Action principle for the generalized harmonic formulation of general relativity
International Nuclear Information System (INIS)
Brown, J. David
2011-01-01
An action principle for the generalized harmonic formulation of general relativity is presented. The action is a functional of the spacetime metric and the gauge source vector. An action principle for the Z4 formulation of general relativity has been proposed recently by Bona, Bona-Casas, and Palenzuela. The relationship between the generalized harmonic action and the Bona, Bona-Casas, and Palenzuela action is discussed in detail.
Diffeomorphism invariance in the Hamiltonian formulation of General Relativity
International Nuclear Information System (INIS)
Kiriushcheva, N.; Kuzmin, S.V.; Racknor, C.; Valluri, S.R.
2008-01-01
It is shown that when the Einstein-Hilbert Lagrangian is considered without any non-covariant modifications or change of variables, its Hamiltonian formulation leads to results consistent with principles of General Relativity. The first-class constraints of such a Hamiltonian formulation, with the metric tensor taken as a canonical variable, allow one to derive the generator of gauge transformations, which directly leads to diffeomorphism invariance. The given Hamiltonian formulation preserves general covariance of the transformations derivable from it. This characteristic should be used as the crucial consistency requirement that must be met by any Hamiltonian formulation of General Relativity
Spinning fluids in general relativity: a variational formulation
International Nuclear Information System (INIS)
Oliveira, H.P. de; Salim, J.M.
1990-01-01
In this paper we present a variational formulation for spinning fluids in General Relativity. In our model each volume element of the fluid has rigid microstructure. We deduce a symmetrical energy-moment tensor where there is an explicit contribution of kinetic spin energy to the total energy. (author)
Numerical performance of the parabolized ADM formulation of general relativity
International Nuclear Information System (INIS)
Paschalidis, Vasileios; Hansen, Jakob; Khokhlov, Alexei
2008-01-01
In a recent paper [Vasileios Paschalidis, Phys. Rev. D 78, 024002 (2008).], the first coauthor presented a new parabolic extension (PADM) of the standard 3+1 Arnowitt, Deser, Misner (ADM) formulation of the equations of general relativity. By parabolizing first-order ADM in a certain way, the PADM formulation turns it into a well-posed system which resembles the structure of mixed hyperbolic-second-order parabolic partial differential equations. The surface of constraints of PADM becomes a local attractor for all solutions and all possible well-posed gauge conditions. This paper describes a numerical implementation of PADM and studies its accuracy and stability in a series of standard numerical tests. Numerical properties of PADM are compared with those of standard ADM and its hyperbolic Kidder, Scheel, Teukolsky (KST) extension. The PADM scheme is numerically stable, convergent, and second-order accurate. The new formulation has better control of the constraint-violating modes than ADM and KST.
Mixed hyperbolic-second-order-parabolic formulations of general relativity
International Nuclear Information System (INIS)
Paschalidis, Vasileios
2008-01-01
Two new formulations of general relativity are introduced. The first one is a parabolization of the Arnowitt-Deser-Misner formulation and is derived by the addition of combinations of the constraints and their derivatives to the right-hand side of the Arnowitt-Deser-Misner evolution equations. The desirable property of this modification is that it turns the surface of constraints into a local attractor because the constraint propagation equations become second-order parabolic independently of the gauge conditions employed. This system may be classified as mixed hyperbolic--second-order parabolic. The second formulation is a parabolization of the Kidder-Scheel-Teukolsky formulation and is a manifestly mixed strongly hyperbolic--second-order-parabolic set of equations, bearing thus resemblance to the compressible Navier-Stokes equations. As a first test, a stability analysis of flat space is carried out and it is shown that the first modification exponentially damps and smoothes all constraint-violating modes. These systems provide a new basis for constructing schemes for long-term and stable numerical integration of the Einstein field equations.
Gauge stability of 3+1 formulations of general relativity
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Khokhlov, A M; Novikov, I D
2002-01-01
We present a general approach to the analysis of gauge stability of 3+1 formulations of general relativity (GR). Evolution of coordinate perturbations and the corresponding perturbations of lapse and shift can be described by a system of eight quasi-linear partial differential equations. Stability with respect to gauge perturbations depends on the choice of gauge and a background metric, but it does not depend on a particular form of a 3+1 system if its constrained solutions are equivalent to those of the Einstein equations. Stability of a number of known gauges is investigated in the limit of short-wavelength perturbations. All fixed gauges except a synchronous gauge are found to be ill posed. A maximal slicing gauge and its parabolic extension are shown to be ill posed as well. A necessary condition is derived for well-posedness of metric-dependent algebraic gauges. Well-posed metric-dependent gauges are found, however, to be generally unstable. Both instability and ill-posedness are associated with the existence of growing modes of coordinate perturbations related to perturbations of physical accelerations of reference frames
On a covariant 2+2 formulation of the initial value problem in general relativity
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Smallwood, J.
1980-03-01
The initial value problems in general relativity are considered from a geometrical standpoint with especial reference to the development of a covariant 2+2 formalism in which space-time is foliated by space-like 2-surfaces under the headings; the Cauchy problem in general relativity, the covariant 3+1 formulation of the Cauchy problem, characteristic and mixed initial value problems, on locally imbedding a family of null hypersurfaces, the 2+2 formalism, the 2+2 formulation of the Cauchy problem, the 2+2 formulation of the characteristic and mixed initial value problems, and a covariant Lagrangian 2+2 formulation. (U.K.)
Numerical performance of the parabolized ADM (PADM) formulation of General Relativity
Paschalidis, Vasileios; Hansen, Jakob; Khokhlov, Alexei
2007-01-01
In a recent paper the first coauthor presented a new parabolic extension (PADM) of the standard 3+1 Arnowitt, Deser, Misner formulation of the equations of general relativity. By parabolizing first-order ADM in a certain way, the PADM formulation turns it into a mixed hyperbolic - second-order parabolic, well-posed system. The surface of constraints of PADM becomes a local attractor for all solutions and all possible well-posed gauge conditions. This paper describes a numerical implementation...
The geometry of the SLsub(2,c) gauge formulation of general relativity
International Nuclear Information System (INIS)
Kaye, M.
1978-01-01
The formulation of Einstein's general theory of relativity as an SLsub(2,c) gauge theory is considered. Use is made of the language of fibre bundles and general arguments are put forward in favour of the SLsub(2,c) approach to problems connected with the study of the space-time structure. The possibility of deriving the dynamics of the theory from a Yang-Mills-type Lagrangian density is discussed. Finally, the spinor approach is compared with other approaches to the problem of formulating Einstein's theory as a gauge theory
The Hamiltonian of Einstein affine-metric formulation of general relativity
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Kiriushcheva, N.; Kuzmin, S.V.
2010-01-01
It is shown that the Hamiltonian of the Einstein affine-metric (first-order) formulation of General Relativity (GR) leads to a constraint structure that allows the restoration of its unique gauge invariance, four-diffeomorphism, without the need of any field dependent redefinition of gauge parameters as in the case of the second-order formulation. In the second-order formulation of ADM gravity the need for such a redefinition is the result of the non-canonical change of variables (Xiv:0809.0097). For the first-order formulation, the necessity of such a redefinition ''to correspond to diffeomorphism invariance'' (reported by Ghalati, arXiv:0901.3344) is just an artifact of using the Henneaux-Teitelboim-Zanelli ansatz (Nucl. Phys. B 332:169, 1990), which is sensitive to the choice of linear combination of tertiary constraints. This ansatz cannot be used as an algorithm for finding a gauge invariance, which is a unique property of a physical system, and it should not be affected by different choices of linear combinations of non-primary first class constraints. The algorithm of Castellani (Ann. Phys. 143:357, 1982) is free from such a deficiency and it leads directly to four-diffeomorphism invariance for first, as well as for second-order Hamiltonian formulations of GR. The distinct role of primary first class constraints, the effect of considering different linear combinations of constraints, the canonical transformations of phase-space variables, and their interplay are discussed in some detail for Hamiltonians of the second- and first-order formulations of metric GR. The first-order formulation of Einstein-Cartan theory, which is the classical background of Loop Quantum Gravity, is also discussed. (orig.)
Pure connection formulation, twistors, and the chase for a twistor action for general relativity
Herfray, Yannick
2017-11-01
This paper establishes the relation between traditional results from the (Euclidean) twistor theory and chiral formulations of general relativity (GR), especially the pure connection formulation. Starting from an SU(2)-connection only, we show how to construct natural complex data on twistor space, mainly an almost Hermitian structure and a connection on some complex line bundle. Only when this almost Hermitian structure is integrable is the connection related to an anti-self-dual-Einstein metric and makes contact with the usual results. This leads to a new proof of the non-linear graviton theorem. Finally, we discuss what new strategies this "connection approach" to twistors suggests for constructing a twistor action for gravity. In Appendix A, we also review all known chiral Lagrangians for GR.
Ether formulations of relativity
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Duffy, M.C.
1980-01-01
Contemporary ether theories are surveyed and criticised, especially those formally identical to orthodox Relativity. The historical development of Relativity, Special and General, in terms of an ether, is briefly indicated. Classical interpretations of Generalized Relativity using ether are compared to Euclidean formulations using a background space. The history of a sub-group of theories, formulating a 'new' Relativity involving modified transforms, is outlined. According to the theory with which they agree, recent supposed detections of drift are classified and criticised. Cosmological evidence suggesting an ether is mentioned. Only ether theories formally identical to Relativity have been published in depth. They stand criticised as being contrary to the positivist spirit. The history of mechanical analogues is traced, from Hartley's representing gravitating matter as spherical standing waves, to recent suggestions that vortex-sponge might model electromagnetic, quantum, uncertainty and faster-than-light phenomena. Contemporary theories are particular physical theories, themselves 'second interpretations' of a primary mathematical model. Mechanical analogues are auxiliary, not necessary, to other theory, disclosing relationships between classical and non-classical descriptions of assemblies charging state. The ether-relativity polemic, part of a broader dispute about relativity, is founded on mistaken conceptions of the roles of mathematical and physical models, mechanical analogues; and a distored view of history, which indicates that ether theories have become relativistic. (author)
Expansion Formulation of General Relativity: the Gauge Functions for Energy-Momentum Tensor
Beloushko, Konstantin; Karbanovski, Valeri
At present the one of the GR (General Relativity) basic problem remains a definition of the gravitation field (GF) energy. We shall analyze this content. As well known, the energy-momentum ``tensor'' (EMT) of GF was introduced by Einstein [1] with purpose of the SRT (Special Relativity Theory) generalization. It supposed also, that EMT of matter satisfy to the condition begin{equation} ⪉bel{GrindEQ__1_1_} T^{ik} _{;i} =0 (a semicolon denotes a covariant differentiation with respect to coordinates). In absence of GF the equation (ref{GrindEQ__1_1_}) reduces to a corresponding SRT expression begin{equation} ⪉bel{GrindEQ__1_2_} T^{ik} _{,i} =0 (a comma denotes a differentiation with respect to coordinates of space-time). Obviously, the ``conservation law'' (ref{GrindEQ__1_2_}) is not broken by transformation begin{equation} ⪉bel{GrindEQ__1_3_} T^{ik} to tilde{T}^{ik} =T^{ik} +h^{ikl} _{,l} , where for h(ikl) takes place a constrain begin{equation} ⪉bel{GrindEQ__1_4_} h^{ikl} =-h^{ilk} Later the given property has been used for a construction ``pseudo-tensor'' tau (ik) of ``pure'' GF [2, S 96] begin{equation} ⪉bel{GrindEQ__1_5_} -gleft(frac{c^{4} }{8pi G} left(R^{ik} -frac{1}{2} g^{ik} Rright)+tau ^{ik} right)=h^{ikl} _{,l} However such definition was a consequence of non-covariant transition from a reference system with condition g(ik) _{,l} =0 to an arbitrary frame. Therefore the Landau-Lifshitz pseudo-tensor has no physical contents and considered problem remains actual. ``The non-covariant character'' of GF energy was the reason for criticism of GR as Einstein's contemporaries [3, 4], as and during the subsequent period (see, for example, [5]). In [6] were analyzed the grounds of given problem, which are connected with a formulation indefiniteness of ``the conservation law'' in curved space-time. In [7] contends, that the gravitational energy in EMT can be separated only ``artificially'' by a choice of the certain coordinate system. In [8] is concluded
Canonical formulation of general-relativistic theories
International Nuclear Information System (INIS)
Bergmann, P.G.
1987-01-01
With the birth of quantum field theory in the late twenties physicists decided that nature could not be half classical and half quantum, and that the gravitational field ought to be quanticized, just as the electromagnetic field had been. One could accept the group of differomorphisms as a fundamental characteristic of general relativity (and indeed of all general-relativistic theories), and proceed to construct a quantum field-theory that was adapted to that group. Quantization would be attempted by way of a Hamiltonian formulation of the (classical) theory, and quantum commutation relations be patterned after the Poisson brackets arising in that formulation. This program is usually called the canonical quantization program, whereas the weak-field approach is known as covariant quantization. The first steps, conceived entirely within the framework of the classical theory, turned out to be beset with technical and conceptual difficulties, which today are essentially resolved. In this paper the author traces out these initial steps
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Kenyon, I.R.
1990-01-01
General relativity is discussed in this book at a level appropriate to undergraduate students of physics and astronomy. It describes concepts and experimental results, and provides a succinct account of the formalism. A brief review of special relativity is followed by a discussion of the equivalence principle and its implications. Other topics covered include the concepts of curvature and the Schwarzschild metric, test of the general theory, black holes and their properties, gravitational radiation and methods for its detection, the impact of general relativity on cosmology, and the continuing search for a quantum theory of gravity. (author)
Straumann, Norbert
2013-01-01
This book provides a completely revised and expanded version of the previous classic edition ‘General Relativity and Relativistic Astrophysics’. In Part I the foundations of general relativity are thoroughly developed, while Part II is devoted to tests of general relativity and many of its applications. Binary pulsars – our best laboratories for general relativity – are studied in considerable detail. An introduction to gravitational lensing theory is included as well, so as to make the current literature on the subject accessible to readers. Considerable attention is devoted to the study of compact objects, especially to black holes. This includes a detailed derivation of the Kerr solution, Israel’s proof of his uniqueness theorem, and a derivation of the basic laws of black hole physics. Part II ends with Witten’s proof of the positive energy theorem, which is presented in detail, together with the required tools on spin structures and spinor analysis. In Part III, all of the differential geomet...
International Nuclear Information System (INIS)
Gourgoulhon, Eric
2013-01-01
The author proposes a course on general relativity. He first presents a geometrical framework by addressing, presenting and discussion the following notions: the relativistic space-time, the metric tensor, Universe lines, observers, principle of equivalence and geodesics. In the next part, he addresses gravitational fields with spherical symmetry: presentation of the Schwarzschild metrics, radial light geodesics, gravitational spectral shift (Einstein effect), orbitals of material objects, photon trajectories. The next parts address the Einstein equation, black holes, gravitational waves, and cosmological solutions. Appendices propose a discussion of the relationship between relativity and GPS, some problems and their solutions, and Sage codes
Generalized metric formulation of double field theory on group manifolds
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Blumenhagen, Ralph; Bosque, Pascal du; Hassler, Falk; Lüst, Dieter
2015-01-01
We rewrite the recently derived cubic action of Double Field Theory on group manifolds http://dx.doi.org/10.1007/JHEP02(2015)001 in terms of a generalized metric and extrapolate it to all orders in the fields. For the resulting action, we derive the field equations and state them in terms of a generalized curvature scalar and a generalized Ricci tensor. Compared to the generalized metric formulation of DFT derived from tori, all these quantities receive additional contributions related to the non-trivial background. It is shown that the action is invariant under its generalized diffeomorphisms and 2D-diffeomorphisms. Imposing additional constraints relating the background and fluctuations around it, the precise relation between the proposed generalized metric formulation of DFT WZW and of original DFT from tori is clarified. Furthermore, we show how to relate DFT WZW of the WZW background with the flux formulation of original DFT.
Generalized metric formulation of double field theory on group manifolds
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Blumenhagen, Ralph [Max-Planck-Institut für Physik,Föhringer Ring 6, 80805 München (Germany); Bosque, Pascal du [Arnold-Sommerfeld-Center für Theoretische Physik,Department für Physik, Ludwig-Maximilians-Universität München,Theresienstraße 37, 80333 München (Germany); Hassler, Falk [Max-Planck-Institut für Physik,Föhringer Ring 6, 80805 München (Germany); Lüst, Dieter [Max-Planck-Institut für Physik,Föhringer Ring 6, 80805 München (Germany); Arnold-Sommerfeld-Center für Theoretische Physik,Department für Physik, Ludwig-Maximilians-Universität München,Theresienstraße 37, 80333 München (Germany); CERN, PH-TH,1211 Geneva 23 (Switzerland)
2015-08-13
We rewrite the recently derived cubic action of Double Field Theory on group manifolds http://dx.doi.org/10.1007/JHEP02(2015)001 in terms of a generalized metric and extrapolate it to all orders in the fields. For the resulting action, we derive the field equations and state them in terms of a generalized curvature scalar and a generalized Ricci tensor. Compared to the generalized metric formulation of DFT derived from tori, all these quantities receive additional contributions related to the non-trivial background. It is shown that the action is invariant under its generalized diffeomorphisms and 2D-diffeomorphisms. Imposing additional constraints relating the background and fluctuations around it, the precise relation between the proposed generalized metric formulation of DFT{sub WZW} and of original DFT from tori is clarified. Furthermore, we show how to relate DFT{sub WZW} of the WZW background with the flux formulation of original DFT.
Probabilites in the general boundary formulation
Energy Technology Data Exchange (ETDEWEB)
Oeckl, Robert [Instituto de Matematicas, UNAM, Campus Morelia, C.P. 58190, Morelia, Michoacan (Mexico)
2007-05-15
We give an introductory account of the general boundary formulation of quantum theory. We refine its probability interpretation and emphasize a conceptual and historical perspective. We give motivations from quantum gravity and illustrate them with a scenario for describing gravitons in quantum gravity.
Modern approach to relativity theory (radar formulation)
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1991-01-01
The main peculiarities of the radar formulation of the relativity theory are presented. This formulation operates with the retarded (light) distances and relativistic or radar length introduced on their basis. 21 refs.; 1 tab
International Nuclear Information System (INIS)
Hayashi, K.; Shirafuji, T.
1979-01-01
A gravitational theory is formulated on the Weitzenboeck space-time, characterized by the vanishing curvature tensor (absolute parallelism) and by the torsion tensor formed of four parallel vector fields. This theory is called new general relativity, since Einstein in 1928 first gave its original form. New general relativity has three parameters c 1 , c 2 , and lambda, besides the Einstein constant kappa. In this paper we choose c 1 = 0 = c 2 , leaving open lambda. We prove, among other things, that (i) a static, spherically symmetric gravitational field is given by the Schwarzschild metric, that (ii) in the weak-field approximation an antisymmetric field of zero mass and zero spin exists, besides gravitons, and that (iii) new general relativity agrees with all the experiments so far carried out
Lagrangian formulation of the general relativistic Poynting-Robertson effect
De Falco, Vittorio; Battista, Emmanuele; Falanga, Maurizio
2018-04-01
We propose the Lagrangian formulation for describing the motion of a test particle in a general relativistic, stationary, and axially symmetric spacetime. The test particle is also affected by a radiation field, modeled as a coherent flux of photons traveling along the null geodesics of the background spacetime, including the general relativistic Poynting-Robertson effect. The innovative part of this work is to prove the existence of the potential linked to the dissipative action caused by the Poynting-Robertson effect in general relativity through the help of an integrating factor, depending on the energy of the system. Generally, such kinds of inverse problems involving dissipative effects might not admit a Lagrangian formulation; especially, in general relativity, there are no examples of such attempts in the literature so far. We reduce this general relativistic Lagrangian formulation to the classic case in the weak-field limit. This approach facilitates further studies in improving the treatment of the radiation field, and it contains, for example, some implications for a deeper comprehension of the gravitational waves.
International Nuclear Information System (INIS)
Khorrami, M.
1995-01-01
A general formulation for discrete-time quantum mechanics, based on Feynman's method in ordinary quantum mechanics, is presented. It is shown that the ambiguities present in ordinary quantum mechanics (due to noncommutativity of the operators), are no longer present here. Then the criteria for the unitarity of the evolution operator are examined. It is shown that the unitarity of the evolution operator puts restrictions on the form of the action, and also implies the existence of a solution for the classical initial-value problem. 13 refs
The gauge in general relativity
International Nuclear Information System (INIS)
Cohn, J.
1975-01-01
The view is taken that the field equations of General Relativity, without a definition of congruence of length and time intervals at different events, are without physical content. The possibility is explored that the customary Einstein field equations are to be used but with a different congruence definition than is customary. When these resulting equations are, in turn, expressed with the customary congruence, they comprise a new set of field equations physically not equivalent to either Einstein's or Brans-Dicke's formulations of general relativity. Similarities with Einstein's and Brans-Dicke's formulations are discussed, and the possibility of experimental confirmation of these new equations is also briefly considered. (author)
Generalized variational formulations for extended exponentially fractional integral
Directory of Open Access Journals (Sweden)
Zuo-Jun Wang
2016-01-01
Full Text Available Recently, the fractional variational principles as well as their applications yield a special attention. For a fractional variational problem based on different types of fractional integral and derivatives operators, corresponding fractional Lagrangian and Hamiltonian formulation and relevant Euler–Lagrange type equations are already presented by scholars. The formulations of fractional variational principles still can be developed more. We make an attempt to generalize the formulations for fractional variational principles. As a result we obtain generalized and complementary fractional variational formulations for extended exponentially fractional integral for example and corresponding Euler–Lagrange equations. Two illustrative examples are presented. It is observed that the formulations are in exact agreement with the Euler–Lagrange equations.
Modern canonical quantum general relativity
Thiemann, Thomas
2007-01-01
This is an introduction to the by now fifteen years old research field of canonical quantum general relativity, sometimes called "loop quantum gravity". The term "modern" in the title refers to the fact that the quantum theory is based on formulating classical general relativity as a theory of connections rather than metrics as compared to in original version due to Arnowitt, Deser and Misner. Canonical quantum general relativity is an attempt to define a mathematically rigorous, non-perturbative, background independent theory of Lorentzian quantum gravity in four spacetime dimensions in the continuum. The approach is minimal in that one simply analyzes the logical consequences of combining the principles of general relativity with the principles of quantum mechanics. The requirement to preserve background independence has lead to new, fascinating mathematical structures which one does not see in perturbative approaches, e.g. a fundamental discreteness of spacetime seems to be a prediction of the theory provi...
Ridgely, Charles T.
2010-01-01
Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced…
Multiphase layered oxide growth on pure metals. I. General formulation
International Nuclear Information System (INIS)
Fromhold, A.T. Jr.
1982-01-01
A general formulation for the simultaneous growth of any number of layered planar oxide phases on a pure metal under diffusion-controlled conditions has been developed. Four individual situations have been developed in detail, namely, situations in which the predominant mode of ion transport is by cation interstitials, cation vacancies, anion interstitials, or anion vacancies. The generalized formulation enables the determination of quasi-steady-state growth kinetics following step function changes in the experimental conditions such as ambient oxygen pressure or temperature. Numerical evaluation of the coupled growth equations for the individual phases is required to deduce the general predictions of the theory. In the limit of two-layer growth by cation interstitial diffusion, the present formulation reproduces the earlier results of Fromhold and Sato
Koopmans' theorem in the Hartree-Fock method. General formulation
Plakhutin, Boris N.
2018-03-01
This work presents a general formulation of Koopmans' theorem (KT) in the Hartree-Fock (HF) method which is applicable to molecular and atomic systems with arbitrary orbital occupancies and total electronic spin including orbitally degenerate (OD) systems. The new formulation is based on the full set of variational conditions imposed upon the HF orbitals by the variational principle for the total energy and the conditions imposed by KT on the orbitals of an ionized electronic shell [B. N. Plakhutin and E. R. Davidson, J. Chem. Phys. 140, 014102 (2014)]. Based on these conditions, a general form of the restricted open-shell HF method is developed, whose eigenvalues (orbital energies) obey KT for the whole energy spectrum. Particular attention is paid to the treatment of OD systems, for which the new method gives a number of unexpected results. For example, the present method gives four different orbital energies for the triply degenerate atomic level 2p in the second row atoms B to F. Based on both KT conditions and a parallel treatment of atoms B to F within a limited configuration interaction approach, we prove that these four orbital energies, each of which is triply degenerate, are related via KT to the energies of different spin-dependent ionization and electron attachment processes (2p)N → (2p ) N ±1. A discussion is also presented of specific limitations of the validity of KT in the HF method which arise in OD systems. The practical applicability of the theory is verified by comparing KT estimates of the ionization potentials I2s and I2p for the second row open-shell atoms Li to F with the relevant experimental data.
A general field-covariant formulation of quantum field theory
International Nuclear Information System (INIS)
Anselmi, Damiano
2013-01-01
In all nontrivial cases renormalization, as it is usually formulated, is not a change of integration variables in the functional integral, plus parameter redefinitions, but a set of replacements, of actions and/or field variables and parameters. Because of this, we cannot write simple identities relating bare and renormalized generating functionals, or generating functionals before and after nonlinear changes of field variables. In this paper we investigate this issue and work out a general field-covariant approach to quantum field theory, which allows us to treat all perturbative changes of field variables, including the relation between bare and renormalized fields, as true changes of variables in the functional integral, under which the functionals Z and W=lnZ behave as scalars. We investigate the relation between composite fields and changes of field variables, and we show that, if J are the sources coupled to the elementary fields, all changes of field variables can be expressed as J-dependent redefinitions of the sources L coupled to the composite fields. We also work out the relation between the renormalization of variable-changes and the renormalization of composite fields. Using our transformation rules it is possible to derive the renormalization of a theory in a new variable frame from the renormalization in the old variable frame, without having to calculate it anew. We define several approaches, useful for different purposes, in particular a linear approach where all variable changes are described as linear source redefinitions. We include a number of explicit examples. (orig.)
Theoretical general relativity: 1979
International Nuclear Information System (INIS)
Bergmann, O.
1979-01-01
The metric and field equations of Einstein's general relativity theory are written down. Solutions to the equations are discussed. Connection is made between relativity theory and elementary particle theory. Possibilities for a unified field theory are considered
Measurement Uncertainty Relations for Discrete Observables: Relative Entropy Formulation
Barchielli, Alberto; Gregoratti, Matteo; Toigo, Alessandro
2018-02-01
We introduce a new information-theoretic formulation of quantum measurement uncertainty relations, based on the notion of relative entropy between measurement probabilities. In the case of a finite-dimensional system and for any approximate joint measurement of two target discrete observables, we define the entropic divergence as the maximal total loss of information occurring in the approximation at hand. For fixed target observables, we study the joint measurements minimizing the entropic divergence, and we prove the general properties of its minimum value. Such a minimum is our uncertainty lower bound: the total information lost by replacing the target observables with their optimal approximations, evaluated at the worst possible state. The bound turns out to be also an entropic incompatibility degree, that is, a good information-theoretic measure of incompatibility: indeed, it vanishes if and only if the target observables are compatible, it is state-independent, and it enjoys all the invariance properties which are desirable for such a measure. In this context, we point out the difference between general approximate joint measurements and sequential approximate joint measurements; to do this, we introduce a separate index for the tradeoff between the error of the first measurement and the disturbance of the second one. By exploiting the symmetry properties of the target observables, exact values, lower bounds and optimal approximations are evaluated in two different concrete examples: (1) a couple of spin-1/2 components (not necessarily orthogonal); (2) two Fourier conjugate mutually unbiased bases in prime power dimension. Finally, the entropic incompatibility degree straightforwardly generalizes to the case of many observables, still maintaining all its relevant properties; we explicitly compute it for three orthogonal spin-1/2 components.
General time-dependent formulation of quantum scattering theory
International Nuclear Information System (INIS)
Althorpe, Stuart C.
2004-01-01
We derive and explain the key ideas behind a time-dependent formulation of quantum scattering theory, applicable generally to systems with a finite-range scattering potential. The scattering is initiated and probed by plane wave packets, which are localized just outside the range of the potential. The asymptotic limits of conventional scattering theory (initiation in the remote past; detection in the remote future) are not taken. Instead, the differential cross section (DCS) is obtained by projecting the scattered wave packet onto the probe plane wave packets. The projection also yields a time-dependent version of the DCS. Cuts through the wave packet, just as it exits the scattering potential, yield time-dependent and time-independent angular distributions that give a close-up picture of the scattering which complements the DCS. We have previously applied the theory to interpret experimental cross sections of chemical reactions [e.g., S. C. Althorpe, F. Fernandez-Alonso, B. D. Bean, J. D. Ayers, A. E. Pomerantz, R. N. Zare, and E. Wrede, Nature (London) 416, 67 (2002)]. This paper gives the derivation of the theory, and explains its relation to conventional scattering theory. For clarity, the derivation is restricted to spherical-particle scattering, though it may readily be extended to general multichannel systems. We illustrate the theory using a simple application to hard-sphere scattering
A Generalized Formulation of Demand Response under Market Environments
Nguyen, Minh Y.; Nguyen, Duc M.
2015-06-01
This paper presents a generalized formulation of Demand Response (DR) under deregulated electricity markets. The problem is scheduling and controls the consumption of electrical loads according to the market price to minimize the energy cost over a day. Taking into account the modeling of customers' comfort (i.e., preference), the formulation can be applied to various types of loads including what was traditionally classified as critical loads (e.g., air conditioning, lights). The proposed DR scheme is based on Dynamic Programming (DP) framework and solved by DP backward algorithm in which the stochastic optimization is used to treat the uncertainty, if any occurred in the problem. The proposed formulation is examined with the DR problem of different loads, including Heat Ventilation and Air Conditioning (HVAC), Electric Vehicles (EVs) and a newly DR on the water supply systems of commercial buildings. The result of simulation shows significant saving can be achieved in comparison with their traditional (On/Off) scheme.
International Nuclear Information System (INIS)
Rosen, N.
1979-01-01
A modification of general relativity is proposed involving a second metric tensor describing a space-time of constant curvature and associated with the fundamental rest-frame of the universe. The theory generally agrees with the Einstein theory, but gives cosmological models without singularities which can account for present observation, including helium abundance
Jackson, A. T.
1973-01-01
Reviews theoretical and experimental fundamentals of Einstein's theory of general relativity. Indicates that recent development of the theory of the continually expanding universe may lead to revision of the space-time continuum of the finite and unbounded universe. (CC)
General relativity and experiment
Damour, T.
1994-01-01
The confrontation between Einstein's theory of gravitation and experiment is summarized. Although all current experimental data are compatible with general relativity, the importance of pursuing the quest for possible deviations from Einstein's theory is emphasized.
International Nuclear Information System (INIS)
Ridgely, Charles T
2010-01-01
Many textbooks dealing with general relativity do not demonstrate the derivation of forces in enough detail. The analyses presented herein demonstrate straightforward methods for computing forces by way of general relativity. Covariant divergence of the stress-energy-momentum tensor is used to derive a general expression of the force experienced by an observer in general coordinates. The general force is then applied to the local co-moving coordinate system of a uniformly accelerating observer, leading to an expression of the inertial force experienced by the observer. Next, applying the general force in Schwarzschild coordinates is shown to lead to familiar expressions of the gravitational force. As a more complex demonstration, the general force is applied to an observer in Boyer-Lindquist coordinates near a rotating, Kerr black hole. It is then shown that when the angular momentum of the black hole goes to zero, the force on the observer reduces to the force on an observer held stationary in Schwarzschild coordinates. As a final consideration, the force on an observer moving in rotating coordinates is derived. Expressing the force in terms of Christoffel symbols in rotating coordinates leads to familiar expressions of the centrifugal and Coriolis forces on the observer. It is envisioned that the techniques presented herein will be most useful to graduate level students, as well as those undergraduate students having experience with general relativity and tensor analysis.
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''
A generalized transport-velocity formulation for smoothed particle hydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Zhang, Chi; Hu, Xiangyu Y., E-mail: xiangyu.hu@tum.de; Adams, Nikolaus A.
2017-05-15
The standard smoothed particle hydrodynamics (SPH) method suffers from tensile instability. In fluid-dynamics simulations this instability leads to particle clumping and void regions when negative pressure occurs. In solid-dynamics simulations, it results in unphysical structure fragmentation. In this work the transport-velocity formulation of Adami et al. (2013) is generalized for providing a solution of this long-standing problem. Other than imposing a global background pressure, a variable background pressure is used to modify the particle transport velocity and eliminate the tensile instability completely. Furthermore, such a modification is localized by defining a shortened smoothing length. The generalized formulation is suitable for fluid and solid materials with and without free surfaces. The results of extensive numerical tests on both fluid and solid dynamics problems indicate that the new method provides a unified approach for multi-physics SPH simulations.
Dynamics of relative motion of test particles in general relativity
International Nuclear Information System (INIS)
Bazanski, S.L.
1977-01-01
Several variational principles which lead to the first and the second geodesic deviation equations, recently formulated by the author and used for the description of the relative motion of test particles in general relativity are presented. Relations between these principles are investigated and exhibited. The Hamilton-Jacobi equation is also studied for these generalized deviations and the conservation laws appearing here are discussed
An efficient algorithm for the generalized Foldy-Lax formulation
Huang, Kai; Li, Peijun; Zhao, Hongkai
2013-02-01
Consider the scattering of a time-harmonic plane wave incident on a two-scale heterogeneous medium, which consists of scatterers that are much smaller than the wavelength and extended scatterers that are comparable to the wavelength. In this work we treat those small scatterers as isotropic point scatterers and use a generalized Foldy-Lax formulation to model wave propagation and capture multiple scattering among point scatterers and extended scatterers. Our formulation is given as a coupled system, which combines the original Foldy-Lax formulation for the point scatterers and the regular boundary integral equation for the extended obstacle scatterers. The existence and uniqueness of the solution for the formulation is established in terms of physical parameters such as the scattering coefficient and the separation distances. Computationally, an efficient physically motivated Gauss-Seidel iterative method is proposed to solve the coupled system, where only a linear system of algebraic equations for point scatterers or a boundary integral equation for a single extended obstacle scatterer is required to solve at each step of iteration. The convergence of the iterative method is also characterized in terms of physical parameters. Numerical tests for the far-field patterns of scattered fields arising from uniformly or randomly distributed point scatterers and single or multiple extended obstacle scatterers are presented.
Ray, J. R.
1982-01-01
Two theories of matter in general relativity, the fluid theory and the kinetic theory, were studied. Results include: (1) a discussion of various methods of completing the fluid equations; (2) a method of constructing charged general relativistic solutions in kinetic theory; and (3) a proof and discussion of the incompatibility of perfect fluid solutions in anisotropic cosmologies. Interpretations of NASA gravitational experiments using the above mentioned results were started. Two papers were prepared for publications based on this work.
Centennial of general relativity a celebration
2017-01-01
It has been over 100 years since the presentation of the Theory of General Relativity by Albert Einstein, in its final formulation, to the Royal Prussian Academy of Sciences. To celebrate 100 years of general relativity, World Scientific publishes this volume with a dual goal: to assess the current status of the field of general relativity in broad terms, and discuss future directions. The volume thus consists of broad overviews summarizing major developments over the past decades and their perspective contributions.
A 'general boundary' formulation for quantum mechanics and quantum gravity
International Nuclear Information System (INIS)
Oeckl, Robert
2003-01-01
I propose to formalize quantum theories as topological quantum field theories in a generalized sense, associating state spaces with boundaries of arbitrary (and possibly finite) regions of space-time. I further propose to obtain such 'general boundary' quantum theories through a generalized path integral quantization. I show how both, non-relativistic quantum mechanics and quantum field theory can be given a 'general boundary' formulation. Surprisingly, even in the non-relativistic case, features normally associated with quantum field theory emerge from consistency conditions. This includes states with arbitrary particle number and pair creation. I also note how three-dimensional quantum gravity is an example for a realization of both proposals and suggest to apply them to four-dimensional quantum gravity
Lectures on general relativity
Papapetrou, Achille
1974-01-01
This book is an elaboration of lecture notes for the graduate course on General Rela tivity given by the author at Boston University in the spring semester of 1972. It is an introduction to the subject only, as the time available for the course was limited. The author of an introduction to General Relativity is faced from the beginning with the difficult task of choosing which material to include. A general criterion as sisting in this choice is provided by the didactic character of the book: Those chapters have to be included in priority, which will be most useful to the reader in enabling him to understand the methods used in General Relativity, the results obtained so far and possibly the problems still to be solved. This criterion is not sufficient to ensure a unique choice. General Relativity has developed to such a degree, that it is impossible to include in an introductory textbook of a reasonable length even a very condensed treatment of all important problems which have been discussed unt...
Generalized formulation of free energy and application to photosynthesis
Zhang, Hwe Ik; Choi, M. Y.
2018-03-01
The origin of free energy on the earth is solar radiation. However, the amount of free energy it contains has seldom been investigated, because the free energy concept was believed to be inappropriate for a system of photons. Instead, the origin of free energy has been sought in the process of photosynthesis, imposing a limit of conversion given by the Carnot efficiency. Here we present a general formulation, capable of not only assessing accurately the available amount of free energy in the photon gas but also explaining the primary photosynthetic process more succinctly. In this formulation, the problem of "photosynthetic conversion of the internal energy of photons into the free energy of chlorophyll" is replaced by simple "free energy transduction" between the photons and chlorophyll. An analytic expression for the photosynthetic efficiency is derived and shown to deviate from the Carnot efficiency. Some predictions verifiable possibly by observation are also suggested.
General Relativity and Gravitation
Ehlers, J.; Murdin, P.
2000-11-01
The General Theory of Relativity (GR), created by Albert Einstein between 1907 and 1915, is a theory both of gravitation and of spacetime structure. It is based on the assumption that matter, via its energy-momentum, interacts with the metric of spacetime, which is considered (in contrast to Newtonian physics and SPECIAL RELATIVITY) as a dynamical field having degrees of freedom of its own (GRAVI...
Einstein algebras and general relativity
International Nuclear Information System (INIS)
Heller, M.
1992-01-01
A purely algebraic structure called an Einstein algebra is defined in such a way that every spacetime satisfying Einstein's equations is an Einstein algebra but not vice versa. The Gelfand representation of Einstein algebras is defined, and two of its subrepresentations are discussed. One of them is equivalent to the global formulation of the standard theory of general relativity; the other one leads to a more general theory of gravitation which, in particular, includes so-called regular singularities. In order to include other types of singularities one must change to sheaves of Einstein algebras. They are defined and briefly discussed. As a test of the proposed method, the sheaf of Einstein algebras corresponding to the space-time of a straight cosmic string with quasiregular singularity is constructed. 22 refs
International Nuclear Information System (INIS)
Penrose, R.
1979-01-01
Much theoretical work in General Relativity has been concerned with finding explicit solutions of Einstein field equations. Exact solutions must involve simplifying procedures which in the case of strong gravitational fields may not be valid. Computers can help but complementary to these are the global qualitative mathematics that have been introduced into relativity over the past years. These have shown that Einstein's equations together with suitable inequalities on the energy-momentum tensor can lead inevitably to space-time singularities arising, provided that some qualitative geometric criterion is satisfied. It seems that in suitable situations of gravitational collapse this criterion will be satisfied. Similarly in a cosmological setting the criterion can be applied in the reverse direction in time. There is, however, the unsolved problem in general relativity of cosmic censorship and this is discussed as a consequence of Einstein's equations. (UK)
International Nuclear Information System (INIS)
Clarke, C.
1979-01-01
The plan of the book is as follows: Chapter 1 develops special relativity in a setting and notation that can immediately be transferred to general relativity. Most of the fundamental geometrical ideas are established here. Chapter 2 gives a more conventional account of some selected applications of special relativity. Chapter 3 is the heart of the book. A geometrical model of space-time is progressively built up, motivated by physical arguments stemming from the equivalence principle, leading to Einstein's field equations. Chapter 4 deals very quickly with the simplest form of weak-field theory with application to gravitational radiation. Chapter 5 concludes the book with a fairly detailed analysis of the Schwarzschild solution, plane fronted gravitational waves, and the Robertson-Walker cosmological solutions. Exercises at the end of each chapter extend the general theory into particular applications, giving a broader picture of the scope of the subject. (author)
General Relativity and Gravitation
Ashtekar, Abhay; Berger, Beverly; Isenberg, James; MacCallum, Malcolm
2015-07-01
Part I. Einstein's Triumph: 1. 100 years of general relativity George F. R. Ellis; 2. Was Einstein right? Clifford M. Will; 3. Cosmology David Wands, Misao Sasaki, Eiichiro Komatsu, Roy Maartens and Malcolm A. H. MacCallum; 4. Relativistic astrophysics Peter Schneider, Ramesh Narayan, Jeffrey E. McClintock, Peter Mészáros and Martin J. Rees; Part II. New Window on the Universe: 5. Receiving gravitational waves Beverly K. Berger, Karsten Danzmann, Gabriela Gonzalez, Andrea Lommen, Guido Mueller, Albrecht Rüdiger and William Joseph Weber; 6. Sources of gravitational waves. Theory and observations Alessandra Buonanno and B. S. Sathyaprakash; Part III. Gravity is Geometry, After All: 7. Probing strong field gravity through numerical simulations Frans Pretorius, Matthew W. Choptuik and Luis Lehner; 8. The initial value problem of general relativity and its implications Gregory J. Galloway, Pengzi Miao and Richard Schoen; 9. Global behavior of solutions to Einstein's equations Stefanos Aretakis, James Isenberg, Vincent Moncrief and Igor Rodnianski; Part IV. Beyond Einstein: 10. Quantum fields in curved space-times Stefan Hollands and Robert M. Wald; 11. From general relativity to quantum gravity Abhay Ashtekar, Martin Reuter and Carlo Rovelli; 12. Quantum gravity via unification Henriette Elvang and Gary T. Horowitz.
Gravity, general relativity theory and alternative theories
International Nuclear Information System (INIS)
Zel'dovich, Ya.B.; Grishchuk, L.P.; Moskovskij Gosudarstvennyj Univ.
1986-01-01
The main steps in plotting the current gravitation theory and some prospects of its subsequent development are reviewed. The attention is concentrated on a comparison of the relativistic gravitational field with other physical fields. Two equivalent formulations of the general relativity (GR) - geometrical and field-theoretical - are considered in detail. It is shown that some theories of gravity constructed as the field theories at a flat background space-time are in fact just different formulations of GR and not alternative theories
A General State-Space Formulation for Online Scheduling
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Dhruv Gupta
2017-11-01
Full Text Available We present a generalized state-space model formulation particularly motivated by an online scheduling perspective, which allows modeling (1 task-delays and unit breakdowns; (2 fractional delays and unit downtimes, when using discrete-time grid; (3 variable batch-sizes; (4 robust scheduling through the use of conservative yield estimates and processing times; (5 feedback on task-yield estimates before the task finishes; (6 task termination during its execution; (7 post-production storage of material in unit; and (8 unit capacity degradation and maintenance. Through these proposed generalizations, we enable a natural way to handle routinely encountered disturbances and a rich set of corresponding counter-decisions. Thereby, greatly simplifying and extending the possible application of mathematical programming based online scheduling solutions to diverse application settings. Finally, we demonstrate the effectiveness of this model on a case study from the field of bio-manufacturing.
International Nuclear Information System (INIS)
Bini, Donato; Felice, Fernando de; Geralico, Andrea
2006-01-01
The definition of relative accelerations and strains among a set of comoving particles is studied in connection with the geometric properties of the frame adapted to a 'fiducial observer'. We find that a relativistically complete and correct definition of strains must take into account the transport law of the chosen spatial triad along the observer's congruence. We use special congruences of (accelerated) test particles in some familiar spacetimes to elucidate such a point. The celebrated idea of Szekeres' compass of inertia, arising when studying geodesic deviation among a set of free-falling particles, is here generalized to the case of accelerated particles. In doing so we have naturally contributed to the theory of relativistic gravity gradiometer. Moreover, our analysis was made in an observer-dependent form, a fact that would be very useful when thinking about general relativistic tests on space stations orbiting compact objects like black holes and also in other interesting gravitational situations
Development of Einstein's general theory of relativity
International Nuclear Information System (INIS)
Datta, B.K.
1980-01-01
Starting from Poincare's Lorentz-invariant theory of gravity formulated in 1906, development of Einstein's general theory of relativity during 1906-1916 is discussed. Three stages in this development are recognised. In the first stage during 1907-1914, Einstein tried to extend the relativity principle of uniform motion to the frames in non-uniform motion. For this purpose, he introduced the principle of equivalence which made it possible to calculate the effect of homogeneous gravitational field on arbitrary physical processes. During the second stage comprising years 1912-1914 overlapping the first stage, Einstein and Grossmann were struggling to translate physical postulates into the language of the absolute differential calculus. In the period 1915-1916, Einstein formulated the field equations of general relativity. While discussing these developmental stages, theories of gravitation formulated by Abraham, Nordstroem and Mie are also discussed. (M.G.B.)
Modern Canonical Quantum General Relativity
Thiemann, Thomas
2008-11-01
Preface; Notation and conventions; Introduction; Part I. Classical Foundations, Interpretation and the Canonical Quantisation Programme: 1. Classical Hamiltonian formulation of general relativity; 2. The problem of time, locality and the interpretation of quantum mechanics; 3. The programme of canonical quantisation; 4. The new canonical variables of Ashtekar for general relativity; Part II. Foundations of Modern Canonical Quantum General Relativity: 5. Introduction; 6. Step I: the holonomy-flux algebra [P]; 7. Step II: quantum-algebra; 8. Step III: representation theory of [A]; 9. Step IV: 1. Implementation and solution of the kinematical constraints; 10. Step V: 2. Implementation and solution of the Hamiltonian constraint; 11. Step VI: semiclassical analysis; Part III. Physical Applications: 12. Extension to standard matter; 13. Kinematical geometrical operators; 14. Spin foam models; 15. Quantum black hole physics; 16. Applications to particle physics and quantum cosmology; 17. Loop quantum gravity phenomenology; Part IV. Mathematical Tools and their Connection to Physics: 18. Tools from general topology; 19. Differential, Riemannian, symplectic and complex geometry; 20. Semianalytical category; 21. Elements of fibre bundle theory; 22. Holonomies on non-trivial fibre bundles; 23. Geometric quantisation; 24. The Dirac algorithm for field theories with constraints; 25. Tools from measure theory; 26. Elementary introduction to Gel'fand theory for Abelean C* algebras; 27. Bohr compactification of the real line; 28. Operatir -algebras and spectral theorem; 29. Refined algebraic quantisation (RAQ) and direct integral decomposition (DID); 30. Basics of harmonic analysis on compact Lie groups; 31. Spin network functions for SU(2); 32. + Functional analytical description of classical connection dynamics; Bibliography; Index.
Introduction to general relativity
Parthasarthy, R
2016-01-01
INTRODUCTION TO GENERAL RELATIVITY begins with a description of the geometry of curved space, explaining geodesics, parallel transport, covariant differentiation, geodesic deviation and spacetime symmetry by killing vectors. It then introduces Einstein's theory of gravitation followed by Schwarzschild solution with its relevance to Positive Mass theorem. The three tests for Einstein's gravity are explained. Other exact solutions such as Vaidya, Kerr and Reisner - Nordstrom metric are included. In the Chapter on cosmological solutions, a detailed description of Godel metric is provided. It then introduces five dimensional spacetime of Kaluza showing the unification of gravity with electromagnetism. This is extended to include non-Abelian gauge theory by invoking compact extra dimensions. Explicit expressions in this case for Christoffel connections and ricci tensor are derived and the higher dimensional gravity action is shown to compactification are given.
Nonlinear generalization of special relativity
International Nuclear Information System (INIS)
Winterberg, F.
1985-01-01
In Poincares axiomatic formulation special relativity is a derived consequence of a true Lorentz contraction, for a rod in absolute motion through a substratum. Furthermore, Lorentz had shown that the rod contraction can be understood by an inverse square law interaction and therefore special relativity derived from more fundamental principles. The derivation by Lorentz shows that the root of the divergence problems is the singular inverse square law. By replacing the inverse square law with a regular one through the introduction of a finite length, the author has succeeded in deriving a nonlinear generalization of special relativity which eliminates all infinities. Besides the relative velocities, these nonlinear transformation equations also contain absolute velocities against a substratum, but in the limit of small energies they go over into the linear Lorentz transformations. Depending on the smallness of the fundamental length, departures from special relativity can be observed only at very high energies. The theorem that the velocity of light is the same in all reference systems still holds and likewise the conservation laws for energy and momentum
Toward an exact formulation of special relativity
International Nuclear Information System (INIS)
Kajfosz, J.
1982-01-01
In order to clear up some controversial problems of special relativity new terms for the expression of inertial motion are introduced and it is showed that although the descriptions of two identical physical systems moving with respect to one another can be equal, their physical states differ. Some epistemological consequences of this fact are briefly discussed. (author)
Lie-isotopic generalization of the Poincare symmetry: Classical formulation
International Nuclear Information System (INIS)
Santilli, R.M.
1991-03-01
This paper is devoted to the origin and methodology of the several phenomenological predictions of deviations from Einstein's Special Relativity and related Lorentz symmetry in the behaviour of the lifetime of unstable hadrons at different speeds, that exist in the literature since the early '60's. After reviewing the background phenomenological literature, we outline the Lie-isotopic symmetry of the emerging deformations of the Minkowski metric introduced in a preceding paper, and extend the results to the construction of the full Poincare-isotopic symmetry. The local isomorphism of the Poincare-isotopic symmetry with the conventional symmetry is proved for all possible topology-preserving deformations of the Minkowski metric. In this way we establish that the phenomenological predictions of deviations recalled earlier must be specifically referred to Einstein's Special Relativity, but they cannot be referred to the Lorentz (or to the Poincare) symmetry which remains exact. Particular attention is devoted to the proof of the compatibility of the exact validity of the Special Relativity for the center-of-mass trajectory of a hadron in a particle accelerator, with conceivable deviations from the same relativity in the interior structural problem. For completeness, the analysis is complemented with a few remarks on the gravitational profile. First, we review the pioneering Lie-isotopic generalization of Einstein's Gravitation worked out by Gasperini, which possesses precisely a locally Lorentz-isotopic structure. We then restrict this theory to the interior gravitational problem in order to achieve compatibility with the particle setting. The paper concludes with a review of the need to finally conduct direct experimental measures of the lifetime of unstable hadrons at different speeds, in order to finally resolve whether Einsteins's Special and General Relativities are locally valid in the interior of hadrons, or structurally more general relativities must be worked
Conformally Coupled General Relativity
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Andrej Arbuzov
2018-02-01
Full Text Available The gravity model developed in the series of papers (Arbuzov et al. 2009; 2010, (Pervushin et al. 2012 is revisited. The model is based on the Ogievetsky theorem, which specifies the structure of the general coordinate transformation group. The theorem is implemented in the context of the Noether theorem with the use of the nonlinear representation technique. The canonical quantization is performed with the use of reparametrization-invariant time and Arnowitt– Deser–Misner foliation techniques. Basic quantum features of the models are discussed. Mistakes appearing in the previous papers are corrected.
Twistors in general relativity
International Nuclear Information System (INIS)
Penrose, R.
1987-01-01
The two most significant definitions of a twistor in (conformally) flat space-time are that given by solutions of the twistor equation and that given by α-planes in the complexification of the space-time. It is shown that these concepts are naturally dual to one another, and that they give rise to various different twistor concepts in curved space-time when referred to submanifolds of differing dimension. One of these concepts, that of 2-surface twistors, gives rise to a quasi-local definition of mass (and angular momentum). The status of this definition is explored in relation to various examples. (author)
Relativity: Special, General, and Cosmological
International Nuclear Information System (INIS)
Ellis, G F R
2005-01-01
Wolfgang Rindler is known as a writer of exceptional clarity. This quality is evident in this book as it explores in depth first special relativity, then general relativity, and finally relativistic cosmology. He bases his writing in the fundamental underlying ideas and principles that so successfully guided Einstein in his work, clarifying their nature and implications in an illuminating way with many examples. The usual suspects are there: the relativity principle and equivalence principle, the abolishing of absolute space, invariance of the speed of light, analytic and geometric representations of the Lorentz transformation, its kinematic and dynamic consequences, relativistic optics, Minkowski spacetime, energy and momentum conservation, and the Compton effect. Particularly useful is the emphasis on the unity of the whole: for example (p 63) that the kinematic effect of length shortening must imply a corresponding detailed mechanical explanation of that shortening. The tensor formulation of Maxwell's equations leads to the transformation properties of the electromagnetic field and consequent elegant derivation of the field of an infinite straight current; in this case, relativity is important even for slowly moving charges because an ordinary current moves a very big charge (p 151). General relativity is systematically introduced in stages, starting with curved spaces and moving on through static and stationary spacetimes, geodesics, and tensor calculus to the field equations. A considerable strength of the book is the careful detailed examination of the local and global geometry of the major significant solutions of the equations: the Schwarzschild spacetime and its Kruskal extension, plane gravitational waves, de sitter and anti-de Sitter spacetimes, and Robertson-Walker cosmologies. The latter includes a clear presentation of the dust and radiation model dynamics for the variety of possible cases, a detailed examination of observational relations, and
Numerical Hydrodynamics in General Relativity
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Font José A.
2003-01-01
Full Text Available The current status of numerical solutions for the equations of ideal general relativistic hydrodynamics is reviewed. With respect to an earlier version of the article, the present update provides additional information on numerical schemes, and extends the discussion of astrophysical simulations in general relativistic hydrodynamics. Different formulations of the equations are presented, with special mention of conservative and hyperbolic formulations well-adapted to advanced numerical methods. A large sample of available numerical schemes is discussed, paying particular attention to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. A comprehensive summary of astrophysical simulations in strong gravitational fields is presented. These include gravitational collapse, accretion onto black holes, and hydrodynamical evolutions of neutron stars. The material contained in these sections highlights the numerical challenges of various representative simulations. It also follows, to some extent, the chronological development of the field, concerning advances on the formulation of the gravitational field and hydrodynamic equations and the numerical methodology designed to solve them.
Between general relativity and quantum theory
International Nuclear Information System (INIS)
Rayski, J.
1982-01-01
Some possibilities of reconciling general relativity with quantum theory are discussed. The procedure of quantization is certainly not unique, but depends upon the choice of the coordinate conditions. Most versions of quantization predict the existence of gravitons, but it is also possible to formulate a quantum theory with a classical gravity whereby the expectation values of Tsub(μν) constitute the sources of the classical metric field. (author)
General relativity basics and beyond
Date, Ghanashyam
2015-01-01
A Broad Perspective on the Theory of General Relativity and Its Observable Implications General Relativity: Basics and Beyond familiarizes students and beginning researchers with the basic features of the theory of general relativity as well as some of its more advanced aspects. Employing the pedagogical style of a textbook, it includes essential ideas and just enough background material needed for readers to appreciate the issues and current research. Basics The first five chapters form the core of an introductory course on general relativity. The author traces Einstein’s arguments and presents examples of space-times corresponding to different types of gravitational fields. He discusses the adaptation of dynamics in a Riemannian geometry framework, the Einstein equation and its elementary properties, and different phenomena predicted or influenced by general relativity. Beyond Moving on to more sophisticated features of general relativity, the book presents the physical requirements of a well-defined de...
Modern Canonical Quantum General Relativity;
International Nuclear Information System (INIS)
Kiefer, Claus
2008-01-01
The open problem of constructing a consistent and experimentally tested quantum theory of the gravitational field has its place at the heart of fundamental physics. The main approaches can be roughly divided into two classes: either one seeks a unified quantum framework of all interactions or one starts with a direct quantization of general relativity. In the first class, string theory (M-theory) is the only known example. In the second class, one can make an additional methodological distinction: while covariant approaches such as path-integral quantization use the four-dimensional metric as an essential ingredient of their formalism, canonical approaches start with a foliation of spacetime into spacelike hypersurfaces in order to arrive at a Hamiltonian formulation. The present book is devoted to one of the canonical approaches-loop quantum gravity. It is named modern canonical quantum general relativity by the author because it uses connections and holonomies as central variables, which are analogous to the variables used in Yang-Mills theories. In fact, the canonically conjugate variables are a holonomy of a connection and the flux of a non-Abelian electric field. This has to be contrasted with the older geometrodynamical approach in which the metric of three-dimensional space and the second fundamental form are the fundamental entities, an approach which is still actively being pursued. It is the author's ambition to present loop quantum gravity in a way in which every step is formulated in a mathematically rigorous form. The formal Leitmotiv of loop quantum gravity is background independence. Non-gravitational theories are usually quantized on a given non-dynamical background. In contrast, due to the geometrical nature of gravity, no such background exists in quantum gravity. Instead, the notion of a background is supposed to emerge a posteriori as an approximate notion from quantum states of geometry. As a consequence, the standard ultraviolet divergences of
Cosmological tests of general relativity
International Nuclear Information System (INIS)
Hut, P.
1977-01-01
It is stated that the general relativity theory could be tested on a cosmological scale by measuring the Hubble constant and the deceleration parameter, if, in addition, everything could be known about the matter filling the universe. If, on the other hand, nothing could be presupposed about the matter content of the universe general relativity could not be tested by measuring any number of time derivatives of the scale factor. But upon making the assumption of a universe filled with non-interacting mixture of non-relativistic matter and radiation general relativity can in principle be tested by measuring the first five derivatives of the scale factor. Some general relations are here presented using this assumption. (author)
Geometrical optics in general relativity
Loinger, A.
2006-01-01
General relativity includes geometrical optics. This basic fact has relevant consequences that concern the physical meaning of the discontinuity surfaces propagated in the gravitational field - as it was first emphasized by Levi-Civita.
Cosmic frontiers of general relativity
International Nuclear Information System (INIS)
Kaufmann, W.J. III.
1977-01-01
All relevant topics in general astronomy are covered including orientation in space--time, special relativity, gravitation and general relativity, stars and stellar evolution, white dwarfs, pulsars, neutron stars, the black hole, the geometry of the Schwarzschild solution, and electrically charged and rotating black holes. Also the geometry of the Kerr solution, observations of black holes, white holes and particle creation, gravitational waves and lenses, exploding galaxies and massive and primordial black holes are discussed
Numerical Hydrodynamics and Magnetohydrodynamics in General Relativity
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Font José A.
2008-09-01
Full Text Available This article presents a comprehensive overview of numerical hydrodynamics and magnetohydrodynamics (MHD in general relativity. Some significant additions have been incorporated with respect to the previous two versions of this review (2000, 2003, most notably the coverage of general-relativistic MHD, a field in which remarkable activity and progress has occurred in the last few years. Correspondingly, the discussion of astrophysical simulations in general-relativistic hydrodynamics is enlarged to account for recent relevant advances, while those dealing with general-relativistic MHD are amply covered in this review for the first time. The basic outline of this article is nevertheless similar to its earlier versions, save for the addition of MHD-related issues throughout. Hence, different formulations of both the hydrodynamics and MHD equations are presented, with special mention of conservative and hyperbolic formulations well adapted to advanced numerical methods. A large sample of numerical approaches for solving such hyperbolic systems of equations is discussed, paying particular attention to solution procedures based on schemes exploiting the characteristic structure of the equations through linearized Riemann solvers. As previously stated, a comprehensive summary of astrophysical simulations in strong gravitational fields is also presented. These are detailed in three basic sections, namely gravitational collapse, black-hole accretion, and neutron-star evolutions; despite the boundaries, these sections may (and in fact do overlap throughout the discussion. The material contained in these sections highlights the numerical challenges of various representative simulations. It also follows, to some extent, the chronological development of the field, concerning advances in the formulation of the gravitational field, hydrodynamics and MHD equations and the numerical methodology designed to solve them. To keep the length of this article reasonable
The power of general relativity
International Nuclear Information System (INIS)
Clifton, Timothy; Barrow, John D.
2005-01-01
We study the cosmological and weak-field properties of theories of gravity derived by extending general relativity by means of a Lagrangian proportional to R 1+δ . This scale-free extension reduces to general relativity when δ→0. In order to constrain generalizations of general relativity of this power class, we analyze the behavior of the perfect-fluid Friedmann universes and isolate the physically relevant models of zero curvature. A stable matter-dominated period of evolution requires δ>0 or δ -19 assuming that Mercury follows a timelike geodesic. The combination of these observational constraints leads to the overall bound 0≤δ -19 on theories of this type
Advanced mechanics and general relativity an introduction to general relativity
Franklin, Joel
2010-01-01
Aimed at advanced undergraduates with background knowledge of classical mechanics and electricity and magnetism, this textbook presents both the particle dynamics relevant to general relativity, and the field dynamics necessary to understand the theory. Focusing on action extremization, the book develops the structure and predictions of general relativity by analogy with familiar physical systems. Topics ranging from classical field theory to minimal surfaces and relativistic strings are covered in a homogeneous manner. Nearly 150 exercises and numerous examples throughout the textbook enable students to test their understanding of the material covered.
Generalized Moshinsky bracket recurrence relations
International Nuclear Information System (INIS)
Bevelacqua, J.J.
1979-01-01
Recurrence relations for generalized Talmi-Moshinsky brackets are derived. These relations permit the generation of transformation brackets once appropriate starting brackets are determined. The savings in computer time, when compared with generating brackets individually, is at least a factor of 10 for brackets with radial quantum numbers as large as 9 and angular quantum numbers as large as 2. (author)
Spinning fluids in general relativity
Ray, J. R.; Smalley, L. L.
1982-01-01
General relativity field equations are employed to examine a continuous medium with internal spin. A variational principle formerly applied in the special relativity case is extended to the general relativity case, using a tetrad to express the spin density and the four-velocity of the fluid. An energy-momentum tensor is subsequently defined for a spinning fluid. The equations of motion of the fluid are suggested to be useful in analytical studies of galaxies, for anisotropic Bianchi universes, and for turbulent eddies.
Pseudo-complex general relativity
Hess, Peter O; Greiner, Walter
2016-01-01
This volume presents an pseudo-complex extension of General Relativity which addresses these issues and presents proposals for experimental examinations in strong fields near a large mass. General Relativity is a beautiful and well tested theory of gravitation. Nevertheless, it implies conceptual problems like the creation of singularities (Black Holes) as a result of the collapse of large masses, or the appearance of event horizons which exclude parts of the space-time from the observation of external observers. The mathematical and geometrical foundations of this extension are displayed in detail, and applications including orbits and accretion disks around large central masses, neutron stars or cosmological models are introduced. Calculations both for classical and extended applications are often executed in the form of problems with extensive solutions, which makes this volume also a valuable resource for any student of General Relativity.
Bimetric general relativity and cosmology
International Nuclear Information System (INIS)
Rosen, N.
1980-01-01
A modification of the general relativity theory is proposed (bimetric general relativity) in which, in addition to the usual metric tensor gsub(μupsilon) describing the space-time geometry and gravitation, there exists also a background metric tensor γsub(μupsilon). The latter describes the space-time of the universe if no matter were present and is taken to correspond to a space-time of constant curvature with positive spatial curvature (k = 1). Field equations are obtained, and these agree with the Einstein equations for systems that are small compared to the size of the universe, such as the solar system. Energy considerations lead to a generalized form of the De Donder condition. Simple isotropic closed models of the universe can be set up which first contract and then expand without going through a singular state. It is suggested that the maximum density of the universe was of the order of c 5 -h -1 G -2 approximately 10 93 g/cm 3 . The expansion from such a high-density state is similar to that from the singular state ('big bang') of the general relativity models. In the case of the dust-filled model the parameters can be fitted to present cosmological data. Using the radiation-filled model to describe the early history of the universe, the cosmic abundance of helium and other light elements can be accounted for in the same way as in ordinary general relativity. (author)
Conformal covariance of general relativity
International Nuclear Information System (INIS)
Ionescu-Pallas, N.; Gottlieb, I.
1980-01-01
The Einstein's equations of General Relativity are written in a conformal metric, resulting as a consequence of geometrizing the pressure forces. Accordingly, the trajectory of a test body pursues a geodetic line even inside the source of gravitational field. Moreover, the pressure, entering the perfect fluid scheme, may be replaced by a certain scalar interaction. This new manner of interpreting General Relativity is then applied to Cosmology, in order to build up a model of Universe whose static limit should coincide with that of Einstein. At the same time, the cosmological constant is connected to the scalar interaction acquiring a plausible explanation. (author)
General relativity and gravitational waves
Weber, Johanna
1961-01-01
An internationally famous physicist and electrical engineer, the author of this text was a pioneer in the investigation of gravitational waves. Joseph Weber's General Relativity and Gravitational Waves offers a classic treatment of the subject. Appropriate for upper-level undergraduates and graduate students, this text remains ever relevant. Brief but thorough in its introduction to the foundations of general relativity, it also examines the elements of Riemannian geometry and tensor calculus applicable to this field.Approximately a quarter of the contents explores theoretical and experimenta
Distortions in power spectra of digitized signals - I: General formulations
International Nuclear Information System (INIS)
Njau, E.C.
1982-04-01
When a continuous signal f(t) is digitized and then spectrally analysed, the resultant energy spectral density R(ω) is given as R(ω) = |F(ω) * D(ω)| 2 , where F(ω) is the exact Fourier transform of f(t), D(ω) is the exact Fourier transform of the digitization process and * denotes convolution operation. A notable practical problem in spectral analysis is how to adequately decouple D(ω) from R(ω) and hence obtain the exact energy spectral density of f(t), i.e. |F(ω)| 2 , since R(ω) → |F(ω)| 2 only if D(ω) → delta(ω) or (under certain conditions) when D(ω) → delta(ω-ω 0 ) or if D(ω) → Σsub(n) delta(ω-ωsub(n)), where the latter is a sufficiently spaced series of delta functions and ωsub(j) is constant for a given j. A solution to this problem requires, among others, thorough understanding of D(ω), how it relates to F(ω) and hence the manner or degree to which D(ω) distorts or contaminates F(ω) to form R(ω). In this paper, we have developed exact analytical expressions of D(ω) that are well related to the corresponding F(ω) in the cases when f(t) is a simple sinusoid as well as when it is in the form of a more complex function. It is established that in either of these cases, D(ω) is a clear function of the salient parameters of both f(t) and F(ω). The contents of this paper are used in Part II to examine the manner and extent to which D(ω) causes distortions in R(ω) under given conditions, and also to establish a procedure by which such distortions may be decoupled from a practically computed R(ω). Other related issues such as frequency shifts in computed power spectra are also discussed therein. (author)
Generalized Lee-Wick formulation from higher derivative field theories
International Nuclear Information System (INIS)
Cho, Inyong; Kwon, O-Kab
2010-01-01
We study a higher derivative (HD) field theory with an arbitrary order of derivative for a real scalar field. The degree of freedom for the HD field can be converted to multiple fields with canonical kinetic terms up to the overall sign. The Lagrangian describing the dynamics of the multiple fields is known as the Lee-Wick (LW) form. The first step to obtain the LW form for a given HD Lagrangian is to find an auxiliary field (AF) Lagrangian which is equivalent to the original HD Lagrangian up to the quantum level. Until now, the AF Lagrangian has been studied only for N=2 and 3 cases, where N is the number of poles of the two-point function of the HD scalar field. We construct the AF Lagrangian for arbitrary N. By the linear combinations of AF fields, we also obtain the corresponding LW form. We find the explicit mapping matrices among the HD fields, the AF fields, and the LW fields. As an exercise of our construction, we calculate the relations among parameters and mapping matrices for N=2, 3, and 4 cases.
General relativity 50 years old
1966-01-01
In May 1916, 'The Foundations of General Relativity Theory' by Albert Einstein was published in 'Annalen der Physik'. Fifty years later, this major contribution to scientific thought still has a rather isolated position with respect to the main-stream of scientific theory. (In contrast, the Special Theory of Relativity is one of the cornerstones of sub-nuclear physics.) To mark the anniversary of the publication of Einstein's paper a theoretician from CERN discusses the theory and its present status.
Quantum mechanics from general relativity
International Nuclear Information System (INIS)
Sachs, M.
1986-01-01
A generalization of quantum mechanics is demonstrated in the context of general relativity, following from a generally covariant field theory of inertia. Nonrelativistically, the formalism corresponds with linear quantum mechanics. In the limit of special relativity, nonlinearity remains and several new features are derived: (1) Particle-antiparticle pairs do not annihilate; an exact bound state solution is derived corresponding with all experimental facts about annihilation/creation - which, in approximation, gives the blackbody radiation spectrum for a sea of such pairs. (2) A result is proven, without approximation, that is physically equivalent to the Pauli exclusion principle - which, in linear approximation, gives the totally antisymmetrised many-body wave function and Fermi-Dirac statistics. (3) The hydrogen spectrum is derived, including the Lamb shifts, in agreement with experiment; new results are found for high energy electron-proton scattering. (4) Finally, several applications to the elementary particle domain are demonstrated, in agreement with results from experimental high energy physics. (Auth.)
General Relativity: horizons for tests
Yatskiv, Ya. S.; Alexandrov, A. N.; Vavilova, I. B.; Zhdanov, V. I.; Zhuk, A. I.; Kudrya, Yu. N.; Parnovsky, S. L.; Fedorova, E. V.; Khmil, S. V.
2013-12-01
Theoretical basis of the General Relativity Theory (GRT), its experimental tests as well as GRT applications are briefly summarized taking into account the results of the last decade. The monograph addresses scientists, post-graduated students, and students specialized in the natural sciences as well as everyone who takes an interest in GRT.
General relativity and dark matter
International Nuclear Information System (INIS)
Pestov, A.B.
1993-01-01
It is shown that from the first principles of General Relativity it follows that there exists a new type of interactions which are tightly connected with the gravitational interactions. New particles representing a new form of interactions do not interact electromagnetically, strongly and weakly with the known elementary particles. Physics of the new particles is defined by the Planck scales. (author.). 9 refs
General Relativity: Geometry Meets Physics
Thomsen, Dietrick E.
1975-01-01
Observing the relationship of general relativity and the geometry of space-time, the author questions whether the rest of physics has geometrical explanations. As a partial answer he discusses current research on subatomic particles employing geometric transformations, and cites the existence of geometrical definitions of physical quantities such…
Modified General Relativity and Cosmology
Abdel-Rahman, A.-M. M.
1997-10-01
Aspects of the modified general relativity theory of Rastall, Al-Rawaf and Taha are discussed in both the radiation- and matter-dominated flat cosmological models. A nucleosynthesis constraint on the theory's free parameter is obtained and the implication for the age of the Universe is discussed. The consistency of the modified matter- dominated model with the neoclassical cosmological tests is demonstrated.
Algebraic computing in general relativity
International Nuclear Information System (INIS)
D'Inverno, R.A.
1975-01-01
The purpose of this paper is to bring to the attention of potential users the existence of algebraic computing systems, and to illustrate their use by reviewing a number of problems for which such a system has been successfully used in General Relativity. In addition, some remarks are included which may be of help in the future design of these systems. (author)
Cosmological models in general relativity
Indian Academy of Sciences (India)
Cosmological models in general relativity. B B PAUL. Department of Physics, Nowgong College, Nagaon, Assam, India. MS received 4 October 2002; revised 6 March 2003; accepted 21 May 2003. Abstract. LRS Bianchi type-I space-time filled with perfect fluid is considered here with deceler- ation parameter as variable.
Dimensional Analysis and General Relativity
Lovatt, Ian
2009-01-01
Newton's law of gravitation is a central topic in the first-year physics curriculum. A lecturer can go beyond the physical details and use the history of gravitation to discuss the development of scientific ideas; unfortunately, the most recent chapter in this history, general relativity, is not covered in first-year courses. This paper discusses…
The genesis of general relativity
Norton, John; Renn, Jürgen; Sauer, Tilman; Stachel, John
2007-01-01
This four-volume work represents the most comprehensive documentation and study of the creation of general relativity; one of the fundamental physical theories of the 20th century. It comprises key sources from Einstein and others who from the late 19th to the early 20th century contributed to this monumental development. Some of these sources are presented here in translation for the first time. Einstein’s famous Zurich notebook, which documents the pivotal steps toward general relativity, is reproduced here for the first time and transcribed in its entirety. The volumes offer detailed commentaries and analyses of these sources that are based on a close reading of these documents supplemented by interpretations by the leading historians of relativity. All in all, the facets of this work, based on more than a decade of research, combine to constitute one of the most in-depth studies of a scientific revolution ever written.
Partial Differential Equations in General Relativity
International Nuclear Information System (INIS)
Choquet-Bruhat, Yvonne
2008-01-01
General relativity is a physical theory basic in the modeling of the universe at the large and small scales. Its mathematical formulation, the Einstein partial differential equations, are geometrically simple, but intricate for the analyst, involving both hyperbolic and elliptic PDE, with local and global problems. Many problems remain open though remarkable progress has been made recently towards their solutions. Alan Rendall's book states, in a down-to-earth form, fundamental results used to solve different types of equations. In each case he gives applications to special models as well as to general properties of Einsteinian spacetimes. A chapter on ODE contains, in particular, a detailed discussion of Bianchi spacetimes. A chapter entitled 'Elliptic systems' treats the Einstein constraints. A chapter entitled 'Hyperbolic systems' is followed by a chapter on the Cauchy problem and a chapter 'Global results' which contains recently proved theorems. A chapter is dedicated to the Einstein-Vlasov system, of which the author is a specialist. On the whole, the book surveys, in a concise though precise way, many essential results of recent interest in mathematical general relativity, and it is very clearly written. Each chapter is followed by an up to date bibliography. In conclusion, this book will be a valuable asset to relativists who wish to learn clearly-stated mathematical results and to mathematicians who want to penetrate into the subtleties of general relativity, as a mathematical and physical theory. (book review)
Partial Differential Equations in General Relativity
Energy Technology Data Exchange (ETDEWEB)
Choquet-Bruhat, Yvonne
2008-09-07
General relativity is a physical theory basic in the modeling of the universe at the large and small scales. Its mathematical formulation, the Einstein partial differential equations, are geometrically simple, but intricate for the analyst, involving both hyperbolic and elliptic PDE, with local and global problems. Many problems remain open though remarkable progress has been made recently towards their solutions. Alan Rendall's book states, in a down-to-earth form, fundamental results used to solve different types of equations. In each case he gives applications to special models as well as to general properties of Einsteinian spacetimes. A chapter on ODE contains, in particular, a detailed discussion of Bianchi spacetimes. A chapter entitled 'Elliptic systems' treats the Einstein constraints. A chapter entitled 'Hyperbolic systems' is followed by a chapter on the Cauchy problem and a chapter 'Global results' which contains recently proved theorems. A chapter is dedicated to the Einstein-Vlasov system, of which the author is a specialist. On the whole, the book surveys, in a concise though precise way, many essential results of recent interest in mathematical general relativity, and it is very clearly written. Each chapter is followed by an up to date bibliography. In conclusion, this book will be a valuable asset to relativists who wish to learn clearly-stated mathematical results and to mathematicians who want to penetrate into the subtleties of general relativity, as a mathematical and physical theory. (book review)
Testing general relativity on accelerators
Directory of Open Access Journals (Sweden)
Tigran Kalaydzhyan
2015-11-01
Full Text Available Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable – maximal energy of the scattered photons – would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.
Quantum information and general relativity
International Nuclear Information System (INIS)
Peres, A.
2004-01-01
The Einstein-Podolsky-Rosen paradox (1935) is reexamined in the light of Shannon's information theory (1948). The EPR argument did not take into account that the observers' information was localized, like any other physical object. General relativity introduces new problems: there are horizons which act as on-way membranes for the propagation of quantum information, in particular black holes which act like sinks. (Abstract Copyright [2004], Wiley Periodicals, Inc.)
Quantum information and general relativity
Energy Technology Data Exchange (ETDEWEB)
Peres, A. [Technion, Israel Institute of Technology, Haifa (Israel)
2004-12-01
The Einstein-Podolsky-Rosen paradox (1935) is reexamined in the light of Shannon's information theory (1948). The EPR argument did not take into account that the observers' information was localized, like any other physical object. General relativity introduces new problems: there are horizons which act as on-way membranes for the propagation of quantum information, in particular black holes which act like sinks. (Abstract Copyright [2004], Wiley Periodicals, Inc.)
Quantum information and general relativity
Peres, Asher
2004-01-01
The Einstein-Podolsky-Rosen paradox (1935) is reexamined in the light of Shannon's information theory (1948). The EPR argument did not take into account that the observers' information was localized, like any other physical object. General relativity introduces new problems: there are horizons which act as one-way membranes for the propagation of quantum information, in particular black holes which act like sinks.
Quantum information and general relativity
Peres, A.
2004-11-01
The Einstein-Podolsky-Rosen paradox (1935) is reexamined in the light of Shannon's information theory (1948). The EPR argument did not take into account that the observers' information was localized, like any other physical object. General relativity introduces new problems: there are horizons which act as on-way membranes for the propagation of quantum information, in particular black holes which act like sinks.
Bubble collisions in general relativity
International Nuclear Information System (INIS)
Siklos, S.T.C.; Wu, Z.C.; University of Science and Technology of China, Hofei, Anhwei)
1983-01-01
The collision of two bubbles of true vacuum in a background of false vacuum is considered in the context of General Relativity. It is found that in the thin wall approximation, the problem, can be solved exactly. The region to the future of the collision is described by the pseudo-Schwarzschild de Sitter metric. The parameters in this metric are found by solving the junction conditions at each collision. (author)
General formulation of standard model the standard model is in need of new concepts
International Nuclear Information System (INIS)
Khodjaev, L.Sh.
2001-01-01
The phenomenological basis for formulation of the Standard Model has been reviewed. The Standard Model based on the fundamental postulates has been formulated. The concept of the fundamental symmetries has been introduced: To look for not fundamental particles but fundamental symmetries. By searching of more general theory it is natural to search first of all global symmetries and than to learn consequence connected with the localisation of this global symmetries like wise of the standard Model
Gravitation. [Book on general relativity
Misner, C. W.; Thorne, K. S.; Wheeler, J. A.
1973-01-01
This textbook on gravitation physics (Einstein's general relativity or geometrodynamics) is designed for a rigorous full-year course at the graduate level. The material is presented in two parallel tracks in an attempt to divide key physical ideas from more complex enrichment material to be selected at the discretion of the reader or teacher. The full book is intended to provide competence relative to the laws of physics in flat space-time, Einstein's geometric framework for physics, applications with pulsars and neutron stars, cosmology, the Schwarzschild geometry and gravitational collapse, gravitational waves, experimental tests of Einstein's theory, and mathematical concepts of differential geometry.
Results from Numerical General Relativity
Baker, John G.
2011-01-01
For several years numerical simulations have been revealing the details of general relativity's predictions for the dynamical interactions of merging black holes. I will review what has been learned of the rich phenomenology of these mergers and the resulting gravitational wave signatures. These wave forms provide a potentially observable record of the powerful astronomical events, a central target of gravitational wave astronomy. Asymmetric radiation can produce a thrust on the system which may accelerate the single black hole resulting from the merger to high relative velocity.
A generalized Principle of Relativity
International Nuclear Information System (INIS)
Felice, Fernando de; Preti, Giovanni
2009-01-01
The Theory of Relativity stands as a firm groundstone on which modern physics is founded. In this paper we bring to light an hitherto undisclosed richness of this theory, namely its admitting a consistent reformulation which is able to provide a unified scenario for all kinds of particles, be they lightlike or not. This result hinges on a generalized Principle of Relativity which is intrinsic to Einstein's theory - a fact which went completely unnoticed before. The road leading to this generalization starts, in the very spirit of Relativity, from enhancing full equivalence between the four spacetime directions by requiring full equivalence between the motions along these four spacetime directions as well. So far, no measurable spatial velocity in the direction of the time axis has ever been defined, on the same footing of the usual velocities - the 'space-velocities' - in the local three-space of a given observer. In this paper, we show how Relativity allows such a 'time-velocity' to be defined in a very natural way, for any particle and in any reference frame. As a consequence of this natural definition, it also follows that the time- and space-velocity vectors sum up to define a spacelike 'world-velocity' vector, the modulus of which - the world-velocity - turns out to be equal to the Maxwell's constant c, irrespective of the observer who measures it. This measurable world-velocity (not to be confused with the space-velocities we are used to deal with) therefore represents the speed at which all kinds of particles move in spacetime, according to any observer. As remarked above, the unifying scenario thus emerging is intrinsic to Einstein's Theory; it extends the role traditionally assigned to Maxwell's constant c, and can therefore justly be referred to as 'a generalized Principle of Relativity'.
Simple recursion relations for general field theories
International Nuclear Information System (INIS)
Cheung, Clifford; Shen, Chia-Hsien; Trnka, Jaroslav
2015-01-01
On-shell methods offer an alternative definition of quantum field theory at tree-level, replacing Feynman diagrams with recursion relations and interaction vertices with a handful of seed scattering amplitudes. In this paper we determine the simplest recursion relations needed to construct a general four-dimensional quantum field theory of massless particles. For this purpose we define a covering space of recursion relations which naturally generalizes all existing constructions, including those of BCFW and Risager. The validity of each recursion relation hinges on the large momentum behavior of an n-point scattering amplitude under an m-line momentum shift, which we determine solely from dimensional analysis, Lorentz invariance, and locality. We show that all amplitudes in a renormalizable theory are 5-line constructible. Amplitudes are 3-line constructible if an external particle carries spin or if the scalars in the theory carry equal charge under a global or gauge symmetry. Remarkably, this implies the 3-line constructibility of all gauge theories with fermions and complex scalars in arbitrary representations, all supersymmetric theories, and the standard model. Moreover, all amplitudes in non-renormalizable theories without derivative interactions are constructible; with derivative interactions, a subset of amplitudes is constructible. We illustrate our results with examples from both renormalizable and non-renormalizable theories. Our study demonstrates both the power and limitations of recursion relations as a self-contained formulation of quantum field theory.
Homothetic motions in general relativity
International Nuclear Information System (INIS)
McIntosh, C.B.G.
1976-01-01
Properties of homothetic or self-similar motions in general relativity are examined with particular reference to vacuum and perfect-fluid space-times. The role of the homothetic bivector with components Hsub((a;b)) formed from the homothetic vector H is discussed in some detail. It is proved that a vacuum space-time only admits a nontrivial homothetic motion if the homothetic vector field is non-null and is not hypersurface orthogonal. As a subcase of a more general result it is shown that a perfect-fluid space-time cannot admit a non-trivial homothetic vector which is orthogonal to the fluid velocity 4-vector. (author)
General relativity and gravitation, 1989
International Nuclear Information System (INIS)
Ashby, N.; Bartlett, D.F.; Wyss, W.
1990-01-01
This volume records the lectures and symposia of the 12th International Conference on General Relativity and Gravitation. Plenary lecturers reviewed the major advances since the previous conference in 1986. The reviews cover classical and quantum theory of gravity, colliding gravitational waves, gravitational lensing, relativistic effects on pulsars, tests of the inverse square law, numerical relativity, cosmic microwave background radiation, experimental tests of gravity theory, gravitational wave detectors, and cosmology. The plenary lectures are complemented by summaries of symposia, provided by the chairmen. Almost 700 contributed papers were presented at these and they cover an even wider range of topics than the plenary talks. The book provides a comprehensive guide to research activity in both experimental and theoretical gravitation and its applications in astrophysics and cosmology. It will be essential reading for research workers in these fields, as well as theoretical and experimental physicists, astronomers, and mathematicians who wish to be acquainted with modern developments in gravitational theory and general relativity. All the papers and summaries of the workshop sessions are indexed separately. (16 united talks, 20 workshop sessions). (author)
An introduction to the general boundary formulation of quantum field theory
International Nuclear Information System (INIS)
Colosi, Daniele
2015-01-01
We give a brief introduction to the so-called general boundary formulation (GBF) of quantum theory. This new axiomatic formulation provides a description of the quantum dynamics which is manifestly local and does not rely on a metric background structure for its definition. We present the basic ingredients of the GBF, in particular we review the core axioms that assign algebraic structures to geometric ones, the two quantisation schemes so far developed for the GBF and the probability interpretation which generalizes the standard Born rule. Finally we briefly discuss some of the results obtained studying specific quantum field theories within the GBF. (paper)
70 years of the general theory of relativity
International Nuclear Information System (INIS)
Castro Diaz-Balart, F.; Cabezas Solorzano, R.
1986-06-01
In view of the 70th anniversary of the discovery of the General Theory of Relativity, an analysis was made of the special and general theories. The basic postulates, their consequences in the formulation of the theories, the main results, some aspects related to the experimental verification and its applications are presented, as are some elements of the mathematical formalism of the theories, to facilitate the logical interrelationships between its results and consequences. (author)
The renaissance of general relativity
International Nuclear Information System (INIS)
Will, C.
1989-01-01
A historical evaluation of Einstein's theory of general relativity is presented, including the three classical tests of the theory. Gravitation is shown to be a ''curved spacetime'' phenomenon, particularly if the Einstein equivalence principle (EEP) is true. The article traces the success and failures of the theory over the years and up to the present. The concept of gravitation waves was, for example, strengthened by the discovery of a binary pulsar in 1974. The author describes the theory's relevance to neutron stars and black holes and its role in establishing the hot big bang model of cosmological evolution. The article concludes by considering the possibility of antigravity and how gravitational calculations can be done by computer because of the large number of variables in the calculations. (U.K.)
General relativity: An erfc metric
Plamondon, Réjean
2018-06-01
This paper proposes an erfc potential to incorporate in a symmetric metric. One key feature of this model is that it relies on the existence of an intrinsic physical constant σ, a star-specific proper length that scales all its surroundings. Based thereon, the new metric is used to study the space-time geometry of a static symmetric massive object, as seen from its interior. The analytical solutions to the Einstein equation are presented, highlighting the absence of singularities and discontinuities in such a model. The geodesics are derived in their second- and first-order differential formats. Recalling the slight impact of the new model on the classical general relativity tests in the solar system, a number of facts and open problems are briefly revisited on the basis of a heuristic definition of σ. A special attention is given to gravitational collapses and non-singular black holes.
Spacecraft Tests of General Relativity
Anderson, John D.
1997-01-01
Current spacecraft tests of general relativity depend on coherent radio tracking referred to atomic frequency standards at the ground stations. This paper addresses the possibility of improved tests using essentially the current system, but with the added possibility of a space-borne atomic clock. Outside of the obvious measurement of the gravitational frequency shift of the spacecraft clock, a successor to the suborbital flight of a Scout D rocket in 1976 (GP-A Project), other metric tests would benefit most directly by a possible improved sensitivity for the reduced coherent data. For purposes of illustration, two possible missions are discussed. The first is a highly eccentric Earth orbiter, and the second a solar-conjunction experiment to measure the Shapiro time delay using coherent Doppler data instead of the conventional ranging modulation.
Machian effects in general relativity
International Nuclear Information System (INIS)
Embacher, F.
1988-01-01
As a consequence of Mach's principle, rotating matter should cause local inertial frames or gyroscopes in its vicinity to undergo a small rotation which is not present in the Newtonian picture. H. Thirring and J. Lense were the first to derive similar predictions from the field equations of general relativity. Since these early days of relativity, a lot of exact and approximate solutions to Einstein's equations have been examined under this point of view. The qualitative features of Machian effects are most easily demonstrated in the cylinder symmetric case, where some exact results are available. For example, space-time is flat inside a uniformly rotating matter shell, and the rotation of this interior with respect to 'infinity' (the distant stars) has a clear meaning. In the more realistic case of what happens near a massive rotating star, one is forced to perform certain approximations. In modern language, Machian effects are described in terms of the twist of timelike killing vector fields. In the linearized theory, the equations that determine the Machian structure generated by a given matter distribution, resemble to some extent those of classical electrodynamics. This correspondence provides a pedagogical approach how to compute the quantitative extent of inertial frame 'dragging'. 6 refs., 5 figs. (Author)
Angular momentum in general relativity
International Nuclear Information System (INIS)
Prior, C.R.
1977-01-01
The definition of angular momentum proposed in part I of this series (Prior. Proc. R. Soc. Lond.; A354:379 (1977)) is investigated when applied to rotating black holes. It is shown how to use the formula to evaluate the angular momentum of a stationary black hole. This acts as a description of a background space on which the effect of first matter and then gravitational perturbations is considered. The latter are of most interest and the rate of change of angular momentum, dJ/dt, is found as an expression in the shear induced in the event horizon by the perturbation and in its time integral. Teukolsky's solutions (Astrophys. J.; 185:635 (1973)) for the perturbed component of the Weyl tensor are then used to find this shear and hence to give an exact answer for dJ/dt. One of the implications of the result is a direct verification of Bekenstein's formula (Phys. Rev.; 7D:949 (1973)) relating in a simple way the rate of change of angular momentum to the rate of change of mass caused by a plane wave. A more general expression is also given for dM/dt. Considering only stationary perturbations, it is shown how to generalize the definition of angular momentum so as to include information about its direction as well. Three problems are particularly discussed - a single moon, two or more moons and a ring of matter causing the perturbation - since they provide illustrations of all the main features of the black hole's behaviour. In every case it is found that the black hole realigns its axis of rotation so that the final configuration is axisymmetric if possible; otherwise is slows down completely to reach a static state. (author)
Survey on Dirac equation in general relativity theory
International Nuclear Information System (INIS)
Paillere, P.
1984-10-01
Starting from an infinitesimal transformation expressed with a Killing vector and using systematically the formalism of the local tetrades, we show that, in the area of the general relativity, the Dirac equation may be formulated only versus the four local vectors which determine the gravitational potentials, their gradients and the 4-vector potential of the electromagnetic field [fr
Einstein and Hilbert: The creation of general relativity
International Nuclear Information System (INIS)
Todorov, I.T.
1992-12-01
It took eight years after Einstein announced the basic physical ideas behind the relativistic gravity theory before the proper mathematical formulation of general-relativity was mastered. The efforts of the greatest physicist and of the greatest mathematician of the time was involved and reached a breathtaking concentration during the last month of the work. (author)
Geometric quantization and general relativity
International Nuclear Information System (INIS)
Souriau, J.-M.
1977-01-01
The purpose of geometric quantization is to give a rigorous mathematical content to the 'correspondence principle' between classical and quantum mechanics. The main tools are borrowed on one hand from differential geometry and topology (differential manifolds, differential forms, fiber bundles, homology and cohomology, homotopy), on the other hand from analysis (functions of positive type, infinite dimensional group representations, pseudo-differential operators). Some satisfactory results have been obtained in the study of dynamical systems, but some fundamental questions are still waiting for an answer. The 'geometric quantization of fields', where some further well known difficulties arise, is still in a preliminary stage. In particular, the geometric quantization on the gravitational field is still a mere project. The situation is even more uncertain due to the fact that there is no experimental evidence of any quantum gravitational effect which could give us a hint towards what we are supposed to look for. The first level of both Quantum Theory, and General Relativity describes passive matter: influence by the field without being a source of it (first quantization and equivalence principle respectively). In both cases this is only an approximation (matter is always a source). But this approximation turns out to be the least uncertain part of the description, because on one hand the first quantization avoids the problems of renormalization and on the other hand the equivalence principle does not imply any choice of field equations (it is known that one can modify Einstein equations at short distances without changing their geometrical properties). (Auth.)
The tensorial conservation law in general relativity
International Nuclear Information System (INIS)
Zhao, M.G.
1984-01-01
A general tensorial conservation law is formulated by starting from the invariance of the gravitational Lagrangian density. Utilising this new formula, the author derives some reasonable results for the mass-energy distribution which are in accordance with the Newtonian formulae. (author)
Introduction to general relativity, black holes and cosmology
Choquet-Bruhat, Yvonne
2015-01-01
General Relativity is a beautiful geometric theory, simple in its mathematical formulation but leading to numerous consequences with striking physical interpretations: gravitational waves, black holes, cosmological models, and so on. This introductory textbook is written for mathematics students interested in physics and physics students interested in exact mathematical formulations (or for anyone with a scientific mind who is curious to know more of the world we live in), recent remarkable experimental and observational results which confirm the theory are clearly described and no specialised physics knowledge is required. The mathematical level of Part A is aimed at undergraduate students and could be the basis for a course on General Relativity. Part B is more advanced, but still does not require sophisticated mathematics. Based on Yvonne Choquet-Bruhat's more advanced text, General Relativity and the Einstein Equations, the aim of this book is to give with precision, but as simply as possible, the found...
A general theory of quantum relativity
International Nuclear Information System (INIS)
Minic, Djordje; Tze, C.-H.
2004-01-01
The geometric form of standard quantum mechanics is compatible with the two postulates: (1) the laws of physics are invariant under the choice of experimental setup and (2) every quantum observation or event is intrinsically statistical. These postulates remain compatible within a background independent extension of quantum theory with a local intrinsic time implying the relativity of the concept of a quantum event. In this extension the space of quantum events becomes dynamical and only individual quantum events make sense observationally. At the core of such a general theory of quantum relativity is the three-way interplay between the symplectic form, the dynamical metric and non-integrable almost complex structure of the space of quantum events. Such a formulation provides a missing conceptual ingredient in the search for a background independent quantum theory of gravity and matter. The crucial new technical element in our scheme derives from a set of recent mathematical results on certain infinite-dimensional almost Kahler manifolds which replace the complex projective spaces of standard quantum mechanics
Zorn algebra in general relativity
International Nuclear Information System (INIS)
Oliveira, C.G.; Maia, M.D.
The covariant differential properties of the split Cayley subalgebra of local real quaternion tetrads is considered. Referred to this local quaternion tetrad several geometrical objects are given in terms of Zorn-Weyl matrices. Associated to a pair of real null vectors we define two-component spinor fields over the curved space and the associated Zorn-Weyl matrices which satisfy the Dirac equation written in terms of the Zorn algebra. The formalism is generalized by considering a field of complex tetrads defining a Hermitian second rank tensor. The real part of this tensor describes the gravitational potentials and the imaginary part the electromagnetic potentials in the Lorentz gauge. The motion of a charged spin zero test body is considered. The Zorn-Weyl algebra associated to this generalized formalism has elements belonging to the full octonion algebra [pt
On the ultrarelativistic limit of general relativity
International Nuclear Information System (INIS)
Dautcourt, G.
1998-01-01
As is well-known, Newton's gravitational theory can be formulated as a four-dimensional space-time theory and follows as singular limit from Einstein's theory, if the velocity of light tends to the infinity. Here 'singular' stands for the fact, that the limiting geometrical structure differs from a regular Riemannian space-time. Geometrically, the transition Einstein → Newton can be viewed as an 'opening' of the light cones. This picture suggests that there might be other singular limits of Einstein's theory: Let all light cones shrink and ultimately become part of a congruence of singular world lines. The limiting structure may be considered as a null hypersurface embedded in a five-dimensional spacetime. While the velocity of light tends to zero here, all other velocities tend to the velocity of light. Thus one may speak of an ultrarelativistic limit of General Relativity. The resulting theory is as simple as Newton's gravitational theory, with the basic difference, that Newton's elliptic differential equation is replaced by essentially ordinary differential equations, with derivatives tangent to the generators of the singular congruence. The Galilei group is replaced by the Carroll group introduced by Levy-Leblond. We suggest to study near ultrarelativistic situations with a perturbational approach starting from the singular structure, similar to post-Newtonian expansions in the c → ∞ case. (author)
Isotropic stars in general relativity
International Nuclear Information System (INIS)
Mak, M.K.; Harko, T.
2013-01-01
We present a general solution of the Einstein gravitational field equations for the static spherically symmetric gravitational interior space-time of an isotropic fluid sphere. The solution is obtained by transforming the pressure isotropy condition, a second order ordinary differential equation, into a Riccati type first order differential equation, and using a general integrability condition for the Riccati equation. This allows us to obtain an exact non-singular solution of the interior field equations for a fluid sphere, expressed in the form of infinite power series. The physical features of the solution are studied in detail numerically by cutting the infinite series expansions, and restricting our numerical analysis by taking into account only n=21 terms in the power series representations of the relevant astrophysical parameters. In the present model all physical quantities (density, pressure, speed of sound etc.) are finite at the center of the sphere. The physical behavior of the solution essentially depends on the equation of state of the dense matter at the center of the star. The stability properties of the model are also analyzed in detail for a number of central equations of state, and it is shown that it is stable with respect to the radial adiabatic perturbations. The astrophysical analysis indicates that this solution can be used as a realistic model for static general relativistic high density objects, like neutron stars. (orig.)
Stochastic quantization of general relativity
International Nuclear Information System (INIS)
Rumpf, H.
1986-01-01
Following an elementary exposition of the basic mathematical concepts used in the theory of stochastic relaxation processes the stochastic quantization method of Parisi and Wu is briefly reviewed. The method is applied to Einstein's theory of gravitation using a formalism that is manifestly covariant with respect to field redefinitions. This requires the adoption of Ito's calculus and the introduction of a metric in field configuration space, for which there is a unique candidate. Due to the indefiniteness of the Euclidean Einstein-Hilbert action stochastic quantization is generalized to the pseudo-Riemannian case. It is formally shown to imply the DeWitt path integral measure. Finally a new type of perturbation theory is developed. (Author)
A logic road from special relativity to general relativity
Andréka, Hajnal; Madarász, Judit X.; Németi, István; Székely, Gergely
2010-01-01
We present a streamlined axiom system of special relativity in first-order logic. From this axiom system we "derive" an axiom system of general relativity in two natural steps. We will also see how the axioms of special relativity transform into those of general relativity. This way we hope to make general relativity more accessible for the non-specialist.
Conformal methods in general relativity
Valiente Kroon, Juan A
2016-01-01
This book offers a systematic exposition of conformal methods and how they can be used to study the global properties of solutions to the equations of Einstein's theory of gravity. It shows that combining these ideas with differential geometry can elucidate the existence and stability of the basic solutions of the theory. Introducing the differential geometric, spinorial and PDE background required to gain a deep understanding of conformal methods, this text provides an accessible account of key results in mathematical relativity over the last thirty years, including the stability of de Sitter and Minkowski spacetimes. For graduate students and researchers, this self-contained account includes useful visual models to help the reader grasp abstract concepts and a list of further reading, making this the perfect reference companion on the topic.
Pulsar timing and general relativity
Backer, D. C.; Hellings, R. W.
1986-01-01
Techniques are described for accounting for relativistic effects in the analysis of pulsar signals. Design features of instrumentation used to achieve millisecond accuracy in the signal measurements are discussed. The accuracy of the data permits modeling the pulsar physical characteristics from the natural glitches in the emissions. Relativistic corrections are defined for adjusting for differences between the pulsar motion in its spacetime coordinate system relative to the terrestrial coordinate system, the earth's motion, and the gravitational potentials of solar system bodies. Modifications of the model to allow for a binary pulsar system are outlined, including treatment of the system as a point mass. Finally, a quadrupole model is presented for gravitational radiation and techniques are defined for using pulsars in the search for gravitational waves.
Flux formulation of DFT on group manifolds and generalized Scherk-Schwarz compactifications
Energy Technology Data Exchange (ETDEWEB)
Bosque, Pascal du [Max-Planck-Institut für Physik,Föhringer Ring 6, 80805 München (Germany); Arnold-Sommerfeld-Center für Theoretische Physik,Fakultät für Physik, Ludwig-Maximilians-Universität München,Theresienstraße 37, 80333 München (Germany); Hassler, Falk [University of North Carolina, Department of Physics and Astronomy,Phillips Hall, CB #3255, 120 E. Cameron Ave., Chapel Hill, NC 27599-3255 (United States); City University of New York, The Graduate Center,365 Fifth Avenue, New York, NY 10016 (United States); Columbia University, Department of Physics,Pupin Hall, 550 West 120th St., New York, NY 10027 (United States); Lüst, Dieter [Max-Planck-Institut für Physik,Föhringer Ring 6, 80805 München (Germany); Arnold-Sommerfeld-Center für Theoretische Physik,Fakultät für Physik, Ludwig-Maximilians-Universität München,Theresienstraße 37, 80333 München (Germany)
2016-02-04
A flux formulation of Double Field Theory on group manifold is derived and applied to study generalized Scherk-Schwarz compactifications, which give rise to a bosonic subsector of half-maximal, electrically gauged supergravities. In contrast to the flux formulation of original DFT, the covariant fluxes split into a fluctuation and a background part. The latter is connected to a 2D-dimensional, pseudo Riemannian manifold, which is isomorphic to a Lie group embedded into O(D,D). All fields and parameters of generalized diffeomorphisms are supported on this manifold, whose metric is spanned by the background vielbein E{sub A}{sup I}∈ GL(2D). This vielbein takes the role of the twist in conventional generalized Scherk-Schwarz compactifications. By doing so, it solves the long standing problem of constructing an appropriate twist for each solution of the embedding tensor. Using the geometric structure, absent in original DFT, E{sub A}{sup I} is identified with the left invariant Maurer-Cartan form on the group manifold, in the same way as it is done in geometric Scherk-Schwarz reductions. We show in detail how the Maurer-Cartan form for semisimple and solvable Lie groups is constructed starting from the Lie algebra. For all compact embeddings in O(3,3), we calculate E{sub A}{sup I}.
The use of generalized functions and distributions in general relativity
International Nuclear Information System (INIS)
Steinbauer, R; Vickers, J A
2006-01-01
We review the extent to which one can use classical distribution theory in describing solutions of Einstein's equations. We show that there are a number of physically interesting cases which cannot be treated using distribution theory but require a more general concept. We describe a mathematical theory of nonlinear generalized functions based on Colombeau algebras and show how this may be applied in general relativity. We end by discussing the concept of singularity in general relativity and show that certain solutions with weak singularities may be regarded as distributional solutions of Einstein's equations. (topical review)
Canonical quantization of general relativity in discrete space-times.
Gambini, Rodolfo; Pullin, Jorge
2003-01-17
It has long been recognized that lattice gauge theory formulations, when applied to general relativity, conflict with the invariance of the theory under diffeomorphisms. We analyze discrete lattice general relativity and develop a canonical formalism that allows one to treat constrained theories in Lorentzian signature space-times. The presence of the lattice introduces a "dynamical gauge" fixing that makes the quantization of the theories conceptually clear, albeit computationally involved. The problem of a consistent algebra of constraints is automatically solved in our approach. The approach works successfully in other field theories as well, including topological theories. A simple cosmological application exhibits quantum elimination of the singularity at the big bang.
General relativity and mathematics; Relatividad General y Matematicas
Energy Technology Data Exchange (ETDEWEB)
Mars, M.
2015-07-01
General relativity is more than a theory of gravity, since any physical process occupies space and lasts for a time, forcing to reconcile that physical theory that describes what the dynamic nature of space-time itself. (Author)
GENERALIZATION, FORMULATION AND HEAT CONTENTS OF SIMULATED MSW WITH HIGH MOISTURE CONTENT
Directory of Open Access Journals (Sweden)
A. JOHARI
2012-12-01
Full Text Available This paper presents a generalization technique for the formulation of simulated municipal solid waste. This technique is used for the elimination of the inconsistency in the municipal solid waste (MSW characteristics due to its heterogeneous nature. The compositions of simulated municipal solid waste were formulated from four major municipal waste streams components in Malaysia namely paper, plastic, food and yard waste. The technique produced four simplified waste generalization categories with composition of paper (19%, plastic (25%, food (27% and green waste (29% respectively. Comparative study was conducted for proximate analysis for the determination of volatile matter, fixed carbon and ash content. Ultimate analysis was performed for carbon and hydrogen content. The heat content for simulated and actual municipal solid waste showed good agreement. The moisture content of the simulated municipal solid waste and actual municipal solid waste were established at 52.34% and 61.71% respectively. Overall results were considered to be representative of the actual compositions of municipal solid waste in Malaysia.
Extent of the Immirzi ambiguity in quantum general relativity
International Nuclear Information System (INIS)
Marugan, Guillermo A Mena
2002-01-01
The Ashtekar-Barbero formulation of general relativity admits a one-parameter family of canonical transformations that preserves the expressions of the Gauss and diffeomorphism constraints. The loop quantization of the connection formalism based on each of these canonical sets leads to different predictions. This phenomenon is called the Immirzi ambiguity. It has been recently argued that this ambiguity could be generalized to the extent of a spatially dependent function instead of a parameter. This would ruin the predictability of loop quantum gravity. We prove that such expectations are not realized, so that the Immirzi ambiguity introduces exclusively a freedom in the choice of a real number. (letter to the editor)
Dingreville, Rémi; Hallil, Abdelmalek; Berbenni, Stéphane
2014-12-01
The equilibrium of coherent and incoherent mismatched interfaces is reformulated in the context of continuum mechanics based on the Gibbs dividing surface concept. Two surface stresses are introduced: a coherent surface stress and an incoherent surface stress, as well as a transverse excess strain. The coherent surface stress and the transverse excess strain represent the thermodynamic driving forces of stretching the interface while the incoherent surface stress represents the driving force of stretching one crystal while holding the other fixed and thereby altering the structure of the interface. These three quantities fully characterize the elastic behavior of coherent and incoherent interfaces as a function of the in-plane strain, the transverse stress and the mismatch strain. The isotropic case is developed in detail and particular attention is paid to the case of interfacial thermo-elasticity. This exercise provides an insight on the physical significance of the interfacial elastic constants introduced in the formulation and illustrates the obvious coupling between the interface structure and its associated thermodynamics quantities. Finally, an example based on atomistic simulations of Cu/Cu2O interfaces is given to demonstrate the relevance of the generalized interfacial formulation and to emphasize the dependence of the interfacial thermodynamic quantities on the incoherency strain with an actual material system.
General Relativity in (1 + 1) Dimensions
Boozer, A. D.
2008-01-01
We describe a theory of gravity in (1 + 1) dimensions that can be thought of as a toy model of general relativity. The theory should be a useful pedagogical tool, because it is mathematically much simpler than general relativity but shares much of the same conceptual structure; in particular, it gives a simple illustration of how gravity arises…
Measuring brain atrophy with a generalized formulation of the boundary shift integral☆
Prados, Ferran; Cardoso, Manuel Jorge; Leung, Kelvin K.; Cash, David M.; Modat, Marc; Fox, Nick C.; Wheeler-Kingshott, Claudia A.M.; Ourselin, Sebastien
2015-01-01
Brain atrophy measured using structural magnetic resonance imaging (MRI) has been widely used as an imaging biomarker for disease diagnosis and tracking of pathologic progression in neurodegenerative diseases. In this work, we present a generalized and extended formulation of the boundary shift integral (gBSI) using probabilistic segmentations to estimate anatomic changes between 2 time points. This method adaptively estimates a non-binary exclusive OR region of interest from probabilistic brain segmentations of the baseline and repeat scans to better localize and capture the brain atrophy. We evaluate the proposed method by comparing the sample size requirements for a hypothetical clinical trial of Alzheimer's disease to that needed for the current implementation of BSI as well as a fuzzy implementation of BSI. The gBSI method results in a modest but reduced sample size, providing increased sensitivity to disease changes through the use of the probabilistic exclusive OR region. PMID:25264346
The formulations of the AMS/EPA Regulatory Model Improvement Committee's applied air dispersion model (AERMOD) as related to the characterization of the planetary boundary layer are described. This is the first in a series of three articles. Part II describes the formulation of...
The Confrontation between General Relativity and Experiment
Directory of Open Access Journals (Sweden)
Will Clifford
2001-01-01
Full Text Available The status of experimental tests of general relativity and of theoretical frameworks for analysing them are reviewed. Einstein's equivalence principle (EEP is well supported by experiments such as the Eötvös experiment, tests of special relativity, and the gravitational redshift experiment. Future tests of EEP and of the inverse square law will search for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected in an amount that agrees with general relativity to half a percent using the Hulse-Taylor binary pulsar, and new binary pulsar systems may yield further improvements.When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.
Particle field in bimetric general relativity
International Nuclear Information System (INIS)
Falik, D.; Rosen, N.
1980-01-01
The field equations of the bimetric general relativity theory proposed recently by one of the authors (N. Rosen) are put into a static form. The equations are solved near the Schwarzschild sphere, and it is found that the field differs from that of the Einstein general relativity theory: instead of a black hole, one has an impenetrable sphere. For larger distances the field is found to agree with that of ordinary general relativity, so that solar system observations cannot distinguish between the two theories. For very large distances one gets a cosmic contribution to the field which may affect the dynamics of clusters of galaxies
Compact objects in bimetric general relativity
International Nuclear Information System (INIS)
Harpaz, A.; Rosen, N.
1985-01-01
The field equations of the bimetric general relativity theory proposed by one of the authors (N. Rosen), in the static form, are solved in order to investigate the structure of a star. It is found that for an ordinary star the bimetric theory gives the same results as the Einstein general relativity theory. However, for a collapsed star the two theories give different results. In the bimetric theory a configuration in hydrostatic equilibrium exists for a collapsed star filling its Schwarzschild sphere. In general relativity no equilibrium configuration exists in this region, and the star shrinks to a point singularity to form a black hole
Indefinite-metric quantum field theory of general relativity
International Nuclear Information System (INIS)
Nakanishi, Noboru
1978-01-01
Quantum field theory of Einstein's general relativity is formulated in the indefinitemetric Hilbert space in such a way that asymptotic fields are manifestly Lorentz covariant and the physical S-matrix is unitary. The general coordinate transformation is transcribed into a q-number transformation, called the BRS transformation. Its abstract definition is presented on the basis of the BRS transformation for the Yang-Mills theory. The BRS transformation for general relativity is then explicitly constructed. The gauge-fixing Lagrangian density and the Faddeev-Popov one are introduced in such a way that their sum behaves like a scalar density under the BRS transformation. One can then proceed in the same way as in the Kugo-Ojima formalism of the Yang-Mills theory to establish the unitarity of the physical S-matrix. (author)
O(3)-invariant tunneling in general relativity
International Nuclear Information System (INIS)
Berezin, V.A.; Tkachev, I.I.; Kuzmin, V.A.; AN SSSR, Moscow. Inst. Yadernykh Issledovanij)
1987-12-01
We derived a general formula for the action for any O(3)-invariant tunneling processes in false vacuum decay in general relativity. The general classification of the bubble Euclidean trajectories is elaborated and explicit expressions for bounces for some processes like the vacuum creation of a double bubble, in particular in the vicinity of a black hole; the subbarrier creation of the Einstein-Rosen bridge, creation from nothing of two Minkowski worlds connected by a shell etc., are given. (orig.)
Astrometric tests of General Relativity in the Solar system
International Nuclear Information System (INIS)
Gai, M; Vecchiato, A; Riva, A; Lattanzi, M G; Sozzetti, A; Crosta, M T; Busonero, D
2014-01-01
Micro-arcsec astronomy is able to verify the predictions of theoretical models of gravitation at a level adequate to constraint relevant parameters and select among different formulations. In particular, this concerns the weak field limit applicable to the Sun neighborhood, where competing models can be expressed in a common framework as the Parametrised Post-Newtonian and Parametrised Post-Post-Newtonian formulations. The mission Gaia is going to provide an unprecedented determination of the γ PPN parameter at the 10 −6 level. Other recently proposed concepts, as GAME, may improve the precision on γ by one or two orders of magnitude and provide constraints on other crucial phenomenological aspects. We review the key concepts of astrometric tests of General Relativity and discuss a possible development scenario
The Ritz - Sublaminate Generalized Unified Formulation approach for piezoelectric composite plates
D'Ottavio, Michele; Dozio, Lorenzo; Vescovini, Riccardo; Polit, Olivier
2018-01-01
This paper extends to composite plates including piezoelectric plies the variable kinematics plate modeling approach called Sublaminate Generalized Unified Formulation (SGUF). Two-dimensional plate equations are obtained upon defining a priori the through-thickness distribution of the displacement field and electric potential. According to SGUF, independent approximations can be adopted for the four components of these generalized displacements: an Equivalent Single Layer (ESL) or Layer-Wise (LW) description over an arbitrary group of plies constituting the composite plate (the sublaminate) and the polynomial order employed in each sublaminate. The solution of the two-dimensional equations is sought in weak form by means of a Ritz method. In this work, boundary functions are used in conjunction with the domain approximation expressed by an orthogonal basis spanned by Legendre polynomials. The proposed computational tool is capable to represent electroded surfaces with equipotentiality conditions. Free-vibration problems as well as static problems involving actuator and sensor configurations are addressed. Two case studies are presented, which demonstrate the high accuracy of the proposed Ritz-SGUF approach. A model assessment is proposed for showcasing to which extent the SGUF approach allows a reduction of the number of unknowns with a controlled impact on the accuracy of the result.
Energy Technology Data Exchange (ETDEWEB)
Salloum, Maher; Knio, Omar M. [Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218-2686 (United States)
2010-06-15
A transient multidimensional reduced model is constructed for the simulation of reaction fronts in Ni/Al multilayers. The formulation is based on the generalization of earlier methodologies developed for quasi-1D axial and normal propagation, specifically by adapting the reduced formalism for atomic mixing and heat release. This approach enables us to focus on resolving the thermal front structure, whose evolution is governed by thermal diffusion and heat release. A mixed integration scheme is used for this purpose, combining an extended-stability, Runge-Kutta-Chebychev (RKC) integration of the diffusion term with exact treatment of the chemical source term. Thus, a detailed description of atomic mixing within individual layers is avoided, which enables transient modeling of the reduced equations of motion in multiple dimensions. Two-dimensional simulations are first conducted of front propagation in composites combining two bilayer periods. Results are compared with the experimental measurements of Knepper et al., which reveal that the reaction velocity can depend significantly on layering frequency. The comparison indicates that, using a concentration-dependent conductivity model, the transient 2D computations can reasonably reproduce the experimental behavior. Additional tests are performed based on 3D computations of surface initiated reactions. Comparison of computed predictions with laser ignition measurements indicates that the computations provide reasonable estimates of ignition thresholds. A detailed discussion is finally provided of potential generalizations and associated hurdles. (author)
Axisymmetric solution with charge in general relativity
International Nuclear Information System (INIS)
Arutyunyan, G.G.; Papoyan, V.V.
1989-01-01
The possibility of generating solutions to the equations of general relativity from known solutions of the generalized theory of gravitation and vice versa is proved. An electrovac solution to Einstein's equations that describes a static axisymmetric gravitational field is found. 14 refs
Einstein and General Relativity: Historical Perspectives.
Chandrasekhar, S.
1979-01-01
This paper presented in the 1978 Oppenheimer Memorial Lecture at Los Alamos Scientific Laboratories on August 17, 1978, discusses Einstein's contributions to physics, in particular, his discovery of the general theory of relativity. (HM)
Quantum theory and Einstein's general relativity
International Nuclear Information System (INIS)
Borzeszkowski, H.H.v.; Treder, H.J.
1984-01-01
The paper concerns Einstein's general relativity, wave mechanics and the quantization of Einstein's gravitation equations. The principle of equivalence and its association with both wave mechanics and quantum gravity, is discussed. (U.K.)
Black hole dynamics in general relativity
Indian Academy of Sciences (India)
Abstract. Basic features of dynamical black holes in full, non-linear general relativity are summarized in a pedagogical fashion. Qualitative properties of the evolution of various horizons follow directly from the celebrated Raychaudhuri equation.
Einstein and general relativity: historical perspectives
International Nuclear Information System (INIS)
Chandrasekhar, S.
1978-01-01
The place of Einstein in 20th-century physics is discussed. The basic ideas that led Einstein to his theory of gravitation by the sheer power of speculative thought are described in the most general terms. The prediction of the bending of starlight by the Sun and the eclipse expedition of 1919 are recounted. The author feels that ''the general theory of relativity is incredibly rich in its content;...one finds a glittering face at almost every turn.'' The prediction of black holes by general relativity is noted
Energy and Uncertainty in General Relativity
Cooperstock, F. I.; Dupre, M. J.
2018-03-01
The issue of energy and its potential localizability in general relativity has challenged physicists for more than a century. Many non-invariant measures were proposed over the years but an invariant measure was never found. We discovered the invariant localized energy measure by expanding the domain of investigation from space to spacetime. We note from relativity that the finiteness of the velocity of propagation of interactions necessarily induces indefiniteness in measurements. This is because the elements of actual physical systems being measured as well as their detectors are characterized by entire four-velocity fields, which necessarily leads to information from a measured system being processed by the detector in a spread of time. General relativity adds additional indefiniteness because of the variation in proper time between elements. The uncertainty is encapsulated in a generalized uncertainty principle, in parallel with that of Heisenberg, which incorporates the localized contribution of gravity to energy. This naturally leads to a generalized uncertainty principle for momentum as well. These generalized forms and the gravitational contribution to localized energy would be expected to be of particular importance in the regimes of ultra-strong gravitational fields. We contrast our invariant spacetime energy measure with the standard 3-space energy measure which is familiar from special relativity, appreciating why general relativity demands a measure in spacetime as opposed to 3-space. We illustrate the misconceptions by certain authors of our approach.
Hamiltonian Dynamics and Positive Energy in General Relativity
Energy Technology Data Exchange (ETDEWEB)
Deser, S. [Physics Department, Brandeis University, Waltham, MA (United States)
1969-07-15
A review is first given of the Hamiltonian formulation of general relativity; the gravitational field is a self-interacting massless spin-two system within the framework of ordinary Lorentz covariant field theory. The recently solved problem of positive-definiteness of the field energy is then discussed. The latter, a conserved functional of the dynamical variables, is shown to have only one extremum, a local minimum, which is the vacuum state (flat space). This implies positive energy for the field, with the vacuum as ground-state. Similar results hold when minimally coupled matter is present. (author)
Supersymmetry, General Relativity and Unity of Nature
Shima, Kazunari; Tsuda, Motomu
2008-01-01
The basic idea and some physical implications of nonlinear supersymmetric general relativity (NLSUSY GR) are presented. NLSUSY GR may give new insights into the origin of mass and the mysterious relations between the cosmology and the low energy particle physics, e.g. the spontaneous SUSY breaking scale, the cosmological constant, the (dark) energy density of the universe and the neutrino mass.
Teaching General Relativity to the Layperson
Egdall, Mark
2009-01-01
This paper describes a lay course on general relativity (GR) given at the Osher Lifelong Learning Institute at Florida International University. It is presented in six hour-and-a-half weekly sessions. Other courses offered by the author include special relativity (which precedes the course described here), quantum theory, and cosmology. Students…
Black hole based tests of general relativity
International Nuclear Information System (INIS)
Yagi, Kent; Stein, Leo C
2016-01-01
General relativity has passed all solar system experiments and neutron star based tests, such as binary pulsar observations, with flying colors. A more exotic arena for testing general relativity is in systems that contain one or more black holes. Black holes are the most compact objects in the Universe, providing probes of the strongest-possible gravitational fields. We are motivated to study strong-field gravity since many theories give large deviations from general relativity only at large field strengths, while recovering the weak-field behavior. In this article, we review how one can probe general relativity and various alternative theories of gravity by using electromagnetic waves from a black hole with an accretion disk, and gravitational waves from black hole binaries. We first review model-independent ways of testing gravity with electromagnetic/gravitational waves from a black hole system. We then focus on selected examples of theories that extend general relativity in rather simple ways. Some important characteristics of general relativity include (but are not limited to) (i) only tensor gravitational degrees of freedom, (ii) the graviton is massless, (iii) no quadratic or higher curvatures in the action, and (iv) the theory is four-dimensional. Altering a characteristic leads to a different extension of general relativity: (i) scalar–tensor theories, (ii) massive gravity theories, (iii) quadratic gravity, and (iv) theories with large extra dimensions. Within each theory, we describe black hole solutions, their properties, and current and projected constraints on each theory using black hole based tests of gravity. We close this review by listing some of the open problems in model-independent tests and within each specific theory. (paper)
General very special relativity in Finsler cosmology
International Nuclear Information System (INIS)
Kouretsis, A. P.; Stathakopoulos, M.; Stavrinos, P. C.
2009-01-01
General very special relativity (GVSR) is the curved space-time of very special relativity (VSR) proposed by Cohen and Glashow. The geometry of general very special relativity possesses a line element of Finsler geometry introduced by Bogoslovsky. We calculate the Einstein field equations and derive a modified Friedmann-Robertson-Walker cosmology for an osculating Riemannian space. The Friedmann equation of motion leads to an explanation of the cosmological acceleration in terms of an alternative non-Lorentz invariant theory. A first order approach for a primordial-spurionic vector field introduced into the metric gives back an estimation of the energy evolution and inflation.
The Confrontation between General Relativity and Experiment.
Will, Clifford M
2014-01-01
The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein's equivalence principle (EEP) is well supported by experiments such as the Eötvös experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.
Measuring brain atrophy with a generalized formulation of the boundary shift integral.
Prados, Ferran; Cardoso, Manuel Jorge; Leung, Kelvin K; Cash, David M; Modat, Marc; Fox, Nick C; Wheeler-Kingshott, Claudia A M; Ourselin, Sebastien
2015-01-01
Brain atrophy measured using structural magnetic resonance imaging (MRI) has been widely used as an imaging biomarker for disease diagnosis and tracking of pathologic progression in neurodegenerative diseases. In this work, we present a generalized and extended formulation of the boundary shift integral (gBSI) using probabilistic segmentations to estimate anatomic changes between 2 time points. This method adaptively estimates a non-binary exclusive OR region of interest from probabilistic brain segmentations of the baseline and repeat scans to better localize and capture the brain atrophy. We evaluate the proposed method by comparing the sample size requirements for a hypothetical clinical trial of Alzheimer's disease to that needed for the current implementation of BSI as well as a fuzzy implementation of BSI. The gBSI method results in a modest but reduced sample size, providing increased sensitivity to disease changes through the use of the probabilistic exclusive OR region. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
A generalized formulation for noise-based seismic velocity change measurements
Gómez-García, C.; Brenguier, F.; Boué, P.; Shapiro, N.; Droznin, D.; Droznina, S.; Senyukov, S.; Gordeev, E.
2017-12-01
The observation of continuous seismic velocity changes is a powerful tool for detecting seasonal variations in crustal structure, volcanic unrest, co- and post-seismic evolution of stress in fault areas or the effects of fluid injection. The standard approach for measuring such velocity changes relies on comparison of travel times in the coda of a set of seismic signals, usually noise-based cross-correlations retrieved at different dates, and a reference trace, usually a averaged function over dates. A good stability in both space and time of the noise sources is then the main assumption for reliable measurements. Unfortunately, these conditions are often not fulfilled, as it happens when ambient-noise sources are non-stationary, such as the emissions of low-frequency volcanic tremors.We propose a generalized formulation for retrieving continuous time series of noise-based seismic velocity changes without any arbitrary reference cross-correlation function. We set up a general framework for future applications of this technique performing synthetic tests. In particular, we study the reliability of the retrieved velocity changes in case of seasonal-type trends, transient effects (similar to those produced as a result of an earthquake or a volcanic eruption) and sudden velocity drops and recoveries as the effects of transient local source emissions. Finally, we apply this approach to a real dataset of noise cross-correlations. We choose the Klyuchevskoy volcanic group (Kamchatka) as a case study where the recorded wavefield is hampered by loss of data and dominated by strongly localized volcanic tremor sources. Despite the mentioned wavefield contaminations, we retrieve clear seismic velocity drops associated with the eruptions of the Klyuchevskoy an the Tolbachik volcanoes in 2010 and 2012, respectively.
On generalization uniaxial stress-strain relation
International Nuclear Information System (INIS)
Sahay, C.; Dubey, R.N.
1980-01-01
Different forms of constitutive relations have been advanced for elastic, plastic and elastic-plastic behaviour of materials. It is shown that the various forms of the stress-strain relationship are specialized forms of generalization of a single stress-strain relation. For example, it is shown how the laws of elastic deformation, and the incremental and total deformation relationship for plastic behaviour are derivable from the Ramberg-Osgood relation. (orig.)
Generalized transformations and coordinates for static spherically symmetric general relativity
Hill, James M.; O'Leary, Joseph
2018-04-01
We examine a static, spherically symmetric solution of the empty space field equations of general relativity with a non-orthogonal line element which gives rise to an opportunity that does not occur in the standard derivations of the Schwarzschild solution. In these derivations, convenient coordinate transformations and dynamical assumptions inevitably lead to the Schwarzschild solution. By relaxing these conditions, a new solution possibility arises and the resulting formalism embraces the Schwarzschild solution as a special case. The new solution avoids the coordinate singularity associated with the Schwarzschild solution and is achieved by obtaining a more suitable coordinate chart. The solution embodies two arbitrary constants, one of which can be identified as the Newtonian gravitational potential using the weak field limit. The additional arbitrary constant gives rise to a situation that allows for generalizations of the Eddington-Finkelstein transformation and the Kruskal-Szekeres coordinates.
Generalized transformations and coordinates for static spherically symmetric general relativity.
Hill, James M; O'Leary, Joseph
2018-04-01
We examine a static, spherically symmetric solution of the empty space field equations of general relativity with a non-orthogonal line element which gives rise to an opportunity that does not occur in the standard derivations of the Schwarzschild solution. In these derivations, convenient coordinate transformations and dynamical assumptions inevitably lead to the Schwarzschild solution. By relaxing these conditions, a new solution possibility arises and the resulting formalism embraces the Schwarzschild solution as a special case. The new solution avoids the coordinate singularity associated with the Schwarzschild solution and is achieved by obtaining a more suitable coordinate chart. The solution embodies two arbitrary constants, one of which can be identified as the Newtonian gravitational potential using the weak field limit. The additional arbitrary constant gives rise to a situation that allows for generalizations of the Eddington-Finkelstein transformation and the Kruskal-Szekeres coordinates.
Generalized Disjunctions in (Infinitary) Structural Consequence Relations
Czech Academy of Sciences Publication Activity Database
Cintula, Petr; Noguera, C.
2012-01-01
Roč. 18, č. 3 (2012), s. 442-443 ISSN 1079-8986. [Logic Colloquium 2011. 11.07.2011-16.07.2011, Barcelona] R&D Projects: GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10300504 Keywords : Abstract Algebraic Logic * Generalized disjunction * Proof by cases properties * Consequence relations Subject RIV: BA - General Mathematics http://www.math.ucla.edu/~asl/bsl/1803- toc .htm
Einstein and the history of general relativity
International Nuclear Information System (INIS)
Howard, D.; Stachel, J.
1989-01-01
This book is a collection of essays by the authors and other people that deal with scientific opinions that led Einstein and his contemporaries to their views of general relativity. Some of the essays explore Einstein's passage from the special theory through a sequence of gravitational theories to the discovery of the field equations of the grand theory in November 1915. Two other essays discuss Einstein's public and private exchanges with Max Abraham and Tullio Levi-Civita in 1913 and 1914. A sympathetic picture of H.A. Lorentz's reaction to the general theory of relativity is included, and a careful and insightful essay on the early understanding of the Schwarzschild-Droste solution to the field equations of general relativity is presented. One paper presents a discussion on the state of the enterprise of general relativity between 1925 and 1928, and a short essay details the history of steps toward quantum gravitational through canonical quantization. A discussion of the history of derivations of the geodesic equation of motion from the field equation and conservation laws of the general theory is presented. The early history of geometrical unified field theories is included
International Nuclear Information System (INIS)
Zhou Sumin; Das, Shiva; Wang Zhiheng; Marks, Lawrence B.
2004-01-01
The generalized equivalent uniform dose (GEUD) model uses a power-law formalism, where the outcome is related to the dose via a power law. We herein investigate the mathematical compatibility between this GEUD model and the Poisson statistics based tumor control probability (TCP) model. The GEUD and TCP formulations are combined and subjected to a compatibility constraint equation. This compatibility constraint equates tumor control probability from the original heterogeneous target dose distribution to that from the homogeneous dose from the GEUD formalism. It is shown that this constraint equation possesses a unique, analytical closed-form solution which relates radiation dose to the tumor cell survival fraction. It is further demonstrated that, when there is no positive threshold or finite critical dose in the tumor response to radiation, this relationship is not bounded within the realistic cell survival limits of 0%-100%. Thus, the GEUD and TCP formalisms are, in general, mathematically inconsistent. However, when a threshold dose or finite critical dose exists in the tumor response to radiation, there is a unique mathematical solution for the tumor cell survival fraction that allows the GEUD and TCP formalisms to coexist, provided that all portions of the tumor are confined within certain specific dose ranges
Generalized Landau-Pollak uncertainty relation
International Nuclear Information System (INIS)
Miyadera, Takayuki; Imai, Hideki
2007-01-01
The Landau-Pollak uncertainty relation treats a pair of rank one projection valued measures and imposes a restriction on their probability distributions. It gives a nontrivial bound for summation of their maximum values. We give a generalization of this bound (weak version of the Landau-Pollak uncertainty relation). Our generalization covers a pair of positive operator valued measures. A nontrivial but slightly weak inequality that can treat an arbitrary number of positive operator valued measures is also presented. A possible application to the problem of separability criterion is also suggested
The Confrontation between General Relativity and Experiment
Directory of Open Access Journals (Sweden)
Will Clifford M.
2006-03-01
Full Text Available The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed. Einstein’s equivalence principle (EEP is well supported by experiments such as the Eötvös experiment, tests of special relativity, and the gravitational redshift experiment. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, and the Nordtvedt effect in lunar motion. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse-Taylor binary pulsar, and other binary pulsar systems have yielded other tests, especially of strong-field effects. When direct observation of gravitational radiation from astrophysical sources begins, new tests of general relativity will be possible.
Relational Coordination in Danish General Practice
DEFF Research Database (Denmark)
Lundstrøm, Sanne Lykke
. The dissertation present the research study and a collection of three research papers prepared during the period from May 2010 to June 2014. Relational coordination and organisational social capital are measures of novel aspects of an organisation's performance. Relational coordination analyse the communication...... and relationship networks through which work is coordinated across functional and organisational boundaries. Previous studies have shown that relational coordination is positively associated with delivery of care for patients with chronic illness. Organisational social capital is used when analysing...... the psychosocial work environment in organisations, and is seen as a powerful resources for improving organisational performance. Relational coordination and organisational social capital may oer new insight and opportunities for general practice to learn. General practice provides cost-efficient, first...
Generating perfect fluid spheres in general relativity
Boonserm, Petarpa; Visser, Matt; Weinfurtner, Silke
2005-06-01
Ever since Karl Schwarzschild’s 1916 discovery of the spacetime geometry describing the interior of a particular idealized general relativistic star—a static spherically symmetric blob of fluid with position-independent density—the general relativity community has continued to devote considerable time and energy to understanding the general-relativistic static perfect fluid sphere. Over the last 90 years a tangle of specific perfect fluid spheres has been discovered, with most of these specific examples seemingly independent from each other. To bring some order to this collection, in this article we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres.
Generating perfect fluid spheres in general relativity
International Nuclear Information System (INIS)
Boonserm, Petarpa; Visser, Matt; Weinfurtner, Silke
2005-01-01
Ever since Karl Schwarzschild's 1916 discovery of the spacetime geometry describing the interior of a particular idealized general relativistic star--a static spherically symmetric blob of fluid with position-independent density--the general relativity community has continued to devote considerable time and energy to understanding the general-relativistic static perfect fluid sphere. Over the last 90 years a tangle of specific perfect fluid spheres has been discovered, with most of these specific examples seemingly independent from each other. To bring some order to this collection, in this article we develop several new transformation theorems that map perfect fluid spheres into perfect fluid spheres. These transformation theorems sometimes lead to unexpected connections between previously known perfect fluid spheres, sometimes lead to new previously unknown perfect fluid spheres, and in general can be used to develop a systematic way of classifying the set of all perfect fluid spheres
Generalization of Gibbs Entropy and Thermodynamic Relation
Park, Jun Chul
2010-01-01
In this paper, we extend Gibbs's approach of quasi-equilibrium thermodynamic processes, and calculate the microscopic expression of entropy for general non-equilibrium thermodynamic processes. Also, we analyze the formal structure of thermodynamic relation in non-equilibrium thermodynamic processes.
Gravity: An Introduction to Einstein's General Relativity
International Nuclear Information System (INIS)
Fabris, Julio C
2004-01-01
General relativity is one of the cornerstones of modern physics. In spite of this, the teaching of general relativity at undergraduate level remains quite marginal. The reasons for this particular situation are quite well known. We can quote, for example, two of them: general relativity requires specific mathematical tools that are somehow outside the mainstream of undergraduate technical development; moreover, this is a branch of physics whose observational and experimental applications have remained rare until recent times, and even though this scenario has changed dramatically in the last few years, the new situation has not yet been absorbed into undergraduate teaching. In this new book, Hartle attempts to address the difficulties that must be faced by anyone who teaches general relativity at undergraduate level. In order to not scare the student with the hard technical preparation needed to obtain the basic equations of general relativity, Einstein's equations, he simply gives up the idea of introducing these equations at the very beginning. Instead, he chooses to present Einstein's equations, with most of the mathematics needed to do them, in the last part of the book. This delicate (and of course dangerous) choice has the advantage of introducing the reader first to the physical aspects of general relativity. This approach can be dangerous because the relevant solutions of the equations necessary to discuss the physical content of general relativity are presented first without a formal derivation. The book is divided into three parts. In the first, covering five chapters of the 24 in the whole book, Newtonian physics and special relativity are reviewed. This review is done in a manner that prepares the reader for the subsequent discussion of general relativity itself. The principle of relativity, the variational principle, the geometrical content of Newtonian theory and the main ideas behind special relativity are all presented. The heart of the book is, in
Summary of classical general relativity workshop
Indian Academy of Sciences (India)
In the classical general relativity workshop, ten lectures were presented on various topics. The topics included aspects of black-hole physics, gravitational collapse and the formation of black holes, specific stellar models like a superdense star, method of extracting solutions by exploiting Noether symmetry, brane world and.
The confrontation between general relativity and experiment
Indian Academy of Sciences (India)
... and tests of gravity at short distance to look for extra spatial dimensions could further constrain alternatives to general relativity. Laser Interferometric Gravitational Wave Observatories on Earth and in space may provide new tests of scalar–tensor gravity and graviton-mass theories via the properties of gravitational waves.
Tests of General Relativity with GW150914
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, M. K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; Boyle, M.; Campanelli, M.; Hemberger, D. A.; Kidder, L. E.; Ossokine, S.; Scheel, M. A.; Szilagyi, B.; Teukolsky, S.; Zlochower, Y.; LIGO Scientific; Virgo Collaborations
2016-06-01
The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 1013 km . In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.
Tests of General Relativity with GW150914.
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Rolland, L; Rollins, J G; Roma, V J; Romano, R; Romanov, G; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sanchez, E J; Sandberg, V; Sandeen, B; Sanders, J R; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Sauter, O; Savage, R L; Sawadsky, A; Schale, P; Schilling, R; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Schönbeck, A; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Serna, G; Setyawati, Y; Sevigny, A; Shaddock, D A; Shah, S; Shahriar, M S; Shaltev, M; Shao, Z; Shapiro, B; Shawhan, P; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sigg, D; Silva, A D; Simakov, D; Singer, A; Singer, L P; Singh, A; Singh, R; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, J R; Smith, N D; Smith, R J E; Son, E J; Sorazu, B; Sorrentino, F; Souradeep, T; Srivastava, A K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Stone, R; Strain, K A; Straniero, N; Stratta, G; Strauss, N A; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sutton, P J; Swinkels, B L; Szczepańczyk, M J; Tacca, M; Talukder, D; Tanner, D B; Tápai, M; Tarabrin, S P; Taracchini, A; Taylor, R; Theeg, T; Thirugnanasambandam, M P; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Tomlinson, C; Tonelli, M; Torres, C V; Torrie, C I; Töyrä, D; Travasso, F; Traylor, G; Trifirò, D; Tringali, M C; Trozzo, L; Tse, M; Turconi, M; Tuyenbayev, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; van Bakel, N; van Beuzekom, M; van den Brand, J F J; Van Den Broeck, C; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Vass, S; Vasúth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Viceré, A; Vinciguerra, S; Vine, D J; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Voss, D; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, X; Wang, Y; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Weßels, P; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Williams, D; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Worden, J; Wright, J L; Wu, G; Yablon, J; Yam, W; Yamamoto, H; Yancey, C C; Yap, M J; Yu, H; Yvert, M; Zadrożny, A; Zangrando, L; Zanolin, M; Zendri, J-P; Zevin, M; Zhang, F; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J; Boyle, M; Campanelli, M; Hemberger, D A; Kidder, L E; Ossokine, S; Scheel, M A; Szilagyi, B; Teukolsky, S; Zlochower, Y
2016-06-03
The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13} km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.
Solitons and action propagation according to general relativity (Part one)
International Nuclear Information System (INIS)
Stavroulakis, N.
1987-01-01
The current exposition of General Relativity involves two contradictory statements: at first it is asserted that every change in the distribution of matter brings about gravitational waves. Then it is asserted that, specifically, no gravitational effect is produced by the pulsations of a spherical source. By analysing the second statement, we conclude that it arises from a vicious circle tied up with mathematical errors which led to the Schwarzschild solution and the theory of black holes. In order to obtain the correct formulation of the problem, we establish rigorously the general form of the θ(4)-invariant space-time metrics on R x R 3 and bring out the principles allowing to associate gravitational effects with oscillating masses [fr
Charged point particles with magnetic moment in general relativity
International Nuclear Information System (INIS)
Amorim, R.; Tiomno, J.
1977-01-01
Halbwachs Lagrangean formalism for the theory of charged point particles with spin (g = 2) is generalized and formulated in General Relativity for particles of arbitrary charge and magnetic moment. Equations are obtained, both corresponding to Frenkel's condition Ssub(μν)Xsup(ν) = 0 and to Nakano's condition Ssub(μν)Psup(ν) = 0. With the later condition the exact equations are highly coupled and non linear. When linearized in the electromagnetic and gravitational fields they coincide with de Groot-Suttorp equations for vanishing gravitational fields and with Dixon-Wald equations in the absence of electromagnetic field. The equations corresponding to Frenkel's condition, when linearized in Ssub(μν), coincide with Papapetrou's and Frenkel's equations in the corresponding limits [pt
General relativity and gravitation a centennial perspective
Berger, Beverly K; Isenberg, James; MacCallum, Malcolm
2015-01-01
Explore spectacular advances in cosmology, relativistic astrophysics, gravitational wave science, mathematics, computational science, and the interface of gravitation and quantum physics with this unique celebration of the centennial of Einstein's discovery of general relativity. Twelve comprehensive and in-depth reviews, written by a team of world-leading international experts, together present an up-to-date overview of key topics at the frontiers of these areas, with particular emphasis on the significant developments of the last three decades. Interconnections with other fields of research are also highlighted, making this an invaluable resource for both new and experienced researchers. Commissioned by the International Society on General Relativity and Gravitation, and including accessible introductions to cutting-edge topics, ample references to original research papers, and informative colour figures, this is a definitive reference for researchers and graduate students in cosmology, relativity, and grav...
General Relativity and John Archibald Wheeler
Ciufolini, Ignazio
2010-01-01
Observational and experimental data pertaining to gravity and cosmology are changing our view of the Universe. General relativity is a fundamental key for the understanding of these observations and its theory is undergoing a continuing enhancement of its intersection with observational and experimental data. These data include direct observations and experiments carried out in our solar system, among which there are direct gravitational wave astronomy, frame dragging and tests of gravitational theories from solar system and spacecraft observations. This book explores John Archibald Wheeler's seminal and enduring contributions in relativistic astrophysics and includes: the General Theory of Relativity and Wheeler's influence; recent developments in the confrontation of relativity with experiments; the theory describing gravitational radiation, and its detection in Earth-based and space-based interferometer detectors as well as in Earth-based bar detectors; the mathematical description of the initial value pro...
Constraints on the structure of naked singularities in classical general relativity
International Nuclear Information System (INIS)
Newman, R.P.A.; Joshi, P.S.
1988-01-01
The known examples of naked singularities in general relativity are, in a certain sense, either gravitationally or causally innocuous. A cosmic censorship theorem is formulated and proved to the effect that this behaviour is characteristic of naked singularities in general spacetimes which do not deviate too far from spherical symmetry. copyright 1988 Academic Press, Inc
The Confrontation between General Relativity and Experiment
Directory of Open Access Journals (Sweden)
Clifford M. Will
2014-06-01
Full Text Available The status of experimental tests of general relativity and of theoretical frameworks for analyzing them is reviewed and updated. Einstein’s equivalence principle (EEP is well supported by experiments such as the Eötvös experiment, tests of local Lorentz invariance and clock experiments. Ongoing tests of EEP and of the inverse square law are searching for new interactions arising from unification or quantum gravity. Tests of general relativity at the post-Newtonian level have reached high precision, including the light deflection, the Shapiro time delay, the perihelion advance of Mercury, the Nordtvedt effect in lunar motion, and frame-dragging. Gravitational wave damping has been detected in an amount that agrees with general relativity to better than half a percent using the Hulse–Taylor binary pulsar, and a growing family of other binary pulsar systems is yielding new tests, especially of strong-field effects. Current and future tests of relativity will center on strong gravity and gravitational waves.
The Production System's Formulation of Relative Clause Structures: Evidence from Polish
McDaniel, Dana; Lech, Dorota
2003-01-01
In this study, we focused on the formulation of relative clauses with preposition and genitive pied-piping. Thirty child (5;9 to 8;4) and 30 adult Polish speakers were given an elicited production task and a grammaticality judgment task. Almost all of the children accepted preposition pied-piping, but only half of them produced it. We suggest that…
Rigter, I M; Schipper, H G; Koopmans, R P; van Kan, H J M; Frijlink, H W; Kager, P A; Guchelaar, H-J
2004-01-01
This study of healthy volunteers shows that the relative bioavailability of albendazole formulations that use arachis oil-polysorbate 80 or hydroxypropyl-beta-cyclodextrin as an excipient was enhanced 4.3- and 9.7-fold compared to the results seen with commercial tablets. Administration of macrogol
Rigter, I. M.; Schipper, H. G.; Koopmans, R. P.; van Kan, H. J. M.; Frijlink, H. W.; Kager, P. A.; Guchelaar, H.-J.
2004-01-01
This study of healthy volunteers shows that the relative bioavailability of albendazole formulations that use arachis oil-polysorbate 80 or hydroxypropyl-beta-cyclodextrin as an excipient was enhanced 4.3- and 9.7-fold compared to the results seen with commercial tablets. Administration of macrogol
BOOK REVIEW: Advanced Mechanics and General Relativity Advanced Mechanics and General Relativity
Louko, Jorma
2011-04-01
Joel Franklin's textbook `Advanced Mechanics and General Relativity' comprises two partially overlapping, partially complementary introductory paths into general relativity at advanced undergraduate level. Path I starts with the Lagrangian and Hamiltonian formulations of Newtonian point particle motion, emphasising the action principle and the connection between symmetries and conservation laws. The concepts are then adapted to point particle motion in Minkowski space, introducing Lorentz transformations as symmetries of the action. There follows a focused development of tensor calculus, parallel transport and curvature, using examples from Newtonian mechanics and special relativity, culminating in the field equations of general relativity. The Schwarzschild solution is analysed, including a detailed discussion of the tidal forces on a radially infalling observer. Basics of gravitational radiation are examined, highlighting the similarities to and differences from electromagnetic radiation. The final topics in Path I are equatorial geodesics in Kerr and the motion of a relativistic string in Minkowski space. Path II starts by introducing scalar field theory on Minkowski space as a limit of point masses connected by springs, emphasising the action principle, conservation laws and the energy-momentum tensor. The action principle for electromagnetism is introduced, and the coupling of electromagnetism to a complex scalar field is developed in a detailed and pedagogical fashion. A free symmetric second-rank tensor field on Minkowski space is introduced, and the action principle of general relativity is recovered from coupling the second-rank tensor to its own energy-momentum tensor. Path II then merges with Path I and, supplanted with judicious early selections from Path I, can proceed to the Schwarzschild solution. The choice of material in each path is logical and focused. A notable example in Path I is that Lorentz transformations in Minkowki space are introduced
Directory of Open Access Journals (Sweden)
Vibha Dwivedi
Full Text Available Ayurveda represents the traditional medicine system of India. Since mechanistic details of therapy in terms of current biology are not available in Ayurvedic literature, modern scientific studies are necessary to understand its major concepts and procedures. It is necessary to examine effects of the whole Ayurvedic formulations rather than their "active" components as is done in most current studies.We tested two different categories of formulations, a Rasayana (Amalaki Rasayana or AR, an herbal derivative and a Bhasma (Rasa-Sindoor or RS, an organo-metallic derivative of mercury, for effects on longevity, development, fecundity, stress-tolerance, and heterogeneous nuclear ribonucleoprotein (hnRNP levels of Drosophila melanogaster using at least 200 larvae or flies for each assay.A 0.5% (weight/volume supplement of AR or RS affected life-history and other physiological traits in distinct ways. While the size of salivary glands, hnRNP levels in larval tissues, and thermotolerance of larvae/adult flies improved significantly following feeding either of the two formulations, the median life span and starvation resistance improved only with AR. Feeding on AR or RS supplemented food improved fecundity differently. Feeding of larvae and adults with AR increased the fecundity while the same with RS had opposite effect. On the contrary, feeding larvae on normal food and adults on AR supplement had no effect on fecundity but a comparable regime of feeding on RS-supplemented food improved fecundity. RS feeding did not cause heavy metal toxicity.The present study with two Ayurvedic formulations reveals formulation-specific effects on several parameters of the fly's life, which seem to generally agree with their recommended human usages in Ayurvedic practices. Thus, Drosophila, with its very rich genetic tools and well-worked-out developmental pathways promises to be a very good model for examining the cellular and molecular bases of the effects of
A general real-time formulation for multi-rate mass transfer problems
Directory of Open Access Journals (Sweden)
O. Silva
2009-08-01
Full Text Available Many flow and transport phenomena, ranging from delayed storage in pumping tests to tailing in river or aquifer tracer breakthrough curves or slow kinetics in reactive transport, display non-equilibrium (NE behavior. These phenomena are usually modeled by non-local in time formulations, such as multi-porosity, multiple processes non equilibrium, continuous time random walk, memory functions, integro-differential equations, fractional derivatives or multi-rate mass transfer (MRMT, among others. We present a MRMT formulation that can be used to represent all these models of non equilibrium. The formulation can be extended to non-linear phenomena. Here, we develop an algorithm for linear mass transfer, which is accurate, computationally inexpensive and easy to implement in existing groundwater or river flow and transport codes. We illustrate this approach by application to published data involving NE groundwater flow and solute transport in rivers and aquifers.
General relativity with applications to astrophysics
Straumann, Norbert
2004-01-01
This text provides a comprehensive and timely introduction to general relativity The foundations of the theory in Part I are thoroughly developed together with the required mathematical background from differential geometry in Part III The six chapters in Part II are devoted to tests of general relativity and to many of its applications Binary pulsars are studied in considerable detail Much space is devoted to the study of compact objects, especially to black holes This includes a detailed derivation of the Kerr solution, Israel's proof of his uniqueness theorem, and derivations of the basic laws of black hole physics The final chapter of this part contains Witten's proof of the positive energy theorem The book addresses undergraduate and graduate students in physics, astrophysics and mathematics It is very well structured and should become a standard text for a modern treatment of gravitational physics The clear presentation of differential geometry makes it also useful for string theory and other fields of ...
A precise extragalactic test of General Relativity.
Collett, Thomas E; Oldham, Lindsay J; Smith, Russell J; Auger, Matthew W; Westfall, Kyle B; Bacon, David; Nichol, Robert C; Masters, Karen L; Koyama, Kazuya; van den Bosch, Remco
2018-06-22
Einstein's theory of gravity, General Relativity, has been precisely tested on Solar System scales, but the long-range nature of gravity is still poorly constrained. The nearby strong gravitational lens ESO 325-G004 provides a laboratory to probe the weak-field regime of gravity and measure the spatial curvature generated per unit mass, γ. By reconstructing the observed light profile of the lensed arcs and the observed spatially resolved stellar kinematics with a single self-consistent model, we conclude that γ = 0.97 ± 0.09 at 68% confidence. Our result is consistent with the prediction of 1 from General Relativity and provides a strong extragalactic constraint on the weak-field metric of gravity. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.
Generalized Weierstrass Relations and Frobenius Reciprocity
International Nuclear Information System (INIS)
Matsutani, Shigeki
2006-01-01
This article investigates local properties of the further generalized Weierstrass relations for a spin manifold S immersed in a higher dimensional spin manifold M from the viewpoint of the study of submanifold quantum mechanics. We show that the kernel of a certain Dirac operator defined over S, which we call a submanifold Dirac operator, gives the data of the immersion. In the derivation, the simple Frobenius reciprocity of Clifford algebras S and M plays an important role
Screening vector field modifications of general relativity
International Nuclear Information System (INIS)
Beltrán Jiménez, Jose; Delvas Fróes, André Luís; Mota, David F.
2013-01-01
A screening mechanism for conformal vector–tensor modifications of general relativity is proposed. The conformal factor depends on the norm of the vector field and makes the field to vanish in high dense regions, whereas drives it to a non-null value in low density environments. Such process occurs due to a spontaneous symmetry breaking mechanism and gives rise to both the screening of fifth forces as well as Lorentz violations. The cosmology and local constraints are also computed
Interacting electromagnetic waves in general relativity
International Nuclear Information System (INIS)
Griffiths, J.B.
1976-01-01
The problem is considered of finding exact solutions of the Einstein-Maxwell equations which describe the physical situation of two colliding and subsequently interacting electromagnetic waves. The general theory of relativity predicts a nonlinear interaction between electromagnetic waves. The situation is described using an approximate geometrical method, and a new exact solution describing two interacting electromagnetic waves is given. This describes waves emitted from two sources mutually focusing each other on the opposite source. (author)
Testing General Relativity with Pulsar Timing
Directory of Open Access Journals (Sweden)
Stairs Ingrid H.
2003-01-01
Full Text Available Pulsars of very different types, including isolated objects and binaries (with short- and long-period orbits, and white-dwarf and neutron-star companions provide the means to test both the predictions of general relativity and the viability of alternate theories of gravity. This article presents an overview of pulsars, then discusses the current status of and future prospects for tests of equivalence-principle violations and strong-field gravitational experiments.
Probing the Higgs vacuum with general relativity
Mannheim, Philip D.; Kazanas, Demosthenes
1991-01-01
It is shown that the structure of the Higgs vacuum can be revealed in gravitational experiments which probe the Schwarzschild geometry to only one order in MG/r beyond that needed for the classical tests of general relativity. The possibility that deviations from the conventional geometry are at least theoretically conceivable is explored. The deviations obtained provide a diagnostic test for searching for the existence of macroscopic scalar fields and open up the possiblity for further exploring the Higgs mechanism.
Special relativity, electrodynamics, and general relativity from Newton to Einstein
Kogut, John B
2018-01-01
Special Relativity, Electrodynamics and General Relativity: From Newton to Einstein, Second Edition, is intended to teach (astro)physics, astronomy, and cosmology students how to think about special and general relativity in a fundamental, but accessible, way. Designed to render any reader a "master of relativity," everything on the subject is comprehensible and derivable from first principles. The book emphasizes problem solving, contains abundant problem sets, and is conveniently organized to meet the needs of both student and instructor. Fully revised, updated and expanded second edition Includes new chapters on magnetism as a consequence of relativity and electromagnetism Contains many improved and more engaging figures Uses less algebra resulting in more efficient derivations Enlarged discussion of dynamics and the relativistic version of Newton's second law
Quantum theory and Einstein's general relativity
International Nuclear Information System (INIS)
Borzeszkowski, H. von; Treder, H.
1982-01-01
We dicusss the meaning and prove the accordance of general relativity, wave mechanics, and the quantization of Einstein's gravitation equations themselves. Firstly, we have the problem of the influence of gravitational fields on the de Broglie waves, which influence is in accordance with Einstein's weak principle of equivalence and the limitation of measurements given by Heisenberg's uncertainty relations. Secondly, the quantization of the gravitational fields is a ''quantization of geometry.'' However, classical and quantum gravitation have the same physical meaning according to limitations of measurements given by Einstein's strong principle of equivalence and the Heisenberg uncertainties for the mechanics of test bodies
Relativity the special and the general theory
Einstein, Albert
2015-01-01
After completing the final version of his general theory of relativity in November 1915, Albert Einstein wrote a book about relativity for a popular audience. His intention was "to give an exact insight into the theory of relativity to those readers who, from a general scientific and philosophical point of view, are interested in the theory, but who are not conversant with the mathematical apparatus of theoretical physics." The book remains one of the most lucid explanations of the special and general theories ever written. In the early 1920s alone, it was translated into ten languages, and fifteen editions in the original German appeared over the course of Einstein's lifetime. This new edition of Einstein's celebrated book features an authoritative English translation of the text along with an introduction and a reading companion by Hanoch Gutfreund and Jürgen Renn that examines the evolution of Einstein's thinking and casts his ideas in a broader present-day context. A special chapter explores the history...
Topics in the Foundations of General Relativity and Newtonian Gravitation Theory
Malament, David B
2012-01-01
In Topics in the Foundations of General Relativity and Newtonian Gravitation Theory, David B. Malament presents the basic logical-mathematical structure of general relativity and considers a number of special topics concerning the foundations of general relativity and its relation to Newtonian gravitation theory. These special topics include the geometrized formulation of Newtonian theory (also known as Newton-Cartan theory), the concept of rotation in general relativity, and Gödel spacetime. One of the highlights of the book is a no-go theorem that can be understood to show that there is
International Nuclear Information System (INIS)
Iimori, Yuki; Torii, Shingo
2015-01-01
Developing the analysis in http://dx.doi.org/10.1007/JHEP03(2014)044 [http://arxiv.org/abs/1312.1677] by the present authors et al., we clarify the relation between the Witten formulation and the Berkovits formulation of open superstring field theory at the level of the master action, namely the solution to the classical master equation in the Batalin-Vilkovisky formalism, which is the key for the path-integral quantization. We first scrutinize the reducibility structure, a detailed gauge structure containing the information about ghost string fields. Then, extending the condition for partial gauge fixing introduced in the above-mentioned paper to the sector of ghost string fields, we investigate the master action. We show that the reducibility structure and the master action under partial gauge fixing of the Berkovits formulation can be regarded as the regularized versions of those in the Witten formulation.
International Nuclear Information System (INIS)
Yu Watanabe; Masahito Ueda
2012-01-01
Full text: When we try to obtain information about a quantum system, we need to perform measurement on the system. The measurement process causes unavoidable state change. Heisenberg discussed a thought experiment of the position measurement of a particle by using a gamma-ray microscope, and found a trade-off relation between the error of the measured position and the disturbance in the momentum caused by the measurement process. The trade-off relation epitomizes the complementarity in quantum measurements: we cannot perform a measurement of an observable without causing disturbance in its canonically conjugate observable. However, at the time Heisenberg found the complementarity, quantum measurement theory was not established yet, and Kennard and Robertson's inequality erroneously interpreted as a mathematical formulation of the complementarity. Kennard and Robertson's inequality actually implies the indeterminacy of the quantum state: non-commuting observables cannot have definite values simultaneously. However, Kennard and Robertson's inequality reflects the inherent nature of a quantum state alone, and does not concern any trade-off relation between the error and disturbance in the measurement process. In this talk, we report a resolution to the complementarity in quantum measurements. First, we find that it is necessary to involve the estimation process from the outcome of the measurement for quantifying the error and disturbance in the quantum measurement. We clarify the implicitly involved estimation process in Heisenberg's gamma-ray microscope and other measurement schemes, and formulate the error and disturbance for an arbitrary quantum measurement by using quantum estimation theory. The error and disturbance are defined in terms of the Fisher information, which gives the upper bound of the accuracy of the estimation. Second, we obtain uncertainty relations between the measurement errors of two observables [1], and between the error and disturbance in the
An Introduction to General Relativity and Cosmology
International Nuclear Information System (INIS)
Wainwright, John
2007-01-01
The present volume is an introduction to general relativity and cosmology, at a level suitable for beginning graduate students or advanced undergraduates. The book consists of two main parts, the first entitled 'Elements of differential geometry', and the second 'The theory of gravitation'. Chapters 2-7, part I, introduce the basic ideas of differential geometry in a general setting, and are based on previously unpublished notes by one of the authors. On the one hand, the treatment is modern in that it uses a 'top-down' approach, i.e. starting with general differentiable manifolds, and deferring the introduction of a metric tensor until after the notions of affine connection and curvature have been introduced. On the other hand, the treatment is classical in that it relies heavily, though not exclusively, on index notation. The general material, chapters 1-7, is then followed by four more specialized chapters dealing with matters of specific interest for general relativity. Part II deals with general relativity and cosmology. The basic assumptions of the theory and its application to spherically symmetric gravitational fields are discussed in two chapters, and there is some historical material and motivation for the basic assumptions at the beginning of the book. The final chapter contains a detailed discussion of the Kerr solution. But the main emphasis in part II is on relativistic cosmology, in particular the analysis of cosmological models more general than the familiar Friedmann-Lemaitre (FL) models. The material on cosmology begins with a discussion of relativistic hydrodynamics and thermodynamics. The kinematical quantities (rate of expansion, shear, etc, of a timelike congruence) are introduced and their evolution equations are derived. There follows a description of the fluid model of the Universe and optical observations in such a model, within the framework of a general spacetime geometry. The discussion is subsequently specialized to the Robertson
Energy conditions and stability in general relativity
International Nuclear Information System (INIS)
Hall, G.S.
1982-01-01
The dominant energy condition in general relativity theory, which says that every observer measures a nonnegative local energy density and a nonspacelike local energy flow, is examined in connection with the types of energy-momentum tensor it permits. The condition that the energy-momentum tensor be ''stable'' in obeying the dominant energy conditions is then defined in terms of a suitable topology on the set of energy-momentum tensors on space-time and the consequences are evaluated and discussed. (author)
Weak field approximation of new general relativity
International Nuclear Information System (INIS)
Fukui, Masayasu; Masukawa, Junnichi
1985-01-01
In the weak field approximation, gravitational field equations of new general relativity with arbitrary parameters are examined. Assuming a conservation law delta sup(μ)T sub(μν) = 0 of the energy-momentum tensor T sub(μν) for matter fields in addition to the usual one delta sup(ν)T sub(μν) = 0, we show that the linearized gravitational field equations are decomposed into equations for a Lorentz scalar field and symmetric and antisymmetric Lorentz tensor fields. (author)
The mathematical theory of general relativity
Katkar, L N
2014-01-01
This book is prepared for M. Sc. Students of Mathematics and Physics. The aim of writing this book is to give the reader a feeling for the necessity and beauty of the laws of general relativity. The contents of the book will attract both mathematicians and physicists which provides motivation and applications of many ideas and powerful mathematical methods of modern analysis and differential geometry. An attempt has been made to make the presentation comprehensive, rigorous and yet simple. Most calculations and transformations have been carried out in great detail. KEY FEATURE: Numerous solved examples using the well known mathematical techniques viz., the tensors and the differential forms in each chapter.
Tests of General Relativity with GW150914
Abbott, B. P.; Abbott, R.; Abernathy, M. R.; Adhikari, R. X.; Anderson, S. B.; Arai, K.; Araya, M. C.; Barayoga, J. C.; Barish, B. C.; Berger, B. K.; Billingsley, G.; Blackburn, J. K.; Bork, R.; Brooks, A. F.; Cahillane, C.
2016-01-01
The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant’s mass and spin, as determined fro...
New Area Law in General Relativity.
Bousso, Raphael; Engelhardt, Netta
2015-08-21
We report a new area law in general relativity. A future holographic screen is a hypersurface foliated by marginally trapped surfaces. We show that their area increases monotonically along the foliation. Future holographic screens can easily be found in collapsing stars and near a big crunch. Past holographic screens exist in any expanding universe and obey a similar theorem, yielding the first rigorous area law in big bang cosmology. Unlike event horizons, these objects can be identified at finite time and without reference to an asymptotic boundary. The Bousso bound is not used, but it naturally suggests a thermodynamic interpretation of our result.
A new topical formulation enhances relative diclofenac bioavailability in healthy male subjects.
Brunner, Martin; Davies, David; Martin, Wolfgang; Leuratti, Chiara; Lackner, Edith; Müller, Markus
2011-06-01
• Therapy with topical non-steroidal anti-inflammatory drugs (NSAIDs) relies on the ability of the active drug to penetrate the skin in sufficiently high amounts to exert a clinical effect, which is linked to the specific galenic properties of the formulation. • This phase 1 study characterizes the transdermal penetration and plasma exposure of different dose levels with galenic differences of a novel topical diclofenac formulation under development and indicates greater diclofenac penetration through the skin when compared with a commercially available formulation. To evaluate the relative plasma and tissue availability of diclofenac after repeated topical administration of a novel diclofenac acid-based delivery system under development (DCF100C). This was a single-centre, open-label, three-period, crossover clinical trial of five discrete diclofenac formulations. Test preparations comprised two concentrations (1.0% and 2.5%) of DCF100C, with and without menthol and eucalyptus oil (total daily doses of 5 mg and 12.5 mg). Voltaren Emulgel gel (1.0%) was the commercially available comparator (total daily dose of 40 mg). Topical application was performed onto the thigh of 20 male healthy subjects for 3 days. Applying a Youden square design, each drug was evaluated in 12 subjects, with each subject receiving three test preparations. Blood sampling and in vivo microdialysis in subcutaneous adipose and skeletal muscle tissues were performed for 10 h after additional final doses on the morning of day 4. All four DCF100C formulations demonstrated a three- to fivefold, dose-dependent increase in systemic diclofenac availability compared with Voltaren Emulgel and were approximately 30-40 times more effective at facilitating diclofenac penetration through the skin, taking different dose levels into account. Tissue concentrations were low and highly variable. The 2.5% DCF100C formulation without sensory excipients reached the highest tissue concentrations. AUC(0,10 h) was
Anholonomic Cauchy problem in general relativity
International Nuclear Information System (INIS)
Stachel, J.
1980-01-01
The Lie derivative approach to the Cauchy problem in general relativity is applied to the evolution along an arbitrary timelike vector field for the case where the dynamical degrees of freedom are chosen as the (generally anholonomic) metric of the hypersurface elements orthogonal to the vector field. Generalizations of the shear, rotation, and acceleration are given for a nonunit timelike vector field, and applied to the three-plus-one breakup of the Riemann tensor into components parallel and orthogonal to the vector field, resulting in the anholonomic Gauss--Codazzi equations. A similar breakup of the Einstein field equations results in the form of the constraint and evolution equations for the anholonomic case. The results are applied to the case of a space--time with a timelike Killing vector field (stationary field) to demonstrate their utility. Other possible applications, such as in the numerical integration of the field equations, are mentioned. Definitions are given of three-index shear, rotation, and acceleration tensors, and their use in a two-plus-two decomposition of the Riemann tensor and field equations is indicated
Introduction to general relativity and cosmology
Berger, Mitchell A
2018-01-01
The textbook aims to present general relativity and modern cosmology in a friendly form suitable for advanced undergraduates. The text begins with a self-contained introduction to the theory of manifolds and then develops the tools needed to understand curved spaces and curved spacetimes. Special relativity can then be understood in a geometrical context, bypassing some of the difficulties students have when encountering relativistic effects (e.g. time dilation and length contraction) for the first time. The theory of curvature and its effects leads to the Einstein field equations and its classic tests in the precession of Mercury and the deflection of starlight. The second part of the book covers modern cosmology, starting with the evolution equations for the expansion of the universe. The microwave background, evidence for dark matter, and the clustering of galaxies are examined in detail.
Free and constrained symplectic integrators for numerical general relativity
International Nuclear Information System (INIS)
Richter, Ronny; Lubich, Christian
2008-01-01
We consider symplectic time integrators in numerical general relativity and discuss both free and constrained evolution schemes. For free evolution of ADM-like equations we propose the use of the Stoermer-Verlet method, a standard symplectic integrator which here is explicit in the computationally expensive curvature terms. For the constrained evolution we give a formulation of the evolution equations that enforces the momentum constraints in a holonomically constrained Hamiltonian system and turns the Hamilton constraint function from a weak to a strong invariant of the system. This formulation permits the use of the constraint-preserving symplectic RATTLE integrator, a constrained version of the Stoermer-Verlet method. The behavior of the methods is illustrated on two effectively (1+1)-dimensional versions of Einstein's equations, which allow us to investigate a perturbed Minkowski problem and the Schwarzschild spacetime. We compare symplectic and non-symplectic integrators for free evolution, showing very different numerical behavior for nearly-conserved quantities in the perturbed Minkowski problem. Further we compare free and constrained evolution, demonstrating in our examples that enforcing the momentum constraints can turn an unstable free evolution into a stable constrained evolution. This is demonstrated in the stabilization of a perturbed Minkowski problem with Dirac gauge, and in the suppression of the propagation of boundary instabilities into the interior of the domain in Schwarzschild spacetime
Mechanics of extended masses in general relativity
International Nuclear Information System (INIS)
Harte, Abraham I
2012-01-01
The 'external' or 'Right' motion of extended bodies is studied in general relativity. Compact material objects of essentially arbitrary shape, spin, internal composition and velocity are allowed as long as there is no direct (non-gravitational) contact with other sources of stress-energy. Physically reasonable linear and angular momenta are proposed for such bodies and exact equations describing their evolution are derived. Changes in the momenta depend on a certain 'effective metric' that is closely related to a non-perturbative generalization of the Detweiler-Whiting R-field originally introduced in the self-force literature. If the effective metric inside a self-gravitating body can be adequately approximated by an appropriate power series, the instantaneous gravitational force and torque exerted on it is shown to be identical to the force and torque exerted on an appropriate test body moving in the effective metric. This result holds to all multipole orders. The only instantaneous effect of a body's self-field is to finitely renormalize the 'bare' multipole moments of its stress-energy tensor. The MiSaTaQuWa expression for the gravitational self-force is recovered as a simple application. A gravitational self-torque is obtained as well. Lastly, it is shown that the effective metric in which objects appear to move is approximately a solution to the vacuum Einstein equation if the physical metric is an approximate solution to Einstein's equation linearized about a vacuum background. (paper)
Optical drift effects in general relativity
Korzyński, Mikołaj; Kopiński, Jarosław
2018-03-01
We consider the question of determining the optical drift effects in general relativity, i.e. the rate of change of the apparent position, redshift, Jacobi matrix, angular distance and luminosity distance of a distant object as registered by an observer in an arbitrary spacetime. We present a fully relativistic and covariant approach, in which the problem is reduced to a hierarchy of ODE's solved along the line of sight. The 4-velocities and 4-accelerations of the observer and the emitter and the geometry of the spacetime along the line of sight constitute the input data. We build on the standard relativistic geometric optics formalism and extend it to include the time derivatives of the observables. In the process we obtain two general, non-perturbative relations: the first one between the gravitational lensing, represented by the Jacobi matrix, and the apparent position drift, also called the cosmic parallax, and the second one between the apparent position drift and the redshift drift. The applications of the results include the theoretical study of the drift effects of cosmological origin (so-called real-time cosmology) in numerical or exact Universe models.
Kinematics in special and general relativity
International Nuclear Information System (INIS)
Woodside, R.W.M.
1979-05-01
This thesis investigates the problem of motion for extended bodies from the viewpoint of classical field theory, where the classical field is the body's energy-momentum or matter tensor. In special relativity a symmetric and divergence-free matter tensor combined with inertial frames is used to generate a kinematics for extended bodies. In general relativity the author suggests an analogous kinematics and applies it to the simplest non-trivial example of static, spherical stars, looking for special sets of vector fields whose matter currents are conserved. Such a set of ten vector fields defines a special frame, and integrals of the conserved matter currents define ten momenta whcih give the kinematics. Application of de Rham cohomology theory shows that the conserved matter currents for isolated bodies will have mechanical potentials which enable the momenta to be found from flux integrals evaluated in the vacuum region surrounding the body. These potentials contain the full Riemann curvature, allowing a body's general relativistic momenta to be determined by its vacuum graviational field
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Réville, Victor; Brun, Allan Sacha; Strugarek, Antoine; Pinto, Rui F. [Laboratoire AIM, DSM/IRFU/SAp, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France); Matt, Sean P., E-mail: victor.reville@cea.fr, E-mail: sacha.brun@cea.fr, E-mail: s.matt@exeter.ac.uk, E-mail: strugarek@astro.umontreal.ca, E-mail: rui.pinto@obspm.fr [Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4SB (United Kingdom)
2015-01-10
Stellar wind is thought to be the main process responsible for the spin down of main-sequence stars. The extraction of angular momentum by a magnetized wind has been studied for decades, leading to several formulations for the resulting torque. However, previous studies generally consider simple dipole or split monopole stellar magnetic topologies. Here we consider, in addition to a dipolar stellar magnetic field, both quadrupolar and octupolar configurations, while also varying the rotation rate and the magnetic field strength. Sixty simulations made with a 2.5D cylindrical and axisymmetric set-up, and computed with the PLUTO code, were used to find torque formulations for each topology. We further succeed to give a unique law that fits the data for every topology by formulating the torque in terms of the amount of open magnetic flux in the wind. We also show that our formulation can be applied to even more realistic magnetic topologies, with examples of the Sun in its minimum and maximum phases as observed at the Wilcox Solar Observatory, and of a young K-star (TYC-0486-4943-1) whose topology has been obtained by Zeeman-Doppler Imaging.
International Nuclear Information System (INIS)
Reshetnyak, A.
2013-01-01
We continue the construction of a Lagrangian description of irreducible half-integer higher-spin representations of the Poincare group with an arbitrary Young tableaux having k rows, on a basis of the BRST–BFV approach suggested for bosonic fields in our first article [I.L. Buchbinder, A. Reshetnyak, Nucl. Phys. B 862 (2012) 270, (arXiv:1110.5044 [hep-th])]. Starting from a description of fermionic mixed-symmetry higher-spin fields in a flat space of any dimension in terms of an auxiliary Fock space associated with a special Poincare module, we realize a conversion of the initial operator constraint system (constructed with respect to the relations extracting irreducible Poincare-group representations) into a system of first-class constraints. To do this, we find, in first time, by means of generalized Verma module the auxiliary representations of the constraint subsuperalgebra, to be isomorphic due to Howe duality to osp(k|2k) superalgebra, and containing the subsystem of second-class constraints in terms of new oscillator variables. We suggest a universal procedure of finding unconstrained gauge-invariant Lagrangians with reducible gauge symmetries, describing the dynamics of both massless and massive fermionic fields of any spin. It is shown that the space of BRST cohomologies with a vanishing ghost number is determined only by constraints corresponding to an irreducible Poincare-group representation. As examples of the general approach, we propose a method of Lagrangian construction for fermionic fields subject to an arbitrary Young tableaux having 3 rows, and obtain a gauge-invariant Lagrangian for a new model of a massless rank-3 spin-tensor field of spin (5/2,3/2) with first-stage reducible gauge symmetries and a non-gauge Lagrangian for a massive rank-3 spin-tensor field of spin (5/2,3/2)
Kinematics of relative motion of test particles in general relativity
International Nuclear Information System (INIS)
Bazanski, S.L.
1977-01-01
A detailed mathematical study of the concept of geodesic deviation in pseudo-riemannian geometry is presented. A generalization of this concept to geodesic deviations of a higher order is then introduced and the second geodesic deviation is investigated in some detail. A geometric interpretation of the set of generalized geodesic deviations is given and applied in general relativity to determine a covariant and local description (with a desired order of accuracy) of test motions which take place in a certain finite neighbourhood of a given world line of an observer. The proper time evolution of two other objects related to geodesic deviation is also discussed: the space separation vector and the telescopic vector. This last name is given here to a field of null vectors along observer's world line which always point towards the same adjacent world line. The telescopic equations allow to determine the evolution of the frequency shift of electromagnetic radiation sent from and received on neighbouring world lines. On the basis of these equations also certain relations have been derived which connect the frequencies or frequency shifts with the curvature of space-time
A new topical formulation enhances relative diclofenac bioavailability in healthy male subjects
Brunner, Martin; Davies, David; Martin, Wolfgang; Leuratti, Chiara; Lackner, Edith; Müller, Markus
2011-01-01
AIMS To evaluate the relative plasma and tissue availability of diclofenac after repeated topical administration of a novel diclofenac acid-based delivery system under development (DCF100C). METHODS This was a single-centre, open-label, three-period, crossover clinical trial of five discrete diclofenac formulations. Test preparations comprised two concentrations (1.0% and 2.5%) of DCF100C, with and without menthol and eucalyptus oil (total daily doses of 5 mg and 12.5 mg). Voltaren® Emulgel® gel (1.0%) was the commercially available comparator (total daily dose of 40 mg). Topical application was performed onto the thigh of 20 male healthy subjects for 3 days. Applying a Youden square design, each drug was evaluated in 12 subjects, with each subject receiving three test preparations. Blood sampling and in vivo microdialysis in subcutaneous adipose and skeletal muscle tissues were performed for 10 h after additional final doses on the morning of day 4. RESULTS All four DCF100C formulations demonstrated a three- to fivefold, dose-dependent increase in systemic diclofenac availability compared with Voltaren® Emulgel® and were approximately 30–40 times more effective at facilitating diclofenac penetration through the skin, taking different dose levels into account. Tissue concentrations were low and highly variable. The 2.5% DCF100C formulation without sensory excipients reached the highest tissue concentrations. AUC(0,10 h) was 2.71 times greater than for Voltaren® Emulgel® (90% CI 99.27, 737.46%). Mild erythema at the application site was the most frequent adverse event associated with DCF100C. There were no local symptoms after treatment with the reference formulation. CONCLUSION DCF100C formulations were safe and facilitated greater diclofenac penetration through the skin compared with the commercial comparator. DCF100C represents a promising alternative to oral and topical diclofenac treatments that warrants further development. PMID:21241352
An elementary course on general relativity
International Nuclear Information System (INIS)
Regge, T.
1983-01-01
This report gives an informal account of the theory of general relativity, for non-specialists. It does not contain any detailed technical expose of tensor calculus but relies instead on a number of intuitive arguments. After a brief historical introduction the notion of curvature is developed, first in two dimensions (as done originally by Gauss) and then in higher dimensions, following the ideas of Riemann. This curvature is then related to quantities of physical interest through the following steps: i) The equality of gravitational and inertial masses is discussed and presented as the ''weak equivalence principle''. ii) This is then extended to the ''strong equivalence principle'' according to the original programme of Einstein. iii) The ''strong equivalence principle'' implies the existence of a local inertial observer in any point of space-time. In a sufficiently small region of space-time this observer will not sense any gravitational field. iv) In a larger region the observer will, however, sense residual tidal forces. These forces are identified with the curvature of spacetime, to achieve a direct geometrical interpretation of gravity. v) Finally certain curvature components are related to the distribution of matter through Einstein's field equations. Section 4 contains a discussion of the classical tests of the theory and of the possibility of detecting gravitational waves. Sections 5 and 6 deal with cosmology and with the possible extension of the theory along the lines of the original ideas of Einstein, with emphasis on the dimensional reduction techniques of current interest. (orig.)
General Relativity solutions in modified gravity
Motohashi, Hayato; Minamitsuji, Masato
2018-06-01
Recent gravitational wave observations of binary black hole mergers and a binary neutron star merger by LIGO and Virgo Collaborations associated with its optical counterpart constrain deviation from General Relativity (GR) both on strong-field regime and cosmological scales with high accuracy, and further strong constraints are expected by near-future observations. Thus, it is important to identify theories of modified gravity that intrinsically possess the same solutions as in GR among a huge number of theories. We clarify the three conditions for theories of modified gravity to allow GR solutions, i.e., solutions with the metric satisfying the Einstein equations in GR and the constant profile of the scalar fields. Our analysis is quite general, as it applies a wide class of single-/multi-field scalar-tensor theories of modified gravity in the presence of matter component, and any spacetime geometry including cosmological background as well as spacetime around black hole and neutron star, for the latter of which these conditions provide a necessary condition for no-hair theorem. The three conditions will be useful for further constraints on modified gravity theories as they classify general theories of modified gravity into three classes, each of which possesses i) unique GR solutions (i.e., no-hair cases), ii) only hairy solutions (except the cases that GR solutions are realized by cancellation between singular coupling functions in the Euler-Lagrange equations), and iii) both GR and hairy solutions, for the last of which one of the two solutions may be selected dynamically.
Dynamical laws of superenergy in general relativity
International Nuclear Information System (INIS)
Gomez-Lobo, Alfonso GarcIa-Parrado
2008-01-01
The Bel and Bel-Robinson tensors were introduced nearly 50 years ago in an attempt to generalize to gravitation the energy-momentum tensor of electromagnetism. This generalization was successful from the mathematical point of view because these tensors share mathematical properties which are remarkably similar to those of the energy-momentum tensor of electromagnetism. However, the physical role of these tensors in general relativity has remained obscure and no interpretation has achieved wide acceptance. In principle, they cannot represent energy and the term superenergy has been coined for the hypothetical physical magnitude lying behind them. In this work, we try to shed light on the true physical meaning of superenergy by following the same procedure which enables us to give an interpretation of the electromagnetic energy. This procedure consists in performing an orthogonal splitting of the Bel and Bel-Robinson tensors and analyzing the different parts resulting from the splitting. In the electromagnetic case such splitting gives rise to the electromagnetic energy density, the Poynting vector and the electromagnetic stress tensor, each of them having a precise physical interpretation which is deduced from the dynamical laws of electromagnetism (Poynting theorem). The full orthogonal splitting of the Bel and Bel-Robinson tensors is more complex but, as expected, similarities with electromagnetism are present. Also the covariant divergence of the Bel tensor is analogous to the covariant divergence of the electromagnetic energy-momentum tensor and the orthogonal splitting of the former is found. The ensuing equations are to the superenergy what the Poynting theorem is to electromagnetism. Some consequences of these dynamical laws of superenergy are explored, among them the possibility of defining superenergy radiative states for the gravitational field
On multipole moments in general relativity
International Nuclear Information System (INIS)
Hoenselaers, C.
1986-01-01
In general situations, involving gravitational waves the question of multiple moments in general relativity restricts the author to stationary axisymmetric situations. Here it has been shown that multipole moments, a set of numbers defined at spatial infinity as far away from the source as possible, determine a solution of Einstein's equations uniquely. With the rather powerful methods for generating solutions one might hope to get solutions with predefined multipole moments. Before doing so, however, one needs an efficient algorithm for calculating the moments of a given solution. Chapter 2 deals with a conjecture pertaining to such a calculational procedure and shows it to be not true. There is another context in which multipole moments are important. Consider a system composed of several objects. To separate, if possible, the various parts of their interaction, one needs a definition for multipole moments of individual members of a many body system. In spite of the fact that there is no definition for individual moments, with the exception of mass and angular momentum, Chapter 3 shows what can be done for the double Kerr solution. The authors can identify various terms in he interaction of two aligned Kerr objects and show that gravitational spin-spin interaction is indeed proportional to the product of the angular momenta
Victories and defeats in general relativity theory
International Nuclear Information System (INIS)
Moeller, C.
1977-01-01
Only within the last 20 years has it been possible to conduct far-reaching experimental tests of the validity of Einstein's General Relativity Theory. Experimental confirmation in some fields is embarrassed by considerable difficulties in applying the theory to cosmic systems, which indicate that such major systems lie at the limit of the theory's applicability. The lecture here reproduced discusses both the successes and the limitations of the theory, starting with its replacement of the absolute space-time theory of Newton and its historical replacement by the relativistic gravitational postulates of Einstein which, in spite of its more complicated postulates, nevertheless introduced a great simplicity and comprehensiveness into the overall conception of nature. This theoretical 'beauty', however, can only be trusted if vindicated experimentally, which has to a considerable extent proved to be the case. For weak fields Newtonian and Einsteinian concepts coincide, while for stronger fields, and velocities not far from that of light, Einstein's theory is superior, giving,for example, an excellent correspondence with the precession of the perehelion of Mercury. On a larger scale, however, the theory appears to lead to conclusions which would invalidate the very concepts of space and time, even within a finite time-interval. A more generalized theory seems to be required. (A.D.N.)
Rotating Quark Stars in General Relativity
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Enping Zhou
2018-03-01
Full Text Available We have built quasi-equilibrium models for uniformly rotating quark stars in general relativity. The conformal flatness approximation is employed and the Compact Object CALculator (cocal code is extended to treat rotating stars with surface density discontinuity. In addition to the widely used MIT bag model, we have considered a strangeon star equation of state (EoS, suggested by Lai and Xu, that is based on quark clustering and results in a stiff EoS. We have investigated the maximum mass of uniformly rotating axisymmetric quark stars. We have also built triaxially deformed solutions for extremely fast rotating quark stars and studied the possible gravitational wave emission from such configurations.
Motivations for antigravity in General Relativity
Energy Technology Data Exchange (ETDEWEB)
Chardin, G. [DSM/DAPNIA/SPP, CEN-Saclay (France)
1997-08-15
We present arguments showing that it is natural to interpret the negative mass part of the Kerr solution as representing the geometry experienced by antimatter. The C, P and T discrete transformations are considered for this geometry. The C and T properties of the proposed identification are found to be in agreement with the usual representation of antimatter. In addition, we conjecture a property of perfect stigmatism through Kerr wormholes which allows General Relativity to mimic antigravity. Kerr wormholes would then act as 'supermirrors' reversing the C, P and T images of an object seen through it. This interpretation is subject to several experimental tests and able to provide an explanation, without any free parameter, of the 'CP' violation observed in the neutral kaon system.
Motivations for antigravity in General Relativity
International Nuclear Information System (INIS)
Chardin, G.
1997-01-01
We present arguments showing that it is natural to interpret the negative mass part of the Kerr solution as representing the geometry experienced by antimatter. The C, P and T discrete transformations are considered for this geometry. The C and T properties of the proposed identification are found to be in agreement with the usual representation of antimatter. In addition, we conjecture a property of perfect stigmatism through Kerr wormholes which allows General Relativity to mimic antigravity. Kerr wormholes would then act as 'supermirrors' reversing the C, P and T images of an object seen through it. This interpretation is subject to several experimental tests and able to provide an explanation, without any free parameter, of the 'CP' violation observed in the neutral kaon system
On thick domain walls in general relativity
Goetz, Guenter; Noetzold, Dirk
1989-01-01
Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.
On the relation of the theoretical foundations of quantum theory and general relativity theory
International Nuclear Information System (INIS)
Kober, Martin
2010-01-01
The specific content of the present thesis is presented in the following way. First the most important contents of quantum theory and general relativity theory are presented. In connection with the general relativity theory the mathematical property of the diffeomorphism invariance plays the deciding role, while concerning the quantum theory starting from the Copenhagen interpretation first the measurement problem is treated, before basing on the analysis of concrete phenomena and the mathematical apparatus of quantum theory the nonlocality is brought into focus as an important property. This means that both theories suggest a relationalistic view of the nature of the space. This analysis of the theoretical foundations of quantum theory and general relativity theory in relation to the nature of the space obtains only under inclusion of Kant's philosophy and his analysis of the terms space and time as fundamental forms of perception its full persuasive power. Then von Weizsaeckers quantum theory of the ur-alternatives is presented. Finally attempts are made to apply the obtained knowledge to the question of the quantum-theoretical formulation of general relativity theory.
Mimetic Theory for Cell-Centered Lagrangian Finite Volume Formulation on General Unstructured Grids
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Sambasivan, Shiv Kumar [Los Alamos National Laboratory; Shashkov, Mikhail J. [Los Alamos National Laboratory; Burton, Donald E. [Los Alamos National Laboratory; Christon, Mark A. [Los Alamos National Laboratory
2012-07-19
A finite volume cell-centered Lagrangian scheme for solving large deformation problems is constructed based on the hypo-elastic model and using the mimetic theory. Rigorous analysis in the context of gas and solid dynamics, and arbitrary polygonal meshes, is presented to demonstrate the ability of cell-centered schemes in mimicking the continuum properties and principles at the discrete level. A new mimetic formulation based gradient evaluation technique and physics-based, frame independent and symmetry preserving slope limiters are proposed. Furthermore, a physically consistent dissipation model is employed which is both robust and inexpensive to implement. The cell-centered scheme along with these additional new features are applied to solve solids undergoing elasto-plastic deformation.
Singular Null Hypersurfaces in General Relativity
International Nuclear Information System (INIS)
Dray, T
2006-01-01
Null hypersurfaces are a mathematical consequence of the Lorentzian signature of general relativity; singularities in mathematical models usually indicate where the interesting physics takes place. This book discusses what happens when you combine these ideas. Right from the preface, this is a no-nonsense book. There are two principal approaches to singular shells, one distributional and the other 'cut and paste'; both are treated in detail. A working knowledge of GR is assumed, including familiarity with null tetrads, differential forms, and 3 + 1 decompositions. Despite my own reasonably extensive, closely related knowledge, there was material unfamiliar to me already in chapter 3, although I was reunited with some old friends in later chapters. The exposition is crisp, with a minimum of transition from chapter to chapter. In fact, my main criticism is that there is no clear statement of the organization of the book, nor is there an index. Everything is here, and the story is compelling if you know what to look for, although it is less easy to follow the story if you are not already familiar with it. But this is really a book for experts, and the authors certainly qualify, having played a significant role in developing and extending the results they describe. It is also entirely appropriate that the book is dedicated to Werner Israel, who pioneered the thin-shell approach to (non-null) singular surfaces and later championed the use of similar methods for analysing null shells. After an introductory chapter on impulsive signals, the authors show how the Bianchi identities can be used to classify spacetimes with singular null hypersurfaces. This approach, due to the authors, generalizes the framework originally proposed by Penrose. While astrophysical applications are discussed only briefly, the authors point out that detailed physical characteristics of signals from isolated sources can be determined in this manner. In particular, they describe the behaviour of
Axially symmetric Lorentzian wormholes in general relativity
International Nuclear Information System (INIS)
Schein, F.
1997-11-01
The field equations of Einstein's theory of general relativity, being local, do not fix the global structure of space-time. They admit topologically non-trivial solutions, including spatially closed universes and the amazing possibility of shortcuts for travel between distant regions in space and time - so-called Lorentzian wormholes. The aim of this thesis is to (mathematically) construct space-times which contain traversal wormholes connecting arbitrary distant regions of an asymptotically flat or asymptotically de Sitter universe. Since the wormhole mouths appear as two separate masses in the exterior space, space-time can at best be axially symmetric. We eliminate the non-staticity caused by the gravitational attraction of the mouths by anchoring them by strings held at infinity or, alternatively, by electric repulsion. The space-times are obtained by surgically grafting together well-known solutions of Einstein's equations along timelike hypersurfaces. This surgery naturally concentrates a non-zero stress-energy tensor on the boundary between the two space-times which can be investigated by using the standard thin shell formalism. It turns out that, when using charged black holes, the provided constructions are possible without violation of any of the energy conditions. In general, observers living in the axially symmetric, asymptotically flat (respectively asymptotically de Sitter) region axe able to send causal signals through the topologically non-trivial region. However, the wormhole space-times contain closed timelike curves. Because of this explicit violation of global hyperbolicity these models do not serve as counterexamples to known topological censorship theorems. (author)
Haj-Ali, Rami; Aboudi, Jacob
2012-01-01
The recent two-dimensional (2-D) parametric formulation of the high fidelity generalized method of cells (HFGMC) reported by the authors is generalized for the micromechanical analysis of three-dimensional (3-D) multiphase composites with periodic microstructure. Arbitrary hexahedral subcell geometry is developed to discretize a triply periodic repeating unit-cell (RUC). Linear parametric-geometric mapping is employed to transform the arbitrary hexahedral subcell shapes from the physical space to an auxiliary orthogonal shape, where a complete quadratic displacement expansion is performed. Previously in the 2-D case, additional three equations are needed in the form of average moments of equilibrium as a result of the inclusion of the bilinear terms. However, the present 3-D parametric HFGMC formulation eliminates the need for such additional equations. This is achieved by expressing the coefficients of the full quadratic polynomial expansion of the subcell in terms of the side or face average-displacement vectors. The 2-D parametric and orthogonal HFGMC are special cases of the present 3-D formulation. The continuity of displacements and tractions, as well as the equilibrium equations, are imposed in the average (integral) sense as in the original HFGMC formulation. Each of the six sides (faces) of a subcell has an independent average displacement micro-variable vector which forms an energy-conjugate pair with the transformed average-traction vector. This allows generating symmetric stiffness matrices along with internal resisting vectors for the subcells which enhances the computational efficiency. The established new parametric 3-D HFGMC equations are formulated and solution implementations are addressed. Several applications for triply periodic 3-D composites are presented to demonstrate the general capability and varsity of the present parametric HFGMC method for refined micromechanical analysis by generating the spatial distributions of local stress fields
Poisson, Eric
2010-05-01
as Lie differentiation, differential forms, Killing vectors, the more abstract formulation of differential geometry (in terms of charts and diffeomorphisms), and the Lagrangian formulation of general relativity. This limitation of scope is wise: Schutz masterly covers the essentials in an efficient and small package, and relegates all refinements to further reading in other textbooks; this is a sound learning strategy. To conclude I will state that I just love this book. I love it today as much as I did when I first came across it as an undergraduate student. The revisions bring the book up-to-date, and they ensure that Schutz's text will remain in the pantheon of introductory general relativity books for many years to come. References [1] Poisson E 2005 Review of Spacetime and Geometry: An Introduction to General Relativity, by S M Carroll Class. Quantum Grav. 22 4385-4386 [2] Weinberg S 1972 Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity (New York: Wiley) [3] Misner C W, Thorne K S, and Wheeler J A 1973 Gravitation (San Francisco, CA: Freeman) [4] Schutz B F 1985 A First Course in General Relativity (Cambridge: Cambridge University Press) [5] Wald R M 1984 General Relativity (Chicago : Chicago University Press) [6] Hartle J B 2003 Gravity: An Introduction to Einstein's General Relativity (San Francisco, CA: Addison-Wesley) [7] Carroll S 2003 Spacetime and Geometry: An Introduction to General Relativity (San Francisco, CA: Benjamin Cummings)
Direction dependent structures in general relativity
International Nuclear Information System (INIS)
Herberthson, M.
1993-01-01
This thesis deals with, within the theory of general relativity, asymptotic properties of certain types of space-times. Using conformal transformations, it is possible to describe asymptotic properties of a physical space-time in terms of the local behaviour of the new, rescaled space-time. One then uses so called direction dependent structures. We present two such structures and applications to them. One structure is used in the study of spacelike (or spatial) infinity. We discuss the asymptotic conditions on the gravitational and the electromagnetic field, especially the conditions put on directions corresponding to future and past null infinity. It is shown that these fields have desired physical properties. The other structure is used in connection with timelike infinity. Using this structure, we suggest a new definition of timelike infinity. This definition differs significantly from earlier definitions, and leads to the concept of asymptotically stationary space-times. We also suggest a definition of asymptotic flatness at future null infinity, and a definition of a black hole which is, in a sense, local. Both of these definitions fit nicely into the structure. (24 refs.)
Outer boundary as arrested history in general relativity
International Nuclear Information System (INIS)
Lau, Stephen R
2002-01-01
We present explicit outer boundary conditions for the canonical variables of general relativity. The conditions are associated with the causal evolution of a finite Cauchy domain, a so-called quasilocal boost, and they suggest a consistent scheme for modelling such an evolution numerically. The scheme involves a continuous boost in the spacetime orthogonal complement 'orthogonal' T p (B) of the tangent space T p (B) belonging to each point p on the system boundary B. We show how the boost rate may be computed numerically via equations similar to those appearing in canonical investigations of black-hole thermodynamics (although here holding at an outer two-surface rather than the bifurcate two-surface of a Killing horizon). We demonstrate the numerical scheme on a model example, the quasilocal boost of a spherical three-ball in Minkowski spacetime. Developing our general formalism with recent hyperbolic formulations of the Einstein equations in mind, we use Anderson and York's 'Einstein-Christoffel' hyperbolic system as the evolution equations for our numerical simulation of the model
Outer boundary as arrested history in general relativity
Lau, Stephen R.
2002-06-01
We present explicit outer boundary conditions for the canonical variables of general relativity. The conditions are associated with the causal evolution of a finite Cauchy domain, a so-called quasilocal boost, and they suggest a consistent scheme for modelling such an evolution numerically. The scheme involves a continuous boost in the spacetime orthogonal complement ⊥Tp(B) of the tangent space Tp(B) belonging to each point p on the system boundary B. We show how the boost rate may be computed numerically via equations similar to those appearing in canonical investigations of black-hole thermodynamics (although here holding at an outer two-surface rather than the bifurcate two-surface of a Killing horizon). We demonstrate the numerical scheme on a model example, the quasilocal boost of a spherical three-ball in Minkowski spacetime. Developing our general formalism with recent hyperbolic formulations of the Einstein equations in mind, we use Anderson and York's 'Einstein-Christoffel' hyperbolic system as the evolution equations for our numerical simulation of the model.
Outer boundary as arrested history in general relativity
Lau, S
2002-01-01
We present explicit outer boundary conditions for the canonical variables of general relativity. The conditions are associated with the causal evolution of a finite Cauchy domain, a so-called quasilocal boost, and they suggest a consistent scheme for modelling such an evolution numerically. The scheme involves a continuous boost in the spacetime orthogonal complement 'orthogonal' T sub p (B) of the tangent space T sub p (B) belonging to each point p on the system boundary B. We show how the boost rate may be computed numerically via equations similar to those appearing in canonical investigations of black-hole thermodynamics (although here holding at an outer two-surface rather than the bifurcate two-surface of a Killing horizon). We demonstrate the numerical scheme on a model example, the quasilocal boost of a spherical three-ball in Minkowski spacetime. Developing our general formalism with recent hyperbolic formulations of the Einstein equations in mind, we use Anderson and York's 'Einstein-Christoffel' hy...
Bende, Girish; Biswal, Shibadas; Bhad, Prafulla; Chen, Yuming; Salunke, Atish; Winter, Serge; Wagner, Robert; Sunkara, Gangadhar
2016-01-01
The oral bioavailability of diclofenac potassium 50 mg administered as a soft gelatin capsule (softgel capsule), powder for oral solution (oral solution), and tablet was evaluated in a randomized, open-label, 3-period, 6-sequence crossover study in healthy adults. Plasma diclofenac concentrations were measured using a validated liquid chromatography-mass spectrometry/mass spectrometry method, and pharmacokinetic analysis was performed by noncompartmental methods. The median time to achieve peak plasma concentrations of diclofenac was 0.5, 0.25, and 0.75 hours with the softgel capsule, oral solution, and tablet formulations, respectively. The geometric mean ratio and associated 90%CI for AUCinf, and Cmax of the softgel capsule formulation relative to the oral solution formulation were 0.97 (0.95-1.00) and 0.85 (0.76-0.95), respectively. The geometric mean ratio and associated 90%CI for AUCinf and Cmax of the softgel capsule formulation relative to the tablet formulation were 1.04 (1.00-1.08) and 1.67 (1.43-1.96), respectively. In conclusion, the exposure (AUC) of diclofenac with the new diclofenac potassium softgel capsule formulation was comparable to that of the existing oral solution and tablet formulations. The peak plasma concentration of diclofenac from the new softgel capsule was 67% higher than the existing tablet formulation, whereas it was 15% lower in comparison with the oral solution formulation. © 2015, The American College of Clinical Pharmacology.
Origins and development of the Cauchy problem in general relativity
International Nuclear Information System (INIS)
Ringström, Hans
2015-01-01
The seminal work of Yvonne Choquet-Bruhat published in 1952 demonstrates that it is possible to formulate Einstein's equations as an initial value problem. The purpose of this article is to describe the background to and impact of this achievement, as well as the result itself. In some respects, the idea of viewing the field equations of general relativity as a system of evolution equations goes back to Einstein himself; in an argument justifying that gravitational waves propagate at the speed of light, Einstein used a special choice of coordinates to derive a system of wave equations for the linear perturbations on a Minkowski background. Over the following decades, Hilbert, de Donder, Lanczos, Darmois and many others worked to put Einstein's ideas on a more solid footing. In fact, the issue of local uniqueness (giving a rigorous justification for the statement that the speed of propagation of the gravitational field is bounded by that of light) was already settled in the 1930s by the work of Stellmacher. However, the first person to demonstrate both local existence and uniqueness in a setting in which the notion of finite speed of propagation makes sense was Yvonne Choquet-Bruhat. In this sense, her work lays the foundation for the formulation of Einstein's equations as an initial value problem. Following a description of the results of Choquet-Bruhat, we discuss the development of three research topics that have their origin in her work. The first one is local existence. One reason for addressing it is that it is at the heart of the original paper. Moreover, it is still an active and important research field, connected to the problem of characterizing the asymptotic behaviour of solutions that blow up in finite time. As a second topic, we turn to the questions of global uniqueness and strong cosmic censorship. These questions are of fundamental importance to anyone interested in justifying that the Cauchy problem makes sense globally. They are
International Nuclear Information System (INIS)
Germain, M.; Toint, Ph.L.
2000-01-01
This paper proposes a game theoretical approach of international negotiations on transboundary pollution. This approach is distinguished by a discrete time formulation and by a suitable formulation of the local information assumption on cost and damage functions: at each stage of the negotiation, the parties assign the best possible cooperative state, given the available information, as an objective for the next stage. It is shown that the resulting sequences of states converges from a non-cooperative situation to an international optimum in a finite number of stages. Furthermore, a financial transfer structure is also presented that makes the desired sequence of states individually rational and strategically stable. The concepts are applied in a numerical simulation of the SO2 transboundary pollution problem related to acid rain in Northern Europe. 14 refs
General relativity invariance and string field theory
International Nuclear Information System (INIS)
Aref'eva, I.Ya.; Volovich, I.V.
1987-04-01
The general covariance principle in the string field theory is considered. The algebraic properties of the string Lie derivative are discussed. The string vielbein and spin connection are introduced and an action invariant under general co-ordinate transformation is proposed. (author). 18 refs
Gravitational Wave in Linear General Relativity
Cubillos, D. J.
2017-07-01
General relativity is the best theory currently available to describe the interaction due to gravity. Within Albert Einstein's field equations this interaction is described by means of the spatiotemporal curvature generated by the matter-energy content in the universe. Weyl worked on the existence of perturbations of the curvature of space-time that propagate at the speed of light, which are known as Gravitational Waves, obtained to a first approximation through the linearization of the field equations of Einstein. Weyl's solution consists of taking the field equations in a vacuum and disturbing the metric, using the Minkowski metric slightly perturbed by a factor ɛ greater than zero but much smaller than one. If the feedback effect of the field is neglected, it can be considered as a weak field solution. After introducing the disturbed metric and ignoring ɛ terms of order greater than one, we can find the linearized field equations in terms of the perturbation, which can then be expressed in terms of the Dalambertian operator of the perturbation equalized to zero. This is analogous to the linear wave equation in classical mechanics, which can be interpreted by saying that gravitational effects propagate as waves at the speed of light. In addition to this, by studying the motion of a particle affected by this perturbation through the geodesic equation can show the transversal character of the gravitational wave and its two possible states of polarization. It can be shown that the energy carried by the wave is of the order of 1/c5 where c is the speed of light, which explains that its effects on matter are very small and very difficult to detect.
A new formulation of the understeer coefficient to relate yaw torque and vehicle handling
Bucchi, F.; Frendo, F.
2016-06-01
The handling behaviour of vehicles is an important property for its relation to performance and safety. In 1970s, Pacejka did the groundwork for an objective analysis introducing the handling diagram and the understeer coefficient. In more recent years, the understeer concept is still mentioned but the handling is actively managed by direct yaw control (DYC). In this paper an accurate analysis of the vehicle handling is carried out, considering also the effect of drive forces. This analysis brings to a new formulation of the understeer coefficient, which is almost equivalent to the classical one, but it can be obtained by quasi-steady-state manoeuvres. In addition, it relates the vehicle yaw torque to the understeer coefficient, filling up the gap between the classical handling approach and DYC. A multibody model of a Formula SAE car is then used to perform quasi-steady-state simulations in order to verify the effectiveness of the new formulation. Some vehicle set-ups and wheel drive arrangements are simulated and the results are discussed. In particular, the handling behaviours of the rear wheel drive (RWD) and the front wheel drive (FWD) architectures are compared, finding an apparently surprising result: for the analysed vehicle the FWD is less understeering than for RWD. The relation between the yaw torque and the understeer coefficient allows to understand this behaviour and opens-up the possibility for different yaw control strategies.
Formulations and Branch-and-Cut Algorithms for the Generalized Vehicle Routing Problem
DEFF Research Database (Denmark)
Bektas, Tolga; Erdogan, Günes; Røpke, Stefan
2011-01-01
The Generalized Vehicle Routing Problem (GVRP) consists of nding a set of routes for a number of vehicles with limited capacities on a graph with the vertices partitioned into clusters with given demands such that the total cost of travel is minimized and all demands are met. This paper offers four...
Testing among functional forms: an extension of the Generalized Box-Cox formulation.
Oude Lansink, A.G.J.M.; Thijssen, G.
1998-01-01
This paper uses the Generalized Box - Cox framework and Double Length artificial Regression to test whether different specifications of the profit function are able to mimic the technology underlying panel data of Dutch arable farms for the period 1970 - 1988. To this end, a linear GBC is developed
Barbagallo, Annamaria; Di Meglio, Guglielmo; Mauro, Paolo
2017-07-01
The aim of the paper is to study, in a Hilbert space setting, a general random oligopolistic market equilibrium problem in presence of both production and demand excesses and to characterize the random Cournot-Nash equilibrium principle by means of a stochastic variational inequality. Some existence results are presented.
The Concept of General Relativity is not Related to Reality
Kotas, Ronald
2015-04-01
The concept of general relativity is not related to reality. It is not real or factual Science. GR cannot account for objects falling to earth or for the weight of objects sitting on the earth. The Cavendish demonstration showing the attraction between two masses at right angles to earth's gravity, is not explained by GR. No one can prove the existence of ``space fabric.'' The concept of ``space time'' effects causing gravitational attraction between masses is wrong. Conservation law of energy - momentum does not exist in GR. LIGO fails in detecting ``gravity waves'' because there is no ``space fabric'' to transmit them. The Gravity B Probe data manipulated to show some effects, is not proof of ``space fabric.'' It is Nuclear Quantum Gravitation that provides clear definitive explanation of Gravity and Gravitation. It is harmonious with Newtonian and Quantum Mechanics, and Scientific Logic. Nuclear Quantum Gravitation has 10 clear, Scientific proofs and 21 more good indications. With this theory the Physical Forces are Unified. See: OBSCURANTISM ON EINSTEIN GRAVITATION? http://www.santilli-foundation.org/inconsistencies-gravitation.php and Einstein's Theory of Relativity versus Classical Mechanics, by Paul Marmet http://www.newtonphysics.on.ca/einstein/
Energy Technology Data Exchange (ETDEWEB)
Benoist, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires
1959-07-01
The calculation of diffusion coefficients in a lattice necessitates the knowledge of a correct method of weighting the free paths of the different constituents. An unambiguous definition of this weighting method is given here, based on the calculation of leakages from a zone of a reactor. The formulation obtained, which is both simple and general, reduces the calculation of diffusion coefficients to that of collision probabilities in the different media; it reveals in the expression for the radial coefficient the series of the terms of angular correlation (cross terms) recently shown by several authors. This formulation is then used to calculate the practical case of a classical type of lattice composed of a moderator and a fuel element surrounded by an empty space. Analytical and numerical comparison of the expressions obtained with those inferred from the theory of BEHRENS shows up the importance of several new terms some of which are linked with the transparency of the fuel element. Cross terms up to the second order are evaluated. A practical formulary is given at the end of the paper. (author) [French] Le calcul des coefficients de diffusion dans un reseau suppose la connaissance d'un mode de ponderation correct des libres parcours des differents constituants. On definit ici sans ambiguite ce mode de ponderation a partir du calcul des fuites hors d'une zone de reacteur. La formulation obtenue, simple et generale, ramene le calcul des coefficients de diffusion a celui des probabilites de collision dans les differents milieux; elle fait apparaitre dans l'expression du coefficient radial la serie des termes de correlation angulaire (termes rectangles), mis en evidence recemment par plusieurs auteurs. Cette formulation est ensuite appliquee au calcul pratique d'un reseau classique, compose d'un moderateur et d'un element combustible entoure d'une cavite; la comparaison analytique et numerique des expressions obtenues avec celles deduites de la theorie de BEHRENS
Garrido-Balsells, José María; Jurado-Navas, Antonio; Paris, José Francisco; Castillo-Vazquez, Miguel; Puerta-Notario, Antonio
2015-03-09
In this paper, a novel and deeper physical interpretation on the recently published Málaga or ℳ statistical distribution is provided. This distribution, which is having a wide acceptance by the scientific community, models the optical irradiance scintillation induced by the atmospheric turbulence. Here, the analytical expressions previously published are modified in order to express them by a mixture of the known Generalized-K and discrete Binomial and Negative Binomial distributions. In particular, the probability density function (pdf) of the ℳ model is now obtained as a linear combination of these Generalized-K pdf, in which the coefficients depend directly on the parameters of the ℳ distribution. In this way, the Málaga model can be physically interpreted as a superposition of different optical sub-channels each of them described by the corresponding Generalized-K fading model and weighted by the ℳ dependent coefficients. The expressions here proposed are simpler than the equations of the original ℳ model and are validated by means of numerical simulations by generating ℳ -distributed random sequences and their associated histogram. This novel interpretation of the Málaga statistical distribution provides a valuable tool for analyzing the performance of atmospheric optical channels for every turbulence condition.
International Nuclear Information System (INIS)
Buchman, L.T.; Bardeen, J.M.
2005-01-01
A first order symmetric hyperbolic tetrad formulation of the Einstein equations developed by Estabrook and Wahlquist and put into a form suitable for numerical relativity by Buchman and Bardeen (the WEBB formulation) is adapted to explicit spherical symmetry and tested for accuracy and stability in the evolution of spherically symmetric black holes (the Schwarzschild geometry). The lapse and shift, which specify the evolution of the coordinates relative to the tetrad congruence, are reset at frequent time intervals to keep the constant-time hypersurfaces nearly orthogonal to the tetrad congruence and the spatial coordinate satisfying a kind of minimal rate of strain condition. By arranging through initial conditions that the constant-time hypersurfaces are asymptotically hyperbolic, we simplify the boundary value problem and improve stability of the evolution. Results are obtained for both tetrad gauges ('Nester' and 'Lorentz') of the WEBB formalism using finite difference numerical methods. We are able to obtain stable unconstrained evolution with the Nester gauge for certain initial conditions, but not with the Lorentz gauge
Low-frequency modes with high toroidal mode numbers. A general formulation
International Nuclear Information System (INIS)
Pegoraro, F.; Schep, T.J.
1979-09-01
Low-frequency waves with high toroidal mode numbers in an axisymmetric toroidal configuration are studied. In particular, the relationship between the periodicity constraints imposed by the geometry, magnetic shear and the spatial structure of eigenmodes is investigated. By exploiting the radial translational invariance and the poloidal periodicity of the gyrokinetic and Maxwell equations, the two-dimensional problem can be converted into a one-dimensional one and the mode structure can be expressed in terms of a single extended poloidal variable. This representation is used in the description of electromagnetic modes with phase velocities larger than the ion thermal velocity and with frequencies below the ion gyro-frequency. Trapped particle, curvature and compressional effects are retained. The dispersion equations for drift mode and Alfven-type modes are given in general geometry and simplified solutions are presented in the configuration of a double periodic plane slab. (Auth.)
The path integral formulation of fractional Brownian motion for the general Hurst exponent
International Nuclear Information System (INIS)
Calvo, I; Sanchez, R
2008-01-01
In 1995, Sebastian (1995 J. Phys. A: Math. Gen. 28 4305) gave a path integral computation of the propagator of subdiffusive fractional Brownian motion (fBm), i.e. fBm with a Hurst or self-similarity exponent H element of (0, 1/2). The extension of Sebastian's calculation to superdiffusion, H element of (1/2, 1], becomes however quite involved due to the appearance of additional boundary conditions on fractional derivatives of the path. In this communication, we address the construction of the path integral representation in a different fashion, which allows us to treat both subdiffusion and superdiffusion on an equal footing. The derivation of the propagator of fBm for the general Hurst exponent is then performed in a neat and unified way. (fast track communication)
Patients' Preferences Related to Benefits, Risks, and Formulations of Schizophrenia Treatment.
Levitan, Bennett; Markowitz, Michael; Mohamed, Ateesha F; Johnson, F Reed; Alphs, Larry; Citrome, Leslie; Bridges, John F P
2015-07-01
The objective of this study was to quantify patients' preferences related to benefits and risks of antipsychotic treatments for schizophrenia and to assess the relative importance of treatment attributes and adherence. Treatment-related preferences among U.S. residents with a self-reported physician diagnosis of schizophrenia were assessed via a discrete-choice experiment. Patients chose between competing hypothetical scenarios characterized by improvements in positive symptoms, negative symptoms, and social functioning; incidence of weight gain, extrapyramidal symptoms (EPS), hyperprolactinemia, and hyperglycemia; and medication formulation. Preferences were estimated by using a random-parameters logit model, and the impact of adherence was estimated with conditional logit models. The final sample consisted of 271 patients. Complete improvement in positive symptoms was the most preferred outcome (relative importance score of 10.0), followed by elimination of hyperglycemia (3.6, 95% confidence interval [CI]=2.6-4.6), improvement in negative symptoms (3.0, CI=1.6-4.3), reduced weight gain (2.6, CI=1.2-4.0), avoidance of hyperprolactinemia (1.7, CI=.9-2.6), improved social functioning (1.5, CI=.4-2.5), and avoidance of EPS (1.0, CI=.3-1.8). Patients judged a daily pill superior to monthly injections (p<.01) and monthly injections superior to injections every three months (p<.01) for adherent patients and monthly injections superior to a daily pill for nonadherent patients (p=.01). Persons who self-identified as having schizophrenia judged improvement in positive symptoms as the most important treatment benefit. Hyperglycemia was identified as the most important adverse event. Patients judged oral formulations to be better than monthly injections for adherent patients and monthly injections to be a better choice for nonadherent patients.
Preharvest Interval Periods and their relation to fruit growth stages and pesticide formulations.
Alister, Claudio; Araya, Manuel; Becerra, Kevin; Saavedra, Jorge; Kogan, Marcelo
2017-04-15
The aim of this study was to evaluate the effect of pesticide formulations and fruit growth stages on the Pre-harvest Interval Period (PHI). Results showed that pesticide formulations did not affect the initial deposit and dissipation rate. However, the fruit growth stage at the application time showed a significant effect on the above-mentioned parameters. Fruit diameter increases in one millimeter pesticide dissipation rates were reduced in -0.033mgkg -1 day -1 (R 2 =0.87; p<0.001) for grapes and -0.014mgkg -1 day -1 (R 2 =0.85; p<0.001) for apples. The relation between solar radiation, air humidity and temperature, and pesticide dissipation rates were dependent on fruit type. PHI could change according to the application time, because of the initial amount of pesticide deposit in the fruits and change in the dissipation rates. Because Maximum Residue Level are becoming more restrictive, it is more important to consider the fruit growth stage effects on pesticide when performing dissipation studies to define PHI. Copyright © 2016. Published by Elsevier Ltd.
Cosmological term in general relativity theory and localization of de Sitter and Einstein groups
International Nuclear Information System (INIS)
Tunyak, V.N.
1984-01-01
The theory of gauge gravitational field with the de Sitter group localization is formulated. proceeding from the de Sitter Universe tetrad components the relationship between Riemann metrics and de Sitter gauge field is established. It is shown that General relativity theory (GRT) with a cosmological term is the simplest variant of the de Sitter gauge gravitation theory passing in the limit of infinite curvature radius of the de Sitter Universe into the Poincare - invariant GRT without cosmological term. Similarly the theory of gauge gravitational field at localization of the dynamical group of the Einstein homogeneous static Universe (Einstein group RxSO(4)) is formulated
International Nuclear Information System (INIS)
Vilardy, Juan M; Millán, María S; Pérez-Cabré, Elisabet; Torres, Yezid
2014-01-01
We propose a generalization of the encryption system based on double random phase encoding (DRPE) and a joint transform correlator (JTC), from the Fourier domain to the fractional Fourier domain (FrFD) by using the fractional Fourier operators, such as the fractional Fourier transform (FrFT), fractional traslation, fractional convolution and fractional correlation. Image encryption systems based on a JTC architecture in the FrFD usually produce low quality decrypted images. In this work, we present two approaches to improve the quality of the decrypted images, which are based on nonlinear processing applied to the encrypted function (that contains the joint fractional power spectrum, JFPS) and the nonzero-order JTC in the FrFD. When the two approaches are combined, the quality of the decrypted image is higher. In addition to the advantages introduced by the implementation of the DRPE using a JTC, we demonstrate that the proposed encryption system in the FrFD preserves the shift-invariance property of the JTC-based encryption system in the Fourier domain, with respect to the lateral displacement of both the key random mask in the decryption process and the retrieval of the primary image. The feasibility of this encryption system is verified and analyzed by computer simulations. (paper)
The 'Falling Box' method in general relativity
International Nuclear Information System (INIS)
Gladush, V.D.
1998-01-01
The problems of justification, generalization, and applicability of the 'falling box' method to obtained some exact solutions of the vacuum Einstein equations are investigated. The 'physical' inference of the Reissner-Nordstrom-de Sitter and Kerr metrics is shown. Explanation is given for the well-known relativistic phenomenon which consists in that gravity is created by the double density of the electrical field energy
Hydrodynamics in full general relativity with conservative adaptive mesh refinement
East, William E.; Pretorius, Frans; Stephens, Branson C.
2012-06-01
There is great interest in numerical relativity simulations involving matter due to the likelihood that binary compact objects involving neutron stars will be detected by gravitational wave observatories in the coming years, as well as to the possibility that binary compact object mergers could explain short-duration gamma-ray bursts. We present a code designed for simulations of hydrodynamics coupled to the Einstein field equations targeted toward such applications. This code has recently been used to study eccentric mergers of black hole-neutron star binaries. We evolve the fluid conservatively using high-resolution shock-capturing methods, while the field equations are solved in the generalized-harmonic formulation with finite differences. In order to resolve the various scales that may arise, we use adaptive mesh refinement (AMR) with grid hierarchies based on truncation error estimates. A noteworthy feature of this code is the implementation of the flux correction algorithm of Berger and Colella to ensure that the conservative nature of fluid advection is respected across AMR boundaries. We present various tests to compare the performance of different limiters and flux calculation methods, as well as to demonstrate the utility of AMR flux corrections.
Directory of Open Access Journals (Sweden)
Ivelina Gueorguieva
2016-12-01
Full Text Available Objective: Galunisertib (LY2157299 monohydrate, an inhibitor of the transforming growth factor β (TGFβ pathway, is currently under investigation in several clinical trials involving multiple tumor types. The primary objective of this study was to assess relative bioavailability of two new galunisertib formulations developed using the roller compaction (RC dry-milled (RCD and RC slurry-milled (RCS processes, compared with the existing formulation developed using the high-sheer wet granulation (HSWG process. The secondary objective was to report the safety profile after a single dose of the three formulations. Methods: Patients with advanced or metastatic cancer were enrolled into this single-center, 3-period, 6-sequence crossover study. Patients were assigned sequentially to 1 of 6 sequences in blocks of 6 to ensure that all 6 sequences have the same number of completers. A patient entering a sequence received a different galunisertib formulation as a single 150 mg dose orally during each of the 3 periods. Each period was separated from the next by a washout interval of at least 48 hours. Pharmacokinetic (PK parameters, including area under curve (AUC and Cmax, were computed using standard non-compartmentalized methods of analysis. For comparison of exposures between formulations, log-transformed AUC and Cmax values were analyzed using a linear mixed-effects model. Safety assessments included adverse event monitoring, physical examinations, and laboratory tests. Results: Of the 14 patients who entered and completed the study, 13 patients were included in the final statistical analysis. AUC(0-tlast, AUC(0-48 h, and AUC(0-∞ for the RC formulations and the HSWG formulation were similar. Cmax was reduced by approximately 22% and tmax was longer by at least 1.00 h for the RCD and RCS formulations compared with the HSWG formulation. The RC formulations demonstrated a safety profile after a single dose similar to the HSWG formulation. Conclusions
General Information about AIDS-Related Lymphoma
... and treatment options. AIDS-related lymphoma is a disease in which malignant (cancer) cells form in the ... cord. The sample may also be checked for Epstein-Barr virus . This procedure is also called an LP ...
On ``minimally curved spacetimes'' in general relativity
Dadhich, Naresh
1997-01-01
We consider a spacetime corresponding to uniform relativistic potential analogus to Newtonian potential as an example of ``minimally curved spacetime''. We also consider a radially symmetric analogue of the Rindler spacetime of uniform proper acceleration relative to infinity.
Grand Canonical Ensembles in General Relativity
International Nuclear Information System (INIS)
Klein, David; Yang, Wei-Shih
2012-01-01
We develop a formalism for general relativistic, grand canonical ensembles in space-times with timelike Killing fields. Using that, we derive ideal gas laws, and show how they depend on the geometry of the particular space-times. A systematic method for calculating Newtonian limits is given for a class of these space-times, which is illustrated for Kerr space-time. In addition, we prove uniqueness of the infinite volume Gibbs measure, and absence of phase transitions for a class of interaction potentials in anti-de Sitter space.
On hypermomentum in general relativity. Pt.1
International Nuclear Information System (INIS)
Hehl, F.W.; Kerlick, G.D.; Heyde, P. von der
1976-01-01
In this series of notes, we introduce a new quantity into the theory of classical matter fields. Besides the usual energy-momentum tensor, we postulate the existence of a further dynamical attribute of matter, the 3rd rank tensor Δsup(ijk) of hypermomentum. Subsequently, a general relativistic field theory of energy-momentum and hypermomentum is outlined. In Part I we motivate the need for hypermomentum. We split it into spin angular momentum, the dilatation hypermomentum, and traceless proper hypermomentum and discuss their physical meanings and conservation laws. (orig.) [de
International Nuclear Information System (INIS)
Gift, D.A.; Harris, G.I.; Gard, J.W.; Alexander, G.P.; Potchen, E.J.
1983-01-01
A significant proportion of diagnostic medical procedures are used in response to public or private policy rather than in response to an individual patient-physician interaction. We have studied the system whereby such policies are developed and implemented in the case of employment-related chest and lumbar spine roentgenograms, which were found to account for about 11% of the total use of diagnostic radiographs in the state of Michigan. We observed that factors influencing formulation of policy are diverse and largely nonmedical, organizational policies developed in similar environments are often very dissimilar and are highly subject to external influence, and perceptions of policy success and examination utility are typically subjective and uncertain. It is concluded that considerable opportunity exists to enhance the efficacy of such radiographic examinations through leverage provided by their policy-driven nature
DEFF Research Database (Denmark)
Jørgensen, Bo Hoffmann
2003-01-01
This brief report expresses the basic equations of an incompressible flow model in a form which can be translated easily into the form used by a numerical solver. The application of tensor notation makes is possible to effectively address the issue ofnumerical robustness and stating the model...... equations on a general form which accommodate curvilinear coordinates. Strong conservation form is obtained by formulating the equations so that the flow variables, velocity and pressure, are expressed in thephysical coordinate system while the location of evaluation is expressed within the transformed...... form of the equations is included which allows for special solutions to be developed in the transformedcoordinate system. Examples of applications are atmospheric flows over complex terrain, aerodynamically flows, industrial flows and environmental flows....
Moriarty, John A.
1988-08-01
The first-principles, density-functional version of the generalized pseudopotential theory (GPT) developed in papers I and II of this series [Phys. Rev. B 16, 2537 (1977); 26, 1754 (1982)] for empty- and filled-d-band metals is here extended to pure transition metals with partially filled d bands. The present focus is on a rigorous, real-space expansion of the bulk total energy in terms of widely transferable, structure-independent interatomic potentials, including both central-force pair interactions and angular-force triplet and quadruplet interactions. To accomplish this expansion, a specialized set of starting equations is derived from the basic local-density formalism for a pure metal, including refined expansions for the exchange-correlation terms and a simplified yet accurate representation of the cohesive energy. The parent pseudo-Green's-function formalism of the GPT is then used to develop these equations in a plane-wave, localized-d-state basis. In this basis, the cohesive energy divides quite naturally into a large volume component and a smaller structural component. The volume component,which includes all one-ion intra-atomic energy contributions, already gives a good description of the cohesion in lowest order. The structural component is expanded in terms of weak interatomic matrix elements and gives rise to a multi-ion series which establishes the interatomic potentials. Special attention is focused on the dominant d-electron contributions to this series and complete formal results for the two-ion, three-ion, and four-ion d-state potentials (vd2, vd3, and vd4) are derived. In addition, a simplified model is used to demonstrate that while vd3 can be of comparable importance to vd2, vd4 is inherently small and the series is rapidly convergent beyond three-ion interactions. Analytic model forms are also derived for vd2 and vd3 in the case of canonical d bands. In this limit, vd2 is purely attractive and varies with interatomic distance as r-10, while
Energy Technology Data Exchange (ETDEWEB)
Kleinsmith, P E [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)
1976-04-01
Multiple spatial scaling is incorporated in a modified form of the Bogoliubov plasma cluster expansion; then this proposed reformulation of the plasma weak-coupling approximation is used to derive, from the BBGKY Hierarchy, a decoupled set of equations for the one-and two-particle distribution functions in the limit as the plasma parameter goes to zero. Because the reformulated cluster expansion permits retention of essential two-particle collisional information in the limiting equations, while simultaneously retaining the well-established Debye-scale relative ordering of the correlation functions, decoupling of the Hierarchy is accomplished without introduction of the divergence problems encountered in the Bogoliubov theory, as is indicated by an exact solution of the limiting equations for the equilibrium case. To establish additional links with existing plasma equilibrium theories, the two-particle equilibrium correlation function is used to calculate the interaction energy and the equation of state. The limiting equation for the equilibrium three-particle correlation function is then developed, and a formal solution is obtained.
Nonequilibrium statistical mechanics in the general theory of relativity. I. A general formalism
International Nuclear Information System (INIS)
Israel, W.; Kandrup, H.E.
1984-01-01
This is the first in a series of papers, the overall objective of which is the formulation of a new covariant approach to nonequilibrium statistical mechanics in classical general relativity. The objecct here is the development of a tractable theory for self-gravitating systems. It is argued that the ''state'' of an N-particle system may be characterized by an N-particle distribution function, defined in an 8N-dimensional phase space, which satisfies a collection of N conservation equations. By mapping the true physics onto a fictitious ''background'' spacetime, which may be chosen to satisfy some ''average'' field equations, one then obtains a useful covariant notion of ''evolution'' in response to a fluctuating ''gravitational force.'' For many cases of practical interest, one may suppose (i) that these fluctuating forces satisfy linear field equations and (ii) that they may be modeled by a direct interaction. In this case, one can use a relativistic projection operator formalism to derive exact closed equations for the evolution of such objects as an appropriately defined reduced one-particle distribution function. By capturing, in a natural way, the notion of a dilute gas, or impulse, approximation, one is then led to a comparatively simple equation for the one-particle distribution. If, furthermore, one treats the effects of the fluctuating forces as ''localized'' in space and time, one obtains a tractable kinetic equation which reduces, in the Newtonian limit, to the stardard Landau equation
Singularities in the general theory of relativity
International Nuclear Information System (INIS)
Treder, H.J.
1980-01-01
'Regular solutions of Einstein's equations' mean very different things. In the case of the empty-space equations, Rsub(ik) = o, such solutions must be metrics gsub(ik)(xsup(l)) without additionaly singular 'field sources' (Einstein's 'Particle problem'). However the 'phenomenological matter' is defined by the Einstein equations Rsub(ik) - 1/2gsub(ik)R = -kappaTsub(ik) itselves. Therefore if 10 regular functions gsub(ik)(xsup(l)) are given (which the inequalities of Lorentz-signature fulfil) then these gsub(ik) define 10 functions Tsub(ik)(xsup(l)) without singularities. But, the matter-tensor Tsub(ik) must fulfil the two inequalities T >= o, T 0 0 >= 1/2 T only and therefore the Einstein-equations with 'phenomenological matter' mean the two inequalities R >= o, R 0 0 <= o which are incompatible with a permanently regular metric with Lorentz-signature, generally. (author)
Matroidal Structure of Generalized Rough Sets Based on Tolerance Relations
Directory of Open Access Journals (Sweden)
Hui Li
2014-01-01
of the generalized rough set based on the tolerance relation. The matroid can also induce a new relation. We investigate the connection between the original tolerance relation and the induced relation.
Solaiman, Amanda; Suliman, Ammar Said; Shinde, Swapnil; Naz, Sidra; Elkordy, Amal Ali
2016-03-30
Despite the popularity of orally fast disintegrating tablets (FDTs), their formulation can sometimes be challenging, producing tablets with either poor mechanical properties or high disintegration times. The aim of this research was to enhance the properties of FDTs produced by direct compression to have both sufficient hardness to withstand manual handling, and rapid disintegration time. General multilevel factorial design was applied to optimise and evaluate main and interaction effects of independent variables (i) disintegrant concentration, (ii) % filler (Disintequick MCC-25) to mannitol on the responses hardness, tensile strength and disintegration time. In this experiment mannitol was used as a diluent, Disintequick MCC-25 (to best of our knowledge there is no publication available yet for its use with FDTs) was termed in this study as a filler and croscaremellose sodium was used as the superdisintegrant. Seven formulations were prepared following a progressive two-stage approach. Each stage involved the change in the ratio of excipients (Mannitol:Filler) (1:0), (1:0.25), (1:0.50), (1:1), (0.50:1), (0.25:1), (0:1) w/w and concentration of superdisintegrant (1%, 3%, 5%, 7%, 10% w/w). All FDTs were tested for different parameters such as diameter, hardness, tensile strength, thickness, friability and disintegration time. The results of multiple linear regression analysis show a good degree of correlation between experimental (R(2):0.84, 0.94, 0.91) and predicted response (R(2):0.83, 0.96, 0.95) for hardness, tensile strength and disintegration time respectively. The optimum formulations (regarding disintegration time with acceptable hardness and friability properties) consisted of: (i) 5% w/w disintegrant and 20% w/w filler to mannitol, showing a disintegration time of 30s, a hardness of 66.6N (6.8 kg/cm(2)) and friability of 2.2%; (ii) 7% or 10% w/w disintegrant with 33.33% w/w filler to mannitol, showing disintegration time of 84 s (for 7% disintegrant) and
International Nuclear Information System (INIS)
Hau, L.-N.; Lai, Y.-T.
2013-01-01
Harris-type current sheets with the magnetic field model of B-vector=B x (z)x-caret+B y (z)y-caret have many important applications to space, astrophysical, and laboratory plasmas for which the temperature or pressure usually exhibits the gyrotropic form of p↔=p ∥ b-caretb-caret+p ⊥ (I↔−b-caretb-caret). Here, p ∥ and p ⊥ are, respectively, to be the pressure component along and perpendicular to the local magnetic field, b-caret=B-vector/B. This study presents the general formulation for magnetohydrodynamic (MHD) wave propagation, fire-hose, and mirror instabilities in general Harris-type current sheets. The wave equations are expressed in terms of the four MHD characteristic speeds of fast, intermediate, slow, and cusp waves, and in the local (k ∥ ,k ⊥ ,z) coordinates. Here, k ∥ and k ⊥ are, respectively, to be the wave vector along and perpendicular to the local magnetic field. The parameter regimes for the existence of discrete and resonant modes are identified, which may become unstable at the local fire-hose and mirror instability thresholds. Numerical solutions for discrete eigenmodes are shown for stable and unstable cases. The results have important implications for the anomalous heating and stability of thin current sheets.
Large-scale tides in general relativity
Energy Technology Data Exchange (ETDEWEB)
Ip, Hiu Yan; Schmidt, Fabian, E-mail: iphys@mpa-garching.mpg.de, E-mail: fabians@mpa-garching.mpg.de [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany)
2017-02-01
Density perturbations in cosmology, i.e. spherically symmetric adiabatic perturbations of a Friedmann-Lemaȋtre-Robertson-Walker (FLRW) spacetime, are locally exactly equivalent to a different FLRW solution, as long as their wavelength is much larger than the sound horizon of all fluid components. This fact is known as the 'separate universe' paradigm. However, no such relation is known for anisotropic adiabatic perturbations, which correspond to an FLRW spacetime with large-scale tidal fields. Here, we provide a closed, fully relativistic set of evolutionary equations for the nonlinear evolution of such modes, based on the conformal Fermi (CFC) frame. We show explicitly that the tidal effects are encoded by the Weyl tensor, and are hence entirely different from an anisotropic Bianchi I spacetime, where the anisotropy is sourced by the Ricci tensor. In order to close the system, certain higher derivative terms have to be dropped. We show that this approximation is equivalent to the local tidal approximation of Hui and Bertschinger [1]. We also show that this very simple set of equations matches the exact evolution of the density field at second order, but fails at third and higher order. This provides a useful, easy-to-use framework for computing the fully relativistic growth of structure at second order.
Einstein's space-time an introduction to special and general relativity
Ferraro, Rafael
2007-01-01
Einstein's Space-Time: An Introduction to Special and General Relativity is a textbook addressed to students in physics and other people interested in Relativity and a history of physics. The book contains a complete account of Special Relativity that begins with the historical analysis of the reasons that led to a change in our manner of regarding the space and time. The first chapters are aimed to afford a deep understanding of the relativistic spacetime and its consequences for Dynamics. The chapter about covariant formulation includes among its topics the concepts of volume and hypersurfaces in manifolds, energy-momentum tensor of a fluid, and prepares the language for General Relativity. The last two chapters are devoted to an introduction of General Relativity and Cosmology in a modern approach connected with the latest discoveries in these areas.
General and special education teachers' relations within teamwork ...
African Journals Online (AJOL)
and instruction, assessment and evaluation, and classroom management and behavior. Typically, the ... teaching techniques and learning processes. ... general objective of this research is to establish the relations of general and special.
Liouville's equation and radiative acceleration in general relativity
International Nuclear Information System (INIS)
Keane, A.J.
1999-01-01
This thesis examines thoroughly the general motion of a material charged particle in the intense radiation field of a static spherically symmetric compact object with spherical emitting surface outside the Schwarzschild radius. Such a test particle will be pulled in by the gravitational attraction of the compact object and pushed out by the radiation pressure force, therefore the types of trajectory admitted will depend the gravitational field, the radiation field and the particle cross-section. The presence of a strong gravitational field demands a fully general relativistic treatment of the problem. This type of calculation is interesting not only as a formal problem in general relativity but also since it has important astrophysical implications, for example, application to astrophysical discs and jets. In chapter 1 we review the classical radiation force problem and outline the transition to a fully general relativistic scenario. We discuss the method for obtaining the radiation pressure force and calculating the particle trajectories. We review previous work in this area and outline the aims of the thesis. Then we consider some astrophysical applications and discuss how realistic our calculations are. In chapter 2 we give an introduction and overview of differential geometry as this is necessary for an accurate description of tensors on a curved manifold. Then we review the general theory of relativity and in particular obtain the Schwarzschild metric describing a static spherically symmetric vacuum spacetime. Chapter 3 deals with test particle motion through a curved spacetime. Liouville's equation describes the statistical distribution in phase space of a collection of test particles and is based upon a Hamiltonian formulation of the dynamical system - this material also relies heavily upon the concepts of differential geometry introduced in chapter 2. In particular we are interested in photon transport and find the general solutions for some symmetric
Current aspects of formulation efforts and pore lifetime related to microneedle treatment of skin.
Milewski, Mikolaj; Brogden, Nicole K; Stinchcomb, Audra L
2010-05-01
The efficacy of microneedles in the area of transdermal drug delivery is well documented. Multiple studies have shown that enhancement of skin permeation by means of the creation of microscopic pores in the stratum corneum can greatly improve the delivery rates of drugs. However, skin pretreatment with microneedles is not the only factor affecting drug transport rates. Other factors, including drug formulation and rate of micropore closure, are also important for optimizing delivery by this route. This review aims to highlight work that has been done in these areas, with an emphasis on drug formulation parameters that affect transdermal flux. This review creates an appreciation for the many factors affecting microneedle-enhanced delivery. Most results clearly indicate that microneedle skin pretreatment by itself may have different effects on drug transport depending on the formulation used, and formulation characteristics have different effects on the transport through untreated skin and microneedle-treated skin. Several formulation approaches are reported to optimize microneedle-enhanced drug delivery, including co-solvent use, vesicular, nanoparticulate and gel systems. In addition to well-established factors that affect microneedle-assisted delivery (geometry, type of microneedle, etc.), formulation and pore viability are also critical factors that must be considered.
Mills, Stacia; Xiao, Anna Q; Wolitzky-Taylor, Kate; Lim, Russell; Lu, Francis G
2017-04-01
The objective of this study was to assess whether a 1-hour didactic session on the DSM-5 Cultural Formulation Interview (CFI) improves the cultural competence of general psychiatry residents. The main hypothesis was that teaching adult psychiatry residents a 1-hour session on the CFI would improve cultural competence. The exploratory hypothesis was that trainees with more experience in cultural diversity would have a greater increase in cultural competency scores. Psychiatry residents at a metropolitan, county hospital completed demographics and preintervention questionnaires, were exposed to a 1-hour session on the CFI, and were given a postintervention questionnaire. The questionnaire was an adapted version of the validated Cultural Competence Assessment Tool . Paired samples t tests compared pre- to posttest change. Hierarchical linear regression assessed whether pretraining characteristics predicted posttest scores. The mean change of total pre- and posttest scores was significant ( p = .002), as was the mean change in subscales Nonverbal Communications ( p < .001) and Cultural Knowledge ( p = .002). Demographic characteristics did not predict higher posttest scores (when covarying for pretest scores). Psychiatry residents' cultural competence scores improved irrespective of previous experience in cultural diversity. More research is needed to further explore the implications of the improved scores in clinical practice.
DSR Theories, Conformal Group and Generalized Commutation Relation
International Nuclear Information System (INIS)
Leiva, Carlos
2006-01-01
In this paper the relationship of DSR theories and Conformal Group is reviewed. On the other hand, the relation between DSR Magueijo Smolin generators and generalized commutation relations is also shown
Generalized uncertainty relations and characteristic invariants for the multimode states
International Nuclear Information System (INIS)
Sudarshan, E.C.G.; Chiu, C.B.; Bhamathi, G.
1995-01-01
The close relationship between the zero-point energy, the uncertainty relation, coherent states, squeezed states, and correlated states for one mode is investigated. This group theoretic perspective of the problem enables the parametrization and identification of their multimode generalization. A simple and efficient method of determining the canonical structure of the generalized correlated states is presented. Implication of canonical commutation relations for correlations are not exhausted by the Heisenberg uncertainty relation, not even by the Schroedinger-Robertson uncertainty inequality, but there are relations in the multimode case that are the generalization of the Schroedinger-Robertson relation
Differential forms and the geometry of general relativity
Dray, Tevian
2015-01-01
Differential Forms and the Geometry of General Relativity provides readers with a coherent path to understanding relativity. Requiring little more than calculus and some linear algebra, it helps readers learn just enough differential geometry to grasp the basics of general relativity.The book contains two intertwined but distinct halves. Designed for advanced undergraduate or beginning graduate students in mathematics or physics, most of the text requires little more than familiarity with calculus and linear algebra. The first half presents an introduction to general relativity that describes
Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Schreier, Theresa M.; Mayer, Denise A.; Aloisi, Douglas B.; Eckert, Nathan L.
2015-01-01
The study was completed to evaluate the exposure-related effects of a biopesticide for dreissenid mussel (Dreissena polymorpha, zebra mussel and Dreissena rostriformis bugensis, quagga mussel) control on glochidia from unionid mussels endemic to the Great Lakes and Upper Mississippi River Basins. The commercially prepared biopesticide was either a spray-dried powder (SDP) or freeze-dried powder (FDP) formulation of Pseudomonas fluorescens, strain CL145A. Glochidia of the unionid mussel species Lampsilis cardium, Lampsilis siliquoidea,Lampsilis higginsii, Ligumia recta, Obovaria olivaria, and Actinonaias ligamentina were exposed to SDP-formulated P. fluorescens andLampsilis cardium and Megalonaias nervosa were exposed to FDP-formulated P. fluorescens.
Spacetime and Geometry: An Introduction to General Relativity
International Nuclear Information System (INIS)
Poisson, E
2005-01-01
The ever growing relevance of general relativity to astrophysics and cosmology continues to motivate the publication of new textbooks which put the theory in a fresh perspective informed by recent developments. While the 1970s were the decade of Weinberg and Misner et al and the 80s the decade of Schutz and Wald, this is clearly the decade of Hartle and Carroll. Hartle has introduced a novel pedagogical approach to teaching general relativity, which he convincingly argues should be done in the standard undergraduate physics curriculum. His 'physics-first approach' emphasizes physical phenomena and minimizes mathematical formalism. Hartle achieves a lot by introducing only the spacetime metric and the geodesic equation, which are the main tools needed to explore curved spacetime and extract physical consequences. To be sure, to explain how the metric is obtained in the first place does require a background of differential geometry and the formulation of the Einstein field equations. But in Hartle's book this material is wisely presented at a later stage, after an ample sampling of the physics of curved spacetime has motivated the need for the advanced mathematics. Carroll follows instead the traditional route, what Hartle calls the 'math-first approach', in which one introduces first the required mathematical formalism and only then derives the physical consequences. He is, of course, in good company, as this is the method followed in all existing textbooks (with Hartle's being the sole exception). Carroll's approach may not be original, but it is tried and true, and the result of Carroll's efforts is an excellent introduction to general relativity. The book covers the standard topics that would be found in virtually all textbooks (differential geometry, the field equations, linearized theory, black holes, and cosmology), but in addition it contains topics (such as quantum field theory in curved spacetime) which can rarely be found in introductory texts. All these
Energy Technology Data Exchange (ETDEWEB)
Droppo, James G.
2006-07-01
The Department of Homeland Security and others rely on results from atmospheric dispersion models for threat evaluation, event management, and post-event analyses. The ability to simulate dry deposition rates is a crucial part of our emergency preparedness capabilities. Deposited materials pose potential hazards from radioactive shine, inhalation, and ingestion pathways. A reliable characterization of these potential exposures is critical for management and mitigation of these hazards. A review of the current status of dry deposition formulations used in these atmospheric dispersion models was conducted. The formulations for dry deposition of particulate materials from am event such as a radiological attack involving a Radiological Detonation Device (RDD) is considered. The results of this effort are applicable to current emergency preparedness capabilities such as are deployed in the Interagency Modeling and Atmospheric Assessment Center (IMAAC), other similar national/regional emergency response systems, and standalone emergency response models. The review concludes that dry deposition formulations need to consider the full range of particle sizes including: 1) the accumulation mode range (0.1 to 1 micron diameter) and its minimum in deposition velocity, 2) smaller particles (less than .01 micron diameter) deposited mainly by molecular diffusion, 3) 10 to 50 micron diameter particles deposited mainly by impaction and gravitational settling, and 4) larger particles (greater than 100 micron diameter) deposited mainly by gravitational settling. The effects of the local turbulence intensity, particle characteristics, and surface element properties must also be addressed in the formulations. Specific areas for improvements in the dry deposition formulations are 1) capability of simulating near-field dry deposition patterns, 2) capability of addressing the full range of potential particle properties, 3) incorporation of particle surface retention/rebound processes, and
Constraints on stress-energy perturbations in general relativity
International Nuclear Information System (INIS)
Traschen, J.
1985-01-01
Conditions are found for the existence of integral constraints on stress-energy perturbations in general relativity. The integral constraints can be thought of as a general-relativistic generalization of the conservation of energy and momentum of matter perturbations in special relativity. The constraints are stated in terms of a vector field V, and the Robertson-Walker spacetimes are shown to have such constraint vectors. Although in general V is not a Killing vector, in a vacuum spacetime the constraint vectors are precisely the Killing vectors
6th International Conference on the History of General Relativity
Eisenstaedt, Jean; The Universe of General Relativity; GR 6
2005-01-01
This volume from the Einstein Studies Series is based largely on papers presented at the Sixth International Conference on the History of General Relativity, held in Amsterdam on June 26-29, 2002. These contributions from notable experts offer both new and historical insights on gravitation, general relativity, cosmology, unified field theory, and the history of science. Topics discussed include the prehistory of special relativity, early attempts at a relativistic theory of gravitation, the beginnings of general relativity, the problem of motion in the context of relativity, conservation laws, the axiomatization of relativity, classical and contemporary cosmology, gravitation and electromagnetism, quantum gravity, and relativity as seen through the eyes of the public and renowned relativists. Contributors: K. Brading; G. Gale; H.F.M. Goenner; J. Goldberg; S. Katzir; D. Kennefick; H. Kragh; C. Lehner; U. Majer; J. Mattingly; E.T. Newman; J.D. Norton; J. Renn; R. Rynasiewicz; J.M. Sánchez-Ron; T. Sauer; C. Sm...
DEFF Research Database (Denmark)
Nøhr-Jensen, Lene; Damkier, Per; Bidstrup, Tanja Busk
2006-01-01
OBJECTIVE: The aim of this study was to investigate the pharmacokinetics of loratadine and its active metabolite desloratadine after single-dose administration of loratadine as a conventional tablet, orally disintegrating tablet (smelt tablet) and a chewing gum formulation with and without...... of medicated chewing gum without collection of saliva and a 30-mg portion of medicated chewing gum with collection of saliva. Blood samples were taken at predefined sampling points 0-24 h after medication, and the plasma concentrations of loratadine and desloratadine were determined by high-performance liquid...... chromatography. Each study period was separated by a wash-out period of at least 7 days. RESULTS: The mean dose-corrected area under the plasma concentration-time curve extrapolated to infinity AUC(0-infinity) for the chewing gum formulation was statistically significantly increased compared to the tablet...
The consistency assessment of topological relations in cartographic generalization
Zheng, Chunyan; Guo, Qingsheng; Du, Xiaochu
2006-10-01
The field of research in the generalization assessment has been less studied than the generalization process itself, and it is very important to keep topological relation consistency for meeting generalization quality. This paper proposes a methodology to assess the quality of generalized map from topological relations consistency. Taking roads (including railway) and residential areas for examples, from the viewpoint of the spatial cognition, some issues about topological consistency in different map scales are analyzed. The statistic information about the inconsistent topological relations can be obtained by comparing the two matrices: one is the matrix for the topological relations in the generalized map; the other is the theoretical matrix for the topological relations that should be maintained after generalization. Based on the fuzzy set theory and the classification of map object types, the consistency evaluation model of topological relations is established. The paper proves the feasibility of the method through the example about how to evaluate the local topological relations between simple roads and residential area finally.
Generalized string theory mapping relations between gravity and gauge theory
International Nuclear Information System (INIS)
Bjerrum-Bohr, N.E.J.
2003-01-01
A previous study of the Kawai, Lewellen and Tye (KLT) relations between gravity and gauge theories, imposed by the relationship of closed and open strings, are here extended in the light of general relativity and Yang-Mills theory as effective field theories. We discuss the possibility of generalizing the traditional KLT mapping in this effective setting. A generalized mapping between the effective Lagrangians of gravity and Yang-Mills theory is presented, and the corresponding operator relations between gauge and gravity theories at the tree level are further explored. From this generalized mapping remarkable diagrammatic relations are found, linking diagrams in gravity and Yang-Mills theory, as well as diagrams in pure effective Yang-Mills theory. Also the possibility of a gravitational coupling to an antisymmetric field in the gravity scattering amplitude is considered, and shown to allow for mixed open-closed string solutions, i.e., closed heterotic strings
Can one tell Einstein's unimodular theory from Einstein's general relativity?
Alvarez, Enrique
2005-01-01
The so called unimodular theory of gravitation is compared with general relativity in the quadratic (Fierz-Pauli) regime, using a quite broad framework, and it is argued that quantum effects allow in principle to discriminate between both theories.
The role of Einstein's general relativity theory in today's physics
International Nuclear Information System (INIS)
Bicak, J.
The relationships are discussed of the general relativity theory to other fields of today's physics. Recent results are reported of studies into gravitational radiation, relativistic astrophysics, cosmology and the quantum theory. (Z.M.)
Generalized hypervirial and Blanchard's recurrence relations for radial matrix elements
International Nuclear Information System (INIS)
Dong Shihai; Chen Changyuan; Lozada-Cassou, M
2005-01-01
Based on the Hamiltonian identity, we propose a generalized expression of the second hypervirial for an arbitrary central potential wavefunction in arbitrary dimensions D. We demonstrate that the new proposed second hypervirial formula is very powerful in deriving the general Blanchard's and Kramers' recurrence relations among the radial matrix elements. As their useful and important applications, we derive all general Blanchard's and Kramers' recurrence relations and some identities for the Coulomb-like potential, harmonic oscillator and Kratzer oscillator. The recurrence relation and identity between the exponential functions and the powers of the radial function are established for the Morse potential. The corresponding general Blanchard's and Kramers' recurrence relations in 2D are also briefly studied
Using CAMAL for algebraic computations in general relativity
International Nuclear Information System (INIS)
Fitch, J.P.
1979-01-01
CAMAL is a collection of computer algebra systems developed in Cambridge, England for use mainly in theoretical physics. One of these was designed originally for general relativity calculations, although it is often used in other fields. In a recent paper Cohen, Leringe, and Sundblad compared six systems for algebraic computations applied to general relativity available in Stockholm. Here similar information for CAMAL is given and by using the same tests CAMAL is added to the comparison. (author)
Palatini wormholes and energy conditions from the prism of general relativity
Energy Technology Data Exchange (ETDEWEB)
Bejarano, Cecilia [Instituto de Astronomia y Fisica del Espacio (IAFE, CONICET-UBA), Buenos Aires (Argentina); Centro Mixto Universidad de Valencia-CSIC. Universidad de Valencia, Departamento de Fisica Teorica y IFIC, Valencia (Spain); Lobo, Francisco S.N.; Rubiera-Garcia, Diego [Faculdade de Ciencias da Universidade de Lisboa, Instituto de Astrofisica e Ciencias do Espaco, Lisbon (Portugal); Olmo, Gonzalo J. [Centro Mixto Universidad de Valencia-CSIC. Universidad de Valencia, Departamento de Fisica Teorica y IFIC, Valencia (Spain); Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, Paraiba (Brazil)
2017-11-15
Wormholes are hypothetical shortcuts in spacetime that in general relativity unavoidably violate all of the pointwise energy conditions. In this paper, we consider several wormhole spacetimes that, as opposed to the standard designer procedure frequently employed in the literature, arise directly from gravitational actions including additional terms resulting from contractions of the Ricci tensor with the metric, and which are formulated assuming independence between metric and connection (Palatini approach). We reinterpret such wormhole solutions under the prism of General Relativity and study the matter sources that thread them. We discuss the size of violation of the energy conditions in different cases and how this is related to the same spacetimes when viewed from the modified gravity side. (orig.)
Palatini wormholes and energy conditions from the prism of general relativity.
Bejarano, Cecilia; Lobo, Francisco S N; Olmo, Gonzalo J; Rubiera-Garcia, Diego
2017-01-01
Wormholes are hypothetical shortcuts in spacetime that in general relativity unavoidably violate all of the pointwise energy conditions. In this paper, we consider several wormhole spacetimes that, as opposed to the standard designer procedure frequently employed in the literature, arise directly from gravitational actions including additional terms resulting from contractions of the Ricci tensor with the metric, and which are formulated assuming independence between metric and connection (Palatini approach). We reinterpret such wormhole solutions under the prism of General Relativity and study the matter sources that thread them. We discuss the size of violation of the energy conditions in different cases and how this is related to the same spacetimes when viewed from the modified gravity side.
Charles, Alexandre; Ballard, Patrick
2016-08-01
The dynamics of mechanical systems with a finite number of degrees of freedom (discrete mechanical systems) is governed by the Lagrange equation which is a second-order differential equation on a Riemannian manifold (the configuration manifold). The handling of perfect (frictionless) unilateral constraints in this framework (that of Lagrange's analytical dynamics) was undertaken by Schatzman and Moreau at the beginning of the 1980s. A mathematically sound and consistent evolution problem was obtained, paving the road for many subsequent theoretical investigations. In this general evolution problem, the only reaction force which is involved is a generalized reaction force, consistently with the virtual power philosophy of Lagrange. Surprisingly, such a general formulation was never derived in the case of frictional unilateral multibody dynamics. Instead, the paradigm of the Coulomb law applying to reaction forces in the real world is generally invoked. So far, this paradigm has only enabled to obtain a consistent evolution problem in only some very few specific examples and to suggest numerical algorithms to produce computational examples (numerical modeling). In particular, it is not clear what is the evolution problem underlying the computational examples. Moreover, some of the few specific cases in which this paradigm enables to write down a precise evolution problem are known to show paradoxes: the Painlevé paradox (indeterminacy) and the Kane paradox (increase in kinetic energy due to friction). In this paper, we follow Lagrange's philosophy and formulate the frictional unilateral multibody dynamics in terms of the generalized reaction force and not in terms of the real-world reaction force. A general evolution problem that governs the dynamics is obtained for the first time. We prove that all the solutions are dissipative; that is, this new formulation is free of Kane paradox. We also prove that some indeterminacy of the Painlevé paradox is fixed in this
Spinor formalism and complex-vector formalism of general relativity
International Nuclear Information System (INIS)
Han-ying, G.; Yong-shi, W.; Gendao, L.
1974-01-01
In this paper, using E. Cartan's exterior calculus, we give the spinor form of the structure equations, which leads naturally to the Newman--Penrose equations. Furthermore, starting from the spinor spaces and the el (2C) algebra, we construct the general complex-vector formalism of general relativity. We find that both the Cahen--Debever--Defrise complex-vector formalism and that of Brans are its special cases. Thus, the spinor formalism and the complex-vector formalism of general relativity are unified on the basis of the uni-modular group SL(2C) and its Lie algebra
Implications of a positive cosmological constant for general relativity.
Ashtekar, Abhay
2017-10-01
Most of the literature on general relativity over the last century assumes that the cosmological constant [Formula: see text] is zero. However, by now independent observations have led to a consensus that the dynamics of the universe is best described by Einstein's equations with a small but positive [Formula: see text]. Interestingly, this requires a drastic revision of conceptual frameworks commonly used in general relativity, no matter how small [Formula: see text] is. We first explain why, and then summarize the current status of generalizations of these frameworks to include a positive [Formula: see text], focusing on gravitational waves.
The general class of the vacuum spherically symmetric equations of the general relativity theory
International Nuclear Information System (INIS)
Karbanovski, V. V.; Sorokin, O. M.; Nesterova, M. I.; Bolotnyaya, V. A.; Markov, V. N.; Kairov, T. V.; Lyash, A. A.; Tarasyuk, O. R.
2012-01-01
The system of the spherical-symmetric vacuum equations of the General Relativity Theory is considered. The general solution to a problem representing two classes of line elements with arbitrary functions g 00 and g 22 is obtained. The properties of the found solutions are analyzed.
Avoidance of singularity and global non-conservation of energy in general relativity
International Nuclear Information System (INIS)
Verma, M.M.
2009-06-01
We show that the singularity in the General Theory of Relativity (GTR) is the expression of a non-Machian feature. It can be avoided with a scale-invariant dynamical theory, a property lacking in GTR. It is further argued that the global non-conservation of energy in GTR also results from the lack of scale-invariance, and the field formulation presented by several authors can only partly resolve the problem. Assuming the global energy conservation, we propose a negative energy density component with a positive equation of state that can drive the late-time acceleration in the universe, while the positive component confines to smaller scales. (author)
Some Remarks on Space-Time Decompositions, and Degenerate Metrics, in General Relativity
Bengtsson, Ingemar
Space-time decomposition of the Hilbert-Palatini action, written in a form which admits degenerate metrics, is considered. Simple numerology shows why D = 3 and 4 are singled out as admitting a simple phase space. The canonical structure of the degenerate sector turns out to be awkward. However, the real degenerate metrics obtained as solutions are the same as those that occur in Ashtekar's formulation of complex general relativity. An exact solution of Ashtekar's equations, with degenerate metric, shows that the manifestly four-dimensional form of the action, and its 3 + 1 form, are not quite equivalent.
The Poincare group as the symmetry group of canonical general relativity
International Nuclear Information System (INIS)
Beig, R.; Murchadha, N. o
1986-01-01
This work reconsiders the formulation, due to Regge and Teitelboim, of the phase space approach to General Relativity in the asymptotically flat context, phrasing it in the language of symplectic geometry. The necessary boundary conditions at spatial infinity are spelled out in detail. Precise meaning is given to the statement that, as a result of these boundary conditions, the Poincare group acts as a symmetry group on the phase space of G.R. This situation is compared with the spi-picture of Ashtekar and Hansen, where a larger asymptotic symmetry group is obtained. (Author)
Nonlinear Supersymmetric General Relativity and Unity of Nature
Shima, Kazunari; Tsuda, Motomu
2008-01-01
The basic idea and some physical implications of nonlinear supersymmetric general relativity (NLSUSY GR) are discussed, which give new insights into the origin of mass and the mysterious relations between the cosmology and the low energy particle physics, e.g. the spontaneous SUSY breaking scale, the cosmological constant, the (dark) energy density of the universe and the neutrino mass.
Indefinite-metric quantum field theory of general relativity, 2
International Nuclear Information System (INIS)
Nakanishi, Noboru
1978-01-01
The canonical commutation relations are analyzed in detail in the manifestly covariant quantum field theory of general relativity proposed previously. It is explicitly proved that the BRS charge is indeed the generator of the BRS transformation both in the Landau gauge and in the non-Landau one. The equivalence between the field equations and the Heisenberg equations is confirmed. (author)
Peressini, Donatella; Braunstein, Dobrila; Page, John H; Strybulevych, Anatoliy; Lagazio, Corrado; Scanlon, Martin G
2017-06-01
The objective was to evaluate whether an ultrasonic reflectance technique has predictive capacity for breadmaking performance of doughs made under a wide range of formulation conditions. Two flours of contrasting dough strength augmented with different levels of ingredients (inulin, oil, emulsifier or salt) were used to produce different bread doughs with a wide range of properties. Breadmaking performance was evaluated by conventional large-strain rheological tests on the dough and by assessment of loaf quality. The ultrasound tests were performed with a broadband reflectance technique in the frequency range of 0.3-6 MHz. Principal component analysis showed that ultrasonic attenuation and phase velocity at frequencies between 0.3 and 3 MHz are good predictors for rheological and bread scoring characteristics. Ultrasonic parameters had predictive capacity for breadmaking performance for a wide range of dough formulations. Lower frequency attenuation coefficients correlated well with conventional quality indices of both the dough and the bread. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
Study of energy partitioning using a set of related explosive formulations
Lieber, Mark; Foster, Joseph C.; Stewart, D. Scott
2012-03-01
Condensed phase high explosives convert potential energy stored in the electro-magnetic field structure of complex molecules to high power output during the detonation process. Historically, the explosive design problem has focused on intramolecular energy storage. The molecules of interest are derived via molecular synthesis providing near stoichiometric balance on the physical scale of the molecule. This approach provides prompt reactions based on transport physics at the molecular scale. Modern material design has evolved to approaches that employ intermolecular ingredients to alter the spatial and temporal distribution of energy release. State of the art continuum methods have been used to study this approach to the materials design. Cheetah has been used to produce data for a set of fictitious explosive formulations based on C-4 to study the partitioning of the available energy between internal and kinetic energy in the detonation. The equation of state information from Cheetah has been used in ALE3D to develop an understanding of the relationship between variations in the formulation parameters and the internal energy cycle in the products.
Experimental tests of general relativity: recent progress and future directions
International Nuclear Information System (INIS)
Turyshev, S G
2009-01-01
Einstein's general theory of relativity is the standard theory of gravity, especially where the needs of astronomy, astrophysics, cosmology, and fundamental physics are concerned. As such, this theory is used for many practical purposes involving spacecraft navigation, geodesy, and time transfer. We review the foundations of general relativity, discuss recent progress in tests of relativistic gravity, and present motivations for the new generation of high-accuracy tests of new physics beyond general relativity. Space-based experiments in fundamental physics are presently capable of uniquely addressing important questions related to the fundamental laws of nature. We discuss the advances in our understanding of fundamental physics that are anticipated in the near future and evaluate the discovery potential of a number of recently proposed space-based gravitational experiments. (reviews of topical problems)
Proceedings of the fourth Marcel Grossmann meeting on general relativity
International Nuclear Information System (INIS)
Ruffini, R.
1986-01-01
The Marcel Grossmann meetings were conceived with the aim of reviewing recent advances in gravitation and general relativity with the major emphasis on their mathematical foundations and physical predictions. Their main objective is to elicit contributions which deepen our understanding of space-time structures as well as to review the status of experiments verifying Einstein's Theory of Gravitation. It has been demonstrated by the previous meetings that these sessions provide physicists from various countries who are involved in research on general relativity with a unique opportunity to exchange experiences and enhance co-operation in fields of common interest. The meeting was essentially divided into 3 sub-areas; interplay between elementary particle physics and cosmology and relativistic astrophysics, classical relativity, and experimental relativity. Among the topics covered were supergravity and superstrings, bar gravitational wave detectors, black holes, classical relativity, computer relativity, cosmology and inos, early cosmology, exact solutions, Kaluza Klein theories, relativistic self-gravitating systems and quantum gravity. (Auth.)
The generalized Crewther relation in QCD and its experimental consequences
International Nuclear Information System (INIS)
Brodsky, S.J.; Gabadadze, G.T.; Kataev, A.L.; Lu, H.J.
1995-12-01
We use the BLM scale-fixing prescription to derive a renormalization-scheme invariant relation between the coefficient function for the Bjorken sum rule for polarized deep inelastic scattering and the R-ratio for the e + e - annihilation cross section. This relation provides a generalization of the Crewther relation to non-conformally invariant gauge theories. The derived relations allow one to calculate unambiguously without renormalization scale or scheme ambiguity the effective charges of the polarized Bjorken and the Gross-Llewellen Smith sum rules from the experimental value for the effective charge associated with R-ratio. Present data are consistent with the generalized Crewther relations, but measurements at higher precision and energies will be needed to decisively test these fundamental relations in QCD. (orig.)
Math, Souvik; Horn, Roger; Jayaram, Vikram; Biswas, Sanjay Kumar
2007-04-15
Currently data obtained from surface force apparatus experiments are convoluted with the mechanical response of glue of unknown thickness, used to bond mica sheets to the substrates. This paper describes a formulation to precisely deconvolute out the forces between the mica sheets by determining the thickness of glue, knowing the mechanical properties of the glue. The formulation consists of a general solution based on the noniterative Hankel transform of the Laplace equation. The generality is achieved by treating all the layers except the one in contact as an effective lumped system consisting of a set of springs in series, where each spring represents a layer. The solution is validated by nanoindentation of trilayer systems consisting of layers with widely diverse mechanical properties, some differing from each other by three orders of magnitude. SFA experiments are done with carefully metered slabs of glue. The proposed method is validated by comparing the actual glue thicknesses with those determined using the present analysis.
Directory of Open Access Journals (Sweden)
Raul R. Ribeiro
2013-08-01
Full Text Available The increasing use of nanotechnologies in advanced therapies has allowed the observation of specific adverse reactions related to nanostructures. The toxicity of a novel liposome formulation of meglumine antimoniate in dogs with visceral leishmaniasis after single dose has been investigated. Groups of 12 animals received by the intravenous route a single dose of liposomal meglumine antimoniate (group I [GI], 6.5 mg Sb/kg, empty liposomes (GII or isotonic saline (GIII. Evaluation of hematological and biochemical parameters showed no significant changes 4 days after administration. No undesired effects were registered in the GIII. However, adverse reactions were observed in 67.7% of dogs from both groups that received liposomal formulations. The side effects began moments after bolus administration and disappeared during the first 15 minutes after treatment. Prostation, sialorrhea and defecation were the most frequent clinical signs, registered in 33.3% and 41.6 % of animals from the groups GI and GII, respectively. Tachypnea, mydriasis, miosis, vomiting and cyanosis were also registered in both groups. The adverse reactions observed in this study were attributed to the activation of the complement system by lipid vesicles in a phenomenon known as Complement Activation-Related Pseudoallergy (CARPA. The influence of the physical-chemical characteristics of liposomal formulation in the triggering of CARPA is discussed.
The motion of a charged particle in general relativity
International Nuclear Information System (INIS)
Ludvigsen, M.
1979-01-01
A new approach to the problem of the motion of a self-interacting massive charged particle in general relativity is presented. A charged Robinson-Trautman solution is used as a general relativistic model of such a particle. Such a solution is shown to generate a unique world line in its own H space, which is interpreted as the world line of the particle. Using the R-T dynamical relations, the equation of motion of the particle is derived, which, in the limiting case of zero curvature, is shown to be the same as the classical Lorentz-Dirac equation of motion. (author)
Gravitational radiation and the validity of general relativity
International Nuclear Information System (INIS)
Will, C.M.
2001-01-01
The regular observation of gravitational radiation by a world-wide network of resonant and laser-interferometric detectors will usher in a new form of astronomy. At the same time, it will provide new and interesting tests of general relativity. We review the current empirical status of general relativity, and discuss three areas in which direct observation of gravitational radiation could test the theory further: polarization of the waves, speed of the waves, and back-reaction of the waves on the evolution of the source. (author)
On the mathematical theory of classical fields and general relativity
Klainerman, S
1993-01-01
From the perspective of an analyst, like myself, the General Theory of Relativity provides an extrordinary rich and vastly virgin territory. It is the aim of my lecture to provide, ﬁrst, an account of those aspects of the theory which attract me most and second a perspective of what has been accomplished so far in that respect. In trying to state our main objectives it helps to view General Relativity in the broader context of Classical Field Theory. EinsteiniVacuum equations, or shortly E—V, is already sufﬁciently complicated. I will thus restrict my attention to them.
Essays in general relativity a Festschrift for Abraham Taub
Tipler, Frank J
1981-01-01
Essays in General Relativity: A Festschrift for Abraham Taub is collection of essays to honor Professor Abraham H. Taub on the occasion of his retirement from the mathematics faculty of the University of California at Berkeley. Relativistic hydrodynamics has always been a subject dear to Taub's heart. In fact, many basic results on special relativistic fluid flows are due to him, and he has been a major contributor to the study of fluid flows near shocks. The book contains 16 chapters and begins with a discussion of a geometrical approach to general relativity. This is followed by separate cha
Doppler frequency in interplanetary radar and general relativity
Mcvittie, G. C.
1972-01-01
The change of frequency of an interplanetary radar signal sent from the earth to another planet or to a space probe is worked out according to general relativity. The Schwarzschild spacetime is employed and its null geodesics control the motion of the signals. Exact Doppler frequency formulas are derived for one-way and two-way radar in terms of an arbitrary Schwarzschild radial coordinate. A reduction to the special relativity case is used to interpret the formulas in terms of the relative radial velocity of emitter and target. The general relativity corrections are worked out approximately for each of three possible Schwarzschild radial coordinates, and a numerical example is given. The amount of the correction is different according as one or the other of the Schwarzschild coordinates is identified with the radius vector deduced from classical celestial mechanics. The identification problem is discussed.
Kundoor, Vipra; Dalby, Richard N
2011-08-01
To systematically evaluate the effect of formulation- and administration-related variables on nasal spray deposition using a nasal cast. Deposition pattern was assessed by uniformly coating a transparent nose model with Sar-Gel®, which changes from white to purple on contact with water. Sprays were subsequently discharged into the cast, which was then digitally photographed. Images were quantified using Adobe® Photoshop. The effects of formulation viscosity (which influences droplet size), simulated administration techniques (head orientation, spray administration angle, spray nozzle insertion depth), spray pump design and metering volume on nasal deposition pattern were investigated. There was a significant decrease in the deposition area associated with sprays of increasing viscosity. This appeared to be mediated by an increase in droplet size and a narrowing of the spray plume. Administration techniques and nasal spray pump design also had a significant effect on the deposition pattern. This simple color-based method provides quantitative estimates of the effects that different formulation and administration variables may have on the nasal deposition area, and provides a rational basis on which manufacturers of nasal sprays can base their patient instructions or post approval changes when it is impractical to optimize these using a clinical study.
Cosmological perturbations in a family of deformations of general relativity
International Nuclear Information System (INIS)
Krasnov, Kirill; Shtanov, Yuri
2010-01-01
We study linear cosmological perturbations in a previously introduced family of deformations of general relativity characterized by the absence of new degrees of freedom. The homogeneous and isotropic background in this class of theories is unmodified and is described by the usual Friedmann equations. The theory of cosmological perturbations is modified and the relevant deformation parameter has the dimension of length. Gravitational perturbations of the scalar type can be described by a certain relativistic potential related to the matter perturbations just as in general relativity. A system of differential equations describing the evolution of this potential and of the stress-energy density perturbations is obtained. We find that the evolution of scalar perturbations proceeds with a modified effective time-dependent speed of sound, which, contrary to the case of general relativity, does not vanish even at the matter-dominated stage. In a broad range of values of the length parameter controlling the deformation, a specific transition from the regime of modified gravity to the regime of general relativity in the evolution of scalar perturbations takes place during the radiation domination. In this case, the resulting power spectrum of perturbations in radiation and dark matter is suppressed on the comoving spatial scales that enter the Hubble radius before this transition. We estimate the bounds on the deformation parameter for which this suppression does not lead to observable consequences. Evolution of scalar perturbations at the inflationary stage is modified but very slightly and the primordial spectrum generated during inflation is not noticeably different from the one obtained in general relativity
BOOK REVIEW: Partial Differential Equations in General Relativity
Halburd, Rodney G.
2008-11-01
Although many books on general relativity contain an overview of the relevant background material from differential geometry, very little attention is usually paid to background material from the theory of differential equations. This is understandable in a first course on relativity but it often limits the kinds of problems that can be studied rigorously. Einstein's field equations lie at the heart of general relativity. They are a system of partial differential equations (PDEs) relating the curvature of spacetime to properties of matter. A central part of most problems in general relativity is to extract information about solutions of these equations. Most standard texts achieve this by studying exact solutions or numerical and analytical approximations. In the book under review, Alan Rendall emphasises the role of rigorous qualitative methods in general relativity. There has long been a need for such a book, giving a broad overview of the relevant background from the theory of partial differential equations, and not just from differential geometry. It should be noted that the book also covers the basic theory of ordinary differential equations. Although there are many good books on the rigorous theory of PDEs, methods related to the Einstein equations deserve special attention, not only because of the complexity and importance of these equations, but because these equations do not fit into any of the standard classes of equations (elliptic, parabolic, hyperbolic) that one typically encounters in a course on PDEs. Even specifying exactly what ones means by a Cauchy problem in general relativity requires considerable care. The main problem here is that the manifold on which the solution is defined is determined by the solution itself. This means that one does not simply define data on a submanifold. Rendall's book gives a good overview of applications and results from the qualitative theory of PDEs to general relativity. It would be impossible to give detailed
Koppolu, Ramya
Nanomaterials have diversified applications based on the unique properties. These nanoparticles and functionalized nanocomposites have been studied in the health care filed. Nanoparticles are mostly used in sunscreens which are a part of human life. These sunscreens consist of titanium dioxide and zinc oxide nanoparticles. Due to the higher band crevices, they help the skin to protect from ultraviolet rays, for instance, ultraviolet B and ultraviolet A. A series of nanostructured zinc oxide nanoparticles were prepared by cost-effective chemical and bioinspired methods and variables were optimized. Highly stable and spherical zinc oxide nanoparticles were formulated by aloe vera ( Aloe barbadensis) plant extract and avocado (Persea americana Mill) fruit extract. The state-of-the-art instrumentation was used to characterize the morphology, elemental composition, and particle size distribution. X-ray diffraction data indicated highly crystalline and ultrafine nanoparticles were obtained from the colloidal methods. The X-ray photoelectron spectroscopy results showed the chemical state of zinc, carbon, and oxygen atoms were well-indexed and are used as fingerprint identification of the elements. Transmission electron microscopy images show the shape of particles were cubic and fiber shape contingent upon the protecting operators and heat treatment conditions. The toxicity studies of zinc oxide nanoparticles were found to cause an increase in nitric oxide, which is protecting against further oxidative stress and appears to be nontoxic.
General projective relativity and the vector-tensor gravitational field
International Nuclear Information System (INIS)
Arcidiacono, G.
1986-01-01
In the general projective relativity, the induced 4-dimensional metric is symmetric in three cases, and we obtain the vector-tensor, the scalar-tensor, and the scalar-vector-tensor theories of gravitation. In this work we examine the vector-tensor theory, similar to the Veblen's theory, but with a different physical interpretation
Test theories of special relativity: a general critique
International Nuclear Information System (INIS)
Maciel, A.K.A.; Tiomno, J.
1988-01-01
Absolute Spacetime Theories conceived for the purpose of testing Special Relativity (SR) are reviewed. It is found that most theories proposed were in fact SR in different coordinate systems, since in general no specific SR violations were introduced. Models based on possible SR violating mechanisms are considered. Misconceptions in recently published papers are examined. (author) [pt
An experiment designed to verify the general theory of relativity
International Nuclear Information System (INIS)
Surdin, Maurice
1960-01-01
The project for an experiment which uses the effect of gravitation on Maser-type clocks placed on the ground at two different heights and which is designed to verify the general theory of relativity. Reprint of a paper published in Comptes rendus des seances de l'Academie des Sciences, t. 250, p. 299-301, sitting of 11 January 1960 [fr
Albert Einstein's 1916 Review Article on General Relativity
Sauer, Tilman
2004-01-01
The first comprehensive overview of the final version of the general theory of relativity was published by Einstein in 1916 after several expositions of preliminary versions and latest revisions of the theory in November 1915. A historical account of this review paper is given, of its prehistory, including a discussion of Einstein's collaboration with Marcel Grossmann, and of its immediate reception.
Derivation of Einstein-Cartan theory from general relativity
Petti, Richard
2015-04-01
General relativity cannot describe exchange of classical intrinsic angular momentum and orbital angular momentum. Einstein-Cartan theory fixes this problem in the least invasive way. In the late 20th century, the consensus view was that Einstein-Cartan theory requires inclusion of torsion without adequate justification, it has no empirical support (though it doesn't conflict with any known evidence), it solves no important problem, and it complicates gravitational theory with no compensating benefit. In 1986 the author published a derivation of Einstein-Cartan theory from general relativity, with no additional assumptions or parameters. Starting without torsion, Poincaré symmetry, classical or quantum spin, or spinors, it derives torsion and its relation to spin from a continuum limit of general relativistic solutions. The present work makes the case that this computation, combined with supporting arguments, constitutes a derivation of Einstein-Cartan theory from general relativity, not just a plausibility argument. This paper adds more and simpler explanations, more computational details, correction of a factor of 2, discussion of limitations of the derivation, and discussion of some areas of gravitational research where Einstein-Cartan theory is relevant.
General relativity from a gauged Wess-Zumino-Witten term
International Nuclear Information System (INIS)
Anabalon, Andres; Willison, Steven; Zanelli, Jorge
2007-01-01
In this paper two things are done. First it is shown how a four-dimensional gauged Wess-Zumino-Witten term arises from the five-dimensional Einstein-Hilbert plus Gauss-Bonnet Lagrangian with a special choice of the coefficients. Second, the way in which the equations of motion of four-dimensional General Relativity arise is exhibited
Proceedings of the third Marcel Grossmann meeting on general relativity
International Nuclear Information System (INIS)
Hu Ning
1983-01-01
This book contains 64 session papers presented at the 3rd Marcel Grossmann Meeting on General Relativity. The papers are divided into 10 sections including: classical problem in gravitation; alternative approaches to gravitational theory; supergravity; quantum gravity and quantum field theory in curved space; cosmology; early universe; physics of compact bodies; gravitational wave experiments; gravitational experiments; miscellaneous. (Auth.)
Generalized virial relations and the theory of subdynamics
International Nuclear Information System (INIS)
Obcemea, Ch.; Froelich, P.; Braandas, E.J.
1981-05-01
In this paper, we discuss the implication of the generalized virial relations in the spectral analysis of Liouville operators. In particular, we refer to the existence problem of the analytic continuation of these super-operators and their resolvents occurring in the reduced dynamics description of open systems. For completeness, we outline the main ideas of the subdynamics approach. (author)
Energy-momentum distribution: A crucial problem in general relativity
Sharif, M.; Fatima, T.
2005-01-01
This paper is aimed to elaborate the problem of energy–momentum in general relativity. In this connection, we use the prescriptions of Einstein, Landau–Lifshitz, Papapetrou and Möller to compute the energy–momentum densities for two exact solutions of Einstein field equations. The space–times under
Statistical equilibrium and symplectic geometry in general relativity
International Nuclear Information System (INIS)
Iglesias, P.
1981-09-01
A geometrical construction is given of the statistical equilibrium states of a system of particles in the gravitational field in general relativity. By a method of localization variables, the expression of thermodynamic values is given and the compatibility of this description is shown with a macroscopic model of a relativistic continuous medium for a given value of the free-energy function [fr
Collineations of the curvature tensor in general relativity
Indian Academy of Sciences (India)
The general theory of relativity, which is a field theory of gravitation, is described by the Einstein field equations. These equations whose fundamental constituent is the space-time metric gij, are highly non-linear partial differential equations and, therefore it is very difficult to obtain exact solutions. They become still more diffi-.
The general theory of relativity: the first thirty years
International Nuclear Information System (INIS)
Chandrasekhar, S.
1980-01-01
The principal landmarks in the development of general relativity (exclusive of cosmology) during the first 30 years after its founding are presented. The emergence of the new gravitational laws, their experimental consequences and the consequent growth of the present concern with gravitational collapse and black holes are traced. (U.K.)
Scalar fields and cosmic censorship hypothesis in general relativity
International Nuclear Information System (INIS)
Parnovs'kij, S.L.; Gajdamaka, O.Z.
2004-01-01
We discuss an influence of the presence of some nonstandard scalar fields in the vicinity of naked time-like singularity on the type and properties of this singularity. The main goal is to study the validity of the Penrose's Cosmic Censorship hypothesis in the General Relativity
Probing Students' Understanding of Some Conceptual Themes in General Relativity
Bandyopadhyay, Atanu; Kumar, Arvind
2010-01-01
This work is an attempt to see how physics undergraduates view the basic ideas of general relativity when they are exposed to the topic in a standard introductory course. Since the subject is conceptually and technically difficult, we adopted a "case studies" approach, focusing in depth on about six students who had just finished a one semester…
Galileons as the Scalar Analogue of General Relativity
Klein, Remko; Ozkan, Mehmet; Roest, Diederik
2016-01-01
We establish a correspondence between general relativity with diffeomorphism invariance and scalar field theories with Galilean invariance: notions such as the Levi-Civita connection and the Riemann tensor have a Galilean counterpart. This suggests Galilean theories as the unique nontrivial
Hamiltonian formalism for perfect fluids in general relativity
International Nuclear Information System (INIS)
Demaret, J.; Moncrief, V.
1980-01-01
Schutz's Hamiltonian theory of a relativistic perfect fluid, based on the velocity-potential version of classical perfect fluid hydrodynamics as formulated by Seliger and Whitham, is used to derive, in the framework of the Arnowitt, Deser, and Misner (ADM) method, a general partially reduced Hamiltonian for relativistic systems filled with a perfect fluid. The time coordinate is chosen, as in Lund's treatment of collapsing balls of dust, as minus the only velocity potential different from zero in the case of an irrotational and isentropic fluid. A ''semi-Dirac'' method can be applied to quantize astrophysical and cosmological models in the framework of this partially reduced formalism. If one chooses Taub's adapted comoving coordinate system, it is possible to derive a fully reduced ADM Hamiltonian, which is equal to minus the total baryon number of the fluid, generalizing a result previously obtained by Moncrief in the more particular framework of Taub's variational principle, valid for self-gravitating barotropic relativistic perfect fluids. An unconstrained Hamiltonian density is then explicitly derived for a fluid obeying the equation of state p=(gamma-1)rho (1 < or = γ < or = 2), which can adequately describe the phases of very high density attained in a catastrophic collapse or during the early stages of the Universe. This Hamiltonian density, shown to be equivalent to Moncrief's in the particular case of an isentropic fluid, can be simplified for fluid-filled class-A diagonal Bianchi-type cosmological models and appears as a suitable starting point for the study of the canonical quantization of these models
On stability relative to vector elements of the orbit in general relativity motion
International Nuclear Information System (INIS)
Abdil'din, M.M.; Bejsenova, N.A.
2002-01-01
In this work a question of a new type of stability - stability relative to vector elements of the orbit is considered in general relativity mechanics in case of the Lenze-Thirring and two body rotation. (author)
Generalization of the test theory of relativity to noninertial frames
International Nuclear Information System (INIS)
Abolghasem, G.H.; Khajehpour, M.R.H.; Mansouri, R.
1988-08-01
We present a generalized test theory of special relativity, using a noninertial frame. Within the framework of the special theory of relativity the transport- and Einstein-synchronizations are equivalent on a rigidly rotating disk. But in any theory with a preferred frame such an equivalence does not hold. The time difference resulting from the two synchronization procedures is a measurable quantity within the reach of existing clock systems on the earth. The final result contains a term which depends on the angular velocity of the rotating system, and hence measures an absolute effect. This term is of crucial importance in our test theory of the special relativity. (author). 13 refs
Reformulation of the symmetries of first-order general relativity
Montesinos, Merced; González, Diego; Celada, Mariano; Díaz, Bogar
2017-10-01
We report a new internal gauge symmetry of the n-dimensional Palatini action with cosmological term (n>3 ) that is the generalization of three-dimensional local translations. This symmetry is obtained through the direct application of the converse of Noether’s second theorem on the theory under consideration. We show that diffeomorphisms can be expressed as linear combinations of it and local Lorentz transformations with field-dependent parameters up to terms involving the variational derivatives of the action. As a result, the new internal symmetry together with local Lorentz transformations can be adopted as the fundamental gauge symmetries of general relativity. Although their gauge algebra is open in general, it allows us to recover, without resorting to the equations of motion, the very well-known Lie algebra satisfied by translations and Lorentz transformations in three dimensions. We also report the analog of the new gauge symmetry for the Holst action with cosmological term, finding that it explicitly depends on the Immirzi parameter. The same result concerning its relation to diffeomorphisms and the open character of the gauge algebra also hold in this case. Finally, we consider the non-minimal coupling of a scalar field to gravity in n dimensions and establish that the new gauge symmetry is affected by this matter field. Our results indicate that general relativity in dimension greater than three can be thought of as a gauge theory.
Escape trajectories of solar sails and general relativity
Energy Technology Data Exchange (ETDEWEB)
Kezerashvili, Roman Ya. [Physics Department, New York City College of Technology, City University of New York, 300 Jay Street, Brooklyn, NY 11201 (United States); Graduate School and University Center, City University of New York, 365 Fifth Avenue, New York, NY 10016 (United States); Vazquez-Poritz, Justin F., E-mail: jvazquez-poritz@citytech.cuny.ed [Physics Department, New York City College of Technology, City University of New York, 300 Jay Street, Brooklyn, NY 11201 (United States); Graduate School and University Center, City University of New York, 365 Fifth Avenue, New York, NY 10016 (United States)
2009-11-16
General relativity can have a significant impact on the long-range escape trajectories of solar sails deployed near the sun. For example, spacetime curvature in the vicinity of the sun can cause a solar sail traveling from about 4 solar radii to 2550 AU to be deflected by on the order of a million kilometers, and should therefore be taken into account at the beginning of the mission. There are a number of smaller general relativistic effects, such as frame dragging due to the slow rotation of the sun which can cause a deflection of more than one thousand kilometers.
Escape trajectories of solar sails and general relativity
International Nuclear Information System (INIS)
Kezerashvili, Roman Ya.; Vazquez-Poritz, Justin F.
2009-01-01
General relativity can have a significant impact on the long-range escape trajectories of solar sails deployed near the sun. For example, spacetime curvature in the vicinity of the sun can cause a solar sail traveling from about 4 solar radii to 2550 AU to be deflected by on the order of a million kilometers, and should therefore be taken into account at the beginning of the mission. There are a number of smaller general relativistic effects, such as frame dragging due to the slow rotation of the sun which can cause a deflection of more than one thousand kilometers.
Comparison of Einstein-Boltzmann solvers for testing general relativity
Bellini, E.; Barreira, A.; Frusciante, N.; Hu, B.; Peirone, S.; Raveri, M.; Zumalacárregui, M.; Avilez-Lopez, A.; Ballardini, M.; Battye, R. A.; Bolliet, B.; Calabrese, E.; Dirian, Y.; Ferreira, P. G.; Finelli, F.; Huang, Z.; Ivanov, M. M.; Lesgourgues, J.; Li, B.; Lima, N. A.; Pace, F.; Paoletti, D.; Sawicki, I.; Silvestri, A.; Skordis, C.; Umiltà, C.; Vernizzi, F.
2018-01-01
We compare Einstein-Boltzmann solvers that include modifications to general relativity and find that, for a wide range of models and parameters, they agree to a high level of precision. We look at three general purpose codes that primarily model general scalar-tensor theories, three codes that model Jordan-Brans-Dicke (JBD) gravity, a code that models f (R ) gravity, a code that models covariant Galileons, a code that models Hořava-Lifschitz gravity, and two codes that model nonlocal models of gravity. Comparing predictions of the angular power spectrum of the cosmic microwave background and the power spectrum of dark matter for a suite of different models, we find agreement at the subpercent level. This means that this suite of Einstein-Boltzmann solvers is now sufficiently accurate for precision constraints on cosmological and gravitational parameters.
New ghost-free extensions of general relativity
International Nuclear Information System (INIS)
Mann, R.B.
1989-01-01
The method of algebraic extension is shown to yield a large class of gravitational theories which are extensions of general relativity. Requiring positivity of energy in the flat-space limit of such theories provides some constraints, but a large set of theories of potential phenomenological interest survives this condition. Explicit examples of such theories include the non-symmetric gravitational theory, algebraically extended Hilbert gravity and a one-parameter family of theories with dynamical torsion. In general such theories do not alter general relativistic post-Newtonian predictions for time delay experiments; rather they alter the non-linearities of the post-Newtonian gravitational potential. Such effects may be probed by measuring periastron shifts, as in the eclipsing binary systems Di Her and As Cam, as well as in the binary pulsar PSR 1913 + 16 (author)
International Nuclear Information System (INIS)
Kates, R.E.
1979-01-01
This thesis shows that a small body with possibly strong internal gravity moves through an empty region of a curved, and not necessarily asymptotically flat, external spacetime on an approximate geodesic. By approximate geodesic, the following is meant: Suppose the ratio epsilon = m/L 1 - where m is the body's mass and L is a curvature reference length of the external field - is a small parameter. Then the body's worldline deviates from a geodesic only by distances of at most THETA(epsilon) L over times of order L. The worldline is calculated directly from the Einstein field equation using a singular perturbation technique that has been generalized from the method of matched asymptotic expansions. The need for singular perturbation techniques has long been appreciated in fluid mechanics, where they are now standard procedure in problems in which the straightforward expansion in powers of a small parameter fails to give a correct qualitative picture. In part I of this thesis, singular perturbations on manifolds are formulated in a coordinate-free way suitable for treating problems in general relativity and other field theories. Most importantly for this thesis, the coordinate-free formulation of singular perturbations given in part I is essential for treatment of the problem of motion in part II
Physical state condition in quantum general relativity as a consequence of BRST symmetry
International Nuclear Information System (INIS)
Castellana, Michele; Montani, Giovanni
2008-01-01
Quantization of systems with constraints can be carried out with several methods. In the Dirac formulation the classical generators of gauge transformations are required to annihilate physical quantum states to ensure their gauge invariance. Carrying on BRST symmetry it is possible to get a condition on physical states which, different from the Dirac method, requires them to be invariant under the BRST transformation. Employing this method for the action of general relativity expressed in terms of the spin connection and tetrad fields with path integral methods, we construct the generator of the BRST transformation associated with the underlying local Lorentz symmetry of the theory and write a physical state condition following from BRST invariance. This derivation is based on the general results on the dependence of the effective action used in path integrals and consequently of Green's functions on the gauge-fixing functionals used in the DeWitt-Faddeev-Popov method. The condition we gain differs from the one obtained within Ashtekar's canonical formulation, showing how we recover the latter only by a suitable choice of the gauge-fixing functionals. Finally we discuss how it should be possible to obtain all of the requested physical state conditions associated with all the underlying gauge symmetries of the classical theory using our approach
Isotropic extensions of the vacuum solutions in general relativity
Energy Technology Data Exchange (ETDEWEB)
Molina, C. [Universidade de Sao Paulo (USP), SP (Brazil); Martin-Moruno, Prado [Victoria University of Wellington (New Zealand); Gonzalez-Diaz, Pedro F. [Consejo Superior de Investigaciones Cientificas, Madrid (Spain)
2012-07-01
Full text: Spacetimes described by spherically symmetric solutions of Einstein's equations are of paramount importance both in astrophysical applications and theoretical considerations. And among those, black holes are highlighted. In vacuum, Birkhoff's theorem and its generalizations to non-asymptotically flat cases uniquely fix the metric as the Schwarzschild, Schwarzschild-de Sitter or Schwarzschild-anti-de Sitter geometries, the vacuum solutions of the usual general relativity with zero, positive or negative values for the cosmological constant, respectively. In this work we are mainly interested in black holes in a cosmological environment. Of the two main assumptions of the cosmological principle, homogeneity is lost when compact objects are considered. Nevertheless isotropy is still possible, and we enforce this condition. Within this context, we investigate spatially isotropic solutions close - continuously deformable - to the usual vacuum solutions. We obtain isotropic extensions of the usual spherically symmetric vacuum geometries in general relativity. Exact and perturbative solutions are derived. Maximal extensions are constructed and their causal structures are discussed. The classes of geometries obtained include black holes in compact and non-compact universes, wormholes in the interior region of cosmological horizons, and anti-de Sitter geometries with excess/deficit solid angle. The tools developed here are applicable in more general contexts, with extensions subjected to other constraints. (author)
Noncommutative unification of general relativity and quantum mechanics
International Nuclear Information System (INIS)
Heller, Michael; Pysiak, Leszek; Sasin, Wieslaw
2005-01-01
We present a model unifying general relativity and quantum mechanics based on a noncommutative geometry. This geometry is developed in terms of a noncommutative algebra A which is defined on a transformation groupoid Γ given by the action of a noncompact group G on the total space E of a principal fiber bundle over space-time M. The case is important since to obtain physical effects predicted by the model we should assume that G is a Lorentz group or some of its representations. We show that the generalized Einstein equation of the model has the form of the eigenvalue equation for the generalized Ricci operator, and all relevant operators in the quantum sector of the model are random operators; we study their dynamics. We also show that the model correctly reproduces general relativity and the usual quantum mechanics. It is interesting that the latter is recovered by performing the measurement of any observable. In the act of such a measurement the model 'collapses' to the usual quantum mechanics
On nomenclature for, and the relative merits of, two formulations of skew distributions
Azzalini, Adelchi
2015-12-21
We examine some skew distributions used extensively within the model-based clustering literature in recent years, paying special attention to claims that have been made about their relative efficacy. Theoretical arguments are provided as well as real data examples.
On nomenclature for, and the relative merits of, two formulations of skew distributions
Azzalini, Adelchi; Browne, Ryan P.; Genton, Marc G.; McNicholas, Paul D.
2015-01-01
We examine some skew distributions used extensively within the model-based clustering literature in recent years, paying special attention to claims that have been made about their relative efficacy. Theoretical arguments are provided as well as real data examples.
General Theory of Relativity: Will It Survive the Next Decade?
Bertolami, Orfeu; Paramos, Jorge; Turyshev, Slava G.
2006-01-01
The nature of gravity is fundamental to our understanding of our own solar system, the galaxy and the structure and evolution of the Universe. Einstein's general theory of relativity is the standard model that is used for almost ninety years to describe gravitational phenomena on these various scales. We review the foundations of general relativity, discuss the recent progress in the tests of relativistic gravity, and present motivations for high-accuracy gravitational experiments in space. We also summarize the science objectives and technology needs for the laboratory experiments in space with laboratory being the entire solar system. We discuss the advances in our understanding of fundamental physics anticipated in the near future and evaluate discovery potential for the recently proposed gravitational experiments.
Academic Training: Einstein and beyond: Introduction to General relativity
Françoise Benz
2005-01-01
2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 3, 4, 5, 6, 7 October from 11:00 to 12:00 - Main Auditorium, bldg. 500 Einstein and beyond: Introduction to General relativity by N. Straumann / Institut fur theoretische physics, Univ. Zürich We review the enduring achievements of Einstein's papers of 1905 and their impact on the further developments in physics. Program : Lectures I and II:Einstein's Contributions to Statistical Mechanics and Quantum Theory Lecture III:Einstein's Thesis at the University of Zürich Lecture IV: From Special to General Relativity Lecture V: The History and the Mystery of the Cosmological Constant ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch
Relations between task delegation and job satisfaction in general practice
DEFF Research Database (Denmark)
Riisgaard, Helle; Nexøe, Jørgen; Videbæk Le, Jette
2016-01-01
practitioners' and their staff's job satisfaction appears to be sparse even though job satisfaction is acknowledged as an important factor associated with both patient satisfaction and medical quality of care. Therefore, the overall aim of this study was 1) to review the current research on the relation between...... task delegation and general practitioners' and their staff's job satisfaction and, additionally, 2) to review the evidence of possible explanations for this relation. METHODS: A systematic literature review. We searched the four databases PubMed, Cinahl, Embase, and Scopus systematically. The immediate...... attitude towards task delegation was positive and led to increased job satisfaction, probably because task delegation comprised a high degree of work autonomy. CONCLUSIONS: The few studies included in our review suggest that task delegation within general practice may be seen by the staff as an overall...
Testing General Relativity with the Shadow Size of Sgr A(*).
Johannsen, Tim; Broderick, Avery E; Plewa, Philipp M; Chatzopoulos, Sotiris; Doeleman, Sheperd S; Eisenhauer, Frank; Fish, Vincent L; Genzel, Reinhard; Gerhard, Ortwin; Johnson, Michael D
2016-01-22
In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size may also depend strongly on parametric deviations from the Kerr metric. Based on a reconstructed image of Sagittarius A^{*} (Sgr A^{*}) from a simulated one-day observing run of a seven-station Event Horizon Telescope (EHT) array, we employ a Markov chain Monte Carlo algorithm to demonstrate that such an observation can measure the angular radius of the shadow of Sgr A^{*} with an uncertainty of ∼1.5 μas (6%). We show that existing mass and distance measurements can be improved significantly when combined with upcoming EHT measurements of the shadow size and that tight constraints on potential deviations from the Kerr metric can be obtained.
A century of general relativity: astrophysics and cosmology.
Blandford, R D
2015-03-06
One hundred years after its birth, general relativity has become a highly successful physical theory in the sense that it has passed a large number of experimental and observational tests and finds extensive application to a wide variety of cosmic phenomena. It remains an active area of research as new tests are on the way, epitomized by the exciting prospect of detecting gravitational waves from merging black holes. General relativity is the essential foundation of the standard model of cosmology and underlies our description of the black holes and neutron stars that are ultimately responsible for the most powerful and dramatic cosmic sources. Its interface with physics on the smallest and largest scales will continue to provide fertile areas of investigation in its next century. Copyright © 2015, American Association for the Advancement of Science.
A student's manual for A first course in general relativity
Scott, Robert B
2016-01-01
This comprehensive student manual has been designed to accompany the leading textbook by Bernard Schutz, A First Course in General Relativity, and uses detailed solutions, cross-referenced to several introductory and more advanced textbooks, to enable self-learners, undergraduates and postgraduates to master general relativity through problem solving. The perfect accompaniment to Schutz's textbook, this manual guides the reader step-by-step through over 200 exercises, with clear easy-to-follow derivations. It provides detailed solutions to almost half of Schutz's exercises, and includes 125 brand new supplementary problems that address the subtle points of each chapter. It includes a comprehensive index and collects useful mathematical results, such as transformation matrices and Christoffel symbols for commonly studied spacetimes, in an appendix. Supported by an online table categorising exercises, a Maple worksheet and an instructors' manual, this text provides an invaluable resource for all students and in...
A theory of strong interactions ''from'' general relativity
International Nuclear Information System (INIS)
Caldirola, P.; Recami, E.
1979-01-01
In this paper a previous letter (where, among other things, a classical ''quark confinement'' was derived from general relativity plus dilatation-covariance), is completed by showing that the theory is compatible also with quarks ''asymptotic freedom''. Then -within a bi-scale theory of gravitational and strong interactions- a classical field theory is proposed for the (strong) interactions between hadrons. Various consequences are briefly analysed
On the geometry of null congruences in general relativity
International Nuclear Information System (INIS)
Ahsan, Zafar; Malik, N.P.
1977-01-01
Some theorems for the null congruences within the framework of general theory of relativity are given. These theorems are important in themselves as they illustrate the geometric meaning of the spin coefficients. The newly developed Geroch-Held-Penrose (GHP) formalism has been used throughout the investigations. The salient features of GHP formalism that are necessary for the present work are given and these techniques are applied to a pair of null congruences C(l) and C(n). (author)
Testing general relativity at cosmological scales: Implementation and parameter correlations
International Nuclear Information System (INIS)
Dossett, Jason N.; Ishak, Mustapha; Moldenhauer, Jacob
2011-01-01
The testing of general relativity at cosmological scales has become a possible and timely endeavor that is not only motivated by the pressing question of cosmic acceleration but also by the proposals of some extensions to general relativity that would manifest themselves at large scales of distance. We analyze here correlations between modified gravity growth parameters and some core cosmological parameters using the latest cosmological data sets including the refined Cosmic Evolution Survey 3D weak lensing. We provide the parametrized modified growth equations and their evolution. We implement known functional and binning approaches, and propose a new hybrid approach to evolve the modified gravity parameters in redshift (time) and scale. The hybrid parametrization combines a binned redshift dependence and a smooth evolution in scale avoiding a jump in the matter power spectrum. The formalism developed to test the consistency of current and future data with general relativity is implemented in a package that we make publicly available and call ISiTGR (Integrated Software in Testing General Relativity), an integrated set of modified modules for the publicly available packages CosmoMC and CAMB, including a modified version of the integrated Sachs-Wolfe-galaxy cross correlation module of Ho et al. and a new weak-lensing likelihood module for the refined Hubble Space Telescope Cosmic Evolution Survey weak gravitational lensing tomography data. We obtain parameter constraints and correlation coefficients finding that modified gravity parameters are significantly correlated with σ 8 and mildly correlated with Ω m , for all evolution methods. The degeneracies between σ 8 and modified gravity parameters are found to be substantial for the functional form and also for some specific bins in the hybrid and binned methods indicating that these degeneracies will need to be taken into consideration when using future high precision data.
Canonical perturbation theory in linearized general relativity theory
International Nuclear Information System (INIS)
Gonzales, R.; Pavlenko, Yu.G.
1986-01-01
Canonical perturbation theory in linearized general relativity theory is developed. It is shown that the evolution of arbitrary dynamic value, conditioned by the interaction of particles, gravitation and electromagnetic fields, can be presented in the form of a series, each member of it corresponding to the contribution of certain spontaneous or induced process. The main concepts of the approach are presented in the approximation of a weak gravitational field
The role of general relativity in the uncertainty principle
International Nuclear Information System (INIS)
Padmanabhan, T.
1986-01-01
The role played by general relativity in quantum mechanics (especially as regards the uncertainty principle) is investigated. It is confirmed that the validity of time-energy uncertainty does depend on gravitational time dilation. It is also shown that there exists an intrinsic lower bound to the accuracy with which acceleration due to gravity can be measured. The motion of equivalence principle in quantum mechanics is clarified. (author)
Introduction to General Relativity and Black Holes (5/5)
CERN. Geneva
2001-01-01
Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.
Introduction to General Relativity and Black Holes (3/5)
CERN. Geneva
2001-01-01
Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.
Introduction to General Relativity and Black Holes (1/5)
CERN. Geneva
2001-01-01
Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.
Introduction to General Relativity and Black Holes (2/5)
CERN. Geneva
2001-01-01
Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.
Introduction to General Relativity and Black Holes (4/5)
CERN. Geneva
2001-01-01
Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.
New relativistic generalization of the Heisenberg commutation relations
International Nuclear Information System (INIS)
Bohm, A.; Loewe, M.; Magnollay, P.; Tarlini, M.; Aldinger, R.R.; Kielanowski, P.
1984-01-01
A relativistic generalization of the Heisenberg commutation relations is suggested which is different from the conventional ones used for the intrinsic coordinates and momenta in the relativistic oscillator model and the relativistic string. This new quantum relativistic oscillator model is determined by the requirement that it gives a unified description of relativistic vibrations and rotations and contracts in the nonrelativistic limit c -1 →0 into the usual nonrelativistic harmonic oscillator
Generalization of uncertainty relation for quantum and stochastic systems
Koide, T.; Kodama, T.
2018-06-01
The generalized uncertainty relation applicable to quantum and stochastic systems is derived within the stochastic variational method. This relation not only reproduces the well-known inequality in quantum mechanics but also is applicable to the Gross-Pitaevskii equation and the Navier-Stokes-Fourier equation, showing that the finite minimum uncertainty between the position and the momentum is not an inherent property of quantum mechanics but a common feature of stochastic systems. We further discuss the possible implication of the present study in discussing the application of the hydrodynamic picture to microscopic systems, like relativistic heavy-ion collisions.
Tests of general relativity from timing the double pulsar.
Kramer, M; Stairs, I H; Manchester, R N; McLaughlin, M A; Lyne, A G; Ferdman, R D; Burgay, M; Lorimer, D R; Possenti, A; D'Amico, N; Sarkissian, J M; Hobbs, G B; Reynolds, J E; Freire, P C C; Camilo, F
2006-10-06
The double pulsar system PSR J0737-3039A/B is unique in that both neutron stars are detectable as radio pulsars. They are also known to have much higher mean orbital velocities and accelerations than those of other binary pulsars. The system is therefore a good candidate for testing Einstein's theory of general relativity and alternative theories of gravity in the strong-field regime. We report on precision timing observations taken over the 2.5 years since its discovery and present four independent strong-field tests of general relativity. These tests use the theory-independent mass ratio of the two stars. By measuring relativistic corrections to the Keplerian description of the orbital motion, we find that the "post-Keplerian" parameter s agrees with the value predicted by general relativity within an uncertainty of 0.05%, the most precise test yet obtained. We also show that the transverse velocity of the system's center of mass is extremely small. Combined with the system's location near the Sun, this result suggests that future tests of gravitational theories with the double pulsar will supersede the best current solar system tests. It also implies that the second-born pulsar may not have formed through the core collapse of a helium star, as is usually assumed.
Explanatory and illustrative visualization of special and general relativity.
Weiskopf, Daniel; Borchers, Marc; Ertl, Thomas; Falk, Martin; Fechtig, Oliver; Frank, Regine; Grave, Frank; King, Andreas; Kraus, Ute; Müller, Thomas; Nollert, Hans-Peter; Rica Mendez, Isabel; Ruder, Hanns; Schafhitzel, Tobias; Schär, Sonja; Zahn, Corvin; Zatloukal, Michael
2006-01-01
This paper describes methods for explanatory and illustrative visualizations used to communicate aspects of Einstein's theories of special and general relativity, their geometric structure, and of the related fields of cosmology and astrophysics. Our illustrations target a general audience of laypersons interested in relativity. We discuss visualization strategies, motivated by physics education and the didactics of mathematics, and describe what kind of visualization methods have proven to be useful for different types of media, such as still images in popular science magazines, film contributions to TV shows, oral presentations, or interactive museum installations. Our primary approach is to adopt an egocentric point of view: The recipients of a visualization participate in a visually enriched thought experiment that allows them to experience or explore a relativistic scenario. In addition, we often combine egocentric visualizations with more abstract illustrations based on an outside view in order to provide several presentations of the same phenomenon. Although our visualization tools often build upon existing methods and implementations, the underlying techniques have been improved by several novel technical contributions like image-based special relativistic rendering on GPUs, special relativistic 4D ray tracing for accelerating scene objects, an extension of general relativistic ray tracing to manifolds described by multiple charts, GPU-based interactive visualization of gravitational light deflection, as well as planetary terrain rendering. The usefulness and effectiveness of our visualizations are demonstrated by reporting on experiences with, and feedback from, recipients of visualizations and collaborators.
International Nuclear Information System (INIS)
Sakazaki, L.E.; Talman, R.M.
1983-01-01
Though all existing strong-focusing electron storage rings have separated-function lattices, the combined-function lattice would reduce energy loss to synchrotron radiation. Robinson and Hofmann and Zotter have shown how to overcome the anti-damping that was once thought to rule out this possibility. Their formulation is generalized to achieve a more realistic machine design having FODO cells to incorporate the inevitable straight sections between magnets and to allow for any subsequent insertion of nonlinear elements. An analysis is performed to estimate the energy savings for a 50x50 GeV e+e- facility using combined-function magnets
International Nuclear Information System (INIS)
Bagrov, V.G.; Evseevich, A.A.; Obukhov, V.V.; Osetrin, K.E.
1987-01-01
The authors consider the problem of the classification of the Stackel spaces of the electrovacuum with isotropic complete sets. The metrics of the spaces are represented in a form that is convenient for their investigation. We obtain necessary relations for the construction of the field equations
A database for extract solutions in general relativity
International Nuclear Information System (INIS)
Horvath, I.; Horvath, Zs.; Lukacs, B.
1993-07-01
The field of equations of General Relativity are coupled second order partial differential equations. Therefore no general method is known to generate solutions for prescribed initial and boundary conditions. In addition, the meaning of the particular coordinates cannot be known until the metric is not found. Therefore the result must permit arbitrary coordinate transformations, i.e. most kinds of approximating methods are improper. So exact solutions are necessary and each one is an individual product. For storage, retrieval and comparison database handling techniques are needed. A database of 1359 articles is shown (cross-referred at least once) published in 156 more important journals. It can be handled by dBase III plus on IBM PC's. (author) 5 refs.; 5 tabs
General relativity with spin and torsion: Foundations and prospects
International Nuclear Information System (INIS)
Hehl, F.W.; von der Heyde, P.; Kerlick, G.D.; Nester, J.M.
1976-01-01
A generalization of Einstein's gravitational theory is discussed in which the spin of matter as well as its mass plays a dynamical role. The spin of matter couples to a non-Riemannian structure in space-time, Cartan's torsion tensor. The theory which emerges from taking this coupling into account, the U 4 theory of gravitation, predicts, in addition to the usual infinite-range gravitational interaction mediated by the metric field, a new, very weak, spin contact interaction of gravitational origin. We summarize here all the available theoretical evidence that argues for admitting spin and torsion into a relativistic gravitational theory. Not least among this evidence is the demonstration that the U 4 theory arises as a local gauge theory for the Poincare group in space-time. The deviations of the U 4 theory from standard general relativity are estimated, and the prospects for further theoretical development are assessed
The revival of General Relativity at Princeton: Daring Conservatism
Brill, Dieter; Blum, Alexander
2018-01-01
After General Relativity was established in essentially its present form in 1915 it was celebrated as a great success of mathematical physics. But the initial hopes for this theory as a basis for all of physics began to fade in the next several decades, as General Relativity was relegated to the margins of theoretical physics. Its fate began to rise in the 1950's in a revival of interest and research that over time made gravitational physics one of the hottest research topics it is today. One center of this renaissance was Princeton, where two relative newcomers explored new and different approaches to gravitational physics. Robert Dicke showed that gravity is not as inaccessible to experiment as was thought, and John Wheeler propelled it into the mainstream by proposing highly original and imaginative consequences of Einstein's theory. We will concentrate on these ideas that, in his characteristically intriguing style, Wheeler called "Daring Conservatism" - a term well known to his associates, but one he never mentioned in print. With the aid of unpublished manuscripts and notes we will explore Daring Conservatism's origin and motivation, its successes and failures, and the legacy it left behind.
The revival of General Relativity at Princeton: Daring Conservatism
Directory of Open Access Journals (Sweden)
Brill Dieter
2018-01-01
Full Text Available After General Relativity was established in essentially its present form in 1915 it was celebrated as a great success of mathematical physics. But the initial hopes for this theory as a basis for all of physics began to fade in the next several decades, as General Relativity was relegated to the margins of theoretical physics. Its fate began to rise in the 1950's in a revival of interest and research that over time made gravitational physics one of the hottest research topics it is today. One center of this renaissance was Princeton, where two relative newcomers explored new and different approaches to gravitational physics. Robert Dicke showed that gravity is not as inaccessible to experiment as was thought, and John Wheeler propelled it into the mainstream by proposing highly original and imaginative consequences of Einstein's theory. We will concentrate on these ideas that, in his characteristically intriguing style, Wheeler called "Daring Conservatism" -- a term well known to his associates, but one he never mentioned in print. With the aid of unpublished manuscripts and notes we will explore Daring Conservatism's origin and motivation, its successes and failures, and the legacy it left behind.
On complicated continuum models in general relativity theory
International Nuclear Information System (INIS)
Tsypkin, A.G.
1987-01-01
A set of Euler's equations is obtained in the framework of the general relativity theory from the variational equation in the supposition that lagrangian of the material depends on additional (in comparison with classical theories) thermodynamic parameters and taking into account possible irreversible processes. Momentum equations for continuous medium of a thermodynamic closed set are shown to be the consequence of field equations. The problem about the type of energy-momentum material tensor in the presence of derivatives from additional thermodynamic parameters in the number of lagrangian arguments is considered
A superconducting gyroscope to test Einstein's general theory of relativity
Everitt, C. W. F.
1978-01-01
Schiff (1960) proposed a new test of general relativity based on measuring the precessions of the spin axes of gyroscopes in earth orbit. Since 1963 a Stanford research team has been developing an experiment to measure the two effects calculated by Schiff. The gyroscope consists of a uniform sphere of fused quartz 38 mm in diameter, coated with superconductor, electrically suspended and spinning at about 170 Hz in vacuum. The paper describes the proposed flight apparatus and the current state of development of the gyroscope, including techniques for manufacturing and measuring the gyro rotor and housing, generating ultralow magnetic fields, and mechanizing the readout.
Lectures on General Relativity, Cosmology and Quantum Black Holes
Ydri, Badis
2017-07-01
This book is a rigorous text for students in physics and mathematics requiring an introduction to the implications and interpretation of general relativity in areas of cosmology. Readers of this text will be well prepared to follow the theoretical developments in the field and undertake research projects as part of an MSc or PhD programme. This ebook contains interactive Q&A technology, allowing the reader to interact with the text and reveal answers to selected exercises posed by the author within the book. This feature may not function in all formats and on reading devices.
Indefinite-metric quantum field theory of general relativity, 5
International Nuclear Information System (INIS)
Nakanishi, Noboru
1979-01-01
The indefinite-metric quantum field theory of general relativity is extended to the coupled system of the gravitational field and a Dirac field on the basis of the vierbein formalism. The six extra degrees of freedom involved in vierbein are made unobservable by introducing an extra subsidiary condition Q sub(s) + phys> = 0, where Q sub(s) denotes a new BRS charge corresponding to the local Lorentz invariance. It is shown that a manifestly covariant, unitary, canonical theory can be constructed consistently on the basis of the vierbein formalism. (author)
Proposed new test of spin effects in general relativity.
O'Connell, R F
2004-08-20
The recent discovery of a double-pulsar PSR J0737-3039A/B provides an opportunity of unequivocally observing, for the first time, spin effects in general relativity. Existing efforts involve detection of the precession of the spinning body itself. However, for a close binary system, spin effects on the orbit may also be discernible. Not only do they add to the advance of the periastron (by an amount which is small compared to the conventional contribution) but they also give rise to a precession of the orbit about the spin direction. The measurement of such an effect would also give information on the moment of inertia of pulsars.
Conservation and non-conservation in general relativity
International Nuclear Information System (INIS)
Bondi, H.
1990-01-01
The difficulties of conservation laws in general relativity are discussed, with special reference to the non-tangible nature of gravitational energy and its transformation into tangible forms of energy. Inductive transfer of energy is marked out as wholly distinct from wave transfer. Slow (adiabatic) changes are utilized to make clear, in the axi-symmetric case, that the mass of an isolated body is conserved irrespective of any local changes (e.g. of shape) and that in inductive transfer the movement of energy between two bodies can readily be traced by the changes in their masses. (author)
Equivalence of the theories of reciprocity and general relativity
International Nuclear Information System (INIS)
Qadir, A.
1976-01-01
Khan's theory (Nuovo Cimento; 57B:321 (1968) and Int. J. Theor. Phys.; 6:383 (1972)) of reciprocity has been shown to be equivalent to the theory of general relativity (in a conformally flat space-time) in that the same predictions are made physically. It is is proved that, since 'centrifugal forces' are used by Khan, gravitational phenomena are being considered equal in status to electromagnetic phenomena, and hence the difference claimed to exist between Milne's theory and Khan's theory disappears. (author)
Directory of Open Access Journals (Sweden)
Asma Deeb
2018-01-01
Full Text Available Diabetes is a chronic disease and its management is associated with multiple challenges. This is particularly the case in children and adolescents. Factors that contribute to difficulties in managing diabetes in youth include psychological characteristics, family dynamics, and social behavior. The purpose of this article is to highlight some psychological issues in children and adolescents with diabetes. We aim to present selected case scenarios encountered by health professionals and to provide tips on strategies for managing psychological aspect of diabetes. We tackle the psychological issues related to diabetes under four main categories: maladaptive disorders, eating disorders, family psychopathology, and family dysfunction. Psychotherapy and psychoanalysis are useful modalities in diabetes management. The psychological intervention is aimed at supporting patients and families to reach a balance between a normal family routine and a good glycemic control. We demonstrate unique requirements in coordinating care for children and adolescents with diabetes and highlight the importance of encouraging a positive behavior. Managing diabetes in children and adolescents needs to be in the form of a collaborative work between health care professionals, children and adolescents, and their families. Caring, supportive family backed up by experienced multidisciplinary team is the best approach to prevent psychological difficulties.
Deeb, Asma; Akle, Mariette; Al Ozairi, Abdulla; Cameron, Fergus
2018-01-01
Diabetes is a chronic disease and its management is associated with multiple challenges. This is particularly the case in children and adolescents. Factors that contribute to difficulties in managing diabetes in youth include psychological characteristics, family dynamics, and social behavior. The purpose of this article is to highlight some psychological issues in children and adolescents with diabetes. We aim to present selected case scenarios encountered by health professionals and to provide tips on strategies for managing psychological aspect of diabetes. We tackle the psychological issues related to diabetes under four main categories: maladaptive disorders, eating disorders, family psychopathology, and family dysfunction. Psychotherapy and psychoanalysis are useful modalities in diabetes management. The psychological intervention is aimed at supporting patients and families to reach a balance between a normal family routine and a good glycemic control. We demonstrate unique requirements in coordinating care for children and adolescents with diabetes and highlight the importance of encouraging a positive behavior. Managing diabetes in children and adolescents needs to be in the form of a collaborative work between health care professionals, children and adolescents, and their families. Caring, supportive family backed up by experienced multidisciplinary team is the best approach to prevent psychological difficulties.
Gyroscope precession in special and general relativity from basic principles
Jonsson, Rickard M.
2007-05-01
In special relativity a gyroscope that is suspended in a torque-free manner will precess as it is moved along a curved path relative to an inertial frame S. We explain this effect, which is known as Thomas precession, by considering a real grid that moves along with the gyroscope, and that by definition is not rotating as observed from its own momentary inertial rest frame. From the basic properties of the Lorentz transformation we deduce how the form and rotation of the grid (and hence the gyroscope) will evolve relative to S. As an intermediate step we consider how the grid would appear if it were not length contracted along the direction of motion. We show that the uncontracted grid obeys a simple law of rotation. This law simplifies the analysis of spin precession compared to more traditional approaches based on Fermi transport. We also consider gyroscope precession relative to an accelerated reference frame and show that there are extra precession effects that can be explained in a way analogous to the Thomas precession. Although fully relativistically correct, the entire analysis is carried out using three-vectors. By using the equivalence principle the formalism can also be applied to static spacetimes in general relativity. As an example, we calculate the precession of a gyroscope orbiting a static black hole.
Kerr-Taub-NUT General Frame, Energy, and Momentum in Teleparallel Equivalent of General Relativity
Directory of Open Access Journals (Sweden)
Gamal G. L. Nashed
2012-01-01
Full Text Available A new exact solution describing a general stationary and axisymmetric object of the gravitational field in the framework of teleparallel equivalent of general relativity (TEGR is derived. The solution is characterized by three parameters “the gravitational mass M, the rotation a, and the NUT L.” The vierbein field is axially symmetric, and the associated metric gives the Kerr-Taub-NUT spacetime. Calculation of the total energy using two different methods, the gravitational energy momentum and the Riemannian connection 1-form Γα̃β, is carried out. It is shown that the two methods give the same results of energy and momentum. The value of energy is shown to depend on the mass M and the NUT parameter L. If L is vanishing, then the total energy reduced to the energy of Kerr black hole.
Distinguishing f(R) theories from general relativity by gravitational lensing effect
Energy Technology Data Exchange (ETDEWEB)
Liu, Hongguang [Beijing Normal University, Department of Physics, Beijing (China); Aix Marseille Universite et Universite de Toulon, Centre de Physique Theorique (UMR 7332), Marseille (France); Wang, Xin; Li, Haida; Ma, Yongge [Beijing Normal University, Department of Physics, Beijing (China)
2017-11-15
The post-Newtonian formulation of a general class of f(R) theories is set up in a third-order approximation. It turns out that the information of a specific form of f(R) gravity is encoded in the Yukawa potential, which is contained in the perturbative expansion of the metric components. Although the Yukawa potential is canceled in the second-order expression of the effective refraction index of light, detailed analysis shows that the difference of the lensing effect between the f(R) gravity and general relativity does appear at the third order when √(f''(0)/f{sup '}(0)) is larger than the distance d{sub 0} to the gravitational source. However, the difference between these two kinds of theories will disappear in the axially symmetric spacetime region. Therefore only in very rare case the f(R) theories are distinguishable from general relativity by gravitational lensing effect in a third-order post-Newtonian approximation. (orig.)
Theory of Nonlocal Point Transformations in General Relativity
Directory of Open Access Journals (Sweden)
Massimo Tessarotto
2016-01-01
Full Text Available A discussion of the functional setting customarily adopted in General Relativity (GR is proposed. This is based on the introduction of the notion of nonlocal point transformations (NLPTs. While allowing the extension of the traditional concept of GR-reference frame, NLPTs are important because they permit the explicit determination of the map between intrinsically different and generally curved space-times expressed in arbitrary coordinate systems. For this purpose in the paper the mathematical foundations of NLPT-theory are laid down and basic physical implications are considered. In particular, explicit applications of the theory are proposed, which concern (1 a solution to the so-called Einstein teleparallel problem in the framework of NLPT-theory; (2 the determination of the tensor transformation laws holding for the acceleration 4-tensor with respect to the group of NLPTs and the identification of NLPT-acceleration effects, namely, the relationship established via general NLPT between particle 4-acceleration tensors existing in different curved space-times; (3 the construction of the nonlocal transformation law connecting different diagonal metric tensors solution to the Einstein field equations; and (4 the diagonalization of nondiagonal metric tensors.
Geometrical determination of the constant of motion in General Relativity
International Nuclear Information System (INIS)
Catoni, F.; Cannata, R.; Zampetti, P.
2009-01-01
In recent time a theorem, due to E. Beltrami, through which the integration of the geodesic equations of a curved manifold is obtained by means of a merely geometric method, has been revisited. This way of dealing with the problem is well in accordance with the geometric spirit of the Theory of General Relativity. In this paper we show another relevant consequence of this method. Actually, the constants of the motion, introduced in this geometrical way that is completely independent of Newton theory, are related to the conservation laws for test particles in the Einstein theory. These conservation laws may be compared with the conservation laws of Newton. In particular, by the conservation of energy (E) and the L z component of angular momentum, the equivalence of the conservation laws for the Schwarzschild field is verified and the difference between Newton and Einstein theories for the rotating bodies (Kerr metric) is obtained in a straightforward way.
The problem of time quantum mechanics versus general relativity
Anderson, Edward
2017-01-01
This book is a treatise on time and on background independence in physics. It first considers how time is conceived of in each accepted paradigm of physics: Newtonian, special relativity, quantum mechanics (QM) and general relativity (GR). Substantial differences are moreover uncovered between what is meant by time in QM and in GR. These differences jointly source the Problem of Time: Nine interlinked facets which arise upon attempting concurrent treatment of the QM and GR paradigms, as is required in particular for a background independent theory of quantum gravity. A sizeable proportion of current quantum gravity programs - e.g. geometrodynamical and loop quantum gravity approaches to quantum GR, quantum cosmology, supergravity and M-theory - are background independent in this sense. This book's foundational topic is thus furthermore of practical relevance in the ongoing development of quantum gravity programs. This book shows moreover that eight of the nine facets of the Problem of Time already occur upon ...
Nonlinear generalization of special relativity at very high energies
International Nuclear Information System (INIS)
Winterberg, F.
1984-01-01
It is shown, that the introduction of a fundamental length constant into the operator representation of the quantum mechanical commutation relations, as suggested by Bagge, leads to a nonlinear generalization of the Lorentz transformations. The theory requires the introduction of a substratum (ether) and which can be identified as the zero point vacuum energy. At very high energies a non-Lorentz invariant behaviour for the cross sections between elementary particles is predicted. Using the Einstein clock synchronisation definition, the velocity of light is also constant and equal to c in the new theory, but the zero point vacuum energy becomes finite, as are all other quantities which are divergent in Lorentz invariant quantum field theories. In the limiting case where the length constant is set equal to zero, the zero point vacuum energy diverges and special relativity is recovered. (orig.) [de
Correlated quadratures of resonance fluorescence and the generalized uncertainty relation
Arnoldus, Henk F.; George, Thomas F.; Gross, Rolf W. F.
1994-01-01
Resonance fluorescence from a two-state atom has been predicted to exhibit quadrature squeezing below the Heisenberg uncertainty limit, provided that the optical parameters (Rabi frequency, detuning, laser linewidth, etc.) are chosen carefully. When the correlation between two quadratures of the radiation field does not vanish, however, the Heisenberg limit for quantum fluctuations might be an unrealistic lower bound. A generalized uncertainty relation, due to Schroedinger, takes into account the possible correlation between the quadrature components of the radiation, and it suggests a modified definition of squeezing. We show that the coherence between the two levels of a laser-driven atom is responsible for the correlation between the quadrature components of the emitted fluorescence, and that the Schrodinger uncertainty limit increases monotonically with the coherence. On the other hand, the fluctuations in the quadrature field diminish with an increasing coherence, and can disappear completely when the coherence reaches 1/2, provided that certain phase relations hold.
Einstein and Beyond: A Critical Perspective on General Relativity
Directory of Open Access Journals (Sweden)
Ram Gopal Vishwakarma
2016-05-01
Full Text Available An alternative approach to Einstein’s theory of General Relativity (GR is reviewed, which is motivated by a range of serious theoretical issues inflicting the theory, such as the cosmological constant problem, presence of non-Machian solutions, problems related with the energy-stress tensor T i k and unphysical solutions. The new approach emanates from a critical analysis of these problems, providing a novel insight that the matter fields, together with the ensuing gravitational field, are already present inherently in the spacetime without taking recourse to T i k . Supported by lots of evidence, the new insight revolutionizes our views on the representation of the source of gravitation and establishes the spacetime itself as the source, which becomes crucial for understanding the unresolved issues in a unified manner. This leads to a new paradigm in GR by establishing equation R i k = 0 as the field equation of gravitation plus inertia in the very presence of matter.
Zalaletdinov, R. M.
1998-04-01
The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the geometry of macroscopic space-time, which follows from averaging Cartan's structure equations, is described and the correlation tensors present in the theory are discussed. The macroscopic field equations (averaged Einstein's equations) derived in the framework of the approach are presented and their structure is analysed. The correspondence principle for macroscopic gravity is formulated and a definition of the stress-energy tensor for the macroscopic gravitational field is proposed. It is shown that the physical meaning of using Einstein's equations with a hydrodynamic stress-energy tensor in looking for cosmological models means neglecting all gravitational field correlations. The system of macroscopic gravity equations to be solved when the correlations are taken into consideration is given and described.
Fixing extensions to general relativity in the nonlinear regime
Cayuso, Juan; Ortiz, Néstor; Lehner, Luis
2017-10-01
The question of what gravitational theory could supersede General Relativity has been central in theoretical physics for decades. Many disparate alternatives have been proposed motivated by cosmology, quantum gravity and phenomenological angles, and have been subjected to tests derived from cosmological, solar system and pulsar observations typically restricted to linearized regimes. Gravitational waves from compact binaries provide new opportunities to probe these theories in the strongly gravitating/highly dynamical regimes. To this end however, a reliable understanding of the dynamics in such a regime is required. Unfortunately, most of these theories fail to define well posed initial value problems, which prevents at face value from meeting such challenge. In this work, we introduce a consistent program able to remedy this situation. This program is inspired in the approach to "fixing" viscous relativistic hydrodynamics introduced by Israel and Stewart in the late 70's. We illustrate how to implement this approach to control undesirable effects of higher order derivatives in gravity theories and argue how the modified system still captures the true dynamics of the putative underlying theories in 3 +1 dimensions. We sketch the implementation of this idea in a couple of effective theories of gravity, one in the context of Noncommutative Geometry, and one in the context of Chern-Simons modified General Relativity.
The generalized scheme-independent Crewther relation in QCD
Shen, Jian-Ming; Wu, Xing-Gang; Ma, Yang; Brodsky, Stanley J.
2017-07-01
The Principle of Maximal Conformality (PMC) provides a systematic way to set the renormalization scales order-by-order for any perturbative QCD calculable processes. The resulting predictions are independent of the choice of renormalization scheme, a requirement of renormalization group invariance. The Crewther relation, which was originally derived as a consequence of conformally invariant field theory, provides a remarkable connection between two observables when the β function vanishes: one can show that the product of the Bjorken sum rule for spin-dependent deep inelastic lepton-nucleon scattering times the Adler function, defined from the cross section for electron-positron annihilation into hadrons, has no pQCD radiative corrections. The ;Generalized Crewther Relation; relates these two observables for physical QCD with nonzero β function; specifically, it connects the non-singlet Adler function (Dns) to the Bjorken sum rule coefficient for polarized deep-inelastic electron scattering (CBjp) at leading twist. A scheme-dependent ΔCSB-term appears in the analysis in order to compensate for the conformal symmetry breaking (CSB) terms from perturbative QCD. In conventional analyses, this normally leads to unphysical dependence in both the choice of the renormalization scheme and the choice of the initial scale at any finite order. However, by applying PMC scale-setting, we can fix the scales of the QCD coupling unambiguously at every order of pQCD. The result is that both Dns and the inverse coefficient CBjp-1 have identical pQCD coefficients, which also exactly match the coefficients of the corresponding conformal theory. Thus one obtains a new generalized Crewther relation for QCD which connects two effective charges, αˆd (Q) =∑i≥1 αˆg1 i (Qi), at their respective physical scales. This identity is independent of the choice of the renormalization scheme at any finite order, and the dependence on the choice of the initial scale is negligible. Similar
Accelerating particles in general relativity (stationary C-metric)
International Nuclear Information System (INIS)
Farhoosh, H.
1979-01-01
The purpose of this thesis is to study the physical and geometrical properties of uniformly accelerating particles in the general theory of relativity and it consists of four main parts. In the first part the structure of the Killing horizons in the static vacuum C-metric which represents the gravitational field of a uniformly accelerating Schwarzschild like particle (non-rotating and spherically symmetric) is studied. In the second part these results are generalized to include the effects of the rotation of the source. For small acceleration and small rotation this solution reveals the existance of three Killing horizons. Two the these horizons are the Schwarzschild and the Rindler surfaces which are mainly due to the mass and the acceleration of the particle, respectively. In part three the radial geodesic and non-geodesic motions in the static vacuum C-metric (non-rotating case) are investigated. The effect of the dragging of the inertial frame is also shown in this part. In part four the radiative behavior of the stationary charged C-metric representing the electro-gravitational field of a uniformly accelerating and rotating charged particle with magnetic monopole and the NUT-parameter are investigated. The physical quantities - the news function, mass loss, mass, charge and the multipole moments - are calculated. It is also shown in this part that the magnetic monopole in the presence of rotation and acceleration affects the electric charge
Ambiguous tests of general relativity on cosmological scales
International Nuclear Information System (INIS)
Zuntz, Joe; Baker, Tessa; Ferreira, Pedro G.; Skordis, Constantinos
2012-01-01
There are a number of approaches to testing General Relativity (GR) on linear scales using parameterized frameworks for modifying cosmological perturbation theory. It is sometimes assumed that the details of any given parameterization are unimportant if one uses it as a diagnostic for deviations from GR. In this brief report we argue that this is not necessarily so. First we show that adopting alternative combinations of modifications to the field equations significantly changes the constraints that one obtains. In addition, we show that using a parameterization with insufficient freedom significantly tightens the apparent theoretical constraints. Fundamentally we argue that it is almost never appropriate to consider modifications to the perturbed Einstein equations as being constraints on the effective gravitational constant, for example, in the same sense that solar system constraints are. The only consistent modifications are either those that grant near-total freedom, as in decomposition methods, or ones which map directly to a particular part of theory space
Determinants related to gender differences in general practice utilization
DEFF Research Database (Denmark)
Jørgensen, Jeanette Therming; Andersen, John Sahl; Tjønneland, Anne
2016-01-01
OBJECTIVE: This study aims to describe the determinants related to gender differences in the GP utilization in Danish population aged 50-65 years. DESIGN: Cohort-based cross-sectional study. SETTING: Danish general practice. SUBJECTS: Totally, 54,849 participants of the Danish Diet, Cancer...... information on lifestyle (smoking, body mass index (BMI), alcohol use, physical activity), medical conditions (somatic and mental), employment, education, gravidity, and hormone therapy (HT) use was collected by questionnaire. RESULTS: Women had on average 4.1 and men 2.8 consultations per year. In a crude....... Strongest determinants for GP use among Danish adults aged 50-65 years were the presence of medical conditions (somatic and mental) and unemployment, while lifestyle factors (e.g., body mass index, alcohol consumption and smoking) had minor effect....
Motivations for anti-gravity in general relativity
International Nuclear Information System (INIS)
Chardin, G.
1996-05-01
Arguments are presented showing that it is natural to interpret the negative mass part of the Kerr solution as representing the geometry experienced by antimatter. The C, P and T discrete transformations are considered for this geometry. The C and T properties of the proposed identification are found to be in agreement with the usual representation of antimatter. In addition, a property of perfect stigmatism through Kerr wormholes which allows general relativity to mimic anti-gravity is conjectured. Kerr wormholes would then act as 'super-mirrors' reversing the C, P and T images of an object seen through it. This interpretation is subjected to several experimental tests and able to provide an explanation, without any free parameter, of the 'CP'-violation observed in the neutral kaon system. (K.A.)
Rotating collapse of stellar iron cores in general relativity
International Nuclear Information System (INIS)
Ott, C D; Dimmelmeier, H; Marek, A; Janka, H-T; Zink, B; Hawke, I; Schnetter, E
2007-01-01
We present results from the first 2 + 1 and 3 + 1 simulations of the collapse of rotating stellar iron cores in general relativity employing a finite-temperature equation of state and an approximate treatment of deleptonization during collapse. We compare full 3 + 1 and conformally-flat spacetime evolution methods and find that the conformally-flat treatment is sufficiently accurate for the core-collapse supernova problem. We focus on the gravitational wave (GW) emission from rotating collapse, core bounce and early postbounce phases. Our results indicate that the GW signature of these phases is much more generic than previously estimated. In addition, we track the growth of a nonaxisymmetric instability of dominant m = 1 character in two of our models that leads to prolonged narrow-band GW emission at ∼920-930 Hz over several tens of milliseconds
Bell's inequalities from the field concept in general relativity
International Nuclear Information System (INIS)
Sachs, M.
1980-01-01
A nonlinear field theory of matter, based axiomatically on general relativity, has an asymptotic, low-energy limit that predicts the outcome of experimental tests of Bell's inequalities. The inequalities should follow if spin-correlated, spin-1/2 particles, observed in coincidence, were a spacelike distance apart; they should be violated if they were separated by timelike distances. The experiment at timelike separations, for scattered protons observed in coincidence, was carried out by Lahemi-Rachti and Mittig and, thus far, agrees with this theory. Extension of the low-energy pp scattering experiment to observations at spacelike distances is suggested, with the prediction that agreement should be obtained with Bell's inequalities there. (author)
Commutative deformations of general relativity: nonlocality, causality, and dark matter
Energy Technology Data Exchange (ETDEWEB)
De Vegvar, P.G.N. [SWK Research, Bellingham, WA (United States)
2017-01-15
Hopf algebra methods are applied to study Drinfeld twists of (3+1)-diffeomorphisms and deformed general relativity on commutative manifolds. A classical nonlocality length scale is produced above which microcausality emerges. Matter fields are utilized to generate self-consistent Abelian Drinfeld twists in a background independent manner and their continuous and discrete symmetries are examined. There is negligible experimental effect on the standard model of particles. While baryonic twist producing matter would begin to behave acausally for rest masses above ∝1-10 TeV, other possibilities are viable dark matter candidates or a right-handed neutrino. First order deformed Maxwell equations are derived and yield immeasurably small cosmological dispersion and produce a propagation horizon only for photons at or above Planck energies. This model incorporates dark matter without any appeal to extra dimensions, supersymmetry, strings, grand unified theories, mirror worlds, or modifications of Newtonian dynamics. (orig.)
A non-local variable for general relativity
International Nuclear Information System (INIS)
Kozameh, C.N.; Newman, E.T.
1983-01-01
The usual description of differential geometry and general relativity is in terms of local fields, e.g. the metric, the curvature tensor, etc, which satisfy local differential equations. The authors introduce a new non-local field (Z) from which the local fields can be derived. Basically Z, though it is non-local, should be thought of as a function on the bundle of null directions on a space-time. The program can be divided into two parts; first the authors want to show the geometric meaning of and the relationship between Z and the local field. Then they want to provide field equations (non-local) for Z which will be equivalent to the vacuum Einstein equations for the local field. (Auth.)
Motivations for anti-gravity in general relativity
Energy Technology Data Exchange (ETDEWEB)
Chardin, G. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee
1996-05-01
Arguments are presented showing that it is natural to interpret the negative mass part of the Kerr solution as representing the geometry experienced by antimatter. The C, P and T discrete transformations are considered for this geometry. The C and T properties of the proposed identification are found to be in agreement with the usual representation of antimatter. In addition, a property of perfect stigmatism through Kerr wormholes which allows general relativity to mimic anti-gravity is conjectured. Kerr wormholes would then act as `super-mirrors` reversing the C, P and T images of an object seen through it. This interpretation is subjected to several experimental tests and able to provide an explanation, without any free parameter, of the `CP`-violation observed in the neutral kaon system. (K.A.). 37 refs.
CPT symmetry and antimatter gravity in general relativity
Villata, M.
2011-04-01
The gravitational behavior of antimatter is still unknown. While we may be confident that antimatter is self-attractive, the interaction between matter and antimatter might be either attractive or repulsive. We investigate this issue on theoretical grounds. Starting from the CPT invariance of physical laws, we transform matter into antimatter in the equations of both electrodynamics and gravitation. In the former case, the result is the well-known change of sign of the electric charge. In the latter, we find that the gravitational interaction between matter and antimatter is a mutual repulsion, i.e. antigravity appears as a prediction of general relativity when CPT is applied. This result supports cosmological models attempting to explain the Universe accelerated expansion in terms of a matter-antimatter repulsive interaction.
On special and general relativity theory. 24. ed.
International Nuclear Information System (INIS)
Einstein, Albert
2009-01-01
The present booklet shall mediate to such an as possible exact view in relativity theory, who are especially interested for the theory from a generally scientific, philosophical, point of view, without mastering the mathematical apparatus. The lecture presupposes some maturity knowledge and - in spite of the shortness of the booklet - quite much perseverance and strength of mind. The author has token very much efforts in order to present the main thoughts as distinctly and simply as possible, in the whole in such a sequence and in such connection, as it has really been arose. With the aim of distinctiveness it seemed to me unavoidable to repeat myself frequently without paying the smallest regard to the elegance of the presentation; I maintained conscientiously the prescription of the ingenious theoretician L. Boltzmann, elegance should by the object of the taylors ans shoemakers [de
General Relativity and Cosmology: Unsolved Questions and Future Directions
Directory of Open Access Journals (Sweden)
Ivan Debono
2016-09-01
Full Text Available For the last 100 years, General Relativity (GR has taken over the gravitational theory mantle held by Newtonian Gravity for the previous 200 years. This article reviews the status of GR in terms of its self-consistency, completeness, and the evidence provided by observations, which have allowed GR to remain the champion of gravitational theories against several other classes of competing theories. We pay particular attention to the role of GR and gravity in cosmology, one of the areas in which one gravity dominates and new phenomena and effects challenge the orthodoxy. We also review other areas where there are likely conflicts pointing to the need to replace or revise GR to represent correctly observations and consistent theoretical framework. Observations have long been key both to the theoretical liveliness and viability of GR. We conclude with a discussion of the likely developments over the next 100 years.
Probing strong-field general relativity near black holes
CERN. Geneva; Alvarez-Gaumé, Luís
2005-01-01
Nature has sprinkled black holes of various sizes throughout the universe, from stellar mass black holes in X-ray sources to supermassive black holes of billions of solar masses in quasars. Astronomers today are probing the spacetime near black holes using X-rays, and gravitational waves will open a different view in the near future. These tools give us an unprecedented opportunity to test ultra-strong-field general relativity, including the fundamental theorem of the uniqueness of the Kerr metric and Roger Penrose's cosmic censorship conjecture. Already, fascinating studies of spectral lines are showing the extreme gravitational lensing effects near black holes and allowing crude measurements of black hole spin. When the ESA-NASA gravitational wave detector LISA begins its observations in about 10 years, it will make measurements of dynamical spacetimes near black holes with an accuracy greater even than that which theoreticians can reach with their computations today. Most importantly, when gravitational wa...
The canonical Lagrangian approach to three-space general relativity
Shyam, Vasudev; Venkatesh, Madhavan
2013-07-01
We study the action for the three-space formalism of general relativity, better known as the Barbour-Foster-Ó Murchadha action, which is a square-root Baierlein-Sharp-Wheeler action. In particular, we explore the (pre)symplectic structure by pulling it back via a Legendre map to the tangent bundle of the configuration space of this action. With it we attain the canonical Lagrangian vector field which generates the gauge transformations (3-diffeomorphisms) and the true physical evolution of the system. This vector field encapsulates all the dynamics of the system. We also discuss briefly the observables and perennials for this theory. We then present a symplectic reduction of the constrained phase space.
Dynamics of plane-symmetric thin walls in general relativity
International Nuclear Information System (INIS)
Wang, A.
1992-01-01
Plane walls (including plane domain walls) without reflection symmetry are studied in the framework of Einstein's general relativity. Using the distribution theory, all the Einstein field equations and Bianchi identities are split into two groups: one holding in the regions outside of the wall and the other holding at the wall. The Einstein field equations at the wall are found to take a very simple form, and given explicitly in terms of the discontinuities of the metric coefficients and their derivatives. The Bianchi identities at the wall are also given explicitly. Using the latter, the interaction of a plane wall with gravitational waves and some specific matter fields is studied. In particular, it is found that, when a gravitational plane wave passes through a wall, if the wall has no reflection symmetry, the phenomena, such as reflection, stimulation, or absorption, in general, occur. It is also found that, unlike for gravitational waves, a massless scalar wave or an electromagnetic wave continuously passes through a wall without any reflection. The repulsion and attraction of a plane wall are also studied. It is found that the acceleration of an observer who is at rest relative to the wall usually consists of three parts: one is due to the force produced by the wall, the second is due to the force produced by the space-time curvature, which is zero if the wall has reflection symmetry, and the last is due to the accelerated motion of the wall. As a result, a repulsive (attractive) plane wall may not be repulsive (attractive) at all. Finally, the collision and interaction among the walls are studied
The global existence problem and cosmic censorship in general relativity
International Nuclear Information System (INIS)
Moncrief, V.; Eardley, D.M.
1981-01-01
Two global existence conjectures for the Einstein equations are formulated and their relevance to the cosmic censorship conjecture discussed. It is argued that the reformulation of the cosmic censorship conjecture as a global existence problem renders it more amenable to direct analytical attack. To demonstrate the facility of this approach the cosmological version of the global existence conjecture is proved for the Gowdy spacetimes on T 3 X R. (author)
General relativity and gauge gravity theories of higher order
International Nuclear Information System (INIS)
Konopleva, N.P.
1998-01-01
It is a short review of today's gauge gravity theories and their relations with Einstein General Relativity. The conceptions of construction of the gauge gravity theories with higher derivatives are analyzed. GR is regarded as the gauge gravity theory corresponding to the choice of G ∞4 as the local gauge symmetry group and the symmetrical tensor of rank two g μν as the field variable. Using the mathematical technique, single for all fundamental interactions (namely variational formalism for infinite Lie groups), we can obtain Einstein's theory as the gauge theory without any changes. All other gauge approaches lead to non-Einstein theories of gravity. But above-mentioned mathematical technique permits us to construct the gauge gravity theory of higher order (for instance SO (3,1)-gravity) so that all vacuum solutions of Einstein equations are the solutions of the SO (3,1)-gravity theory. The structure of equations of SO(3,1)-gravity becomes analogous to Weeler-Misner geometrodynamics one
Energy Technology Data Exchange (ETDEWEB)
Dubois, I.
1999-12-06
Starch is a polymeric carbohydrate derivative with anhydro-glucose units and is extracted from the tissues of certain plants. In its native form, starch granule is non soluble in cold water and therefore most applications need a cooking period in the presence of an excess of water. The cooking treatment is therefore associated with large changes in viscosity. Overall, starch suspensions properties are strongly influenced by starch botanical origins, shearing and heating conditions under which they are prepared. Their properties can be modulated though chemical modifications depending on their uses in the petroleum industry. This study focuses on the relations between structure and physico-chemical, rheological and filtration properties of modified starches. These starches are originated from native potato, i. e. hydroxy-propyl and/or crosslinked starches above or below the gelatinization temperature. The samples were characterised in terms of swelling capacity, average granule size distribution and molecular weight. Microscopic methods were used to investigate starch structure. Relations were established between the rheological properties and the physico-chemical parameters. These properties are governed by the deformability and rigidity parameters as a function of the concentration. The best samples were then chosen and were submitted to the high temperature (140 deg. C - 160 deg. C), high shearing (16000 tr/ mn) and salinity (CaCl{sub 2}, 1M). The physico-chemical and rheological studies showed that the starch system which is crosslinked below the gelatinization temperature is more resistant that the samples crosslinked above the gelatinization temperature. Then, a drilling fluid formulation was investigated. The filtration results evidenced an increase of the cake permeability in the presence of starch particles but the good stability of these samples permits their uses for high temperature. Thus, non crosslinked / crosslinked starch mixtures were investigated
Energy Technology Data Exchange (ETDEWEB)
Dubois, I
1999-12-06
Starch is a polymeric carbohydrate derivative with anhydro-glucose units and is extracted from the tissues of certain plants. In its native form, starch granule is non soluble in cold water and therefore most applications need a cooking period in the presence of an excess of water. The cooking treatment is therefore associated with large changes in viscosity. Overall, starch suspensions properties are strongly influenced by starch botanical origins, shearing and heating conditions under which they are prepared. Their properties can be modulated though chemical modifications depending on their uses in the petroleum industry. This study focuses on the relations between structure and physico-chemical, rheological and filtration properties of modified starches. These starches are originated from native potato, i. e. hydroxy-propyl and/or crosslinked starches above or below the gelatinization temperature. The samples were characterised in terms of swelling capacity, average granule size distribution and molecular weight. Microscopic methods were used to investigate starch structure. Relations were established between the rheological properties and the physico-chemical parameters. These properties are governed by the deformability and rigidity parameters as a function of the concentration. The best samples were then chosen and were submitted to the high temperature (140 deg. C - 160 deg. C), high shearing (16000 tr/ mn) and salinity (CaCl{sub 2}, 1M). The physico-chemical and rheological studies showed that the starch system which is crosslinked below the gelatinization temperature is more resistant that the samples crosslinked above the gelatinization temperature. Then, a drilling fluid formulation was investigated. The filtration results evidenced an increase of the cake permeability in the presence of starch particles but the good stability of these samples permits their uses for high temperature. Thus, non crosslinked / crosslinked starch mixtures were investigated
Inferring general relations between network characteristics from specific network ensembles.
Cardanobile, Stefano; Pernice, Volker; Deger, Moritz; Rotter, Stefan
2012-01-01
Different network models have been suggested for the topology underlying complex interactions in natural systems. These models are aimed at replicating specific statistical features encountered in real-world networks. However, it is rarely considered to which degree the results obtained for one particular network class can be extrapolated to real-world networks. We address this issue by comparing different classical and more recently developed network models with respect to their ability to generate networks with large structural variability. In particular, we consider the statistical constraints which the respective construction scheme imposes on the generated networks. After having identified the most variable networks, we address the issue of which constraints are common to all network classes and are thus suitable candidates for being generic statistical laws of complex networks. In fact, we find that generic, not model-related dependencies between different network characteristics do exist. This makes it possible to infer global features from local ones using regression models trained on networks with high generalization power. Our results confirm and extend previous findings regarding the synchronization properties of neural networks. Our method seems especially relevant for large networks, which are difficult to map completely, like the neural networks in the brain. The structure of such large networks cannot be fully sampled with the present technology. Our approach provides a method to estimate global properties of under-sampled networks in good approximation. Finally, we demonstrate on three different data sets (C. elegans neuronal network, R. prowazekii metabolic network, and a network of synonyms extracted from Roget's Thesaurus) that real-world networks have statistical relations compatible with those obtained using regression models.
Spinning solutions in general relativity with infinite central density
Flammer, P. D.
2018-05-01
This paper presents general relativistic numerical simulations of uniformly rotating polytropes. Equations are developed using MSQI coordinates, but taking a logarithm of the radial coordinate. The result is relatively simple elliptical differential equations. Due to the logarithmic scale, we can resolve solutions with near-singular mass distributions near their center, while the solution domain extends many orders of magnitude larger than the radius of the distribution (to connect with flat space-time). Rotating solutions are found with very high central energy densities for a range of adiabatic exponents. Analytically, assuming the pressure is proportional to the energy density (which is true for polytropes in the limit of large energy density), we determine the small radius behavior of the metric potentials and energy density. This small radius behavior agrees well with the small radius behavior of large central density numerical results, lending confidence to our numerical approach. We compare results with rotating solutions available in the literature, which show good agreement. We study the stability of spherical solutions: instability sets in at the first maximum in mass versus central energy density; this is also consistent with results in the literature, and further lends confidence to the numerical approach.
Simulation of merging neutron stars in full general relativity
International Nuclear Information System (INIS)
Shibata, M.
2001-01-01
We have performed 3D numerical simulations for merger of equal mass binary neutron stars in full general relativity. We adopt a Γ-law equation of state in the form P = (Γ - 1)ρε where P, ρ, ε and Γ are the pressure, rest mass density, specific internal energy, and the adiabatic constant. As initial conditions, we adopt models of irrotational binary neutron stars in a quasiequilibrium state. Simulations have been carried out for a wide range of Γ and compactness of neutron stars, paying particular attention to the final product and gravitational waves. We find that the final product depends sensitively on the initial compactness of the neutron stars: In a merger between sufficiently compact neutron stars, a black hole is formed in a dynamical timescale. As the compactness is decreased, the formation timescale becomes longer and longer. It is also found that a differentially rotating massive neutron star is formed instead of a black hole for less compact binary cases. In the case of black hole formation, the disk mass around the black hole appears to be very small; less than 1% of the total rest mass. It is indicated that waveforms of high-frequency gravitational waves after merger depend strongly on the compactness of neutron stars before the merger. We point out importance of detecting such gravitational waves of high frequency to constrain the maximum allowed mass of neutron stars. (author)
Gravitational field of massive point particle in general relativity
International Nuclear Information System (INIS)
Fiziev, P.P.
2003-10-01
Using various gauges of the radial coordinate we give a description of the static spherically symmetric space-times with point singularity at the center and vacuum outside the singularity. We show that in general relativity (GR) there exist infinitely many such solutions to the Einstein equations which are physically different and only some of them describe the gravitational field of a single massive point particle. In particular, we show that the widespread Hilbert's form of Schwarzschild solution does not solve the Einstein equations with a massive point particle's stress-energy tensor. Novel normal coordinates for the field and a new physical class of gauges are proposed, in this way achieving a correct description of a point mass source in GR. We also introduce a gravitational mass defect of a point particle and determine the dependence of the solutions on this mass defect. In addition we give invariant characteristics of the physically and geometrically different classes of spherically symmetric static space-times created by one point mass. (author)
A New Solution for Einstein Field Equation in General Relativity
Mousavi, Sadegh
2006-05-01
There are different solutions for Einstein field equation in general relativity that they have been proposed by different people the most important solutions are Schwarzchild, Reissner Nordstrom, Kerr and Kerr Newmam. However, each one of these solutions limited to special case. I've found a new solution for Einstein field equation which is more complete than all previous ones and this solution contains the previous solutions as its special forms. In this talk I will present my new metric for Einstein field equation and the Christofel symbols and Richi and Rieman tensor components for the new metric that I have calculated them by GR TENSOR software. As a result I will determine the actual movement of black holes which is different From Kerr black hole's movement. Finally this new solution predicts, existence of a new and constant field in the nature (that nobody can found it up to now), so in this talk I will introduce this new field and even I will calculate the amount of this field. SADEGH MOUSAVI, Amirkabir University of Technology.
A Time Domain Waveform for Testing General Relativity
International Nuclear Information System (INIS)
Huwyler, Cédric; Jetzer, Philippe; Porter, Edward K
2015-01-01
Gravitational-wave parameter estimation is only as good as the theory the waveform generation models are based upon. It is therefore crucial to test General Relativity (GR) once data becomes available. Many previous works, such as studies connected with the ppE framework by Yunes and Pretorius, rely on the stationary phase approximation (SPA) to model deviations from GR in the frequency domain. As Fast Fourier Transform algorithms have become considerably faster and in order to circumvent possible problems with the SPA, we test GR with corrected time domain waveforms instead of SPA waveforms. Since a considerable amount of work has been done already in the field using SPA waveforms, we establish a connection between leading-order-corrected waveforms in time and frequency domain, concentrating on phase-only corrected terms. In a Markov Chain Monte Carlo study, whose results are preliminary and will only be available later, we will assess the ability of the eLISA detector to measure deviations from GR for signals coming from supermassive black hole inspirals using these corrected waveforms. (paper)
General relativity cosmological models without the big bang
International Nuclear Information System (INIS)
Rosen, N.
1985-01-01
Attention is given to the so-called standard model of the universe in the framework of the general theory of relativity. This model is taken to be homogeneous and isotropic and filled with an ideal fluid characterized by a density and a pressure. Taking into consideration, however, the assumption that the universe began in a singular state, it is found hard to understand why the universe is so nearly homogeneous and isotropic at present for a singularity represents a breakdown of physical laws, and the initial singularity cannot, therefore, predetermine the subsequent symmetries of the universe. The present investigation has the objective to find a way of avoiding this initial singularity, i.e., to look for a cosmological model without the big bang. The idea is proposed that there exists a limiting density of matter of the order of magnitude of the Planck density, and that this was the density of matter at the moment at which the universe began to expand
One interpretation for both Quantum Mechanics and General Relativity
Energy Technology Data Exchange (ETDEWEB)
Halewijn, Ewoud
2014-07-01
In reconciling General Relativity with Quantum Mechanics, it is challenging to resolve the combined mathematical equations and to find an interpretation that makes sense ontologically. Such an interpretation has been developed by quantizing descriptive components in both the theories and other views. The resulting micro-components have been re-integrated within the scope of known gaps between science and 'the real world'. The odd peculiarities in these theories have been made look 'normal' by fully untraditionally answering fundamental questions. The interpretation is suggesting that we define time as a discrete operator and its eigenvalues as constraints on space-time manifolds, in order to reconcile the mathematical equations. Outside the mathematical arena we suggest reconsidering the concepts of Black Holes, the Big Bang, the epistemological problem of perception in philosophy and the supposed clash between scientific and the spiritual worldviews. It is concluded that developing one consistent ontological interpretation for both theorie is possible. It is a weird story, but it is making powerful suggestions for reviewing some of our fundamental convictions.
Cosmology in time asymmetric extensions of general relativity
International Nuclear Information System (INIS)
Leon, Genly; Saridakis, Emmanuel N.
2015-01-01
We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a way that the algebra of constraints and local physics remain unchanged. Nevertheless, at cosmological scales these new terms can have significant effects that can alter the universe evolution, both at early and late times, and the freedom in the choice of the involved modification function makes the scenario able to produce a huge class of cosmological behaviors. For basic ansatzes of modification, we perform a detailed dynamical analysis, extracting the stable late-time solutions. Amongst others, we find that the universe can result in dark-energy dominated, accelerating solutions, even in the absence of an explicit cosmological constant, in which the dark energy can be quintessence-like, phantom-like, or behave as an effective cosmological constant. Moreover, it can result to matter-domination, or to a Big Rip, or experience the sequence from matter to dark energy domination. Additionally, in the case of closed curvature, the universe may experience a cosmological bounce or turnaround, or even cyclic behavior. Finally, these scenarios can easily satisfy the observational and phenomenological requirements. Hence, time asymmetric cosmology can be a good candidate for the description of the universe
OPTIS - A satellite test of Special and General Relativity
Dittus, H.; Lämmerzahl, C.; Peters, A.; Schiller, S.
OPTIS has been proposed as a small satellite platform in a high elliptical orbit (apogee 40,000 km, perigee 10,000 km) and is designed for high precision tests of foundations of Special and General Relativity. The experimental set-up consists of two ultrastable Nd:YAG lasers, two crossed optical resonators (monolithic cavities), an atomic clock, and an optical comb generator. OPTIS enables (1) a Michelson- Morley experiment to test the isotropy of light propagation (constancy of light speed, dc/c) with an accuracy of 1 part in 101 8 , (2) a Kennedey-Thorndike experiment to measure the independence of the light speed from the velocity of the laboratory in the order of 1 part in 101 6 , and (3) a test of the gravitational red shift by comparing the atomic clock and an optical clock on a precision level of 1 part in 104 . To avoid any influence from atmospheric drag, solar radiation, or earth albedo, the satellite needs drag free control, to depress the residual acceleration down to 10-14 m/s 2 in the frequency range between 100 to 1,000 Hz, and thermal control to stabilize the cavity temperature variation, dT/T, to 1 part in 107 during 100 s and to 1 part in 105 during 1 orbit.
International Nuclear Information System (INIS)
Kopeikin, Sergei M
2004-01-01
gravitational interaction c g . The Einstein equations are solved in terms of the Lienard-Wiechert tensor potentials which are used for integrating the light-ray propagation equations. An exact analytic expression for the relativistic time delay in the propagation of a radio wave from a quasar to an observer is calculated under the assumption that the light-ray deflecting bodies move with constant velocities. A post-Newtonian expansion of the time delay proves that in general relativity the time delay is affected by the speed of gravity already to the first order in 1/c g beyond the leading (static) Shapiro term. We conclude that recent measurements of the propagation of the quasar's radio signal past Jupiter are directly sensitive to the time-dependent effect from the geometric sector of general relativity which is proportional to the speed of propagation of gravity c g but not the speed of light. It provides a first confirmative measurement of the fundamental speed c of the Einstein general principle of relativity for gravitational field. A comparative analysis of our formulation with the alternative interpretations of the experiment given by other authors is provided
Gravity, black holes and the very early Universe an introduction to general relativity and cosmology
Chow, Tai L
2008-01-01
In the early 1900s, Albert Einstein formulated two theories that would forever change the landscape of physics: the Special Theory of Relativity and the General Theory of Relativity. By 1925, quantum mechanics had been born out of the dissection of these two theories, and shortly after that, relativistic quantum field theory. We now had in place some important ties between the laws of physics and the types of particle interactions the new physics was uncovering. Gravity is one of the four types of forces that are found throughout the universe. In fact, although it is a relatively weak force, it operates at huge distances, and so must be accounted for in any cosmological system. Unfortunately, gravity continues to defy our neat categorization of how all the forces in nature work together. Professor Tai Chow, from the California State University at Stanislaus in Turlock, lays out for us the basic ideas of Einstein, including his law of gravitation, explains the physics behind black holes, and weaves into this a...
International Nuclear Information System (INIS)
Shibata, Masaru; Sekiguchi, Yu-ichirou
2004-01-01
Axisymmetric numerical simulations of rotating stellar core collapse to a neutron star are performed in the framework of full general relativity. The so-called Cartoon method, in which the Einstein field equations are solved in Cartesian coordinates and the axisymmetric condition is imposed around the y=0 plane, is adopted. The hydrodynamic equations are solved in cylindrical coordinates (on the y=0 plane in Cartesian coordinates) using a high-resolution shock-capturing scheme with maximum grid size (2500,2500). A parametric equation of state is adopted to model collapsing stellar cores and neutron stars following Dimmelmeier, Font, and Mueller. It is found that the evolution of the central density during the collapse, bounce, and formation of protoneutron stars agrees well with that in the work of Dimmelmeier, Font, and Mueller in which an approximate general relativistic formulation is adopted. This indicates that such an approximation is appropriate for following axisymmetric stellar core collapses and the subsequent formation of protoneutron stars. Gravitational waves are computed using a quadrupole formula. It is found that the waveforms are qualitatively in good agreement with those by Dimmelmeier, Font, and Mueller. However, quantitatively, two waveforms do not agree well. The possible reasons for the disagreement are discussed
Energy Technology Data Exchange (ETDEWEB)
Yang, Jae-Ho; Kim, Sun-Young; Shin, Im-Hee [Catholic Univ. of Daegu, School of Medicine, Dept. of Pharmacology/Toxicology, Daegu (Korea); Kannan, K. [Wardsworth Center, New York State Dept. of Health and Dept. of Env. Health and Tox., SUNY, Albany, NY (United States)
2004-09-15
Perfluorooctanesulfonate (PFOS) was found to be widespread in human populations and wildlife Major applications of these POSF-based products have included surfactants in: specialty paper and packaging products, carpet, upholstery, and textile products and in certain insecticide formulation. Depending on the specific functional derivatization or the degree of polymerization, such POSF based products may degrade or metabolize to PFOS, a stable and persistent end product that has the potential to bioaccumulate in the food chain. The mechanisms and pathways leading to the presence of PFOS in human blood are not well characterized but likely involve environmental and dietary exposure to PFOS or to precursor molecules of PFOS. PFOS and related perfluorinated compounds have recently been detected at low parts per billion (nanogram per milliliter) concentrations in the general population from 10 different countries including Korea. In the present report, the levels of perfluoroalkylated compounds in the general population from Korea were analyzed with respect to occupation, smoking status, sex, age and socio-economic status. The degree of association between the four target fluorochemicals measured in this study (PFOS, PFHxS, PFOA, and PFOSA) were also analyzed by linear regression to determine the potential association between their sources of exposure.
Lagrangian dynamics of spinning particles and polarized media in general relativity
International Nuclear Information System (INIS)
Bailey, Ian.
1980-01-01
The dynamic laws governing spinning multipole test particles and polarized media with internal spin are derived from both variational principles and the multipole formalism of extended bodies. The general form of the Lagrangian equations of motion is derived for a spinning multipole particle in given external fields. The author then considers the dynamics of a continuous medium with internal spin and multipole structure. From a four-dimensional action integral the field equations relating to fields generated by the medium to its bulk properties are derived, together with the balance laws expressing conservation of total four-momentum and spin. A natural splitting of the total energy-momentum tensor into matter and field parts is adopted that leads to a generalized Minkowski electromagnetic energy tensor. In both the electromagnetic and the gravitational field equations the source terms contain polarization contributions. It is shown that the multipole formalism may be used to formulate the same equations of motion, balance laws and decomposition of total energy-momentum as those resulting from variational principles
Probing General Relativity and New Physics with Lunar Laser Ranging
Energy Technology Data Exchange (ETDEWEB)
Dell' Agnello, S. [Laboratori Nazionali di Frascati (LNF) dell' INFN, Frascati, Rome (Italy); Maiello, M., E-mail: mauro.maiello@lnf.infn.it [Laboratori Nazionali di Frascati (LNF) dell' INFN, Frascati, Rome (Italy); Currie, D.G. [University of Maryland (UMD), College Park, MD (United States); Boni, A.; Berardi, S.; Cantone, C.; Delle Monache, G.O.; Intaglietta, N.; Lops, C.; Garattini, M.; Martini, M.; Patrizi, G.; Porcelli, L.; Tibuzzi, M. [Laboratori Nazionali di Frascati (LNF) dell' INFN, Frascati, Rome (Italy); Vittori, R. [Aeronautica Militare Italiana (AMI), Rome (Italy); Agenzia Spaziale Italiana (ASI), Rome (Italy); Bianco, G. [ASI-Centro di Geodesia Spaziale, Matera (Italy); Coradini, A. [INAF-Istituto di Fisica dello Spazio Interplanetario (IFSI), Via Fosso del Cavaliere 100, 00133 Rome (Italy); Dionisio, C. [Rheinmetall Italia S.p.A., Via Affile 102, 00131 Rome (Italy); March, R. [INFN-LNF and CNR-Istituto per le Applicazioni del Calcolo (IAC), Viale del Policlinico 137, 00161 Rome (Italy); Bellettini, G. [INFN-LNF and Department of Mathematics, University of Rome ' Tor Vergata' , Via della Ricerca Scientifica, 00133 Rome (Italy); and others
2012-11-11
Over the past 40 years, Lunar Laser Ranging (LLR, developed by the Univ. of Maryland (PI) and INFN-LNF (Co-PI)) to the Apollo Cube Corner Retroreflector (CCR) arrays have supplied almost all the significant tests of General Relativity (Currie et al., 2009 [12]). LLR can evaluate the PPN (Post Newtonian Parameters), addressing this way both the possible changes in the gravitational constant and the self-energy properties of the gravitational field. In addition, the LLR has provided significant information on the composition and origin of the Moon. This is the only Apollo experiment that is still in operation. Initially the Apollo LLR arrays contributed a negligible fraction of the ranging error budget. Over the decades, the ranging capabilities of the ground stations have improved by more than two orders of magnitude. Now, because of the lunar librations, the existing Apollo retroreflector arrays contribute a significant fraction of the limiting errors in the range measurements. We built a new experimental apparatus (the 'Satellite/Lunar Laser Ranging Characterization Facility', SCF) and created a new test procedure (the SCF-Test) to characterize and model the detailed thermal behavior and the optical performance of cube corner laser retroreflectors in space for industrial and scientific applications (Dell'Agnello et al., 2011 [13]). Our key experimental innovation is the concurrent measurement and modeling of the optical Far Field Diffraction Pattern (FFDP) and the temperature distribution of the SLR retroreflector payload under thermal conditions produced with a close-match solar simulator. The apparatus includes infrared cameras for non-invasive thermometry, thermal control and real-time movement of the payload to experimentally simulate satellite orientation on orbit with respect to both solar illumination and laser interrogation beams. These unique capabilities provide experimental validation of the space segment for SLR and Lunar Laser Ranging
PLANCK, the Satellite: a New Experimental Test of General Relativity
Directory of Open Access Journals (Sweden)
Rabounski D.
2008-04-01
Full Text Available If the origin of a microwave background (EMB is the Earth, what would be its density and associated dipole anisotropy measured at different altitudes from the surface of the Earth? The mathematical methods of the General Theory of Relativity are applied herein to answer these questions. The density of the EMB is answered by means of Einstein's equations for the electromagnetic field of the Earth. The dipole anisotropy, which is due to the rapid motion of the source (the Earth in the weak intergalactic field, is analysed by using the geodesic equations for light-like particles (photons, which are mediators for electromagnetic radiation. It is shown that the EMB decreases with altitude so that the density of its energy at the altitude of the COBE orbit (900km is 0.68 times less than that at the altitude of a U2 aeroplane (25km. Furthermore, the density at the 2nd Lagrange point (1.5 million km, the position of the WMAP and PLANCK satellites should be only 10$^{-7}$ of the value detected by a U2 aeroplane or at the COBE orbit. The dipole anisotropy of the EMB doesn't depend on altitude from the surface of the Earth, it should be the same irrespective of the altitude at which measurements are taken. This result is in support to the experimental and observational analysis conducted by P.-M.Robitaille, according to which the 2.7K microwave background, first observed by Penzias and Wilson, is not of cosmic origin, but of the Earth, and is generated by the oceans. WMAP indicated the same anisotropy of the microwave background at the 2nd Lagrange point that near the Earth. Therefore when PLANCK, which is planned on July, 2008, will manifest the 2.7K monopole microwave signal deceased at the 2nd Langrange point, it will be a new experimental verification of Einstein's theory.
Probing modifications of general relativity using current cosmological observations
International Nuclear Information System (INIS)
Zhao Gongbo; Bacon, David J.; Koyama, Kazuya; Nichol, Robert C.; Song, Yong-Seon; Giannantonio, Tommaso; Pogosian, Levon; Silvestri, Alessandra
2010-01-01
We test general relativity (GR) using current cosmological data: the CMB from WMAP5 [E. Komatsu et al. (WMAP Collaboration), Astrophys. J. Suppl. Ser. 180, 330 (2009)], the integrated Sachs-Wolfe (ISW) effect from the cross correlation of the CMB with six galaxy catalogs [T. Giannantonio et al., Phys. Rev. D 77, 123520 (2008)], a compilation of supernovae (SNe) type Ia including the latest Sloan Digital Sky Survey SNe [R. Kessler et al., Astrophys. J. Suppl. Ser. 185, 32 (2009).], and part of the weak lensing (WL) data from the Canada-Franco-Hawaii Telescope Legacy Survey [L. Fu et al., Astron. Astrophys. 479, 9 (2008); M. Kilbinger et al., Astron. Astrophys. 497, 677 (2009).] that probe linear and mildly nonlinear scales. We first test a model in which the effective Newtonian constant μ and the ratio of the two gravitational potentials, η, transit from the GR value to another constant at late times; in this case, we find that GR is fully consistent with the combined data. The strongest constraint comes from the ISW effect which would arise from this gravitational transition; the observed ISW signal imposes a tight constraint on a combination of μ and η that characterizes the lensing potential. Next, we consider four pixels in time and space for each function μ and η, and perform a principal component analysis, finding that seven of the resulting eight eigenmodes are consistent with GR within the errors. Only one eigenmode shows a 2σ deviation from the GR prediction, which is likely to be due to a systematic effect. However, the detection of such a deviation demonstrates the power of our time- and scale-dependent principal component analysis methodology when combining observations of structure formation and expansion history to test GR.
PLANCK, the Satellite: a New Experimental Test of General Relativity
Directory of Open Access Journals (Sweden)
Borissova L.
2008-04-01
Full Text Available If the origin of a microwave background (EMB is the Earth, what would be its density and associated dipole anisotropy measured at different altitudes from the surface of the Earth? The mathematical methods of the General Theory of Relativity are applied herein to answer these questions. The density of the EMB is answered by means of Einstein’s equations for the electromagnetic field of the Earth. The dipole anisotropy, which is due to the rapid motion of the source (the Earth in the weak intergalactic field, is analysed by using the geodesic equations for light-like particles (photons, which are mediators for electromagnetic radiation. It is shown that the EMB decreases with altitude so that the density of its energy at the altitude of the COBE orbit (900km is 0.68 times less than that at the altitude of a U2 aeroplane (25 km. Furthermore, the density at the 2nd Lagrange point (1.5 million km, the position of the WMAP and PLANCK satellites should be only 1E-7 of the value detected by a U2 aeroplane or at the COBE orbit. The dipole anisotropy of the EMB doesn’t depend on altitude from the surface of the Earth, it should be the same irrespective of the altitude at which measurements are taken. This result is in support to the experimental and observational analysis conducted by P.-M. Robitaille, according to which the 2.7 K microwave background, first observed by Penzias and Wilson, is not of cosmic origin, but of the Earth, and is generated by the oceans. WMAP indicated the same anisotropy of the microwave background at the 2nd Lagrange point that near the Earth. Therefore when PLANCK, which is planned on July, 2008, will manifest the 2.7 K monopole microwave signal deceased at the 2nd Langrange point, it will be a new experimental verification of Einstein’s theory.
Disseminating General Relativity for 21st century astronomy
Crosta, Mariateresa
2015-08-01
The talk aims to present two outreach projects - initially developed for the ESA Gaia satellite, a multidisciplinary mission launched on December 19, 2013 - available to the OAD community: NeST and "The Meaning of Light".NeST is an interactive educational tool, that displays how the theory of GR rules the Universe, it creates a performance physically "belonging" to the exhibition space and moving through it, materializing what J.A. Wheeler said "mass tells space-time how to curve, and space-time tells mass how to move"."The Meaning of Light" is a short motion comics, part of an extensive outreach program called "The History of Photons" whose main theme is the story of a beam of stellar photons that, after leaving the progenitor star, propagates through the Universe and, once intercepted come into contact with a team of scientists: here begins their adventure to be taken "back" home and in doing so the scientists, and the spectators, are driven to discover the wonders of which the light are the bearers.The description of the journey of the photons becomes, therefore, an opportunity to easily tell the fascinating topics of Astrophysics and General Relativity, i.e. the complexity and the infinite beauty of the Universe in which we live.For this movie a new theme song was produced, "Singing the Stars", whose refrain (Oh Be A Fine Girl / Guy Kiss Me Little Thing, Yeah) adds to the famous mnemonic for stellar classification (OBAFGKM) the new stellar types LTY discovered in recent years.
Kersting, Magdalena; Henriksen, Ellen Karoline; Bøe, Maria Vetleseter; Angell, Carl
2018-06-01
Because of its abstract nature, Albert Einstein's theory of general relativity is rarely present in school physics curricula. Although the educational community has started to investigate ways of bringing general relativity to classrooms, field-tested educational material is rare. Employing the model of educational reconstruction, we present a collaborative online learning environment that was introduced to final year students (18-19 years old) in six Norwegian upper secondary physics classrooms. Design-based research methods guided the development of the learning resources, which were based on a sociocultural view of learning and a historical-philosophical approach to teaching general relativity. To characterize students' learning from and interaction with the learning environment we analyzed focus group interviews and students' oral and written responses to assigned problems and discussion tasks. Our findings show how design choices on different levels can support or hinder understanding of general relativity, leading to the formulation of design principles that help to foster qualitative understanding and encourage collaborative learning. The results indicate that upper secondary students can obtain a qualitative understanding of general relativity when provided with appropriately designed learning resources and sufficient scaffolding of learning through interaction with teacher and peers.
Relation of a unified quantum field theory of spinors to the structure of general relativity
International Nuclear Information System (INIS)
Kober, Martin
2009-01-01
Based on a unified quantum field theory of spinors assumed to describe all matter fields and their interactions we construct the space-time structure of general relativity according to a general connection within the corresponding spinor space. The tetrad field and the corresponding metric field are composed from a space-time dependent basis of spinors within the internal space of the fundamental matter field. Similar to twistor theory the Minkowski signature of the space-time metric is related to this spinor nature of elementary matter, if we assume the spinor space to be endowed with a symplectic structure. The equivalence principle and the property of background independence arise from the fact that all elementary fields are composed from the fundamental spinor field. This means that the structure of space-time according to general relativity seems to be a consequence of a fundamental theory of matter fields and not a presupposition as in the usual setting of relativistic quantum field theories.
Univalence Conditions Related to a General Integral Operator
Directory of Open Access Journals (Sweden)
Nicoleta Breaz
2012-01-01
Full Text Available We consider a general integral operator based on two types of analytic functions, namely, regular functions and, respectively, functions having a positive real part. Some univalence conditions for this integral operator are obtained.
Application of the dynamical interpretation of general relativity
International Nuclear Information System (INIS)
Deumens, E.
1981-01-01
The paper argues that the gravitational field seen in the fully dynamical way, described here, is a useful tool for understanding some fundamental results in a coherent general relativistic way. (author)
Energy Technology Data Exchange (ETDEWEB)
Kober, Martin
2010-07-01
The specific content of the present thesis is presented in the following way. First the most important contents of quantum theory and general relativity theory are presented. In connection with the general relativity theory the mathematical property of the diffeomorphism invariance plays the deciding role, while concerning the quantum theory starting from the Copenhagen interpretation first the measurement problem is treated, before basing on the analysis of concrete phenomena and the mathematical apparatus of quantum theory the nonlocality is brought into focus as an important property. This means that both theories suggest a relationalistic view of the nature of the space. This analysis of the theoretical foundations of quantum theory and general relativity theory in relation to the nature of the space obtains only under inclusion of Kant's philosophy and his analysis of the terms space and time as fundamental forms of perception its full persuasive power. Then von Weizsaeckers quantum theory of the ur-alternatives is presented. Finally attempts are made to apply the obtained knowledge to the question of the quantum-theoretical formulation of general relativity theory.
International Nuclear Information System (INIS)
Gomis, L; Diedhiou, I; Tall, M S; Diallo, S; Diatta, C S; Niassy, B
2007-01-01
The quadrupole and monopole generalized oscillator strengths (GOS) as a function of momentum transfer are calculated for the 2p-3p and 2p-4p transitions of the neon atom using the analytical Hartree-Fock (HF) wavefunctions for the ground-state and the wavefunctions for the excited states which are obtained numerically from the modified HF Slater equation. Calculations are carried out by using the HF method and random phase approximation with exchange in the velocity formulation. The positions and the number of the extrema in the GOS have received particular attention in the evaluation. Our calculated monopole GOS of 2p-3p transition in velocity form reveals one maximum located between the experimental and theoretical results of other authors. The disagreement between our first maximum of the quadrupole GOS 2p-3p transition with the experimental and other theoretical ones is unimportant. The extrema of the monopole and quadrupole GOS of 2p-4p transition are given in this paper. The results of velocity form study also show that the electron correlation effects are important around the maxima and are found to influence the positions of the extrema insignificantly
Quantum mechanics in general relativity and its special - relativistic limit
International Nuclear Information System (INIS)
Tagirov, Eh.A.
1998-01-01
Quantum mechanics of a neutral point-like particle in the general Riemannian space-time is constructed starting with the general Fock representation of the quantum scalar field. The known ambiguity of the representation is removed by the requirement that the quasi-one-particle wave functions in configurational space should admit the Born probabilistic interpretation after a transformation, generally nonlocal, and therefore may be considered as the one-particle wave functions. Operators of momentum and spatial position of a particle acting in the space of these transformed wave functions are deduced consecutively from basic naturally defined operators of the observables in the Fock space. They coincide with the canonical ones only in the case of the infinite velocity of light. In particular, even in the Minkowski space-time and inertial frames of reference , the operators of curvilinear coordinates do not commute
Large-scale structure observables in general relativity
International Nuclear Information System (INIS)
Jeong, Donghui; Schmidt, Fabian
2015-01-01
We review recent studies that rigorously define several key observables of the large-scale structure of the Universe in a general relativistic context. Specifically, we consider (i) redshift perturbation of cosmic clock events; (ii) distortion of cosmic rulers, including weak lensing shear and magnification; and (iii) observed number density of tracers of the large-scale structure. We provide covariant and gauge-invariant expressions of these observables. Our expressions are given for a linearly perturbed flat Friedmann–Robertson–Walker metric including scalar, vector, and tensor metric perturbations. While we restrict ourselves to linear order in perturbation theory, the approach can be straightforwardly generalized to higher order. (paper)
Unification of General Relativity with Quantum Field Theory
International Nuclear Information System (INIS)
Ni Jun
2011-01-01
In the frame of quantum field theory, instead of using the action principle, we deduce the Einstein equation from purely the general covariant principle and the homogeneity of spacetime. The Einstein equation is shown to be the gauge equation to guarantee the local symmetry of spacetime translation. Gravity is an apparent force due to the curvature of spacetime resulted from the conservation of energy-momentum. In the action of quantum field theory, only electroweak-strong interactions should be considered with the curved spacetime metric determined by the Einstein equation. (general)
Sun, Guo-Hua; Dong, Shi-Hai
2015-06-01
Based on a Hamiltonian identity, we study one-dimensional generalized hypervirial theorem, Blanchard-like (non-diagonal case) and Kramers' (diagonal case) recurrence relations for arbitrary xκ which is independent of the central potential V(x). Some significant results in diagonal case are obtained for special κ in xκ (κ ≥ 2). In particular, we find the orthogonal relation = δn1n2 (κ = 0), = (En1 - En2)2 (κ = 1), En = + (κ = 2) and -4En + + 4 = 0 (κ = 3). The latter two formulas can be used directly to calculate the energy levels. We present useful explicit relations for some well known physical potentials without requiring the energy spectra of quantum system. Supported in part by Project 20150964-SIP-IPN, COFAA-IPN, Mexico
Relativity: An Introduction to Special and General Relativity, 3rd edn
International Nuclear Information System (INIS)
Rendall, Alan
2004-01-01
This book is concerned with mathematical topics related to general relativity. Chapters 1-6 are expositions of a number of parts of mathematics which are important for relativists. The main subjects covered are linear algebra, general topology, manifolds, Lie groups and, in particular detail, the Lorentz group. Chapters 7-13 analyse aspects of the geometrical structure of spacetimes. They focus on symmetries of various types and on properties of curvature. Subjects covered include the Petrov classification, holonomy groups, the relation between metric and curvature, affine vector fields, conformal symmetries, projective symmetries and curvature collineations. This part of the book is a treatise on the (mainly local) geometry of four-dimensional Lorentz manifolds, with attention to energy-momentum tensors of interest in general relativity. In the first six chapters the author has concentrated on giving definitions and statements of theorems, the proofs being left to the references that are quoted. He has clearly put much effort into producing a very smooth exposition which is easy to follow and has succeeded in giving us a readable and informative account of the mathematics covered. At the same time mathematical rigour is strictly observed. He also takes the time to carefully discuss many of the subtleties which arise. This part of the book has the character of a textbook suitable for students of general relativity but experienced researchers will also find it a useful reference and are likely to come across interesting facts they have not met elsewhere. The remaining chapters are more like a research monograph and are influenced by the author's own research interests. More proofs are included. Much of the material in this part will be of interest to a narrower audience of relativists than that of the first part. It should, however, be of interest to those working on exact solutions of the Einstein equations and related topics. It is also the case that most
Santos, Danyelle K. F.; Resende, Ana H. M.; de Almeida, Darne G.; Soares da Silva, Rita de Cássia F.; Rufino, Raquel D.; Luna, Juliana M.; Banat, Ibrahim M.; Sarubbo, Leonie A.
2017-01-01
The aim of the present study was to investigate the potential application of the biosurfactant from Candida lipolytica grown in low-cost substrates, which has previously been produced and characterized under optimized conditions as an adjunct material to enhance the remediation processes of hydrophobic pollutants and heavy metals generated by the oil industry and propose the formulation of a safe and stable remediation agent. In tests carried out with seawater, the crude biosurfactant demonstrated 80% oil spreading efficiency. The dispersion rate was 50% for the biosurfactant at a concentration twice that of the CMC. The biosurfactant removed 70% of motor oil from contaminated cotton cloth in detergency tests. The crude biosurfactant also removed 30–40% of Cu and Pb from standard sand, while the isolated biosurfactant removed ~30% of the heavy metals. The conductivity of solutions containing Cd and Pb was sharply reduced after biosurfactants' addition. A product was prepared through adding 0.2% potassium sorbate as preservative and tested over 120 days. The formulated biosurfactant was analyzed for emulsification and surface tension under different pH values, temperatures, and salt concentrations and tested for toxicity against the fish Poecilia vivipara. The results showed that the formulation had no toxicity and did not cause significant changes in the tensoactive capacity of the biomolecule while maintaining activity demonstrating suitability for potential future commercial product formulation. PMID:28507538
Directory of Open Access Journals (Sweden)
Leonie A. Sarubbo
2017-05-01
Full Text Available The aim of the present study was to investigate the potential application of the biosurfactant from Candida lipolytica grown in low-cost substrates, which has previously been produced and characterized under optimized conditions as an adjunct material to enhance the remediation processes of hydrophobic pollutants and heavy metals generated by the oil industry and propose the formulation of a safe and stable remediation agent. In tests carried out with seawater, the crude biosurfactant demonstrated 80% oil spreading efficiency. The dispersion rate was 50% for the biosurfactant at a concentration twice that of the CMC. The biosurfactant removed 70% of motor oil from contaminated cotton cloth in detergency tests. The crude biosurfactant also removed 30–40% of Cu and Pb from standard sand, while the isolated biosurfactant removed ~30% of the heavy metals. The conductivity of solutions containing Cd and Pb was sharply reduced after biosurfactants' addition. A product was prepared through adding 0.2% potassium sorbate as preservative and tested over 120 days. The formulated biosurfactant was analyzed for emulsification and surface tension under different pH values, temperatures, and salt concentrations and tested for toxicity against the fish Poecilia vivipara. The results showed that the formulation had no toxicity and did not cause significant changes in the tensoactive capacity of the biomolecule while maintaining activity demonstrating suitability for potential future commercial product formulation.
Einstein's Unification: General Relativity and the Quest for Mathematical Naturalness
van Dongen, J.A.E.F.
2002-01-01
The aim of the thesis has been to understand Einstein's development and see the historical coherence in his later attitude in physics. The lesson we learned has been straightforward: the key that unlocks the later Einstein lies in the road by which he arrived at the field equations of general
Bianchi type IX string cosmological model in general relativity
Indian Academy of Sciences (India)
Cosmic strings arise during phase transitions after the big-bang explosion as the temperature goes down below some critical temperature [1–3]. These strings have stress energy and couple in a simple way to the gravitational field. The general relativistic formalism of cosmic strings is due to Letelier [4,5]. Stachel [6] has ...
An introduction to the geometry of singularities on general relativity
International Nuclear Information System (INIS)
Canarutto, D.
1988-01-01
The aim of this paper is the introduction of many ideas in differential geometry by adopting an abstract and general framework. Such a clearness permits to obtain a powerful and simple theory of connection on fibred manifolds allowing a clearer understanding and easier handling (C.P.)
Charged Analogues of Henning Knutsen Type Solutions in General Relativity
Gupta, Y. K.; Kumar, Sachin; Pratibha
2011-11-01
In the present article, we have found charged analogues of Henning Knutsen's interior solutions which join smoothly to the Reissner-Nordstrom metric at the pressure free interface. The solutions are singularity free and analyzed numerically with respect to pressure, energy-density and charge-density in details. The solutions so obtained also present the generalization of A.L. Mehra's solutions.
The Generals’ Revolt and Civil-Military Relations
2009-05-11
freedom of speech .1 In America, where freedom of speech is an inalienable right and civilian control of the military is a...military. 2 This paper will examine the Generals’ Revolt as well as review legal restrictions on the freedom of speech of retired officers. It will also...Spring of 2006 does not correct the problem, nor does it bring comfort to the families who lost servicemembers in Iraq. 8 Freedom of Speech
Will-Nordtvedt PPN formalism applied to renormalization group extensions of general relativity
Toniato, Júnior D.; Rodrigues, Davi C.; de Almeida, Álefe O. F.; Bertini, Nicolas
2017-09-01
We apply the full Will-Nordtvedt version of the parametrized post-Newtonian (PPN) formalism to a class of general relativity extensions that are based on nontrivial renormalization group (RG) effects at large scales. We focus on a class of models in which the gravitational coupling constant G is correlated with the Newtonian potential. A previous PPN analysis considered a specific realization of the RG effects, and only within the Eddington-Robertson-Schiff version of the PPN formalism, which is a less complete and robust PPN formulation. Here we find stronger, more precise bounds, and with less assumptions. We also consider the external potential effect (EPE), which is an effect that is intrinsic to this framework and depends on the system environment (it has some qualitative similarities to the screening mechanisms of modified gravity theories). We find a single particular RG realization that is not affected by the EPE. Some physical systems have been pointed out as candidates for measuring the possible RG effects in gravity at large scales; for any of them the Solar System bounds need to be considered.
Relation of gauge formalisms for pulsations of general-relativistic stellar models
International Nuclear Information System (INIS)
Price, R.H.; Ipser, J.R.
1991-01-01
There have been two recent reformulations of the equations for even-parity perturbations of general-relativistic stellar models, in both of which fluid perturbation variables are absent in the final set of equations. The recent reformulation by Chandrasekhar and Ferrari uses the diagonal coordinate gauge and leads to a fifth-order system of differential equations; we have recently presented a reformulation, based on the Regge-Wheeler coordinate gauge, which leads to a fourth-order system. The difference in the orders is similar to that for perturbations of Schwarzschild and of Reissner-Nordstroem black holes; in both cases the diagonal-gauge formulation led to a system one degree higher than that for equations based on the Regge-Wheeler gauge. For perturbations of holes, however, the equations could be reduced by one degree. We show that this is the case also for the Chandrasekhar-Ferrari equations for stellar perturbations. More important, we show that the extra degree of freedom, in all descriptions based on the diagonal gauge, is due to the fact that the diagonal gauge is an incomplete constraint on coordinates; a one degree of freedom set of gauge transformations can be made within the diagonal gauge. This previously unnoticed degree of freedom is responsible for the extra degree of freedom in the Chandrasekhar-Ferrari equations, and the related black-hole equations. It also provides an a priori solution with which those equations can be reduced
Directory of Open Access Journals (Sweden)
Rami Ahmad El-Nabulsi
2015-08-01
Full Text Available Recently, non-standard Lagrangians have gained a growing importance in theoretical physics and in the theory of non-linear differential equations. However, their formulations and implications in general relativity are still in their infancies despite some advances in contemporary cosmology. The main aim of this paper is to fill the gap. Though non-standard Lagrangians may be defined by a multitude form, in this paper, we considered the exponential type. One basic feature of exponential non-standard Lagrangians concerns the modified Euler-Lagrange equation obtained from the standard variational analysis. Accordingly, when applied to spacetime geometries, one unsurprisingly expects modified geodesic equations. However, when taking into account the time-like paths parameterization constraint, remarkably, it was observed that mutually discrete gravity and discrete spacetime emerge in the theory. Two different independent cases were obtained: A geometrical manifold with new spacetime coordinates augmented by a metric signature change and a geometrical manifold characterized by a discretized spacetime metric. Both cases give raise to Einstein’s field equations yet the gravity is discretized and originated from “spacetime discreteness”. A number of mathematical and physical implications of these results were discussed though this paper and perspectives are given accordingly.
Indefinite-metric quantum field theory of general relativity, 6
International Nuclear Information System (INIS)
Nakanishi, Noboru
1979-01-01
The canonical commutation relations are analyzed in detail in the indefinite-metric quantum field theory of gravity based on the vierbein formalism. It is explicitly verified that the BRS charge, the local-Lorentz-BRS charge and the Poincare generators satisfy the expected commutation relations. (author)
Testing General Relativity Using Gravitational-Wave Observations
Indian Academy of Sciences (India)
Coalescence of binary black holes. 4. Post-Newtonian theory. BH perturbation theory. Numerical. Relativity. Inspiral. Merger Ring down. (Pic. K. Thorne). First opportunity to test Einstein's theory in the highly relativistic regime.
Orbits in general relativity: the Jacobian elliptic function
Energy Technology Data Exchange (ETDEWEB)
Miro Rodriguez, C
1987-03-11
The Jacobian elliptic functions are applied to the motion of nonzero-rest-mass particles in the Schwarzschild geometry. The bound and unbound trajectories are analysed together with their classical and special-relativity limits.
Nonextensive kinetic theory and H-theorem in general relativity
Santos, A. P.; Silva, R.; Alcaniz, J. S.; Lima, J. A. S.
2017-11-01
The nonextensive kinetic theory for degenerate quantum gases is discussed in the general relativistic framework. By incorporating nonadditive modifications in the collisional term of the relativistic Boltzmann equation and entropy current, it is shown that Tsallis entropic framework satisfies a H-theorem in the presence of gravitational fields. Consistency with the 2nd law of thermodynamics is obtained only whether the entropic q-parameter lies in the interval q ∈ [ 0 , 2 ] . As occurs in the absence of gravitational fields, it is also proved that the local collisional equilibrium is described by the extended Bose-Einstein (Fermi-Dirac) q-distributions.
Directory of Open Access Journals (Sweden)
Akimov Pavel Alekseevich
2012-10-01
Full Text Available The proposed paper covers the operator-related formulation of the eigenvalue problem of analysis of a three-dimensional structure that has piecewise-constant physical and geometrical parameters alongside the so-called basic direction within the framework of a discrete-continual approach (a discrete-continual finite element method, a discrete-continual variation method. Generally, discrete-continual formulations represent contemporary mathematical models that become available for computer implementation. They make it possible for a researcher to consider the boundary effects whenever particular components of the solution represent rapidly varying functions. Another feature of discrete-continual methods is the absence of any limitations imposed on lengths of structures. The three-dimensional problem of elasticity is used as the design model of a structure. In accordance with the so-called method of extended domain, the domain in question is embordered by an extended one of an arbitrary shape. At the stage of numerical implementation, relative key features of discrete-continual methods include convenient mathematical formulas, effective computational patterns and algorithms, simple data processing, etc. The authors present their formulation of the problem in question for an isotropic medium with allowance for supports restrained by elastic elements while standard boundary conditions are also taken into consideration.
Generalized Ehrenfest Relations, Deformation Quantization, and the Geometry of Inter-model Reduction
Rosaler, Joshua
2018-03-01
This study attempts to spell out more explicitly than has been done previously the connection between two types of formal correspondence that arise in the study of quantum-classical relations: one the one hand, deformation quantization and the associated continuity between quantum and classical algebras of observables in the limit \\hbar → 0, and, on the other, a certain generalization of Ehrenfest's Theorem and the result that expectation values of position and momentum evolve approximately classically for narrow wave packet states. While deformation quantization establishes a direct continuity between the abstract algebras of quantum and classical observables, the latter result makes in-eliminable reference to the quantum and classical state spaces on which these structures act—specifically, via restriction to narrow wave packet states. Here, we describe a certain geometrical re-formulation and extension of the result that expectation values evolve approximately classically for narrow wave packet states, which relies essentially on the postulates of deformation quantization, but describes a relationship between the actions of quantum and classical algebras and groups over their respective state spaces that is non-trivially distinct from deformation quantization. The goals of the discussion are partly pedagogical in that it aims to provide a clear, explicit synthesis of known results; however, the particular synthesis offered aspires to some novelty in its emphasis on a certain general type of mathematical and physical relationship between the state spaces of different models that represent the same physical system, and in the explicitness with which it details the above-mentioned connection between quantum and classical models.
International Nuclear Information System (INIS)
Zakharov, A.V.; Singatullin, R.S.
1981-01-01
The inverse problem is solved in general relativity theory (GRT) consisting in determining the metric and potentials of an electromagnetic field by their values in the nonsingular point of the V 4 space and present functions, being the generalized momenta of a test charged particle. The Hamilton-Jacobi equation for a test charged particle in GRT is used. The general form of the generalized momentum dependence on the initial values is determined. It is noted that the inverse problem solution of dynamics in GRT contains arbitrariness which depends on the choice of the metric and potential values of the electromagnetic field in the nonsingular point [ru
9th International Conference on General Relativity and Gravitation
International Nuclear Information System (INIS)
Schmutzer, E.
1980-01-01
Volume 3 presents the abstracts of the following discussion groups: Quantization about classical background metrics (36 abstracts); Supergravity, renormalization program (8 abstracts); Classical gauge type theories of gravity (23 abstracts). 14 abstracts not related to any discussion group and 5 later submitted abstracts are also included. An alphabetic author index is given
Special relativity in general frames from particles to astrophysics
Gourgoulhon, Éric
2013-01-01
Special relativity is the basis of many fields in modern physics: particle physics, quantum field theory, high-energy astrophysics, etc. This theory is presented here by adopting a four-dimensional point of view from the start. An outstanding feature of the book is that it doesn’t restrict itself to inertial frames but considers accelerated and rotating observers. It is thus possible to treat physical effects such as the Thomas precession or the Sagnac effect in a simple yet precise manner. In the final chapters, more advanced topics like tensorial fields in spacetime, exterior calculus and relativistic hydrodynamics are addressed. In the last, brief chapter the author gives a preview of gravity and shows where it becomes incompatible with Minkowsky spacetime. Well illustrated and enriched by many historical notes, this book also presents many applications of special relativity, ranging from particle physics (accelerators, particle collisions, quark-gluon plasma) to astrophysics (relativistic jets, active g...
Indefinite-metric quantum field theory of general relativity, 15
International Nuclear Information System (INIS)
Nakanishi, Noboru
1982-01-01
In the manifestly covariant canonical formalism of quantum gravity, it is known that the equal-time commutator between a tensor field and the B field b sub(rho) is consistent with the rules of tensor analysis. Another tensorlike commutation relation is shown to exist for the equal-time commutator between a tensor and b sub(rho), but at the same time its limitation is clarified. The quantum-gravity extension of the invariant D function is defined and provied to be affine-invariant. The four-dimensional commutation relation between a tensor and b sub(rho) is investigated, and it is shown that the commutator consists of a completely tensorlike, manifestly affine-covariant part and a remainder, which is clearly distinguishable from the former. (author)
Hydrodynamics in full general relativity with conservative AMR
East, William E.; Pretorius, Frans; Stephens, Branson C.
2011-01-01
There is great interest in numerical relativity simulations involving matter due to the likelihood that binary compact objects involving neutron stars will be detected by gravitational wave observatories in the coming years, as well as to the possibility that binary compact object mergers could explain short-duration gamma-ray bursts. We present a code designed for simulations of hydrodynamics coupled to the Einstein field equations targeted toward such applications. This code has recently be...
General characteristics of relative dispersion in the ocean
Corrado, Raffaele; Lacorata, Guglielmo; Palatella, Luigi; Santoleri, Rosalia; Zambianchi, Enrico
2017-04-01
The multi-scale and nonlinear nature of the ocean dynamics dramatically affects the spreading of matter, like pollutants, marine litter, etc., of physical and chemical seawater properties, and the biological connectivity inside and among different basins. Based on the Finite-Scale Lyapunov Exponent analysis of the largest available near-surface Lagrangian data set from the Global Drifter Program, our results show that, despite the large variety of flow features, relative dispersion can ultimately be described by a few parameters common to all ocean sub-basins, at least in terms of order of magnitude. This provides valuable information to undertake Lagrangian dispersion studies by means of models and/or of observational data. Moreover, our results show that the relative dispersion rates measured at submesoscale are significantly higher than for large-scale dynamics. Auxiliary analysis of high resolution GPS-tracked drifter hourly data as well as of the drogued/undrogued status of the buoys is provided in support of our conclusions. A possible application of our study, concerning reverse drifter motion and error growth analysis, is proposed relatively to the case of the missing Malaysia Airlines MH370 aircraft.
Anaphylactic bronchospasm during general anesthesia is not related to asthma.
Gouel-Chéron, A; Neukirch, C; Aubier, B; Montravers, P; Nicaise, P; Chollet-Martin, S; Mertes, P-M; Aubier, M; Longrois, D
2015-04-01
In the general population, a history of asthma (HA) is associated with a higher risk of mortality of anaphylactic shock (AS), but it is unknown whether this association remains valid for intra-operative AS. The goal of this retrospective study was to investigate whether a HA was associated with a higher risk of bronchospasm during intra-operative AS. We analyzed 106 patients (January 2009-December 2012) with intra-operative AS: 57% of them had a confirmed IgE-mediated reaction and 27% had a HA. On logistic regression, the only factor statistically associated with bronchospasm was a neuromuscular blocking drug, with both IgE- or non-IgE-mediated reactions. These results suggest that the mechanisms of bronchospasm in AS may be different from those of asthma and that, in the presence of bronchospasm during anesthesia, AS should be considered to be the most likely cause. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Thermodynamic Product Relations for Generalized Regular Black Hole
International Nuclear Information System (INIS)
Pradhan, Parthapratim
2016-01-01
We derive thermodynamic product relations for four-parametric regular black hole (BH) solutions of the Einstein equations coupled with a nonlinear electrodynamics source. The four parameters can be described by the mass (m), charge (q), dipole moment (α), and quadrupole moment (β), respectively. We study its complete thermodynamics. We compute different thermodynamic products, that is, area product, BH temperature product, specific heat product, and Komar energy product, respectively. Furthermore, we show some complicated function of horizon areas that is indeed mass-independent and could turn out to be universal.
Bulk optic Sagnac interferometer for tests of general relativity
International Nuclear Information System (INIS)
Ranganathan, D.; Mehta, C.L.
1986-01-01
Ring laser and Sagnac interferometer gyroscopes have been suggested for a possible experiment to test metric theories of gravity. As emphasized in recent reviews, neither ring lasers nor fiber gyroscopes seem to provide the required accuracy. The same appears to be true of passive cavity resonators or nonlinear variants. The primary problem with fiber Sagnac interferometers is that the permissible power before onset or nonlinearities is quite limited (10-100 mW). Thus the SNR possible is also limited. To overcome this limitation, the authors suggest use of a bulk optic device. Specifically, the author' suggest the use of a silica block with a square cross section. Each of its faces is polished to form a segment of a sphere whose center is at the center of the opposite face. Rays originating at the center of a face and incident on the next adjacent face near its center are totally internally reflected and focused on the center of the third face in sequence. Thus the light rotates about the cavity before coming back to the point of incidence. If a light beam is introduced slightly off-axis in such an arrangement, it must complete many rotations before coming back to its starting point. Such off-axis delay lines have been used in laser gravitational wave detectors. A similar resonator has been used by another group. In the authors' configuration, the internal reflections minimize reflection and scattering losses. The spherical surfaces can be figured extremely accurately. The system is achromatic, and thus multifrequency operation to eliminate cavity drifts is possible. A model analysis for this cavity is presented including estimates of the error due to Rayleigh scattering. Generalization of this configuration to include cavities with a greater number of faces and their advantages are discussed
Loop space representation of quantum general relativity and the group of loops
International Nuclear Information System (INIS)
Gambini, R.
1991-01-01
The action of the constraints of quantum general relativity on a general state in the loop representation is coded in terms of loop derivatives. These differential operators are related to the infinitesimal generators of the group of loops and generalize the area derivative first considered by Mandelstam. A new sector of solutions of the physical states space of nonperturbative quantum general relativity is found. (orig.)
Modeling of charged anisotropic compact stars in general relativity
Energy Technology Data Exchange (ETDEWEB)
Dayanandan, Baiju; Maurya, S.K.; T, Smitha T. [University of Nizwa, Department of Mathematical and Physical Sciences, College of Arts and Science, Nizwa (Oman)
2017-06-15
A charged compact star model has been determined for anisotropic fluid distribution. We have solved the Einstein-Maxwell field equations to construct the charged compact star model by using the radial pressure, the metric function e{sup λ} and the electric charge function. The generic charged anisotropic solution is verified by exploring different physical conditions like causality condition, mass-radius relation and stability of the solution (via the adiabatic index, TOV equations and the Herrera cracking concept). It is observed that the present charged anisotropic compact star model is compatible with the star PSR 1937+21. Moreover, we also presented the EOS ρ = f(p) for the present charged compact star model. (orig.)
Directory of Open Access Journals (Sweden)
Jackeline Cintra SOARES
2018-05-01
Full Text Available Abstract The aim of this study was to evaluate in sherbet formation the effects of sugar, milk, and jambolan pulp quantity on the overrun, color, physicochemical characteristics, microbiological characteristics, and acceptance of the experimental sherbets, in addition to evaluating the bioactive compounds of the selected product. Seven formulations were established through the Simplex method. The formulation with 20g 100g-1 sugar, 45g 100g-1 milk, and 35g 100g-1 jambolan pulp was selected (S5 because it was included among the most accepted sensorially (S4 and S5, and also presented higher overrun, chroma, SST/AT, and pH than S4, receiving the scores 8.0; 8.2, 6.4 and 7.1 and 6.1, respectively, for appearance, color, flavor, texture, and odor. The selected sherbet presented a high total phenolic compound content of 192mg gallic acid g-1, and a percentage of DPPH inhibition of 73%. It is concluded that it is possible to produce jambolan sherbet with desirable physical, chemical, microbiological, and sensory characteristics, which can increase the possibilities of applying the fruit as an ingredient in the edible ice cream industry.
Directory of Open Access Journals (Sweden)
Ahmad Reza Ghasemi
2016-07-01
Full Text Available Today, human capital is considered a key factor of achieving the competitive advantage in different industries. The present study, as an applied and descriptive research, aims at providing formulation and evaluation of human resource development of an Iranian Petrochemical Company (APC. The human resource experts and managers of APC together with university professors of human capital and familiar with local conditions of Khuzestan province, Iran, made up the statistical population of this research. In this connection, first the internal factors (including advantages and disadvantages were identified using human resource excellence indicators. Then, the opportunities and threats of human resource system were found via PESTEL approach. In the next step, the primary strategies were formulated using the strength, weakness, opportunities and threats (SWOT Matrix. The next phases of the study were included evaluation and ranking of human resource development strategies based on analytical network process (ANP multi-criteria decision making method and grey systems theory. According to results of the research, defensive strategies (WT are suggested as the best and most appropriate strategies in human resource area. In other words, the internal and external factors of APC are problematic. Accordingly, APC is expected to adopt WT strategy, minimize the weaknesses, and avoid threats. Subsequent to the above policy, the strategies of WO, ST, and SO are advised to employ.
Generality of a congruity effect in judgements of relative order.
Liu, Yang S; Chan, Michelle; Caplan, Jeremy B
2014-10-01
The judgement of relative order (JOR) procedure is used to investigate serial-order memory. Measuring response times, the wording of the instructions (whether the earlier or the later item was designated as the target) reversed the direction of search in subspan lists (Chan, Ross, Earle, & Caplan Psychonomic Bulletin & Review, 16(5), 945-951, 2009). If a similar congruity effect applied to above-span lists and, furthermore, with error rate as the measure, this could suggest how to model order memory across scales. Participants performed JORs on lists of nouns (Experiment 1: list lengths = 4, 6, 8, 10) or consonants (Experiment 2: list lengths = 4, 8). In addition to the usual distance, primacy, and recency effects, instructions interacted with serial position of the later probe in both experiments, not only in response time, but also in error rate, suggesting that availability, not just accessibility, is affected by instructions. The congruity effect challenges current memory models. We fitted Hacker's (Journal of Experimental Psychology: Human Learning and Memory, 6(6), 651-675, 1980) self-terminating search model to our data and found that a switch in search direction could explain the congruity effect for short lists, but not longer lists. This suggests that JORs may need to be understood via direct-access models, adapted to produce a congruity effect, or a mix of mechanisms.
77 FR 47922 - Publication of General Licenses Related to the Burma Sanctions Program
2012-08-10
... DEPARTMENT OF THE TREASURY Office of Foreign Assets Control Publication of General Licenses Related to the Burma Sanctions Program AGENCY: Office of Foreign Assets Control, Treasury. ACTION: Notice, publication of general licenses. [[Page 47923
Iz ''general relativity'' necessary for the Einstein gravitation theory gravitation theory
International Nuclear Information System (INIS)
Bondi, G.
1982-01-01
Main principles of relativity and gravitation theories are deeply analyzed. Problems of boundaries of applicability for these theories and possible ways of their change and generalization are discussed. It is shown that the notion of general relativity does not introduce any post-newton physics - it only deals with coordinate transformations. It is supposed that ''general relativity'' is a physically senseless phrase which can be considered only as a historical remainder of an interesting philosophic discourse. The paper reveals that there exists appropriate physical substantiation of the Einstein gravitation theory not including a physically senseless concept of general relativity and promoting its fundamental relations with the experiment
Schneid, Stefan C; Stärtzel, Peter M; Lettner, Patrick; Gieseler, Henning
2011-01-01
The recent US Food and Drug Administration (FDA) legislation has introduced the evaluation of the Design Space of critical process parameters in manufacturing processes. In freeze-drying, a "formulation" is expected to be robust when minor deviations of the product temperature do not negatively affect the final product quality attributes. To evaluate "formulation" robustness by investigating the effect of elevated product temperature on product quality using a bacterial vaccine solution. The vaccine solution was characterized by freeze-dry microscopy to determine the critical formulation temperature. A conservative cycle was developed using the SMART™ mode of a Lyostar II freeze dryer. Product temperature was elevated to imitate intermediate and aggressive cycle conditions. The final product was analyzed using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), Karl Fischer, and modulated differential scanning calorimetry (MDSC), and the life cell count (LCC) during accelerated stability testing. The cakes processed at intermediate and aggressive conditions displayed larger pores with microcollapse of walls and stronger loss in LCC than the conservatively processed product, especially during stability testing. For all process conditions, a loss of the majority of cells was observed during storage. For freeze-drying of life bacterial vaccine solutions, the product temperature profile during primary drying appeared to be inter-related to product quality attributes.
Rizzo, Joseph M; Shi, Shuai; Li, Yunsong; Semple, Andrew; Esposito, Jessica J; Yu, Shenjiang; Richardson, Daisy; Antochshuk, Valentyn; Shameem, Mohammed
2015-05-01
In this study, an automated high-throughput relative chemical stability (RCS) assay was developed in which various therapeutic proteins were assessed to determine stability based on the resistance to denaturation post introduction to a chaotrope titration. Detection mechanisms of both intrinsic fluorescence and near UV circular dichroism (near-UV CD) are demonstrated. Assay robustness was investigated by comparing multiple independent assays and achieving r(2) values >0.95 for curve overlays. The complete reversibility of the assay was demonstrated by intrinsic fluorescence, near-UV CD, and biologic potency. To highlight the method utility, we compared the RCS assay with differential scanning calorimetry and dynamic scanning fluorimetry methodologies. Utilizing C1/2 values obtained from the RCS assay, formulation rank-ordering of 12 different mAb formulations was performed. The prediction of long-term stability on protein aggregation is obtained by demonstrating a good correlation with an r(2) of 0.83 between RCS and empirical aggregation propensity data. RCS promises to be an extremely useful tool to aid in candidate formulation development efforts based on the complete reversibility of the method to allow for multiple assessments without protein loss and the strong correlation between the C1/2 data obtained and accelerated stability under stressed conditions. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
Further Generalization of Golden Mean in Relation to Euler Divine Equation
Rakocevic, Miloje M.
2006-01-01
In the paper a new generalization of the Golden mean, as a further generalization in relation to Stakhov (1989) and to Spinadel (1999), is presented. Also it is first observed that the Euler divine equation represents a possible generalization of Golden mean. In this second version the Section 6 is added.
Radic-Sestic, Marina; Radovanovic, Vesna; Milanovic-Dobrota, Biljana; Slavkovic, Sanela; Langovic-Milicvic, Ana
2013-01-01
The general objective of this study was to establish the relation between general and special education teachers within teamwork and to define socio-demographic factors that affect teamwork. The sample encompassed 223 general and special education teacher of both genders, age 25 to 60, who are employed in regular elementary schools in Serbia. The…
4-dimensional General Relativity from the instrinsic spatial geometry of SO(3) Yang-Mills theory
International Nuclear Information System (INIS)
Ita, Eyo Eyo
2011-01-01
In this paper we derive 4-dimensional General Relativity from three dimensions, using the intrinsic spatial geometry inherent in Yang-Mills theory which has been exposed by previous authors as well as some properties of the Ashtekar variables. We provide various interesting relations, including the fact that General Relativity can be written as a Yang-Mills theory where the antiself-dual Weyl curvature replaces the Yang-Mills coupling constant. We have generalized the results of some previous authors, covering Einstein's spaces, to include more general spacetime geometries.
Parametrizations in scalar-tensor theories of gravity and the limit of general relativity
International Nuclear Information System (INIS)
Järv, L; Kuusk, P; Saal, M; Vilson, O
2014-01-01
We consider a general scalar-tensor theory of gravity and review briefly different forms it can be presented (different conformal frames and scalar field parametrizations). We investigate the conditions under which its field equations and the parametrized post-Newtonian parameters coincide with those of general relativity. We demonstrate that these so-called limits of general relativity are independent of the parametrization of the scalar field, although the transformation between scalar fields may be singular at the corresponding value of the scalar field. In particular, the limit of general relativity can equivalently be determined and investigated in the commonly used Jordan and Einstein frames.
Tilted Bianchi type I dust fluid cosmological model in general relativity
Indian Academy of Sciences (India)
Tilted Bianchi type I dust ﬂuid cosmological model in general relativity ... In this paper, we have investigated a tilted Bianchi type I cosmological model ﬁlled with dust of perfect ﬂuid in general relativity. ... Pramana – Journal of Physics | News ...
29 CFR 541.201 - Directly related to management or general business operations.
2010-07-01
... management or general business operations. (a) To qualify for the administrative exemption, an employee's... operations of the employer or the employer's customers. The phrase “directly related to the management or... 29 Labor 3 2010-07-01 2010-07-01 false Directly related to management or general business...
General relativity the most beautiful of theories : applications and trends after 100 years
2015-01-01
Generalising Newton's law of gravitation, general relativity is one of the pillars of modern physics. On the occasion of general relativity's centennial, leading scientists in the different branches of gravitational research review the history and recent advances in the main fields of applications of the theory, which was referred to by Lev Landau as “the most beautiful of the existing physical theories”.
ACADEMIC TRAINING LECTURE SERIES: Introduction to General Relativity and Black Holes
2003-01-01
10, 11, 12, 13, 14 February ACADEMIC TRAINING LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Introduction to General Relativity and Black Holes by T.DAMOUR, IHES, Bures-sur-Yvette, F - Physical motivation behind Einstein's theory. - Mathematical formalism of General Relativity. - Experimental confirmations of Einstein's theory. - Introduction to Black Holes physics.
Estimation of unknown nuclear masses by means of the generalized mass relations. Pt. 3
International Nuclear Information System (INIS)
Popa, S.M.
1980-01-01
A survey of the estimations of the unknown nuclear masses by means of the generalized mass relations is presented. One discusses the new hypotheses supplementing the original general Garvey-Kelson scheme, reviewing the generalized mass relations and formulae, according to the present status of this new formalism. A critical discussions is given of the reliability of these new Garvey-Kelson type extrapolation procedures. (author)
Generalized Yosida Approximations Based on Relatively A-Maximal m-Relaxed Monotonicity Frameworks
Directory of Open Access Journals (Sweden)
Heng-you Lan
2013-01-01
Full Text Available We introduce and study a new notion of relatively A-maximal m-relaxed monotonicity framework and discuss some properties of a new class of generalized relatively resolvent operator associated with the relatively A-maximal m-relaxed monotone operator and the new generalized Yosida approximations based on relatively A-maximal m-relaxed monotonicity framework. Furthermore, we give some remarks to show that the theory of the new generalized relatively resolvent operator and Yosida approximations associated with relatively A-maximal m-relaxed monotone operators generalizes most of the existing notions on (relatively maximal monotone mappings in Hilbert as well as Banach space and can be applied to study variational inclusion problems and first-order evolution equations as well as evolution inclusions.
About the origins of the general theory of relativity: Einstein's search for the truth
Trainer, M.
2005-01-01
On the 20th June 1933 Professor Einstein addressed a large and enthusiastic audience in the Victorian Gothic Bute Hall of the University of Glasgow. Einstein spoke 'About the Origins of the General Theory of Relativity'. In 1905 Einstein had changed the face of physics forever with the publication of his radical new ideas on special relativity. His general theory of relativity was introduced to the world in 1915. However in 1933, Einstein faced another challenge—survival in a world of change....
International Nuclear Information System (INIS)
Philipp, M; Vergnat, C; Mueller, U; Sanctuary, R; Baller, J; Krueger, J K; Possart, W; Alnot, P
2009-01-01
The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies-including the generalized Cauchy relation-to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol-gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.
Philipp, M; Vergnat, C; Müller, U; Sanctuary, R; Baller, J; Possart, W; Alnot, P; Krüger, J K
2009-01-21
The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies-including the generalized Cauchy relation-to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol-gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.
Energy Technology Data Exchange (ETDEWEB)
Philipp, M; Vergnat, C; Mueller, U; Sanctuary, R; Baller, J; Krueger, J K [Laboratoire de Physique des Materiaux, Universite du Luxembourg, 162A, avenue de la Faiencerie, L-1511 Luxembourg (Luxembourg); Possart, W [Fachbereich Werkstoffwissenschaften, Universitaet des Saarlandes, D-66123 Saarbruecken (Germany); Alnot, P [LPMI, Universite Nancy (France)], E-mail: martine.philipp@uni.lu
2009-01-21
The non-equilibrium process of polymerization of reactive polymers can be accompanied by transition phenomena like gelation or the chemical glass transition. The sensitivity of the mechanical properties at hypersonic frequencies-including the generalized Cauchy relation-to these transition phenomena is studied for three different polyurethanes using Brillouin spectroscopy. As for epoxies, the generalized Cauchy relation surprisingly holds true for the non-equilibrium polymerization process and for the temperature dependence of polyurethanes. Neither the sol-gel transition nor the chemical and thermal glass transitions are visible in the representation of the generalized Cauchy relation. Taking into account the new results and combining them with general considerations about the elastic properties of the isotropic state, an improved physical foundation of the generalized Cauchy relation is proposed.
Smalley, L. L.
1983-01-01
The proper framework for testing Rastall's theory and its generalizations is in the case of non-negligible (i.e. discernible) gravitational effects such as gravity gradients. These theories have conserved integral four-momentum and angular momentum. The Nordtvedt effect then provides limits on the parameters which arise as the result of the non-zero divergence of the energy-momentum tensor.
Directory of Open Access Journals (Sweden)
Scichilone N
2014-11-01
Full Text Available Nicola Scichilone,1 Alida Benfante,1 Luca Morandi,2 Federico Bellini,2 Alberto Papi21Biomedical Department of Internal and Specialist Medicine, Section of Pulmonology, University of Palermo, Italy; 2Respiratory Medicine, Department of Medical Sciences, University of Ferrara, Ferrara, ItalyAbstract: Asthma and chronic obstructive pulmonary disease (COPD are among the most common chronic diseases worldwide, characterized by a condition of variable degree of airway obstruction and chronic airway inflammation. A large body of evidence has demonstrated the importance of small airways as a pharmacological target in these clinical conditions. Despite a deeper understanding of the pathophysiological mechanisms, the epidemiological observations show that a significant proportion of asthmatic and COPD patients have a suboptimal (or lack of control of their diseases. Different factors could influence the effectiveness of inhaled treatment in chronic respiratory diseases: patient-related (eg, aging; disease-related (eg, comorbid conditions; and drug-related/formulation-related factors. The presence of multiple illnesses is common in the elderly patient as a result of two processes: the association between age and incidence of degenerative diseases; and the development over time of complications of the existing diseases. In addition, specific comorbidities may contribute to impair the ability to use inhalers, such as devices for efficient drug delivery in the respiratory system. The inability to reach and treat the peripheral airways may contribute to the lack of efficacy of inhaled treatments. The recent development of inhaled extrafine formulations allows a more uniform distribution of the inhaled treatment throughout the respiratory tree to include the peripheral airways. The beclomethasone/formoterol extrafine formulation is available for the treatment of asthma and COPD. Different biomarkers of peripheral airways are improved by beclomethasone
Van Regenmortel, Tina; Janssen, Colin R; De Schamphelaere, Karel A C
2015-07-01
Although it is increasingly recognized that biotic ligand models (BLMs) are valuable in the risk assessment of metals in aquatic systems, the use of 2 differently structured and parameterized BLMs (1 in the United States and another in the European Union) to obtain bioavailability-based chronic water quality criteria for copper is worthy of further investigation. In the present study, the authors evaluated the predictive capacity of these 2 BLMs for a large dataset of chronic copper toxicity data with 2 Daphnia magna clones, termed K6 and ARO. One BLM performed best with clone K6 data, whereas the other performed best with clone ARO data. In addition, there was an important difference between the 2 BLMs in how they predicted the bioavailability of copper as a function of pH. These modeling results suggested that the effect of pH on chronic copper toxicity is different between the 2 clones considered, which was confirmed with additional chronic toxicity experiments. Finally, because fundamental differences in model structure between the 2 BLMs made it impossible to create an average BLM, a generalized bioavailability model (gBAM) was developed. Of the 3 gBAMs developed, the authors recommend the use of model gBAM-C(uni), which combines a log-linear relation between the 21-d median effective concentration (expressed as free Cu(2+) ion activity) and pH, with more conventional BLM-type competition constants for sodium, calcium, and magnesium. This model can be considered a first step in further improving the accuracy of chronic toxicity predictions of copper as a function of water chemistry (for a variety of Daphnia magna clones), even beyond the robustness of the current BLMs used in regulatory applications. © 2015 SETAC.
DEFF Research Database (Denmark)
Lundstrøm, Sanne Lykke; Edwards, Kasper; Reventlow, Susanne
2014-01-01
In this paper we investigate the association between relational coordination among the practice team in general practice and number of consultations performed in a general practice per staff, i.e. a proxy of productivity. We measured relational coordination using the Relational Coordination Survey...... and combined the results with register data. We found that relational coordination was statistically significant associated with number of consultation per staff per year. We later divided consultations in to three types: Face-to-face, Email and phone consultations. We found a statistically significant...... associating between relational coordination and with number of face-to-face consultation per staff per year....
Muschalla, Beate; Glatz, Johannes; Linden, Michael
2014-01-01
Absence of an adequate reason for anxiety is a criterion for pathological anxiety. However, the presence of danger or fear-provoking stimuli may even be a risk factor for anxiety and does not exclude that there is additionally pathological anxiety too. The question is, to what degree can heart-related anxiety be explained by the severity of illness or trait anxiety? Two hundred and nine patients (37.8% women) from a cardiology inpatient unit completed the Heart-Anxiety-Questionnaire, Progression-Anxiety-Questionnaire, Job-Anxiety-Scale and the State-Trait-Anxiety-Inventory. The severity of cardiac illness was rated by the treating cardiologists using the Multidimensional Severity of Morbidity Rating. Time absent from work due to sickness was assessed as an indicator for illness-related impairment. Heart anxiety was significantly related to progression anxiety and, to a lesser extent, trait anxiety and indicators of subjective symptoms of somatic illness. No association was found with medical ratings for prognosis, multimorbidity, or reduction in life expectancy. Heart-related anxiety is a symptom of an anxiety disorder. Although partially dependent on subjective suffering, it cannot be explained by the severity of medical illness. Treatment of health-related anxieties should focus on how to cope with subjective symptoms of illness.