22845460
Birkhoff's theorem for electromagnetic fields in a new scalar-tensor theory.
A result having formal similarity to Birkhoff's theorem in general relativity is proved in the presence of electromagnetic fields in a new scalar-tensor theory of gravitation proposed by Schmidt et al. for the special case when the scalar field is massless and independent of time.
122267670
Some static solutions in the general scalar‐tensor theory
Exact solutions are found for the static gravitational fields for a matter‐free space in the general scalar‐tensor theory of Nordtvedt–Barker–Schwinger. The singular behavior of some of the invariants has also been discussed for the solutions in Barker and Schwinger theories.
123030808
Field of a charged particle in general scalar-tensor theory
The field equations in the general scalar-tensor theory of gravitation proposed by Bergmann, Wagoner, and Nordtvedt are studied for a charged static and spherically symmetric vacuum field. Closed-form exact solutions of the field equations are presented for the scalar-tensor theories in the form due to Barker and Schwinger. The solutions may be considered as describing the field of a charged mass point surrounded by a scalar-tensor field.
127634712
Axisymmetric stationary gravitational and Maxwell fields in the general scalar tensor theory
It is shown that the axisymmetric stationary gravitational and Maxwell fields in the general scalar tensor theory can be obtained from the axisymmetric stationary Einstein — Maxwell fields. The scalar-tensor analogue of the Kerr-Newman solution has been obtained by this method.
121368055
GENERAL CLASS OF SCALAR-TENSOR THEORIES: A REVIEW
The general class of scalar-tensor theories is discussed in which, in contrast to Brans-Dicke theory, the coupling parameter ω is not a constant but a function of the scalar field ϕ. Some other generalizations of the Brans-Dicke theory have also been discussed in brief. The physical aspects of these theories have been dealt. The cosmological models in scalar-tensor theories have been discussed in detail. Finally some open problems in these theories have been pointed out.
34781515
Magnetic wormholes and vertex operators.
We consider wormhole solutions in 2+1 Euclidean dimensions. A duality transformation is introduced to derive a new action from the magnetic wormhole action of Gupta, Hughes, Preskill, and Wise. The classical solution is presented. The vertex operators corresponding to the wormhole are derived. Conformally coupled scalars and spinors are considered in the wormhole background and the vertex operators are computed.
38815785
Baryon-number fluctuations in a quark-hadron phase transition.
Isothermal baryon-number fluctuations arising from a first-order quark-hadron phase transition in the early Universe are obtained by including the quark-gluon interactions up to the order [ital g][sub [ital s]][sup 3] in the perturbative QCD coupling constant in the quark-gluon plasma (QGP) phase and the finite-size volume corrections for the hadrons in the hadron-resonance gas (HRG) and their effects on the primordial nucleosynthesis (PNS) are analyzed. The ratio of the baryon-number densities in the QGP and HRG phases at the critical temperature [ital T][sub [ital c]] is larger than one in the range 150 MeV[lt][ital T][sub [ital c]][lt]260 MeV. However, it is far larger than one even when [ital T][sub [ital c]] is outside this range, thus affecting primordial nucleosynthesis significantly.
35249306
Quantum violation of stochastic noncontextual hidden-variable theories.
We formulate stochastic noncontextual hidden-variable theories. In such theories the hidden state λ specifies not definite values, but expectation values A − (λ), ... of observables A, ... and noncontextuality means that A − (λ) is independent of which other commuting observables commuting with A are measured together with A. We show via Bell inequalities that such theories conflict with quantum theory and propose a two-photon experimental test. We also show that for a single particle of spin (2 n −1)/2, quantum violation of classical noncontextuality grows exponentially with n.
41488413
Temperature and baryon-chemical-potential-dependent bag pressure for a deconfining phase transition.
We explore the consequences of a bag model developed by Leonidov {ital et} {ital al}. for the deconfining phase transition in which the bag pressure is made to depend on the temperature and baryon chemical potential in order to ensure the entropy and baryon number conservation at the phase boundary together with the Gibbs construction for an equilibrium phase transition. We show that the bag pressure thus obtained yields an anomalous increasing behavior with the increasing baryon chemical potential at a fixed temperature which defies a physical interpretation. We demonstrate that the inclusion of the perturbative interactions in the QGP phase removes this difficulty. Further consequences of the modified bag pressure are discussed. {copyright} {ital 1996 The American Physical Society.}
35837302
Baryon-number density in hadronic gas models and baryon asymmetry in the early Universe.
We have recently shown that the inclusion of finite-size volume corrections for the hadrons in the hadronic gas phase drastically alters the conclusions regarding isothermal baryon-number fluctuations arising from a first-order quark-hadron phase transition in the early Universe. In this paper we compare in detail the predictions of various existing thermodynamically consistent hadron gas (HG) models for the baryon density in the HG phase and its dependence on the temperature in order to draw a firm conclusion regarding the results obtained in the earlier paper. \textcopyright{} 1996 The American Physical Society.