162 citations · 369 across the 37 of their papers we have counts for
38 papers
Quaternion Weyl Transform and some uniqueness results
Rupak Kumar Dalai, Somnath Ghosh, R. K. Srivastava
In this article, we study the boundedness and several properties of the quaternion Wigner transform. Using the quaternion Wigner transform as a tool, we define the quaternion Weyl…
Spherical means on Métivier groups and support theorem
Rupak Kumar Dalai, Somnath Ghosh, R. K. Srivastava
Let be the space of continuous functions on the annulus in whose -twisted spherical mean, in the set up of the Métivier group, vanishes over…
Unbounded Weyl transform on the Euclidean motion group and Heisenberg motion group
Somnath Ghosh, R. K. Srivastava
In this article, we define Weyl transform on second countable type - locally compact group and as an operator on we prove that the Weyl transform is compact when…
Exploring Unconventional Features Of Light Dynamics In Aubrey-Andre-Harper Model Based Quasi-periodic Optical Lattices
Suman Dey, Nikhil Ranjan Das, Somnath Ghosh
We report an Aubrey-Andre-Harper (AAH) model based quasi-periodic lossless evanescently coupled waveguide lattice to study the unconventional physics of light localization. We pres…
Hosting exceptional points in 1D photonic bandgap waveguide for mode engineering
Sibnath Dey, Somnath Ghosh
We report a planar 1D photonic bandgap waveguide exhibiting four second-order exceptional points (EP2s). The interactions between the selective pairs of supported quasi-guided TE m…
Exotic light dynamics around a fourth order exceptional point
Sibnath Dey, Arnab Laha, Somnath Ghosh
The physics of exceptional point (EP) singularities, has been a key to a wide range of unique physical applications in open systems. In this context, the mutual interactions among…
Photonic Crystal Based Ultra-Sensitive Interferometric Sensor with Spatial Resolution up to 1 nm
Snehashis Sadhukhan, Arnab Laha, Abhijit Biswas +1
We report a very high precision interferometric sensor with resolution up to ~λ/1024, exploiting hollow photonic bandgap waveguide-based geometry for the first time. Here sensing h…
Nonadiabatic Modal Dynamics Around a Third-order Exceptional Point in a planar waveguide
Sibnath Dey, Arnab Laha, Somnath Ghosh
Dynamical parametric encirclement around an Exceptional Point (EP) and corresponding asymmetric state transfer phenomenon have attracted considerable attention recently. In this co…
Third-order Exceptional Point and Successive Switching among Three States in a Degenerate Optical Microcavity
Arnab Laha, Dinesh Beniwal, Sibnath Dey +2
One of the most intriguing topological features of open systems is exhibiting exceptional point (EP) singularities. Apart from the widely explored second-order EPs (EP2s), the expl…
Ultra-sensitive Light Confinement Driven by Multiple Bound States in the Continuum
Harsh K. Gandhi, Arnab Laha, Somnath Ghosh
We propose a unique framework to study the topological properties of an optical bound state in the continuum(BIC). We employ the interactions between proximity resonances undergoin…
Higher order topological degeneracies and towards unique successive state-switching in a four-level open system
Sayan Bhattacherjee, Harsh K. Gandhi, Arnab Laha +1
The physics of topological singularities, namely exceptional points (EPs), has been a key to wide range of intriguing and unique physical effects in non-Hermitian systems. In this…
Nonlinearity Induced Anomalous Mode Collapsing and Non-chiral Asymmetric Mode Switching around multiple Exceptional Points
Sibnath Dey, Arnab Laha, Somnath Ghosh
The dynamical encirclement around a second order exceptional point (EP) and corresponding chirality driven nonadiabatic modal dynamics have attracted enormous attention in the topo…
Towards Hosting Bound State in Continuum in Specialty Optical Microcavity
Harsh K. Gandhi, Arnab Laha, Somnath Ghosh
We exploit the interaction between supported proximity resonances in an open non-uniformly pumped optical microcavity to host a Bound State in Continuum (BIC). Using the modeling o…
Exceptional Point and Toward Mode Selective Optical Isolation
Arnab Laha, Sibnath Dey, Harsh K. Gandhi +2
Dynamical encirclement of an Exceptional Point (EP) and corresponding time-asymmetric mode evolution properties due to breakdown in adiabatic theorem have been a key to range of ex…
Optical waveguide hosting multiple exceptional points: Toward selective mode conversion
Arnab Laha, Harsh K. Gandhi, Sibnath Dey +3
We investigate the astonishing physical aspects of Exceptional Points (EPs) in a 1D planar few-mode optical waveguide. The waveguide hosts four quasi-guided modes. Here interaction…
Benedicks-Amrein-Berthier theorem for the Heisenberg motion group and quaternion Heisenberg group
Somnath Ghosh, R. K. Srivastava
Since is a Gelfand pair, an exact analogue of the Heisenberg group result due to Narayanan and Ratnakumar is not possible for the Heisenberg motio…
Heisenberg uniqueness pairs for the Fourier transform on the Heisenberg group
Somnath Ghosh, R. K. Srivastava
In this article, we prove that (unit sphere, non-harmonic cone) is a Heisenberg uniqueness pair for the symplectic Fourier transform on We derive that spheres as wel…
Non-adiabatic Modal Dynamics around Exceptional Points in an All-Lossy Dual-Mode Optical Waveguide: Towards Chirality Driven Asymmetric Mode-Conversion
Arnab Laha, Abhijit Biswas, Somnath Ghosh
We report a 1D planar optical waveguide with transverse distribution of inhomogeneous loss profile, which exhibits an exceptional point (EP). The waveguide hosts two leaky resonant…
Propagation and asymmetric behavior of optical pulses through time-dynamic loss-gain assisted media
Piyali Biswas, Harsh K. Gandhi, Vaibhab Mishra +1
We report an asymmetric behavior of optical pulses during their propagation through a time-varying linear optical medium. The refractive index of the medium is considered to be var…
Origin of third order exceptional singularities and its signature in successive state conversion
Sayan Bhattacherjee, Arnab Laha, Somnath Ghosh
We report an open three-state perturbed system with quasi-statically varying Hamiltonian depending on the topological parameters. The effective system hosts two second order except…
Realization of Third Order Exceptional Singularities in a Three level non-Hermitian System: Towards Cascaded State Conversion
Sayan Bhattacherjee, Arnab Laha, Somnath Ghosh
The appearance of topological singularities, namely exceptional points (EPs) is an intriguing feature of parameter-dependent open quantum or wave systems. EPs are the special type…
Net-charge fluctuation in Au+Au collisions at energies available at the Facility for Antiproton and Ion Research using the UrQMD model
Somnath Ghosh, Provash Mali, Amitabha Mukhopadhyay
We have studied the dynamical fluctuation of net-charge of hadrons produced in Au+Au collisions at energies that in near future will be available at the Facility for Antiproton and…
Radial flow in a multi phase transport model at FAIR energies
Soumya Sarkar, Provash Mali, Somnath Ghosh +1
Azimuthal distributions of radial velocities of charged hadrons produced in nucleus-nucleus collisions are compared with the corresponding azimuthal distribution of charged…
Three State Quantum System Exhibiting Third Order Exceptional Singularities and Flip-of-States
Sayan Bhattacherjee, Arnab Laha, Somnath Ghosh
A quantum inspired open optical system is mathematically implemented with an analogous three state non-Hermitian Hamiltonian exhibiting two special avoided-resonance-crossings; whe…