arXiv subjects

Anil Kumar

Publications and source records attributed to Anil Kumar.

At least 91 records · Page 5Linked to original sources

arXiv2021

Structure of $^{46,47}$Ca from the $β^-$ decay of $^{46,47}$K in the framework of nuclear shell model

In the present work, we report a comprehensive theoretical study of the $\log ft$ values for the allowed and forbidden $β^-$ decay transitions of $^{46}$K and $^{47}$K corresponding to recently available experimental data from the GRIFFIN spectrometer at TRIUMF-ISAC [Phys. Rev. C {\bf 100}, 054327 (2019); Phys. Rev. C {\bf 102}, 054314 (2020)]. We perform the nuclear shell-model calculation in $sdpf$-valence space, with the SDPF-MU interaction, to calculate low-lying energy spectra of $^{46,47}$K and $^{46,47}$Ca. For further investigation, we also calculate spectroscopic properties of $^{46,47}$K, $^{46,47}$Ca and compare the results with the experimental data. We suggest spin-parity of several levels, which were previously tentative, in both the calcium isotopes. Based on the energy and $\log ft$ values, we conclude that the state at 3.984 MeV in $^{46}$Ca could be either $3^{-}$ or $2^{+}$ and a state at 4.432 MeV might be $3^{-}$. The spin-parity of the states at 2.875, 3.951 and 4.453 MeV are predicted to be $1/2^-$, $3/2^-$ and $1/2^-$ or $1/2^+$, respectively, in $^{47}$Ca. We also give the confirmation to spin-parity of 2.850, 3.889 and 4.606 MeV states for $^{47}$Ca. Our results of level schemes of $^{46,47}$K are in a reasonable agreement with the experimental data, while the agreement of calculated $\log ft$ values for the $β^-$ decay with the experimental data is limited.

nucl-th↗

arXiv2021

A New Approach to Probe Non-Standard Interactions in Atmospheric Neutrino Experiments

We propose a new approach to explore the neutral-current non-standard neutrino interactions (NSI) in atmospheric neutrino experiments using oscillation dips and valleys in reconstructed muon observables, at a detector like ICAL that can identify the muon charge. We focus on the flavor-changing NSI parameter $\varepsilon_{μτ}$, which has the maximum impact on the muon survival probability in these experiments. We show that non-zero $\varepsilon_{μτ}$ shifts the oscillation dip locations in $L/E$ distributions of the up/down event ratios of reconstructed $μ^-$ and $μ^+$ in opposite directions. We introduce a new variable $Δd$ representing the difference of dip locations in $μ^-$ and $μ^+$, which is sensitive to the magnitude as well as the sign of $\varepsilon_{μτ}$, and is independent of the value of $Δm^2_{32}$. We further note that the oscillation valley in the ($E$, $\cos θ$) plane of the reconstructed muon observables bends in the presence of NSI, its curvature having opposite signs for $μ^-$ and $μ^+$. We demonstrate the identification of NSI with this curvature, which is feasible for detectors like ICAL having excellent muon energy and direction resolutions. We illustrate how the measurement of contrast in the curvatures of valleys in $μ^-$ and $μ^+$ can be used to estimate $\varepsilon_{μτ}$. Using these proposed oscillation dip and valley measurements, the achievable precision on $|\varepsilon_{μτ}|$ at 90% C.L. is about 2% with 500 kt$\cdot$yr exposure. The effects of statistical fluctuations, systematic errors, and uncertainties in oscillation parameters have been incorporated using multiple sets of simulated data. Our method would provide a direct and robust measurement of $\varepsilon_{μτ}$ in the multi-GeV energy range.

hep-ph↗

arXiv2021

Probing NSI in Atmospheric Neutrino Experiments using Oscillation Dip and Valley

We propose a new approach to probe neutral-current non-standard neutrino interaction parameter $\varepsilon_{μτ}$ using the oscillation dip and oscillation valley. Using the simulated ratio of upward-going and downward-going reconstructed muon events at the upcoming ICAL detector, we demonstrate that the presence of non-zero $\varepsilon_{μτ}$ would result in the shift in the dip location as well as the bending of the oscillation valley. Thanks to the charge identification capability of ICAL, the opposite shifts in the locations of oscillation dips as well as the contrast in the curvatures of oscillation valleys for $μ^-$ and $μ^+$ is used to constrain $|\varepsilon_{μτ}|$ at 90% C.L. to about 2% using 500 kt$\cdot$yr exposure. Our procedure incorporates statistical fluctuations, uncertainties in oscillation parameters, and systematic errors.

hep-ph↗

arXiv2021

From oscillation dip to oscillation valley in atmospheric neutrino experiments

Atmospheric neutrino experiments can show the "oscillation dip" feature in data, due to their sensitivity over a large $L/E$ range. In experiments that can distinguish between neutrinos and antineutrinos, like INO, oscillation dips can be observed in both these channels separately. We present the dip-identification algorithm employing a data-driven approach -- one that uses the asymmetry in the upward-going and downward-going events, binned in the reconstructed $L/E$ of muons -- to demonstrate the dip, which would confirm the oscillation hypothesis. We further propose, for the first time, the identification of an "oscillation valley" in the reconstructed ($E_μ$,$\,\cosθ_μ$) plane, feasible for detectors like ICAL having excellent muon energy and direction resolutions. We illustrate how this two-dimensional valley would offer a clear visual representation and test of the $L/E$ dependence, the alignment of the valley quantifying the atmospheric mass-squared difference. Owing to the charge identification capability of the ICAL detector at INO, we always present our results using $μ^{-}$ and $μ^{+}$ events separately. Taking into account the statistical fluctuations and systematic errors, and varying oscillation parameters over their currently allowed ranges, we estimate the precision to which atmospheric neutrino oscillation parameters would be determined with the 10-year simulated data at ICAL using our procedure.

hep-ph↗

arXiv2021

Material and Process Tolerant High Efficiency Solar Cells with Dynamic Recovery of Performance

Low cost, highly efficient, and stable solar cells demand low temperature processing, less stringent criteria on materials, and possibility of dynamic recovery from long term degradation: a combination of features unachievable from the perspectives of current cSi technology. To this end, here we propose a novel solar cell architecture with an additional control gate. Our simulation results indicate that the proposed device can achieve excellent efficiency even if the back-surface passivation is sub-optimal; thus allowing exploration of a wide variety of materials and low temperature fabrication processes. Importantly, such solar cells can dynamically offset efficiency loss due to elevated temperature and interface degradation associated with long term field operation and hence could be of broad interest to the PV community.

physics.app-ph↗

arXiv2021

Explosive synchronization in interlayer phase-shifted Kuramoto oscillators on multiplex networks

We show that an introduction of a phase parameter ($α$), with $0 \le α\le π/2$, in the interlayer coupling terms of multiplex networks of Kuramoto oscillators can induce explosive synchronization (ES) in the multiplexed layers. Along with the α values, the hysteresis width is determined by the interlayer coupling strength and the frequency mismatch between the mirror (inter-connected) nodes. A mean-field analysis is performed to support the numerical results. Similar to the earlier works, we find that the suppression of synchronization is accountable for the origin of ES. The robustness of ES against changes in the network topology and frequency distribution is tested. Finally, taking a suggestion from the synchronized state of the multiplex networks, we extend the results to the classical concept of the single-layer networks in which some specific links are assigned a phase-shifted coupling. Different methods have been introduced in the past years to incite ES in coupled oscillators; our results indicate that a phase-shifted coupling can also be one such method to achieve ES.

nlin.AO↗

arXiv2020

Configurational Entropy of Optical Bright Similariton in Tapered Graded-Index Waveguide

Configurational entropy (CE) consists of a family of entropic measures of information used to describe the shape complexity of spatially-localized functions with respect to a set of parameters. We obtain the Differential Configurational Entropy (DCE) for similariton waves traveling in tapered graded-index optical waveguides modeled by a generalized nonlinear Schrödinger equation. It is found that for similariton's widths lying within a certain range, DCE attains minimum saturation values as the nonlinear wave evolves along the effective propagation variable $ζ(t)$. In particular, saturation is achieved earlier for lower values of the width, which we show correspond to global minima of the DCE. Such low entropic values lead to minimum dispersion of momentum modes as the similariton waves propagate along tapered graded-index waveguides, and should be of importance in guiding their design.

nlin.PS↗

arXiv2020

Surface tensiometry of phase separated protein and polymer droplets by the sessile drop method

Phase separated macromolecules play essential roles in many biological and synthetic systems. Physical characterization of these systems can be challenging because of limited sample volumes, particularly for phase-separated proteins. Here, we demonstrate that a classic method for measuring the surface tension of liquid droplets, based on the analysis of the shape of a sessile droplet, can be effectively scaled down for this application. The connection between droplet shape and surface tension relies on the density difference between the droplet and its surroundings. This can be determined with small sample volumes in the same setup by measuring the droplet sedimentation velocity. An interactive MATLAB script for extracting the capillary length from a droplet image is included in the ESI.

cond-mat.soft↗

arXiv2020

Second-forbidden nonunique $β^-$ decays of $^{24}$Na and $^{36}$Cl assessed by the nuclear shell model

We have performed a systematic study of the log$ft$ values, shape factors and electron spectra for the second-forbidden nonunique $β^-$ decays of $^{24}$Na$(4^+) \rightarrow ^{24}$Mg$(2^+)$ and $^{36}$Cl$(2^+) \rightarrow ^{36}$Ar$(0^+)$ transitions under the framework of the nuclear shell model. We have performed the shell model calculations in the $sd$ model space, using more recent microscopic effective interactions such as Daejeon16, chiral N3LO, and JISP16. These interactions are derived from the no-core shell model wave functions using Okubo-Lee-Suzuki transformation.For comparison, we have also shown the results obtain from the phenomenological USDB interaction. To test the predictive power of these interactions first we have computed low-lying energy spectra of parent and daughter nuclei involved in these transitions. The computed results for energy spectra, nuclear matrix elements, log$ft$ values, shape factors, electron spectra and decomposition of the integrated shape factor are reported and compare with the available experimental data.

nucl-th↗

arXiv2020

Gamow-Teller transition strengths for selected ${fp}$ shell nuclei

We have reported a systematic shell model description of the experimental Gamow-Teller transition strength for $^{44}$Sc $\rightarrow$ $^{44}$Ca, $^{45}$Ti $\rightarrow$ $^{45}$Sc, $^{48}$Ti $\rightarrow$ $^{48}$V, $^{66}$Co $\rightarrow$ $^{66}$Ni, and $^{66}$Fe $\rightarrow$ $^{66}$Co transitions using KB3G and GXPF1A interactions for $fp$ model space. In order to see the importance of higher orbital for $^{66}$Co $\rightarrow$ $^{66}$Ni and $^{66}$Fe $\rightarrow$ $^{66}$Co transitions, we have reported the shell model results with $fpg_{9/2}$ space using GXPF1Br+$V_{MU}$ interaction. We have obtained the qualitative agreement for the individual transitions, while the calculated summed transition strengths closely reproduce the observed ones.

nucl-th↗

arXiv2020

Shell model results for nuclear $β^-$-decay properties of $sd$ shell nuclei

We evaluate the allowed $β^-$-decay properties of nuclei with $Z = 8 - 15$ systematically under the framework of the nuclear shell model with the use of the valence space Hamiltonians derived from modern $ab~intio$ methods, such as in-medium similarity renormalization group and coupled-cluster theory. For comparison we also show results obtained with fitted interaction derived from the chiral effective field theory and phenomenological USDB interaction. We have performed calculations for O $\rightarrow$ F, F $\rightarrow$ Ne, Ne $\rightarrow$ Na, Na $\rightarrow$ Mg, Mg $\rightarrow$ Al, Al $\rightarrow$ Si, Si $\rightarrow$ P and P $\rightarrow$ S transitions. Theoretical results of $B(GT)$, log$ft$ values and half-lives, are discussed and compared with the available experimental data.

nucl-th↗

arXiv2019

Inter-layer adaptation induced explosive synchronization in multiplex networks

It is known that intra-layer adaptive coupling among connected oscillators instigates explosive synchronization (ES) in multilayer networks. Taking an altogether different cue in the present work, we consider inter-layer adaptive coupling in a multiplex network of phase oscillators and show that the scheme gives rise to ES with an associated hysteresis irrespective of the network architecture of individual layers. The hysteresis is shaped by the inter-layer coupling strength and the frequency mismatch between the mirror nodes. We provide rigorous mean-field analytical treatment for the measure of global coherence and manifest they are in a good match with respective numerical assessments. Moreover, the analytical predictions provide a complete insight into how adaptive multiplexing suppresses the formation of a giant cluster, eventually giving birth to ES. The study will help in spotlighting the role of multiplexing in the emergence of ES in real-world systems represented by multilayer architecture. Particularly, it is relevant to those systems which have limitations towards change in intra-layer coupling strength.

nlin.AO↗

arXiv2019

Deep 3D Convolutional Neural Network for Automated Lung Cancer Diagnosis

Computer Aided Diagnosis has emerged as an indispensible technique for validating the opinion of radiologists in CT interpretation. This paper presents a deep 3D Convolutional Neural Network (CNN) architecture for automated CT scan-based lung cancer detection system. It utilizes three dimensional spatial information to learn highly discriminative 3 dimensional features instead of 2D features like texture or geometric shape whick need to be generated manually. The proposed deep learning method automatically extracts the 3D features on the basis of spatio-temporal statistics.The developed model is end-to-end and is able to predict malignancy of each voxel for given input scan. Simulation results demonstrate the effectiveness of proposed 3D CNN network for classification of lung nodule in-spite of limited computational capabilities.

eess.IV↗

arXiv2018

Understanding Psycholinguistic Behavior of predominant drunk texters in Social Media

In the last decade, social media has evolved as one of the leading platform to create, share, or exchange information; it is commonly used as a way for individuals to maintain social connections. In this online digital world, people use to post texts or pictures to express their views socially and create user-user engagement through discussions and conversations. Thus, social media has established itself to bear signals relating to human behavior. One can easily design user characteristic network by scraping through someone's social media profiles. In this paper, we investigate the potential of social media in characterizing and understanding predominant drunk texters from the perspective of their social, psychological and linguistic behavior as evident from the content generated by them. Our research aims to analyze the behavior of drunk texters on social media and to contrast this with non-drunk texters. We use Twitter social media to obtain the set of drunk texters and non-drunk texters and show that we can classify users into these two respective sets using various psycholinguistic features with an overall average accuracy of 96.78% with very high precision and recall. Note that such an automatic classification can have far-reaching impact - (i) on health research related to addiction prevention and control, and (ii) in eliminating abusive and vulgar contents from Twitter, borne by the tweets of drunk texters.

cs.CY↗

arXiv2018

Experimental Demonstration of Non-Destructive Discrimination of Arbitrary Set of Orthogonal Quantum States Using 5-qubit IBM Quantum Computer on Cloud

A protocol for non-destructive descrimination of arbitrary set of orthogonal quantum states was proposed by V. S. Manu et al., using an algorithm based on quantum phase estimation. IBM Corporation has released a superconductivity based 5-qubit (5-qubit transmon bowtie chip 3 and IBM 5-qubit real processor) quantum computer named Quantum Experience and placed it on cloud. In this paper we take advantage of the online availability of those real quantum processors(ibmqx2 amd ibmqx4) and carry out the above protocol that has experimentally demonstrated earlier using NMR quantum processor. Here, we set up experiments for arbitrary one-qubit and two-qubit orthogonal quantum states. The experiment confirmed that the arbitrary orthogonal quantum states can be discriminate in a nondestructive manner with a high fidelity. We compare the outcomes of those experiments which are done by ibmqx2 and ibmqx4 processors. Here, we also show the state tomography for the single qubit experiments.

quant-ph↗

arXiv2017

Experimental Realization of Secure Multiparty Quantum Summation Using Five-Qubit IBM Quantum Computer on Cloud

A scheme for secure multiparty quantum summation was proposed by Run-hau Shi et al.,(SCIENTIFIC REPORTS, 6:19655, DOI:10.1038/srep19655). IBM Corporation has released a superconductivity based 5-qubit quantum computer named "Quantum Experience" and placed it on "cloud". In this paper we take advantage of the online availability of this real quantum processor(ibmqx2) and carry out the above protocol that has never been experimentally demonstrated earlier. Here, we set up experiments for secure quantum summation of one-qubit secret states . Besides, we propose a protocol for square and cubic summation and also simulate the proposed protocol for both cases. Experimental implementation of secure multiparty quantum summation protocol for two or more qubit secret state and the proposed protocol for square(and cubic) summation are not possible using the available 5-qubit quantum processor(ibmqx2). IBM has recently placed a 16-qubit quantum processor(ibmqx3) on the cloud but it is still not accessible for all users. We describe a simulation for two and three qubit secret state and proposed protocol for square(and cubic) summation using a simulator(Custom Topology) which is provided by IBM Corporation.

quant-ph↗

arXiv2016

Hybrid scheme for factorization: Factoring 551 using a 3-qubit NMR quantum adiabatic processor

Quantum processors are potentially superior to their classical counterparts for many computational tasks including factorization. Circuit methods as well as adiabatic methods have already been proposed and implemented for finding the factors of a given composite number. The main challenge in scaling it to larger numbers is the unavailability of large number of qubits. Here we propose a hybrid scheme that involves both classical and quantum computation, which reduces the number of qubits required for factorization. The classical part involves setting up and partially simplifying a set of bit-wise factoring equations and the quantum part involves solving these coupled equations using a quantum adiabatic process. We demonstrate the hybrid scheme by factoring 551 using a three qubit NMR quantum register.

quant-ph↗

arXiv2016

Birth and Death of Chimera: Interplay of Delay and Multiplexing

The chimera state with co-existing coherent-incoherent dynamics has recently attracted a lot of attention due to its wide applicability. We investigate non-locally coupled identical chaotic maps with delayed interactions in the multiplex network framework and find that an interplay of delay and multiplexing brings about an enhanced or suppressed appearance of chimera state depending on the distribution as well as the parity of delay values in the layers. Additionally, we report a layer chimera state with an existence of one layer displaying coherent and another layer demonstrating incoherent dynamical evolution. The rich variety of dynamical behavior demonstrated here can be used to gain further insight into the real-world networks which inherently possess such multi-layer architecture with delayed interactions.

nlin.CD↗