Publications (100)
Cosmic optical activity from an inhomogeneous Kalb-Ramond field
Sayan Kar, Parthasarathi Majumdar, Soumitra SenGupta +1
The effects of introducing a harmonic spatial inhomogeneity into the Kalb-Ramond field, interacting with the Maxwell field according to a `string-inspired' proposal made in earlier…
Kinematics of deformable media
Anirvan Dasgupta, Hemwati Nandan, Sayan Kar
We investigate the kinematics of deformations in two and three dimensional media by explicitly solving (analytically) the evolution equations (Raychaudhuri equations) for the expan…
Born-Infeld gravity with a Brans-Dicke scalar
Soumya Jana, Sayan Kar
Recently proposed Born-Infeld (BI) theories of gravity assume a constant BI parameter (). However, no clear consensus exists on the sign and value of . Recalling the Brans-…
Quasinormal spectra of a wormhole family: overtone features and a parameter-controlled redshift
Abhisek Barman Maji, Sayan Kar
Though investigated extensively in the past, we take a detailed relook at the study of quasinormal modes (QNM) in a known family of wormholes (ultrastatic (), as well as…
Bulk phantom fields, increasing warp factors and fermion localisation
Ratna Koley, Sayan Kar
A bulk phantom scalar field (with negative kinetic energy) in a sine--Gordon type potential is used to generate an exact thick brane solution with an increasing warp factor. It is…
A simple analytic example of the gravitational wave memory effect
Indranil Chakraborty, Sayan Kar
We report an analytical example of the gravitational wave memory effect in exact plane wave spacetimes. A square pulse profile is chosen which gives rise to a curved wave region sa…
Scale Factor Duality and the Energy Condition Inequalities
Sayan Kar
We demonstrate, by a simple analysis, that cosmological line elements related by scale factor duality also exhibit a duality with respect to the conservation/violation of the Weak…
Pulse-induced memory-like effect in cyclotron motion?
Sayan Kar
We study how a charged particle moving in a uniform magnetic field along its standard circular path (cyclotron motion) reacts to a short-duration, homogeneous, uniform electric fie…
Radion stability and induced, on-brane geometries in an effective scalar-tensor theory of gravity
Sayan Kar, Sayantani Lahiri, Soumitra SenGupta
About a decade ago, using a specific expansion scheme, effective, on-brane scalar tensor theories of gravity were proposed by Kanno and Soda (Phys.Rev. {\bf D 66} 083506 ,(2002)) i…
Cosmology with decaying tachyon matter
A. Das, Shashikant Gupta, Tarun Deep Saini +1
We investigate the case of a homogeneous tachyon field coupled to gravity in a spatially flat Friedman-Robertson-Walker spacetime. Assuming the field evolution to be exponentially…
Revisiting a family of wormholes: geometry, matter, scalar quasinormal modes and echoes
Poulami Dutta Roy, S. Aneesh, Sayan Kar
We revisit a family of ultra-static Lorentzian wormholes which includes Ellis-Bronnikov spacetime as a special case. We first show how the required total matter stress energy (whic…
Evolution of geodesic congruences in a gravitationally collapsing scalar field background
Rajibul Shaikh, Sayan Kar, Anirvan DasGupta
The evolution of timelike geodesic congruences in a spherically symmetric, nonstatic, inhomogeneous spacetime representing gravitational collapse of a massless scalar field is stud…
Particle creation in the presence of a warped extra dimension
Suman Ghosh, Sayan Kar
Particle creation in spacetimes with a warped extra dimension is studied. In particular, we investigate the dynamics of a conformally coupled, massless scalar field in a five dimen…
Three dimensional Eddington--inspired Born--Infeld gravity: solutions
Soumya Jana, Sayan Kar
Three dimensional Eddington-inspired Born--Infeld gravity is studied with the goal of finding new solutions. Beginning with cosmology, we obtain analytical and numerical solutions…
Born-Infeld cosmology with scalar Born-Infeld matter
Soumya Jana, Sayan Kar
Cosmology in Eddington-inspired Born-Infeld gravity is investigated using a scalar Born-Infeld field (e.g. tachyon condensate) as matter. In this way, both in the gravity and matte…
Probing liquid surface waves, liquid properties and liquid films with light diffraction
Tarun Kr. Barik, Partha Roy Chaudhuri, Anushree Roy +1
Surface waves on liquids act as a dynamical phase grating for incident light. In this article, we revisit the classical method of probing such waves (wavelengths of the order of mm…
Shadows of a generic class of spherically symmetric, static spacetimes
Md. Golam Mafuz, Rishank Diwan, Soumya Jana +1
We explore the characteristics of shadows for a general class of spherically symmetric, static spacetimes, which may arise in general relativity or in modified theories of gravity.…
Confinement of test particles in warped spacetimes
Suman Ghosh, Hemwati Nandan, Sayan Kar
We investigate test particle trajectories in warped spacetimes with a thick brane warp factor, a cosmological on--brane line element and a time dependent extra dimension. The geode…
On higher order geometric and renormalisation group flows
Kartik Prabhu, Sanjit Das, Sayan Kar
Renormalisation group flows of the bosonic nonlinear Ï-model are governed, perturbatively, at different orders of α', by the perturbatively evaluated β--functions. In regions wh…
Gravitational lensing in braneworld gravity: formalism and applications
Supratik Pal, Sayan Kar
In this article, we develop a formalism which is different from the standard lensing scenario and is necessary for understanding lensing by gravitational fields which arise as solu…
Novel regular black holes: geometry, source and shadow
Anjan Kar, Sayan Kar
We propose a two-parameter, static and spherically symmetric regular geometry, which, for specific parameter values represents a regular black hole. The matter required to support…
Stable two--brane models with bulk tachyon matter
A. Das, Sayan Kar, Soumitra SenGupta
We explore the possibility of constructing stable, warped two--brane models which solve the hierarchy problem, with a bulk non--canonical scalar field (tachyon matter) as the sourc…
Modelling galaxy halos using dark matter with pressure
Somnath Bharadwaj, Sayan Kar
We investigate whether a dark matter with substantial amounts of pressure, comparable in magnitude to the energy density, could be a viable candidate for the constituent of dark ma…
Perturbations of spiky strings in flat spacetimes
Soumya Bhattacharya, Sayan Kar, Kamal L. Panigrahi
Perturbations of a class of semiclassical strings known today as spiky strings, are studied using the well-known Jacobi equations for small normal deformations of an embedded timel…
Geometry of deformations of branes in warped backgrounds
Supratik Pal, Sayan Kar
The `braneworld' (described by the usual worldvolume action) is a D dimensional timelike surface embedded in a N dimensional () warped, nonfactorisable spacetime. We first add…
Static spherisymmetric solutions, gravitational lensing and perihelion precession in Einstein--Kalb--Ramond theory
Sayan Kar, Soumitra SenGupta, Saurabh Sur
Static, spherically symmetric solutions of the Einstein--Kalb--Ramond (KR) field equations are obtained. Besides an earlier known exact solution, we also find an approximate, asymp…
Perturbations of spiky strings in AdS3
Soumya Bhattacharya, Sayan Kar, Kamal L. Panigrahi
Perturbations of a class of semiclassical spiky strings in three dimensional Anti-de Sitter (AdS) spacetime, are investigated using the well-known Jacobi equations for small, norma…
A note on the Einstein equation in string theory
Sayan Kar
We show, using purely classical considerations and logical extrapolation of results belonging to point particle theories, that the metric background field in which a string propaga…
A novel braneworld model with a bulk scalar field
Ratna Koley, Sayan Kar
We consider a new braneworld model with a bulk scalar field coupled to gravity. The bulk scalar action is inspired by the proposed low energy effective action around the tachyon va…
Bulk spacetimes for cosmological braneworlds with a time--dependent extra dimension
Suman Ghosh, Sayan Kar
We explore the possibilities of constructing bulk spacetimes in five dimensions for warped braneworld models with a spatially flat Friedmann-Robertson-Walker (FRW) line element on…
STRINGS IN A WORMHOLE BACKGROUND
Sayan Kar
Exact solutions of the string equations of motion in a specific Lorentzian wormhole background are obtained. These include both closed and open string configurations. Perturbations…
A note on the Penrose process in rotating regular black holes
Anjan Kar, Ayan Dey, Sayan Kar
We investigate the Penrose process of energy extraction in the context of rotating regular black holes. For the Neves-Saa class of regular black hole solutions, which includes the…
A simple mechanical analog of the field theory of tachyon matter
Sayan Kar
In this brief note we show that the zero dimensional version of the field theory of tachyon matter proposed by Sen, provides an action integral formulation for the motion of a part…
Displacement memory in regular black hole spacetimes
Ritwik Acharyya, Sayan Kar
Displacement memory, induced by a wave pulse in a regular black hole spacetime, is studied using geodesic (timelike) separation and geodesic deviation. The presence of the wave pul…
Closed strings in a class of pp-wave spacetimes and the memory effect
Ayan Dey, Sayan Kar
We study closed string evolution in the pp-wave spacetime assuming different pulse shapes (square and sech-squared) in the exact gravitational wave metric. It is shown that the sha…
Diverse regular spacetimes using a parametrised density profile
Anjan Kar, Sayan Kar
We explore the construction of diverse regular spacetimes (black holes and defects) in General Relativity (GR) using a generic parametrised density profile (the Dekel-Zhao profile)…
Focusing of timelike worldsheets in a theory of strings
Sayan Kar
An analysis of the generalised Raychaudhuri equations for string world sheets is shown to lead to the notion of focusing of timelike worldsheets in the classical Nambu-Goto theory…
Quantifying energy condition violations in traversable wormholes
Sayan Kar, Naresh Dadhich, Matt Visser
The `theoretical' existence of traversable Lorentzian wormholes in the classical, macroscopic world is plagued by the violation of the well--known energy conditions of General Rela…
Scalar kinks and fermion localisation in warped spacetimes
Ratna Koley, Sayan Kar
Scalar kinks propagating along the bulk in warped spacetimes provide a thick brane realisation of the braneworld. We consider here, a class of such exact solutions of the full Eins…
Path integrals and wavepacket evolution for damped mechanical systems
Dharmesh Jain, A. Das, Sayan Kar
Damped mechanical systems with various forms of damping are quantized using the path integral formalism. In particular, we obtain the path integral kernel for the linearly damped h…
Can the rotation of the dark matter halo of our galaxy be detected through its effect on the cosmic microwave background polarisation?
Partha Nag, Somnath Bharadwaj, Sayan Kar
The proposition that dark matter halos possess angular momentum, though widely accepted, is a theoretical prediction which has, till date, not been observationally verified. The gr…
A wormhole geometry from gravitational collapse
Soumya Chakrabarti, Sayan Kar
We discuss a proposal on how gravitational collapse of a NEC (Null Energy Condition) violating spherically symmetric fluid distribution can avoid the formation of a zero proper vol…
R=0 spacetimes and self-dual Lorentzian wormholes
Naresh Dadhich, Sayan Kar, Sailajananda Mukherji +1
A two-parameter family of spherically symmetric, static Lorentzian wormholes is obtained as the general solution of the equation , where , $Ï_t = (T_…
Schild's Null Strings in Flat and Curved Backgrounds
Sayan Kar
Schild's null (tensionless) strings are discussed in certain flat and curved backgrounds. We find closed, stationary, null strings as natural configurations existing on the horizon…
Exact solutions in two-dimensional string cosmology with back reaction
Sukanta Bose, Sayan Kar
We present analytic cosmological solutions in a model of two-dimensional dilaton gravity with back reaction. One of these solutions exhibits a graceful exit from the inflationary t…
Gravitational wave radiation from periodic orbits in regular black holes
Rishav Agrawal, Anjan Kar, Soumya Jana +1
Gravitational wave radiation from periodic orbits in some standard regular black hole spacetimes is studied, primarily using known methods (numerical and analytic). We demonstrate…
Wormholes with a warped extra dimension?
Sayan Kar
We investigate the role of a specifically warped extra dimension in constructing examples of higher dimensional spacetimes representing Lorentzian wormholes. The warping chosen is…
Focusing of branes in warped backgrounds
Sayan Kar
Branes are embedded surfaces in a given background (bulk) spacetime. Assuming a warped bulk, we investigate, in analogy with the case for geodesics, the notion of {\em focusing} of…
Classical and quantum mechanics of a particle on a rotating loop
Sayan Kar, Avinash Khare
The toy model of a particle on a vertical rotating circle in the presence of uniform gravitational/ magnetic fields is explored in detail. After an analysis of the classical mechan…
The Generalised Raychaudhuri Equations : Examples
Sayan Kar
Specific examples of the generalized Raychaudhuri Equations for the evolution of deformations along families of dimensional surfaces embedded in a background dimensional sp…
Generalised Hayward spacetimes: Geometry, matter and scalar quasinormal modes
Poulami Dutta Roy, Sayan Kar
Bardeen's 1968 idea of a regular black hole spacetime was revived by Hayward in 2006 through the construction of a new example of such a geometry. Later it was realised by Neves an…
Gravitational lensing by scalar-tensor wormholes and the energy conditions
Rajibul Shaikh, Sayan Kar
We study gravitational lensing by a class of zero Ricci scalar wormholes which arise as solutions in a scalar-tensor theory of gravity. An attempt is made to find a possible link b…
Geodesics and geodesic deviation in a two-dimensional black hole
Ratna Koley, Supratik Pal, Sayan Kar
We introduce an exactly solvable example of timelike geodesic motion and geodesic deviation in the background geometry of a well-known two-dimensional black hole spacetime. The eff…
Ricci flow of unwarped and warped product manifolds
Sanjit Das, Kartik Prabhu, Sayan Kar
We analyse Ricci flow (normalised/un-normalised) of product manifolds --unwarped as well as warped, through a study of generic examples. First, we investigate such flows for the un…
Generalised Raychaudhuri Equations for Strings and Membranes
Sayan Kar
A recent generalisation of the Raychaudhuri equations for timelike geodesic congruences to families of dimensional extremal, timelike, Nambu--Goto surfaces embedded in an d…
Geodesic congruences in warped spacetimes
Suman Ghosh, Anirvan Dasgupta, Sayan Kar
In this article, we explore the kinematics of timelike geodesic congruences in warped five dimensional bulk spacetimes, with and without thick or thin branes. Beginning with geodes…
Gravitational waves from quasinormal modes of a class of Lorentzian wormholes
S. Aneesh, Sukanta Bose, Sayan Kar
Quasinormal modes of a two-parameter family of Lorentzian wormhole spacetimes, which arise as solutions in a specific scalar-tensor theory associated with braneworld gravity, are o…
Traversable wormholes with arbitrarily small energy condition violations
Matt Visser, Sayan Kar, Naresh Dadhich
Traversable wormholes necessarily require violations of the averaged null energy condition; this being the definition of ``exotic matter''. However, the theorems which guarantee th…
Shadows in dyonic Kerr-Sen black holes
Soumya Jana, Sayan Kar
Black holes with dyonic charges in Einstein-Maxwell-dilaton-axion supergravity theory are revisited in the context of black hole shadows. We consider static as well as rotating (na…
Asymmetrically warped R=0 braneworlds
Sayan Kar
A new family of five dimensional, R=0 braneworlds with asymmetric warp factors is proposed. Beginning with the invariance of the Ricci scalar for the general class of asymmetricall…
Modelling Einstein cluster using Einasto profile
Ritwik Acharyya, Pritam Banerjee, Sayan Kar
We demonstrate a general relativistic approach to model dark matter halos using the Einstein cluster, with the matter stress-energy generated by collisionless particles moving on c…
Bach flows of product manifolds
Sanjit Das, Sayan Kar
We investigate various aspects of a geometric flow defined using the Bach tensor. Firstly, using a well-known split of the Bach tensor components for unwarped product manif…
The geometry of RG flows in theory space
Sayan Kar
Renormalisation Group (RG) flows in theory space (the space of couplings) are generated by a vector field -- the function. Using a specific metric ansatz in theory space and c…
Smooth double barriers in quantum mechanics
Avik Dutt, Sayan Kar
Quantum mechanical tunneling across smooth double barrier potentials modeled using Gaussian functions, is analyzed numerically and by using the WKB approximation. The transmission…
Braneworlds in six dimensions: new models with bulk scalars
Ratna Koley, Sayan Kar
Six dimensional bulk spacetimes with 3-- and 4--branes are constructed using certain non--conventional bulk scalars as sources. In particular, we investigate the consequences of ha…
New classes of black hole spacetimes in 2+1 gravity
Sukanta Bose, Naresh Dadhich, Sayan Kar
The electrogravity transformation is applied to the three-dimensional Einstein field equations to obtain new multi-parameter families of black hole solutions. The Bañados-Teitelbo…
Can extra dimensional effects replace dark matter ?
Supratik Pal, Somnath Bharadwaj, Sayan Kar
In the braneworld scenario, the four dimensional effective Einstein equation has extra terms which arise from the embedding of the 3-brane in the bulk. We show that in this modifie…
Evolving Lorentzian Wormholes
Sayan Kar, Deshdeep Sahdev
Evolving Lorentzian wormholes with the required matter satisfying the Energy conditions are discussed. Several different scale factors are used and the corresponding consequences d…
The Raychaudhuri equations: a brief review
Sayan Kar, Soumitra SenGupta
We present a brief review on the Raychaudhuri equations. Beginning with a summary of the essential features of the original article by Raychaudhuri and subsequent work of numerous…
Wormholes, the weak energy condition, and scalar-tensor gravity
Rajibul Shaikh, Sayan Kar
We obtain a large class of Lorentzian wormhole spacetimes in scalar-tensor gravity, for which the matter stress energy does satisfy the weak energy condition. Our constructions hav…
Born-Infeld gravity coupled to Born-Infeld electrodynamics
Soumya Jana, Sayan Kar
We investigate spherically symmetric, static spacetimes in Eddington-inspired Born-Infeld gravity coupled to Born-Infeld electrodynamics. The two constants, and which pa…
Higher order geometric flows on three dimensional locally homogeneous spaces
Sanjit Das, Kartik Prabhu, Sayan Kar
We analyse second order (in Riemann curvature) geometric flows (un-normalised) on locally homogeneous three manifolds and look for specific features through the solutions (analytic…
Stringy black holes and energy conditions
Sayan Kar
The energy condition inequalities for the matter stress energy comprised out of the dilaton and Maxwell fields in the dilaton-Maxwell gravity theories emerging out of string theory…
Can extra dimensional effects allow wormholes without exotic matter?
Sayan Kar, Sayantani Lahiri, Soumitra SenGupta
We explore the existence of Lorentzian wormholes in the context of an effective on-brane, scalar-tensor theory of gravity. In such theories, the timelike convergence condition, whi…
Does a Kalb-Ramond field make spacetime optically active
Sayan Kar, Parthasarathi Majumdar, Soumitra Sengupta +1
A spacetime with torsion produced by a Kalb-Ramond field coupled gravitationally to the Maxwell field, in accordance with a recent proposal by two of us (PM and SS), is argued to l…
de Sitter branes with a bulk scalar
Supratik Pal, Sayan Kar
We propose new braneworld models arising from a scalar field in the bulk. In these examples, the induced on--brane line element is de Sitter (or anti de Sitter) and the bulk (five…
Exact bound states in volcano potentials
Ratna Koley, Sayan Kar
Quantum mechanics in a one--parameter family of volcano potentials is investigated. After a discussion on their construction and classical mechanics, we obtain exact, normalisable…
Naked singularities in low energy, effective string theory
Sayan Kar
Solutions to the equations of motion of the low energy, effective field theory emerging out of compactified heterotic string theory are constructed by making use of the well-known…
Diffraction of light by interfering liquid surface waves
Tarun Kr. Barik, Anushree Roy, Sayan Kar
Interfering liquid surface waves are generated by electrically driven vertical oscillations of two or more equispaced pins immersed in a liquid (water). The corresponding intensity…
Generalised Raychaudhuri equations for strings in the presence of an antisymmetric tensor field
Sayan Kar
The generalised Raychaudhuri equations derived by Capovilla and Guven are exclusively for extremal, timelike Nambu--Goto membranes. In this article, we construct the corresponding…
Geometry of theory space and RG flows
Sayan Kar
The space of couplings of a given theory is the arena of interest in this article. Equipped with a metric ansatz akin to the Fisher information matrix in the space of parameters in…
Geodesic congruences in exact plane wave spacetimes and the memory effect
Indranil Chakraborty, Sayan Kar
Displacement and velocity memory effects in the exact, vacuum, plane gravitational wave line element have been studied recently by looking at the behaviour of pairs of geodesics or…
A new model with solitary waves: solution, stability and quasinormal modes
Surajit Basak, Poulami Dutta Roy, Sayan Kar
We construct solitary wave solutions in a dimensional massless scalar () field theory with a specially chosen potential . The equation governing perturbations abou…
Perturbations of giant magnons and single spikes in
Soumya Bhattacharya, Sayan Kar, Kamal L. Panigrahi
Perturbations of giant magnons and single spikes in a dimensional background spacetime are analysed. Using the form of the giant magnon solution in the…
Geodesic flows in rotating black hole backgrounds
Anirvan DasGupta, Hemwati Nandan, Sayan Kar
We study the kinematics of timelike geodesic congruences, in the spacetime geometry of rotating black holes in three (the BTZ) and four (the Kerr) dimensions. The evolution (Raycha…
Kundt geometries and memory effects in the Brans-Dicke theory of gravity
Siddhant Siddhant, Indranil Chakraborty, Sayan Kar
Memory effects are studied in the simplest scalar-tensor theory, the Brans--Dicke (BD) theory. To this end, we introduce, in BD theory, novel Kundt spacetimes (without and with gyr…
A note on spherically symmetric, static spacetimes in Kanno-Soda on-brane gravity
Sayan Kar, Sayantani Lahiri, Soumitra SenGupta
Spherically symmetric, static on-brane geometries in the Kanno-Soda (KS) effective scalar-tensor theory of on-brane gravity are discussed. In order to avoid brane collisions and/or…
Analog Raychaudhuri equation in mechanics
Rajendra Prasad Bhatt, Anushree Roy, Sayan Kar
Usually, in mechanics, we obtain the trajectory of a particle in a given force field by solving Newton's second law with chosen initial conditions. In contrast, through our work he…
Memory effects in Kundt wave spacetimes
Indranil Chakraborty, Sayan Kar
Memory effects in the exact Kundt wave spacetimes are shown to arise in the behaviour of geodesics in such spacetimes. The types of Kundt spacetimes we consider here are direct pro…
Can degenerate bound states occur in one dimensional quantum mechanics?
Sayan Kar, Rajesh R. Parwani
We point out that bound states, degenerate in energy but differing in parity, may form in one dimensional quantum systems even if the potential is non-singular in any finite domain…
New rotating Lorentzian wormhole spacetime
Anjan Kar, Soumya Jana, Sayan Kar
A rotating version of a known static, spherically symmetric, zero Ricci scalar Lorentzian wormhole is constructed. It turns out that for this given non-rotating geometry, the stand…
Splitting of degenerate states in one-dimensional quantum mechanics
Avik Dutt, Trisha Nath, Sayan Kar +1
A classic no-go theorem in one-dimensional quantum mechanics can be evaded when the potentials are unbounded below, thus allowing for novel parity-paired degenerate energy bound st…
The Ellis wormhole with `tachyon matter'
A. Das, Sayan Kar
The Ellis wormhole is known to be an exact solution of the Einstein--scalar system where the scalar field has negative kinetic energy (phantom). We show here that the same geometry…
Planetoid strings : solutions and perturbations
Sayan Kar, Swapna Mahapatra
A novel ansatz for solving the string equations of motion and constraints in generic curved backgrounds, namely the planetoid ansatz, was proposed recently by some authors. We cons…
Quasi-normal modes in a symmetric triangular barrier
Poulami Dutta Roy, Jagannath Das, Sayan Kar
Quasi-normal modes (QNMs) of the massless scalar wave in dimensions are obtained for a symmetric, finite, triangular barrier potential. This problem is exactly solvable, with…
Kinematics of trajectories in classical mechanics
Rajibul Shaikh, Sayan Kar, Anirvan DasGupta
In this paper, we show how the study of kinematics of a family of trajectories of a classical mechanical system may be unified within the framework of analysis of geodesic flows in…
Perturbative stability of catenoidal soap films
Soumya Jana, Sayan Kar
The perturbative stability of catenoidal soap films formed between parallel, equal radii, coaxial rings is studied using analytical and semi-analytical methods. Using a theorem on…
Kinematics of flows on curved, deformable media
Anirvan Dasgupta, Hemwati Nandan, Sayan Kar
In this article, we first investigate the kinematics of specific geodesic flows on two dimensional media with constant curvature, by explicitly solving the evolution (Raychaudhuri)…
Kinematics of geodesic flows in stringy black hole backgrounds
Anirvan Dasgupta, Hemwati Nandan, Sayan Kar
We study the kinematics of timelike geodesic congruences in two and four dimensions in spacetime geometries representing stringy black holes. The Raychaudhuri equations for the kin…
A curious variant of Bronnikov-Ellis spacetime
Sayan Kar
We explore a curious but simple variant of the Bronnikov-Ellis (BE) wormhole spacetime with a specific `red-shift function' (i.e. ) in the line element. The matter required…