Department of Physics

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In any natural science, measurements are the essential link between theory and observable reality. Is it possible to obtain accurate and relevant information via measurement whose action on the probed system is unknown? In other words, can one be convinced to know something about the nature without knowing in detail how the information was obtained? In this paper, we show that the answer is, surprisingly, yes. We construct and experimentally implement a quantum optical probing measurement where measurements on the probes, i.e., the photons' polarization states, are used to extract information on the systems, i.e., the frequency spectra of the same photons. Unlike the preexisting probing protocols, our measurement does not require any knowledge of the interaction between the probe and the system. © 2020 American Physical Society.

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Physical Review A

Experimental quantum probing measurements with no knowledge of the system-probe interaction

The ping-pong protocol adapted for quantum key distribution is studied in the trusted quantum noise scenario, wherein the legitimate parties can add noise locally. For a well-studied attack model, we show how non-unital, quantum non-Markovianity of the added noise can improve the key rate. We also point out that this noise-induced advantage cannot be obtained by Alice and Bob by adding local classical noise to their post-measurement data. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

Quantum Information Processing

Ping-pong quantum key distribution with trusted noise: non-Markovian advantage

We investigated the evolution of magnetic entropy in a triclinic FeVO4 multiferroic using temperature and magnetic field dependent magnetic measurements at magnetic transitions. The observed antiferromagnetic transitions are at TN1 = 22 K and TN2 = 15 K, together with the paramagnetic phase above TN1. A magnetic field induced maximum magnetic entropy change (ΔSM = 0.37 J kg−1K−1 at H = 50 kOe) at multiferroic transition, 15 K is observed in conjunction with a crossover from the negative to positive in ΔSM(T) data at TN1 towards TN2. The crossover of magnetic entropy substantiates the onset of inverse magnetocaloric effect below the antiferromagnetic transition temperature at TN1 together with maximum ΔSM at TN2. © 2020 Elsevier B.V.

Journal of Magnetism and Magnetic Materials

Onset of inverse magnetocaloric effect in multiferroic FeVO4 below the antiferromagnetic transition temperature TN1

We carried out temperature and magnetic field-dependent magnetic measurements to understand the evolution of magnetic non-collinearity near the antiferromagnetic phase transition in conjunction with the onset of significant change in magnetic entropy. We observed the maximum magnetic entropy change just before the magnetic ordering of Cr3+ in YCrO3 with the maximum change in magnetic entropy of ~ −0.38 Jkg−1K−1 at 8 T external field. Thought the magnetization is linear in higher fields (3 T–8 T), a significant deviation is observed in lower fields, substantiating the presence of weak ferromagnetism in YCrO3 with the antiferromagnetic ground state. © 2020 Elsevier Ltd

Vacuum

Magnetic entropy change in a non-collinear weak ferromagnetic YCrO3

We demonstrated ultrahigh sensitivity with excellent recovery time for H2S, NH3, NO2, and NO molecules on the sulfur and selenium surfaces of Janus WSSe monolayers using density functional theory. The selenium surface of the WSSe monolayer showed strong adsorption in comparison to the sulfur surface. The respective adsorption energies for H2S, NH3, NO2 and NO molecules are -0.193 eV, -0.220 eV, -0.276 eV, and -0.189 eV. These values are higher than the experimentally reported values for ultrahigh sensitivity gas sensors based on MoS2, MoSe2, WS2, and WSe2 monolayers. The computed adsorption energy and recovery time suggest that the desorption of gas molecules can be achieved easily in the WSSe monolayer. Further, the probable vacancy defects SV, SeV, and (S/Se)V and antisite defects SSe, and SeS are considered to understand their impact on the adsorption properties with respect to the pristine WSSe monolayer. We observed that the defect-including WSSe monolayers showed enhanced adsorption energy with fast recovery, which makes the Janus WSSe monolayer an excellent material for nanoscale gas sensors with ultrahigh sensitivity and excellent recovery time. This journal is © the Owner Societies.

Physical Chemistry Chemical Physics

Ultrahigh sensitivity with excellent recovery time for NH3and NO2in pristine and defect mediated Janus WSSe monolayers

Biomaterials are primarily insulators. For nearly a century, electromagnetic resonance and antenna–receiver properties have been measured and extensively theoretically modeled. The dielectric constituents of biomaterials—if arranged in distinct symmetries, then each vibrational symmetry—would lead to a distinct resonance frequency. While the literature is rich with data on the dielectric resonance of proteins, scale-free relationships of vibrational modes are scarce. Here, we report a self-similar triplet of triplet resonance frequency pattern for the four-4 nm-wide tubulin protein, for the 25-nm-wide microtubule nanowire and 1-µm-wide axon initial segment of a neuron. Thus, preserving the symmetry of vibrations was a fundamental integration feature of the three materials. There was no self-similarity in the physical appearance: the size varied by 106 orders, yet, when they vibrated, the ratios of the frequencies changed in such a way that each of the three resonance frequency bands held three more bands inside (triplet of triplet). This suggests that instead of symmetry, self-similarity lies in the principles of symmetry-breaking. This is why three elements, a protein, it’s complex and neuron resonated in 106 orders of different time domains, yet their vibrational frequencies grouped similarly. Our work supports already-existing hypotheses for the scale-free information integration in the brain from molecular scale to the cognition. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

Fractal and Fractional

Fractal, scale free electromagnetic resonance of a single brain extracted microtubule nanowire, a single tubulin protein and a single neuron

In the past thirty years, scientists have put enormous efforts into developing smart materials with multiple functionalities. Among such existing intelligent materials, electrochromic and non-volatile memory materials synthesized via organic–metallic hybrid polymers have shown their remarkable presence. To date, a wide variety of transition metal ions have been adopted for forming these polymers. However, reports on the use of lanthanide metal ion for observing such smart behaviour are uncommon. Therefore, the present report focuses on synthesizing a novel Eu(III) metal ion-based organic–metallic hybrid polymer for observing the smart properties using previously reported Schiff’s base polydentate organic ligand. Further, its different possible coordination modes with the ligand have been discussed. The structure of the polymer has been fully supported by Nuclear Magnetic Resonance and Ultraviolet–visible titration. Along with this, the reversible redox properties of this polymer have also been established along with the study of their spectroelectrochemical properties between yellow and bleached colour. The Resistive Random Access Memory properties of this polymer have been observed by spin coating polymer on Indium Tin Oxide coated substrate for fabricating a Metal–Insulator–Metal structure. The bipolar Current–Voltage (I–V) characteristics of this polymer in both the biasing directions have been observed, with the repeatability of about 1000 cycles for Write-Read-Erase-Read operation. The retention capability of this polymer has also been established for 2000 pulses. Thus, the current work presents fascinating aspects of using a lanthanide metal ion collectively for studying both the redox-active properties, i.e. electrochromic and non-volatile memristive properties. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Materials Science: Materials in Electronics

Electrochromic and bipolar memory switching properties of novel Eu(III)-polymer of multidentate Schiff’s base ligand

The recovery and recrystallization kinetics of 80% cold rolled ultra low carbon steel are investigated during isothermally annealing for temperature ranges 350-640 °C as a function of different annealing time. The recovery is assessed by magnetic coercivity (Hc), while the recrystallization is determined by mechanical hardness. At low temperature (350 to 520 °C) annealing, recovery dominates for long time (∼12 000 s), while the annealing at 550 °C/ 900s and 580 °C/ 300s causes the recrystallized nuclei formation . The recovery kinetics is introduced by differential rate equation, explaining the reduction in coercivity with the recovery progress and the variation of an activation energy from 41-113 kJ mol-1. The recrystallization kinetics is found faster at high annealing temperature 640 °C than 550 and 580 °C based on hardness measurement, justifying by apparent activation energy within 114-190 kJ mol-1. Furthermore, the recovery and recrystallization rate increase with different annealing time, consistent to the change of microstructures and grain boundary characteristics evaluated by the orientation imaging microscopy (OIM) of electron backscattered diffraction (EBSD). © 2020 The Author(s). Published by IOP Publishing Ltd.

Materials Research Express

Microstructural evolution, recovery and recrystallization kinetics of isothermally annealed ultra low carbon steel

The present work is focused on the effect of annealing on the magnetic, microstructure, and mechanical properties of 50% cold-rolled IF steel. The heat treatment is carried out at different temperatures ranging from 200 to 700 °C for 15 min holding time, to monitor the recovery and recrystallization process. The microstructure is observed by optical microscopy, and analyzed by image analysis software for quantification of recrystallization fractions and grain size. At 200–550 °C temperatures, no significant microstructural change is observed, indicating the dominancy of recovery at these temperatures. It is also confirmed by a nominal variation of hardness and tensile properties at the aforementioned temperature ranges. The magnetic parameters of coercivity (Hc) and remanent (Br) are measured through the electromagnetic sensing device, indicating a significant change during recovery. The recrystallization completion takes place at 660 °C, confirmed by mechanical and magnetic softening. © 2020, Springer Nature Singapore Pte Ltd.

Lecture Notes in Mechanical Engineering

Microstructure, Mechanical, and Magnetic Properties of Cold-Rolled Low-Carbon IF Steel

The investigation addresses the impact of stress on soft magnetic and giant magneto-impedance (GMI) of rapidly quenched Fe77.5Si7.5B15, (Co94Fe6)72.5Si12.5B15 and (Co94Fe6)72.5Si12.5B12.5Nb0.5Cr2 microwires. Differential scanning calorimetry revealed interesting phase stability in the later alloys. The vitrified microwires contained dominant Co and a lean Fe content showed much superior soft magnetic properties and high magnetoimpedance. The alloy microwires incorporated with Nb and Cr manifested lowest coercivity value of 0.034 Oe with a high GMImax value of 425% in the as-quenched state. The uniaxial stress applied on the microwires modified the shape of the hysteresis loops and GMI plots. The hysteresis loops showed stress dependence of coercivity based on alloy chemistry, phase stability and consequent magnetostriction. The GMImax revealed sensitive change with respect to the applied stress in all the alloy microwires. In addition to GMImax interesting features were observed in the GMI profile pertaining influence of stress on the anisotropy field. The anisotropy field shifted systematically in one of the alloy microwires which displayed symmetric dual GMI peaks. The stress was also found to modify the asymmetric characteristics in a microwire. © 2020 Elsevier B.V.