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Metal oxide thin films are of great interest in scientific advancement, particularly semiconductor thin films in transistors and in a wide range of optoelectronic applications. Many metal oxide thin films attract interest for their electronic bandgap, charge carrier mobility, optical opacity, luminescence, low cost, relative abundance and environmentally-friendly production. Additionally, these properties are often tuneable via particle size, film density, surface morphology, film deposition, growth method, hetero-interface engineering or ion-doping. Zinc oxide as a n-type semiconducting metal oxide is material of great interest owing to its intrinsically wide direct bandgap, high electron mobility, relatively high exciton binding energy, high optical transparency, demonstrated metal-ion doping optoelectronic effects, a range of different particle morphologies and deposition methods, photoluminescence ability, low cost and a variety of existing green synthesis methods. Here, these aspects of zinc oxide and some related oxides are reviewed, focusing on how the unique properties of this metal oxide make it suitable for a range of different applications from thin film transistors, high mobility oxide interfaces, transparent conductive oxides, photoanodes photodetectors, chemical sensors, photocatalysts, superlattice electronics and more. The properties and deposition methods and their impact on functionality will be discussed alongside their role in sustainable optoelectronics for future devices., Comment: 72 pages, 22 figures

Cost-effective decarbonisation of the built environment is a stepping stone to achieving net-zero carbon emissions since buildings are globally responsible for more than a quarter of global energy-related CO$_2$ emissions. Improving energy utilization and decreasing costs naturally requires considering multiple domain-specific performance criteria. The resulting problem is often computationally infeasible. The paper proposes an approach based on decomposition and selection of significant operating conditions to achieve a formulation with reduced computational complexity. We present a robust framework to optimise the physical design, the controller, and the operation of residential buildings in an integrated fashion, considering external weather conditions and time-varying electricity prices. The framework explicitly includes operational constraints and increases the utilization of the energy generated by intermittent resources. A case study illustrates the potential of co-design in enhancing the reliability, flexibility and self-sufficiency of a system operating under different conditions. Specifically, numerical results demonstrate reductions in costs up to $30$% compared to a deterministic formulation. Furthermore, the proposed approach achieves a computational time reduction of at least $10$ times lower compared to the original problem with a deterioration in the performance of only 0.6%.

Zero-field optically pumped magnetometers (OPMs) have emerged as an important technology for biomagnetism due to their ulta-sensitive performance, contained within a non-cryogenic small-scale sensor-head. The compactness of such OPMs is often achieved through simplified detection schemes, which typically provide only single-axis magnetic field information. However, multi-axis static magnetic fields on non-measurement axes cause a systematic error that manifests as amplitude and phase errors across the measurement axis. Here we present a triaxial operational technique for a compact zero-field OPM which suppresses multi-axis systematic errors through simultaneous measurement and closed-loop active control of the static magnetic fields across all axes. The demonstrated technique requires magnetic modulation across two axes while providing static field information for all three axes. We demonstrate this technique on a rubidium laboratory-based zero-field magnetometer, achieving a bandwidth of 380 Hz with sensitivities of $<25$ fT/$\sqrt{\rm{Hz}}$ across both transverse axes and $65$ fT/$\sqrt{\rm{Hz}}$ along the beam axis. Using the proposed triaxial technique, we demonstrate precise tracking of a 2 Hz triaxial vector test signal and suppression of systematic cross-axis projection errors over an extended period, $\simeq20$~min.

The influence of thickness gradient and structural order on the spectral response of opal photonic crystals (PhCs) grown by evaporation-induced self-assembly (EISA) are presented. SEM imaging and angle resolved optical transmission spectroscopy are used to investigate the evolution of the PBG along a thickness gradient for opals grown from five different colloidal sphere concentrations at two different evaporation rates. The degradation of structural order along the thickness gradient is demonstrated, the occurrence of which attenuates the PBG with the thinning of the opal film and results in asymmetrical angle-resolved transmission spectra. The asymmetry in transmission intensity becomes more pronounced for opals grown from lower volume fractions, where secondary Bragg reflections also appear at low incident angles., Comment: 9 pages, 4 figures

In previous work, a lattice scalar propagator was rigorously defined in $d=1$ flat space and shown to equal the known Klein-Gordon propagator of QFT. This work generalizes this lattice propagator to manifolds whose universal cover is the hyperbolic half plane as well as a broad class of higher dimensional manifolds. We motivate a conjecture for the power spectrum of these curved space propagators. Afterwards, an analogous definition of the Dirac spinor propagator is defined. The formulation of these propagators are unified by the understanding of the object as a Fourier transform of the volume of path space of paths with the same length $I$ to mass $m$; the main theorem of this work will be to demonstrate that the point correlators of scalar peturbative QFT can be understood as a Fourier transform of the volume of path space of paths, which realize a Feynman diagram and have some total length I. After demonstrating this theorem, the author goes on to conjecture the point correlators of the Abelian Higgs Model in this geometric formulation., Comment: 27 pages, 4 figures

I define the lattice propagator on a very general collection of graphs, namely graphs locally isomorphic to $\mathbb{Z}^{d}\times \mathbb{Z}$. I then define polygonal approximations to the minkowski metric and define a corresponding lattice propagator for these. I show in $d=1$, as suggested by the metric approximation, the continuum limit of the polygonal propagators converges to the Klien Gordon Propagator. Finally, I obtain the taxicab polygonal propagator in a very general collection of spaces, including $\mathbb{T}^{d}$, the Klein bottle, and a discretization of de-Sitter space., Comment: 31 pages, 7 figures

The Light Dark Matter eXperiment (LDMX) is an electron-beam fixed-target experiment designed to achieve comprehensive model independent sensitivity to dark matter particles in the sub-GeV mass region. An upgrade to the LCLS-II accelerator will increase the beam energy available to LDMX from 4 to 8 GeV. Using detailed GEANT4-based simulations, we investigate the effect of the increased beam energy on the capabilities to separate signal and background, and demonstrate that the veto methodology developed for 4 GeV successfully rejects photon-induced backgrounds for at least $2\times10^{14}$ electrons on target at 8 GeV., Comment: 28 pages, 20 figures; corrected author list

We investigate the spatial characteristics of high-order harmonic radiation generated in argon, and observe cross-like patterns in the far field. An analytical model describing harmonics from an astigmatic driving beam reveals that these patterns result from the order and generation position dependent divergence of harmonics. Even small amounts of driving field astigmatism may result in cross-like patterns, coming from the superposition of individual harmonics with spatial profiles elongated in different directions. By correcting the aberrations using a deformable mirror, we show that fine-tuning the driving wavefront is essential for optimal spatial quality of the harmonics.

In this article, we present a hybrid quantum-classical generative adversarial network (GAN) for near-term quantum processors. The hybrid GAN comprises a generator and a discriminator quantum neural network (QNN). The generator network is realized using an angle encoding quantum circuit and a variational quantum ansatz. The discriminator network is realized using multi-stage trainable encoding quantum circuits. A modular design approach is proposed for the QNNs which enables control on their depth to compromise between accuracy and circuit complexity. Gradient of the loss functions for the generator and discriminator networks are derived using the same quantum circuits used for their implementation. This prevents the need for extra quantum circuits or auxiliary qubits. The quantum simulations are performed using the IBM Qiskit open-source software development kit (SDK), while the training of the hybrid quantum-classical GAN is conducted using the mini-batch stochastic gradient descent (SGD) optimization on a classic computer. The hybrid quantum-classical GAN is implemented using a two-qubit system with different discriminator network structures. The hybrid GAN realized using a five-stage discriminator network, comprises 63 quantum gates and 31 trainable parameters, and achieves the Kullback-Leibler (KL) and the Jensen-Shannon (JS) divergence scores of 0.39 and 0.52, respectively, for similarity between the real and generated data distributions.

Innovative new materials are consistently emerging as electrode candidates from lithium-ion battery research, promising high energy densities and high-rate capabilities. Understanding potential structural changes, morphology evolution, degradation mechanisms and side reactions during lithiation is important for designing, optimising and assessing aspiring electrode materials. In-situ and operando analysis techniques provide a means to investigate these material properties under realistic operating conditions. Here, we demonstrate an operando spectroscopic method using photonic crystal-structured electrodes that uses the optical transmission spectrum to monitor changes to the state of charge or discharge during lithiation and the change to electrode structure, in real-time. Photonic crystals possess a signature optical response, with a photonic bandgap (or stopband) presenting as a structural colour reflection from the material. We leverage the presence of this photonic stopband, alongside its intricate relationship to the electrode structure and material phase, to correlate electrode lithiation with changes to the optical spectrum during operation. In this work, we explore the optical and electrochemical behaviour of a TiO2 anode in a lithium-ion battery, structured as an inverse opal photonic crystal. In principle, the operando technique demonstrated here is versatile and applicable to a wide range of electrochemical electrode material candidates when structured with ordered porosity akin to a photonic crystal structure., Comment: 40 pages, 16 figures with Supplementary information

Opals are naturally occurring photonic crystals which can be formed easily using low-cost self-assembly methods. While the optical behaviour of opals has received significant attention over the last number of decades, there is limited information on the effect of crystal thickness on the optical properties they display. Here, the relationship between volume fraction and crystal thickness is established with an evaporation-induced self-assembly (EISA) method of formation. The extent to which thickness can be used to manipulate the optical properties of the crystals is explored, focusing on the change in the photonic band gap (PBG). Microscopical structural characterization and angle-resolved transmission spectroscopy are used to examine the quality of the photonic crystals formed using different volume fractions of polystyrene spheres, with thicknesses up to 37 layers grown from volume fractions of 0.125%. This work provides a direct correlation between sphere solution volume fraction and crystal thickness, and the associated optical fingerprint of opal photonic crystals. Maximum thickness is examined, which is shown to converge to a narrow range over several evaporation rates. We identify the criteria required to achieve thickness control in relatively fast evaporation induced self-assembly while maintaining structural quality, and the change to the spectroscopic signature to the (111) stopband and higher order (220) reflections, under conditions where a less ordered photonic crystals are formed., Comment: 29 pages with Supplementary materials, 9 figures and 1 table

Existing methods for nonlinear robust control often use scenario-based approaches to formulate the control problem as large nonlinear optimization problems. The optimization problems are challenging to solve due to their size, especially if the control problems include time-varying uncertainty. This paper draws from local reduction methods used in semi-infinite optimization to solve robust optimal control problems with parametric and time-varying uncertainty. By iteratively adding interim worst-case scenarios to the problem, methods based on local reduction provide a way to manage the total number of scenarios. We show that the local reduction method for optimal control problems consists of solving a series of simplified optimal control problems to find worst-case constraint violations. In particular, we present examples where local reduction methods find worst-case scenarios that are not on the boundary of the uncertainty set. We also provide bounds on the error if local solvers are used. The proposed approach is illustrated with two case studies with parametric and additive time-varying uncertainty. In the first case study, the number of scenarios obtained from local reduction is 101, smaller than in the case when all $2^{14+3\times192}$ extreme scenarios are considered. In the second case study, the number of scenarios obtained from the local reduction is two compared to 512 extreme scenarios. Our approach was able to satisfy the constraints both for parametric uncertainty and time-varying disturbances, whereas approaches from literature either violated the constraints or became computationally expensive., Comment: arXiv admin note: substantial text overlap with arXiv:2204.14145 (IFAC conference submission)

The specific activity of the beta decay of $^{39}$Ar in atmospheric argon is measured using the DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total of (3269 $\pm$ 24) kg of liquid argon distilled from the atmosphere to search for dark matter. This detector with very low background uses pulseshape discrimination to differentiate between nuclear recoils and electron recoils and is well-suited to measure the decay of $^{39}$Ar. With 167 live-days of data, the measured specific activity at the time of atmospheric extraction is [0.964 $\pm$ 0.001 (stat) $\pm$ 0.024 (sys)] Bq/kg$_{\rm atmAr}$ which is consistent with results from other experiments. A cross-check analysis using different event selection criteria provides a consistent result.

New York State is experiencing teacher shortages in specific subject areas. One way to address these shortages is through the certification and placement of new teachers. This study explored the pathways through which new teachers between 2015/16 and 2017/18 earned certificates, their certification areas, and their subsequent placement and retention in districts across the state, particularly high-need districts. While the majority of new teachers earned certificates through the traditional in-state pathway, this varied somewhat by certification area. The proportion of teachers who earned certificates through the individual evaluation pathway was higher for the shortage certification area of career and technical education than for other certification areas. The most frequent certification area was the shortage certification area of special education, while the shortage certification areas of career and technical education and bilingual special education were among the least frequent. New York City district schools employed new teachers who earned certificates through the alternative in-state pathway at a higher rate than other types of high-need districts (rural, large city--not New York City, and other urban/suburban) as well as average- and low-need districts. New teachers employed in high-need districts had higher rates of retention in the same district for a second year than new teachers employed in average- and low-need districts. Just 5 percent of new teachers in New York State were uncertified. [For the full report, see ED615881. For the Study Snapshot, see ED615882. For the appendixes, see ED615884.]

New York State is experiencing teacher shortages in specific subject areas. One way to address these shortages is through the certification and placement of new teachers. This study explored the pathways through which new teachers between 2015/16 and 2017/18 earned certificates, their certification areas, and their subsequent placement and retention in districts across the state, particularly high-need districts. While the majority of new teachers earned certificates through the traditional in-state pathway, this varied somewhat by certification area. The proportion of teachers who earned certificates through the individual evaluation pathway was higher for the shortage certification area of career and technical education than for other certification areas. The most frequent certification area was the shortage certification area of special education, while the shortage certification areas of career and technical education and bilingual special education were among the least frequent. New York City district schools employed new teachers who earned certificates through the alternative in-state pathway at a higher rate than other types of high-need districts (rural, large city--not New York City, and other urban/suburban) as well as average- and low-need districts. New teachers employed in high-need districts had higher rates of retention in the same district for a second year than new teachers employed in average- and low-need districts. Just 5 percent of new teachers in New York State were uncertified. [For the Study Brief, see ED615883. For the Study Snapshot, see ED615882. For the appendixes, see ED615884.]

Chicago Public Schools is working to improve early literacy outcomes through a multiyear professional development initiative for preK-2 teachers. The P-2 Balanced Literacy Initiative aims to improve literacy instruction by training teachers to implement effective early literacy instruction balancing systematic foundational skills instruction with reading and writing instruction involving rich, complex texts. The study compared the reading achievement of students who attended schools that received the enhanced supports (priority schools) with the reading achievement of students who attended similar schools that received only the initiative's standard supports (nonpriority schools). It also examined differences between priority and nonpriority schools in teachers' and administrators' participation in professional development sessions and looked at the successes and challenges of implementation. The study found that one year after implementation of the initiative, attending a priority school did not lead to higher end-of-year reading achievement than attending a nonpriority school after other factors were adjusted for. Teachers and administrators in priority schools were more likely than those in nonpriority schools to participate in the initiative's core professional development sessions. This Study Brief to the full report presents: (1) Why this study?; (2) What was studied and how?; (3) Findings; and (4) Implications. [For the full report, see ED617588. For the Study Snapshot, see ED617589. For the appendixes, see ED617591.]

Chicago Public Schools is working to improve early literacy outcomes through a multiyear professional development initiative for preK-2 teachers. The P-2 Balanced Literacy Initiative aims to improve literacy instruction by training teachers to implement effective early literacy instruction balancing systematic foundational skills instruction with reading and writing instruction involving rich, complex texts. The initiative began in 2016/17 and served 23 percent of all district elementary schools by 2018/19. The district designated 26 of the 115 elementary schools implementing the initiative in 2018/19 to receive enhanced supports, including intensive, site-based coaching, to support students' independent reading. This study compared the reading achievement of students who attended schools that received the enhanced supports (priority schools) with the reading achievement of students who attended similar schools that received only the initiative's standard supports (nonpriority schools). It also examined differences between priority and nonpriority schools in teachers' and administrators' participation in professional development sessions and looked at the successes and challenges of implementation. The study found that one year after implementation of the initiative, attending a priority school did not lead to higher end-of-year reading achievement than attending a nonpriority school after other factors were adjusted for. Teachers and administrators in priority schools were more likely than those in nonpriority schools to participate in the initiative's core professional development sessions. Interviews with select district, network, and school leaders; instructional support coaches; and teachers suggest that several aspects of the initiative's professional development were valuable, most notably the opportunities for teachers to deepen their understanding of the initiative's professional development, receive feedback through observation and school-based coaching, and learn from one another. But instructional support coaches' limited capacity, due to competing responsibilities, was a challenge. District leaders might consider increasing the number of coaches available and limiting their competing priorities so they can focus on the initiative. [For the Study Brief, see ED617590. For the Study Snapshot, see ED617589. For the appendixes, see ED617591.]

The growth of complex populations, such as microbial communities, forests, and cities, occurs over vastly different spatial and temporal scales. Although research in different fields has developed detailed, system-specific models to understand each individual system, a unified analysis of different complex populations is lacking; such an analysis could deepen our understanding of each system and facilitate cross-pollination of tools and insights across fields. Here, for the first time we use a shared framework to analyze time-series data of the human gut microbiome, tropical forest, and urban employment. We demonstrate that a single, three-parameter model of stochastic population dynamics can reproduce the empirical distributions of population abundances and fluctuations in all three data sets. The three parameters characterizing a species measure its mean abundance, deterministic stability, and stochasticity. Our analysis reveals that, despite the vast differences in scale, all three systems occupy a similar region of parameter space when time is measured in generations. In other words, although the fluctuations observed in these systems may appear different, this difference is primarily due to the different physical timescales associated with each system. Further, we show that the distribution of temporal abundance fluctuations is described by just two parameters and derive a two-parameter functional form for abundance fluctuations to improve risk estimation and forecasting.

Big pores, small pores, ordered pores, random pores, they all have a function and as is often found, show behaviour in new materials that is not always predicted or obvious at the outset. I started my research journey trying to put extremely thin films onto near-perfect III-V crystals to control (opto)electronic properties and when the first TEM on our campus showed remarkable pore growth and structure in InP almost 21 years ago, the electrochemical modification of the InP made more sense. In this paper, I will summarise a few aspects of research into porous materials and semiconductors, from porous InP that led to studies of other porous semiconductors such as silicon, GaN, ZnO and Indium Tin oxide (ITO), to periodically ordered photonic crystal porous structures and some optical, thermal and electrochemical properties, photocatalysis, studies in batteries and related that were enabled or modified by the porous structure., Comment: 22 pages, 14 figures

The ability to selectively redirect specific wavelengths of light has attracted a lot attention for photonic crystal materials. Presently, there is a wealth of research relating to the fabrication and application of photonic crystal materials. There a number of structures which fallinto the category of a photonic crystal; 1D, 2D and 3D ordered structures can qualify as a photonic crystal, provided there exists ordered repeating lattices of dielectric material with a sufficient refractive index contrast. The optical responses of these structures, namely the associated photonic bandgap or stopband, are of particular interest for any application involving light. The sensitivity of the photonic bandgap to changes in lattice size or refractive index composition creates the possibility foraccurate optical sensors. Optical phenomena involving reduced group velocity at wavelengths on the edge of the photonic bandgap are commonly exploited for photocatalytic applications. The inherent reflectivity of the photonic bandgap has created applications in optical waveguides or as solar cell reflector layers. There are countless examples of research attempting to exploit these facets of photonic crystal behaviorfor improved material design. Here, the role of photonic crystals is reviewed across a wide a variety of disciplines; cataloguing the ways in which these structures have enhanced specific applications. Particular emphasis is placed on providing an understanding of the specific function of the tunable optical response in photonic crystals in relation to their application., Comment: 96 pages, 30 figures

The SPectrogram Analysis and Cataloguing Environment (SPACE) tool is an interactive python tool designed to label radio emission features of interest in a time-frequency map (called 'dynamic spectrum'). The program uses Matplotlib's Polygon Selector widget to allow a user to select and edit an undefined number of vertices on top of the dynamic spectrum before closing the shape (polygon). Multiple polygons may be drawn on any spectrum, and the feature name along with the coordinates for each polygon vertex are saved into a '.json' file as per the 'Time-Frequency Catalogue' (TFCat) format along with other data such as the feature id, observer name, and data units. This paper describes the first official stable release (version 2.0) of the tool., Comment: 9 pages, 1 Figure

With the importance of Li-ion and emerging alternative batteries to our electric future, predicting new sustainable materials, electrolytes and complete cells that safely provide high performance, long life, energy dense capability is critically important. Understanding interface, microstructure of materials, the nature of electrolytes and factors that affect or limit long term performance are key to new battery chemistries, cell form factors and alternative materials. The electrochemical processes which cause these changes are also difficult to probe because of their metastability and lifetimes, which can be of nanosecond to sub nanosecond time domains. Consequently, developing and adapting high-resolution, non-destructive methods to capture these processes proves challenging, requiring state-of-the-art techniques.Recent progress is very promising, where optical spectroscopies, synchrotron radiation techniques, and energy-specific atom probe tomography and microscopy methods are just some of the approaches that are unravelling the true internal behaviour of battery cells in real-time.In this review, we overview many of the most promising non-destructive methods developed in recent years to assess battery material properties, interfaces, processes,and reactions under operando conditions in electrodes and full cells., Comment: 53 pages, 21 figures