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Title: Strong gravitational lensing—a probe for extra dimensions and Kalb-Ramond field

Abstract

Strong field gravitational lensing in the context of both higher spacetime dimensions and in presence of Kalb-Ramond field have been studied. After developing proper analytical tools to analyze the problem we consider gravitational lensing in three distinct black hole spacetimes—(a) four dimensional black hole in presence of Kalb-Ramond field, (b) brane world black holes with Kalb-Ramond field and finally (c) black hole solution in f ( T ) gravity. In all the three situations we have depicted the behavior of three observables: the asymptotic position approached by the relativistic images, the angular separation and magnitude difference between the outermost images with others packed inner ones, both numerically and analytically. Difference between these scenarios have also been discussed along with possible observational signatures.

Authors:
;  [1]
  1. Department of Theoretical Physics, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C. Mullick Road, Kolkata 700032 (India)
Publication Date:
OSTI Identifier:
22676083
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2017; Journal Issue: 07; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMPTOTIC SOLUTIONS; BLACK HOLES; BRANES; FOUR-DIMENSIONAL CALCULATIONS; GLOBAL ASPECTS; GRAVITATIONAL FIELDS; GRAVITATIONAL LENSES; RELATIVISTIC RANGE; SPACE-TIME

Citation Formats

Chakraborty, Sumanta, and SenGupta, Soumitra, E-mail: sumantac.physics@gmail.com, E-mail: tpssg@iacs.res.in. Strong gravitational lensing—a probe for extra dimensions and Kalb-Ramond field. United States: N. p., 2017. Web. doi:10.1088/1475-7516/2017/07/045.
Chakraborty, Sumanta, & SenGupta, Soumitra, E-mail: sumantac.physics@gmail.com, E-mail: tpssg@iacs.res.in. Strong gravitational lensing—a probe for extra dimensions and Kalb-Ramond field. United States. doi:10.1088/1475-7516/2017/07/045.
Chakraborty, Sumanta, and SenGupta, Soumitra, E-mail: sumantac.physics@gmail.com, E-mail: tpssg@iacs.res.in. Sat . "Strong gravitational lensing—a probe for extra dimensions and Kalb-Ramond field". United States. doi:10.1088/1475-7516/2017/07/045.
@article{osti_22676083,
title = {Strong gravitational lensing—a probe for extra dimensions and Kalb-Ramond field},
author = {Chakraborty, Sumanta and SenGupta, Soumitra, E-mail: sumantac.physics@gmail.com, E-mail: tpssg@iacs.res.in},
abstractNote = {Strong field gravitational lensing in the context of both higher spacetime dimensions and in presence of Kalb-Ramond field have been studied. After developing proper analytical tools to analyze the problem we consider gravitational lensing in three distinct black hole spacetimes—(a) four dimensional black hole in presence of Kalb-Ramond field, (b) brane world black holes with Kalb-Ramond field and finally (c) black hole solution in f ( T ) gravity. In all the three situations we have depicted the behavior of three observables: the asymptotic position approached by the relativistic images, the angular separation and magnitude difference between the outermost images with others packed inner ones, both numerically and analytically. Difference between these scenarios have also been discussed along with possible observational signatures.},
doi = {10.1088/1475-7516/2017/07/045},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 07,
volume = 2017,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}
  • Kalb-Ramond gauge field theory, coupled to manifestly gauge-invariant and reparametrization-invariant second-quantized string fields, is studied. String condensation into the vacuum is shown to develop masses to the Kalb-Ramond gauge field which we call the string Higgs mechanism. In case the Kalb-Ramond field couples to the open strings which have a massless vector field in the spectrum, our field theory also exhibits the well-known Stueckelberg mechanism. To strengthen our conclusion, we construct a lattice version of the above string field theory and demonstrate that the mean-field approximation indicates the existence of the Higgs phase.
  • We have considered the most general gauge invariant five-dimensional action of a second rank antisymmetric Kalb-Ramond tensor gauge theory, including a topological term of the form {epsilon}{sup ABLMN}B{sub AB}H{sub LMN} in a Randall-Sundrum scenario. Such a tensor field B{sub AB} (whose rank-3 field strength tensor is H{sub LMN}), which appears in the massless sector of a heterotic string theory, is assumed to coexist with the gravity in the bulk. The third rank field strength corresponding to the Kalb-Ramond field has a well-known geometric interpretation as the space-time torsion. The only nontrivial classical solutions corresponding to the effective four-dimensional action aremore » found to be self-dual or anti-self-dual Kalb-Ramond fields. This ensures that the four-dimensional effective action on the brane is parity-conserving. The massive modes for both cases, lying in the TeV range, are related to the fundamental parameters of the theory. These modes can be within the kinematic reach of forthcoming TeV-scale experiments. However, the couplings of the massless as well as massive Kalb-Ramond modes with matter on the visible brane are found to be suppressed vis-a-vis that of the graviton by the warp factor, whence the conclusion is that both the massless and the massive torsion modes appear much weaker than curvature to an observer on the visible brane.« less
  • Electromagnetic and (linearized) gravitational interactions of the Kalb-Ramond (KR) field, derived from an underlying ten-dimensional heterotic string in the zero slope limit, are studied in a five-dimensional background Randall-Sundrum I spacetime with standard model fields confined to the visible brane having negative tension. The warp factor responsible for generating the gauge hierarchy in the Higgs sector is seen to appear inverted in the KR field couplings, when reduced to four dimensions. This leads to dramatically enhanced rotation, far beyond observational bounds, of the polarization plane of electromagnetic and gravitational waves, when scattered by a homogeneous KR background. Possible reasons formore » the conflict between theory and observation are discussed.« less
  • Effective gravitational field equations on a brane have been derived, when the bulk spacetime is endowed with the second rank antisymmetric Kalb–Ramond field. Since both the graviton and the Kalb–Ramond field are closed string excitations, they can propagate in the bulk. After deriving the effective gravitational field equations on the brane, we solve them for a static spherically symmetric solution. It turns out that the solution so obtained represents a black hole or naked singularity depending on the parameter space of the model. The stability of this model is also discussed. Cosmological solutions to the gravitational field equations have beenmore » obtained, where the Kalb–Ramond field is found to behave as normal pressure free matter. For certain specific choices of the parameters in the cosmological solution, the solution exhibits a transition in the behaviour of the scale factor and hence a transition in the expansion history of the universe. The possibility of accelerated expansion of the universe in this scenario is also discussed.« less
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