20 citations · 45 across the 20 of their papers we have counts for
20 papers
A fast solver for ill-conditioned linear systems using randomized stable solutions of its blocks
Suvendu Kar, Murugesan Venkatapathi
We present an enhanced version of the row-based randomized block-Kaczmarz method to solve a linear system of equations. This improvement makes use of a regularization during block…
An Optimal Least-Square Solver For Scaled Partial-Isometric Linear Systems
Suvendu Kar, Murugesan Venkatapathi
We present an direct least-squares solver for linear systems with a scaled partial isometry. The proposed algorithm is also useful when the system is block dia…
Efficient approximations of matrix multiplication using truncated decompositions
Suvendu Kar, Hariprasad M., Sai Gowri J. N. +1
We exploit the truncated singular value decomposition and the recently proposed circulant decomposition for an efficient first-order approximation of the multiplication of large de…
Approximations for modeling light scattering by spheres with uncertainty in physical parameters
Akif Khan, Murugesan Venkatapathi
Uncertainty in physical parameters can make the solution of forward or inverse light scattering problems in astrophysical, biological, and atmospheric sensing applications, cost pr…
A short study comparing countries on the quality of response to the Covid-19 pandemic
Thilakam Venkatapathi, Murugesan Venkatapathi
Background: We estimate the overall quality of response to the Covid-19 pandemic in the first 18 months, using a small number of known parameters and a proposed method that is reas…
Radiative decay of an emitter due to non-Markovian interactions with dissipating matter
Kritika Jain, Murugesan Venkatapathi
It is known that the more tractable Markovian models of coupling suited for weak interactions may overestimate the Rabi frequency notably when applied to the strong-coupling regime…
Circulant decomposition of a matrix and the eigenvalues of Toeplitz type matrices
Hariprasad M., Murugesan Venkatapathi
We begin by showing that any matrix can be decomposed into a sum of circulant matrices with periodic relaxations on the unit circle. This decomposition is orthogon…
Role of Rabi oscillations in radiative states due to the fully absorbing smaller plasmonic nanoparticles
Kritika Jain, Murugesan Venkatapathi
The modified radiative and non-radiative states due to the weak coupling of an emitter with other resonant objects (Purcell effect), can be recast as a quantum interference of the…
An O(n) algorithm for generating uniform random vectors in n-dimensional cones
Arun I., Murugesan Venkatapathi
Unbiased random vectors i.e. distributed uniformly in n-dimensional space, are widely applied and the computational cost of generating a vector increases only linearly with n. On t…
An algorithm for estimating volumes and other integrals in dimensions
Arun I., Murugesan Venkatapathi
The computational cost in evaluation of the volume of a body using numerical integration grows exponentially with dimension of the space . The most generally applicable algorith…
Emitter-Vacuum coupling through a leaky nanostructure and the role of dynamics in density of optical states
Kritika Jain, Murugesan Venkatapathi
We show a break down of the conventional partition of optical states into its radiative and non-radiative parts. Large divergence of experimental observations from current theory i…
Error estimators and their analysis for CG, Bi-CG and GMRES
Puneet Jain, Krishna Manglani, Murugesan Venkatapathi
The demands of accuracy in measurements and engineering models today, renders the condition number of problems larger. While a corresponding increase in the precision of floating p…
Fano type transparency and other multimode interference effects in all-dielectric nanoshells
Srishti Garg, Murugesan Venkatapathi
Recently, the coupling of two different modes of a homogeneous plasmonic particle and their sharply varying spectra were elucidated as Fano resonances; an 'interference' of two spa…
Cooperative spontaneous emission induced by smaller metal nanoparticles
George J. Vathakkattil, M. Praveena, J. K. Basu +1
We present a study showing cooperative behavior of light emitting quantum dots at room temperature, with large increases in radiative decay rates and efficiencies, in the presence…
Semi-analytical solutions for eigenvalue problems of chains and periodic graphs
Hariprasad M., Murugesan Venkatapathi
We first show the existence and nature of convergence to a limiting set of roots for polynomials in a three-term recurrence of the form a…
Estimation of errors in iterative solutions of a non-symmetric linear system
Aashish Vishwakarma, Murugesan Venkatapathi
Estimation of actual errors from the residue in iterative solutions is necessary for efficient solution of large problems when their condition number is much larger than one. Such…
Collective eigenstates of emission in an N-entity heterostructure and the evaluation of its Green tensors and self-energy components
Murugesan Venkatapathi
Our understanding of emission from a collection of emitters strongly interacting among them and also with other polarizable matter in proximity has been approximated by independent…
Non-stationary extremal eigenvalue approximations in iterative solutions of linear systems and estimators for relative error
Divya Anand Subba, Murugesan Venkatapathi
Non-stationary approximations of the final value of a converging sequence are discussed, and we show that extremal eigenvalues can be reasonably estimated from the CG iterates with…
Radiative and non-radiative effects of a substrate on localized plasmon resonance of particles
Murugesan Venkatapathi, Abhay K. Tiwari
Experiments have shown strong effects of some substrates on the localized plasmons of metallic nano particles but they are inconclusive on the affecting parameters. Here we have us…
Emitter near an arbitrary body: Purcell effect, optical theorem and the Wheeler-Feynman absorber
Murugesan Venkatapathi
The altered spontaneous emission of an emitter near an arbitrary body can be elucidated using an energy balance of the electromagnetic field. From a classical point of view it is t…