arXiv subjects

R. Hussain

Publications and source records attributed to R. Hussain.

4 recordsLinked to original sources

arXiv2026

Synchronization of Bloch Oscillations in array of parallel Josephson Junctions

We demonstrate the synchronization of current quantization in a parallel array of weakly coupled Josephson Junctions operating in the regime of the coherent quantum phase slip. The first quantized current step on the voltage-current characteristic of 69 parallel Josephson junctions, under microwave excitation at a frequency of f = 19.325 GHz, is observed at 426 nA. Experiments show that accuracy of quantization does not degrade with increasing number of combined Josephson junctions. This demonstration addresses the issue of quantized current amplitude requirements adopted for a practical quantum standard, while leaving the question of accuracy for further research. At present, the quantum current standard of accepted metrological accuracy in the triangle of electrical units is under development. The other two, the Volt and Ohm standards based on the Josephson and Quantum Hall effects, respectively, are already well established in metrology.

cond-mat.supr-con↗

arXiv2021

Explainable Artificial Intelligence (XAI): An Engineering Perspective

The remarkable advancements in Deep Learning (DL) algorithms have fueled enthusiasm for using Artificial Intelligence (AI) technologies in almost every domain; however, the opaqueness of these algorithms put a question mark on their applications in safety-critical systems. In this regard, the `explainability' dimension is not only essential to both explain the inner workings of black-box algorithms, but it also adds accountability and transparency dimensions that are of prime importance for regulators, consumers, and service providers. eXplainable Artificial Intelligence (XAI) is the set of techniques and methods to convert the so-called black-box AI algorithms to white-box algorithms, where the results achieved by these algorithms and the variables, parameters, and steps taken by the algorithm to reach the obtained results, are transparent and explainable. To complement the existing literature on XAI, in this paper, we take an `engineering' approach to illustrate the concepts of XAI. We discuss the stakeholders in XAI and describe the mathematical contours of XAI from engineering perspective. Then we take the autonomous car as a use-case and discuss the applications of XAI for its different components such as object detection, perception, control, action decision, and so on. This work is an exploratory study to identify new avenues of research in the field of XAI.

cs.LG↗

arXiv2019

Mixed magnetism, nanoscale electronic segregation and ubiquitous first order transitions in giant magnetocaloric MnFeSiP alloys detected by $^{55}$Mn NMR

We report on a study on a representative set of Fe$_{2}$P-based MnFePSi samples by means of $^{55}$Mn NMR in both zero and applied magnetic field. The first-order nature of the magnetic transition is demonstrated by truncated order parameter curves with a large value of the local ordered moment at the Curie point, even at compositions where the transition appears second order from magnetic measurements. No weak ferromagnetic order could be detected at Si-poor compositions showing the kinetic arrest phenomenon, but rather the phase separation of fully ferromagnetic domains from volume fractions where Mn spins are fluctuating. The more pronounced decrease of the ordered moment at the $3f$ sites on approaching $T_C$, characteristic of the mixed magnetism of these materials, is demonstrated to be driven by a vanishing spin density rather than enhanced spin fluctuations at the $3f$ site. An upper limit of 0.03~$μ_B$ is set for the fluctuating Mn moment at the $3f$ site by the direct detection of a $^{55}$Mn NMR resonance peak in the Mn-rich samples above $T_C$, showing nearly temperature-independent frequency shifts. A sharper secondary peak observed at the same compositions reveals however the disproportionation of a significant $3f$-Mn fraction with negligible hyperfine couplings, which retains its diamagnetic character across the transition, down to the lowest available temperatures. Such a diamagnetic fraction qualitatively accounts for the reduced average $3f$ moment previously reported at large Mn concentrations.

cond-mat.str-el↗

arXiv2016

Plasmon drag effect in profile-modulated gold films. Theory and experiment

Plasmon drag effect is studied theoretically and experimentally in gold films with a sine-wave height profile. Numerical simulations based on the modified electromagnetic momentum loss approach are shown to correctly describe the photoinduced voltage associated with propagating surface plasmon polaritons. Direct proportionality of energy and momentum transfer in interactions of plasmons and free electrons in metal is proven to be valid for surfaces with relatively low height modulation amplitudes. The effect is also discussed in frames of an equivalent circuit model, which can provide qualitative description for surfaces with random roughness.

cond-mat.mtrl-sci↗