arXiv subjects

Waqas Ahmed

Publications and source records attributed to Waqas Ahmed.

At least 37 records · Page 2Linked to original sources

arXiv2026

SARS: A Novel Face and Body Shape and Appearance Aware 3D Reconstruction System extends Morphable Models

Morphable Models (3DMMs) are a type of morphable model that takes 2D images as inputs and recreates the structure and physical appearance of 3D objects, especially human faces and bodies. 3DMM combines identity and expression blendshapes with a basic face mesh to create a detailed 3D model. The variability in the 3D Morphable models can be controlled by tuning diverse parameters. They are high-level image descriptors, such as shape, texture, illumination, and camera parameters. Previous research in 3D human reconstruction concentrated solely on global face structure or geometry, ignoring face semantic features such as age, gender, and facial landmarks characterizing facial boundaries, curves, dips, and wrinkles. In order to accommodate changes in these high-level facial characteristics, this work introduces a shape and appearance-aware 3D reconstruction system (named SARS by us), a c modular pipeline that extracts body and face information from a single image to properly rebuild the 3D model of the human full body.

cs.CV↗

arXiv2026

Warm Hybrid Axion Inflation in $α$-Attractor Models Constrained by ACT and Future Plan experiments

We present a comprehensive study of warm hybrid inflation within the framework of $α$-attractor models, where an axionic inflaton is coupled to a waterfall field in the presence of thermal dissipation. The model is analyzed for both linear ($Υ\propto T$) and cubic ($Υ\propto T^{3}$) dissipation regimes. Confronting the theoretical predictions with the latest observational data from Planck+BICEP/Keck, P-ACT-LB-BK18 and SPT, and , we find that in the weak dissipative regime ($Q_{*} \lesssim 10^{-5}$), the scalar spectral index $n_{s} \simeq 0.965$ lies at the boundary of the combined P-ACT-LB-BK18 constraints, while the tensor-to-scalar ratio $r$ remains within observable ranges. For stronger dissipation ($Q_{*} \gtrsim 10^{-5}$), the model predicts values of $n_{s}$ well within the $1$--$2σ$ confidence region of all datasets, with tensor modes remaining fully observable in both dissipation scenarios. These results indicate that forthcoming CMB polarization experiments may be capable of detecting primordial gravitational waves, thereby providing a robust observational test of warm hybrid inflation across different dissipative regimes.

hep-ph↗

arXiv2026

Quantum AI for Cybersecurity: A hybrid Quantum-Classical models for attack path analysis

Modern cyberattacks are increasingly complex, posing significant challenges to classical machine learning methods, particularly when labeled data is limited and feature interactions are highly non-linear. In this study we investigates the potential of hybrid quantum-classical learning to enhance feature representations for intrusion detection and explore possible quantum advantages in cybersecurity analytics. Using the UNSW-NB15 dataset, network traffic is transformed into structured feature vectors through classical preprocessing and normalization. Classical models, including Logistic Regression and Support Vector Machines with linear and RBF kernels, are evaluated on the full dataset to establish baseline performance under large-sample conditions. Simultaneously, a quantum-enhanced pipeline maps classical features into variational quantum circuits via angle encoding and entangling layers, executed on a CPU-based quantum simulator, with resulting quantum embeddings classified using a classical SVM. Experiments show that while classical models achieve higher overall accuracy with large datasets, quantum-enhanced representations demonstrate superior attack recall and improved class separability when data is scarce, suggesting that quantum feature spaces capture complex correlations inaccessible to shallow classical models. These results highlight the potential of quantum embeddings to improve generalization and representation quality in cybersecurity tasks and provide a reproducible framework for evaluating quantum advantages as quantum hardware and simulators continue to advance.

cs.CR↗

arXiv2026

Learning to be Reproducible: Custom Loss Design for Robust Neural Networks

To enhance the reproducibility and reliability of deep learning models, we address a critical gap in current training methodologies: the lack of mechanisms that ensure consistent and robust performance across runs. Our empirical analysis reveals that even under controlled initialization and training conditions, the accuracy of the model can exhibit significant variability. To address this issue, we propose a Custom Loss Function (CLF) that reduces the sensitivity of training outcomes to stochastic factors such as weight initialization and data shuffling. By fine-tuning its parameters, CLF explicitly balances predictive accuracy with training stability, leading to more consistent and reliable model performance. Extensive experiments across diverse architectures for both image classification and time series forecasting demonstrate that our approach significantly improves training robustness without sacrificing predictive performance. These results establish CLF as an effective and efficient strategy for developing more stable, reliable and trustworthy neural networks.

cs.LG↗

arXiv2025

Hybrid Ensemble Method for Detecting Cyber-Attacks in Water Distribution Systems Using the BATADAL Dataset

The cybersecurity of Industrial Control Systems that manage critical infrastructure such as Water Distribution Systems has become increasingly important as digital connectivity expands. BATADAL benchmark data is a good source of testing intrusion detection techniques, but it presents several important problems, such as imbalance in the number of classes, multivariate time dependence, and stealthy attacks. We consider a hybrid ensemble learning model that will enhance the detection ability of cyber-attacks in WDS by using the complementary capabilities of machine learning and deep learning models. Three base learners, namely, Random Forest , eXtreme Gradient Boosting , and Long Short-Term Memory network, have been strictly compared and seven ensemble types using simple averaged and stacked learning with a logistic regression meta-learner. Random Forest analysis identified top predictors turned into temporal and statistical features, and Synthetic Minority Oversampling Technique (SMOTE) was used to overcome the class imbalance issue. The analyics indicates that the single Long Short-Term Memory network model is of poor performance (F1 = 0.000, AUC = 0.4460), but tree-based models, especially eXtreme Gradient Boosting, perform well (F1 = 0.7470, AUC=0.9684). The hybrid stacked ensemble of Random Forest , eXtreme Gradient Boosting , and Long Short-Term Memory network scored the highest, with the attack class of 0.7205 with an F1-score and a AUC of 0.9826 indicating that the heterogeneous stacking between model precision and generalization can work. The proposed framework establishes a robust and scalable solution for cyber-attack detection in time-dependent industrial systems, integrating temporal learning and ensemble diversity to support the secure operation of critical infrastructure.

cs.CR↗

arXiv2025

Response of Elliptical Scatterer Due to Perfect Magnetic Material

The effects on the bistatic echo width of an elliptical cylinder due to a perfect magnetic material are reported in this article. The configuration is analyzed using the separation of variables method and Mathieu functions. In this approach, the structural geometry is illuminated by an electromagnetic field. Radial and angular Mathieu functions have been used in the formulation. Notably, the maxima of the scattered elliptic transfer electric mode ($θ= 180^{\circ}$) are much higher than those of the scattered transfer magnetic mode, comparable to terms $θ= 120^{\circ}$ and $θ= 240^{\circ}$, respectively. It can be observed that an increase in the in-plane radial component leads to the linearity principle for the transfer electric mode, while non-linear behavior is investigated for the elliptic transfer magnetic mode. Therefore, the unidirectional bistatic echo width is subject to non-directional behavior. These analogous results may have applications in the fields of optics, meteorology, acoustics, radio astronomy, collision physics, and other disciplines where wave scattering phenomena play a crucial role. Furthermore, the findings of this study contribute to the fundamental understanding of electromagnetic interactions with complex geometries and materials

physics.app-ph↗

arXiv2025

Primordial Black Holes and Second-order Gravitational Waves in Axion-like Hybrid Inflation

We investigate the possibility that primordial black holes (PBHs) can be formed from large curvature perturbations generated during the waterfall phase transition in a hybrid inflation model driven by an axion-like particle (ALP) $ϕ$. The model predicts a spectral index $n_s \simeq 0.964$ and a tensor-to-scalar ratio $r \simeq 0.003$, in agreement with Planck data and potentially testable by next generation cosmic microwave background (CMB) experiments such as CMB-S4 and LiteBIRD. We find that the PBH mass and the peak of the associated scalar-induced gravitational wave (SIGW) spectrum are correlated with the ALP mass. In particular, PBHs in the mass range $10^{-13}\, M_\odot$ can constitute either the entire dark matter (DM) content of the universe or a significant fraction of it. The predicted second-order GWs from this mechanism are within the sensitivity reach of future observatories like LISA and ET. The typical reheating temperature in the model is around $10^6 - 10^7$ GeV is consistent with Big Bang Nucleosynthesis (BBN) constraints.

astro-ph.CO↗

arXiv2025

Tribrid Inflation, Type II Leptogenesis, and Observable Gravitational Waves in $SU(3)_c \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$

We present a concrete realization of tribrid inflation within the framework of the gauge group $SU(3)_c \times SU(2)_L \times SU(2)_R \times U(1)_{B-L}$. In this model, inflation is driven by the neutral components of left-handed Higgs triplets, which also play a central role in generating the observed baryon asymmetry of the universe via non-thermal leptogenesis. Tiny neutrino masses arise naturally through a type-II seesaw mechanism, facilitated by right-handed triplet fields. Supergravity corrections, stemming from the leading-order terms in a non-minimal Kähler potential, are essential in bringing the predictions of the scalar spectral index $n_s$ into agreement with the latest cosmological data, including the Atacama Cosmology Telescope Data Release 6, Planck 2018, and LB-BK18. A key feature of this model is the existence of a viable parameter space that predicts potentially observable primordial gravitational waves, with a tensor-to-scalar ratio $r \lesssim 0.005$, placing it within reach of upcoming experiments.

hep-ph↗

arXiv2025

Radiatively Corrected Starobinsky Inflation and Primordial Gravitational Waves in Light of ACT Observations

Nonminimal coupling between the inflaton and the Ricci scalar plays a crucial role in shaping the predictions of single-field inflationary models. While a quartic potential with such coupling represents one of the simplest realizations compatible with cosmological observations, it generically receives important radiative corrections when the inflaton interacts with other fields, particularly those involved in the reheating process. In this work, we focus on radiative corrections arising from bosonic scalar couplings and study their impact on inflationary dynamics within the nonminimally coupled quartic potential framework. We demonstrate that bosonic corrections, unlike fermionic ones, yield predictions more compatible with the latest constraints from the Atacama Cosmology Telescope (ACT) Data Release 6, especially when combined with Planck and BICEP/Keck data. We begin with a general model involving a gauge-singlet real scalar inflaton coupled to a complex scalar field, which could be the Standard Model Higgs or a GUT Higgs. As a concrete realization, we also investigate the case where the inflaton serves as a dark matter candidate through a Higgs portal interaction while highlighting its potential to generate observable levels of primordial gravitational waves. Notably, the nonminimally coupled inflation model studied here is field-theoretically equivalent to the Starobinsky model, and the inclusion of quantum corrections from scalar fields leads to characteristic imprints in the $(n_s, r)$ plane, allowing for refined constraints on scalar couplings from current and future observations.

astro-ph.CO↗

arXiv2025

The Light Neutralino Dark Matter in the Generalized Minimal Supergravity (GmSUGRA)

We investigate both the $Z$ and $H$ poles solutions for the Higgsino mass parameter $μ>0$ and $μ<0$ for the neutralino dark matter in light of the LHC supersymmetry searches and the direct detection dark matter experiments, LUX-ZEPLIN (LZ), in the Generalized Minimal Supergravity (GmSUGRA). Our study indicates that the latest experimental constraints from the LHC and LZ Collaborations exclude the light Higgsinos in the $Z$ and $H$ pole regions for the $μ>0$ case. Interestingly, for the $μ< 0$ case, a very light Higgsinos can still be consistent with the current constraints from the electroweakino searches and LZ experiment in the $Z$ and $H$ poles. Consequently, the $μ< 0$ case appears more promising and thus requires the dedicated efforts to make definitive conclusions about their current status from the experimental Collaborations. In this framework, our findings indicate a deviation of up to $2σ$ from the central value of $ a_μ\equiv (g-2)_μ/2 $, resonating with the experimental results reported by CMD and BDM.

hep-ph↗

arXiv2024

Hybrid Inflation, Reheating and Dark Radiation in a IIB perturbative moduli stabilization scenario

We study the cosmological implications of an effective field theory model derived within a configuration of D7 brane stacks in the framework of type-IIB string theory. We consider a suitable geometric setup where the Kähler moduli fields are stabilized and the parametric space is constrained so that a de Sitter vacuum is ensured. In addition to the moduli fields we also take into account the usual Higgs and matter fields included in the effective field theory. In this background, we implement the standard hybrid inflation scenario with a singlet scalar field acting as the inflaton and the Higgs states serving as waterfall fields. Radiative corrections and soft supersymmetry breaking terms play an essential role in the realization of a successful inflationary scenario consistent with the present cosmological data. Small tensor-to-scalar ratio values are predicted, which can be probed in future planned experiments. Further constraints on the model's parameters are derived from bounds on dark radiation which is measured as a contribution to the effective number of neutrino species $N_{\rm eff}$. In particular, we find an excess of $ΔN_{\rm eff}\leq{0.95}$ at $2σ$ confidence level with natural values of the involved couplings.

hep-ph↗

arXiv2024

Evaluating the method reproducibility of deep learning models in the biodiversity domain

Artificial Intelligence (AI) is revolutionizing biodiversity research by enabling advanced data analysis, species identification, and habitats monitoring, thereby enhancing conservation efforts. Ensuring reproducibility in AI-driven biodiversity research is crucial for fostering transparency, verifying results, and promoting the credibility of ecological findings.This study investigates the reproducibility of deep learning (DL) methods within the biodiversity domain. We design a methodology for evaluating the reproducibility of biodiversity-related publications that employ DL techniques across three stages. We define ten variables essential for method reproducibility, divided into four categories: resource requirements, methodological information, uncontrolled randomness, and statistical considerations. These categories subsequently serve as the basis for defining different levels of reproducibility. We manually extract the availability of these variables from a curated dataset comprising 61 publications identified using the keywords provided by biodiversity experts. Our study shows that the dataset is shared in 47% of the publications; however, a significant number of the publications lack comprehensive information on deep learning methods, including details regarding randomness.

cs.IR↗

arXiv2024

Inflation, Proton Decay and Gravitational Waves from Metastable Strings in $SU(4)_C \times SU(2)_L \times U(1)_R$ Model

We present a realistic supersymmetric $μ$-hybrid inflation model within the framework of $SU(4)_C \times SU(2)_L \times U(1)_R$ gauge symmetry, wherein the symmetry breaking $SU(4)_C \times SU(2)_L \times U(1)_R\rightarrow SU(3)_C\times SU(2)_L \times U(1)_{B-L}\times U(1)_R$ occurs before observable inflation, effectively eliminating topologically stable primordial monopoles. Subsequent breaking of $U(1)_{B-L} \times U(1)_R \rightarrow U(1)_Y$ after inflation leads to the formation of superheavy metastable cosmic strings (CSs), capable of producing a stochastic gravitational wave background (SGWB) consistent with the recent PTA data. Moreover, the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$ align with Planck 2018 observations. A consistent scenario for reheating and non-thermal leptogenesis is employed to explain the observed matter content of the universe. Finally, the embedding of $G_{421}$ into the Pati-Salam gauge symmetry $G_{422}$ is briefly discussed, predicting potentially observable proton decay rates detectable at facilities such as Hyper Kamiokande and DUNE.

hep-ph↗

arXiv2024

Supersymmetric Hybrid Inflation in Light of CMB Experiments and Swampland Conjectures

This study revisits supersymmetric (SUSY) hybrid inflation in light of CMB experiments and swampland conjectures. We first show that if one adds radiative, soft mass, and SUGRA corrections to the scalar potential, supersymmetric hybrid inflation is still consistent with Planck 2018 despite an impression that it does not. Usually, in SUSY hybrid inflation with minimal Kähler potential, the gauge symmetry breaking scale $M$ turns out to be ${\cal O}(10^{15})$ GeV, which causes proton decay rate problem. In this study, we present a new parameter space where the proton decay rate problem can be avoided by achieving $M$ of the order of $10^{16}$ GeV with $M_{S}^{2}<$0 and $am_{3/2}>$0. In this scenario, one requires a soft SUSY breaking scale $|M_{S}| \gtrsim 10^{6}$ GeV. Moreover, the tensor to scalar ratio $r$ is in the range $10^{-16}$ to $10^{-6}$, which is quite small. In this case, modified swampland hold, but it is difficult to satisfy trans-Planckian censorship conjecture. For this reason, we also consider non-minimal Kähler potential. We fixed spectral index $n_{S}=$0.9665 (central value) of Planck 2018 data and $M=2\times 10^{16}$ GeV and present our calculations. We show the canonical measure of primordial gravity waves $r$ for $M_{S}=$ 1 TeV, $m_{3/2}=$ 1 TeV, $κ_{S}<0$ for $\cal{N}=$1 and $\cal{N}=$2, ranges from $10^{-5}$ to $0.01$ which can be observed in Planck and next-generation experiments such as LiteBIRD, Simons Observatory, PRISM, PIXIE,CORE, CMB-S4 and CMB-HD experiments that are gearing up to measure it. In addition to it, we present the parametric space and benchmark points for a non-minimal case which is consistent with modified swampland and trans-Planckian censorship conjectures.

hep-ph↗

arXiv2023

The Right-Handed Slepton Bulk Regions for Dark Matter in the Generalized Minimal Supergravity (GmSUGRA)

We study the light right-handed slepton bulk regions for dark matter from the Generalized Minimal Supergravity (GmSUGRA) in the Minimal Supersymmetric Standard Model (MSSM). In our comprehensive numerical studies, we show that $\mathcal{R_{\tildeϕ}}\gtrsim10\%$ is a conservative criteria to formulate bulk region, where $\mathcal{R_{\tildeϕ}}\equiv({m_{\tildeϕ}-m_{\tildeχ_1^0}})/{m_{\tildeχ_1^0}}$. For right-handed stau as the Next to the Lightest Supersymmetric Partcile (NLSP), we find a large viable parameter space, consistent with the current LHC constraints, Planck2018 dark matter relic density bounds, and direct bounds on neutralino-nucleons scattering cross-section that naturally supports the right-handed stau bulk regions for dark matter. In particular, the upper bounds on the masses of the Lightest Supersymmetric Particle (LSP) neutralino and right-handed stau are about 120.4 GeV and 138 GeV, respectively. This bulk region may be beyond the current LHC reach and could be probed at LUX-ZEPLIN, a next-generation dark matter direct detection experiment, the Future Circular Collider (FCC-ee) at CERN, and the Circular Electron Positron Collider (CEPC). However, the scenario with the right-handed selectron as the NLSP is excluded by the LHC supersymmetry searches.

hep-ph↗

arXiv2023

Revisit a realistic intersecting D6-brane with modified soft SUSY terms

Because there are a few typos in the supersymmetry breaking sfermion masses and trilinear soft term, regarding the current Large Hadron Collider (LHC) and dark matter searches, we revisit a three-family Pati-Salam model based on intersecting D6-branes in Type IIA string theory on a $\mathbf{T^6/(\Z_2\times \Z_2)}$ orientifold with a realistic phenomenology. We study the viable parameter space and discuss the spectrum consistent with the current LHC Supersymmetry searches along with the dark matter relic density bounds from the Planck 2018 data. For the gluinos and first two generations of sfermions, we observe that the gluino mass is in the range [2, 14] TeV, the squarks mass range is [2, 13] TeV and the sleptons mass is in the range [1, 5] TeV. We achieve the cold dark matter relic density consistent with 5$σ$ Planck 2018 bounds via A-funnel and coannihilation channels such as stop-neutralino, stau-neutralino, and chargino-neutralino. Except for a few chargino-neutralino coannihilation solutions, these solutions also satisfy current nucleon-neutralino spin-independent and spin-dependent scattering cross-sections and may be probed by future dark matter searches.

hep-ph↗

arXiv2023

Gravitational waves from metastable cosmic strings in Pati-Salam model in light of new pulsar timing array data

A series of pulsar timing arrays (PTAs) recently observed gravitational waves at the nanohertz frequencies. Motivated by this remarkable result, we present a novel class of Pati-Salam models that give rise to a network of metastable cosmic strings, offering a plausible explanation for the observed PTA data. Besides, we introduce a hybrid inflationary scenario to eliminate magnetic monopoles that arise during the spontaneous symmetry breaking of the Pati-Salam gauge group to the Standard Model. The resulting scalar spectral index is compatible with Planck data, and the tensor-to-scalar ratio is anticipated to be extremely small. Moreover, we incorporate a non-thermal leptogenesis to generate the required baryon asymmetry in our framework. Finally, the gravitational wave spectra generated by the metastable cosmic strings not only correspond to signals observed in recent PTAs, including NANOGrav, but are also within the exploration capacity of both present and future ground-based and space-based experiments.

hep-ph↗

arXiv2023

Probing Stochastic Gravitational Wave Background from $SU(5) \times U(1)_χ$ Strings in Light of NANOGrav 15-Year Data

A realistic model of $SU(5) \times U(1)_χ$, embedded in $SO(10)$ supersymmetric grand unified theory, is investigated for the emergence of a metastable cosmic string network. This network eventually decays via the Schwinger production of monopole-antimonopole pairs, subsequently generating a stochastic gravitational wave background that is compatible with the NANOGrav 15-year data. In order to avoid the monopole problem in the breaking of both $SO(10)$ and $SU(5)$, a non-minimal Higgs inflation scenario is incorporated. The radiative breaking of the $U(1)_χ$ symmetry at a slightly lower scale plays a pivotal role in aligning the string tension parameter with the observable range. The resultant gravitational wave spectrum not only accounts for the signal observed in the most recent pulsar timing array (PTA) experiments but is also accessible to both current and future ground-based and space-based experiments.

hep-ph↗