130,864 results on '"Mondal, A."'
Search Results
2. Spin-controlled Electron transport in Chiral Molecular Assemblies for Various Applications
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Gupta, Ritu, Balo, Anujit, Garg, Rabia, Mondal, Amit Kumar, Ghosh, Koyel Banerjee, and Mondal, Prakash Chandra
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Condensed Matter - Materials Science - Abstract
The chirality-induced spin selectivity (CISS) effect has garnered significant interest in the field of molecular spintronics due to its potential for creating spin-polarized electrons without the need for a magnet. Recent studies devoted to CISS effects in various chiral materials demonstrate exciting prospects for spintronics, chiral recognition, and quantum information applications. Several experimental studies have confirmed the applicability of chiral molecules towards spin-filtering properties, influencing spin-polarized electron transport, and photoemission. Researchers aim to predict CISS phenomena and apply this concept to practical applications by compiling experimental results and enhancing understanding of the CISS effect. To expand the possibilities of spin manipulation and create new opportunities for spin-based technologies, researchers are diligently exploring different chiral organic and inorganic materials for probing the CISS effect. This ongoing research holds promise for developing novel spin-based technologies and advancing the understanding of the intricate relationship between chirality and electron spin. This review showcases the remarkable CISS effect and its impact on spintronics, as well as its relevance in various other scientific areas., Comment: 29 pages, 20 figures
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- 2024
3. Radio Lines from accreting Axion Stars
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Maseizik, Dennis, Mondal, Sagnik, Seong, Hyeonseok, and Sigl, Günter
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High Energy Physics - Phenomenology ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Axion-like particles, which we call axions, can compose the missing dark matter and may form substructures such as miniclusters and axion stars. We obtain the mass distributions of axion stars derived from their host miniclusters in our galaxy and find a significant number of axion stars reaching the decay mass, the critical mass set by the axion-photon coupling. Axion stars that have reached the decay mass can accrete surrounding axions either via or directly from their host miniclusters, subsequently converting them into radio photons through parametric resonance. We demonstrate that this accretion provides observable signals by proposing two scenarios: 1) external accretion of background dark matter occurring via miniclusters, and 2) internal accretion of isolated systems occurring directly from the minicluster onto its core. The emitted radio photons are nearly monochromatic with energies around the half of the axion mass. The radio-line signal emanating from such axion stars provides a distinctive opportunity searching for axions, overcoming the widespread radio backgrounds. We estimate the expected radio-line flux density to constrain the axion-photon coupling $g_{a\gamma\gamma}$ at each axion mass and find that the resultant line flux density is strong enough to be observed in radio telescopes such as LOFAR, FAST, ALMA, and upcoming SKA. We can constrain the axion-photon coupling down to $g_{a\gamma\gamma} \simeq 10^{-12} - 10^{-11}\,{\rm GeV}^{-1}$, reaching even $10^{-13}\,{\rm GeV}^{-1}$ depending on the accretion models of axion stars, over an axion mass range of $m_a\simeq 10^{-7} - 10^{-2}\,{\rm eV}$. From a different perspective, this radio-line signal could be a strong hint of an axion at the corresponding mass and also of axion stars within our galaxy., Comment: 34 pages, 7 figures, 2 tables
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- 2024
4. On the family discrimination in 331-model
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Huitu, Katri, Koivunen, Niko, Kärkkäinen, Timo, and Mondal, Subhadeep
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High Energy Physics - Phenomenology - Abstract
In the so-called 331-models the gauge anomalies cancel only if there are three generations of fermions. This requires one of the quark generations to be in a different representation than the other two. But which generation is treated differently? In this work we study how the choice of differently treated generation effects the quark flavour structure and how the discriminated generation can be deduced from experiments. We study a general model based on $\beta=-1/\sqrt{3}$, which contains exotic quarks with same electric charges as SM quarks. We take fully into account the effects from exotic quark mixing with the SM quarks, which is often omitted in literature. We will also pay particular attention to $125$ GeV Higgs, and show analytically why its flavour violating couplings between SM quarks are suppressed., Comment: 36 pages, 2 figures
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- 2024
5. Role of material-dependent properties in THz field-derivative-torque-induced nonlinear magnetization dynamics
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Dutta, Arpita, Mukherjee, Pratyay, Sarangi, Swosti P., Bhattacharjee, Somasree, Pal, Shovon, and Mondal, Ritwik
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Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
The traditional Landau-Lifshitz-Gilbert (LLG) equation has often delineated the linear and nonlinear magnetization dynamics, even at ultrashort timescales e.g., femtoseconds. In contrast, several other non-relativistic and relativistic spin torques have been reported as an extension of the LLG spin dynamics. Here, we explore the contribution of the relativistic field-derivative torque (FDT) in the nonlinear THz magnetization dynamics response applied to ferrimagnets with high Gilbert damping and exchange magnon frequency. Our findings suggest that the FDT plays a significant role in magnetization dynamics in both linear and nonlinear regimes, bridging the gap between the traditional LLG spin dynamics and experimental observations. We find that the coherent THz magnon excitation amplitude is enhanced with the field-derivative torque. Furthermore, a phase shift in the magnon oscillation is induced by the FDT term. This phase shift is almost 90 for the antiferromagnet, while it is almost zero for the ferrimagnet under our investigation. Analyzing the dual THz excitation and their FDT, we find that the nonlinear signals can not be distinctly observed without the FDT terms. However, the inclusion of the FDT terms produces distinct nonlinear signals which matches extremely well with the previously reported experimental results., Comment: 6 figures
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- 2024
6. Distinguishing between topological Majorana and trivial zero modes via transport and shot noise study in an altermagnet heterostructure
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Mondal, Debashish, Pal, Amartya, Saha, Arijit, and Nag, Tanay
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Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Superconductivity - Abstract
We theoretically investigate the transport and shot noise properties of a one-dimensional semiconducting nanowire with Rashba spin-orbit coupling~(SOC) placed in closed proximity to a bulk $s$-wave superconductor and an altermagnet with $d$-wave symmetry. Such heterostructure with vanishing net magnetization manifests itself as an alternative route to anchor Majorana zero modes~(MZMs) characterized by appropriate topological index~(winding number $W$). Interestingly, this system also hosts accidental zero modes~(AZMs) emerged with vanishing topological index indicating their non-topological nature. Furthermore, by incorporating three terminal setup, we explore the transport and shot noise signatures of these zero modes. At zero temperature, we obtain zero bias peak (ZBP) in differential conductance to be quantized with value $|W|\times 2 e^{2}/h$ for MZMs. On the other hand, AZMs exhibit non-quantized value at zero bias. Moreover, zero temperature shot noise manifests negative~(positive) value for MZMs~(AZMs) within the bulk gap. At finite temperature, shot noise exhibits negative value~(negative to positive transition) concerning MZMs~(AZMs). Thus, the obtained signatures clearly distinguish between the MZMs and non-topological AZMs. We extend our analysis by switching on the next to nearest neighbour hopping amplitude and SOC. Our conclusion remains unaffected for this case as well. Hence, our work paves the way to differentiate between emergent MZMs and AZMs in a semiconductor/ superconductor/ altermagnet heterostructure., Comment: 5+9 Pages, 4+5 PDF Figures, Comments are welcome
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- 2024
7. Follow-up of Neutron Star Mergers with CTA and Prospects for Joint Detection with Gravitational-Wave Detectors
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Mondal, T., Chakraborty, S., Resmi, L., and Bose, D.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
The joint gravitational wave (GW) and electromagnetic observations of the binary neutron star (BNS) merger GW170817 marked a giant leap in multi-messenger astrophysics. The extensive observation campaign of the associated Gamma-Ray Burst (GRB) and its afterglow has strengthened the hypothesis associating GRBs with BNS mergers and provided insights on mass ejection, particularly the relativistic outflow launched in BNS mergers. In this paper, we investigate the joint detection probabilities of BNS mergers by GW detectors and the upcoming ground-based very-high-energy (VHE) $\gamma$-ray instrument, the Cherenkov Telescope Array (CTA). Using an empirical relation that constrains the distance-inclination angle plane, we simulated BNS mergers detectable in the O5 run of the LIGO/Virgo/Kagra (LVK) network with $300$~Mpc BNS horizon. Assuming Gaussian structured jets and ignoring large sky localization challenges of GW detectors, we estimated VHE afterglow detection probability by CTA. We have explored the afterglow parameter space to identify conditions favourable for detecting synchrotron self-Compton emission by CTA. Our study reveals that events viewed at angles $\lesssim3$ times the jet core angle are detectable by CTA when the initial bulk Lorentz factor at the jet axis ranges between 100 and 800. We find high kinetic energy ($E_k>10^{50}$ erg), ambient density ($n_0>10^{-1}$ $cm^{-3}$), and energy content in non-thermal electrons significantly enhance the likelihood of CTA detection within 300 Mpc. The joint detection rate varies significantly with afterglow parameter distributions, ranging from $0.003$ to $0.5$ per year., Comment: 16 pages, 8 figures
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- 2024
8. ZKFault: Fault attack analysis on zero-knowledge based post-quantum digital signature schemes
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Mondal, Puja, Adhikary, Supriya, Kundu, Suparna, and Karmakar, Angshuman
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Computer Science - Cryptography and Security ,E.3.3 - Abstract
Computationally hard problems based on coding theory, such as the syndrome decoding problem, have been used for constructing secure cryptographic schemes for a long time. Schemes based on these problems are also assumed to be secure against quantum computers. However, these schemes are often considered impractical for real-world deployment due to large key sizes and inefficient computation time. In the recent call for standardization of additional post-quantum digital signatures by the National Institute of Standards and Technology, several code-based candidates have been proposed, including LESS, CROSS, and MEDS. These schemes are designed on the relatively new zero-knowledge framework. Although several works analyze the hardness of these schemes, there is hardly any work that examines the security of these schemes in the presence of physical attacks. In this work, we analyze these signature schemes from the perspective of fault attacks. All these schemes use a similar tree-based construction to compress the signature size. We attack this component of these schemes. Therefore, our attack is applicable to all of these schemes. In this work, we first analyze the LESS signature scheme and devise our attack. Furthermore, we showed how this attack can be extended to the CROSS signature scheme. Our attacks are built on very simple fault assumptions. Our results show that we can recover the entire secret key of LESS and CROSS using as little as a single fault. Finally, we propose various countermeasures to prevent these kinds of attacks and discuss their efficiency and shortcomings., Comment: 35 pages including appendix and bibliography
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- 2024
9. Seg-HGNN: Unsupervised and Light-Weight Image Segmentation with Hyperbolic Graph Neural Networks
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Mondal, Debjyoti, Mishra, Rahul, and Pandey, Chandan
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Image analysis in the euclidean space through linear hyperspaces is well studied. However, in the quest for more effective image representations, we turn to hyperbolic manifolds. They provide a compelling alternative to capture complex hierarchical relationships in images with remarkably small dimensionality. To demonstrate hyperbolic embeddings' competence, we introduce a light-weight hyperbolic graph neural network for image segmentation, encompassing patch-level features in a very small embedding size. Our solution, Seg-HGNN, surpasses the current best unsupervised method by 2.5\%, 4\% on VOC-07, VOC-12 for localization, and by 0.8\%, 1.3\% on CUB-200, ECSSD for segmentation, respectively. With less than 7.5k trainable parameters, Seg-HGNN delivers effective and fast ($\approx 2$ images/second) results on very standard GPUs like the GTX1650. This empirical evaluation presents compelling evidence of the efficacy and potential of hyperbolic representations for vision tasks., Comment: BMVC 2024
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- 2024
10. Detection of the Fe K lines from the binary AGN in 4C+37.11
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Mondal, Santanu, Das, Mousumi, Rubinur, K., Bansal, Karishma, Nath, Aniket, and Taylor, Greg B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the discovery of the Fe K line emission at $\sim6.62^{+0.06}_{-0.06}$ keV with a width of $\sim0.19^{+0.05}_{-0.05}$ keV using two epochs of {\it Chandra} archival data from the nucleus of the galaxy 4C+37.11, which is known to host a binary supermassive black hole (BSMBH) system where the SMBHs are separated by $\sim7$ mas or $\sim$ 7pc. Our study reports the first detection of the Fe K line from a known binary AGN, and has an F-statistic value of 20.98 and probability $2.47\times 10^{-12}$. Stacking of two spectra reveals another Fe K line component at $\sim7.87^{+0.19}_{-0.09}$ keV. Different model scenarios indicate that the lines originate from the combined effects of accretion disk emission and circumnuclear collisionally ionized medium. The observed low column density favors the gas-poor merger scenario, where the high temperature of the hot ionized medium may be associated with the shocked gas in the binary merger and not with star formation activity. The estimated total BSMBH mass and disk inclination are $\sim1.5\times10^{10}$ M$_\odot$ and $\gtrsim75^\circ$, indicating that the BSMBH is probably a high inclination system. The spin parameter could not be tightly constrained from the present data sets. Our results draw attention to the fact that detecting the Fe K line emissions from BSMBHs is important for estimating the individual SMBH masses, and the spins of the binary SMBHs, as well as exploring their emission regions., Comment: 7 pages, 1 table, 3 figure, Accepted in A&A
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- 2024
11. Dynamics in the nonequilibrium energy landscape of a frustrated Mott insulator
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Bakshi, Sankha Subhra, Mondal, Tanmoy, and Majumdar, Pinaki
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Condensed Matter - Strongly Correlated Electrons - Abstract
In a Mott insulator, a laser pulse with frequency tuned to the gap scale can create a holon-doublon plasma, suppressing the magnetic moment ${\vec m}_i$ and destroying magnetic order. While this disruptive effect is well established experimentally on a square lattice, we investigate the effect of laser pumping on the triangular lattice, where geometric frustration leads to a richer set of ordering possibilities. We work with the Mott-Hubbard problem at a coupling where $120^{\circ}$ order is just stable and employ spatio-temporal mean field dynamics to study the pump response. Moderate pump amplitude just leads to the reduction of $120^{\circ}$ order, but at larger amplitude the suppression of $120^{\circ}$ order is followed by the appearance of `spiral order'. On the electronic side the density of `excited carriers' $n_{exc}$ in the upper Hubbard band increases monotonically with pump amplitude. We show that the long time ordering possibilities in the pumped system, e.g., the emergence of spiral order, can be inferred from a nonequilibrium `energy landscape'. We analyse the growth of spiral order by using an exact diagonalisation based Langevin equation on large lattices and discover that the new order can take $\sim 10^3-10^4$ times the electronic timescale to appear. The threefold combination, of mean field dynamics, landscape construction, and Langevin dynamics, readily generalises to the search for pump induced `hidden order' in other gapped systems., Comment: 13 pages, 9 figures
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- 2024
12. Do Android App Developers Accurately Report Collection of Privacy-Related Data?
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Khedkar, Mugdha, Mondal, Ambuj Kumar, and Bodden, Eric
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Computer Science - Cryptography and Security - Abstract
Many Android applications collect data from users. The European Union's General Data Protection Regulation (GDPR) requires vendors to faithfully disclose which data their apps collect. This task is complicated because many apps use third-party code for which the same information is not readily available. Hence we ask: how accurately do current Android apps fulfill these requirements? In this work, we first expose a multi-layered definition of privacy-related data to correctly report data collection in Android apps. We further create a dataset of privacy-sensitive data classes that may be used as input by an Android app. This dataset takes into account data collected both through the user interface and system APIs. We manually examine the data safety sections of 70 Android apps to observe how data collection is reported, identifying instances of over- and under-reporting. Additionally, we develop a prototype to statically extract and label privacy-related data collected via app source code, user interfaces, and permissions. Comparing the prototype's results with the data safety sections of 20 apps reveals reporting discrepancies. Using the results from two Messaging and Social Media apps (Signal and Instagram), we discuss how app developers under-report and over-report data collection, respectively, and identify inaccurately reported data categories. Our results show that app developers struggle to accurately report data collection, either due to Google's abstract definition of collected data or insufficient existing tool support., Comment: Accepted at the 7th International Workshop on Advances in Mobile App Analysis held in conjunction with ASE 2024
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- 2024
13. Emergence of two inertial sub-ranges in solar wind turbulence: dependence on heliospheric distance and solar activity
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Mondal, Shiladittya, Banerjee, Supratik, and Sorriso-Valvo, Luca
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Physics - Space Physics ,Astrophysics - Solar and Stellar Astrophysics ,Physics - Plasma Physics - Abstract
The solar wind is highly turbulent, and intermittency effects are observed for fluctuations within the inertial range. By analyzing magnetic field spectra and fourth-order moments, we perform a comparative study of intermittency in different types of solar wind measured during periods of solar minima and a maximum. Using eight fast solar wind intervals measured during solar minima between 0.3 au and 3.16 au, we found a clear signature of two inertial sub-ranges with $f^{-3/2}$ and $f^{-5/3}$ power laws in the magnetic power spectra. The intermittency, measured through the scaling law of the kurtosis of magnetic field fluctuations, further confirms the existence of two different power laws separated by a clear break. A systematic study on the evolution of the said sub-ranges as a function of heliospheric distance shows correlation of the break scale with both the turbulence outer scale and the typical ion scales. During solar maximum, we analyzed five intervals for each of Alfv\'enic fast, Alfv\'enic slow and non-Alfv\'enic slow solar wind. Unlike the case during the solar minima, the two sub-ranges are no longer prominent and the Alfv\'enic slow wind is found to be in an intermediate state of turbulence compared to that of the fast wind and the usual non-Alfv\'enic slow wind., Comment: 16 pages, 11 figures, submitted to ApJ
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- 2024
14. Non-harmonic analysis of the wave equation for Schr\'{o}dinger operators with complex potential
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Dasgupta, Aparajita, Mohan, Lalit, and Mondal, Shyam Swarup
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Mathematics - Analysis of PDEs ,Primary 46F05, Secondary 58J40, 22E30 - Abstract
This article investigates the wave equation for the Schr\"{o}dinger operator on $\mathbb{R}^{n}$, denoted as $\mathcal{H}_0:=-\Delta+V$, where $\Delta$ is the standard Laplacian and $V$ is a complex-valued multiplication operator. We prove that the operator $\mathcal{H}_0$, with $\operatorname{Re}(V)\geq 0$ and $\operatorname{Re}(V)(x)\to\infty$ as $|x|\to\infty$, has a purely discrete spectrum under certain conditions. In the spirit of Colombini, De Giorgi, and Spagnolo, we also prove that the Cauchy problem with regular coefficients is well-posed in the associated Sobolev spaces, and when the propagation speed is H\"{o}lder continuous (or more regular), it is well-posed in Gevrey spaces. Furthermore, we prove that it is very weakly well-posed when the coefficients possess a distributional singularity., Comment: 25 pages
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- 2024
15. Strengthening Solidity Invariant Generation: From Post- to Pre-Deployment
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Kaushik, Kartik, Halder, Raju, and Mondal, Samrat
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Computer Science - Software Engineering ,Computer Science - Programming Languages - Abstract
Invariants are essential for ensuring the security and correctness of Solidity smart contracts, particularly in the context of blockchain's immutability and decentralized execution. This paper introduces InvSol, a novel framework for pre-deployment invariant generation tailored specifically for Solidity smart contracts. Unlike existing solutions, namely InvCon, InvCon+, and Trace2Inv, that rely on post-deployment transaction histories on Ethereum mainnet, InvSol identifies invariants before deployment and offers comprehensive coverage of Solidity language constructs, including loops. Additionally, InvSol incorporates custom templates to effectively prevent critical issues such as reentrancy, out-of-gas errors, and exceptions during invariant generation. We rigorously evaluate InvSol using a benchmark set of smart contracts and compare its performance with state-of-the-art solutions. Our findings reveal that InvSol significantly outperforms these tools, demonstrating its effectiveness in handling new contracts with limited transaction histories. Notably, InvSol achieves a 15% improvement in identifying common vulnerabilities compared to InvCon+ and is able to address certain crucial vulnerabilities using specific invariant templates, better than Trace2Inv.
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- 2024
16. Understanding Charge Transport in Single Molecule of Rhenium(I) Compounds: A Computational Approach
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Kaur, Rajwinder, Kaya, Savas, Katin, Konstantin P., and Mondal, Prakash Chandra
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Condensed Matter - Materials Science - Abstract
Understanding electrical characteristics and corresponding transport models at single molecular junctions is crucial. There have been many reports on organic compounds-based single molecular junctions. However, organometallic compounds-based single molecular junctions have not been explored yet. Re(I) organometallic compounds are known to exhibit intriguing photophysical properties scrutinized for photocatalysis, and light-emitting diodes but have not been explored in molecular electronics. In this work, a theoretical model study on the I-V characteristics of two Re(I)-carbonyl complexes bearing Re-P and Re-N-N linkage has been meticulously chosen. Tunneling and hopping transport in Au/Re(I)-complex/Au single-molecule junctions are governed by Landauer-formalism and the Marcus theory, respectively. Interestingly, variations in molecular architecture culminate in notable variations in junction functionality and mechanism of charge conduction. Physical parameters influencing the device characteristics such as dipole moment, molecule-electrode coupling strength, voltage division factor, and temperature have been extensively studied which offers modulation of the characteristics and device design. The dominant hopping current in Re complex bearing bipyridine linkage was found to be responsible for the observed asymmetric electrical (I-V) behavior. Our work paves the way for constructing various organometallic compounds-based molecular junctions to understand electronic functions and the underlying transport mechanisms., Comment: 17 pages, 8 figures
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- 2024
17. Theory of tensorial magnetic inertia in terahertz spin dynamics
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Ghosh, Subhadip, Cherkasskii, Mikhail, Barsukov, Igor, and Mondal, Ritwik
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Condensed Matter - Mesoscale and Nanoscale Physics ,Physics - Applied Physics - Abstract
Magnetic inertia has emerged as a possible way to manipulate ferromagnetic spins at a higher frequency e.g., THz. Theoretical treatments so far have considered the magnetic inertia as a scalar quantity. Here, we explore the magnetic inertial dynamics with a magnetic inertia tensor as macroscopic derivations predicted it to be a tensor. First, the inertia tensor has been decomposed into three terms: (a) scalar and isotropic inertia, (b) anisotropic and symmetric inertia tensor, (c) chiral and antisymmetric tensor. Further, we employ linear response theory to the inertial Landau-Lifshitz-Gilbert equation with the inertia tensor and calculate the effect of chiral and anisotropic inertia on ferromagnets, antiferromagnets, and ferrimagnets. It is established that the precession and nutation resonance frequencies decrease with scalar magnetic inertia. Our results suggest that the nutation resonance frequencies further reduce due to inertia tensor. However, the effective damping of the nutation resonance increases with the chiral and antisymmetric part of the inertia tensor. We show that the precession resonances remain unaffected, while the nutation resonances are modified with the chiral magnetic inertia., Comment: 13 pages, 8 figures
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- 2024
18. Unprecedented Enhancement of Piezoelectricity in Wurtzite Nitride Semiconductors via Thermal Annealing
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Mondal, Shubham, Tanim, Md Mehedi Hasan, Baucom, Garrett, Dabas, Shaurya S., Gao, Jinghan, Gaddam, Venkateswarlu, Liu, Jiangnan, Ross, Aiden, Chen, Long-Qing, Kim, Honggyu, Tabrizian, Roozbeh, and Mi, Zetian
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Condensed Matter - Materials Science - Abstract
The incorporation of rare-earth elements in wurtzite nitride semiconductors, e.g., scandium alloyed aluminum nitride (ScAlN), promises dramatically enhanced piezoelectric responses, critical to a broad range of acoustic, electronic, photonic, and quantum devices and applications. Experimentally, however, the measured piezoelectric responses of nitride semiconductors are far below what theory has predicted. Here, we show that the use of a simple, scalable, post-growth thermal annealing process can dramatically boost the piezoelectric response of ScAlN thin films. We achieve a remarkable 3.5-fold increase in the piezoelectric modulus, d33 for 30% Sc content ScAlN, from 12.3 pC/N in the as-grown state to 45.5 pC/N, which is eight times larger than that of AlN. The enhancement in piezoelectricity has been unambiguously confirmed by three separate measurement techniques. Such a dramatic enhancement of d33 has been shown to impact the effective electromechanical coupling coefficient kt2 : increasing it from 13.8% to 76.2%, which matches the highest reported values in millimeter thick lithium niobate films but is achieved in a 100 nm ScAlN with a 10,000 fold reduction in thickness, thus promising extreme frequency scaling opportunities for bulk acoustic wave resonators for beyond 5G applications. By utilizing a range of material characterization techniques, we have elucidated the underlying mechanisms for the dramatically enhanced piezoelectric responses, including improved structural quality at the macroscopic scale, more homogeneous and ordered distribution of domain structures at the mesoscopic scale, and the reduction of lattice parameter ratio (c/a) for the wurtzite crystal structure at the atomic scale. Overall, the findings present a simple yet highly effective pathway that can be extended to other material families to further enhance their piezo responses.
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- 2024
19. AUTOGENICS: Automated Generation of Context-Aware Inline Comments for Code Snippets on Programming Q&A Sites Using LLM
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Bappon, Suborno Deb, Mondal, Saikat, and Roy, Banani
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Computer Science - Software Engineering - Abstract
Inline comments in the source code facilitate easy comprehension, reusability, and enhanced readability. However, code snippets in answers on Q&A sites like Stack Overflow (SO) often lack comments because answerers volunteer their time and often skip comments or explanations due to time constraints. Existing studies show that these online code examples are difficult to read and understand, making it difficult for developers (especially novices) to use them correctly and leading to misuse. Given these challenges, we introduced AUTOGENICS, a tool designed to integrate with SO to generate effective inline comments for code snippets in SO answers exploiting large language models (LLMs). Our contributions are threefold. First, we randomly select 400 answer code snippets from SO and generate inline comments for them using LLMs. We then manually evaluate these comments' effectiveness using four key metrics: accuracy, adequacy, conciseness, and usefulness. Overall, LLMs demonstrate promising effectiveness in generating inline comments for SO answer code snippets. Second, we surveyed 14 active SO users to perceive the effectiveness of these inline comments. The survey results are consistent with our previous manual evaluation. However, according to our evaluation, LLMs-generated comments are less effective for shorter code snippets and sometimes produce noisy comments. Third, to address the gaps, we introduced AUTOGENICS, which extracts additional context from question texts and generates context-aware inline comments. It also optimizes comments by removing noise (e.g., comments in import statements and variable declarations). We evaluate the effectiveness of AUTOGENICS-generated comments using the same four metrics that outperform those of standard LLMs. AUTOGENICS might (a) enhance code comprehension, (b) save time, and improve developers' ability to learn and reuse code more accurately., Comment: Accepted for presentation in the research track at the IEEE International Conference on Source Code Analysis & Manipulation (SCAM 2025)
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- 2024
20. Multipath entanglement purification strategies for quantum networks
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Mondal, Md Sohel and Santra, Siddhartha
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Quantum Physics - Abstract
In quantum networks multipath entanglement purification (MEP) between a pair of source-destination nodes can substantially strengthen their entanglement connection. An efficient MEP strategy can therefore increase the size of the network region where bipartite entanglement based quantum information processing tasks can be implemented. Here, we analyse MEP in a general model of a quantum network and obtain design criteria for efficient MEP strategies. Further, by simulating two different MEP strategies, based on these criteria, on different underlying network topologies we explore how the topology determines the effectiveness of a fixed MEP strategy. Finally, we show that a careful choice of MEP strategy can make the entanglement connection strength between source-destination network nodes effectively independent of its topology. Our results can therefore provide a useful guide for the design of quantum networks and entanglement distribution protocols.
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- 2024
- Full Text
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21. New Insights into Type-I Solar Noise Storms from High Angular Resolution Spectroscopic Imaging with the upgraded Giant Metrewave Radio Telescope
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Mondal, Surajit, Kansabanik, Devojyoti, Oberoi, Divya, and Dey, Soham
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Astrophysics - Solar and Stellar Astrophysics - Abstract
Type-I solar noise storms are perhaps the most commonly observed active radio emissions from the Sun at meter-wavelengths. Noise storms have a long-lived and wideband continuum background with superposed islands of much brighter narrowband and short-lived emissions, known as type-I bursts. There is a serious paucity of studies focusing on the morphology of these two types of emissions, primarily because of the belief that coronal scattering will always wash out any features at small angular scales. However, it is important to { investigate} their spatial structures in detail to make a spatio-temporal connection with observations at extreme-ultraviolet/ X-ray bands to understand the detailed nature of these emissions. In this work, we use high angular resolution observations from the upgraded Giant Metrewave Radio Telescope to demonstrate that it is possible to detect structures with angular scales as small as $\sim 9\arcsec$, about three times smaller than the smallest structure reported to date from noise storms. Our observations also suggest while the individual type-I bursts are narrowband in nature, the bursts are probably caused by traveling disturbance(s) inducing magnetic reconnections at different coronal heights, and thus leading to correlated change in the morphology of the type-I bursts observed at a wide range of frequencies., Comment: Accepted for publication in the Astrophysical Journal
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- 2024
22. Analysis of a special type of soliton on Kenmotsu manifolds
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Mondal, Somnath, Khan, Meraj Ali, Dey, Santu, Sarkar, Ashis Kumar, Ozel, Cenap, Pigazzini, Alexander, and Pincak, Richard
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Physics - General Physics - Abstract
In this paper, we aim to investigate the properties of an almost $*$-Ricci-Bourguignon soliton (almost $*-$R-B-S for short) on a Kenmotsu manifold (K-M). We start by proving that if a Kenmotsu manifold (K-M) obeys an almost $*-$R-B-S, then the manifold is $\eta$-Einstein. Furthermore, we establish that if a $(\kappa, -2)'$-nullity distribution, where $\kappa<-1$, has an almost $*$-Ricci-Bourguignon soliton (almost $*-$R-B-S), then the manifold is Ricci flat. Moreover, we establish that if a K-M has almost $*$-Ricci-Bourguignon soliton gradient and the vector field $\xi$ preserves the scalar curvature $r$, then the manifold is an Einstein manifold with a constant scalar curvature given by $r=-n(2n-1)$. Finaly, we have given en example of a almost $*-$R-B-S gradient on the Kenmotsu manifold., Comment: 22 pages
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- 2024
23. Towards a Resource-Optimized Dynamic Quantum Algorithm via Non-iterative Auxiliary Subspace Corrections
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Patra, Chayan, Mukherjee, Debaarjun, Halder, Sonaldeep, Mondal, Dibyendu, and Maitra, Rahul
- Subjects
Quantum Physics - Abstract
Recent quantum algorithms pertaining to electronic structure theory primarily focus on threshold-based dynamic construction of ansatz by selectively including important many-body operators. These methods can be made systematically more accurate by tuning the threshold to include more number of operators into the ansatz. However, such improvements come at the cost of rapid proliferation of the circuit depth, especially for highly correlated molecular systems. In this work, we address this issue by the development of a novel theoretical framework that relies on the segregation of an ansatz into a dynamically selected core principal component, which is, by construction adiabatically decoupled from the remaining operators. This enables us to perform computations involving the principal component using extremely shallow-depth circuits whereas, the effect of the remaining auxiliary component is folded into the energy function via a cost-efficient non-iterative correction, ensuring the requisite accuracy. We propose a formalism that analytically predicts the auxiliary parameters from the principal ones, followed by a suite of non-iterative auxiliary subspace correction techniques with different levels of sophistication. The auxiliary subspace corrections incur no additional quantum resources, yet complement an inadequately expressive core of the ansatz to recover significant amount of electronic correlations. We have numerically validated the resource efficiency and accuracy of our formalism with a number of strongly correlated molecular systems., Comment: 14 pages, 5 figures
- Published
- 2024
24. Thermal and non-thermal dark matters with gravitational neutrino reheating
- Author
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Haque, Md Riajul, Maity, Debaprasad, and Mondal, Rajesh
- Subjects
High Energy Physics - Phenomenology ,Astrophysics - Cosmology and Nongalactic Astrophysics ,General Relativity and Quantum Cosmology ,High Energy Physics - Theory - Abstract
We have discussed in detail how neutrinos produced from inflaton solely through gravitational interaction can successfully reheat the universe. For this, we have introduced the well-known Type-I seesaw neutrino model. Depending on seesaw model parameters, two distinct reheating histories have been realized and dubbed as i) Neutrino dominating: Following the inflaton domination, the universe becomes neutrino dominated, and their subsequent decay concludes the reheating process, and ii) Neutrino heating: Despite being sub-dominant compared to inflaton energy, neutrinos efficiently heat the thermal bath and produce the radiation dominated universe. Imposing baryon asymmetric yield, the $\Delta N_{\rm eff}$ constraint at Big Bang Nucleosynthesis (BBN) considering primordial gravitational waves (PGW), we have arrived at the following constraints on reheating equation of state to lie within $0.5\lesssim w_\phi\lesssim1.0$. In these neutrino-driven reheating backgrounds, we further performed a detailed analysis of both thermal and non-thermal production of dark matter (DM), invoking two minimal models, namely the Higgs portal DM and classical QCD pseudo scalar axion. An interesting correlation between seemingly uncorrelated DM and Type-I seesaw parameters has emerged when confronting various direct and indirect observations. When DMs are set to freeze-in, freeze-out, or oscillate during reheating, new parameter spaces open, which could be potentially detectable in future experiments, paving an indirect way to look into the early universe in the laboratory., Comment: 24 pages,13 figures, 3 tables
- Published
- 2024
25. Time Optimal Distance-$k$-Dispersion on Dynamic Ring
- Author
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Mondal, Brati, Goswami, Pritam, and Sau, Buddhadeb
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
Dispersion by mobile agents is a well studied problem in the literature on computing by mobile robots. In this problem, $l$ robots placed arbitrarily on nodes of a network having $n$ nodes are asked to relocate themselves autonomously so that each node contains at most $\lfloor \frac{l}{n}\rfloor$ robots. When $l\le n$, then each node of the network contains at most one robot. Recently, in NETYS'23, Kaur et al. introduced a variant of dispersion called \emph{Distance-2-Dispersion}. In this problem, $l$ robots have to solve dispersion with an extra condition that no two adjacent nodes contain robots. In this work, we generalize the problem of Dispersion and Distance-2-Dispersion by introducing another variant called \emph{Distance-$k$-Dispersion (D-$k$-D)}. In this problem, the robots have to disperse on a network in such a way that shortest distance between any two pair of robots is at least $k$ and there exist at least one pair of robots for which the shortest distance is exactly $k$. Note that, when $k=1$ we have normal dispersion and when $k=2$ we have D-$2$-D. Here, we studied this variant for a dynamic ring (1-interval connected ring) for rooted initial configuration. We have proved the necessity of fully synchronous scheduler to solve this problem and provided an algorithm that solves D-$k$-D in $\Theta(n)$ rounds under a fully synchronous scheduler. So, the presented algorithm is time optimal too. To the best of our knowledge, this is the first work that considers this specific variant.
- Published
- 2024
26. Last-Iterate Convergence of General Parameterized Policies in Constrained MDPs
- Author
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Mondal, Washim Uddin and Aggarwal, Vaneet
- Subjects
Computer Science - Machine Learning ,Computer Science - Artificial Intelligence - Abstract
We consider the problem of learning a Constrained Markov Decision Process (CMDP) via general parameterization. Our proposed Primal-Dual based Regularized Accelerated Natural Policy Gradient (PDR-ANPG) algorithm uses entropy and quadratic regularizers to reach this goal. For a parameterized policy class with transferred compatibility approximation error, $\epsilon_{\mathrm{bias}}$, PDR-ANPG achieves a last-iterate $\epsilon$ optimality gap and $\epsilon$ constraint violation (up to some additive factor of $\epsilon_{\mathrm{bias}}$) with a sample complexity of $\tilde{\mathcal{O}}(\epsilon^{-2}\min\{\epsilon^{-2},\epsilon_{\mathrm{bias}}^{-\frac{1}{3}}\})$. If the class is incomplete ($\epsilon_{\mathrm{bias}}>0$), then the sample complexity reduces to $\tilde{\mathcal{O}}(\epsilon^{-2})$ for $\epsilon<(\epsilon_{\mathrm{bias}})^{\frac{1}{6}}$. Moreover, for complete policies with $\epsilon_{\mathrm{bias}}=0$, our algorithm achieves a last-iterate $\epsilon$ optimality gap and $\epsilon$ constraint violation with $\tilde{\mathcal{O}}(\epsilon^{-4})$ sample complexity. It is a significant improvement of the state-of-the-art last-iterate guarantees of general parameterized CMDPs.
- Published
- 2024
27. RIS-Vis: A Novel Visualization Platform for Seismic, Geodetic, and Weather Data Relevant to Antarctic Cryosphere Science
- Author
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Chakravarthy, Aishwarya, Mondal, Dhiman, Barrett, John, Ruszczyk, Chet, and Elosegui, Pedro
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Physics - Atmospheric and Oceanic Physics ,Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Antarctic ice shelves play a vital role in preserving the physical conditions of the Antarctic cryosphere and the Southern Ocean, and beyond. By serving as a buttressing force, ice shelves prevent sea-level rise by restraining the flow of continental ice and glaciers to the sea. Sea-level rise impacts the global environment in multiple ways, including flooding habitats, eroding coastlines, and contaminating soil and groundwater. It is therefore essential to monitor the stability of Antarctic ice shelves, for which a variety of complementary data sources is required. We have developed RIS-Vis, a novel data visualization platform to monitor Antarctic ice shelves. Although focused on the Ross Ice Shelf (RIS), RIS-Vis could be readily scaled to monitor other ice shelves around Antarctica, and elsewhere. Currently, RIS-Vis is capable of analyzing and visualizing seismic, geodetic, and weather data to provide meaningful information for Antarctic cryosphere research. RIS-Vis was built using Python libraries including Obspy, APScheduler, and the Plotly Dash framework, and uses SQLite as the backing database. Visualizations developed on RIS-Vis include filtered seismic waveforms, spectrograms, and power spectral densities, geodetic-based ice-shelf flow, and meteorological variables such as atmospheric temperature and pressure. The dashboard visualization platform abstracts away the time-intensive analysis process of raw data and allows scientists to better concentrate on RIS science.
- Published
- 2024
28. Towards a first principles light-front Hamiltonian for the nucleon
- Author
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Xu, Siqi, Liu, Yiping, Mondal, Chandan, Lan, Jiangshan, Zhao, Xingbo, Li, Yang, and Vary, James P.
- Subjects
High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We solve the nucleon's wave functions from the eigenstates of the light-front quantum chromodynamics Hamiltonian for the first time, using a fully relativistic and nonperturbative approach based on light-front quantization, without an explicit confining potential. These eigenstates are determined for the three-quark, three-quark-gluon, and three-quark-quark-antiquark Fock representations, making them suitable for low-resolution probes. From this, we calculate the nucleon's quark and gluon matter densities, helicity, and transversity distributions, which show qualitative consistency with experimental extractions. We also compute the contributions of quark and gluon helicity to the proton spin and the tensor charges. The obtained light-front wave functions represent a significant advancement towards a unified description of various hadron distribution functions in both longitudinal and transverse momentum space.
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- 2024
29. Surface Tension of a Topological Phase
- Author
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Mondal, Saikat and Agarwala, Adhip
- Subjects
Condensed Matter - Statistical Mechanics ,Condensed Matter - Soft Condensed Matter ,Condensed Matter - Strongly Correlated Electrons - Abstract
Metastable phases, in general, are unstable to nucleating droplets of the order defining the global free energy minima. However, whether such a droplet grows or shrinks relies on a competition between the surface tension and bulk energy density. We study the role of coupling a topological fermionic field to a scalar field undergoing such nucleation processes. We find that existence of non-trivial fermionic boundary modes on the nucleating droplets leads to substantial quantum corrections to the surface tension thereby modifying the size of the critical nucleus beyond which unrestricted droplet growth happens. To illustrate the phenomena we devise a minimal model of fermions in a Chern insulating system coupled to a classical Ising field in two spatial dimensions. Using a combination of analytic and numerical methods we conclusively show that topological phases can lead to characteristic quantum surface tension. Apart from material systems, our work has implications on the interplay of physics of statistical classical fields and quantum topological order., Comment: 6+2 pages, 4+2 Figures
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- 2024
30. Chiral-odd gluon generalized parton distributions in the proton: A light-front quantization approach
- Author
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Lin, Bolang, Nair, Sreeraj, Mondal, Chandan, Xu, Siqi, Hu, Zhi, Zhang, Pengxiang, Zhao, Xingbo, and Vary, James P.
- Subjects
High Energy Physics - Phenomenology - Abstract
Within the basis light-front quantization (BLFQ) framework, we evaluate the gluon chiral-odd generalized parton distributions (GPDs) inside the proton at zero skewness. We employ the light-front wave functions of the proton obtained from a light-front quantized Hamiltonian with quantum chromodynamics input using BLFQ. Our investigation encompasses both the valence Fock sector with three constituent quarks and an additional sector containing three quarks and a dynamical gluon. We analyze the gluon GPDs in the momentum space as well as in the transverse position space. We further present the gluon's generalized form factors derived from the Mellin moments of its chiral-odd GPDs. Using the proton transverse spin sum rule, we also present the $x$-dependence of the angular momentum carried by the polarized gluon and determine the relative contributions of quarks and the gluon to the transversity asymmetry., Comment: 11 pages, 12 figures
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- 2024
31. Noisy information channel mediated prevention of the tragedy of the commons
- Author
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Mondal, Samrat Sohel and Chakraborty, Sagar
- Subjects
Quantitative Biology - Populations and Evolution ,Physics - Physics and Society - Abstract
Synergy between evolutionary dynamics of cooperation and fluctuating state of shared resource being consumed by the cooperators is essential for averting the tragedy of the commons. Not only in humans, but also in the cognitively-limited organisms, this interplay between the resource and the cooperation is ubiquitously witnessed. The strategically interacting players engaged in such game-environment feedback scenarios naturally pick strategies based on their perception of the environmental state. Such perception invariably happens through some sensory information channels that the players are endowed with. The unfortunate reality is that any sensory channel must be noisy due to various factors; consequently, the perception of the environmental state becomes faulty rendering the players incapable of adopting the strategy that they otherwise would. Intriguingly, situation is not as bad as it sounds. Here we introduce the hitherto neglected information channel between players and the environment into the paradigm of stochastic evolutionary games with a view to bringing forward the counterintuitive possibility of emergence and sustenance of cooperation on account of the noise in the channel. Our primary study is in the simplest non-trivial setting of two-state stochastically fluctuating resource harnessed by a large unstructured population of cooperators and defectors adopting either memory-1 strategies or reactive strategies while engaged in repeated two-player interactions. The effect of noisy information channel in enhancing the cooperation in reactive-strategied population is unprecedented. We find that the propensity of cooperation in the population is inversely related to the mutual information (normalized by the channel capacity) of the corresponding information channel.
- Published
- 2024
32. Spin Hall Nano-Antenna
- Author
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Fabiha, Raisa, Pal, Pratap Kumar, Suche, Michael, Mondal, Amrit Kumar, Topsakal, Erdem, Barman, Anjan, and Bandyopadhyay, Supriyo
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Electrical Engineering and Systems Science - Systems and Control ,Physics - Applied Physics - Abstract
The spin Hall effect is a celebrated phenomenon in spintronics and magnetism that has found numerous applications in digital electronics (memory and logic), but very few in analog electronics. Practically, the only analog application in widespread use is the spin Hall nano-oscillator (SHNO) that delivers a high frequency alternating current or voltage to a load. Here, we report its analogue - a spin Hall nano-antenna (SHNA) that radiates a high frequency electromagnetic wave (alternating electric/magnetic fields) into the surrounding medium. It can also radiate an acoustic wave in an underlying substrate if the nanomagnets are made of a magnetostrictive material. That makes it a dual electromagnetic/acoustic antenna. The SHNA is made of an array of ledged magnetostrictive nanomagnets deposited on a substrate, with a heavy metal nanostrip underlying/overlying the ledges. An alternating charge current passed through the nanostrip generates an alternating spin-orbit torque in the nanomagnets via the spin Hall effect which makes their magnetizations oscillate in time with the frequency of the current, producing confined spin waves (magnons), which radiate electromagnetic waves (photons) in space with the same frequency as the ac current. Despite being much smaller than the radiated wavelength, the SHNA surprisingly does not act as a point source which would radiate isotropically. Instead, there is clear directionality (anisotropy) in the radiation pattern, which is frequency-dependent. This is due to the (frequency-dependent) intrinsic anisotropy in the confined spin wave patterns generated within the nanomagnets, which effectively endows the "point source" with internal anisotropy.
- Published
- 2024
33. Optical Music Recognition in Manuscripts from the Ricordi Archive
- Author
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Simonetta, Federico, Mondal, Rishav, Ludovico, Luca Andrea, and Ntalampiras, Stavros
- Subjects
Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence ,Computer Science - Digital Libraries - Abstract
The Ricordi archive, a prestigious collection of significant musical manuscripts from renowned opera composers such as Donizetti, Verdi and Puccini, has been digitized. This process has allowed us to automatically extract samples that represent various musical elements depicted on the manuscripts, including notes, staves, clefs, erasures, and composer's annotations, among others. To distinguish between digitization noise and actual music elements, a subset of these images was meticulously grouped and labeled by multiple individuals into several classes. After assessing the consistency of the annotations, we trained multiple neural network-based classifiers to differentiate between the identified music elements. The primary objective of this study was to evaluate the reliability of these classifiers, with the ultimate goal of using them for the automatic categorization of the remaining unannotated data set. The dataset, complemented by manual annotations, models, and source code used in these experiments are publicly accessible for replication purposes., Comment: Accepted at AudioMostly 2024
- Published
- 2024
- Full Text
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34. Pion to photon transition form factor: Beyond valence quarks
- Author
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Wu, Xiaoyi, Zhu, Zhimin, Lin, Ziyang, Mondal, Chandan, Lan, Jiangshan, Zhao, Xingbo, and Vary, James P.
- Subjects
High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We investigate the singly virtual transition form factor (TFF) for the $\pi^0\to\gamma^*\gamma$ process in the space-like region using the hard-scattering formalism within the Basis Light-Front Quantization (BLFQ) framework. This form factor is expressed in terms of the perturbatively calculable hard-scattering amplitudes (HSAs) and the light-front wave functions (LFWFs) of the pion. We obtain the pion LFWFs by diagonalizing the light-front QCD Hamiltonian, which is determined for its constituent quark-antiquark and quark-antiquark-gluon Fock sectors with a three-dimensional confinement. We employ the HSAs up to next-to-leading order (NLO) in the quark-antiquark Fock sector and leading order (LO) in the quark-antiquark-gluon Fock sector. The NLO correction to the TFF in the quark-antiquark Fock sector is of the same order as the LO contribution to the TFF in the quark-antiquark-gluon Fock sector. We find that while the quark-antiquark-gluon Fock sector has minimal effect in the large momentum transfer ($Q^2$) region, it has a noteworthy impact in the low-$Q^2$ region. Our results show that, after accounting for both Fock sectors, the TFF within the BLFQ framework aligns well with existing experimental data, particularly in the low $Q^2$ region., Comment: The manuscript consists of 9 pages, 1 table, and 3 figures
- Published
- 2024
35. Proton gluonic distributions in a light front spectator model
- Author
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Choudhary, Poonam, Chakrabarti, Dipankar, Gurjar, Bheemsehan, Maji, Tanmay, Mondal, Chandan, and Mukherjee, Asmita
- Subjects
High Energy Physics - Phenomenology - Abstract
We investigate the leading-twist gluonic distribution functions within the proton by formulating a light-front spectator model. The proton light-front wave functions (LFWFs) are adopted from the soft-wall AdS/QCD predictions, and the model parameters are determined using the gluon unpolarized parton distribution function from the NNPDF3.0nlo dataset. Furthermore, we demonstrated the model calculations for gluon transverse momentum distributions (TMDs) and generalized parton distributions (GPDs). We also predicted the gluon spin and orbital angular momentum (OAM) contributions to the total proton spin., Comment: Contribution to the 31st International Workshop on Deep Inelastic Scattering (DIS2024), 8-12 April 2024, Grenoble, France
- Published
- 2024
36. Relativistic X-ray reflection from the accreting millisecond X-ray pulsar IGR J17498-2921
- Author
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Bhattacharya, Mahasweta, Mondal, Aditya S., Pahari, Mayukh, Raychaudhuri, Biplab, Ghosh, Rohit, and Dewangan, Gulab C.
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
The accreting millisecond X-ray pulsar IGR J17498-2921 went into X-ray outburst on April 13-15, 2023, for the first time since its discovery on August 11, 2011. Here, we report on the first follow-up \nustar{} observation of the source, performed on April 23, 2023, around ten days after the peak of the outburst. The \nustar{} spectrum of the persistent emission ($3-60$ \kev{} band) is well described by an absorbed blackbody with a temperature of $kT_{bb}=1.61\pm 0.04$\kev{}, most likely arising from the NS surface and a Comptonization component with power-law index $\Gamma=1.79\pm0.02$, arising from a hot corona at $kT_{e}=16\pm 2$ keV. The X-ray spectrum of the source shows robust reflection features which have not been observed before. We use a couple of self-consistent reflection models, {\tt relxill} and {\tt relxillCp}, to fit the reflection features. We find an upper limit to the inner disc radius of $ 6\: R_{ISCO}$ and $ 9\: R_{ISCO}$ from {\tt relxill} and {\tt relxillCp} model, respectively. The inclination of the system is estimated to be $\simeq 40\degr$ from both reflection models. Assuming magnetic truncation of the accretion disc, the upper limit of magnetic field strength at the pole of the NS is found to be $B\lesssim 1.8\times 10^{8}$ G. Furthermore, the \nustar{} observation revealed two type I X-ray bursts and the burst spectroscopy confirms the thermonuclear nature of the burst. The blackbody temperature reaches nearly $2.2$ keV at the peak of the burst., Comment: 13 pages, 17 figures, Accepted for publication in MNRAS main journal
- Published
- 2024
37. Higher order hypoelliptic damped wave equations on graded Lie groups with data from negative order Sobolev spaces: the critical case
- Author
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Kumar, Vishvesh, Mondal, Shyam Swarup, Ruzhansky, Michael, and Torebek, Berikbol T.
- Subjects
Mathematics - Analysis of PDEs ,Primary 43A80, 35L15, 35L71, 35A01, Secondary 35L15, 35B33, 35B44 - Abstract
Let $\mathbb G$ be a graded Lie group with homogeneous dimension $Q$. In this paper, we study the Cauchy problem for a semilinear hypoelliptic damped wave equation involving a positive Rockland operator $\mathcal{R}$ of homogeneous degree $\nu\geq 2$ on $\mathbb G$ with power type nonlinearity $|u|^p$ and initial data taken from negative order homogeneous Sobolev space $\dot H^{-\gamma}(\mathbb G), \gamma>0,$ for the critical exponent case $p=1+\frac{2\nu}{Q+2\gamma}.$ We also explore the diffusion phenomenon of the higher-order hypoelliptic damped wave equations on graded Lie groups with initial data belonging to Sobolev spaces of negative order. We emphasize that our results are also new, even in the setting of higher-order differential operators on $\mathbb{R}^n$, and more generally, on stratified Lie groups., Comment: The previous incorrect version should be ignored, replaced by the current version, which is also done in the setting of general graded Lie groups. arXiv admin note: substantial text overlap with arXiv:2404.08766
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- 2024
38. Experimental observation of relativistic field-derivative torque in nonlinear THz response of magnetization dynamics
- Author
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Dutta, Arpita, Tzschaschel, Christian, Priyadarshi, Debankit, Mikuni, Kouki, Satoh, Takuya, Mondal, Ritwik, and Pal, Shovon
- Subjects
Condensed Matter - Materials Science ,Physics - Optics - Abstract
Understanding the complete light-spin interactions in magnetic systems is the key to manipulating the magnetization using optical means at ultrafast timescales. The selective addressing of spins by terahertz (THz) electromagnetic fields via Zeeman torque is, by far, one of the most successful ultrafast means of controlling magnetic excitations. Here we show that this traditional Zeeman torque on the spins is not sufficient, rather an additional relativistic field-derivative torque is essential to realize the observed magnetization dynamics. We accomplish this by exploring the ultrafast nonlinear magnetization dynamics of rare-earth, Bi-doped iron garnet when excited by two co-propagating THz pulses. By non-thermal optical pump-probe technique, we, first, find the collective exchange resonance mode between rare-earth and transition metal sublattices at 0.48 THz. We further explore the magnetization dynamics via a rather direct and efficient THz time-domain spectroscopic means. We find that the observed nonlinear trace of the magnetic response cannot be mapped to the magnetization precession induced by the Zeeman torque, while the Zeeman torque supplemented by an additional field-derivative torque follows the experimental evidences. This breakthrough not only enhances our comprehension of ultra-relativistic effects but also paves the way for the development of novel technologies harnessing light-induced control over magnetic systems., Comment: 5 figures
- Published
- 2024
39. Optimal Dispersion of Silent Robots in a Ring
- Author
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Das, Bibhuti, Gorain, Barun, Mondal, Kaushik, Mukhopadhyaya, Krishnendu, and Pandit, Supantha
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
Given a set of co-located mobile robots in an unknown anonymous graph, the robots must relocate themselves in distinct graph nodes to solve the dispersion problem. In this paper, we consider the dispersion problem for silent robots \cite{gorain2024collaborative}, i.e., no direct, explicit communication between any two robots placed in the nodes of an oriented $n$ node ring network. The robots operate in synchronous rounds. The dispersion problem for silent mobile robots has been studied in arbitrary graphs where the robots start from a single source. In this paper, we focus on the dispersion problem for silent mobile robots where robots can start from multiple sources. The robots have unique labels from a range $[0,\;L]$ for some positive integer $L$. Any two co-located robots do not have the information about the label of the other robot. The robots have weak multiplicity detection capability, which means they can determine if it is alone on a node. The robots are assumed to be able to identify an increase or decrease in the number of robots present on a node in a particular round. However, the robots can not get the exact number of increase or decrease in the number of robots. We have proposed a deterministic distributed algorithm that solves the dispersion of $k$ robots in an oriented ring in $O(\log L+k)$ synchronous rounds with $O(\log L)$ bits of memory for each robot. A lower bound $\Omega(\log L+k)$ on time for the dispersion of $k$ robots on a ring network is presented to establish the optimality of the proposed algorithm.
- Published
- 2024
40. Speed of sound and isothermal compressibility in a magnetized quark matter with anomalous magnetic moment of quarks
- Author
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Mondal, Rajkumar, Duari, Sourav, Chaudhuri, Nilanjan, Sarkar, Sourav, and Roy, Pradip
- Subjects
High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
We study the characteristics of quark matter under the influence of a background magnetic field with anomalous magnetic moment (AMM) of quarks at finite temperature and quark chemical potential in the framework of Polyakov loop extended Nambu Jona-Lasinio (PNJL) model. In presence of a magnetic field, the speed of sound and isothermal compressibility become anisotropic with respect to the direction of the background magnetic field, splitting into parallel and perpendicular directions with respect to the magnetic field. Though the qualitative nature of parallel and perpendicular components of squared speed of sound appear similar, they differ in magnitude at lower values of temperature. The parallel and perpendicular components of isothermal compressibility decrease with increasing temperature, indicating a trend towards increased incompressible strongly interacting matter. On inclusion of the AMM of quarks, the perpendicular component of isothermal compressibility becomes greater than the parallel component. Additionally, we investigate the quark number susceptibility normalized by its value at zero magnetic field, which may indicate the presence of magnetic fields in the system.
- Published
- 2024
41. Tunneling maps, non-monotonic resistivity, and non Drude optics in EuB$_6$
- Author
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Mondal, Tanmoy and Majumdar, Pinaki
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
For several decades the low carrier density local moment magnet EuB$_6$ has been considered a candidate material for ferromagnetic polarons. There is however no consistent explanation for the host of intriguing observations that have accrued over the years, including a prominently non-monotonic resistivity near $T_c$, and observation of spatial textures, with a characteristic spatial and energy scale, via scanning tunneling spectroscopy. We resolve all these features using a Heisenberg-Kondo lattice model for EuB$_6$, solved using exact diagonalisation based Langevin dynamics. Over a temperature window $\sim 0.7T_c - 1.5T_c$ we observe electronic and magnetic textures with the correct spatial and energy scale, and confirm an associated non-monotonic resistivity. We predict a distinctly `non Drude' optical conductivity in the polaronic phase, and propose a field-temperature phase diagram testable through spin resolved tunneling spectroscopy. We argue that the anomalous properties of EuB$_6$, and magnetic polaron materials in general, occur due to a non monotonic change in spatial character of `near Fermi level' eigenstates with temperature, and the appearance of a weak pseudogap near $T_c$., Comment: 6 pages, 4 figures
- Published
- 2024
42. AstroSat UV Deep Field South -- I. Far and Near-ultraviolet Source Catalog of the GOODS South region
- Author
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Saha, Kanak, Maulick, Soumil, Pandey, Pushpak, Bhattacharya, Souradeep, Borgohain, Anshuman, Mondal, Chayan, Rafelski, Marc, Kataria, Manish, Teplitz, Harry I., Tandon, Shyam N., Windhorst, Rogier A., Elmegreen, Bruce G., Herenz, Edmund Christian, and Rutkowski, Michael
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present the AstroSat UV Deep Field South (AUDFs), an imaging survey using the wide-field Ultraviolet Imaging Telescope on board AstroSat. AUDFs covers $\sim 236$ arcmin$^{2}$ of the sky area, including the Great Observatories Origins Deep Survey (GOODS) South field in F154W and N242W filters. The deep and shallow parts of AUDFs have exposure time $\sim 62000$ and $\sim31000$ sec respectively, in the F154W filter, while in the N242W filter, they are $\sim 64000$ and $\sim34000$ sec. These observations reached a $3\sigma$ depth of 27.2 and 27.7 AB mag with a $50\%$ completeness limit of 27 and 27.6 AB mag in the F154W and N242W filters, respectively. With the acquired depth, AUDFs is the deepest far and near-UV imaging data covering the largest area known to date at 1.2" - 1.6" spatial resolution. Two primary catalogs were constructed for the F154W and N242W filters, each containing 13495 and 19374 sources brighter than the 3$\sigma$ detection limit, respectively. Our galaxy counts power-law slope $\sim0.43$~dex~mag$^{-1}$ in the N242W filter matches well with HST/WFC3/UVIS observations. A wide range of extra-galactic science can be achieved with this unique data, such as providing a sample of galaxies emitting ionizing photons in the redshift range $z \sim 1 - 3$ and beyond; constraining the UV luminosity function, investigating the extended-UV (XUV) emission around star-forming galaxies and UV morphologies for $z < 1$. The UV catalog will enhance the legacy value of the existing optical/IR imaging and spectroscopic observations from ground and space-based telescopes on the GOODS South field., Comment: 26 pages, 19 figures, 7 tables, accepted for publication in the Astrophysical Journal Supplement Series, comments are welcome
- Published
- 2024
43. Nanoscale Engineering of Wurtzite Ferroelectrics: Unveiling Phase Transition and Ferroelectric Switching in ScAlN Nanowires
- Author
-
Wang, Ding, Wang, Ping, Mondal, Shubham, Hu, Mingtao, Wu, Yuanpeng, Wang, Danhao, Sun, Kai, and Mi, Zetian
- Subjects
Condensed Matter - Materials Science ,Physics - Applied Physics - Abstract
The pursuit of extreme device miniaturization and the exploration of novel physical phenomena have spurred significant interest in crystallographic phase control and ferroelectric switching in reduced dimensions. Recently, wurtzite ferroelectrics have emerged as a new class of functional materials, offering intriguing piezoelectric and ferroelectric properties, CMOS compatibility, and seamless integration with mainstream semiconductor technology. However, the exploration of crystallographic phase and ferroelectric switching in reduced dimensions, especially in nanostructures, has remained a largely uncharted territory. In this study, we present the first comprehensive investigation into the crystallographic phase transition of ScAlN nanowires across the full Sc compositional range. While a gradual transition from wurtzite to cubic phase was observed with increasing Sc composition, we further demonstrated that a highly ordered wurtzite phase ScAlN could be confined at the ScAlN/GaN interface for Sc contents surpassing what is possible in conventional films, holding great potential to addressing the fundamental high coercive field of wurtzite ferroelectrics. In addition, we provide the first evidence of ferroelectric switching in ScAlN nanowires, a result that holds significant implications for future device miniaturization. Our demonstration of tunable ferroelectric ScAlN nanowires opens new possibilities for nanoscale, domain, alloy, strain, and quantum engineering of wurtzite ferroelectrics, representing a significant stride towards the development of next-generation, miniaturized devices based on wurtzite ferroelectrics.
- Published
- 2024
44. DKL-KAN: Scalable Deep Kernel Learning using Kolmogorov-Arnold Networks
- Author
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Zinage, Shrenik, Mondal, Sudeepta, and Sarkar, Soumalya
- Subjects
Computer Science - Machine Learning ,Statistics - Machine Learning - Abstract
The need for scalable and expressive models in machine learning is paramount, particularly in applications requiring both structural depth and flexibility. Traditional deep learning methods, such as multilayer perceptrons (MLP), offer depth but lack ability to integrate structural characteristics of deep learning architectures with non-parametric flexibility of kernel methods. To address this, deep kernel learning (DKL) was introduced, where inputs to a base kernel are transformed using a deep learning architecture. These kernels can replace standard kernels, allowing both expressive power and scalability. The advent of Kolmogorov-Arnold Networks (KAN) has generated considerable attention and discussion among researchers in scientific domain. In this paper, we introduce a scalable deep kernel using KAN (DKL-KAN) as an effective alternative to DKL using MLP (DKL-MLP). Our approach involves simultaneously optimizing these kernel attributes using marginal likelihood within a Gaussian process framework. We analyze two variants of DKL-KAN for a fair comparison with DKL-MLP: one with same number of neurons and layers as DKL-MLP, and another with approximately same number of trainable parameters. To handle large datasets, we use kernel interpolation for scalable structured Gaussian processes (KISS-GP) for low-dimensional inputs and KISS-GP with product kernels for high-dimensional inputs. The efficacy of DKL-KAN is evaluated in terms of computational training time and test prediction accuracy across a wide range of applications. Additionally, the effectiveness of DKL-KAN is also examined in modeling discontinuities and accurately estimating prediction uncertainty. The results indicate that DKL-KAN outperforms DKL-MLP on datasets with a low number of observations. Conversely, DKL-MLP exhibits better scalability and higher test prediction accuracy on datasets with large number of observations.
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- 2024
45. Meson-nucleus bound states in quark meson coupling model
- Author
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Mondal, Arpita and Mishra, Amruta
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Nuclear Theory ,High Energy Physics - Phenomenology - Abstract
The formations of the $K(\bar{K})$, $D(\bar{D})$, and $B(\bar{B})$ meson-nucleus bound states in $^{16}O$, $^{40}Ca$, $^{90}Zr$, $^{197}Au$, and $^{208}Pb$ nucleus are investigated using the quark meson coupling model. The model relies on a mean field description of non-overlapping nucleon bags bound by the self-consistent interactions of scalar ($\sigma$, $\delta$) and vector ($\omega$, $\rho$) mesons with the (anti)quarks inside the bags, which is further extended to explore the properties of nuclei. We estimate the meson-nucleus bound state energies by solving the Klein-Gordon equations with the real potentials calculated self-consistently within the model, using a coordinate space approach. The calculations are carried out for different nuclear interactions. The effects of Coulomb interaction are considered in the present study for the charged mesons. Our study indicates the formation of rather deeply bound $B$-mesic states at the very central region of the nuclei, compared to the $D$ and $K$ mesons, offering a more promising probe to explore subtle nuclear medium effects. The investigations of such bound states are of particular interest for the upcoming $\rm{\bar{P}ANDA}$ at FAIR, J-PARC-E29 and JLab experiments., Comment: 29 pages, 5 tables, 6 figures
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- 2024
46. Look Hear: Gaze Prediction for Speech-directed Human Attention
- Author
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Mondal, Sounak, Ahn, Seoyoung, Yang, Zhibo, Balasubramanian, Niranjan, Samaras, Dimitris, Zelinsky, Gregory, and Hoai, Minh
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Computer Science - Computer Vision and Pattern Recognition - Abstract
For computer systems to effectively interact with humans using spoken language, they need to understand how the words being generated affect the users' moment-by-moment attention. Our study focuses on the incremental prediction of attention as a person is seeing an image and hearing a referring expression defining the object in the scene that should be fixated by gaze. To predict the gaze scanpaths in this incremental object referral task, we developed the Attention in Referral Transformer model or ART, which predicts the human fixations spurred by each word in a referring expression. ART uses a multimodal transformer encoder to jointly learn gaze behavior and its underlying grounding tasks, and an autoregressive transformer decoder to predict, for each word, a variable number of fixations based on fixation history. To train ART, we created RefCOCO-Gaze, a large-scale dataset of 19,738 human gaze scanpaths, corresponding to 2,094 unique image-expression pairs, from 220 participants performing our referral task. In our quantitative and qualitative analyses, ART not only outperforms existing methods in scanpath prediction, but also appears to capture several human attention patterns, such as waiting, scanning, and verification., Comment: Accepted for ECCV 2024
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- 2024
47. Certain Aspects of Deferred Statistical Convergence of Sequences in Probabilistic Normed Spaces
- Author
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Hossain, Nesar and Mondal, Rahul
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Mathematics - Functional Analysis ,40A35, 40G99, 54A20, 46A45 - Abstract
In this research article, we have primarily focused on the circumstantial investigation of deferred statistical convergence of sequences and investigated some fundamental results compatible with the structure of a probabilistic normed space. Additionally, the idea of deferred statistical Cauchy sequences has been discussed with reference to the structure of a probabilistic normed space., Comment: 12 pages
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- 2024
48. Ultrahigh pyroelectricity in monoelemental 2D tellurium
- Author
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Mishra, Hari Krishna, Jain, Ayushi, Saini, Dalip, Mondal, Bidya, Bera, Chandan, Ram, Shanker, and Mandal, Dipankar
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Condensed Matter - Materials Science ,Physics - Applied Physics - Abstract
We report an ultrahigh pyroelectric response in van der Waals bonded layers of two-dimensional (2D) tellurium (Te) nanosheets (thickness, d = 4 to 5 nm) at periodic on-off temperature oscillations. For the first time a large pyroelectric coefficient, Pc ~ 3 mC.m-2.K-1, is observed which is eightfold higher than the traditional state-of-the-art pyroelectrics (lead zirconate titanate, PZT). The first-principles calculations point out that the breakdown of centro-symmetry in the 1-3 Te-layers (P-3m1 space group) of a non-centrosymmetry (higher-order symmetry of C2 space group) on an angular twist in the Te-Te bonds of an exotic electronic state in 2D Te. The angular Te-Te twisting elicits a surface-enhanced Raman band at 101 cm-1 (absent in bulk Te). The stimulation of the Born effective charge, in-plane piezoelectricity and thermal expansion coefficient are shown to tailor the large pyroelectricity. Thus, 2D Te nanosheets present a new paradigm for the wide application of pyroelectric materials for developing thermal energy-based flexible electronics., Comment: Research Article
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- 2024
49. Determination of $|V_{ub}|$ from simultaneous measurements of untagged $B^0\to\pi^- \ell^+ \nu_{\ell}$ and $B^+\to\rho^0 \ell^+\nu_{\ell}$ decays
- Author
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Belle II Collaboration, Adachi, I., Aggarwal, L., Aihara, H., Akopov, N., Aloisio, A., Althubiti, N., Ky, N. Anh, Asner, D. M., Atmacan, H., Aushev, T., Aushev, V., Aversano, M., Ayad, R., Babu, V., Bae, H., Bahinipati, S., Bambade, P., Banerjee, Sw., Bansal, S., Barrett, M., Baudot, J., Bauer, M., Baur, A., Beaubien, A., Becherer, F., Becker, J., Bennett, J. V., Bernlochner, F. U., Bertacchi, V., Bertemes, M., Bertholet, E., Bessner, M., Bettarini, S., Bhuyan, B., Bianchi, F., Bierwirth, L., Bilka, T., Biswas, D., Bobrov, A., Bodrov, D., Bolz, A., Borah, J., Boschetti, A., Bozek, A., Bračko, M., Branchini, P., Briere, R. A., Browder, T. E., Budano, A., Bussino, S., Campagna, Q., Campajola, M., Cao, L., Casarosa, G., Cecchi, C., Cerasoli, J., Chang, M. -C., Chang, P., Cheaib, R., Cheema, P., Cheon, B. G., Chilikin, K., Chirapatpimol, K., Cho, H. -E., Cho, K., Cho, S. -J., Choi, S. -K., Choudhury, S., Corona, L., Cui, J. X., Dattola, F., De La Cruz-Burelo, E., De La Motte, S. A., De Nardo, G., De Nuccio, M., De Pietro, G., de Sangro, R., Destefanis, M., Dey, S., Dhamija, R., Di Canto, A., Di Capua, F., Dingfelder, J., Doležal, Z., Jiménez, I. Domínguez, Dong, T. V., Dorigo, M., Dorner, D., Dort, K., Dossett, D., Dreyer, S., Dubey, S., Dugic, K., Dujany, G., Ecker, P., Eliachevitch, M., Feichtinger, P., Ferber, T., Fillinger, T., Finck, C., Finocchiaro, G., Fodor, A., Forti, F., Frey, A., Fulsom, B. G., Gabrielli, A., Garcia-Hernandez, M., Garg, R., Gaudino, G., Gaur, V., Gaz, A., Gellrich, A., Ghevondyan, G., Ghosh, D., Ghumaryan, H., Giakoustidis, G., Giordano, R., Giri, A., Glazov, A., Gobbo, B., Godang, R., Gogota, O., Goldenzweig, P., Granderath, S., Greenwald, D., Gruberová, Z., Gu, T., Gudkova, K., Haide, I., Halder, S., Han, Y., Hara, T., Harris, C., Hayasaka, K., Hayashii, H., Hazra, S., Hearty, C., Hedges, M. T., Heidelbach, A., de la Cruz, I. Heredia, Villanueva, M. Hernández, Higuchi, T., Hoek, M., Hohmann, M., Horak, P., Hsu, C. -L., Humair, T., Iijima, T., Inami, K., Ipsita, N., Ishikawa, A., Itoh, R., Iwasaki, M., Jackson, P., Jacobs, W. W., Jang, E. -J., Jia, S., Jin, Y., Johnson, A., Joo, K. K., Junkerkalefeld, H., Kalita, D., Kaliyar, A. B., Kandra, J., Kang, K. H., Kang, S., Karyan, G., Kawasaki, T., Keil, F., Kiesling, C., Kim, C. -H., Kim, D. Y., Kim, K. -H., Kim, Y. -K., Kindo, H., Kinoshita, K., Kodyš, P., Koga, T., Kohani, S., Kojima, K., Konno, T., Korobov, A., Korpar, S., Kovalenko, E., Kowalewski, R., Križan, P., Krokovny, P., Kuhr, T., Kulii, Y., Kumar, J., Kumar, M., Kumar, R., Kumara, K., Kunigo, T., Kuzmin, A., Kwon, Y. -J., Lacaprara, S., Lalwani, K., Lam, T., Lanceri, L., Lange, J. S., Laurenza, M., Lautenbach, K., Leboucher, R., Diberder, F. R. Le, Lee, M. J., Leo, P., Lemettais, C., Levit, D., Lewis, P. M., Li, L. K., Li, S. X., Li, Y., Li, Y. B., Libby, J., Liptak, Z., Liu, M. H., Liu, Q. Y., Liu, Z. Q., Liventsev, D., Longo, S., Lueck, T., Lyu, C., Ma, Y., Maggiora, M., Maharana, S. P., Maiti, R., Maity, S., Mancinelli, G., Manfredi, R., Manoni, E., Mantovano, M., Marcantonio, D., Marcello, S., Marinas, C., Martellini, C., Martens, A., Martini, A., Martinov, T., Massaccesi, L., Masuda, M., Matvienko, D., Maurya, S. K., McKenna, J. A., Mehta, R., Meier, F., Merola, M., Metzner, F., Miller, C., Mirra, M., Mitra, S., Miyabayashi, K., Mizuk, R., Mohanty, G. B., Mondal, S., Moneta, S., Moser, H. -G., Mrvar, M., Mussa, R., Nakamura, I., Nakao, M., Nakazawa, Y., Charan, A. Narimani, Naruki, M., Narwal, D., Natkaniec, Z., Natochii, A., Nayak, L., Nayak, M., Nazaryan, G., Neu, M., Niiyama, M., Nishida, S., Ogawa, S., Onishchuk, Y., Ono, H., Pakhlova, G., Pardi, S., Parham, K., Park, H., Park, J., Park, S. -H., Paschen, B., Passeri, A., Patra, S., Paul, S., Pedlar, T. K., Peschke, R., Pestotnik, R., Piccolo, M., Piilonen, L. E., Angioni, G. Pinna, Podesta-Lerma, P. L. M., Podobnik, T., Pokharel, S., Praz, C., Prell, S., Prencipe, E., Prim, M. T., Prudiiev, I., Purwar, H., Rados, P., Raeuber, G., Raiz, S., Rauls, N., Reif, M., Reiter, S., Remnev, M., Reuter, L., Ripp-Baudot, I., Rizzo, G., Robertson, S. H., Roehrken, M., Roney, J. M., Rostomyan, A., Rout, N., Sanders, D. A., Sandilya, S., Santelj, L., Sato, Y., Savinov, V., Scavino, B., Schmitt, C., Schneider, S., Schnepf, M., Schwanda, C., Seino, Y., Selce, A., Senyo, K., Serrano, J., Sevior, M. E., Sfienti, C., Shan, W., Sharma, C., Shen, C. P., Shi, X. D., Shillington, T., Shimasaki, T., Shiu, J. -G., Shtol, D., Sibidanov, A., Simon, F., Singh, J. B., Skorupa, J., Sobie, R. J., Sobotzik, M., Soffer, A., Sokolov, A., Solovieva, E., Spataro, S., Spruck, B., Starič, M., Stavroulakis, P., Stefkova, S., Stroili, R., Sumihama, M., Sumisawa, K., Sutcliffe, W., Suwonjandee, N., Svidras, H., Takahashi, M., Takizawa, M., Tamponi, U., Tanaka, S., Tanida, K., Tenchini, F., Thaller, A., Tittel, O., Tiwary, R., Tonelli, D., Torassa, E., Trabelsi, K., Uchida, M., Ueda, I., Uglov, T., Unger, K., Unno, Y., Uno, K., Uno, S., Ushiroda, Y., Vahsen, S. E., van Tonder, R., Varvell, K. E., Veronesi, M., Vinokurova, A., Vismaya, V. S., Vitale, L., Vobbilisetti, V., Volpe, R., Vossen, A., Wach, B., Wakai, M., Wallner, S., Wang, E., Wang, M. -Z., Wang, Z., Warburton, A., Watanabe, M., Watanuki, S., Wessel, C., Won, E., Xu, X. P., Yabsley, B. D., Yamada, S., Yang, S. B., Yelton, J., Yin, J. H., Yook, Y. M., Yoshihara, K., Yuan, C. Z., Zani, L., Zeng, F., Zhang, B., Zhilich, V., Zhou, J. S., Zhou, Q. D., Zhou, X. Y., Zhukova, V. I., and Žlebčík, R.
- Subjects
High Energy Physics - Experiment - Abstract
We present a measurement of $|V_{ub}|$ from a simultaneous study of the charmless semileptonic decays $B^0\to\pi^- \ell^+ \nu_{\ell}$ and $B^+\to\rho^0 \ell^+\nu_{\ell}$, where $\ell = e, \mu$. This measurement uses a data sample of 387 million $B\overline{B}$ meson pairs recorded by the Belle~II detector at the SuperKEKB electron-positron collider between 2019 and 2022. The two decays are reconstructed without identifying the partner $B$ mesons. We simultaneously measure the differential branching fractions of $B^0\to\pi^- \ell^+ \nu_{\ell}$ and $B^+\to\rho^0 \ell^+\nu_{\ell}$ decays as functions of $q^2$ (momentum transfer squared). From these, we obtain total branching fractions $B(B^0\to\pi^- \ell^+ \nu_{\ell}) = (1.516 \pm 0.042 (\mathrm{stat}) \pm 0.059 (\mathrm{syst})) \times 10^{-4}$ and $B(B^+\to\rho^0 \ell^+\nu_{\ell}) = (1.625 \pm 0.079 (\mathrm{stat}) \pm 0.180 (\mathrm{syst})) \times 10^{-4}$. By fitting the measured $B^0\to\pi^- \ell^+ \nu_{\ell}$ partial branching fractions as functions of $q^2$, together with constraints on the non-perturbative hadronic contribution from lattice QCD calculations, we obtain $|V_{ub}|$ = $(3.93 \pm 0.09 \pm 0.13 \pm 0.19) \times 10^{-3}$. Here, the first uncertainty is statistical, the second is systematic, and the third is theoretical.
- Published
- 2024
50. Optical Micromanipulation of Soft Materials: Applications in Devices and Technologies
- Author
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Halder, Sanatan, Chanda, Debojit, Mondal, Dibyendu, Kundu, Sandip, and Khan, Manas
- Subjects
Condensed Matter - Soft Condensed Matter ,Physics - Applied Physics ,Physics - Optics - Abstract
Since its invention by Arthur Ashkin and colleagues at Bell Labs in the 1970s, optical micromanipulation, also known as optical tweezers or laser tweezers, has evolved remarkably to become one of the most convenient and versatile tools for studying soft materials, including biological systems. Arthur Ashkin received the Nobel Prize in Physics in 2018 for enabling these extraordinary scientific advancements. Essentially, a focused laser beam is used to apply and measure minuscule forces from a few piconewtons to femtonewtons by utilizing light-matter interaction at mesoscopic length scales. Combined with advanced microscopy and position-sensing techniques, optical micromanipulations enable us to investigate diverse aspects of functional soft materials. These include studying mechanical responses through force-elongation measurements, examining the structural properties of complex fluids employing microrheology, analyzing chemical compositions using spectroscopy, and sorting cells through single-cell analysis. Furthermore, it is utilized in various soft-matter-based devices, such as laser scissors and optical motors in microfluidic channels. This chapter presents an overview of optical micromanipulation techniques by describing fundamental theories and explaining the design considerations of conventional single-trap and dual-trap setups as well as recent improvisations. We further discuss their capabilities and applications in probing exotic soft-matter systems and in developing widely utilized devices and technologies based on functional soft materials., Comment: 73 pages, 13 figures
- Published
- 2024
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