Dirac field in topologically massive gravity

We consider a Dirac field coupled minimally to the Mielke–Baekler model of gravity and investigate cosmological solutions in three dimensions. We arrive at a family of solutions which exists even in the limit of vanishing cosmological constant.     

Spin-3 topologically massive gravity

In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS₃ vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W₃ algebra and central charge cR=3l/G.     

Constrained analysis of topologically massive gravity

We quantize the Einstein gravity in the formalism of weak gravitational fields by using the constrained Hamiltonian method. Special emphasis is given to the 2+1 spacetime dimensional case where a (topological) Chern-Simons term is added to the Lagrangian.     

Logarithmic conformal field theory approach to topologically massive gravity

We study the topologically massive gravity at the chiral point (chiral gravity) by using the logarithmic conformal field theory. Two new tensor fields of ψnew${\psi }^{\mathrm{new}}$ and X   are introduced for a candidate of propagating physical field at the chiral point. However, we show that (ψnew,ψL${\psi }^{\mathrm{new}},{\psi }^L$) form a dipole ghost pair of unphysical fields and X is not a primary. This implies that there is no physically propagating degrees of freedom at the chiral point.     

Iterative abel inversion of optically thick,cylindrically symmetric radiation sources

An inversion algorithm for obtaining the radial emission and absorption coefficients of a cylindrically symmetric radiation source from transverse profiles of monochromatic radiance and absorptance is described and compared with the algorithm of Elder et al. It is shown that the present method converges to the correct solution, whereas that of Elder et al. does not.     

Anomalies and Hawking fluxes from the black holes of topologically massive gravity

The anomaly cancelation method proposed by Wilczek et al. is applied to the black holes of topologically massive gravity (TMG) and topologically massive gravito-electrodynamics (TMGE). Thus the Hawking temperature and fluxes of the ACL and ACGL black holes are found. The Hawking temperatures obtained agree with the surface gravity formula. Both black holes are rotating and this gives rise to appropriate terms in the effective U(1)$\mathrm{U}(1)$ gauge field of the reduced (1+1)$(1+1)$-dimensional theory. It is found that the terms in this U(1)$\mathrm{U}(1)$ gauge field correspond exactly to the correct angular velocities on the horizon of both black holes as well as the correct electrostatic potential of the ACGL black hole. So the results for the Hawking fluxes derived here from the anomaly cancelation method, are in complete agreement with the ones obtained from integrating the Planck distribution.     

Absorption cross section in the topologically massive gravity at the critical point

The absorption cross section for the warped AdS₃ black hole background shows that it is larger than the area even if the s-wave limit is considered. It raises some question whether the deviation from the areal cross section is due to the warped configuration of the geometry or the rotating coordinate system, where these two effects are mixed up in the warped AdS₃ black hole. So, we study the low-frequency scattering dynamics of propagating scalar fields under the warped AdS₃ background at the critical point which reduces to the BTZ black hole in the rotating frame without the warped factor, which shows that the deformation effect at the critical point does not appear.     

Stationary,spherically symmetric solutions of Jordan's unified theory of gravity and electromagnetism

All stationary, spherically symmetric solutions of Jordan's unified theory of gravity and electromagnetism are constructed. Conditions for the solutions are given to represent black holes with nonvanishing mass, electric and magnetic charge.     

Nonpropagation of massive mode on AdS<Subscript>2</Subscript> in topologically massive gravity

Making use of Achucarro–Ortiz (AO) type of dimensional reduction, we study the topologically massive gravity with a negative cosmological constant on AdS₂ spacetimes. For a constant dilaton, this two-dimensional model also admits three AdS₂ vacuum solutions, which are related to two AdS₃ and warped AdS₃ backgrounds with an identification upon uplifting three dimensions. We carry out the perturbation analysis around these backgrounds to find what is a physically propagating field. However, it turns out that there is no propagating massive mode on AdS₂ background, in contrast to the Kaluza–Klein (KK) type of dimensional reduction. We note that two dimensionally reduced actions are different and thus, the non-equivalence of their on-shell amplitudes is obtained.     

A study of cylindrically symmetric solutions in $$f(R, phi,X)$$ theory of gravity

The European Physical Journal C - Much theoretical effort and automatization are required to confront new physics models with experimental data for many types of particle reactions at future...     

Cosmological sector for localized mass and spin in 2+1 dimensional topologically massive gravity

The cosmological sector to the full non-linear topologically massive gravity (TMG) is obtained for localized sources of mass m and spin σ besides the asymptotically spinning conical flat sector previously obtained [A. Edery, M.B. Paranjape, gr-qc/9606029, to be published]. In a small region near but outside the sources, the metric resembles the spinning conical flat metric but we find that the mass m creates a negative deficit angle of 3m as opposed to m. Furthermore, it is not possible to recover the results of pure Einstein gravity in the limit μ→∞ unlike the flat sector.     

Lorentz violation in the linearized gravity

We study some physical consequences of the introduction of a Lorentz-violating modification term in the linearized gravity, which leads to modified dispersion relations for gravitational waves in the vacuum. We discuss two possible mechanisms for the induction of such a term in the Lagrangian. First, it is generated at the quantum level by a Lorentz-breaking coupling of the gravity field to a spinor field. Second, it appears as consequence of a particular modification of the Poisson algebra of the canonical variables, in the spirit of the so-called “noncommutative fields approach”.     

Magnetized cylindrically symmetric universe in general relativity

A magnetized cylindrically symmetric universe with two degrees of freedom in which the free gravitational field is Petrov type I degenerate, is obtained. The magnetic field is due to an electric current produced along the x-axis. The distribution consists of an electrically neutral perfect fluid with an infinite electrical conductivity. The behaviour of the model when magnetic field tends to zero and other physical aspects of the model are also discussed.     

String cosmology in inhomogeneous cylindrically symmetric spacetime

String-dust cosmology in an inhomogeneous cylindrically symmetric model is considered. Solutions are obtained only for geometric string with the separability assumption for metric coefficients.