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 plateau in the duration distribution of long gamma-ray bursts (LGRBs) provides a direct observational evidence for the Collapsar model. The plateau reflects the fact that the observed duration satisfies: T90 = te-tb where te is the time that the central engine operates and tb is the threshold time, interpreted within the Collapsar model as the time it takes for the relativistic jet to penetrate the stellar envelope. Numerical simulation and macronova observations suggest that compact binary mergers involve mass ejection. If short-gamma ray bursts (sGRBs) arise from such mergers, their jets should cross this surrounding ejecta before producing the prompt emission. Like in LGRBs, this should result in a distinct short plateau in the GRBs' duration distribution.We present a new analysis of the duration distribution for the three GRB satellites: BATSE, Swift and Fermi. We find a clear evidence for a short (~0.4 s) plateau in the duration distribution. This plateau is consistent with the expected jet crossing time, provided that the ejecta is of order of a few percent of solar masses. © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

World University root node

Fulltext

Monthly Notices of the Royal Astronomical Society: Letters

Observational evidence for mass ejection accompanying short gamma-ray bursts

Thermal emittance is an important parameter for the solar thermal collectors as thermal radiative losses from the solar thermal collector increase to the fourth power of temperature. This should be minimized using infrared reflectors in designing spectrally selective absorber coatings for solar thermal applications. The thermal emittance of zirconium (Zr) film as an infrared reflector has been investigated for the use in the spectrally selective absorber. The Zr metallic films are deposited using DC magnetron sputtering process on stainless steel and glass substrates and the deposition process has been optimized to achieve the minimum thermal emittance. The effect of structural, microstructural and surface morphological properties of Zr films is investigated on the emittance of fabricated structures. The X-ray diffraction analysis revealed that the Zr film coatings consist of both cubic and hexagonal Zr crystallographic phase. The optimized deposition time and temperature showed 0.12 and 0.14 emittance values for Zr film coatings on stainless steel and glass substrates respectively. © 2017 Elsevier B.V.

Department of Mathematics

Department of Mechanical Engineering

Thin Solid Films

Optimization of sputtered zirconium thin films as an infrared reflector for use in spectrally-selective solar absorbers

The investigation is focussed on phase generation and magnetocaloric properties of a series of Ni77-XMnXGa23 (x = 22, 23, 24, 25, 27) alloys prepared through arc melting furnace. With increase in Mn content, the alloys showed systematic transition from a non-modulated martensite (NM) to a fully austenitic parent phase through an appearance and coexistence of modulated (M) structure. Intermediate Mn containing alloy (#Mn24) not only displayed high magnetic entropy change (ΔSM) of −7.7 J/kg−1K−1 but also large Refrigerant Capacity (RC) of 169 J.Kg−1 at magnetic field change of 3 T compared to other alloys. The coexisting martensite (NM, M) and parent austenite as well as overlapping thermomagnetic and structural transformation was deliverable through tuning of alloy chemistry wherein Ni was systematically substituted by Mn. Transmission electron microscopy (TEM) supported the proposition with existence of martensite plates of different morphology in Mn24 alloy exhibiting superior magnetocaloric properties. © 2017 Elsevier B.V.

Journal of Magnetism and Magnetic Materials

Enhancement in magnetocaloric properties of NiMnGa alloy through stoichiometric tuned phase transformation and magneto-thermal transitions

We report a specially configured open optical microcavity, imposing a spatially imbalanced gain–loss profile, to host an exclusively proposed next-nearest-neighbor resonance coupling scheme. Adopting the scattering matrix (S-matrix) formalism, the effect of interplay between such proposed resonance interactions and the incorporated non-Hermiticity in the microcavity is analyzed drawing a special attention to the existence of hidden singularities, namely exceptional points (EPs), where at least two coupled resonances coalesce. We establish adiabatic flip-of-state phenomenon of the coupled resonances in the complex frequency plane (k-plane), which is essentially an outcome of the fact that the respective EP is being encircled in the system parameter plane. Encountering such multiple EPs, the robustness of flip-of-states phenomena has been analyzed via continuous tuning of coupling parameters along a special hidden singular line which connects all the EPs in the cavity. Such a numerically devised cavity, incorporating the exclusive next neighbor coupling scheme, has been designed for the first time to study the unconventional optical phenomena in the vicinity of EPs. © 2017 Optical Society of America.

Journal of the Optical Society of America B: Optical Physics

Next-nearest-neighbor resonance coupling and exceptional singularities in degenerate optical microcavities

We report formation and improved stable propagation of self-similar parabolic pulsesthrough chalcogenide glass based chirped-clad Bragg fiber at 3 μ m wavelength. We employ alongitudinally varying dispersion landscape with close to zero average dispersion. © 2017 SPIE. All rights reserved.

Proceedings of SPIE - The International Society for Optical Engineering

Stable propagation of self similar pulses through a chirped-clad all-solid bragg fiber in the mid-ir

We demonstrate self-similar stable propagation of parabolic optical pulses through a highly nonlinear specialty Bragg fiber at 2.8 μm by a numerical approach. To obtain such propagation characteristics over a longer length of a Bragg fiber, we propose and verify a fiber design scheme that underpins passive introduction of a rapidly varying group-velocity dispersion around its zero dispersion wavelength and modulated nonlinear profile through suitable variation in its diameter. To implement the proposed scheme, we design a segmented and tapered chalcogenide Bragg fiber in which a Gaussian pulse is fed. Transformation of such a launched pulse to a self-similar parabolic pulse with full-width-at-half-maxima of 4.12 ps and energy of ∼39 pJ is obtained at the output. Furthermore, a linear chirp spanning across the entire pulse duration and 3 dB spectral broadening of about 38 nm at the output are reported. In principle, the proposed scheme could be implemented in any chosen set of materials. © 2017 IEEE.

IEEE Photonics Journal

Toward Self-Similar Propagation of Optical Pulses in a Dispersion Tailored, Nonlinear, and Segmented Bragg-Fiber at 2.8 μm

International Journal of Materials Science

Growth of Highly Crystalline Bundles of WO3 Nanorod under Facile Hydrothermal Condition

At present, there are several measurements of B decays that exhibit discrepancies with the predictions of the SM, and suggest the presence of new physics (NP) in b→sμ+μ- transitions. Many NP models have been proposed as explanations. These involve the tree-level exchange of a leptoquark (LQ) or a flavor-changing Z′ boson. In this paper we examine whether it is possible to distinguish the various models via CP-violating effects in B→K(∗)μ+μ-. Using fits to the data, we find the following results. Of all possible LQ models, only three can explain the data, and these are all equivalent as far as b→sμ+μ- processes are concerned. In this single LQ model, the weak phase of the coupling can be large, leading to some sizable CP asymmetries in B→K(∗)μ+μ-. There is a spectrum of Z′ models; the key parameter is gLμμ, which describes the strength of the Z′ coupling to μ+μ-. If gLμμ is small (large), the constraints from Bs0-B-s0 mixing are stringent (weak), leading to a small (large) value of the NP weak phase, and corresponding small (large) CP asymmetries. We therefore find that the measurement of CP-violating asymmetries in B→K(∗)μ+μ- can indeed distinguish among NP b→sμ+μ- models. © 2017 American Physical Society.

Physical Review D

New physics in b →sμ+μ-: Distinguishing models through CP -violating effects

In order to elucidate the mechanism of lithium transport in intercalation electrodes based on solid lithium-accumulating compounds and determine its parameters, the kinetic models are used which allow the combined analysis of electrode impedance spectroscopy, cyclic voltammetry, pulse chronoampero- and chronopotentiometry data to be carried out. The models describe the stages of consecutive lithium transport in the surface layer and bulk of electrode-material particles, including the accumulation of species in the bulk. The lithium transport stages that occur in the surface layer of an intercalation-material particle and in its bulk are both of the diffusion nature but substantially differ as regards their characteristic times and diffusion coefficients D. Taking account of this peculiarity and assessing adequately the geometrical configuration of intercalation system allow the diffusion parameters of lithium transport to be correctly determined. © 2017, Pleiades Publishing, Ltd.

Russian Journal of Electrochemistry

Models of lithium transport as applied to determination of diffusion characteristics of intercalation electrodes

Quantum discord refers to an important aspect of quantum correlations for bipartite quantum systems. In our earlier works, we have shown that corresponding to every graph (combinatorial) there are quantum states whose properties are reflected in the structure of the corresponding graph. Here, we attempt to develop a graph theoretic study of quantum discord that corresponds to a necessary and sufficient condition of zero quantum discord states which says that the blocks of density matrix corresponding to a zero quantum discord state are normal and commute with each other. These blocks have a one-to-one correspondence with some specific subgraphs of the graph which represents the quantum state. We obtain a number of graph theoretic properties representing normality and commutativity of a set of matrices which are indeed arising from the given graph. Utilizing these properties, we define graph theoretic measures for normality and commutativity that results in a formulation of graph theoretic quantum discord. We identify classes of quantum states with zero discord using the developed formulation. © 2017, Springer Science+Business Media, LLC.