Browsing Physics & Astronomy by Subject "Black holes"

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  • Das, Saurya; Dasgupta, Arundhati (SISSAPennsylvania State UniversityInstitute of Mathematical Sciences (India), 1999)
    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 ...
  • Das, Saurya (Arts and ScienceDepartment of PhysicsUniversity of Lethbridgehttps://www.ias.ac.in/article/fulltext/pram/063/04/0797-0815, 2015-12-16)
    We review some recent advances in black hole thermodynamics, including statistical mechanical origins of black hole entropy and its leading order corrections, from the viewpoints of various quantum gravity theories. We ...
  • Sur, Sourav; Das, Saurya; SenGupta, Soumitra (Arts and ScienceDepartment of PhysicsInstitute of PhysicsUniversity of LethbridgeIndian Association for the Cultivation of Science, 2015-12-16)
    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 ...
  • Das, Saurya; Mann, Robert B. (SISSAPennsylvania State UniversityUniversity of Waterloohttp://iopscience.iop.org/1126-6708/2000/08/033, 2000)
    We compute the conserved charges for Kerr anti-de Sitter spacetimes in various dimensions using the conformal and the counterterm prescriptions. We show that the conserved charge corresponding to the global timelike ...
  • Das, Saurya; Majumdar, Parthasarathi (American Physical SocietyInstitute of Mathematical Sciences (India)https://doi.org/10.1103/PhysRevD.55.2090, 1997)
    Approximating light charged pointlike particles in terms of ~nonextremal! dilatonic black holes is shown to lead to certain pathologies in Planckian scattering in the eikonal approximation, which are traced to the presence ...
  • Braunstein, Samuel L.; Das, Saurya; Shankaranarayanan, S. (Arts and ScienceDepartment of PhysicsUniversity of YorkUniversity of LethbridgeIndian Institute of Science Education and Research, 2015-12-15)
    It has long been conjectured that the entropy of quantum fields across boundaries scales as the boundary area. This conjecture has not been easy to test in spacetime dimensions greater than four because of divergences ...
  • Vagenas, Elias C.; Das, Saurya (Arts and ScienceDepartment of PhysicsUniversity of AthensUniversity of Lethbridge, 2016-01-06)
    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 ...
  • Das, Saurya; Robinson, Sean P.; Vagenas, Elias C. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeMassachusetts Institute of TechnologyUniversity of Athens, 2016-01-07)
    We explore the method of Robinson andWilczek for deriving the Hawking temperature of a black hole. In this method, the Hawking radiation restores general covariance in an effective theory of near-horizon physics which ...
  • Das, Saurya; Dasgupta, Arundhati; Sarkar, Tapobrata (American Physical SocietyArts and ScienceInstitute of Mathematical Sciences (India)https://doi.org/10.1103/PhysRevD.55.7693, 1997)
    We study the emission of scalar particles from a class of near-extremal five-dimensional black holes and the corresponding D-brane configuration at high energies. We show that the distribution functions and the black hole ...
  • Das, Saurya; Shankaranarayanan, S. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeThe Abdus Salam International Centre for Theoretical Physicshttps://doi.org/10.1088/0264-9381/22/3/L01, 2015-12-23)
    We compute the high frequency quasi-normal modes (QNM) for scalar perturbations of spherically symmetric single horizon black-holes in (D+2)-space-time dimensions with generic curvature singularities and having metrics ...
  • Ghosh, Archisman; Shankaranarayanan, S.; Das, Saurya (Arts and ScienceDepartment of PhysicsIndian Institute of Technology KanpurThe Abdus Salam International Centre for Theoretical PhysicsUniversity of Lethbridgehttps://doi.org/10.1088/0264-9381/23/6/003, 2016-01-05)
    The possibility that the asymptotic quasi-normal mode (QNM) frequencies can be used to obtain the Bekenstein-Hawking entropy for the Schwarzschild black hole — commonly referred to as Hod’s conjecture — has received ...
  • Cavagalià, Marco; Das, Saurya (Arts and ScienceDepartment of PhysicsUniversity of MississippiUniversity of Lethbridgehttps://doi.org/10.1088/0264-9381/21/19/001, 2015-12-23)
    We show that the Hawking temperature and the entropy of black holes are subject to corrections from two sources: the generalized uncertainty principle and thermal fluctuations. Both effects increase the temperature and ...
  • Bhaduri, Rajat K.; Tran, Muoi N.; Das, Saurya (Arts and ScienceDepartment of PhysicsMcMaster UniversityUniversity of Lethbridgehttps://doi.org/10.1103/PhysRevD.69.104018, 2016-01-25)
    It has been suggested recently that the microcanonical entropy of a system may be accurately reproduced by including a logarithmic correction to the canonical entropy. In this paper we test this claim both analytically ...
  • Das, Saurya; Dasgupta, Arundhati; Ramadevi, P.; Sarkar, Tapobrata (Elsevier BV North HollandInstitute of Mathematical Sciences (India)International Centre for Theoretical PhysicsTata Institute of Fundamental Research, 1988)
    We consider the gravitational scattering of point particles in four dimensions, at Planckian centre of mass energy and low momentum transfer, or the eikonal approximation. The scattering amplitude can be exactly computed ...
  • Das, Saurya; Ramadevi, P.; Yajnik, U. A.; Sule, A. (ElsevierUniversity of New BrunswickIndian Institute of Technology Bombay, 2003)
    It has been argued by several authors, using different formalisms, that the quantum mechanical spectrum of black hole horizon area is discrete and uniformly spaced. Recently it was shown that two such approaches, namely ...
  • Barvinsky, Andrei; Das, Saurya; Kunstatter, Gabor (ElsevierLebedev Physics Institute and Lebedev Research Center in PhysicsUniversity of Winnipeg, 2001)
    We quantize the spherically symmetric sector of generic charged black holes. Thermal properties are incorporated by imposing periodicity in Euclidean time, with period equal to the inverse Hawking temperature of the black ...
  • Das, Saurya; Majumdar, Parthasarathi (Elsevier BV North HollandInstitute of Mathematical Sciences (India)International Centre for Theoretical Physics, 1995)
    We consider possible mixing of electromagnetic and gravitational shock waves, in the Planckian energy scattering of point particles in Minkowski space, By boosting a Reissner-Nordstriim black hole solution to the velocity ...
  • Das, Saurya; Mukhopadhyay, Himan; Ramadevi, P. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeIndian Institute of Technologyhttps://doi.org/10.1088/0264-9381/22/2/015, 2015-12-16)
    The reduced phase space formalism for quantising black holes has recently been extended to find the area and angular momentum spectra of four dimensional Kerr black holes. We extend this further to rotating black holes ...
  • Das, Saurya; Shankaranarayanan, S.; Sur, Sourav (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeMax-Planck-Institut für Gravitationphysikhttps://doi.org/10.1139/p07-183, 2015-12-15)
    Considering the entanglement between quantum field degrees of freedom inside and outside the horizon as a plausible source of black hole entropy, we address the question: where are the degrees of freedom that give rise ...