• Alok Kumar

      Articles written in Pramana – Journal of Physics

    • D-branes inpp-wave background

      Alok Kumar Rashmi R Nayak Sanjay

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      We show the existence of classical solutions ofD-branes as well as a system ofD3-branes oriented at an arbitrary angle with respect to each other, in a six-dimensionalpp-wave background obtained fromAdS3 × S3 ×R4, withR — R andNS — NS 3-from flux. The world volume coordinate of D5-brane lies along the six-dimensional pp-wave directions, whereas thepp-wave direction is transverse to the system of D3-branes. We also present moreD-brane bound state solutions by applyingT-duality symmetries. The system ofD3-branes oriented at an arbitrary angle is shown to preserve 1/16 supersymmetries. Finally a brief discussion of the open string construction is presented for both the cases.

    • Intersectingp — p′ branes inpp-wave background

      Anindya Biswas Alok Kumar Kamal L Panigrahi

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      Several supergravity solutions corresponding to bothDp, as well asDp—Dp′ systems, inNS-NS andR-R pp-wave background originating fromAdS3 xS3 xR4 are presented. The supersymmetry properties of these solutions are analysed along with a brief outline of the world sheet construction for thep — p′ branes.

    • Understanding the spreading of a Gaussian wave packet using the Bohmian machinery

      Alok Kumar Pan

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      A freely propagating Gaussian wave packet naturally spreads with time. Exploiting the machinery of the Bohmian model of quantum mechanics, the way the wave packet spreads is re-examined.

    • Construction of topological conformal field theories

      Alok Kumar

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      In this lecture I review the construction of two dimensional Topologiccal Conformal Field Theories fromN=2 superconformal theories. We show that a BRST structure emerges upon a twisting of theN=2 superconformal algebra. Moreover, the energy-momentum tensor of the twisted theory is BRST-exact and all the physical correlation functions are independeent of the two dimensional metric. We briefly mention several generalizations such as the construction of topological superconformal theories as well as the topological conformal theories on higher genus Riemann surfaces.

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