Physics & Astronomy: Recent submissions

  • 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; Kaul, Romesh K.; Majumdar, Parthasarathi (American Institute of PhysicsPennsylvania State UniversityThe Institute of Mathematical Sciences (India)https://doi.org/10.1103/PhysRevD.63.044019, 2001)
    A new entropy bound, tighter than the standard holographic bound due to Bekenstein, is derived for spacetimes with nonrotating isolated horizons from the quantum geometry approach, in which the horizon is described by ...
  • Das, Saurya; Ghosh, Amit; Mitra, P. (American Physical SocietyPennsylvania State UniversitySaha Institute of Nuclear Physics (Kolkata, India)https://doi.org/10.1103/PhysRevD.63.024023, 2000)
    The statistical entropy of a Schwarzschild black string in five dimensions is obtained by counting the black string states which form a representation of the near-horizon conformal symmetry with a central charge. ...
  • 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 ...
  • 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; Gegenberg, J.; Husain, V. (American Physical SocietyUniversity of WinnipegUniversity of New Brunswickhttps://doi.org/10.1103/PhysRevD.64.065027, 2001)
    We describe a class of asymptotically AdS scalar field spacetimes, and calculate the associated conserved charges for three, four and five spacetime dimensions using the conformal and counterterm prescriptions. The energy ...
  • Das, Saurya; Kobes, Randy; Kunstatter, Gabor (American Physical SocietyUniversity of WinnipegWinnipeg Institute for Theoretical Physicshttps://doi.org/10.1103/PhysRevA.65.062310, 2002)
    We show that by a suitable choice of a time-dependent Hamiltonian, Deutsch’s algorithm can be implemented by an adiabatic quantum computer. We extend our analysis to the Deutsch-Jozsa problem and estimate the required ...
  • 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 ...
  • Das, Saurya; Dey, Anindya; SenGupta, Soumitra (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeHarish-Chandra Research InstituteIndian Association for the Cultivation of Sciencehttps://doi.org/10.1088/1742-6596/68/1/012009, 2016-01-27)
    We show that when the antisymmetric Kalb-Ramond field is included in the Randall-Sundrum scenario, although the hierarchy problem can be solved, it requires an extreme fine tuning of the Kalb-Ramond field (about 1 part ...
  • Das, Saurya; Shankaranarayanan, S. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeInternational Centre for Theoretical Physicshttps://doi.org/10.1103/PhysRevD.73.121701, 2016-01-25)
    We revisit the problem of finding the entanglement entropy of a scalar field on a lattice by tracing over its degrees of freedom inside a sphere. It is known that this entropy satisfies the area law – entropy proportional ...
  • Ahmadi, Morteza; Das, Saurya; Shankaranarayanan, S. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeInternational Centre for Theoretical Physicshttps://doi.org/10.1139/p06-002, 2016-01-25)
    It is known that the entanglement entropy of a scalar field, found by tracing over its degrees of freedom inside a sphere of radius R, is proportional to the area of the sphere (and not its volume). This suggests that ...
  • Das, Saurya; Gegenberg, Jack (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeUniversity of New Brunswickhttps://doi.org/10.1007/s10714-008-0619-3, 2016-01-25)
    We derive general conditions under which geodesics of stationary spacetimes resemble trajectories of charged particles in an electromagnetic field. For large curvatures (analogous to strong magnetic fields), the quantum ...
  • 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 ...
  • Ali, Ahmed Farag; Das, Saurya (Arts and ScienceDepartment of Physics and AstronomyBenha UniversityUniversity of Lethbridge, 2016-01-20)
    It was shown recently that replacing classical geodesics with quantal (Bohmian) trajectories gives rise to a quantum corrected Raychaudhuri equation (QRE). Here we derive the second order Friedmann equations from the ...
  • Chemissany, Wissam; Das, Saurya; Ali, Ahmed Farag; Vagenas, Elias C. (Arts and ScienceDepartment of Physics and AstronomyKatholieke Universiteit LeuvenUniversity of LethbridgeAcademy of Athenshttps://doi.org/10.1088/1475-7516/2011/12/017, 2016-01-19)
    We examine effects of the Generalized Uncertainty Principle, predicted by various theories of quantum gravity to replace the Heisenberg’s uncertainty principle near the Planck scale, on post inflation preheating in ...
  • Das, Saurya; Mann, R. B. (Arts and ScienceDepartment of Physics and AstronomyUniversity of LethbridgeUniversity of Waterloo, 2016-01-19)
    Almost all theories of Quantum Gravity predict modifications of the Heisenberg Uncertainty Principle near the Planck scale to a so-called Generalized Uncertainty Principle (GUP). Recently it was shown that the GUP gives ...
  • Basilakos, Spyros; Das, Saurya; Vagenas, Elias C. (Arts and ScienceDepartment of Physics and AstronomyAcademy of AthensUniversity of Lethbridgehttps://doi.org/10.1088/1475-7516/2010/09/027, 2016-01-19)
    We investigate the effects of Quantum Gravity on the Planck era of the universe. In particular, using different versions of the Generalized Uncertainty Principle and under specific conditions we find that the main Planck ...
  • Das, Saurya; Vagenas, Elias C. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeAcademy of Athenshttps://doi.org/10.1139/P08-105, 2016-01-18)
    Various theories of Quantum Gravity argue that near the Planck scale, the Heisenberg Uncertainty Principle should be replaced by the so called Generalized Uncertainty Principle (GUP).We show that the GUP gives rise to ...
  • 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; Shankaranarayanan, S. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeMax-Planck-Institut für Gravitationphysikhttps://doi.org/10.1088/0264-9381/24/20/022, 2016-01-06)
    Understanding the area-proportionality of black hole entropy (the ‘Area Law’) from an underlying fundamental theory has been one of the goals of all models of quantum gravity. A key question that one asks is: where are ...