Das, Saurya

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https://opus.uleth.ca/handle/10133/3587

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Browsing Das, Saurya by Subject "Black holes in string theory"

Now showing 1 - 3 of 3
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    Black hole emission rates and the AdS/CFT correspondence
    (SISSA, 1999) Das, Saurya; Dasgupta, Arundhati
    We study the emission rates of scalar, spinor and vector particles from a 5 dimensional black hole for arbitrary partial waves. The solution is lifted to 6 dimensions, and the near horizon BTZ S3 geometry of the black hole solution is probed to determine the greybody factors. We show that the exact decay rates can be reproduced from a (1 + 1)-dimensional conformal eld theory which lies on the boundary of the near horizon geometry. The AdS/CFT correspondence is used to determine the dimension of the CFT operators corresponding to the bulk elds. These operators couple to plane waves incident on the CFT from in nity to produce emission in the bulk.
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    Charged black holes in generalized dilaton-axion gravity
    (2015-12-16) Sur, Sourav; Das, Saurya; SenGupta, Soumitra
    We study generic Einstein-Maxwell-Kalb-Ramond-dilaton actions, and derive conditions under which they give rise to static, spherically symmetric black hole solutions. We obtain new asymptotically flat and non-flat black hole solutions which are in general electrically and magnetically charged. They have positive definite and finite quasi-local masses. Existing non-rotating black hole solutions (including those appearing in low energy string theory) are recovered in special limits.
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    Gravitational anomalies, Hawking radiation, and spherically symmetric black holes
    (2016-01-06) Vagenas, Elias C.; Das, Saurya
    Motivated by the recent work of Robinson and Wilczek, we evaluate the gravitational anomaly of a chiral scalar field in a Vaidya spacetime of arbitrary mass function, and thus the outgoing flux from the time-dependent horizon in that spacetime. We show that this flux differs from that of a perfect blackbody at a fixed temperature. When this flux is taken into account, general covariance in that spacetime is restored. We also generalize their results to the most general static, and spherically symmetric spacetime.