Abstract Details
| Name: SAFIQUL ISLAM Affiliation: PDF, Harish Chandra Research Institute, Allahabad Conference ID: ASI2017_1209 Title : Wormholes supported by two non-interacting fluids Authors and Co-Authors : Dr.Farook Rahaman Professor,Department of Mathematics, Jadavpur University, Kolkata,WestBengal, India Ph:(09051195731) Email:rahaman@associates.iucaa.in 2.Dr.Saibal Roy Associate Professor, Department of Physics, Government College of Engineering & Ceramic Technology, Kolkata West Bengal, India. Ph(09163169796) Email:saibal@associates.iucaa.in Abstract Type : Poster Abstract Category : General Relativity and Cosmology Abstract : Title:Wormholes supported by two non-interacting fluids: In this paper, we have extended the cut-and-paste technique to two copies of a charged black hole.This has been done in generalized dilaton-axion gravity which was inspired by low energy string theory.This was done following the work of Visser (1989) who proposed a theoretical method for constructing a new class of traversable Lorentzian wormholes from black-hole spacetimes by surgical grafting of two Schwarzschild spacetimes. The main benefit in Visser's approach is that it minimizes the amount of exotic matter required. Here a new matter source that supplies fuel to construct wormhole spacetime has been provided. The exact wormhole solutions are found in the model having, besides real matter, an anisotropic dark energy. The novel point here seems to be the interpretation in terms of two fluids, which is more or less arbitrary. It has been shown that the exotic matters that are the necessary ingredients for wormhole physics violate null and weak energy conditions (NEC and WEC) but obey strong energy condition (SEC) marginally. The effective mass of the wormhole up to 4 km throat radius has been calculated as 0.561 times 1 Solar Mass ( 1 Solar Mass =1.475 km) . Though the wormhole comprises of exotic matters yet the effective mass remains positive. This implies that for an observer sitting at large distance could not distinguish the gravitational nature between wormhole and a compact mass M. The total gravitational energy of the wormhole is found as, Eg= 1.9397 (geometric unit of length). Since, Eg > 0, there is a repulsion around the throat which is very much expected for valid construction of a wormhole. Some physical features like visual structure, proper radial distance, energy conditions, equilibrium conditions are discussed. The equilibrium stage can be achieved due to the combined effect of pressure anisotropic, gravitational and hydrostatic forces, i.e F(g)+F(h)+F(a)=0. The three different forces acting on fluid elements in static equilibrium are plotted against the radial distance, r. The flare-out conditions have been studied and the effective gravitational mass, total gravitational energy and traversability conditions are also briefly discussed. Graphs of energy conditions and proper radial distance, l(r),are also plotted. To travel through a wormhole, the tidal gravitational forces experienced by a traveler must be reasonably small. In our model the above condition is automatically satisfied, the traveler feels a zero gravitational acceleration since ν = 0.The wormhole model provided here with anisotropic dark energy and real matter is fascinating in several aspects and hence very promising one. [Published in Astrophysics and Space Science, 346, 245-252,(2013)] |