Jiro; Tanaka, Takahiro; Vilenkin, Alexander
2014-01-01
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 $m^2\\gg eE,H^2$, 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 \\ll H$ lead to a phenomenon of infrared hyperconductivity, where a very small electric field $mH \\lesssim eE \\ll H^2$ leads to a...
Energy Technology Data Exchange (ETDEWEB)
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.
Narayan, K
2015-01-01
We study extremal surfaces in de Sitter space in the Poincare slicing in the upper patch, anchored on spatial subregions at the future boundary ${\\cal I}^+$, restricted to constant boundary Euclidean time slices (focussing on strip subregions). We find real extremal surfaces of minimal area as the boundaries of past lightcone wedges of the subregions in question: these are null surfaces with vanishing area. We find also complex extremal surfaces as complex extrema of the area functional, and the area is not always real-valued. In $dS_4$ the area is real and has some structural resemblance with entanglement entropy in a dual $CFT_3$. There are parallels with analytic continuation from the Ryu-Takayanagi expressions for holographic entanglement entropy in $AdS$. We also discuss extremal surfaces in the $dS$ black brane and the de Sitter "bluewall" studied previously. The $dS_4$ black brane complex surfaces exhibit a real finite cutoff-independent extensive piece. In the bluewall geometry, there are real surface...
de Sitter entropy from conformal field theory
Kabat, D; Kabat, Daniel; Lifschytz, Gilad
2002-01-01
We propose that the entropy of de Sitter space can be identified with the mutual entropy of a dual conformal field theory. We argue that unitary time evolution in de Sitter space restricts the total number of excited degrees of freedom to be bounded by the de Sitter entropy, and we give a CFT interpretation of this restriction. We also clarify issues arising from the fact that both de Sitter and anti de Sitter have dual descriptions in terms of conformal field theory.
Maltz, Jonathan
2016-01-01
A quantum mechanical formulation of de Sitter cosmological spacetimes still eludes string theory. In this paper we conjecture a potentially rigorous framework in which the status of de Sitter space is the same as that of a resonance in a scattering process. We conjecture that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant poles characteristic meta-stable intermediate states. A calculation employing constrained instantons illustrates this idea.
Castro, Alejandra; Lashkari, Nima; Maloney, Alexander
2011-01-01
We consider quantum Einstein gravity in three dimensional de Sitter space. The Euclidean path integral is formulated as a sum over geometries, including both perturbative loop corrections and non-perturbative instanton corrections coming from geometries with non-trivial topology. These non-trivial geometries have a natural physical interpretation. Conventional wisdom states that the sphere is the unique Euclidean continuation of de Sitter space. However, when considering physics only in the c...
On electric field in anti-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Cheong, Lee Yen, E-mail: lee-yencheong@petronas.com.my, E-mail: chewxy01813@gmail.com, E-mail: dennis.ling@petronas.com.my; Yan, Chew Xiao, E-mail: lee-yencheong@petronas.com.my, E-mail: chewxy01813@gmail.com, E-mail: dennis.ling@petronas.com.my; Ching, Dennis Ling Chuan, E-mail: lee-yencheong@petronas.com.my, E-mail: chewxy01813@gmail.com, E-mail: dennis.ling@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, Bandar Seri Iskandar, Tronoh 31750, Perak (Malaysia)
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.
Conformal use of retarded Green's functions for the Maxwell field in de Sitter space
Faci, S; Renaud, J
2011-01-01
We propose a new propagation formula for the Maxwell field in de Sitter space which exploit the conformal invariance of this field together with a conformal gauge condition. This formula allows to determine the classical electromagnetic field in the de Sitter space from given currents and initial data. It only uses the Green's function of the massless Minkowskian scalar field. This leads to drastic simplifications in practical calculations. We apply this formula to the classical problem of the two charges of opposite signs at rest at the North and South Poles of the de Sitter space.
Quantum Field Theory in de Sitter spacetime
So, Ashaq Hussain; Sibuea, Marlina Rosalinda; Akhoon, Shabir Ahmad; Khanday, Bilal Nisar; Majeed, Sajad Ul; Rather, Asloob Ahmad; Nahvi, Ishaq
2013-01-01
In this paper we will analyse quantum ?eld theory on de Sitter space- time. We will ?rst analyse a general scalar and vector ?eld theory on de Sitter spacetime. This is done by ?rst calculating these propagators on four-Sphere and then analytically continuing it to de Sitter spacetime.
Renormalised fermion vacuum expectation values on anti-de Sitter space–time
Energy Technology Data Exchange (ETDEWEB)
Ambruș, Victor E., E-mail: Victor.Ambrus@gmail.com [Center for Fundamental and Advanced Technical Research, Romanian Academy, Bd. Mihai Viteazul 24, Timișoara 300223 (Romania); Winstanley, Elizabeth, E-mail: E.Winstanley@sheffield.ac.uk [Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)
2015-10-07
The Schwinger–de Witt and Hadamard methods are used to obtain renormalised vacuum expectation values for the fermion condensate, charge current and stress-energy tensor of a quantum fermion field of arbitrary mass on four-dimensional anti-de Sitter space–time. The quantum field is in the global anti-de Sitter vacuum state. The results are compared with those obtained using the Pauli–Villars and zeta-function regularisation methods, respectively.
Renormalised fermion vacuum expectation values on anti-de Sitter space–time
Directory of Open Access Journals (Sweden)
Victor E. Ambruș
2015-10-01
Full Text Available The Schwinger–de Witt and Hadamard methods are used to obtain renormalised vacuum expectation values for the fermion condensate, charge current and stress-energy tensor of a quantum fermion field of arbitrary mass on four-dimensional anti-de Sitter space–time. The quantum field is in the global anti-de Sitter vacuum state. The results are compared with those obtained using the Pauli–Villars and zeta-function regularisation methods, respectively.
Born-Infeld-de Sitter gravity: Cold, ultracold and Nariai black holes
Fernando, Sharmanthie
2013-01-01
In this paper, we have presented interesting properties of the static charged Born-Infeld-de Sitter black hole. They can have time-like as well as space-like singularities depending on the parameters of the theory. The degenerate black holes lead to cold, ultra cold and Nariai black holes. The geometry of such black holes are discussed. A comparison is done with the Reissner-Nordstrom-de Sitter black holes.
Superradiant instabilities of asymptotically anti-de Sitter black holes
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.
Accelerating in de Sitter spacetimes
Cotaescu, Ion I
2014-01-01
We propose a definition of uniform accelerated frames in de Sitter spacetimes exploiting the Nachtmann group theoretical method of introducing coordinates on these manifolds. Requiring the transformation between the static frame and the accelerated one to depend continuously on acceleration in order to recover the well-known Rindler approach in the flat limit, we obtain a result with a reasonable physical meaning.
Quantum Larmor radiation in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Blaga, Robert; Busuioc, Sergiu [West University of Timisoara, Timisoara (Romania)
2016-09-15
We study the radiation emitted by inertial charge evolving on the expanding de Sitter spacetime. Performing a perturbative calculation, within scalar quantum electrodynamics (sQED), we obtain the transition amplitude for the process and using this we define the energy radiated by the source. In the non-relativistic limit we find that the leading term is compatible with the classical result (Larmor formula). The first quantum correction is found to be negative, a result which is in line with a number of similar quantum field theory results. For the ultra-relativistic case we find a logarithmic divergence of the emitted energy for large frequencies, which we link to the nature of the spacetime. We compare our results with that of Nomura et al. (JCAP 11:013, 2006), where the authors make a similar calculation for a general conformally flat spacetime. (orig.)
Fernando, Sharmanthie
2016-01-01
In this paper we present a regular black hole with a positive cosmological constant. The regular black hole considered is the well known Bardeen black hole and it is a solution to the Einstein equations coupled to non-linear electrodynamics with a magnetic monopole. The paper discuss the properties of the Bardeen-de Sitter black hole. We have computed the grey body factors and partial absorption cross sections for massless scalar field impinges on this black hole with the third order WKB approximation. A detailed discussion on how the behavior of the grey body factors depend on the parameters of the theory such as the mass, charge and the cosmological constant is given. Possible extensions of the work is discussed at the end of the paper.
Asymptotic Symmetries in de Sitter and Inflationary Spacetimes
Ferreira, Ricardo Z; Sloth, Martin S
2016-01-01
Soft gravitons produced by the expansion of de Sitter can be viewed as the Nambu-Goldstone bosons of spontaneously broken asymptotic symmetries of the de Sitter spacetime. We explicitly construct the associated charges, and show that acting with the charges on the vacuum creates a new state equivalent to a change in the local coordinates induced by the soft graviton. While the effect remains unobservable within the domain of a single observer where the symmetry is unbroken, this change is physical when comparing different asymptotic observers, or between a transformed and un-transformed initial state, consistent with the scale-dependent statistical anisotropies previously derived using semiclassical relations. We then compute the overlap, $\\langle0| 0'\\rangle$, between the unperturbed de Sitter vacuum $|0\\rangle$, and the state $| 0'\\rangle$ obtained by acting $\\mathcal{N}$ times with the charge. We show that when $\\mathcal{N}\\to M_p^2/H^2$ this overlap receives order one corrections and $\\langle0| 0'\\rangle\\...
Inflation and de Sitter Thermodynamics
Frolov, A; Frolov, Andrei; Kofman, Lev
2003-01-01
We consider the quasi-de Sitter geometry of the inflationary universe. We calculate the energy flux of the slowly rolling background scalar field through the quasi-de Sitter apparent horizon and set it equal to the change of the entropy (1/4 of the area) multiplied by the temperature, dE=TdS. Remarkably, this thermodynamic law reproduces the Friedmann equation for the rolling scalar field. The flux of the slowly rolling field through the horizon of the quasi-de Sitter geometry is similar to the accretion of a rolling scalar field onto a black hole, which we also analyze. Next we add inflaton fluctuations which generate scalar metric perturbations. Metric perturbations result in a variation of the area entropy. Again, the equation dE=TdS with fluctuations reproduces the linearized Einstein equations. In this picture as long as the Einstein equations hold, holography does not put limits on the quantum field theory during inflation. Due to the accumulating metric perturbations, the horizon area during inflation ...
Hamiltonian Formalism of de-Sitter Invariant Special Relativity
Institute of Scientific and Technical Information of China (English)
YAN Mu-Lin; XIAO Neng-Chao; HUANG Wei; LI Si
2007-01-01
The Lagrangian of Einstein's special relativity with universal parameter c (SRc) is invariant under Poincaré transformation, which preserves Lorentz metric ημν. The SRc has been extended to be one which is invariant under de Sitter transformation that preserves so-called Beltrami metric Bμν. There are two universal parameters, c and R, in this Special Relativity (denoted as SRcR). The Lagrangian-Hamiltonian formulism of SRcR is formulated in this paper.The canonic energy, canonic momenta, and 10 Noether charges corresponding to the space-time's de Sitter symmetry are derived. The canonical quantization of the mechanics for SRcR-free particle is performed. The physics related to it is discussed.
Hamiltonian Formalism of de-Sitter Invariant Special Relativity
Yan, Mu-Lin; Xiao, Neng-Chao; Huang, Wei; Li, Si
2007-07-01
The Lagrangian of Einstein's special relativity with universal parameter c (Script SRc) is invariant under Poincaré transformation, which preserves Lorentz metric ημν. The Script SRc has been extended to be one which is invariant under de Sitter transformation that preserves so-called Beltrami metric Bμν. There are two universal parameters, c and R, in this Special Relativity (denoted as Script SRcR). The Lagrangian-Hamiltonian formulism of Script SRcR is formulated in this paper. The canonic energy, canonic momenta, and 10 Noether charges corresponding to the space-time's de Sitter symmetry are derived. The canonical quantization of the mechanics for Script SRcR-free particle is performed. The physics related to it is discussed.
Noncommutative de Sitter and FRW spaces
Energy Technology Data Exchange (ETDEWEB)
Buric, Maja [University of Belgrade, Faculty of Physics, P.O. Box 44, Belgrade (Serbia); Madore, John [Laboratoire de Physique Theorique, Orsay (France)
2015-10-15
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. (orig.)
Spacetime Dimensionality from de Sitter Entropy
Momen, Arshad
2011-01-01
We argue that the spontaneous creation of de Sitter universes favors three spatial dimensions. The conclusion relies on the causal-patch description of de Sitter space, where fiducial observers experience local thermal equilibrium up to a stretched horizon, on the holographic principle, and on some assumptions about the nature of gravity and the constituents of Hawking/Unruh radiation.
Noncommutative de Sitter and FRW spaces
Energy Technology Data Exchange (ETDEWEB)
Burić, Maja, E-mail: majab@ipb.ac.rs [Faculty of Physics, University of Belgrade, P.O. Box 44, 11001, Belgrade (Serbia); Madore, John, E-mail: madore@th.u-psud.fr [Laboratoire de Physique Théorique, 91405, Orsay (France)
2015-10-24
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.
De Sitter Symmetry and Quantum Theory
Lev, Felix M
2011-01-01
De Sitter symmetry on quantum level implies that operators describing a given system satisfy commutation relations of the de Sitter algebra. This approach gives a new perspective on fundamental notions of quantum theory. We discuss applications of the approach to the cosmological constant problem, gravity and particle theory.
Noncommutative de Sitter and FRW spaces
Buric, Maja
2015-01-01
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.
Twistors and antipodes in de Sitter space
Neiman, Yasha
2014-03-01
We develop the basics of twistor theory in de Sitter space, up to the Penrose transform for free massless fields. We treat de Sitter space as fundamental, as one does for Minkowski space in conventional introductions to twistor theory. This involves viewing twistors as spinors of the de Sitter group SO(4,1). When attached to a spacetime point, such a twistor can be reinterpreted as a local SO(3,1) Dirac spinor. Our approach highlights the antipodal map in de Sitter space, which gives rise to doublings in the standard relations between twistors and spacetime. In particular, one can generate a field with both handedness signs from a single twistor function. Such fields naturally live on antipodally identified de Sitter space dS4/Z2, which has been put forward as the ideal laboratory for quantum gravity with a positive cosmological constant.
Entropy in locally-de Sitter spacetimes
Araujo, A
2015-01-01
As quotient spaces, Minkowski and de Sitter are fundamental spacetimes in the sense that they are known "a priori", independently of Einstein equation. They represent different non-gravitational backgrounds for the construction of physical theories. If general relativity is constructed on a de Sitter spacetime, the underlying kinematics will no longer be ruled by Poincar\\'e, but by the de Sitter group. In this case the definition of diffeomorphism changes, producing concomitant changes in the notions of energy and entropy. These changes are explicitly discussed for the case of the Schwarzschild solution, in which the black hole and the de Sitter horizons show up as a unique entangled system. Such entanglement, together with energy conservation, create a constraint between the black hole activity and the evolution of the de Sitter radius, providing a new scenario for the study of cosmology.
Building an explicit de Sitter
Energy Technology Data Exchange (ETDEWEB)
Louis, Jan [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Hamburg Univ. (Germany). Zentrum fuer Mathematische Physik; Rummel, Markus; Valandro, Roberto [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie
2012-11-15
We construct an explicit example of a de Sitter vacuum in type IIB string theory that realizes the proposal of Kaehler uplifting. As the large volume limit in this method depends on the rank of the largest condensing gauge group we carry out a scan of gauge group ranks over the Kreuzer-Skarke set of toric Calabi-Yau threefolds. We find large numbers of models with the largest gauge group factor easily exceeding a rank of one hundred. We construct a global model with Kaehler uplifting on a two-parameter model on CP{sup 4}{sub 11169}, by an explicit analysis from both the type IIB and F-theory point of view. The explicitness of the construction lies in the realization of a D7 brane configuration, gauge flux and RR and NS flux choices, such that all known consistency conditions are met and the geometric moduli are stabilized in a metastable de Sitter vacuum with spontaneous GUT scale supersymmetry breaking driven by an F-term of the Kaehler moduli.
Null geodesics in the Reissner-Nordstr\\"om Anti-de Sitter black holes
Cruz, Norman; Saavedra, Joel; Villanueva, J R
2011-01-01
In this work we address the study of null geodesics in the background of Reissner-Nordstr\\"om Anti de Sitter black holes. We compute the exact trajectories in terms of elliptic functions of Weierstrass, obtaining a detailed description of the orbits in terms of charge, mass and the cosmological constant. The trajectories of the photon are classified using the impact parameter.
Hopfing and Puffing Warped Anti-de Sitter Space
Anninos, Dionysios
2009-01-01
Three dimensional spacelike warped anti-de Sitter space is studied in the context of Einstein theories of gravity and string theory, where there is no gravitational Chern-Simons term in the action. We propose that it is holographically dual to a two-dimensional conformal field theory with equal left and right moving central charges. Various checks of the central charges are offered, based on the Bekenstein-Hawking entropy of the stretched warped black holes and warped self-dual solutions. The proposed central charges are applied to compute the Bekenstein-Hawking entropy of the Hopf T-dual of six-dimensional dyonic black strings which have a near horizon consisting of three dimensional warped anti-de Sitter space times a three-sphere. We find that the Hopf T-duality is a map between thermal states with equal entropy of the CFTs dual to the dyonic black string and the Hopf T-dualized black string.
Some geometry of de Sitter space
Tod, Paul
2015-01-01
In this expository note, I present some basic geometric and twistor theoretic facts about de Sitter space leading up to a discussion of Penrose's quasi-local mass construction for linear gravity theory in the de Sitter background. The corresponding results for Minkowski space and anti--de Sitter space are familiar and can be found in \\cite{PR} or \\cite{HT} for the former and \\cite{KT} for the latter. Some of the formulas given here are also quite familiar, but some are thought to be new and it is convenient to have these facts collected in one place.
Flux compactifications, gauge algebras and De Sitter
Energy Technology Data Exchange (ETDEWEB)
Dibitetto, Giuseppe, E-mail: g.dibitetto@rug.n [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands); Linares, Roman, E-mail: lirr@xanum.uam.m [Departamento de Fisica, Universidad Autonoma Metropolitana Iztapalapa, San Rafael Atlixco 186, C.P. 09340, Mexico D.F. (Mexico); Roest, Diederik, E-mail: d.roest@rug.n [Centre for Theoretical Physics, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)
2010-04-26
The introduction of (non-)geometric fluxes allows for N=1 moduli stabilisation in a De Sitter vacuum. The aim of this Letter is to assess to what extent this is true in N=4 compactifications. First we identify the correct gauge algebra in terms of gauge and (non-)geometric fluxes. We then show that this algebra does not lead to any of the known gaugings with De Sitter solutions. In particular, the gaugings that one obtains from flux compactifications involve non-semi-simple algebras, while the known gaugings with De Sitter solutions consist of direct products of (semi-)simple algebras.
More on the covariant retarded Green's function for the electromagnetic field in de Sitter spacetime
Higuchi, Atsushi; Nicholas, Jack R
2009-01-01
In a recent paper (Phys. Rev. D78, 084031 (2008), arXiv:0808.0642, Ref. [1]) it was shown in examples that the covariant retarded Green's functions in particular gauges for electromagnetism and linearized gravity can be used to reproduce field configurations correctly in spite of the spacelike nature of past infinity in de Sitter spacetime. In this paper we extend the work of Ref. [1] concerning the electromagnetic field and show that the covariant retarded Green's function with an arbitrary value of the gauge parameter reproduces the electromagnetic field from two opposite charges at antipodal points of de Sitter spacetime.
On supersymmetric Anti-de-Sitter, de-Sitter and Minkowski flux backgrounds
Gran, U; Papadopoulos, G
2016-01-01
We test the robustness of the conditions required for the existence of (supersymmetric) warped flux anti-de Sitter, de Sitter, and Minkowski backgrounds in supergravity theories using as examples suitable foliations of anti-de Sitter spaces. We find that there are supersymmetric de Sitter solutions in supergravity theories including maximally supersymmetric ones in 10- and 11-dimensional supergravities. Moreover, warped flux Minkowski backgrounds can admit Killing spinors which are not Killing on the Minkowski subspace and therefore cannot be put in a factorized form.
Interacting scalar fields in de Sitter space
Devaraj, G; Devaraj, Ganesh; Einhorn, Martin B
1995-01-01
We investigate the massless \\lambda \\phi^4 theory in de Sitter space. We argue that the infrared divergence associated with the free massless, minimally coupled scalar field in de Sitter space is not present when interactions are included because the field does not remain minimally coupled. This is essentially because \\xi=0 is not a fixed point of the renormalization group once interactions are included.
de Sitter Space as a Resonance
Maltz, Jonathan; Susskind, Leonard
2017-03-01
A quantum mechanical formulation of de Sitter cosmological spacetimes still eludes string theory. In this Letter we conjecture a potentially rigorous framework in which the status of de Sitter space is the same as that of a resonance in a scattering process. We conjecture that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant pole characteristic metastable intermediate states. A calculation employing constrained instantons illustrates this idea.
Quantum break-time of de Sitter
Dvali, Gia; Gómez, César; Zell, Sebastian
2017-06-01
The quantum break-time of a system is the time-scale after which its true quantum evolution departs from the classical mean field evolution. For capturing it, a quantum resolution of the classical background—e.g., in terms of a coherent state—is required. In this paper, we first consider a simple scalar model with anharmonic oscillations and derive its quantum break-time. Next, following [1], we apply these ideas to de Sitter space. We formulate a simple model of a spin-2 field, which for some time reproduces the de Sitter metric and simultaneously allows for its well-defined representation as quantum coherent state of gravitons. The mean occupation number N of background gravitons turns out to be equal to the de Sitter horizon area in Planck units, while their frequency is given by the de Sitter Hubble parameter. In the semi-classical limit, we show that the model reproduces all the known properties of de Sitter, such as the redshift of probe particles and thermal Gibbons-Hawking radiation, all in the language of quantum S-matrix scatterings and decays of coherent state gravitons. Most importantly, this framework allows to capture the 1/N-effects to which the usual semi-classical treatment is blind. They violate the de Sitter symmetry and lead to a finite quantum break-time of the de Sitter state equal to the de Sitter radius times N. We also point out that the quantum-break time is inversely proportional to the number of particle species in the theory. Thus, the quantum break-time imposes the following consistency condition: older and species-richer universes must have smaller cosmological constants. For the maximal, phenomenologically acceptable number of species, the observed cosmological constant would saturate this bound if our Universe were 10100 years old in its entire classical history.
Thermodynamic properties of Reissner-Nordstr(o)m-de Sitter quintessence black holes
Institute of Scientific and Technical Information of China (English)
Wei Yi-Huan; Ren Jun
2013-01-01
The mass,electric charge,and temperature of black holes in the Reissner-Nordstr(o)m-de Sitter quintessence (RN-dSQ) spacetime are obtained.The heat capacities of the RN-dSQ black holes for certain electric charges and masses are analyzed.The electrostatic energy and dark energy in the RN-dSQ black holes are also calculated.
Inflation as de Sitter instability
Energy Technology Data Exchange (ETDEWEB)
Cadoni, Mariano; Franzin, Edgardo [Universita di Cagliari, Cittadella Universitaria, Dipartimento di Fisica, Monserrato (Italy); INFN, Sezione di Cagliari, Monserrato (Italy); Mignemi, Salvatore [INFN, Sezione di Cagliari, Monserrato (Italy); Universita di Cagliari, Dipartimento di Matematica e Informatica, Cagliari (Italy)
2016-09-15
We consider cosmological inflation generated by a scalar field slowly rolling off from a de Sitter maximum of its potential. The models belong to the class of hilltop models and represent the most general model of this kind in which the scalar potential can be written as the sum of two exponentials. The minimally coupled Einstein-scalar gravity theory obtained in this way is the cosmological version of a two-scale generalization of known holographic models, allowing for solitonic solutions interpolating between an AdS spacetime in the infrared and scaling solutions in the ultraviolet. We then investigate cosmological inflation in the slow-roll approximation. Our model reproduces correctly, for a wide range of its parameters, the most recent experimental data for the power spectrum of primordial perturbations. Moreover, it predicts inflation at energy scales of four to five orders of magnitude below the Planck scale. At the onset of inflation, the mass of the tachyonic excitation, i.e. of the inflaton, turns out to be seven to eight orders of magnitude smaller than the Planck mass. (orig.)
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.
Nishi, Masato
2015-01-01
We discuss the large mass hierarchy problem in a braneworld model which represents our acceleratively expanding universe. The RS model with warped one extra dimension added to flat 4-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 4-dimensional space-time on the branes is $\\rm dS_4$. We study the model for both the cases of positive 5-dimensional cosmological constant $\\Lambda_5$ and negative one. In the positive $\\Lambda_5$ case, the 4-dimensional large hierarchy necessitates a 5-dimensional large hierarchy, and we cannot get a natural explanation. On the other hand, in the negative $\\Lambda_5$ case, the large hierarchy is naturally realized in the 5-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 $\\cal{O}\\rm (10^2)$ hierarchy of the 5-dimensional quantities....
Inflation as de Sitter instability
Cadoni, Mariano; Franzin, Edgardo; Mignemi, Salvatore
2016-09-01
We consider cosmological inflation generated by a scalar field slowly rolling off from a de Sitter maximum of its potential. The models belong to the class of hilltop models and represent the most general model of this kind in which the scalar potential can be written as the sum of two exponentials. The minimally coupled Einstein-scalar gravity theory obtained in this way is the cosmological version of a two-scale generalization of known holographic models, allowing for solitonic solutions interpolating between an AdS spacetime in the infrared and scaling solutions in the ultraviolet. We then investigate cosmological inflation in the slow-roll approximation. Our model reproduces correctly, for a wide range of its parameters, the most recent experimental data for the power spectrum of primordial perturbations. Moreover, it predicts inflation at energy scales of four to five orders of magnitude below the Planck scale. At the onset of inflation, the mass of the tachyonic excitation, i.e. of the inflaton, turns out to be seven to eight orders of magnitude smaller than the Planck mass.
Future Boundary Conditions in De Sitter Space
Anninos, Dionysios; Strominger, Andrew
2011-01-01
We consider asymptotically future de Sitter spacetimes endowed with an eternal observatory. In the conventional descriptions, the conformal metric at the future boundary I^+ is deformed by the flux of gravitational radiation. We however impose an unconventional future "Dirichlet" boundary condition requiring that the conformal metric is flat everywhere except at the conformal point where the observatory arrives at I^+. This boundary condition violates conventional causality, but we argue the causality violations cannot be detected by any experiment in the observatory. We show that the bulk-to-bulk two-point functions obeying this future boundary condition are not realizable as operator correlation functions in any de Sitter invariant vacuum, but they do agree with those obtained by double analytic continuation from anti-de Sitter space.
The Lamb shift in de Sitter spacetime
Zhou, Wenting
2010-01-01
We study the Lamb shift of both freely-falling and static two-level atoms in interaction with quantized conformally coupled massless scalar fields in the de Sitter-invariant vacuum. We find that the Lamb shifts of both freely-falling and static atoms are in structural similarity to that of an inertial atom immersed in a thermal bath in a Minkowski spacetime. For the freely-falling atom, the Lamb shift gets a correction as if it was immersed in a thermal bath at the Gibbons-Hawking temperature, thus revealing clearly the intrinsic thermal nature of de Sitter spacetime. For the static atom, the Lamb shift is affected by a combination of the effect of the intrinsic thermal nature of de Sitter spacetime and the Unruh effect associated with the inherent acceleration of the atom.
Living Near de Sitter Bubble Walls
Cho, J H; Cho, Jin-Ho; Nam, Soonkeon
2006-01-01
We study various bubble solutions in string/M theories obtained by double Wick rotations of (non-)extremal brane configurations. Typically, the geometry interpolates de Sitter space-time times non-compact extra-dimensional space in the near-bubble wall region and the asymptotic flat Minkowski space-time. These bubble solutions provide nice background geometries to reconcile string/M theories with de Sitter space-time. For the applications of these solutions to cosmology, we consider multi-bubble solutions and find a landscape of varying cosmological constant. Double Wick rotation in string/M theories introduces imaginary higher-form fields. Rather than regard these fields as classical pathologies, we interpret them as semi-classical decay processes of de Sitter vacuum via the production of spherical branes. We speculate on the possibility of solving the cosmological constant problem making use of the condensation of the spherical membranes.
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.
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 (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.
Quantum Correlations in de Sitter Space
Directory of Open Access Journals (Sweden)
Jiro Soda
2017-01-01
Full Text Available We study quantum correlation of a massive scalar field in a maximally entangled state in de Sitter space. We prepare two observers, one in a global chart and the other in an open chart of de Sitter space. We find that the state becomes less entangled as the curvature of the open chart gets larger. In particular, for the cases of a massless and a conformally coupled scalar field, the quantum entanglement vanishes in the limit of infinite curvature. However, we find that the quantum discord never disappears, even in the limit that entanglement disappears.
Ultraviolet Regularisation in de Sitter Space
Garbrecht, B
2006-01-01
The ultraviolet regularisation of Yukawa theory in de Sitter space is considered. We rederive the one-loop effective Candelas-Raine potentials, such that they agree with the corresponding Coleman-Weinberg potentials in flat space. Within supersymmetry, this provides a mechanism for the lifting of flat directions during inflation. For the purpose of calculating loop integrals, we propose a de Sitter-invariant modification of the regularisation procedure by Onemli and Woodard and show explicitly that the resulting self-energies are also invariant. Therefore, transplanckian effects do not necessarily leave an imprint on the spectrum of cosmic perturbations generated during inflation.
Living Near de Sitter Bubble Walls
Cho, Jin-Ho; Nam, Soonkeon
2006-01-01
We study various bubble solutions in string/M theories obtained by double Wick rotations of (non-)extremal brane configurations. Typically, the geometry interpolates de Sitter space-time times non-compact extra-dimensional space in the near-bubble wall region and the asymptotic flat Minkowski space-time. These bubble solutions provide nice background geometries reconciling string/M theories with de Sitter space-time. For the application of these solutions to cosmology, we consider multi-bubbl...
Non-Abelian cosmic strings in de Sitter and anti-de Sitter space
Santos, Antônio de Pádua; Bezerra de Mello, Eugênio R.
2016-09-01
In this paper we investigate the non-Abelian cosmic string in de Sitter and anti-de Sitter spacetimes. In order to do that we construct the complete set of equations of motion considering the presence of a cosmological constant. By using numerical analysis we provide the behavior of the Higgs and gauge fields and also of the metric tensor for specific values of the physical parameters of the theory. For the de Sitter case, we find the appearance of an horizon. This horizon is consequence of the presence of the cosmological constant, and its position strongly depends on the value of the gravitational coupling. In the anti-de Sitter case, we find that the system does not present horizons. In fact the new feature of this system is related with the behavior of the (00) and (z z ) components of the metric tensor. They present a strong increasing behavior for large distance from the string.
Extremal surfaces in de Sitter spacetime
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.
Matter-coupled de Sitter supergravity
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.
Special Sitters: Teenage Respite Care Providers.
Reid, Penny; Legaz, Mary Ann
1988-01-01
Camp Fire's Special Sitters Project addresses the need for respite care experienced by parents of disabled children. The project trains teenagers to care for young handicapped children and links the teenagers with parents who call for babysitting service. The project has been successfully replicated in five communities. (Author/JDD)
Asymptotically anti-de Sitter space-times: symmetries and conservation laws revisited
Barnich, G.; Brandt, F.; Claes, K.
2004-02-01
In this short note, we verify explicitly in static coordinates that the non trivial asymptotic Killing vectors at spatial infinity for anti-de Sitter space-times correspond one to one to the conformal Killing vectors of the conformally flat metric induced on the boundary. The fall-off conditions for the metric perturbations that guarantee finiteness of the associated conserved charges are derived.
Geometrothermodynamics for Black holes and de Sitter Space
Kurihara, Yoshimasa
2016-01-01
In this report, a general method to extract thermodynamic quantities from solutions of the Einstein equation is developed. In 1994, Wald established that the entropy of a black hole could be identified as a Noether charge associated with a Killing vector of a global space-time (pseudo-Riemann) manifold. We reconstruct Wald's method using geometrical language, e.g$.$, via differential forms defined on the local space-time (Minkowski) manifold. Concurrently, the abstract thermodynamics are also reconstructed using geometrical terminology, which is parallel to general relativity. The correspondence between the thermodynamics and general relativity can be seen clearly by comparing the two expressions. This comparison requires a modification of Wald's method. The new method is applied to Schwarzschild, Kerr, and Kerr--Newman black holes and de Sitter space. The results are consistent with previous results obtained using various independent methods. This strongly supports the validity of the area theorem for black ...
Black hole microstates in anti-de Sitter space
Shaghoulian, Edgar
2016-11-01
We extend a recently derived higher-dimensional Cardy formula to include angular momenta, which we use to obtain the Bekensten-Hawking entropy of anti-de Sitter black branes, compactified rotating branes, and large Schwarzschild/Kerr black holes. This is the natural generalization of Strominger's microscopic derivation of the Banados-Teitelboim-Zanelli black hole entropy to higher dimensions. We propose an extension to include U (1 ) charge, which agrees with the Bekenstein-Hawking entropy of large Reissner-Nordstrom/Kerr-Newman black holes at high temperature. We extend the results to an arbitrary hyperscaling-violation exponent (this captures the case of black D p -branes as a subclass) and reproduce logarithmic corrections.
Representing the vacuum polarization on de Sitter
Energy Technology Data Exchange (ETDEWEB)
Leonard, Katie E.; Woodard, Richard P. [Department of Physics, University of Florida, Gainesville, Florida 32611 (United States); Prokopec, Tomislav [Institute of Theoretical Physics (ITP) and Spinoza Institute, Utrecht University, Postbus 80195, 3508 TD Utrecht (Netherlands)
2013-03-15
Previous studies of the vacuum polarization on de Sitter have demonstrated that there is a simple, noncovariant representation of it in which the physics is transparent. There is also a cumbersome, covariant representation in which the physics is obscure. Despite being unwieldy, the latter form has a powerful appeal for those who are concerned about de Sitter invariance. We show that nothing is lost by employing the simple, noncovariant representation because there is a closed form procedure for converting its structure functions to those of the covariant representation. We also present a vastly improved technique for reading off the noncovariant structure functions from the primitive diagrams. And we discuss the issue of representing the vacuum polarization for a general metric background.
The bizarre anti-de Sitter spacetime
Sokołowski, Leszek M.
2016-08-01
Anti-de Sitter spacetime is important in general relativity and modern field theory. We review its geometrical features and properties of light signals and free particles moving in it. By applying only the elementary tools of tensor calculus, we derive ab initio of all these properties and show that they are really weird. One finds superluminal velocities of light and particles, infinite particle energy necessary to escape at infinite distance and spacetime regions inaccessible by a free fall, though reachable by an accelerated spaceship. Radial timelike geodesics are identical to the circular ones and actually all timelike geodesics are identical to one circle in a fictitious five-dimensional space. Employing the latter space, one is able to explain these bizarre features of anti-de Sitter spacetime; in this sense the spacetime is not self-contained. This is not a physical world.
Quantum discord in de Sitter space
Kanno, Sugumi; Soda, Jiro
2016-01-01
We study quantum discord between two free modes of a massive scalar field in a maximally entangled state in de Sitter space. We introduce two observers, one in a global chart and the other in an open chart of de Sitter space, and the observers determine the quantum discord created by each detecting one of the modes. This situation is analogous to the relationship between an observer in a Minkowski chart and another in one of the two Rindler charts in flat space. We find that the state becomes less entangled as the curvature of the open chart gets larger. In particular, for the cases of a massless, and a conformally coupled scalar field, the entanglement vanishes in the limit of infinite curvature. However, we find that the quantum discord never disappears even in the limit that entanglement disappears.
Energy Technology Data Exchange (ETDEWEB)
Cicoli, Michele [Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, Bologna, 40126 (Italy); INFN, Sezione di Bologna,via Irnerio 46, Bologna, 40126 (Italy); ICTP,Strada Costiera 11, Trieste, 34151 (Italy); Quevedo, Fernando [ICTP,Strada Costiera 11, Trieste, 34151 (Italy); DAMTP, Centre for Mathematical Sciences,Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Valandro, Roberto [Dipartimento di Fisica, Università di Trieste,Strada Costiera 11, Trieste, 34151 (Italy); INFN, Sezione di Trieste,Via Valerio 2, Trieste, 34127 (Italy); ICTP,Strada Costiera 11, Trieste, 34151 (Italy)
2016-03-21
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.
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.
Cosmic curvature from de Sitter equilibrium cosmology.
Albrecht, Andreas
2011-10-01
I show that the de Sitter equilibrium cosmology generically predicts observable levels of curvature in the Universe today. The predicted value of the curvature, Ω(k), depends only on the ratio of the density of nonrelativistic matter to cosmological constant density ρ(m)(0)/ρ(Λ) and the value of the curvature from the initial bubble that starts the inflation, Ω(k)(B). The result is independent of the scale of inflation, the shape of the potential during inflation, and many other details of the cosmology. Future cosmological measurements of ρ(m)(0)/ρ(Λ) and Ω(k) will open up a window on the very beginning of our Universe and offer an opportunity to support or falsify the de Sitter equilibrium cosmology.
On Gravitational Entropy of de Sitter Universe
Directory of Open Access Journals (Sweden)
S. C. Ulhoa
2016-01-01
Full Text Available The paper deals with the calculation of the gravitational entropy in the context of teleparallel gravity for de Sitter space-time. In such a theory it is possible to define gravitational energy and pressure; thus we use those expressions to construct the gravitational entropy. We use the temperature as a function of the cosmological constant and write the first law of thermodynamics from which we obtain the entropy. In the limit Λ≪1 we find that the entropy is proportional to volume, for a specific temperature’s choice; we find that ΔS≥0 as well. We also identify a phase transition in de Sitter space-time by analyzing the specific heat.
Asymptotically anti-de Sitter Proca Stars
Duarte, Miguel
2016-01-01
We show that complex, massive spin-1 fields minimally coupled to Einstein's gravity with a negative cosmological constant, admit asymptotically anti-de Sitter self-gravitating solutions. Focusing on 4-dimensional spacetimes, we start by obtaining analytical solutions in the test-field limit, where the Proca field equations can be solved in a fixed anti-de Sitter background, and then find fully non-linear solutions numerically. These solutions are a natural extension of the recently found asymptotically flat Proca stars and share similar properties with scalar boson stars. In particular, we show that they are stable against spherically symmetric linear perturbations for a range of fundamental frequencies limited by their point of maximum mass. We finish with an overview of the behavior of Proca stars in $5$ dimensions.
The bizarre anti-de Sitter spacetime
Sokolowski, Leszek M
2016-01-01
Anti--de Sitter spacetime is important in general relativity and modern field theory. We review its geometrical features and properties of light signals and free particles moving in it. Applying only elementary tools of tensor calculus we derive \\textit{ab initio\\/} all these properties and show that they are really weird. One finds superluminal velocities of light and particles, infinite particle energy necessary to escape at infinite distance and spacetime regions inaccessible by a free fall, though reachable by an accelerated spaceship. Radial timelike geodesics are identical to the circular ones and actually all timelike geodesics are identical to one circle in a fictitious five--dimensional space. Employing the latter space one is able to explain these bizarre features of anti--de Sitter spacetime; in this sense the spacetime is not self--contained. This is not a physical world.
Conformal properties of the extremal Schwarzschild de-Sitter spacetime
Gasperin, Edgar
2015-01-01
The conformal structure of the extremal Schwarzschild de-Sitter spacetime is analysed using the extended conformal Einstein field equations. Initial data for an asymptotic initial value problem for the extremal Schwarzschild de-Sitter spacetime is obtained. Using the insights gained from the analysis of the reference spacetime we consider nonlinear perturbations close to the extremal Schwarzschild de-Sitter spacetime. We show that small enough perturbations of initial data for the extremal Schwarzschild de-Sitter spacetime, away from the singularity, give rise to a solution to the Einstein field equations which exists to the future and has an asymptotic structure similar to that of the extremal Schwarzschild de-Sitter spacetime. Similarly, we obtain an existence and stability result for asymptotic initial data close to that of the extremal Schwarzschild de-Sitter spacetime in the non-singular region.
Twin Paradox in de Sitter Spacetime
Boblest, Sebastian; Wunner, Günter
2010-01-01
The "twin paradox" of special relativity offers the possibility to make interstellar flights within a lifetime. For very long journeys with velocities close to the speed of light, however, we have to take into account the expansion of the universe. Inspired by the work of Rindler on hyperbolic motion in curved spacetime, we study the worldline of a uniformly accelerated observer in de Sitter spacetime and the communication between the traveling observer and an observer at rest.
de Sitter Harmonies: Cosmological Spacetimes as Resonances
Maltz, Jonathan
2016-01-01
The aim of this work is to provided the details of a calculation summarized in the recent paper by Maltz and Susskind which conjectured a potentially rigorous framework where the status of de Sitter space is the same as that of a resonance in a scattering process. The conjecture being that transition amplitudes between certain states with asymptotically supersymmetric flat vacua contain resonant poles characteristic meta-stable intermediate states. A calculation employing constrained instantons is presented that illustrates this idea.
Proper time method in de Sitter space
Das, Ashok K
2015-01-01
We use the proper time formalism to study a (non-self-interacting) massive Klein-Gordon theory in the two dimensional de Sitter space. We determine the exact Green's function of the theory by solving the DeWitt-Schwinger equation as well as by calculating the operator matrix element. We point out how the one parameter family of arbitrariness in the Green's function arises in this method.
Gravitoelectromagnetism in (Anti) de Sitter Spacetime
de Matos, Clovis Jacinto
2009-01-01
The presence of a non-zero cosmological term in Einstein field equations can be interpreted as the physical possibility for preferred reference frames without breaking of general covariance. This possibility is used in the process of linearizing Einstein field equations in a de Sitter background, and in formulating the resulting equations in the framework of gravitoelectromagnetism. It is proposed that this set of equations only applies to the physical vacuum and not to baryonic (normal) matter.
On Gravitational Entropy of de Sitter Universe
Ulhoa, S C
2013-01-01
The paper deals with the calculation of the gravitational entropy in the context of teleparallel gravity for de Sitter space-time. In such a theory it is possible to define gravitational energy and pressure, thus we use those expressions to construct the gravitational entropy. We interpret the cosmological constant as the temperature and write the first law of thermodynamics. In the limit $\\Lambda\\ll 1$ we find that the entropy is proportional to volume and $\\Delta S\\geq 0$.
The Wave Function of Quantum de Sitter
Castro, Alejandra; Maloney, Alexander
2012-01-01
We consider quantum general relativity in three dimensions with a positive cosmological constant. The Hartle-Hawking wave function is computed as a function of metric data at asymptotic future infinity. The analytic continuation from Euclidean Anti-de Sitter space provides a natural integration contour in the space of metrics, allowing us -- with certain assumptions -- to compute the wave function exactly, including both perturbative and non-perturbative effects. The resulting wave function i...
Dynamical compactification from de Sitter space
Randall, Lisa; Johnson, Matthew C.; Carroll, Sean M.
2009-01-01
We show that \\(D\\)-dimensional de Sitter space is unstable to the nucleation of non-singular geometries containing spacetime regions with different numbers of macroscopic dimensions, leading to a dynamical mechanism of compactification. These and other solutions to Einstein gravity with flux and a cosmological constant are constructed by performing a dimensional reduction under the assumption of \\(q\\)-dimensional spherical symmetry in the full \\(D\\)-dimensional geometry. In addition to the fa...
Schwarzschild-de Sitter Metric and Inertial Beltrami Coordinates
Sun, Li-Feng; Deng, Ya; Huang, Wei; Hu, Sen
2013-01-01
Under consideration of coordinate conditions, we get the Schwarzschild-Beltrami-de Sitter (S-BdS) metric solution of the Einstein field equations with a cosmological constant $\\Lambda$. A brief review to the de Sitter invariant special relativity (dS-SR), and de Sitter general relativity (dS-GR, or GR with a $\\Lambda$) is presented. The Beltrami metric $B_{\\mu\
Koley, Ratna; Pal, Supratik; SenGupta, Soumitra
2009-01-01
Thermodynamic properties of Schwarzschild-Anti de-Sitter (Sch-AdS) and Reissner-Nordstr\\"om-Anti de-Sitter (RN-AdS) blackholes in 3+1 dimensional spacetime are studied critically with special reference to the warped braneworld black holes with non-vanishing cosmological constant on the brane. Explicit dependence of the thermodynamic variables on the parameters of the braneworld model such as the induced three brane cosmological constant as well as the bulk cosmological constant have been determined. Hawking-Page phase transition has been discussed for both Sch-AdS and RN-AdS black holes. At the phase transition point it is shown that the parameters mass, charge and cosmological constant get correlated by an inequality relation which originates from the background warped geometry model.
Regular black holes in de Sitter universe: scalar field perturbations and quasinormal modes
Fernando, Sharmanthie
2015-01-01
The purpose of this paper is to study quasinormal modes (QNM) of a regular black hole with a cosmological constant due to scalar perturbations. A detailed study of the QNM frequencies for the massless scalar field were done by varying the parameters of the theory such as the mass, magnetic charge, cosmological constant, and the spherical harmonic index. We have employed the sixth order WKB approximation to compute the QNM frequencies. We have also proved analytically that the $l=0$ mode for the massless field reach a constant value at late times. We have approximated the near-extreme regular-de Sitter black hole potential with the P$\\ddot{o}$schl-Teller potential to obtain exact frequencies. The null geodesics of the regular-de Sitter black hole is employed to describe the QNM frequencies at the eikonal limit ($ l >>1$).
Zhang, Li-Chun; Zhao, Hui-Hua; Zhao, Ren
2014-01-01
It is well known that there are black hole and the cosmological horizons for the Reissner-Nordstr\\"{o}m-de Sitter spacetime. Although the thermodynamic quantities on the horizons are not irrelevant, they satisfy the laws of black hole thermodynamics respectively. In this paper by considering the relations between the two horizons we give the effective thermodynamic quantities in $(n+2)$-dimensional Reissner-Nordstr\\"{o}m-de Sitter spacetime. The thermodynamic properties of these effective quantities are analyzed, moreover, the critical temperature, critical pressure and critical volume are obtained. We carry out an analytical check of Ehrenfest equations and prove that both Ehrenfest equations are satisfied. So the spacetime undergoes a second order phase transition at the critical point. This result is consistent with the nature of liquid--gas phase transition at the critical point, hence deepening the understanding of the analogy of charged dS spacetime and liquid--gas systems.
Surface tensions in horizon thermodynamics of Anti-de Sitter and de Sitter spacetimes
Chen, Deyou; Tao, Jun
2016-01-01
Adopting the surface tensions, we review the horizon thermodynamics of a Reissner-Nordstrom Anti-de Sitter black hole and a pure de Sitter spacetime. The modified first laws of thermodynamics, which obeys the corresponding Smarr relations, are gotten. For the black hole, the law is written as $\\delta E = T \\delta S - \\sigma\\delta A$ when the cosmological constant is fixed, where $E$ and $\\sigma$ are the Misner-Sharp mass and the surface tension, respectively. Treating the cosmological constant as an variable associated to the pressure, we rewrite the law as $\\delta E_0 = T \\delta S - \\sigma_{eff}\\delta A +V\\delta P$. The effective surface tension and pressure are obtained. The form of the modified first law of the de Sitter spacetime is different from that of the black hole.
Inflation Driven by q-de Sitter
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.
Compact space-like hypersurfaces in de Sitter space
Jinchi Lv
2005-01-01
We present some integral formulas for compact space-like hypersurfaces in de Sitter space and some equivalent characterizations for totally umbilical compact space-like hypersurfaces in de Sitter space in terms of mean curvature and higher-order mean curvatures.
Asymptotic symmetries of de Sitter space-time
Energy Technology Data Exchange (ETDEWEB)
Chrusciel, P.T. (Polska Akademia Nauk, Warsaw. Inst. Fizyki)
1981-01-01
The general form of the metric of an axially-symmetrical asymptotically de Sitter space-time fulfilling a radiation condition was found. Using the Bondi-Metzner method, the group of asymptotic symmetries of de Sitter space-time was found. The results obtained in this work agree only partially with Penrose's theory.
Kinematics of particles with quantum de Sitter symmetries
Barcaroli, Leonardo
2015-01-01
We present the first detailed study of the kinematics of free relativistic particles whose symmetries are described by a quantum deformation of the de Sitter algebra, known as $q$-de Sitter Hopf algebra. The quantum deformation parameter is a function of the Planck length $\\ell$ 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 $\\kappa$-Poincar\\'e 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 non-zero, effects due to spacetime curvature and non-trivial momentum space geometry are both present and affect each other. The particles' motion is then described in a full phase space picture. We fin...
Dirac oscillator and nonrelativistic Snyder-de Sitter algebra
Energy Technology Data Exchange (ETDEWEB)
Stetsko, M. M., E-mail: mstetsko@gmail.com, E-mail: mykola@ktf.franko.lviv.ua [Department of Theoretical Physics, Ivan Franko National University of Lviv, 12 Drahomanov Str., Lviv, UA-79005 (Ukraine)
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.
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.
Gravitational waves in a de Sitter universe
Bishop, Nigel T
2015-01-01
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.
Quantized Cosmology II: de Sitter Space
Weinstein, M; Weinstein, Marvin; Akhoury, Ratin
2003-01-01
This work applies the formalism developed in our earlier paper to de Sitter space. After exactly solving the relevant Heisenberg equations of motion we give a detailed discussion of the subtleties associated with defining physical states and the emergence of the classical theory. This computation provides the striking result that quantum corrections to this long wavelength limit of gravity eliminate the problem of the big crunch. We also show that the same corrections lead to possibly measureable effects on the CMB radiation. Finally, for the sake of completeness we discuss the special case, $\\Lambda=0$, and its relation to Minkowski space.
Anisotropic strange star with de Sitter spacetime
Kalam, Mehedi; Rahaman, Farook; Ray, Saibal; Hossein, Sk. Monowar; Karar, Indrani; Naskar, Jayanta
2012-12-01
Stars can be treated as self-gravitating fluid. Krori and Barua (J. Phys. A., Math. Gen. 8:508, 1975) gave an analytical solution to that kind of fluids. In this connection, we propose a de Sitter model for an anisotropic strange star with the Krori-Barua spacetime. We incorporate the existence of the cosmological constant on a small scale to study the structure of anisotropic strange stars and come to the conclusion that this doping is very well compatible with the well-known physical features of strange stars.
Construction of the de Sitter supergravity
Bergshoeff, Eric; Kallosh, Renata; Van Proeyen, Antoine
2016-01-01
Recently, the complete action for an N=1 pure supergravity action in 4 dimensions that allows a positive, negative or zero cosmological constant has been constructed. The action is the generalization of a Volkov-Akulov action for the Goldstino coupled to supergravity. The construction uses a nilpotent multiplet. This paper is written in honour of Philippe Spindel. AVP enjoyed collaborations and many interactions with Philippe, who has always appreciated very precise derivations. We use this occasion to give a very detailed account of the calculations that lead to the published results. We review aspects of supersymmetry with de Sitter backgrounds, the treatment of auxiliary fields, and other ingredients in the construction.
Lin, F L; Lin, Feng-Li; Soo, Chopin
1998-01-01
If cosmological constant is positive, a black hole is naturally described by the Schwarzschild-de Sitter solution with two horizons. We use the global method to extract the topological information and the selection rule for the Gibbons-Hawking temperature for the thermal vacua. These are related to the Euler number of the Euclidean section whose topology is more complicated than expected. We also point out the failure of the usual local method of conical singularity approach in dealing with multi-horizon scenarios.
Effective Lagrangian in de Sitter Spacetime
Kitamoto, Hiroyuki
2016-01-01
Scale invariant fluctuations of metric are universal feature of quantum gravity in de Sitter spacetime. We construct an effective Lagrangian which summarizes their implications on local physics by integrating super-horizon metric fluctuations. It shows infrared quantum effects are local and render fundamental couplings time dependent. We impose Lorenz invariance on the effective Lagrangian as it is required by the principle of general covariance. We show that such a requirement leads to unique physical predictions by fixing the quantization ambiguities. We explain how the gauge parameter dependence of observables is canceled. In particular the relative evolution speed of the couplings are shown to be gauge invariant.
Ghost inflation and de Sitter entropy
Jazayeri, Sadra; Saitou, Rio; Watanabe, Yota
2016-01-01
It has been known that the generalized second law of black hole thermodynamics is difficult, if not impossible, to be violated by ghost condensation. 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. We then propose a notion of cosmological Page time after inflation.
Membrane Instantons and de Sitter Vacua
Energy Technology Data Exchange (ETDEWEB)
Davidse, Marijn [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands); Saueressig, Frank [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht(Netherlands); Theis, Ulrich [Institute for Theoretical Physics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Vandoren, Stefan [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)
2005-09-01
We investigate membrane instanton effects in type-IIA strings compactified on rigid Calabi-Yau manifolds. These effects contribute to the low-energy effective action of the universal hypermultiplet. In the absence of additional fivebrane instantons, the quaternionic geometry of this hypermultiplet is determined by solutions of the three-dimensional Toda equation. We construct solutions describing membrane instantons, and find perfect agreement with the string theory prediction. In the context of flux compactifications we discuss how membrane instantons contribute to the scalar potential and the stabilization of moduli. Finally, we demonstrate the existence of meta-stable de Sitter vacua.
Supersymmetry in anti-de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Burges, C.J.C.; Freedman, D.Z.; Davis, S.; Gibbons, G.W.
1986-04-01
We consider the Wess-Zumino model in a background anti-de Sitter space-time in four dimensions (AdS)/sub 4/. We show that the naive generators of the O(3,2) isometry group, obtained by the Noether method, must be improved by adding surface terms. The improved generators have a manifestly positive definite energy density, are conserved, and have vanishing expectation value in a supersymmetric vacuum. The naive generators enjoy none of these properties. Propagators for scalar and spinor fields in (Ad S)/sub 4/ are presented, and a simple derivation of the trace anomaly is given.
De Sitter Uplift with Dynamical Susy Breaking
Retolaza, Ander
2015-01-01
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.
De Sitter uplift with Dynamical Susy Breaking
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.
Evaporation of the de Sitter Horizon
Markkanen, Tommi
2016-01-01
We investigate the stability of de Sitter space as seen by a local observer in expanding space. Using the Bunch-Davies vacuum as an initial state we find for a conformal scalar field and classical vacuum energy that tracing over the unobservable states beyond the cosmological horizon leads to a thermal spectrum of particles and that such a configuration is unstable under semi-classical backreaction. It is shown that this instability results in a gradual increase in the horizon size. Comments welcome.
Fence-sitters Protect Cooperation in Complex Networks
Zhang, Yichao; Bertelle, Cyrille; Zhou, Shi; Wang, Wenting
2014-01-01
Evolutionary game theory is one of the key paradigms behind many scientific disciplines from science to engineering. In complex networks, because of the difficulty of formulating the replicator dynamics, most of previous studies are confined to a numerical level. In this paper, we introduce a vectorial formulation to derive three classes of individuals' payoff analytically. The three classes are pure cooperators, pure defectors, and fence-sitters. Here, fence-sitters are the individuals who change their strategies at least once in the strategy evolutionary process. As a general approach, our vectorial formalization can be applied to all the two-strategies games. To clarify the function of the fence-sitters, we define a parameter, payoff memory, as the number of rounds that the individuals' payoffs are aggregated. We observe that the payoff memory can control the fence-sitters' effects and the level of cooperation efficiently. Our results indicate that the fence-sitters' role is nontrivial in the complex topol...
Spherically Symmetric Space Time with Regular de Sitter Center
Dymnikova, Irina
We formulate the requirements which lead to the existence of a class of globally regular solutions of the minimally coupled GR equations asymptotically de Sitter at the center.REFID="S021827180300358XFN001"> The source term for this class, invariant under boosts in the radial direction, is classified as spherically symmetric vacuum with variable density and pressure Tμ ν vac associated with an r-dependent cosmological term Λ μ ν = 8π GTμ ν vac, whose asymptotic at the origin, dictated by the weak energy condition, is the Einstein cosmological term Λgμν, while asymptotic at infinity is de Sitter vacuum with λ < Λ or Minkowski vacuum. For this class of metrics the mass m defined by the standard ADM formula is related to both the de Sitter vacuum trapped at the origin and the breaking of space time symmetry. In the case of the flat asymptotic, space time symmetry changes smoothly from the de Sitter group at the center to the Lorentz group at infinity through radial boosts in between. Geometry is asymptotically de Sitter as r → 0 and asymptotically Schwarzschild at large r. In the range of masses m ≥ mcrit, the de Sitter Schwarzschild geometry describes a vacuum nonsingular black hole (ΛBH), and for m < mcrit it describes G-lump — a vacuum selfgravitating particle-like structure without horizons. In the case of de Sitter asymptotic at infinity, geometry is asymptotically de Sitter as r → 0 and asymptotically Schwarzschild de Sitter at large r. Λμν geometry describes, dependently on parameters m and q = √ {Λ /λ } and choice of coordinates, a vacuum nonsingular cosmological black hole, self-gravitating particle-like structure at the de Sitter background λgμν, and regular cosmological models with cosmological constant evolving smoothly from Λ to λ.
Remarks on quantum ﬁeld theory on de Sitter and anti-de Sitter space-times
Indian Academy of Sciences (India)
Henri Epstein
2012-06-01
This is a short review of work done in common with Jacques Bros, Michel Gaudin, Ugo Moschella, and Vincent Pasquier. Among results are explicit Källén–Lehmann representations for products of two free-ﬁeld two-point functions in the de Sitter and the anti-de Sitter spaces and applications to particle decay.
Testing cosmic censorship conjecture near extremal black holes with cosmological constants
Zhang, Yuan
2013-01-01
Previously, we have shown that extremal Kerr-Newman black holes can be overcharged or overspun by a test particle, indicating possible violation of the cosmic censorship. In this paper, we consider extremal charged and rotating black holes with cosmological constants. By studying the motion of test particles, we find the following results: An extremal Reissner-Nordstrom anti-de Sitter (RN-AdS) black hole can be overcharged by a test particle but an extremal Reissner-Nordstrom de Sitter (RN-dS) black hole cannot be overcharged. We also show that both Kerr-de-Sitter (Kerr-dS) and Kerr-anti-de-Sitter (Kerr-AdS) black holes can be overspun by a test particle, implying a possible breakdown of the cosmic censorship conjecture. For the Kerr-AdS case, the overspinning requires that the energy of the particle be negative, a reminiscent of the Penrose process. In contrast to the extremal RN and Kerr black holes, in which cases the cosmic censorship is upheld, our results suggest some subtle relations between the cosmol...
Interacting Quantum Fields on de Sitter Space
Barata, João C A; Mund, Jen
2016-01-01
In 1975 Figari, H{\\o}egh-Krohn and Nappi constructed the ${\\mathscr P}(\\varphi)_2$ model on the two-dimensional de Sitter space. Here we complement their work with a number of new results. In particular, we show that $i.)$ the unitary irreducible representations of $SO_0(1,2)$ for both the principal and the complementary series can be formulated on the Hilbert space spanned by wave functions supported on the Cauchy surface; $ii.)$ physical infrared problems are absent on de Sitter space; $iii.)$ the interacting quantum fields satisfy the equations of motion in their covariant form; $iv.)$ the generators of the boosts and the rotations for the interacting quantum field theory arise by contracting the stress-energy tensor with the relevant Killing vector fields and integrating over the relevant line segments. They generate a reducible, unitary representation of the Lorentz group on the Fock space for the free field. We establish also relations to the modular objects of (relative) Tomita-Takesaki theory. In addi...
Cosmological Dynamics of de Sitter Gravity
Institute of Scientific and Technical Information of China (English)
AO Xi-Chen; LI Xin-Zhou; XI Ping
2011-01-01
@@ A new cosmological model based on the de Sitter gravity is investigated by dynamical analysis and numerical discussions.Via some transformations, the evolution equations of this model can form an autonomous system with 8 physical critical points.Among these critical points there exist one positive attractor and one negative attractor.The positive attractor describes the asymptotic behavior of late-time universe, which indicates that the universe will enter the exponential expansion phase, finally.Some numerical calculations are also carried out,which convince us of this conclusion derived from the dynamical analysis.%A new cosmological model based on the de Sitter gravity is investigated by dynamical analysis and numerical discussions.Via some transformations, the evolution equations of this model can form an autonomous system with 8 physical critical points.Among these critical points there exist one positive attractor and one negative attractor.The positive attractor describes the asymptotic behavior of late-time universe, which indicates that the universe will enter the exponential expansion phase, finally.Some numerical calculations are also carried out,which convince us of this conclusion derived from the dynamical analysis.
Casimir effect in de Sitter spacetime
Saharian, A A
2011-01-01
The vacuum expectation value of the energy-momentum tensor and the Casimir forces are investigated for a massive scalar field with an arbitrary curvature coupling parameter in the geometry of two parallel plates, on the background of de Sitter spacetime. The field is prepared in the Bunch--Davies vacuum state and is constrained to satisfy Robin boundary conditions on the plates. The vacuum energy-momentum tensor is non-diagonal, with the off-diagonal component corresponding to the energy flux along the direction normal to the plates. It is shown that the curvature of the background spacetime decisively influences the behavior of the Casimir forces at separations larger than the curvature radius of de Sitter spacetime. In dependence of the curvature coupling parameter and the mass of the field, two different regimes are realized, which exhibit monotonic or oscillatory behavior of the forces. The decay of the Casimir force at large plate separation is shown to be power-law, with independence of the value of the...
Zero modes in de Sitter background
Einhorn, Martin B
2016-01-01
There are five well-known zero modes in the conformal fluctuations of the metric of de Sitter (dS) spacetime. For Euclidean signature, they can be associated with certain spherical harmonics on the $S^4$ sphere, viz., the vector representation $\\bf5$ of the global $SO(5)$ isometry. They appear, for example, in the perturbative calculation of the effective action of de Sitter space, even on-shell, as well as in models containing matter fields. These zero modes are shown to be associated with a would-be collective excitation of the volume form $dV_4$, which alternatively may be viewed as a legacy of invariance under global translations in flat five-dimensions. We argue that these modes should be regarded as unphysical, similar to gauge modes, and removed from the spectrum of fluctuations. The effective action remains $SO(5)$ invariant after this surgery. For Lorentzian signature, a similar analysis is expected to apply to $SO(4,1)$ invariance, although there are subtleties that have not been resolved associated...
Four-dimensional anti-de Sitter black holes from a three-dimensional perspective Full complexity
Zanchin, V T; Lemos, J P S
2002-01-01
The dimensional reduction of black hole solutions in four-dimensional (4D) general relativity is performed and new 3D black hole solutions are obtained. Considering a 4D spacetime with one spacelike Killing vector, it is possible to split the Einstein-Hilbert-Maxwell action with a cosmological term in terms of 3D quantities. Definitions of quasilocal mass and charges in 3D spacetimes are reviewed. The analysis is then particularized to the toroidal charged rotating anti-de Sitter black hole. The reinterpretation of the fields and charges in terms of a three-dimensional point of view is given in each case, and the causal structure analyzed.
Stability of black holes and solitons in Anti-de Sitter space-time
Hartmann, Betti
2013-01-01
The stability of black holes and solitons in d-dimensional Anti-de Sitter space-time against scalar field condensation is discussed. The resulting solutions are "hairy" black holes and solitons, respectively. In particular, we will discuss static black hole solutions with hyperbolic, flat and spherical horizon topology and emphasize that two different type of instabilities exist depending on whether the scalar field is charged or uncharged, respectively. We will also discuss the influence of Gauss-Bonnet curvature terms. The results have applications within the AdS/CFT correspondence and describe e.g. holographic insulator/conductor/superconductor phase transitions.
Holographic Thermodynamic on the Brane in Topological Reissner-Nordstr\\"om de Sitter Space
Setare, M R
2003-01-01
We consider the brane universe in the bulk background of the topological Reissner-Nordstr\\"om de Sitter black holes. We show that the thermodynamic quantities (including entropy) of the dual CFT take usual special forms expressed in terms of Hubble parameter and its time derivative at the moment, when the brane crosses the black hole horizon or the cosmological horizon. We obtain the generalized Cardy-Verlinde formula for the CFT with an charge and cosmological constant, for any values of the curvature parameter $k$ in the Friedmann equations.
Biswas, Tirthabir; Koshelev, Alexey S.; Mazumdar, Anupam
2017-02-01
In this paper we provide the criteria for any generally covariant, parity preserving, and torsion-free theory of gravity to possess a stable de Sitter (dS) or anti-de Sitter (AdS) background. By stability we mean the absence of tachyonic or ghostlike states in the perturbative spectrum that can lead to classical instabilities and violation of quantum unitarity. While we find that the usual suspects, the F (R ) and F (G ) theories, can indeed possess consistent (A)dS backgrounds, G being the Gauss-Bonnet term, another interesting class of theories, string-inspired infinite derivative gravitational theories, can also be consistent around such curved vacuum solutions. Our study should not only be relevant for quantum gravity and early universe cosmology involving ultraviolet physics, but also for modifications of gravity in the infrared sector vying to replace dark energy.
Quasi-local energy with respect to de Sitter/anti-de Sitter reference
Chen, Po-Ning; Yau, Shing-Tung
2016-01-01
This article considers the quasi-local conserved quantities with respect to a reference spacetime with a cosmological constant. We follow the approach developed by the authors in [25,26,7] and define the quasi-local energy as differences of surface Hamiltonians. The ground state for the gravitational energy is taken to be a reference configuration in the de Sitter (dS) or Anti-de Sitter (AdS) spacetime. This defines the quasi-local energy with respect to the reference spacetime and generalizes our previous definition with respect to the Minkowski spacetime. Through an optimal isometric embedding into the reference spacetime, the Killing fields of the reference spacetime are transplanted back to the surface in the physical spacetime to complete the definitions of quasi-local conserved quantities. We also compute how the corresponding total conserved quantities evolve under the Einstein equation with a cosmological constant.
Biswas, Tirthabir; Mazumdar, Anupam
2016-01-01
In this paper we provide the criteria for any generally covariant, parity preserving, and torsion free theory of gravity to possess a stable de Sitter (dS) or anti-de Sitter (AdS) background. By stability we mean the absence of tachyonic or ghost-like states in the perturbative spectrum that can lead to classical instabilities and violation of quantum unitarity. While we find that the usual suspects, the F(R) and F(G) theories, can indeed possess consistent (A)dS backgrounds, G being the Gauss-Bonnet term, another interesting class of theories, string-inspired infinite derivative gravity, can also be consistent around such curved vacuum solutions. Our study should not only be relevant for quantum gravity and early universe cosmology involving ultraviolet physics, but also for modifications of gravity in the infra-red sector vying to replace dark energy .
On the Gravitational Wave in de Sitter Spacetime
Liu, L
2004-01-01
For there is always a wrong sign in the mass of graviton in the so-called perturbation expansion approximation of both Minkowski and de Sitter spacetimes, the existence of gravitational wave from the metric perturbation of de Sitter spacetime is doubtful. We try another way to start from the assumption that the gravitational wave equation should be both general covariant and conformal invariant and find that graviton is no longer a part of metric field, it has an effective mass of $m_g=\\sqrt{R/6}=% \\sqrt{2\\Lambda/3}$ with correct sign in de Sitter spacetime, though it's intrinsic mass remains zero.
Godel metric as a squashed anti-de Sitter geometry
Rooman, M.; Spindel, Ph.
1998-01-01
We show that the non flat factor of the Godel metric belongs to a one parameter family of 2+1 dimensional geometries that also includes the anti-de Sitter metric. The elements of this family allow a generalization a la Kaluza-Klein of the usual 3+1 dimensional Godel metric. Their lightcones can be viewed as deformations of the anti-de Sitter ones, involving tilting and squashing. This provides a simple geometric picture of the causal structure of these space-times, anti-de Sitter geometry app...
de Sitter limit of inflation and nonlinear perturbation theory
Jarnhus, Philip R
2007-01-01
We study the fourth order action of comoving curvature perturbations in an inflationary universe in order to understand more systematically the de Sitter limit in nonlinear cosmological perturbation theory. We derive the action of the curvature perturbations to fourth order in the comoving gauge, and show that it vanishes sufficiently fast in the de Sitter limit. By studying the de Sitter limit, we then extrapolate to the n'th order action of comoving curvature perturbations and discuss the slow-roll order of the n-point correlation function.
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.
Chen, Xiang
2012-01-01
We investigate the net force on a rigid Casimir cavity generated by vacuum fluctuations of electromagnetic field in three cases, de Sitter spacetime, de Sitter spacetime with weak gravitational field and Schwarzschild-de Sitter spacetime. In de Sitter spacetime 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 spacetime, we find the net force now can be splited into two parts, one is the gravitational force due to the induced effective mass between the two plates, the other one is generated by the metric structure of de Sitter spacetime. In order to investigate the vacuum fluctuation force on the rigid cavity under strong gravitational field, we perform the similar analysis in Schwarzschild-de Sitter spacetime, 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...
Fuzzy Euclidean wormholes in de Sitter space
Chen, Pisin; Yeom, Dong-han
2016-01-01
We investigate Euclidean wormholes in Einstein gravity with a massless scalar field in de Sitter space. Euclidean wormholes are possible due to the analytic continuation of the time as well as complexification of fields, where we need to impose the classicality after the Wick-rotation to the Lorentzian signatures. For some parameters, wormholes are preferred than Hawking-Moss instantons, and hence wormholes can be more fundamental than Hawking-Moss type instantons. Euclidean wormholes can be interpreted in three ways: (1) classical big bounce, (2) either tunneling from a small to a large universe or a creation of a collapsing and an expanding universe from nothing, and (3) either a quantum big bounce from a contracting to a bouncing phase or a creation of two expanding universes from nothing. These various interpretations shed some lights to the resolution of the singularity and tensions between various kinds of quantum gravity theories.
The Nonperturbative Quantum de Sitter Universe
Ambjørn, Jan; Jurkiewicz, J; Loll, R
2008-01-01
The dynamical generation of a four-dimensional classical universe from nothing but fundamental quantum excitations at the Planck scale is a long-standing challenge to theoretical physicists. A candidate theory of quantum gravity which achieves this goal without invoking exotic ingredients or excessive fine-tuning is based on the nonperturbative and background-independent technique of Causal Dynamical Triangulations. We demonstrate in detail how in this approach a macroscopic de Sitter universe, accompanied by small quantum fluctuations, emerges from the full gravitational path integral, and how the effective action determining its dynamics can be reconstructed uniquely from Monte Carlo data. We also provide evidence that it may be possible to penetrate to the sub-Planckian regime, where the Planck length is large compared to the lattice spacing of the underlying regularization of geometry.
The general de Sitter supergravity component action
Energy Technology Data Exchange (ETDEWEB)
Schillo, Marjorie; Woerd, Ellen van der [Institute for Theoretical Physics, University of Leuven (Belgium); Wrase, Timm [Institute for Theoretical Physics, TU Wien, Vienna (Austria)
2016-04-15
In this paper we review the appearance and utility of a nilpotent chiral multiplet in the context of supergravity, string theory and cosmology. Coupling a nilpotent chiral superfield to supergravity, one obtains what is called pure dS supergravity, a supergravity theory without scalar degrees of freedom that naturally has de Sitter (dS) solutions, and in which supersymmetry is non-linearly realized. We extend previous results that couple this dS supergravity to chiral and vector multiplets and derive the most general supergravity action for a single nilpotent chiral multiplet coupled to supergravity and an arbitrary number of chiral and vector multiplets. Based in part on the plenary talk given by T. W. at ''The String Theory Universe'', 21st European String Workshop, Leuven, September 7-11, 2015. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Fuzzy Euclidean wormholes in de Sitter space
Chen, Pisin; Hu, Yao-Chieh; Yeom, Dong-han
2017-07-01
We investigate Euclidean wormholes in Einstein gravity with a massless scalar field in de Sitter space. Euclidean wormholes are possible due to the analytic continuation of the time as well as complexification of fields, where we need to impose the classicality after the Wick-rotation to the Lorentzian signatures. For some parameters, wormholes are preferred than Hawking-Moss instantons, and hence wormholes can be more fundamental than Hawking-Moss type instantons. Euclidean wormholes can be interpreted in three ways: (1) classical big bounce, (2) either tunneling from a small to a large universe or a creation of a collapsing and an expanding universe from nothing, and (3) either a transition from a contracting to a bouncing phase or a creation of two expanding universes from nothing. These various interpretations shed some light on challenges of singularities. In addition, these will help to understand tensions between various kinds of quantum gravity theories.
De-Sitter spacetime as a superconductor
Momeni, D
2016-01-01
A superconductor is a material with infinite electric conductivity. Superconductivity and magnetism are happening as two opposite phenomena: superconductors need weak external magnetic fields (the Meissner effect) while generally with a strong external magnetic field we loose superconductivity. In \\cite{ref:I}-\\cite{Chernodub:2011tv} , the author showed that a very strong magnetic field can turn an empty space into a superconductor. We extended this idea to the constant curvature spaces, de Sitter (dS) spacetime and by a careful analysis of the modes for a spinor with arbitrary spin, we show that in a very similar condensation scenario as was proposed for flat space, we could transform dS to a superconductor.
Multifaceted Schwinger effect in de Sitter space
Sharma, Ramkishor; Singh, Suprit
2017-07-01
We investigate particle production à la the Schwinger mechanism in an expanding, flat de Sitter patch as is relevant for the inflationary epoch of our Universe. Defining states and particle content in curved spacetime is certainly not a unique process. There being different prescriptions on how that can be done, we have used the Schrödinger formalism to define instantaneous particle content of the state, etc. This allows us to go past the adiabatic regime to which the effect has been restricted in the previous studies and bring out its multifaceted nature in different settings. Each of these settings gives rise to contrasting features and behavior as per the effect of the electric field and expansion rate on the instantaneous mean particle number. We also quantify the degree of classicality of the process during its evolution using a "classicality parameter" constructed out of parameters of the Wigner function to obtain information about the quantum to classical transition in this case.
Ghost inflation and de Sitter entropy
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.
Entropy of Vaidya-deSitter Spacetime
Institute of Scientific and Technical Information of China (English)
LI Xiang; ZHAO Zheng
2001-01-01
As a statistical model of black hole entropy, the brick-wall method based on the thermal equilibrium in a large scale cannot be applied to the cases out of equilibrium, such as the non-static hole or the case with two horizons.However, the leading term of hole entropy called the Bekenstein-Hawking entropy comes from the contribution of the field near the horizon. According to this idea, the entropy of Vaidya-deSitter spacetime is calculated. A difference from the static case is that the result proportional to the area of horizon relies on a time-dependent cut-off. The condition of local equilibrium near the horizon is used as a working postulate.
Higher spin de Sitter quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Basu, Rudranil [Physique Théorique et Mathématique,Université Libre de Bruxelles and International Solvay Institutes,Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Indian Institute of Science Education and Research,Dr. Homi Bhabha Road, Pashan, Pune 411008 (India)
2015-10-23
We consider Einstein gravity with positive cosmological constant coupled with higher spin interactions and calculate Euclidean path integral perturbatively. We confine ourselves to the static patch of the 3 dimensional de Sitter space. This geometry, when Euclideanlized is equivalent to 3-sphere. However, infinite number of topological quotients of this space by discrete subgroups of the isometry group are valid Euclidean saddles as well. The case of pure Einstein gravity is known to give a diverging answer, when all saddles are included as contribution to the thermal partition functions (also interpreted as the Hartle Hawking state in the cosmological scenario). We show how higher spins, described by metric-Fronsdal fields help making the partition function finite. We find a curious fact that this convergence is not achieved by mere inclusion of spin-3, but requires spin-4 interactions.
Holographic Schwinger effect in de Sitter space
Fischler, Willy; Pedraza, Juan F; Tangarife, Walter
2014-01-01
Using the AdS/CFT correspondence, we construct the holographic dual of a tunneling instanton describing Schwinger pair creation in de Sitter space. Our approach allows us to extract the critical value of the electric field for which the potential barrier disappears, rendering the vacuum unstable. In addition, we compute the large-$\\lambda$, large-$N_c$ corrections to the nucleation rate and we find that it agrees with previous expectations based on perturbative computations. As a by-product of this investigation, we study the causal structure of the string dual to the nucleated pair as seen by different static observers and we show that it can be interpreted as a dynamical creation of a `gluonic' wormhole. We explain how this result provides further evidence for the ER=EPR conjecture as an equivalence between two descriptions of the same physical phenomenon.
Higher Spin de Sitter Quantum Gravity
Basu, Rudranil
2015-01-01
We consider Einstein gravity with positive cosmological constant coupled with higher spin interactions and calculate Euclidean path integral perturbatively. We confine ourselves to the static patch of the 3 dimensional de Sitter space. This geometry, when Euclideanlized is equivalent to 3-sphere. However, infinite number of topological quotients of this space by discrete subgroups of the isometry group are valid Euclidean saddles as well. Pure Einstein gravity is known to diverge, when all saddles are included as contribution to the thermal partition functions (also interpreted as the Hartle Hawking state of in the cosmological scenario). We show how higher spins, described by metric-Fronsdal fields help making the partition function finite. Counter-intuitively, this convergence is not achieved by mere inclusion of spin-3, but requires spin-4 interactions.
A de Sitter tachyon thick braneworld
Energy Technology Data Exchange (ETDEWEB)
Germán, Gabriel; Herrera-Aguilar, Alfredo; Malagón-Morejón, Dagoberto [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apdo. Postal 48-3, 62251, Cuernavaca, Morelos (Mexico); Mora-Luna, Refugio Rigel [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Ciudad Universitaria, C.P. 58040, Morelia, Michoacán (Mexico); Rocha, Roldão da, E-mail: gabriel@fis.unam.mx, E-mail: aha@fis.unam.mx, E-mail: malagon@ifm.umich.mx, E-mail: rigel@ifm.umich.mx, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, Rua Santa Adélia, 166 09210-170, Santo André, SP (Brazil)
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.
Dymnikova, Irina
2015-01-01
In nonlinear electrodynamics coupled to gravity, regular spherically symmetric electrically charged solutions satisfy the weak energy condition and have obligatory de Sitter centre. By the G\\"urses-G\\"ursey algorithm they are transformed to spinning electrically charged solutions asymptotically Kerr-Newman for a distant observer. Rotation transforms de Sitter center into de Sitter vacuum surface which contains equatorial disk $r=0$ as a bridge. We present general analysis of the horizons, ergoregions and de Sitter surfaces, as well as the conditions of the existence of regular solutions to the field equations. We find asymptotic solutions and show that de Sitter vacuum surfaces have properties of a perfect conductor and ideal diamagnetic, violation of the weak energy condition is prevented by the basic requirement of electrodynamics of continued media, and the Kerr ring singularity is replaced with the superconducting current.
de Sitter geodesics: reappraising the notion of motion
Pereira, J G
2011-01-01
de Sitter spacetime is transitive under a combination of translations and proper conformal transformations. Its usual family of geodesics, however, does not take into account this property. As a consequence, there are points in de Sitter spacetime which cannot be joined by any one of these geodesics. By taking into account the appropriate transitivity properties, a new family of geodesics is obtained whose trajectories are able to connect any two points of the de Sitter spacetime. They are, furthermore, consistent with the de Sitter momentum conservation. These geodesics introduce a new notion of motion, given by a combination of translations and proper conformal transformations, which may be important at very-high energies, where conformal symmetry plays a significant role.
de Sitter transitivity, conformal transformations and conservation laws
Pereira, J G; Savi, L L
2013-01-01
Minkowski spacetime is transitive under ordinary translations, a transformation that do not have matrix representations. The de Sitter spacetime, on the other hand, is transitive under a combination of translations and proper conformal transformations, which do have a matrix representation. Such matrix, however, is not by itself a de Sitter generator: it gives rise to a conformal re-scaling of the metric, a transformation not belonging to the de Sitter group, and in general not associated with diffeomorphisms in spacetime. When dealing with variational principles and Noether's theorem in de Sitter spacetime, therefore, it turns out necessary to regularise the transformations in order to eliminate the conformal re-scaling of the metric.
Extended quintessence, inflation, and stable de Sitter spaces
Faraoni, V; Faraoni, Valerio; Jensen, Michael N.
2006-01-01
A new gauge-invariant criterion for stability against inhomogeneous perturbations of de Sitter space is applied to scenarios of dark energy and inflation in scalar-tensor gravity. The results extend previous studies.
Thermodynamics of Schwarzschild-Beltrami-de Sitter Black Hole
Liu, Hang
2016-01-01
In this paper, we investigate the thermodynamical properties of Schwarzschild-Beltrami-de Sitter black hole introduced by Mu-Lin Yan \\textit{et al.} in 2013 by introducing inertial Beltrami coordinates to traditional non-inertial Schwarzschild-de Sitter metric which is the exact static spherical symmetry solution of Einstein equation with a positive cosmological constant $\\Lambda$. Based on this new metric, we compute entropy on all horizons and we give the entropy bound of the black hole. Hawking temperatures are calculated by considering a perturbation to entropy relations due to that there does not exist a killing horizon where the surface gravity related to Hawking temperature is defined well in this inertial coordinates. We also get the Smarr relations and the first law of thermodynamics. We find that the Schwarzschild-Beltrami-de Sitter black hole has almost the same thermodynamical properties as Schwarzschild-de Sitter black hole in the comparison between their corresponding thermodynamical quantities,...
N=2 supergravity models with stable de Sitter vacua
Fré, P; Van Proeyen, A; Fre', Pietro; Trigiante, Mario; Proeyen, Antoine Van
2003-01-01
In the present talk I shall review the construction of N=2 supergravity models exhibiting stable de Sitter vacua. These solutions represent the first instance of stable backgrounds with positive cosmological constant in the framework of extended supergravities (N >=2). After briefly reviewing the role of de Sitter space--times in inflationary cosmology, I shall describe the main ingredients which were necessary for the construction of gauged N=2 supergravity models admitting stable solutions of this kind.
Area spectrum of the D-dimensional de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Lopez-Ortega, A., E-mail: alopezo@ipn.m [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Instituto Politecnico Nacional, Calzada Legaria 694 Colonia Irrigacion, Delegacion Miguel Hidalgo, Mexico, D.F., C.P. 11500 (Mexico)
2009-11-23
The determination of the quantum area spectrum of a black hole horizon by means of its asymptotic quasinormal frequencies has been explored recently. We believe that for D-dimensional de Sitter horizon we must study if the idea works. Thus taking into account the local description of the thermodynamics of horizons proposed by Padmanabhan and the results of Hod, Kunstatter, and Maggiore we study the area spectrum of the D-dimensional de Sitter horizon.
Fuzzy de Sitter space-times via coherent states quantization
Gazeau, J P; Queva, J; Gazeau, Jean-Pierre; Mourad, Jihad; Queva, Julien
2006-01-01
A construction of the 2d and 4d fuzzy de Sitter hyperboloids is carried out by using a (vector) coherent state quantization. We get a natural discretization of the dS "time" axis based on the spectrum of Casimir operators of the respective maximal compact subgroups SO(2) and SO(4) of the de Sitter groups SO\\_0(1,2) and SO\\_0(1,4). The continuous limit at infinite spins is examined.
A Review of the N-bound and the Maximal Mass Conjectures Using NUT-Charged dS Spacetimes
Clarkson, R; Mann, R B
2004-01-01
The proposed dS/CFT correspondence remains an intriguing paradigm in the context of string theory. Recently it has motivated two interesting conjectures: the entropic N-bound and the maximal mass conjecture. The former states that there is an upper bound to the entropy in asymptotically de Sitter spacetimes, given by the entropy of pure de Sitter space. The latter states that any asymptotically de Sitter spacetime cannot have a mass larger than the pure de Sitter case without inducing a cosmological singularity. Here we review the status of these conjectures and demonstrate their limitation. We first describe a generalization of gravitational thermodynamics to asymptotically de Sitter spacetimes, and show how to compute conserved quantities and gravitational entropy using this formalism. From this we proceed to a discussion of the N-bound and maximal mass conjectures. We then illustrate that these conjectures are not satisfied for certain asymptotically de Sitter spacetimes with NUT charge. We close with a pr...
Directory of Open Access Journals (Sweden)
Olga Kichakova
2015-07-01
Full Text Available We investigate the thermodynamics of spherically symmetric black hole solutions in a four-dimensional Einstein–Yang–Mills-SU(2 theory with a negative cosmological constant. Special attention is paid to configurations with a unit magnetic charge. We find that a set of Reissner–Nordström–Anti-de Sitter black holes can become unstable to forming non-Abelian hair. However, the hairy black holes are never thermodynamically favoured over the full set of abelian monopole solutions. The thermodynamics of the generic configurations possessing a noninteger magnetic charge is also discussed.
'Micromanaging de Sitter holography'
Energy Technology Data Exchange (ETDEWEB)
Dong, Xi; Horn, Bart; /SLAC /Stanford U., Phys. Dept. /Santa Barbara, KITP; Silverstein, Eva; /Santa Barbara, KITP /SLAC /Stanford U., Phys. Dept.; 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
Dymnikova, Irina
2015-01-01
We address the question of regular primordial black holes with de Sitter interior, their remnants and gravitational vacuum solitons G-lumps as heavy dark matter candidates providing signatures for inhomogeneity of early universe, which is severely constrained by the condition that the contribution of these objects in the modern density does not exceed the total density of dark matter. Primordial black holes and their remnants seem to be most elusive among dark matter candidates. However, we reveal a nontrivial property of compact objects with de Sitter interior to induce proton decay or decay of neutrons in neutron stars. The point is that they can form graviatoms, binding electrically charged particles. Their observational signatures as dark matter candidates provide also signatures for inhomogeneity of the early universe. In graviatoms, the cross-section of the induced proton decay is strongly enhanced, what provides the possibility of their experimental searches. We predict proton decay paths induced by gr...
Induced rotation from de Sitter-Godel-de Sitter phase transition
Khodabakhshi, Sh
2016-01-01
The rotation of the cosmic objects is a universal phenomenon and its origin is still an open question. Here a model for the origin of rotation is presented. After an investigation of the phase transition of a scalar field in de Sitter and G\\"odel backgrounds, the motion of a test particle during the phase transitions is studied. Then using computer simulation for a congruence of particles, we show that although the local induced rotation is nonzero, the global rotation is below the observational limit.
Conservative Currents of Boundary Charges in AdS2+1 Gravity
Institute of Scientific and Technical Information of China (English)
FENG Sze-Shiang; WANG Bin; MENG Xin-He
2001-01-01
The boundary charge which constitutes the Virasoro algebra in (2-+ 1)-dirnensional anti-de Sitter gravity is derived by Noether theorem and diffeomorphic invariance. It shows that the boundary charge under discussion recently exhausts all the available independent nontrivial charges. Therefore, for any specific spacetime, the state counting via the central charge of the Virasoro algebra is exact.``
Holographic heavy ion collisions with baryon charge
Casalderrey-Solana, Jorge; van der Schee, Wilke; Triana, Miquel
2016-01-01
We numerically simulate collisions of charged shockwaves in Einstein-Maxwell theory in anti-de Sitter space as a toy model of heavy ion collisions with non-zero baryon charge. The stress tensor and the baryon current become well described by charged hydrodynamics at roughly the same time. The effect of the charge density on generic observables is typically no larger than 15\\%. %The rapidity profile of the charge is wider than the profile of the local energy density. We find significant stopping of the baryon charge and compare our results with those in heavy ion collision experiments.
Galaxy rotation curves in de Sitter space
van Putten, Maurice H P M
2014-01-01
The observed positive cosmological constant $\\Lambda$ and Hubble constant $H_0$ introduce a background of de Sitter gravitons of mass $m_0=\\sqrt{\\Lambda}\\hbar/c$ at a non-relativistic temperature $k_BT_{dS}=a_{H}\\hbar/\\pi c$, $a_H=H_0c$, where $\\hbar$ denotes the Planck constant and $c$ the velocity of light. In this cosmology, gravitational interactions are parameterized by the inverse temperature $\\beta=T_{dS}/T$ of the vacuum. The high and low $\\beta$ limits produce an acceleration $a\\simeq\\sqrt{a_Na_0}$, $a_0=2a_{H}/(1+\\beta_{dS})\\simeq 1.37\\times 10^{-8}$ cm s$^{-2}$, observed in observed galaxy rotation curves and, respectively, Newton's law. Gravitation may be anomalously weak in a transition about $2.17\\, {M_{11}^{1/2}} \\, \\mbox{kpc}$ around a galaxy of $M=M_{11}10^{11}M_\\odot$.
Quasinormal Quantization in deSitter Spacetime
Jafferis, Daniel L; Lysov, Vyacheslav; Ng, Gim Seng; Strominger, Andrew
2013-01-01
A scalar field in four-dimensional deSitter spacetime (dS_4) has quasinormal modes which are singular on the past horizon of the south pole and decay exponentially towards the future. These are found to lie in two complex highest-weight representations of the dS_4 isometry group SO(4,1). The Klein-Gordon norm cannot be used for quantization of these modes because it diverges. However a modified `R-norm', which involves reflection across the equator of a spatial S^3 slice, is nonsingular. The quasinormal modes are shown to provide a complete orthogonal basis with respect to the R-norm. Adopting the associated R-adjoint effectively transforms SO(4,1) to the symmetry group SO(3,2) of a 2+1-dimensional CFT. It is further shown that the conventional Euclidean vacuum may be defined as the state annihilated by half of the quasinormal modes, and the Euclidean Green function obtained from a simple mode sum. Quasinormal quantization contrasts with some conventional approaches in that it maintains manifest dS-invariance...
Tachyons in Classical de Sitter Vacua
Junghans, Daniel
2016-01-01
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 $\\eta$ 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 va...
Tachyons in classical de Sitter vacua
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.
Charged scalar perturbations around Garfinkle–Horowitz–Strominger black holes
Directory of Open Access Journals (Sweden)
Cheng-Yong Zhang
2015-10-01
Full Text Available We examine the stability of the Garfinkle–Horowitz–Strominger (GHS black hole under charged scalar perturbations. Employing the appropriate numerical methods, we show that the GHS black hole is always stable against charged scalar perturbations. This is different from the results obtained in the de Sitter and anti-de Sitter black holes. Furthermore, we argue that in the GHS black hole background there is no amplification of the incident charged scalar wave to cause the superradiance, so that the superradiant instability cannot exist in this spacetime.
Quantum Gravity Inde Sitter Space And Anti-de Sitter Space
Lippert, M S
2004-01-01
In this thesis, we consider two aspects of quantum gravity—the nature of holography in anti-de Sitter space and string theory models of de Sitter space. Searching for a holographic resolution of the black hole information paradox, we pursue the identity of precursors in the context of AdS/CFT. We consider precursors that encode bulk information causally disconnected from the boundary and whose measurement involves nonlocal bulk processes. Previous arguments that these precursors are large, undecorated Wilson loops are found to be flawed. We construct a toy model of holography which encapsulates the expected properties of precursors and compare it with previous such discussions. The information contained in precursors is argued to be encoded in the high-energy sector of the theory and not observable by low-energy measurements. These considerations lead us to propose a locality bound, which indicates where locality breaks down due to black hole or stringy effects. We apply the locality bound to Hawkin...
Thermal interpretation of infrared dynamics in de Sitter
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.
Logarithmic modes of critical gravity in de Sitter space-time
Setare, M R
2012-01-01
In this paper we consider the critical gravity in four dimensional de Sitter space-time. We obtain logarithmic modes in the critical point of the theory. Then we show that these logarithmic modes in de Sitter space-time obey similar properties as the ones in AdS-space-time. Our result in this paper indicate that critical gravity theories in de Sitter space-times could lead to a de Sitter/log CFT correspondence.
IR finite graviton propagators in de Sitter spacetime
Faizal, Mir; Mandal, Bhabani Prasad
2016-01-01
Graviton propagator diverges in certain gauges in de Sitter spacetime. We address this problem in this work by generalizing the infinitesimal BRST transformations in de Sitter spacetime to finite field-dependent BRST (FFBRST) transformations. These FFBRST transformations are symmetry of the classical action, but do not leave path integral measure invariant for the graviton theory in de Sitter spacetime. Due to the non-trivial Jacobian of such finite transformation the path integral measure changes and hence FFBRST transformation is capable of relating theories in two different gauges. We explicitly construct FFBRST transformation which relates theory with diverging graviton two-point function to theory with infrared (IR) finite graviton. The FFBRST transformation thus establishes that divergence in graviton two-point function may be only a gauge artifact.
The nonlinear evolution of de Sitter space instabilities
Niemeyer, J C; Niemeyer, Jens C.; Bousso, Raphael
2000-01-01
We investigate the quantum evolution of large black holes that nucleate spontaneously in de Sitter space. By numerical computation in the s-wave and one-loop approximations, we verify claims that such black holes can initially "anti-evaporate" instead of shrink. We show, however, that this is a transitory effect. It is followed by an evaporating phase, which we are able to trace until the black holes are small enough to be treated as Schwarzschild. Under generic perturbations, the nucleated geometry is shown to decay into a ring of de Sitter regions connected by evaporating black holes. This confirms that de Sitter space is globally unstable and fragments into disconnected daughter universes.
Super-gauge field in de Sitter universe
Energy Technology Data Exchange (ETDEWEB)
Parsamehr, S.; Takook, M.V. [Islamic Azad University, Department of Physics, Science and Research Branch, Tehran (Iran, Islamic Republic of); Enayati, M. [Razi University, Department of Physics, Kermanshah (Iran, Islamic Republic of)
2016-05-15
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. (orig.)
IR finite graviton propagators in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Faizal, Mir [University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Upadhyay, Sudhaker; Mandal, Bhabani Prasad [Banaras Hindu University, Department of Physics, Varanasi (India)
2016-04-15
The graviton propagator diverges in certain gauges in de Sitter spacetime. We address this problem in this work by generalizing the infinitesimal BRST transformations in de Sitter spacetime to finite field-dependent BRST (FFBRST) transformations. These FFBRST transformations are a symmetry of the classical action, but they do not leave the path integral measure invariant for the graviton theory in de Sitter spacetime. Due to the non-trivial Jacobian of such a finite transformation the path integral measure changes and hence the FFBRST transformation is capable of relating theories in two different gauges. We explicitly construct the FFBRST transformation which relates the theory with a diverging graviton two-point function to a theory with an infrared finite graviton. The FFBRST transformation thus establishes that the divergence in a graviton two-point function may be only a gauge artifact. (orig.)
Thermodynamic properties of black holes in de Sitter space
Li, Huai-Fan; Ma, Ya-Qin
2016-01-01
We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole in the view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit, which is consistent with the idea of Bousso and Hawking. By calculating heat capacity and Gibbs free energy, we find SdS black hole is always thermodynamically stable and RNdS black hole may undergoes phase transition at some points.
Thermodynamic properties of black holes in de Sitter space
Li, Huai-Fan; Ma, Meng-Sen; Ma, Ya-Qin
2017-01-01
We study the thermodynamic properties of Schwarzschild-de Sitter (SdS) black hole and Reissner-Nordström-de Sitter (RNdS) black hole in view of global and effective thermodynamic quantities. Making use of the effective first law of thermodynamics, we can derive the effective thermodynamic quantities of de Sitter black holes. It is found that these effective thermodynamic quantities also satisfy Smarr-like formula. Especially, the effective temperatures are nonzero in the Nariai limit. By calculating heat capacity and Gibbs free energy, we find SdS black hole is always thermodynamically stable and RNdS black hole may undergoes phase transition at some points.
Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime
Bavarsad, Ehsan; Stahl, Clément; Xue, She-Sheng
2016-11-01
We consider a charged scalar field in a D -dimensional de Sitter spacetime and investigate pair creation by a Schwinger mechanism in a constant electric field background. Using a semiclassical approximation the current of the created pairs has been estimated. We find that the semiclassical current of the created pairs in the strong electric field limit responds as ED/2. Going further but restricting to D =3 dimensional de Sitter spacetime, the quantum expectation value of the spacelike component of the induced current has been computed in the in-vacuum state by applying an adiabatic subtraction scheme. We find that, in the strong electric field limit, the current responds as E3/2. In the weak electric field limit the current has a linear response in E and an inverse dependence on the mass of the scalar field. In the case of a massless scalar field, the current varies with E-1 which leads to a phenomenon of infrared hyperconductivity. A new relation between infrared hyperconductivity, tachyons, and conformality is discussed, and a scheme to avoid an infrared hyperconductivity regime is proposed. In D dimension, we eventually presented some first estimates of the backreaction of the Schwinger pairs to the gravitational field, and we find a decrease of the Hubble constant due to the pair creation.
Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime
Bavarsad, Ehsan; Xue, She-Sheng
2016-01-01
We consider a charged scalar field in a $D$ dimensional de Sitter spacetime and investigate pair creation by Schwinger mechanism in a constant electric field background. Using a semiclassical approximation the current of the created pairs has been estimated. We find that, the semiclassical current of ultra-relativistic created pairs responses as $E^{\\frac{D}{2}}$. In particular, in $D=3$ dimensional de Sitter spacetime, the quantum expectation value of the spacelike component of the induced current has been computed in the in-vacuum state by applying an adiabatic subtraction scheme. We find that, in the strong electric field limit, the current responses as $E^{\\frac{3}{2}}$. In the weak electric field limit the current has a linear response in $E$ and an inverse dependence on the mass of the scalar field. In the case of a massless scalar field, the current varies with $E^{-1}$, which leads to a phenomenon of infrared hyperconductivity. A new relation between infrared hyperconductivity, tachyons and conformali...
Anninos, Dionysios; Pastras, Georgios
2009-07-01
The local and global thermal phase structure for asymptotically anti-de Sitter black holes charged under an abelian gauge group, with both Gauss-Bonnet and quartic field strength corrections, is mapped out for all parameter space. We work in the grand canonical ensemble where the external electric potential is held fixed. The analysis is performed in an arbitrary number of dimensions, for all three possible horizon topologies — spherical, flat or hyperbolic. For spherical horizons, new metastable configurations are exhibited both for the pure Gauss-Bonnet theory as well as the pure higher derivative gauge theory and combinations thereof. In the pure Gauss-Bonnet theory with negative coefficient and five or more spatial dimensions, two locally thermally stable black hole solutions are found for a given temperature. Either one or both of them may be thermally favored over the anti-de Sitter vacuum — corresponding to a single or a double decay channel for the metastable black hole. Similar metastable configurations are uncovered for the theory with pure quartic field strength corrections, as well combinations of the two types of corrections, in three or more spatial dimensions. Finally, a secondary Hawking-Page transition between the smaller thermally favored black hole and thermal anti-de Sitter space is observed when both corrections are turned on and their couplings are both positive.
Pair of accelerated black holes in a de Sitter background the dS C-metric
Dias, O J C; Dias, Oscar J. C.; Lemos, Jose' P. S.
2003-01-01
Following the work of Kinnersley and Walker for flat spacetimes, we have analyzed the anti-de Sitter C-metric in a previous paper. In the de Sitter case, Podolsky and Griffiths have established that the de Sitter C-metric (dS C-metric) found by Plebanski and Demianski describes a pair of accelerated black holes in the dS background with the acceleration being provided (in addition to the cosmological constant) by a strut that pushes away the two black holes or, alternatively, by a string that pulls them. We extend their analysis mainly in four directions. First, we draw the Carter-Penrose diagrams of the massless uncharged dS C-metric, of the massive uncharged dS C-metric and of the massive charged dS C-metric. These diagrams allow us to clearly identify the presence of two dS black holes and to conclude that they cannot interact gravitationally. Second, we revisit the embedding of the dS C-metric in the 5D Minkowski spacetime and we represent the motion of the dS C-metric origin in the dS 4-hyperboloid as we...
Quantum correlations with vacuum ambiguity in de Sitter space
Feng, Jun; Yang, Wen-Li; Zhang, Yao-Zhong; Fan, Heng
2012-01-01
We study the quantum correlations of free scalar field with vacuum ambiguity of de Sitter space. We show the occurrence of degradation of quantum entanglement and quantum discord between field modes for inertial observer in curved space due to the radiation associated with cosmological horizon. In particular, we find that quantum correlations can be used to encode infinite de Sitter invariant vacua, which correspond to infinite set of possible physical worlds. This may provide a superselection rule of physical vacuum via quantum information tasks. We also discuss the simulation of such quantum effects of vacuum ambiguity in ion trap experiments.
Symmetry Breaking In Curved Spacetime (de Sitter Space)
Kaiser, A
1998-01-01
Symmetry breaking has a central role in particle physics. Flat (Minkowski) space is a useful abstraction in most cases, but to study the real world, one must at some point consider nonzero spacetime curvature. Inflationary models in cosmology are an example where spacetime curvature and symmetry breaking together form the basis of the evolution of physics. In the first part of the thesis we examine symmetry breaking in a particular quantum state in de Sitter space, the vacuum state associated with the “ static” system. In the second part, we develop a framework for the effective potential method in de Sitter space, and check that it stays correct in the low curvature limit.
A No-go theorem for de Sitter compactifications?
Dass, N D H
2002-01-01
A general framework for studying compactifications in supergravity and string theories was introduced by Candelas, Horowitz, Strominger and Witten. This was further generalised to take into account the warp factor by de Wit, Smit and Hari Dass. Though the prime focus of the latter was to find solutions with nontrivial warp factors (shown not to exist under a variety of circumstances), it was shown there that de Sitter compactifications are generically disfavoured. In this note we place these results in the context of a revived interest in de Sitter spacetimes .
On de-Sitter Geometry in Cosmic Void Statistics
Gibbons, Gary W; Yoshida, Naoki; Chon, Sunmyon
2013-01-01
Starting from the geometrical concept of a 4-dimensional de-Sitter configuration of spheres in Euclidean 3-space and modelling voids in the Universe as spheres, we show that a uniform distribution over this configuration space implies a power-law for the void number density which is consistent with results from the excursion set formalism and from data, for an intermediate range of void volumes. We also discuss the effect of restricting the survey geometry on the void statistics. This work is a new application of de-Sitter geometry to cosmology and also provides a new geometrical perspective on self-similarity in cosmology.
Entropy of Kerr-de Sitter black hole
Li, Huai-Fan; Ma, Meng-Sen; Zhang, Li-Chun; Zhao, Ren
2017-07-01
Based on the consideration that the black hole horizon and the cosmological horizon of Kerr-de Sitter black hole are not independent of each other, we conjecture the total entropy of the system should have an extra term contributed from the correlations between the two horizons, except for the sum of the two horizon entropies. By employing globally effective first law and effective thermodynamic quantities, we obtain the corrected total entropy and find that the region of stable state for Kerr-de Sitter is related to the angular velocity parameter a, i.e., the region of stable state becomes bigger as the rotating parameters a is increases.
de Sitter angular momentum conservation in de Sitter gravity and spin origin of dark energy
Lu, Jia-An
2015-01-01
In de Sitter (dS) gravity, two kinds of conservation laws are derived. The first kind is a differential equation for a 5-dimensional (5d) dS-covariant angular momentum (AM) current, which unites the canonical energy-momentum (EM) and 4d AM tensors. The second kind presents a 5d dS-invariant AM current, which is conserved in the sense that its torsion-free divergence vanishes, and unites the total EM and 4d AM currents. It is found that the dS spin, i.e., the spin part of the dS-covariant current, contributes to the EM tensor with the contribution proportional to Lambda^{1/2}, where Lambda is the cosmological constant. Hence the dS spin may be one source of dark energy. All the results are compared to the ordinary Lorentz gravity.
New Results on Charged Compact Boson Stars
Kumar, Sanjeev; Kulshreshtha, Daya Shankar
2016-01-01
In this work we present some new results which we have obtained in a study of the phase diagram of charged compact boson stars in the theory involving massive complex scalar fields coupled to the U(1) gauge field and gravity in a conical potential in the presence of a cosmological constant $\\Lambda$ which we treat as a free parameter taking positive and negative values and thereby allowing us to study the theory in the de Sitter and Anti de Sitter spaces respectively. In our studies, we obtain four bifurcation points (possibility of more bifurcation points being not ruled out) in the de Sitter region. We present a detailed discussion of the various regions in our phase diagram with respect to four bifurcation points. Our theory is seen to have rich physics in a particular domain for positive values of $\\Lambda$ which is consistent with the accelerated expansion of the universe.
Stability of relativistic Bondi accretion in Schwarzschild-(anti-)de Sitter spacetimes
Mach, Patryk
2013-01-01
In a recent paper we investigated stationary, relativistic Bondi-type accretion in Schwarzschild-(anti-)de Sitter spacetimes. Here we study their stability, using the method developed by Moncrief. The analysis applies to perturbations satisfying the potential flow condition. We prove that global isothermal flows in Schwarzschild-anti-de Sitter spacetimes are stable, assuming the test-fluid approximation. Isothermal flows in Schwarzschild-de Sitter geometries and polytropic flows in Schwarzschild-de Sitter and Schwarzschild-anti-de Sitter spacetimes can be stable, under suitable boundary conditions.
An urgent need to understand and address the safety and well-being of hospital "sitters".
Schoenfisch, Ashley L; Pompeii, Lisa A; Lipscomb, Hester J; Smith, Claudia D; Upadhyaya, Mudita; Dement, John M
2015-12-01
Hospital sitters provide continuous observation of patients at risk of harming themselves or others. Little is known about sitters' occupational safety and well-being, including experiences with patient/visitor-perpetrated violence (type II). Data from surveys, focus groups, individual interviews at six U.S. hospitals were used to characterize the prevalence of and circumstance surrounding type II violence against sitters, as well as broader issues related to sitter use. Sitter respondents had a high 12-month prevalence of physical assault, physical threat, and verbal abuse compared to other workers in the hospital setting. Sitters and other staff indicated the need for clarification of sitters' roles regarding patient care and sitter well-being (e.g., calling for assistance, taking lunch/restroom breaks), training of sitters in personal safety and de-escalation, methods to communicate patient/visitor behaviors, and unit-level support. The burden of type II violence against hospital sitters is concerning. Policies surrounding sitters' roles and violence prevention training are urgently needed. © 2015 Wiley Periodicals, Inc.
Dynamically broken Anti-de Sitter action for gravity
Tresguerres, Romualdo
2008-01-01
Due to a suitable Higgs mechanism, a standard Anti-de Sitter gauge theory becomes spontaneously broken. The resulting Lorentz invariant gravitational action includes the Hilbert-Einstein term of ordinary Einstein-Cartan gravity with cosmological constant, plus contributions quadratic in curvature and torsion, and a scalar Higgs sector.
Thermal Interpretation of Infrared Dynamics in de Sitter
Rigopoulos, Gerasimos
2016-01-01
The infrared dynamics of a light, minimally coupled scalar field in de Sitter spacetime with Ricci curvature $R=12H$, averaged over horizon sized regions of physical volume $V_H=\\frac{4\\pi}{3}\\left(\\frac{1}{H}\\right)^3$, can be interpreted as Brownian motion in a medium with de Sitter temperature $T_{DS}=\\frac{\\hbar H}{2\\pi}$. We demonstrate this by employing path integral techniques, 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 $T_{DS}$ 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 $\\partial_\\mu\\phi$ and takes a well ...
Quantum Vacuum Instability of 'Eternal' de Sitter Space
Anderson, Paul R
2013-01-01
The Euclidean or Bunch-Davies O(4,1) invariant 'vacuum' 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. In de Sitter space, the same results are obtained either directly from the renormalized stress tensor of a massive scalar field, or for massless conformal fields of any spin, more directly from t...
Consistency of Scalar Potentials from Quantum de Sitter Space
Espinosa, José R; Trépanier, Maxime
2015-01-01
We derive constraints on the scalar potential of a quantum field theory in de Sitter space. The constraints, which we argue should be understood as consistency conditions for quantum field theories in dS space, originate from a consistent interpretation of quantum de Sitter space through its Coleman-De Luccia tunneling rate. Indeed, consistency of de Sitter space as a quantum theory of gravity with a finite number of degrees of freedom suggests the tunneling rates to vacua with negative cosmological constants be interpreted as Poincar\\'e recurrences. Demanding the tunneling rate to be a Poincar\\'e recurrence imposes two constraints, or consistency conditions, on the scalar potential. Although the exact consistency conditions depend on the shape of the scalar potential, generically they correspond to: 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 the fourth root of the vacuum energ...
Wave function of the de Sitter-Schwarzchild universe
Energy Technology Data Exchange (ETDEWEB)
Nagai, Hiroyuki (Kyushu Industrial Univ., Fukuoka (Japan))
1989-08-01
The wave function of the universe with an O(3) invariant inhomogeneous 3-space metric, called the de Sitter-Schwarzschild metric, is calculated under an appropriate boundary condition in the semi-classical approximation. The calculated result suggests that the quantum birth of the inhomogeneous universe cannot be disregarded. (author).
Cybernetically sound organizational structures I: de Sitter's design theory
Vriens, D.J.; Achterbergh, J.M.I.M.
2011-01-01
- Purpose – The purpose of this paper is to use de Sitter's design theory to show how organizational structures can be designed so as to attenuate organizational disturbances and amplify regulatory potential. It is argued that organizational structures with low values on so‐called design‐parameters
Lübbe, Christian
This article summarises joint work with Juan A. Valiente-Kroon on de Sitter-like spacetimes. The work re-examines the existence and stability problem using extended conformal field equations. In particular it makes use of a gauge based on conformal geodesics to fix the location of the conformal boundary a priori by choosing suitable initial data.
De Sitter universes and the emerging landscape in string theory
Indian Academy of Sciences (India)
Sandip P Trivedi
2004-10-01
We discuss a recent proposal to construct de Sitter vacua in string theory. It is based on flux compactifications in string theory where all the moduli are stabilised and supersymmetry is broken with control. The resulting picture is that of a complicated landscape with many vacua of widely varying values for the cosmological constant.
Consistency of scalar potentials from quantum de Sitter space
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.
Accretion on Reissner-Nordstrom-(anti)-de Sitter Black Hole with Global Monopole
Ahmed, Ayyesha K; Jamil, Mubasher
2016-01-01
In this paper, we investigate the accretion on the Reissner-Nordstr\\"{o}m anti-de-Sitter black hole with global monopole charge. We discuss the general solutions of accretion using the isothermal and polytropic equations of state for steady state, spherically symmetric, non-rotating accretion on the black hole. In the case of isothermal flow, we consider some specific fluids and derive their solutions at the sonic point as well. However, in case of polytropic fluid we calculate the general expressions only, as there exists no global (Bondi) solutions for polytropic test fluids. In addition to this, the effect of fluid on the mass accretion rate are also studied. Moreover, the large monopole parameter $\\beta$ greatly suppresses the maximum accretion rate.
Thermodynamics and Geometrothermodynamics of Charged black holes in Massive Gravity
Suresh, Jishnu; Prabhakar, Geethu; Kuriakose, V C
2016-01-01
The objective of this paper is to study the thermodynamics and thermodynamic geometry of charged de-Sitter and charged anti de-Sitter black hole solutions in massive gravity. In this study, the presence of a negative cosmological constant is identified as a thermodynamic variable, the pressure. By incorporating this idea, we study the effect of curvature parameter as well as the mass of graviton in the thermodynamics of the black hole system. We further extend our studies to different topology of the space time and its effects on phase transition and thermodynamics. In addition, the phase transition structure of the black hole and its interactions are reproduced using geometrothermodynamics.
Higher-spin charges in Hamiltonian form. I. Bose fields
Campoleoni, Andrea; Hörtner, Sergio; Leonard, Amaury
2016-01-01
We study asymptotic charges for symmetric massless higher-spin fields on Anti de Sitter backgrounds of arbitrary dimension within the canonical formalism. We first analyse in detail the spin-3 example: we cast Fronsdal's action in Hamiltonian form, we derive the charges and we propose boundary conditions on the canonical variables that secure their finiteness. We then extend the computation of charges and the characterisation of boundary conditions to arbitrary spin.
Higher-spin charges in Hamiltonian form. I. Bose fields
Energy Technology Data Exchange (ETDEWEB)
Campoleoni, A.; Henneaux, M. [Université Libre de Bruxelles and International Solvay InstitutesULB-Campus Plaine CP231, 1050 Brussels (Belgium); Hörtner, S. [Centro de Estudios Científicos (CECs),Casilla 1469, Valdivia (Chile); Leonard, A. [Université Libre de Bruxelles and International Solvay InstitutesULB-Campus Plaine CP231, 1050 Brussels (Belgium)
2016-10-26
We study asymptotic charges for symmetric massless higher-spin fields on Anti de Sitter backgrounds of arbitrary dimension within the canonical formalism. We first analyse in detail the spin-3 example: we cast Fronsdal’s action in Hamiltonian form, we derive the charges and we propose boundary conditions on the canonical variables that secure their finiteness. We then extend the computation of charges and the characterisation of boundary conditions to arbitrary spin.
Reissner-Nordstrom-anti-de Sitter nontopological solitons in broken Einstein-Maxwell-Higgs theory
Honda, Ethan
2017-01-01
Results are presented from numerical simulations of the Einstein-Maxwell-Higgs equations with a broken U(1) symmetry. Coherent nontopological soliton solutions are shown to exist that separate an anti-de Sitter (AdS) true vacuum interior from a Reissner-Nordstrom (RN) false vacuum exterior. The stability of these bubble solutions is tested by perturbing the charge of the coherent solution and evolving the time-dependent equations of motion. In the weak gravitational limit, the short-term stability depends on the sign of (ω /Q )∂ωQ , similar to Q -balls. The long-term end state of the perturbed solutions demonstrates a rich structure and is visualized using "phase diagrams." Regions of both stability and instability are shown to exist for κg≲0.015 , while solutions with κg≳0.015 were observed to be entirely unstable. Threshold solutions are shown to demonstrate time-scaling laws, and the space separating true and false vacuum end states is shown to be fractal in nature, similar to oscillons. Coherent states with superextremal charge-to-mass ratios are shown to exist and observed to collapse or expand, depending on the sign of the charge perturbation. Expanding superextremal bubbles induce phase transitions to the true AdS vacuum, while collapsing superextremal bubbles can form nonsingular strongly gravitating solutions with superextremal RN exteriors.
Evolution of thick domain walls in de Sitter universe
Dolgov, A D; Rudenko, A S
2016-01-01
We consider thick domain walls in a de Sitter universe following paper by Basu and Vilenkin. However, we are interested not only in stationary solutions found therein, but also investigate the general case of domain wall evolution with time. When the wall thickness parameter, $\\delta_0$, is smaller than $H^{-1}/\\sqrt{2}$, where $H$ is the Hubble parameter in de Sitter space-time, then the stationary solutions exist, and initial field configurations tend with time to the stationary ones. However, there are no stationary solutions for $\\delta_0 \\geq H^{-1}/\\sqrt{2}$. We have calculated numerically the rate of the wall expansion in this case and have found that the width of the wall grows exponentially fast for $\\delta_0 \\gg H^{-1}$. An explanation for the critical value $\\delta_{0c} = H^{-1}/\\sqrt{2}$ is also proposed.
Refining the boundaries of the classical de Sitter landscape
Andriot, David; Blåbäck, Johan
2017-03-01
We derive highly constraining no-go theorems for classical de Sitter backgrounds of string theory, with parallel sources; this should impact the embedding of cosmological models. We study ten-dimensional vacua of type II supergravities with parallel and backreacted orientifold O p -planes and D p -branes, on four-dimensional de Sitter spacetime times a compact manifold. Vacua for p = 3, 7 or 8 are completely excluded, and we obtain tight constraints for p = 4, 5, 6. This is achieved through the derivation of an enlightening expression for the four-dimensional Ricci scalar. Further interesting expressions and no-go theorems are obtained. The paper is self-contained so technical aspects, including conventions, might be of more general interest.
Refining the boundaries of the classical de Sitter landscape
Andriot, David
2016-01-01
We derive highly constraining no-go theorems for classical de Sitter backgrounds of string theory, with parallel sources; this should impact the embedding of cosmological models. We study ten-dimensional vacua of type II supergravities with parallel and backreacted orientifold Op-planes and Dp-branes, on four-dimensional de Sitter space-time times a compact manifold. Vacua for p=3, 7 or 8 are completely excluded, and we obtain tight constraints for p=4, 5, 6. This is achieved through the derivation of an enlightening expression for the four-dimensional Ricci scalar. Further interesting expressions and no-go theorems are obtained. The paper is self-contained so technical aspects, including conventions, might be of more general interest.
Instanton transition in thermal and moduli deformed de Sitter cosmology
Kounnas, Costas; Partouche, Hervé
2008-04-01
We consider the de Sitter cosmology deformed by the presence of a thermal bath of radiation and/or time-dependent moduli fields. Depending on the parameters, either a first or second-order phase transition can occur. In the first case, an instanton allows a double analytic continuation. It induces a probability to enter the inflationary evolution by tunnel effect from another cosmological solution. The latter starts with a big bang and, in the case the transition does not occur, ends with a big crunch. A temperature duality exchanges the two cosmological branches. In the limit where the pure de Sitter universe is recovered, the tunnel effect reduces to a “creation from nothing”, due to the vanishing of the big bang branch. However, the latter may be viable in some range of the deformation parameter. In the second case, there is a smooth evolution from a big bang to the inflationary phase.
Instanton transition in thermal and moduli deformed de Sitter cosmology
Kounnas, Costas
2007-01-01
We consider the de Sitter cosmology deformed by the presence of a thermal bath of radiation and/or time-dependent moduli fields. We find that an instanton allowing a double analytic continuation induces a probability to enter this inflationary evolution by tunnel effect from another cosmological solution. The latter starts with a big bang and, in the case the transition does not occur, ends with a big crunch. A temperature duality exchanges the two cosmological branches. In the limit where the pure de Sitter universe is recovered, the tunnel effect reduces to a ''creation from nothing'', due to the vanishing of the big bang branch. However, the latter happens to be viable in some range of the deformation parameters.
de Sitter symmetries and inflationary scalar-vector models
Directory of Open Access Journals (Sweden)
Juan P. Beltrán Almeida
2016-12-01
Full Text Available In this paper, we study the correspondence between a field theory in de Sitter space in D-dimensions and a dual conformal field theory in a euclidean space in (D − 1-dimensions. In particular, we investigate the form in which this correspondence is established for a system of interacting scalar and a vector fields propagating in de Sitter space. We analyze some necessary (but not sufficient conditions for which conformal symmetry is preserved in the dual theory in (D − 1-dimensions, making possible the establishment of the correspondence. The discussion that we address in this paper is framed on the context of inflationary cosmology. Thusly, the results obtained here pose some relevant possibilities of application to the calculation of the fields’s correlation functions and of the primordial curvature perturbation ζ, in inflationary models including coupled scalar and vector fields.
Power spectrum with auxiliary fields in de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Mohsenzadeh, M. [Islamic Azad University, Department of Physics, Qom Branch, Qom (Iran, Islamic Republic of); Tanhayi, M.R. [Islamic Azad University, Department of Physics, Central Tehran Branch, Tehran (Iran, Islamic Republic of); Yusofi, E. [Islamic Azad University, Department of Physics, Science and Research Ayatollah Amoli Branch, Amol, Mazandaran (Iran, Islamic Republic of)
2014-06-15
We use the auxiliary fields and (excited-) de Sitter solutions to study the standard power spectrum of primordial fluctuations of a scalar field in the early universe. The auxiliary fields are the negative norm solutions of the field equation and as is shown, with a fixed boundary condition, utilizing these states results in a finite power spectrum without any infinity. The power spectrum is determined by the de Sitter solutions up to some corrections and the space-time symmetry is not broken in this point of view. The modulation to the power spectrum is of order ((H)/(Λ)){sup 2}, where H is the Hubble parameter and Λ is the energy scale, e.g., the Planck scale. (orig.)
Massless Interacting Scalar Fields in de Sitter space
Nacir, Diana López; Trombetta, Leonardo G
2016-01-01
We present a method to compute the two-point functions for an $O(N)$ scalar field model in de Sitter spacetime, avoiding the well known infrared problems for massless fields. The method is based on an exact treatment of the Euclidean zero modes and a perturbative one of the nonzero modes, and involves a partial resummation of the leading secular terms. This resummation, crucial to obtain a decay of the correlation functions, is implemented along with a double expansion in an effective coupling constant $\\sqrt\\lambda$ and in $1/N$. The results reduce to those known in the leading infrared approximation and coincide with the ones obtained directly in Lorentzian de Sitter spacetime in the large $N$ limit. The new method allows for a systematic calculation of higher order corrections both in $\\sqrt\\lambda$ and in $1/N$.
The General Kerr-de Sitter Metrics in All Dimensions
Gibbons, G W; Page, D N; Pope, C N
2005-01-01
We give the general Kerr-de Sitter metric in arbitrary spacetime dimension D, with the maximal number [(D-1)/2] of independent rotation parameters. We obtain the metric in Kerr-Schild form, where it is written as the sum of a de Sitter metric plus the square of a null geodesic vector, and in generalised Boyer-Lindquist coordinates. The Kerr-Schild form is simpler for verifying that the Einstein equations are satisfied, and we have explicitly checked our results for all dimensions D \\le 11. We discuss the global structure of the metrics, and obtain formulae for the surface gravities and areas of the event horizons. We also obtain the Euclideanised solutions, and we construct complete non-singular compact Einstein spaces on associated S^{D-2} bundles over S^2.
Schwinger effect, backreaction and magnetogenesis in de Sitter spacetime
Stahl, Clément
2016-01-01
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.
Vacuum properties of nonsymmetric gravity in de Sitter space
Janssen, T; Janssen, Tomas; Prokopec, Tomislav
2007-01-01
We consider quantum effects of a massive antisymmetric tensor field on the dynamics of de Sitter space-time. Our starting point is the most general, stable, linearized Lagrangian arising in nonsymmetric gravitational theories (NGTs), where part of the antisymmetric field mass is generated by the cosmological term. We construct a renormalization group (RG) improved effective action by integrating out one loop vacuum fluctuations of the antisymmetric tensor field and show that, in the limit when the RG scale goes to zero, the Hubble parameter -- and thus the effective cosmological constant -- relaxes rapidly to zero. We thus conclude that quantum loop effects in de Sitter space can dramatically change the infrared sector of the on-shell gravity, making the expansion rate insensitive to the original (bare) cosmological constant.
Instanton transition in thermal and moduli deformed de Sitter cosmology
Energy Technology Data Exchange (ETDEWEB)
Kounnas, Costas [Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 rue Lhomond, F-75231 Paris cedex 05 (France)], E-mail: costas.kounnas@lpt.ens.fr; Partouche, Herve [Centre de Physique Theorique, Ecole Polytechnique, F-91128 Palaiseau cedex (France)], E-mail: herve.partouche@cpht.polytechnique.fr
2008-04-11
We consider the de Sitter cosmology deformed by the presence of a thermal bath of radiation and/or time-dependent moduli fields. Depending on the parameters, either a first or second-order phase transition can occur. In the first case, an instanton allows a double analytic continuation. It induces a probability to enter the inflationary evolution by tunnel effect from another cosmological solution. The latter starts with a big bang and, in the case the transition does not occur, ends with a big crunch. A temperature duality exchanges the two cosmological branches. In the limit where the pure de Sitter universe is recovered, the tunnel effect reduces to a 'creation from nothing', due to the vanishing of the big bang branch. However, the latter may be viable in some range of the deformation parameter. In the second case, there is a smooth evolution from a big bang to the inflationary phase.
Evolution of thick domain walls in de Sitter universe
Dolgov, A. D.; Godunov, S. I.; Rudenko, A. S.
2016-10-01
We consider thick domain walls in a de Sitter universe following paper by Basu and Vilenkin. However, we are interested not only in stationary solutions found therein, but also investigate the general case of domain wall evolution with time. When the wall thickness parameter, δ0, is smaller than H‑1/√2, where H is the Hubble parameter in de Sitter space-time, then the stationary solutions exist, and initial field configurations tend with time to the stationary ones. However, there are no stationary solutions for δ0 >= H‑1/√2. We have calculated numerically the rate of the wall expansion in this case and have found that the width of the wall grows exponentially fast for δ0 gg H‑1. An explanation for the critical value δ0c = H‑1/√2 is also proposed.
Huang, Yang; Li, Xin-Zhou
2016-01-01
Gaining insight into the behavior of a perturbed black hole surrounded by a reflecting mirror in asymptotically anti-de Sitter space-time is of great interest for current fundamental and practical research. In this work, a detailed analysis for superradiant stability of the system composed by a $D$-dimensional Reissner-Nordstr\\"{o}m-anti-de Sitter (RN-AdS) black hole and a reflecting mirror under charged scalar perturbations are presented in the linear regime. It is found that the stability of the system is heavily affected by the mirror radius as well as the mass of the scalar perturbation, AdS radius and the dimension of space-time. In a higher dimensional space-time, the degree of instability of the superradiant modes will be severely weakened. Nevertheless, the degree of instability can be magnified significantly by choosing a suitable value of the mirror radius. Remarkably, when the mirror radius is smaller than a threshold value the system becomes stable. We also find that massive charged scalar fields ...
Semiclassical fermion pair creation in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Stahl, Clément, E-mail: clement.stahl@icranet.org; Eckhard, Strobel, E-mail: eckhard.strobel@irap-phd.eu [ICRANet, Piazzale della Repubblica 10, 65122 Pescara (Italy); Dipartimento di Fisica, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome (Italy); Université de Nice Sophia Antipolis, 28 Avenue de Valrose, 06103 Nice Cedex 2 (France)
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.
One loop graviton corrections to dynamical photons in de Sitter
Glavan, D; Prokopec, Tomislav; Woodard, R P
2016-01-01
We employ a recent, general gauge computation of the one loop graviton contribution to the vacuum polarization on de Sitter to solve for one loop corrections to the photon mode function. The vacuum polarization takes the form of a gauge independent, spin 2 contribution and a gauge dependent, spin 0 contribution. We show that the leading secular corrections derive entirely from the spin 2 contribution.
Dynamics of quantum correlation and coherence in de Sitter universe
Huang, Zhiming
2017-09-01
In this article, we investigate the dynamics of quantum correlation and coherence for two atoms interacting with massless scalar field in the background de Sitter spacetime. We firstly analyze the solving process of master equation that describes the system evolution with initial Werner state. Then, we discuss the degradation, generation, revival and enhancement of quantum correlation and coherence for three cases of different initial states: zero correlation state, nonzero correlation separable state and maximally entangled state.
Discrete Torsion, (Anti) de Sitter D4-Brane and Tunneling
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.
de Sitter vacua from an anomalous gauge symmetry
Buchmuller, Wilfried; Ruehle, Fabian; Schweizer, Julian
2016-01-01
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 and a nonperturbative superpotential stabilizes the moduli and determines the size of the extra dimensions.
De Sitter vacua from an anomalous gauge symmetry
Energy Technology Data Exchange (ETDEWEB)
Buchmuller, Wilfried; Dierigl, Markus; Ruehle, Fabian; Schweizer, Julian
2016-03-15
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.
Snyder's quantized space-time and de Sitter special relativity
Institute of Scientific and Technical Information of China (English)
GUO Han-ying; HUANG Chao-guang; TIAN Yu; XU Zhan; ZHOU Bin
2007-01-01
There is a one-to-one correspondence between Snyder's model in de Sitter space of momenta and the dS-invariant special relativity as well as a minimum uncertaintylike relation.This indicates that physics at the Planck length lp and the scale R =(3/Λ)1/2 should be dual to each other and there is in-between gravity of local dS-invariance characterized by a dimensionless coupling constant g= lp/R～10-61.
Oscillating Shells in Anti-de Sitter Space
Mas, Javier
2015-01-01
We study the dynamics of a spherically symmetric thin shell of perfect fluid embedded in d-dimensional Anti-de Sitter space-time. In global coordinates, besides collapsing solutions, oscillating solutions are found where the shell bounces back and forth between two radii. The parameter space where these oscillating solutions exist is scanned in arbitrary number of dimensions. As expected AdS3 appears to be singled out.
The Thermal Bath of de Sitter from Holography
Chu, Chong-Sun
2016-01-01
We consider the AdS/dS CFT correspondence and study the nature of the thermal bath of the de Sitter field theory using holography. Unlike the temperature of a thermal field theory in flat spacetime, the temperature of a superconformal field theory on de Sitter space is an integral part of the theory and leaves intact the conformal symmetry and supersymmetry. In the dual AdS side, there is no black hole. Instead we have cosmological expansion of the de Sitter factor. We consider a number of different observables, such as the entanglement entropy, two point correlation function, Wilson loops corresponding to static and spinning mesons in the field theory, and study their thermal properties using holography. The former two quantities have trivial temperature dependence due to conformal symmetry. We compute the energy of the quark anti-quark bound state for a static meson, as well as the energy and the angular momentum for a spinning meson. We find that there is a maximum distance, as well as a maximum spin for t...
Cosmological Horizon Modes and Linear Response in de Sitter Spacetime
Anderson, Paul R; Mottola, Emil
2009-01-01
Linearized fluctuations of quantized matter fields and the spacetime geometry around de Sitter space are considered in the case that the matter fields are conformally invariant. Taking the unperturbed state of the matter to be the de Sitter invariant Bunch-Davies state, the linear variation of the stress tensor about its self-consistent mean value serves as a source for fluctuations in the geometry through the semi-classical Einstein equations. This linear response framework is used to investigate both the importance of quantum backreaction and the validity of the semi-classical approximation in cosmology. The full variation of the stress tensor, delta T^a_b contains two kinds of terms: (1) those that depend explicitly upon the linearized metric variation delta g_{cd} through the [T^a_b, T^{cd}] causal response function; and (2) state dependent variations, independent of delta g_{cd}. For perturbations of the first kind, the criterion for the validity of the semi-classical approximation in de Sitter space is ...
Quantum corrections for spinning particles in de Sitter
Fröb, Markus B.; Verdaguer, Enric
2017-04-01
We compute the one-loop quantum corrections to the gravitational potentials of a spinning point particle in a de Sitter background, due to the vacuum polarisation induced by conformal fields in an effective field theory approach. We consider arbitrary conformal field theories, assuming only that the theory contains a large number N of fields in order to separate their contribution from the one induced by virtual gravitons. The corrections are described in a gauge-invariant way, classifying the induced metric perturbations around the de Sitter background according to their behaviour under transformations on equal-time hypersurfaces. There are six gauge-invariant modes: two scalar Bardeen potentials, one transverse vector and one transverse traceless tensor, of which one scalar and the vector couple to the spinning particle. The quantum corrections consist of three different parts: a generalisation of the flat-space correction, which is only significant at distances of the order of the Planck length; a constant correction depending on the undetermined parameters of the renormalised effective action; and a term which grows logarithmically with the distance from the particle. This last term is the most interesting, and when resummed gives a modified power law, enhancing the gravitational force at large distances. As a check on the accuracy of our calculation, we recover the linearised Kerr-de Sitter metric in the classical limit and the flat-space quantum correction in the limit of vanishing Hubble constant.
Superradiant instabilities of asymptotically anti-de Sitter black holes
Green, Stephen R; Ishibashi, Akihiro; Wald, Robert M
2015-01-01
We study the linear stability of asymptotically anti-de Sitter black holes in general relativity in spacetime dimension $d\\ge4$. 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, $\\mathcal{E}$. 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 ...
On the global structure of Kerr-de Sitter spacetimes
Lake, Kayll
2015-01-01
Taking advantage of the natural length scale set by the cosmological constant $\\Lambda>0$, conditions on the parameters $(\\Lambda, M, a^{2})$ have been found, so that a Kerr-de Sitter specetime either describes a black hole with well separated horizons, or describes degenerate configurations where two or more horizons coincide. As long as the rotation parameter $a^{2}$ is subject to the constraint $a^{2}\\Lambda \\ll 1$, while the mass parameter $M$ is subject to: $ a^{2}[1+O(a^{2}\\Lambda)^{2})] \\frac {1}{9\\Lambda}[1+2a^{2}\\Lambda+O(a^{2}\\Lambda)^{2})]$ or $M^{2}< a^{2}[1+O(a^{2}\\Lambda)^{2})]$, the Kerr-de Sitter spacetime describes a ring-like singularity enclosed by two cosmological horizons. A Kerr-de Sitter spacetime may also describe configurations where the inner, the outer and one of the cosmological horizons coincide. However, we found that this coalescence occurs provided $M^{2}\\Lambda \\sim 1$ and due to the observed smallness of $\\Lambda$, these configurations are probably irrelevant in astrophys...
'Massless' vector field in de Sitter Universe
Energy Technology Data Exchange (ETDEWEB)
Garidi, T.; Gazeau, J-P. [APC, CNRS UMR 7164, Universite Paris 7, Denis Diderot, Boite 7020, F-75251 Paris Cedex 05 (France); Rouhani, S. [Plasma Physics Research Center, Islamic Azad University, P.O.BOX 14835-157, Tehran (Iran, Islamic Republic of); Takook, M.V. [Department of Physics, Razi University, Kermanshah (Iran, Islamic Republic of)
2006-04-15
In the present work the massless vector field in the de Sitter (dS) space has been quantized. 'Massless' is used here by reference to conformal invariance and propagation on the dS light-cone whereas 'massive' refers to those dS fields which contract at zero curvature unambiguously to massive fields in Minkowski space. Due to the gauge invariance of the massless vector field, its covariant quantization requires an indecomposable representation of the de Sitter group and an indefinite metric quantization. We will work with a specific gauge fixing which leads to the simplest one among all possible related Gupta-Bleuler structures. The field operator will be defined with the help of coordinate independent de Sitter waves (the modes) which are simple to manipulate and most adapted to group theoretical matters. The physical states characterized by the divergence-lessness condition will for instance be easy to identify. The whole construction is based on analyticity requirements in the complexified pseudo-Riemannian manifold for the modes and the two-point function. (authors)
Vacuum Quantum Effects for Parallel Plates Moving by Uniform Acceleration in Static de Sitter Space
Setare, M R
2004-01-01
The Casimir forces on two parallel plates moving by uniform proper acceleration in static de Sitter background due to conformally coupled massless scalar field satisfying Dirichlet boundary conditions on the plates is investigated. Static de Sitter space is conformally related to the Rindler space, as a result we can obtain vacuum expectation values of energy-momentum tensor for conformally invariant field in static de Sitter space from the corresponding Rindler counterpart by the conformal transformation.
(Anti-)de Sitter Black Hole Thermodynamics and the Generalized Uncertainty Principle
Bolen, B; Bolen, Brett; Cavaglia, Marco
2004-01-01
We extend the derivation of the Hawking temperature of a Schwarzschild black hole via the Heisenberg uncertainty principle to the de Sitter and anti-de Sitter spacetimes. The thermodynamics of the Schwarzschild-(anti-)de Sitter black holes is obtained from the generalized uncertainty principle of string theory and non-commutative geometry. This may explain why the thermodynamics of (anti-)de Sitter-like black holes admits a holographic description in terms of a dual quantum conformal field theory, whereas the thermodynamics of Schwarzschild-like black holes does not.
Medrano, Marina Ramon
2007-01-01
An effective string theory in physically relevant cosmological and black hole space times is reviewed. Explicit computations of the quantum string entropy, partition function and quantum string emission by black holes (Schwarzschild, rotating, charged, asymptotically flat, de Sitter dS and AdS space times) in the framework of effective string theory in curved backgrounds provide an amount of new quantum gravity results as: (i) gravitational phase transitions appear with a distinctive universal feature: a square root branch point singularity in any space time dimensions. This is of the type of the de Vega - Sanchez transition for the thermal self-gravitating gas of point particles. (ii) There are no phase transitions in AdS alone. (iii) For $dS$ background, upper bounds of the Hubble constant H are found, dictated by the quantum string phase transition.(iv) The Hawking temperature and the Hagedorn temperature are the same concept but in different (semiclassical and quantum) gravity regimes respectively. (v) Th...
Boundary Dynamics of Three-Dimensional Asymptotically Anti-de Sitter Space-Times
van Albada, Sacha Jennifer
2016-01-01
This thesis is organized as follows. In Chapter 2, some preliminaries are given on isometries and conformal symmetries, and we become familiar with the Virasoro algebra. Two examples of classical central charges are discussed. Chapter 3 contains an introduction to the Hamiltonian formulation of gauge theories in the context of Maxwell theory. The knowledge gained in Chapter 3 is applied to general relativity in Chapter 4. The Hamiltonian is shown to acquire a surface term due to the presence of the boundary. The geometrical properties of anti-de Sitter space and the BTZ black hole are the subject of Chapter 5. The main part of the discussion follows in Chapter 6, which contains the calculation of the central charge in the asymptotic symmetry algebra of asymptotically AdS3 space-times. After some preliminaries on the AdS/CFT correspondence and Chern-Simons theory, the derivation of the boundary conformal field theory is summarized in Chapter 7. Finally, Strominger's entropy calculation is presented in Chapter ...
Quasi-normal modes for de Sitter-Reissner-Nordstr\\"om Black Holes
Iantchenko, Alexei
2014-01-01
The quasi-normal modes for black holes are the resonances for the scattering of incoming waves by black holes. Here we consider scattering of massless charged Dirac fields propagating in the outer region of de Sitter-Reissner-Nordstr{\\"o}m Black Holes, which is spherically symmetric charged exact solution of the Einstein-Maxwell equations. Using the spherical symmetry of the equation and restricting to a fixed harmonic the problem is reduced to a scattering problem for the 1D massless Dirac operator on the line. The resonances for the problem are related to the resonances for a certain semi-classical Schr{\\"o}dinger operators with exponentially decreasing positive potentials. The asymptotic distribution of the resonances are close to the lattice of quasi-poles associated to the non-degenerate maxima of the potentials. Using the techniques of semi-classical Birkhoff normal form we give the complete asymptotic formulas for the resonances. In particular, we calculate the first three leading terms in the expansio...
Graviton loop corrections to vacuum polarization in de Sitter in a general covariant gauge
Glavan, D.; Miao, S. P.; Prokopec, Tom; Woodard, R. P.
2015-01-01
We evaluate the one-graviton loop contribution to the vacuum polarization on de Sitter background in a 1-parameter family of exact, de Sitter invariant gauges. Our result is computed using dimensional regularization and fully renormalized with Bogoliubov, Parasiuk, Hepp and Zimmerman counterterms,
Lightlike hypersurfaces along spacelike submanifolds in anti-de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Izumiya, Shyuichi, E-mail: izumiya@math.sci.hokudai.ac.jp [Department of Mathematics, Hokkaido University, Sapporo 060-0810 (Japan)
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.
de Sitter vacua in N=8 supergravity and slow-roll conditions
Energy Technology Data Exchange (ETDEWEB)
Dall' Agata, G., E-mail: dallagat@pd.infn.it [Dipartimento di Fisica ' Galileo Galilei' , Universita di Padova, Via Marzolo 8, 35131 Padova (Italy); INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy); Inverso, G. [Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , Via della Ricerca Scientifica, 00133 Roma (Italy); INFN, Sezione di Roma 2, ' Tor Vergata' , Via della Ricerca Scientifica, 00133 Roma (Italy)
2013-01-08
In this Letter we discuss de Sitter vacua in maximal gauged supergravity in 4 dimensions. We show that, using the newly deformed theories introduced in Dall'Agata et al. (2012) [1], we can obtain de Sitter vacua with arbitrarily flat tachyonic directions in the SO(4,4){sub c} models.
Achterbergh, J.M.I.M.; Vriens, D.J.
2011-01-01
- Purpose – The purpose of this paper is to show how the viable system model (VSM) and de Sitter's design theory can complement each other in the context of the diagnosis and design of viable organizations. - Design/methodology/approach – Key concepts from Beer's model and de Sitter's design theory
Dirac-Coulomb scattering with plane wave energy eigenspinors on de Sitter expanding universe
Cotaescu, Ion I
2007-01-01
The lowest order contribution of the amplitude of Dirac-Coulomb scattering in de Sitter spacetime is calculated assuming that the initial and final states of the Dirac field are described by exact solutions of the free Dirac equation on de Sitter spacetime with a given energy and helicity. We find that the total energy is conserved in the scattering process.
Kinematics of particles with quantum-de Sitter-inspired symmetries
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.
Sequestered de Sitter string scenarios: soft-terms
Aparicio, Luis; Cicoli, Michele; Krippendorf, Sven; Maharana, Anshuman; Muia, Francesco; Quevedo, Fernando
2014-11-01
We analyse soft supersymmetry breaking in type IIB de Sitter string vacua after moduli stabilisation, focussing on models in which the Standard Model is sequestered from the supersymmetry breaking sources and the spectrum of soft-terms is hierarchically smaller than the gravitino mass m 3/2. Due to this feature, these models are compatible with gauge coupling unification and TeV scale supersymmetry with no cosmological moduli problem. We determine the influence on soft-terms of concrete realisations of de Sitter vacua constructed from supersymmetric effective actions. One of these scenarios provides the first study of soft-terms for consistent string models embedded in a compact Calabi-Yau manifold with all moduli stabilised. Depending on the moduli dependence of the Kähler metric for matter fields and on the mechanism responsible to obtain a de Sitter vacuum, we find two scenarios for phenomenology: (i) a split-supersymmetry scenario where gaugino masses are suppressed with respect to scalar masses: M 1/2 ˜ m 3/2 ɛ ≪ m 0 ˜ m 3/2 ≪ m 3/2 for ɛ ˜ m 3/2 /M P ≪ 1; (ii) a typical MSSM scenario where all soft-terms are of the same order: M 1/2 ˜ m 0 ˜ m 3/2 ɛ ≪ m 3/2. Background fluxes determine the numerical coefficients of the soft-terms allowing for small variations of parameters as is necessary to confront data and to interpolate between different scenarios. We comment on different stringy origins of the μ-term and potential sources of desequestering.
Anninos, Dionysios
2009-01-01
The local and global thermal phase structure for asymptotically anti-de Sitter black holes charged under an abelian gauge group, with both Gauss-Bonnet and quartic field strength corrections, is mapped out for all parameter space. We work in the grand canonical ensemble where the external electric potential is held fixed. The analysis is performed in an arbitrary number of dimensions, for all three possible horizon topologies - spherical, flat or hyperbolic. For spherical horizons, new metastable configurations are exhibited both for the pure Gauss-Bonnet theory as well as the pure higher derivative gauge theory and combinations thereof. In the pure Gauss-Bonnet theory with negative coefficient and five or more spatial dimensions, two locally thermally stable black hole solutions are found for a given temperature. Either one or both of them may be thermally favored over the anti-de Sitter vacuum - corresponding to a single or a double decay channel for the metastable black hole. Similar metastable configurati...
Kinematics of a relativistic particle with de Sitter momentum space
Energy Technology Data Exchange (ETDEWEB)
Arzano, Michele [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Leuvenlaan 4, Utrecht 3584 TD (Netherlands); Kowalski-Glikman, Jerzy, E-mail: marzano@uu.nl, E-mail: jkowalskiglikman@ift.uni.wroc.pl [Institute for Theoretical Physics, University of Wroclaw, Pl. Maxa Borna 9, Pl-50-204 Wroclaw (Poland)
2011-05-21
We discuss kinematical properties of a free relativistic particle with deformed phase space in which momentum space is given by (a submanifold of) de Sitter space. We provide a detailed derivation of the action, Hamiltonian structure and equations of motion for such a free particle. We study the action of deformed relativistic symmetries on the phase space and derive explicit formulae for the action of the deformed Poincare group. Finally we provide a discussion on parametrization of the particle worldlines stressing analogies and differences with ordinary relativistic kinematics.
The broken string in anti-de Sitter space
Vegh, David
2015-01-01
This paper describes an efficient method for solving the classical string equations of motion in (2+1)-dimensional anti-de Sitter spacetime. Exact string solutions are identified that are the analogs of piecewise linear strings in flat space. They can be used to approximate any smooth string motion to arbitrary accuracy. Cusps on the string move with the speed of light and their collisions are described by a Picard-Lefschetz-type formula. Explicit examples are shown with the string ending on two boundary quarks. The technique is ideally suited for numerical simulations. A Mathematica notebook that has been used to generate the relevant figures is also included.
Cosmic censorship of rotating Anti-de Sitter black hole
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.
Conformal symmetry breaking operators for anti-de Sitter spaces
Kobayashi, Toshiyuki; Pevzner, Michael
2016-01-01
For a pseudo-Riemannian manifold $X$ and a totally geodesic hypersurface $Y$, we consider the problem of constructing and classifying all linear differential operators $\\mathcal{E}^i(X) \\to \\mathcal{E}^j(Y)$ between the spaces of differential forms that intertwine multiplier representations of the Lie algebra of conformal vector fields. Extending the recent results in the Riemannian setting by Kobayashi-Kubo-Pevzner [Lecture Notes in Math.~2170, (2016)], we construct such differential operators and give a classification of them in the pseudo-Riemannian setting where both $X$ and $Y$ are of constant sectional curvature, illustrated by the examples of anti-de Sitter spaces and hyperbolic spaces.
Twistor variables for Anti-de Sitter (super)particles
Arvanitakis, Alex S; Townsend, Paul K
2016-01-01
Starting from the classical action for a spin-zero particle in a (D + 1)-dimensional anti-Sitter spacetime, we recover the Breitenlohner-Freedman bound by quantization. We then find a twistor form of the action for D = 3, 4, 6 for which the SO(2, D) isometry group is a linearly realized symmetry. The supertwistor generalization yields superparticle actions that are manifestly invariant under the isometry supergroup of the near-horizon geometries of the M2, D3 and M5 brane solutions of string/M-theory; in each case quantization yields a supermultiplet with 128 + 128 states.
Locally anti de Sitter spaces and deformation quantization
Claessens, Laurent
2009-01-01
In the first part we define a "BTZ" black hole in anti de Sitter space in any dimension by defining as "singular" the closed orbits of the Iwasawa component of SO(2,n). In the second part, a strict quantization of the black hole by action of group is performed and its Dirac operator is computed. We introduce, in the appendix, most of the notions about homogeneous spaces and Iwasawa decompositions that are needed. Explicit matricial decompositions are given for every Lie algebra that will be used in the thesis: sl(2,R), so(1,n), so(2,n), sl(2,C) and sp(2,R).
Field propagation in the Schwarzschild-de Sitter black hole
Abdalla, Elcio; Saa, A
2003-01-01
We present an exhaustive analysis of scalar, electromagnetic and gravitational perturbations in the background of a Schwarzchild-de Sitter spacetime. The field propagation is considered by means of a semi-analytical (WKB) approach and two numerical schemes: the characteristic and general initial value integrations. The results are compared near the extreme regime, and a unifying picture is established for the dynamics of different spin fields. Although some of the results just confirm usual expectations, a few surprises turn out to appear, as the dependence on the non-characteristic initial conditions of the non-vanishing asymptotic value for l=0 mode scalar fields.
Cosmological solutions of massive gravity on de Sitter
Langlois, David
2012-01-01
In the framework of the recently proposed models of massive gravity, but defined with respect to a de Sitter reference metric, we obtain new homogeneous and isotropic solutions for arbitrary spatial curvature. These solutions can be classified into three branches. In the first two, the massive gravity terms behave like a cosmological constant. In the third branch, the massive gravity effects can be described by a time evolving effective fluid with rather remarkable features, including the property to behave as a cosmological constant at low energy, when the Hubble parameter decreases below a critical value.
Inflation in de Sitter spacetime and CMB large scales anomaly
Zhao, Dong; Wang, Ping; Chang, Zhe
2014-01-01
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 fitting to explore the cosmological parameters space by using the CosmoMC package with the recently released Planck TT and WMAP Polarization datasets. Using the results from global fitting, we compute a new CMB temperature-temperature spectrum. The obtained TT spectrum has lower power compared with the one based on $\\Lambda$CDM model at large scales.
Geometric Origin of Stokes Phenomenon for de Sitter Radiation
Kim, Sang Pyo
2013-01-01
We propose a geometric interpretation for the Stokes phenomenon in de Sitter spacetime that particles are produced in even dimensions but not in odd dimensions. The scattering amplitude for a quantum field between the in-vacuum and the transported one along a closed path in the complex-time plane gives the particle-production rate that explains not only the Boltzmann factor from the simple pole at infinity, corresponding to the cosmological horizon, but also the sinusoidal behavior from simple poles at the north and south poles of the Euclidean geometry. The Stokes phenomenon is a consequence of interference among four independent closed paths in the complex plane.
Entropy of Reissner-Nordstr\\"om-de Sitter black hole
Zhang, Li-Chun; Ma, Meng-Sen
2016-01-01
Based on the consideration that the black hole horizon and the cosmological horizon of Reissner-Nordstr\\"om black hole in de Sitter space are not independent each other, we conjecture the total entropy of the system should have an extra term contributed from the entanglement between the two horizons, except for the sum of the two horizon entropies. Making use of the globally effective first law and the effective thermodynamic quantities, we derive the total entropy and find that it will diverge as the two horizons tends to coincide.
Modeling and control of an agile tail-sitter aircraft
WANG, XINHUA; Chen, Zengqiang; Yuan, Zhuzhi
2015-01-01
This paper presents a model of an agile tail-sitter aircraft, which can operate as a helicopter as well as capable of transition to fixed-wing flight. Aerodynamics of the co-axial counter-rotating propellers with quad rotors are analysed under the condition that the co-axial is operated at equal rotor torque (power). A finite-time convergent observer based on Lyapunov function is presented to estimate the unknown nonlinear terms in co-axial counter-rotating propellers, the uncertainties and e...
On de Sitter-like and Minkowski-like spacetimes
Energy Technology Data Exchange (ETDEWEB)
Luebbe, Christian; Kroon, Juan Antonio Valiente, E-mail: c.luebbe@qmul.ac.u, E-mail: j.a.valiente-kroon@qmul.ac.u [Queen Mary University of London, School of Mathematical Sciences, Mile End Road, London E1 4NS (United Kingdom)
2009-07-21
Friedrich's proofs for the global existence results of de Sitter-like spacetimes and of semi-global existence of Minkowski-like spacetimes (Friedrich 1986 Commun. Math. Phys. 107 587) are re-examined and discussed, making use of the extended conformal field equations and a gauge based on conformal geodesics. In this gauge, the location of the conformal boundary of the spacetimes is known a priori once the initial data have been prescribed. Thus, it provides an analysis which is conceptually and calculationally simpler.
On a de Sitter-like spacetime with cylindrical symmetry
Culetu, Hristu
2013-01-01
A curved static de Sitter-like metric is analyzed. The source of curvature is rooted from a constant stress tensor with positive energy density and negative pressures. All the curvature invariants are constant everywhere and the geometry is conformally flat. The horizon surface gravity equals the parameter $\\omega$ from the metric that is also interpreted as an angular velocity. The Tolman-Komar gravitational energy is investigated. One finds that the horizon entropy satisfies the relation $S = A_{H}/4$, as for the black hole horizon.
Belokogne, Andrei; Queva, Julien
2016-01-01
By considering Hadamard vacuum states, we first construct the two-point functions associated with Stueckelberg massive electromagnetism in de Sitter and anti-de Sitter spacetimes. Then, from the general formalism developed in [A. Belokogne and A. Folacci, Phys. Rev. D \\textbf{93}, 044063 (2016)], we obtain an exact analytical expression for the vacuum expectation value of the renormalized stress-energy tensor of the massive vector field propagating in these maximally symmetric spacetimes.
Charged gravastars admitting conformal motion
Usmani, A A; Ray, Saibal; Nandi, K K; Kuhfittig, Peter K F; Rakib, Sk A; Hasan, Z
2010-01-01
We propose a new model of a {\\it gravastar} admitting conformal motion. While retaining the framework of the Mazur-Mottola model, the gravastar is assumed to be internally charged, with an exterior defined by a Reissner-Nordstr{\\"o}m rather than a Schwarzschild line element. The solutions obtained involve (i) the interior region, (ii) the shell, and (iii) the exterior region of the sphere. Of these three cases the first case is of primary interest since the total gravitational mass vanishes for vanishing charge and turns the total gravitational mass into an {\\it electromagnetic mass} under certain conditions. This suggests that the interior de Sitter vacuum of a charged gravastar is essentially an electromagnetic mass model that must generate the gravitational mass. We have also analyzed various other aspects such as the stress energy tensor in the thin shell and the entropy of the system.
Time Dependent Couplings as Observables in de Sitter Space
Kitamoto, Hiroyuki
2014-01-01
We summarize and expand our investigations concerning the soft graviton effects on microscopic matter dynamics in de Sitter space. The physical couplings receive IR logarithmic corrections which are sensitive to the IR cut-off at the one-loop level. The scale invariant spectrum in the gravitational propagator at the super-horizon scale is the source of the de Sitter symmetry breaking. The quartic scalar, Yukawa and gauge couplings become time dependent and diminish with time. In contrast, the Newton's constant increases with time. We clarify the physical mechanism behind these effects in terms of the conformal mode dynamics in analogy with 2d quantum gravity. We show that they are the inevitable consequence of the general covariance and lead to gauge invariant predictions. We construct a simple model in which the cosmological constant is self-tuned to vanish due to UV-IR mixing effect. We also discuss phenomenological implications such as decaying Dark Energy and SUSY breaking at the Inflation era. The quantu...
de Sitter Space in Non-Critical String Theory
Energy Technology Data Exchange (ETDEWEB)
Silverstein, Eva M
2002-08-13
Supercritical string theories in D > 10 dimensions with no moduli are described, generalizing the asymmetric orientifold construction of one of the authors [1]. By taking the number of dimensions to be large and turning on fluxes, dilaton potentials are generated with nontrivial minima at arbitrarily small cosmological constant and D-dimensional string coupling, separated by a barrier from a flat-space linear dilaton region, but possibly suffering from strong coupling problems. The general issue of the decay of a de Sitter vacuum to flat space is discussed. For relatively small barriers, such decays are described by gravitational instantons. It is shown that for a sufficiently large potential barrier, the bubble wall crosses the horizon. At the same time the instanton decay time exceeds the Poincare recurrence time. It is argued that the inclusion of such instantons is neither physically meaningful nor consistent with basic principles such as causality. This raises the possibility that such de Sitter vacua are effectively stable. In the case of the supercritical flux models, decays to the linear dilaton region can be forbidden by such large barriers, but decays to lower flux vacua including AdS minima nevertheless proceed consistently with this criterion. These models provide concrete examples in which cosmological constant reduction by flux relaxation can be explored.
Surviving in a Metastable de Sitter Space-Time
Kashyap, Sitender Pratap; Sen, Ashoke; Verma, Mritunjay
2015-01-01
In a metastable de Sitter space any object has a finite life expectancy beyond which it undergoes vacuum decay. However, by spreading into different parts of the universe which will fall out of causal contact of each other in future, a civilization can increase its collective life expectancy, defined as the average time after which the last settlement disappears due to vacuum decay. We study in detail the collective life expectancy of two comoving objects in de Sitter space as a function of the initial separation, the horizon radius and the vacuum decay rate. We find that even with a modest initial separation, the collective life expectancy can reach a value close to the maximum possible value of 1.5 times that of the individual object if the decay rate is less than 1% of the expansion rate. Our analysis can be generalized to any number of objects, general trajectories not necessarily at rest in the comoving coordinates and general FRW space-time. As part of our analysis we find that in the current state of t...
A note on entropy of de Sitter black holes
Energy Technology Data Exchange (ETDEWEB)
Bhattacharya, Sourav [University of Crete, ITCP and Department of Physics, Heraklion (Greece); Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune (India)
2016-03-15
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. (orig.)
Schwinger effect and backreaction in de Sitter spacetime
Directory of Open Access Journals (Sweden)
Clément Stahl
2016-09-01
Full Text Available 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.
Phantom Accretion onto the Schwarzschild de-Sitter Black Hole
Institute of Scientific and Technical Information of China (English)
M Sharif; G Abbas
2011-01-01
We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole. The energy flux conservation, relativistic Bernoulli equation and mass Bux conservation equation are formulated to discuss the phantom accretion. We discuss the conditions for critical accretion. It is found that the mass of the black hole decreases due to phantom accretion. There exist two critical points which lie in the exterior of horizons (black hole and cosmological horizons). The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking A → 0.%@@ We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole.The energy flux conserva-tion,relativistic Bernoulli equation and mass flux conservation equation are formulated to discuss the phantom accretion.We discuss the conditions for critical accretion.It is found that the mass of the black hole decreases due to phantom accretion.There exist two critical points which lie in the exterior of horizons(black hole and cosmological horizons).The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking ∧→0.
On "dynamical mass" generation in Euclidean de Sitter space
Beneke, M
2012-01-01
We consider the perturbative treatment of the minimally coupled, massless, self-interacting scalar field in Euclidean de Sitter space. Generalizing work of Rajaraman, we obtain the dynamical mass m^2 \\propto sqrt{lambda} H^2 of the scalar for non-vanishing Lagrangian masses and the first perturbative quantum correction in the massless case. We develop the rules of a systematic perturbative expansion, which treats the zero-mode non-perturbatively, and goes in powers of sqrt{lambda}. The infrared divergences are self-regulated by the zero-mode dynamics. Thus, in Euclidean de Sitter space the interacting, massless scalar field is just as well-defined as the massive field. We then show that the dynamical mass can be recovered from the diagrammatic expansion of the self-energy and a consistent solution of the Schwinger-Dyson equation, but requires the summation of a divergent series of loop diagrams of arbitrarily high order. Finally, we note that the value of the long-wavelength mode two-point function in Euclide...
Thermodynamics of Schwarzschild-Beltrami-de Sitter black hole
Liu, Hang; Meng, Xin-He
2017-09-01
In this paper, we investigate the thermodynamical properties of Schwarzschild-Beltrami-de Sitter (S-BdS) black hole introduced by Yan et al. in 2013 by introducing inertial Beltrami coordinates to traditional non-inertial Schwarzschild-de Sitter (S-dS) metric which is the exact static spherical symmetry solution of Einstein equation with a positive cosmological constant Λ. Based on this new metric, we compute entropy on all horizons and we give the entropy bound of the black hole. Hawking temperatures are calculated by considering a perturbation to entropy relations due to that the spacetime described by these inertial coordinates is no longer a stationary spacetime in which surface gravity related to Hawking temperature is defined well on killing horizon. We also get the Smarr relations and the first law of thermodynamics. We find that the S-BdS black hole seems to have similar thermodynamical properties to S-dS black hole in the comparison between their corresponding thermodynamical quantities, although the new black hole metric is described by inertial coordinates which exclude the effects of inertial force.
Coupled bulk and brane fields about a de Sitter brane
Cardoso, A; Mennim, A; Seahra, S S; Wands, D; Cardoso, Antonio; Koyama, Kazuya; Mennim, Andrew; Seahra, Sanjeev S.; Wands, David
2006-01-01
We consider the evolution of a bulk scalar field in anti-de Sitter (AdS) spacetime linearly coupled to a scalar field on a de Sitter boundary brane. We present results of a spectral analysis of the system, and find that the model can exhibit both bound and continuum resonant modes. We find that zero, one, or two bound states may exist, depending upon the masses of the brane and bulk fields relative to the Hubble length and the AdS curvature scale and the coupling strength. In all cases, we find a critical coupling above which there exists a tachyonic bound state. We show how the 5-dimensional spectral results can be interpreted in terms of a 4-dimensional effective theory for the bound states. We find excellent agreement between our analytic results and the results of a new numerical code developed to model the evolution of bulk fields coupled to degrees of freedom on a moving brane. This code can be used to model the behaviour of braneworld cosmological perturbations in scenarios for which no analytic result...
Quintessence and effective RN de Sitter brane geometries
Energy Technology Data Exchange (ETDEWEB)
Pandey, K.P.; Singh, Abhishek K.; Singh, Sunita; Kapoor, Richa; Kar, Supriya [University of Delhi, Department of Physics and Astrophysics, New Delhi (India)
2014-11-15
We revisit the effective space-time torsion curvature in a second order formalism, underlying the non-linear U(1) gauge dynamics, of a two form on a D4-brane. The formalism incorporates a significant global NS two form into the theory via its perturbative coupling to a dynamical two form. In particular we explore the non-linear gauge dynamics on a D{sub 4}-brane in the presence of a non-trivial background metric. An effective de Sitter universe is shown to emerge on a vacuum created pair of (D anti D){sub 3}-branes by a local two form at the past horizon with the Big Bang. We obtain a number of 4D de Sitter quantum black holes with and without a propagating torsion. In a low energy limit the non-perturbative correction may be seen to be insignificant. The quantum black hole undergoes an expansion in the limit and identifies with the Einstein vacuum. Interestingly our analysis reveals a plausible quintessence (axion) on an anti-D{sub 3}-brane which may source the dark energy in a D{sub 3}-brane universe. Arguably a brane universe moves away from its anti-brane due to the conjectured repulsive gravity underlying the quintessence. It leads to a growth in the extra fifth dimension between a brane and an anti-brane, which may provide a clue to an accelerating universe as observed in cosmology. (orig.)
Quintessence and effective RN de Sitter brane geometries
Pandey, K Priyabrat; Singh, Sunita; Kapoor, Richa; Kar, Supriya
2014-01-01
We revisit an effective space-time torsion curvature in a second order formalism, underlying the non-linear $U(1)$ gauge dynamics, of a two form on a $D_4$-brane in type IIA superstring theory. The formalism incorporates the significance of a global NS two form into the theory via its perturbative coupling to a dynamical two form. In particular, we explore the non-linear gauge dynamics on a $D_4$-brane in presence of a non-trivial background metric. The fact that the global modes of a NS two form in an open string theory sources the background metric on a $D_4$-brane may hint at the existence of an anti $D_4$-brane in the formalism. An effective de Sitter universe is shown to emerge on a vacuum created pair of $(D{\\bar D})_3$-brane by a local two form at the past horizon with a Big Bang. We obtain a number of 4D de Sitter quantum black holes, including a Reissner-Nordstrom vacuum, with and without a propagating torsion. The quantum black holes are shown to be free from curvature singularity at $r\\rightarrow 0...
Quintessence and effective RN de Sitter brane geometries
Pandey, K. Priyabrat; Singh, Abhishek K.; Singh, Sunita; Kapoor, Richa; Kar, Supriya
2014-11-01
We revisit the effective space-time torsion curvature in a second order formalism, underlying the non-linear gauge dynamics, of a two form on a -brane. The formalism incorporates a significant global NS two form into the theory via its perturbative coupling to a dynamical two form. In particular we explore the non-linear gauge dynamics on a -brane in the presence of a non-trivial background metric. An effective de Sitter universe is shown to emerge on a vacuum created pair of -branes by a local two form at the past horizon with the Big Bang. We obtain a number of de Sitter quantum black holes with and without a propagating torsion. In a low energy limit the non-perturbative correction may be seen to be insignificant. The quantum black hole undergoes an expansion in the limit and identifies with the Einstein vacuum. Interestingly our analysis reveals a plausible quintessence (axion) on an anti--brane which may source the dark energy in a -brane universe. Arguably a brane universe moves away from its anti-brane due to the conjectured repulsive gravity underlying the quintessence. It leads to a growth in the extra fifth dimension between a brane and an anti-brane, which may provide a clue to an accelerating universe as observed in cosmology.
Gravitational theories with stable (anti-)de Sitter backgrounds
Biswas, Tirthabir; Mazumdar, Anupam
2016-01-01
In this article we will construct the most general torsion-free parity-invariant covariant theory of gravity that is free from ghost-like and tachyonic nstabilities around constant curvature space-times in four dimensions. Specifically, this includes the Minkowski, de Sitter and anti-de Sitter backgrounds. We will first argue in details how starting from a general covariant action for the metric one arrives at an "equivalent" action that at most contains terms that are quadratic in curvatures but nevertheless is sufficient for the purpose of studying stability of the original action. We will then briefly discuss how such a "quadratic curvature action" can be decomposed in a covariant formalism into separate sectors involving the tensor, vector and scalar modes of the metric tensor; most of the details of the analysis however, will be presented in an accompanying paper. We will find that only the transverse and trace-less spin-2 graviton with its two helicity states and possibly a spin-0 Brans-Dicke type scala...
Stringy stability of charged dilaton black holes with flat event horizon
Energy Technology Data Exchange (ETDEWEB)
Ong, Yen Chin [National Taiwan Univ., Taipei (Taiwan); Chen, Pisin [National Taiwan Univ., Taipei (Taiwan); SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-01-15
Electrically charged black holes with flat event horizon in anti-de Sitter space have received much attention due to various applications in Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, from modeling the behavior of quark-gluon plasma to superconductor. Critical to the physics on the dual field theory is the fact that when embedded in string theory, black holes in the bulk may become vulnerable to instability caused by brane pair-production. Since dilation arises naturally in the context of string theory, we study the effect of coupling dilation to Maxwell field on the stability of flat charged AdS black holes.
De Sitter en Einstein. ‘Het lijkt mij dat Einstein hier een vergissing begaan heeft’
Directory of Open Access Journals (Sweden)
Jan Guichelaar
2016-10-01
Full Text Available De Sitter and EinsteinWillem de Sitter’s interest in gravity was based on his work on celestial mechanics, in particular on the four big moons of Jupiter. His work on cosmology was based on the general theory of relativity of Albert Einstein. De Sitter published in 1917, on request of Arthur Eddington to inform the English astronomers, a series of four articles in The Observatory and the Monthly Notices of the Royal Astronomical Society. Einstein developed his own cosmological models, containing mass. De Sitter found a different solution and described a universe without mass. Einstein could not accept De Sitter’s model and they ‘fought out’ two controversies in their correspondence. In theend Einstein had to confess De Sitter was mainly right in his criticisms. In 1932 Einstein and De Sitter published an article on a new model, the so-called Einstein-De Sitter Model of the universe. So, De Sitter was able to do fundamental work in classical celestial mechanics as well as in the new cosmological theories.
Energy Distribution in Reissner-Nordstrom anti-de Sitter black holes in Moller Prescription
Salti, M; Salti, Mustafa; Aydogdu, Oktay
2006-01-01
The energy (due to matter plus fields including gravity) distribution of the Reissner-Nordstr\\"{o}m anti-de Sitter (RN AdS) black holes is studied by using the M{\\o}ller energy-momentum definition in general relativity. This result is compered with the energy expression obtained by using the Einstein and Tolman complexes. Total energy depends on the black hole mass $M$ and charge $Q$ and cosmological constant $\\Lambda$. Energy distribution of the RN AdS is also calculated by using the M{\\o}ller prescription in teleparallel gravity. We get the same result for both of these different gravitation theories. The energy obtained is also independent of the teleparallel dimensionless coupling constant, which means that it is valid not only in the teleparallel equivalent of general relativity, but also in any teleparallel model. Under special cases of our model, we also discuss the energy distributions associated with the Schwarzschild AdS, RN and Schwarzschild black holes, respectively.
Induced fermionic currents in de Sitter spacetime in the presence of a compactified cosmic string
Mohammadi, A; Saharian, A A
2014-01-01
We investigate the vacuum fermionic currents in the geometry of a compactified cosmic string on background of de Sitter spacetime. The currents are induced by magnetic fluxes running along the cosmic string and enclosed by the compact dimension. We show that the vacuum charge and the radial component of the current density vanish. By using the Abel-Plana summation formula, the azimuthal and axial currents are explicitly decomposed into two parts: the first one corresponds to the geometry of a straight cosmic string and the second one is induced by the compactification of the string along its axis. For the axial current the first part vanishes and the corresponding topological part is an even periodic function of the magnetic flux along the string axis and an odd periodic function of the flux enclosed by the compact dimension with the periods equal to the flux quantum. The azimuthal current density is an odd periodic function of the flux along the string axis and an even periodic function of the flux enclosed ...
Critical phenomena of regular black holes in anti-de Sitter space-time
Fan, Zhong-Ying
2016-01-01
In General Relativity coupled to a non-linear electromagnetic field, together with a negative cosmological constant, we obtain the general static spherical symmetric black hole solution with magnetic charges, which is asymptotic to anti-de Sitter (AdS) space-times. In particular, for a degenerate case the solution becomes a Hayward-AdS black hole, which is regular everywhere in the full space-time. The existence of such a regular black hole solution preserves the weak energy condition while the strong energy condition is violated. We then derive the first law and the Smarr formula of the black hole solution. We further discuss its thermodynamic properties and study the critical phenomena in the extended phase space where the cosmological constant is treated as a thermodynamic variable as well as the parameter associated with the non-linear electrodynamics. We obtain many interesting results such as: the Maxwell's equal area law in the $P-V$ (or $S-T$) diagram is violated and consequently the critical point $(...
Li, Ran; Zhao, Junkun
2016-01-01
Reissner-Nordstr\\"om 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 growin...
Charged thin-shell gravastars in noncommutative geometry
Övgün, Ali; Banerjee, Ayan; Jusufi, Kimet
2017-08-01
In this paper we construct a charged thin-shell gravastar model within the context of noncommutative geometry. To do so, we choose the interior of the nonsingular de Sitter spacetime with an exterior charged noncommutative solution by cut-and-paste technique and apply the generalized junction conditions. We then investigate the stability of a charged thin-shell gravastar under linear perturbations around the static equilibrium solutions as well as the thermodynamical stability of the charged gravastar. We find the stability regions, by choosing appropriate parameter values, located sufficiently close to the event horizon.
A Conserved Energy Integral for Perturbation Equations in the Kerr-de Sitter Geometry
Umetsu, H
2000-01-01
The analytic proof of mode stability of the Kerr black hole was provided by Whiting. In his proof, the construction of a conserved quantity for unstable mode was crucial. We extend the method of the analysis for the Kerr-de Sitter geometry. The perturbation equations of massless fields in the Kerr-de Sitter geometry can be transformed into Heun's equations which have four regular singularities. In this paper we investigate differential and integral transformations of solutions of the equations. Using those we construct a conserved quantity for unstable modes in the Kerr-de Sitter geometry, and discuss its property.
The de Sitter limit of inflation and non-linear perturbation theory
DEFF Research Database (Denmark)
Jarnhus, Philip; Sloth, Martin Snoager
2008-01-01
We study the fourth order action of the comoving curvature perturbation in an inflationary universe in order to understand more systematically the de Sitter limit in nonlinear cosmological perturbation theory. We derive the action of the curvature perturbation to fourth order in the comoving gaug......, and show that it vanishes sufficiently fast in the de Sitter limit. By studying the de Sitter limit, we then extrapolate to the n'th order action of the comoving curvature perturbation and discuss the slow-roll order of the n-point correlation function....
Realistic f(T) model describing the de Sitter epoch of the dark energy dominated universe
Nassur, S B; Rodrigues, M E; Houndjo, M J S; Tossa, J
2015-01-01
We consider an exponential model within the so-called f(T) theory of gravity, where $T$ denotes the torsion scalar. We focus our work on a cosmological feature of such a model, checking whether it may describe the de Sitter stage of the current universe through the analysis of the redshift z. Our results shows that the model reproduces the de Sitter stage only for low-redshifts, where the perturbation function goes toward zero as the low values of the redshift are reached, whereas the effective parameter of equation of state goes to -1, which is the expected behavior for any model able to reproduce de Sitter stage.
Open quantum system approach to the Gibbons-Hawking effect of de Sitter space-time.
Yu, Hongwei
2011-02-11
We analyze, in the paradigm of open quantum systems, the reduced dynamics of a freely falling two-level detector in de Sitter space-time in weak interaction with a reservoir of fluctuating quantized conformal scalar fields in the de Sitter-invariant vacuum. We find that the detector is asymptotically driven to a thermal state at the Gibbons-Hawking temperature, regardless of its initial state. Our discussion, therefore, shows that the Gibbons-Hawking effect of de Sitter space-time can be understood as a manifestation of thermalization phenomena that involves decoherence and dissipation in open quantum systems.
The de Sitter limit of inflation and non-linear perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Jarnhus, Philip R; Sloth, Martin S, E-mail: pjarn@phys.au.dk, E-mail: sloth@phys.au.dk [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)
2008-02-15
We study the fourth-order action of the comoving curvature perturbation in an inflationary universe in order to understand more systematically the de Sitter limit in non-linear cosmological perturbation theory. We derive the action of the curvature perturbation to fourth order in the comoving gauge, and show that it vanishes sufficiently fast in the de Sitter limit. By studying the de Sitter limit, we then extrapolate to the nth-order action of the comoving curvature perturbation and discuss the slow-roll order of the n-point correlation function.
The evolution of unstable black holes in anti-de Sitter space
Gubser, S S; Gubser, Steven S.; Mitra, Indrajit
2001-01-01
We examine the thermodynamic stability of large black holes in four-dimensional anti-de Sitter space, and we demonstrate numerically that black holes which lack local thermodynamic stability often also lack stability against small perturbations. This shows that no-hair theorems do not apply in anti-de Sitter space. A heuristic argument, based on thermodynamics only, suggests that if there are any violations of Cosmic Censorship in the evolution of unstable black holes in anti-de Sitter space, they are beyond the reach of a perturbative analysis.
Graviton Loop Corrections to Vacuum Polarization in de Sitter in a General Covariant Gauge
Glavan, D; Prokopec, Tomislav; Woodard, R P
2015-01-01
We evaluate the one-graviton loop contribution to the vacuum polarization on de Sitter background in a 1-parameter family of exact, de Sitter invariant gauges. Our result is computed using dimensional regularization and fully renormalized with BPHZ counterterms, which must include a noninvariant owing to the time-ordered interactions. Because the graviton propagator engenders a physical breaking of de Sitter invariance two structure functions are needed to express the result. In addition to its relevance for the gauge issue this is the first time a covariant gauge graviton propagator has been used to compute a noncoincident loop. A number of identities are derived which should facilitate further graviton loop computations.
Dias, G A S; Dias, Goncalo A. S.; Lemos, Jose' P. S.
2006-01-01
A calculation of the entropy of static, electrically charged, black holes with spherical, toroidal, and hyperbolic compact and oriented horizons, in D spacetime dimensions, is performed. These black holes live in an anti-de Sitter spacetime, i.e., a spacetime with negative cosmological constant. To find the entropy, the approach developed by Solodukhin is followed. The method consists in a redefinition of the variables in the metric, by considering the radial coordinate as a scalar field. Then one performs a 2+(D-2) dimensional reduction, where the (D-2) dimensions are in the angular coordinates, obtaining a 2-dimensional effective scalar field theory. This theory is a conformal theory in an infinitesimally small vicinity of the horizon. The corresponding conformal symmetry will then have conserved charges, associated with its infinitesimal conformal generators, which will generate a classical Poisson algebra of the Virasoro type. Shifting the charges and replacing Poisson brackets by commutators, one recover...
Anti-de Sitter Space as Topological Insulator and Holography
Ho, Shih-Hao
2012-01-01
We argue that the Anti-de Sitter (AdS) space can be thought as a topological insulator with a co-dimensional one defect living at the UV boundary. Combining the bulk/edge correspondence for the topological insulators and the AdS/CFT correspondence, the fermionic topological phases for the dual conformal field theories (CFTs) can then be classified in the same way as classifying the topological phases of the massive free fermions in the co-dimensional one higher Minkowski spaces. The latter can then be obtained in Kitaev's framework of the K-theory analysis in classifying the topological insulators/superconductors. Our framework provides a way of classifying the symmetry-protected topologically ordered phases for the strongly interacting gapless systems, of which the classification is intractable in the context of strongly correlated condensed matters devised mainly for gapped systems.
Geodesics in the (anti-)de Sitter spacetime
Tho, Nguyen Phuc Ky
2016-01-01
A class of exact solutions of the geodesic equations in (anti-)de Sitter spacetimes is presented. The geodesics for test particles in $AdS_4$ and $dS_4$ spacetimes are respectively sinusoidal and hyperbolic sine world lines. The world line for light rays is straight lines as known. The world lines of test particles are not dependent on their energy as noted. Spontaneous symmetry breaking of $AdS_4$ spacetime provides a physical explanation for arising of the virtual particle and antiparticle pairs in the vacuum. Interestingly, the energy of a pair and the time its particles moving along their geodesics can be related by a relation similar to Heisenberg uncertainty one pertaining quantum vacuum fluctuations. The sinusoidal geodesics of $AdS_4$ spacetime can describe the world lines of the virtual particles and antiparticles. The hyperbolic sine geodesics of $dS_4$ spacetime can explain why galaxies move apart with positive accelerations.
Quantum statistical entropy for Kerr-de Sitter black hole
Institute of Scientific and Technical Information of China (English)
Zhang Li-Chun; Wu Yue-Qin; Zhao Ren
2004-01-01
Improving the membrane model by which the entropy of the black hole is studied, we study the entropy of the black hole in the non-thermal equilibrium state. To give the problem stated here widespread meaning, we discuss the (n+2)-dimensional de Sitter spacetime. Through discussion, we obtain that the black hole's entropy which contains two horizons (a black hole's horizon and a cosmological horizon) in the non-thermal equilibrium state comprises the entropy corresponding to the black hole's horizon and the entropy corresponding to the cosmological horizon. Furthermore, the entropy of the black hole is a natural property of the black hole. The entropy is irrelevant to the radiation field out of the horizon. This deepens the understanding of the relationship between black hole's entropy and horizon's area. A way to study the bosonic and fermionic entropy of the black hole in high non-thermal equilibrium spacetime is given.
De Sitter Space, Interacting Quantum Field Theory And Alpha Vacua
Goldstein, K
2005-01-01
Inspired by recent evidence for a positive cosmological constant, this thesis considers some of the implications of trying to incorporate approximately seventy percent of the universe, namely dark energy, consistently into quantum field theory on a curved background. Such considerations may have implications for inflation, the understanding of dark energy at the present time and finally the challenging topic of trying to incorporate a positive cosmological constant into string theory. We will mainly examine various aspects of the one parameter family of de Sitter invariant states—the so called α-vacua. On the phenomenological side, not only could such states provide a window into trans-planckian physics through their imprint on the cosmological microwave background (CMB), but they may also be a source of ultra-high energy cosmic rays (UHECR) at the present time. From a purely theoretical perspective, formulating interacting quantum field theory in these states is a challenging problem whic...
Energy in the Schwarzschild-de Sitter Spacetime
Salti, M; Aydogdu, Oktay; Salti, Mustafa
2006-01-01
The energy (due to matter and fields including gravitation) of the Schwarzschild-de Sitter spacetime is investigated by using the Moller energy-momentum definition in both general relativity and teleparallel gravity. We found the same energy distribution for a given metric in both of these different gravitation theories. It is also independent of the teleparallel dimensionless coupling constant, which means that it is valid in any teleparallel model. Our results sustain that (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime and (b) the viewpoint of Lessner that the Moller energy-momentum complex is a powerful concept of energy and momentum.
Black hole remnant in asymptotic anti-de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Wen, Wen-Yu [Chung Yuan Christian University, Department of Physics, Center for High Energy Physics, Chung Li City (China); National Taiwan University, Leung Center for Cosmology and Particle Astrophysics, Taipei (China); Wu, Shang-Yu [National Chiao Tung University, Department of Electrophysics, Hsinchu (China)
2015-12-15
The solution of a remnant was suggested for the black hole ground state after surface gravity is corrected for the loop quantum effect. On the other hand, a Schwarzschild black hole in asymptotic anti-de Sitter space would tunnel into the thermal soliton solution known as the Hawking-Page phase transition. In this letter, we investigate the low temperature phase of a three-dimensional Banados-Teitelboim-Zanelli (BTZ) black hole and four-dimensional AdS Schwarzschild black hole. We find that the thermal soliton is energetically favored rather than the remnant solution at low temperature in three dimensions, while a Planck-size remnant is still possible in four dimensions. Though the BTZ remnant seems energetically disfavored, we argue that it is still possible to find in the overcooled phase if strings were present, and its implication is discussed. (orig.)
Black hole remnant in asymptotic anti-de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Wen, Wen-Yu, E-mail: steve.wen@gmail.com [Department of Physics, Center for High Energy Physics, Chung Yuan Christian University, Chung Li City, Taiwan (China); Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, 106, Taipei, Taiwan (China); Wu, Shang-Yu, E-mail: loganwu@gmail.com [Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan (China)
2015-12-21
The solution of a remnant was suggested for the black hole ground state after surface gravity is corrected for the loop quantum effect. On the other hand, a Schwarzschild black hole in asymptotic anti-de Sitter space would tunnel into the thermal soliton solution known as the Hawking–Page phase transition. In this letter, we investigate the low temperature phase of a three-dimensional Banados–Teitelboim–Zanelli (BTZ) black hole and four-dimensional AdS Schwarzschild black hole. We find that the thermal soliton is energetically favored rather than the remnant solution at low temperature in three dimensions, while a Planck-size remnant is still possible in four dimensions. Though the BTZ remnant seems energetically disfavored, we argue that it is still possible to find in the overcooled phase if strings were present, and its implication is discussed.
Effective long wavelength scalar dynamics in de Sitter
Moss, Ian
2016-01-01
We discuss the effective infrared theory governing a light scalar's long wavelength dynamics in de Sitter spacetime. We show how the separation of scales around the physical curvature radius $k/a \\sim H$ can be performed consistently with a window function and how short wavelengths can be integrated out in the Schwinger-Keldysh path integral formalism. At leading order, and for time scales $\\Delta t \\gg H^{-1}$, this results in the well-known Starobinsky stochastic evolution. Our approach allows for the computation of quantum UV corrections, generating an effective potential on which the stochastic dynamics takes place, as well as the description of dynamics on spatial and temporal scales comparable to $H^{-1}$ and above. We further elaborate on the use of a Wigner function to evaluate the non-perturbative expectation values of field correlators and the stress-energy tensor of $\\phi$ within the stochastic formalism.
Brane induced supersymmetry breaking and de Sitter supergravity
Energy Technology Data Exchange (ETDEWEB)
Bandos, Igor [Department of Theoretical Physics, University of the Basque Country UPV/EHU, P.O. Box 644, 48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain); Martucci, Luca [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova (Italy); I.N.F.N. Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy); Sorokin, Dmitri [I.N.F.N. Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy); Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova (Italy); Tonin, Mario [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova (Italy); I.N.F.N. Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy)
2016-02-12
We obtain a four-dimensional supergravity with spontaneously broken supersymmetry 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.
Effective potential and Goldstone bosons in de Sitter space
Arai, Takashi
2013-01-01
We investigate nonperturbative infrared effects for the O(N) linear sigma model in de Sitter space using the two-particle irreducible effective action at the Hartree truncation level. This approximation resums the infinite series of so-called superdaisy diagrams. For the proper treatment of ultraviolet divergences, we first study the renormalization of this approximation on a general curved background. Then, we calculate radiatively corrected masses and the effective potential. As a result, spontaneous symmetry breaking is possible, on the other hand, the Goldstone modes acquire a positive definite mass term due to the screening effects of interaction. Possible infrared divergence is self-regulated by the mass term. Furthermore, there is a symmetry restoring phase transition as a function of the Hubble parameter. In our approximation, the phase transition is of first order.
Energy, momentum and angular momentum conservations in de Sitter gravity
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.
Revisiting constraints on uplifts to de Sitter vacua
Bizet, Nana Cabo
2016-01-01
We revisit the issue of uplifting the potential to de Sitter (dS) vacua in type IIB flux compactifications of Kachru, Kallosh, Linde and Trivedi (KKLT). We shed light on some tension between two constraints on dS vacua in type IIB string theory. One is the well-known and much-discussed constraint which leads to the no-go theorem that can in principle be evaded. The other follows from 4-dimensional Einstein's equations, which has, however, been much less discussed in connection with the former constraint. In addition to the challenges previously posed, it is suggested that the uplifting scenarios, in particular, obstruct the evasion of the no-go theorem more strongly than one might have assumed.
Kinks in two-dimensional Anti-de Sitter Space
Barnes, J L; ter Veldhuis, T; Webster, M J
2009-01-01
Soliton solutions in scalar field theory defined on a two-dimensional Anti-de Sitter background space-time are investigated. It is shown that the lowest soliton excitation generically has frequency equal to the inverse radius of the space-time. Analytic and numerical soliton solutions are determined in "phi to the fourth" scalar field theory with a negative mass-squared. The classical soliton mass is calculated as a function of the ratio of the square of the mass scale of the field theory over the curvature of the space-time. For the case that this ratio equals unity, the soliton excitation spectrum is determined algebraically and the one-loop radiative correction to the soliton mass is computed in the semi-classical approximation.
Dynamics of black holes in de Sitter spacetimes
Zilhao, Miguel; Gualtieri, Leonardo; Herdeiro, Carlos; Sperhake, Ulrich; Witek, Helvi
2012-01-01
Nonlinear dynamics in cosmological backgrounds has the potential to teach us immensely about our universe, and also to serve as prototype for nonlinear processes in generic curved spacetimes. Here we report on dynamical evolutions of black holes in asymptotically de Sitter spacetimes. We focus on the head-on collision of equal mass binaries and for the first time compare analytical and perturbative methods with full blown nonlinear simulations. Our results include an accurate determination of the merger/scatter transition (consequence of an expanding background) for small mass binaries and a test of the Cosmic Censorship conjecture, for large mass binaries. We observe that, even starting from small separations, black holes in large mass binaries eventually lose causal contact, in agreement with the conjecture.
Simple generalizations of anti-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Magueijo, Joao; Mozaffari, Ali, E-mail: ali.mozaffari@imperial.ac.u [Theoretical Physics, Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)
2010-07-07
We consider new cosmological solutions which generalize the cosmological patch of the anti-de Sitter (AdS) spacetime, allowing for fluids with equations of state such that w {ne} -1. We use them to derive the associated full manifolds. We find that these solutions can all be embedded in flat five-dimensional spacetime with -- + + + signature, revealing deformed hyperboloids. The topology and some aspects of the causal structure of these spaces are therefore unchanged, and closed time-like curves are identified, before a covering space is considered. However the structure of Killing vector fields is entirely different and so we may expect a different structure of Killing horizons in these solutions.
Scalar field breathers on anti-de Sitter background
Fodor, Gyula; Grandclément, Philippe
2013-01-01
We study spatially localized, time-periodic solutions (breathers) of scalar field theories with various self-interacting potentials on Anti-de Sitter (AdS) spacetimes in $D$ dimensions. A detailed numerical study of spherically symmetric configurations in $D=3$ dimensions is carried out, revealing a rich and complex structure of the phase-space (bifurcations, resonances). Scalar breather solutions form one-parameter families parametrized by their amplitude, $\\varepsilon$, while their frequency, $\\omega=\\omega(\\varepsilon)$, is a function of the amplitude. The scalar breathers on AdS we find have a small amplitude limit, tending to the eigenfunctions of the linear Klein-Gordon operator on AdS. Importantly most of these breathers appear to be generically stable under time evolution.
One-photon pair production on de Sitter spacetime
Blaga, Robert
2015-01-01
We study the one-photon scalar pair production QED process on the expanding de Sitter spacetime. Using perturbation theory, we obtain the transition probability and study its properties as a function of the expansion parameter $\\omega$. On flat space the process is forbidden by energy-momentum conservation. It is expected that for a dynamical background there is an energy exchange correlate to the strength of the gravitational field. We use momentum space plots and compute the mean production angle to illustrate this. We show that the mean angle grows with $\\omega$, but also find that in the flat limit the fall-off is unexpectedly slow. To investigate this further we obtain the probability around different angular configuration, at leading order in $m/\\omega$, and find that the $\\omega$ dependence at small angles is very weak. We comment on the possible astrophysical implications.
Polarized vector bosons on the de Sitter expanding universe
Cotaescu, Ion I
2009-01-01
The quantum theory of the vector field minimally coupled to the gravity of the de Sitter spacetime is built in a canonical manner starting with a new complete set of quantum modes of given momentum and helicity in the moving chart of conformal time. It is shown that the canonical quantization leads to new vector propagators which differ from the two-point functions proposed by Allen and Jacobson [{\\em Commun. Math. Phys.} {\\bf 103} (1986) 669] and Tsamis and Woodard [{\\em J.Math.Phys.} {\\bf 48} (2007) 052306]. The one-particle operators are also written down pointing out that their properties are similar with those found already in the quantum theory of the scalar, Dirac and Maxwell free fields.
Renormalization group approach to scalar quantum electrodynamics on de Sitter
González, Francisco Fabián
2016-01-01
We consider the quantum loop effects in scalar electrodynamics on de Sitter space by making use of the functional renormalization group approach. We first integrate out the photon field, which can be done exactly to leading (zeroth) order in the gradients of the scalar field, thereby making this method suitable for investigating the dynamics of the infrared sector of the theory. Assuming that the scalar remains light we then apply the functional renormalization group methods to the resulting effective scalar theory and focus on investigating the effective potential, which is the leading order contribution in the gradient expansion of the effective action. We find symmetry restoration at a critical renormalization scale $\\kappa=\\kappa_{\\rm cr}$ much below the Hubble scale $H$. When compared with the results of Serreau and Guilleux [arXiv:1306.3846 [hep-th], arXiv:1506.06183 [hep-th
Entanglement entropy of α-vacua in de Sitter space
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.
Entanglement entropy of $\\alpha$-vacua in de Sitter space
Kanno, Sugumi; Shock, Jonathan P; Soda, Jiro
2014-01-01
We consider the entanglement entropy of a free massive scalar field in the one parameter family of $\\alpha$-vacua in de Sitter space by using a method developed by Maldacena and Pimentel. An $\\alpha$-vacuum can be thought of as a state filled with particles from the point of view of the Bunch-Davies vacuum. Of all the $\\alpha$-vacua we find that the entanglement entropy takes the minimal value in the Bunch-Davies solution. We also calculate the asymptotic value of the R\\'enyi entropy and find that it increases as $\\alpha$ increases. We argue these feature stem from pair condensation within the non-trivial $\\alpha$-vacua where the pairs have an intrinsic quantum correlation.
De Sitter space in gauge/gravity duality
Directory of Open Access Journals (Sweden)
Lilia Anguelova
2015-10-01
Full Text Available 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 (AdS4 spacetime. Finally, we comment on the implications of our dS4 solutions for building gravity duals of Glueball Inflation.
De Sitter space in gauge/gravity duality
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.
De Sitter Space in Gauge/Gravity Duality
Anguelova, Lilia; Wijewardhana, L C Rohana
2014-01-01
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 dS_4 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 dS_4 solutions for building gravity duals of Glueball Inflation.
Surviving in a metastable de Sitter space-time
Energy Technology Data Exchange (ETDEWEB)
Kashyap, Sitender Pratap; Mondal, Swapnamay [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); Sen, Ashoke [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); School of Physics, Korea Institute for Advanced Study,Seoul 130-722 (Korea, Republic of); Verma, Mritunjay [Harish-Chandra Research Institute,Chhatnag Road, Jhusi, Allahabad 211019 (India); International Centre for Theoretical Sciences,Malleshwaram, Bengaluru 560 012 (India)
2015-09-21
In a metastable de Sitter space any object has a finite life expectancy beyond which it undergoes vacuum decay. However, by spreading into different parts of the universe which will fall out of causal contact of each other in future, a civilization can increase its collective life expectancy, defined as the average time after which the last settlement disappears due to vacuum decay. We study in detail the collective life expectancy of two comoving objects in de Sitter space as a function of the initial separation, the horizon radius and the vacuum decay rate. We find that even with a modest initial separation, the collective life expectancy can reach a value close to the maximum possible value of 1.5 times that of the individual object if the decay rate is less than 1% of the expansion rate. Our analysis can be generalized to any number of objects, general trajectories not necessarily at rest in the comoving coordinates and general FRW space-time. As part of our analysis we find that in the current state of the universe dominated by matter and cosmological constant, the vacuum decay rate is increasing as a function of time due to accelerated expansion of the volume of the past light cone. Present decay rate is about 3.7 times larger than the average decay rate in the past and the final decay rate in the cosmological constant dominated epoch will be about 56 times larger than the average decay rate in the past. This considerably weakens the lower bound on the half-life of our universe based on its current age.
Do scale-invariant fluctuations imply the breaking of de Sitter invariance?
Energy Technology Data Exchange (ETDEWEB)
Youssef, A., E-mail: youssef@mathematik.hu-berlin.de [Institut fuer Mathematik und Institut fuer Physik, Humboldt-Universitaet zu Berlin, Johann von Neumann-Haus, Rudower Chaussee 25, 12489 Berlin (Germany)
2013-01-08
The quantization of the massless minimally coupled (mmc) scalar field in de Sitter spacetime is known to be a non-trivial problem due to the appearance of strong infrared (IR) effects. In particular, the scale-invariance of the CMB power-spectrum - certainly one of the most successful predictions of modern cosmology - is widely believed to be inconsistent with a de Sitter invariant mmc two-point function. Using a Cesaro-summability technique to properly define an otherwise divergent Fourier transform, we show in this Letter that de Sitter symmetry breaking is not a necessary consequence of the scale-invariant fluctuation spectrum. We also generalize our result to the tachyonic scalar fields, i.e. the discrete series of representations of the de Sitter group, that suffer from similar strong IR effects.
Kapteyn and de Sitter; a rare and special teacher-student and coach-player relationship
de Sitter, Wolter Reinold
Measured along the yardstick of subsequent success, Willem de Sitter [1872-1934] was one of Kapteyn's foremost pupils along with van Rhijn, Schilt and Jan Hendrik Oort. From his appointment as professor at Leiden University in 1908 until Kapteyn's death in 1922, de Sitter maintained in close contact with his teacher. Kapteyn was his trusted sounding board and consultant in scientific and administrative matters, as well as academic politics. De Sitter had his ideas on a complete reorganisation and restructuring of Leiden Observatory scrutinized by Kapteyn's experienced judgement, and together they developed ideas and completed a plan of action, including touchy staffing, salary and budgettary aspects. Together they were a formidable team and operated as such. Notes by de Sitter and many letters from Kapteyn illustrate their fruitful relationship.
Physical meaning of the conserved quantities on anti-de Sitter geodesics
Cotǎescu, Ion I.
2017-05-01
The geodesic motion on anti-de Sitter spacetimes is studied, pointing out how the trajectories are determined by the ten independent conserved quantities associated with the specific S O (2 ,3 ) isometries of these manifolds. The new result is that there are two conserved S O (3 ) vectors which play the same role as the Runge-Lenz vector of the Kepler problem, determining the major and minor semiaxes of the ellipsoidal anti-de Sitter geodesics.
Quantum Linear Gravity in de Sitter Universe on Gupta-Bleuler Vacuum State
Enayati, M.; Takook, M. V.; Rouhani, S.
2017-04-01
Application of Krein space quantization to the linear gravity in de Sitter space-time have constructed on Gupta-Bleuler vacuum state, resulting in removal of infrared divergence and preserving de Sitter covariant. By pursuing this path, the non uniqueness of vacuum expectation value of the product of field operators in curved space-time disappears as well. Then the vacuum expectation value of the product of field operators can be defined properly and uniquely.
De Sitter ground state of scalar-tensor gravity and its primordial perturbation
Zhang, Hongsheng
2010-01-01
We find an exact de Sitter solution of scalar-tensor gravity, in which the non-minimal coupling scalar is rolling along a non-constant potential. We investigated its primordial quantum perturbation around the adiabatic vacuum. We put forward for the first time that exact de Sitter generates non-exactly scale invariant perturbations. In the conformal coupling case, this model predicts that the tensor mode of the perturbation (gravity wave) is strongly depressed.
Every timelike geodesic in anti--de Sitter spacetime is a circle of the same radius
Sokołowski, Leszek M
2016-01-01
We refine and analytically prove an old proposition due to Calabi and Markus on the shape of timelike geodesics of anti--de Sitter space in the ambient flat space. We prove that each timelike geodesic forms in the ambient space a circle of the radius determined by $\\Lambda$, lying on a Euclidean two--plane. Then we outline an alternative proof for $AdS_4$. We also make a comment on the shape of timelike geodesics in de Sitter space.
Guha, Sarbari; Bhattacharya, Pinaki
2010-01-01
In this paper, we have studied the timelike and null geodesics in the vicinity of a non-rotating, charged black hole in a five-dimensional Reissner-Nordstrom Anti-de Sitter spacetime. Here the solutions are uniquely characterized by their mass, charge and the cosmological constant. The line element and the horizon function has been defined and it is found that only one horizon is physically admissible. The spherical symmetry of the geometry helps us to reduce the problem to a study of three geodesic equations. In our analysis, we have used both the method of effective Newtonian orbit calculations and the dynamical systems method to analyze the particle trajectories. The equation of motion of a particle of unit mass is found. The effective potential under which any test particle moves with a given angular momentum at a given distance from the black hole, depends only on the mass and charge of the black hole and the cosmological constant. This equation is used to study radial motion and the corresponding stabil...
Hydrodynamics of R-charged black holes
Son, D T; Son, Dam T.; Starinets, Andrei O.
2006-01-01
We consider hydrodynamics of N=4 supersymmetric SU(N_c) Yang-Mills plasma at a nonzero density of R-charge. In the regime of large N_c and large 't Hooft coupling the gravity dual description involves an asymptotically Anti- de Sitter five-dimensional charged black hole solution of Behrnd, Cvetic and Sabra. We compute the shear viscosity as a function of chemical potentials conjugated to the three U(1) \\subset SO(6)_R charges. The ratio of the shear viscosity to entropy density is independent of the chemical potentials and is equal to 1/4\\pi. For a single charge black hole we also compute the thermal conductivity, and investigate the critical behavior of the transport coefficients near the boundary of thermodynamic stability.
On asymptotic flatness and Lorentz charges
Energy Technology Data Exchange (ETDEWEB)
Compere, Geoffrey [KdV Institute for Mathematics, Universiteit van Amsterdam (Netherlands); Dehouck, Francois; Virmani, Amitabh, E-mail: gcompere@uva.nl, E-mail: fdehouck@ulb.ac.be, E-mail: avirmani@ulb.ac.be [Physique Theorique et Mathematique, Universite Libre de Bruxelles, Bruxelles (Belgium)
2011-07-21
In this paper we establish two results concerning four-dimensional asymptotically flat spacetimes at spatial infinity. First, we show that the six conserved Lorentz charges are encoded in two unique, distinct, but mutually dual symmetric divergence-free tensors that we construct from the equations of motion. Second, we show that the integrability of Einstein's equations in the asymptotic expansion is sufficient to establish the equivalence between counter-term charges defined from the variational principle and charges defined by Ashtekar and Hansen. These results clarify earlier constructions of conserved charges in the hyperboloid representation of spatial infinity. In showing this, the parity condition on the mass aspect is not needed. Along the way in establishing these results, we prove two lemmas on tensor fields on three-dimensional de Sitter spacetime stated by Ashtekar-Hansen and Beig-Schmidt and state and prove three additional lemmas.
Mobile app for human-interaction with sitter robots
Das, Sumit Kumar; Sahu, Ankita; Popa, Dan O.
2017-05-01
Human environments are often unstructured and unpredictable, thus making the autonomous operation of robots in such environments is very difficult. Despite many remaining challenges in perception, learning, and manipulation, more and more studies involving assistive robots have been carried out in recent years. In hospital environments, and in particular in patient rooms, there are well-established practices with respect to the type of furniture, patient services, and schedule of interventions. As a result, adding a robot into semi-structured hospital environments is an easier problem to tackle, with results that could have positive benefits to the quality of patient care and the help that robots can offer to nursing staff. When working in a healthcare facility, robots need to interact with patients and nurses through Human-Machine Interfaces (HMIs) that are intuitive to use, they should maintain awareness of surroundings, and offer safety guarantees for humans. While fully autonomous operation for robots is not yet technically feasible, direct teleoperation control of the robot would also be extremely cumbersome, as it requires expert user skills, and levels of concentration not available to many patients. Therefore, in our current study we present a traded control scheme, in which the robot and human both perform expert tasks. The human-robot communication and control scheme is realized through a mobile tablet app that can be customized for robot sitters in hospital environments. The role of the mobile app is to augment the verbal commands given to a robot through natural speech, camera and other native interfaces, while providing failure mode recovery options for users. Our app can access video feed and sensor data from robots, assist the user with decision making during pick and place operations, monitor the user health over time, and provides conversational dialogue during sitting sessions. In this paper, we present the software and hardware framework that
Quantum loop corrections of charged dS black hole
Naji, J
2016-01-01
In this paper, a charged black hole in de Sitter space considered and logarithmic corrected entropy used to study thermodynamics. Logarithmic corrections of entropy comes from thermal fluctuations which plays role of quantum loop corrections. In that case we are able to study the effect of quantum loop on the black hole thermodynamics and statistics. As black hole is a gravitational object, so it helps to obtain some information about the quantum gravity.
Holography and quantum states in elliptic de Sitter space
Halpern, Illan F
2015-01-01
We outline a program for interpreting the higher-spin dS/CFT model in terms of physics in the causal patch of a dS observer. The proposal is formulated in "elliptic" de Sitter space dS_4/Z_2, obtained by identifying antipodal points in dS_4. We discuss recent evidence that the higher-spin model is especially well-suited for this, since the antipodal symmetry of bulk solutions has a simple encoding on the boundary. For context, we test some other (free and interacting) theories for the same property. Next, we analyze the notion of quantum field states in the non-time-orientable dS_4/Z_2. We compare the physics seen by different observers, with the outcome depending on whether they share an arrow of time. Finally, we implement the marriage between higher-spin holography and observers in dS_4/Z_2, in the limit of free bulk fields. We succeed in deriving an observer's operator algebra and Hamiltonian from the CFT, but not her S-matrix. We speculate on the extension of this to interacting higher-spin theory.
A note on entropy of de Sitter black holes
Bhattacharya, Sourav
2015-01-01
A de Sitter black hole or a black hole spacetime endowed with a positive cosmological constant has two Killing horizons -- a black hole horizon 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 first use a suitable general geometric set up for 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 the horizons in an equal footing and to obtain the total entropy. We show that in order get the total entropy, the near horizon mode functions for the diffeomorphism generating vector fields has to be restricted in a certain manner, compared to the single horizon spacetimes. We nex...
Coupled boundary and bulk fields in anti-de Sitter
Koyama, K; Wands, D; Koyama, Kazuya; Mennim, Andrew; Wands, David
2005-01-01
We investigate the dynamics of a boundary field coupled to a bulk field with a linear coupling in an anti-de Sitter bulk spacetime bounded by a Minkowski (Randall-Sundrum) brane. An instability criterion for the coupled boundary and bulk system is found. There exists a tachyonic bound state when the coupling is above a critical value, determined by the masses of the brane and bulk fields and AdS curvature scale. This bound state is normalizable and localised near the brane, and leads to a tachonic instability of the system on large scales. Below the critical coupling, there is no tachyonic state and no bound state. Instead, we find quasi-normal modes which describe stable oscillations, but with a finite decay time. Only if the coupling is tuned to the critical value does there exist a massless stable bound state, as in the case of zero coupling for massless fields. We discuss the relation to gravitational perturbations in the Randall-Sundrum brane-world.
The fate of monsters in anti-de Sitter spacetime
Ong, Yen Chin; Chen, Pisin
2013-07-01
Black hole entropy remains a deep puzzle: where does such enormous amount of entropy come from? Curiously, there exist gravitational configurations that possess even larger entropy than a black hole of the same mass, in fact, arbitrarily high entropy. These are the so-called monsters, which are problematic to the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence paradigm since there is far insufficient degrees of freedom on the field theory side to account for the enormous entropy of monsters in AdS bulk. The physics of the bulk however may be considerably modified at semi-classical level due to the presence of branes. We show that this is especially so since monster spacetimes are unstable due to brane nucleation. As a consequence, it is not clear what the final fate of monsters is. We argue that in some cases there is no real threat from monsters since although they are solutions to Einstein's Field Equations, they are very likely to be completely unstable when embedded in string theory, and thus probably are not solutions to the full quantum theory of gravity. Our analysis, while suggestive and supportive of the claim that such pathological objects are not allowed in the final theory, by itself does not rule out all monsters. We comment on various kin of monsters such as the "bag-of-gold" spacetime, and also discuss briefly the implications of our work to some puzzles related to black hole entropy.
Black rings in global anti-de Sitter space
Figueras, Pau
2014-01-01
We construct five dimensional black rings in global anti-de Sitter space using numerical methods. These rings satisfy the BPS bound $| J | < M \\ell$, but the angular velocity always violates the Hawking-Reall bound $| \\Omega_H \\ell | \\leq 1$, indicating that they should be unstable under superradiance. At high temperatures, the limit $| \\Omega_H \\ell | \\searrow 1$ is attained by thin rings with an arbitrarily large radius. However, at sufficiently low temperatures, this limit is saturated by a new kind of rings, whose outer circle can still be arbitrarily long while the hole in the middle does not grow proportionally. This gives rise to a membrane-like horizon geometry, which does not have an asymptotically flat counterpart. We find no evidence for thin AdS black rings whose transverse $S^2$ is much larger than the radius of AdS, $\\ell$, and thus these solutions never fall into the hydrodynamic regime of the dual CFT. Thermodynamically, we find that AdS black rings never dominate the grand canonical ensemb...
New class of de Sitter vacua in string theory compactifications
Achúcarro, Ana; Ortiz, Pablo; Sousa, Kepa
2016-10-01
String theory contains few known working examples of de Sitter vacua, four-dimensional universes with a positive cosmological constant. A notorious obstacle is the stabilization of a large number—sometimes hundreds—of moduli fields that characterize the compact dimensions. We study the stability of a class of supersymmetric moduli (the complex structure moduli and dilaton in type-IIB flux compactifications) in the regime where the volume of the compact space is large but not exponentially large. We show that, if the number of moduli is very large, random matrix theory provides a new stability condition, a lower bound on the volume. We find a new class of stable vacua where the mass spectrum of these supersymmetric moduli is gapped, without requiring a large mass hierarchy between moduli sectors or any fine-tuning of the superpotential. We provide the first explicit example of this class of vacua in the P[1,1 ,1 ,6 ,9 ] 4 model. A distinguishing feature is that all fermions in the supersymmetric sector are lighter than the gravitino.
A de Sitter tachyon thick braneworld and gravity localization
German, Gabriel; Malagon-Morejon, Dagoberto; Mora-Luna, Refugio Rigel; da Rocha, Roldao
2013-01-01
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 one that involves a tachyonic bulk scalar field. In this framework we study a thick braneworld with a cosmological background induced on the brane. It turns out that the field equations derived from the model with a warped 5D geometry are highly non-linear equations that admit a non-trivial solution for the warp factor and the tachyon scalar field with 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. However, 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 manage to obtain such a thick brane configuration in this tachyon-gravity setup. When analyzing th...
Critical phenomena of regular black holes in anti-de Sitter space-time
Energy Technology Data Exchange (ETDEWEB)
Fan, Zhong-Ying [Peking University, Center for High Energy Physics, Beijing (China)
2017-04-15
In General Relativity, addressing coupling to a non-linear electromagnetic field, together with a negative cosmological constant, we obtain the general static spherical symmetric black hole solution with magnetic charges, which is asymptotic to anti-de Sitter (AdS) space-times. In particular, for a degenerate case the solution becomes a Hayward-AdS black hole, which is regular everywhere in the full space-time. The existence of such a regular black hole solution preserves the weak energy condition, while the strong energy condition is violated. We then derive the first law and the Smarr formula of the black hole solution. We further discuss its thermodynamic properties and study the critical phenomena in the extended phase space where the cosmological constant is treated as a thermodynamic variable as well as the parameter associated with the non-linear electrodynamics. We obtain many interesting results such as: the Maxwell equal area law in the P-V (or S-T) diagram is violated and consequently the critical point (T{sub *},P{sub *}) of the first order small-large black hole transition does not coincide with the inflection point (T{sub c},P{sub c}) of the isotherms; the Clapeyron equation describing the coexistence curve of the Van der Waals (vdW) fluid is no longer valid; the heat capacity at constant pressure is finite at the critical point; the various exponents near the critical point are also different from those of the vdW fluid. (orig.)
Phases of R-charged Black Holes, Spinning Branes and Strongly Coupled Gauge Theories
Cvetic, M; Cvetic, Mirjam; Gubser, Steven S.
1999-01-01
We study the thermodynamic stability of charged black holes in gauged supergravity theories in D=5, D=4 and D=7. We find explicitly the location of the Hawking-Page phase transition between charged black holes and the pure anti-de Sitter space-time, both in the grand-canonical ensemble, where electric potentials are held fixed, and in the canonical ensemble, where total charges are held fixed. We also find the explicit local thermodynamic stability constraints for black holes with one non-zero charge. In the grand-canonical ensemble, there is in general a region of phase space where neither the anti-de Sitter space-time is dynamically preferred, nor are the charged black holes thermodynamically stable. But in the canonical ensemble, anti-de Sitter space-time is always dynamically preferred in the domain where black holes are unstable. We demonstrate the equivalence of large R-charged black holes in D=5, D=4 and D=7 with spinning near-extreme D3-, M2- and M5-branes, respectively. The mass, the charges and the ...
On the Instability of Global de Sitter Space to Particle Creation
Anderson, Paul R
2013-01-01
We show that global de Sitter space is unstable to particle creation, even for a massive free field theory with no self-interactions. The O(4,1) de Sitter invariant state is a definite phase coherent superposition of particle and anti-particle solutions in both the asymptotic past and future, and therefore is not a true vacuum state. In the closely related case of particle creation by a constant, uniform electric field, a time symmetric state analogous to the de Sitter invariant one is constructed, which is also not a stable vacuum state. We provide the general framework necessary to describe the particle creation process, the mean particle number, and dynamical quantities such as the energy-momentum tensor and current of the created particles in both the de Sitter and electric field backgrounds in real time, establishing the connection to kinetic theory. We compute the energy-momentum tensor for adiabatic vacuum states in de Sitter space initialized at early times in global S^3 sections, and show that partic...
Castles in the Air: The Einstein-De Sitter Debate, 1916-1918
Midwinter, Charles; Janssen, Michel
2011-03-01
The Einstein De Sitter debate marked the birth of modern cosmology and the infamous cosmological constant. For Einstein, the controversy was essentially a philosophical one. Einstein's insistence on a static Universe and Mach's Principle guided him in the construction of his own cosmological model, and compelled him to criticize De Sitter's. For De Sitter, the debate began as idle conjecture. Before long, however, he began to wonder if the "spacious castles" he and Einstein had constructed might actually represent physical reality. We plan to write a volume that reproduces the documents relevant to the debate. Our commentary will retrace and explain the arguments of the historical players, complete with calculations. For the first time readers will be able to follow the arguments of Einstein and De Sitter in a detailed exploration of the first two relativistic cosmological models. Readers will see how Einstein's flawed criticisms of De Sitter were supported by Herman Weyl, and finally how Felix Klein settled the whole matter with a coordinate transformation.
Thermodynamics of $(d+1)$-dimensional NUT-charged AdS Spacetimes
Clarkson, R.; Fatibene, L.; Mann, R. B.
2002-01-01
We consider the thermodynamic properties of $(d+1)$-dimensional spacetimes with NUT charges. Such spacetimes are asymptotically locally anti de Sitter (or flat), with non-trivial topology in their spatial sections, and can have fixed point sets of the Euclidean time symmetry that are either $(d-1)$-dimensional (called "bolts") or of lower dimensionality (pure "NUTs"). We compute the free energy, conserved mass, and entropy for 4, 6, 8 and 10 dimensions for each, using both Noether charge meth...
Efficacy of the "baby-sitter" procedure after prolonged denervation.
Mersa, B; Tiangco, D A; Terzis, J K
2000-01-01
This study was undertaken to evaluate whether 40 percent of the hypoglossal nerve, which showed optimal efficacy in restoring orbicularis oculi muscle (OOM) function after different percentages of partial neurectomy in a previous study would be effective after prolonged denervation time. Twenty Sprague-Dawley rats were divided into four groups. In first-stage surgery the left facial nerve of all animals was transected at the level of the stylomastoid foramen and main zygomatic branch. Group A (controls) consisted of animals with only left facial nerves transected (no repair). In Groups B, C, and D the facial nerve was transected and the facial musculature was denervated for a period of 4, 8, and 12 weeks respectively. During a second-stage procedure, a 40 percent neurectomy was performed on the hypoglossal nerve. Subsequently, a nerve transfer was performed by coaptations of a saphenous nerve graft to the neurectomized hypoglossal nerve and the main zygomatic branch of the facial nerve that innervated the OOM. Behavioral analysis of blink reflex, electrophysiology, and axon and motor end-plate counts in Groups B, C, and D showed superior results compared to Group A. There was no statistically significant difference observed among Groups B, C, and D (p > 0.05). Despite the diminished number of axons in the zygomatic branch and motor end-plates in the orbicularis oculi muscle after 12 weeks of denervation, there was still sufficient muscle target recovery to effect some eye closure in all groups except the controls. This study demonstrated in this model that the 40 percent partial neurectomy of the XII to VII component of the "baby-sitter" procedure was effective even after prolonged denervation.
Detecting the Curvature of de Sitter Universe with Two Entangled Atoms
Tian, Zehua; Jing, Jiliang; Dragan, Andrzej
2016-01-01
We show that two entangled atoms can be used to detect spacetime curvature with their resonance Casimir- Polder interaction (RCPI). Spacetime curvature modifies the vacuum fluctuation of quantum fields and thus affects the interatomic interaction via the coupling between atoms and quantum fields. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature that also affects the thermal temperature felt by the static observer. Interestingly, the RCPI of the same setup embedded in a thermal bath in the Minkowski universe is independent of its temperature. Therefore, although a single static atom in the de Sitter-invariant vacuum behaves the same as the one bathed in a thermal Minkowski universe, using the distinct difference between RCPI of two entangled atoms, one can in principle distinguish these two universes.
The Critical Phenomena and Thermodynamics of the Reissner-Nordstrom-de Sitter Black Hole
Directory of Open Access Journals (Sweden)
Ren Zhao
2014-01-01
Full Text Available It is wellknown that there are two horizons for the Reissner-Nordstrom-de Sitter spacetime, namely, the black hole horizon and the cosmological one. Both horizons can usually seem to be two independent thermodynamic systems; however, the thermodynamic quantities on both horizons satisfy the laws of black hole thermodynamics and are not independent. In this paper by considering the relations between the two horizons we give the effective thermodynamic quantities in Reissner-Nordstrom-de Sitter spacetime. The thermodynamic properties of these effective quantities are analyzed; moreover, the critical temperature, critical pressure, and critical volume are obtained. We also discussed the thermodynamic stability of Reissner-Nordstrom-de Sitter spacetime.
On de Sitter solutions in asymptotically safe $f(R)$ theories
Falls, Kevin; Nikolakopoulos, Kostas; Rahmede, Christoph
2016-01-01
The availability of scaling solutions in renormalisation group improved versions of cosmology are investigated in the high-energy limit. We adopt $f(R)$-type models of quantum gravity which display an interacting ultraviolet fixed point at shortest distances. Expanding the gravitational fixed point action to very high order in the curvature scalar, we detect a convergence-limiting singularity in the complex field plane. Resummation techniques including Pad\\'e approximants as well as infinite order approximations of the effective action are used to maximise the domain of validity. We find that the theory displays near de Sitter solutions as well as an anti-de Sitter solution in the UV whereas real de Sitter solutions, for small curvature, appear to be absent. The significance of our results for inflation, and implications for more general models of quantum gravity are discussed.
Monotone-short solutions of the Tolman-Oppenheimer-Volkoff-de Sitter equation
Hsu, Cheng-Hsiung; Makino, Tetu
2016-09-01
It is known that spherically symmetric static solutions of the Einstein equations with a positive cosmological constant for the energy-momentum tensor of a barotropic perfect fluid are governed by the Tolman-Oppenheimer-Volkoff-de Sitter equation. Some sufficient conditions for the existence of monotone-short solutions (with finite radii) of the equation are given in this article. Then we show that the interior metric can extend to the exterior Schwarzschild-de Sitter metric on the exterior vacuum region with twice continuous differentiability. In addition, we investigate the analytic property of the solutions at the vacuum boundary. Our result (Theorem 1) can be considered as the de Sitter version of the result by Rendall and Schmidt [Classical Quantum Gravity 8, 985-1000 (1991)]. Furthermore, one can see that there are different properties of the solutions with those of the Tolman-Oppenheimer-Volkoff equation (with zero cosmological constant) in certain situation.
Quantum Fluctuations for de Sitter Branes in Bulk AdS(5)
Naylor, W; Naylor, Wade; Sasaki, Misao
2004-01-01
The vacuum expectation value of the square of the field fluctuations of a scalar field on a background consisting of two de Sitter branes embedded in an anti-de Sitter bulk are considered. We apply a dimensional reduction to obtain an effective lower dimensional de Sitter space equation of motion with associated Kaluza-Klein masses and canonical commutation relations. The case of a scalar field obeying a restricted class of mass and curvature couplings, including massless, conformal coupling as a special case, is considered. We find that the local behaviour of the quantum fluctuations suffers from surface divergences as we approach the brane, however, if the field is {\\it constrained} to its value on the brane from the beginning then surface divergences disappear. The ratio of $$ between the Kaluza-Klein spectrum and the lowest eigenvalue mode is found to vanish in the limit that one of the branes goes to infinity.
Covariant Quantization of "Massive" Spin-3/2 Fields in the de Sitter Space
Takook, M V; Babaian, E
2012-01-01
We present a covariant quantization of the free "massive" spin-3/2 fields in four-dimensional de Sitter space-time based on analyticity in the complexified pseudo-Riemannian manifold. The field equation is obtained as an eigenvalue equation of the Casimir operator of the de Sitter group. The solutions are calculated in terms of coordinate-independent de Sitter plane-waves in tube domains and the null curvature limit is discussed. We give the group theoretical content of the field equation. The Wightman two-point function $S^{i \\bar j}_{\\alpha\\alpha'}(x,x')$ is calculated. We introduce the spinor-vector field operator $\\Psi_\\alpha(f)$ and the Hilbert space structure. A coordinate-independent formula for the field operator $\\Psi_\\alpha(x)$ is also presented.
Why Boltzmann Brains Don't Fluctuate Into Existence From the De Sitter Vacuum
Boddy, Kimberly K; Pollack, Jason
2015-01-01
Many modern cosmological scenarios feature large volumes of spacetime in a de Sitter vacuum phase. Such models are said to be faced with a "Boltzmann Brain problem" - the overwhelming majority of observers with fixed local conditions are random fluctuations in the de Sitter vacuum, rather than arising via thermodynamically sensible evolution from a low-entropy past. We argue that this worry can be straightforwardly avoided in the Many-Worlds (Everett) approach to quantum mechanics, as long as the underlying Hilbert space is infinite-dimensional. In that case, de Sitter settles into a truly stationary quantum vacuum state. While there would be a nonzero probability for observing Boltzmann-Brain-like fluctuations in such a state, "observation" refers to a specific kind of dynamical process that does not occur in the vacuum (which is, after all, time-independent). Observers are necessarily out-of-equilibrium physical systems, which are absent in the vacuum. Hence, the fact that projection operators corresponding...
CFT description of three-dimensional Kerr-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Fjelstad, Jens E-mail: jens.fjelstad@kau.se; Hwang, Stephen E-mail: stephen.hwang@kau.se; Maansson, Teresia E-mail: teresia@physto.se
2002-10-07
We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space.
A preferred ground state for the scalar field in de Sitter space
Aslanbeigi, Siavash; Buck, Michel
2013-01-01
We investigate a recent proposal for a distinguished vacuum state of a free scalar quantum field in an arbitrarily curved spacetime, known as the Sorkin-Johnston (SJ) vacuum, by applying it to de Sitter space. We derive the associated two-point functions on both the global and Poincar\\'e (cosmological) patches in general d+1 dimensions. In all cases where it is defined, the SJ vacuum belongs to the family of de Sitter invariant alpha-vacua. We obtain different states depending on the spacetim...
In–out propagator in de Sitter space from general boundary quantum field theory
Directory of Open Access Journals (Sweden)
Daniele Colosi
2015-09-01
Full Text Available The general boundary formulation of quantum theory is applied to quantize a real massive scalar field in de Sitter space. The space–time region where the dynamics of the field takes place is bounded by one spacelike hypersurface of constant conformal de Sitter time. The computation of the amplitude in the presence of a linear interaction with a source field with compact support in the region considered provides the expression of the Feynman propagator which coincides with the so-called in–out propagator.
Super-de Sitter and alternative super-Poincar\\'e symmetries
Tolstoy, V N
2016-01-01
It is well-known that de Sitter Lie algebra $\\mathfrak{o}(1,4)$ contrary to anti-de Sitter one $\\mathfrak{o}(2,3)$ does not have a standard $\\mathbb{Z}_2$-graded superextension. We show here that the Lie algebra $\\mathfrak{o}(1,4)$ has a superextension based on the $\\mathbb{Z}_2\\times\\mathbb{Z}_2$-grading. Using the standard contraction procedure for this superextension we obtain an {\\it alternative} super-Poincar\\'e algebra with the $\\mathbb{Z}_2\\times\\mathbb{Z}_2$-grading.
Global solutions of Yang-Mills equations on anti-de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Choquet-Bruhat, Y. (Paris Univ. (France). Mecanique Relativiste)
1989-12-01
Anti-de Sitter spacetime is a C{sup {infinity}} manifold diffeomorphic to R{sup 4}, endowed with a C{sup {infinity}} metric of hyperbolic signature. However this spacetime is not globally hyperbolic, and the known results about the solution of the Cauchy problem for wave equations on Lorentzian manifolds do not apply, even for a small interval of time and even for linear equations. We prove the global existence of a solution of the Cauchy problem for the Yang-Mills-Higgs equations on anti-de Sitter spacetime, under the condition that there is no radiation at timelike infinity, a condition that is explained mathematically. (author).
Slipher's redshifts as support for de Sitter's model and the discovery of the dynamic universe
Nussbaumer, Harry
2013-01-01
Of the first two relativistiv world models, only the one by de Sitter predicted redshifted spectra from far away astronomical objects. Slipher's redshifts therefore seemed to arbitrate against Einstein's model which made no such predictions. Both models were trying to describe a static universe. However, Lemaitre found that de Sitter's construct resulted in a spatially inhomogeneous universe. He then opted for a model that correspondes to Einstein's closed, curved universe but allowed the radius of curvature to change with time. Slipher's redshifts suggested to him that the universe is dynamic and expanding. We also discuss the respective merits of Friedman and Lemaitre in revealing the dynamic nature of the universe.
Gravitationally induced adiabatic particle production: from big bang to de Sitter
de Haro, Jaume; Pan, Supriya
2016-08-01
In the background of a flat homogeneous and isotropic space-time, we consider a scenario of the Universe driven by the gravitationally induced ‘adiabatic’ particle production with constant creation rate. We have shown that this Universe attains a big bang singularity in the past and at late-time it asymptotically becomes de Sitter. To clarify this model Universe, we performed a dynamical analysis and found that the Universe attains a thermodynamic equilibrium in this late de Sitter phase. Finally, for the first time, we have discussed the possible effects of ‘adiabatic’ particle creations in the context of loop quantum cosmology.
Phase space localization for anti-de Sitter quantum mechanics and its zero curvature limit
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.
Detecting the Curvature of de Sitter Universe with Two Entangled Atoms
Zehua Tian; Jieci Wang; Jiliang Jing; Andrzej Dragan
2016-01-01
Casimir-Polder interaction arises from the vacuum fluctuations of quantum field that depend on spacetime curvature and thus is spacetime-dependent. Here we show how to use the resonance Casimir-Polder interaction (RCPI) between two entangled atoms to detect spacetime curvature. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature relevant to the temperature felt by the static observer. It is characterized by a $1/L^...
Kerr-AdS analogue of tricritical point and solid/liquid/gas phase transition
Altamirano, Natacha; Mann, Robert B; Sherkatghanad, Zeinab
2013-01-01
We study the thermodynamic behavior of multi-spinning d=6 Kerr-anti de Sitter black holes in the canonical ensemble of fixed angular momenta J1 and J2. We find, dependent on the ratio q=J2/J1, qualitatively different interesting phenomena known from the `every day thermodynamics' of simple substances. For q=0 the system exhibits recently observed reentrant large/small/large black hole phase transitions, but for 00.0985 we observe the `standard liquid/gas behavior' of the Van der Waals fluid.
Thermodynamic analysis of universes with the initial and final de-Sitter eras
Moradpour, H; Ghasemi, A
2015-01-01
Our aim is studying the thermodynamics of cosmological models including initial and final de-Sitter eras. For this propose, bearing Cai-Kim temperature in mind, we investigate the thermodynamic properties of a dark energy candidate with variable energy density, and show that the state parameter of this dark energy candidate should obey the $\\omega_D\
Hadamard renormalized scalar field theory on anti-de Sitter space-time
Kent, Carl
2014-01-01
We consider a real massive free quantum scalar field with arbitrary curvature coupling on $n$-dimensional anti-de Sitter space-time. We use Hadamard renormalization to find the vacuum expectation values of the quadratic field fluctuations and the stress-energy tensor, presenting explicit results for $n=2$ to $n=11$ inclusive.
Semiclassical relations and IR effects in de Sitter and slow-roll space-times
DEFF Research Database (Denmark)
B. Giddings, Steven; Sloth, Martin Snoager
2010-01-01
We calculate IR divergent graviton one-loop corrections to scalar correlators in de Sitter space, and show that the leading IR contribution may be reproduced via simple semiclassical consistency relations. One can likewise use such semiclassical relations to calculate leading IR corrections to co...
A sufficient condition for de Sitter vacua in type IIB string theory
Energy Technology Data Exchange (ETDEWEB)
Rummel, Markus [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2011-07-15
We derive a sufficient condition for realizing meta-stable de Sitter vacua with small positive cosmological constant within type IIB string theory flux compactifications with spontaneously broken supersymmetry. There are a number of 'lamp post' constructions of de Sitter vacua in type IIB string theory and supergravity. We show that one of them - the method of 'Kaehler uplifting' by F-terms from an interplay between non-perturbative effects and the leading {alpha}'-correction - allows for a more general parametric understanding of the existence of de Sitter vacua. The result is a condition on the values of the flux induced superpotential and the topological data of the Calabi-Yau compactification, which guarantees the existence of a meta-stable de Sitter vacuum if met. Our analysis explicitly includes the stabilization of all moduli, i.e. the Kaehler, dilaton and complex structure moduli, by the interplay of the leading perturbative and non-perturbative effects at parametrically large volume. (orig.)
The gauge theory of the de Sitter group and Ashtekar formulation
Nieto, J A; Socorro, J
1994-01-01
By adding the Pontrjagin topological invariant to the gauge theory of the de Sitter group proposed by MacDowell and Mansouri we obtain an action quadratic in the field-strengths, of the Chern-Simons type, from which the Ashtekar formulation is derived.
Strength and genericity of singularities in Tolman-Bondi-de Sitter collapse
Gonçalves, S M C V
2001-01-01
We study the curvature strength and visibility of the central singularity arising in Tolman-Bondi-de Sitter collapse. We find that the singularity is visible and Tipler strong along an infinite number of timelike geodesics, independently of the initial data, and thus stable against perturbations of the latter.
Duffin-Kemmer-Petiau oscillator with Snyder-de Sitter algebra
Falek, M.; Merad, M.; Birkandan, T.
2017-02-01
We present an exact solution of the one-dimensional Bosonic oscillator for spin 1 and spin 0 particles with the Snyder-de Sitter model, where the energy eigenvalues and eigenfunctions are determined for both cases. The wave functions can be given in terms of Gegenbauer polynomials. We also comment on the thermodynamic properties of the system.
Different Approaches for the Einstein Energy Associated with the de Sitter C-Space-time
Salti, M
2005-01-01
The paper is purposed to elaborate the problem of gravitational energy localization in de Sitter(dS) C-space-time (the C space-time in a background with a cosmological constant $\\Lambda$). In this connection, using the energy-momentum definition of Einstein, we find the same energy in both general relativity and tele-parallel gravity.
Hawking radiation from Kerr-Newman de Sitter black hole via anomalies
Institute of Scientific and Technical Information of China (English)
Lin Kai; Yang Shu-Zheng; Zeng Xiao-Xiong
2008-01-01
In this paper, Hawking radiation from the Kerr-Newman de Sitter black hole is studied via gauge anomaly and gravitational anomaly. The obtained results of Hawking radiation from the event horizon and the cosmological horizon accord with those by other methods.
The Sitter Service in Scotland: A Study of the Costs and Benefits. Insight.
Wilson, Valerie; Hall, Stuart; Rankin, Nicola; Davidson, Julia; Schad, Dominic
This report presents the findings of an examination of the costs, benefits, and characteristics of Sitter Services, a program in Scotland offering child care in the child's home to parents working atypical hours or respite care for families of children with developmental disabilities. The study also explored users' and providers' knowledge of the…
The normalized energy eigenspinors of the Dirac field on anti-de Sitter spacetime
Cotaescu, I I
1999-01-01
It is shown how can be derived 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 like in special relativity.
Finite entropy of Schwarzschild anti-de Sitter black hole in different coordinates
Institute of Scientific and Technical Information of China (English)
Ding Chi-Kun; Jing Ji-Liang
2007-01-01
This paper studies the finite statistical-mechanical entropy of the Schwarzschild anti-de Sitter (AdS) spacetime At first glance, it seems that the results would be different from that in the Schwarzschild-like coordinate since both the entropies in these coordinates are exactly equivalent to that in the Schwarzschild-like coordinate.
One-loop Quantum Electrodynamic Correction to the Gravitational Potentials on de Sitter
Wang, C L
2015-01-01
We compute the one loop photon contribution to the graviton self-energy on de Sitter background and use it to solve the linearized Einstein equation for a point mass. Our results show that a co-moving observer sees a logarithmic spatial running Newton's constant. Equivalently a static observer reports a secular suppression of the Newtonian potential.
Late-time quadrupolar gravitational wave power in de Sitter space
Hazboun, Jeffrey
2017-01-01
We have calculated the power emitted by a binary system in a cosmological context modeled by a stress energy source on a de Sitter background. The calculation is based on the quadrupole formula for late-time gravitational waves in de Sitter space put forward by Ashtekar, Bonga and Kesavan. There is little reason to expect, a priori, that the projection operator usually used to find the transverse-traceless components of a tensor in asymptotically flat spaces will accurately characterize the physical degrees of freedom in an asymptotically de Sitter spacetime. Instead we use the differential recipe that is true in general, but cumbersome to solve explicitly. The solution presented is based on a conformally transformed version of the quadrupole moment from a Minkowski spacetime for a stable circular binary. A process for calculating the late time power is presented, which coincides with future null infinity. Progress on time dependent results will also be presented. We will discuss the physicality of these results and compare it to other results for gravitational waves in de Sitter space, including recent results on gravitational wave memory.
Lecture Notes on Turbulent Instability of Anti-de Sitter Spacetime
Maliborski, Maciej
2013-01-01
In these lecture notes we discuss recently conjectured instability of anti-de Sitter space, resulting in gravitational collapse of a large class of arbitrarily small initial perturbations. We uncover the technical details used in the numerical study of spherically symmetric Einstein-massless scalar field system with negative cosmological constant that led to the conjectured instability.
The Booth Sitters of Santa Fe's Indian Market: Making and Maintaining Authenticity
Bernstein, Bruce
2007-01-01
In this article, the author addresses the burden of non-Native expectation on Native artists, highlighting issues of authenticity, creation, and public display. The author writes about the booth sitters hired by collectors to sit--sometimes all night--and wait for the official opening of the annual Indian Market in Santa Fe, New Mexico. He focuses…
Inflation driven by q-de Sitter in light of Planck 2013 and BICEP2 results
Setare, M R; Kamali, V; Myrzakulov, R
2014-01-01
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 $\\phi_{end}$, the spectral index and the associated running of the spectral index are %$ n_\\mathrm{s} - 1 \\sim -2\\epsilon, \\quad \\alpha_\\mathrm{s} \\equiv 0 $. To end the inflation: we should have $q=\\frac{3}{4}$. We deduce that the inflation ends when the evolu...
Evidence for special relativity with de Sitter space-time symmetry
Institute of Scientific and Technical Information of China (English)
闫沐霖
2011-01-01
I show the formulation of de Sitter Special Relativity （dS-SR） based on Dirac-Lu-Zou-Guo’s discussions. dS-SR quantum mechanics is formulated, and the dS-SR Dirac equation for hydrogen is suggested. The equation in the earth-QSO framework reference is sol
Absence of GZK Cutoff and Test of de Sitter Invariant Special Relativity
Institute of Scientific and Technical Information of China (English)
CHANG Zhe; CHEN Shao-Xia; HUANG Chao-Guang
2005-01-01
@@ The possibility that the absence of Greisen-Zatsepin-Kuz'min (GZK) cutoff is used to discriminate between de Sitter invariant special relativity (SRc,R) and general relativity (GR) is studied.A careful investigation shows,unfortunately, that the phenomenon fails to distinguish SRc,R from GR, at least, at classical level.
Quantum Tunneling Radiation of Reissner-Nordstrom de Sitter Black Hole with a Global Monopole
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
Applying Parikh's quantum tunneling model, we study the quantum tunneling radiation of ReissnerNordstrom de Sitter black hole with a global monopole. The result shows that the tunneling rates at the event horizon and the cosmic horizon are related to Bekenstein-Hawking entropy if we take the energy conservation into consideration,and the true radiate spectrum is not precisely thermal.
Toldo, C.
2014-01-01
This thesis is devoted to the analysis of asymptotically Anti-de Sitter (AdS) black holes arising as solutions of theories of gauged Supergravity in four spacetime dimensions. After a brief recap of the main features of gauged supergravity, the first part of the thesis deals with the explicit constr
Inverse scattering at fixed energy in de Sitter-Reissner-Nordstr\\"om black holes
Daudé, Thierry
2010-01-01
In this paper, we consider massless Dirac fields propagating in the outer region of de Sitter-Reissner-Nordstr\\"om black holes. We show that the metric of such black holes is uniquely determined by the partial knowledge of the corresponding scattering matrix $S(\\lambda)$ at a fixed energy $\\lambda \
Phase structure of the Born-Infeld-anti-de Sitter black holes probed by non-local observables
Energy Technology Data Exchange (ETDEWEB)
Zeng, Xiao-Xiong [Chongqing Jiaotong University, School of Material Science and Engineering, Chongqing (China); Chinese Academy of Sciences, Institute of Theoretical Physics, Beijing (China); Liu, Xian-Ming [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA (United States); Hubei University for Nationalities, Center for Theoretical Physics, School of Sciences, Enshi, Hubei (China); Li, Li-Fang [Chinese Academy of Sciences, State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Beijing (China)
2016-11-15
With the non-local observables such as two point correlation function and holographic entanglement entropy, we probe the phase structure of the Born-Infeld-anti-de Sitter black holes. For the case bQ > 0.5, where b is the Born-Infeld parameter and Q is the charge of the black hole, the phase structure is found to be similar to that of the Van der Waals phase transition, namely the black hole undergoes a first order phase transition and a second order phase transition before it reaches a stable phase. While for the case bQ < 0.5, a new phase branch emerges besides the Van der Waals phase transition. For the first order phase transition, the equal area law is checked, and for the second order phase transition, the critical exponent of the heat capacity is obtained. All these results are found to be the same as that observed in the entropy-temperature plane. (orig.)
Directory of Open Access Journals (Sweden)
Ran Li
2016-07-01
Full Text Available 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.
Energy Technology Data Exchange (ETDEWEB)
Li, Ran, E-mail: liran@htu.edu.cn [Department of Physics, Henan Normal University, Xinxiang 453007 (China); Zhang, Hongbao, E-mail: hzhang@vub.ac.be [Department of Physics, Beijing Normal University, Beijing 100875 (China); Theoretische Natuurkunde, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Zhao, Junkun, E-mail: zhaojkun1991@163.com [Department of Physics, Henan Normal University, Xinxiang 453007 (China)
2016-07-10
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.
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
In 1935 Dirac established the physical wave equations in the de-Sitter spaces but neither energy-momentum operators nor their conservative laws were given. In this article it is proved that in the de-Sitter group there is a subgroup group isomorphic to the Heisenberg group and the generators of this groups are the energy-momentum operators which obey a conservative law.
Energy Technology Data Exchange (ETDEWEB)
Tipler, F.J.
1986-02-01
Penrose diagrams including the c boundary at infinity and the singularities for the Einstein, Eddington--Lemaitre, Eddington--Lemaitre--Bondi, and anti-de Sitter universes are constructed. Penrose diagrams for the Einstein, Eddington--Lemaitre, and anti-de Sitter universes have been published before, but these diagrams are incomplete in that the published diagrams do not contain the c-boundary points of the universes they are supposed to represent.
The circular loop equation of a cosmic string with time-varying tension in de Sitter spacetimes
Liu, Yunqi; Cheng, Hongbo(Department of Physics, East China University of Science and Technology, Shanghai 200237, China)
2008-01-01
In this work the equation of circular loops of cosmic string possessing time-dependent tension is studied in the de Sitter spacetime. We find that the cosmic string loops with initial radius $r(t_{0})>0.707L$, L de Sitter radius, should not collapse to form a black holes. It is also found that in the case of $r(t_{0})
On localization of universal scalar fields in a tachyonic de Sitter thick braneworld
Diaz-Furlong, Alfonso; Linares, Roman; Mora-Luna, Refugio Rigel; Morales-Tecotl, Hugo A
2014-01-01
Braneworld models may yield interesting effects ranging from high-energy physics to cosmology, or even some low-energy physics. Their mode structure modifies standard results in these physical realms that can be tested and used to set bounds on the models parameters. Now, to define braneworld deviations from standard 4D physics, a notion of matter and gravity localization on the brane is crucial. In this work we investigate the localization of universal massive scalar fields in a de Sitter thick tachyonic braneworld generated by gravity coupled to a tachyonic bulk scalar field. This braneworld possesses a 4D de Sitter induced metric and is asymptotically flat despite the presence of a negative bulk cosmological constant, a novel and interesting peculiarity that contrasts with previously known models. Universal scalar fields can be localized in this expanding braneworld if their bulk mass obeys an upper bound, otherwise they delocalize: The dynamics of the scalar field is governed by a Schroedinger equation wi...
The global rotating scalar field vacuum on anti-de Sitter space–time
Directory of Open Access Journals (Sweden)
Carl Kent
2015-01-01
Full Text Available We consider the definition of the global vacuum state of a quantum scalar field on n-dimensional anti-de Sitter space–time as seen by an observer rotating about the polar axis. Since positive (or negative frequency scalar field modes must have positive (or negative Klein–Gordon norm respectively, we find that the only sensible choice of positive frequency corresponds to positive frequency as seen by a static observer. This means that the global rotating vacuum is identical to the global nonrotating vacuum. For n≥4, if the angular velocity of the rotating observer is smaller than the inverse of the anti-de Sitter radius of curvature, then modes with positive Klein–Gordon norm also have positive frequency as seen by the rotating observer. We comment on the implications of this result for the construction of global rotating thermal states.
Penrose's quasi-local mass for asymptotically anti-de Sitter space-times
Kelly, Ron
2015-01-01
Penrose's quasi-local mass construction is carried through for two-surfaces at infinity in asymptotically anti-de Sitter space-times. A modification of the Witten argument is given to prove a positivity property of the resulting conserved quantities. [This work formed part of Ron Kelly's Oxford D.Phil. thesis, and the first person pronoun refers to him. It appeared in hand-written form as `Asymptotically anti-de Sitter space-times' in Twistor Newsletter 20 (1985) pp11-23 (available at http://people.maths.ox.ac.uk/lmason/Tn/TN1-25), but is appearing type-set for the first time here. Footnotes marked ${\\bf{PT}}$ have been added for this version by Paul Tod, in the hope of making this work available to a wider audience.
The rotating scalar field vacuum on anti-de Sitter space-time
Kent, Carl
2015-01-01
We consider the definition of the vacuum state of a quantum scalar field on $n$-dimensional anti-de Sitter space-time as seen by an observer rotating about the polar axis. Since positive (or negative) frequency scalar field modes must have positive (or negative) Klein-Gordon norm respectively, we find that the only sensible choice of positive frequency corresponds to positive frequency as seen by a static observer. This means that the rotating vacuum is identical to the nonrotating vacuum. If the angular velocity of the rotating observer is smaller than the inverse of the anti-de Sitter radius of curvature, then modes with positive Klein-Gordon norm also have positive frequency as seen by the rotating observer. We comment on the implications of this result for the construction of rotating thermal states.
Quantum radiation of non-stationary Kerr-Newman-de Sitter black hole
Institute of Scientific and Technical Information of China (English)
Jiang Qing-Quan; Yang Shu-Zheng; Li Hui-Ling
2005-01-01
By introducing a new tortoise coordinate transformation, we investigate the quantum thermal and non-thermal radiations of a non-stationary Kerr-Newman-de Sitter black hole. The accurate location and radiate temperature of the event horizon as well as the maximum energy of the non-thermal radiation are derived. It is shown that the radiate temperature and the maximum energy are related to not only the evaporation rate, but also the shape of the event horizon, moreover the maximum energy depends on the electromagnetic potential. Finally, we use the results to reduce the non-stationary Kerr-Newman black hole, the non-stationary Kerr black hole, the stationary Kerr-Newman-de Sitter black hole, and the static Schwarzshild black hole.
Late-time structure of the Bunch-Davies de Sitter wavefunction
Energy Technology Data Exchange (ETDEWEB)
Anninos, Dionysios [Stanford Institute of Theoretical Physics, Stanford University, Stanford (United States); Anous, Tarek [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge (United States); Freedman, Daniel Z. [Stanford Institute of Theoretical Physics, Stanford University, Stanford (United States); Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge (United States); Department of Mathematics, Massachusetts Institute of Technology, Cambridge (United States); Konstantinidis, George [Stanford Institute of Theoretical Physics, Stanford University, Stanford (United States)
2015-11-30
We examine the late time behavior of the Bunch-Davies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the Bunch-Davies wavefunction. We consider self-interacting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The four-dimensional Fefferman-Graham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunction contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory.
Late-time Structure of the Bunch-Davies De Sitter Wavefunction
Anninos, Dionysios; Freedman, Daniel Z; Konstantinidis, George
2014-01-01
We examine the late time behavior of the Bunch-Davies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the Bunch-Davies wavefunction. We consider self-interacting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The four-dimensional Fefferman-Graham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunction contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory.
Sarkar, Tamal; Bhadra, Arunava
2014-01-01
The late time accelerated expansion of the Universe demands that even in local galactic-scales it is desirable to study astrophysical phenomena, particularly relativistic accretion related phenomena in massive galaxies or in galaxy mergers and the dynamics of the kiloparsecs-scale structure and beyond, in the local-galaxies in Schwarzschild-de Sitter (SDS) background, rather than in Schwarzschild or Newtonian paradigm. Owing to the complex and nonlinear character of the underlying magnetohydrodynamical equations in general relativistic (GR) regime, it is quite useful to have an Newtonian analogous potential containing all the important GR features that allows to treat the problem in Newtonian framework for study of accretion and its related processes. From the principle of conserved Hamiltonian of the test particle motion, here, a three dimensional Newtonian analogous potential has been obtained in spherical geometry corresponding to SDS/Schwarzschild anti-de Sitter (SADS) spacetime, that reproduces almost al...
Classification of Kerr-de Sitter-like spacetimes with conformally flat Scri
Mars, Marc; Senovilla, José M M
2016-01-01
We provide a classification of $\\Lambda>0$-vacuum spacetimes which admit a Killing vector field with respect to which the associated "Mars-Simon tensor" (MST) vanishes and having a conformally flat $\\mathcal{J}^-$ (or $\\mathcal{J}^+$). To that end, we also give a complete classification of conformal Killing vector fields on the $3$-sphere $\\mathbb{S}^3$ up to M\\"obius transformations shedding light on the two fundamental constants that characterize the family of Kerr-de Sitter-like spacetimes, which turn out to be well-defined geometrical invariants. The topology of $\\mathcal{J}$ is determined in every case, and a characterization result at $\\mathcal{J}$ of the Kerr-de Sitter family presented.
Design of attitude solution algorithm for tail-sitter VTOL UAV
Directory of Open Access Journals (Sweden)
Donghui LIU
2016-02-01
Full Text Available The tail-sitter Vertical Takeoff and Landing (VTOL Unmanned Aerial Vehicle(UAV, flying in a fixed-wing model, overcomes many shortcomings of traditional fixed-wing UAVs, and inherits the advantage of high overall efficiency, which means it has great development potential and very broad application prospects. The attitude of tail-sitter VTOL UAV shows a wide change range in its takeoff and landing stages, and when the attitude sensor changes more than 90 degrees in pitch direction, the Euler angles converted by the Quaternions will have singular points, which means gimbal deadlock appears. From the solution algorithm, this paper provides a method of changing the order of rotation to avoid the appearance of singular points. The results show that this method can be well applied to the attitude solution of the VTOL UAV.
Quasi-normal modes of Schwarzschild-de Sitter black holes
Zhidenko, A
2004-01-01
The low-laying frequencies of characteristic quasi-normal modes (QNM) of Schwarzschild-de Sitter (SdS) black holes have been calculated for fields of different spin using the 6th-order WKB approximation and the approximation by the P"{o}shl-Teller potential. The well-known asymptotic formula for large $l$ is generalized here on a case of the Schwarzchild-de Sitter black hole. In the limit of the near extreme $L$ term the results given by both methods are in a very good agreement, and in this limit fields of different spin decay with the same rate. In addition, the fact that the spectrum of massless Dirac quasi-normal frequencies is the same for opposite chyrality has been numerically proved for SdS background.
Restoration of the covariant gauge α in the initial field of gravity in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Cheong, Lee Yen; Yan, Chew Xiao [Department of Fundamental and Applied Sciences, Universiti Teknologi Petronas, Bandar Seri Iskandar, Tronoh 31750, Perak (Malaysia)
2014-03-05
The gravitational field generated by a mass term and the initial surface through covariant retarded Green's function for linearized gravity in de Sitter spacetime was studied recently [4, 5] with the covariant gauges set to β = 2/3 and α = 5/3. In this paper we extend the work to restore the gauge parameter α in the field coming from the initial data using the method of shifting the parameter. The α terms in the initial field cancels exactly with the one coming from the source term. Consequently, the correct field configuration, with two equal mass points moving in its geodesic, one located at the North pole and another one located at the South pole, is reproduced in the whole manifold of de Sitter spacetime.
Isometry generators in momentum representation of the Dirac theory on the de Sitter spacetime
Cotăescu, Ion I.; Băltăţeanu, Doru-Marcel
2015-11-01
In this paper, it is shown that the covariant representation (CR) transforming the Dirac field under de Sitter isometries is equivalent to a direct sum of two unitary irreducible representations (UIRs) of the Sp(2, 2) group transforming alike the particle and antiparticle field operators in momentum representation. Their basis generators and Casimir operators are written down for the first time finding that these representations are equivalent to an UIR from the principal series whose canonical labels are determined by the fermion mass and spin. The properties of the conserved observables (i.e. one-particle operators) associated to the de Sitter isometries via Noether theorem and of the corresponding Pauli-Lubanski type operator are also pointed out.
Tachyon fields with effects of quantum matter in an Anti-de Sitter Universe
Elizalde, E; Elizalde, Emilio; Hurtado, John Quiroga
2004-01-01
We consider an Anti-de Sitter universe filled by quantum conformal matter with the contribution from the usual tachyon and a perfect fluid. The model represents the combination of a trace-anomaly annihilated and a tachyon driven Anti-de Sitter universe. The influence exerted by the quantum effects and by the tachyon on the AdS space is studied. The radius corresponding to this universe is calculated and the effect of the tachyon potential is discussed, in particular, concerning to the possibility to get an accelerated scale factor for the proposed model (implying an accelerated expansion of the AdS type of universe). Fulfillment of the cosmological energy conditions in the model is also investigated
Quantum fields from global propagators on asymptotically Minkowski and extended de Sitter spacetimes
Vasy, András
2015-01-01
We consider the wave equation on asymptotically Minkowski spacetimes and the Klein-Gordon equation on even asymptotically de Sitter spaces. In both cases we show that the extreme difference of propagators (i.e. retarded propagator minus advanced, or Feynman minus anti-Feynman), defined as Fredholm inverses, induces a symplectic form on the space of solutions with wave front set confined to the radial sets. Furthermore, we construct isomorphisms between the solution spaces and symplectic spaces of asymptotic data. As an application of this result we obtain distinguished Hadamard two-point functions from asymptotic data. Ultimately, we prove that the corresponding Quantum Field Theory on asymptotically de Sitter spacetimes induces canonically a QFT beyond the future and past conformal horizon, i.e. on two even asymptotically hyperbolic spaces. Specifically, we show this to be true both at the level of symplectic spaces of solutions and at the level of Hadamard two-point functions.
Halstead, Evan
2011-01-01
We investigate the time evolution of the temperature and entropy of a gravitationally collapsing de Sitter Schwarzschild domain wall as seen by an asymptotic observer. Recent work has completed this analysis for Schwarzschild and 3+1 BTZ domain walls. There were some striking qualitative differences between the two. Specifically, the BTZ domain wall exhibited a decrease in entropy over time. However, it contained both a cosmological constant and a different topology from the Schwarzschild domain wall, and we wish to isolate which of these is responsible for the qualitative differences. Hence, we will study the de Sitter Schwarzschild domain wall, as it has identical topology to the Schwarzschild domain wall yet also contains a cosmological constant. We utilize a wavefunctional approach where we couple a scalar field to the background of the collapsing domain wall and determine the spectrum of the radiation as a function of time. The fact that the distribution is thermal allows for the determination of the tem...
Asymptotics with a positive cosmological constant: II. Linear fields on de Sitter space-time
Ashtekar, Abhay; Kesavan, Aruna
2015-01-01
Linearized gravitational waves in de Sitter space-time are analyzed in detail to obtain guidance for constructing the theory of gravitational radiation in presence of a positive cosmological constant in full, nonlinear general relativity. Specifically: i) In the exact theory, the intrinsic geometry of $\\scri$ is often assumed to be conformally flat in order to reduce the asymptotic symmetry group from $\\Diff$ to the de Sitter group. Our {results show explicitly} that this condition is physically unreasonable; ii) We obtain expressions of energy-momentum and angular momentum fluxes carried by gravitational waves in terms of fields defined at $\\scrip$; iii) We argue that, although energy of linearized gravitational waves can be arbitrarily negative in general, gravitational waves emitted by physically reasonable sources carry positive energy; and, finally iv) We demonstrate that the flux formulas reduce to the familiar ones in Minkowski space-time in spite of the fact that the limit $\\Lambda \\to 0$ is discontin...
Hawking radiation of Reissner-Nordstrom-de Sitter black hole by Hamilton-Jacobi method
Hossain, M Ilias
2013-01-01
In Refs. (M. Atiqur Rahman, M. Ilias Hossain (2012) Phys. Lett. B {\\bf 712} 1), we have developed Hamilton-Jacobi method for dynamical spacetime and discussed Hawking radiation of Schwarzschild-de Sitter black hole by massive particle tunneling method. In this letter, we have investigated the hawking purely thermal and nonthermal radiations of Reissner-Nordstr\\"{o}m-de Sitter (RNdS) black hole. We have considered energy and angular momentum as conserved and shown that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum. The results we have obtained for RNdS black hole is also in accordance with Parikh and Wilczek\\rq s opinion and recovered the new result for Hawking radiation of RNdS black hole.
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.
Microlocal analysis of asymptotically hyperbolic and Kerr-de Sitter spaces
Vasy, Andras
2010-01-01
In this paper we develop a general, systematic, microlocal framework for the Fredholm analysis of non-elliptic problems, including high energy (or semiclassical) estimates, which is stable under perturbations. This framework is relatively simple given modern microlocal analysis, and only takes a bit over a dozen pages after the statement of notation. It resides on a compact manifold without boundary, hence in the standard setting of microlocal analysis, including semiclassical analysis. The rest of the paper is devoted to applications. Many natural applications arise in the setting of non-Riemannian b-metrics in the context of Melrose's b-structures. These include asymptotically Minkowski metrics, asymptotically de Sitter-type metrics on a blow-up of the natural compactification and Kerr-de Sitter-type metrics. The simplest application, however, is to provide a new approach to analysis on Riemannian or Lorentzian (or indeed, possibly of other signature) conformally compact spaces (such as asymptotically hyper...
Rain, Hail, and Drip frames of the Schwarzschild-de Sitter Geometry
Finch, Tehani
2017-01-01
Various families of coordinate systems associated with observers moving inwardly along radial geodesics in the Schwarzschild geometry have been constructed by generalizing the Painleve-Gullstrand coordinates. Such observers have categorized as being in the rain frame, a hail frame, or a drip frame, by Taylor and Wheeler. This framework naturally progresses into a search for counterparts of these coordinate systems for the Schwarzschild-de Sitter (SdS) geometry. Consideration of local measurements made by a fiducial observer suggests that the conserved Killing quantity which best fits the designation of ``energy'' in the SdS geometry differs from the one which is typically denoted as such. This leads to Painleve-Gullstrand-style coordinate systems for the SdS geometry that differ from the naïve extrapolations of the Schwarzschild or de Sitter geometries.
Charged Rotating AdS Black Hole and Its Thermodynamics in Conformal Gravity
Liu, Hai-Shan
2013-01-01
We obtain the charged rotating black hole in conformal gravity. The metric is asymptotic to the (anti-)de Sitter spacetime. The contribution to the metric from the charges has a slower falloff than that in the Kerr-Newman AdS black hole. We analyse the global structure and obtain all the thermodynamical quantities including the mass, angular momentum, electric/magnetic charges and their thermodynamical conjugates. We verify that the first law of thermodynamics holds. We also obtain the new neutral rotating black holes that are beyond Einstein metrics. In contrast to the static ones, these rotating black holes have no parameters associated with the massive spin-2 hair.
Schwinger Effect in (A)dS and Charged Black Hole
Kim, Sang Pyo
2015-01-01
In an (Anti-) de Sitter space and a charged black hole the Schwinger effect is either enhanced by the Hawking radiation or suppressed by the negative curvature. We use the contour integral method to calculate the production of charged pairs in the global (A)dS space. The charge emission from near-extremal black hole is found from the AdS geometry near the horizon and interpreted as the Schwinger effect in a Rindler space with the surface gravity for the acceleration as well as the Schwinger effect in AdS space.
Point splitting renormalization of Schwinger induced current in de Sitter spacetime
Hayashinaka, Takahiro
2016-01-01
The covariant and gauge invariant calculation of the current expectation value in the homogeneous electric field in 1+3 dimensional de Sitter spacetime is shown. The result accords with previous work obtained by using adiabatic subtraction scheme. We therefore conclude the counterintuitive behaviors of the current in the infrared (IR) regime such as IR hyperconductivity and negative current are not artifacts of the renormalization scheme, but are real IR effects of the spacetime.
Discrete Torsion, (Anti) de Sitter D{sub 4}-Brane and Tunneling
Energy Technology Data Exchange (ETDEWEB)
Singh, Abhishek K.; Pandey, P.K.; Singh, Sunita; Kar, Supriya, E-mail: skkar@physics.du.ac.in
2014-06-15
We obtain quantum geometries on a vacuum created pair of a (DD{sup ¯}){sub 3}-brane, at a Big Bang singularity, by a local two form on a D{sub 4}-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 (DD{sup ¯})-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 D{sub 4}-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.
Thermodynamics of Regular Cosmological Black Holes with the de Sitter Interior
Directory of Open Access Journals (Sweden)
Irina Dymnikova
2011-11-01
Full Text Available We address the question of thermodynamics of regular cosmological spherically symmetric black holes with the de Sitter center. Space-time is asymptotically de Sitter as r → 0 and as r → ∞. A source term in the Einstein equations connects smoothly two de Sitter vacua with different values of cosmological constant: 8πGTμν = Λδμν as r → 0, 8πGTμν = λδμν as r → ∞ with λ < Λ. It represents an anisotropic vacuum dark fluid defined by symmetry of its stress-energy tensor which is invariant under the radial boosts. In the range of the mass parameter Mcr1 ≤ M ≤ Mcr2 it describes a regular cosmological black hole. Space-time in this case has three horizons: a cosmological horizon rc, a black hole horizon rb < rc, and an internal horizon ra < rb, which is the cosmological horizon for an observer in the internal R-region asymptotically de Sitter as r → 0. We present the basicfeatures of space-time geometry and the detailed analysis of thermodynamics of horizons using the Padmanabhan approach relevant for a multi-horizon space-time with a non-zero pressure. We find that in a certain range of parameters M and q =√Λ/λ there exist a global temperature for an observer in the R-region between the black hole horizon rb and cosmological horizon rc. We show that a second-order phase transition occurs in the course of evaporation, where a specific heat is broken and a temperature achieves its maximal value. Thermodynamical preference for a final point of evaporation is thermodynamically stable double-horizon (ra = rb remnant with the positive specific heat and zero temperature.
Cosmic Censorship of Rotating Anti-de Sitter Black Hole with a Probe
Gwak, Bogeun
2015-01-01
We test the validity of cosmic censorship in the rotating anti-de Sitter black hole through a particle absorption. For this purpose, we investigate whether the extremal black hole can be overspun by a particle. We construct the particle equations of motions to satisfy the laws of thermodynamics. With the particle absorption, 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.
From the Complete Yang Model to Snyder's Model, de Sitter Special Relativity and Their Duality
Wu, Hong-Tu; Guo, Han-Ying
2008-01-01
By means of Dirac procedure, we re-examine Yang's quantized space-time model, its relation to Snyder's model, the de Sitter special relativity and their UV-IR duality. Starting from a dimensionless dS_5-space in a 5+1-d Mink-space a complete Yang model at both classical and quantum level can be presented and there really exist Snyder's model, the dS special relativity and the duality.
Entropy in the NUT-Kerr-Newman Black Holes in the Background of de Sitter Spacetime
Institute of Scientific and Technical Information of China (English)
葛先辉; 沈有根
2002-01-01
We calculate the entropy of the fermion field in the NUT-Kerr-Newman black holes in the background of the de Sitter spacetime by using the improved brick-wall method and the membrane model. Here the Euler characteristic of the black holes is over two. The results show that, as the cut-off is properly chosen, the entropy in the black hole satisfies the Bekenstein-Hawking area law.
The geometry of canal surfaces and the length of curves in de Sitter space
Langevin, Rémi
2011-01-01
We find the minimal value of the length in de Sitter space of closed space-like curves with non-vanishing non-space-like geodesic curvature vector. These curves are in correspondence with closed almost-regular canal surfaces, and their length is a natural magnitude in conformal geometry. As an application, we get a lower bound for the total conformal torsion of closed space curves.
Institute of Scientific and Technical Information of China (English)
HAN Yi-Wen; YANG Shu-Zheng
2005-01-01
@@ We extend Parikh's recent work to Schwarzchild-anti-de Sitter black hole with topological defect whose ArnowittDeser-Misner (ADM) mass is no longer identical to its mass parameter. We view the Hawking radiation as a tunnelling process across the event horizon and the cosmological horizon. From the tunnelling probability, we find a leading correction to the semi-classical emission rate. The result employs an underlying unitary theory.
Institute of Scientific and Technical Information of China (English)
HAN Yi-Wen; YANG Shu-Zheng
2007-01-01
We extend Zhang and Zhao's recent work to the Schwarzschild-anti-de Sitter black hole with topological defect, whose Arnowitt-Deser-Misner (ADM) mass is no longer identical to its mass parameter. The behavior of the tunneling massive particle is investigated and the emission rate is calculated. The result satisfies an underlying unitary theory and takes the same functional form as that of the mass-less particle.
Dispersion relations and entropy of scalar fields in Rindler and de Sitter spaces
Lenz, F; Yazaki, K
2014-01-01
Properties of scalar fields in Rindler and de Sitter spaces are the subject of this work. Using the "brick wall model'' the dispersion relations are determined and the remarkable properties common to both spaces as well as their differences are discussed. Equipped with these tools the horizon induced thermodynamics is revisited and shown to be dominated by a single mode propagating perpendicular to the horizon. Explicit expressions for the partition function, entropy and heat capacity for massless and massive fields are presented.
On the covariant gauge {alpha} of the linearized gravity in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Cheong, Lee Yen [Department of Fundamental and Applied Science Universiti Teknologi Petronas, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)
2012-09-26
In previous work, we studied the linearized gravity with covariant gauge {beta}= 2/3 and {alpha}= 5/3. It was found that the sum of the source and initial contributions reproduces the correct field configuration over the whole de Sitter spacetime. In this paper, we extend this work to generalizing the linearized gravitational field in an arbitrary value of the gauge parameter {alpha} but the gauge parameter {beta} remains the same.
Hawking radiation from the dilaton-(anti) de Sitter black hole via covariant anomaly
Institute of Scientific and Technical Information of China (English)
Han Yi-Wen; Bao Zhi-Qing; Hong Yun
2009-01-01
Adopting the anomaly cancellation method, initiated by Robinson and Wilczek recently, this paper discusses Hawking radiation from the dilaton-(anti) de Sitter black hole. To save the underlying gauge and general covariance, it introduces covariant fluxes of gauge and energy-momentum tensor to cancel the gauge and gravitational anomalies. The result shows that the introduced compensating fluxes are equivalent to those of a 2-dimensional blackbody radiation at Hawking temperature with appropriate chemical potential.
Free massless fermionic fields of arbitrary spin in d-dimensional anti-de Sitter space
Energy Technology Data Exchange (ETDEWEB)
Vasiliev, M.A.
1988-04-25
Free massless fermionic fields of arbitrary spins, corresponding to fully symmetric tensor-spinor irreducible representations of the flat little group SO(d-2), are described in d-dimensional anti-de Sitter space in terms of differential forms. Appropriate linearized higher-spin curvature 2-forms are found. Explicitly gauge invariant higher-spin actions are constructed in terms of these linearized curvatures.
Entropy and topology of the Kerr-de Sitter black hole
Institute of Scientific and Technical Information of China (English)
陈松柏; 荆继良
2002-01-01
By using the path integral method of Gibbons and Hawking, the entropy of the Kerr-de Sitter black hole isinvestigated under the microcanonical ensemble. We find that the entropy is one eighth the sum of the products of theEuler number of its cosmological horizon and event horizon with their respective areas. It is shown that the origin ofthe entropy of the black hole is related to the topology of its instanton.
Conservation laws for classical particles in anti-de Sitter-Beltrami space
Angsachon, T.; Manida, S. N.; Tchaikovskii, M. E.
2013-07-01
The behavior of free classical pointlike particles is governed by conservation laws in the anti-de Sitter space. We present the general form of these laws and their realization in the Beltrami coordinates. In these coordinates, we can pass to the nonrelativistic limit resulting in physics in the R space. We construct the initial covariant distribution function for an ideal gas uniformly filling the entire R space.
All gaugings and stable de Sitter in D=7 half-maximal supergravity
Energy Technology Data Exchange (ETDEWEB)
Dibitetto, Giuseppe [Institutionen för fysik och astronomi, University of Uppsala, Box 803, SE-751 08 Uppsala (Sweden); Fernández-Melgarejo, Jose J. [Jefferson Physical Laboratory, Harvard University, Cambridge, MA 02138 (United States); Marqués, Diego [Instituto de Astronomía y Física del Espacio (CONICET-UBA) C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina)
2015-11-05
We study the general formulation of gauged supergravity in seven dimensions with sixteen supercharges keeping duality covariance by means of the embedding tensor formalism. We first classify all inequivalent duality orbits of consistent deformations. Secondly, we analyse the complete set of critical points in a systematic way. Interestingly, we find the first examples of stable de Sitter solutions within a theory with such a large amount of supersymmetry.
Superluminal Neutrinos from Special Relativity with de Sitter Space-time Symmetry
Yan, Mu-Lin; Xiao, Neng-Chao; Huang, Wei; Hu, Sen
2011-01-01
We explore the recent OPERA experiment of superluminal neutrinos in the framework of Special Relativity with de Sitter space-time 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 $c_{photon}$ and the phase velocity of a light wave in vacuum $c_{wave}=\\lambda\
Weyl geometry, anti-De Sitter space, and $\\Phi^4$-theory
Camargo, H A; Socolovsky, M
2015-01-01
We study the Gaussian approximation to the quantum fluctuations of the metric of the four dimensional anti-De Sitter spacetime. The associated massless scalar field has a quartic self interaction, for which we construct the generating functional of the $n$-point correlation functions. The concomitant infrared divergence is cured by a mass renormalization provided by the cosmological constant, which is also responsible for the renormalization of the coupling constant of the field theory.
Holographic principle versus Bohr's principle: eternal Schwarzschild-anti-de Sitter geometry
Emelyanov, Slava
2015-01-01
It is shown that Bohr's correspondence principle and the holographic principle are incompatible in the background of an eternal Schwarzschild-anti-de Sitter geometry. The argument is based on the observation that algebraic structures of local quantum field and CFT operators are not equivalent. A CFT Hilbert space representation is elaborated which may correspond to the AdS black hole in the dual theory.
Quantum dynamic of massive particle On 1+3 De Sitter space-time
Directory of Open Access Journals (Sweden)
A Rabeie
2012-09-01
Full Text Available The phase space which is related to the motion of massive particle on 1+3- De sitter space is a 3-dimensional complex sphere. Our main aim in this study is discribing this movement in the frame quantum mechanics. Transfering from classical mechanic to quantum mechanics is possible by means of coherent states. Thus, after determination of this state, we quantize some of the classical observables.
Quantum dynamic of massive particle On 1+3 De Sitter space-time
2012-01-01
The phase space which is related to the motion of massive particle on 1+3- De sitter space is a 3-dimensional complex sphere. Our main aim in this study is discribing this movement in the frame quantum mechanics. Transfering from classical mechanic to quantum mechanics is possible by means of coherent states. Thus, after determination of this state, we quantize some of the classical observables.
Automodelling solutions of the Higgs-field nonlinear wave equation in the de Sitter space.
Dyshko, A. L.; Konyukhova, N. B.; Voronov, N. A.
2000-04-01
The effect of the expansion of the Universe on such classical physical objects as spherical bubbles is studied. The authors look for automodelling solutions to scalar Higgs-field equation in the de Sitter space and compare them with the bubble type solutions in the thin-wall approximation. The automodelling bubbles could be considered as critical or singular ones because they collapse in an infinite time. Multinodal solutions as enclosed bubbles are discovered numerically.
Warped anti-de Sitter in 3d (2,0) Supergravity
Moutsopoulos, George
2016-01-01
We comment on the ubiquity of the so-called warped anti-de Sitter spacetimes in three-dimensional (2,0) supergravity theory. By using isometry-invariant tensors and simple counting, we prove their existence for arbitrary $(2,0)$ supergravity models suitably defined close to a minimal model. We also analyze their offshell supersymmetry and the supersymmetry of two geometric orbifolds.
Anti-de Sitter quantum field theory and the AdS-CFT correspondence
Moschella, U.
We give a short account of a new approach to anti-de Sitter quantum field theory that is based on the assumption of certain analyticity properties of the n-point correlation functions. We then discuss the application of this formalism to the construction of conformal field theories that are naturally obtained on the covering of the cone asymptotic to the AdS manifold, and that satisfy the axioms of Luscher and Mack.
Point splitting renormalization of Schwinger induced current in de Sitter spacetime
Energy Technology Data Exchange (ETDEWEB)
Hayashinaka, Takahiro [Research Center for the Early Universe (RESCEU), Graduate School of Science,The University of Tokyo, Bunkyo, Tokyo, 113-0033 (Japan); Department of Physics, Graduate School of Science,The University of Tokyo, Bunkyo, Tokyo, 113-0033 (Japan); Yokoyama, Jun’ichi [Research Center for the Early Universe (RESCEU), Graduate School of Science,The University of Tokyo, Bunkyo, Tokyo, 113-0033 (Japan); Department of Physics, Graduate School of Science,The University of Tokyo, Bunkyo, Tokyo, 113-0033 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU),WPI, UTIAS, The University of Tokyo, Kashiwa, Chiba, 277-8583 (Japan)
2016-07-08
The covariant and gauge invariant calculation of the current expectation value in the homogeneous electric field in 1+3 dimensional de Sitter spacetime is shown. The result accords with previous work obtained by using adiabatic subtraction scheme. We therefore conclude the counterintuitive behaviors of the current in the infrared (IR) regime such as IR hyperconductivity and negative current are not artifacts of the renormalization scheme, but are real IR effects of the spacetime.
Gravitationally induced adiabatic particle productions: From Big Bang to de Sitter
de Haro, Jaume
2015-01-01
In the background of a flat homogeneous and isotropic space-time, we consider a scenario of the universe driven by the gravitationally induced constant `adiabatic' particle productions. We have shown that this universe attains a big bang singularity in the past and at late-time, it asymptotically becomes de Sitter. To clarify this model universe, we perform a dynamical analysis. Further, we discussed the possible effects of this particle creations in the context of loop quantum cosmology.
PURE STATE ENTANGLEMENT ENTROPY IN NONCOMMUTATIVE 2D DE SITTER SPACE TIME
Directory of Open Access Journals (Sweden)
M.F Ghiti
2014-12-01
Full Text Available Using the general modified field equation, a general noncommutative Klein-Gordon equation up to the second order of the noncommutativity parameter is derived in the context of noncommutative 2D De Sitter space-time. Using Bogoliubov coefficients and a special technics called conformal time; the boson-antiboson pair creation density is determined. The Von Neumann boson-antiboson pair creation quantum entanglement entropy is presented to compute the entanglement between the modes created presented.
On Minkowski-like and de Sitter-like space-times
Lübbe, Christian
2010-05-01
This article summarises joint work with Juan A. Valiente-Kroon on de Minkowski-like and de Sitter-like space-times and was presented by the author at ERE 2009 in Bilbao. The existence and stability problem is re-examined using extended conformal field equations. In particular we make use of a gauge based on conformal geodesics to obtain a priori the location of the conformal boundary from the initial data.
Spinning particles in the Perturbed Schwarzschild-de Sitter Space-Time
Naboulsi, R
2003-01-01
I study spinning particles in Schwarschild-de Sitter (SdS) space-time where the cosmological constant is replaced by an effective one inspired from [1,2]. Equations of motions are investigated. It is shown that the equilibrium conditions are independant of the spin of the test particles and are satisfied only when the cosmological constant Lambda > 3m^2 where m is a constant having the dimension of time^{-1}.
A preferred ground state for the scalar field in de Sitter space
Aslanbeigi, Siavash
2013-01-01
We investigate a recent proposal for a distinguished vacuum state of a free scalar quantum field in an arbitrarily curved spacetime, known as the Sorkin-Johnston (SJ) vacuum, by applying it to de Sitter space. We derive the associated two-point functions on both the global and Poincar\\'e (cosmological) patches in general d+1 dimensions. In all cases where it is defined, the SJ vacuum belongs to the family of de Sitter invariant alpha-vacua. We obtain different states depending on the spacetime dimension, mass of the scalar field, and whether the state is evaluated on the global or Poincar\\'e patch. We find that the SJ vacuum agrees with the Euclidean/Bunch-Davies state for heavy ("principal series") fields on the global patch in even spacetime dimensions. We also compute the SJ vacuum on a causal set corresponding to a causal diamond in 1+1 dimensional de Sitter space. Our simulations show that the mean of the SJ two-point function on the causal set agrees well with its expected continuum counterpart.
A preferred ground state for the scalar field in de Sitter space
Aslanbeigi, S.; Buck, M.
2013-08-01
We investigate a recent proposal for a distinguished vacuum state of a free scalar quantum field in an arbitrarily curved spacetime, known as the Sorkin-Johnston (SJ) vacuum, by applying it to de Sitter space. We derive the associated two-point functions on both the global and Poincaré (cosmological) patches in general d + 1 dimensions. In all cases where it is defined, the SJ vacuum belongs to the family of de Sitter invariant α-vacua. We obtain different states depending on the spacetime dimension, mass of the scalar field, and whether the state is evaluated on the global or Poincaré patch. We find that the SJ vacuum agrees with the Euclidean/Bunch-Davies state for heavy ("principal series") fields on the global patch in even spacetime dimensions. We also compute the SJ vacuum on a causal set corresponding to a causal diamond in 1 + 1 dimensional de Sitter space. Our simulations show that the mean of the SJ two-point function on the causal set agrees well with its expected continuum counterpart.
Inflation including collapse of the wave function: the quasi-de Sitter case
Energy Technology Data Exchange (ETDEWEB)
Leon, Gabriel [Universidad de Buenos Aires, Ciudad Universitaria-PabI, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Landau, Susana J. [Universidad de Buenos Aires y IFIBA, CONICET, Ciudad Universitaria-PabI, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Piccirilli, Maria Pia [Universidad Nacional de La Plata, Grupo de Astrofisica, Relatividad y Cosmologia, Facultad de Ciencias Astronomicas y Geofisicas, Pcia de Buenos Aires (Argentina)
2015-08-15
The precise physical mechanism describing the emergence of the seeds of cosmic structure from a perfect isotropic and homogeneous universe has not been fully explained by the standard version of inflationary models. To handle this shortcoming, D. Sudarsky and collaborators have developed a proposal: the self-induced collapse hypothesis. In this scheme, the objective collapse of the inflaton wave function is responsible for the emergence of inhomogeneity and anisotropy at all scales. In previous papers, the proposal was developed with an almost exact de Sitter space-time approximation for the background that led to a perfect scale-invariant power spectrum. In the present article, we consider a full quasi-de Sitter expansion and calculate the primordial power spectrum for three different choices of the self-induced collapse. The consideration of a quasi-de Sitter background allows us to distinguish departures from an exact scale-invariant power spectrum that are due to the inclusion of the collapse hypothesis. These deviations are also different from the prediction of standard inflationary models with a running spectral index. A comparison with the primordial power spectrum and the CMB temperature fluctuation spectrum preferred by the latest observational data is also discussed. From the analysis performed in this work, it follows that most of the collapse schemes analyzed in this paper are viable candidates to explain the present observations of the CMB fluctuation spectrum. (orig.)
Recursive Techniques for Computing Gluon Scattering in Anti-de-Sitter Space
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.
Axial and polar gravitational wave equations in a de Sitter expanding universe by Laplace transform
Viaggiu, Stefano
2017-02-01
In this paper we study the propagation in a de Sitter universe of gravitational waves generated by perturbating some unspecified spherical astrophysical object in the frequencies domain. We obtain the axial and polar perturbation equations in a cosmological de Sitter universe in the usual comoving coordinates, the coordinates we occupy in our galaxy. We write down the relevant equations in terms of Laplace transform with respect to the comoving time t instead of the usual Fourier one that is no longer available in a cosmological context. Both axial and polar perturbation equations are expressed in terms of a non trivial mixture of retarded-advanced metric coefficients with respect to the Laplace parameter s (complex translation). The axial case is studied in more detail. In particular, the axial perturbations can be reduced to a master linear second-order differential equation in terms of the Regge–Wheeler function Z where a coupling with a retarded Z with respect to the cosmological time t is present. It is shown that a de Sitter expanding universe can change the frequency ω of a gravitational wave as perceived by a comoving observer. The polar equations are much more involved. Nevertheless, we show that the polar perturbations can also be expressed in terms of four independent integrable differential equations.
Instability of de Sitter brane and horizon entropy in 6D braneworld
Kinoshita, Shunichiro; Mukohyama, Shinji
2007-01-01
We investigate thermodynamic and dynamical stability of a family of six-dimensional braneworld solutions with de Sitter branes. First, we investigate thermodynamic stability in terms of de Sitter entropy. We see that the family of solutions is divided into two distinct branches: the high-entropy branch and the low-entropy branch. By analogy with ordinary thermodynamics, it is expected that the high-entropy branch be stable and the low-entropy branch be unstable. Next, we investigate dynamical stability by analyzing linear perturbations around the solutions. Perturbations are decomposed into scalar-, vector- and tensor-sectors according to the representation of the 4D de Sitter symmetry, and each sector is analyzed separately. It is found that when the Hubble expansion rates on the branes are too large, there appears a tachyonic mode in the scalar sector and the background solution becomes dynamically unstable. We analytically show that the onset of the thermodynamic instability and that of the dynamical insta...
Evidence for special relativity with de Sitter space-time symmetry
Institute of Scientific and Technical Information of China (English)
YAN Mu-Lin
2011-01-01
I show the formulation of de Sitter Special Relativity (dS-SR) based on Dirac-Lu-Zou-Guo's discussions, dS-SR quantum mechanics is formulated, and the dS-SR Dirac equation for hydrogen is suggested. The equation in the earth-QSO framework reference is solved by means of the adiabatic approach. It's found that the fine-structure "constant" α in dS-SR varies with time. By means of the t-z relation of the ACDM model, α's time-dependency becomes redshift z-dependent. The dS-SR's predictions of △α/α agree with data of spectra of 143 quasar absorption systems, the dS-space-time symmetry is SO(3,2) (i.e., anti-dS group) and the universal parameter R (de Sitter ratio) in dS-SR is estimated to be R ≈ 2.73 x 10 ly. The effects of dS-SR become visible at the cosmic space-time scale (i.e., the distance≥ 10 ly). At that scale, dS-SR is more reliable than Einstein SR. The α-variation with time is evidence of SR with de Sitter symmetry.
High Energy Physics Signatures from Inflation and Conformal Symmetry of de Sitter
Kehagias, Alex
2015-01-01
During inflation, the geometry of spacetime is described by a (quasi-)de Sitter phase. Inflationary observables are determined by the underlying (softly broken) de Sitter isometry group SO(1, 4) which acts like a conformal group on R^3: when the fluctuations are on super-Hubble scales, the correlators of the scalar fields are constrained by conformal invariance. Heavy fields with mass m larger than the Hubble rate H correspond to operators with imaginary dimensions in the dual Euclidean three-dimensional conformal field theory. By making use of the dS/CFT correspondence we show that, besides the Boltzmann suppression expected from the thermal properties of de Sitter space, the generic effect of heavy fields in the inflationary correlators of the light fields is to introduce power-law suppressed corrections of the form O(H^2/m^2). This can be seen, for instance, at the level of the four-point correlator for which we provide the correction due to a massive scalar field exchange.
Inflation including collapse of the wave function: The quasi-de Sitter case
León, Gabriel; Piccirilli, María Pía
2015-01-01
The emergence of the seeds of cosmic structure from a perfect isotropic and homogeneous Universe has not been fully explained by the standard version of inflationary models. To handle this shortcoming, D. Sudarsky and collaborators have developed a proposal: "the self-induced collapse hypothesis." In this scheme, the collapse of the inflaton wave function is responsible for the emergence of inhomogeneity and anisotropy at each scale. In previous papers, the proposal was developed with an almost exact de Sitter space-time approximation for the background that lead to a perfect scale-invariant power spectrum. In this paper, we consider a quasi-de Sitter expansion factor and calculate the primordial power spectrum for three different choices of the self-induced collapse. The consideration of a quasi-de Sitter background allow us to distinguish departures from an exact scale-invariant power spectrum that are due to the inclusion of the collapse hypothesis. These deviations are also different from the prediction o...
Detecting the Curvature of de Sitter Universe with Two Entangled Atoms
Tian, Zehua; Wang, Jieci; Jing, Jiliang; Dragan, Andrzej
2016-01-01
Casimir-Polder interaction arises from the vacuum fluctuations of quantum field that depend on spacetime curvature and thus is spacetime-dependent. Here we show how to use the resonance Casimir-Polder interaction (RCPI) between two entangled atoms to detect spacetime curvature. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature relevant to the temperature felt by the static observer. It is characterized by a 1/L2 power law decay when beyond a characteristic length scale associated to the breakdown of a local inertial description of the two-atom system. However, the RCPI of the same setup embedded in a thermal bath in the Minkowski universe is temperature-independent and is always characterized by a 1/L power law decay. Therefore, although a single static atom in the de Sitter-invariant vacuum responds as if it were bathed in thermal radiation in a Minkowski universe, using the distinct difference between RCPI of two entangled atoms one can in principle distinguish these two universes. PMID:27731419
Thermodynamics of horizons: de Sitter black holes and reentrant phase transitions
Kubizňák, David; Simovic, Fil
2016-12-01
In this paper we propose a straightforward method for understanding the thermodynamics of black holes in de Sitter space, one that will allow us to study these black holes in a way that is analogous to the anti-de Sitter case. As per usual, we formulate separate thermodynamic first laws for each horizon present in the spacetime, and study their thermodynamics as if they were independent systems characterized by their own temperature. That these systems are not entirely independent and various thermodynamic quantities in them are in fact ‘correlated’ is reflected by the fact that their thermodynamics can be captured by a single Gibbs free energy-like thermodynamic potential. This quantity contains information about possible phase transitions in the system and allows us to uncover a rich phase structure for de Sitter black holes. In particular, we discover reentrant phase transitions for Kerr-dS black holes in six dimensions, a phenomenon recently observed for their six dimensional AdS cousins.
Detecting the Curvature of de Sitter Universe with Two Entangled Atoms.
Tian, Zehua; Wang, Jieci; Jing, Jiliang; Dragan, Andrzej
2016-10-12
Casimir-Polder interaction arises from the vacuum fluctuations of quantum field that depend on spacetime curvature and thus is spacetime-dependent. Here we show how to use the resonance Casimir-Polder interaction (RCPI) between two entangled atoms to detect spacetime curvature. We find that the RCPI of two static entangled atoms in the de Sitter-invariant vacuum depends on the de Sitter spacetime curvature relevant to the temperature felt by the static observer. It is characterized by a 1/L(2) power law decay when beyond a characteristic length scale associated to the breakdown of a local inertial description of the two-atom system. However, the RCPI of the same setup embedded in a thermal bath in the Minkowski universe is temperature-independent and is always characterized by a 1/L power law decay. Therefore, although a single static atom in the de Sitter-invariant vacuum responds as if it were bathed in thermal radiation in a Minkowski universe, using the distinct difference between RCPI of two entangled atoms one can in principle distinguish these two universes.
Universal area product formulas for rotating and charged black holes in four and higher dimensions.
Cvetič, M; Gibbons, G W; Pope, C N
2011-03-25
We present explicit results for the product of all horizon areas for general rotating multicharge black holes, both in asymptotically flat and asymptotically anti-de Sitter spacetimes in four and higher dimensions. The expressions are universal, and depend only on the quantized charges, quantized angular momenta and the cosmological constant. If the latter is also quantized these universal results may provide a "looking glass" for probing the microscopics of general black holes.
Action growth of charged black holes with a single horizon
Cai, Rong-Gen; Sasaki, Misao; Wang, Shao-Jiang
2017-06-01
According to the conjecture "complexity equals action," the complexity of a holographic state is equal to the action of a Wheeler-DeWitt (WDW) patch of black holes in anti-de Sitter space. In this paper we calculate the action growth of charged black holes with a single horizon, paying attention to the contribution from a spacelike singularity inside the horizon. We consider two kinds of such charged black holes: one is a charged dilaton black hole, and the other is a Born-Infeld black hole with β2Q2contributions from the bulk integral and the spacelike singularity are individually divergent, these two divergences just cancel each other and a finite action growth is obtained. But in this case, the Lloyd bound is violated as expected.
Chu, Yi-Zen
2013-01-01
We show how, for certain classes of curved spacetimes, one might obtain its retarded or advanced minimally coupled massless scalar Green's function by using the corresponding Green's functions in the higher dimensional Minkowski spacetime where it is embedded. Analogous statements hold for certain classes of curved Riemannian spaces, with positive definite metrics, which may be embedded in higher dimensional Euclidean spaces. The general formula is applied to (d >= 2)-dimensional de Sitter spacetime, and the scalar Green's function is demonstrated to be sourced by a line emanating infinitesimally close to the origin of the ambient (d+1)-dimensional Minkowski spacetime and piercing orthogonally through the de Sitter hyperboloids of all finite sizes. This method does not require solving the de Sitter wave equation directly. Only the zero mode solution to an ordinary differential equation, the "wave equation" perpendicular to the hyperboloid -- followed by a one dimensional integral -- needs to be evaluated. A t...
On Fayet-Iliopoulos Terms and de Sitter Vacua in Supergravity: Some Easy Pieces
Energy Technology Data Exchange (ETDEWEB)
Catino, Francesca; /Padua U. /INFN, Padua; Villadoro, Giovanni; /SLAC; Zwirner, Fabio; /Padua U. /INFN, Padua
2012-03-27
We clarify a number of issues on Fayet-Iliopoulos (FI) terms in supergravity, keeping the formalism at a minimum and making use of explicit examples. We explain why, if the U(1) vector is massive everywhere in field space, FI terms are not genuine and can always be redefined away or introduced when they are not present. We formulate a simple anomaly-free model with a genuine FI term, a classically stable de Sitter (dS) vacuum and no global symmetries. We explore the relation between N = 2 and N = 1 FI terms by discussing N = 1 truncations of N = 2 models with classically stable dS vacua.
Quantum de Sitter Spacetime and Energy Density Contributed from the Cosmological Constant
Institute of Scientific and Technical Information of China (English)
LIU Liao
2008-01-01
@@ Previously we introduce a new way to quantize the static Schwarzschild black hole (SSBH), there the SSBH was first treated as a single periodic Euclidean system and then the Bohr-Sommerfeld quantum condition of action was used to obtain a quantum theory of Schwarzschild black hole [Chin. Phys. Lett. (2004) 21 1887]. Here we try to extend the above method to quantize the static de Sitter (SDS) spacetime and establish a quantum theory of both SDS space and the energy density contributed from the cosmological constant.
Quantum bounds for gravitational de Sitter entropy and the Cardy-Verlinde formula
Nojiri, S; Odintsov, S D; Quevedo, H; Ryan, M P; Nojiri, Shin'ichi; Obregon, Octavio; Odintsov, Sergei D.; Quevedo, Hernando; Ryan, Mike P.
2001-01-01
We analyze different types of quantum corrections to the Cardy-Verlinde entropy formula in a Friedmann-Robertson-Walker universe and in an (anti)-de Sitter space. In all cases we show that quantum corrections can be represented by an effective cosmological constant which is then used to redefine the parameters entering the Cardy-Verlinde formula so that it becomes valid also with quantum corrections, a fact that we interpret as a further indication of its universality. A proposed relation between Cardy-Verlinde formula and the ADM Hamiltonian constraint is given.
Generic cosmic-censorship violation in anti-de Sitter space.
Hertog, Thomas; Horowitz, Gary T; Maeda, Kengo
2004-04-02
We consider (four-dimensional) gravity coupled to a scalar field with potential V(phi). The potential satisfies the positive energy theorem for solutions that asymptotically tend to a negative local minimum. We show that for a large class of such potentials, there is an open set of smooth initial data that evolve to naked singularities. Hence cosmic censorship does not hold for certain reasonable matter theories in asymptotically anti-de Sitter spacetimes. The asymptotically flat case is more subtle. We suspect that potentials with a local Minkowski minimum may similarly lead to violations of cosmic censorship in asymptotically flat spacetimes, but we do not have definite results.
Superluminal Neutrinos from Special Relativity with de Sitter Space-time Symmetry
Yan, Mu-Lin; Huang, Wei
2011-01-01
We explore the recent OPERA experiment of superluminal neutrinos in the framework of Special Relativity with de Sitter space-time symmetry (dS-SR). According to Einstein, the photon is treated as the massless particle in the SR mechanics. The meanings of the universal parameter $c$ and the photon velocity $c_{photon}$ in SR have been analyzed. $c$ can be determined by means of the velocity-composition law in SR kinematically. And $c_{photon}$ is determined by the dispersion relations of SR. It is revealed that $c=c_{photon}$ in Einstein's Special Relativity (E-SR), but $c\
The flux-scaling scenario. De Sitter uplift and axion inflation
Energy Technology Data Exchange (ETDEWEB)
Blumenhagen, Ralph; Damian, Cesar; Herschmann, Daniela; Sun, Rui [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Muenchen (Germany); Font, Anamaria [Departamento de Fisica, Centro de Fisica Teorica y Computacional, Facultad de Ciencias, Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)
2016-06-15
Non-geometric flux-scaling vacua provide promising starting points to realize axion monodromy inflation via the F-term scalar potential. We show that these vacua can be uplifted to Minkowski and de Sitter by adding an D3-brane or a D-term containing geometric and non-geometric fluxes. These uplifted non-supersymmetric models are analyzed with respect to their potential to realize axion monodromy inflation self-consistently. Admitting rational values of the fluxes, we construct examples with the required hierarchy of mass scales. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Reissner-Nordstr(o)m-de-Sitter-type Solution by a Gauge Theory of Gravity
Institute of Scientific and Technical Information of China (English)
V. Enache; Camelia Popa; V. P(a)un; M. Agop
2008-01-01
We use the theory based on a gravitational gauge group (Wu's model) to obtain a spherical symmetric solution of the field equations for the gravitational potential on a Minkowski spacetime. The gauge group, the gauge covariant derivative, the strength tensor of the gauge field, the gauge invariant Lagrangean with the cosmological constant, the field equations of the gauge potentials with a gravitational energy-momentum tensor as well as with a tensor of the field of a point like source are determined. Finally, a Reissner-Nordstr(o)m-de Sitter-type metric on the gauge group space is obtained.
Pinto-Neto, N
2000-01-01
A new prescription to calculate the total energies and angular momenta of asymptotically $(d+1)$-dimensional anti-de Sitter spacetimes is proposed. The method is based on an extension of the field theoretical approach to General Relativity to the case where there is an effective cosmological constant. A $(d-1)$-form $\\Omega$ is exhibited which, when integrated on asymptotic $(d-1)$-dimensional boundary surfaces, yields the values of those conserved quantities. The calculations are gauge independent once asymptotic conditions are not violated . Total energies and angular momenta of some known solutions in four and five dimensions are calculated agreeing with standard results.
A Review on the Cosmology of the de Sitter Horndeski Models
Directory of Open Access Journals (Sweden)
Nelson J. Nunes
2017-03-01
Full Text Available We review the most general scalar-tensor cosmological models with up to second-order derivatives in the field equations that have a fixed spatially flat de Sitter critical point independent of the material content or vacuum energy. This subclass of the Horndeski Lagrangian is capable of dynamically adjusting any value of the vacuum energy of the matter fields at the critical point. We present the cosmological evolution of the linear models and the non-linear models with shift symmetry. We come to the conclusion that the shift symmetric non-linear models can deliver a viable background compatible with current observations.
Solution of Dirac equation in Reissner-Nordström de Sitter space
Lyu, Yan; Cui, Song
2009-02-01
The radial parts of the Dirac equation between the outer black hole horizon and the cosmological horizon are solved in Reissner-Nordström de Sitter (RNdS) space numerically. An accurate approximation, the polynomial approximation, is used to approximate the modified tortoise coordinate \\hat r_* , which leads to the inverse function r = r(\\hat r_* ) and the potential V(\\hat r_* ). The potential V(\\hat r_* ) is replaced by a collection of step functions in sequence. Then the solution of the wave equation as well as the reflection and transmission coefficients is computed by a quantum mechanical method.
Spinor Field at the Phase Transition Point of Reissner-Nordström de Sitter Space
Lyu, Yan; Zhang, Li-Qing; Zheng, Wei; Pan, Qing-Chao
2010-08-01
The radial parts of Dirac equation between the outer black hole horizon and the cosmological horizon are solved in Reissner-Nordström de Sitter (RNdS) space when it is at the phase transition point. We use an accurate polynomial approximation to approximate the modified tortoise coordinate hat{r}_{*} in order to get the inverse function r=r(hat{r}_{*}) and the potential V(hat{r}_{*}). Then we use a quantum mechanical method to solve the wave equation numerically. We consider two cases, one is when the two horizons are lying close to each other, the other is when the two horizons are widely separated.
Entropy of Reissner–Nordström–de Sitter black hole
Directory of Open Access Journals (Sweden)
Li-Chun Zhang
2016-10-01
Full Text Available Based on the consideration that the black hole horizon and the cosmological horizon of Reissner–Nordström black hole in de Sitter space are not independent each other, we conjecture the total entropy of the system should have an extra term contributed from the entanglement between the two horizons, except for the sum of the two horizon entropies. Making use of the globally effective first law and the effective thermodynamic quantities, we derive the total entropy and find that it will diverge as the two horizons tend to coincide.
The fate of Schwarzschild-de Sitter Black Holes in $f(R)$ gravity
Addazi, Andrea
2016-01-01
The semiclassical effects of antievaporating black holes can be discussed in the framework of $f(R)$ gravity. In particular, the Bousso-Hawking-Nojiri-Odinstov antievaporation instability of degenerate Schwarzschild-de Sitter black holes (the so called Nariai space-time) leads to a dynamical increasing of black hole horizon in $f(R)$ gravity. This phenomenon causes the following transition: emitting marginally trapped surfaces become space-like surfaces before the effective Bekenstein-Hawking emission time. As a consequence, Bousso-Hawking thermal radiation cannot be emitted in an antievaporating Nariai black hole. Possible implications in cosmology and black hole physics are also discussed.
Greybody factor of scalar field from Reissner-Nordstrom-de Sitter black hole
Ahmed, Jamil
2016-01-01
In this work we derive a general expression for the greybody factor of non-minimally coupled scalar fields in Reissner-Nordstr{\\"o}m-de Sitter spacetime in low frequency approximation. In particular case of zero momentum, greybody factor tends to zero in low frequency limit as frequency squared goes to zero for non-vanishing coupling. We also elaborate the significance of the results by giving formulae of differential energy rate and general absorption cross section. The greybody factor gives insight into the spectrum of Hawking radiations.
The Dirac particle on central backgrounds and the anti-de Sitter oscillator
Cotaescu, I I
1998-01-01
It is shown that, for spherically symmetric static backgrounds, a simple reduced Dirac equation can be obtained by using the Cartesian tetrad gauge in Cartesian holonomic coordinates. This equation is manifestly covariant under rotations so that the spherical coordinates can be separated in terms of angular spinors like in special relativity, obtaining a pair of radial equations and a specific form of the radial scalar product. As an example, we analytically solve the anti-de Sitter oscillator giving the formula of the energy levels and the form of the corresponding eigenspinors.
Quantum Scalar Corrections to the Gravitational Potentials on de Sitter Background
Park, Sohyun; Woodard, R P
2015-01-01
We employ the graviton self-energy induced by a massless, minimally coupled (MMC) scalar on de Sitter background to compute the quantum corrections to the gravitational potentials of a static point particle with a mass $M$. The Schwinger-Keldysh formalism is used to derive real and causal effective field equations. When evaluated at the one-loop order, the gravitational potentials exhibit a secular decrease in the observed gravitational coupling $G$. This can also be interpreted as a (time dependent) anti-screening of the mass $M$.
A note on conformally compactified connection dynamics tailored for anti-de Sitter space
Bodendorfer, N.
2016-12-01
A framework conceptually based on the conformal techniques employed to study the structure of the gravitational field at infinity is set up in the context of loop quantum gravity to describe asymptotically anti-de Sitter quantum spacetimes. A conformal compactification of the spatial slice is performed, which, in terms of the rescaled metric, has now finite volume, and can thus be conveniently described by spin networks states. The conformal factor used is a physical scalar field, which has the necessary asymptotics for many asymptotically AdS black hole solutions.
Symmetron and de Sitter attractor in a teleparallel model of cosmology
Mohseni Sadjadi, H.
2017-01-01
In the teleparallel framework of cosmology, a quintessence with non-minimal couplings to the scalar torsion and a boundary term is considered. A conformal coupling to matter density is also taken into account. It is shown that the model can describe onset of cosmic acceleration after an epoch of matter dominated era, where dark energy is negligible, via Z2 symmetry breaking. While the conformal coupling holds the Universe in a state with zero dark energy density in the early epoch, the non-minimal couplings lead the Universe to a stable state with de Sitter expansion at late time.
Effective potential and geodesic motion in Kerr-de Sitter space-time
Poudel, P C
2013-01-01
In the present work, geodesic trajectories in Kerr-de Sitter geometry is analyzed. From the mathematical solution of Lagrangian formalism appropriate to motions in the equatorial plane (for which 'theta' = 0 and 'theta' = (constant)= pi/2) can give potential energy of massive and massless particles for rotating axisymetric black hole. From this, for a particular value of cosmological constant, Kerr parameter, mass, angular momentum and impact parameter; variation of potential with distance can be found. Similarly, for a particular value of cosmological constant, mass and Kerr parameter; variation of velocity with distance can be found.
On solutions of the Pauli equation in non-static de Sitter metrics
Ovsiyuk, E M
2015-01-01
A particle with spin 1/2 is investigated both in expanding and oscillating cosmological de Sitter models. It is shown that these space-time geometries admit existence of the non-relativistic limit in the covariant Dirac equation. Procedure for transition to the Pauli approximation is conducted in the equations in the variables $(t, r)$, obtained after separating the angular dependence of $(\\theta, \\phi)$ from the wave function. The non-relativistic systems of equations in the variables $(t, r)$ is solved exactly in both models. The constructed wave functions do not represent stationary states with fixed energy, however the corresponding probability density does not depend on the time.
The algebra of supertraces for 2+1 super de Sitter gravity
Urrutia, L. F.; Waelbroeck, H.; Zertuche, F.
1993-01-01
The algebra of the observables for 2+1 super de Sitter gravity, for one genus of the spatial surface is calculated. The algebra turns out to be an infinite Lie algebra subject to non-linear constraints. The constraints are solved explicitly in terms of five independent complex supertraces. These variables are the true degrees of freedom of the system and their quantized algebra generates a new structure which is referred to as a 'central extension' of the quantum algebra SU(2)q.
Exact gravitational lensing in conformal gravity and Schwarzschild-de Sitter spacetime
Lim, Yen-Kheng
2016-01-01
An exact solution is obtained for the gravitational bending of light in static, spherically symmetric metrics which includes the Schwarzschild-de Sitter (SdS) spacetime and also the Mannheim-Kazanas (MK) metric of conformal Weyl gravity. From the exact solution, we obtain a small bending-angle approximation for a lens system where the source, lens and observer are co-aligned. This expansion improves previous calculations where we systematically avoid parameter ranges which correspond to non-existent null trajectories. The linear coefficient $\\gamma$ characteristic to conformal gravity is shown to contribute enhanced deflection compared to the angle predicted by General Relativity for small $\\gamma$.