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We construct a lattice field theory method for computing the real-time dynamics of spin systems in a thermal bath. This is done by building on previous work of Takano with Schwinger-Keldysh and functional differentiation techniques. We derive a Schwinger-Keldysh path integral for generic spin Hamiltonians, then demonstrate the method on a simple system. Our path integral has a sign problem, which generally requires exponential run time in the system size, but requires only linear storage. The latter may place this method at an advantage over exact diagonalization, which is exponential in both. Our path integral is amenable to contour deformations, a technique for reducing sign problems. [ABSTRACT FROM AUTHOR]

A key step toward demonstrating a quantum system that can address difficult problems in physics and chemistry will be performing a computation beyond the capabilities of any classical computer, thus achieving so-called quantum supremacy. In this study, we used nine superconducting qubits to demonstrate a promising path toward quantum supremacy. By individually tuning the qubit parameters, we were able to generate thousands of distinct Hamiltonian evolutions and probe the output probabilities. The measured probabilities obey a universal distribution, consistent with uniformly sampling the full Hilbert space. As the number of qubits increases, the system continues to explore the exponentially growing number of states. Extending these results to a system of 50 qubits has the potential to address scientific questions that are beyond the capabilities of any classical computer. [ABSTRACT FROM AUTHOR]

Quantized eigenenergies and their associated wave functions provide extensive information for predicting the physics of quantum many-body systems. Using a chain of nine superconducting qubits, we implement a technique for resolving the energy levels of interacting photons. We benchmark this method by capturing the main features of the intricate energy spectrum predicted for two-dimensional electrons in a magnetic field—the Hofstadter butterfly. We introduce disorder to study the statistics of the energy levels of the system as it undergoes the transition from a thermalized to a localized phase. Our work introduces a many-body spectroscopy technique to study quantum phases of matter. [ABSTRACT FROM AUTHOR]

Three experiments were conducted to evaluate the feeding of dried distillers' grains with solubles (DDGS) in sow lactation diets. In Exp. 1, 168 multiparous sows (PIC, Camborough 22) were fed a 10% DDGS diet throughout gestation. Sows were randomly allotted to 1 of 4 corn-soybean meal lactation diets formulated to contain different levels of DDGS (0, 10, 20, and 30%, respectively). All diets were formulated to be isocaloric (3.46 Mcal ME/kg) and all other nutrients exceeded NRC (1998) nutrient recommendations. Sow ADFI was not different (P > 0.10) as DDGS level increased. Increasing DDGS resulted in a linear (P < 0.03) increase in sow weight gain (7.5, 11.3, 20.3, and 17.2 kg, respectively) and a reduction in wean-to-first-service interval (7.1, 5.2, 5.0, and 4.9 d, respectively). Increasing DDGS did not affect subsequent total born per litter (13.7, 12.8, 13.3, and 12.3, respectively; P > 0.10). In Exp. 2 and 3, lactation diets consisted of corn and 20, 30, 40, or 50% DDGS. Diets were formulated at 3.25 Mcal ME/kg, 1.05% standardized ileal digestible lysine, and all other nutrients to exceed NRC (1998) nutrient recommendations. In both experiments, sows (PIC, Camborough) were fed 40% DDGS in gestation and allocated to a randomized complete block based on the parity of the sow at the time of entry into the farrowing house. In Exp. 2, 256 gilts and multiparous sows were fed the randomly assigned diets. As DDGS inclusion increased, sow feed intake (6.2, 6.2, 6.0, and 5.9 kg/d, respectively) and sow weight gain (10.5, 10.3, 8.2, and 6.2 kg, respectively) tended to linearly decrease (P < 0.06). Sow wean to estrus differed between 20 and 30% DDGS inclusion (4.9 vs. 6.9 d; P < 0.01). Litter gain was not different (2.55, 2.53, 2.51, and 2.59 kg/d, respectively; P > 0.10) as DDGS inclusion increased. In Exp. 3, 98 multiparous sows were randomly allotted to 1 of the 4 experimental diets during the summer months. Sow feed intake, sow weight gain, and litter gain were not different (P > 0.10) between treatments. The data suggest that feeding high levels of DDGS of 40 to 50% may reduce sow feed intake and litter performance. These results demonstrate that feeding up to 30% DDGS in lactation diets can be done without adversely influencing sow or litter performance. [ABSTRACT FROM AUTHOR]

We introduce a superconducting qubit architecture that combines high-coherence qubits and tunable qubit-qubit coupling. With the ability to set the coupling to zero, we demonstrate that this architecture is protected from the frequency crowding problems that arise from fixed coupling. More importantly, the coupling can be tuned dynamically with nanosecond resolution, making this architecture a versatile platform with applications ranging from quantum logic gates to quantum simulation. We illustrate the advantages of dynamical coupling by implementing a novel adiabatic controlled-z gate, with a speed approaching that of single-qubit gates. Integrating coherence and scalable control, the introduced qubit architecture provides a promising path towards large-scale quantum computation and simulation. [ABSTRACT FROM AUTHOR]

Topology, with its abstract mathematical constructs, often manifests itself in physics and has a pivotal role in our understanding of natural phenomena. Notably, the discovery of topological phases in condensed-matter systems has changed the modern conception of phases of matter. The global nature of topological ordering, however, makes direct experimental probing an outstanding challenge. Present experimental tools are mainly indirect and, as a result, are inadequate for studying the topology of physical systems at a fundamental level. Here we employ the exquisite control afforded by state-of-the-art superconducting quantum circuits to investigate topological properties of various quantum systems. The essence of our approach is to infer geometric curvature by measuring the deflection of quantum trajectories in the curved space of the Hamiltonian. Topological properties are then revealed by integrating the curvature over closed surfaces, a quantum analogue of the Gauss-Bonnet theorem. We benchmark our technique by investigating basic topological concepts of the historically important Haldane model after mapping the momentum space of this condensed-matter model to the parameter space of a single-qubit Hamiltonian. In addition to constructing the topological phase diagram, we are able to visualize the microscopic spin texture of the associated states and their evolution across a topological phase transition. Going beyond non-interacting systems, we demonstrate the power of our method by studying topology in an interacting quantum system. This required a new qubit architecture that allows for simultaneous control over every term in a two-qubit Hamiltonian. By exploring the parameter space of this Hamiltonian, we discover the emergence of an interaction-induced topological phase. Our work establishes a powerful, generalizable experimental platform to study topological phenomena in quantum systems. [ABSTRACT FROM AUTHOR]

We describe the fabrication and measurement of microwave coplanar waveguide resonators with internal quality factors above 107 at high microwave powers and over 106 at low powers, with the best low power results approaching 2×106, corresponding to ∼1 photon in the resonator. These quality factors are achieved by controllably producing very smooth and clean interfaces between the resonators' aluminum metallization and the underlying single crystal sapphire substrate. Additionally, we describe a method for analyzing the resonator microwave response, with which we can directly determine the internal quality factor and frequency of a resonator embedded in an imperfect measurement circuit. [ABSTRACT FROM AUTHOR]

Carolyn Neill and Una Hughes report on how a paediatric benchmarking group in Northern Ireland has improved the quality of care during transfer of critically ill children. [ABSTRACT FROM AUTHOR]

We introduce a theoretical framework to analyze the thermal properties of a recently proposed "excluded volume" model of quarkyonic matter. This entails proposing finite temperature distribution functions and entropy functionals constrained by internal theoretical consistency. We use the formalism developed here to analyze the effect of temperature on the quark onset as a function of baryon density. We find that the baryon density at which the quarkyonic phase emerges decreases only slightly with temperature, an effect produced by large N c. We furthermore find that a finite temperature increases the density of quarks produced. The framework presented here can be used to compute the equation of state of hot and dense quarkyonic matter which is of relevance to neutron star mergers. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the Standardized Ileal Digestible (SID) threonine:lysine ratio on nursery pigs performance under commercial conditions. A total of 2,262 pigs (PIC 359×Camborough®, 5.7 ± 0.1 kg) were used in a 39-d trial. Pens were assigned to dietary treatments in a randomized complete block based on initial BW and room (13 pens/treatment). Lysine was kept below the requirement to ensure that the Thr:Lys ratio was not underestimated (1.30, 1.30, 1.25, and 1.15% SID Lys for 5.7 to 6.4, 6.4 to 9.1, 9.1 to 12.2, and 12.2 to 18.8 kg, respectively). Dietary treatments were 53, 56, 59, 62, 65, and 68% SID Thr:Lys and were fed throughout the entire study. The levels of zinc oxide in the first and second diet were 1600 and 800 mg/kg, respectively. Diet analysis matched formulated values. Data was analyzed using the MIXED procedure of SAS. Linear and quadratic polynomial contrasts were used to evaluate the dose response effect. BW and room were considered random effects in the models. The NLMIXED procedure was used to evaluate competing models: linear (LN), quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). From 0 to 21 d, ADG and G:F increased (linear, P = 0.016) with the increase in SID Thr:Lys, whereas ADFI and BW were not statistically affected (P = 0.236). From d 21 to 39, G:F increased (quadratic, P = 0.006) with the increase in SID Thr:Lys. However, ADG, ADFI, and BW were not statistically different (P = 0.179) between treatments. Overall, G:F increased significantly (quadratic, P = 0.001) and ADG was not statistically different (P = 0.103) as SID Thr:Lys increased, whereas ADFI was not statistically different (P = 0.236). Based on the dose-response estimation models with the best fit, the levels that maximized performance were >68% for ADG [LN; (ADG=0.64686 + 0.0014932×SID Thr:Lys)/2.2046] and 65% for G:F [QP; G:F=1/(3.56512–0.0661676×SID Thr:Lys+0.0005089×(SID Thr:Lys)2)]. In conclusion, formulating diets to 65% SID Thr:Lys should maximize G:F while capturing 99.4% of ADG. SID Threonine:Lysine SEM 53 56 59 62 65 68 d 0 to 39 ADGa, g 327 336 331 340 331 345 10.4 ADFI, g 490 481 476 481 472 485 16.8 G:Fb 0.667 0.685 0.694 0.699 0.699 0.699 0.008 BW, kg d 0 5.6 5.7 5.6 5.7 5.7 5.6 0.13 d 39 18.5 18.7 18.7 19 18.6 19.1 0.45 aLinear,P=0.103. bQuadratic, P=0.001. [ABSTRACT FROM AUTHOR]

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chainÕs center, P M Þ. The ð first two moments of P M Þ show superdiffusive behavior, a hallmark of KPZ universality. However, the ð third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems. [ABSTRACT FROM AUTHOR]

Nutrient requirements are primarily determined for a growth phase and mean population without considering population variation and important variables that define population response. For lysine curves to be financially useful, responses must be established using multiple criteria and equations must be developed for financial modeling. This study defined the response to 4 standardized ileal digestible (SID) lysine curves using 6 population growth (whole-body and carcass) and carcass primal parameters. A total of 2048 pigs (PIC Cambor-ough x TR-4 or 327) were used in a growth assay from 20.4 ( ± 0.3 kg) to 119.0 ( ± 1.1 kg) with a fixed-time end point (110 d). Pigs were placed in 65 pens (30 to 32 pigs/pen and 0.70 m2/pig), blocked by BW, and randomly allotted within gender and genotype to 4 dietary treatments administered in 5 phases of growth (20 kg BW phases). Dietary treatments corresponded to 4 different SID lysine curves that deviated from the 2008 PIC lysine specifications. Curves were 92, 98, 104, and 110% of the PIC standard lysine curve {SID lysine:ME [g SID lysine/Mcal ME (NRC, 1998)] = (2.7 x 10-5 x BW2) - (0.0153 x BW) + 4.114)}. Diets were corn-soybean meal based with 15.0% corn distiller's dried grains with solubles and 2.7% choice white grease as a fat source. Major ingredients were constant within diet phase, but crystalline AA were adjusted as required. Feed medication and ractopamine were not used. Data were analyzed as a randomized complete block design with pen as the experimental unit. Whole-body ADG improved as lysine increased (quadratic, P = 0.02; 0.82, 0.85, 0.83, and 0.82 kg/dforthe 92, 98, 104, and 110% curves, respectively) as did G:F (quadratic, P < 0.001; 0.399, 0.418, 0.425, and 0.418 for the 92, 98, 104, and 110% curves, respectively). Likewise, carcass G:F improved as lysine increased (linear, P < 0.001; 0.294, 0.303, 0.308, and 0.308 for the 92, 98, 104, and 110% curves, respectively). The effect of increasing lysine on population growth was reflected by the reduction of the proportion of pigs sold as substandard (quadratic, P = 0.014; 6.5, 3.7, 2.8, and 4.3% for the 92, 98, 104, and 110% curves, respectively), which improved full-value market pigs (quadratic, P = 0.008, 91.2, 94.6, 95.3, and 92.9% for the 92, 98, 104, and 110% curves, respectively). Carcass lean increased as lysine increased (linear, P = 0.011; 52.5, 52.6, 52.6, and 52.8% for the 92, 98, 104, and 110% curves, respectively) as did the primal yield (n = 309) relative to a 98.2-kg carcass, with the latter being identical in response form to other criteria (linear, P = 0.037; 87.5, 87.7, 88.0, and 87.9% for the 92, 98, 104, and 110% curves, respectively). This study determined the lysine curve on a population basis, using criteria not captured in interval studies. Response asymptote for each criterion was achieved at 104% of the 2008 PIC lysine requirement. [ABSTRACT FROM AUTHOR]

Superconducting resonators, used in astronomy and quantum computation, couple strongly to microscopic two-level defects. We monitor the microwave response of superconducting resonators and observe fluctuations in dissipation and resonance frequency. We present a unified model where the observed dissipative and dispersive effects can be explained as originating from a bath of fluctuating two-level systems. From these measurements, we quantify the number and distribution of the defects. [ABSTRACT FROM AUTHOR]

This paper presents a stochastic performance modelling approach that can be used to optimise design and operational reliability of complex chemical engineering processes. The framework can be applied to processes comprising multiple units, including the cases where closed form process performance functions are unavailable or difficult to derive from first principles, which is often the case in practice. An interface that facilitates automated two-way communication between Matlab ® and process simulation environment is used to generate large process responses. The resulting constrained optimisation problem is solved using both Monte Carlo Simulation (MCS) and First Order Reliability Method (FORM); providing a wide range of stochastic process performance measures. Adding such capabilities to traditional deterministic process simulators provides a more informed basis for selecting optimum design factors; giving a simple way of enhancing overall process reliability and cost-efficiency. Two case study systems are considered to highlight the applicability and benefits of the approach. [ABSTRACT FROM AUTHOR]

Abstract: The effect of ageing temperature and holding time on the precipitation of secondary phases and the mechanical properties of a 25Cr–6.7Ni–0.32N–3.0Mo–2.5W super duplex stainless steel is examined. The ageing temperature was varied from 600 to 900°C and the holding time was varied from 1 to 240min. Two types of Cr and Mo enriched intermetallic phases, sigma (σ) and chi (χ), were found to precipitate preferentially at the ferrite/austenite interface and within the ferrite grain. The precipitation of the χ-phase occurred preferentially before the σ-phase. The concentration of these secondary phases, which was quantified by a combination of microscopy and image analysis, increases with increasing ageing temperature and holding time, leading to significant reduction in the uniform strain and enhancement of the modulus, hardness and yield and tensile strengths. The measured concentration of the precipitated sigma phase is in agreement with the prediction by the Johnson–Mehl–Avrami kinetic model. [Copyright &y& Elsevier]

Josephson junctions form the essential non-linearity for almost all superconducting qubits. The junction is formed when two superconducting electrodes come within ∼1 nm of each other. Although the capacitance of these electrodes is a small fraction of the total qubit capacitance, the nearby electric fields are more concentrated in dielectric surfaces and can contribute substantially to the total dissipation. We have developed a technique to experimentally investigate the effect of these electrodes on the quality of superconducting devices. We use λ/4 coplanar waveguide resonators to emulate lumped qubit capacitors. We add a variable number of these electrodes to the capacitive end of these resonators and measure how the additional loss scales with the number of electrodes. We then reduce this loss with fabrication techniques that limit the amount of lossy dielectrics. We then use these techniques for the fabrication of Xmon qubits on a silicon substrate to improve their energy relaxation times by a factor of 5. [ABSTRACT FROM AUTHOR]

Human drivers are often proposed to be stronger than biophysical drivers in influencing ecosystem structure and function in highly urbanized areas. In residential land cover, private yards are influenced by individual homeowner preferences and actions while also experiencing large-scale human and biophysical drivers. We studied plant nitrogen (%N) and N stable isotopic composition (δN) in residential yards and paired native ecosystems in seven cities across the US that span major ecological biomes and climatic regions: Baltimore, Boston, Los Angeles, Miami, Minneapolis-St. Paul, Phoenix, and Salt Lake City. We found that residential lawns in three cities had enriched plant δN ( P < 0.03) and in six cities higher plant N (%) relative to the associated native ecosystems ( P < 0.05). Plant δN was progressively depleted across a gradient of urban density classes in Baltimore and Boston ( P < 0.05). Lawn fertilization was associated with depleted plant δN in Boston and Los Angeles ( P < 0.05), and organic fertilizer additions were associated with enriched plant δN in Los Angeles and Salt Lake City ( P < 0.04). Plant δN was significantly enriched as a function of housing age in Baltimore ( r = 0.27, P < 0.02), Boston ( r = 0.27, P < 0.01), and Los Angeles ( r = 0.34, P < 0.01). These patterns in plant δN and plant N (%) across these cities suggests that N sources to lawns, as well as greater rates of N cycling combined with subsequent N losses, may be important drivers of plant N dynamics in lawn ecosystems at the national scale. [ABSTRACT FROM AUTHOR]

Josephson parametric amplifiers have become a critical tool in superconducting device physics due to their high gain and quantum-limited noise. Traveling wave parametric amplifiers (TWPAs) promise similar noise performance, while allowing for significant increases in both bandwidth and dynamic range. We present a TWPA device based on an LC-ladder transmission line of Josephson junctions and parallel plate capacitors using low-loss amorphous silicon dielectric. Crucially, we have inserted λ/4 resonators at regular intervals along the transmission line in order to maintain the phase matching condition between pump, signal, and idler and increase gain. We achieve an average gain of 12 dB across a 4 GHz span, along with an average saturation power of 92 dBm with noise approaching the quantum limit. [ABSTRACT FROM AUTHOR]

Quantum computing becomes viable when a quantum state can be protected from environment-induced error. If quantum bits (qubits) are sufficiently reliable, errors are sparse and quantum error correction (QEC) is capable of identifying and correcting them. Adding more qubits improves the preservation of states by guaranteeing that increasingly larger clusters of errors will not cause logical failure-a key requirement for large-scale systems. Using QEC to extend the qubit lifetime remains one of the outstanding experimental challenges in quantum computing. Here we report the protection of classical states from environmental bit-flip errors and demonstrate the suppression of these errors with increasing system size. We use a linear array of nine qubits, which is a natural step towards the two-dimensional surface code QEC scheme, and track errors as they occur by repeatedly performing projective quantum non-demolition parity measurements. Relative to a single physical qubit, we reduce the failure rate in retrieving an input state by a factor of 2.7 when using five of our nine qubits and by a factor of 8.5 when using all nine qubits after eight cycles. Additionally, we tomographically verify preservation of the non-classical Greenberger-Horne-Zeilinger state. The successful suppression of environment-induced errors will motivate further research into the many challenges associated with building a large-scale superconducting quantum computer. [ABSTRACT FROM AUTHOR]

Many superconducting qubits are highly sensitive to dielectric loss, making the fabrication of coherent quantum circuits challenging. To elucidate this issue, we characterize the interfaces and surfaces of superconducting coplanar waveguide resonators and study the associated microwave loss. We show that contamination induced by traditional qubit lift-off processing is particularly detrimental to quality factors without proper substrate cleaning, while roughness plays at most a small role. Aggressive surface treatment is shown to damage the crystalline substrate and degrade resonator quality. We also introduce methods to characterize and remove ultra-thin resist residue, providing a way to quantify and minimize remnant sources of loss on device surfaces. [ABSTRACT FROM AUTHOR]

The Lys requirement of nursery pigs may be dependent on the source of nonessential AA (NEAA) nitrogen or the source of Lys itself. However, little peer-reviewed data examines these phenomena. The objectives of these experiments were to determine if the Lys requirement of pigs is altered when 1 ) low protein diets are supplemented with different sources of NEAA nitrogen or 2) Lys is supplied as a crystalline source instead of intact protein such as soybean meal (SBM). Two 14-d experiments were conducted using 450 (Exp. 1) and 540 (Exp. 2) pigs (PIC C22/C29 x 337). There were 10 treatments in each experiment, each aligned as a 2 x 5 factorial. In Exp. 1, there were 2 sources of NEAA (L-Gln + L-Gly or L-Gly + L-Ala + L-Pro + L-His) and 5 levels of Lys (1.2, 1.3, 1.4, 1.5, and 1.6%). In Exp. 2, there were 2 sources of proteins providing additional Lys (L-Lys HC1 or SBM) and the same 5 levels of Lys. Following weaning at 18 to 22 d of age, pigs were fed a common starter diet for 5 d postweaning followed by a 14-d treatment period. Pigs were weighed and feed disappearance determined on d 0, 7, and 14 of the experiment. Data were analyzed using the MIXED and NLIN procedures of SAS (SAS Inst., Cary, NC). In Exp. 1, increasing CP and Lys resulted in a quadratic increase (P < 0.05) in ADG and a linear improvement (P < 0.05) in G:F during the 14-d treatment period. Breakpoint regression analyses revealed that optimum ADG was obtained at 1.36% Lys, while optimum G:F was obtained at 1.45% Lys. The source of NEAA did not affect (P > 0.10) growth performance during the treatment period. In Exp. 2, both ADG and G:F increased linearly (P < 0.05) with increasing Lys. Optimal ADG was obtained at 1.47% Lys, but the breakpoint for optimum G:F was above tested levels. Source of Lys did not affect (P > 0.10) ADG, but pigs fed additional Lys from crystalline sources had improved (P < 0.05) G:F than those fed additional Lys from intact protein at 1.50% Lys; however, the analyzed Lys values at this level differ. Overall, these data show that the standardized ileal digestibility Lys requirement of pigs is not altered when low protein diets are supplemented with different sources of NEAA nitrogen. Feed efficiency appears to be maximized when additional Lys is supplied by L-Lys HC1 instead of SBM, but more research is needed to confirm this phenomenon. [ABSTRACT FROM AUTHOR]

We present a lumped-element Josephson parametric amplifier designed to operate with strong coupling to the environment. In this regime, we observe broadband frequency dependent amplification with multi-peaked gain profiles. We account for this behavior using the "pumpistor" model which allows for frequency dependent variation of the external impedance. Using this understanding, we demonstrate control over the complexity of gain profiles through added variation in the environment impedance at a given frequency. With strong coupling to a suitable external impedance, we observe a significant increase in dynamic range, and large amplification bandwidth up to 700 MHz giving near quantum-limited performance. [ABSTRACT FROM AUTHOR]

We present a method for optimizing quantum control in experimental systems, using a subset of randomized benchmarking measurements to rapidly infer error. This is demonstrated to improve singleand two-qubit gates, minimize gate bleedthrough, where a gate mechanism can cause errors on subsequent gates, and identify control crosstalk in superconducting qubits. This method is able to correct parameters so that control errors no longer dominate and is suitable for automated and closed-loop optimization of experimental systems. [ABSTRACT FROM AUTHOR]