Browsing Physics & Astronomy by Title

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  • Das, Saurya; Vagenas, Elias C. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeAcademy of Athenshttps://doi.org/10.1209/0295-5075/96/50005, 2015-12-22)
    We argue that a quantum aether is consistent with the principle of relativity and can provide an economical way of having an invariant quantum gravity or Planck scale. We also show that it may change the effective scale ...
  • 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; 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 (Arts and ScienceDepartment of PhysicsUniversity of Lethbridgehttps://doi.org/10.1103/PhysRevD.89.084068, 2015-12-22)
    We compute quantum corrections to the Raychaudhuri equation by replacing classical geodesics with quantal (Bohmian) trajectories, and show that they prevent focusing of geodesics, and the formation of conjugate points. ...
  • 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; Dey, Anindya; SenGupta, Soumitra (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeHarish-Chandra Research InstituteIndian Association for the Cultivation of Sciencehttps://doi.org/10.1088/0264-9381/23/20/L01, 2015-12-16)
    We re-examine the fine tuning problem of the Higgs mass, when an antisymmetric two form Kalb-Ramond (KR) field is present in the bulk of a Randall-Sundrum (RS) braneworld. Taking into account the back-reaction of the KR ...
  • Alberto, Pedro; Das, Saurya; Vagenas, Elias C. (Arts and ScienceDepartment of Physics and AstronomyUniversidade de CoimbraUniversity of LethbridgeAcademy of Athenshttps://doi.org/10.1016/j.physleta.2011.02.030, 2015-12-15)
    We generalize the work of Alberto, Fiolhais and Gil and solve the problem of a Dirac particle confined in a 3-dimensional box. The non-relativistic and ultra-relativistic limits are considered and it is shown that the ...
  • 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; 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 ...
  • van der Wiel, M. H. D.; Naylor, David A.; Kamp, I.; Ménard, F.; Thi, W.-F.; Woitke, P.; Olofsson, G.; Pontoppidan, K. M.; Di Francesco, J.; Glauser, A. M.; Greaves, J. S.; Ivison, R. J. (Oxford University PressArts and ScienceDepartment of Physics and AstronomyUniversity of LethbridgeUniversity of GroningenCNRSUniversité Grenoble AlpesUniversity of St. AndrewsStockholm UniversitySpace Telescope Science InstituteNational Research Council CanadaUniversity of VictoriaETH ZurichEuropean Southern ObservatoryUniversity of Edinburghhttps://doi.org/10.1093/mnras/stu1462, 2014)
    Molecular gas constitutes the dominant mass component of protoplanetary discs. To date, these sources have not been studied comprehensively at the longest far-infrared and shortest submillimetre wavelengths. This paper ...
  • Bernard-Salas, J.; Habart, E.; Arab, H.; Abergel, A.; Dartois, E.; Martin, P.; Bontemps, S.; Joblin, C.; White, G. J.; Bernard, J.-P.; Naylor, David A. (EDP SciencesArts and ScienceDepartment of Physics & AstronomyInstitut d'Astrophysique SpatialeCanadian Institute for Theoretical AstrophysicsLaboratoire d'Astrophysique de BordeauxUniversité de ToulouseIRAPOpen UniversityRutherford Appleton LaboratoryUniversity of Lethbridge10.1051/0004-6361/201118083, 2012)
    Context. The energetics in photo-dissociation regions (PDRs) are mainly regulated by the balance between the heating from the photo-electric effect acting on dust grains, and the cooling via the copious emission of photons ...
  • 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; Dey, Anindya; SenGupta, Soumitra (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeUniversity of Texas at AustinIndian Association for the Cultivation of Sciencehttps://doi.org/10.1209/0295-5075/83/51002, 2015-12-15)
    We generalise the RS braneworld model by taking into account a general stringy bulk containing the scalar dilaton field and the two-form Kalb-Ramond field, apart from gravity. Assuming small fluctuations around a RS ...
  • Greve, T. R.; Leonidaki, I.; Xilouris, E.M.; Weiss, A.; Zhang, Z.-Y.; van der Werf, P.; Aalto, S.; Armus, L.; Diaz-Santos, T.; Evans, A.S.; Fischer, J.; Gao, Y.; Gonzalez-Alfonso, E.; Harris, A.; Henkel, C.; Mekjerink, R.; Naylor, David A.; Smith, H.A.; Spaans, M.; Stacey, G.J.; Veilleux, S.; Walter, F. (American Astronomical Society, 2014)
    We present FIR[50-300 um]-CO luminosity relations (i.e., log Lfir = a log L’co + B) for the full CO rotational ladder from J = 1 – 0 up to J = 13 -12 for a sample of 62 local (z <= 0.1) (Ultra) Luminous Infrared Galaxies ...
  • 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. ...
  • Hopwood, R.; Polehampton, E. T.; Valtchanov, I.; Swinyard, B. M.; Fulton, T.; Lu, N.; Marchili, N.; van der Wiel, M. H. D.; Benielli, D.; Imhof, P.; Baluteau, J.-P.; Pearson, C.; Clements, D. L.; Griffin, M. J.; Lim, T. L.; Makiwa, G.; Naylor, David A.; Noble, G.; Puga, E.; Spencer, L. D. (Oxford University PressArts and ScienceDepartment of Physics and AstronomyImperial College LondonRutherford Appleton LaboratoryUniversity of LethbridgeHerschel Science CentreUniversity College LondonNASA Herschel Science CentreIAPS-INAFUniversity of CopenhagenUniversité d'Aix-MarseilleBlue Sky SpectroscopyThe Open UniversityUniversity of OxfordCardiff UniversityUniversity of British Columbiahttps://doi.org/10.1093/mnras/stv353, 2015)
    A systematic programme of calibration observations was carried out to monitor the performance of the Spectral and Photometric Imaging REceiver (SPIRE) Fourier Transform Spectrometer (FTS) instrument on board the Herschel ...
  • van der Wiel, M. H. D.; Naylor, David A.; Makiwa, Gibion; Satt, M.; Abergel, A. (EDP SciencesArts and ScienceDepartment of Physics & AstronomyUniversity of CopenhagenUniversity of LethbridgeUniversity of RomeUniversité Paris-Saclay10.1051/0004-6361/201628512, 2016)
    Context. The HF molecule has been proposed as a sensitive tracer of diffuse interstellar gas, while at higher densities its abundance could be influenced heavily by freeze-out onto dust grains. Aims. We investigate the spatial ...
  • Faizal, Mir; Khalil, Mohammed M.; Das, Saurya (SpringerOpenArts and ScienceDepartment of Physics and AstronomyUniversity of WaterlooAlexandria UniversityUniversity of Lethbridgehttps://doi.org/10.1140/epjc/s10052-016-3884-4, 2016)
    Motivated by the Generalized Uncertainty Principle, covariance, and a minimum measurable time, we propose a deformation of the Heisenberg algebra and show that this leads to corrections to all quantum mechanical systems. ...
  • Das, Saurya; Vagenas, Elias C. (Arts and ScienceDepartment of PhysicsUniversity of LethbridgeAcademy of Athenshttps://doi.org/10.1103/PhysRevLett.101.221301, 2015-12-22)
    We show that the existence of a minimum measurable length and the related Generalized Uncertainty Principle (GUP), predicted by theories of Quantum Gravity, influence all quantum Hamiltonians. Thus, they predict quantum ...