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Publication Randomness efficient algorithms for estimating average gate fidelity via k-wise classical and quantum independence(Springer, 2025-12-16)We present three new algorithms for efficient in-place estimation of average fidelity of a d dimensional quantum logic gate, without using ancilla qubits. The main advantage of our algorithms is the much smaller usage of truly random bits compared to what was known so far. Reducing the requirement of classical seed randomness increases the reliability of estimation, as high quality random bits are usually an expensive computational resource. Commonly used sources of random bits are strictly speaking either pseudorandom or have a non-trivial bias. Previous approaches for this task replaced Haar random unitaries in the naive estimation algorithm by approximate unitary 2-designs by sampling them uniformly and independently. In contrast, in our first algorithm we sample the unitaries of the approximate unitary 2-design uniformly using a limited independence pseudorandom generator, highlighting the usage of computational derandomization theory for quantum computation. This algorithm uses random bits in contrast to random bits used in the previous works, with the same number of gate evaluations (c.f. [Dankert et al., Physical Rev. A 80, 012034 (2009)]). Our second efficient algorithm, uses a quantum 4-tensor product expander, in the regime of large gate dimension d and not ”too small” estimation error. It uses even lesser random bits than the first algorithm, and has the added advantage that it needs to implement only one unitary from an approximate 4-design as opposed to potentially all unitaries from an approximate 2-design in previous algorithms. This is significantly advantageous for NISQ machines and early fault tolerant quantum computers where one wants to minimize the number of times the quantum RAM needs to be loaded due to coherence time limitations. Our third efficient algorithm, based on an l-quantum tensor product expander for moderately large values of l, works for all values of the parameters. It uses slightly more random bits than the other algorithms but has the advantage that it needs to implement only a small number of unitaries from an approximate l-design versus potentially all the unitaries of an approximate 2-design in previous algorithms. This advantage can be of great importance to the experimental implementations in the near future. - Some of the metrics are blocked by yourconsent settings
Publication An enhanced optical design for wide-field imaging X-ray astronomy telescopes(Society of Photo-Optical Instrumentation Engineers, 2025-08)Wolter-1 (W1) and Wolter-Schwarzschild (WS) optical designs are widely used for narrow-field X-ray observations, providing high angular resolution along the axial direction. However, surface figure errors in mirror fabrication limit the theoretical on-axis resolution. Additionally, these designs suffer from inherent optical aberrations, resulting in a broader point spread function (PSF) at wider field angles, making them inefficient for wide-field applications, such as X-ray survey missions or solar X-ray imaging telescopes. To address these limitations, we introduced the Field-angle Optimized (FO) design, which is coma-free, similar to WS, but optimized to deliver a sharp PSF at any specified field angle. The FO design minimizes PSF size across all field angles, providing better overall imaging performance when averaged across the entire field of view compared to W1 and WS. The improvement in the performance of the FO design remains consistent across various telescope parameters, such as focal length, diameter, and mirror length, making it adaptable to different telescope configurations. The FO design provides significant improvements in wide-field X-ray imaging, enabling more efficient astronomical surveys and solar observations. - Some of the metrics are blocked by yourconsent settings
Publication A theory of locally impenetrable elastic tubes(Cornell University Library, 2025-11)We present a reduced order theory of locally impenetrable elastic tubes. The constraint of local impenetrability -- an inequality constraint on the determinant of the 3D deformation gradient -- is transferred to the Frenet curvature of the centerline of the tube via reduced kinematics. The constraint is incorporated into a variational scheme, and a complete set of governing equations, jump conditions, and boundary conditions are derived. It is shown that with the local impenetrability actively enforced, configurations of an elastic tube comprise segments of solutions of the Kirchhoff rod theory appropriately connected to segments of constant Frenet curvature. The theory is illustrated by way of three examples: a fully flexible tube hanging under self-weight, an elastic tube hanging under self-weight, and a highly twisted elastic tube. - Some of the metrics are blocked by yourconsent settings
Publication Cost-effective porous metal oxides and mixed metal oxides coatings for Ti- 6Al-4V biomedical implants(2025-12-17)Titanium metal and its alloys, such as Ti– 6Al–4V, are widely used for fabricating biomedical implants due to their excellent mechanical and antibacterial properties. However, these implant materials require surface modifications to address limitations in corrosion resistance and biocompatibility. In this regard, porous coatings are essential, as they significantly promote the survival of bone-forming cells (osteoblasts) and support tissue ingrowth into the implant. This leads to improved implant stability and a reduced risk of implant loosening. This study focuses on modifying Ti–6Al–4V surfaces using a cost-effective bottom-up sol–gel method to prepare TiO2, Ta2O5, and TiO2– Ta2O5 nanocomposites in 1:2, 1:1, and 2:1 ratios. A spin-coating technique with optimized rotational speed and deposition time was employed to deposit uniform films onto the Ti–6Al– 4V substrate. Microstructural characterization of the prepared films revealed porous architectures with varying pore sizes, uniform film thickness, and stoichiometric formation of the desired metal oxides and their composites. A detailed corrosion study was conducted in Hank’s solution and simulated body fluid (SBF). Tafel plots and electrochemical impedance spectroscopy (EIS) demonstrated high corrosion resistance, with Icorr values on the order of 10-8 A cm-2 for the coated samples. Pulloff adhesion testing confirmed excellent film-tosubstrate adhesion, effectively overcoming one of the most common limitations of sol–gel-derived coatings. The prepared porous films also exhibited enhanced cell viability and attachment compared to bare Ti–6Al–4V when tested with MG-63 (cancerous osteoblast) and NIH3T3 (fibroblast) cell lines over 1, 3, and 7 days. Overall, this study highlights the efficacy of the cost-effective coating technique and demonstrates the superior surface properties of TiO2, Ta2O5, and TiO2– Ta2O5 composite films relative to bare Ti–6Al– 4V implants. - Some of the metrics are blocked by yourconsent settings
Publication Dopant induced room temperature phase transition in vanadium dioxide thin films(2025-12-17)An ever-increasing energy demand due to rapid urbanization has led to a continuous need for innovative, sustainable, and energy-efficient smart building designs. Windows constitute about ∼ 50% of the total heat loss from a typical household. In this regard, regular window designs could be improved to not only have adequate visible transparency but also modulate IR radiation based on the requirement. The improved smart window design could incorporate either electrochromic or thermochromic coatings, which change their optical behavior in response to external stimuli. Whereas electrochromic coatings require electrical power to function and thus are not suitable for energyefficient smart windows, thermochromic coatings can alter their optical properties solely based on external/internal temperature. One of the promising materials that display thermochromism is vanadium dioxide (VO2), which undergoes a structural phase transition (SPT) from monoclinic to rutile crystal structure at 341 K (68◦C). This structural transition is coupled with a semiconductor-to-metal transition (SMT), which switches the optical behavior of this material from an IR-transparent state to an IR-reflecting state. However, the phase transition temperature (Tc) for pure VO2 is slightly on the higher side and needs to be brought down near room temperature for its commercial applicability. One of the strategies to reduce Tc utilizes the lattice-straining method, wherein the material is strained, causing its transition to occur earlier or later depending on the type of strain. Whereas mechanical straining requires epitaxial thin-film growth and has thickness dependence, chemical straining uses dopant atoms to strain the host lattice and is thickness independent. In this work, unstrained and chemically strained VO2 thin films are deposited on soda–lime glass (SLG) substrates using compound ceramic targets in an RF magnetron sputtering system. Four different dopants, each with varying ionic sizes and concentrations (W6+, Mo6+, Nb5+, and Ta5+), were incorporated to modify the switching behavior and transition temperature (Tc) of the VO2 thin films. The chemically strained thin films were found to have their Tc in the range of 175 K to 334 K, depending on dopant type and concentration. Moreover, chemically strained VO2 shows switching characteristics with Tc = 310 ± 7 K, while also maintaining adequate luminous transmittance of 34.50% and a high infrared switching efficiency of 40.93% at λ = 2500 nm. Furthermore, the role of microstructure (crystallite size, stoichiometry, etc.) in altering the phase transition behavior has been studied. The obtained experimental results could help establish VO2 as a potential next-generation material for various energy-efficient device applications.
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Publication Multi-stage scheduling for a smart home with solar PV and battery energy storage - A case study(2016-01-19)In this paper, a multi-stage optimal scheduling and controlling approach has been studied which performs the scheduling of household appliances and management of local energy resources with respect to conflicting objectives. Firstly, a compromisation between computational complexity vs parameters uncertainty by considering multistage scheduling. Second, a choice for scheduling its shiftable appliances either by home energy management system (HEMS) or by coordinating/negotiating with aggregator for further benefit and overall peak reduction by decomposing this from its local energy resources management. Third, coordination between day-ahead scheduling and real-time demand response (DR) by considering time receding optimization of these strategies. Fourth, consideration of physical based load models for assessment of DR potential and actions. A typical home energy management problem is synthesized by assuming a rooftop solar PV, battery storage and ability to buy/sell electricity from/to aggregator. Simulation results shows that applied evolutionary techniques and the proposed strategy not only reduces energy consumption costs by responding to DR signals but also alleviates peak-to-average ratio and ensures the comfort preferences.Scopus© Citations 12 - Some of the metrics are blocked by yourconsent settings
Publication Harappan blade implements: a literature review and future perspectives(University of Kerla (Department of Archealogy), 2018-12-01) - Some of the metrics are blocked by yourconsent settings
Publication Characteristics of remnant radio galaxies detected in deep radio continuum observations from SKA pathfinders(2022-12-01)The cessation of AGN activity in radio galaxies leads to a remnant phase during which jets are no longer sustained, but lobes can be detected for a period of time before they fade away due to radiative and dynamical energy losses. The time-scale of the remnant phase and AGN duty cycle are vital to understand the evolution of radio galaxies. In this paper, we report new band-3 observations with the upgraded Giant Meterwave Radio Telescope (uGMRT) for five remnant radio galaxies. Our uGMRT observations reveal emission of low-surface-brightness in all five remnants with 400 MHz surface brightness in the range of 36–201 mJy arcmin- 2. With band-3 uGMRT observations, we discover wing-shaped radio morphology in one of our sample sources. Using radio observations at 150, 325, 400 MHz and 1.5 GHz, we model the radio spectral energy distributions (SEDs) of our sample sources with the continuous injection-off (CIOFF) model, that assumes an active phase with continuous injection followed by a remnant phase. We obtain total source ages (ts) in the range of 20.3–41.4 Myr with tOFF/ ts distributed in the range of 0.16–0.63, which in turn suggests that they belong to different evolutionary phases. We note that when compared to the remnants reported in the literature, our sample sources tend to show lower spectral ages that can be explained by the combined effects of more dominant inverse Compton losses for our sources present at the relatively higher redshifts and possible rapid expansion of lobes in their less dense environments. - Some of the metrics are blocked by yourconsent settings
Publication Implementation of an F-statistic all-sky search for continuous gravitational waves in Virgo VSR1 data(2014-08-21)We present an implementation of the F-statistic to carry out the first search in data from the Virgo laser interferometric gravitational wave detector for periodic gravitational waves from a priori unknown, isolated rotating neutron stars. We searched a frequency f0 range from 100 Hz to 1 kHz and the frequency dependent spindown f1 range from -1.6(f0/100 Hz) ×10-9 Hz s?1 to zero. A large part of this frequencyspindown space was unexplored by any of the all-sky searches published so far. Our method consisted of a coherent search over two-day periods using the F-statistic, followed by a search for coincidences among the candidates from the two-day segments. We have introduced a number of novel techniques and algorithms that allow the use of the fast Fourier transform (FFT) algorithm in the coherent part of the search resulting in a fifty-fold speed-up in computation of the F-statistic with respect to the algorithm used in the other pipelines. No significant gravitational wave signal was found. The sensitivity of the search was estimated by injecting signals into the data. In the most sensitive parts of the detector band more than 90% of signals would have been detected with dimensionless gravitationalwave amplitude greater than 5 ×10?24. © 2014 IOP Publishing Ltd.Scopus© Citations 41 - Some of the metrics are blocked by yourconsent settings
Publication Study of hydrodynamics and sediment transportation at coastal Hazira, Bay of Khambhat, Gujarat(Indian Institute of Technology, Gandhinagar, 2020-01-01)