Publications (245)
A way forward towards improvement of tensor force in \textit{pf}-shell
Kanhaiya Jha, Pawan Kumar, Shahariar Sarkar +2
In many shell model interactions, the tensor force monopole matrix elements often retain systematic trends originating in the bare tensor force. In this work, however, we note for…
Thermal Expansion Coefficient and Phonon Dynamics in Coexisting Allotropes of Monolayer WS2 Probed by Raman Scattering
Deepu Kumar, Birender Singh, Pawan Kumar +2
We report a comprehensive temperature dependent Raman measurements on three different phases of monolayer WS2 from 4K to 330K in a wide spectral range. Our studies revels the anoma…
Chemical interactions in active droplets
Prateek Dwivedi, Sobiya Ashraf, Pawan Kumar +2
Interactions among biologically active agents is facilitated by their self-generated chemical and hydrodynamic fields. In order to elucidate the pair-wise interactions between such…
Cost-Effective Cyber-Physical System Prototype for Precision Agriculture with a Focus on Crop Growth
Pawan Kumar, Hokeun Kim
In precision agriculture, integrating advanced technologies is crucial for optimizing plant growth and health monitoring. Cyber-physical system (CPS) platforms tailored to specific…
On random coarsening and its applications
Pawan Kumar
In this paper, we use the Poincare separation theorem for estimating the eigenvalues of the fine grid. We propose a randomized version of the algorithm where several different coar…
Effects of Spectral Normalization in Multi-agent Reinforcement Learning
Kinal Mehta, Anuj Mahajan, Pawan Kumar
A reliable critic is central to on-policy actor-critic learning. But it becomes challenging to learn a reliable critic in a multi-agent sparse reward scenario due to two factors: 1…
Population modelling of FRBs from intrinsic properties
Mukul Bhattacharya, Pawan Kumar
We present a method to estimate the source properties of FRBs from observations by assuming a fixed DM contribution from a MW-like host galaxy, pulse temporal broadening models for…
The late jet in gamma-ray bursts and its interactions with a supernova ejecta and a cocoon
Rongfeng Shen, Pawan Kumar, Tsvi Piran
Late X-ray flares observed in X-ray afterglows of gamma-ray bursts (GRBs) suggest late central engine activities at a few minuets to hours after the burst. A few unambiguously conf…
Exploring the epoch of hydrogen reionization using FRBs
Paz Beniamini, Pawan Kumar, Xiangcheng Ma +1
We describe three different methods for exploring the hydrogen reionization epoch using fast radio bursts (FRBs) and provide arguments for the existence of FRBs at high redshift (z…
On the generation of high energy photons detected by the Fermi Satellite from gamma-ray bursts
Pawan Kumar, Rodolfo Barniol Duran
Observations of gamma-ray bursts by the Fermi satellite, capable of detecting photons in a very broad energy band: 8keV to >300GeV, have opened a new window for the study of these…
The LIGO HET Response (LIGHETR) Project to Discover and Spectroscopically Follow Optical Transients Associated with Neutron Star Mergers
M. J. Bustamante-Rosell, Greg Zeimann, J. Craig Wheeler +20
The LIGO HET Response (LIGHETR) project is an enterprise to follow up optical transients (OT) discovered as gravitational wave merger sources by the LIGO/Virgo collaboration (LVC).…
Humanity's Last Exam
Long Phan, Alice Gatti, Ziwen Han +1144
Benchmarks are important tools for tracking the rapid advancements in large language model (LLM) capabilities. However, benchmarks are not keeping pace in difficulty: LLMs now achi…
Supercriticality of the dynamo limits the memory of the polar field to one cycle
Pawan Kumar, Bidya Binay Karak, Vindya Vashishth
The polar magnetic field precursor is considered to be the most robust and physics-based method for the prediction of the next solar cycle strength. However, to make a reliable pre…
Ultrathin Broadband Metasurface Superabsorbers from a van der Waals Semimetal
Adam D. Alfieri, Michael J. Motala, Michael Snure +8
Metamaterials and metasurfaces operating in the visible and near-infrared (NIR) offer a promising route towards next-generation photodetectors and devices for solar energy harvesti…
Coherent manipulation of four-level double lambda-like atomic system by a train of ultra-short few-cycle-optical pulses
Pawan Kumar, Amarendra K. Sarma
We have demonstrated that near complete coherence can be achieved in a four level double lambda-like systems using a train of ultra-short optical pulses. The effect of the Doppler…
Aggregation based on graph matching and inexact coarse grid solve for algebraic multigrid
Pawan Kumar
A graph based matching is used to construct aggregation for algebraic multigrid. Effects of inexact coarse grid solve is analyzed numerically for a highly discontinuous convection…
Riemannian Hamiltonian methods for min-max optimization on manifolds
Andi Han, Bamdev Mishra, Pratik Jawanpuria +2
In this paper, we study min-max optimization problems on Riemannian manifolds. We introduce a Riemannian Hamiltonian function, minimization of which serves as a proxy for solving t…
Nuclear forces and nuclear excited states
Pawan Kumar, Kanhaiya Jha
In this work, the role of the central, spin-force and tensor forces of two-nucleon interaction in building the first 2 and 4 states of 20 sd-shell nuclei is studied. Calcul…
Fast radio burst source properties and curvature radiation model
Pawan Kumar, Wenbin Lu, Mukul Bhattacharya
We use the observed properties of fast radio bursts (FRBs) and a number of general physical considerations to provide a broad-brush model for the physical properties of FRB sources…
Emergence of Order in Chemically Active Droplets: Temporal Dynamics and Collective Behavior
Sobiya Ashraf, Pawan Kumar, Prateek Dwivedi +3
Collective behaviors such as swarming, chemical signaling, and clustering are fundamental to biological microorganisms, enabling hierarchical colony formation, coordinated motion,…
Imaging topological defects in a non-collinear antiferromagnet
Aurore Finco, Angela Haykal, Stéphane Fusil +9
We report on the formation of topological defects emerging from the cycloidal antiferromagnetic order at the surface of bulk BiFeO crystals. Combining reciprocal and real-space…
The Emission Mechanism of Gamma-Ray Bursts: Identification via Optical-IR Slope Measurements
Bruce Grossan, Pawan Kumar, George F. Smoot
There is no consensus on the emission mechanism of -ray bursts (GRBs). A synchrotron model can produce -ray spectra with the empirical Band function form, from a piece-wise…
Steepening of Afterglow Decay for Jets Interacting with Stratified Media
Pawan Kumar, Alin Panaitescu
We calculate light-curves for Gamma-Ray Burst afterglows when material ejected in the explosion is confined to a jet which propagates in a medium with a power-law density profile.…
Mass Fall-back and Accretion in the Central Engine of Gamma-Ray Bursts
Pawan Kumar, Ramesh Narayan, Jarrett L. Johnson
We calculate the rate of in-fall of stellar matter on an accretion disk during the collapse of a rapidly rotating massive star, and estimate the luminosity of the relativistic jet…
Simulating droplet adhesion on superhydrophobic surfaces
Pawan Kumar, Joseph D. Berry
A numerical model is proposed to simulate the adhesion, compression, and subsequent detachment of a micro-liter droplet from a superhydrophobic surface composed of chemically homog…
Source depth for solar p-modes
Pawan Kumar, Sarbani Basu
Theoretically calculated power spectra are compares with observed solar p-mode velocity power spectra over a range of mode degree and frequency. The depth for the sources responsib…
Localized Helioseismic Constraints on Solar Structure
John N. Bahcall, Sarbani Basu, Pawan Kumar
Localized differences between the real sun and standard solar models are shown to be small. The sound speeds of the real and the standard model suns typically differ by less than 0…
X-ray Lines From Gamma-ray Bursts
Pawan Kumar, Ramesh Narayan
X-ray lines have been recently detected in the afterglows of a few gamma-ray bursts. We derive constraints on the physical conditions in the line-emitting gas, using as an example…
Direct Joule-Heated Non-Equilibrium Synthesis Enables High Performing Thermoelectrics
Chenguang Zhang, Jose Recatala-Gomez, Zainul Aabdin +20
High-throughput synthesis of bulk inorganic materials is crucial for accelerating functional materials discovery but is hindered by slow, energy-intensive solid-state methods. We i…
A Fast and Efficient Modern BERT based Text-Conditioned Diffusion Model for Medical Image Segmentation
Venkata Siddharth Dhara, Pawan Kumar
In recent times, denoising diffusion probabilistic models (DPMs) have proven effective for medical image generation and denoising, and as representation learners for downstream seg…
Faraday depolarization and induced circular polarization by multi-path propagation with application to FRBs
Paz Beniamini, Pawan Kumar, Ramesh Narayan
We describe how the observed polarization properties of an astronomical object are related to its intrinsic polarization properties and the finite temporal and spectral resolutions…
Tidal spin-up of stars in dense stellar cusps around massive black holes
Tal Alexander, Pawan Kumar
We show that main-sequence stars in dense stellar cusps around massive black holes are likely to rotate at a significant fraction of the centrifugal breakup velocity due to spin-up…
Efficient FPGA Implementation of Conjugate Gradient Methods for Laplacian System using HLS
Sahithi Rampalli, Natasha Sehgal, Ishita Bindlish +2
In this paper, we study FPGA based pipelined and superscalar design of two variants of conjugate gradient methods for solving Laplacian equation on a discrete grid; the first versi…
Role of Neutron Transfer in Sub-Barrier Fusion
Rudra N. Sahoo, Malika Kaushik, Arshiya Sood +11
Fusion excitation function of Cl + Te system is measured in the energy range around the Coulomb barrier and analyzed in the framework of the coupled-channels approac…
Electronic transport descriptors for the rapid screening of thermoelectric materials
Tianqi Deng, Jose Recatala-Gomez, Masato Ohnishi +11
The discovery of novel materials for thermoelectric energy conversion has potential to be accelerated by data-driven screening combined with high-throughput calculations. One way t…
Magnetospheric origin of a fast radio burst constrained using scintillation
Kenzie Nimmo, Ziggy Pleunis, Paz Beniamini +26
Fast radio bursts (FRBs) are micro-to-millisecond duration radio transients that originate mostly from extragalactic distances. The emission mechanism responsible for these high lu…
Fabry-Perot Interference, g-factor Anisotropy, and Gate-Tunable Quantum dot in Chiral Tellurium Nanowires
Suresh Ghimire, Mohammad Hafijur Rahaman, Nathan Tanner Sawyers +8
Chiral materials with strong spin-orbit coupling offer a unique platform for exploring the interplay between topology, chirality, and quantum transport yet the quantum coherent reg…
A Small, Rapid Optical-IR Response Gamma-Ray Burst Space Observatory (The NGRG)
Bruce Grossan, Pawan Kumar, Daniel Perley +1
Here we propose a new gamma-ray burst (GRB) mission, the Next Generation Rapid-Response GRB Observatory (NGRG). As with Swift, GRBs are initially located with a coded-mask X-ray ca…
Energetics and Luminosity Function of Gamma-ray Bursts
Pawan Kumar, Tsvi Piran
Gamma-ray bursts are believed to be some catastrophic event in which material is ejected at a relativistic velocity, and internal collisions within this ejecta produce the observed…
An Attention-Based Denoising Model for Diffusion Weighted Imaging
Prithviraj Verma, Pawan Kumar, Chandan Deshani +1
Diffusion-weighted imaging (DWI) is used for whole-body cancer screening, but it typically requires a long acquisition time. When the scan time is reduced, the image quality often…
Radiation Forces Constrain the FRB Mechanism
Pawan Kumar, Wenbin Lu
We provide constraints on Fast Radio Burst (FRB) models by careful considerations of radiation forces associated with these powerful transients. We find that the induced-Compton sc…
Monte Carlo Simulations of the Photospheric Process
Rodolfo Santana, Patrick Crumley, Roberto A. Hernandez +1
We present a Monte Carlo (MC) code we wrote to simulate the photospheric process and to study the photospheric spectrum above the peak energy. Our simulations were performed with a…
Simultaneous control of optical dipole force and coherence creation by super-Gaussian femtosecond pulses in lambda-like atomic systems
Pawan Kumar, Parvendra Kumar, Amarendra K. Sarma
We report a study on the optical dipole force on a beam of neutral three-level like atomic system induced by a femtosecond super-Gaussian pulse. We show that maximum coherence betw…
The Origins of Narrow Spectra of Fast Radio Bursts
Pawan Kumar, Yuanhong Qu, Bing Zhang
Observations find that some fast radio bursts (FRBs) have extremely narrow-band spectra, i.e., . We show that when the angular size of the emission region is large…
On the spectral redundancy of pineapple graphs
Pawan Kumar, S. Pirzada, Merajuddin +1
In this article, we explore the concept of spectral redundancy within the class of pineapple graphs, denoted as . These graphs are constructed by attaching …
Speculative Refinement: A Hybrid Autoregressive Diffusion Decoding Strategy and Its Behavior Across Benchmarks
Aditi Gupta, Neel Mishra, Kushagra Trivedi +1
How should we evaluate generation systems that combine autoregressive (AR) and diffusion decoding? We study this question through Speculative Refinement (SpecRef), a training-free…
HI Observations of two Molecular Clouds with Extremely Large Velocity Dispersions
Harald Riffert, Pawan Kumar, W. K. Huchtmeier
We have mapped two molecular clouds at (l, b) = (3.2 degrees, + 0.3 degrees) and (l, b) = (5.4 degrees, -0.5 degrees) in 21-cm line and continuum emission. These clouds show unusua…
Dispersion Measures of Fast Radio Bursts through the Epoch of Reionization
Joshua J. Ziegler, Paul R. Shapiro, Taha Dawoodbhoy +13
Dispersion measures (DM) of fast radio bursts (FRBs) probe the density of electrons in the intergalactic medium (IGM) along their lines-of-sight, including the average density vers…
Implications of a rapidly varying FRB in a globular cluster of M81
Wenbin Lu, Paz Beniamini, Pawan Kumar
A repeating source of fast radio bursts (FRBs) is recently discovered from a globular cluster of M81. Association to a globular cluster (or other old stellar systems) suggests that…
Linear polarization in gamma-ray burst prompt emission
Ramandeep Gill, Jonathan Granot, Pawan Kumar
Despite being hard to measure, GRB prompt -ray emission polarization is a valuable probe of the dominant emission mechanism and the outflow's composition and angular structure.…
Infrared emission from tidal disruption events --- probing the pc-scale dust content around galactic nuclei
Wenbin Lu, Pawan Kumar, Neal J. Evans
Recent UV-optical surveys have been successful in finding tidal disruption events (TDEs), in which a star is tidally disrupted by a supermassive black hole (BH). These TDEs release…
Hierarchical Sparse Plus Low Rank Compression of LLM
Pawan Kumar, Aditi Gupta
Modern large language models (LLMs) place extraordinary pressure on memory and compute budgets, making principled compression indispensable for both deployment and continued traini…
Distribution of Gamma-ray Burst Ejecta Energy with Lorentz Factor
Jonathan Granot, Pawan Kumar
The early X-ray afterglow for a significant number of gamma-ray bursts detected by the Swift satellite is observed to have a phase of very slow flux decline with time ($F_ν\propto…
Modification of tensor force in \textit{p}-shell effective interaction
Kanhaiya Jha, Pawan Kumar, Shahariar Sarkar +1
In many shell model interactions, the tensor force monopole matrix elements often retain systematic trends originating in the bare tensor force. However, in the present work, we fi…
Analysis of hierarchical SSOR for three dimensional isotropic model problem
Pawan Kumar
In this paper, we study a hierarchical SSOR (HSSOR) method which could be used as a standalone method or as a smoother for a two-grid method. It is found that the method leads to f…
Constraining the Structure of GRB Jets Through the Afterglow Light Curves
Jonathan Granot, Pawan Kumar
We investigate the effect that the structure of GRB jets has on the afterglow light curves for observers located at different viewing angles, , from the jet symmetry axis…
The Distribution of Burst Energy and Shock Parameters for Gamma-ray Bursts
Pawan Kumar
We calculate the statistical distribution of observed afterglow flux, in some fixed observed frequency band, and at some fixed observer time after the explosion () in two…
Monte Carlo simulations of Photospheric emission in relativistic outflows
Mukul Bhattacharya, Wenbin Lu, Rodolfo Santana +1
We study the spectra of photospheric emission from highly relativistic gamma-ray burst outflows using a Monte Carlo (MC) code. We consider the Comptonization of photons with a fast…
Role of individual components of two-nucleon interaction in nuclear matrix elements of and of Ca: Beyond the closure approximation
Shahariar Sarkar, Pawan Kumar, Kanhaiya Jha +1
In the present work, we examine the role of central (C), spin-orbit (SO) and tensor (T) components of two-nucleon interaction in the nuclear matrix elements (NMEs) of the two-neutr…
Solar cycle variability induced by stochastic fluctuations of BMR properties and at different amounts of dynamo supercriticality
Pawan Kumar
Understanding the irregular variation of the solar cycle is crucial due to its significant impact on global climates and the heliosphere. Since the polar magnetic field determines…
The large landscape of supernova, GRB and cocoon interactions
Fabio De Colle, Pawan Kumar, Peter Hoeflich
Long gamma ray bursts (LGRBs) are associated to the collapse of a massive star and the formation of a relativistic jet. As the jet propagates through the star, it forms an extended…
Machine learning and high-throughput robust design of P3HT-CNT composite thin films for high electrical conductivity
Daniil Bash, Yongqiang Cai, Vijila Chellappan +16
Combining high-throughput experiments with machine learning allows quick optimization of parameter spaces towards achieving target properties. In this study, we demonstrate that ma…
SCIMAT: Science and Mathematics Dataset
Neeraj Kollepara, Snehith Kumar Chatakonda, Pawan Kumar
In this work, we announce a comprehensive well curated and opensource dataset with millions of samples for pre-college and college level problems in mathematicsand science. A preli…
Overlay Space-Air-Ground Integrated Networks with SWIPT-Empowered Aerial Communications
Anuradha Verma, Pankaj Kumar Sharma, Pawan Kumar +1
In this article, we consider overlay space-air-ground integrated networks (OSAGINs) where a low earth orbit (LEO) satellite communicates with ground users (GUs) with the assistance…
Sports Business Administration and New Age Technology: Role of AI
Sahibpreet Singh, Pawan Kumar
This chapter explores the complexities of sports governance, taxation, dispute resolution, and the impact of digital transformation within the sports sector. This study identifies…
A general scheme for modeling gamma-ray burst prompt emission
Pawan Kumar, Erin McMahon, UT Austin
We describe a general method for modeling gamma-ray burst prompt emission. We find that for the burst to be produced via the synchrotron process unphysical conditions are required…
Can repeating and non-repeating FRBs be drawn from the same population?
Paz Beniamini, Pawan Kumar
Do all Fast Radio Burst (FRB) sources repeat? We present evidence that FRB sources follow a Zipf-like distribution, in which the number density of sources is approximately inversel…
An Optimal Block Diagonal Preconditioner for Heterogeneous Saddle Point Problems in Phase Separation
Pawan Kumar
The phase separation processes are typically modeled by Cahn-Hilliard equations. This equation was originally introduced to model phase separation in binary alloys, where phase sta…
On the Missing Energy Puzzle of Tidal Disruption Events
Wenbin Lu, Pawan Kumar
For the majority of the tidal disruption event (TDE) candidates, the observed energy in the optical/near-UV bands is of order 10^{51} erg. We show that this observed energy is smal…
Gas accretion in a clumpy disk with application to AGNs
Pawan Kumar
We analyze the collective gravitational interaction among gas clouds in the inner regions of galactic disks and find that it leads to accretion at a rate $\sim M_{mc}Ω(M_{mc}/M_t)…
On the orbital decay of the PSR J0045-7319 Binary
Pawan Kumar, Eliot J. Quataert
Recent observations of PSR J0045-7319, a radio pulsar in a close eccentric orbit with a massive main sequence B-star companion, indicate that the system's orbital period is decreas…
A universal energy distribution function for repeating fast radio bursts?
Wenbin Lu, Pawan Kumar
Assuming: fast radio bursts (FRBs) are produced by neutron stars at cosmological distances; FRB rate tracks core-collapse supernova rate; and all FRBs repeat with a universal energ…
GW170817 Most Likely Made a Black Hole
David Pooley, Pawan Kumar, J. Craig Wheeler +1
There are two outstanding issues regarding the neutron-star merger event GW170817: the nature of the compact remnant and the interstellar shock. The mass of the remnant of GW170817…
Accretion Models of Gamma-Ray Bursts
Ramesh Narayan, Tsvi Piran, Pawan Kumar
Many models of gamma-ray bursts (GRBs) involve accretion onto a compact object, usually a black hole, at a mass accretion rate of order a fraction of a solar mass per second. If th…
Giant gate-tunability of complex refractive index in semiconducting carbon nanotubes
Baokun Song, Fang Liu, Haonan Wang +11
Electrically-tunable optical properties in materials are desirable for many applications ranging from displays to lasing and optical communication. In most two-dimensional thin-fil…
The Role of Scintillation in Detecting HI Absorption in FRB Spectra
Om Gupta, Pawan Kumar, Paz Beniamini +1
The 21-cm absorption line of neutral hydrogen has been a long hypothesized observational feature of the spectra of Fast Radio Bursts (FRBs). The difficulties associated with detect…
Differential rotation enhanced dissipation of tides in the PSR J0045-7319 Binary
Pawan Kumar, Eliot J. Quataert
Recent observations of PSR J0045-7319, a radio pulsar in a close eccentric orbit with a massive B-star companion, indicate that the system's orbital period is decreasing on a times…
Tidal Excitation of Modes in Binary Systems with Applications to Binary Pulsars
Pawan Kumar, Chi On Ao, Eliot J. Quataert
We consider the tidal excitation of modes in a binary system of arbitrary eccentricity. For a circular orbit, the modes generally undergo forced oscillation with a period equal to…
High and uniform coherence creation in Doppler broadened double lambda-like atomic system by a train of femtosecond optical pulses
Amarendra K. Sarma, Pawan Kumar
We present a detailed analysis of coherence creation in a four level double lambda-like atomic system using a train of ultra-short few-cycle Gaussian pulses. The effect of the Dopp…
Wafer-scale growth of two-dimensional, phase-pure InSe
Seunguk Song, Sungho Jeon, Mahfujur Rahaman +12
Two-dimensional (2D) indium monoselenide (InSe) has attracted significant attention as a III-VI two-dimensional semiconductor (2D) with a combination of favorable attributes from I…
Scattering of Strong Radio Waves by Particles in Strongly Magnetized Plasmas and Implications for Fast Radio Bursts
Yuanhong Qu, Pawan Kumar
Fast Radio Bursts (FRBs) are millisecond-duration radio transients that are widely believed to originate within magnetar magnetospheres. Large-amplitude radio waves associated with…
The kinetic-energy bottleneck in Fast Radio Burst models
Paz Beniamini, Pawan Kumar
Most Fast Radio Burst (FRB) models invoke a two-step process in which energy released by the central engine is converted into particle kinetic energy and only subsequently radiated…
A flux-limited model for glioma patterning with hypoxia-induced angiogenesis
Pawan Kumar, Christina Surulescu
We propose a model for glioma patterns in a microlocal tumor environment under the influence of acidity, angiogenesis, and tissue anisotropy. The bottom-up model deduction eventual…
Fast current-induced skyrmion motion in synthetic antiferromagnets
Van Tuong Pham, Naveen Sisodia, Ilaria Di Manici +14
Magnetic skyrmions are topological magnetic textures that hold great promise as nanoscale bits of information in memory and logic devices. Although room-temperature ferromagnetic s…
Observational Searches for Solar g-modes: Some Theoretical Considerations
Pawan Kumar, Eliot Quataert, John N. Bahcall
We argue that the solar g-modes are unlikely to have caused the discrete peaks in the power spectrum of the solar wind flux observed by Thomson et al. (1995). The lower limit to th…
Multi-scale photonic emissivity engineering for relativistic lightsail thermal regulation
John Brewer, Matthew F. Campbell, Pawan Kumar +4
The Breakthrough Starshot Initiative aims to send a gram-scale probe to Proxima Centuri B using a laser-accelerated lightsail traveling at relativistic speeds. Thermal management i…
Implications of electron acceleration for high-energy radiation from gamma-ray bursts
Rodolfo Barniol Duran, Pawan Kumar
In recent work we suggested that photons of energy >100 MeV detected from GRBs by the Fermi Satellite are produced via synchrotron emission in the external forward shock with a wea…
External inverse-Compton emission from jetted tidal disruption events
Wenbin Lu, Pawan Kumar
The recent discoveries of Swift J1644+57 and J2058+05 show that tidal disruption events (TDEs) can launch relativistic jets. Super-Eddington accretion produces a strong radiation f…
A novel paradigm for short gamma-ray bursts with extended X-ray emission
Luciano Rezzolla, Pawan Kumar
The merger of a binary of neutron stars provides natural explanations for many of the features of short gamma-ray bursts (SGRBs), such as the generation of a hot torus orbiting a r…
Hadronic Models for LAT Prompt Emission Observed in Fermi Gamma-Ray Bursts
Patrick Crumley, Pawan Kumar
This paper examines the possibility that hadronic processes produce the >100 MeV photons in the prompt phase of gamma-ray bursts (GRBs) observed by the Fermi-LAT. We calculate anal…
Adaptive Consensus Optimization Method for GANs
Sachin Kumar Danisetty, Santhosh Reddy Mylaram, Pawan Kumar
We propose a second order gradient based method with ADAM and RMSprop for the training of generative adversarial networks. The proposed method is fastest to obtain similar accuracy…
Variabilities in the polar field and solar cycle due to irregular properties of Bipolar Magnetic Regions
Pawan Kumar, Bidya Binay Karak, Anu Sreedevi
Decay and dispersal of the tilted Bipolar Magnetic Regions (BMRs) on the solar surface are observed to produce large-scale poloidal field, which acts as the seed for the toroidal f…
Model-dependent high-energy neutrino flux from Gamma-Ray Bursts
Bing Zhang, Pawan Kumar
The IceCube Collaboration recently reported a stringent upper limit on the high energy neutrino flux from GRBs, which provides a meaningful constraint on the standard internal shoc…
On the radiation mechanism of repeating fast radio bursts
Wenbin Lu, Pawan Kumar
Recent observations show that fast radio bursts (FRBs) are energetic but probably non-catastrophic events occurring at cosmological distances. The properties of their progenitors a…
Simulations of Accretion Powered Supernovae in the Progenitors of Gamma Ray Bursts
Christopher C. Lindner, Milos Milosavljevic, Rongfeng Shen +1
Observational evidence suggests a link between long duration gamma ray bursts (LGRBs) and Type Ic supernovae. Here, we propose a potential mechanism for Type Ic supernovae in LGRB…
Group index matched frequency conversion in lithium niobate on insulator waveguides
Pawan Kumar, Mohammadreza Younesi, Sina Saravi +2
Sources of spectrally engineered photonic states are a key resource in several quantum technologies. Of particular importance are the so-called factorizable biphoton states which p…
Giant magnetocaloric effect in magnetoelectric Eu1-xBaxTiO3
Km Rubi, Pawan Kumar, D. V. Maheswar Repaka +3
We report the magnetic entropy change (Delta Sm) in magnetoelectric Eu1-xBaxTiO3 for x = 0.1- 0.9. We find - delta Sm = 11 (40) J/kg.K in x = 0.1 for a field change of 1 (5) Tesla…
Radiative interaction between the relativistic jet and optically thick envelope in tidal disruption events
Wenbin Lu, Julian Krolik, Patrick Crumley +1
Reverberation observations have uncovered an Fe Kα fluorescence line in the tidal disruption event (TDE) Swift J1644+57 (Kara et al. 2016). The discovery paper used the lag spectr…
The structure of the central disk of NGC 1068: a clumpy disk model
Pawan Kumar
NGC 1068 is one of the best studied Seyfert II galaxies, for which the blackhole mass has been determined from the Doppler velocities of water maser. We show that the standard …
Cyber-Physical System Design Space Exploration for Affordable Precision Agriculture
Pawan Kumar, Hokeun Kim
Precision agriculture promises higher yields and sustainability, but adoption is slowed by the high cost of cyber-physical systems (CPS) and the lack of systematic design methods.…