• K S Virbhadra

      Articles written in Pramana – Journal of Physics

    • Spin precession of a charged particle in a uniform magnetic field on a static space-time

      K S Virbhadra A R Prasanna

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      We investigate the ratio of spin precession frequency to orbital frequency for a spinning charged particle confined to circular orbit in the equatorial plane of a compact object, with a uniform magnetic field, as described by the Wald and the Ernst potentials. In order to see the difference in behaviours for particles with differentg values we consider the cases of electron and proton separately.

    • Energy and momentum in Vaidya spacetime

      K S Virbhadra

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      The components of the energy-momentum pseudotensors of Einstein, Tolman, Landau and Lifshitz, and Møller are evaluated for the Vaidya radiating spacetime. These pseudotensors are found to be traceless for this spacetime. The pseudotensors of Einstein and Tolman give exactly same result for all their components. Unlike in the case of the Kerr-Newman field, the pseudotensor of Møller gives the same energy as given by that of the Einstein, Tolman or Landau and Lifshitz.

    • Gravitational field of a tachyon in a de Sitter universe

      K S Virbhadra

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      An exact solution of Einstein’s equations is interpreted as describing the gravitational field of a tachyon in a de Sitter universe. Switching off the cosmological constant yields the gravitational field of a tachyon in flat spacetime background.

    • Exact solutions of Einstein and Einstein-scalar equations in 2 + 1 dimensions

      K S Virbhadra

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      A nonstatic and circularly symmetric exact solution of the Einstein equations (with a cosmological constant Λ and null fluid) in 2 + 1 dimensions is given. This is a nonstatic generalization of the uncharged spinless BTZ metric. For Λ = 0, the spacetime is though not flat, the Kretschmann invariant vanishes. The energy, momentum, and power output for this metric are obtained. Further a static and circularly symmetric exact solution of the Einsteinmassless scalar equations is given, which has a curvature singularity atr = 0 and the scalar field diverges atr = 0 as well as at infinity.

    • Gravitational and electromagnetic fields of a charged tachyon

      K S Virbhadra

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      An axially symmetric exact solution of the Einstein-Maxwell equations is obtained and is interpreted to give the gravitational and electromagnetic fields of a charged tachyon. Switching off the charge parameter yields the solution for the uncharged tachyon which was earlier obtained by Vaidya. The null surfaces for the charged tachyon are discussed.

    • A radiating dyon solution

      A Chamorro K S Virbhadra

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      We give a non-static exact solution of the Einstein-Maxwell equations (with null fluid), which is a non-static magnetic charge generalization to the Bonnor-Vaidya solution and describes the gravitational and electromagnetic fields of a non-rotating massive radiating dyon. In addition, using the energy-momentum pseudotensors of Einstein and Landau and Lifshitz we obtain the energy, momentum, and power output of the radiating dyon and find that both prescriptions give the same result.

    • Energy and momentum of cylindrical gravitational waves-II

      K S Virbhadra

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      Recently Rosen and the present author obtained the energy and momentum densities of cylindrical gravitational waves in Einstein’s prescription and found them to be finite and reasonable. In the present paper we calculate the same in the prescriptions of Tolman as well as Landau and Lifshitz and discuss the results.

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