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Manan Shah

Publications and source records attributed to Manan Shah.

34 records · Page 2Linked to original sources
arXiv2023

Development of High-Quality Polymer/Air-Bragg Micromirror Structures for Nanophotonic Applications

We report the design, nanofabrication, and characterization of high-quality polymer-based micromirror structures employing the 3D two-photon polymerization lithography technique. Compared to conventional microcavity approaches, our innovative concept provides microstructures which allow fast prototyping. Moreover, our polymer-based mirrors are cost effective, environmentally sensitive, as well as compatible with a wide range of wavelengths from NIR to the telecom C-band. We demonstrate polymer/air distributed Bragg reflectors and full microcavity structures with up to 14 mirror pairs with a target wavelength of 1550 nm and a reflectivity close to 99%. Additionally, our 3D printed micromirrors are reproducible, mechanically stable, and enable hybrid nanophotonic devices based on quantum dots, molecules or 2D quantum materials as active medium.

physics.optics↗
arXiv2022

Carbon Emission Prediction on the World Bank Dataset for Canada

The continuous rise in CO2 emission into the environment is one of the most crucial issues facing the whole world. Many countries are making crucial decisions to control their carbon footprints to escape some of their catastrophic outcomes. There has been a lot of research going on to project the amount of carbon emissions in the future, which can help us to develop innovative techniques to deal with it in advance. Machine learning is one of the most advanced and efficient techniques for predicting the amount of carbon emissions from current data. This paper provides the methods for predicting carbon emissions (CO2 emissions) for the next few years. The predictions are based on data from the past 50 years. The dataset, which is used for making the prediction, is collected from World Bank datasets. This dataset contains CO2 emissions (metric tons per capita) of all the countries from 1960 to 2018. Our method consists of using machine learning techniques to take the idea of what carbon emission measures will look like in the next ten years and project them onto the dataset taken from the World Bank's data repository. The purpose of this research is to compare how different machine learning models (Decision Tree, Linear Regression, Random Forest, and Support Vector Machine) perform on a similar dataset and measure the difference between their predictions.

cs.LG↗
arXiv2021

Advancement of Deep Learning in Pneumonia and Covid-19 Classification and Localization: A Qualitative and Quantitative Analysis

Around 450 million people are affected by pneumonia every year which results in 2.5 million deaths. Covid-19 has also affected 181 million people which has lead to 3.92 million casualties. The chances of death in both of these diseases can be significantly reduced if they are diagnosed early. However, the current methods of diagnosing pneumonia (complaints + chest X-ray) and covid-19 (RT-PCR) require the presence of expert radiologists and time, respectively. With the help of Deep Learning models, pneumonia and covid-19 can be detected instantly from Chest X-rays or CT scans. This way, the process of diagnosing Pneumonia/Covid-19 can be made more efficient and widespread. In this paper, we aim to elicit, explain, and evaluate, qualitatively and quantitatively, major advancements in deep learning methods aimed at detecting or localizing community-acquired pneumonia (CAP), viral pneumonia, and covid-19 from images of chest X-rays and CT scans. Being a systematic review, the focus of this paper lies in explaining deep learning model architectures which have either been modified or created from scratch for the task at hand wiwth focus on generalizability. For each model, this paper answers the question of why the model is designed the way it is, the challenges that a particular model overcomes, and the tradeoffs that come with modifying a model to the required specifications. A quantitative analysis of all models described in the paper is also provided to quantify the effectiveness of different models with a similar goal. Some tradeoffs cannot be quantified, and hence they are mentioned explicitly in the qualitative analysis, which is done throughout the paper. By compiling and analyzing a large quantum of research details in one place with all the datasets, model architectures, and results, we aim to provide a one-stop solution to beginners and current researchers interested in this field.

eess.IV↗
arXiv2021

Radiative Pattern of Intralayer and Interlayer Excitons in Two-Dimensional WS2/WSe2 Heterostructure

Two-dimensional (2D) heterostructures (HS) formed by transition-metal dichalcogenide (TMDC) monolayers offer a unique platform for the study of intralayer and interlayer excitons as well as moiré-pattern-induced features. Particularly, the dipolar charge-transfer exciton comprising an electron and a hole, which are confined to separate layers of 2D semiconductors and Coulomb-bound across the heterojunction interface, has drawn considerable attention in the research community. On the one hand, it bears significance for optoelectronic devices, e.g. in terms of charge carrier extraction from photovoltaic devices. On the other hand, its spatially indirect nature and correspondingly high longevity among excitons as well as its out-of-plane dipole orientation render it attractive for excitonic Bose-Einstein condensation studies, which address collective coherence effects, and for photonic integration schemes with TMDCs. Here, we demonstrate the interlayer excitons' out-of-plane dipole orientation through angle-resolved spectroscopy of the HS photoluminescence at cryogenic temperatures, employing a tungsten-based TMDC HS. Within the measurable light cone, the directly-obtained radiation profile of this species clearly resembles that of an in-plane emitter which deviates from that of the intralayer bright excitons as well as the other excitonic HS features recently attributed to artificial superlattices formed by moiré patterns.

cond-mat.mes-hall↗
arXiv2020

SParSH-AMG: A library for hybrid CPU-GPU algebraic multigrid and preconditioned iterative methods

Hybrid CPU-GPU algorithms for Algebraic Multigrid methods (AMG) to efficiently utilize both CPU and GPU resources are presented. In particular, hybrid AMG framework focusing on minimal utilization of GPU memory with performance on par with GPU-only implementations is developed. The hybrid AMG framework can be tuned to operate at a significantly lower GPU-memory, consequently, enables to solve large algebraic systems. Combining the hybrid AMG framework as a preconditioner with Krylov Subspace solvers like Conjugate Gradient, BiCG methods provides a solver stack to solve a large class of problems. The performance of the proposed hybrid AMG framework is analysed for an array of matrices with different properties and size. Further, the performance of CPU-GPU algorithms are compared with the GPU-only implementations to illustrate the significantly lower memory requirements.

cs.MS↗
arXiv2020

Masses of tetraquark states in the hidden charm sector above $D-D^*$ threshold

In the diquark-diantiquark composition, we study the masses of hidden charm tetraquark systems ($cq\bar{c}\bar{q}$, $cs\bar{c}\bar{s}$ and $cs\bar{c}\bar{q}$) using a linear confinement potential. In this study, we have factorized the four body system into three subsequent two body systems. To remove degeneracy in the S and P wave masses of mesons and tetraquark states, the spin-spin, spin orbit and tensor components of the confined one gluon exchange interactions are employed. In this attempt, we have been able to assign the $ψ(4230)$ as pure $cq\bar{c}\bar{q}$ tetraquark state. $ψ(4360)$ and $ψ(4390)$ as pure $cs\bar{c}\bar{q}$ tetraquark states. According to our analysis $ψ(4260)$ is an admixture of $^1P_1$ and $^5P_1$ $cq\bar{c}\bar{q}$ tetraquark state. Additionally, we have been able to predict the radiative decay width $Γ_{(ψ\rightarrow J/ψγ)}$, leptonic decay width $Γ_{e^+e^-}$ and hadronic decays of $1^{--}$ tetraquark stat

hep-ph↗
arXiv2019

Spectroscopy and decay properties of bottomonium using instanton induced potential from QCD vacuum

Ground state and radial excitation mass spectra of bottomonium states are computed using the Instanton Induced $q \bar{q}$ Potential obtained from Instanton Liquid Model for QCD vacuum. The Schrodinger equation is solved for two body problem using variational method. Hyperfine interactions are incorporated to remove the degeneracy between spin singlet and spin triplet states of $S$ wave masses. Spin-orbit and tensor interactions through one gluon exchange has been added to the spin average masses of P and D wave states. The vector decay constants and pseudoscalar decay constants are also estimated using the Van Royan Weiskopff formula within non-relativistic limit. The di-leptonic, di-gamma, di-gluon decays of the bottomonium states are predicted without and with QCD corrections up to the lowest order using numerical values of the wave function at origin. Tri-gluon decays of respective $S$, $P$ and $D$ states are also studied. Other annihilation decay channels of bottomonium states into $γgg$ , $γγγ$ , $q\bar{q} + g $ are also computed. The radiative transitions of first order like electric dipole transitions (E1) and magnetic dipole transitions (M1) are estimated. Our estimations of the mass spectra and decay properties for bottomonium found to be in excellent agreement with the average experimental values reported by particle data group.

hep-ph↗
arXiv2018

Status of quarkonia - like negative and positive parity states in a relativistic confinement scheme

Properties of quarkonia - like states in the charm and bottom sector have been studied in the frame work of relativistic Dirac formalism with a linear confinement potential. We have computed the mass spectroscopy and decay properties (vector decay constant and leptonic decay width) of several quarkonia - like states. Present study is also intended to identify some of the unexplained states as mixed P-wave and mixed S-D wave states of Charmonia and Bottomonia. The results indicate that the X(4140) state can be an admixture of two P states of charmonium. And the charmonium like states X(4630) and X(4660) are the admixed state of S - D waves. Similarly, the $X(10610)$ state recently reported by Belle II can be a mixed P - states of bottomonium. In the relativistic framework we have computed vector decay constant and the leptonic decay width for S wave charmonium and bottomonium. The leptonic decay width for the $J^{PC} = 1^{--}$ mixed states are also predicted. Further, both the masses and the leptonic decay width are considered for the identification of the quarkonia-like states.

hep-ph↗
arXiv2016

Deep Learning Assessment of Tumor Proliferation in Breast Cancer Histological Images

Current analysis of tumor proliferation, the most salient prognostic biomarker for invasive breast cancer, is limited to subjective mitosis counting by pathologists in localized regions of tissue images. This study presents the first data-driven integrative approach to characterize the severity of tumor growth and spread on a categorical and molecular level, utilizing multiple biologically salient deep learning classifiers to develop a comprehensive prognostic model. Our approach achieves pathologist-level performance on three-class categorical tumor severity prediction. It additionally pioneers prediction of molecular expression data from a tissue image, obtaining a Spearman's rank correlation coefficient of 0.60 with ex vivo mean calculated RNA expression. Furthermore, our framework is applied to identify over two hundred unprecedented biomarkers critical to the accurate assessment of tumor proliferation, validating our proposed integrative pipeline as the first to holistically and objectively analyze histopathological images.

cs.CV↗
arXiv2015

Mass spectra and decay properties of $D$ Meson in a relativistic Dirac formalism

The mass spectra of $D$ meson states are calculated in the framework of a relativistic independent quark model. For the present study, we have used the martin like potential for the quark confinement. Our predicted states in S-wave, $2\ ^3S_1$ (2605.86 MeV) and $2\ ^1S_0$ (2521.72 MeV) are in very good agreement with experimental result of $2608\pm{2.4}\pm{2.5}$ MeV and $2539.4\pm{4.5}\pm{6.8}$ MeV respectively reported by BABAR Collaboration. The calculated P-wave $D$ meson states, $1^3P_2$ (2468.22 MeV), $1^3P_1$ (2404.94 MeV), $1^3P_0$ (2315.24 MeV) and $1^1P_1$ (2367.94 MeV) are in close agreement with experimental average (Particle Data Group) values of $2462.6 \pm 0.7 $ MeV, $2427 \pm 26 \pm 25$ MeV, $2318 \pm 29 $ MeV and $2421.3 \pm 0.6 $ MeV respectively. The pseudoscalar decay constant ($f_P$= 202.57 MeV) of $D$ meson obtained using this relativistic formalism is in very good agreement with the experiment as well as with the lattice and other available theoretical predictions. The Cabibbo favoured hadronic decay branching ratios, BR$(D^0\rightarrow K^- π^+)$ as $3.835 \%$ and BR $(D^0\rightarrow K^+ π^-)$ as $1.069 \times 10^{-4} $ are also in very good agreement with the respective experimental values of $ 3.91 \pm 0.08\%$ and $(1.48\pm 0.07) \times 10^{-4}$ reported by CLEO Collaboration. Our predicted results in leptonic decay widths of $D$ meson are also in better accord with experiment as well as other theoretical results. The mixing parameters of $D^0 - \bar{D}^0$ oscillation, $x_q$ (5.14 $\times 10^{-3}$), $y_q$ (6.02 $\times 10^{-3}$) and $R_M$ (3.13 $\times 10^{-5}$) are in very good agreement with BaBar and Belle Collaboration results.

hep-ph↗
arXiv2014

Mass spectra of four quark states in hidden charm sector

Masses of the low lying four quark states in the hidden charm sector ($cq\bar c \bar q; q\in u,d$) are calculated within the framework of a non-relativistic quark model. The four body system is considered as two two-body systems such as diquark-antidiquark ($Qq-\bar Q \bar q$) and quark antiquark-quark antiquark ($Q\bar q -\bar Qq$) molecular-like four quark states. Here, Cornell type potential has been used for describing the two body interactions among $Q-q$, $\bar Q-\bar q$, $Q-\bar q$, $Qq-\bar Q \bar q$ and $Q\bar q-\bar Qq$, with appropriate string tensions. Our present analysis suggests the following exotic states, $X(3823)$, $Z_c(3900)$, $X(3915)$, $Z_c(4025)$, $ψ(4040)$, $Z_1(4050)$ and $X(4160)$ as $Q\bar q-\bar Qq$ molecular-like four quark states while $Z_c(3885)$, $X(3940)$ and $Y(4140)$ as the diquark-antidiquark four quark states. We have been able to assign the $J^{PC}$ values for many of the recently observed exotic states according to their structure. Apart from this, we have identified the charged state $Z(4430)$ recently confirmed by LHCb as the first radial excitation of $Zc(3885)$ with G=+1 and $Y(4360)$ state as the first radial excitation of $Y(4008)$ with $G=-1$ and the state $ψ(4415)$ as the first radial excitation of the $ψ(4040)$ state.

hep-ph↗
arXiv2014

Mass spectra and decay properties of $D_s$ Meson in a relativistic Dirac formalism

The mass spectra of $D_s$ meson is obtained in the framework of relativistic independent quark model using Martin like potential for the quark confinement. The predicted excited states are in good agreement with the experimental results as well as with the lattice and other theoretical predictions. The spectroscopic parameters are employed further to compute the decay constant, electromagnetic transition and leptonic decay widths. The present result for its decay constant, $f_P$ (252.82 MeV) is in excellent agreement with the value 252.6 $\pm$ 11.1 MeV reported by CLEO-c and the predicted branching ratios for $(D_s \rightarrow τ\barν_τ, μ\barν_μ)$ ($5.706 \times 10^{-2}, 5.812 \times 10^{-3}$) are in close agreement with the PDG values ($ (5.43 \pm 0.31)\times 10^{-2}, (5.90 \pm 0.33)\times 10^{-3} $) respectively.

hep-ph↗
arXiv2013

Status of $ψ$ (3686), $ψ$ (4040), $ψ$ (4160), Y (4260), $ψ$ (4415) and X (4630) charmonia like states

We examine the status of charmonia like states by looking into the behaviour of the energy level differences and regularity in the behaviour of the leptonic decay widths of the excited charmonia states. The spectroscopic states are studied using a phenomenological Martin-like confinement potential and their radial wave functions are employed to compute the di-leptonic decay widths. Their deviations from the expected behaviour provide a clue to consider them as admixtures of the nearby S and D states. The present analysis strongly favour \$$\backslash$psi \$ (3686) as admixture of $c \bar{c}$ (2S) and $c \bar{c}$g (4.1 GeV) hybrid, \$$\backslash$psi \$ (4040) and \$$\backslash$psi \$ (4160) as admixture states of charmonia (3S, 3D) states with mixing angle \$$\backslash$theta \$ = 11$^\circ$ and 45$^\circ$ respectively. We identify Y (4260) as a pure $c \bar{c}$ (4S) state whose leptonic decay is predicted as 0.65 keV. While X(4630) is closer to the $c \bar{c}$ (6S) state. The status of \$$\backslash$psi \$ (4415) is still not clear as it does not fit to be pure or admixture state.

hep-ph↗
arXiv2013

Spectroscopy of di-meson bound states in charm and beauty sector

Using the Woods Saxon plus Coulomb type of interaction between two hadron molecules, we have calculated the binding energies and masses of the tetraquark states such as $D\bar{D}$, $D\bar{D}^*$, $D^*\bar{D}^*$, $D^+\bar{D}^*$ in the charm sector and $B\bar{B}$, $B^*\bar{B}^*$, $B\bar{B}^*$ in the bottom sector.

hep-ph↗
arXiv2012

Leptonic and Digamma decay Properties of S-wave quarkonia states

Based on Martin like potential, the S-wave masses of quarkonia have been reviewed. Resultant wave functions at zero inter quark separation are employed to compute the hyperfine splitting of the nS states and the leptonic and digamma decay widths of $n{^3S_1}$ and $n{^1S_0}$ states of quarkonia respectively. Analysis on the level differences of S-wave excited states of quantum mechanical bound systems show a systematic behaviour as n-increases. In view of such systematic behaviour expected for quarkonia, we observe that Y(4263) and X(4630) $1^{--}$ states are closer to the 4S and 6S states while $ψ(4415)$ and Z(4430) are closer to the 5S state of $c\bar{c}$ systems. Similarly we find $Υ(10865)$ is not fit to be the 5S state of $b\bar{b}$ system. while $Y_b (10880)$ observed by Belle or (10996) observed by Babar fit to be the 6S state of bottonia. Our predicted leptonic width, 0.242 keV of $Υ(10579, 4S)$ is in good agreement with the experimental value of 0.272 $\pm$ 0.029 keV. We predict the leptonic widths of the pure 5S and 6S states of upsilon states as 0.191 keV and 0.157 keV respectively. In the case of charmonia, we predict the leptonic widths of the 4S, 5S and 6S states as 0.654 keV, 0.489 keV and 0.387 keV respectively.

hep-ph↗