Department of Physics

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

The implementation of exceptional points (EPs), a special type of topological singularities, has emerged as a new paradigm for engineering the quantum-inspired or wave-based photonic systems. Even though there exists a range of investigations on EPs of order two and three (say, EP2s and EP3s, respectively), the hosting of fourth-order EPs (EP4s) in any real system and the exploration of associated topological features are lacking. Here we have designed a simple Fabry-Pérot type gain-loss-assisted open optical microcavity to host EPs up to order four. The scattering-matrix formalism has been used to analyze the microcavity numerically. With the appropriate modulation of the gain-loss profile in the same cavity geometry, we have encountered multiple different orders of EPs by investigating the simultaneous interactions among four coupled cavity states via level-repulsion phenomena. Besides affirming the second-order and third-order branch-point behaviors of the embedded EP2s and EP3s, the fourth-order branch-point functionality of an EP4 has been manifested by encircling three connecting EP2s simultaneously in the closed gain-loss parameter space. We have established a unique successive state-switching phenomenon among four coupled states by implementing such an EP4-encirclement scheme in the system's parameter space. The proposed scheme indeed offers potential applications in state-switching and control in quantum-inspired integrated photonic circuits, where the presence of an EP4 serves as a new light manipulation tool. © 2021 American Physical Society.

World University root node

Physical Review A

Successive switching among four states in a gain-loss-assisted optical microcavity hosting exceptional points up to order four

The thermoelectric materials so far discovered have shown thermoelectric behavior at relatively higher temperatures. Low temperature thermoelectric materials are the need of the hour and in this work we have studied the thermoelectric behavior of 2D monolayer of XI2 (X = Sn, Si) at relatively low temperature by using Density Functional Theory (DFT) along with the Boltzmann Transport equation. We have found high thermoelectric figure of merit (ZT) for SnI2 and SiI2 at 600 K. At room temperature the maximum ZT is 0.66 (0.35), 0.78 (0.51) for p-type (n-type) SnI2 and SiI2 respectively and at 600 K it is 0.83 for SiI2. The study of the optical properties of both the materials shows that both of them have indirect band gap with SnI2 having a band gap of 2.06 eV where as SiI2 has a band gap of 1.63 eV. Both the materials have a very high absorption coefficient in the ultraviolet (UV) region hence these materials can be used as high sensitive UV photodetectors. Thus the SnI2 and SiI2 2D monolayers can have potential application in optoelectronic as well as thermoelectric device fabrication. © 2020 Elsevier B.V.

Computational Materials Science

Low-temperature thermoelectric behavior and impressive optoelectronic properties of two-dimensional XI2 (X = Sn, Si): A first principle study

Gas sensing ability of one dimensional (1D) semiconducting WO3 Nanorods with remarkable aspect ratio is characterized. The WO3 sensor exhibited high response towards 10–100 ppm ethanol at 250 °C; 95% response for 100 ppm and 61% response at 10 ppm ethanol. The sensor revealed high selectivity towards ethanol among various gases. The dynamic response for different concentrations of ethanol was recorded and analysed. The sensor's repeatability was noted by transient response study for 100 ppm ethanol. The sensor stability and hypothesized sensing mechanism were discussed. According to the results, WO3 nanorods with high aspect ratio would be used in advanced ethanol sensor application. © 2021 Elsevier B.V.

Materials Letters

WO3 nanorods structures for high-performance gas sensing application

A series of diarylacetylene (tolane) derivatives functionalised at the 4- and 4′-positions by thiolate, thioether, or amine groups capable of serving as anchor groups to secure the molecules within a molecular junction have been prepared and characterised. The series of compounds have a general form X-B-X, Y-B-Y, and X-B-Y where X and Y represent anchor groups and B the molecular bridge. The single-molecule conductance values determined by the scanning tunnelling microscope break-junction method are found to be in excellent agreement with the predictions made on the basis of a recently proposed 'molecular circuit law', which states 'the conductance GXBY of an asymmetric molecule X-B-Y is the geometric mean √GXBXGYBY of the conductance of the two symmetric molecules derived from it, GXBX and GYBY.' The experimental verification of the circuit law, which holds for systems in which the constituent moieties X, B, and Y are weakly coupled and whose conductance takes place via off-resonance tunnelling, gives further confidence in the use of this relationship in the design of future compounds for use in molecular electronics research. © CSIRO 2021 Open Access.

Australian Journal of Chemistry

Experimental Validation of Quantum Circuit Rules in Molecular Junctions

Covalent functionalization is one of the most efficient ways to tune the properties of layered materials in a highly controlled manner. However, molecular chemisorption on semiconducting transition metal dichalcogenides remains a delicate task due to the inertness of their surface. Here we perform covalent modification of bulk and single layer molybdenum disulfide (MoS2) using chemical activation of diazonium salts. A high level of control over the grafting density and yield on MoS2 basal plane can be achieved by this approach. Using scanning probe microscopies and X-ray photoelectron spectroscopy we prove the covalent functionalization of MoS2. This journal is © The Royal Society of Chemistry.

Nanoscale

Covalent functionalization of molybdenum disulfide by chemically activated diazonium salts

Hydroxido-bridged dinuclear monoorganostannoxane [(RSnIV)2(μ-OH)(μ-OMe)Cl4]·CH3OH (R = 2-phenylazophenyl) (1) was obtained by the reaction of RSnCl3 (R = 2-phenylazophenyl) with sodium hydroxide in a stoichiometric ratio of acetone/methanol (1:1) at room temperature. Compound 1 crystallizes in the monoclinic space group Cc. The partial hydrolysis of RSnCl3 is accompanied by the substitution of two chlorides by one hydroxido and one methoxy ligand. The molecular structure of 1 contains two tin centers in distorted octahedral geometry which are bridged by hydroxido and methoxy ligands. In addition, single-crystal X-ray diffraction analysis of 1 revealed the formation of 1-D and 2-D supramolecular architectures because of the intermolecular hydrogen bonding and CH···πinteractions. Density functional theory studies suggested that the major transitions occurring in 1 involves ligand to ligand transitions. The reduced species calculations on compound 1 results are compatible to show the negative differential resistance (NDR) effect in this molecule. The I-V characteristic studies of a device made using compound 1 revealed that it exhibits very interesting NDR behavior in the region of 1.5-2.5 V. ©

ACS Applied Electronic Materials

Dinuclear Monoorganostannoxane [(RSnIV)2(μ-OH)(μ-OCH3)Cl4]·CH3OH (R= 2-(Phenylazo)phenyl) Assembled Using Intramolecular Coordination Approach: Design of Organostannoxane-Based NDR Device

The tension among measurements of Vus from different channels, the so-called Cabibbo Angle Anomaly, can be interpreted as a signal of lepton flavor universality (LFU) violation in the W boson couplings. We investigate this issue in the framework of effective field theory, keeping the gauge structure of the Standard Model (SM) unchanged. We introduce gauge-invariant dimension-6 effective operators that couple the Higgs doublet to leptons, thereby giving non-universal tree-level contributions to the couplings of electroweak gauge bosons. Due to the SU(2)L gauge symmetry, a tension arises between the Vus measurements that are affected by new W couplings, and the electroweak precision measurements, which are also affected by the new Z couplings. We show that this tension can be alleviated by allowing additional sources of gauge-invariant couplings of Z boson to left- or right-handed leptons, and find the optimal regions indicated by the current data in the Wilson-coefficient space. We illustrate our model-independent results with the examples of minimal extensions of the SM involving the vector-like lepton (VLL) models. We point out that dimension-6 operators coupling the Higgs doublet to leptons can affect the rate of h→ττ decay significantly in general, however this effect is restricted to less than a per cent level for the minimal VLL models. © 2021

Fulltext

Nuclear Physics B

The role of non-universal Z couplings in explaining the Vus anomaly

Salinity prompts heavy metals accumulation and adversely affects nutrient contents in soil and plants, thereby reducing crop yields. The assessment of domestic sewage sludge (SS) under saline conditions to boost crop productivity has become crucial. A field trial was conducted for two consecutive years (2017–2019) with three irrigation levels [canal water (0.35 dS m−1), I1; 8 dS m−1, I2; and 10 dS m−1 saline water, I3]; and five fertilization levels [control, F1; SS (5 t ha−1), F2; SS (5 t ha−1) + 50% RDF, F3; SS (5 t ha−1) + 75% RDF, F4; and RDF, F5]. The results revealed that treatment I3 (10 dS m−1) reduced the grain yield of pearl millet and wheat by an average of 31.2 and 32.6%, respectively, compared to I1 (0.35 dS m−1). However, among fertilizer treatments, F5 obtained significant highest grain and straw yields statistically at par with F4 treatment. Also, in the context of nutrients content in crops, a similar trend has been reported. In the addition, with the usage of saline irrigation (EC 8 and 10 dS m−1) and SS (5 t ha−1), the availability of heavy metals in crops and soil had increased (p = 0.05). The soluble ions in soil increased with increasing salinity levels of irrigation water. The extractability series of heavy metals were: Pb &gt; Co &gt; Ni &gt; Cr &gt; Cd. The addition of SS, however, recorded a higher concentration of DTPA-extractable metals in soil over control. The heavy metals content did not exceed toxicity levels in soil and plants. Hence, the incorporation of SS (5 t ha−1) resulted in saving 25% mineral fertilizers and, also combined use of SS with mineral fertilizers proved to be economically beneficial for crop production. © 2020, Springer Nature Switzerland AG.

International Journal of Plant Production

Sewage Sludge Impacts on Yields, Nutrients and Heavy Metals Contents in Pearl Millet–Wheat System Grown Under Saline Environment

The Belle II experiment started collecting data in summer 2018 and since then more than 176 fb−1 of integrated luminosity has been collected. With the current sample size, charm measurements are focused mostly on early reconstruction and studies of detector performance. In this proceeding, we present the current status and prospects of the charm measurements with the target luminosity of 50 ab−1 at Belle II. In particular, the D0 and D+ lifetime study, time-integrated charge-parity (CP) asymmetries, D0 − D0 mixing and decay-time-dependent CP violation measurements are discussed. © CHARM 2020.All right reserved.

Proceedings of Science

Charm status and prospects at Belle II

The direct detection of gravitational waves from binary mergers has been hailed as the discovery of the century. In the light of recent evidence on the existence of gravitational waves, it is now possible to know about the properties of matter under extreme conditions in compact astrophysical objects and different dynamical spacetimes. The foremost theme of the present article is to bring out the various features of the interaction between photons and gravitons that can be used in astrophysical observations. The effective action of interacting photons containing light–matter coupling and self-interaction term is constructed by eliminating the graviton degrees of freedom coupled to both matter and photons. It is shown that the equation of state of matter can be probed from the dynamics of light in this theory. The vacuum birefringence is also shown to be a generic property in this theory that arises from the nonlinear nature of the self-interaction between gauge fields. Further, the non-local nature of quantum effective action with modified dispersion relation is also discussed in great detail. The above results also open an alternate way to infer the properties of gravitational waves without their direct measurement using the features of photon–graviton interaction. © 2021, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.