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A simple, accurate, precise spectrophotometric method was developed for the detection of Pirenzepine dihydrochloride (PZC). The optimum condition for the analysis of the drug was studied. PZC was subjected to stress degradation under different conditions like acidic, alkali, neutral, oxidation, photolytic, and thermal degradation as per recommended by the International Conference on Harmonization (ICH). The samples thus prepared were used for degradation studies by with the developed method. The lambda max i.e. absorption maxima found at 281nm and calibration curve linear over the range of 0-20µg/ml. The standard regression equation and correlation coefficient fond to be y = 0.04x + 0.056 R² = 0.998 respectively. Percent RSD found to be less than one. The accepted limits of accuracy (recovery) were found to be 90% - 120% and all observed data are within required range which indicates good recovery value. and LOD and LOQ found to be 0.165 and 0.500 respectively by simple UV spectroscopy.

Objective: Over past few decades, Peptic ulcer disease remains a common condition despite the lots of novelty in treatment. The objective of this research work was to formulate gastro retentive floating tablet by raft approach using Pirenzepine dihydrochloride (PNZ) as drug candidate. Formulation also contained a raft forming agent (sodium alginate) along with alkalizing agents (Calcium carbonate and Sodium Bicarbonate). Raft strength was only affected by the amount of Raft forming agent, Calcium carbonate and Sodium Bicarbonate. Method: Tablets were prepared by direct compression method and evaluated for raft strength, acid neutralization capacity, weight variation, % drug content, thickness, hardness, friability and In vitro drug release. Experimental work: A Box Behnken design was used in present study for optimization. Amount of gel forming agent, amount of cross-linkingagentsand floating agent were selected as independent variables. Raft strength, Acid neutralization capacity, and drug release were selected as dependent variables. Result: Raft strength, Acid neutralization capacity and In vitro drug release of all the experimental batches were found to be satisfactory. F10 batch was optimized based on maximum raft strength, good acid neutralization capacity and control drug release. Drug-excipients compatibility study showed no interaction between drug and excipients.

Soliton microcombs -- phase-locked microcavity frequency combs -- have become the foundation of several classical technologies in integrated photonics, including spectroscopy, LiDAR, and optical computing. Despite the predicted multimode entanglement across the comb, experimental study of the quantum optics of the soliton microcomb has been elusive. In this work, we use second-order photon correlations to study the underlying quantum processes of soliton microcombs in an integrated silicon carbide microresonator. We show that a stable temporal lattice of solitons can isolate a multimode below-threshold Gaussian state from any admixture of coherent light, and predict that all-to-all entanglement can be realized for the state. Our work opens a pathway toward a soliton-based multimode quantum resource.

Objective: Over past few decades, Peptic ulcer disease remains a common condition despite the lots of novelty in treatment. The objective of this research work was to formulate gastro retentive floating tablet by raft approach using Pirenzepine dihydrochloride (PNZ) as drug candidate. Formulation also contained a raft forming agent (sodium alginate) along with alkalizing agents (Calcium carbonate and Sodium Bicarbonate). Raft strength was only affected by the amount of Raft forming agent, Calcium carbonate and Sodium Bicarbonate . Method: Tablets were prepared by direct compression method and evaluated for raft strength, acid neutralization capacity, weight variation, % drug content, thickness, hardness, friability and In vitro drug release. Experimental work: A Box Behnken design was used in present study for optimization. Amount of gel forming agent, amount of cross-linkingagentsand floating agent were selected as independent variables. Raft strength, Acid neutralization capacity, and drug release were selected as dependent variables. Result:Raft strength, Acid neutralization capacity and In vitro drug release of all the experimental batches were found to be satisfactory. F10 batch was optimized based on maximum raft strength, good acid neutralization capacity and control drug release. Drug-excipients compatibility study showed no interaction between drug and excipients.

Background Objective of present research work is to develop and validate cost-effective analytical tool for determination of camptothecin (CPT) and determine its anticancer potential against prostate cancer LNCaP cell lines. Structural elucidation has been performed by mass spectrometry, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and MTT assay utilized for in vitro cytotoxicity where spectrometric method was used for estimation of camptothecin. Results Mass spectra showed peak at 349.2 which matches to standard molecular weight of camptothecin. FTIR and NMR spectra conformed functional moieties and structure of isolated camptothecin which was nearly equal to values mentioned in standard structure of camptothecin. IC50 values of CPT against LNCaP cell lines was found to be 3.561 μg/ml. Lambda max of CPT was found to be at 225 nm and calibration curve found to be linear over the concentration range from 2 to 70 μg/ml of camptothecin. Developed method was found to be linear, accurate, and precise. LOD and LOQ were found to be 0.0524 μg/ml and 0.1614 μg/ml, respectively. Developed method has % relative standard deviation less than one which is reproducible hence % recovery was found to be 99.80%. Conclusions FTIR, NMR, and mass spectrometry results conforms isolated compound was camptothecin; cytotoxicity study proves it has strong potential in treatment of prostate carcinoma as competent alternative to chemotherapy in the form of herbal medicine and the developed UV method proves to be valid, sensitive, and applicable for rapid, accurate, precise, and economical determination of camptothecin.

Aim: To estimate the differences in the maxillary arch morphology in buccal and palatal canine impaction in an Asian population of Gujarati origin. Methodology: An institutional ethics committee’s approval was acquired before the commencement of this study. Sixty subjects were enrolled in the study. Thirty subjects (20 females and 10 males) had a maxillary impacted canine either buccal or palatal and thirty control group participants were selected aged 13 to 18 years who sought orthodontic treatment at the tertiary health care center in Ahmedabad, Gujarat, in western India. Routine pre-treatment radiographs and dental plaster models with good anatomic details were recorded. Measurements of the inter-molar width, palatal depth, arch length, sum of the mesio-distal width of the upper incisors, and available arch space were recorded from prepared orthodontic study models using digital vernier calipers with an accuracy of 0.01 mm and brass wire. The ratio of palatal depth to inter-molar width (Ratio 1), arch length to inter-molar width (Ratio 2), and width of the maxillary incisors to available arch space (Ratio 3) were also secondarily calculated. Data were analyzed using Statistical Package for Social Sciences (SPSS) version 21, IBM Inc. The normality of the data was assessed by the Shapiro–Wilk test. As the data was found to be normally distributed, bivariate analyses were also performed (one-way ANOVA test, Bonferroni post hoc correction). The level of statistical significance was set at a p-value less than 0.05. Results: The comparison of the inter-molar width, palatal depth, arch length, sum of the mesio-distal width of the upper incisors, available arch space, Ratio 1, Ratio 2, and Ratio 3 among controls and subjects with buccal and palatal canine impaction showed overall significant differences in the inter-molar width, palatal depth, arch length, sum of the mesio-distal width of the upper incisors, and available arch space when compared using one-way ANOVA as p < 0.05. Ratios 1, 2, and 3 also showed significant differences between the buccal and palatal canine impaction. Conclusion: An inadequate arch length (p < 0.0001) and a higher degree of crowding with reduced available arch space (p < 0.0001) may be considered as early risk factors for buccal maxillary canine impaction. An inadequate inter-molar width (p < 0.0001), and an increased palatal depth (p < 0.0001) with a clinically reduced mesiodistal width of the sum of maxillary incisors may be considered as risk factors for palatal maxillary canine impaction in an Asian population of Gujarati origin.

Malocclusions in the vertical plane are more difficult to treat as compared to the malocclusions in the sagittal plane as they often require multidisciplinary (surgical) approach. Skeletal vertical deficiency and excess causes jaw discrepancies in the sagittal vector too due to rotation of the mandible, thus presenting a complex situation which requires astute treatment planning and implementation. In this article, two cases treated with combined orthodontics and orthognathic surgery to treat skeletal class II malocclusion with vertical deficiency and excess are shown and all details of treatment planning are discussed.

We generate soliton microcombs in silicon-carbide-on-insulator microrings with a minimum operation power of 2.3 mW in the input waveguide. Using a single-photon optical spectrum analyzer, we study the multimode quantum correlations of soliton micro-combs.

Optical quantum information processing will require highly efficient photonic circuits to connect quantum nodes on-chip and across long distances. This entails the efficient integration of optically addressable qubits into photonic circuits, as well as quantum frequency conversion to the telecommunications band. 4H-silicon carbide (4H-SiC) offers unique potential for on-chip quantum photonics, as it hosts a variety of promising colour centres and has a strong second-order optical nonlinearity. Here, we demonstrate within a single, monolithic platform the strong enhancement of emission from a colour centre and efficient optical frequency conversion. We develop a fabrication process for thin films of 4H-SiC, which are compatible with industry-standard, CMOS nanofabrication. This work provides a viable route towards industry-compatible, scalable colour-centre-based quantum technologies, including the monolithic generation and frequency conversion of quantum light on-chip. Monolithic photonics devices based on SiC are fabricated by a wafer bonding and thinning technique. The strong enhancement of single-photon emission from a colour centre and optical frequency conversion with an efficiency of 360% W−1 are demonstrated.

Designing modern photonic devices often involves traversing a large parameter space via an optimization procedure, gradient based or otherwise, and typically results in the designer performing electromagnetic simulations of a large number of correlated devices. In this paper, we investigate the possibility of accelerating electromagnetic simulations using the data collected from such correlated simulations. In particular, we present an approach to accelerate the Generalized Minimal Residual (GMRES) algorithm for the solution of frequency-domain Maxwell’s equations using two machine learning models (principal component analysis and a convolutional neural network). These data-driven models are trained to predict a subspace within which the solution of the frequency-domain Maxwell’s equations approximately lies. This subspace is then used for augmenting the Krylov subspace generated during the GMRES iterations, thus effectively reducing the size of the Krylov subspace and hence the number of iterations needed for solving Maxwell’s equations. By training the proposed models on a dataset of wavelength-splitting gratings, we show an order of magnitude reduction (~10–50) in the number of GMRES iterations required for solving frequency-domain Maxwell’s equations.

A transducer of single photons between microwave and optical frequencies can be used to realize quantum communication over optical fiber links between distant superconducting quantum computers. A promising scalable approach to constructing such a transducer is to use ensembles of quantum emitters interacting simultaneously with electromagnetic fields at optical and microwave frequencies. However, inhomogeneous broadening in the transition frequencies of the emitters can be detrimental to this collective action. In this article, we utilise a gradient-based optimization strategy to design the temporal shape of the laser field driving the transduction system to mitigate the effects of inhomogeneous broadening. We study the improvement of transduction efficiencies as a function of inhomogeneous broadening in different single-emitter cooperativity regimes and correlate it with a restoration of superradiance effects in the emitter ensembles. Furthermore, to assess the optimality of our pulse designs, we provide certifiable bounds on the design problem and compare them to the achieved performance., 8 pages, 5 figures; added calculation of upper bounds; added new appendices; expanded the introduction

Non-Markovian effects are important in modeling the behavior of open quantum systems arising in solid-state physics, quantum optics as well as in study of biological and chemical systems. The non-Markovian environment is often approximated by discrete bosonic modes, thus mapping it to a Lindbladian or Hamiltonian simulation problem. While systematic constructions of such modes have been previously proposed, the resulting approximation lacks rigorous and general convergence guarantees. In this letter, we show that under some physically motivated assumptions on the system-environment interaction, the finite-time dynamics of the non-Markovian open quantum system computed with a sufficiently large number of modes is guaranteed to converge to the true result. Furthermore, we show that this approximation error typically falls off polynomially with the number of modes. Our results lend rigor to classical and quantum algorithms for approximating non-Markovian dynamics.

Temporary anchorage device-assisted rapid maxillary expansion has widened the horizon to treat adults having maxillary transverse deficiency without any surgical procedure. Three-dimensional custom modifications have also been developed, but they can be expensive. A modification of Hyrax screw with the use of lingual sheaths is suggested for microimplant-assisted rapid palatal expansion, which can be an easy to fabricate in-office and economical option.

Inverse design methods produce nanophotonic devices with arbitrary geometries that show high efficiencies as well as novel functionalities. Ensuring fabricability during optimization of these unrestricted device geometries is a major challenge for these design methods. In this work, we construct a fabrication constraint penalty function for level set geometry representations of these devices. This analytical penalty function limits both the gap size and boundary curvature of a device. We incorporate this penalty in a fully automated optical design flow using a quasi-Newton optimization method. The performance of our design method is evaluated by designing a series of waveguide demultiplexers (WDM) and mode converters with various footprints and minimum feature sizes. Finally, we design and experimentally characterize three WDMs with a 80 nm, 120 nm and 160 nm feature size.

Optimized process and reduced cost of ownership are important considerations for Chemical Mechanical Planarization. Slurry blending and distribution systems can have a significant impact on Chemical Mechanical Planarization process performance especially for state-of-the-art semiconductor technology nodes. Design of Slurry Delivery Systems plays an important role in slurry blending and distribution but is often overlooked. Improved Slurry Delivery System design can lead to low cost of ownership, yield improvement and higher tool uptime for a fleet of Chemical Mechanical Planarization tools.We highlight some critical aspects of Slurry Delivery System design to improve blending, Slurry Delivery System uptime, real-time analytical parameter monitoring and to reduce slurry agglomeration. We compare Slurry Delivery Systems with and without these design features in order to emphasize the importance of good Slurry Delivery System design.

Matrix powering is a fundamental computational primitive in linear algebra. It has widespread applications in scientific computing and engineering and underlies the solution of time-homogeneous linear ordinary differential equations, simulation of discrete-time Markov chains, or discovering the spectral properties of matrices with iterative methods. In this paper, we investigate the possibility of speeding up matrix powering of sparse stable Hermitian matrices on a quantum computer. We present two quantum algorithms that can achieve speedup over the classical matrix powering algorithms: (i) a fast-forwarding algorithm that builds on construction of Apers and Sarlette [Quantum Inf. Comput. 19, 181 (2019)] and (ii) an algorithm based on Hamiltonian simulation. Furthermore, by mapping the $N$-bit parity determination problem to a matrix powering problem, we provide no-go theorems that limit the quantum speedups achievable in powering non-Hermitian matrices.

We use numerical optimization to design the temporal shape of the laser field driving an inhomogeneous ensemble of quantum emitters in order to restore superradiance effects and improve single photon microwave-to-optical transduction efficiencies.

We study the scattering of photons from periodically modulated quantum-optical systems. For excitation-number-conserving quantum-optical systems, we connect the analytic structure of the frequency-domain $N$-photon scattering matrix of the system to the Floquet decomposition of its effective Hamiltonian. Furthermore, it is shown that the first-order contribution to the transmission or equal-time $N$-photon correlation spectrum with respect to the modulation frequency is completely geometric in nature, i.e., it depends only on the Hamiltonian trajectory and not on the precise nature of the modulation being applied.

The design of the scattering properties of electromagnetic structures is of fundamental interest in optical science and engineering. While there has been great practical success in applying local optimization methods to electromagnetic device design, it is unclear whether the performance of the resulting designs is close to that of the best possible design. This question remains open for absorptionless electromagnetic devices, since the absence of material loss makes it difficult to provide provable bounds on their scattering properties. We resolve this problem by providing nontrivial lower bounds on performance metrics that are convex functions of the scattered fields. Our bounding procedure relies on accounting for a constraint on the electric fields inside the device, which can be provably constructed for devices with small footprints or low dielectric contrast. We illustrate our bounding procedure by upper bounding the scattering cross sections of lossless dielectric and metallic particles.

The ability to shape photon emission facilitates strong photon-mediated interactions between disparate physical systems, thereby enabling applications in quantum information processing, simulation and communication. Spectral control in solid state platforms such as color centers, rare earth ions, and quantum dots is particularly attractive for realizing such applications on-chip. Here we propose the use of frequency-modulated optical transitions for spectral engineering of single photon emission. Using a scattering-matrix formalism, we find that a two-level system, when modulated faster than its optical lifetime, can be treated as a single-photon source with a widely reconfigurable photon spectrum that is amenable to standard numerical optimization techniques. To enable the experimental demonstration of this spectral control scheme, we investigate the Stark tuning properties of the silicon vacancy in silicon carbide, a color center with promise for optical quantum information processing technologies. We find that the silicon vacancy possesses excellent spectral stability and tuning characteristics, allowing us to probe its fast modulation regime, observe the theoretically-predicted two-photon correlations, and demonstrate spectral engineering. Our results suggest that frequency modulation is a powerful technique for the generation of new light states with unprecedented control over the spectral and temporal properties of single photons., 9 pages, 6 figures; Supplementary Information

We investigate the degree of indistinguishability of cascaded photons emitted from a three-level quantum ladder system; in our case the biexciton-exciton cascade of semiconductor quantum dots. For the three-level quantum ladder system we theoretically demonstrate that the indistinguishability is inherently limited for both emitted photons and determined by the ratio of the lifetimes of the excited and intermediate states. We experimentally confirm this finding by comparing the quantum interference visibility of noncascaded emission and cascaded emission from the same semiconductor quantum dot. Quantum optical simulations produce very good agreement with the measurements and allow us to explore a large parameter space. Based on our model, we propose photonic structures to optimize the lifetime ratio and overcome the limited indistinguishability of cascaded photon emission from a three-level quantum ladder system.

Bound states arise in waveguide QED systems with a strong frequency-dependence of the coupling between emitters and photonic modes. While exciting such bound-states with single-photon wave-packets is not possible, photon-photon interactions mediated by the emitters can be used to excite them with two-photon states. In this Letter, we use scattering theory to provide upper limits on this excitation probability for a general non-Markovian waveguide QED system and show that this limit can be reached by a two-photon wave packet with vanishing uncertainty in the total photon energy. Furthermore, we also analyze multi-emitter waveguide QED systems with multiple bound states and provide a systematic construction of two-photon wave packets that can excite a given superposition of these bound states. As specific examples, we study bound-state trapping in waveguide QED systems with single and multiple emitters and a time-delayed feedback.

High-quality sources of single photons are of paramount importance for quantum communication, sensing and metrology. To these ends, resonantly excited two-level systems based on self-assembled quantum dots have recently generated widespread interest. Nevertheless, we have recently shown that for resonantly excited two-level systems, emission of a photon during the presence of the excitation laser pulse and subsequent re-excitation results in a degradation of the obtainable single-photon purity. Here, we demonstrate that generating single photons from self-assembled quantum dots with a scheme based on two-photon excitation of the biexciton strongly suppresses the re-excitation. Specifically, the pulse-length dependence of the multi-photon error rate reveals a quadratic dependence in contrast to the linear dependence of resonantly excited two-level systems, improving the obtainable multi-photon error rate by several orders of magnitude for short pulses. We support our experiments with a new theoretical framework and simulation methodology to understand few-photon sources., We have included a Jupyter notebook as Supplemental Material which outlines how to perform the calculations in this paper using the Quantum Optics Toolbox in Python (QuTiP)

Temperature is one of the parameters that needs to be continuously monitored and controlled during handling, storage, and transportation to achieve repeatable and consistent CMP performances. Here, we investigated the effect of three different storage temperatures (15, 25, and 45oC) on several slurry health parameters (particle size, zeta potential, pH, total dissolved solids, conductivity, and dissolved oxygen (DO) concentration) of a ceria-based slurry and also on removal rates of SiO2 films during polishing. The changes in all the parameters of slurries stored at 15oC and 45oC for three weeks, except for DO concentration, were reversible and returned to their values at 25oC when the slurries were brought back to 25oC. DO concentration increased by ~14 % and decreased by ~18 % in the slurries stored for three weeks at 15oC and 45oC, respectively, compared to that of ceria slurry stored at 25oC. They did not return to the original values even after keeping them at 25oC for 6 hours. The increase in storage temperature causes an increase in the adsorption of dissolved oxygen onto the ceria surface, which can transform Ce3+ species into less reactive Ce4+-superoxo or a Ce3+-peroxo species, resulting in lower SiO2 removal rates.

Slow light photonic crystal waveguides (PCW) are a promising tool for optical signal processing as well as integrated optical devices that require strong light-matter interactions, such as modulators or non-linear devices. However, the low group velocity that characterizes these PCWs is typically accompanied by a large group velocity dispersion (GVD), and a low coupling efficiency. Improving both these properties for a large bandwidth forms the design challenge of most optical devices that rely on PCWs. In this work, we use inverse design methods to, firstly, design slow light PWCs with a large group index-bandwidth product (GBP), and secondly, to design couplers for the PCW, i.e. a mode converter, which couples a ridge waveguide to the PCW, and a grating coupler, which couples free space light directly to the PCW slow light mode. Both couplers are optimized for the PCW’s low group velocity dispersion bandwidth. Unlike pre-existing work, we perform the PCW optimization in full 3D simulations which result in more accurate and fully fabricable devices. The high degrees of freedom associated with inverse design makes it an effective method for these problems and, as such, an essential design tool to optimize future PCW applications.

We demonstrate a computational, optimization-based approach to inverse-design photonic devices meeting desired performance specifications. Several applications range from compact wavelength-demultiplexer devices to quantum optics and chip-scale LIDAR.

Miniaturizing particle accelerators Particle accelerators are usually associated with large national facilities. Because photons are able to impart momentum to electrons, there are also efforts to develop laser-based particle accelerators. Sapra et al. developed an integrated particle accelerator using photonic inverse design methods to optimize the interaction between the light and the electrons. They show that an additional kick of around 0.9 kilo–electron volts (keV) can be given to a bunch of 80-keV electrons along just 30 micrometers of a specially designed channel. Such miniaturized dielectric laser accelerators could open up particle physics to a number of scientific disciplines. Science , this issue p. 79

Due to their excellent optical properties, quantum dots are promising for applications in photonic quantum technologies. For on-demand single-photon generation, a two-level system given by an excitonic transition is typically excited with a resonant laser pulse of area π. This prepares the two-level system in its excited state from where it spontaneously emits a single photon. However, emission that occurs already during the presence of the laser pulse allows for re-excitation and, thus, multi-photon emission which limits the single-photon purity [1]. In contrast, when exciting the system with a pulse of area 2π, the system is expected to be returned to the ground state. However, in this case emission during the presence of the pulse is most likely to occur when the system is in its excited state – exactly after an area of π has been absorbed. This restarts the Rabi oscillation with a pulse area of π remaining in the pulse which leads to re-excitation with near-unity probability and the emission of a second photon within the excited state lifetime [2,3]. Finally, we present the generation of single photons with ultra-low multi-photon probability [4]. Using two-photon excitation of the bi-exciton suppresses re-excitation and improves the single photon purity by several orders of magnitude for short pulses. [1] K. A. Fischer, et al., New J. Phys. 18, 113053 (2016) [2] K. A. Fischer, et al., Nature Physics 13, 649-654 (2017) [3] K. A. Fischer, et al., Quantum Sci. Technol. 3, 014006 (2017) [4] L. Hanschke et al., arxiv: 1801.01672 (2018)

We use the scattering matrix formalism to analyze photon blockade in coherently driven cavity quantum electrodynamics systems with a weak drive. By approximating the weak coherent drive by an input single- and two-photon Fock state, we reduce the computational complexity of the transmission and the two-photon correlation function from exponential to polynomial in the number of emitters. This enables us to easily analyze cavity-based systems containing ∼50 quantum emitters with modest computational resources. Using this approach we study the coherence statistics of photon blockade while increasing the number of emitters for resonant and detuned multiemitter cavity quantum electrodynamics systems-we find that increasing the number of emitters worsens photon blockade in resonant systems, and improves it in detuned systems. We also analyze the impact of inhomogeneous broadening in the emitter frequencies on the photon blockade through this system.

We present the point-coupling Hamiltonian as a model for frequency-independent linear optical devices acting on propagating optical modes described as a continua of harmonic oscillators. We formally integrate the Heisenberg equations of motion for this Hamiltonian, calculate its quantum scattering matrix, and show that an application of the quantum scattering matrix on an input state is equivalent to applying the inverse of classical scattering matrix on the annihilation operators describing the optical modes. We show how to construct the point-coupling Hamiltonian corresponding to a general linear optical device described by a classical scattering matrix, and provide examples of Hamiltonians for some commonly used linear optical devices. Finally, in order to demonstrate the practical utility of the point-coupling Hamiltonian, we use it to rigorously formulate a matrix-product-state based simulation for time-delayed feedback systems wherein the feedback is provided by a linear optical device described by a scattering matrix as opposed to a hard boundary condition (e.g., a mirror with less than unity reflectivity).