Results for "Indranil Chakraborty"

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Design of a Low Voltage Analog-to-Digital Converter using Voltage Controlled Stochastic Switching of Low Barrier NanomagnetsMar 04 2018May 23 2018The inherent stochasticity in many nano-scale devices makes them prospective candidates for low-power computations. Such devices have been demonstrated to exhibit probabilistic switching between two stable states to achieve stochastic behavior. Recently, ... More
Geodesics in exact plane wave spacetimes and the memory effectJan 31 2019Recently [Phys. Rev. D 96, 064013(2017)], it has been shown how the displacement and velocity memory effects can be analysed by studying geodesics in the exact plane gravitational wave line element. In our work here, we provide simple and largely analytical ... More
A Photonic In-Memory Computing primitive for Spiking Neural Networks using Phase-Change MaterialsAug 03 2018Oct 24 2018Spiking Neural Networks (SNNs) offer an event-driven and more biologically realistic alternative to standard Artificial Neural Networks based on analog information processing. This can potentially enable energy-efficient hardware implementations of neuromorphic ... More
Discretization based Solutions for Secure Machine Learning against Adversarial AttacksFeb 08 2019Feb 11 2019Adversarial examples are perturbed inputs that are designed (from a deep learning network's (DLN) parameter gradients) to mislead the DLN during test time. Intuitively, constraining the dimensionality of inputs or parameters of a network reduces the 'space' ... More
Discretization based Solutions for Secure Machine Learning against Adversarial AttacksFeb 08 2019Adversarial examples are perturbed inputs that are designed (from a deep learning network's (DLN) parameter gradients) to mislead the DLN during test time. Intuitively, constraining the dimensionality of inputs or parameters of a network reduces the 'space' ... More
Technology Aware Training in Memristive Neuromorphic Systems based on non-ideal Synaptic CrossbarsNov 24 2017The advances in the field of machine learning using neuromorphic systems have paved the pathway for extensive research on possibilities of hardware implementations of neural networks. Various memristive technologies such as oxide-based devices, spintronics ... More
Energy-Efficient Memories using Magneto-Electric Switching of FerromagnetsJan 27 2017Voltage driven magneto-electric (ME) switching of ferro-magnets has shown potential for future low-energy spintronic memories. In this paper, we first analyze two different ME devices viz. ME-MTJ and ME-XNOR device with respect to writability, readability ... More
Principle bundles admitting a holomorphic structureJan 18 1996Let $M$ be a compact connected K\"ahler manifold and let ${\E}_{l-1}$ be the smallest term in the Harder-Narasimhan filtration of its tangent bundle. Let $G$ be an affine algebraic reductive group over $\C$. We prove the following result: If $M$ satisfies ... More
Stable principal bundles and reduction of structure groupAug 23 2006Let $E_G$ be a stable principal $G$--bundle over a compact connected Kaehler manifold, where $G$ is a connected reductive linear algebraic group defined over the complex numbers. Let $H\subset G$ be a complex reductive subgroup which is not necessarily ... More
On Kaehler structures over symmetric products of a Riemann surfaceJun 19 2011Feb 29 2012Given a positive integer $n$ and a compact connected Riemann surface $X$, we prove that the symmetric product $S^n(X)$ admits a Kaehler form of nonnegative holomorphic bisectional curvature if and only if $\text{genus}(X) \leq 1$. If $n$ is greater than ... More
Vacuum Tunneling by Cosmic StringsFeb 05 1997We consider vacuum tunneling of a new kind where the false vacua are not translationally invariant, but have topological defects that break some of their translational symmetries. In the particular case where the topological defects are cosmic strings, ... More
A remark on the jet bundles over the projective lineJul 03 1996This is a footnote of a recent interesting work of Cohen, Manin and Zagier, where they, among other things, produce a natural isomorphism between the sheaf of (n-1)-th order jets of the n-th tensor power of the tangent bundle of a Riemann surface equipped ... More
Fisher Information: Quantum Uncertainty RelationNov 17 2005The paper deals with the reformulation of quantum uncertainty relation involving position and momentum of a particle on the basis of the Kerridge measure of inaccuracy and the Fisher information.
Secret Broadcasting of GHZ type stateDec 04 2008Apr 05 2010Here we described a protocol by which one can broadcast GHZ-type states secretly. We have done this with the help of a cloning machine followed by subsequent measurements. We also made a comparative study of the amount of residual tangle present in these ... More
Single qubit, two qubit gates and no signalling principleMay 22 2006Jan 31 2009In this work we investigate that whether one can construct single and two qubit gates for arbitrary quantum states from the principle of no signalling. We considered the problem for Pauli gates, Hadamard gate, C-Not gate.
The imaginary time Path Integral and non-time-reversal-invariant- saddle points of the Euclidean ActionOct 19 1997Apr 14 1998We discuss new bounce-like (but non-time-reversal-invariant-) solutions to Euclidean equations of motion, which we dub boomerons. In the Euclidean path integral approach to quantum theories, boomerons make an imaginary contribution to the vacuum energy. ... More
Parabolic principal Higgs bundlesJun 08 2008In ``Ramified G-bundles as parabolic bundles'' (J. Ramanujan Math. Soc. (2003) Vol. 18) with Balaji and Nagaraj we introduced the ramified principal bundles. The aim here is to define the Higgs bundles in the ramified context.
Moduli space of $G$-connections on an elliptic curveApr 08 2015Let $X$ be a smooth complex elliptic curve and $G$ a connected reductive affine algebraic group defined over $\mathbb C$. Let ${\mathcal M}_X(G)$ denote the moduli space of topologically trivial algebraic $G$--connections on $X$, that is, pairs of the ... More
Estimating Vacuum Tunneling RatesOct 18 1996Jan 30 1997We show that in Euclidean field theories that have bounce solutions, the bounce with the least action is the global minimum of the action in an open space of field configurations. A rigorous upper bound on the minimal bounce action can therefore be obtained ... More
Semistability and restrictions of tangent bundle to curvesJan 27 2009We consider all complex projective manifolds X that satisfy at least one of the following three conditions: 1. There exists a pair $(C ,\varphi)$, where $C$ is a compact connected Riemann surface and $\varphi : C\to X$ a holomorphic map, such that the ... More
Teleportation via a mixture of a two qubit subsystem of a N-qubit W and GHZ stateJan 28 2009Dec 08 2009In this work we study a state which is a random mixture of a two qubit subsystem of a $N$-qubit W state and GHZ state. We analyze several possibilities like separability criterion (Peres-Horodecki criterion [14,15]), non violation of Bell's inequality ... More
Partial Swapping, Unitarity and No-signallingJun 27 2007It is a well known fact that an quantum state $|\psi(\theta,\phi)>$ is represented by a point on the Bloch sphere, characterized by two parameters $\theta$ and $\phi$. In a recent work we already proved that it is impossible to partially swap these quantum ... More
Baryogenesis from Cosmic Strings at the Electroweak ScaleApr 19 1996Oct 01 1996We explore the viability of baryogenesis from light scalar decays after the electroweak phase transition. A minimal model of this kind is constructed with new CP violating interactions involving a heavy fourth family. The departure from thermal equilbrium ... More
Semidirect products and invariant connectionsFeb 18 2015Let $S$ be a complex reductive group acting holomorphically on a complex Lie group $N$ via holomorphic automorphisms. Let $K(S)\subset S$ be a maximal compact subgroup. The semidirect product $G := N\rtimes K(S)$ acts on $N$ via biholomorphisms. We give ... More
Connections on a parabolic principal bundle, IIFeb 10 2007In \cite{Bi2} (Canad. Jour. Math. Vol. 58) we defined connections on a parabolic principal bundle. While connections on usual principal bundles are defined as splittings of the Atiyah exact sequence, it was noted in \cite{Bi2} that the Atiyah exact sequence ... More
Homogeneous principal bundles and stabilityMar 25 2009Let G/P be a rational homogeneous variety, where P is a parabolic subgroup of a simple and simply connected linear algebraic group G defined over an algebraically closed field of characteristic zero. A homogeneous principal bundle over G/P is semistable ... More
On the stratified vector bundlesJul 15 2008The stratified vector bundles on a smooth variety defined over an algebraically closed field $k$ form a neutral Tannakian category over $k$. We investigate the affine group--scheme corresponding to this neutral Tannakian category.
On the moduli space of holomorphic G-connections on a compact Riemann surfaceApr 08 2019Let $X$ be a compact connected Riemann surface of genus at least two and $G$ a connected reductive complex affine algebraic group. The Riemann--Hilbert correspondence produces a biholomorphism between the moduli space ${\mathcal M}_X(G)$ parametrizing ... More
Capacitively Driven Global Interconnect with Magnetoelectric Switching Based Receiver for Higher Energy EfficiencyFeb 26 2018We propose capacitively driven low-swing global interconnect circuit using a receiver that utilizes magnetoelectric (ME) effect induced magnetization switching to reduce the energy consumption. Capacitively driven wire has recently been shown to be effective ... More
Efficient Hybrid Network Architectures for Extremely Quantized Neural Networks Enabling Intelligence at the EdgeFeb 01 2019The recent advent of `Internet of Things' (IOT) has increased the demand for enabling AI-based edge computing. This has necessitated the search for efficient implementations of neural networks in terms of both computations and storage. Although extreme ... More
Toward Fast Neural Computing using All-Photonic Phase Change Spiking NeuronsApr 01 2018Aug 28 2018The rapid growth of brain-inspired computing coupled with the inefficiencies in the CMOS implementations of neuromrphic systems has led to intense exploration of efficient hardware implementations of the functional units of the brain, namely, neurons ... More
8T SRAM Cell as a Multi-bit Dot Product Engine for Beyond von-Neumann ComputingFeb 22 2018Oct 16 2018Large scale digital computing almost exclusively relies on the von-Neumann architecture which comprises of separate units for storage and computations. The energy expensive transfer of data from the memory units to the computing cores results in the well-known ... More
A study of charged cylindrical Gravitational collapse with dissipative fluidFeb 20 2017The present works deals with gravitational collapse of cylindrical viscous heat conducting anisotropic fluid following the work of Misner and Sharp. Using Darmois matching conditions, the dynamical equations are derived and the effect of charge and dissipative ... More
Gravitational collapse of cylindrical anisotropic fluid: A source of gravitational wavesFeb 19 2016Mar 05 2016The present work deals with dynamics of gravitational collapse with cylindrical symmetry as developed by Misner and Sharp. The interior collapsing anisotropic cylindrical perfect fluid is matched to an exterior vacuum cylindrically symmetric space-time ... More
Electrically Modulated Thin Film Dynamics Controlling Bubble Manipulation in Microfluidic ConfinementMay 12 2013Dec 03 2014Thin film dynamics and associated instability mechanisms have triggered a wide range of scientific innovations, as attributed to their abilities of creating fascinating patterns over small scales. Here, we demonstrate a new thin film instability phenomenon ... More
Trajectory around a spherically symmetric non-rotating black holeSep 04 2011Trajectory of a test particle or a photon around a general spherical black hole is studied and bending of light trajectory is investigated. Pseudo-Newtonian gravitational potential describing the gravitational field of the black hole is determined and ... More
Gravitational collapse of dissipative fluid as a source of gravitational wavesFeb 24 2016Gravitational collapse of cylindrical anisotropic fluid has been considered in analogy with the work of Misner and Sharp. Using Darmois matching conditions, the interior cylindrical dissipative fluid (in the form of shear viscosity and heat flux )is matched ... More
On the cardinality of unique range sets with weight oneJul 19 2018Two meromorphic functions $f$ and $g$ are said to share the set $S\subset \mathbb{C}\cup\{\infty\}$ with weight $l\in\mathbb{N}\cup\{0\}\cup\{\infty\}$, if $E_{f}(S,l)=E_{g}(S,l)$ where $$E_{f}(S,l)=\bigcup\limits_{a \in S}\{(z,t) \in \mathbb{C}\times\mathbb{N}~ ... More
Probing $(g-2)_μ$ at the LHC in the paradigm of R-parity violating MSSMNov 28 2015Apr 06 2016The measurement of the anomalous magnetic moment of the muon exhibits a long standing discrepancy compared to the Standard model prediction. In this paper, we concentrate on this issue in the framework of $R$-parity violating Minimal supersymmetric standard ... More
Module-less Synthesis on Cyberphysical Digital Microfluidic Biochip Ensuring Error Detection and Routing Performance OptimizationApr 08 2018Digital Microfluidic Biochips consist of Two Dimensional microarrays that are integrated with different healthcare related cyberphysical systems and expected to be used extensively in near future. Thus, faster and error-free synthesis techniques need ... More
Differential geometry of moduli spaces of quiver bundlesJun 05 2016Let P be a parabolic subgroup of a simple affine algebraic group G defined over C and X a compact connected K\"ahler manifold. L. \'Alvarez-C\'onsul and O. Garc\'ia-Prada associated to these a quiver Q and representations of Q into holomorphic vector ... More
Commuting elements in reductive groups and Higgs bundles on abelian varietiesMay 15 2013Let G be a connected real reductive algebraic group, and let K be a maximal compact subgroup of G. We prove that the conjugation orbit space Hom(Z^{2d},K)/K is a strong deformation retract of the space Hom(Z^{2d},G)/G of equivalence classes of representations ... More
Holomorphic Cartan geometry on manifolds with numerically effective tangent bundleJan 21 2011Let X be a compact connected Kaehler manifold such that the holomorphic tangent bundle TX is numerically effective. A theorem of Demailly, Peternell and Schenider says that there is a finite unramified Galois covering M --> X, a complex torus T, and a ... More
On the fundamental group of a variety with quotient singularitiesNov 24 2013Let k be a field, and let {\pi}:\tilde{X} -> X be a proper birational morphism of irreducible k-varieties, where \tilde{X} is smooth and X has at worst quotient singularities. When the characteristic of k is zero, a theorem of Koll\'ar in [Ko1] says that ... More
Holomorphic Riemannian metric and fundamental groupApr 06 2018Nov 07 2018We prove that compact complex manifolds bearing a holomorphic Riemannian metric have infinite fundamental group.
Parabolic k-ample bundlesMar 07 2011We construct projectivization of a parabolic vector bundle and a tautological line bundle over it. It is shown that a parabolic vector bundle is ample if and only if the tautological line bundle is ample. This allows us to generalize the notion of a k-ample ... More
Unitary representations of the fundamental group of OrbifoldsAug 27 2009Feb 06 2012There is a well known bijective correspondence between isomorphism classes of polystable vector bundles $E$ with $c_i(E)=0$ for $i\geq 1$ on a smooth complex projective variety and equivalence classes of unitary representations of the fundamental group ... More
On the relative ConnectionsFeb 27 2019We investigate relative connections on a sheaf of modules. A sufficient condition is given for the existence of a relative holomorphic connection on a holomorphic vector bundle over a complex analytic family. We show that the relative Chern classes of ... More
Invariant connections and invariant holomorphic bundles on homogeneous manifoldsMay 15 2013Nov 17 2013Let $X$ be a differentiable manifold endowed with a transitive action $\alpha:A\times X\longrightarrow X$ of a Lie group $A$. Let $K$ be a Lie group. Under suitable technical assumptions, we give explicit classification theorems, in terms of explicit ... More
Effect of plasma composition on magnetized outflowsApr 12 2019In this paper, we study magnetized winds described by variable adiabatic index equation of state in Paczy\'{n}ski \& Wiita pseudo-Newtonian potential. We identify the flow solutions with the parameter space of the flow. We also confirm that the physical ... More
On the Kähler structures over Quot schemesJan 29 2014Let $S^n(X)$ be the $n$-fold symmetric product of a compact connected Riemann surface $X$ of genus $g$ and gonality $d$. We prove that $S^n(X)$ admits a K\"ahler structure such that all the holomorphic bisectional curvatures are nonpositive if and only ... More
Superposition and Entanglement: Pillars of Quantum Information ProcessingNov 16 2005Jan 14 2007This article discusses the important primitives of Superposition and Entanglement in Quantum Information Processing from physics point of view. System of spin-1/2 particles has been considered which presents itself as a logical and conceptual candidate ... More
Binary Cosmic StringsJul 14 1995The properties of cosmic strings have been investigated in detail for their implications in early-universe cosmology. Although many variations of the basic structure have been discovered, with implications for both the microscopic and macroscopic properties ... More
Higgs bundles on Sasakian manifoldsJul 25 2016We extend the Donaldson-Corlette-Hitchin-Simpson correspondence between Higgs bundles and flat connections on compact K\"ahler manifolds to compact quasi-regular Sasakian manifolds. A particular consequence is the translation of restrictions on K\"ahler ... More
Fractional Order AGC for Distributed Energy Resources Using Robust OptimizationNov 29 2016The applicability of fractional order (FO) automatic generation control (AGC) for power system frequency oscillation damping is investigated in this paper, employing distributed energy generation. The hybrid power system employs various autonomous generation ... More
A construction of Chern classes of parabolic vector bundlesSep 14 2012Given a parabolic vector bundle, we construct for it a projectivization and tautological line bundle. These are analogs of the projectivization and tautological line bundle for an usual vector bundle. Using these we give a construction of the parabolic ... More
When Darwin meets Lorenz: Evolving new chaotic attractors through genetic programmingSep 27 2014May 03 2015In this paper, we propose a novel methodology for automatically finding new chaotic attractors through a computational intelligence technique known as multi-gene genetic programming (MGGP). We apply this technique to the case of the Lorenz attractor and ... More
Limits on quantum deletion from no signaling principleMay 19 2017One of the fundamental restrictions that quantum mechanics imposes is the "No deletion Theorem" which tells us that given two identical unknown quantum states, it is impossible to delete one of them. But nevertheless if not perfect, people have tried ... More
On the Kähler structures over Quot schemes, IIMar 30 2015Let $X$ be a compact connected Riemann surface of genus $g$, with $g \geq 2$, and let ${\mathcal O}_X$ denote the sheaf of holomorphic functions on $X$. Fix positive integers $r$ and $d$ and let ${\mathcal Q}(r,d)$ be the Quot scheme parametrizing all ... More
Some moduli stacks of symplectic bundles on a curve are rationalApr 08 2006Sep 17 2008Let C be a smooth projective curve of genus at least 2 over a field k. Given a line bundle L on C, we consider the moduli stack of rank 2n vector bundles E on C endowed with a nowhere degenerate symplectic form $b: E \otimes E \to L$ up to scalars. We ... More
Rigidity of holomorphic maps between fiber spacesSep 16 2013Dec 19 2013In the study of holomorphic maps, the term "rigidity" refers to certain types of results that give us very specific information about a general class of holomorphic maps owing to the geometry of their domains or target spaces. Under this theme, we begin ... More
Study of Non-Holonomic Deformations of Non-local integrable systems belonging to the Nonlinear Schrodinger familyApr 21 2019The non-holonomic deformations of non-local integrable systems belonging to the Nonlinear Schrodinger family are studied using the Bi-Hamiltonian formalism as well as the Lax pair method. The non-local equations are first obtained by symmetry reductions ... More
Ice Shelves as Floating Channel Flows of Viscous Power-Law FluidsOct 30 2013Dec 07 2013We attempt to better understand the flow of marine ice sheets. Treating ice as a viscous shear-thinning power law fluid, we develop an asymptotic (late-time) theory in two cases - the presence or absence of contact with sidewalls. Most real-world situations ... More
A Torelli type theorem for exp-algebraic curvesJun 21 2016An exp-algebraic curve consists of a compact Riemann surface $S$ together with $n$ equivalence classes of germs of meromorphic functions modulo germs of holomorphic functions, $\HH = \{ [h_1], \cdots, [h_n] \}$, with poles of orders $d_1, \cdots, d_n ... More
Effects of Fluid Composition on Spherical Flows around Black HolesDec 14 2008Steady, spherically symmetric, adiabatic accretion and wind flows around non-rotating black holes were studied for fully ionized, multi-component fluids, which are described by a relativistic equation of state (EoS). We showed that the polytropic index ... More
On the rational homotopy type of a moduli space of vector bundles over a curveMay 19 2006Oct 23 2007We study the rational homotopy of the moduli space ${\mathcal N}_X$ of stable vector bundles of rank two and fixed determinant of odd degree over a compact connected Riemann surface $X$ of genus $g\geq 2$. The symplectic group $Aut(H_1(X,{\mathbb Z}))=Sp(2g,{\mathbb ... More
An alternative approach for compatibility of two discrete conditional distributionsNov 02 2017Conditional specification of distributions is a developing area with increasing applications. In the finite discrete case, a variety of compatible conditions can be derived. In this paper, we propose an alternative approach to study the compatibility ... More
Morse theory for the space of Higgs G-bundlesFeb 05 2010Fix a $C^\infty$ principal $G$--bundle $E^0_G$ on a compact connected Riemann surface $X$, where $G$ is a connected complex reductive linear algebraic group. We consider the gradient flow of the Yang--Mills--Higgs functional on the cotangent bundle of ... More
Equivariant bundles and connectionsNov 27 2016Let $X$ be a connected complex manifold equipped with a holomorphic action of a complex Lie group $G$. We investigate conditions under which a principal bundle on $X$ admits a $G$--equivariance structure.
Principal bundles over a real algebraic curveAug 01 2011Sep 25 2012Let X be a compact connected Riemann surface equipped with an anti-holomorphic involution \sigma. Let G be a connected complex reductive affine algebraic group, and let \sigma_G be a real form of G. We consider holomorphic principal G-bundles on X satisfying ... More
Torelli theorem for the moduli spaces of connections on a Riemann surfaceDec 12 2005Feb 05 2007Let $(X,x_0)$ be any one--pointed compact connected Riemann surface of genus $g$, with $g\geq 3$. Fix two mutually coprime integers $r>1$ and $d$. Let ${\mathcal M}_X$ denote the moduli space parametrizing all logarithmic $\text{SL}(r,{\mathbb C})$--connections, ... More
Fundamental Group of Moduli Spaces of RepresentationsMay 14 2014Jan 20 2015Let S be a surface of genus g with n points removed, G a connected Lie group, and X(G) the moduli space of representations of the fundamental group of S into G. We compute the fundamental group of X(G) when n>0 and G is a real or complex reductive algebraic ... More
Atiyah sequences, connections and Chern-Weil theory for algebraic and differentiable stacksNov 19 2013Nov 26 2013We construct connections and characteristic forms for principal bundles over groupoids and stacks in the differentiable, holomorphic and algebraic category using Atiyah sequences associated to transversal tangential distributions.
Inverses of structured vector bundlesJan 31 2015Apr 22 2015We prove that structured vector bundles whose holonomies lie in GL(N,C), SO(N,C), or Sp(2N,C) have structured inverses. This generalizes a theorem of Simons and Sullivan.
The Nori fundamental gerbe of tame stacksFeb 25 2015Sep 09 2015Given an algebraic stack, we compare its Nori fundamental group with that of its coarse moduli space. We also study conditions under which the stack can be uniformized by an algebraic space.
Monopoles on Sasakian Three-foldsDec 12 2014We consider monopoles with singularities of Dirac type on quasiregular Sasakian three-folds fibering over a compact Riemann surface $\Sigma$, for example the Hopf fibration $S^3\longrightarrow S^2$. We show that these correspond to holomorphic objects ... More
On semistable principal bundles over a complex projective manifold, IISep 25 2009Let (X, \omega) be a compact connected Kaehler manifold of complex dimension d and E_G a holomorphic principal G-bundle on X, where G is a connected reductive linear algebraic group defined over C. Let Z (G) denote the center of G. We prove that the following ... More
Matter Chern Simons Theories in a Background Magnetic FieldApr 16 2019We study large $N$ 2+1 dimensional fermions in the fundamental representation of an $SU(N)_k$ Chern Simons gauge group in the presence of a uniform background magnetic field for the $U(1)$ global symmetry of this theory. The magnetic field modifies the ... More
Estimation of mass outflow rates from viscous relativistic accretion discs around black holesMay 03 2016We investigated flow in Schwarzschild metric, around a non-rotating black hole and obtained self-consistent accretion - ejection solution in full general relativity. We covered the whole of parameter space in the advective regime to obtain shocked, as ... More
Multi-standard programmable baseband modulator for next generation wireless communicationSep 09 2010Considerable research has taken place in recent times in the area of parameterization of software defined radio (SDR) architecture. Parameterization decreases the size of the software to be downloaded and also limits the hardware reconfiguration time. ... More
H_1-semistability for projective groupsMar 09 2014We initiate the study of the asymptotic topology of groups that can be realized as fundamental groups of smooth complex projective varieties with holomorphically convex universal covers (these are called here as holomorphically convex groups). We prove ... More
A note on real algebraic groupsNov 12 2013The efficacy of using complexifications to understand the structure of real algebraic groups is demonstrated. In particular the following results are proved: a) If L is an algebraic subgroup of a connected real algebraic group G such that the complexification ... More
Chaotic multi-objective optimization based design of fractional order PIλDμ controller in AVR systemMay 08 2012Jan 05 2013In this paper, a fractional order (FO) PI{\lambda}D\mu controller is designed to take care of various contradictory objective functions for an Automatic Voltage Regulator (AVR) system. An improved evolutionary Non-dominated Sorting Genetic Algorithm II ... More
On the Mixed H2/H-infinity Loop Shaping Trade-offs in Fractional Order Control of the AVR SystemNov 17 2013May 12 2014This paper looks at frequency domain design of a fractional order (FO) PID controller for an Automatic Voltage Regulator (AVR) system. Various performance criteria of the AVR system are formulated as system norms and is then coupled with an evolutionary ... More
Design of Hybrid Regrouping PSO-GA based Sub-optimal Networked Control System with Random Packet LossesJun 16 2013In this paper, a new approach has been presented to design sub-optimal state feedback regulators over Networked Control Systems (NCS) with random packet losses. The optimal regulator gains, producing guaranteed stability are designed with the nominal ... More
General relativistic two-temperature accretion solutions for spherical flows around black holesNov 14 2018Matter falling onto black holes is hot, fully ionized and has to be necessarily transonic. Since the electrons are responsible for radiative cooling via processes like synchrotron, bremsstrahlung and inverse-Compton, therefore the electron gas and proton ... More
On the logarithmic connections over curvesMay 11 2012We study two different actions on the moduli spaces of logarithmic connections over smooth complex projective curves. Firstly, we establish a dictionary between logarithmic orbifold connections and parabolic logarithmic connections over the quotient curve. ... More
A Torelli type theorem for exp-algebraic curvesJun 21 2016May 28 2018An exp-algebraic curve consists of a compact Riemann surface $S$ together with $n$ equivalence classes of germs of meromorphic functions modulo germs of holomorphic functions, $\HH = \{ [h_1], \cdots, [h_n] \}$, with poles of orders $d_1, \cdots, d_n ... More
Anti-holomorphic involutive isometry of hyper-Kähler manifolds and branesOct 24 2014We study complex Lagrangian submanifolds of a compact hyper-K\"ahler manifold and prove two results: (a) that an involution of a hyper-K\"ahler manifold which is antiholomorphic with respect to one complex structure and which acts non-trivially on the ... More
Automorphisms of the generalized quot schemesJan 18 2016Given a compact connected Riemann surface $X$ of genus $g \geq 2$, and integers $r\geq 2$, $d_p > 0$ and $d_z > 0$, in \cite{BDHW}, a generalized quot scheme ${\mathcal Q}_X(r,d_p,d_z)$ was introduced. Our aim here is to compute the holomorphic automorphism ... More
Vector bundles on Sasakian manifoldsSep 23 2008Mar 20 2009We investigate the analog of holomorphic vector bundles in the context of Sasakian manifolds.
Generalization of a criterion for semistable vector bundlesApr 25 2008It is known that a vector bundle E on a smooth projective curve Y defined over an algebraically closed field is semistable if and only if there is a vector bundle F on Y such that the cohomologies of E\otimes F vanish. We extend this criterion for semistability ... More
Universal vector bundle over the realsAug 31 2009Mar 10 2010Let X_R be a geometrically irreducible smooth projective curve, defined over R, such that X_R does not have any real points. Let X= X_R\times_R C be the complex curve. We show that there is a universal real algebraic line bundle over X_R x Pic^d(X_R)$ ... More
Testing Gravity with wide binary stars like $α$ CentauriMay 31 2018Jan 23 2019We consider the feasibility of testing Newtonian gravity at low accelerations using wide binary (WB) stars separated by $\ge 3$ kAU. These systems probe the accelerations at which galaxy rotation curves unexpectedly flatline, possibly due to Modified ... More
The Escape Velocity Curve of the Milky Way in Modified Newtonian DynamicsAug 12 2017May 31 2018We determine the escape velocity from the Milky Way (MW) at a range of Galactocentric radii in the context of Modified Newtonian Dynamics (MOND). Due to its non-linear nature, escape is possible if the MW is considered embedded in a constant external ... More
Dynamical History Of The Local Group In $Λ$CDM $\rm{II}$ $-$ Including External Perturbers In 3DSep 14 2016Feb 02 2017We attempt to fit the observed radial velocities (RVs) of ${\,{\sim}\,}30$ Local Group (LG) galaxies using a 3D dynamical model of it and its immediate environment within the context of the standard cosmological paradigm, $\Lambda$CDM. This extends and ... More
Dynamical History of the Local Group in $Λ$CDMJun 24 2015Apr 13 2016The positions and velocities of galaxies in the Local Group (LG) measure the gravitational field within it. This is mostly due to the Milky Way (MW) and Andromeda (M31). We constrain their masses using distance and radial velocity (RV) measurements of ... More
Boundary terms of the Einstein-Hilbert actionJul 19 2016Mar 15 2017The Einstein-Hilbert action for general relativity is not well posed in terms of the metric $g_{ab}$ as a dynamical variable. There have been many proposals to obtain an well posed action principle for general relativity, e.g., addition of the Gibbons-Hawking-York ... More
Equilibrium configuration of perfect fluid orbiting around black holes in some classes of alternative gravity theoriesMay 09 2014Mar 10 2015The hydrodynamic behaviour of perfect fluid orbiting around black holes in spherically symmetric spacetime for various alternative gravity theories has been investigated. For this purpose we have assumed an uniform distribution for the angular momentum ... More
Signatures of two-dimensionalisation of 3D turbulence in presence of rotationJan 18 2007Apr 25 2007A reason has been given for the inverse energy cascade in the two-dimensionalised rapidly rotating 3D incompressible turbulence. For such system, literature shows a possibility of the exponent of wavenumber in the energy spectrum's relation to lie between ... More