Topologically Massive Higher Spin Gravity
Bagchi, A.; Lal, S.; Saha, A.; Sahoo, B.
2011-01-01
We look at the generalisation of topologically massive gravity (TMG) to higher spins, specifically spin-3. We find a special "chiral" point for the spin-three, analogous to the spin-two example, which actually coincides with the usual spin-two chiral point. But in contrast to usual TMG, there is the
Spin-3 topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Chen Bin, E-mail: bchen01@pku.edu.cn [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center for High Energy Physics, Peking University, Beijing 100871 (China); Long Jiang, E-mail: longjiang0301@gmail.com [Department of Physics, and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Wu Junbao, E-mail: wujb@ihep.ac.cn [Institute of High Energy Physics, and Theoretical Physics Center for Science Facilities, Chinese Academy of Sciences, Beijing 100049 (China)
2011-11-24
In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS{sub 3} vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W{sub 3} algebra and central charge c{sub R}=3l/G.
Circular symmetry in topologically massive gravity
International Nuclear Information System (INIS)
Deser, S; Franklin, J
2010-01-01
We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null. (note)
NOTE: Circular symmetry in topologically massive gravity
Deser, S.; Franklin, J.
2010-05-01
We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null.
Circular symmetry in topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Deser, S [Physics Department, Brandeis University, Waltham, MA 02454 (United States); Franklin, J, E-mail: deser@brandeis.ed, E-mail: jfrankli@reed.ed [Reed College, Portland, OR 97202 (United States)
2010-05-21
We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null. (note)
Holographically viable extensions of topologically massive and minimal massive gravity?
Altas, Emel; Tekin, Bayram
2016-01-01
Recently [E. Bergshoeff et al., Classical Quantum Gravity 31, 145008 (2014)], an extension of the topologically massive gravity (TMG) in 2 +1 dimensions, dubbed as minimal massive gravity (MMG), which is free of the bulk-boundary unitarity clash that inflicts the former theory and all the other known three-dimensional theories, was found. Field equations of MMG differ from those of TMG at quadratic terms in the curvature that do not come from the variation of an action depending on the metric alone. Here we show that MMG is a unique theory and there does not exist a deformation of TMG or MMG at the cubic and quartic order (and beyond) in the curvature that is consistent at the level of the field equations. The only extension of TMG with the desired bulk and boundary properties having a single massive degree of freedom is MMG.
Topologically massive gravity and its conformal limit
International Nuclear Information System (INIS)
Ertl, S.
2012-01-01
Three dimensional gravity has been known for some time to be a playground for testing ideas and problems of higher dimensional gravitational theories. Nevertheless its status as a toy model for quantum gravity is still uncertain. Already in 1986 Brown and Henneaux discovered that three dimensional quantum gravity with negative cosmological constant is dual to a two dimensional conformal field theory (CFT) in the sense that the Hilbert space must fall into unitary representation of two copies of the Virasoro algebra. They obtained, in quantizing this theory, an asymptotic Virasoro algebra with central charges c L =c R =(3 l)/(2 G N ), where G N is Newton's constant and ℓ parameterizes the cosmological constant. Almost ten years later black hole solutions for this three dimensional theory were discovered by Banados, Teitelboim and Zanelli. In the same period of time further milestones of relevance for this work have been established: the AdS/CFT correspondence by Maldacena in 1997 and the proposal by Witten in 2007 to define three dimensional quantum gravity in terms of its dual CFT. Over the last few years many attempts have been made to construct gravitational theories in three dimensions that could serve as toy models for quantum gravity. Since a pure Einstein-Hilbert action with a negative cosmological constant lacks additional degrees of freedom one can remedy this by adding a gravitational Chern-Simons term. This results in a theory that exhibits black holes and gravitons and is called topologically massive gravity (TMG). The first part of this thesis deals with finding exact solutions of TMG. This is an interesting problem already at the classical level since non-trivial solutions to the equations of motion are hard to find and only few are known. An efficient way to find solutions is to dimensionally reduce the theory by using two commuting Killing vectors. This results in a (0+1)-dimensional model in which it is then possible to classify all stationary axi
Bosonization of fermions coupled to topologically massive gravity
Fradkin, Eduardo; Moreno, Enrique F.; Schaposnik, Fidel A.
2014-03-01
We establish a duality between massive fermions coupled to topologically massive gravity (TMG) in d=3 space-time dimensions and a purely gravity theory which also will turn out to be a TMG theory but with different parameters: the original graviton mass in the TMG theory coupled to fermions picks up a contribution from fermion bosonization. We obtain explicit bosonization rules for the fermionic currents and for the energy-momentum tensor showing that the identifications do not depend explicitly on the parameters of the theory. These results are the gravitational analog of the results for 2+1 Abelian and non-Abelian bosonization in flat space-time.
Bosonization of fermions coupled to topologically massive gravity
International Nuclear Information System (INIS)
Fradkin, Eduardo; Moreno, Enrique F.; Schaposnik, Fidel A.
2014-01-01
We establish a duality between massive fermions coupled to topologically massive gravity (TMG) in d=3 space–time dimensions and a purely gravity theory which also will turn out to be a TMG theory but with different parameters: the original graviton mass in the TMG theory coupled to fermions picks up a contribution from fermion bosonization. We obtain explicit bosonization rules for the fermionic currents and for the energy–momentum tensor showing that the identifications do not depend explicitly on the parameters of the theory. These results are the gravitational analog of the results for 2+1 Abelian and non-Abelian bosonization in flat space–time.
Bosonization of fermions coupled to topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Fradkin, Eduardo [Department of Physics and Institute for Condensed Matter Theory, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801-3080 (United States); Moreno, Enrique F. [Department of Physics, Northeastern University, Boston, MA 02115 (United States); Schaposnik, Fidel A. [Departamento de Física, Universidad Nacional de La Plata, Instituto de Física La Plata, C.C. 67, 1900 La Plata (Argentina)
2014-03-07
We establish a duality between massive fermions coupled to topologically massive gravity (TMG) in d=3 space–time dimensions and a purely gravity theory which also will turn out to be a TMG theory but with different parameters: the original graviton mass in the TMG theory coupled to fermions picks up a contribution from fermion bosonization. We obtain explicit bosonization rules for the fermionic currents and for the energy–momentum tensor showing that the identifications do not depend explicitly on the parameters of the theory. These results are the gravitational analog of the results for 2+1 Abelian and non-Abelian bosonization in flat space–time.
Black hole mass and angular momentum in topologically massive gravity
International Nuclear Information System (INIS)
Bouchareb, Adel; Clement, Gerard
2007-01-01
We extend the Abbott-Deser-Tekin approach to the computation of the Killing charge for a solution of topologically massive gravity (TMG) linearized around an arbitrary background. This is then applied to evaluate the mass and angular momentum of black hole solutions of TMG with non-constant curvature asymptotics. The resulting values, together with the appropriate black hole entropy, fit nicely into the first law of black hole thermodynamics
Black hole mass and angular momentum in topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Bouchareb, Adel; Clement, Gerard [Laboratoire de Physique Theorique LAPTH (CNRS), BP 110, F-74941 Annecy-le-Vieux cedex (France)
2007-11-21
We extend the Abbott-Deser-Tekin approach to the computation of the Killing charge for a solution of topologically massive gravity (TMG) linearized around an arbitrary background. This is then applied to evaluate the mass and angular momentum of black hole solutions of TMG with non-constant curvature asymptotics. The resulting values, together with the appropriate black hole entropy, fit nicely into the first law of black hole thermodynamics.
Topologically massive gravity and Ricci-Cotton flow
Energy Technology Data Exchange (ETDEWEB)
Lashkari, Nima; Maloney, Alexander, E-mail: lashkari@physics.mcgill.ca, E-mail: maloney@physics.mcgill.ca [McGill Physics Department, 3600 rue University, Montreal, QC H3A 2T8 (Canada)
2011-05-21
We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.
Topologically massive gravity and Ricci-Cotton flow
International Nuclear Information System (INIS)
Lashkari, Nima; Maloney, Alexander
2011-01-01
We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.
Asymptotically anti-de Sitter spacetimes in topologically massive gravity
International Nuclear Information System (INIS)
Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo
2009-01-01
We consider asymptotically anti-de Sitter spacetimes in three-dimensional topologically massive gravity with a negative cosmological constant, for all values of the mass parameter μ (μ≠0). We provide consistent boundary conditions that accommodate the recent solutions considered in the literature, which may have a slower falloff than the one relevant for general relativity. These conditions are such that the asymptotic symmetry is in all cases the conformal group, in the sense that they are invariant under asymptotic conformal transformations and that the corresponding Virasoro generators are finite. It is found that, at the chiral point |μl|=1 (where l is the anti-de Sitter radius), allowing for logarithmic terms (absent for general relativity) in the asymptotic behavior of the metric makes both sets of Virasoro generators nonzero even though one of the central charges vanishes.
Kundt spacetimes as solutions of topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Chow, David D K; Pope, C N; Sezgin, Ergin [George P and Cynthia W Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States)
2010-05-21
We obtain new solutions of topologically massive gravity. We find the general Kundt solutions, which in three dimensions are spacetimes admitting an expansion-free null geodesic congruence. The solutions are generically of algebraic type II, but special cases are types III, N or D. Those of type D are the known spacelike-squashed AdS{sub 3} solutions and of type N are the known AdS pp-waves or new solutions. Those of types II and III are the first known solutions of these algebraic types. We present explicitly the Kundt solutions that are constant scalar invariant (CSI) spacetimes, for which all scalar polynomial curvature invariants are constant, whereas for the general case, we reduce the field equations to a series of ordinary differential equations. The CSI solutions of types II and III are deformations of spacelike-squashed AdS{sub 3} and the round AdS{sub 3}, respectively.
Classical aspects of higher spin topologically massive gravity
International Nuclear Information System (INIS)
Chen Bin; Long Jiang; Zhang Jiandong
2012-01-01
We study the classical solutions of three-dimensional topologically massive gravity (TMG) and its higher spin generalization, in the first-order formulation. The action of higher spin TMG has been proposed by Chen and Long (2011 J. High Energy Phys. JHEP12(2011)114) to be of a Chern–Simons-like form. The equations of motion are more complicated than the ones in pure higher spin AdS 3 gravity, but are still tractable. As all the solutions in higher spin gravity are automatically the solutions of higher spin TMG, we focus on other solutions. We manage to find the AdS pp-wave solutions with higher spin hair and find that the non-vanishing higher spin fields may or may not modify the pp-wave geometry. In order to discuss the warped spacetime, we introduce the notion of a special Killing vector, which is defined to be the symmetry on the frame-like fields. We reproduce various warped spacetimes of TMG in our framework, with the help of special Killing vectors. (paper)
Topologically massive gravity and the AdS/CFT correspondence
International Nuclear Information System (INIS)
Skenderis, Kostas; Taylor, Marika; Rees, Balt C. van
2009-01-01
We set up the AdS/CFT correspondence for topologically massive gravity (TMG) in three dimensions. The first step in this procedure is to determine the appropriate fall off conditions at infinity. These cannot be fixed a priori as they depend on the bulk theory under consideration and are derived by solving asymptotically the non-linear field equations. We discuss in detail the asymptotic structure of the field equations for TMG, showing that it contains leading and subleading logarithms, determine the map between bulk fields and CFT operators, obtain the appropriate counterterms needed for holographic renormalization and compute holographically one- and two-point functions at and away from the 'chiral point' (μ = 1). The 2-point functions at the chiral point are those of a logarithmic CFT (LCFT) with c L = 0,c R = 3l/G N and b = -3l/G N , where b is a parameter characterizing different c = 0 LCFTs. The bulk correlators away from the chiral point (μ ≠ 1) smoothly limit to the LCFT ones as μ → 1. Away from the chiral point, the CFT contains a state of negative norm and the expectation value of the energy momentum tensor in that state is also negative, reflecting a corresponding bulk instability due to negative energy modes.
de Rham, Claudia
2014-01-01
We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali–Gabadadze–Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware–Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alt...
Topologically massive supergravity
Directory of Open Access Journals (Sweden)
S. Deser
1983-01-01
Full Text Available The locally supersymmetric extension of three-dimensional topologically massive gravity is constructed. Its fermionic part is the sum of the (dynamically trivial Rarita-Schwinger action and a gauge-invariant topological term, of second derivative order, analogous to the gravitational one. It is ghost free and represents a single massive spin 3/2 excitation. The fermion-gravity coupling is minimal and the invariance is under the usual supergravity transformations. The system's energy, as well as that of the original topological gravity, is therefore positive.
Quasi-local conserved charges of spin-3 topologically massive gravity
Directory of Open Access Journals (Sweden)
M.R. Setare
2016-08-01
Full Text Available In this paper we obtain conserved charges of spin-3 topologically massive gravity by using a quasi-local formalism. We find a general formula to calculate conserved charge of the spin-3 topologically massive gravity which corresponds to a Killing vector field ξ. We show that this general formula reduces to the previous one for the ordinary spin-3 gravity presented in [18] when we take into account only transformation under diffeomorphism, without considering generalized Lorentz gauge transformation (i.e. λξ=0, and by taking 1μ→0. Then we obtain a general formula for the entropy of black hole solutions of the spin-3 topologically massive gravity. Finally we apply our formalism to calculate energy, angular momentum and entropy of a special black hole solution and we find that obtained results are consistent with previous results in the limiting cases. Moreover our results for energy, angular momentum and entropy are consistent with the first law of black hole mechanics.
Anomalies and Hawking fluxes from the black holes of topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Porfyriadis, Achilleas P. [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)], E-mail: apporfyr@mit.edu
2009-05-11
The anomaly cancellation method proposed by Wilczek et al. is applied to the black holes of topologically massive gravity (TMG) and topologically massive gravito-electrodynamics (TMGE). Thus the Hawking temperature and fluxes of the ACL and ACGL black holes are found. The Hawking temperatures obtained agree with the surface gravity formula. Both black holes are rotating and this gives rise to appropriate terms in the effective U(1) gauge field of the reduced (1+1)-dimensional theory. It is found that the terms in this U(1) gauge field correspond exactly to the correct angular velocities on the horizon of both black holes as well as the correct electrostatic potential of the ACGL black hole. So the results for the Hawking fluxes derived here from the anomaly cancellation method, are in complete agreement with the ones obtained from integrating the Planck distribution.
International Nuclear Information System (INIS)
Moutsopoulos, George
2013-01-01
We solve the equations of topologically massive gravity (TMG) with a potentially non-vanishing cosmological constant for homogeneous metrics without isotropy. We only reproduce known solutions. We also discuss their homogeneous deformations, possibly with isotropy. We show that de Sitter space and hyperbolic space cannot be infinitesimally homogeneously deformed in TMG. We clarify some of their Segre–Petrov types and discuss the warped de Sitter spacetime. (paper)
Moutsopoulos, George
2013-06-01
We solve the equations of topologically massive gravity (TMG) with a potentially non-vanishing cosmological constant for homogeneous metrics without isotropy. We only reproduce known solutions. We also discuss their homogeneous deformations, possibly with isotropy. We show that de Sitter space and hyperbolic space cannot be infinitesimally homogeneously deformed in TMG. We clarify some of their Segre-Petrov types and discuss the warped de Sitter spacetime.
Stability of warped AdS3 vacua of topologically massive gravity
International Nuclear Information System (INIS)
Anninos, Dionysios; Esole, Mboyo; Guica, Monica
2009-01-01
AdS 3 vacua of topologically massive gravity (TMG) have been shown to be perturbatively unstable for all values of the coupling constant except the chiral point μl = 1. We study the possibility that the warped vacua of TMG, which exist for all values of μ, are stable under linearized perturbations. In this paper, we show that spacelike warped AdS 3 vacua with Compere-Detournay boundary conditions are indeed stable in the range μl>3. This is precisely the range in which black hole solutions arise as discrete identifications of the warped AdS 3 vacuum. The situation somewhat resembles chiral gravity: although negative energy modes do exist, they are all excluded by the boundary conditions, and the perturbative spectrum solely consists of boundary (pure large gauge) gravitons.
Asymptotically warped anti-de Sitter spacetimes in topologically massive gravity
International Nuclear Information System (INIS)
Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo
2011-01-01
Asymptotically warped AdS spacetimes in topologically massive gravity with negative cosmological constant are considered in the case of spacelike stretched warping, where black holes have been shown to exist. We provide a set of asymptotic conditions that accommodate solutions in which the local degree of freedom (the ''massive graviton'') is switched on. An exact solution with this property is explicitly exhibited and possesses a slower falloff than the warped AdS black hole. The boundary conditions are invariant under the semidirect product of the Virasoro algebra with a u(1) current algebra. We show that the canonical generators are integrable and finite. When the graviton is not excited, our analysis is compared and contrasted with earlier results obtained through the covariant approach to conserved charges. In particular, we find agreement with the conserved charges of the warped AdS black holes as well as with the central charges in the algebra.
International Nuclear Information System (INIS)
Hendi, S.H.; Eslam Panah, B.; Panahiyan, S.
2017-01-01
Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
Directory of Open Access Journals (Sweden)
S.H. Hendi
2017-06-01
Full Text Available Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
On the Faddeev-Jackiw symplectic framework for topologically massive gravity
Energy Technology Data Exchange (ETDEWEB)
Escalante, Alberto [Benemerita Universidad Autonoma de Puebla, Instituto de Fisica, Puebla (Mexico); Rodriguez-Tzompantzi, Omar [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias Fisico Matematicas, Puebla (Mexico)
2016-10-15
The dynamical structure of topologically massive gravity in the context of the Faddeev-Jackiw symplectic approach is studied. It is shown that this method allows us to avoid some ambiguities arising in the study of the gauge structure via the Dirac formalism. In particular, the complete set of constraints and the generators of the gauge symmetry of the theory are obtained straightforwardly via the zero modes of the symplectic matrix. In order to obtain the generalized Faddeev-Jackiw brackets and calculate the local physical degrees of freedom of this model, an appropriate gauge-fixing procedure is introduced. Finally, the similarities and relative advantages between the Faddeev-Jackiw method and Dirac's formalism are briefly discussed. (orig.)
Topological massive sigma models
International Nuclear Information System (INIS)
Lambert, N.D.
1995-01-01
In this paper we construct topological sigma models which include a potential and are related to twisted massive supersymmetric sigma models. Contrary to a previous construction these models have no central charge and do not require the manifold to admit a Killing vector. We use the topological massive sigma model constructed here to simplify the calculation of the observables. Lastly it is noted that this model can be viewed as interpolating between topological massless sigma models and topological Landau-Ginzburg models. ((orig.))
International Nuclear Information System (INIS)
Bergshoeff, Eric; Merbis, Wout; Hohm, Olaf; Routh, Alasdair J; Townsend, Paul K
2014-01-01
We present an alternative to topologically massive gravity (TMG) with the same ‘minimal’ bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new ‘minimal massive gravity’ has both a positive energy graviton and positive central charges for the asymptotic AdS-boundary conformal algebra. (paper)
Massive gravity from bimetric gravity
International Nuclear Information System (INIS)
Baccetti, Valentina; Martín-Moruno, Prado; Visser, Matt
2013-01-01
We discuss the subtle relationship between massive gravity and bimetric gravity, focusing particularly on the manner in which massive gravity may be viewed as a suitable limit of bimetric gravity. The limiting procedure is more delicate than currently appreciated. Specifically, this limiting procedure should not unnecessarily constrain the background metric, which must be externally specified by the theory of massive gravity itself. The fact that in bimetric theories one always has two sets of metric equations of motion continues to have an effect even in the massive gravity limit, leading to additional constraints besides the one set of equations of motion naively expected. Thus, since solutions of bimetric gravity in the limit of vanishing kinetic term are also solutions of massive gravity, but the contrary statement is not necessarily true, there is no complete continuity in the parameter space of the theory. In particular, we study the massive cosmological solutions which are continuous in the parameter space, showing that many interesting cosmologies belong to this class. (paper)
Bergshoeff, Eric A.; Hohm, Olaf; Townsend, Paul K.
2012-01-01
We present a brief review of New Massive Gravity, which is a unitary theory of massive gravitons in three dimensions obtained by considering a particular combination of the Einstein-Hilbert and curvature squared terms.
More on asymptotically anti-de Sitter spaces in topologically massive gravity
International Nuclear Information System (INIS)
Henneaux, Marc; Martinez, Cristian; Troncoso, Ricardo
2010-01-01
Recently, the asymptotic behavior of three-dimensional anti-de Sitter (AdS) gravity with a topological mass term was investigated. Boundary conditions were given that were asymptotically invariant under the two dimensional conformal group and that included a falloff of the metric sufficiently slow to consistently allow pp-wave type of solutions. Now, pp waves can have two different chiralities. Above the chiral point and at the chiral point, however, only one chirality can be considered, namely, the chirality that has the milder behavior at infinity. The other chirality blows up faster than AdS and does not define an asymptotically AdS spacetime. By contrast, both chiralities are subdominant with respect to the asymptotic behavior of AdS spacetime below the chiral point. Nevertheless, the boundary conditions given in the earlier treatment only included one of the two chiralities (which could be either one) at a time. We investigate in this paper whether one can generalize these boundary conditions in order to consider simultaneously both chiralities below the chiral point. We show that this is not possible if one wants to keep the two-dimensional conformal group as asymptotic symmetry group. Hence, the boundary conditions given in the earlier treatment appear to be the best possible ones compatible with conformal symmetry. In the course of our investigations, we provide general formulas controlling the asymptotic charges for all values of the topological mass (not just below the chiral point).
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H., E-mail: hendi@shirazu.ac.ir [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha (Iran, Islamic Republic of); Eslam Panah, B. [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Panahiyan, S. [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Physics Department, Shahid Beheshti University, Tehran 19839 (Iran, Islamic Republic of)
2017-06-10
Violation of Lorentz invariancy in the high energy quantum gravity motivates one to consider an energy dependent spacetime with massive deformation of standard general relativity. In this paper, we take into account an energy dependent metric in the context of a massive gravity model to obtain exact solutions. We investigate the geometry of black hole solutions and also calculate the conserved and thermodynamic quantities, which are fully reproduced by the analysis performed with the standard techniques. After examining the validity of the first law of thermodynamics, we conduct a study regarding the effects of different parameters on thermal stability of the solutions. In addition, we employ the relation between cosmological constant and thermodynamical pressure to study the possibility of phase transition. Interestingly, we will show that for the specific configuration considered in this paper, van der Waals like behavior is observed for different topology. In other words, for flat and hyperbolic horizons, similar to spherical horizon, a second order phase transition and van der Waals like behavior are observed. Furthermore, we use geometrical method to construct phase space and study phase transition and bound points for these black holes. Finally, we obtain critical values in extended phase space through the use of a new method.
International Nuclear Information System (INIS)
Faria, F. F.
2014-01-01
We construct a massive theory of gravity that is invariant under conformal transformations. The massive action of the theory depends on the metric tensor and a scalar field, which are considered the only field variables. We find the vacuum field equations of the theory and analyze its weak-field approximation and Newtonian limit.
International Nuclear Information System (INIS)
Setare, M R; Kamali, V
2011-01-01
We show that a BTZ black hole solution of cosmological topological massive gravity has a hidden conformal symmetry. In this regard, we consider the wave equation of a massless scalar field propagating in BTZ spacetime and find that the wave equation could be written in terms of the SL(2, R) quadratic Casimir. From the conformal coordinates, the temperatures of the dual conformal field theories (CFTs) could be read directly. Moreover, we compute the microscopic entropy of the dual CFT by the Cardy formula and find a perfect match to the Bekenstein-Hawking entropy of a BTZ black hole. Then, we consider Galilean conformal algebras (GCA), which arises as a contraction of relativistic conformal algebras (x → εx, t → t, ε → 0). We show that there is a correspondence between GCA 2 on the boundary and contracted BTZ in the bulk. For this purpose we obtain the central charges and temperatures of GCA 2 . Then, we compute the microscopic entropy of the GCA 2 by the Cardy formula and find a perfect match to the Bekenstein-Hawking entropy of a BTZ black hole in a non-relativistic limit. The absorption cross section of a near-region scalar field also matches the microscopic absorption cross section of the dual GCA 2 . So we find further evidence that shows correspondence between a contracted BTZ black hole and two-dimensional GCA.
Dubovsky, S L
2004-01-01
We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group using the explicitly covariant language. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity can be described by a consistent low-energy effective theory with cutoff $\\sim\\sqrt{mM_{Pl}}$ free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz--Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of ...
Topological strings from Liouville gravity
International Nuclear Information System (INIS)
Ishibashi, N.; Li, M.
1991-01-01
We study constrained SU(2) WZW models, which realize a class of two-dimensional conformal field theories. We show that they give rise to topological gravity coupled to the topological minimal models when they are coupled to Liouville gravity. (orig.)
Topological gravity with minimal matter
International Nuclear Information System (INIS)
Li Keke
1991-01-01
Topological minimal matter, obtained by twisting the minimal N = 2 supeconformal field theory, is coupled to two-dimensional topological gravity. The free field formulation of the coupled system allows explicit representations of BRST charge, physical operators and their correlation functions. The contact terms of the physical operators may be evaluated by extending the argument used in a recent solution of topological gravity without matter. The consistency of the contact terms in correlation functions implies recursion relations which coincide with the Virasoro constraints derived from the multi-matrix models. Topological gravity with minimal matter thus provides the field theoretic description for the multi-matrix models of two-dimensional quantum gravity. (orig.)
Quasi-topological Ricci polynomial gravities
Li, Yue-Zhou; Liu, Hai-Shan; Lü, H.
2018-02-01
Quasi-topological terms in gravity can be viewed as those that give no contribution to the equations of motion for a special subclass of metric ansätze. They therefore play no rôle in constructing these solutions, but can affect the general perturbations. We consider Einstein gravity extended with Ricci tensor polynomial invariants, which admits Einstein metrics with appropriate effective cosmological constants as its vacuum solutions. We construct three types of quasi-topological gravities. The first type is for the most general static metrics with spherical, toroidal or hyperbolic isometries. The second type is for the special static metrics where g tt g rr is constant. The third type is the linearized quasitopological gravities on the Einstein metrics. We construct and classify results that are either dependent on or independent of dimensions, up to the tenth order. We then consider a subset of these three types and obtain Lovelock-like quasi-topological gravities, that are independent of the dimensions. The linearized gravities on Einstein metrics on all dimensions are simply Einstein and hence ghost free. The theories become quasi-topological on static metrics in one specific dimension, but non-trivial in others. We also focus on the quasi-topological Ricci cubic invariant in four dimensions as a specific example to study its effect on holography, including shear viscosity, thermoelectric DC conductivities and butterfly velocity. In particular, we find that the holographic diffusivity bounds can be violated by the quasi-topological terms, which can induce an extra massive mode that yields a butterfly velocity unbound above.
Kundt solutions of minimal massive 3D gravity
Deger, Nihat Sadik; Sarıoǧlu, Ã.-zgür
2015-11-01
We construct Kundt solutions of minimal massive gravity theory and show that, similar to topologically massive gravity (TMG), most of them are constant scalar invariant (CSI) spacetimes that correspond to deformations of round and warped (A)dS. We also find an explicit non-CSI Kundt solution at the merger point. Finally, we give their algebraic classification with respect to the traceless Ricci tensor (Segre classification) and show that their Segre types match with the types of their counterparts in TMG.
Exact Solutions in 3D New Massive Gravity
Ahmedov, Haji; Aliev, Alikram N.
2011-01-01
We show that the field equations of new massive gravity (NMG) consist of a massive (tensorial) Klein-Gordon-type equation with a curvature-squared source term and a constraint equation. We also show that, for algebraic type D and N spacetimes, the field equations of topologically massive gravity (TMG) can be thought of as the “square root” of the massive Klein-Gordon-type equation. Using this fact, we establish a simple framework for mapping all types D and N solutions of TMG into NMG. Finally, we present new examples of types D and N solutions to NMG.
Minimal theory of massive gravity
International Nuclear Information System (INIS)
De Felice, Antonio; Mukohyama, Shinji
2016-01-01
We propose a new theory of massive gravity with only two propagating degrees of freedom. While the homogeneous and isotropic background cosmology and the tensor linear perturbations around it are described by exactly the same equations as those in the de Rham–Gabadadze–Tolley (dRGT) massive gravity, the scalar and vector gravitational degrees of freedom are absent in the new theory at the fully nonlinear level. Hence the new theory provides a stable nonlinear completion of the self-accelerating cosmological solution that was originally found in the dRGT theory. The cosmological solution in the other branch, often called the normal branch, is also rendered stable in the new theory and, for the first time, makes it possible to realize an effective equation-of-state parameter different from (either larger or smaller than) −1 without introducing any extra degrees of freedom.
Minimal theory of massive gravity
Directory of Open Access Journals (Sweden)
Antonio De Felice
2016-01-01
Full Text Available We propose a new theory of massive gravity with only two propagating degrees of freedom. While the homogeneous and isotropic background cosmology and the tensor linear perturbations around it are described by exactly the same equations as those in the de Rham–Gabadadze–Tolley (dRGT massive gravity, the scalar and vector gravitational degrees of freedom are absent in the new theory at the fully nonlinear level. Hence the new theory provides a stable nonlinear completion of the self-accelerating cosmological solution that was originally found in the dRGT theory. The cosmological solution in the other branch, often called the normal branch, is also rendered stable in the new theory and, for the first time, makes it possible to realize an effective equation-of-state parameter different from (either larger or smaller than −1 without introducing any extra degrees of freedom.
Vaidya spacetime in massive gravity's rainbow
Directory of Open Access Journals (Sweden)
Yaghoub Heydarzade
2017-11-01
Full Text Available In this paper, we will analyze the energy dependent deformation of massive gravity using the formalism of massive gravity's rainbow. So, we will use the Vainshtein mechanism and the dRGT mechanism for the energy dependent massive gravity, and thus analyze a ghost free theory of massive gravity's rainbow. We study the energy dependence of a time-dependent geometry, by analyzing the radiating Vaidya solution in this theory of massive gravity's rainbow. The energy dependent deformation of this Vaidya metric will be performed using suitable rainbow functions.
Solid holography and massive gravity
International Nuclear Information System (INIS)
Alberte, Lasma; Baggioli, Matteo; Khmelnitsky, Andrei; Pujolàs, Oriol
2016-01-01
Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric response. We show that the types of response that can be consistently described within this framework is much wider than what is captured by the narrow class of models mostly considered so far.
Solid holography and massive gravity
Energy Technology Data Exchange (ETDEWEB)
Alberte, Lasma [Abdus Salam International Centre for Theoretical Physics,Strada Costiera 11, 34151, Trieste (Italy); Baggioli, Matteo [Institut de Física d’Altes Energies (IFAE),The Barcelona Institute of Science and Technology (BIST), Campus UAB, 08193 Bellaterra, Barcelona (Spain); Department of Physics, Institute for Condensed Matter Theory, University of Illinois,1110 W. Green Street, Urbana, IL 61801 (United States); Khmelnitsky, Andrei [Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151, Trieste (Italy); Pujolàs, Oriol [Institut de Física d’Altes Energies (IFAE),The Barcelona Institute of Science and Technology (BIST), Campus UAB, 08193 Bellaterra, Barcelona (Spain)
2016-02-17
Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric response. We show that the types of response that can be consistently described within this framework is much wider than what is captured by the narrow class of models mostly considered so far.
Black holes in massive gravity as heat engines
Hendi, S. H.; Eslam Panah, B.; Panahiyan, S.; Liu, H.; Meng, X.-H.
2018-06-01
The paper at hand studies the heat engine provided by black holes in the presence of massive gravity. The main motivation is to investigate the effects of massive gravity on different properties of the heat engine. It will be shown that massive gravity parameters modify the efficiency of engine on a significant level. Furthermore, it will be pointed out that it is possible to have a heat engine for non-spherical black holes in massive gravity, and therefore, we will study the effects of horizon topology on the properties of heat engine. Surprisingly, it will be shown that the highest efficiency for the heat engine belongs to black holes with the hyperbolic horizon, while the lowest one belongs to the spherical black holes.
Nonsingular universe in massive gravity's rainbow
Hendi, S. H.; Momennia, M.; Eslam Panah, B.; Panahiyan, S.
2017-06-01
One of the fundamental open questions in cosmology is whether we can regard the universe evolution without singularity like a Big Bang or a Big Rip. This challenging subject stimulates one to regard a nonsingular universe in the far past with an arbitrarily large vacuum energy. Considering the high energy regime in the cosmic history, it is believed that Einstein gravity should be corrected to an effective energy dependent theory which could be acquired by gravity's rainbow. On the other hand, employing massive gravity provided us with solutions to some of the long standing fundamental problems of cosmology such as cosmological constant problem and self acceleration of the universe. Considering these aspects of gravity's rainbow and massive gravity, in this paper, we initiate studying FRW cosmology in the massive gravity's rainbow formalism. At first, we show that although massive gravity modifies the FRW cosmology, but it does not itself remove the big bang singularity. Then, we generalize the massive gravity to the case of energy dependent spacetime and find that massive gravity's rainbow can remove the early universe singularity. We bring together all the essential conditions for having a nonsingular universe and the effects of both gravity's rainbow and massive gravity generalizations on such criteria are determined.
Cosmological attractors in massive gravity
Dubovsky, S; Tkachev, I I
2005-01-01
We study Lorentz-violating models of massive gravity which preserve rotations and are invariant under time-dependent shifts of the spatial coordinates. In the linear approximation the Newtonian potential in these models has an extra ``confining'' term proportional to the distance from the source. We argue that during cosmological expansion the Universe may be driven to an attractor point with larger symmetry which includes particular simultaneous dilatations of time and space coordinates. The confining term in the potential vanishes as one approaches the attractor. In the vicinity of the attractor the extra contribution is present in the Friedmann equation which, in a certain range of parameters, gives rise to the cosmic acceleration.
Quintic quasi-topological gravity
Energy Technology Data Exchange (ETDEWEB)
Cisterna, Adolfo [Vicerrectoría académica, Universidad Central de Chile,Toesca 1783 Santiago (Chile); Instituto de Ciencias Físicas y Matemáticas, Universidad Austral de Chile,Casilla 567, Valdivia (Chile); Guajardo, Luis; Hassaïne, Mokhtar [Instituto de Matemática y Física, Universidad de Talca,Casilla 747, Talca (Chile); Oliva, Julio [Departamento de Física, Universidad de Concepción,Casilla, 160-C, Concepción (Chile)
2017-04-11
We construct a quintic quasi-topological gravity in five dimensions, i.e. a theory with a Lagrangian containing R{sup 5} terms and whose field equations are of second order on spherically (hyperbolic or planar) symmetric spacetimes. These theories have recently received attention since when formulated on asymptotically AdS spacetimes might provide for gravity duals of a broad class of CFTs. For simplicity we focus on five dimensions. We show that this theory fulfils a Birkhoff’s Theorem as it is the case in Lovelock gravity and therefore, for generic values of the couplings, there is no s-wave propagating mode. We prove that the spherically symmetric solution is determined by a quintic algebraic polynomial equation which resembles Wheeler’s polynomial of Lovelock gravity. For the black hole solutions we compute the temperature, mass and entropy and show that the first law of black holes thermodynamics is fulfilled. Besides of being of fourth order in general, we show that the field equations, when linearized around AdS are of second order, and therefore the theory does not propagate ghosts around this background. Besides the class of theories originally introduced in https://arxiv.org/abs/1003.4773, the general geometric structure of these Lagrangians remains an open problem.
Even-dimensional topological gravity from Chern-Simons gravity
International Nuclear Information System (INIS)
Merino, N.; Perez, A.; Salgado, P.
2009-01-01
It is shown that the topological action for gravity in 2n-dimensions can be obtained from the (2n+1)-dimensional Chern-Simons gravity genuinely invariant under the Poincare group. The 2n-dimensional topological gravity is described by the dynamics of the boundary of a (2n+1)-dimensional Chern-Simons gravity theory with suitable boundary conditions. The field φ a , which is necessary to construct this type of topological gravity in even dimensions, is identified with the coset field associated with the non-linear realizations of the Poincare group ISO(d-1,1).
Complexity growth in minimal massive 3D gravity
Qaemmaqami, Mohammad M.
2018-01-01
We study the complexity growth by using "complexity =action " (CA) proposal in the minimal massive 3D gravity (MMG) model which is proposed for resolving the bulk-boundary clash problem of topologically massive gravity (TMG). We observe that the rate of the complexity growth for Banados-Teitelboim-Zanelli (BTZ) black hole saturates the proposed bound by physical mass of the BTZ black hole in the MMG model, when the angular momentum parameter and the inner horizon of black hole goes to zero.
Minimal N=4 topologically massive supergravity
Energy Technology Data Exchange (ETDEWEB)
Kuzenko, Sergei M. [School of Physics M013, The University of Western Australia,35 Stirling Highway, Crawley W.A. 6009 (Australia); Novak, Joseph [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut,Am Mühlenberg 1, D-14476 Golm (Germany); Sachs, Ivo [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität,Theresienstraße 37, D-80333 München (Germany)
2017-03-21
Using the superconformal framework, we construct a new off-shell model for N=4 topologically massive supergravity which is minimal in the sense that it makes use of a single compensating vector multiplet and involves no free parameter. As such, it provides a counterexample to the common lore that two compensating multiplets are required within the conformal approach to supergravity with eight supercharges in diverse dimensions. This theory is an off-shell N=4 supersymmetric extension of chiral gravity. All of its solutions correspond to non-conformally flat superspaces. Its maximally supersymmetric solutions include the so-called critical (4,0) anti-de Sitter superspace introduced in https://www.doi.org/10.1007/JHEP08(2012)024, and well as warped critical (4,0) anti-de Sitter superspaces. We also propose a dual formulation for the theory in which the vector multiplet is replaced with an off-shell hypermultiplet. Upon elimination of the auxiliary fields belonging to the hypermultiplet and imposing certain gauge conditions, the dual action reduces to the one introduced in https://www.doi.org/10.1103/PhysRevD.94.065028.
Algebraic definition of topological W gravity
International Nuclear Information System (INIS)
Hosono, S.
1992-01-01
In this paper, the authors propose a definition of the topological W gravity using some properties of the principal three-dimensional subalgebra of a simple Lie algebra due to Kostant. In the authors' definition, structures of the two-dimensional topological gravity are naturally embedded in the extended theories. In accordance with the definition, the authors will present some explicit calculations for the W 3 gravity
Massive gravity and Fierz-Pauli theory
International Nuclear Information System (INIS)
Blasi, Alberto; Maggiore, Nicola
2017-01-01
Linearized gravity is considered as an ordinary gauge field theory. This implies the need for gauge fixing in order to have well-defined propagators. Only after having achieved this, the most general mass term is added. The aim of this paper is to study of the degrees of freedom of the gauge fixed theory of linearized gravity with mass term. The main result is that, even outside the usual Fierz-Pauli constraint on the mass term, it is possible to choose a gauge fixing belonging to the Landau class, which leads to a massive theory of gravity with the five degrees of freedom of a spin-2 massive particle. (orig.)
Massive gravity and Fierz-Pauli theory
Energy Technology Data Exchange (ETDEWEB)
Blasi, Alberto [Universita di Genova, Dipartimento di Fisica, Genova (Italy); Maggiore, Nicola [I.N.F.N.-Sezione di Genova, Genoa (Italy)
2017-09-15
Linearized gravity is considered as an ordinary gauge field theory. This implies the need for gauge fixing in order to have well-defined propagators. Only after having achieved this, the most general mass term is added. The aim of this paper is to study of the degrees of freedom of the gauge fixed theory of linearized gravity with mass term. The main result is that, even outside the usual Fierz-Pauli constraint on the mass term, it is possible to choose a gauge fixing belonging to the Landau class, which leads to a massive theory of gravity with the five degrees of freedom of a spin-2 massive particle. (orig.)
Comment on ''Topologically Massive Gauge Theories''
International Nuclear Information System (INIS)
Bezerra de Mello, E.R.
1988-01-01
In a recent paper by R. Pisarski and S. Rao concerning topologically massive quantum Yang--Mills theory, the expression of the P-even part of the non-Abelian gauge field self-energy at one-loop order is shown to obey a consistency condition, which is not fulfilled by the formula originally presented by S. Deser, R. Jackiw, and S. Templeton. In this comment, I present a recalculation which agress with Pisarski and Rao. copyright 1988 Academic Press, Inc
Alishahiha, Mohsen; Naseh, Ali; Shirzad, Ahmad
2014-12-03
We study linearized equations of motion of the newly proposed three dimensional gravity, known as minimal massive gravity, using its metric formulation. We observe that the resultant linearized equations are exactly the same as that of TMG by making use of a redefinition of the parameters of the model. In particular the model admits logarithmic modes at the critical points. We also study several vacuum solutions of the model, specially at a certain limit where the contribution of Chern-Simons term vanishes.
Proceeding of the workshop on quantum gravity and topology
International Nuclear Information System (INIS)
Oda, Ichiro
1991-10-01
The workshop on Quantum Gravity and Topology was held at INS on February 21-23, 1991. Several introductory lectures and more than 15 talks were delivered for about 100 participants. The main subjects discussed were i) Topological quantum field theories and topological gravity ii) Low dimensional and four dimensional gravity iii) Topology change iv) Superstring theories etc. (J.P.N.)
Gapless topological order, gravity, and black holes
Rasmussen, Alex; Jermyn, Adam S.
2018-04-01
In this work we demonstrate that linearized gravity exhibits gapless topological order with an extensive ground state degeneracy. This phenomenon is closely related both to the topological order of the pyrochlore U (1 ) spin liquid and to recent work by Hawking and co-workers, who used the soft-photon and graviton theorems to demonstrate that the vacuum in linearized gravity is not unique. We first consider lattice models whose low-energy behavior is described by electromagnetism and linearized gravity, and then argue that the topological nature of these models carries over into the continuum. We demonstrate that these models can have many ground states without making assumptions about the topology of spacetime or about the high-energy nature of the theory, and show that the infinite family of symmetries described by Hawking and co-workers is simply the different topological sectors. We argue that in this context black holes appear as topological defects in the infrared theory, and that this suggests a potential approach to understanding both the firewall paradox and information encoding in gravitational theories. Finally, we use insights from the soft-boson theorems to make connections between deconfined gauge theories with continuous gauge groups and gapless topological order.
Emergent universe with wormholes in massive gravity
Paul, B. C.; Majumdar, A. S.
2018-03-01
An emergent universe (EU) scenario is proposed to obtain a universe free from big-bang singularity. In this framework the present universe emerged from a static Einstein universe phase in the infinite past. A flat EU scenario is found to exist in Einstein’s gravity with a non-linear equation of state (EoS). It has been shown subsequently that a physically realistic EU model can be obtained considering cosmic fluid composed of interacting fluids with a non-linear equation of state. It results a viable cosmological model accommodating both early inflation and present accelerating phases. In the present paper, the origin of an initial static Einstein universe needed in the EU model is explored in a massive gravity theory which subsequently emerged to be a dynamically evolving universe. A new gravitational instanton solution in a flat universe is obtained in the massive gravity theory which is a dynamical wormhole that might play an important role in realizing the origin of the initial state of the emergent universe. The emergence of a Lorentzian universe from a Euclidean gravity is understood by a Wick rotation τ = i t . A universe with radiation at the beginning finally transits into the present observed universe with a non-linear EoS as the interactions among the fluids set in. Thus a viable flat EU scenario where the universe stretches back into time infinitely, with no big bang is permitted in a massive gravity.
Monopole Solutions in Topologically Massive Gauge Theory
International Nuclear Information System (INIS)
Teh, Rosy; Wong, Khai-Ming; Koh, Pin-Wai
2010-01-01
Monopoles in topologically massive SU(2) Yang-Mils-Higgs gauge theory in 2+1 dimensions with a Chern-Simon mass term have been studied by Pisarski some years ago. He argued that there is a monopole solution that is regular everywhere, but found that it does not possess finite action. There were no exact or numerical solutions being presented by him. Hence it is our purpose to further investigate this solution in more detail. We obtained numerical regular solutions that smoothly interpolates between the behavior at small and large distances for different values of Chern-Simon term strength and for several fixed values of Higgs field strength.
Cutoff for extensions of massive gravity and bi-gravity
International Nuclear Information System (INIS)
Matas, Andrew
2016-01-01
Recently there has been interest in extending ghost-free massive gravity, bi-gravity, and multi-gravity by including non-standard kinetic terms and matter couplings. We first review recent proposals for this class of extensions, emphasizing how modifications of the kinetic and potential structure of the graviton and modifications of the coupling to matter are related. We then generalize existing no-go arguments in the metric language to the vielbein language in second-order form. We give an ADM argument to show that the most promising extensions to the kinetic term and matter coupling contain a Boulware–Deser ghost. However, as recently emphasized, we may still be able to view these extensions as effective field theories below some cutoff scale. To address this possibility, we show that there is a decoupling limit where a ghost appears for a wide class of matter couplings and kinetic terms. In particular, we show that there is a decoupling limit where the linear effective vielbein matter coupling contains a ghost. Using the insight we gain from this decoupling limit analysis, we place an upper bound on the cutoff for the linear effective vielbein coupling. This result can be generalized to new kinetic interactions in the vielbein language in second-order form. Combined with recent results, this provides a strong uniqueness argument on the form of ghost-free massive gravity, bi-gravity, and multi-gravity. (paper)
On the spontaneous breakdown of massive gravities in 2 + 1 dimension
International Nuclear Information System (INIS)
Aragone, C.; Aria, P.J.; Andes Merida, Univ.; Khoudeir, A.
1997-01-01
This paper shows that locally Lorentz-invariant, third-order, topological massive gravity cannot be broken down either to the local diffeomorphism subgroup or to the rigid Poincare' group. On the other hand, the recently formulated, locally diffeomorphism-invariant, second order massive tradic (translational) Chern-Simons gravity breaks down on rigid Minkowski space to a double massive spin-two system. This flat double massive action is the uniform spin-two generalization of the Maxwell-Chern-Simons-Proca system which one is left with after U(1) Abelian gauge invariance breaks down in the presence of a sextic Higgs potential
Cosmology in general massive gravity theories
International Nuclear Information System (INIS)
Comelli, D.; Nesti, F.; Pilo, L.
2014-01-01
We study the cosmological FRW flat solutions generated in general massive gravity theories. Such a model are obtained adding to the Einstein General Relativity action a peculiar non derivative potentials, function of the metric components, that induce the propagation of five gravitational degrees of freedom. This large class of theories includes both the case with a residual Lorentz invariance as well as the case with rotational invariance only. It turns out that the Lorentz-breaking case is selected as the only possibility. Moreover it turns out that that perturbations around strict Minkowski or dS space are strongly coupled. The upshot is that even though dark energy can be simply accounted by massive gravity modifications, its equation of state w eff has to deviate from -1. Indeed, there is an explicit relation between the strong coupling scale of perturbations and the deviation of w eff from -1. Taking into account current limits on w eff and submillimiter tests of the Newton's law as a limit on the possible strong coupling scale, we find that it is still possible to have a weakly coupled theory in a quasi dS background. Future experimental improvements on short distance tests of the Newton's law may be used to tighten the deviation of w eff form -1 in a weakly coupled massive gravity theory
Topology and dark energy: testing gravity in voids.
Spolyar, Douglas; Sahlén, Martin; Silk, Joe
2013-12-13
Modified gravity has garnered interest as a backstop against dark matter and dark energy (DE). As one possible modification, the graviton can become massive, which introduces a new scalar field--here with a Galileon-type symmetry. The field can lead to a nontrivial equation of state of DE which is density and scale dependent. Tension between type Ia supernovae and Planck could be reduced. In voids, the scalar field dramatically alters the equation of state of DE, induces a soon-observable gravitational slip between the two metric potentials, and develops a topological defect (domain wall) due to a nontrivial vacuum structure for the field.
The Black Hole Radiation in Massive Gravity
Directory of Open Access Journals (Sweden)
Ivan Arraut
2018-02-01
Full Text Available We apply the Bogoliubov transformations in order to connect two different vacuums, one located at past infinity and another located at future infinity around a black hole inside the scenario of the nonlinear theory of massive gravity. The presence of the extra degrees of freedom changes the behavior of the logarithmic singularity and, as a consequence, the relation between the two Bogoliubov coefficients. This has an effect on the number of particles, or equivalently, on the black hole temperature perceived by observers defining the time arbitrarily.
Complexity growth rates for AdS black holes in massive gravity and f(R) gravity
Energy Technology Data Exchange (ETDEWEB)
Guo, Wen-Di; Wei, Shao-Wen; Li, Yan-Yan; Liu, Yu-Xiao [Lanzhou University, Institute of Theoretical Physics, Lanzhou (China)
2017-12-15
The ''complexity = action'' duality states that the quantum complexity is equal to the action of the stationary AdS black hole within the Wheeler-DeWitt patch at late time approximation. We compute the action growth rates of the neutral and charged black holes in massive gravity and the neutral, charged and Kerr-Newman black holes in f(R) gravity to test this conjecture. Besides, we investigate the effects of the massive graviton terms, higher derivative terms and the topology of the black hole horizon on the complexity growth rate. (orig.)
On physical states in 2d (topological) gravity
International Nuclear Information System (INIS)
Bouwknegt, P.; McCarthy, J.; Pilch, K.
1993-01-01
We review the BRST computation of physical states in various 2d gravity theories. First we discuss the cohomology relevant for 2d gravity coupled to c ≤ 1 conformal matter. We then use these results to compute the cohomology of a c=26 βγ-system, i.e. restricted 2d topological gravity. We also comment on the cohomology for the complete 2d topological gravity. (author). 39 refs
Holographic heat engine within the framework of massive gravity
Mo, Jie-Xiong; Li, Gu-Qiang
2018-05-01
Heat engine models are constructed within the framework of massive gravity in this paper. For the four-dimensional charged black holes in massive gravity, it is shown that the existence of graviton mass improves the heat engine efficiency significantly. The situation is more complicated for the five-dimensional neutral black holes since the constant which corresponds to the third massive potential also contributes to the efficiency. It is also shown that the existence of graviton mass can improve the heat engine efficiency. Moreover, we probe how the massive gravity influences the behavior of the heat engine efficiency approaching the Carnot efficiency.
Neutron stars structure in the context of massive gravity
Energy Technology Data Exchange (ETDEWEB)
Hendi, S.H.; Bordbar, G.H.; Panah, B. Eslam; Panahiyan, S., E-mail: hendi@shirazu.ac.ir, E-mail: ghbordbar@shirazu.ac.ir, E-mail: behzad.eslampanah@gmail.com, E-mail: sh.panahiyan@gmail.com [Physics Department and Biruni Observatory, College of Sciences, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)
2017-07-01
Motivated by the recent interests in spin−2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.
Neutron stars structure in the context of massive gravity
Hendi, S. H.; Bordbar, G. H.; Eslam Panah, B.; Panahiyan, S.
2017-07-01
Motivated by the recent interests in spin-2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.
Neutron stars structure in the context of massive gravity
International Nuclear Information System (INIS)
Hendi, S.H.; Bordbar, G.H.; Panah, B. Eslam; Panahiyan, S.
2017-01-01
Motivated by the recent interests in spin−2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.
Topological gravity from a transgression gauge field theory
International Nuclear Information System (INIS)
Merino, N.; Perez, A.; Salgado, P.; Valdivia, O.
2010-01-01
It is shown that a topological action for gravity in even dimensions can be obtained from a gravity theory whose Lagrangian is given by a transgression form invariant under the Poincare group. The field φ a , which is necessary to construct this type of topological gravity in even dimensions, is identified with the coset field associated with the non-linear realizations of the Poincare group ISO(d-1,1).
Massive gravity with mass term in three dimensions
International Nuclear Information System (INIS)
Nakasone, Masashi; Oda, Ichiro
2009-01-01
We analyze the effect of the Pauli-Fierz mass term on a recently established, new massive gravity theory in three space-time dimensions. We show that the Pauli-Fierz mass term makes the new massive gravity theory nonunitary. Moreover, although we add the gravitational Chern-Simons term to this model, the situation remains unchanged and the theory stays nonunitary despite that the structure of the graviton propagator is greatly changed. Thus, the Pauli-Fierz mass term is not allowed to coexist with mass-generating higher-derivative terms in the new massive gravity.
A geometric view on topologically massive gauge theories
International Nuclear Information System (INIS)
Horvathy, P.A.; Nash, C.
1985-01-01
The topologically massive gauge theory of Deser, Jackiw and Templeton is understood from Souriau's Principle of General Covariance. The non-gauge invariant mass term corresponds to a non-trivial class in the first cohomology group of configuration space, generated by the Chern-Simons secondary characteristic class. Quantization requires this class to be integral
A spin-4 analog of 3D massive gravity
Bergshoeff, Eric A.; Kovacevic, Marija; Rosseel, Jan; Townsend, Paul K.; Yin, Yihao
2011-01-01
A sixth-order, but ghost-free, gauge-invariant action is found for a fourth-rank symmetric tensor potential in a three-dimensional (3D) Minkowski spacetime. It propagates two massive modes of spin 4 that are interchanged by parity and is thus a spin-4 analog of linearized 'new massive gravity'. Also
Topological Gravity on $(D,N)-$Shift Superspace Formulation
Lourenco, José A.; Neto, José A. Helayël; Spalenza, Wesley
2017-01-01
In this contribution, we re-assess the subject of topological gravity by following the Shift Supersymmetry formalism. The gauge-fixing of the theory goes under the Batallin-Vilkovisky (BV) prescription based on a diagram that contains both ghost and anti-ghost superfields, associated to the super-vielbein and the super-Lorentz connection. We extend the formulation of the topological gravity action to an arbitrary number of dimensions of the shift superspace by adopting a formulation based on ...
Cosmological stability bound in massive gravity and bigravity
International Nuclear Information System (INIS)
Fasiello, Matteo; Tolley, Andrew J.
2013-01-01
We give a simple derivation of a cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an FRW reference metric and for bigravity theories. This bound comes from the requirement that the kinetic term of the helicity zero mode of the graviton is positive definite. The bound is dependent only on the parameters in the massive gravity potential and the Hubble expansion rate for the two metrics. We derive the decoupling limit of bigravity and FRW massive gravity, and use this to give an independent derivation of the cosmological bound. We recover our previous results that the tension between satisfying the Friedmann equation and the cosmological bound is sufficient to rule out all observationally relevant FRW solutions for massive gravity with an FRW reference metric. In contrast, in bigravity this tension is resolved due to different nature of the Vainshtein mechanism. We find that in bigravity theories there exists an FRW solution with late-time self-acceleration for which the kinetic terms for the helicity-2, helicity-1 and helicity-0 are generically nonzero and positive making this a compelling candidate for a model of cosmic acceleration. We confirm that the generalized bound is saturated for the candidate partially massless (bi)gravity theories but the existence of helicity-1/helicity-0 interactions implies the absence of the conjectured partially massless symmetry for both massive gravity and bigravity
Conserved charges of minimal massive gravity coupled to scalar field
Setare, M. R.; Adami, H.
2018-02-01
Recently, the theory of topologically massive gravity non-minimally coupled to a scalar field has been proposed, which comes from the Lorentz-Chern-Simons theory (JHEP 06, 113, 2015), a torsion-free theory. We extend this theory by adding an extra term which makes the torsion to be non-zero. We show that the BTZ spacetime is a particular solution to this theory in the case where the scalar field is constant. The quasi-local conserved charge is defined by the concept of the generalized off-shell ADT current. Also a general formula is found for the entropy of the stationary black hole solution in context of the considered theory. The obtained formulas are applied to the BTZ black hole solution in order to obtain the energy, the angular momentum and the entropy of this solution. The central extension term, the central charges and the eigenvalues of the Virasoro algebra generators for the BTZ black hole solution are thus obtained. The energy and the angular momentum of the BTZ black hole using the eigenvalues of the Virasoro algebra generators are calculated. Also, using the Cardy formula, the entropy of the BTZ black hole is found. It is found that the results obtained in two different ways exactly match, just as expected.
Conserved charges of minimal massive gravity coupled to scalar field
International Nuclear Information System (INIS)
Setare, M.R.; Adami, H.
2018-01-01
Recently, the theory of topologically massive gravity non-minimally coupled to a scalar field has been proposed, which comes from the Lorentz-Chern-Simons theory (JHEP 06, 113, 2015), a torsion-free theory. We extend this theory by adding an extra term which makes the torsion to be non-zero. We show that the BTZ spacetime is a particular solution to this theory in the case where the scalar field is constant. The quasi-local conserved charge is defined by the concept of the generalized off-shell ADT current. Also a general formula is found for the entropy of the stationary black hole solution in context of the considered theory. The obtained formulas are applied to the BTZ black hole solution in order to obtain the energy, the angular momentum and the entropy of this solution. The central extension term, the central charges and the eigenvalues of the Virasoro algebra generators for the BTZ black hole solution are thus obtained. The energy and the angular momentum of the BTZ black hole using the eigenvalues of the Virasoro algebra generators are calculated. Also, using the Cardy formula, the entropy of the BTZ black hole is found. It is found that the results obtained in two different ways exactly match, just as expected. (orig.)
Conserved charges of minimal massive gravity coupled to scalar field
Energy Technology Data Exchange (ETDEWEB)
Setare, M.R.; Adami, H. [University of Kurdistan, Department of Science, Sanandaj (Iran, Islamic Republic of)
2018-02-15
Recently, the theory of topologically massive gravity non-minimally coupled to a scalar field has been proposed, which comes from the Lorentz-Chern-Simons theory (JHEP 06, 113, 2015), a torsion-free theory. We extend this theory by adding an extra term which makes the torsion to be non-zero. We show that the BTZ spacetime is a particular solution to this theory in the case where the scalar field is constant. The quasi-local conserved charge is defined by the concept of the generalized off-shell ADT current. Also a general formula is found for the entropy of the stationary black hole solution in context of the considered theory. The obtained formulas are applied to the BTZ black hole solution in order to obtain the energy, the angular momentum and the entropy of this solution. The central extension term, the central charges and the eigenvalues of the Virasoro algebra generators for the BTZ black hole solution are thus obtained. The energy and the angular momentum of the BTZ black hole using the eigenvalues of the Virasoro algebra generators are calculated. Also, using the Cardy formula, the entropy of the BTZ black hole is found. It is found that the results obtained in two different ways exactly match, just as expected. (orig.)
Once more about the topologically massive gauge theory
International Nuclear Information System (INIS)
Kogan, Ya.I.
1989-01-01
The general properties of the three-dimensional gauge theory with the topological mass is discussed namely the long-range interaction of the Aharonov-Bohm type. It is argued that Chern-Simons gauge theories must be considered as the infrared limit of the topologically massive theories. The analogy between the Landau problem of a charged particle in a magnetic field and quantization of this gauge theory is considered, as well as the quantization condition for the Abelian Chern-Simons term. 38 refs.; 5 figs
Massive gravity wrapped in the cosmic web
International Nuclear Information System (INIS)
Shim, Junsup; Lee, Jounghun; Li, Baojiu
2014-01-01
We study how the filamentary pattern of the cosmic web changes if the true gravity deviates from general relativity (GR) on a large scale. The f(R) gravity, whose strength is controlled to satisfy the current observational constraints on the cluster scale, is adopted as our fiducial model and a large, high-resolution N-body simulation is utilized for this study. By applying the minimal spanning tree algorithm to the halo catalogs from the simulation at various epochs, we identify the main stems of the rich superclusters located in the most prominent filamentary section of the cosmic web and determine their spatial extents per member cluster to be the degree of their straightness. It is found that the f(R) gravity has the effect of significantly bending the superclusters and that the effect becomes stronger as the universe evolves. Even in the case where the deviation from GR is too small to be detectable by any other observables, the degree of the supercluster straightness exhibits a conspicuous difference between the f(R) and the GR models. Our results also imply that the supercluster straightness could be a useful discriminator of f(R) gravity from the coupled dark energy since it is shown to evolve differently between the two models. As a final conclusion, the degree of the straightness of the rich superclusters should provide a powerful cosmological test of large scale gravity.
Massive gravity wrapped in the cosmic web
Energy Technology Data Exchange (ETDEWEB)
Shim, Junsup; Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Li, Baojiu, E-mail: jsshim@astro.snu.ac.kr, E-mail: jounghun@astro.snu.ac.kr [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)
2014-03-20
We study how the filamentary pattern of the cosmic web changes if the true gravity deviates from general relativity (GR) on a large scale. The f(R) gravity, whose strength is controlled to satisfy the current observational constraints on the cluster scale, is adopted as our fiducial model and a large, high-resolution N-body simulation is utilized for this study. By applying the minimal spanning tree algorithm to the halo catalogs from the simulation at various epochs, we identify the main stems of the rich superclusters located in the most prominent filamentary section of the cosmic web and determine their spatial extents per member cluster to be the degree of their straightness. It is found that the f(R) gravity has the effect of significantly bending the superclusters and that the effect becomes stronger as the universe evolves. Even in the case where the deviation from GR is too small to be detectable by any other observables, the degree of the supercluster straightness exhibits a conspicuous difference between the f(R) and the GR models. Our results also imply that the supercluster straightness could be a useful discriminator of f(R) gravity from the coupled dark energy since it is shown to evolve differently between the two models. As a final conclusion, the degree of the straightness of the rich superclusters should provide a powerful cosmological test of large scale gravity.
Three-dimensional massive gravity and the bigravity black hole
International Nuclear Information System (INIS)
Banados, Maximo; Theisen, Stefan
2009-01-01
We study three-dimensional massive gravity formulated as a theory with two dynamical metrics, like the f-g theories of Isham-Salam and Strathdee. The action is parity preserving and has no higher derivative terms. The spectrum contains a single massive graviton. This theory has several features discussed recently in TMG and NMG. We find warped black holes, a critical point, and generalized Brown-Henneaux boundary conditions.
Quark–hadron phase transition in massive gravity
Energy Technology Data Exchange (ETDEWEB)
Atazadeh, K., E-mail: atazadeh@azaruniv.ac.ir
2016-11-15
We study the quark–hadron phase transition in the framework of massive gravity. We show that the modification of the FRW cosmological equations leads to the quark–hadron phase transition in the early massive Universe. Using numerical analysis, we consider that a phase transition based on the chiral symmetry breaking after the electroweak transition, occurred at approximately 10 μs after the Big Bang to convert a plasma of free quarks and gluons into hadrons.
From Lorentz-Chern-Simons to Massive Gravity in 2+1 dimensions
Energy Technology Data Exchange (ETDEWEB)
Pino, Simón del [Instituto de Física, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso,Av. Universidad 330, Curauma, Valparaíso (Chile); Giribet, Gaston [Physique Théorique et Mathématique, Université Libre de Bruxelles andInternational Solvay Institutes,Campus Plaine C.P. 231, Bruxelles, B-1050 (Belgium); Departamento de Física, Universidad de Buenos Aires and IFIBA-CONICET,Ciudad Universitaria, Pabellón I, Buenos Aires, 1428 (Argentina); Instituto de Física, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso,Av. Universidad 330, Curauma, Valparaíso (Chile); Toloza, Adolfo [Instituto de Física, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso,Av. Universidad 330, Curauma, Valparaíso (Chile); Centro de Estudios Científicos CECs,Arturo Prat 514, Valdivia (Chile); Zanelli, Jorge [Centro de Estudios Científicos CECs,Arturo Prat 514, Valdivia (Chile)
2015-06-17
We propose a generalization of Chiral Gravity, which follows from considering a Chern-Simons action for the spin connection with anti-symmetric contorsion. The theory corresponds to Topologically Massive Gravity at the chiral point non-minimally coupled to an additional scalar mode that gathers the torsion degree of freedom. In this setup, the effective cosmological constant (the inverse of the curvature radius of maximally symmetric solutions) is either negative or zero, and it enters as an integration constant associated to the value of the contorsion at infinity. We explain how this is not in conflict with the Zamolodchikov’s c-theorem holding in the dual boundary theory. In fact, we conjecture that the theory formulated about three-dimensional Anti-de Sitter space is dual to a two-dimensional conformal field theory whose right- and left-moving central charges are given by c{sub R}=24k and c{sub L}=0, respectively, being k the level of the Chern-Simons action. We study the classical theory both at the linear and non-linear level. In particular, we show how Chiral Gravity is included as a special sector. In addition, the theory has other sectors, which we explore; we exhibit analytic exact solutions that are not solutions of Topologically Massive Gravity (and, consequently, neither of General Relativity) and still satisfy Brown-Henneaux asymptotically AdS{sub 3} boundary conditions.
Complexity growth in massive gravity theories, the effects of chirality, and more
Ghodrati, Mahdis
2017-11-01
To study the effect of parity violation on the rate of complexity growth, by using "complexity=action " conjecture, we find the complexity growth rates in different solutions of the chiral theory of topologically massive gravity (TMG) and parity-preserving theory of new massive gravity (NMG). Using the results, one can see that decreasing the parameter μ , which increases the effect of the Chern-Simons term and increases chirality, would increase the rate of growth of complexity. Also one can observe a stronger correlation between complexity growth and temperature rather than complexity growth and entropy. At the end we comment on the possible meaning of the deforming term of chiral Liouville action for the rate of complexity growth of warped conformal field theories in the tensor network renormalization picture.
Generalized massive gravity in arbitrary dimensions and its Hamiltonian formulation
International Nuclear Information System (INIS)
Huang, Qing-Guo; Zhang, Ke-Chao; Zhou, Shuang-Yong
2013-01-01
We extend the four-dimensional de Rham-Gabadadze-Tolley (dRGT) massive gravity model to a general scalar massive-tensor theory in arbitrary dimensions, coupling a dRGT massive graviton to multiple scalars and allowing for generic kinetic and mass matrix mixing between the massive graviton and the scalars, and derive its Hamiltonian formulation and associated constraint system. When passing to the Hamiltonian formulation, two different sectors arise: a general sector and a special sector. Although obtained via different ways, there are two second class constraints in either of the two sectors, eliminating the BD ghost. However, for the special sector, there are still ghost instabilities except for the case of two dimensions. In particular, for the special sector with one scalar, there is a ''second BD ghost''
Black holes in quasi-topological gravity and conformal couplings
Chernicoff, Mariano; Fierro, Octavio; Giribet, Gaston; Oliva, Julio
2017-02-01
Lovelock theory of gravity provides a tractable model to investigate the effects of higher-curvature terms in the context of AdS/CFT. Yielding second order, ghost-free field equations, this theory represents a minimal setup in which higher-order gravitational couplings in asymptotically Anti-de Sitter (AdS) spaces, including black holes, can be solved analytically. This however has an obvious limitation as in dimensions lower than seven, the contribution from cubic or higher curvature terms is merely topological. Therefore, in order to go beyond quadratic order and study higher terms in AdS5 analytically, one is compelled to look for other toy models. One such model is the so-called quasi-topological gravity, which, despite being a higher-derivative theory, provides a tractable setup with R 3 and R 4 terms. In this paper, we investigate AdS5 black holes in quasi-topological gravity. We consider the theory conformally coupled to matter and in presence of Abelian gauge fields. We show that charged black holes in AdS5 which, in addition, exhibit a backreaction of the matter fields on the geometry can be found explicitly in this theory. These solutions generalize the black hole solution of quasi-topological gravity and exist in a region of the parameter spaces consistent with the constraints coming from causality and other consistency conditions. They have finite conserved charges and exhibit non-trivial thermodynamical properties.
Black holes in quasi-topological gravity and conformal couplings
International Nuclear Information System (INIS)
Chernicoff, Mariano; Fierro, Octavio; Giribet, Gaston; Oliva, Julio
2017-01-01
Lovelock theory of gravity provides a tractable model to investigate the effects of higher-curvature terms in the context of AdS/CFT. Yielding second order, ghost-free field equations, this theory represents a minimal setup in which higher-order gravitational couplings in asymptotically Anti-de Sitter (AdS) spaces, including black holes, can be solved analytically. This however has an obvious limitation as in dimensions lower than seven, the contribution from cubic or higher curvature terms is merely topological. Therefore, in order to go beyond quadratic order and study higher terms in AdS 5 analytically, one is compelled to look for other toy models. One such model is the so-called quasi-topological gravity, which, despite being a higher-derivative theory, provides a tractable setup with R 3 and R 4 terms. In this paper, we investigate AdS 5 black holes in quasi-topological gravity. We consider the theory conformally coupled to matter and in presence of Abelian gauge fields. We show that charged black holes in AdS 5 which, in addition, exhibit a backreaction of the matter fields on the geometry can be found explicitly in this theory. These solutions generalize the black hole solution of quasi-topological gravity and exist in a region of the parameter spaces consistent with the constraints coming from causality and other consistency conditions. They have finite conserved charges and exhibit non-trivial thermodynamical properties.
Unruly topologies in two-dimensional quantum gravity
International Nuclear Information System (INIS)
Hartle, J.B.
1985-01-01
A sum over histories formulation of quantum geometry could involve sums over different topologies as well as sums over different metrics. In classical gravity a geometry is a manifold with a metric, but it is difficult to implement a sum over manifolds in quantum gravity. In this difficulty, motivation is found for including in the sum over histories, geometries defined on more general objects than manifolds-unruly topologies. In simplicial two-dimensional quantum gravity a class of simplicial complexes is found to which the gravitational action can be extended, for which sums over the class are straightforwardly defined, and for which a manifold dominates the sum in the classical limit. The situation in higher dimensions is discussed. (author)
Holographic RG flows from Quasi-Topological Gravity
International Nuclear Information System (INIS)
Camara da Silva, U.; Sotkov, G.M.
2013-01-01
We investigate the holographic Renormalization Group (RG) flows and the critical phenomena that take place in the QFT's dual to the d-dimensional cubic Quasi-Topological Gravity coupled to scalar matter. The knowledge of the corresponding flat Domain Walls (DW's) solutions allows us to derive the explicit form of the QFT's β-functions, as well as of the trace anomalies a(l) and c(l), in terms of the matter superpotential. As a consequence we are able to determine the complete set of CFT data characterizing the universality classes of the UV and IR critical points and to follow the particular RG evolution of this data. We further analyse the dependence of the critical properties of such dual QFT's on the values of the Lovelock couplings and on the shape of the superpotential. For odd values of d, the explicit form of the “a and c-central charges” as functions of the running coupling constant, enable us to establish the conditions under which the a and c-Theorems for their decreasing are valid. The restrictions imposed on the massless holographic RG flows by the requirements of the positivity of the energy fluxes are derived. The particular case of quartic Higgs-like superpotential is studied in detail. It provides an example of unitary dual QFT's having few c≠a-critical points representing second or infinite order phase transitions. Depending on the range of the values of the coupling constant they exhibit massive and massless phases, described by a chain of distinct DW's solutions sharing common boundaries
No hair theorem in quasi-dilaton massive gravity
Energy Technology Data Exchange (ETDEWEB)
Wu, De-Jun, E-mail: wudejun10@mails.ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhou, Shuang-Yong, E-mail: sxz353@case.edu [Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106 (United States)
2016-06-10
We investigate the static, spherically symmetric black hole solutions in the quasi-dilaton model and its generalizations, which are scalar extended dRGT massive gravity with a shift symmetry. We show that, unlike generic scalar extended massive gravity models, these theories do not admit static, spherically symmetric black hole solutions until the theory parameters in the dRGT potential are fine-tuned. When fine-tuned, the geometry of the static, spherically symmetric black hole is necessarily that of general relativity and the quasi-dilaton field is constant across the spacetime. The fine-tuning and the no hair theorem apply to black holes with flat, anti-de Sitter or de Sitter asymptotics.
No hair theorem in quasi-dilaton massive gravity
International Nuclear Information System (INIS)
Wu, De-Jun; Zhou, Shuang-Yong
2016-01-01
We investigate the static, spherically symmetric black hole solutions in the quasi-dilaton model and its generalizations, which are scalar extended dRGT massive gravity with a shift symmetry. We show that, unlike generic scalar extended massive gravity models, these theories do not admit static, spherically symmetric black hole solutions until the theory parameters in the dRGT potential are fine-tuned. When fine-tuned, the geometry of the static, spherically symmetric black hole is necessarily that of general relativity and the quasi-dilaton field is constant across the spacetime. The fine-tuning and the no hair theorem apply to black holes with flat, anti-de Sitter or de Sitter asymptotics.
Interplay between topology, gauge fields and gravity
Corichi Rodriguez Gil, Alejandro
In this thesis we consider several physical systems that illustrate an interesting interplay between quantum theory, connections and knot theory. It can be divided into two parts. In the first one, we consider the quantization of the free Maxwell field. We show that there is an important role played by knot theory, and in particular the Gauss linking number, in the quantum theory. This manifestation is twofold. The first occurs at the level of the algebra of observables given by fluxes of electric and magnetic field across surfaces. The commutator of the operators, and thus the basic uncertainty relations, are given in terms of the linking number of the loops that bound the surfaces. Next, we consider the quantization of the Maxwell field based on self-dual connections in the loop representation. We show that the measure which determines the quantum inner product can be expressed in terms of the self linking number of thickened loops. Therefore, the linking number manifests itself at two key points of the theory: the Heisenberg uncertainty principle and the inner product. In the second part, we bring gravity into play. First we consider quantum test particles on certain stationary space-times. We demonstrate that a geometric phase exists for those space-times and focus on the example of a rotating cosmic string. The geometric phase can be explicitly computed, providing a fully relativistic gravitational Aharonov-Bohm effect. Finally, we consider 3-dimensional gravity with non-vanishing cosmological constant in the connection dynamics formulation. We restrict our attention to Lorentzian gravity with positive cosmological constant and Euclidean signature with negative cosmological constant. A complex transformation is performed in phase space that makes the constraints simple. The reduced phase space is characterized as the moduli space of flat complex connections. We construct the quantization of the theory when the initial hyper-surface is a torus. Two important
New Massive Gravity and AdS4 Counterterms
International Nuclear Information System (INIS)
Jatkar, Dileep P.; Sinha, Aninda
2011-01-01
We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS 4 ). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS 4 Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS 3 gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory.
Supersymmetric warped AdS in extended topologically massive supergravity
International Nuclear Information System (INIS)
Deger, N.S.; Kaya, A.; Samtleben, H.; Sezgin, E.
2014-01-01
We determine the most general form of off-shell N=(1,1) supergravity field configurations in three dimensions by requiring that at least one off-shell Killing spinor exists. We then impose the field equations of the topologically massive off-shell supergravity and find a class of solutions whose properties crucially depend on the norm of the auxiliary vector field. These are spacelike-squashed and timelike-stretched AdS 3 for the spacelike and timelike norms, respectively. At the transition point where the norm vanishes, the solution is null warped AdS 3 . This occurs when the coefficient of the Lorentz–Chern–Simons term is related to the AdS radius by μℓ=2. We find that the spacelike-squashed AdS 3 can be modded out by a suitable discrete subgroup of the isometry group, yielding an extremal black hole solution which avoids closed timelike curves
The general supersymmetric solution of topologically massive supergravity
International Nuclear Information System (INIS)
Gibbons, G W; Pope, C N; Sezgin, E
2008-01-01
We find the general fully nonlinear solution of topologically massive supergravity admitting a Killing spinor. It is of plane-wave type, with a null Killing vector field. Conversely, we show that all solutions with a null Killing vector are supersymmetric for one or the other choice of sign for the Chern-Simons coupling constant μ. If μ does not take the critical value, μ = ±1, these solutions are asymptotically regular on a Poincare patch, but do not admit a smooth global compactification with boundary S 1 x R. In the critical case, the solutions have a logarithmic singularity on the boundary of the Poincare patch. We derive a Nester-Witten identity, which allows us to identify the associated charges, but we conclude that the presence of the Chern-Simons term prevents us from making a statement about their positivity. The Nester-Witten procedure is applied to the BTZ black hole
Zwei-Dreibein Gravity : A Two-Frame-Field Model of 3D Massive Gravity
Bergshoeff, Eric A.; de Haan, Sjoerd; Hohm, Olaf; Merbis, Wout; Townsend, Paul K.
2013-01-01
We present a generally covariant and parity-invariant two-frame field ("zwei-dreibein") action for gravity in three space-time dimensions that propagates two massive spin-2 modes, unitarily, and we use Hamiltonian methods to confirm the absence of unphysical degrees of freedom. We show how
Black holes in quasi-topological gravity and conformal couplings
Energy Technology Data Exchange (ETDEWEB)
Chernicoff, Mariano [Departamento de Física, Facultad de Ciencias, Universidad Nacional Autónoma de México,A.P. 70-542, México D.F. 04510 (Mexico); Fierro, Octavio [Departamento de Matemática y Física Aplicadas,Universidad Católica de la Santísima Concepción,Alonso de Rivera 2850, Concepción (Chile); Giribet, Gaston [Martin Fisher School of Physics, Brandeis University,Waltham, Massachusetts 02453 (United States); Departamento de Física, Universidad de Buenos Aires FCEN-UBA and IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Oliva, Julio [Departamento de Física, Universidad de Concepción,Casilla 160-C, Concepción (Chile)
2017-02-02
Lovelock theory of gravity provides a tractable model to investigate the effects of higher-curvature terms in the context of AdS/CFT. Yielding second order, ghost-free field equations, this theory represents a minimal setup in which higher-order gravitational couplings in asymptotically Anti-de Sitter (AdS) spaces, including black holes, can be solved analytically. This however has an obvious limitation as in dimensions lower than seven, the contribution from cubic or higher curvature terms is merely topological. Therefore, in order to go beyond quadratic order and study higher terms in AdS{sub 5} analytically, one is compelled to look for other toy models. One such model is the so-called quasi-topological gravity, which, despite being a higher-derivative theory, provides a tractable setup with R{sup 3} and R{sup 4} terms. In this paper, we investigate AdS{sub 5} black holes in quasi-topological gravity. We consider the theory conformally coupled to matter and in presence of Abelian gauge fields. We show that charged black holes in AdS{sub 5} which, in addition, exhibit a backreaction of the matter fields on the geometry can be found explicitly in this theory. These solutions generalize the black hole solution of quasi-topological gravity and exist in a region of the parameter spaces consistent with the constraints coming from causality and other consistency conditions. They have finite conserved charges and exhibit non-trivial thermodynamical properties.
Translation invariant time-dependent solutions to massive gravity II
Mourad, J.; Steer, D. A.
2014-06-01
This paper is a sequel to JCAP 12 (2013) 004 and is also devoted to translation-invariant solutions of ghost-free massive gravity in its moving frame formulation. Here we consider a mass term which is linear in the vielbein (corresponding to a β3 term in the 4D metric formulation) in addition to the cosmological constant. We determine explicitly the constraints, and from the initial value formulation show that the time-dependent solutions can have singularities at a finite time. Although the constraints give, as in the β1 case, the correct number of degrees of freedom for a massive spin two field, we show that the lapse function can change sign at a finite time causing a singular time evolution. This is very different to the β1 case where time evolution is always well defined. We conclude that the β3 mass term can be pathological and should be treated with care.
Extended DBI massive gravity with generalized fiducial metric
Chullaphan, Tossaporn; Tannukij, Lunchakorn; Wongjun, Pitayuth
2015-06-01
We consider an extended model of DBI massive gravity by generalizing the fiducial metric to be an induced metric on the brane corresponding to a domain wall moving in five-dimensional Schwarzschild-Anti-de Sitter spacetime. The model admits all solutions of FLRW metric including flat, closed and open geometries while the original one does not. The background solutions can be divided into two branches namely self-accelerating branch and normal branch. For the self-accelerating branch, the graviton mass plays the role of cosmological constant to drive the late-time acceleration of the universe. It is found that the number degrees of freedom of gravitational sector is not correct similar to the original DBI massive gravity. There are only two propagating degrees of freedom from tensor modes. For normal branch, we restrict our attention to a particular class of the solutions which provides an accelerated expansion of the universe. It is found that the number of degrees of freedom in the model is correct. However, at least one of them is ghost degree of freedom which always present at small scale implying that the theory is not stable.
Extended DBI massive gravity with generalized fiducial metric
International Nuclear Information System (INIS)
Chullaphan, Tossaporn; Tannukij, Lunchakorn; Wongjun, Pitayuth
2015-01-01
We consider an extended model of DBI massive gravity by generalizing the fiducial metric to be an induced metric on the brane corresponding to a domain wall moving in five-dimensional Schwarzschild-Anti-de Sitter spacetime. The model admits all solutions of FLRW metric including flat, closed and open geometries while the original one does not. The background solutions can be divided into two branches namely self-accelerating branch and normal branch. For the self-accelerating branch, the graviton mass plays the role of cosmological constant to drive the late-time acceleration of the universe. It is found that the number degrees of freedom of gravitational sector is not correct similar to the original DBI massive gravity. There are only two propagating degrees of freedom from tensor modes. For normal branch, we restrict our attention to a particular class of the solutions which provides an accelerated expansion of the universe. It is found that the number of degrees of freedom in the model is correct. However, at least one of them is ghost degree of freedom which always present at small scale implying that the theory is not stable.
Cosmology in massive gravity with effective composite metric
Energy Technology Data Exchange (ETDEWEB)
Heisenberg, Lavinia [Institute for Theoretical Studies, ETH Zurich Clausiusstrasse 47, 8092 Zurich (Switzerland); Refregier, Alexandre, E-mail: lavinia.heisenberg@eth-its.ethz.ch, E-mail: alexandre.refregier@phys.ethz.ch [Institute for Astronomy, Department of Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich (Switzerland)
2016-09-01
This paper is dedicated to scrutinizing the cosmology in massive gravity. A matter field of the dark sector is coupled to an effective composite metric while a standard matter field couples to the dynamical metric in the usual way. For this purpose, we study the dynamical system of cosmological solutions by using phase analysis, which provides an overview of the class of cosmological solutions in this setup. This also permits us to study the critical points of the cosmological equations together with their stability. We show the presence of stable attractor de Sitter critical points relevant to the late-time cosmic acceleration. Furthermore, we study the tensor, vector and scalar perturbations in the presence of standard matter fields and obtain the conditions for the absence of ghost and gradient instabilities. Hence, massive gravity in the presence of the effective composite metric can accommodate interesting dark energy phenomenology, that can be observationally distinguished from the standard model according to the expansion history and cosmic growth.
Nonlinear massive spin-2 field generated by higher derivative gravity
International Nuclear Information System (INIS)
Magnano, Guido; Sokolowski, Leszek M.
2003-01-01
We present a systematic exposition of the Lagrangian field theory for the massive spin-2 field generated in higher-derivative gravity upon reduction to a second-order theory by means of the appropriate Legendre transformation. It has been noticed by various authors that this nonlinear field overcomes the well-known inconsistency of the theory for a linear massive spin-2 field interacting with Einstein's gravity. Starting from a Lagrangian quadratically depending on the Ricci tensor of the metric, we explore the two possible second-order pictures usually called '(Helmholtz-)Jordan frame' and 'Einstein frame'. In spite of their mathematical equivalence, the two frames have different structural properties: in Einstein frame, the spin-2 field is minimally coupled to gravity, while in the other frame it is necessarily coupled to the curvature, without a separate kinetic term. We prove that the theory admits a unique and linearly stable ground state solution, and that the equations of motion are consistent, showing that these results can be obtained independently in either frame (each frame therefore provides a self-contained theory). The full equations of motion and the (variational) energy-momentum tensor for the spin-2 field in Einstein frame are given, and a simple but non-trivial exact solution to these equations is found. The comparison of the energy-momentum tensors for the spin-2 field in the two frames suggests that the Einstein frame is physically more acceptable. We point out that the energy-momentum tensor generated by the Lagrangian of the linearized theory is unrelated to the corresponding tensor of the full theory. It is then argued that the ghost-like nature of the nonlinear spin-2 field, found long ago in the linear approximation, may not be so harmful to classical stability issues, as has been expected
Gravity Model for Topological Features on a Cylindrical Manifold
Directory of Open Access Journals (Sweden)
Bayak I.
2008-04-01
Full Text Available A model aimed at understanding quantum gravity in terms of Birkho’s approach is discussed. The geometry of this model is constructed by using a winding map of Minkowski space into a R3 S1 -cylinder. The basic field of this model is a field of unit vectors defined through the velocity field of a flow wrapping the cylinder. The degeneration of some parts of the flow into circles (topological features results in in- homogeneities and gives rise to a scalar field, analogous to the gravitational field. The geometry and dynamics of this field are briefly discussed. We treat the intersections be- tween the topological features and the observer’s 3-space as matter particles and argue that these entities are likely to possess some quantum properties.
Black-hole decay and topological stability in quantum gravity
International Nuclear Information System (INIS)
Rodrigues, L.M.C.S.; Soares, I.D.; Zanelli, J.
1988-01-01
In the context of Quantum Gravity, the evolution of Schwarzschild black-holes is studied. The superspace of the theory is restricted to a class of geometries that contains the Schwarzschild solution for different masses as well as other geometries with different topologies. It is shown that, black-holes are topologically stable under quantum fluctuations but unstable under quantum processes of emission and absorption of gravitons. It is found that, the probability of emission behaves as exp (- α (M f - M i ), where M i and M f are the masses associated to the initial and final states, respectively and α is a positive constant of the order of 1. As the black-hole looses mass it evolves towards a state corresponding to a black-hole of very small that cannot be distinguished from a pure graviton state. (author) [pt
Killing vector fields in three dimensions: a method to solve massive gravity field equations
Energy Technology Data Exchange (ETDEWEB)
Guerses, Metin, E-mail: gurses@fen.bilkent.edu.t [Department of Mathematics, Faculty of Sciences, Bilkent University, 06800 Ankara (Turkey)
2010-10-21
Killing vector fields in three dimensions play an important role in the construction of the related spacetime geometry. In this work we show that when a three-dimensional geometry admits a Killing vector field then the Ricci tensor of the geometry is determined in terms of the Killing vector field and its scalars. In this way we can generate all products and covariant derivatives at any order of the Ricci tensor. Using this property we give ways to solve the field equations of topologically massive gravity (TMG) and new massive gravity (NMG) introduced recently. In particular when the scalars of the Killing vector field (timelike, spacelike and null cases) are constants then all three-dimensional symmetric tensors of the geometry, the Ricci and Einstein tensors, their covariant derivatives at all orders, and their products of all orders are completely determined by the Killing vector field and the metric. Hence, the corresponding three-dimensional metrics are strong candidates for solving all higher derivative gravitational field equations in three dimensions.
Anisotropic deformations of spatially open cosmology in massive gravity theory
Energy Technology Data Exchange (ETDEWEB)
Mazuet, Charles; Volkov, Mikhail S. [Laboratoire de Mathématiques et Physique Théorique CNRS-UMR 7350, Université de Tours, Parc de Grandmont, 37200 Tours (France); Mukohyama, Shinji, E-mail: charles.mazuet@lmpt.univ-tours.fr, E-mail: shinji.mukohyama@yukawa.kyoto-u.ac.jp, E-mail: volkov@lmpt.univ-tours.fr [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, 606-8502, Kyoto (Japan)
2017-04-01
We combine analytical and numerical methods to study anisotropic deformations of the spatially open homogeneous and isotropic cosmology in the ghost free massive gravity theory with flat reference metric. We find that if the initial perturbations are not too strong then the physical metric relaxes back to the isotropic de Sitter state. However, the dumping of the anisotropies is achieved at the expense of exciting the Stueckelberg fields in such a way that the reference metric changes and does not share anymore with the physical metric the same rotational and translational symmetries. As a result, the universe evolves towards a fixed point which does not coincide with the original solution, but for which the physical metric is still de Sitter. If the initial perturbation is strong, then its evolution generically leads to a singular anisotropic state or, for some parameter values, to a decay into flat spacetime. We also present an infinite dimensional family of new homogeneous and isotropic cosmologies in the theory.
Hawking–Page phase transition in new massive gravity
Directory of Open Access Journals (Sweden)
Shao-Jun Zhang
2015-07-01
Full Text Available We consider Hawking–Page phase transition between the BTZ black hole with M≥0 and the thermal soliton with M=−1 in new massive gravity. By comparing the on-shell free energies, we can see that there exists a critical temperature. The thermal soliton is more probable than the black hole below the critical temperature while the black hole is more probable than the thermal soliton above the critical temperature. By consistently constructing the off-shell free energies taking into account the conical singularity, we show that there exist infinite non-equilibrium states connecting the BTZ black hole and the thermal soliton, so that they provide a picture of continuous evolution of the phase transition.
APS Beyond Positivity Bounds and the Fate of Massive Gravity
Bellazzini, Brando; Serra, Javi; Sgarlata, Francesco
2018-04-18
We constrain effective field theories by going beyond the familiar positivity bounds that follow from unitarity, analyticity, and crossing symmetry of the scattering amplitudes. As interesting examples, we discuss the implications of the bounds for the Galileon and ghost-free massive gravity. The combination of our theoretical bounds with the experimental constraints on the graviton mass implies that the latter is either ruled out or unable to describe gravitational phenomena, let alone to consistently implement the Vainshtein mechanism, down to the relevant scales of fifth-force experiments, where general relativity has been successfully tested. We also show that the Galileon theory must contain symmetry-breaking terms that are at most one-loop suppressed compared to the symmetry-preserving ones. We comment as well on other interesting applications of our bounds.
Impact of topology in foliated quantum Einstein gravity.
Houthoff, W B; Kurov, A; Saueressig, F
2017-01-01
We use a functional renormalization group equation tailored to the Arnowitt-Deser-Misner formulation of gravity to study the scale dependence of Newton's coupling and the cosmological constant on a background spacetime with topology [Formula: see text]. The resulting beta functions possess a non-trivial renormalization group fixed point, which may provide the high-energy completion of the theory through the asymptotic safety mechanism. The fixed point is robust with respect to changing the parametrization of the metric fluctuations and regulator scheme. The phase diagrams show that this fixed point is connected to a classical regime through a crossover. In addition the flow may exhibit a regime of "gravitational instability", modifying the theory in the deep infrared. Our work complements earlier studies of the gravitational renormalization group flow on a background topology [Formula: see text] (Biemans et al. Phys Rev D 95:086013, 2017, Biemans et al. arXiv:1702.06539, 2017) and establishes that the flow is essentially independent of the background topology.
Impact of topology in foliated quantum Einstein gravity
Energy Technology Data Exchange (ETDEWEB)
Houthoff, W.B.; Saueressig, F. [Radboud University Nijmegen, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Nijmegen (Netherlands); Kurov, A. [Radboud University Nijmegen, Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Nijmegen (Netherlands); Moscow State University, Department of Theoretical Physics, Moscow (Russian Federation)
2017-07-15
We use a functional renormalization group equation tailored to the Arnowitt-Deser-Misner formulation of gravity to study the scale dependence of Newton's coupling and the cosmological constant on a background spacetime with topology S{sup 1} x S{sup d}. The resulting beta functions possess a non-trivial renormalization group fixed point, which may provide the high-energy completion of the theory through the asymptotic safety mechanism. The fixed point is robust with respect to changing the parametrization of the metric fluctuations and regulator scheme. The phase diagrams show that this fixed point is connected to a classical regime through a crossover. In addition the flow may exhibit a regime of ''gravitational instability'', modifying the theory in the deep infrared. Our work complements earlier studies of the gravitational renormalization group flow on a background topology S{sup 1} x T{sup d} (Biemans et al. Phys Rev D 95:086013, 2017, Biemans et al. arXiv:1702.06539, 2017) and establishes that the flow is essentially independent of the background topology. (orig.)
f (T) Non-linear Massive Gravity and the Cosmic Acceleration
International Nuclear Information System (INIS)
Wu You; Chen Zu-Cheng; Wei Hao; Wang Jia-Xin
2015-01-01
Inspired by the f (R) non-linear massive gravity, we propose a new kind of modified gravity model, namely f (T) non-linear massive gravity, by adding the dRGT mass term reformulated in the vierbein formalism, to the f (T) theory. We then investigate the cosmological evolution of f (T) massive gravity, and constrain it by using the latest observational data. We find that it slightly favors a crossing of the phantom divide line from the quintessence-like phase (w_d_e > −1) to the phantom-like one (w_d_e < −1) as redshift decreases. (paper)
Extensions of three-dimensional higher-derivative gravity
Yin, Yihao
2013-01-01
Driedimensionale zwaartekrachtmodellen met hogere afgeleiden, met in het bijzonder New Massive Gravity (NMG) en Topologically Massive Gravity (TMG), zijn speelmodellen die gebruikt worden door theoretische natuurkundigen om te onderzoeken hoe Einsteins algemene relativiteitstheorie verbeterd kan
Hairy black holes in cubic quasi-topological gravity
Energy Technology Data Exchange (ETDEWEB)
Dykaar, Hannah [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Department of Physics, McGill University,3600 rue University, Montreal, QC, H3A 2T8 (Canada); Hennigar, Robie A.; Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada)
2017-05-09
We construct a class of five dimensional black hole solutions to cubic quasi-topological gravity with conformal scalar hair and study their thermodynamics. We find these black holes provide the second example of black hole λ-lines: a line of second order (continuous) phase transitions, akin to the fluid/superfluid transition of {sup 4}He. Examples of isolated critical points are found for spherical black holes, marking the first in the literature to date. We also find various novel and interesting phase structures, including an isolated critical point occurring in conjunction with a double reentrant phase transition. The AdS vacua of the theory are studied, finding ghost-free configurations where the scalar field takes on a non-zero constant value, in notable contrast to the five dimensional Lovelock case.
On the background independence of two-dimensional topological gravity
Imbimbo, Camillo
1995-04-01
We formulate two-dimensional topological gravity in a background covariant Lagrangian framework. We derive the Ward identities which characterize the dependence of physical correlators on the background world-sheet metric defining the gauge-slice. We point out the existence of an "anomaly" in Ward identitites involving correlators of observables with higher ghost number. This "anomaly" represents an obstruction for physical correlators to be globally defined forms on moduli space which could be integrated in a background independent way. Starting from the anomalous Ward identities, we derive "descent" equations whose solutions are cocycles of the Lie algebra of the diffeomorphism group with values in the space of local forms on the moduli space. We solve the descent equations and provide explicit formulas for the cocycles, which allow for the definition of background independent integrals of physical correlators on the moduli space.
Canonical formulations of full nonlinear topologically massive gravity
International Nuclear Information System (INIS)
Deser, S.; Xiang, X.
1991-01-01
First-order forms of the complete nonlinear Einstein plus Chern-Simons third-derivative-order action are exhibited in both metric and dreibein forms. The 'hamiltonians' are combinations of diffeomorphism and tangent space rotation generators as expected of generally covariant systems; the pure Chern-Simons hamiltonian has an additional, conformal transformation, term. These constraints reduce the apparent number of degrees of freedom to 1 and 0 respectively. The constraint algebras close, as required by this counting, without second-class constraints. The nature of the noninvariant terms in the Chern-Simons lagrangian density is discussed. For comparison, the linearized limit and the corresponding nonabelian vector action's canonical form are also given. (orig.)
On couplings to matter in massive (bi-)gravity
International Nuclear Information System (INIS)
Rham, Claudia de; Ribeiro, Raquel H; Heisenberg, Lavinia
2015-01-01
We investigate the coupling to matter in ghost-free massive (bi-)gravity. When species in the matter sector couple covariantly to only one metric, we show that at one-loop these couplings do not spoil the special structure of the graviton potential. When the same species couples directly to both metrics we show that a ghost is present at the classical level and that loops destroy the special structure of the potential at an unacceptably low scale. We then propose a new ‘composite’ effective metric built out of both metrics. When matter fields couple covariantly to this effective metric, the would be Boulware–Deser (BD) ghost is absent in different representative limits. At one-loop such couplings do not detune the special structure of the potential. We conjecture that matter can couple covariantly to that effective metric in all generality without introducing any BD ghost below a cut-off scale parametrically larger than the strong coupling scale. We also discuss alternative couplings to matter where the kinetic and potential terms of the matter field couple to different metrics. In both cases we discuss preliminary implications for cosmology. (paper)
Black string in dRGT massive gravity
Energy Technology Data Exchange (ETDEWEB)
Tannukij, Lunchakorn [Mahidol University, Department of Physics, Faculty of Science, Bangkok (Thailand); Hanyang University, Department of Physics, Seoul (Korea, Republic of); Naresuan University, The Institute for Fundamental Study, Phitsanulok (Thailand); Wongjun, Pitayuth [Naresuan University, The Institute for Fundamental Study, Phitsanulok (Thailand); Ministry of Education, Thailand Center of Excellence in Physics, Bangkok (Thailand); Ghosh, Suchant G. [Jamia Millia Islamia, Centre of Theoretical Physics, New Delhi (India); University of Kwazulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Durban (South Africa)
2017-12-15
We present a cylindrically symmetric solution, both charged and uncharged, which is known as a black string solution to the nonlinear ghost-free massive gravity found by de Rham, Gabadadze, and Tolley (dRGT). This ''dRGT black string'' can be thought of as a generalization of the black string solution found by Lemos. Moreover, the dRGT black string solution includes other classes of black string solution such as the monopole-black string ones since the graviton mass contributes to the global monopole term as well as the cosmological-constant term. To investigate the solution, we compute mass, temperature, and entropy of the dRGT black string. We found that the existence of the graviton mass drastically affects the thermodynamics of the black string. Furthermore, the Hawking-Page phase transition is found to be possible for the dRGT black string as well as the charged dRGT black string. The dRGT black string solution is thermodynamically stable for r > r{sub c} with negative thermodynamical potential and positive heat capacity while it is unstable for r < r{sub c} where the potential is positive. (orig.)
Constrained dynamics of universally coupled massive spin 2-spin 0 gravities
International Nuclear Information System (INIS)
Pitts, J Brian
2006-01-01
The 2-parameter family of massive variants of Einsteins gravity (on a Minkowski background) found by Ogievetsky and Polubarinov by excluding lower spins can also be derived using universal coupling. A Dirac-Bergmann constrained dynamics analysis seems not to have been presented for these theories, the Freund-Maheshwari-Schonberg special case, or any other massive gravity beyond the linear level treated by Marzban, Whiting and van Dam. Here the Dirac-Bergmann apparatus is applied to these theories. A few remarks are made on the question of positive energy. Being bimetric, massive gravities have a causality puzzle, but it appears soluble by the introduction and judicious use of gauge freedom
Topological black holes in Lovelock-Born-Infeld gravity
International Nuclear Information System (INIS)
Dehghani, M. H.; Alinejadi, N.; Hendi, S. H.
2008-01-01
In this paper, we present topological black holes of third order Lovelock gravity in the presence of cosmological constant and nonlinear electromagnetic Born-Infeld field. Depending on the metric parameters, these solutions may be interpreted as black hole solutions with inner and outer event horizons, an extreme black hole or naked singularity. We investigate the thermodynamics of asymptotically flat solutions and show that the thermodynamic and conserved quantities of these black holes satisfy the first law of thermodynamic. We also endow the Ricci flat solutions with a global rotation and calculate the finite action and conserved quantities of these class of solutions by using the counterterm method. We compute the entropy through the use of the Gibbs-Duhem relation and find that the entropy obeys the area law. We obtain a Smarr-type formula for the mass as a function of the entropy, the angular momenta, and the charge, and compute temperature, angular velocities, and electric potential and show that these thermodynamic quantities coincide with their values which are computed through the use of geometry. Finally, we perform a stability analysis for this class of solutions in both the canonical and the grand-canonical ensemble and show that the presence of a nonlinear electromagnetic field and higher curvature terms has no effect on the stability of the black branes, and they are stable in the whole phase space
Can Topology and Geometry be Measured by an Operator Measurement in Quantum Gravity?
Berenstein, David; Miller, Alexandra
2017-06-30
In the context of Lin-Lunin-Maldacena geometries, we show that superpositions of classical coherent states of trivial topology can give rise to new classical limits where the topology of spacetime has changed. We argue that this phenomenon implies that neither the topology nor the geometry of spacetime can be the result of an operator measurement. We address how to reconcile these statements with the usual semiclassical analysis of low energy effective field theory for gravity.
Topologically massive gauge theories and their dual factorized gauge-invariant formulation
International Nuclear Information System (INIS)
Bertrand, Bruno; Govaerts, Jan
2007-01-01
There exists a well-known duality between the Maxwell-Chern-Simons theory and the 'self-dual' massive model in (2 + 1) dimensions. This dual description may be extended to topologically massive gauge theories (TMGT) for forms of arbitrary rank and in any dimension. This communication introduces the construction of this type of duality through a reparametrization of the 'master' theory action. The dual action thereby obtained preserves the full gauge symmetry structure of the original theory. Furthermore, the dual action is factorized into a propagating sector of massive gauge-invariant variables and a decoupled sector of gauge-variant variables defining a pure topological field theory. Combining the results obtained within the Lagrangian and Hamiltonian formulations, a completed structure for a gauge-invariant dual factorization of TMGT is thus achieved. (fast track communication)
Onset of dynamical chaos in topologically massive gauge theories
International Nuclear Information System (INIS)
Giansanti, A.; Simic, P.D.
1988-01-01
The onset of dynamical chaos is studied numerically in (2+1)-dimensional non-Abelian field theory with the Chern-Simons topological term. In the limit of strong fields, slowly varying in space (spatially homogeneous fields), this theory is an analog to a system of three charged particles moving in a plane in an orthogonal magnetic field and under the influence of a quartic potential. The ''phase transition'' (order chaos) is observed within a narrow energy range. The threshold of the transition depends on the sign of the angular momentum of the field reflecting parity violation in the underlying field theory. The transition region is investigated in some detail and the hyperfine structure of order-chaos-order-... transitions is observed suggesting the necessity of probabilistic description
International Nuclear Information System (INIS)
Bertrand, Bruno; Govaerts, Jan
2007-01-01
Abelian topologically massive gauge theories (TMGT) provide a topological mechanism to generate mass for a bosonic p-tensor field in any spacetime dimension. These theories include the (2+1)-dimensional Maxwell-Chern-Simons and (3+1)-dimensional Cremmer-Scherk actions as particular cases. Within the Hamiltonian formulation, the embedded topological field theory (TFT) sector related to the topological mass term is not manifest in the original phase space. However, through an appropriate canonical transformation, a gauge-invariant factorization of phase space into two orthogonal sectors is feasible. The first of these sectors includes canonically conjugate gauge-invariant variables with free massive excitations. The second sector, which decouples from the total Hamiltonian, is equivalent to the phase-space description of the associated non-dynamical pure TFT. Within canonical quantization, a likewise factorization of quantum states thus arises for the full spectrum of TMGT in any dimension. This new factorization scheme also enables a definition of the usual projection from TMGT onto topological quantum field theories in a most natural and transparent way. None of these results rely on any gauge-fixing procedure whatsoever
Spontaneous Lorentz and diffeomorphism violation, massive modes, and gravity
International Nuclear Information System (INIS)
Bluhm, Robert; Fung Shuhong; Kostelecky, V. Alan
2008-01-01
Theories with spontaneous local Lorentz and diffeomorphism violation contain massless Nambu-Goldstone modes, which arise as field excitations in the minimum of the symmetry-breaking potential. If the shape of the potential also allows excitations above the minimum, then an alternative gravitational Higgs mechanism can occur in which massive modes involving the metric appear. The origin and basic properties of the massive modes are addressed in the general context involving an arbitrary tensor vacuum value. Special attention is given to the case of bumblebee models, which are gravitationally coupled vector theories with spontaneous local Lorentz and diffeomorphism violation. Mode expansions are presented in both local and spacetime frames, revealing the Nambu-Goldstone and massive modes via decomposition of the metric and bumblebee fields, and the associated symmetry properties and gauge fixing are discussed. The class of bumblebee models with kinetic terms of the Maxwell form is used as a focus for more detailed study. The nature of the associated conservation laws and the interpretation as a candidate alternative to Einstein-Maxwell theory are investigated. Explicit examples involving smooth and Lagrange-multiplier potentials are studied to illustrate features of the massive modes, including their origin, nature, dispersion laws, and effects on gravitational interactions. In the weak static limit, the massive mode and Lagrange-multiplier fields are found to modify the Newton and Coulomb potentials. The nature and implications of these modifications are examined.
Infrared lessons for ultraviolet gravity: the case of massive gravity and Born-Infeld
Beltrán Jiménez, Jose; Heisenberg, Lavinia; Olmo, Gonzalo J.
2014-11-01
We generalize the ultraviolet sector of gravitation via a Born-Infeld action using lessons from massive gravity. The theory contains all of the elementary symmetric polynomials and is treated in the Palatini formalism. We show how the connection can be solved algebraically to be the Levi-Civita connection of an effective metric. The non-linearity of the algebraic equations yields several branches, one of which always reduces to General Relativity at low curvatures. We explore in detail a minimal version of the theory, for which we study solutions in the presence of a perfect fluid with special attention to the cosmological evolution. In vacuum we recover Ricci-flat solutions, but also an additional physical solution corresponding to an Einstein space. The existence of two physical branches remains for non-vacuum solutions and, in addition, the branch that connects to the Einstein space in vacuum is not very sensitive to the specific value of the energy density. For the branch that connects to the General Relativity limit we generically find three behaviours for the Hubble function depending on the equation of state of the fluid, namely: either there is a maximum value for the energy density that connects continuously with vacuum, or the energy density can be arbitrarily large but the Hubble function saturates and remains constant at high energy densities, or the energy density is unbounded and the Hubble function grows faster than in General Relativity. The second case is particularly interesting because it could offer an interesting inflationary epoch even in the presence of a dust component. Finally, we discuss the possibility of avoiding certain types of singularities within the minimal model.
Covariant constraints for generic massive gravity and analysis of its characteristics
DEFF Research Database (Denmark)
Deser, S.; Sandora, M.; Waldron, A.
2014-01-01
We perform a covariant constraint analysis of massive gravity valid for its entire parameter space, demonstrating that the model generically propagates 5 degrees of freedom; this is also verified by a new and streamlined Hamiltonian description. The constraint's covariant expression permits...
Vacaru, Sergiu I
2014-01-01
The fundamental field equations in modified gravity (including general relativity; massive and bimetric theories; Ho\\vrava-Lifshits, HL; Einstein--Finsler gravity extensions etc) posses an important decoupling property with respect to nonholonomic frames with 2 (or 3) +2+2+... spacetime decompositions. This allows us to construct exact solutions with generic off--diagonal metrics depending on all spacetime coordinates via generating and integration functions containing (un-) broken symmetry parameters. Such nonholonomic configurations/ models have a nice ultraviolet behavior and seem to be ghost free and (super) renormalizable in a sense of covariant and/or massive modifications of HL gravity. The apparent noncommutativity and breaking of Lorentz invariance by quantum effects can be encoded into fibers of noncommutative tangent Lorentz bundles for corresponding "partner" anisotropically induced theories. We show how the constructions can be extended to include conjectured covariant reonormalizable models with...
Holographic thermalization and generalized Vaidya-AdS solutions in massive gravity
Hu, Ya-Peng; Zeng, Xiao-Xiong; Zhang, Hai-Qing
2017-02-01
We investigate the effect of massive graviton on the holographic thermalization process. Before doing this, we first find out the generalized Vaidya-AdS solutions in the de Rham-Gabadadze-Tolley (dRGT) massive gravity by directly solving the gravitational equations. Then, we study the thermodynamics of these Vaidya-AdS solutions by using the Misner-Sharp energy and unified first law, which also shows that the massive gravity is in a thermodynamic equilibrium state. Moreover, we adopt the two-point correlation function at equal time to explore the thermalization process in the dual field theory, and to see how the graviton mass parameter affects this process from the viewpoint of AdS/CFT correspondence. Our results show that the graviton mass parameter will increase the holographic thermalization process.
Holographic thermalization and generalized Vaidya-AdS solutions in massive gravity
Energy Technology Data Exchange (ETDEWEB)
Hu, Ya-Peng, E-mail: huyp@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Instituut-Lorentz for Theoretical Physics, Leiden University, Niels Bohrweg 2, Leiden 2333 CA (Netherlands); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Zeng, Xiao-Xiong, E-mail: xxzengphysics@163.com [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190 (China); School of Science, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Hai-Qing, E-mail: H.Q.Zhang@uu.nl [Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Princetonplein 5, 3584 CC Utrecht (Netherlands)
2017-02-10
We investigate the effect of massive graviton on the holographic thermalization process. Before doing this, we first find out the generalized Vaidya-AdS solutions in the de Rham–Gabadadze–Tolley (dRGT) massive gravity by directly solving the gravitational equations. Then, we study the thermodynamics of these Vaidya-AdS solutions by using the Misner–Sharp energy and unified first law, which also shows that the massive gravity is in a thermodynamic equilibrium state. Moreover, we adopt the two-point correlation function at equal time to explore the thermalization process in the dual field theory, and to see how the graviton mass parameter affects this process from the viewpoint of AdS/CFT correspondence. Our results show that the graviton mass parameter will increase the holographic thermalization process.
Holographic thermalization and generalized Vaidya-AdS solutions in massive gravity
International Nuclear Information System (INIS)
Hu, Ya-Peng; Zeng, Xiao-Xiong; Zhang, Hai-Qing
2017-01-01
We investigate the effect of massive graviton on the holographic thermalization process. Before doing this, we first find out the generalized Vaidya-AdS solutions in the de Rham–Gabadadze–Tolley (dRGT) massive gravity by directly solving the gravitational equations. Then, we study the thermodynamics of these Vaidya-AdS solutions by using the Misner–Sharp energy and unified first law, which also shows that the massive gravity is in a thermodynamic equilibrium state. Moreover, we adopt the two-point correlation function at equal time to explore the thermalization process in the dual field theory, and to see how the graviton mass parameter affects this process from the viewpoint of AdS/CFT correspondence. Our results show that the graviton mass parameter will increase the holographic thermalization process.
dRGT theory of massive gravity from spontaneous symmetry breaking
Torabian, Mahdi
2018-05-01
In this note we propose a topological action for a Poincare times diffeomorphism invariant gauge theory. We show that there is Higgs phase where the gauge symmetry is spontaneous broken to a diagonal Lorentz subgroup and gives the Einstein-Hilbert action plus the dRGT potential terms. In this vacuum, there are five (three from Goldstone modes) propagating degrees of freedom which form polarizations of a massive spin 2 particle, an extra healthy heavy scalar (Higgs) mode and no Boulware-Deser ghost mode. We further show that the action can be derived in a limit from a topological de Sitter invariant gauge theory in 4 dimensions.
Nonperturbative sum over topologies in 2-D Lorentzian quantum gravity
Loll, R.; Westra, W.; Zohren, S.
The recent progress in the Causal Dynamical Triangulations (CDT) approach to quantum gravity indicates that gravitation is nonperturbatively renormalizable. We review some of the latest results in 1+1 and 3+1 dimensions with special emphasis on the 1+1 model. In particular we discuss a
Discrete gravity as a topological field theorywith light-like curvature defects
Energy Technology Data Exchange (ETDEWEB)
Wieland, Wolfgang [Perimeter Institute for Theoretical Physics,31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada)
2017-05-29
I present a model of discrete gravity as a topological field theory with defects. The theory has no local degrees of freedom and the gravitational field is trivial everywhere except at a number of intersecting null surfaces. At these null surfaces, the gravitational field can be singular, representing a curvature defect propagating at the speed of light. The underlying action is local and it is studied in both its Lagrangian and Hamiltonian formulation. The canonically conjugate variables on the null surfaces are a spinor and a spinor-valued two-surface density, which are coupled to a topological field theory for the Lorentz connection in the bulk. I discuss the relevance of the model for non-perturbative approaches to quantum gravity, such as loop quantum gravity, where similar variables have recently appeared as well.
Energy Technology Data Exchange (ETDEWEB)
Zou, De-Cheng; Yue, Ruihong [Yangzhou University, Center for Gravitation and Cosmology, College of Physical Science and Technology, Yangzhou (China); Liu, Yunqi [Huazhong University of Science and Technology, School of Physics, Wuhan (China)
2017-06-15
In this work, we utilize the quasinormal modes (QNMs) of a massless scalar perturbation to probe the Van der Waals-like small and large black holes (SBH/LBH) phase transition of charged topological Anti-de Sitter (AdS) black holes in four-dimensional massive gravity. We find that the signature of this SBH/LBH phase transition is detected in the isobaric as well as in the isothermal process. This further supports the idea that the QNMs can be an efficient tool to investigate the thermodynamical phase transition. (orig.)
Topologically nontrivial black holes in Lovelock-Born-Infeld gravity
Farhangkhah, N.
2018-04-01
We present the black hole solutions possessing horizon with nonconstant-curvature and additional scalar restrictions on the base manifold in Lovelock gravity coupled to Born-Infeld (BI) nonlinear electrodynamics. The asymptotic and near origin behavior of the metric is presented and we analyze different behaviors of the singularity. We find that, in contrast to the case of black hole solutions of BI-Lovelock gravity with constant curvature horizon and Maxwell-Lovelock gravity with non constant horizon which have only timelike singularities, spacelike, and timelike singularities may exist for BI-Lovelock black holes with nonconstant curvature horizon. By calculating the thermodynamic quantities, we study the effects of nonlinear electrodynamics via the Born-Infeld action. Stability analysis shows that black holes with positive sectional curvature, κ , possess an intermediate unstable phase and large and small black holes are stable. We see that while Ricci flat Lovelock-Born-Infeld black holes having exotic horizons are stable in the presence of Maxwell field or either Born Infeld field with large born Infeld parameter β , unstable phase appears for smaller values of β , and therefore nonlinearity brings in the instability.
International Nuclear Information System (INIS)
Klusoň, Josef; Nojiri, Shin'ichi; Odintsov, Sergei D.
2013-01-01
We propose new version of massive F(R) gravity which is natural generalization of convenient massive ghost-free gravity. Its Hamiltonian formulation in scalar-tensor frame is developed. We show that such F(R) theory is ghost-free. The cosmological evolution of such theory is investigated. Despite the strong Bianchi identity constraint the possibility of cosmic acceleration (especially, in the presence of cold dark matter) is established. Ghost-free massive F(R,T) gravity is also proposed
Unusual square roots in the ghost-free theory of massive gravity
Golovnev, Alexey; Smirnov, Fedor
2017-06-01
A crucial building block of the ghost free massive gravity is the square root function of a matrix. This is a problematic entity from the viewpoint of existence and uniqueness properties. We accurately describe the freedom of choosing a square root of a (non-degenerate) matrix. It has discrete and (in special cases) continuous parts. When continuous freedom is present, the usual perturbation theory in terms of matrices can be critically ill defined for some choices of the square root. We consider the new formulation of massive and bimetric gravity which deals directly with eigenvalues (in disguise of elementary symmetric polynomials) instead of matrices. It allows for a meaningful discussion of perturbation theory in such cases, even though certain non-analytic features arise.
Spherically symmetric analysis on open FLRW solution in non-linear massive gravity
Energy Technology Data Exchange (ETDEWEB)
Chiang, Chien-I; Izumi, Keisuke; Chen, Pisin, E-mail: chienichiang@berkeley.edu, E-mail: izumi@phys.ntu.edu.tw, E-mail: chen@slac.stanford.edu [Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 10617, Taiwan (China)
2012-12-01
We study non-linear massive gravity in the spherically symmetric context. Our main motivation is to investigate the effect of helicity-0 mode which remains elusive after analysis of cosmological perturbation around an open Friedmann-Lemaitre-Robertson-Walker (FLRW) universe. The non-linear form of the effective energy-momentum tensor stemming from the mass term is derived for the spherically symmetric case. Only in the special case where the area of the two sphere is not deviated away from the FLRW universe, the effective energy momentum tensor becomes completely the same as that of cosmological constant. This opens a window for discriminating the non-linear massive gravity from general relativity (GR). Indeed, by further solving these spherically symmetric gravitational equations of motion in vacuum to the linear order, we obtain a solution which has an arbitrary time-dependent parameter. In GR, this parameter is a constant and corresponds to the mass of a star. Our result means that Birkhoff's theorem no longer holds in the non-linear massive gravity and suggests that energy can probably be emitted superluminously (with infinite speed) on the self-accelerating background by the helicity-0 mode, which could be a potential plague of this theory.
Novel symmetries in Weyl-invariant gravity with massive gauge field
Energy Technology Data Exchange (ETDEWEB)
Abhinav, K. [S.N. Bose National Centre for Basic Sciences, Salt Lake, Kolkata (India); Shukla, A.; Panigrahi, P.K. [Indian Institute of Science Education and Research Kolkata, Mohanpur (India)
2016-11-15
The background field method is used to linearize the Weyl-invariant scalar-tensor gravity, coupled with a Stueckelberg field. For a generic background metric, this action is found not to be invariant, under both a diffeomorphism and generalized Weyl symmetry, the latter being a combination of gauge and Weyl transformations. Interestingly, the quadratic Lagrangian, emerging from a background of Minkowski metric, respects both transformations independently. The Becchi-Rouet-Stora-Tyutin symmetry of scalar-tensor gravity coupled with a Stueckelberg-like massive gauge particle, possessing a diffeomorphism and generalized Weyl symmetry, reveals that in both cases negative-norm states with unphysical degrees of freedom do exist. We then show that, by combining diffeomorphism and generalized Weyl symmetries, all the ghost states decouple, thereby removing the unphysical redundancies of the theory. During this process, the scalar field does not represent any dynamic mode, yet modifies the usual harmonic gauge condition through non-minimal coupling with gravity. (orig.)
A spectre is haunting the cosmos: quantum stability of massive gravity with ghosts
International Nuclear Information System (INIS)
Könnig, Frank; Nersisyan, Henrik; Akrami, Yashar; Amendola, Luca; Zumalacárregui, Miguel
2016-01-01
Many theories of modified gravity with higher order derivatives are usually ignored because of serious problems that appear due to an additional ghost degree of freedom. Most dangerously, it causes an immediate decay of the vacuum. However, breaking Lorentz invariance can cure such abominable behavior. By analyzing a model that describes a massive graviton together with a remaining Boulware-Deser ghost mode we show that even ghostly theories of modified gravity can yield models that are viable at both classical and quantum levels and, therefore, they should not generally be ruled out. Furthermore, we identify the most dangerous quantum scattering process that has the main impact on the decay time and find differences to simple theories that only describe an ordinary scalar field and a ghost. Additionally, constraints on the parameters of the theory including some upper bounds on the Lorentz-breaking cutoff scale are presented. In particular, for a simple theory of massive gravity we find that a breaking of Lorentz invariance is allowed to happen even at scales above the Planck mass. Finally, we discuss the relevance to other theories of modified gravity.
Equations of motion for massive spin 2 field coupled to gravity
International Nuclear Information System (INIS)
Buchbinder, I.L.; Gitman, D.M.; Krykhtin, V.A.; Pershin, V.D.
2000-01-01
We investigate the problems of consistency and causality for the equations of motion describing massive spin two field in external gravitational and massless scalar dilaton fields in arbitrary spacetime dimension. From the field theoretical point of view we consider a general classical action with non-minimal couplings and find gravitational and dilaton background on which this action describes a theory consistent with the flat space limit. In the case of pure gravitational background all field components propagate causally. We show also that the massive spin two field can be consistently described in arbitrary background by means of the lagrangian representing an infinite series in the inverse mass. Within string theory we obtain equations of motion for the massive spin two field coupled to gravity from the requirement of quantum Weyl invariance of the corresponding two-dimensional sigma-model. In the lowest order in α' we demonstrate that these effective equations of motion coincide with consistent equations derived in field theory
Lifshitz black branes and DC transport coefficients in massive Einstein-Maxwell-dilaton gravity
Kuang, Xiao-Mei; Papantonopoulos, Eleftherios; Wu, Jian-Pin; Zhou, Zhenhua
2018-03-01
We construct analytical Lifshitz massive black brane solutions in massive Einstein-Maxwell-dilaton gravity theory. We also study the thermodynamics of these black brane solutions and obtain the thermodynamical stability conditions. On the dual nonrelativistic boundary field theory with Lifshitz symmetry, we analytically compute the DC transport coefficients, including the electric conductivity, thermoelectric conductivity, and thermal conductivity. The novel property of our model is that the massive term supports the Lifshitz black brane solutions with z ≠1 in such a way that the DC transport coefficients in the dual field theory are finite. We also find that the Wiedemann-Franz law in this dual boundary field theory is violated, which indicates that it may involve strong interactions.
Pitts, J. Brian
2016-02-01
What if gravity satisfied the Klein-Gordon equation? Both particle physics from the 1920-30s and the 1890s Neumann-Seeliger modification of Newtonian gravity with exponential decay suggest considering a "graviton mass term" for gravity, which is algebraic in the potential. Unlike Nordström's "massless" theory, massive scalar gravity is strictly special relativistic in the sense of being invariant under the Poincaré group but not the 15-parameter Bateman-Cunningham conformal group. It therefore exhibits the whole of Minkowski space-time structure, albeit only indirectly concerning volumes. Massive scalar gravity is plausible in terms of relativistic field theory, while violating most interesting versions of Einstein's principles of general covariance, general relativity, equivalence, and Mach. Geometry is a poor guide to understanding massive scalar gravity(s): matter sees a conformally flat metric due to universal coupling, but gravity also sees the rest of the flat metric (barely or on long distances) in the mass term. What is the 'true' geometry, one might wonder, in line with Poincaré's modal conventionality argument? Infinitely many theories exhibit this bimetric 'geometry,' all with the total stress-energy's trace as source; thus geometry does not explain the field equations. The irrelevance of the Ehlers-Pirani-Schild construction to a critique of conventionalism becomes evident when multi-geometry theories are contemplated. Much as Seeliger envisaged, the smooth massless limit indicates underdetermination of theories by data between massless and massive scalar gravities-indeed an unconceived alternative. At least one version easily could have been developed before General Relativity; it then would have motivated thinking of Einstein's equations along the lines of Einstein's newly re-appreciated "physical strategy" and particle physics and would have suggested a rivalry from massive spin 2 variants of General Relativity (massless spin 2, Pauli and Fierz
TOPOLOGY OF A LARGE-SCALE STRUCTURE AS A TEST OF MODIFIED GRAVITY
International Nuclear Information System (INIS)
Wang Xin; Chen Xuelei; Park, Changbom
2012-01-01
The genus of the isodensity contours is a robust measure of the topology of a large-scale structure, and it is relatively insensitive to nonlinear gravitational evolution, galaxy bias, and redshift-space distortion. We show that the growth of density fluctuations is scale dependent even in the linear regime in some modified gravity theories, which opens a new possibility of testing the theories observationally. We propose to use the genus of the isodensity contours, an intrinsic measure of the topology of the large-scale structure, as a statistic to be used in such tests. In Einstein's general theory of relativity, density fluctuations grow at the same rate on all scales in the linear regime, and the genus per comoving volume is almost conserved as structures grow homologously, so we expect that the genus-smoothing-scale relation is basically time independent. However, in some modified gravity models where structures grow with different rates on different scales, the genus-smoothing-scale relation should change over time. This can be used to test the gravity models with large-scale structure observations. We study the cases of the f(R) theory, DGP braneworld theory as well as the parameterized post-Friedmann models. We also forecast how the modified gravity models can be constrained with optical/IR or redshifted 21 cm radio surveys in the near future.
Topological aspects of classical and quantum (2+1)-dimensional gravity
International Nuclear Information System (INIS)
Soda, Jiro.
1990-03-01
In order to understand (3+1)-dimensional gravity, (2+1)-dimensional gravity is studied as a toy model. Our emphasis is on its topological aspects, because (2+1)-dimensional gravity without matter fields has no local dynamical degrees of freedom. Starting from a review of the canonical ADM formalism and York's formalism for the initial value problem, we will solve the evolution equations of (2+1)-dimensional gravity with a cosmological constant in the case of g=0 and g=1, where g is the genus of Riemann surface. The dynamics of it is understood as the geodesic motion in the moduli space. This remarkable fact is the same with the case of (2+1)-dimensional pure gravity and seen more apparently from the action level. Indeed we will show the phase space reduction of (2+1)-dimensional gravity in the case of g=1. For g ≥ 2, unfortunately we are not able to explicitly perform the phase space reduction of (2+1)-dimensional gravity due to the complexity of the Hamiltonian constraint equation. Based on this result, we will attempt to incorporate matter fields into (2+1)-dimensional pure gravity. The linearization and mini-superspace methods are used for this purpose. By using the linearization method, we conclude that the transverse-traceless part of the energy-momentum tensor affects the geodesic motion. In the case of the Einstein-Maxwell theory, we observe that the Wilson lines interact with the geometry to bend the geodesic motion. We analyze the mini-superspace model of (2+1)-dimensional gravity with the matter fields in the case of g=0 and g=1. For g=0, a wormhole solution is found but for g=1 we can not find an analogous solution. Quantum gravity is also considered and we succeed to perform the phase space reduction of (2+1)-dimensional gravity in the case of g=1 at the quantum level. From this analysis we argue that the conformal rotation is not necessary in the sense that the Euclidean quantum gravity is inappropriate for the full gravity. (author)
International Nuclear Information System (INIS)
Ablinger, J.; Schneider, C.; Manteuffel, A. von
2015-09-01
Three loop ladder and V-topology diagrams contributing to the massive operator matrix element A Qg are calculated. The corresponding objects can all be expressed in terms of nested sums and recurrences depending on the Mellin variable N and the dimensional parameter ε. Given these representations, the desired Laurent series expansions in ε can be obtained with the help of our computer algebra toolbox. Here we rely on generalized hypergeometric functions and Mellin-Barnes representations, on difference ring algorithms for symbolic summation, on an optimized version of the multivariate Almkvist-Zeilberger algorithm for symbolic integration, and on new methods to calculate Laurent series solutions of coupled systems of differential equations. The solutions can be computed for general coefficient matrices directly for any basis also performing the expansion in the dimensional parameter in case it is expressible in terms of indefinite nested product-sum expressions. This structural result is based on new results of our difference ring theory. In the cases discussed we deal with iterative sum- and integral-solutions over general alphabets. The final results are expressed in terms of special sums, forming quasi-shuffle algebras, such as nested harmonic sums, generalized harmonic sums, and nested binomially weighted (cyclotomic) sums. Analytic continuations to complex values of N are possible through the recursion relations obeyed by these quantities and their analytic asymptotic expansions. The latter lead to a host of new constants beyond the multiple zeta values, the infinite generalized harmonic and cyclotomic sums in the case of V-topologies.
Ablinger, J.; Behring, A.; Blümlein, J.; De Freitas, A.; von Manteuffel, A.; Schneider, C.
2016-05-01
Three loop ladder and V-topology diagrams contributing to the massive operator matrix element AQg are calculated. The corresponding objects can all be expressed in terms of nested sums and recurrences depending on the Mellin variable N and the dimensional parameter ε. Given these representations, the desired Laurent series expansions in ε can be obtained with the help of our computer algebra toolbox. Here we rely on generalized hypergeometric functions and Mellin-Barnes representations, on difference ring algorithms for symbolic summation, on an optimized version of the multivariate Almkvist-Zeilberger algorithm for symbolic integration, and on new methods to calculate Laurent series solutions of coupled systems of differential equations. The solutions can be computed for general coefficient matrices directly for any basis also performing the expansion in the dimensional parameter in case it is expressible in terms of indefinite nested product-sum expressions. This structural result is based on new results of our difference ring theory. In the cases discussed we deal with iterative sum- and integral-solutions over general alphabets. The final results are expressed in terms of special sums, forming quasi-shuffle algebras, such as nested harmonic sums, generalized harmonic sums, and nested binomially weighted (cyclotomic) sums. Analytic continuations to complex values of N are possible through the recursion relations obeyed by these quantities and their analytic asymptotic expansions. The latter lead to a host of new constants beyond the multiple zeta values, the infinite generalized harmonic and cyclotomic sums in the case of V-topologies.
Reply to ''Comment on 'Quantum massive conformal gravity' by F. F. Faria''
Energy Technology Data Exchange (ETDEWEB)
Faria, F.F. [Universidade Estadual do Piaui, Centro de Ciencias da Natureza, Teresina, PI (Brazil)
2017-01-15
Recently in (Eur Phys J C 76:341, 2016), Myung has suggested that the renormalizability of massive conformal gravity is meaningless unless the massive ghost states of the theory are stable. Here we show that massive conformal gravity can be renormalizable having unstable ghost states. (orig.)
On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity
Directory of Open Access Journals (Sweden)
Qing-Guo Huang
2015-09-01
Full Text Available In de Rham–Gabadadze–Tolley (dRGT massive gravity and bi-gravity, a non-minimal matter coupling involving both metrics generically reintroduces the Boulware–Deser (BD ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, the absence of Ostrogradski ghosts in the decoupling limit and the absence of the BD ghost from matter quantum loop corrections.
International Nuclear Information System (INIS)
Myung, Yun Soo
2010-01-01
We study graviton propagations of scalar, vector, and tensor modes in the deformed Horava-Lifshitz gravity (λR-model) without projectability condition. The quadratic Lagrangian is invariant under diffeomorphism only for λ=1 case, which contradicts to the fact that λ is irrelevant to a consistent Hamiltonian approach to the λR-model. In this case, as far as scalar propagations are concerned, there is no essential difference between deformed Horava-Lifshitz gravity (λR-model) and general relativity. This implies that there are two degrees of freedom for a massless graviton without Horava scalar, and five degrees of freedom appear for a massive graviton when introducing Lorentz-violating and Fierz-Pauli mass terms. Finally, it is shown that for λ=1, the vDVZ discontinuity is absent in the massless limit of Lorentz-violating mass terms by considering external source terms.
On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity
International Nuclear Information System (INIS)
Huang, Qing-Guo; Ribeiro, Raquel H.; Xing, Yu-Hang; Zhang, Ke-Chao; Zhou, Shuang-Yong
2015-01-01
In de Rham–Gabadadze–Tolley (dRGT) massive gravity and bi-gravity, a non-minimal matter coupling involving both metrics generically reintroduces the Boulware–Deser (BD) ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, the absence of Ostrogradski ghosts in the decoupling limit and the absence of the BD ghost from matter quantum loop corrections
Exact solution to the 'auxiliary extra-dimension' model of massive gravity
International Nuclear Information System (INIS)
Hassan, S.F.; Rosen, Rachel A.
2011-01-01
The 'auxiliary extra-dimension' model was proposed in order to provide a geometrical interpretation to modifications of general relativity, in particular to non-linear massive gravity. In this context, the theory was shown to be ghost free to third order in perturbations, in the decoupling limit. In this work, we exactly solve the equation of motion in the extra dimension, to obtain a purely 4-dimensional theory. Using this solution, it is shown that the ghost appears at the fourth order and beyond. We explore potential modifications to address the ghost issue and find that their consistent implementation requires going beyond the present framework.
Ghost free massive gravity in the Stückelberg language
International Nuclear Information System (INIS)
Rham, Claudia de; Gabadadze, Gregory; Tolley, Andrew J.
2012-01-01
Massive gravity in 4 dimensions has been shown to be free of the Boulware-Deser (BD) ghost in the ADM language for a specific choice of mass terms. We show here how this is consistent with the Stückelberg language beyond the decoupling limit, and how the constraint required to remove the BD ghost arises in this framework non-perturbatively, without the use of field redefinitions. We emphasize a subtlety in obtaining this constraint, that has been overlooked in previous literature. In both the ADM and Stückelberg formalisms the vanishing of the determinant of a Hessian guarantees the absence of the BD ghost.
Quantum analysis of Jackiw and Teitelboim's model for (1+1)D gravity and topological gauge theory
International Nuclear Information System (INIS)
Terao, Haruhiko
1993-01-01
We study the BRST quantization of the (1+1)-dimensional gravity model proposed by Jackiw and Teitelboim and also the topological gauge model which is equivalent to the gravity model at least classically. The gravity model quantized in the light-cone gauge is found to be a free theory with a nilpotent BRST charge. We show also that there exist twisted N=2 superconformal algebras in the Jackiw-Teitelboim model as well as in the topological gauge model. We discuss the quantum equivalence between the gravity theory and the topological gauge theory. It is shown that these theories are indeed equivalent to each other in the light-cone gauge. (orig.)
Is there vacuum when there is mass? Vacuum and non-vacuum solutions for massive gravity
International Nuclear Information System (INIS)
Martín-Moruno, Prado; Visser, Matt
2013-01-01
Massive gravity is a theory which has a tremendous amount of freedom to describe different cosmologies, but at the same time, the various solutions one encounters must fulfil some rather nontrivial constraints. Most of the freedom comes not from the Lagrangian, which contains only a small number of free parameters (typically three depending on counting conventions), but from the fact that one is in principle free to choose the reference metric almost arbitrarily—which effectively introduces a non-denumerable infinity of free parameters. In the current paper, we stress that although changing the reference metric would lead to a different cosmological model, this does not mean that the dynamics of the universe can be entirely divorced from its matter content. That is, while the choice of reference metric certainly influences the evolution of the physically observable foreground metric, the effect of matter cannot be neglected. Indeed the interplay between matter and geometry can be significantly changed in some specific models; effectively since the graviton would be able to curve the spacetime by itself, without the need of matter. Thus, even the set of vacuum solutions for massive gravity can have significant structure. In some cases, the effect of the reference metric could be so strong that no conceivable material content would be able to drastically affect the cosmological evolution. Dedicated to the memory of Professor Pedro F González–Díaz (paper)
Off-diagonal ekpyrotic scenarios and equivalence of modified, massive and/or Einstein gravity
Directory of Open Access Journals (Sweden)
Sergiu I. Vacaru
2016-01-01
Full Text Available Using our anholonomic frame deformation method, we show how generic off-diagonal cosmological solutions depending, in general, on all spacetime coordinates and undergoing a phase of ultra-slow contraction can be constructed in massive gravity. In this paper, there are found and studied new classes of locally anisotropic and (inhomogeneous cosmological metrics with open and closed spatial geometries. The late time acceleration is present due to effective cosmological terms induced by nonlinear off-diagonal interactions and graviton mass. The off-diagonal cosmological metrics and related Stückelberg fields are constructed in explicit form up to nonholonomic frame transforms of the Friedmann–Lamaître–Robertson–Walker (FLRW coordinates. We show that the solutions include matter, graviton mass and other effective sources modeling nonlinear gravitational and matter fields interactions in modified and/or massive gravity, with polarization of physical constants and deformations of metrics, which may explain certain dark energy and dark matter effects. There are stated and analyzed the conditions when such configurations mimic interesting solutions in general relativity and modifications and recast the general Painlevé–Gullstrand and FLRW metrics. Finally, we elaborate on a reconstruction procedure for a subclass of off-diagonal cosmological solutions which describe cyclic and ekpyrotic universes, with an emphasis on open issues and observable signatures.
Massive gravity in de Sitter space via the gravitational Higgs mechanism
International Nuclear Information System (INIS)
Iglesias, Alberto; Kakushadze, Zurab
2010-01-01
In this paper we discuss massive gravity in de Sitter space via the gravitational Higgs mechanism, which provides a nonlinear definition thereof. The Higgs scalars are described by a nonlinear sigma model, which includes higher derivative terms required to obtain the Fierz-Pauli mass term. Using the aforesaid nonperturbative definition, we address the appearance of an enhanced local symmetry and a null norm state in the linearized massive gravity in de Sitter space at the special value of the graviton mass to the Hubble parameter ratio. By studying full nonperturbative equations of motion, we argue that there is no enhanced symmetry in the full nonlinear theory. We then argue that in the full nonlinear theory no null norm state is expected to arise at the aforesaid special value. This suggests that no ghost might be present for lower graviton mass values and the full nonlinear theory might be unitary for all values of the graviton mass and the Hubble parameter with no van Dam-Veltman-Zakharov discontinuity. We argue that this is indeed the case by studying the full nonlinear Hamiltonian for the relevant conformal and helicity-0 longitudinal modes. In particular, we argue that no negative norm state is present in the full nonlinear theory.
A class of black holes in dRGT massive gravity and their thermodynamical properties
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Suchant G. [Jamia Millia Islamia, Centre of Theoretical Physics, New Delhi (India); University of Kwazulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Private Bag 54001, Durban (South Africa); Tannukij, Lunchakorn [Mahidol University, Department of Physics, Faculty of Science, Bangkok (Thailand); Wongjun, Pitayuth [Naresuan University, The Institute for Fundamental Study, Phitsanulok (Thailand); Ministry of Education, Thailand Center of Excellence in Physics, Bangkok (Thailand)
2016-03-15
We present an exact spherical black hole solution in de Rham, Gabadadze, and Tolley (dRGT) massive gravity for a generic choice of the parameters in the theory, and also discuss the thermodynamical and phase structure of the black hole in both the grand canonical and the canonical ensembles (for the charged case). It turns out that the dRGT black hole solution includes other known solutions to the Einstein field equations, such as the monopole-de Sitter-Schwarzschild solution with the coefficients of the third and fourth terms in the potential and the graviton mass in massive gravity naturally generates the cosmological constant and the global monopole term. Furthermore, we compute the mass, temperature and entropy of the dRGT black hole, and also perform thermodynamical stability analysis. It turns out that the presence of the graviton mass completely changes the black hole thermodynamics, and it can provide the Hawking-Page phase transition which also occurs for the charged black holes. Interestingly, the entropy of a black hole is barely affected and still obeys the standard area law. In particular, our results, in the limit m{sub g} → 0, reduced exactly to the results of general relativity. (orig.)
Phase transition and thermodynamic stability of topological black holes in Hořava-Lifshitz gravity
Ma, Meng-Sen; Zhao, Ren; Liu, Yan-Song
2017-08-01
On the basis of horizon thermodynamics, we study the thermodynamic stability and P-V criticality of topological black holes constructed in Hořava-Lifshitz (HL) gravity without the detailed-balance condition (with general ɛ). In the framework of horizon thermodynamics, we do not need the concrete black hole solution (the metric function) and the concrete matter fields. It is shown that the HL black hole for k=0 is always thermodynamically stable. For k=1 , the thermodynamic behaviors and P-V criticality of the HL black hole are similar to those of RN-AdS black hole for some \
Solving the strongly coupled 2D gravity III. String suspectibility and topological N-point functions
International Nuclear Information System (INIS)
Gervais, J.-L.; Roussel, J.-F.
1996-01-01
For pt.II see ibid., vol 426, p.140-86, 1994. We spell out the derivation of novel features, put forward earlier in a letter, of two-dimensional gravity in the strong coupling regime, at C L =7, 13, 19. Within the operator approach previously developed, they neatly follow from the appearance of a new cosmological term/marginal operator, different from the standard weak-coupling one, that determines the world-sheet interaction. The corresponding string susceptibility is obtained and found real contrary to the continuation of the KPZ formula. Strongly coupled (topological like) models - only involving zero-mode degrees of freedom - are solved up to sixth order, using the Ward identities which follow from the dependence upon the new cosmological constant. They are technically similar to the weakly coupled ones, which reproduce the matrix model results, but gravity and matter quantum numbers are entangled differently. (orig.)
Equations of motion for massive spin 2 field coupled to gravity
Energy Technology Data Exchange (ETDEWEB)
Buchbinder, I.L. E-mail: ilb@mail.tomsknet.ru; Gitman, D.M. E-mail: gitman@fma.if.usp.br; Krykhtin, V.A. E-mail: krykhtin@phys.dfe.tpu.edu.ru; Pershin, V.D. E-mail: pershin@ic.tsu.ru
2000-09-18
We investigate the problems of consistency and causality for the equations of motion describing massive spin two field in external gravitational and massless scalar dilaton fields in arbitrary spacetime dimension. From the field theoretical point of view we consider a general classical action with non-minimal couplings and find gravitational and dilaton background on which this action describes a theory consistent with the flat space limit. In the case of pure gravitational background all field components propagate causally. We show also that the massive spin two field can be consistently described in arbitrary background by means of the lagrangian representing an infinite series in the inverse mass. Within string theory we obtain equations of motion for the massive spin two field coupled to gravity from the requirement of quantum Weyl invariance of the corresponding two-dimensional sigma-model. In the lowest order in {alpha}' we demonstrate that these effective equations of motion coincide with consistent equations derived in field theory.
International Nuclear Information System (INIS)
Duerr, S.
2000-01-01
I give a quick summary of my proposal for simulating an improvement on quenched QCD with dynamical fermions which interact with the gluon configuration only via the topological index of the latter. It amounts to include only the topological part of the functional determinant into the measure, thereby absorbing a correction factor into the observable. I discuss the prospects of this concept from a study in the massive N f- flavour Schwinger model, where the correction factor is indeed found to be of order 0(1)
Canonical structure of BHT massive gravity in warped AdS3 sector
Directory of Open Access Journals (Sweden)
Davood Mahdavian Yekta
2016-08-01
Full Text Available We investigate the asymptotic structure of the three dimensional Warped Anti-de Sitter (WAdS3 black holes in the Bergshoeff–Hohm–Townsend (BHT massive gravity using the canonical Hamiltonian formalism. We define the canonical asymptotic gauge generators, which produce the conserved charges and the asymptotic symmetry group for the WAdS3 black holes. The attained symmetry group is described by a semi-direct sum of a Virasoro and a Kač–Moody algebra. Using the Sugawara construction, we obtain a direct sum of two Virasoro algebras. We show that not only the asymptotic conserved charges satisfy the first law of black hole thermodynamics, but also they lead to the expected Smarr formula for the WAdS3 black holes. We also show that the black hole's entropy obeys the Cardy formula of the dual conformal field theory (CFT.
Canonical structure of BHT massive gravity in warped AdS{sub 3} sector
Energy Technology Data Exchange (ETDEWEB)
Mahdavian Yekta, Davood, E-mail: d.mahdavian@hsu.ac.ir
2016-08-10
We investigate the asymptotic structure of the three dimensional Warped Anti-de Sitter (WAdS{sub 3}) black holes in the Bergshoeff–Hohm–Townsend (BHT) massive gravity using the canonical Hamiltonian formalism. We define the canonical asymptotic gauge generators, which produce the conserved charges and the asymptotic symmetry group for the WAdS{sub 3} black holes. The attained symmetry group is described by a semi-direct sum of a Virasoro and a Kač–Moody algebra. Using the Sugawara construction, we obtain a direct sum of two Virasoro algebras. We show that not only the asymptotic conserved charges satisfy the first law of black hole thermodynamics, but also they lead to the expected Smarr formula for the WAdS{sub 3} black holes. We also show that the black hole's entropy obeys the Cardy formula of the dual conformal field theory (CFT).
Massive torsion modes, chiral gravity and the Adler-Bell-Jackiw anomaly
International Nuclear Information System (INIS)
Chang, Lay Nam; Soo Chopin
2003-01-01
Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin-1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition, it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter term which is the Samuel-Jacobson-Smolin action of chiral gravity in four dimensions
Massive torsion modes, chiral gravity and the Adler-Bell-Jackiw anomaly
Energy Technology Data Exchange (ETDEWEB)
Chang, Lay Nam [Department of Physics, Virginia Tech., Blacksburg, VA 24061-0435 (United States); Soo Chopin [Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan (China)
2003-04-07
Regularization of quantum field theories introduces a mass scale which breaks axial rotational and scaling invariances. We demonstrate from first principles that axial torsion and torsion trace modes have non-transverse vacuum polarization tensors, and become massive as a result. The underlying reasons are similar to those responsible for the Adler-Bell-Jackiw (ABJ) and scaling anomalies. Since these are the only torsion components that can couple minimally to spin-1/2 particles, the anomalous generation of masses for these modes, naturally of the order of the regulator scale, may help to explain why torsion and its associated effects, including CPT violation in chiral gravity, have so far escaped detection. As a simpler manifestation of the reasons underpinning the ABJ anomaly than triangle diagrams, the vacuum polarization demonstration is also pedagogically useful. In addition, it is shown that the teleparallel limit of a Weyl fermion theory coupled only to the left-handed spin connection leads to a counter term which is the Samuel-Jacobson-Smolin action of chiral gravity in four dimensions.
Massive graviton and determination of cosmological constant from gauge theory of gravity
International Nuclear Information System (INIS)
Mitrut, Alexandru
2002-01-01
The universe contains a lot more than the eye meets . Sophisticated experiments search diligently for this invisible dark matter. Here we will describe some theoretical implications of the gravitational gauge theory recently proposed by Ning Wu (hep-th/0112062), namely the possibility of the existence of massive gravitons which fill the intergalactic space. Dark matter is an important problem in cosmology. In gravitational gauge field theory, the following effects should be taken into account to solve this problem: 1) The existence of massive graviton will have some contribution to the dark matter; 2) If the gravitational magnetic field is strong inside a celestial system, the gravitational Lorentz force will provide additional centripetal force for circular motion of a celestial object; 3) The existence of a factor which violate inverse square law of classical gravity. Combining general relativity and gravitational gauge theory the cosmological constant is determined theoretically. The cosmological constant is related to the average vacuum energy of the gravitational gauge field. Because the vacuum energy of the gravitational gauge field is negative, the cosmological constant is positive what generates repulsive force on stars to make the expansion rate of the Universe accelerated. A rough estimation of it gives out its magnitude order 10 -52 m -2 , which is well consistent with experimental results. (authors)
Supergravity and the knitting of the Kalb-Ramond two-form in eight-dimensional topological gravity
Energy Technology Data Exchange (ETDEWEB)
Baulieu, Laurent; Bellon, Marc; Tanzini, Alessandro
2003-07-17
Topological Euclidean gravity is built in eight dimensions for manifolds with Spin(7) subset of SO(8) holonomy. In a previous work, we considered the construction of an eight-dimensional topological theory describing the graviton and one graviphoton. Here we solve the question of determining a topological model for the combined system of a metric and a Kalb-Ramond two-form gauge field. We then recover the complete N=1, D=8 supergravity theory in a twisted form. We observe that the generalized self-duality conditions of our model correspond to the octonionic string equations.
Thermodynamics of the Apparent Horizon in FRW Universe with Massive Gravity
International Nuclear Information System (INIS)
Li Hui; Zhang Yi
2013-01-01
Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive gravity model in cosmology proposed lately, the corrected entropic formula of the apparent horizon is obtained with the help of the modified Friedmann equations. This entropy-area relation, together with the identified Misner-Sharp internal energy, verifies the first law of thermodynamics for the apparent horizon with a volume change term for consistency. On the other hand, by means of the corrected entropy-area formula and the Clausius relation δQ = T d S, where the heat Bow δQ is the energy-supply of pure matter projecting on the vector ξ tangent to the apparent horizon and should be looked on as the amount of energy crossing the apparent horizon during the time interval dt and the temperature of the apparent horizon for energy crossing during the same interval is 1/(2πr A ), the modified Friedmann equations governing the dynamical evolution of the universe are reproduced with the known energy density and pressure of massive graviton. The integration constant is found to correspond to a cosmological term which could be absorbed into the energy density of matter. Having established the correspondence of massive cosmology with the unified first law of thermodynamics on the apparent horizon, the validity of the generalized second law of thermodynamics is also discussed by assuming the thermal equilibrium between the apparent horizon and the matter field bounded by the apparent horizon. It is found that, in the limit H c → 0, which recovers the Minkowski reference metric solution in the fiat case, the generalized second law of thermodynamics holds if α 3 + 4α 4 3 = α 4 = 0, the generalized second law of thermodynamics could be violated. (general)
Reentrant phase transitions of higher-dimensional AdS black holes in dRGT massive gravity
International Nuclear Information System (INIS)
Zou, De-Cheng; Yue, Ruihong; Zhang, Ming
2017-01-01
We study the P-V criticality and phase transition in the extended phase space of anti-de Sitter (AdS) black holes in higher-dimensional de Rham, Gabadadze and Tolley (dRGT) massive gravity, treating the cosmological constant as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Besides the usual small/large black hole phase transitions, the interesting thermodynamic phenomena of reentrant phase transitions (RPTs) are observed for black holes in all d ≥ 6-dimensional spacetime when the coupling coefficients c_im"2 of massive potential satisfy some certain conditions. (orig.)
Reentrant phase transitions of higher-dimensional AdS black holes in dRGT massive gravity
Energy Technology Data Exchange (ETDEWEB)
Zou, De-Cheng; Yue, Ruihong [Yangzhou University, College of Physical Science and Technology, Yangzhou (China); Zhang, Ming [Xi' an Aeronautical University, Faculty of Science, Xi' an (China)
2017-04-15
We study the P-V criticality and phase transition in the extended phase space of anti-de Sitter (AdS) black holes in higher-dimensional de Rham, Gabadadze and Tolley (dRGT) massive gravity, treating the cosmological constant as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Besides the usual small/large black hole phase transitions, the interesting thermodynamic phenomena of reentrant phase transitions (RPTs) are observed for black holes in all d ≥ 6-dimensional spacetime when the coupling coefficients c{sub i}m{sup 2} of massive potential satisfy some certain conditions. (orig.)
Open FRW universes and self-acceleration from nonlinear massive gravity
International Nuclear Information System (INIS)
Gümrükçüoğlu, A. Emir; Lin, Chunshan; Mukohyama, Shinji
2011-01-01
In the context of a recently proposed nonlinear massive gravity with Lorentz-invariant mass terms, we investigate open Friedmann-Robertson-Walker (FRW) universes driven by arbitrary matter source. While the flat FRW solutions were recently shown to be absent, the proof does not extend to the open universes. We find three independent branches of solutions to the equations of motion for the Stückelberg scalars. One of the branches does not allow any nontrivial FRW cosmologies, as in the previous no-go result. On the other hand, both of the other two branches allow general open FRW universes governed by the Friedmann equation with the matter source, the standard curvature term and an effective cosmological constant Λ ± = c ± m g 2 . Here, m g is the graviton mass, + and - represent the two branches, and c ± are constants determined by the two dimensionless parameters of the theory. Since an open FRW universe with a sufficiently small curvature constant can approximate a flat FRW universe but there is no exactly flat FRW solution, the theory exhibits a discontinuity at the flat FRW limit
Asymptotically spacelike warped anti-de Sitter spacetimes in generalized minimal massive gravity
International Nuclear Information System (INIS)
Setare, M R; Adami, H
2017-01-01
In this paper we show that warped AdS 3 black hole spacetime is a solution of the generalized minimal massive gravity (GMMG) and introduce suitable boundary conditions for asymptotically warped AdS 3 spacetimes. Then we find the Killing vector fields such that transformations generated by them preserve the considered boundary conditions. We calculate the conserved charges which correspond to the obtained Killing vector fields and show that the algebra of the asymptotic conserved charges is given as the semi direct product of the Virasoro algebra with U (1) current algebra. We use a particular Sugawara construction to reconstruct the conformal algebra. Thus, we are allowed to use the Cardy formula to calculate the entropy of the warped black hole. We demonstrate that the gravitational entropy of the warped black hole exactly coincides with what we obtain via Cardy’s formula. As we expect, the warped Cardy formula also gives us exactly the same result as we obtain from the usual Cardy’s formula. We calculate mass and angular momentum of the warped black hole and then check that obtained mass, angular momentum and entropy to satisfy the first law of the black hole mechanics. According to the results of this paper we believe that the dual theory of the warped AdS 3 black hole solution of GMMG is a warped CFT. (paper)
Hocking, John G
1988-01-01
""As textbook and reference work, this is a valuable addition to the topological literature."" - Mathematical ReviewsDesigned as a text for a one-year first course in topology, this authoritative volume offers an excellent general treatment of the main ideas of topology. It includes a large number and variety of topics from classical topology as well as newer areas of research activity.There are four set-theoretic chapters, followed by four primarily algebraic chapters. Chapter I covers the fundamentals of topological and metrical spaces, mappings, compactness, product spaces, the Tychonoff t
Dadhich, Naresh; Pons, Josep M
We study static black hole solutions in Einstein and Einstein-Gauss-Bonnet gravity with the topology of the product of two spheres, [Formula: see text], in higher dimensions. There is an unusual new feature of the Gauss-Bonnet black hole: the avoidance of a non-central naked singularity prescribes a mass range for the black hole in terms of [Formula: see text]. For an Einstein-Gauss-Bonnet black hole a limited window of negative values for [Formula: see text] is also permitted. This topology encompasses black strings, branes, and generalized Nariai metrics. We also give new solutions with the product of two spheres of constant curvature.
Actions, topological terms and boundaries in first-order gravity: A review
Corichi, Alejandro; Rubalcava-García, Irais; Vukašinac, Tatjana
2016-03-01
In this review, we consider first-order gravity in four dimensions. In particular, we focus our attention in formulations where the fundamental variables are a tetrad eaI and a SO(3, 1) connection ωaIJ. We study the most general action principle compatible with diffeomorphism invariance. This implies, in particular, considering besides the standard Einstein-Hilbert-Palatini term, other terms that either do not change the equations of motion, or are topological in nature. Having a well defined action principle sometimes involves the need for additional boundary terms, whose detailed form may depend on the particular boundary conditions at hand. In this work, we consider spacetimes that include a boundary at infinity, satisfying asymptotically flat boundary conditions and/or an internal boundary satisfying isolated horizons boundary conditions. We focus on the covariant Hamiltonian formalism where the phase space Γ is given by solutions to the equations of motion. For each of the possible terms contributing to the action, we consider the well-posedness of the action, its finiteness, the contribution to the symplectic structure, and the Hamiltonian and Noether charges. For the chosen boundary conditions, standard boundary terms warrant a well posed theory. Furthermore, the boundary and topological terms do not contribute to the symplectic structure, nor the Hamiltonian conserved charges. The Noether conserved charges, on the other hand, do depend on such additional terms. The aim of this manuscript is to present a comprehensive and self-contained treatment of the subject, so the style is somewhat pedagogical. Furthermore, along the way, we point out and clarify some issues that have not been clearly understood in the literature.
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.)
AdS boundary conditions and the Topologically Massive Gravity/CFT correspondence
Skenderis, K.; Taylor, M.; van Rees, B.C.
2009-01-01
The AdS/CFT correspondence provides a new perspective on recurrent questions in General Relativity such as the allowed boundary conditions at infinity and the definition of gravitational conserved charges. Here we review the main insights obtained in this direction over the last decade and apply the
Ćaǧatay Uçgun, Filiz; Esen, Oǧul; Gümral, Hasan
2018-01-01
We present Skinner-Rusk and Hamiltonian formalisms of second order degenerate Clément and Sarıoğlu-Tekin Lagrangians. The Dirac-Bergmann constraint algorithm is employed to obtain Hamiltonian realizations of Lagrangian theories. The Gotay-Nester-Hinds algorithm is used to investigate Skinner-Rusk formalisms of these systems.
Yi, Meng; Chen, Qingkui; Xiong, Neal N
2016-11-03
This paper considers the distributed access and control problem of massive wireless sensor networks' data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.
Directory of Open Access Journals (Sweden)
Meng Yi
2016-11-01
Full Text Available This paper considers the distributed access and control problem of massive wireless sensor networks’ data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.
Wang, Juven C; Gu, Zheng-Cheng; Wen, Xiao-Gang
2015-01-23
The challenge of identifying symmetry-protected topological states (SPTs) is due to their lack of symmetry-breaking order parameters and intrinsic topological orders. For this reason, it is impossible to formulate SPTs under Ginzburg-Landau theory or probe SPTs via fractionalized bulk excitations and topology-dependent ground state degeneracy. However, the partition functions from path integrals with various symmetry twists are universal SPT invariants, fully characterizing SPTs. In this work, we use gauge fields to represent those symmetry twists in closed spacetimes of any dimensionality and arbitrary topology. This allows us to express the SPT invariants in terms of continuum field theory. We show that SPT invariants of pure gauge actions describe the SPTs predicted by group cohomology, while the mixed gauge-gravity actions describe the beyond-group-cohomology SPTs. We find new examples of mixed gauge-gravity actions for U(1) SPTs in (4+1)D via the gravitational Chern-Simons term. Field theory representations of SPT invariants not only serve as tools for classifying SPTs, but also guide us in designing physical probes for them. In addition, our field theory representations are independently powerful for studying group cohomology within the mathematical context.
Energy Technology Data Exchange (ETDEWEB)
Garbarz, Alan, E-mail: alan-at@df.uba.ar [Departamento de Física, Universidad de Buenos Aires FCEN-UBA, IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires, Argentina and Instituto de Física de La Plata, Universidad Nacional de La Plata IFLP-UNLP, C.C. 67 (Argentina); Giribet, Gaston, E-mail: gaston-at@df.uba.ar, E-mail: af.goya-at@df.uba.ar; Goya, Andrés, E-mail: gaston-at@df.uba.ar, E-mail: af.goya-at@df.uba.ar [Departamento de Física, Universidad de Buenos Aires FCEN-UBA, IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina); Leston, Mauricio, E-mail: mauricio-at@iafe.uba.ar [Instituto de Astronomía y Física del Espacio IAFE-CONICET, Ciudad Universitaria, C.C. 67 Suc. 28, 1428, Buenos Aires (Argentina)
2015-03-26
We consider critical gravity in three dimensions; that is, the New Massive Gravity theory formulated about Anti-de Sitter (AdS) space with the specific value of the graviton mass for which it results dual to a two-dimensional conformai field theory with vanishing central charge. As it happens with Kerr black holes in four-dimensional critical gravity, in three-dimensional critical gravity the Bañados-Teitelboim-Zanelli black holes have vanishing mass and vanishing angular momentum. However, provided suitable asymptotic conditions are chosen, the theory may also admit solutions carrying non-vanishing charges. Here, we give simple examples of exact solutions that exhibit falling-off conditions that are even weaker than those of the so-called Log-gravity. For such solutions, we define the quasilocal stress-tensor and use it to compute conserved charges. Despite the drastic deformation of AdS{sub 3} asymptotic, these solutions have finite mass and angular momentum, which are shown to be non-zero.
Manetti, Marco
2015-01-01
This is an introductory textbook on general and algebraic topology, aimed at anyone with a basic knowledge of calculus and linear algebra. It provides full proofs and includes many examples and exercises. The covered topics include: set theory and cardinal arithmetic; axiom of choice and Zorn's lemma; topological spaces and continuous functions; connectedness and compactness; Alexandrov compactification; quotient topologies; countability and separation axioms; prebasis and Alexander's theorem; the Tychonoff theorem and paracompactness; complete metric spaces and function spaces; Baire spaces; homotopy of maps; the fundamental group; the van Kampen theorem; covering spaces; Brouwer and Borsuk's theorems; free groups and free product of groups; and basic category theory. While it is very concrete at the beginning, abstract concepts are gradually introduced. It is suitable for anyone needing a basic, comprehensive introduction to general and algebraic topology and its applications.
Modifications of Einstein's theory of gravity at large distances
2015-01-01
In the last few years modified gravity theories have been proposed as extensions of Einstein's theory of gravity. Their main motivation is to explain the latest cosmological and astrophysical data on dark energy and dark matter. The study of general relativity at small scales has already produced important results (cf e.g. LNP 863 Quantum Gravity and Quantum Cosmology) while its study at large scales is challenging because recent and upcoming observational results will provide important information on the validity of these modified theories. In this volume, various aspects of modified gravity at large scales will be discussed: high-curvature gravity theories; general scalar-tensor theories; Galileon theories and their cosmological applications; F(R) gravity theories; massive, new massive and topologically massive gravity; Chern-Simons modifications of general relativity (including holographic variants) and higher-spin gravity theories, to name but a few of the most important recent developments. Edite...
International Nuclear Information System (INIS)
Giavarini, G.; Martin, C.P.; Ruiz Ruiz, F.
1993-01-01
We show that the renormalized vacuum expectation value of the Wilson loop for topologically massive abelian gauge theory in bbfR 3 can be defined so that its large-mass limit be the renormalized vaccum expectation value of the Wilson loop for abelian Chern-Simons theory also in bbfR 3 . (orig.)
International Nuclear Information System (INIS)
Singh, A.
1994-01-01
Recent observations of the space distribution of quasars indicate a very notable peak in space density at a redshift of 2 to 3. It is pointed out in this article that this may be the result of a phase transition which has a critical temperature of roughly a few meV (in the cosmological units h=c=k=1). It is further pointed out that such a phase transition is natural in the context of massive neutrinos. In fact, the neutrino masses required for quasar production and those required to solve the solar neutrino problem by the Mikheyev-Smirnov-Wolfenstein mechanism are consistent with each other
Do massive compact objects without event horizon exist in infinite derivative gravity?
Koshelev, Alexey S.; Mazumdar, Anupam
2017-10-01
Einstein's general theory of relativity is plagued by cosmological and black-hole type singularities Recently, it has been shown that infinite derivative, ghost free, gravity can yield nonsingular cosmological and mini-black hole solutions. In particular, the theory possesses a mass-gap determined by the scale of new physics. This paper provides a plausible argument, not a no-go theorem, based on the Area-law of gravitational entropy that within infinite derivative, ghost free, gravity nonsingular compact objects in the static limit need not have horizons.
Topology Change and the Emergence of Geometry in Two Dimensional Causal Quantum Gravity
Westra, W.
2007-01-01
Despite many attempts, gravity has vigorously resisted a unification with the laws of quantum mechanics. Besides a plethora of technical issues, one is also faced with many interesting conceptual problems. The study of quantum gravity in lower dimensional models ameliorates the technical
Marletto, C; Vedral, V
2017-12-15
All existing quantum-gravity proposals are extremely hard to test in practice. Quantum effects in the gravitational field are exceptionally small, unlike those in the electromagnetic field. The fundamental reason is that the gravitational coupling constant is about 43 orders of magnitude smaller than the fine structure constant, which governs light-matter interactions. For example, detecting gravitons-the hypothetical quanta of the gravitational field predicted by certain quantum-gravity proposals-is deemed to be practically impossible. Here we adopt a radically different, quantum-information-theoretic approach to testing quantum gravity. We propose witnessing quantumlike features in the gravitational field, by probing it with two masses each in a superposition of two locations. First, we prove that any system (e.g., a field) mediating entanglement between two quantum systems must be quantum. This argument is general and does not rely on any specific dynamics. Then, we propose an experiment to detect the entanglement generated between two masses via gravitational interaction. By our argument, the degree of entanglement between the masses is a witness of the field quantization. This experiment does not require any quantum control over gravity. It is also closer to realization than detecting gravitons or detecting quantum gravitational vacuum fluctuations.
Do massive compact objects without event horizon exist in infinite derivative gravity
Koshelev, Alexey S.; Mazumdar, Anupam
2017-01-01
Einstein’s general theory of relativity is plagued by cosmological and black-hole type singularities Recently, it has been shown that infinite derivative, ghost free, gravity can yield nonsingular cosmological and mini-black hole solutions. In particular, the theory possesses a mass-gap determined
Massive, massless and ghost modes of gravitational waves from higher-order gravity
DEFF Research Database (Denmark)
Bogdanos, Charalampos; Capozziello, Salvatore; De Laurentis, Mariafelicia
We linearize the field equations for higher order theories that contain scalar invariants other than the Ricci scalar. We find that besides a massless spin-2 field (the standard graviton), the theory contains also spin-0 and spin-2 massive modes with the latter being, in general, ghost modes. Then...
Castro \\C
2003-01-01
Moyal noncommutative star-product deformations of higher dimensional gravitational Einstein-Hilbert actions via lower-dimensional SU(\\infty) gauge theories are constructed explicitly based on the holographic reduction principle. New reparametrization invariant p-brane actions and their Moyal star product deformations follows. It is conjectured that topological Chern-Simons brane actions associated with higher-dimensional "knots" have a one-to-one correspondence with topological Chern-Simons Matrix models in the large N limit. The corresponding large N limit of Topological BF Matrix models leads to Kalb-Ramond couplings of antisymmetric-tensor fields to p-branes. The former Chern-Simons branes display higher-spin W_\\infty symmetries which are very relevant in the study of W_\\infty Gravity, the Quantum Hall effect and its higher-dimensional generalizations. We conclude by arguing why this interplay between condensed matter models, higher-dimensional extensions of the Quantum Hall effect, Chern-Simons Matrix mod...
Massive bosons interacting with gravity: No standard solutions in Robertson-Walker space-time
International Nuclear Information System (INIS)
Zecca, A.
2009-01-01
The problem of the interaction of boson and gravitational field is formulated in the Robertson-Walker space-time. It consist the simultaneous solution of the boson and of the Einstein field equation whose source is the energy momentum tensor of the boson field. By direct verification it is shown that the problem does not admit solutions in the class of massive standard solutions, previously determined, of the boson field equation. Also there cannot be solutions, in case of massive interacting boson, that are superpositions of standard solutions. The case of massless boson field is left open. The result is essentially due to the very special form of the Einstein tensor in Robertson-Walker metric.
CMB scale dependent non-Gaussianity from massive gravity during inflation
Energy Technology Data Exchange (ETDEWEB)
Domènech, Guillem; Hiramatsu, Takashi; Lin, Chunshan; Sasaki, Misao [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, 606-8502 (Japan); Shiraishi, Maresuke [Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), UTIAS, The University of Tokyo, Chiba, 277-8583 (Japan); Wang, Yi, E-mail: guillem.domenech@yukawa.kyoto-u.ac.jp, E-mail: hiramatz@yukawa.kyoto-u.ac.jp, E-mail: chunshan.lin@yukawa.kyoto-u.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp, E-mail: shiraishi-m@t.kagawa-nct.ac.jp, E-mail: phyw@ust.hk [Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)
2017-05-01
We consider a cosmological model in which the tensor mode becomes massive during inflation, and study the Cosmic Microwave Background (CMB) temperature and polarization bispectra arising from the mixing between the scalar mode and the massive tensor mode during inflation. The model assumes the existence of a preferred spatial frame during inflation. The local Lorentz invariance is already broken in cosmology due to the existence of a preferred rest frame. The existence of a preferred spatial frame further breaks the remaining local SO(3) invariance and in particular gives rise to a mass in the tensor mode. At linear perturbation level, we minimize our model so that the vector mode remains non-dynamical, while the scalar mode is the same as the one in single-field slow-roll inflation. At non-linear perturbation level, this inflationary massive graviton phase leads to a sizeable scalar-scalar-tensor coupling, much greater than the scalar-scalar-scalar one, as opposed to the conventional case. This scalar-scalar-tensor interaction imprints a scale dependent feature in the CMB temperature and polarization bispectra. Very intriguingly, we find a surprizing similarity between the predicted scale dependence and the scale-dependent non-Gaussianities at low multipoles hinted in the WMAP and Planck results.
Exact Solutions in Three-Dimensional Gravity
García-Díaz, Alberto A.
2017-09-01
Preface; 1. Introduction; 2. Point particles; 3. Dust solutions; 4. AdS cyclic symmetric stationary solutions; 5. Perfect fluid static stars; 6. Static perfect fluid stars with Λ; 7. Hydrodynamic equilibrium; 8. Stationary perfect fluid with Λ; 9. Friedmann–Robertson–Walker cosmologies; 10. Dilaton-inflaton FRW cosmologies; 11. Einstein–Maxwell solutions; 12. Nonlinear electrodynamics black hole; 13. Dilaton minimally coupled to gravity; 14. Dilaton non-minimally coupled to gravity; 15. Low energy 2+1 string gravity; 16. Topologically massive gravity; 17. Bianchi type spacetimes in TMG; 18. Petrov type N wave metrics; 19. Kundt spacetimes in TMG; 20. Cotton tensor in Riemannian spacetimes; References; Index.
Taming the cosmological constant in 2D causal quantum gravity with topology change
Loll, R.; Westra, W.; Zohren, S.
2005-01-01
As shown in previous work, there is a well-defined nonperturbative gravitational path integral including an explicit sum over topologies in the setting of Causal Dy- namical Triangulations in two dimensions. In this paper we derive a complete ana- lytical solution of the quantum continuum
A METAL-RICH LOW-GRAVITY COMPANION TO A MASSIVE MILLISECOND PULSAR
International Nuclear Information System (INIS)
Kaplan, D. L.; Bhalerao, V. B.; Van Kerkwijk, M. H.; Koester, D.; Kulkarni, S. R.; Stovall, K.
2013-01-01
Most millisecond pulsars with low-mass companions are in systems with either helium-core white dwarfs or non-degenerate (''black widow'' or ''redback'') stars. A candidate counterpart to PSR J1816+4510 was identified by Kaplan et al. whose properties were suggestive of both types of companions although identical to neither. We have assembled optical spectroscopy of the candidate companion and confirm that it is part of the binary system with a radial velocity amplitude of 343 ± 7 km s –1 , implying a high pulsar mass, M psr sin 3 i = 1.84 ± 0.11 M ☉ , and a companion mass M c sin 3 i = 0.193 ± 0.012 M ☉ , where i is the inclination of the orbit. The companion appears similar to proto-white dwarfs/sdB stars, with a gravity log 10 (g) = 4.9 ± 0.3, and effective temperature 16, 000 ± 500 K. The strongest lines in the spectrum are from hydrogen, but numerous lines from helium, calcium, silicon, and magnesium are present as well, with implied abundances of roughly 10 times solar (relative to hydrogen). As such, while from the spectrum the companion to PSR J1816+4510 is superficially most similar to a low-mass white dwarf, it has much lower gravity, is substantially larger, and shows substantial metals. Furthermore, it is able to produce ionized gas eclipses, which had previously been seen only for low-mass, non-degenerate companions in redback or black widow systems. We discuss the companion in relation to other sources, but find that we understand neither its nature nor its origins. Thus, the system is interesting for understanding unusual stellar products of binary evolution, as well as, independent of its nature, for determining neutron-star masses.
Conductivity in the gravity dual to massive ABJM and the membrane paradigm
International Nuclear Information System (INIS)
Lopez-Arcos, Cristhiam; Nastase, Horatiu; Rojas, Francisco; Murugan, Jeff
2014-01-01
In this paper we analyze the effect of the massive deformation of the ABJM model on the calculation of conductivity of the dual theory. We show that some of the difficulties presented by the dual geometry, in particular the construction of black holes therein, can be at least partially circumvented by adopting a membrane paradigm-like computation of the conductivity, which requires us to know just the effect of the deformation on the horizon of a black hole in AdS 4 . The deformation at the horizon itself is found by first deforming the flat space near the horizon, and then using the corresponding solution near the horizon as initial conditions for the Einstein’s equations. We find the same result, showing an increase in conductivity, using two types of membrane paradigm computations
New perspective for black hole thermodynamics in Gauss-Bonnet-Born-Infeld massive gravity
International Nuclear Information System (INIS)
Hendi, Seyed Hossein; Li, Gu-Qiang; Mo, Jie-Xiong; Panahiyan, Shahram; Panah, Behzad Eslam
2016-01-01
Following an earlier study regarding Einstein-Gauss-Bonnet-massive black holes in the presence of a Born-Infeld nonlinear electromagnetic field (Hendi, arXiv:1510.00108, 2016), we study thermodynamical structure and critical behavior of these black holes through various methods in this paper. Geometrical thermodynamics is employed to give a picture regarding the phase transition of these black holes. Next, a new method is used to derive critical pressure and radius of the horizon of these black holes. In addition, Maxwell equal area law is employed to study the Van der Waals like behavior of these black holes. Moreover, the critical exponents are calculated and by using Ehrenfest equations, the type of phase transition is determined. (orig.)
New perspective for black hole thermodynamics in Gauss-Bonnet-Born-Infeld massive gravity
Energy Technology Data Exchange (ETDEWEB)
Hendi, Seyed Hossein [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM),Maragha (Iran, Islamic Republic of); Li, Gu-Qiang; Mo, Jie-Xiong [Lingnan Normal University, Institute of Theoretical Physics, Zhanjiang, Guangdong (China); Panahiyan, Shahram [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Shahid Beheshti University, Physics Department, Tehran (Iran, Islamic Republic of); Panah, Behzad Eslam [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2016-10-15
Following an earlier study regarding Einstein-Gauss-Bonnet-massive black holes in the presence of a Born-Infeld nonlinear electromagnetic field (Hendi, arXiv:1510.00108, 2016), we study thermodynamical structure and critical behavior of these black holes through various methods in this paper. Geometrical thermodynamics is employed to give a picture regarding the phase transition of these black holes. Next, a new method is used to derive critical pressure and radius of the horizon of these black holes. In addition, Maxwell equal area law is employed to study the Van der Waals like behavior of these black holes. Moreover, the critical exponents are calculated and by using Ehrenfest equations, the type of phase transition is determined. (orig.)
Directory of Open Access Journals (Sweden)
Ion C. Baianu
2009-04-01
Full Text Available A novel algebraic topology approach to supersymmetry (SUSY and symmetry breaking in quantum field and quantum gravity theories is presented with a view to developing a wide range of physical applications. These include: controlled nuclear fusion and other nuclear reaction studies in quantum chromodynamics, nonlinear physics at high energy densities, dynamic Jahn-Teller effects, superfluidity, high temperature superconductors, multiple scattering by molecular systems, molecular or atomic paracrystal structures, nanomaterials, ferromagnetism in glassy materials, spin glasses, quantum phase transitions and supergravity. This approach requires a unified conceptual framework that utilizes extended symmetries and quantum groupoid, algebroid and functorial representations of non-Abelian higher dimensional structures pertinent to quantized spacetime topology and state space geometry of quantum operator algebras. Fourier transforms, generalized Fourier-Stieltjes transforms, and duality relations link, respectively, the quantum groups and quantum groupoids with their dual algebraic structures; quantum double constructions are also discussed in this context in relation to quasi-triangular, quasi-Hopf algebras, bialgebroids, Grassmann-Hopf algebras and higher dimensional algebra. On the one hand, this quantum algebraic approach is known to provide solutions to the quantum Yang-Baxter equation. On the other hand, our novel approach to extended quantum symmetries and their associated representations is shown to be relevant to locally covariant general relativity theories that are consistent with either nonlocal quantum field theories or local bosonic (spin models with the extended quantum symmetry of entangled, 'string-net condensed' (ground states.
The effective action in (2+1)-dimensional gravity and generalized BF topological field theory
Energy Technology Data Exchange (ETDEWEB)
Birmingham, D. (Theory Div., CERN, Geneva (Switzerland)); Gibbs, R.; Mokhtari, S. (Physics Dept., Louisiana Tech Univ., Ruston, LA (United States))
1991-07-11
The one-loop off-shell effective action is studied for the case of generalized BF theories in three dimensions, including, for example, (2 + 1)-dimensional gravity with a cosmological constant. The phase contribution to the effective action, originating from the {eta}-function of a particular first order operator, is calculated using a momentum space technique. It is found that the {eta}-function is proportional to the classical action. (orig.).
The effective action in (2+1)-dimensional gravity and generalized BF topological field theory
International Nuclear Information System (INIS)
Birmingham, D.; Gibbs, R.; Mokhtari, S.
1991-01-01
The one-loop off-shell effective action is studied for the case of generalized BF theories in three dimensions, including, for example, (2 + 1)-dimensional gravity with a cosmological constant. The phase contribution to the effective action, originating from the η-function of a particular first order operator, is calculated using a momentum space technique. It is found that the η-function is proportional to the classical action. (orig.)
Shear-free axial model in massive Brans–Dicke gravity
Energy Technology Data Exchange (ETDEWEB)
Sharif, M., E-mail: msharif.math@pu.edu.pk [Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590 (Pakistan); Manzoor, Rubab, E-mail: rubab.manzoor@umt.edu.pk [Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590 (Pakistan); Department of Mathematics, University of Management and Technology, Johar Town Campus, Lahore-54782 (Pakistan)
2017-01-15
This paper explores the influences of dark energy on the shear-free axially symmetric evolution by considering self-interacting Brans–Dicke gravity as a dark energy candidate. We describe energy source of the model and derive all the effective dynamical variables as well as effective structure scalars. It is found that scalar field is one of the sources of anisotropy and dissipation. The resulting effective structure scalars help to study the dynamics associated with dark energy in any axial configuration. In order to investigate shear-free evolution, we formulate a set of governing equations along with heat transport equation. We discuss consequences of shear-free condition upon different SBD fluid models like dissipative non-geodesic and geodesic models. For dissipative non-geodesic case, the rotational distribution turns out to be the necessary and sufficient condition for radiating model. The dissipation depends upon inhomogeneous expansion. The geodesic model is found to be irrotational and non-radiating. The non-dissipative geodesic model leads to FRW model for positive values of the expansion parameter.
Energy Technology Data Exchange (ETDEWEB)
Lu, Jianbo; Wu, Yabo; Wang, Yan; Yang, Weiqiang [Liaoning Normal University, Department of Physics, Dalian (China); Liu, Molin [Xinyang Normal University, Department of Physics, Xinyang (China)
2016-12-15
Tensions between several cosmic observations were found recently, such as the inconsistent values of H{sub 0} (or σ{sub 8}) were indicated by the different cosmic observations. Introducing the massive neutrinos in ΛCDM could potentially solve the tensions. Viable f(R) gravity producing ΛCDM background expansion with massive neutrinos is investigated in this paper. We fit the current observational data: Planck-2015 CMB, RSD, BAO, and SNIa to constrain the mass of neutrinos in viable f(R) theory. The constraint results at 95% confidence level are: Σm{sub ν} < 0.202 eV for the active-neutrino case, m{sub ν,sterile}{sup eff} < 0.757 eV with N{sub eff} < 3.22 for the sterile neutrino case. For the effects due to the mass of the neutrinos, the constraint results on model parameter at 95% confidence level become f{sub R0} x 10{sup -6} > -1.89 and f{sub R0} x 10{sup -6} > -2.02 for two cases, respectively. It is also shown that the fitting values of several parameters much depend on the neutrino properties, such as the cold dark matter density, the cosmological quantities at matter-radiation equality, the neutrino density and the fraction of baryonic mass in helium. Finally, the constraint result shows that the tension between direct and CMB measurements of H{sub 0} gets slightly weaker in the viable f(R) model than that in the base ΛCDM model. (orig.)
Gamow, George
2003-01-01
A distinguished physicist and teacher, George Gamow also possessed a special gift for making the intricacies of science accessible to a wide audience. In Gravity, he takes an enlightening look at three of the towering figures of science who unlocked many of the mysteries behind the laws of physics: Galileo, the first to take a close look at the process of free and restricted fall; Newton, originator of the concept of gravity as a universal force; and Einstein, who proposed that gravity is no more than the curvature of the four-dimensional space-time continuum.Graced with the author's own draw
Energy Technology Data Exchange (ETDEWEB)
Arraut, Ivan [Institute of Theoretical Physics, Chinese Academy of Science, State Key Laboratory of Theoretical Physics, Beijing (China)
2017-08-15
If we apply the path-integral formulation in order to analyze the particle creation process of black holes inside the non-linear formulation of massive gravity, it is possible to demonstrate that the effect of the extra degrees of freedom is to deform the periodicity of the poles of the propagator in the complex t-plane. This might create the effect of extra particle creation process at scales where the extra degrees of freedom become relevant. For stationary solutions, depending on the values taken by the free parameters of the theory, the periodicity structure of the propagator reveal two effects. The first one is a shift on the positions of the pole of the propagator with respect to the GR case, affecting then the instant at which the particles are detected. The second one is the existence of branch points, affecting then the perception of particles. The branch point can be finite (including the zero order case) or infinite, depending on the free parameters of the theory. (orig.)
International Nuclear Information System (INIS)
Arraut, Ivan
2017-01-01
If we apply the path-integral formulation in order to analyze the particle creation process of black holes inside the non-linear formulation of massive gravity, it is possible to demonstrate that the effect of the extra degrees of freedom is to deform the periodicity of the poles of the propagator in the complex t-plane. This might create the effect of extra particle creation process at scales where the extra degrees of freedom become relevant. For stationary solutions, depending on the values taken by the free parameters of the theory, the periodicity structure of the propagator reveal two effects. The first one is a shift on the positions of the pole of the propagator with respect to the GR case, affecting then the instant at which the particles are detected. The second one is the existence of branch points, affecting then the perception of particles. The branch point can be finite (including the zero order case) or infinite, depending on the free parameters of the theory. (orig.)
International Nuclear Information System (INIS)
Giribet, Gaston; Oliva, Julio; Tempo, David; Troncoso, Ricardo
2009-01-01
Asymptotically anti-de Sitter rotating black holes for the Bergshoeff-Hohm-Townsend massive gravity theory in three dimensions are considered. In the special case when the theory admits a unique maximally symmetric solution, apart from the mass and the angular momentum, the black hole is described by an independent 'gravitational hair' parameter, which provides a negative lower bound for the mass. This bound is saturated at the extremal case, and since the temperature and the semiclassical entropy vanish, it is naturally regarded as the ground state. The absence of a global charge associated with the gravitational hair parameter reflects itself through the first law of thermodynamics in the fact that the variation of this parameter can be consistently reabsorbed by a shift of the global charges, giving further support to consider the extremal case as the ground state. The rotating black hole fits within relaxed asymptotic conditions as compared with the ones of Brown and Henneaux, such that they are invariant under the standard asymptotic symmetries spanned by two copies of the Virasoro generators, and the algebra of the conserved charges acquires a central extension. Then it is shown that Strominger's holographic computation for general relativity can also be extended to the Bergshoeff-Hohm-Townsend theory; i.e., assuming that the quantum theory could be consistently described by a dual conformal field theory at the boundary, the black hole entropy can be microscopically computed from the asymptotic growth of the number of states according to Cardy's formula, in exact agreement with the semiclassical result.
Indian Academy of Sciences (India)
We study the cosmological dynamics for R p exp( λ R ) gravity theory in the metric formalism, using dynamical systems approach. Considering higher-dimensional FRW geometries in case of an imperfect fluid which has two different scale factors in the normal and extra dimensions, we find the exact solutions, and study its ...
pp waves of conformal gravity with self-interacting source
International Nuclear Information System (INIS)
Ayon-Beato, Eloy; Hassaine, Mokhtar
2005-01-01
Recently, Deser, Jackiw and Pi have shown that three-dimensional conformal gravity with a source given by a conformally coupled scalar field admits pp wave solutions. In this paper, we consider this model with a self-interacting potential preserving the conformal structure. A pp wave geometry is also supported by this system and, we show that this model is equivalent to topologically massive gravity with a cosmological constant whose value is given in terms of the potential strength
International Nuclear Information System (INIS)
Menezes, R.; Nascimento, J.R.S.; Ribeiro, R.F.; Wotzasek, C.
2002-01-01
We study the dual equivalence between the non-linear generalization of the self-dual (NSD BF ) and the topologically massive B and F models with particular emphasis on the non-linear electrodynamics proposed by Born and Infeld. This is done through a dynamical gauge embedding of the non-linear self-dual model yielding to a gauge invariant and dynamically equivalent theory. We clearly show that non-polinomial NSD BF models can be map, through a properly defined duality transformation into TM BF actions. The general result obtained is then particularized for a number of examples, including the Born-Infeld-BF (BIBF) model that has experienced a revival in the recent literature
No chiral truncation of quantum log gravity?
Andrade, Tomás; Marolf, Donald
2010-03-01
At the classical level, chiral gravity may be constructed as a consistent truncation of a larger theory called log gravity by requiring that left-moving charges vanish. In turn, log gravity is the limit of topologically massive gravity (TMG) at a special value of the coupling (the chiral point). We study the situation at the level of linearized quantum fields, focussing on a unitary quantization. While the TMG Hilbert space is continuous at the chiral point, the left-moving Virasoro generators become ill-defined and cannot be used to define a chiral truncation. In a sense, the left-moving asymptotic symmetries are spontaneously broken at the chiral point. In contrast, in a non-unitary quantization of TMG, both the Hilbert space and charges are continuous at the chiral point and define a unitary theory of chiral gravity at the linearized level.
Gheorghiu, Tamara; Vacaru, Sergiu I
2014-01-01
We find general parameterizations for generic off-diagonal spacetime metrics and matter sources in general relativity, GR, and modified gravity theories when the field equations decouple with respect to certain types of nonholonomic frames of reference. This allows us to construct various classes of exact solutions when the coefficients of fundamental geometric/ physical objects depend on all spacetime coordinates via corresponding classes of generating and integration functions and/or constants. Such (modified) spacetimes can be with Killing and non-Killing symmetries, describe nonlinear vacuum configurations and effective polarizations of cosmological and interaction constants. Our method can be extended to higher dimensions which simplifies some proofs for imbedded and nonholonomically constrained four dimensional configurations. We reproduce the Kerr solution and show how to deform it nonholonomically into new classes of generic off-diagonal solutions depending on 3-8 spacetime coordinates. There are anal...
Energy Technology Data Exchange (ETDEWEB)
Pitts, J. Brian, E-mail: jbp25@cam.ac.uk
2016-02-15
Einstein’s equations were derived for a free massless spin-2 field using universal coupling in the 1950–1970s by various authors; total stress–energy including gravity’s served as a source for linear free field equations. A massive variant was likewise derived in the late 1960s by Freund, Maheshwari and Schonberg, and thought to be unique. How broad is universal coupling? In the last decade four 1-parameter families of massive spin-2 theories (contravariant, covariant, tetrad, and cotetrad of almost any density weights) have been derived using universal coupling. The (co)tetrad derivations included 2 of the 3 pure spin-2 theories due to de Rham, Gabadadze, and Tolley; those two theories first appeared in the 2-parameter Ogievetsky–Polubarinov family (1965), which developed the symmetric square root of the metric as a nonlinear group realization. One of the two theories was identified as pure spin-2 by Maheshwari in 1971–1972, thus evading the Boulware–Deser–Tyutin–Fradkin ghost by the time it was announced. Unlike the previous 4 families, this paper permits nonlinear field redefinitions to build the effective metric. By not insisting in advance on knowing the observable significance of the graviton potential to all orders, one finds that an arbitrary graviton mass term can be derived using universal coupling. The arbitrariness of a universally coupled mass/self-interaction term contrasts sharply with the uniqueness of the Einstein kinetic term. One might have hoped to use universal coupling as a tie-breaking criterion for choosing among theories that are equally satisfactory on more crucial grounds (such as lacking ghosts and having a smooth massless limit). But the ubiquity of universal coupling implies that the criterion does not favor any particular theories among those with the Einstein kinetic term.
International Nuclear Information System (INIS)
Pitts, J. Brian
2016-01-01
Einstein’s equations were derived for a free massless spin-2 field using universal coupling in the 1950–1970s by various authors; total stress–energy including gravity’s served as a source for linear free field equations. A massive variant was likewise derived in the late 1960s by Freund, Maheshwari and Schonberg, and thought to be unique. How broad is universal coupling? In the last decade four 1-parameter families of massive spin-2 theories (contravariant, covariant, tetrad, and cotetrad of almost any density weights) have been derived using universal coupling. The (co)tetrad derivations included 2 of the 3 pure spin-2 theories due to de Rham, Gabadadze, and Tolley; those two theories first appeared in the 2-parameter Ogievetsky–Polubarinov family (1965), which developed the symmetric square root of the metric as a nonlinear group realization. One of the two theories was identified as pure spin-2 by Maheshwari in 1971–1972, thus evading the Boulware–Deser–Tyutin–Fradkin ghost by the time it was announced. Unlike the previous 4 families, this paper permits nonlinear field redefinitions to build the effective metric. By not insisting in advance on knowing the observable significance of the graviton potential to all orders, one finds that an arbitrary graviton mass term can be derived using universal coupling. The arbitrariness of a universally coupled mass/self-interaction term contrasts sharply with the uniqueness of the Einstein kinetic term. One might have hoped to use universal coupling as a tie-breaking criterion for choosing among theories that are equally satisfactory on more crucial grounds (such as lacking ghosts and having a smooth massless limit). But the ubiquity of universal coupling implies that the criterion does not favor any particular theories among those with the Einstein kinetic term.
Unitarity problems in 3D gravity theories
Alkac, Gokhan; Basanisi, Luca; Kilicarslan, Ercan; Tekin, Bayram
2017-07-01
We revisit the problem of the bulk-boundary unitarity clash in 2 +1 -dimensional gravity theories, which has been an obstacle in providing a viable dual two-dimensional conformal field theory for bulk gravity in anti-de Sitter (AdS) spacetime. Chiral gravity, which is a particular limit of cosmological topologically massive gravity (TMG), suffers from perturbative log-modes with negative energies inducing a nonunitary logarithmic boundary field theory. We show here that any f (R ) extension of TMG does not improve the situation. We also study the perturbative modes in the metric formulation of minimal massive gravity—originally constructed in a first-order formulation—and find that the massive mode has again negative energy except in the chiral limit. We comment on this issue and also discuss a possible solution to the problem of negative-energy modes. In any of these theories, the infinitesimal dangerous deformations might not be integrable to full solutions; this suggests a linearization instability of AdS spacetime in the direction of the perturbative log-modes.
Topological Higgs mechanism with ordinary Higgs mechanism
International Nuclear Information System (INIS)
Oda Ichiro; Yahikozawa Shigeaki.
1989-12-01
Topological Higgs mechanism in higher dimensions is analyzed when ordinary Higgs potential exists. It is shown that if one-form B-field becomes massive by the ordinary Higgs mechanism, another D-2 form C-field also becomes massive through topological term in addition to the topological mass generation by the topological Higgs mechanism. Moreover we investigate this mechanism in three dimensional theories, that is to say, Chern-Simons theory and more general theory. (author). 10 refs
Exact solutions in three-dimensional gravity
Garcia-Diaz, Alberto A
2017-01-01
A self-contained text, systematically presenting the determination and classification of exact solutions in three-dimensional Einstein gravity. This book explores the theoretical framework and general physical and geometrical characteristics of each class of solutions, and includes information on the researchers responsible for their discovery. Beginning with the physical character of the solutions, these are identified and ordered on the basis of their geometrical invariant properties, symmetries, and algebraic classifications, or from the standpoint of their physical nature, for example electrodynamic fields, fluid, scalar field, or dilaton. Consequently, this text serves as a thorough catalogue on 2+1 exact solutions to the Einstein equations coupled to matter and fields, and on vacuum solutions of topologically massive gravity with a cosmological constant. The solutions are also examined from different perspectives, enabling a conceptual bridge between exact solutions of three- and four-dimensional gravit...
Geometric flows in Horava-Lifshitz gravity
Bakas, Ioannis; Lust, Dieter; Petropoulos, Marios
2010-01-01
We consider instanton solutions of Euclidean Horava-Lifshitz gravity in four dimensions satisfying the detailed balance condition. They are described by geometric flows in three dimensions driven by certain combinations of the Cotton and Ricci tensors as well as the cosmological-constant term. The deformation curvature terms can have competing behavior leading to a variety of fixed points. The instantons interpolate between any two fixed points, which are vacua of topologically massive gravity with Lambda > 0, and their action is finite. Special emphasis is placed on configurations with SU(2) isometry associated with homogeneous but generally non-isotropic Bianchi IX model geometries. In this case, the combined Ricci-Cotton flow reduces to an autonomous system of ordinary differential equations whose properties are studied in detail for different couplings. The occurrence and stability of isotropic and anisotropic fixed points are investigated analytically and some exact solutions are obtained. The correspond...
Quantum gravity at a Lifshitz point
International Nuclear Information System (INIS)
Horava, Petr
2009-01-01
We present a candidate quantum field theory of gravity with dynamical critical exponent equal to z=3 in the UV. (As in condensed-matter systems, z measures the degree of anisotropy between space and time.) This theory, which at short distances describes interacting nonrelativistic gravitons, is power-counting renormalizable in 3+1 dimensions. When restricted to satisfy the condition of detailed balance, this theory is intimately related to topologically massive gravity in three dimensions, and the geometry of the Cotton tensor. At long distances, this theory flows naturally to the relativistic value z=1, and could therefore serve as a possible candidate for a UV completion of Einstein's general relativity or an infrared modification thereof. The effective speed of light, the Newton constant and the cosmological constant all emerge from relevant deformations of the deeply nonrelativistic z=3 theory at short distances.
Classical topology and quantum states
Indian Academy of Sciences (India)
structures) can be reconstructed using Gel'fand–Naimark theory and its ..... pair production and annihilation [23], quantum gravity too can be expected to become ..... showed their utility for research of current interest such as topology change ...
International Nuclear Information System (INIS)
Moura-Melo, Winder A.; Panza, N.; Helayel Neto, J.A.
1998-12-01
An Abelian gauge model, with vector and 2-form potential; fields linked by a topological mass term that mixes the two Abelian factors, is shown to exhibit Dirac-like magnetic monopoles in the presence of a matter background. In addition, considering a 'non-minimal coupling' between the fermions and the tensor fields, we obtain a generalized quantisation condition that involves, among others, the mass parameter. Also, it is explicitly shown that 1 loop (finite) corrections do no shift the value of such a mass parameter. (author)
Energy Technology Data Exchange (ETDEWEB)
Moura-Melo, Winder A.; Panza, N.; Helayel Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)
1998-12-01
An Abelian gauge model, with vector and 2-form potential; fields linked by a topological mass term that mixes the two Abelian factors, is shown to exhibit Dirac-like magnetic monopoles in the presence of a matter background. In addition, considering a 'non-minimal coupling' between the fermions and the tensor fields, we obtain a generalized quantisation condition that involves, among others, the mass parameter. Also, it is explicitly shown that 1{sub loop} (finite) corrections do no shift the value of such a mass parameter. (author)
Topology and geometry for physicists
Nash, Charles
1983-01-01
Differential geometry and topology are essential tools for many theoretical physicists, particularly in the study of condensed matter physics, gravity, and particle physics. Written by physicists for physics students, this text introduces geometrical and topological methods in theoretical physics and applied mathematics. It assumes no detailed background in topology or geometry, and it emphasizes physical motivations, enabling students to apply the techniques to their physics formulas and research. ""Thoroughly recommended"" by The Physics Bulletin, this volume's physics applications range fr
Energy Technology Data Exchange (ETDEWEB)
Wright, Bill S.; Winther, Hans A.; Koyama, Kazuya, E-mail: bill.wright@port.ac.uk, E-mail: hans.winther@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, Hampshire, PO1 3FX (United Kingdom)
2017-10-01
The effect of massive neutrinos on the growth of cold dark matter perturbations acts as a scale-dependent Newton's constant and leads to scale-dependent growth factors just as we often find in models of gravity beyond General Relativity. We show how to compute growth factors for ΛCDM and general modified gravity cosmologies combined with massive neutrinos in Lagrangian perturbation theory for use in COLA and extensions thereof. We implement this together with the grid-based massive neutrino method of Brandbyge and Hannestad in MG-PICOLA and compare COLA simulations to full N -body simulations of ΛCDM and f ( R ) gravity with massive neutrinos. Our implementation is computationally cheap if the underlying cosmology already has scale-dependent growth factors and it is shown to be able to produce results that match N -body to percent level accuracy for both the total and CDM matter power-spectra up to k ∼< 1 h /Mpc.
Topological superconductivity, topological confinement, and the vortex quantum Hall effect
International Nuclear Information System (INIS)
Diamantini, M. Cristina; Trugenberger, Carlo A.
2011-01-01
Topological matter is characterized by the presence of a topological BF term in its long-distance effective action. Topological defects due to the compactness of the U(1) gauge fields induce quantum phase transitions between topological insulators, topological superconductors, and topological confinement. In conventional superconductivity, because of spontaneous symmetry breaking, the photon acquires a mass due to the Anderson-Higgs mechanism. In this paper we derive the corresponding effective actions for the electromagnetic field in topological superconductors and topological confinement phases. In topological superconductors magnetic flux is confined and the photon acquires a topological mass through the BF mechanism: no symmetry breaking is involved, the ground state has topological order, and the transition is induced by quantum fluctuations. In topological confinement, instead, electric charge is linearly confined and the photon becomes a massive antisymmetric tensor via the Stueckelberg mechanism. Oblique confinement phases arise when the string condensate carries both magnetic and electric flux (dyonic strings). Such phases are characterized by a vortex quantum Hall effect potentially relevant for the dissipationless transport of information stored on vortices.
A relativistic model of the topological acceleration effect
International Nuclear Information System (INIS)
Ostrowski, Jan J; Roukema, Boudewijn F; Buliński, Zbigniew P
2012-01-01
It has previously been shown heuristically that the topology of the Universe affects gravity, in the sense that a test particle near a massive object in a multiply connected universe is subject to a topologically induced acceleration that opposes the local attraction to the massive object. It is necessary to check if this effect occurs in a fully relativistic solution of the Einstein equations that has a multiply connected spatial section. A Schwarzschild-like exact solution that is multiply connected in one spatial direction is checked for analytical and numerical consistency with the heuristic result. The T 1 (slab-space) heuristic result is found to be relativistically correct. For a fundamental domain size of L, a slow-moving, negligible-mass test particle lying at distance x along the axis from the object of mass M to its nearest multiple image, where GM/c 2 3 )x, where ζ(3) is Apery's constant. For M ∼ 10 14 M sun and L ∼ 10-20h -1 Gpc, this linear expression is accurate to ±10% over h -1 Mpc/h -1 Gpc. Thus, at least in a simple example of a multiply connected universe, the topological acceleration effect is not an artefact of Newtonian-like reasoning, and its linear derivation is accurate over about three orders of magnitude in x. (paper)
Critical gravity on AdS2 spacetimes
International Nuclear Information System (INIS)
Myung, Yun Soo; Kim, Yong-Wan; Park, Young-Jai
2011-01-01
We study the critical gravity in two-dimensional anti-de Sitter (AdS 2 ) spacetimes, which was obtained from the cosmological topologically massive gravity (TMG Λ ) in three dimensions by using the Kaluza-Klein dimensional reduction. We perform the perturbation analysis around AdS 2 , which may correspond to the near-horizon geometry of the extremal Banados, Teitelboim, and Zanelli (BTZ) black hole obtained from the TMG Λ with identification upon uplifting three dimensions. A massive propagating scalar mode δF satisfies the second-order differential equation away from the critical point of K=l, whose solution is given by the Bessel functions. On the other hand, δF satisfies the fourth-order equation at the critical point. We exactly solve the fourth-order equation, and compare it with the log gravity in two dimensions. Consequently, the critical gravity in two dimensions could not be described by a massless scalar δF ml and its logarithmic partner δF log 4th .
Massive Supergravity and Deconstruction
Gregoire, T; Shadmi, Y; Gregoire, Thomas; Schwartz, Matthew D; Shadmi, Yael
2004-01-01
We present a simple superfield Lagrangian for massive supergravity. It comprises the minimal supergravity Lagrangian with interactions as well as mass terms for the metric superfield and the chiral compensator. This is the natural generalization of the Fierz-Pauli Lagrangian for massive gravity which comprises mass terms for the metric and its trace. We show that the on-shell bosonic and fermionic fields are degenerate and have the appropriate spins: 2, 3/2, 3/2 and 1. We then study this interacting Lagrangian using goldstone superfields. We find that a chiral multiplet of goldstones gets a kinetic term through mixing, just as the scalar goldstone does in the non-supersymmetric case. This produces Planck scale (Mpl) interactions with matter and all the discontinuities and unitarity bounds associated with massive gravity. In particular, the scale of strong coupling is (Mpl m^4)^1/5, where m is the multiplet's mass. Next, we consider applications of massive supergravity to deconstruction. We estimate various qu...
Butterfly effect in 3D gravity
Qaemmaqami, Mohammad M.
2017-11-01
We study the butterfly effect by considering shock wave solutions near the horizon of the anti-de Sitter black hole in some three-dimensional gravity models including 3D Einstein gravity, minimal massive 3D gravity, new massive gravity, generalized massive gravity, Born-Infeld 3D gravity, and new bigravity. We calculate the butterfly velocities of these models and also we consider the critical points and different limits in some of these models. By studying the butterfly effect in the generalized massive gravity, we observe a correspondence between the butterfly velocities and right-left moving degrees of freedom or the central charges of the dual 2D conformal field theories.
Willard, Stephen
2004-01-01
Among the best available reference introductions to general topology, this volume is appropriate for advanced undergraduate and beginning graduate students. Its treatment encompasses two broad areas of topology: ""continuous topology,"" represented by sections on convergence, compactness, metrization and complete metric spaces, uniform spaces, and function spaces; and ""geometric topology,"" covered by nine sections on connectivity properties, topological characterization theorems, and homotopy theory. Many standard spaces are introduced in the related problems that accompany each section (340
Scalar geons in Born-Infeld gravity
Energy Technology Data Exchange (ETDEWEB)
Afonso, V.I. [Unidade Acadêmica de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB (Brazil); Olmo, Gonzalo J. [Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia—CSIC, Universidad de Valencia, Burjassot-46100, Valencia (Spain); Rubiera-Garcia, D., E-mail: viafonso@df.ufcg.edu.br, E-mail: gonzalo.olmo@uv.es, E-mail: drgarcia@fc.ul.pt [Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, Campo Grande, P-1749-016 Lisbon (Portugal)
2017-08-01
The existence of static, spherically symmetric, self-gravitating scalar field solutions in the context of Born-Infeld gravity is explored. Upon a combination of analytical approximations and numerical methods, the equations for a free scalar field (without a potential term) are solved, verifying that the solutions recover the predictions of General Relativity far from the center but finding important new effects in the central regions. We find two classes of objects depending on the ratio between the Schwarzschild radius and a length scale associated to the Born-Infeld theory: massive solutions have a wormhole structure, with their throat at r ≈ 2 M , while for the lighter configurations the topology is Euclidean. The total energy density of these solutions exhibits a solitonic profile with a maximum peaked away from the center, and located at the throat whenever a wormhole exists. The geodesic structure and curvature invariants are analyzed for the various configurations considered.
Gribov ambiguity in asymptotically AdS three-dimensional gravity
International Nuclear Information System (INIS)
Anabalon, Andres; Canfora, Fabrizio; Giacomini, Alex; Oliva, Julio
2011-01-01
In this paper the zero modes of the de Donder gauge Faddeev-Popov operator for three-dimensional gravity with negative cosmological constant are analyzed. It is found that the AdS 3 vacuum produces (infinitely many) normalizable smooth zero modes of the Faddeev-Popov operator. On the other hand, it is found that the Banados-Teitelboim-Zanelli black hole (including the zero mass black hole) does not generate zero modes. This differs from the usual Gribov problem in QCD where, close to the maximally symmetric vacuum, the Faddeev-Popov determinant is positive definite while 'far enough' from the vacuum it can vanish. This suggests that the zero mass Banados-Teitelboim-Zanelli black hole could be a suitable ground state of three-dimensional gravity with negative cosmological constant. Because of the kinematic origin of this result, it also applies for other covariant gravity theories in three dimensions with AdS 3 as maximally symmetric solution, such as new massive gravity and topologically massive gravity. The relevance of these results for supersymmetry breaking is pointed out.
On maximal massive 3D supergravity
Bergshoeff , Eric A; Hohm , Olaf; Rosseel , Jan; Townsend , Paul K
2010-01-01
ABSTRACT We construct, at the linearized level, the three-dimensional (3D) N = 4 supersymmetric " general massive supergravity " and the maximally supersymmetric N = 8 " new massive supergravity ". We also construct the maximally supersymmetric linearized N = 7 topologically massive supergravity, although we expect N = 6 to be maximal at the non-linear level. (Bergshoeff, Eric A) (Hohm, Olaf) (Rosseel, Jan) P.K.Townsend@da...
International Nuclear Information System (INIS)
Bergshoeff, E.; Ortin, T.
1998-01-01
We investigate the effective world-volume theories of branes in a background given by (the bosonic sector of) 10-dimensional massive IIA supergravity (''''massive branes'''') and their M-theoretic origin. In the case of the solitonic 5-brane of type IIA superstring theory the construction of the Wess-Zumino term in the world-volume action requires a dualization of the massive Neveu-Schwarz/Neveu-Schwarz target space 2-form field. We find that, in general, the effective world-volume theory of massive branes contains new world-volume fields that are absent in the massless case, i.e. when the mass parameter m of massive IIA supergravity is set to zero. We show how these new world-volume fields can be introduced in a systematic way. (orig.)
International Nuclear Information System (INIS)
Meszaros, A.
1984-05-01
In case the graviton has a very small non-zero mass, the existence of six additional massive gravitons with very big masses leads to a finite quantum gravity. There is an acausal behaviour on the scales that is determined by the masses of additional gravitons. (author)
Topspin networks in loop quantum gravity
International Nuclear Information System (INIS)
Duston, Christopher L
2012-01-01
We discuss the extension of loop quantum gravity to topspin networks, a proposal which allows topological information to be encoded in spin networks. We will show that this requires minimal changes to the phase space, C*-algebra and Hilbert space of cylindrical functions. We will also discuss the area and Hamiltonian operators, and show how they depend on the topology. This extends the idea of ‘background independence’ in loop quantum gravity to include topology as well as geometry. It is hoped this work will confirm the usefulness of the topspin network formalism and open up several new avenues for research into quantum gravity. (paper)
Topological insulators and topological superconductors
Bernevig, Andrei B
2013-01-01
This graduate-level textbook is the first pedagogical synthesis of the field of topological insulators and superconductors, one of the most exciting areas of research in condensed matter physics. Presenting the latest developments, while providing all the calculations necessary for a self-contained and complete description of the discipline, it is ideal for graduate students and researchers preparing to work in this area, and it will be an essential reference both within and outside the classroom. The book begins with simple concepts such as Berry phases, Dirac fermions, Hall conductance and its link to topology, and the Hofstadter problem of lattice electrons in a magnetic field. It moves on to explain topological phases of matter such as Chern insulators, two- and three-dimensional topological insulators, and Majorana p-wave wires. Additionally, the book covers zero modes on vortices in topological superconductors, time-reversal topological superconductors, and topological responses/field theory and topolo...
Nonperturbative summation over 3D discrete topologies
International Nuclear Information System (INIS)
Freidel, Laurent; Louapre, David
2003-01-01
The group field theories realizing the sum over all triangulations of all topologies of 3D discrete gravity amplitudes are known to be nonuniquely Borel summable. We modify these models to construct a new group field theory which is proved to be uniquely Borel summable, defining in an unambiguous way a nonperturbative sum over topologies in the context of 3D dynamical triangulations and spin foam models. Moreover, we give some arguments to support the fact that, despite our modification, this new model is similar to the original one, and therefore could be taken as a definition of the sum over topologies of 3D quantum gravity amplitudes
Topological Methods for Visualization
Energy Technology Data Exchange (ETDEWEB)
Berres, Anne Sabine [Los Alamos National Lab. (LANL), Los Alamos, NM (United Stat
2016-04-07
This slide presentation describes basic topological concepts, including topological spaces, homeomorphisms, homotopy, betti numbers. Scalar field topology explores finding topological features and scalar field visualization, and vector field topology explores finding topological features and vector field visualization.
Thermodynamics of quasi-topological cosmology
International Nuclear Information System (INIS)
Dehghani, M.H.; Sheykhi, A.; Dehghani, R.
2013-01-01
In this Letter, we study thermodynamical properties of the apparent horizon in a universe governed by quasi-topological gravity. Our aim is twofold. First, by using the variational method we derive the general form of Friedmann equation in quasi-topological gravity. Then, by applying the first law of thermodynamics on the apparent horizon, after using the entropy expression associated with the black hole horizon in quasi-topological gravity, and replacing the horizon radius, r + , with the apparent horizon radius, r -tilde A , we derive the corresponding Friedmann equation in quasi-topological gravity. We find that these two different approaches yield the same result which shows the profound connection between the first law of thermodynamics and the gravitational field equations of quasi-topological gravity. We also study the validity of the generalized second law of thermodynamics in quasi-topological cosmology. We find that, with the assumption of the local equilibrium hypothesis, the generalized second law of thermodynamics is fulfilled for the universe enveloped by the apparent horizon for the late time cosmology
Symmetric Space Cartan Connections and Gravity in Three and Four Dimensions
Directory of Open Access Journals (Sweden)
Derek K. Wise
2009-08-01
Full Text Available Einstein gravity in both 3 and 4 dimensions, as well as some interesting generalizations, can be written as gauge theories in which the connection is a Cartan connection for geometry modeled on a symmetric space. The relevant models in 3 dimensions include Einstein gravity in Chern-Simons form, as well as a new formulation of topologically massive gravity, with arbitrary cosmological constant, as a single constrained Chern-Simons action. In 4 dimensions the main model of interest is MacDowell-Mansouri gravity, generalized to include the Immirzi parameter in a natural way. I formulate these theories in Cartan geometric language, emphasizing also the role played by the symmetric space structure of the model. I also explain how, from the perspective of these Cartan-geometric formulations, both the topological mass in 3d and the Immirzi parameter in 4d are the result of non-simplicity of the Lorentz Lie algebra so(3,1 and its relatives. Finally, I suggest how the language of Cartan geometry provides a guiding principle for elegantly reformulating any 'gauge theory of geometry'.
Topology change and quantum physics
International Nuclear Information System (INIS)
Balachandran, A.P.; Marmo, G.; Simoni, A.
1995-01-01
The role of topology in elementary quantum physics is discussed in detail. It is argued that attributes of classical spatial topology emerge from properties of state vectors with suitably smooth time evolution. Equivalently, they emerge from considerations on the domain of the quantum Hamiltonian, this domain being often specified by boundary conditions in elementary quantum physics. Examples are presented where classical topology is changed by smoothly altering the boundary conditions. When the parameters labelling the latter are treated as quantum variables, quantum states need not give a well-defined classical topology, instead they can give a quantum superposition of such topologies. An existing argument of Sorkin based on the spin-statistics connection and indicating the necessity of topology change in quantum gravity is recalled. It is suggested therefrom and our results here that Einstein gravity and its minor variants are effective theories of a deeper description with additional novel degrees of freedom. Other reasons for suspecting such a microstructure are also summarized. (orig.)
Topology change and quantum physics
International Nuclear Information System (INIS)
Balachandran, A.P.; Marmo, G.; Simoni, A.
1995-03-01
The role of topology in elementary quantum physics is discussed in detail. It is argued that attributes of classical spatial topology emerge from properties of state vectors with suitably smooth time evolution. Equivalently, they emerge from considerations on the domain of the quantum Hamiltonian, this domain being often specified by boundary conditions in elementary quantum physics. Several examples are presented where classical topology is changed by smoothly altering the boundary conditions. When the parameters labelling the latter are treated as quantum variables, quantum states need not give a well-defined classical topology, instead they can give a quantum superposition of such topologies. An existing argument of Sorkin based on the spin-statistics connection and indicating the necessity of topology change in quantum gravity is recalled. It is suggested therefrom and our results here that Einstein gravity and its minor variants are effective theories of a deeper description with additional novel degrees of freedom. Other reasons for suspecting such a microstructure are also summarized. (author). 22 refs, 3 figs
Goodman, Sue E
2009-01-01
Beginning Topology is designed to give undergraduate students a broad notion of the scope of topology in areas of point-set, geometric, combinatorial, differential, and algebraic topology, including an introduction to knot theory. A primary goal is to expose students to some recent research and to get them actively involved in learning. Exercises and open-ended projects are placed throughout the text, making it adaptable to seminar-style classes. The book starts with a chapter introducing the basic concepts of point-set topology, with examples chosen to captivate students' imaginations while i
Topological anomalies for Seifert 3-manifolds
Energy Technology Data Exchange (ETDEWEB)
Imbimbo, Camillo [Dipartimento di Fisica, Università di Genova,Via Dodecaneso 33, 16146 Genova (Italy); INFN - Sezione di Genova,Via Dodecaneso 33, 16146, Genova (Italy); Rosa, Dario [School of Physics and Astronomy andCenter for Theoretical Physics Seoul National University,Seoul 151-747 (Korea, Republic of); Dipartimento di Fisica, Università di Milano-Bicocca,I-20126 Milano (Italy); INFN - Sezione di Milano-Bicocca,I-20126 Milano (Italy)
2015-07-14
We study globally supersymmetric 3d gauge theories on curved manifolds by describing the coupling of 3d topological gauge theories, with both Yang-Mills and Chern-Simons terms in the action, to background topological gravity. In our approach, the Seifert condition for manifolds supporting global supersymmetry is elegantly deduced from the BRST transformations of topological gravity. A cohomological characterization of the geometrical moduli which affect the partition function is obtained. In the Seifert context the Chern-Simons topological (framing) anomaly is BRST trivial. We compute explicitly the corresponding local Wess-Zumino functional. As an application, we obtain the dependence on the Seifert moduli of the partition function of 3d supersymmetric gauge theory on the squashed sphere by solving the anomalous topological Ward identities, in a regularization independent way and without the need of evaluating any functional determinant.
International Nuclear Information System (INIS)
Kogan, I.I.
1991-01-01
The quantum geometrodynamics of the open topological membrane is described in terms of 2+1 topologically massive gravity (TMG) where the inverse graviton mass is proportional to the 2D central charge and thus is the measure of the off-criticality. The hamiltonian quantization of TMG on Riemann surfaces is considered and the moduli space appears as the subspace of the quantum-mechanical configuration space containing, besides the moduli, the first-order time derivatives of half of the moduli. The appearance of the first-order time derivatives as coordinates, not momenta, is due to the third-order derivative in the TMG lagrangian. The hamiltonian for the latter leads us to the discrete levels picture which looks like the topologically massive gauge theory (TMGT) case, where we also get the Landau levels picture and the lowest Landau level corresponds to the Hilbert space of the Chern-Simons theory (CST). The connection between the positivity of the energy and the complex structure on the moduli space is discussed. (orig.)
Buchin, K.; Buchin, M.; Wagner, D.; Wattenhofer, R.
2007-01-01
Information between two nodes in a network is sent based on the network topology, the structure of links connecting pairs of nodes of a network. The task of topology control is to choose a connecting subset from all possible links such that the overall network performance is good. For instance, a
Quantum gravity from noncommutative spacetime
International Nuclear Information System (INIS)
Lee, Jungjai; Yang, Hyunseok
2014-01-01
We review a novel and authentic way to quantize gravity. This novel approach is based on the fact that Einstein gravity can be formulated in terms of a symplectic geometry rather than a Riemannian geometry in the context of emergent gravity. An essential step for emergent gravity is to realize the equivalence principle, the most important property in the theory of gravity (general relativity), from U(1) gauge theory on a symplectic or Poisson manifold. Through the realization of the equivalence principle, which is an intrinsic property in symplectic geometry known as the Darboux theorem or the Moser lemma, one can understand how diffeomorphism symmetry arises from noncommutative U(1) gauge theory; thus, gravity can emerge from the noncommutative electromagnetism, which is also an interacting theory. As a consequence, a background-independent quantum gravity in which the prior existence of any spacetime structure is not a priori assumed but is defined by using the fundamental ingredients in quantum gravity theory can be formulated. This scheme for quantum gravity can be used to resolve many notorious problems in theoretical physics, such as the cosmological constant problem, to understand the nature of dark energy, and to explain why gravity is so weak compared to other forces. In particular, it leads to a remarkable picture of what matter is. A matter field, such as leptons and quarks, simply arises as a stable localized geometry, which is a topological object in the defining algebra (noncommutative *-algebra) of quantum gravity.
Quantum gravity from noncommutative spacetime
Energy Technology Data Exchange (ETDEWEB)
Lee, Jungjai [Daejin University, Pocheon (Korea, Republic of); Yang, Hyunseok [Korea Institute for Advanced Study, Seoul (Korea, Republic of)
2014-12-15
We review a novel and authentic way to quantize gravity. This novel approach is based on the fact that Einstein gravity can be formulated in terms of a symplectic geometry rather than a Riemannian geometry in the context of emergent gravity. An essential step for emergent gravity is to realize the equivalence principle, the most important property in the theory of gravity (general relativity), from U(1) gauge theory on a symplectic or Poisson manifold. Through the realization of the equivalence principle, which is an intrinsic property in symplectic geometry known as the Darboux theorem or the Moser lemma, one can understand how diffeomorphism symmetry arises from noncommutative U(1) gauge theory; thus, gravity can emerge from the noncommutative electromagnetism, which is also an interacting theory. As a consequence, a background-independent quantum gravity in which the prior existence of any spacetime structure is not a priori assumed but is defined by using the fundamental ingredients in quantum gravity theory can be formulated. This scheme for quantum gravity can be used to resolve many notorious problems in theoretical physics, such as the cosmological constant problem, to understand the nature of dark energy, and to explain why gravity is so weak compared to other forces. In particular, it leads to a remarkable picture of what matter is. A matter field, such as leptons and quarks, simply arises as a stable localized geometry, which is a topological object in the defining algebra (noncommutative *-algebra) of quantum gravity.
Buchstaber, Victor M
2015-01-01
This book is about toric topology, a new area of mathematics that emerged at the end of the 1990s on the border of equivariant topology, algebraic and symplectic geometry, combinatorics, and commutative algebra. It has quickly grown into a very active area with many links to other areas of mathematics, and continues to attract experts from different fields. The key players in toric topology are moment-angle manifolds, a class of manifolds with torus actions defined in combinatorial terms. Construction of moment-angle manifolds relates to combinatorial geometry and algebraic geometry of toric v
Franz, Marcel
2013-01-01
Topological Insulators, volume six in the Contemporary Concepts of Condensed Matter Series, describes the recent revolution in condensed matter physics that occurred in our understanding of crystalline solids. The book chronicles the work done worldwide that led to these discoveries and provides the reader with a comprehensive overview of the field. Starting in 2004, theorists began to explore the effect of topology on the physics of band insulators, a field previously considered well understood. However, the inclusion of topology brings key new elements into this old field. Whereas it was
Yang, Zhaoju; Gao, Fei; Shi, Xihang; Lin, Xiao; Gao, Zhen; Chong, Yidong; Zhang, Baile
2015-03-01
The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life. Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia. It is thus noteworthy that an entirely novel class of electromagnetic waves, known as "topological edge states," has recently been demonstrated. These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder. Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids. The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers.
Spin foam models of matter coupled to gravity
International Nuclear Information System (INIS)
Mikovic, A
2002-01-01
We construct a class of spin foam models describing matter coupled to gravity, such that the gravitational sector is described by the unitary irreducible representations of the appropriate symmetry group, while the matter sector is described by the finite-dimensional irreducible representations of that group. The corresponding spin foam amplitudes in the four-dimensional gravity case are expressed in terms of the spin network amplitudes for pentagrams with additional external and internal matter edges. We also give a quantum field theory formulation of the model, where the matter degrees of freedom are described by spin network fields carrying the indices from the appropriate group representation. In the non-topological Lorentzian gravity case, we argue that the matter representations should be appropriate SO(3) or SO(2) representations contained in a given Lorentz matter representation, depending on whether one wants to describe a massive or a massless matter field. The corresponding spin network amplitudes are given as multiple integrals of propagators which are matrix spherical functions
Dark Matter in Quantum Gravity
Calmet, Xavier; Latosh, Boris
2018-01-01
We show that quantum gravity, whatever its ultra-violet completion might be, could account for dark matter. Indeed, besides the massless gravitational field recently observed in the form of gravitational waves, the spectrum of quantum gravity contains two massive fields respectively of spin 2 and spin 0. If these fields are long-lived, they could easily account for dark matter. In that case, dark matter would be very light and only gravitationally coupled to the standard model particles.
Superrenormalizable quantum gravity with complex ghosts
Directory of Open Access Journals (Sweden)
Leonardo Modesto
2016-04-01
Full Text Available We suggest and briefly review a new sort of superrenormalizable models of higher derivative quantum gravity. The higher derivative terms in the action can be introduced in such a way that all the unphysical massive states have complex poles. According to the literature on Lee–Wick quantization, in this case the theory can be formulated as unitary, since all massive ghosts-like degrees of freedom are unstable. Keywords: Quantum gravity, Higher derivatives, Complex poles
International Nuclear Information System (INIS)
Novello, M.; Pinto Neto, N.
1987-01-01
A theory of gravity wich considers the topological invariant I = R* α βμυ R αβμυ as one of the basic quantities to be present in the description of the dynamics of gravitational interactions is presented. A cosmical scenario induced by this theory is sketched. (Author) [pt
When Gravity Fails: Local Search Topology
Frank, Jeremy; Cheeseman, Peter; Stutz, John; Lau, Sonie (Technical Monitor)
1997-01-01
Local search algorithms for combinatorial search problems frequently encounter a sequence of states in which it is impossible to improve the value of the objective function; moves through these regions, called {\\em plateau moves), dominate the time spent in local search. We analyze and characterize {\\em plateaus) for three different classes of randomly generated Boolean Satisfiability problems. We identify several interesting features of plateaus that impact the performance of local search algorithms. We show that local minima tend to be small but occasionally may be very large. We also show that local minima can be escaped without unsatisfying a large number of clauses, but that systematically searching for an escape route may be computationally expensive if the local minimum is large. We show that plateaus with exits, called benches, tend to be much larger than minima, and that some benches have very few exit states which local search can use to escape. We show that the solutions (i.e. global minima) of randomly generated problem instances form clusters, which behave similarly to local minima. We revisit several enhancements of local search algorithms and explain their performance in light of our results. Finally we discuss strategies for creating the next generation of local search algorithms.
Luminet, Jean-Pierre
2015-08-01
Cosmic Topology is the name given to the study of the overall shape of the universe, which involves both global topological features and more local geometrical properties such as curvature. Whether space is finite or infinite, simply-connected or multi-connected like a torus, smaller or greater than the portion of the universe that we can directly observe, are questions that refer to topology rather than curvature. A striking feature of some relativistic, multi-connected "small" universe models is to create multiples images of faraway cosmic sources. While the most recent cosmological data fit the simplest model of a zero-curvature, infinite space model, they are also consistent with compact topologies of the three homogeneous and isotropic geometries of constant curvature, such as, for instance, the spherical Poincaré Dodecahedral Space, the flat hypertorus or the hyperbolic Picard horn. After a "dark age" period, the field of Cosmic Topology has recently become one of the major concerns in cosmology, not only for theorists but also for observational astronomers, leaving open a number of unsolved issues.
Schmidt, Gunther
2018-01-01
This book introduces and develops new algebraic methods to work with relations, often conceived as Boolean matrices, and applies them to topology. Although these objects mirror the matrices that appear throughout mathematics, numerics, statistics, engineering, and elsewhere, the methods used to work with them are much less well known. In addition to their purely topological applications, the volume also details how the techniques may be successfully applied to spatial reasoning and to logics of computer science. Topologists will find several familiar concepts presented in a concise and algebraically manipulable form which is far more condensed than usual, but visualized via represented relations and thus readily graspable. This approach also offers the possibility of handling topological problems using proof assistants.
DEFF Research Database (Denmark)
A. Kristensen, Anders Schmidt; Damkilde, Lars
2007-01-01
. A way to solve the initial design problem namely finding a form can be solved by so-called topology optimization. The idea is to define a design region and an amount of material. The loads and supports are also fidefined, and the algorithm finds the optimal material distribution. The objective function...... dictates the form, and the designer can choose e.g. maximum stiness, maximum allowable stresses or maximum lowest eigenfrequency. The result of the topology optimization is a relatively coarse map of material layout. This design can be transferred to a CAD system and given the necessary geometrically...... refinements, and then remeshed and reanalysed in other to secure that the design requirements are met correctly. The output of standard topology optimization has seldom well-defined, sharp contours leaving the designer with a tedious interpretation, which often results in less optimal structures. In the paper...
Arnold, Vladimir; Zorich, Anton
1999-01-01
This volume offers an account of the present state of the art in pseudoperiodic topology-a young branch of mathematics, born at the boundary between the ergodic theory of dynamical systems, topology, and number theory. Related topics include the theory of algorithms, convex integer polyhedra, Morse inequalities, real algebraic geometry, statistical physics, and algebraic number theory. The book contains many new results. Most of the articles contain brief surveys on the topics, making the volume accessible to a broad audience. From the Preface by V.I. Arnold: "The authors … have done much to s
Warner, S
1993-01-01
This text brings the reader to the frontiers of current research in topological rings. The exercises illustrate many results and theorems while a comprehensive bibliography is also included. The book is aimed at those readers acquainted with some very basic point-set topology and algebra, as normally presented in semester courses at the beginning graduate level or even at the advanced undergraduate level. Familiarity with Hausdorff, metric, compact and locally compact spaces and basic properties of continuous functions, also with groups, rings, fields, vector spaces and modules, and with Zorn''s Lemma, is also expected.
Indian Academy of Sciences (India)
tion - 6. How Architectural Features Affect. Building During Earthquakes? C VRMurty. 48 Turbulence and Dispersion. K 5 Gandhi. BOOK REVIEWS. 86 Algebraic Topology. Siddhartha Gadgil. Front Cover. - .. ..-.......... -. Back Cover. Two-dimensional vertical section through a turbulent plume. (Courtesy: G S Shat, CAOS, IISc.).
DEFF Research Database (Denmark)
Bendsøe, Martin P.; Sigmund, Ole
2007-01-01
Taking as a starting point a design case for a compliant mechanism (a force inverter), the fundamental elements of topology optimization are described. The basis for the developments is a FEM format for this design problem and emphasis is given to the parameterization of design as a raster image...
Cosmological tests of modified gravity.
Koyama, Kazuya
2016-04-01
We review recent progress in the construction of modified gravity models as alternatives to dark energy as well as the development of cosmological tests of gravity. Einstein's theory of general relativity (GR) has been tested accurately within the local universe i.e. the Solar System, but this leaves the possibility open that it is not a good description of gravity at the largest scales in the Universe. This being said, the standard model of cosmology assumes GR on all scales. In 1998, astronomers made the surprising discovery that the expansion of the Universe is accelerating, not slowing down. This late-time acceleration of the Universe has become the most challenging problem in theoretical physics. Within the framework of GR, the acceleration would originate from an unknown dark energy. Alternatively, it could be that there is no dark energy and GR itself is in error on cosmological scales. In this review, we first give an overview of recent developments in modified gravity theories including f(R) gravity, braneworld gravity, Horndeski theory and massive/bigravity theory. We then focus on common properties these models share, such as screening mechanisms they use to evade the stringent Solar System tests. Once armed with a theoretical knowledge of modified gravity models, we move on to discuss how we can test modifications of gravity on cosmological scales. We present tests of gravity using linear cosmological perturbations and review the latest constraints on deviations from the standard [Formula: see text]CDM model. Since screening mechanisms leave distinct signatures in the non-linear structure formation, we also review novel astrophysical tests of gravity using clusters, dwarf galaxies and stars. The last decade has seen a number of new constraints placed on gravity from astrophysical to cosmological scales. Thanks to on-going and future surveys, cosmological tests of gravity will enjoy another, possibly even more, exciting ten years.
On massive gravitons in 2+1 dimensions
Bergshoeff, Eric; Hohm, Olaf; Townsend, Paul; Lazkoz, R; Vera, R
2010-01-01
The Fierz-Pauli (FP) free field theory for massive spin-2 particles can be extended, in a spacetime of (1+2) dimensions (3D), to a generally covariant parity-preserving interacting field theory, in at least two ways. One is "new massive gravity" (NMG), with an action that involves curvature-squared
Fomenko, Anatoly
2016-01-01
This classic text of the renowned Moscow mathematical school equips the aspiring mathematician with a solid grounding in the core of topology, from a homotopical perspective. Its comprehensiveness and depth of treatment are unmatched among topology textbooks: in addition to covering the basics—the fundamental notions and constructions of homotopy theory, covering spaces and the fundamental group, CW complexes, homology and cohomology, homological algebra—the book treats essential advanced topics, such as obstruction theory, characteristic classes, Steenrod squares, K-theory and cobordism theory, and, with distinctive thoroughness and lucidity, spectral sequences. The organization of the material around the major achievements of the golden era of topology—the Adams conjecture, Bott periodicity, the Hirzebruch–Riemann–Roch theorem, the Atiyah–Singer index theorem, to name a few—paints a clear picture of the canon of the subject. Grassmannians, loop spaces, and classical groups play a central role ...
International Nuclear Information System (INIS)
Hartle, J.B.
1985-01-01
Simplicial approximation and the ideas associated with the Regge calculus provide a concrete way of implementing a sum over histories formulation of quantum gravity. A simplicial geometry is made up of flat simplices joined together in a prescribed way together with an assignment of lengths to their edges. A sum over simplicial geometries is a sum over the different ways the simplices can be joined together with an integral over their edge lengths. The construction of the simplicial Euclidean action for this approach to quantum general relativity is illustrated. The recovery of the diffeomorphism group in the continuum limit is discussed. Some possible classes of simplicial complexes with which to define a sum over topologies are described. In two dimensional quantum gravity it is argued that a reasonable class is the class of pseudomanifolds
Strings reinterpreted as topological elements of space time
International Nuclear Information System (INIS)
Ne'eman, Y.
1986-01-01
In 1974, Scherk and Schwarz suggested a reinterpretation of string dynamics as a theory of quantum gravity with unification. We suggest completing the transition through the reinterpretation of the strings themselves as Feynman-paths, spanning the topology of space time in the Hawking-King-McCarthy model. This explains the emergency of gravity
Trees and spatial topology change in CDT
DEFF Research Database (Denmark)
Ambjorn, Jan; Budd, Timothy George
2013-01-01
Generalized causal dynamical triangulations (generalized CDT) is a model of two-dimensional quantum gravity in which a limited number of spatial topology changes is allowed to occur. We solve the model at the discretized level using bijections between quadrangulations and trees. In the continuum...
Quasinormal modes for massless topological black holes
International Nuclear Information System (INIS)
Aros, Rodrigo; Martinez, Cristian; Troncoso, Ricardo; Zanelli, Jorge
2003-01-01
An exact expression for the quasinormal modes of scalar perturbation on a massless topological black hole in four and higher dimensions is presented. The massive scalar field is nonminimally coupled to the curvature, and the horizon geometry is assumed to have a negative constant curvature
Topological Aspects of Information Retrieval.
Egghe, Leo; Rousseau, Ronald
1998-01-01
Discusses topological aspects of theoretical information retrieval, including retrieval topology; similarity topology; pseudo-metric topology; document spaces as topological spaces; Boolean information retrieval as a subsystem of any topological system; and proofs of theorems. (LRW)
Guillemin, Victor
2010-01-01
Differential Topology provides an elementary and intuitive introduction to the study of smooth manifolds. In the years since its first publication, Guillemin and Pollack's book has become a standard text on the subject. It is a jewel of mathematical exposition, judiciously picking exactly the right mixture of detail and generality to display the richness within. The text is mostly self-contained, requiring only undergraduate analysis and linear algebra. By relying on a unifying idea-transversality-the authors are able to avoid the use of big machinery or ad hoc techniques to establish the main
Turning on gravity with the Higgs mechanism
International Nuclear Information System (INIS)
Alexander, Stephon; Barrow, John D; Magueijo, João
2016-01-01
We investigate how a Higgs mechanism could be responsible for the emergence of gravity in extensions of Einstein theory, with a suitable low energy limit. In this scenario, at high energies, symmetry restoration could ‘turn off’ gravity, with dramatic implications for cosmology and quantum gravity. The sense in which gravity is muted depends on the details of the implementation. In the most extreme case gravity’s dynamical degrees of freedom would only be unleashed after the Higgs field acquires a non-trivial vacuum expectation value, with gravity reduced to a topological field theory in the symmetric phase. We might also identify the Higgs and the Brans–Dicke fields in such a way that in the unbroken phase Newton’s constant vanishes, decoupling matter and gravity. We discuss the broad implications of these scenarios. (letter)
Topological quantization of gravitational fields
International Nuclear Information System (INIS)
Patino, Leonardo; Quevedo, Hernando
2005-01-01
We introduce the method of topological quantization for gravitational fields in a systematic manner. First we show that any vacuum solution of Einstein's equations can be represented in a principal fiber bundle with a connection that takes values in the Lie algebra of the Lorentz group. This result is generalized to include the case of gauge matter fields in multiple principal fiber bundles. We present several examples of gravitational configurations that include a gravitomagnetic monopole in linearized gravity, the C-energy of cylindrically symmetric fields, the Reissner-Nordstroem and the Kerr-Newman black holes. As a result of the application of the topological quantization procedure, in all the analyzed examples we obtain conditions implying that the parameters entering the metric in each case satisfy certain discretization relationships
Mashhoon, Bahram
2017-01-01
Relativity theory is based on a postulate of locality, which means that the past history of the observer is not directly taken into account. This book argues that the past history should be taken into account. In this way, nonlocality---in the sense of history dependence---is introduced into relativity theory. The deep connection between inertia and gravitation suggests that gravity could be nonlocal, and in nonlocal gravity the fading gravitational memory of past events must then be taken into account. Along this line of thought, a classical nonlocal generalization of Einstein's theory of gravitation has recently been developed. A significant consequence of this theory is that the nonlocal aspect of gravity appears to simulate dark matter. According to nonlocal gravity theory, what astronomers attribute to dark matter should instead be due to the nonlocality of gravitation. Nonlocality dominates on the scale of galaxies and beyond. Memory fades with time; therefore, the nonlocal aspect of gravity becomes wea...
Topology of classical vacuum space-time
International Nuclear Information System (INIS)
Cho, Y.M.
2007-04-01
We present a topological classification of classical vacuum space-time. Assuming the 3-dimensional space allows a global chart, we show that the static vacuum space-time of Einstein's theory can be classified by the knot topology π 3 (S 3 ) = π 3 (S 2 ). Viewing Einstein's theory as a gauge theory of Lorentz group and identifying the gravitational connection as the gauge potential of Lorentz group, we construct all possible vacuum gravitational connections which give a vanishing curvature tensor. With this we show that the vacuum connection has the knot topology, the same topology which describes the multiple vacua of SU(2) gauge theory. We discuss the physical implications of our result in quantum gravity. (author)
Topological methods in gauge theory
International Nuclear Information System (INIS)
Sarukkai, S.R.
1992-01-01
The author begins with an overview of the important topological methods used in gauge theory. In the first chapter, the author discusses the general structure of fiber bundles and associated mathematical concepts and briefly discuss their application in gauge theory. The second chapter deals with the study of instantons in both gauge and gravity theories. These self-dual solutions are presented. This chapter is also a broad introduction to certain topics in gravitational physics. Gravity and gauge theory are unified in Kaluza-Klein theory as discussed in the third chapter. Of particular interest is the physics of the U(1) bundles over non-trivial manifolds. The radius of the fifth dimension is undetermined classically in the Kaluza-Klein theory. A mechanism is described using topological information to derive the functional form of the radius of the fifth dimension and show that it is possible classically to derive expressions for the radius as a consequence of topology. The behavior of the radius is dependent on the information present in the base metric. Results are computed for three gravitational instantons. Consequences of this mechanism are discussed. The description is studied of instantons in terms of projector valued fields and universal bundles. The results of the previous chapter and this are connected via the study of universal bundles. Projector valued transformations are defined and their consequences discussed. With the solutions of instantons in this formalism, it is shown explicitly that there can be solutions which allow for a Sp(n) instanton to be transformed to a Sp(k) instanton, thus showing that there can be interpolations which carry one instanton with a rank n to another characterized by rank k with different topological numbers
The topology of moduli space and quantum field theory
International Nuclear Information System (INIS)
Montano, D.; Sonnenschein, J.
1989-01-01
We show how an SO(2,1) gauge theory with a fermionic symmetry may be used to describe the topology of the moduli space of curves. The observables of the theory correspond to the generators of the cohomology of moduli space. This is an extension of the topological quantum field theory introduced by Witten to investigate the cohomology of Yang-Mills instanton moduli space. We explore the basic structure of topological quantum field theories, examine a toy U(1) model, and then realize a full theory of moduli space topology. We also discuss why a pure gravity theory, as attempted in previous work, could not succeed. (orig.)
Emerging Trends in Topological Insulators and Topological ...
Indian Academy of Sciences (India)
/fulltext/reso/022/08/0787-0800. Keywords. Superconductor, quantum Hall effect, topological insulator, Majorana fermions. Abstract. Topological insulators are new class of materials which arecharacterized by a bulk band gap like ordinary ...
Margalef-Roig, J
1992-01-01
...there are reasons enough to warrant a coherent treatment of the main body of differential topology in the realm of Banach manifolds, which is at the same time correct and complete. This book fills the gap: whenever possible the manifolds treated are Banach manifolds with corners. Corners add to the complications and the authors have carefully fathomed the validity of all main results at corners. Even in finite dimensions some results at corners are more complete and better thought out here than elsewhere in the literature. The proofs are correct and with all details. I see this book as a reliable monograph of a well-defined subject; the possibility to fall back to it adds to the feeling of security when climbing in the more dangerous realms of infinite dimensional differential geometry. Peter W. Michor
Surfaces and slabs of fractional topological insulator heterostructures
Sahoo, Sharmistha; Sirota, Alexander; Cho, Gil Young; Teo, Jeffrey C. Y.
2017-10-01
Fractional topological insulators (FTIs) are electronic topological phases in (3 +1 ) dimensions enriched by time reversal (TR) and charge U (1 ) conservation symmetries. We focus on the simplest series of fermionic FTIs, whose bulk quasiparticles consist of deconfined partons that carry fractional electric charges in integral units of e*=e /(2 n +1 ) and couple to a discrete Z2 n +1 gauge theory. We propose massive symmetry preserving or breaking FTI surface states. Combining the long-ranged entangled bulk with these topological surface states, we deduce the novel topological order of quasi-(2 +1 ) -dimensional FTI slabs as well as their corresponding edge conformal field theories.
Quintessential quartic quasi-topological quartet
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Jamil [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Department of Mathematics, Quaid-i-Azam University,Islamabad (Pakistan); Hennigar, Robie A. [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Mann, Robert B. [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Mir, Mozhgan [Department of Physics and Astronomy, University of Waterloo,200 University Avenue West, Waterloo, ON, N2L 3G1 (Canada); School of Physics, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
2017-05-25
We construct the quartic version of generalized quasi-topological gravity, which was recently constructed to cubic order in https://arxiv.org/abs/1703.01631. This class of theories includes Lovelock gravity and a known form of quartic quasi-topological gravity as special cases and possess a number of remarkable properties: (i) In vacuum, or in the presence of suitable matter, there is a single independent field equation which is a total derivative. (ii) At the linearized level, the equations of motion on a maximally symmetric background are second order, coinciding with the linearized Einstein equations up to a redefinition of Newton’s constant. Therefore, these theories propagate only the massless, transverse graviton on a maximally symmetric background. (iii) While the Lovelock and quasi-topological terms are trivial in four dimensions, there exist four new generalized quasi-topological terms (the quartet) that are nontrivial, leading to interesting higher curvature theories in d≥4 dimensions that appear well suited for holographic study. We construct four dimensional black hole solutions to the theory and study their properties. A study of black brane solutions in arbitrary dimensions reveals that these solutions are modified from the ‘universal’ properties they possess in other higher curvature theories, which may lead to interesting consequences for the dual CFTs.
Massive Schwinger model at finite θ
Azcoiti, Vicente; Follana, Eduardo; Royo-Amondarain, Eduardo; Di Carlo, Giuseppe; Vaquero Avilés-Casco, Alejandro
2018-01-01
Using the approach developed by V. Azcoiti et al. [Phys. Lett. B 563, 117 (2003), 10.1016/S0370-2693(03)00601-4], we are able to reconstruct the behavior of the massive one-flavor Schwinger model with a θ term and a quantized topological charge. We calculate the full dependence of the order parameter with θ . Our results at θ =π are compatible with Coleman's conjecture on the phase diagram of this model.
Induced topological pressure for topological dynamical systems
International Nuclear Information System (INIS)
Xing, Zhitao; Chen, Ercai
2015-01-01
In this paper, inspired by the article [J. Jaerisch et al., Stochastics Dyn. 14, 1350016, pp. 1-30 (2014)], we introduce the induced topological pressure for a topological dynamical system. In particular, we prove a variational principle for the induced topological pressure
Lujan, Richard E.
2001-01-01
A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.
Directory of Open Access Journals (Sweden)
Barceló Carlos
2005-12-01
Full Text Available Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.
2D gravity and random matrices
International Nuclear Information System (INIS)
Zinn-Justin, J.
1990-01-01
Recent progress in 2D gravity coupled to d ≤ 1 matter, based on a representation of discrete gravity in terms of random matrices, is reported. The matrix problem can be solved in many cases by the introduction of suitable orthogonal polynomials. Alternatively in the continuum limit the orthogonal polynomial method can be shown to be equivalent to the construction of representation of the canonical commutation relations in terms of differential operators. In the case of pure gravity or discrete Ising-like matter the sum over topologies is reduced to the solution of non-linear differential equations. The d = 1 problem can be solved by semiclassical methods
Alvarez, Enrique
2004-01-01
Gravitons should have momentum just as photons do; and since graviton momentum would cause compression rather than elongation of spacetime outside of matter; it does not appear that gravitons are compatible with Swartzchild's spacetime curvature. Also, since energy is proportional to mass, and mass is proportional to gravity; the energy of matter is proportional to gravity. The energy of matter could thus contract space within matter; and because of the inter-connectedness of space, cause the...
Energy Technology Data Exchange (ETDEWEB)
Lamon, Raphael
2010-06-29
Quantum gravity is an attempt to unify general relativity with quantum mechanics which are the two highly successful fundamental theories of theoretical physics. The main difficulty in this unification arises from the fact that, while general relativity describes gravity as a macroscopic geometrical theory, quantum mechanics explains microscopic phenomena. As a further complication, not only do both theories describe different scales but also their philosophical ramifications and the mathematics used to describe them differ in a dramatic way. Consequently, one possible starting point of an attempt at a unification is quantum mechanics, i.e. particle physics, and try to incorporate gravitation. This pathway has been chosen by particle physicists which led to string theory. On the other hand, loop quantum gravity (LQG) chooses the other possibility, i.e. it takes the geometrical aspects of gravity seriously and quantizes geometry. The first part of this thesis deals with a generalization of loop quantum cosmology (LQC) to toroidal topologies. LQC is a quantization of homogenous solutions of Einstein's field equations using tools from LQG. First the general concepts of closed topologies is introduced with special emphasis on Thurston's theorem and its consequences. It is shown that new degrees of freedom called Teichmueller parameters come into play and their dynamics can be described by a Hamiltonian. Several numerical solutions for a toroidal universe are presented and discussed. Following the guidelines of LQG this dynamics are rewritten using the Ashtekar variables and numerical solutions are shown. However, in order to find a suitable Hilbert space a canonical transformation must be performed. On the other hand this transformation makes the quantization of geometrical quantities less tractable such that two different ways are presented. It is shown that in both cases the spectrum of such geometrical operators depends on the initial value problem
International Nuclear Information System (INIS)
Lamon, Raphael
2010-01-01
Quantum gravity is an attempt to unify general relativity with quantum mechanics which are the two highly successful fundamental theories of theoretical physics. The main difficulty in this unification arises from the fact that, while general relativity describes gravity as a macroscopic geometrical theory, quantum mechanics explains microscopic phenomena. As a further complication, not only do both theories describe different scales but also their philosophical ramifications and the mathematics used to describe them differ in a dramatic way. Consequently, one possible starting point of an attempt at a unification is quantum mechanics, i.e. particle physics, and try to incorporate gravitation. This pathway has been chosen by particle physicists which led to string theory. On the other hand, loop quantum gravity (LQG) chooses the other possibility, i.e. it takes the geometrical aspects of gravity seriously and quantizes geometry. The first part of this thesis deals with a generalization of loop quantum cosmology (LQC) to toroidal topologies. LQC is a quantization of homogenous solutions of Einstein's field equations using tools from LQG. First the general concepts of closed topologies is introduced with special emphasis on Thurston's theorem and its consequences. It is shown that new degrees of freedom called Teichmueller parameters come into play and their dynamics can be described by a Hamiltonian. Several numerical solutions for a toroidal universe are presented and discussed. Following the guidelines of LQG this dynamics are rewritten using the Ashtekar variables and numerical solutions are shown. However, in order to find a suitable Hilbert space a canonical transformation must be performed. On the other hand this transformation makes the quantization of geometrical quantities less tractable such that two different ways are presented. It is shown that in both cases the spectrum of such geometrical operators depends on the initial value problem. Furthermore, we
Superrenormalizable quantum gravity with complex ghosts
Energy Technology Data Exchange (ETDEWEB)
Modesto, Leonardo, E-mail: lmodesto@fudan.edu.cn [Department of Physics & Center for Field Theory and Particle Physics, Fudan University, 200433, Shanghai (China); Shapiro, Ilya L., E-mail: shapiro@fisica.ufjf.br [Departamento de Fisica – ICE, Universidade Federal de Juiz de Fora, 33036-900 Juiz de Fora, Minas Gerais (Brazil); Tomsk State Pedagogical University and Tomsk State University, 634041, Tomsk (Russian Federation)
2016-04-10
We suggest and briefly review a new sort of superrenormalizable models of higher derivative quantum gravity. The higher derivative terms in the action can be introduced in such a way that all the unphysical massive states have complex poles. According to the literature on Lee–Wick quantization, in this case the theory can be formulated as unitary, since all massive ghosts-like degrees of freedom are unstable.
DEFF Research Database (Denmark)
Marcussen, Lars
2003-01-01
Rummets topologi, Historiens topologi: betragtninger om menneskets orientering til rum - fra hulen over beherskelse af flere akser til det flydende rum.......Rummets topologi, Historiens topologi: betragtninger om menneskets orientering til rum - fra hulen over beherskelse af flere akser til det flydende rum....
Dual descriptions of spin-two massive particles in D=2+1 via master actions
Dalmazi, D.; Mendonça, Elias L.
2009-02-01
In the first part of this work we show the decoupling (up to contact terms) of redundant degrees of freedom which appear in the covariant description of spin-two massive particles in D=2+1. We make use of a master action which interpolates, without solving any constraints, between a first-, second-, and third-order (in derivatives) self-dual model. An explicit dual map between those models is derived. In our approach the absence of ghosts in the third-order self-dual model, which corresponds to a quadratic truncation of topologically massive gravity, is due to the triviality (no particle content) of the Einstein-Hilbert action in D=2+1. In the second part of the work, also in D=2+1, we prove the quantum equivalence of the gauge invariant sector of a couple of self-dual models of opposite helicities (+2 and -2) and masses m+ and m- to a generalized self-dual model which contains a quadratic Einstein-Hilbert action, a Chern-Simons term of first order, and a Fierz-Pauli mass term. The use of a first-order Chern-Simons term instead of a third-order one avoids conflicts with the sign of the Einstein-Hilbert action.
Dual descriptions of spin-two massive particles in D=2+1 via master actions
International Nuclear Information System (INIS)
Dalmazi, D.; Mendonca, Elias L.
2009-01-01
In the first part of this work we show the decoupling (up to contact terms) of redundant degrees of freedom which appear in the covariant description of spin-two massive particles in D=2+1. We make use of a master action which interpolates, without solving any constraints, between a first-, second-, and third-order (in derivatives) self-dual model. An explicit dual map between those models is derived. In our approach the absence of ghosts in the third-order self-dual model, which corresponds to a quadratic truncation of topologically massive gravity, is due to the triviality (no particle content) of the Einstein-Hilbert action in D=2+1. In the second part of the work, also in D=2+1, we prove the quantum equivalence of the gauge invariant sector of a couple of self-dual models of opposite helicities (+2 and -2) and masses m + and m - to a generalized self-dual model which contains a quadratic Einstein-Hilbert action, a Chern-Simons term of first order, and a Fierz-Pauli mass term. The use of a first-order Chern-Simons term instead of a third-order one avoids conflicts with the sign of the Einstein-Hilbert action.
Formation of Massive Molecular Cloud Cores by Cloud-cloud Collision
Inoue, Tsuyoshi; Fukui, Yasuo
2013-01-01
Recent observations of molecular clouds around rich massive star clusters including NGC3603, Westerlund 2, and M20 revealed that the formation of massive stars could be triggered by a cloud-cloud collision. By using three-dimensional, isothermal, magnetohydrodynamics simulations with the effect of self-gravity, we demonstrate that massive, gravitationally unstable, molecular cloud cores are formed behind the strong shock waves induced by the cloud-cloud collision. We find that the massive mol...
Topological superconductors: a review.
Sato, Masatoshi; Ando, Yoichi
2017-07-01
This review elaborates pedagogically on the fundamental concept, basic theory, expected properties, and materials realizations of topological superconductors. The relation between topological superconductivity and Majorana fermions are explained, and the difference between dispersive Majorana fermions and a localized Majorana zero mode is emphasized. A variety of routes to topological superconductivity are explained with an emphasis on the roles of spin-orbit coupling. Present experimental situations and possible signatures of topological superconductivity are summarized with an emphasis on intrinsic topological superconductors.
Gamelin, Theodore W
1999-01-01
A fresh approach to introductory topology, this volume explains nontrivial applications of metric space topology to analysis, clearly establishing their relationship. Also, topics from elementary algebraic topology focus on concrete results with minimal algebraic formalism. The first two chapters consider metric space and point-set topology; the second two, algebraic topological material. 1983 edition. Solutions to Selected Exercises. List of Notations. Index. 51 illustrations.
Cosmological viability of theories with massive spin-2 fields
Energy Technology Data Exchange (ETDEWEB)
Koennig, Frank
2017-03-30
Theories of spin-2 fields take on a particular role in modern physics. They do not only describe the mediation of gravity, the only theory of fundamental interactions of which no quantum field theoretical description exists, it furthermore was thought that they necessarily predict massless gauge bosons. Just recently, a consistent theory of a massive graviton was constructed and, subsequently, generalized to a bimetric theory of two interacting spin-2 fields. This thesis studies both the viability and consequences at cosmological scales in massive gravity as well as bimetric theories. We show that all consistent models that are free of gradient and ghost instabilities behave like the cosmological standard model, LCDM. In addition, we construct a new theory of massive gravity which is stable at both classical background and quantum level, even though it suffers from the Boulware-Deser ghost.
Thermodynamical Study of FRW Universe in Quasi-Topological Theory
Directory of Open Access Journals (Sweden)
H. Moradpour
2016-01-01
Full Text Available By applying the unified first law of thermodynamics on the apparent horizon of FRW universe, we get the entropy relation for the apparent horizon in quasi-topological gravity theory. Throughout the paper, the results of considering the Hayward-Kodama and Cai-Kim temperatures are also addressed. Our study shows that whenever there is no energy exchange between the various parts of cosmos, we can get an expression for the apparent horizon entropy in quasi-topological gravity, which is in agreement with other attempts that followed different approaches. The effects of a mutual interaction between the various parts of cosmos on the apparent horizon entropy as well as the validity of second law of thermodynamics in quasi-topological gravity are perused.
Directory of Open Access Journals (Sweden)
Carlos Barceló
2011-05-01
Full Text Available Analogue gravity is a research programme which investigates analogues of general relativistic gravitational fields within other physical systems, typically but not exclusively condensed matter systems, with the aim of gaining new insights into their corresponding problems. Analogue models of (and for gravity have a long and distinguished history dating back to the earliest years of general relativity. In this review article we will discuss the history, aims, results, and future prospects for the various analogue models. We start the discussion by presenting a particularly simple example of an analogue model, before exploring the rich history and complex tapestry of models discussed in the literature. The last decade in particular has seen a remarkable and sustained development of analogue gravity ideas, leading to some hundreds of published articles, a workshop, two books, and this review article. Future prospects for the analogue gravity programme also look promising, both on the experimental front (where technology is rapidly advancing and on the theoretical front (where variants of analogue models can be used as a springboard for radical attacks on the problem of quantum gravity.
Is quantum gravity unpredictable
International Nuclear Information System (INIS)
Gross, D.J.
1984-01-01
An investigation of Hawking's proposal that the inclusion of topologically non-trivial manifolds in the functional integral of quantum gravity leads to the loss of quantum coherence is carried out. We discuss some of the problems associated with Hawking's Dollar-matrix theory, including the breakdown of the connection between symmetry principles and conservation laws. It is proposed to use Kaluza-Klein theories to study this issue, since these theories contain well-defined euclidean instantons. These can be used to perform explicit semiclassical calculations of the effects of space-time foam. A general method is presented for constructing Kaluza-Klein instantons based on solutions of ordinary Yang-Mills theory. It is argued that none of these will lead to a breakdown of quantum mechanics. The physical effects of space-time foam are discussed in some detail using explicit instantons of a four-dimensional Kaluza-Klein theory. (orig.)
Spin foam diagrammatics and topological invariance
International Nuclear Information System (INIS)
Girelli, Florian; Oeckl, Robert; Perez, Alejandro
2002-01-01
We provide a simple proof of the topological invariance of the Turaev-Viro model (corresponding to simplicial 3D pure Euclidean gravity with cosmological constant) by means of a novel diagrammatic formulation of the state sum models for quantum BF theories. Moreover, we prove the invariance under more general conditions allowing the state sum to be defined on arbitrary cellular decompositions of the underlying manifold. Invariance is governed by a set of identities corresponding to local gluing and rearrangement of cells in the complex. Due to the fully algebraic nature of these identities our results extend to a vast class of quantum groups. The techniques introduced here could be relevant for investigating the scaling properties of non-topological state sums, proposed as models of quantum gravity in 4D, under refinement of the cellular decomposition
Topological hierarchy matters — topological matters with superlattices of defects
International Nuclear Information System (INIS)
He Jing; Kou Su-Peng
2016-01-01
Topological insulators/superconductors are new states of quantum matter with metallic edge/surface states. In this paper, we review the defects effect in these topological states and study new types of topological matters — topological hierarchy matters. We find that both topological defects (quantized vortices) and non topological defects (vacancies) can induce topological mid-gap states in the topological hierarchy matters after considering the superlattice of defects. These topological mid-gap states have nontrivial topological properties, including the nonzero Chern number and the gapless edge states. Effective tight-binding models are obtained to describe the topological mid-gap states in the topological hierarchy matters. (topical review)
The coupling of Poisson sigma models to topological backgrounds
Energy Technology Data Exchange (ETDEWEB)
Rosa, Dario [School of Physics, Korea Institute for Advanced Study,Seoul 02455 (Korea, Republic of)
2016-12-13
We extend the coupling to the topological backgrounds, recently worked out for the 2-dimensional BF-model, to the most general Poisson sigma models. The coupling involves the choice of a Casimir function on the target manifold and modifies the BRST transformations. This in turn induces a change in the BRST cohomology of the resulting theory. The observables of the coupled theory are analyzed and their geometrical interpretation is given. We finally couple the theory to 2-dimensional topological gravity: this is the first step to study a topological string theory in propagation on a Poisson manifold. As an application, we show that the gauge-fixed vectorial supersymmetry of the Poisson sigma models has a natural explanation in terms of the theory coupled to topological gravity.
International Nuclear Information System (INIS)
Pope, C.N.
1980-02-01
The material contained in this thesis is concerned with the functional integral approach to the quantum theory of gravity. It seems to be necessary to work with metrics of positive definite signature (Euclidean metrics) and then analytically continue the result back to the Lorentzian regime. The dominant contributions to the functional integral come from metrics which are stationary points of the action, i.e. classical solutions of the Euclideanized Einstein equations. These are known as Gravitational Instantons. Boundary conditions have to be placed upon the metrics included in the functional integral, and these are determined by the physical problem being considered. Three types of boundary condition have arisen in this context, corresponding to (i) zero temperature physics, and the calculation of particle scattering amplitudes, (ii) finite temperature effects, such as black hole radiance, and (iii) the study of the structure of the gravitational vacuum on Planck length scales. Instantons in the first category are asymptotically flat in all four directions, those in the second are asymptotically flat in three directions and periodic in the fourth, and those which arise in studying the gravitational vacuum are compact without boundaries. Much of the thesis is concerned with considering these various kinds of instanton, and particularly with the effects of their non-trivial topology. One way in which this can be investigated is by means of the various topological index theorems, and these are applied to a variety of situations. Self-dual metrics seem to have particular significance in quantum gravity, and they are discussed in detail. Finally, some recent work on the calculation of the propagation of particles in the gravitational vacuum is described. (author)
International Nuclear Information System (INIS)
Giribet, G E
2005-01-01
Claus Kiefer presents his book, Quantum Gravity, with his hope that '[the] book will convince readers of [the] outstanding problem [of unification and quantum gravity] and encourage them to work on its solution'. With this aim, the author presents a clear exposition of the fundamental concepts of gravity and the steps towards the understanding of its quantum aspects. The main part of the text is dedicated to the analysis of standard topics in the formulation of general relativity. An analysis of the Hamiltonian formulation of general relativity and the canonical quantization of gravity is performed in detail. Chapters four, five and eight provide a pedagogical introduction to the basic concepts of gravitational physics. In particular, aspects such as the quantization of constrained systems, the role played by the quadratic constraint, the ADM decomposition, the Wheeler-de Witt equation and the problem of time are treated in an expert and concise way. Moreover, other specific topics, such as the minisuperspace approach and the feasibility of defining extrinsic times for certain models, are discussed as well. The ninth chapter of the book is dedicated to the quantum gravitational aspects of string theory. Here, a minimalistic but clear introduction to string theory is presented, and this is actually done with emphasis on gravity. It is worth mentioning that no hard (nor explicit) computations are presented, even though the exposition covers the main features of the topic. For instance, black hole statistical physics (within the framework of string theory) is developed in a pedagogical and concise way by means of heuristical arguments. As the author asserts in the epilogue, the hope of the book is to give 'some impressions from progress' made in the study of quantum gravity since its beginning, i.e., since the end of 1920s. In my opinion, Kiefer's book does actually achieve this goal and gives an extensive review of the subject. (book review)
Generalized modified gravity in large extra dimensions
International Nuclear Information System (INIS)
Aslan, Onder; Demir, Durmus A.
2006-01-01
We discuss effective interactions among brane matter induced by modifications of higher-dimensional Einstein gravity through the replacement of Einstein-Hilbert term with a generic function f(R,R AB R AB ,R ABCD R ABCD ) of the curvature tensors. We determine gravi-particle spectrum of the theory, and perform a comparative analysis of its predictions with those of the Einstein gravity within Arkani-Hamed-Dvali-Dimopoulos (ADD) setup. We find that this general higher-curvature quantum gravity theory contributes to scatterings among both massive and massless brane matter (in contrast to much simpler generalization of the Einstein gravity, f(R), which influences only the massive matter), and therefore, can be probed via various scattering processes at present and future colliders and directly confronted with the ADD expectations. In addition to collision processes which proceed with tree-level gravi-particle exchange, effective interactions among brane matter are found to exhibit a strong sensitivity to higher-curvature gravity via the gravi-particle loops. Furthermore, particle collisions with missing energy in their final states are found to be sensitive to additional gravi-particles not found in Einstein gravity. In general, road to a correct description of quantum gravity above Fermi energies depends crucially on if collider and other search methods end up with a negative or positive answer for the presence of higher-curvature gravitational interactions
Massive Black Holes and Galaxies
CERN. Geneva
2016-01-01
Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.
Generating a hot big bang via a change in topology
International Nuclear Information System (INIS)
Kandvup, H.E.
1990-01-01
This paper uses ideas developed recently in semiclassical quantum gravity to argue that many qualitative features of the hot big bang generally assumed in cosmology may be explained by the hypothesis that, interpreted semiclassically, the universe tunnelled into being via a quantum fluctuation from a small (Planck-sized), topologically complex entity to a topologically trivial entity (like a Friedmann universe) that rapidly grew to a more macroscopic size
Generating a hot big bang via a change in topology
Energy Technology Data Exchange (ETDEWEB)
Kandvup, H.E. (Florida Univ., Gainesville, FL (USA). Space Astronomy Lab.); Masur, P.O. (Institute for Fundamental Theory, Univ. of Florida, Gainesville, FL (US))
1990-08-01
This paper uses ideas developed recently in semiclassical quantum gravity to argue that many qualitative features of the hot big bang generally assumed in cosmology may be explained by the hypothesis that, interpreted semiclassically, the universe tunnelled into being via a quantum fluctuation from a small (Planck-sized), topologically complex entity to a topologically trivial entity (like a Friedmann universe) that rapidly grew to a more macroscopic size.
Pipinos, Savas
2010-01-01
This article describes one classroom activity in which the author simulates the Newtonian gravity, and employs the Euclidean Geometry with the use of new technologies (NT). The prerequisites for this activity were some knowledge of the formulae for a particle free fall in Physics and most certainly, a good understanding of the notion of similarity…
F.C. Gruau; J.T. Tromp (John)
1999-01-01
textabstractWe consider the problem of establishing gravity in cellular automata. In particular, when cellular automata states can be partitioned into empty, particle, and wall types, with the latter enclosing rectangular areas, we desire rules that will make the particles fall down and pile up on
Classical gravity with higher derivatives
International Nuclear Information System (INIS)
Stelle, K.S.
1978-01-01
Inclusion of the four-derivative terms ∫Rsub(μν) Rsup(μν)(-g)sup(1/2) and ∫R 2 (-g)sup(1/2) into the gravitational action gives a class of effectively multimass models of gravity. In addition to the usual massless excitations of the field, there are now, for general amounts of the two new terms, massive spin-two and massive scalar excitations, with a total of eight degrees of freedom. The massive spin-two part of the field has negative energy. Specific ration of the two new terms give models with either the massive tensor or the massive scalar missing, with correspondingly fewer degrees of freedom. The static, linearized solutions of the field equations are combinations of Newtonian and Yukawa potentials. Owing to the Yukawa form of the corrections, observational evidence sets only very weak restrictions on the new masses. The acceptable static metric solutions in the full nonlinear theory are regular at the origin. The dynamical content of the linearized field is analyzed by reducing the fourth-order field equations to separated second-order equations, related by coupling to external sources in a fixed ratio. This analysis is carried out into the various helicity components using the transverse-traceless decomposition of the metric. (author)
Book Review: Computational Topology
DEFF Research Database (Denmark)
Raussen, Martin
2011-01-01
Computational Topology by Herbert Edelsbrunner and John L. Harer. American Matheamtical Society, 2010 - ISBN 978-0-8218-4925-5......Computational Topology by Herbert Edelsbrunner and John L. Harer. American Matheamtical Society, 2010 - ISBN 978-0-8218-4925-5...
Classical and quantum integrability of 2D dilaton gravities in Euclidean space
International Nuclear Information System (INIS)
Bergamin, L; Grumiller, D; Kummer, W; Vassilevich, D V
2005-01-01
Euclidean dilaton gravity in two dimensions is studied exploiting its representation as a complexified first order gravity model. All local classical solutions are obtained. A global discussion reveals that for a given model only a restricted class of topologies is consistent with the metric and the dilaton. A particular case of string motivated Liouville gravity is studied in detail. Path integral quantization in generic Euclidean dilaton gravity is performed non-perturbatively by analogy to the Minkowskian case
Topological higher gauge theory: From BF to BFCG theory
International Nuclear Information System (INIS)
Girelli, F.; Pfeiffer, H.; Popescu, E. M.
2008-01-01
We study generalizations of three- and four-dimensional BF theories in the context of higher gauge theory. First, we construct topological higher gauge theories as discrete state sum models and explain how they are related to the state sums of Yetter, Mackaay, and Porter. Under certain conditions, we can present their corresponding continuum counterparts in terms of classical Lagrangians. We then explain that two of these models are already familiar from the literature: the ΣΦEA model of three-dimensional gravity coupled to topological matter and also a four-dimensional model of BF theory coupled to topological matter
Free Boolean Topological Groups
Directory of Open Access Journals (Sweden)
Ol’ga Sipacheva
2015-11-01
Full Text Available Known and new results on free Boolean topological groups are collected. An account of the properties that these groups share with free or free Abelian topological groups and properties specific to free Boolean groups is given. Special emphasis is placed on the application of set-theoretic methods to the study of Boolean topological groups.
A Immirzi-like parameter for 3D quantum gravity
International Nuclear Information System (INIS)
Bonzom, Valentin; Livine, Etera R
2008-01-01
We study an Immirzi-like ambiguity in three-dimensional quantum gravity. It shares some features with the Immirzi parameter of four-dimensional loop quantum gravity: it does not affect the equations of motion, but modifies the Poisson brackets and the constraint algebra at the canonical level. We focus on the length operator and show how to define it through non-commuting fluxes. We compute its spectrum and show the effect of this Immirzi-like ambiguity. Finally, we extend these considerations to 4D gravity and show how the different topological modifications of the action affect the canonical structure of loop quantum gravity
Fractal universe and quantum gravity.
Calcagni, Gianluca
2010-06-25
We propose a field theory which lives in fractal spacetime and is argued to be Lorentz invariant, power-counting renormalizable, ultraviolet finite, and causal. The system flows from an ultraviolet fixed point, where spacetime has Hausdorff dimension 2, to an infrared limit coinciding with a standard four-dimensional field theory. Classically, the fractal world where fields live exchanges energy momentum with the bulk with integer topological dimension. However, the total energy momentum is conserved. We consider the dynamics and the propagator of a scalar field. Implications for quantum gravity, cosmology, and the cosmological constant are discussed.
International Nuclear Information System (INIS)
Isham, C.
1989-01-01
Gravitational effects are seen as arising from a curvature in spacetime. This must be reconciled with gravity's apparently passive role in quantum theory to achieve a satisfactory quantum theory of gravity. The development of grand unified theories has spurred the search, with forces being of equal strength at a unification energy of 10 15 - 10 18 GeV, with the ''Plank length'', Lp ≅ 10 -35 m. Fundamental principles of general relativity and quantum mechanics are outlined. Gravitons are shown to have spin-0, as mediators of gravitation force in the classical sense or spin-2 which are related to the quantisation of general relativity. Applying the ideas of supersymmetry to gravitation implies partners for the graviton, especially the massless spin 3/2 fermion called a gravitino. The concept of supersymmetric strings is introduced and discussed. (U.K.)
International Nuclear Information System (INIS)
Markov, M.A.; West, P.C.
1984-01-01
This book discusses the state of the art of quantum gravity, quantum effects in cosmology, quantum black-hole physics, recent developments in supergravity, and quantum gauge theories. Topics considered include the problems of general relativity, pregeometry, complete cosmological theories, quantum fluctuations in cosmology and galaxy formation, a new inflationary universe scenario, grand unified phase transitions and the early Universe, the generalized second law of thermodynamics, vacuum polarization near black holes, the relativity of vacuum, black hole evaporations and their cosmological consequences, currents in supersymmetric theories, the Kaluza-Klein theories, gauge algebra and quantization, and twistor theory. This volume constitutes the proceedings of the Second Seminar on Quantum Gravity held in Moscow in 1981
Chiral fermions in asymptotically safe quantum gravity.
Meibohm, J; Pawlowski, J M
2016-01-01
We study the consistency of dynamical fermionic matter with the asymptotic safety scenario of quantum gravity using the functional renormalisation group. Since this scenario suggests strongly coupled quantum gravity in the UV, one expects gravity-induced fermion self-interactions at energies of the Planck scale. These could lead to chiral symmetry breaking at very high energies and thus to large fermion masses in the IR. The present analysis which is based on the previous works (Christiansen et al., Phys Rev D 92:121501, 2015; Meibohm et al., Phys Rev D 93:084035, 2016), concludes that gravity-induced chiral symmetry breaking at the Planck scale is avoided for a general class of NJL-type models. We find strong evidence that this feature is independent of the number of fermion fields. This finding suggests that the phase diagram for these models is topologically stable under the influence of gravitational interactions.
Can chaos be observed in quantum gravity?
International Nuclear Information System (INIS)
Dittrich, Bianca; Höhn, Philipp A.; Koslowski, Tim A.; Nelson, Mike I.
2017-01-01
Full general relativity is almost certainly ‘chaotic’. We argue that this entails a notion of non-integrability: a generic general relativistic model, at least when coupled to cosmologically interesting matter, likely possesses neither differentiable Dirac observables nor a reduced phase space. It follows that the standard notion of observable has to be extended to include non-differentiable or even discontinuous generalized observables. These cannot carry Poisson-algebraic structures and do not admit a standard quantization; one thus faces a quantum representation problem of gravitational observables. This has deep consequences for a quantum theory of gravity, which we investigate in a simple model for a system with Hamiltonian constraint that fails to be completely integrable. We show that basing the quantization on standard topology precludes a semiclassical limit and can even prohibit any solutions to the quantum constraints. Our proposed solution to this problem is to refine topology such that a complete set of Dirac observables becomes continuous. In the toy model, it turns out that a refinement to a polymer-type topology, as e.g. used in loop gravity, is sufficient. Basing quantization of the toy model on this finer topology, we find a complete set of quantum Dirac observables and a suitable semiclassical limit. This strategy is applicable to realistic candidate theories of quantum gravity and thereby suggests a solution to a long-standing problem which implies ramifications for the very concept of quantization. Our work reveals a qualitatively novel facet of chaos in physics and opens up a new avenue of research on chaos in gravity which hints at deep insights into the structure of quantum gravity.
Can chaos be observed in quantum gravity?
Energy Technology Data Exchange (ETDEWEB)
Dittrich, Bianca, E-mail: bdittrich@perimeterinstitute.ca [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada); Höhn, Philipp A., E-mail: p.hoehn@univie.ac.at [Vienna Center for Quantum Science and Technology, and Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna (Austria); Koslowski, Tim A., E-mail: koslowski@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apartado Postal 70-543, México D.F. 04510 (Mexico); Nelson, Mike I., E-mail: mike@aims.edu.gh [African Institute for Mathematical Sciences, P.O Box LG 197, Legon, Accra (Ghana)
2017-06-10
Full general relativity is almost certainly ‘chaotic’. We argue that this entails a notion of non-integrability: a generic general relativistic model, at least when coupled to cosmologically interesting matter, likely possesses neither differentiable Dirac observables nor a reduced phase space. It follows that the standard notion of observable has to be extended to include non-differentiable or even discontinuous generalized observables. These cannot carry Poisson-algebraic structures and do not admit a standard quantization; one thus faces a quantum representation problem of gravitational observables. This has deep consequences for a quantum theory of gravity, which we investigate in a simple model for a system with Hamiltonian constraint that fails to be completely integrable. We show that basing the quantization on standard topology precludes a semiclassical limit and can even prohibit any solutions to the quantum constraints. Our proposed solution to this problem is to refine topology such that a complete set of Dirac observables becomes continuous. In the toy model, it turns out that a refinement to a polymer-type topology, as e.g. used in loop gravity, is sufficient. Basing quantization of the toy model on this finer topology, we find a complete set of quantum Dirac observables and a suitable semiclassical limit. This strategy is applicable to realistic candidate theories of quantum gravity and thereby suggests a solution to a long-standing problem which implies ramifications for the very concept of quantization. Our work reveals a qualitatively novel facet of chaos in physics and opens up a new avenue of research on chaos in gravity which hints at deep insights into the structure of quantum gravity.
Computational chaos in massively parallel neural networks
Barhen, Jacob; Gulati, Sandeep
1989-01-01
A fundamental issue which directly impacts the scalability of current theoretical neural network models to massively parallel embodiments, in both software as well as hardware, is the inherent and unavoidable concurrent asynchronicity of emerging fine-grained computational ensembles and the possible emergence of chaotic manifestations. Previous analyses attributed dynamical instability to the topology of the interconnection matrix, to parasitic components or to propagation delays. However, researchers have observed the existence of emergent computational chaos in a concurrently asynchronous framework, independent of the network topology. Researcher present a methodology enabling the effective asynchronous operation of large-scale neural networks. Necessary and sufficient conditions guaranteeing concurrent asynchronous convergence are established in terms of contracting operators. Lyapunov exponents are computed formally to characterize the underlying nonlinear dynamics. Simulation results are presented to illustrate network convergence to the correct results, even in the presence of large delays.
Energy Technology Data Exchange (ETDEWEB)
Kalb, Jeffrey L.; Lee, David S.
2008-01-01
Emerging high-bandwidth, low-latency network technology has made network-based architectures both feasible and potentially desirable for use in satellite payload architectures. The selection of network topology is a critical component when developing these multi-node or multi-point architectures. This study examines network topologies and their effect on overall network performance. Numerous topologies were reviewed against a number of performance, reliability, and cost metrics. This document identifies a handful of good network topologies for satellite applications and the metrics used to justify them as such. Since often multiple topologies will meet the requirements of the satellite payload architecture under development, the choice of network topology is not easy, and in the end the choice of topology is influenced by both the design characteristics and requirements of the overall system and the experience of the developer.
Dipolar dark matter with massive bigravity
International Nuclear Information System (INIS)
Blanchet, Luc; Heisenberg, Lavinia
2015-01-01
Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the dark matter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model
Is nonrelativistic gravity possible?
International Nuclear Information System (INIS)
Kocharyan, A. A.
2009-01-01
We study nonrelativistic gravity using the Hamiltonian formalism. For the dynamics of general relativity (relativistic gravity) the formalism is well known and called the Arnowitt-Deser-Misner (ADM) formalism. We show that if the lapse function is constrained correctly, then nonrelativistic gravity is described by a consistent Hamiltonian system. Surprisingly, nonrelativistic gravity can have solutions identical to relativistic gravity ones. In particular, (anti-)de Sitter black holes of Einstein gravity and IR limit of Horava gravity are locally identical.
Discussion on massive gravitons and propagating torsion in arbitrary dimensions
International Nuclear Information System (INIS)
Hernaski, C.A.; Vargas-Paredes, A.A.; Helayel-Neto, J.A.
2009-01-01
Full text. Massive gravity has been an issue of particular interest since the early days of Quantum Gravity. More recently, in connection with models based on brane-world scenarios, the discussion of massive gravitons is drawing a great deal of attention, in view of the possibility of their production at LHC and the feasibility of detection of quantum gravity effects at the TeV scale. In this paper, we reassess a particular R 2 -type gravity action in D dimensions, recently studied by Nakasone and Oda, taking now torsion effects into account. Considering that the vielbein and the spin connection carry independent propagating degrees of freedom, we conclude that ghosts and tachyons are absent only if torsion is non-propagating, and we also conclude that there is no room for massive gravitons. To include these excitations, we understand how to enlarge Nakasone-Oda's model by means of explicit torsion terms in the action and we discuss the unitarity of the enlarged model for arbitrary dimensions. To make this we construct a complete basis of operators that projects the degrees of freedom of the dynamical fields of the model in their irreducible spin decomposition. The outcome is that we find a set of Lagrangians with a massive graviton that, in D=4, reproduce those already studied in the literature. (author)
Magnetic Fields Versus Gravity
Hensley, Kerry
2018-04-01
Deep within giant molecular clouds, hidden by dense gas and dust, stars form. Unprecedented data from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the intricate magnetic structureswoven throughout one of the most massive star-forming regions in the Milky Way.How Stars Are BornThe Horsehead Nebulasdense column of gas and dust is opaque to visible light, but this infrared image reveals the young stars hidden in the dust. [NASA/ESA/Hubble Heritage Team]Simple theory dictates that when a dense clump of molecular gas becomes massive enough that its self-gravity overwhelms the thermal pressure of the cloud, the gas collapses and forms a star. In reality, however, star formation is more complicated than a simple give and take between gravity and pressure. Thedusty molecular gas in stellar nurseries is permeated with magnetic fields, which are thought to impede the inward pull of gravity and slow the rate of star formation.How can we learn about the magnetic fields of distant objects? One way is by measuring dust polarization. An elongated dust grain will tend to align itself with its short axis parallel to the direction of the magnetic field. This systematic alignment of the dust grains along the magnetic field lines polarizes the dust grains emission perpendicular to the local magnetic field. This allows us to infer the direction of the magnetic field from the direction of polarization.Magnetic field orientations for protostars e2 and e8 derived from Submillimeter Array observations (panels a through c) and ALMA observations (panels d and e). Click to enlarge. [Adapted from Koch et al. 2018]Tracing Magnetic FieldsPatrick Koch (Academia Sinica, Taiwan) and collaborators used high-sensitivity ALMA observations of dust polarization to learn more about the magnetic field morphology of Milky Way star-forming region W51. W51 is one of the largest star-forming regions in our galaxy, home to high-mass protostars e2, e8, and North.The ALMA observations reveal
Quantum gravity and Standard-Model-like fermions
International Nuclear Information System (INIS)
Eichhorn, Astrid; Lippoldt, Stefan
2017-01-01
We discover that chiral symmetry does not act as an infrared attractor of the renormalization group flow under the impact of quantum gravity fluctuations. Thus, observationally viable quantum gravity models must respect chiral symmetry. In our truncation, asymptotically safe gravity does, as a chiral fixed point exists. A second non-chiral fixed point with massive fermions provides a template for models with dark matter. This fixed point disappears for more than 10 fermions, suggesting that an asymptotically safe ultraviolet completion for the standard model plus gravity enforces chiral symmetry.
International Nuclear Information System (INIS)
Gribbin, John.
1990-01-01
This paper looks at Einstein's Theory of General Relativity and lists its accomplishments in explaining many problems in gravitation and astrophysics. It was Einstin's genius that led to our present comprehensive theory of gravity. Various ideas central to the theory are explained, such as the bending of space and time by massive objects, geodesics, the origin of the universe. In astrophysics, recent discoveries such as black holes, quasars, gravitational lenses, gravitational radiation, such as that coming from pulsars, can all be explained and understood using Einstein's ideas. (UK)
International Nuclear Information System (INIS)
Schupp, P.
2007-01-01
Heuristic arguments suggest that the classical picture of smooth commutative spacetime should be replaced by some kind of quantum / noncommutative geometry at length scales and energies where quantum as well as gravitational effects are important. Motivated by this idea much research has been devoted to the study of quantum field theory on noncommutative spacetimes. More recently the focus has started to shift back to gravity in this context. We give an introductory overview to the formulation of general relativity in a noncommutative spacetime background and discuss the possibility of exact solutions. (author)
Gravity localization in sine-Gordon braneworlds
International Nuclear Information System (INIS)
Cruz, W.T.; Maluf, R.V.; Sousa, L.J.S.; Almeida, C.A.S.
2016-01-01
In this work we study two types of five-dimensional braneworld models given by sine-Gordon potentials. In both scenarios, the thick brane is generated by a real scalar field coupled to gravity. We focus our investigation on the localization of graviton field and the behaviour of the massive spectrum. In particular, we analyse the localization of massive modes by means of a relative probability method in a Quantum Mechanics context. Initially, considering a scalar field sine-Gordon potential, we find a localized state to the graviton at zero mode. However, when we consider a double sine-Gordon potential, the brane structure is changed allowing the existence of massive resonant states. The new results show how the existence of an internal structure can aid in the emergence of massive resonant modes on the brane.
Higgsless superconductivity from topological defects in compact BF terms
Directory of Open Access Journals (Sweden)
M. Cristina Diamantini
2015-02-01
Full Text Available We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalisable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D−1-form fictitious pseudovector gauge field which originates from the condensation of topological defects in compact low-energy effective BF theories. In the average field approximation, the corresponding uniform emergent charge creates a gap for the (D−2-dimensional branes via the Magnus force, the dual of the Lorentz force. One particular combination of intrinsic and emergent charge fluctuations that leaves the total charge distribution invariant constitutes an isolated gapless mode leading to superfluidity. The remaining massive modes organise themselves into a D-dimensional charged, massive vector. There is no massive Higgs scalar as there is no local order parameter. When electromagnetism is switched on, the photon acquires mass by the topological BF mechanism. Although the charge of the gapless mode (2 and the topological order (4 are the same as those of the standard Higgs model, the two models of superconductivity are clearly different since the origins of the gap, reflected in the high-energy sectors are totally different. In 2D this type of superconductivity is explicitly realised as global superconductivity in Josephson junction arrays. In 3D this model predicts a possible phase transition from topological insulators to Higgsless superconductors.
Planckian Interacting Massive Particles as Dark Matter
DEFF Research Database (Denmark)
Garny, Mathias; Sandora, McCullen; Sloth, Martin S.
2016-01-01
. In this case the WIMP miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian Interacting Massive Particle......, we show that the most natural mass larger than $0.01\\,\\textrm{M}_p$ is already ruled out by the absence of tensor modes in the CMB. This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the KK graviton mode...... as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark...
International Nuclear Information System (INIS)
Hooft, G.
2012-01-01
The dynamical degree of freedom for the gravitational force is the metric tensor, having 10 locally independent degrees of freedom (of which 4 can be used to fix the coordinate choice). In conformal gravity, we split this field into an overall scalar factor and a nine-component remainder. All unrenormalizable infinities are in this remainder, while the scalar component can be handled like any other scalar field such as the Higgs field. In this formalism, conformal symmetry is spontaneously broken. An imperative demand on any healthy quantum gravity theory is that black holes should be described as quantum systems with micro-states as dictated by the Hawking-Bekenstein theory. This requires conformal symmetry that may be broken spontaneously but not explicitly, and this means that all conformal anomalies must cancel out. Cancellation of conformal anomalies yields constraints on the matter sector as described by some universal field theory. Thus black hole physics may eventually be of help in the construction of unified field theories. (author)
International Nuclear Information System (INIS)
Eberhart, M.
1996-01-01
A systematic study of the charge density topologies corresponding to a number of transition metal aluminides with the B2 structure indicates that unstable crystal structures are sometimes associated with uncharacteristic topologies. This observation invites the speculation that the distance to a topological instability might relate to a metals phase behavior. Following this speculation, a metric is imposed on the topological theory of Bader, producing a geometrical theory, where it is now possible to assign a distance from a calculated charge density topology to a topological instability. For the cubic transition metals, these distances are shown to correlate with single crystal elastic constants, where the metals that are furthest from an instability are observed to be the stiffest. (author). 16 refs., 1 tab., 9 figs
Topological mirror superconductivity.
Zhang, Fan; Kane, C L; Mele, E J
2013-08-02
We demonstrate the existence of topological superconductors (SCs) protected by mirror and time-reversal symmetries. D-dimensional (D=1, 2, 3) crystalline SCs are characterized by 2(D-1) independent integer topological invariants, which take the form of mirror Berry phases. These invariants determine the distribution of Majorana modes on a mirror symmetric boundary. The parity of total mirror Berry phase is the Z(2) index of a class DIII SC, implying that a DIII topological SC with a mirror line must also be a topological mirror SC but not vice versa and that a DIII SC with a mirror plane is always time-reversal trivial but can be mirror topological. We introduce representative models and suggest experimental signatures in feasible systems. Advances in quantum computing, the case for nodal SCs, the case for class D, and topological SCs protected by rotational symmetries are pointed out.
Interactive Topology Optimization
DEFF Research Database (Denmark)
Nobel-Jørgensen, Morten
Interactivity is the continuous interaction between the user and the application to solve a task. Topology optimization is the optimization of structures in order to improve stiffness or other objectives. The goal of the thesis is to explore how topology optimization can be used in applications...... on theory of from human-computer interaction which is described in Chapter 2. Followed by a description of the foundations of topology optimization in Chapter 3. Our applications for topology optimization in 2D and 3D are described in Chapter 4 and a game which trains the human intuition of topology...... optimization is presented in Chapter 5. Topology optimization can also be used as an interactive modeling tool with local control which is presented in Chapter 6. Finally, Chapter 7 contains a summary of the findings and concludes the dissertation. Most of the presented applications of the thesis are available...
Clay, Adam
2016-01-01
This book deals with the connections between topology and ordered groups. It begins with a self-contained introduction to orderable groups and from there explores the interactions between orderability and objects in low-dimensional topology, such as knot theory, braid groups, and 3-manifolds, as well as groups of homeomorphisms and other topological structures. The book also addresses recent applications of orderability in the studies of codimension-one foliations and Heegaard-Floer homology. The use of topological methods in proving algebraic results is another feature of the book. The book was written to serve both as a textbook for graduate students, containing many exercises, and as a reference for researchers in topology, algebra, and dynamical systems. A basic background in group theory and topology is the only prerequisite for the reader.
Topological Foundations of Electromagnetism
Barrett, Terrence W
2008-01-01
Topological Foundations of Electromagnetism seeks a fundamental understanding of the dynamics of electromagnetism; and marshals the evidence that in certain precisely defined topological conditions, electromagnetic theory (Maxwell's theory) must be extended or generalized in order to provide an explanation and understanding of, until now, unusual electromagnetic phenomena. Key to this generalization is an understanding of the circumstances under which the so-called A potential fields have physical effects. Basic to the approach taken is that the topological composition of electromagnetic field
Siino, Masaru
1997-01-01
The topologies of event horizons are investigated. Considering the existence of the endpoint of the event horizon, it cannot be differentiable. Then there are the new possibilities of the topology of the event horizon though they are excluded in smooth event horizons. The relation between the topology of the event horizon and the endpoint of it is revealed. A torus event horizon is caused by two-dimensional endpoints. One-dimensional endpoints provide the coalescence of spherical event horizo...
Gulamsarwar, Syazwani; Salleh, Zabidin
2017-08-01
The purpose of this paper is to generalize the notions of Adler's topological entropy along with their several fundamental properties. A function f : X → Y is said to be R-map if f-1 (V) is regular open in X for every regular open set V in Y. Thus, we initiated a notion of topological nearly entropy for topological R-dynamical systems which is based on nearly compact relative to the space by using R-map.
Decorrelating topology with HMC
International Nuclear Information System (INIS)
Lippert, Th.; Alles, B.; Bali, G.; D'Elia, M.; Di Giacomo, A.; Eicker, N.; Guesken, S.; Schilling, K.; Spitz, A.; Struckmann, T.; Ueberholz, P.; Viehoff, J.
1999-01-01
The investigation of the decorrelation efficiency of the HMC algorithm with respect to vacuum topology is a prerequisite for trustworthy full QCD simulations, in particular for the computation of topology sensitive quantities. We demonstrate that for ((m π )/(m ρ ))-ratios ≥ 0.69 sufficient tunneling between the topological sectors can be achieved, for two flavours of dynamical Wilson fermions close to the scaling region (β 5.6). Our results are based on time series of length 5000 trajectories
National Oceanic and Atmospheric Administration, Department of Commerce — This data base (14,559 records) was received in January 1986. Principal gravity parameters include elevation and observed gravity. The observed gravity values are...
National Oceanic and Atmospheric Administration, Department of Commerce — The NGS Absolute Gravity data (78 stations) was received in July 1993. Principal gravity parameters include Gravity Value, Uncertainty, and Vertical Gradient. The...
Directory of Open Access Journals (Sweden)
Ali Bajravani
2018-04-01
Full Text Available By substituting the usual notion of open sets in a topological space $X$ with a suitable collection of maps from $X$ to a frame $L$, we introduce the notion of L-topological spaces. Then, we proceed to study the classical notions and properties of usual topological spaces to the newly defined mathematical notion. Our emphasis would be concentrated on the well understood classical connectedness, quotient and compactness notions, where we prove the Thychonoff's theorem and connectedness property for ultra product of $L$-compact and $L$-connected topological spaces, respectively.
Singh, Tej Bahadur
2013-01-01
Topological SpacesMetric Spaces Topologies Derived Concepts Bases Subspaces Continuity and ProductsContinuityProduct TopologyConnectednessConnected Spaces Components Path-Connected Spaces Local ConnectivityConvergence Sequences Nets Filters Hausdorff SpacesCountability Axioms 1st and 2nd Countable Spaces Separable and Lindelöf SpacesCompactnessCompact Spaces Countably Compact Spaces Compact Metric Spaces Locally Compact Spaces Proper Maps Topological Constructions Quotient Spaces Identification Maps Cones, Suspensions and Joins Wedge Sums and Smash Products Adjunction Spaces Coherent Topologie
Topological Gyroscopic Metamaterials
Nash, Lisa Michelle
Topological materials are generally insulating in their bulk, with protected conducting states on their boundaries that are robust against disorder and perturbation of material property. The existence of these conducting edge states is characterized by an integer topological invariant. Though the phenomenon was first discovered in electronic systems, recent years have shown that topological states exist in classical systems as well. In this thesis we are primarily concerned with the topological properties of gyroscopic materials, which are created by coupling networks of fast-spinning objects. Through a series of simulations, numerical calculations, and experiments, we show that these materials can support topological edge states. We find that edge states in these gyroscopic metamaterials bear the hallmarks of topology related to broken time reversal symmetry: they transmit excitations unidirectionally and are extremely robust against experimental disorder. We also explore requirements for topology by studying several lattice configurations and find that topology emerges naturally in gyroscopic systems.A simple prescription can be used to create many gyroscopic lattices. Though many of our gyroscopic networks are periodic, we explore amorphous point-sets and find that topology also emerges in these networks.
Morita, K
1989-01-01
Being an advanced account of certain aspects of general topology, the primary purpose of this volume is to provide the reader with an overview of recent developments.The papers cover basic fields such as metrization and extension of maps, as well as newly-developed fields like categorical topology and topological dynamics. Each chapter may be read independently of the others, with a few exceptions. It is assumed that the reader has some knowledge of set theory, algebra, analysis and basic general topology.
General Topology of the Universe
Pandya, Aalok
2002-01-01
General topology of the universe is descibed. It is concluded that topology of the present universe is greater or stronger than the topology of the universe in the past and topology of the future universe will be stronger or greater than the present topology of the universe. Consequently, the universe remains unbounded.
Massive neutrinos in astrophysics
International Nuclear Information System (INIS)
Qadir, A.
1982-08-01
Massive neutrinos are among the big hopes of cosmologists. If they happen to have the right mass they can close the Universe, explain the motion of galaxies in clusters, provide galactic halos and even, possibly, explain galaxy formation. Tremaine and Gunn have argued that massive neutrinos cannot do all these things. I will explain, here, what some of us believe is wrong with their arguments. (author)
Cosmology and modifications of gravity at large distances
International Nuclear Information System (INIS)
Ziour, R.
2010-01-01
In the framework of General Relativity, the observed current acceleration of the expansion of the Universe requires the presence of a Dark Energy component, whose nature is not well understood. In order to explain the acceleration of the Universe without introducing such a tantalizing source of energy, other gravitation theories have been designed. This thesis is devoted to the study of some of these modified gravity theories, as well as to the observation methods that could constrain them. The first part of this thesis presents a review of modified gravity theories and their motivations. The second part is devoted to the study of the massive gravity theories and of the so-called Vainshtein's mechanism, which allows some of the solutions of Massive Gravity to strongly differ from General Relativity at cosmological scales while satisfying the experimental constraints inside the solar system. For the first time, the validity of the Vainshtein's mechanism is demonstrated, through the study of specific spherically symmetric solutions. The third part deals with scalar modification of gravity; a new model of this sort is presented, inspired by the Vainshtein's mechanism in Massive Gravity. Finally, the fourth part discusses local, astrophysical and cosmological observations that might constrain modified gravity theories. (author)
Aoki, Katsuki; Maeda, Kei-ichi; Misonoh, Yosuke; Okawa, Hirotada
2018-02-01
We find vacuum solutions such that massive gravitons are confined in a local spacetime region by their gravitational energy in asymptotically flat spacetimes in the context of the bigravity theory. We call such self-gravitating objects massive graviton geons. The basic equations can be reduced to the Schrödinger-Poisson equations with the tensor "wave function" in the Newtonian limit. We obtain a nonspherically symmetric solution with j =2 , ℓ=0 as well as a spherically symmetric solution with j =0 , ℓ=2 in this system where j is the total angular momentum quantum number and ℓ is the orbital angular momentum quantum number, respectively. The energy eigenvalue of the Schrödinger equation in the nonspherical solution is smaller than that in the spherical solution. We then study the perturbative stability of the spherical solution and find that there is an unstable mode in the quadrupole mode perturbations which may be interpreted as the transition mode to the nonspherical solution. The results suggest that the nonspherically symmetric solution is the ground state of the massive graviton geon. The massive graviton geons may decay in time due to emissions of gravitational waves but this timescale can be quite long when the massive gravitons are nonrelativistic and then the geons can be long-lived. We also argue possible prospects of the massive graviton geons: applications to the ultralight dark matter scenario, nonlinear (in)stability of the Minkowski spacetime, and a quantum transition of the spacetime.
Noether's stars in f (R) gravity
De Laurentis, Mariafelicia
2018-05-01
The Noether Symmetry Approach can be used to construct spherically symmetric solutions in f (R) gravity. Specifically, the Noether conserved quantity is related to the gravitational mass and a gravitational radius that reduces to the Schwarzschild radius in the limit f (R) → R. We show that it is possible to construct the M- R relation for neutron stars depending on the Noether conserved quantity and the associated gravitational radius. This approach enables the recovery of extreme massive stars that could not be stable in the standard Tolman-Oppenheimer-Volkoff based on General Relativity. Examples are given for some power law f (R) gravity models.
A topological derivative method for topology optimization
DEFF Research Database (Denmark)
Norato, J.; Bendsøe, Martin P.; Haber, RB
2007-01-01
resource constraint. A smooth and consistent projection of the region bounded by the level set onto the fictitious analysis domain simplifies the response analysis and enhances the convergence of the optimization algorithm. Moreover, the projection supports the reintroduction of solid material in void......We propose a fictitious domain method for topology optimization in which a level set of the topological derivative field for the cost function identifies the boundary of the optimal design. We describe a fixed-point iteration scheme that implements this optimality criterion subject to a volumetric...... regions, a critical requirement for robust topology optimization. We present several numerical examples that demonstrate compliance minimization of fixed-volume, linearly elastic structures....
Symmetry reduction of loop quantum gravity
International Nuclear Information System (INIS)
Brunnemann, Johannes; Koslowski, Tim A
2011-01-01
The relation between standard loop quantum cosmology (LQC) and full loop quantum gravity (LQG) fails already at the first nontrivial step: the configuration space of LQC cannot be embedded into the configuration space of full LQG due to a topological obstruction. We investigate this obstruction in detail, because many topological obstructions are the source of physical effects. For this, we derive the topology of a large class of subspaces of the LQG configuration space. This allows us to find the extension of the standard LQC configuration space that admits an embedding in agreement with Fleischhack (arXiv:1010.0449v1 [math-ph]). We then construct the embedding for flat FRW LQC and find the reassuring result that it coincides asymptotically with standard LQC. (paper)
Newtonian gravity in loop quantum gravity
Smolin, Lee
2010-01-01
We apply a recent argument of Verlinde to loop quantum gravity, to conclude that Newton's law of gravity emerges in an appropriate limit and setting. This is possible because the relationship between area and entropy is realized in loop quantum gravity when boundaries are imposed on a quantum spacetime.
Topology optimization approaches
DEFF Research Database (Denmark)
Sigmund, Ole; Maute, Kurt
2013-01-01
Topology optimization has undergone a tremendous development since its introduction in the seminal paper by Bendsøe and Kikuchi in 1988. By now, the concept is developing in many different directions, including “density”, “level set”, “topological derivative”, “phase field”, “evolutionary...
Mendelson, Bert
1990-01-01
Highly regarded for its exceptional clarity, imaginative and instructive exercises, and fine writing style, this concise book offers an ideal introduction to the fundamentals of topology. It provides a simple, thorough survey of elementary topics, starting with set theory and advancing to metric and topological spaces, connectedness, and compactness. 1975 edition.
Modeling Internet Topology Dynamics
Haddadi, H.; Uhlig, S.; Moore, A.; Mortier, R.; Rio, M.
Despite the large number of papers on network topology modeling and inference, there still exists ambiguity about the real nature of the Internet AS and router level topology. While recent findings have illustrated the inaccuracies in maps inferred from BGP peering and traceroute measurements,
Directory of Open Access Journals (Sweden)
Coghetto Roland
2015-12-01
If to each element x of a set X there corresponds a set B(x of subsets of X such that the properties VI, VII, VIII and VIV are satisfied, then there is a unique topological structure on X such that, for each x ∈ X, B(x is the set of neighborhoods of x in this topology.
Reconfigurable topological photonic crystal
Shalaev, Mikhail I.; Desnavi, Sameerah; Walasik, Wiktor; Litchinitser, Natalia M.
2018-02-01
Topological insulators are materials that conduct on the surface and insulate in their interior due to non-trivial topology of the band structure. The edge states on the interface between topological (non-trivial) and conventional (trivial) insulators are topologically protected from scattering due to structural defects and disorders. Recently, it was shown that photonic crystals (PCs) can serve as a platform for realizing a scatter-free propagation of light waves. In conventional PCs, imperfections, structural disorders, and surface roughness lead to significant losses. The breakthrough in overcoming these problems is likely to come from the synergy of the topological PCs and silicon-based photonics technology that enables high integration density, lossless propagation, and immunity to fabrication imperfections. For many applications, reconfigurability and capability to control the propagation of these non-trivial photonic edge states is essential. One way to facilitate such dynamic control is to use liquid crystals (LCs), which allow to modify the refractive index with external electric field. Here, we demonstrate dynamic control of topological edge states by modifying the refractive index of a LC background medium. Background index is changed depending on the orientation of a LC, while preserving the topology of the system. This results in a change of the spectral position of the photonic bandgap and the topological edge states. The proposed concept might be implemented using conventional semiconductor technology, and can be used for robust energy transport in integrated photonic devices, all-optical circuity, and optical communication systems.
Topological Acoustic Delay Line
Zhang, Zhiwang; Tian, Ye; Cheng, Ying; Wei, Qi; Liu, Xiaojun; Christensen, Johan
2018-03-01
Topological protected wave engineering in artificially structured media is at the frontier of ongoing metamaterials research that is inspired by quantum mechanics. Acoustic analogues of electronic topological insulators have recently led to a wealth of new opportunities in manipulating sound propagation with strikingly unconventional acoustic edge modes immune to backscattering. Earlier fabrications of topological insulators are characterized by an unreconfigurable geometry and a very narrow frequency response, which severely hinders the exploration and design of useful devices. Here we establish topologically protected sound in reconfigurable phononic crystals that can be switched on and off simply by rotating its three-legged "atoms" without altering the lattice structure. In particular, we engineer robust phase delay defects that take advantage of the ultrabroadband reflection-free sound propagation. Such topological delay lines serve as a paradigm in compact acoustic devices, interconnects, and electroacoustic integrated circuits.
Geometric approach to a massive p form duality
International Nuclear Information System (INIS)
Arias, Pio J.; Leal, Lorenzo; Perez-Mosquera, J. C.
2003-01-01
Massive theories of Abelian p forms are quantized in a generalized path representation that leads to a description of the phase space in terms of a pair of dual nonlocal operators analogous to the Wilson loop and the 't Hooft disorder operators. Special attention is devoted to the study of the duality between the topologically massive and self-dual models in 2+1 dimensions. It is shown that these models share a geometric representation in which just one nonlocal operator suffices to describe the observables
Pseudotopological quasilocal energy of torsion gravity
Ko, Sheng-Lan; Lin, Feng-Li; Ning, Bo
2017-08-01
Torsion gravity is a natural extension to Einstein gravity in the presence of fermion matter sources. In this paper we adopt Wald's covariant method of calculating the Noether charge to construct the quasilocal energy of the Einstein-Cartan-fermion system, and find that its explicit expression is formally independent of the coupling constant between the torsion and axial current. This seemingly topological nature is unexpected and is reminiscent of the quantum Hall effect and topological insulators. However, a coupling dependence does arise when evaluating it on shell, and thus the situation is pseudotopological. Based on the expression for the quasilocal energy, we evaluate it for a particular solution on the entanglement wedge and find agreement with the holographic relative entropy obtained before. This shows the equivalence of these two quantities in the Einstein-Cartan-fermion system. Moreover, the quasilocal energy in this case is not always positive definite, and thus it provides an example of a swampland in torsion gravity. Based on the covariant Noether charge, we also derive the nonzero fermion effect on the Komar angular momentum. The implications of our results for future tests of torsion gravity in gravitational-wave astronomy are also discussed.
Machine learning topological states
Deng, Dong-Ling; Li, Xiaopeng; Das Sarma, S.
2017-11-01
Artificial neural networks and machine learning have now reached a new era after several decades of improvement where applications are to explode in many fields of science, industry, and technology. Here, we use artificial neural networks to study an intriguing phenomenon in quantum physics—the topological phases of matter. We find that certain topological states, either symmetry-protected or with intrinsic topological order, can be represented with classical artificial neural networks. This is demonstrated by using three concrete spin systems, the one-dimensional (1D) symmetry-protected topological cluster state and the 2D and 3D toric code states with intrinsic topological orders. For all three cases, we show rigorously that the topological ground states can be represented by short-range neural networks in an exact and efficient fashion—the required number of hidden neurons is as small as the number of physical spins and the number of parameters scales only linearly with the system size. For the 2D toric-code model, we find that the proposed short-range neural networks can describe the excited states with Abelian anyons and their nontrivial mutual statistics as well. In addition, by using reinforcement learning we show that neural networks are capable of finding the topological ground states of nonintegrable Hamiltonians with strong interactions and studying their topological phase transitions. Our results demonstrate explicitly the exceptional power of neural networks in describing topological quantum states, and at the same time provide valuable guidance to machine learning of topological phases in generic lattice models.
International Nuclear Information System (INIS)
Govindarajan, T R; Kaul, R K; Suneeta, V
2002-01-01
We study quantum gravity on dS 3 using the Chern-Simons formulation of three-dimensional gravity. We derive an exact expression for the partition function for quantum gravity on dS 3 in a Euclidean path integral approach. We show that the topology of the space relevant for studying de Sitter entropy is a solid torus. The quantum fluctuations of de Sitter space are sectors of configurations of point masses taking a discrete set of values. The partition function gives the correct semiclassical entropy. The sub-leading correction to the entropy is logarithmic in horizon area, with a coefficient -1. We discuss this correction in detail, and show that the sub-leading correction to the entropy from the dS/CFT correspondence agrees with our result. A comparison with the corresponding results for the AdS 3 BTZ black hole is also presented
''Topological'' (Chern-Simons) quantum mechanics
International Nuclear Information System (INIS)
Dunne, G.V.; Jackiw, R.; Trugenberger, C.A.
1990-01-01
We construct quantum-mechanical models that are analogs of three-dimensional, topologically massive as well as Chern-Simons gauge-field theories, and we study the phase-space reductive limiting procedure that takes the former to the latter. The zero-point spectra of operators behave discontinuously in the limit, as a consequence of a nonperturbative quantum-mechanical anomaly. The nature of the limit for wave functions depends on the representation, but is always such that normalization is preserved
Emerging Trends in Topological Insulators and Topological ...
Indian Academy of Sciences (India)
tems can lead to a state that supports zero energy Majorana fermions .... orbital motion is a relativistic effect most pronounced in heavy ... 1D helical edge states appear within the gap with a linear disper- ... free fermion in 1D. .... less, and electrically neutral. ... to be used as a building block for the next generation topological.
Planckian Interacting Massive Particles as Dark Matter.
Garny, Mathias; Sandora, McCullen; Sloth, Martin S
2016-03-11
The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01M_{p} is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter.
Propagating Degrees of Freedom in f(R Gravity
Directory of Open Access Journals (Sweden)
Yun Soo Myung
2016-01-01
Full Text Available We have computed the number of polarization modes of gravitational waves propagating in the Minkowski background in f(R gravity. These are three of two from transverse-traceless tensor modes and one from a massive trace mode, which confirms the results found in the literature. There is no massless breathing mode and the massive trace mode corresponds to the Ricci scalar. A newly defined metric tensor in f(R gravity satisfies the transverse-traceless (TT condition as well as the TT wave equation.
Byrne, Michael
1999-01-01
Einstein said that gravity is an acceleration like any other acceleration. But gravity causes relativistic effects at non-relativistic speeds; so gravity could have relativistic origins. And since the strong force is thought to cause most of mass, and mass is proportional to gravity; the strong force is therefore also proportional to gravity. The strong force could thus cause relativistic increases of mass through the creation of virtual gluons; along with a comparable contraction of space ar...
Epidemiology of Massive Transfusion
DEFF Research Database (Denmark)
Halmin, Märit; Chiesa, Flaminia; Vasan, Senthil K
2016-01-01
in Sweden from 1987 and in Denmark from 1996. A total of 92,057 patients were included. Patients were followed until the end of 2012. MEASUREMENTS AND MAIN RESULTS: Descriptive statistics were used to characterize the patients and indications. Post transfusion mortality was expressed as crude 30-day...... mortality and as long-term mortality using the Kaplan-Meier method and using standardized mortality ratios. The incidence of massive transfusion was higher in Denmark (4.5 per 10,000) than in Sweden (2.5 per 10,000). The most common indication for massive transfusion was major surgery (61.2%) followed...
Epidemiology of massive transfusion
DEFF Research Database (Denmark)
Halmin, M A; Chiesa, F; Vasan, S K
2015-01-01
and to describe characteristics and mortality of massively transfused patients. Methods: We performed a retrospective cohort study based on the Scandinavian Donations and Transfusions (SCANDAT2) database, linking data on blood donation, blood components and transfused patients with inpatient- and population.......4% among women transfused for obstetrical bleeding. Mortality increased gradually with age and among all patients massively transfused at age 80 years, only 26% were alive [TABLE PRESENTED] after 5 years. The relative mortality, early after transfusion, was high and decreased with time since transfusion...
Energy Technology Data Exchange (ETDEWEB)
Hendi, Seyed Hossein [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), Maragha (Iran, Islamic Republic of); Panahiyan, Shahram; Panah, Behzad Eslam [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of)
2015-06-15
In this paper, we consider two first order corrections to both the gravity and the gauge sides of the Einstein-Maxwell gravity: Gauss-Bonnet gravity and quadratic Maxwell invariant as corrections. We obtain horizonless magnetic solutions by implying a metric representing a topological defect. We analyze the geometric properties of the solutions and investigate the effects of both corrections, and find that these solutions may be interpreted as magnetic branes. We study the singularity condition and find a nonsingular spacetime with a conical geometry. We also investigate the effects of different parameters on the deficit angle of spacetime near the origin. (orig.)
International Nuclear Information System (INIS)
Hendi, Seyed Hossein; Panahiyan, Shahram; Panah, Behzad Eslam
2015-01-01
In this paper, we consider two first order corrections to both the gravity and the gauge sides of the Einstein-Maxwell gravity: Gauss-Bonnet gravity and quadratic Maxwell invariant as corrections. We obtain horizonless magnetic solutions by implying a metric representing a topological defect. We analyze the geometric properties of the solutions and investigate the effects of both corrections, and find that these solutions may be interpreted as magnetic branes. We study the singularity condition and find a nonsingular spacetime with a conical geometry. We also investigate the effects of different parameters on the deficit angle of spacetime near the origin. (orig.)
Signatures of topological superconductivity
Energy Technology Data Exchange (ETDEWEB)
Peng, Yang
2017-07-19
The prediction and experimental discovery of topological insulators brought the importance of topology in condensed matter physics into the limelight. Topology hence acts as a new dimension along which more and more new states of matter start to emerge. One of these topological states of matter, namely topological superconductors, comes into the focus because of their gapless excitations. These gapless excitations, especially in one dimensional topological superconductors, are Majorana zero modes localized at the ends of the superconductor and exhibit exotic nonabelian statistics, which can be potentially applied to fault-tolerant quantum computation. Given their highly interesting physical properties and potential applications to quantum computation, both theorists and experimentalists spend great efforts to realize topological supercondoctors and to detect Majoranas. In two projects within this thesis, we investigate the properties of Majorana zero modes in realistic materials which are absent in simple theoretical models. We find that the superconducting proximity effect, an essential ingredient in all existing platforms for topological superconductors, plays a significant role in determining the localization property of the Majoranas. Strong proximity coupling between the normal system and the superconducting substrate can lead to strongly localized Majoranas, which can explain the observation in a recent experiment. Motivated by experiments in Molenkamp's group, we also look at realistic quantum spin Hall Josephson junctions, in which charge puddles acting as magnetic impurities are coupled to the helical edge states. We find that with this setup, the junction generically realizes an exotic 8π periodic Josephson effect, which is absent in a pristine Josephson junction. In another two projects, we propose more pronounced signatures of Majoranas that are accessible with current experimental techniques. The first one is a transport measurement, which uses
Flegg, H Graham
2001-01-01
This excellent introduction to topology eases first-year math students and general readers into the subject by surveying its concepts in a descriptive and intuitive way, attempting to build a bridge from the familiar concepts of geometry to the formalized study of topology. The first three chapters focus on congruence classes defined by transformations in real Euclidean space. As the number of permitted transformations increases, these classes become larger, and their common topological properties become intuitively clear. Chapters 4-12 give a largely intuitive presentation of selected topics.
Sacramento, P. D.; Vieira, V. R.
2018-04-01
Mappings between models may be obtained by unitary transformations with preservation of the spectra but in general a change in the states. Non-canonical transformations in general also change the statistics of the operators involved. In these cases one may expect a change of topological properties as a consequence of the mapping. Here we consider some dualities resulting from mappings, by systematically using a Majorana fermion representation of spin and fermionic problems. We focus on the change of topological invariants that results from unitary transformations taking as examples the mapping between a spin system and a topological superconductor, and between different fermionic systems.
Algebraic topology and concurrency
DEFF Research Database (Denmark)
Fajstrup, Lisbeth; Raussen, Martin; Goubault, Eric
2006-01-01
We show in this article that some concepts from homotopy theory, in algebraic topology,are relevant for studying concurrent programs. We exhibit a natural semantics of semaphore programs, based on partially ordered topological spaces, which are studied up to “elastic deformation” or homotopy...... differences between ordinary and directed homotopy through examples. We also relate the topological view to a combinatorial view of concurrent programs closer to transition systems, through the notion of a cubical set. Finally we apply some of these concepts to the proof of the safeness of a two...
Chatterjee, D
2007-01-01
About the Book: This book provides exposition of the subject both in its general and algebraic aspects. It deals with the notions of topological spaces, compactness, connectedness, completeness including metrizability and compactification, algebraic aspects of topological spaces through homotopy groups and homology groups. It begins with the basic notions of topological spaces but soon going beyond them reaches the domain of algebra through the notions of homotopy, homology and cohomology. How these approaches work in harmony is the subject matter of this book. The book finally arrives at the
Topological pregauge-pregeometry
International Nuclear Information System (INIS)
Akama, Keiichi; Oda, Ichiro.
1990-12-01
The pregauge-pregeometric action, i.e. the fundamental matter action whose quantum fluctuations give rise to the Einstein-Hilbert and the Yang-Mills actions is investigated from the viewpoint of the topological field theory. We show that the scalar pregauge-pregeometric action is a topological invariant for appropriate choices of the internal gauge group. This model realizes the picture that the gravitational and internal gauge theory at the low energy scale is induced as the quantum effects of the topological field theory at the Planck scale. (author)
Elementary topology problem textbook
Viro, O Ya; Netsvetaev, N Yu; Kharlamov, V M
2008-01-01
This textbook on elementary topology contains a detailed introduction to general topology and an introduction to algebraic topology via its most classical and elementary segment centered at the notions of fundamental group and covering space. The book is tailored for the reader who is determined to work actively. The proofs of theorems are separated from their formulations and are gathered at the end of each chapter. This makes the book look like a pure problem book and encourages the reader to think through each formulation. A reader who prefers a more traditional style can either find the pr
Radiology in massive hemoptysis
International Nuclear Information System (INIS)
Marini, M.; Castro, J.M.; Gayol, A.; Aguilera, C.; Blanco, M.; Beraza, A.; Torres, J.
1995-01-01
We have reviewed our experience in diseases involving massive hemoptysis, systematizing the most common causes which include tuberculosis, bronchiectasis and cancer of the lung. Other less frequent causes, such as arteriovenous fistula, Aspergilloma, aneurysm, etc.; are also evaluated, and the most demonstrative images of each produced by the most precise imaging methods for their assessment are presented
Update on massive transfusion.
Pham, H P; Shaz, B H
2013-12-01
Massive haemorrhage requires massive transfusion (MT) to maintain adequate circulation and haemostasis. For optimal management of massively bleeding patients, regardless of aetiology (trauma, obstetrical, surgical), effective preparation and communication between transfusion and other laboratory services and clinical teams are essential. A well-defined MT protocol is a valuable tool to delineate how blood products are ordered, prepared, and delivered; determine laboratory algorithms to use as transfusion guidelines; and outline duties and facilitate communication between involved personnel. In MT patients, it is crucial to practice damage control resuscitation and to administer blood products early in the resuscitation. Trauma patients are often admitted with early trauma-induced coagulopathy (ETIC), which is associated with mortality; the aetiology of ETIC is likely multifactorial. Current data support that trauma patients treated with higher ratios of plasma and platelet to red blood cell transfusions have improved outcomes, but further clinical investigation is needed. Additionally, tranexamic acid has been shown to decrease the mortality in trauma patients requiring MT. Greater use of cryoprecipitate or fibrinogen concentrate might be beneficial in MT patients from obstetrical causes. The risks and benefits for other therapies (prothrombin complex concentrate, recombinant activated factor VII, or whole blood) are not clearly defined in MT patients. Throughout the resuscitation, the patient should be closely monitored and both metabolic and coagulation abnormalities corrected. Further studies are needed to clarify the optimal ratios of blood products, treatment based on underlying clinical disorder, use of alternative therapies, and integration of laboratory testing results in the management of massively bleeding patients.
Massive antenatal fetomaternal hemorrhage
DEFF Research Database (Denmark)
Dziegiel, Morten Hanefeld; Koldkjaer, Ole; Berkowicz, Adela
2005-01-01
Massive fetomaternal hemorrhage (FMH) can lead to life-threatening anemia. Quantification based on flow cytometry with anti-hemoglobin F (HbF) is applicable in all cases but underestimation of large fetal bleeds has been reported. A large FMH from an ABO-compatible fetus allows an estimation...
Topology optimized microbioreactors
DEFF Research Database (Denmark)
Schäpper, Daniel; Lencastre Fernandes, Rita; Eliasson Lantz, Anna
2011-01-01
This article presents the fusion of two hitherto unrelated fields—microbioreactors and topology optimization. The basis for this study is a rectangular microbioreactor with homogeneously distributed immobilized brewers yeast cells (Saccharomyces cerevisiae) that produce a recombinant protein...
Real topological string amplitudes
Energy Technology Data Exchange (ETDEWEB)
Narain, K.S. [The Abdus Salam International Centre for Theoretical Physics (ICTP),Strada Costiera 11, Trieste, 34151 (Italy); Piazzalunga, N. [Simons Center for Geometry and Physics, State University of New York,Stony Brook, NY, 11794-3636 (United States); International School for Advanced Studies (SISSA) and INFN, Sez. di Trieste,via Bonomea 265, Trieste, 34136 (Italy); Tanzini, A. [International School for Advanced Studies (SISSA) and INFN, Sez. di Trieste,via Bonomea 265, Trieste, 34136 (Italy)
2017-03-15
We discuss the physical superstring correlation functions in type I theory (or equivalently type II with orientifold) that compute real topological string amplitudes. We consider the correlator corresponding to holomorphic derivative of the real topological amplitude G{sub χ}, at fixed worldsheet Euler characteristic χ. This corresponds in the low-energy effective action to N=2 Weyl multiplet, appropriately reduced to the orientifold invariant part, and raised to the power g{sup ′}=−χ+1. We show that the physical string correlator gives precisely the holomorphic derivative of topological amplitude. Finally, we apply this method to the standard closed oriented case as well, and prove a similar statement for the topological amplitude F{sub g}.
Topological Susceptibility from Slabs
Bietenholz, Wolfgang; Gerber, Urs
2015-01-01
In quantum field theories with topological sectors, a non-perturbative quantity of interest is the topological susceptibility chi_t. In principle it seems straightforward to measure chi_t by means of Monte Carlo simulations. However, for local update algorithms and fine lattice spacings, this tends to be difficult, since the Monte Carlo history rarely changes the topological sector. Here we test a method to measure chi_t even if data from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as slabs. Assuming a Gaussian distribution of these charges, this method enables the evaluation of chi_t, as we demonstrate with numerical results for non-linear sigma-models.
Topological susceptibility from slabs
Energy Technology Data Exchange (ETDEWEB)
Bietenholz, Wolfgang [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543, Distrito Federal, C.P. 04510 (Mexico); Forcrand, Philippe de [Institute for Theoretical Physics, ETH Zürich,CH-8093 Zürich (Switzerland); CERN, Physics Department, TH Unit, CH-1211 Geneva 23 (Switzerland); Gerber, Urs [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, A.P. 70-543, Distrito Federal, C.P. 04510 (Mexico); Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo,Edificio C-3, Apdo. Postal 2-82, Morelia, Michoacán, C.P. 58040 (Mexico)
2015-12-14
In quantum field theories with topological sectors, a non-perturbative quantity of interest is the topological susceptibility χ{sub t}. In principle it seems straightforward to measure χ{sub t} by means of Monte Carlo simulations. However, for local update algorithms and fine lattice spacings, this tends to be difficult, since the Monte Carlo history rarely changes the topological sector. Here we test a method to measure χ{sub t} even if data from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as slabs. Assuming a Gaussian distribution of these charges, this method enables the evaluation of χ{sub t}, as we demonstrate with numerical results for non-linear σ-models.
Contact and symplectic topology
Colin, Vincent; Stipsicz, András
2014-01-01
Symplectic and contact geometry naturally emerged from the mathematical description of classical physics. The discovery of new rigidity phenomena and properties satisfied by these geometric structures launched a new research field worldwide. The intense activity of many European research groups in this field is reflected by the ESF Research Networking Programme "Contact And Symplectic Topology" (CAST). The lectures of the Summer School in Nantes (June 2011) and of the CAST Summer School in Budapest (July 2012) provide a nice panorama of many aspects of the present status of contact and symplectic topology. The notes of the minicourses offer a gentle introduction to topics which have developed in an amazing speed in the recent past. These topics include 3-dimensional and higher dimensional contact topology, Fukaya categories, asymptotically holomorphic methods in contact topology, bordered Floer homology, embedded contact homology, and flexibility results for Stein manifolds.
Wilansky, Albert
2008-01-01
Three levels of examples and problems make this volume appropriate for students and professionals. Abundant exercises, ordered and numbered by degree of difficulty, illustrate important topological concepts. 1970 edition.
Fall Foliage Topology Seminars
1990-01-01
This book demonstrates the lively interaction between algebraic topology, very low dimensional topology and combinatorial group theory. Many of the ideas presented are still in their infancy, and it is hoped that the work here will spur others to new and exciting developments. Among the many techniques disussed are the use of obstruction groups to distinguish certain exact sequences and several graph theoretic techniques with applications to the theory of groups.
Inoue, Tsuyoshi; Hennebelle, Patrick; Fukui, Yasuo; Matsumoto, Tomoaki; Iwasaki, Kazunari; Inutsuka, Shu-ichiro
2018-05-01
Recent observations suggest an that intensive molecular cloud collision can trigger massive star/cluster formation. The most important physical process caused by the collision is a shock compression. In this paper, the influence of a shock wave on the evolution of a molecular cloud is studied numerically by using isothermal magnetohydrodynamics simulations with the effect of self-gravity. Adaptive mesh refinement and sink particle techniques are used to follow the long-time evolution of the shocked cloud. We find that the shock compression of a turbulent inhomogeneous molecular cloud creates massive filaments, which lie perpendicularly to the background magnetic field, as we have pointed out in a previous paper. The massive filament shows global collapse along the filament, which feeds a sink particle located at the collapse center. We observe a high accretion rate \\dot{M}_acc> 10^{-4} M_{⊙}yr-1 that is high enough to allow the formation of even O-type stars. The most massive sink particle achieves M > 50 M_{⊙} in a few times 105 yr after the onset of the filament collapse.
International Nuclear Information System (INIS)
Ne'eman, Y.
1998-01-01
The relatively simple Fibre-Bundle geometry of a Yang-Mills gauge theory - mainly the clear distinction between base and fibre - made it possible, between 1953 and 1971, to construct a fully quantized version and prove that theory's renormalizability; moreover, nonperturbative (topological) solutions were subsequently found in both the fully symmetric and the spontaneously broken modes (instantons, monopoles). Though originally constructed as a model formalism, it became in 1974 the mathematical mold holding the entire Standard Model (i.e. QCD and the Electroweak theory). On the other hand, between 1974 and 1984, Einstein's theory was shown to be perturbatively nonrenormalizable. Since 1974, the search for Quantum Gravity has therefore provided the main motivation for the construction of Gauge Theories of Gravity. Earlier, however, in 1958-76 several such attempts were initiated, for aesthetic or heuristic reasons, to provide a better understanding of the algebraic structure of GR. A third motivation has come from the interest in Unification, making it necessary to bring GR into a form compatible with an enlargement of the Standard Model. Models can be classified according to the relevant structure group in the fibre. Within the Poincare group, this has been either the R 4 translations, or the Lorentz group SL(2, C) - or the entire Poincare SL(2, C) x R 4 . Enlarging the group has involved the use of the Conformal SU(2, 2), the special Affine SA(4, R) = SL(4, R) x R 4 or Affine A(4, R) groups. Supergroups have included supersymmetry, i.e. the graded-Poincare group (n =1...8 m its extensions) or the superconformal SU(2, 2/n). These supergravity theories have exploited the lessons of the aesthetic-heuristic models - Einstein-Cartan etc. - and also achieved the Unification target. Although perturbative renormalizability has been achieved in some models, whether they satisfy unitarity is not known. The nonperturbative Ashtekar program has exploited the understanding of
Tunable Topological Phononic Crystals
Chen, Zeguo; Wu, Ying
2016-01-01
Topological insulators first observed in electronic systems have inspired many analogues in photonic and phononic crystals in which remarkable one-way propagation edge states are supported by topologically nontrivial band gaps. Such band gaps can be achieved by breaking the time-reversal symmetry to lift the degeneracy associated with Dirac cones at the corners of the Brillouin zone. Here, we report on our construction of a phononic crystal exhibiting a Dirac-like cone in the Brillouin zone center. We demonstrate that simultaneously breaking the time-reversal symmetry and altering the geometric size of the unit cell result in a topological transition that we verify by the Chern number calculation and edge-mode analysis. We develop a complete model based on the tight binding to uncover the physical mechanisms of the topological transition. Both the model and numerical simulations show that the topology of the band gap is tunable by varying both the velocity field and the geometric size; such tunability may dramatically enrich the design and use of acoustic topological insulators.
Tunable Topological Phononic Crystals
Chen, Zeguo
2016-05-27
Topological insulators first observed in electronic systems have inspired many analogues in photonic and phononic crystals in which remarkable one-way propagation edge states are supported by topologically nontrivial band gaps. Such band gaps can be achieved by breaking the time-reversal symmetry to lift the degeneracy associated with Dirac cones at the corners of the Brillouin zone. Here, we report on our construction of a phononic crystal exhibiting a Dirac-like cone in the Brillouin zone center. We demonstrate that simultaneously breaking the time-reversal symmetry and altering the geometric size of the unit cell result in a topological transition that we verify by the Chern number calculation and edge-mode analysis. We develop a complete model based on the tight binding to uncover the physical mechanisms of the topological transition. Both the model and numerical simulations show that the topology of the band gap is tunable by varying both the velocity field and the geometric size; such tunability may dramatically enrich the design and use of acoustic topological insulators.
Chiral gravity, log gravity, and extremal CFT
International Nuclear Information System (INIS)
Maloney, Alexander; Song Wei; Strominger, Andrew
2010-01-01
We show that the linearization of all exact solutions of classical chiral gravity around the AdS 3 vacuum have positive energy. Nonchiral and negative-energy solutions of the linearized equations are infrared divergent at second order, and so are removed from the spectrum. In other words, chirality is confined and the equations of motion have linearization instabilities. We prove that the only stationary, axially symmetric solutions of chiral gravity are BTZ black holes, which have positive energy. It is further shown that classical log gravity--the theory with logarithmically relaxed boundary conditions--has finite asymptotic symmetry generators but is not chiral and hence may be dual at the quantum level to a logarithmic conformal field theories (CFT). Moreover we show that log gravity contains chiral gravity within it as a decoupled charge superselection sector. We formally evaluate the Euclidean sum over geometries of chiral gravity and show that it gives precisely the holomorphic extremal CFT partition function. The modular invariance and integrality of the expansion coefficients of this partition function are consistent with the existence of an exact quantum theory of chiral gravity. We argue that the problem of quantizing chiral gravity is the holographic dual of the problem of constructing an extremal CFT, while quantizing log gravity is dual to the problem of constructing a logarithmic extremal CFT.
Massive propagators in instanton fields
International Nuclear Information System (INIS)
Brown, L.S.; Lee, C.
1978-01-01
Green's functions for massive spinor and vector particles propagating in a self-dual but otherwise arbitrary non-Abelian gauge field are shown to be completely determined by the corresponding Green's functions of massive scalar particles
Knots, topology and quantum field theories
International Nuclear Information System (INIS)
Lusanna, L.
1989-01-01
The title of the workshop, Knots, Topology and Quantum Field Theory, accurate reflected the topics discussed. There have been important developments in mathematical and quantum field theory in the past few years, which had a large impact on physicist thinking. It is historically unusual and pleasing that these developments are taking place as a result of an intense interaction between mathematical physicists and mathematician. On the one hand, topological concepts and methods are playing an increasingly important lead to novel mathematical concepts: for instance, the study of quantum groups open a new chapter in the deformation theory of Lie algebras. These developments at present will lead to new insights into the theory of elementary particles and their interactions. In essence, the talks dealt with three, broadly defined areas of theoretical physics. One was topological quantum field theories, the other the problem of quantum groups and the third one certain aspects of more traditional field theories, such as, for instance, quantum gravity. These topics, however, are interrelated and the general theme of the workshop defies rigid classification; this was evident from the cross references to be found in almo all the talks
Energy Technology Data Exchange (ETDEWEB)
Bourget, Antoine [Department of Physics, Universidad de Oviedo, Avenida Calvo Sotelo 18, 33007 Oviedo (Spain); Troost, Jan [Laboratoire de Physique Théorique de l’É cole Normale Supérieure, CNRS,PSL Research University, Sorbonne Universités, 75005 Paris (France)
2017-05-09
We discuss the permutation group G of massive vacua of four-dimensional gauge theories with N=1 supersymmetry that arises upon tracing loops in the space of couplings. We concentrate on superconformal N=4 and N=2 theories with N=1 supersymmetry preserving mass deformations. The permutation group G of massive vacua is the Galois group of characteristic polynomials for the vacuum expectation values of chiral observables. We provide various techniques to effectively compute characteristic polynomials in given theories, and we deduce the existence of varying symmetry breaking patterns of the duality group depending on the gauge algebra and matter content of the theory. Our examples give rise to interesting field extensions of spaces of modular forms.
International Nuclear Information System (INIS)
Humphreys, R.M.
1987-01-01
The relationship between the morphologic type of a galaxy and the evolution of its massive stars is explored, reviewing observational results for nearby galaxies. The data are presented in diagrams, and it is found that the massive-star populations of most Sc spiral galaxies and irregular galaxies are similar, while those of Sb spirals such as M 31 and M 81 may be affected by morphology (via differences in the initial mass function or star-formation rate). Consideration is also given to the stability-related upper luminosity limit in the H-R diagram of hypergiant stars (attributed to radiation pressure in hot stars and turbulence in cool stars) and the goals of future observation campaigns. 88 references
Directory of Open Access Journals (Sweden)
Tharindu Rekha Liyanagunawardena
2015-01-01
Full Text Available Massive Open Online Courses (MOOCs are a new addition to the open educational provision. They are offered mainly by prestigious universities on various commercial and non-commercial MOOC platforms allowing anyone who is interested to experience the world class teaching practiced in these universities. MOOCs have attracted wide interest from around the world. However, learner demographics in MOOCs suggest that some demographic groups are underrepresented. At present MOOCs seem to be better serving the continuous professional development sector.
International Nuclear Information System (INIS)
Loore, C. de
1984-01-01
The evolution of stars with masses larger than 15 sun masses is reviewed. These stars have large convective cores and lose a substantial fraction of their matter by stellar wind. The treatment of convection and the parameterisation of the stellar wind mass loss are analysed within the context of existing disagreements between theory and observation. The evolution of massive close binaries and the origin of Wolf-Rayet Stars and X-ray binaries is also sketched. (author)
Countable Fuzzy Topological Space and Countable Fuzzy Topological Vector Space
Directory of Open Access Journals (Sweden)
Apu Kumar Saha
2015-06-01
Full Text Available This paper deals with countable fuzzy topological spaces, a generalization of the notion of fuzzy topological spaces. A collection of fuzzy sets F on a universe X forms a countable fuzzy topology if in the definition of a fuzzy topology, the condition of arbitrary supremum is relaxed to countable supremum. In this generalized fuzzy structure, the continuity of fuzzy functions and some other related properties are studied. Also the class of countable fuzzy topological vector spaces as a generalization of the class of fuzzy topological vector spaces has been introduced and investigated.
International Nuclear Information System (INIS)
Schoutens, K.; van Nieuwenhuizen, P.; State Univ. of New York, Stony Brook, NY
1991-11-01
We briefly review some results in the theory of quantum W 3 gravity in the chiral gauge. We compare them with similar results in the analogous but simpler cases of d = 2 induced gauge theories and d = 2 induced gravity
... medlineplus.gov/ency/article/003587.htm Urine specific gravity test To use the sharing features on this page, please enable JavaScript. Urine specific gravity is a laboratory test that shows the concentration ...
Cadiz, California Gravity Data
National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (32 records) were gathered by Mr. Seth I. Gutman for AridTech Inc., Denver, Colorado using a Worden Prospector gravity meter. This data base...
National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...
National Oceanic and Atmospheric Administration, Department of Commerce — The Decade of North American Geology (DNAG) gravity grid values, spaced at 6 km, were used to produce the Gravity Anomaly Map of North America (1987; scale...
International Nuclear Information System (INIS)
Pinheiro, R.
1979-01-01
The properties and production of gravitational radiation are described. The prospects for their detection are considered including the Weber apparatus and gravity-wave telescopes. Possibilities of gravity-wave astronomy are noted
Northern Oklahoma Gravity Data
National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (710 records) were compiled by Professor Ahern. This data base was received in June 1992. Principal gravity parameters include latitude,...
National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (24,284 records) were compiled by the U. S. Geological Survey. This data base was received on February 23, 1993. Principal gravity...
International Nuclear Information System (INIS)
Vega, H.J. de
1990-01-01
One of the main challenges in theoretical physics today is the unification of all interactions including gravity. At present, string theories appear as the most promising candidates to achieve such a unification. However, gravity has not completely been incorporated in string theory, many technical and conceptual problems remain and a full quantum theory of gravity is still non-existent. Our aim is to properly understand strings in the context of quantum gravity. Attempts towards this are reviewed. (author)
LHCb Topological Trigger Reoptimization
International Nuclear Information System (INIS)
Likhomanenko, Tatiana; Khairullin, Egor; Rogozhnikov, Alex; Ustyuzhanin, Andrey; Ilten, Philip; Williams, Michael
2015-01-01
The main b-physics trigger algorithm used by the LHCb experiment is the so- called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger, which utilized a custom boosted decision tree algorithm, selected a nearly 100% pure sample of b-hadrons with a typical efficiency of 60-70%; its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and neural networks. The topological trigger algorithm is designed to select all ’interesting” decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. Methods studied include cascading, ensembling and blending techniques. Furthermore, novel boosting techniques have been implemented that will help reduce systematic uncertainties in Run 2 measurements. We demonstrate that the reoptimized topological trigger is expected to significantly improve on the Run 1 performance for a wide range of b-hadron decays. (paper)
p-topological Cauchy completions
Directory of Open Access Journals (Sweden)
J. Wig
1999-01-01
Full Text Available The duality between “regular” and “topological” as convergence space properties extends in a natural way to the more general properties “p-regular” and “p-topological.” Since earlier papers have investigated regular, p-regular, and topological Cauchy completions, we hereby initiate a study of p-topological Cauchy completions. A p-topological Cauchy space has a p-topological completion if and only if it is “cushioned,” meaning that each equivalence class of nonconvergent Cauchy filters contains a smallest filter. For a Cauchy space allowing a p-topological completion, it is shown that a certain class of Reed completions preserve the p-topological property, including the Wyler and Kowalsky completions, which are, respectively, the finest and the coarsest p-topological completions. However, not all p-topological completions are Reed completions. Several extension theorems for p-topological completions are obtained. The most interesting of these states that any Cauchy-continuous map between Cauchy spaces allowing p-topological and p′-topological completions, respectively, can always be extended to a θ-continuous map between any p-topological completion of the first space and any p′-topological completion of the second.
Relativistic theory of gravity
International Nuclear Information System (INIS)
Logunov, A.A.; Mestvirishvili, M.A.
1985-01-01
This work presents an unambiguous construction of the relativistic theory of gravity (RTG) in the framework of relativity and the geometrization principle. The gauge principle has been formulated, and the Lagrangian density of the gravitational field has thus been constructed. This theory explains the totality of the available experimental data on the solar system and predicts the existence of gravitational waves of the Faraday-Maxwell type. According to the RTG, the Universe is infinite and ''flat'', hence it follows that its matter density should be equal to its critical density. Therefore, an appreciable ''hidden mass'' exceeding the presently observed mass of the matter almost 40-fold should exist in the Universe in some form of the matter or other. In accordance with the RTG, a massive body having a finite density ceases to contract under gravitational forces within a finite interval of proper time. From the viewpoint of an external reference frame, the brightness of the body decreases exponentially (it is getting darker), but nothing extraordinary happens in this case because its density always remains finite and, for example, for a body with the mass of about 10 8 M 0 it is equal to 2 g/cm 3 . That is why it follows from the RTG that there could be no object whatsoever (black holes) in which gravitational collapse of matter develops to an infinite density. As has been shown, the presence of a cosmological term necessarily requires the introduction of a term with an explicit dependence on the Minkowski metrics. For the long-range gravitational forces the cosmological constant vanishes
International Nuclear Information System (INIS)
La, H.
1992-01-01
A new geometric formulation of Liouville gravity based on the area preserving diffeo-morphism is given and a possible alternative to reinterpret Liouville gravity is suggested, namely, a scalar field coupled to two-dimensional gravity with a curvature constraint
Bergshoeff, E.; Pope, C.N.; Stelle, K.S.
1990-01-01
We discuss the notion of higher-spin covariance in w∞ gravity. We show how a recently proposed covariant w∞ gravity action can be obtained from non-chiral w∞ gravity by making field redefinitions that introduce new gauge-field components with corresponding new gauge transformations.
Induced quantum conformal gravity
International Nuclear Information System (INIS)
Novozhilov, Y.V.; Vassilevich, D.V.
1988-11-01
Quantum gravity is considered as induced by matter degrees of freedom and related to the symmetry breakdown in the low energy region of a non-Abelian gauge theory of fundamental fields. An effective action for quantum conformal gravity is derived where both the gravitational constant and conformal kinetic term are positive. Relation with induced classical gravity is established. (author). 15 refs
Amelino-Camelia, Giovanni
2003-01-01
Comment: 9 pages, LaTex. These notes were prepared while working on an invited contribution to the November 2003 issue of Physics World, which focused on quantum gravity. They intend to give a non-technical introduction (accessible to readers from outside quantum gravity) to "Quantum Gravity Phenomenology"
MacKeown, P. K.
1984-01-01
Clarifies two concepts of gravity--those of a fictitious force and those of how space and time may have geometry. Reviews the position of Newton's theory of gravity in the context of special relativity and considers why gravity (as distinct from electromagnetics) lends itself to Einstein's revolutionary interpretation. (JN)
η' → γγ and the topological susceptibility
International Nuclear Information System (INIS)
Shore, G.M.
2000-01-01
The radiative decays η'(η) → γγ are discussed. The modifications of the conventional PCAC formulae due to the gluonic contribution to the flavour singlet axial anomaly are given. The decay constants satisfy a modified Dashen formula which generalises the Witten Veneziano formula for the mass of the η'. It is shown how the topological susceptibility in QCD with massive, dynamical quarks may be extracted from measurements of η'(η) → γγ
Spherical collapse and cluster counts in modified gravity models
International Nuclear Information System (INIS)
Martino, Matthew C.; Stabenau, Hans F.; Sheth, Ravi K.
2009-01-01
Modifications to the gravitational potential affect the nonlinear gravitational evolution of large scale structures in the Universe. To illustrate some generic features of such changes, we study the evolution of spherically symmetric perturbations when the modification is of Yukawa type; this is nontrivial, because we should not and do not assume that Birkhoff's theorem applies. We then show how to estimate the abundance of virialized objects in such models. Comparison with numerical simulations shows reasonable agreement: When normalized to have the same fluctuations at early times, weaker large scale gravity produces fewer massive halos. However, the opposite can be true for models that are normalized to have the same linear theory power spectrum today, so the abundance of rich clusters potentially places interesting constraints on such models. Our analysis also indicates that the formation histories and abundances of sufficiently low mass objects are unchanged from standard gravity. This explains why simulations have found that the nonlinear power spectrum at large k is unaffected by such modifications to the gravitational potential. In addition, the most massive objects in models with normalized cosmic microwave background and weaker gravity are expected to be similar to the high-redshift progenitors of the most massive objects in models with stronger gravity. Thus, the difference between the cluster and field galaxy populations is expected to be larger in models with stronger large scale gravity.
A Massive-born Neutron Star with a Massive White Dwarf Companion
Energy Technology Data Exchange (ETDEWEB)
Cognard, Ismaël; Guillemot, Lucas; Theureau, Gilles [Laboratoire de Physique et Chimie de l’Environnement et de l’Espace, Université d’Orléans/CNRS, F-45071 Orléans Cedex 02 (France); Freire, Paulo C. C. [Station de radioastronomie de Nançay, Observatoire de Paris, CNRS/INSU, F-18330 Nançay (France); Tauris, Thomas M.; Wex, Norbert; Graikou, Eleni; Kramer, Michael; Desvignes, Gregory; Lazarus, Patrick [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Stappers, Benjamin; Lyne, Andrew G. [Jodrell Bank Center for Astrophysics, School of Physics and Astronomy, The University of Manchester, M13 9PL (United Kingdom); Bassa, Cees [ASTRON, The Netherlands Institute for Radioastronomy, Postbus 2, 7900 AA, Dwingeloo (Netherlands)
2017-08-01
We report on the results of a 4 year timing campaign of PSR J2222−0137, a 2.44 day binary pulsar with a massive white dwarf (WD) companion, with the Nançay, Effelsberg, and Lovell radio telescopes. Using the Shapiro delay for this system, we find a pulsar mass m {sub p} = 1.76 ± 0.06 M {sub ⊙} and a WD mass m {sub c} = 1.293 ± 0.025 M {sub ⊙}. We also measure the rate of advance of periastron for this system, which is marginally consistent with the general relativity prediction for these masses. The short lifetime of the massive WD progenitor star led to a rapid X-ray binary phase with little (< 10{sup −2} M {sub ⊙}) mass accretion onto the neutron star; hence, the current pulsar mass is, within uncertainties, its birth mass, which is the largest measured to date. We discuss the discrepancy with previous mass measurements for this system; we conclude that the measurements presented here are likely to be more accurate. Finally, we highlight the usefulness of this system for testing alternative theories of gravity by tightly constraining the presence of dipolar radiation. This is of particular importance for certain aspects of strong-field gravity, like spontaneous scalarization, since the mass of PSR J2222−0137 puts that system into a poorly tested parameter range.
Manufacturing tolerant topology optimization
DEFF Research Database (Denmark)
Sigmund, Ole
2009-01-01
In this paper we present an extension of the topology optimization method to include uncertainties during the fabrication of macro, micro and nano structures. More specifically, we consider devices that are manufactured using processes which may result in (uniformly) too thin (eroded) or too thick...... (dilated) structures compared to the intended topology. Examples are MEMS devices manufactured using etching processes, nano-devices manufactured using e-beam lithography or laser micro-machining and macro structures manufactured using milling processes. In the suggested robust topology optimization...... approach, under- and over-etching is modelled by image processing-based "erode" and "dilate" operators and the optimization problem is formulated as a worst case design problem. Applications of the method to the design of macro structures for minimum compliance and micro compliant mechanisms show...
Aganagic, M; Marino, M; Vafa, C; Aganagic, Mina; Klemm, Albrecht; Marino, Marcos; Vafa, Cumrun
2005-01-01
We construct a cubic field theory which provides all genus amplitudes of the topological A-model for all non-compact Calabi-Yau toric threefolds. The topology of a given Feynman diagram encodes the topology of a fixed Calabi-Yau, with Schwinger parameters playing the role of Kahler classes of Calabi-Yau. We interpret this result as an operator computation of the amplitudes in the B-model mirror which is the Kodaira-Spencer quantum theory. The only degree of freedom of this theory is an unconventional chiral scalar on a Riemann surface. In this setup we identify the B-branes on the mirror Riemann surface as fermions related to the chiral boson by bosonization.
Riemann, topology, and physics
Monastyrsky, Michael I
2008-01-01
This significantly expanded second edition of Riemann, Topology, and Physics combines a fascinating account of the life and work of Bernhard Riemann with a lucid discussion of current interaction between topology and physics. The author, a distinguished mathematical physicist, takes into account his own research at the Riemann archives of Göttingen University and developments over the last decade that connect Riemann with numerous significant ideas and methods reflected throughout contemporary mathematics and physics. Special attention is paid in part one to results on the Riemann–Hilbert problem and, in part two, to discoveries in field theory and condensed matter such as the quantum Hall effect, quasicrystals, membranes with nontrivial topology, "fake" differential structures on 4-dimensional Euclidean space, new invariants of knots and more. In his relatively short lifetime, this great mathematician made outstanding contributions to nearly all branches of mathematics; today Riemann’s name appears prom...
International Nuclear Information System (INIS)
Zou, L.P.; Zhang, P.M.; Pak, D.G.
2013-01-01
We consider topological structure of classical vacuum solutions in quantum chromodynamics. Topologically non-equivalent vacuum configurations are classified by non-trivial second and third homotopy groups for coset of the color group SU(N) (N=2,3) under the action of maximal Abelian stability group. Starting with explicit vacuum knot configurations we study possible exact classical solutions. Exact analytic non-static knot solution in a simple CP 1 model in Euclidean space–time has been obtained. We construct an ansatz based on knot and monopole topological vacuum structure for searching new solutions in SU(2) and SU(3) QCD. We show that singular knot-like solutions in QCD in Minkowski space–time can be naturally obtained from knot solitons in integrable CP 1 models. A family of Skyrme type low energy effective theories of QCD admitting exact analytic solutions with non-vanishing Hopf charge is proposed
Sadun, Lorenzo
2008-01-01
Aperiodic tilings are interesting to mathematicians and scientists for both theoretical and practical reasons. The serious study of aperiodic tilings began as a solution to a problem in logic. Simpler aperiodic tilings eventually revealed hidden "symmetries" that were previously considered impossible, while the tilings themselves were quite striking. The discovery of quasicrystals showed that such aperiodicity actually occurs in nature and led to advances in materials science. Many properties of aperiodic tilings can be discerned by studying one tiling at a time. However, by studying families of tilings, further properties are revealed. This broader study naturally leads to the topology of tiling spaces. This book is an introduction to the topology of tiling spaces, with a target audience of graduate students who wish to learn about the interface of topology with aperiodic order. It isn't a comprehensive and cross-referenced tome about everything having to do with tilings, which would be too big, too hard to ...
Topology, calculus and approximation
Komornik, Vilmos
2017-01-01
Presenting basic results of topology, calculus of several variables, and approximation theory which are rarely treated in a single volume, this textbook includes several beautiful, but almost forgotten, classical theorems of Descartes, Erdős, Fejér, Stieltjes, and Turán. The exposition style of Topology, Calculus and Approximation follows the Hungarian mathematical tradition of Paul Erdős and others. In the first part, the classical results of Alexandroff, Cantor, Hausdorff, Helly, Peano, Radon, Tietze and Urysohn illustrate the theories of metric, topological and normed spaces. Following this, the general framework of normed spaces and Carathéodory's definition of the derivative are shown to simplify the statement and proof of various theorems in calculus and ordinary differential equations. The third and final part is devoted to interpolation, orthogonal polynomials, numerical integration, asymptotic expansions and the numerical solution of algebraic and differential equations. Students of both pure an...
Deo, Satya
2018-01-01
This book presents the first concepts of the topics in algebraic topology such as the general simplicial complexes, simplicial homology theory, fundamental groups, covering spaces and singular homology theory in greater detail. Originally published in 2003, this book has become one of the seminal books. Now, in the completely revised and enlarged edition, the book discusses the rapidly developing field of algebraic topology. Targeted to undergraduate and graduate students of mathematics, the prerequisite for this book is minimal knowledge of linear algebra, group theory and topological spaces. The book discusses about the relevant concepts and ideas in a very lucid manner, providing suitable motivations and illustrations. All relevant topics are covered, including the classical theorems like the Brouwer’s fixed point theorem, Lefschetz fixed point theorem, Borsuk-Ulam theorem, Brouwer’s separation theorem and the theorem on invariance of the domain. Most of the exercises are elementary, but sometimes chal...
Topological and non-topological soliton solutions to some time
Indian Academy of Sciences (India)
Topological and non-topological soliton solutions to some time-fractional differential equations ... These equations have been widely applied in many branches of nonlinear ... Department of Engineering Sciences, Faculty of Technology and ...
New topological theories and conjugacy classes of the Weyl group
International Nuclear Information System (INIS)
Hollowood, T.J.; Miramontes, J.L.
1993-01-01
The problem of interpreting a set of W-algebra constraints constructed in terms of an arbitrarily twisted scalar field as recursion relations of some topological theory is addressed. In this picture, the models of topological gravity coupled to A, D or E topological matter, correspond to taking the scalar field twisted by the Coxeter element of the Weyl group. It turns out that not all conjugacy classes of the Weyl group lead to models which allow for such an interpretation. For example, it is shown that for the A algebras there are two possible choices for the conjugacy class, giving a new set of theories in addition to the conventional ones. Furthermore, it is shown how the new series of theories contains the conventional series as a subsector. A tentative interpretation of this new series in terms of intersection theory is presented. (orig.)
Particle creation and destruction of quantum coherence by topological change
International Nuclear Information System (INIS)
Lavrelashvili, G.V.; Rubakov, V.A.; Tinyakov, P.G.
1988-01-01
The possibility is considered that changes of spatial topology occur as tunneling events in quantum gravity. Creation of scalar and spinor particles during these tunneling transitions is studied. The relevant formalism based on the euclidean Schroedinger equation and coherent state representation is developed. This formalism is illustrated in a two-dimensional example. It is argued that the particle creation during the topological changes induces the loss of quantum coherence. The particle creation is calculated in the case of O(4)-invariant background euclidean four-dimensional metrics. This calculation is used for estimating the loss of quantum coherence. An upper limit on the rate of the topological changes, A -17 M 4 Pl , is derived from the observation of K 0 -anti K 0 oscillations. (orig.)
Dual descriptions of massive spin-2 particles in D=3+1
International Nuclear Information System (INIS)
Dalmazi, Denis
2013-01-01
Full text: Since the sixties (last century) one speculates on the effects of a possible (tiny) mass for the graviton. One expects a decrease in the gravitational interaction at large distances which comes handy regarding the experimental data of the last 15 years on the accelerated expansion of the universe. There has been a growing interest in massive quantum gravity in the last years. Almost all recent works are built up on the top of a free (quadratic) action for a massive spin-2 particle known as massive Fierz-Pauli (FP) theory which has first appeared in 1939. In this theory the basic field is a symmetric rank-2 tensor. It is a common belief in the massive gravity community that the massive FP theory is the unique self-consistent (ghost free, Poincare covariant, correct number of degrees of freedom) description of massive spin-2 particles in terms of a rank-2 tensor. We have shown recently that there are other possibilities if we start with a general (non-symmetric) rank-2 tensor. Here we show how our previous work is related with the well known massive FP theory via the introduction of spectators fields of rank-0 (scalar) and rank-1 (vector). We comment on the introduction of interacting vertices and how they affect the free duality with the massive FP theory (author)
International Nuclear Information System (INIS)
Carroll, S.M.; Trodden, M.
1998-01-01
We propose a class of field theories featuring solitonic solutions in which topological defects can end when they intersect other defects of equal or higher dimensionality. Such configurations may be termed open-quotes Dirichlet topological defects,close quotes in analogy with the D-branes of string theory. Our discussion focuses on defects in scalar field theories with either gauge or global symmetries, in 3+1 dimensions; the types of defects considered include walls ending on walls, strings on walls, and strings on strings. copyright 1998 The American Physical Society
Filters in topology optimization
DEFF Research Database (Denmark)
Bourdin, Blaise
1999-01-01
In this article, a modified (``filtered'') version of the minimum compliance topology optimization problem is studied. The direct dependence of the material properties on its pointwise density is replaced by a regularization of the density field using a convolution operator. In this setting...... it is possible to establish the existence of solutions. Moreover, convergence of an approximation by means of finite elements can be obtained. This is illustrated through some numerical experiments. The ``filtering'' technique is also shown to cope with two important numerical problems in topology optimization...
Kostov, Ivan
2010-01-01
We study the quasiclassical expansion associated with a complex curve. In a more specific context this is the 1/N expansion in U(N)-invariant matrix integrals. We compare two approaches, the CFT approach and the topological recursion, and show their equivalence. The CFT approach reformulates the problem in terms of a conformal field theory on a Riemann surface, while the topological recursion is based on a recurrence equation for the observables representing symplectic invariants on the complex curve. The two approaches lead to two different graph expansions, one of which can be obtained as a partial resummation of the other.
Coghetto Roland
2015-01-01
Using Mizar [9], and the formal topological space structure (FMT_Space_Str) [19], we introduce the three U-FMT conditions (U-FMT filter, U-FMT with point and U-FMT local) similar to those VI, VII, VIII and VIV of the proposition 2 in [10]: If to each element x of a set X there corresponds a set B(x) of subsets of X such that the properties VI, VII, VIII and VIV are satisfied, then there is a unique topological structure on X such that, for each x ∈ X, B(x) is the set of neighborhoods of x ...
Monastyrsky, M I
2006-01-01
This book reports new results in condensed matter physics for which topological methods and ideas are important. It considers, on the one hand, recently discovered systems such as carbon nanocrystals and, on the other hand, new topological methods used to describe more traditional systems such as the Fermi surfaces of normal metals, liquid crystals and quasicrystals. The authors of the book are renowned specialists in their fields and present the results of ongoing research, some of it obtained only very recently and not yet published in monograph form.
Free topological vector spaces
Gabriyelyan, Saak S.; Morris, Sidney A.
2016-01-01
We define and study the free topological vector space $\\mathbb{V}(X)$ over a Tychonoff space $X$. We prove that $\\mathbb{V}(X)$ is a $k_\\omega$-space if and only if $X$ is a $k_\\omega$-space. If $X$ is infinite, then $\\mathbb{V}(X)$ contains a closed vector subspace which is topologically isomorphic to $\\mathbb{V}(\\mathbb{N})$. It is proved that if $X$ is a $k$-space, then $\\mathbb{V}(X)$ is locally convex if and only if $X$ is discrete and countable. If $X$ is a metrizable space it is shown ...
The topological B model as a twisted spinning particle
International Nuclear Information System (INIS)
Marcus, Neil; Yankielowicz, Shimon
1994-01-01
The B-twisted topological sigma model coupled to topological gravity is supposed to be described by an ordinary field theory: a type of holomorphic Chern-Simons theory for the open string, and the Kodaira-Spencer theory for the closed string. We show that the B model can be represented as a particle theory, obtained by reducing the sigma model to one dimension, and replacing the coupling to topological gravity by a coupling to a twisted one-dimensional supergravity. The particle can be defined on any Kaehler manifold - it does not require the Calabi-Yau condition - so it may provide a more generalized setting for the B model than the topological sigma model.The one-loop partition function of the particle can be written in terms of the Ray-Singer torsion of the manifold, and agrees with that of the original B model. After showing how to deform the Kaehler and complex structures in the particle, we prove the independence of this partition function on the Kaehler structure, and investigate the origin of the holomorphic anomaly. To define other amplitudes, one needs to introduce interactions into the particle. The particle will then define a field theory, which may or may not be the Chern-Simons or Kodaira-Spencer theories. ((orig.))
Algebraic quantum gravity (AQG): I. Conceptual setup
International Nuclear Information System (INIS)
Giesel, K; Thiemann, T
2007-01-01
We introduce a new top down approach to canonical quantum gravity, called algebraic quantum gravity (AQG). The quantum kinematics of AQG is determined by an abstract *-algebra generated by a countable set of elementary operators labelled by an algebraic graph. The quantum dynamics of AQG is governed by a single master constraint operator. While AQG is inspired by loop quantum gravity (LQG), it differs drastically from it because in AQG there is fundamentally no topology or differential structure. A natural Hilbert space representation acquires the structure of an infinite tensor product (ITP) whose separable strong equivalence class Hilbert subspaces (sectors) are left invariant by the quantum dynamics. The missing information about the topology and differential structure of the spacetime manifold as well as about the background metric to be approximated is supplied by coherent states. Given such data, the corresponding coherent state defines a sector in the ITP which can be identified with a usual QFT on the given manifold and background. Thus, AQG contains QFT on all curved spacetimes at once, possibly has something to say about topology change and provides the contact with the familiar low energy physics. In particular, in two companion papers we develop semiclassical perturbation theory for AQG and LQG and thereby show that the theory admits a semiclassical limit whose infinitesimal gauge symmetry agrees with that of general relativity. In AQG everything is computable with sufficient precision and no UV divergences arise due to the background independence of the fundamental combinatorial structure. Hence, in contrast to lattice gauge theory on a background metric, no continuum limit has to be taken. There simply is no lattice regulator that must be sent to zero
International Nuclear Information System (INIS)
Dvali, Gia; Kolanovic, Marko; Nitti, Francesco; Gabadadze, Gregory
2002-01-01
We propose a framework in which the quantum gravity scale can be as low as 10 -3 eV. The key assumption is that the standard model ultraviolet cutoff is much higher than the quantum gravity scale. This ensures that we observe conventional weak gravity. We construct an explicit brane-world model in which the brane-localized standard model is coupled to strong 5D gravity of infinite-volume flat extra space. Because of the high ultraviolet scale, the standard model fields generate a large graviton kinetic term on the brane. This kinetic term 'shields' the standard model from the strong bulk gravity. As a result, an observer on the brane sees weak 4D gravity up to astronomically large distances beyond which gravity becomes five dimensional. Modeling quantum gravity above its scale by the closed string spectrum we show that the shielding phenomenon protects the standard model from an apparent phenomenological catastrophe due to the exponentially large number of light string states. The collider experiments, astrophysics, cosmology and gravity measurements independently point to the same lower bound on the quantum gravity scale, 10 -3 eV. For this value the model has experimental signatures both for colliders and for submillimeter gravity measurements. Black holes reveal certain interesting properties in this framework
Photoinduced Topological Phase Transitions in Topological Magnon Insulators.
Owerre, S A
2018-03-13
Topological magnon insulators are the bosonic analogs of electronic topological insulators. They are manifested in magnetic materials with topologically nontrivial magnon bands as realized experimentally in a quasi-two-dimensional (quasi-2D) kagomé ferromagnet Cu(1-3, bdc), and they also possess protected magnon edge modes. These topological magnetic materials can transport heat as well as spin currents, hence they can be useful for spintronic applications. Moreover, as magnons are charge-neutral spin-1 bosonic quasiparticles with a magnetic dipole moment, topological magnon materials can also interact with electromagnetic fields through the Aharonov-Casher effect. In this report, we study photoinduced topological phase transitions in intrinsic topological magnon insulators in the kagomé ferromagnets. Using magnonic Floquet-Bloch theory, we show that by varying the light intensity, periodically driven intrinsic topological magnetic materials can be manipulated into different topological phases with different sign of the Berry curvatures and the thermal Hall conductivity. We further show that, under certain conditions, periodically driven gapped topological magnon insulators can also be tuned to synthetic gapless topological magnon semimetals with Dirac-Weyl magnon cones. We envision that this work will pave the way for interesting new potential practical applications in topological magnetic materials.
Gravity localization on hybrid branes
Directory of Open Access Journals (Sweden)
D.F.S. Veras
2016-03-01
Full Text Available This work deals with gravity localization on codimension-1 brane worlds engendered by compacton-like kinks, the so-called hybrid branes. In such scenarios, the thin brane behavior is manifested when the extra dimension is outside the compact domain, where the energy density is non-trivial, instead of asymptotically as in the usual thick brane models. The zero mode is trapped in the brane, as required. The massive modes, although not localized in the brane, have important phenomenological implications such as corrections to the Newton's law. We study such corrections in the usual thick domain wall and in the hybrid brane scenarios. By means of suitable numerical methods, we attain the mass spectrum for the graviton and the corresponding wavefunctions. The spectra possess the usual linearly increasing behavior from the Kaluza–Klein theories. Further, we show that the 4D gravitational force is slightly increased at short distances. The first eigenstate contributes highly for the correction to the Newton's law. The subsequent normalized solutions have diminishing contributions. Moreover, we find out that the phenomenology of the hybrid brane is not different from the usual thick domain wall. The use of numerical techniques for solving the equations of the massive modes is useful for matching possible phenomenological measurements in the gravitational law as a probe to warped extra dimensions.
Introduction to massive neutrinos
International Nuclear Information System (INIS)
Kayser, B.
1984-01-01
We discuss the theoretical ideas which make it natural to expect that neutrinos do indeed have mass. Then we focus on the physical consequences of neutrino mass, including neutrino oscillation and other phenomena whose observation would be very interesting, and would serve to demonstrate that neutrinos are indeed massive. We comment on the legitimacy of comparing results from different types of experiments. Finally, we consider the question of whether neutrinos are their own antiparticles. We explain what this question means, discuss the nature of a neutrino which is its own antiparticles, and consider how one might determine experimentally whether neutrinos are their own antiparticles or not
Loop quantum gravity in asymptotically flat spaces
International Nuclear Information System (INIS)
Arnsdorf, M.
2000-01-01
This thesis describes applications and extensions of the loop variable approach to non-perturbative quantum gravity. The common theme of the work presented, is the need to generalise loop quantum gravity to be applicable in cases where space is asymptotically flat, and no longer compact as is usually assumed. This is important for the study of isolated gravitational systems. It also presents a natural context in which to search for the semi-classical limit, one of the main outstanding problems in loop quantum gravity. In the first part of the thesis we study how isolated gravitational systems can be attributed particle-like properties. In particular, we show how spinorial states can arise in pure loop quantum gravity if spatial topology is non-trivial, thus confirming an old conjecture of Friedman and Sorkin. Heuristically, this corresponds to the idea that we can rotate isolated regions of spatial topology relative to the environment at infinity, and that only a 4π-rotation will take us back to the original configuration. To do this we extend the standard loop quantum gravity formalism by introducing a compactification of our non-compact spatial manifold, and study the knotting of embedded graphs. The second part of the thesis takes a more systematic approach to the study of loop quantum gravity on non-compact spaces. We look for new representations of the loop algebra, which give rise to quantum theories that are inequivalent to the standard one. These theories naturally describe excitations of a fiducial background state, which is specified via the choice of its vacuum expectation values. In particular, we can choose background states that describe the geometries of non-compact manifolds. We also discuss how suitable background states can be constructed that can approximate classical phase space data, in our case holonomies along embedded paths and geometrical quantities related to areas and volumes. These states extend the notion of the weave and provide a
Topological field theories and duality
International Nuclear Information System (INIS)
Stephany, J.; Universidad Simon Bolivar, Caracas
1996-05-01
Topologically non trivial effects appearing in the discussion of duality transformations in higher genus manifold are discussed in a simple example, and their relation with the properties of Topological Field Theories is established. (author). 16 refs
Wireless sensor network topology control
Zuk, Olexandr; Romanjuk, Valeriy; Sova, Oleg
2010-01-01
Topology control process for the wireless sensor network is considered. In this article the use of rule base for making decision on the search of optimum network topology is offered for the realization of different aims of network management.
Topology optimization of viscoelastic rectifiers
DEFF Research Database (Denmark)
Jensen, Kristian Ejlebjærg; Szabo, Peter; Okkels, Fridolin
2012-01-01
An approach for the design of microfluidic viscoelastic rectifiers is presented based on a combination of a viscoelastic model and the method of topology optimization. This presumption free approach yields a material layout topologically different from experimentally realized rectifiers...
Towards topological quantum computer
Melnikov, D.; Mironov, A.; Mironov, S.; Morozov, A.; Morozov, An.
2018-01-01
Quantum R-matrices, the entangling deformations of non-entangling (classical) permutations, provide a distinguished basis in the space of unitary evolutions and, consequently, a natural choice for a minimal set of basic operations (universal gates) for quantum computation. Yet they play a special role in group theory, integrable systems and modern theory of non-perturbative calculations in quantum field and string theory. Despite recent developments in those fields the idea of topological quantum computing and use of R-matrices, in particular, practically reduce to reinterpretation of standard sets of quantum gates, and subsequently algorithms, in terms of available topological ones. In this paper we summarize a modern view on quantum R-matrix calculus and propose to look at the R-matrices acting in the space of irreducible representations, which are unitary for the real-valued couplings in Chern-Simons theory, as the fundamental set of universal gates for topological quantum computer. Such an approach calls for a more thorough investigation of the relation between topological invariants of knots and quantum algorithms.
Slope constrained Topology Optimization
DEFF Research Database (Denmark)
Petersson, J.; Sigmund, Ole
1998-01-01
The problem of minimum compliance topology optimization of an elastic continuum is considered. A general continuous density-energy relation is assumed, including variable thickness sheet models and artificial power laws. To ensure existence of solutions, the design set is restricted by enforcing...
Architecture, Drawing, Topology
DEFF Research Database (Denmark)
Meldgaard, Morten
This book presents contributions of drawing and text along with their many relationalities from ontology to history and vice versa in a range of reflections on architecture, drawing and topology. We hope to thereby indicate the potential of the theme in understanding not only the architecture of ...
LHCb Topological Trigger Reoptimization
INSPIRE-00400931; Ilten, Philip; Khairullin, Egor; Rogozhnikov, Alex; Ustyuzhanin, Andrey; Williams, Michael
2015-12-23
The main b-physics trigger algorithm used by the LHCb experiment is the so-called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger, which utilized a custom boosted decision tree algorithm, selected a nearly 100% pure sample of b-hadrons with a typical efficiency of 60-70%; its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and neural networks. The topological trigger algorithm is designed to select all "interesting" decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. ...
International Nuclear Information System (INIS)
Marmo, G.; Morandi, G.
1995-01-01
In this lecture some mathematical problems that arise when one deals with low-dimensional field theories, such as homotopy and topological invariants, differential calculus on Lie groups and coset spaces, fiber spaces and parallel transport, differential calculus on fiber bundles, sequences on principal bundles and Chern-Simons terms are discussed
Rendering the Topological Spines
Energy Technology Data Exchange (ETDEWEB)
Nieves-Rivera, D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-05-05
Many tools to analyze and represent high dimensional data already exits yet most of them are not flexible, informative and intuitive enough to help the scientists make the corresponding analysis and predictions, understand the structure and complexity of scientific data, get a complete picture of it and explore a greater number of hypotheses. With this in mind, N-Dimensional Data Analysis and Visualization (ND²AV) is being developed to serve as an interactive visual analysis platform with the purpose of coupling together a number of these existing tools that range from statistics, machine learning, and data mining, with new techniques, in particular with new visualization approaches. My task is to create the rendering and implementation of a new concept called topological spines in order to extend ND²AV's scope. Other existing visualization tools create a representation preserving either the topological properties or the structural (geometric) ones because it is challenging to preserve them both simultaneously. Overcoming such challenge by creating a balance in between them, the topological spines are introduced as a new approach that aims to preserve them both. Its render using OpenGL and C++ and is currently being tested to further on be implemented on ND²AV. In this paper I will present what are the Topological Spines and how they are rendered.
Coherence Multiplex System Topologies
Meijerink, Arjan; Taniman, R.O.; Heideman, G.H.L.M.; van Etten, Wim
2007-01-01
Coherence multiplexing is a potentially inexpensive form of optical code-division multiple access, which is particularly suitable for short-range applications with moderate bandwidth requirements, such as access networks, LANs, or interconnects. Various topologies are known for constructing an
Topological Trigger Developments
Likhomanenko, Tatiana
2015-01-01
The main b-physics trigger algorithm used by the LHCb experiment is the so-called topological trigger. The topological trigger selects vertices which are a) detached from the primary proton-proton collision and b) compatible with coming from the decay of a b-hadron. In the LHC Run 1, this trigger utilized a custom boosted decision tree algorithm, selected an almost 100% pure sample of b-hadrons with a typical efficiency of 60-70%, and its output was used in about 60% of LHCb papers. This talk presents studies carried out to optimize the topological trigger for LHC Run 2. In particular, we have carried out a detailed comparison of various machine learning classifier algorithms, e.g., AdaBoost, MatrixNet and uBoost. The topological trigger algorithm is designed to select all "interesting" decays of b-hadrons, but cannot be trained on every such decay. Studies have therefore been performed to determine how to optimize the performance of the classification algorithm on decays not used in the training. These inclu...
Towards topological quantum computer
Directory of Open Access Journals (Sweden)
D. Melnikov
2018-01-01
Full Text Available Quantum R-matrices, the entangling deformations of non-entangling (classical permutations, provide a distinguished basis in the space of unitary evolutions and, consequently, a natural choice for a minimal set of basic operations (universal gates for quantum computation. Yet they play a special role in group theory, integrable systems and modern theory of non-perturbative calculations in quantum field and string theory. Despite recent developments in those fields the idea of topological quantum computing and use of R-matrices, in particular, practically reduce to reinterpretation of standard sets of quantum gates, and subsequently algorithms, in terms of available topological ones. In this paper we summarize a modern view on quantum R-matrix calculus and propose to look at the R-matrices acting in the space of irreducible representations, which are unitary for the real-valued couplings in Chern–Simons theory, as the fundamental set of universal gates for topological quantum computer. Such an approach calls for a more thorough investigation of the relation between topological invariants of knots and quantum algorithms.
Adjoint entropy vs topological entropy
Giordano Bruno, Anna
2012-01-01
Recently the adjoint algebraic entropy of endomorphisms of abelian groups was introduced and studied. We generalize the notion of adjoint entropy to continuous endomorphisms of topological abelian groups. Indeed, the adjoint algebraic entropy is defined using the family of all finite-index subgroups, while we take only the subfamily of all open finite-index subgroups to define the topological adjoint entropy. This allows us to compare the (topological) adjoint entropy with the known topologic...
International Nuclear Information System (INIS)
Soltz, R; Vranas, P; Blumrich, M; Chen, D; Gara, A; Giampap, M; Heidelberger, P; Salapura, V; Sexton, J; Bhanot, G
2007-01-01
The theory of the strong nuclear force, Quantum Chromodynamics (QCD), can be numerically simulated from first principles on massively-parallel supercomputers using the method of Lattice Gauge Theory. We describe the special programming requirements of lattice QCD (LQCD) as well as the optimal supercomputer hardware architectures that it suggests. We demonstrate these methods on the BlueGene massively-parallel supercomputer and argue that LQCD and the BlueGene architecture are a natural match. This can be traced to the simple fact that LQCD is a regular lattice discretization of space into lattice sites while the BlueGene supercomputer is a discretization of space into compute nodes, and that both are constrained by requirements of locality. This simple relation is both technologically important and theoretically intriguing. The main result of this paper is the speedup of LQCD using up to 131,072 CPUs on the largest BlueGene/L supercomputer. The speedup is perfect with sustained performance of about 20% of peak. This corresponds to a maximum of 70.5 sustained TFlop/s. At these speeds LQCD and BlueGene are poised to produce the next generation of strong interaction physics theoretical results
Einstein gravity emerging from quantum weyl gravity
International Nuclear Information System (INIS)
Zee, A.
1983-01-01
We advocate a conformal invariant world described by the sum of the Weyl, Dirac, and Yang-Mills action. Quantum fluctuations bring back Einstein gravity so that the long-distance phenomenology is as observed. Formulas for the induced Newton's constant and Eddington's constant are derived in quantized Weyl gravity. We show that the analogue of the trace anomaly for the Weyl action is structurally similar to that for the Yang-Mills action
Topology of Document Retrieval Systems.
Everett, Daniel M.; Cater, Steven C.
1992-01-01
Explains the use of a topological structure to examine the closeness between documents in retrieval systems and analyzes the topological structure of a vector-space model, a fuzzy-set model, an extended Boolean model, a probabilistic model, and a TIRS (Topological Information Retrieval System) model. Proofs for the results are appended. (17…
Comparing topological charge definitions using topology fixing actions
International Nuclear Information System (INIS)
Bruckmann, Falk; Gruber, Florian; Jansen, Karl; Marinkovic, Marina; Urbach, Carsten; Wagner, Marc
2009-05-01
We investigate both the hyperbolic action and the determinant ratio action designed to fix the topological charge on the lattice. We show to what extent topology is fixed depending on the parameters of these actions, keeping the physical situation fixed. At the same time the agreement between different definitions of topological charge - the field theoretic and the index definition - is directly correlated to the degree topology is fixed. Moreover, it turns out that the two definitions agree very well. We also study finite volume effects arising in the static potential and related quantities due to topology fixing. (orig.)
Topological twist in four dimensions, R-duality and hyperinstantons
International Nuclear Information System (INIS)
Anselmi, D.; Fre, P.
1993-01-01
In this paper we continue the programme of topologically twisting N=2 theories in D=4, focusing on the coupling of vector multiplets to N=2 supergravity. We show that in the minimal case, namely when the special gometry prepotential F(X) is a quadratic polynomial, the theory has a so far unknown on-shell U(1) symmetry, that we name R-duality. R-duality is a generalization of the chiral-dual on-shell symmetry of N=2 pure supergravity and of the R-symmetry of N=2 super Yang-Mills theory. Thanks to this, the theory can be topologically twisted and topologically shifted, precisely as pure N=2 supergravity, to yield a natural coupling of topological gravity to topological Yang-Mills theory. The gauge-fixing condition that emerges from the twisting is the self-duality condition on the gauge field strength and on the spin connection. Hence our theory reduces to intersection theory in the moduli-space of gauge instantons living in gravitational instanton backgrounds. We remark that, for deep properties of the parent N=2 theory, the topological Yang-Mills theory we obtain by taking the flat space limit of our gravity-coupled lagrangian is different from the Donaldson theory constructed by Witten. Whether this difference is substantial and what its geometrical implications may be is yet to be seen. We also discuss the topological twist of the hypermultiplets leading to topological quaternionic sigma-models. The instantons of these models, named by us hyperinstantons, correspond to a notion of triholomorphic mappings discussed in the paper. In all cases the new ghost number is the sum of the old ghost number plus the R-duality charge. The observables described by the theory are briefly discussed. In conclusion, the topological twist of the complete N=2 theory defines intersection theory in the moduli-space of gauge instantons plus gravitational instantons plus hyperinstantons. This is possibly a new subject for further mathematical investigation. (orig.)
Testing the Larson relations in massive clumps
Traficante, A.; Duarte-Cabral, A.; Elia, D.; Fuller, G. A.; Merello, M.; Molinari, S.; Peretto, N.; Schisano, E.; Di Giorgio, A.
2018-06-01
We tested the validity of the three Larson relations in a sample of 213 massive clumps selected from the Herschel infrared Galactic Plane (Hi-GAL) survey, also using data from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey of 3-mm emission lines. The clumps are divided into five evolutionary stages so that we can also discuss the Larson relations as a function of evolution. We show that this ensemble does not follow the three Larson relations, regardless of the clump's evolutionary phase. A consequence of this breakdown is that the dependence of the virial parameter αvir on mass (and radius) is only a function of the gravitational energy, independent of the kinetic energy of the system; thus, αvir is not a good descriptor of clump dynamics. Our results suggest that clumps with clear signatures of infall motions are statistically indistinguishable from clumps with no such signatures. The observed non-thermal motions are not necessarily ascribed to turbulence acting to sustain the gravity, but they might be a result of the gravitational collapse at the clump scales. This seems to be particularly true for the most massive (M ≥ 1000 M⊙) clumps in the sample, where exceptionally high magnetic fields might not be enough to stabilize the collapse.
Fine topology and locally Minkowskian manifolds
Agrawal, Gunjan; Sinha, Soami Pyari
2018-05-01
Fine topology is one of the several well-known topologies of physical and mathematical relevance. In the present paper, it is obtained that the nonempty open sets of different dimensional Minkowski spaces with the fine topology are not homeomorphic. This leads to the introduction of a new class of manifolds. It turns out that the technique developed here is also applicable to some other topologies, namely, the s-topology, space topology, f-topology, and A-topology.
Thermodynamic and classical instability of AdS black holes in fourth-order gravity
International Nuclear Information System (INIS)
Myung, Yun Soo; Moon, Taeyoon
2014-01-01
We study thermodynamic and classical instability of AdS black holes in fourth-order gravity. These include the BTZ black hole in new massive gravity, Schwarzschild-AdS black hole, and higher-dimensional AdS black holes in fourth-order gravity. All thermodynamic quantities which are computed using the Abbot-Deser-Tekin method are used to study thermodynamic instability of AdS black holes. On the other hand, we investigate the s-mode Gregory-Laflamme instability of the massive graviton propagating around the AdS black holes. We establish the connection between the thermodynamic instability and the GL instability of AdS black holes in fourth-order gravity. This shows that the Gubser-Mitra conjecture holds for AdS black holes found from fourth-order gravity
Asymptotic symmetries, holography and topological hair
Mishra, Rashmish K.; Sundrum, Raman
2018-01-01
Asymptotic symmetries of AdS4 quantum gravity and gauge theory are derived by coupling the holographically dual CFT3 to Chern-Simons gauge theory and 3D gravity in a "probe" (large-level) limit. Despite the fact that the three-dimensional AdS4 boundary as a whole is consistent with only finite-dimensional asymptotic symmetries, given by AdS isometries, infinite-dimensional symmetries are shown to arise in circumstances where one is restricted to boundary subspaces with effectively two-dimensional geometry. A canonical example of such a restriction occurs within the 4D subregion described by a Wheeler-DeWitt wavefunctional of AdS4 quantum gravity. An AdS4 analog of Minkowski "super-rotation" asymptotic symmetry is probed by 3D Einstein gravity, yielding CFT2 structure (in a large central charge limit), via AdS3 foliation of AdS4 and the AdS3/CFT2 correspondence. The maximal asymptotic symmetry is however probed by 3D conformal gravity. Both 3D gravities have Chern-Simons formulation, manifesting their topological character. Chern-Simons structure is also shown to be emergent in the Poincare patch of AdS4, as soft/boundary limits of 4D gauge theory, rather than "put in by hand" as an external probe. This results in a finite effective Chern-Simons level. Several of the considerations of asymptotic symmetry structure are found to be simpler for AdS4 than for Mink4, such as non-zero 4D particle masses, 4D non-perturbative "hard" effects, and consistency with unitarity. The last of these in particular is greatly simplified because in some set-ups the time dimension is explicitly shared by each level of description: Lorentzian AdS4, CFT3 and CFT2. Relatedly, the CFT2 structure clarifies the sense in which the infinite asymptotic charges constitute a useful form of "hair" for black holes and other complex 4D states. An AdS4 analog of Minkowski "memory" effects is derived, but with late-time memory of earlier events being replaced by (holographic) "shadow" effects. Lessons
Topology optimized permanent magnet systems
Bjørk, R.; Bahl, C. R. H.; Insinga, A. R.
2017-09-01
Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a Λcool figure of merit of 0.472 is reached, which is an increase of 100% compared to a previous optimized design.
Undergraduate topology a working textbook
McCluskey, Aisling
2014-01-01
This textbook offers an accessible, modern introduction at undergraduate level to an area known variously as general topology, point-set topology or analytic topology with a particular focus on helping students to build theory for themselves. It is the result of several years of the authors' combined university teaching experience stimulated by sustained interest in advanced mathematical thinking and learning, alongside established research careers in analytic topology. Point-set topology is a discipline that needs relatively little background knowledge, but sufficient determination to grasp i
Topology optimized permanent magnet systems
DEFF Research Database (Denmark)
Bjørk, Rasmus; Bahl, Christian; Insinga, Andrea Roberto
2017-01-01
Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron...... and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a ΛcoolΛcool figure of merit of 0...
Nobel Lecture: Topological quantum matter*
Haldane, F. Duncan M.
2017-10-01
Nobel Lecture, presented December 8, 2016, Aula Magna, Stockholm University. I will describe the history and background of three discoveries cited in this Nobel Prize: The "TKNN" topological formula for the integer quantum Hall effect found by David Thouless and collaborators, the Chern insulator or quantum anomalous Hall effect, and its role in the later discovery of time-reversal-invariant topological insulators, and the unexpected topological spin-liquid state of the spin-1 quantum antiferromagnetic chain, which provided an initial example of topological quantum matter. I will summarize how these early beginnings have led to the exciting, and currently extremely active, field of "topological matter."
Graph topologies on closed multifunctions
Directory of Open Access Journals (Sweden)
Giuseppe Di Maio
2003-10-01
Full Text Available In this paper we study function space topologies on closed multifunctions, i.e. closed relations on X x Y using various hypertopologies. The hypertopologies are in essence, graph topologies i.e topologies on functions considered as graphs which are subsets of X x Y . We also study several topologies, including one that is derived from the Attouch-Wets filter on the range. We state embedding theorems which enable us to generalize and prove some recent results in the literature with the use of known results in the hyperspace of the range space and in the function space topologies of ordinary functions.
Ultrafilters and topologies on groups
Zelenyuk, Yevhen
2011-01-01
This book presents the relationship between ultrafilters and topologies on groups. It shows how ultrafilters are used in constructing topologies on groups with extremal properties and how topologies on groups serve in deriving algebraic results aboutultrafilters. Topics covered include: topological and left topological groups, ultrafilter semigroups, local homomorphisms and automorphisms, subgroups and ideal structure of ßG, almost maximal spaces and projectives of finite semigroups, resolvability of groups. This is a self-contained book aimed at graduate students and researchers working in to
International Nuclear Information System (INIS)
Brown, J.D.
1988-01-01
This book addresses the subject of gravity theories in two and three spacetime dimensions. The prevailing philosophy is that lower dimensional models of gravity provide a useful arena for developing new ideas and insights, which are applicable to four dimensional gravity. The first chapter consists of a comprehensive introduction to both two and three dimensional gravity, including a discussion of their basic structures. In the second chapter, the asymptotic structure of three dimensional Einstein gravity with a negative cosmological constant is analyzed. The third chapter contains a treatment of the effects of matter sources in classical two dimensional gravity. The fourth chapter gives a complete analysis of particle pair creation by electric and gravitational fields in two dimensions, and the resulting effect on the cosmological constant
Gravity interpretation via EULDPH
International Nuclear Information System (INIS)
Ebrahimzadeh Ardestani, V.
2003-01-01
Euler's homogeneity equation for determining the coordinates of the source body especially to estimate the depth (EULDPH) is discussed at this paper. This method is applied to synthetic and high-resolution real data such as gradiometric or microgravity data. Low-quality gravity data especially in the areas with a complex geology structure has rarely been used. The Bouguer gravity anomalies are computed from absolute gravity data after the required corrections. Bouguer anomaly is transferred to residual gravity anomaly. The gravity gradients are estimated from residual anomaly values. Bouguer anomaly is the gravity gradients, using EULDPH. The coordinates of the perturbing body will be determined. Two field examples one in the east of Tehran (Mard Abad) where we would like to determine the location of the anomaly (hydrocarbon) and another in the south-east of Iran close to the border with Afghanistan (Nosrat Abad) where we are exploring chromite are presented
Massively parallel multicanonical simulations
Gross, Jonathan; Zierenberg, Johannes; Weigel, Martin; Janke, Wolfhard
2018-03-01
Generalized-ensemble Monte Carlo simulations such as the multicanonical method and similar techniques are among the most efficient approaches for simulations of systems undergoing discontinuous phase transitions or with rugged free-energy landscapes. As Markov chain methods, they are inherently serial computationally. It was demonstrated recently, however, that a combination of independent simulations that communicate weight updates at variable intervals allows for the efficient utilization of parallel computational resources for multicanonical simulations. Implementing this approach for the many-thread architecture provided by current generations of graphics processing units (GPUs), we show how it can be efficiently employed with of the order of 104 parallel walkers and beyond, thus constituting a versatile tool for Monte Carlo simulations in the era of massively parallel computing. We provide the fully documented source code for the approach applied to the paradigmatic example of the two-dimensional Ising model as starting point and reference for practitioners in the field.
Massive Galileon positivity bounds
de Rham, Claudia; Melville, Scott; Tolley, Andrew J.; Zhou, Shuang-Yong
2017-09-01
The EFT coefficients in any gapped, scalar, Lorentz invariant field theory must satisfy positivity requirements if there is to exist a local, analytic Wilsonian UV completion. We apply these bounds to the tree level scattering amplitudes for a massive Galileon. The addition of a mass term, which does not spoil the non-renormalization theorem of the Galileon and preserves the Galileon symmetry at loop level, is necessary to satisfy the lowest order positivity bound. We further show that a careful choice of successively higher derivative corrections are necessary to satisfy the higher order positivity bounds. There is then no obstruction to a local UV completion from considerations of tree level 2-to-2 scattering alone. To demonstrate this we give an explicit example of such a UV completion.
Massively parallel mathematical sieves
Energy Technology Data Exchange (ETDEWEB)
Montry, G.R.
1989-01-01
The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We investigate two highly parallel sieves using scattered decomposition and compare their performance on a hypercube multiprocessor. A comparison of different parallelization techniques for the sieve illustrates the trade-offs necessary in the design and implementation of massively parallel algorithms for large ensemble computers.
Light-like scattering in quantum gravity
International Nuclear Information System (INIS)
Bjerrum-Bohr, N.E.J.; Donoghue, John F.; Holstein, Barry R.; Planté, Ludovic; Vanhove, Pierre
2016-01-01
We consider scattering in quantum gravity and derive long-range classical and quantum contributions to the scattering of light-like bosons and fermions (spin-0, spin-(1/2), spin-1) from an external massive scalar field, such as the Sun or a black hole. This is achieved by treating general relativity as an effective field theory and identifying the non-analytic pieces of the one-loop gravitational scattering amplitude. It is emphasized throughout the paper how modern amplitude techniques, involving spinor-helicity variables, unitarity, and squaring relations in gravity enable much simplified computations. We directly verify, as predicted by general relativity, that all classical effects in our computation are universal (in the context of matter type and statistics). Using an eikonal procedure we confirm the post-Newtonian general relativity correction for light-like bending around large stellar objects. We also comment on treating effects from quantum ℏ dependent terms using the same eikonal method.
Light-like scattering in quantum gravity
Energy Technology Data Exchange (ETDEWEB)
Bjerrum-Bohr, N.E.J. [Niels Bohr International Academy & Discovery Center, Niels Bohr Institute,University of Copenhagen, Blegdamsvej 17, Copenhagen Ø, DK-2100 (Denmark); Donoghue, John F. [Department of Physics-LGRT, University of Massachusetts,Amherst, MA, 01003 (United States); Holstein, Barry R. [Department of Physics-LGRT, University of Massachusetts,Amherst, MA, 01003 (United States); Kavli Institute for Theoretical Physics, University of California,Santa Barbara, CA, 93016 (United States); Planté, Ludovic; Vanhove, Pierre [CEA, DSM, Institut de Physique Théorique, IPhT, CNRS MPPU, URA2306,Saclay, Gif-sur-Yvette, F-91191 (France)
2016-11-21
We consider scattering in quantum gravity and derive long-range classical and quantum contributions to the scattering of light-like bosons and fermions (spin-0, spin-(1/2), spin-1) from an external massive scalar field, such as the Sun or a black hole. This is achieved by treating general relativity as an effective field theory and identifying the non-analytic pieces of the one-loop gravitational scattering amplitude. It is emphasized throughout the paper how modern amplitude techniques, involving spinor-helicity variables, unitarity, and squaring relations in gravity enable much simplified computations. We directly verify, as predicted by general relativity, that all classical effects in our computation are universal (in the context of matter type and statistics). Using an eikonal procedure we confirm the post-Newtonian general relativity correction for light-like bending around large stellar objects. We also comment on treating effects from quantum ℏ dependent terms using the same eikonal method.
International Nuclear Information System (INIS)
Mielke, Eckehard W.
2006-01-01
Anomalies in Yang-Mills type gauge theories of gravity are reviewed. Particular attention is paid to the relation between the Dirac spin, the axial current j5 and the non-covariant gauge spin C. Using diagrammatic techniques, we show that only generalizations of the U(1)- Pontrjagin four-form F and F = dC arise in the chiral anomaly, even when coupled to gravity. Implications for Ashtekar's canonical approach to quantum gravity are discussed
Floquet topological insulators for sound
Fleury, Romain; Khanikaev, Alexander B.; Alù, Andrea
2016-06-01
The unique conduction properties of condensed matter systems with topological order have recently inspired a quest for the similar effects in classical wave phenomena. Acoustic topological insulators, in particular, hold the promise to revolutionize our ability to control sound, allowing for large isolation in the bulk and broadband one-way transport along their edges, with topological immunity against structural defects and disorder. So far, these fascinating properties have been obtained relying on moving media, which may introduce noise and absorption losses, hindering the practical potential of topological acoustics. Here we overcome these limitations by modulating in time the acoustic properties of a lattice of resonators, introducing the concept of acoustic Floquet topological insulators. We show that acoustic waves provide a fertile ground to apply the anomalous physics of Floquet topological insulators, and demonstrate their relevance for a wide range of acoustic applications, including broadband acoustic isolation and topologically protected, nonreciprocal acoustic emitters.
Probing TeV gravity with the ATLAS detector
International Nuclear Information System (INIS)
Lendermann, Victor
2009-01-01
Models with compactified extra space dimensions offer a new way to address outstanding problems in and beyond the Standard Model. In these models, the strength of gravity is strongly increased at small distances, which opens up the possibility of observing quantum gravity effects in the TeV energy range reachable by the LHC. One of the most spectacular phenomena would be the production of microscopic black holes. Searches for black holes are foreseen in the ATLAS experiment with the start-up of data taking in 2009. We present feasibility studies for the triggering, selection and reconstruction of the black hole event topologies, the black hole discovery potential and their identification.