Magic-State Functional Units: Mapping and Scheduling Multi-Level Distillation Circuits for Fault-Tolerant Quantum Architectures

Quantum computers have recently made great strides and are on a long-term path towards useful fault-tolerant computation. A dominant overhead in fault-tolerant quantum computation is the production of high-fidelity encoded qubits, called magic states, which enable reliable error-corrected computation. We present the first detailed designs of hardware functional units that implement space-time optimized magic-state factories for surface code error-corrected machines. Interactions among distant qubits require surface code braids (physical pathways on chip) which must be routed. Magic-state factories are circuits comprised of a complex set of braids that is more difficult to route than quantum circuits considered in previous work [1]. This paper explores the impact of scheduling techniques, such as gate reordering and qubit renaming, and we propose two novel mapping techniques: braid repulsion and dipole moment braid rotation. We combine these techniques with graph partitioning and community detection algorithms, and further introduce a stitching algorithm for mapping subgraphs onto a physical machine. Our results show a factor of 5.64 reduction in space-time volume compared to the best-known previous designs for magic-state factories.Comment: 13 pages, 10 figure

Resource Optimized Quantum Architectures for Surface Code Implementations of Magic-State Distillation

Quantum computers capable of solving classically intractable problems are under construction, and intermediate-scale devices are approaching completion. Current efforts to design large-scale devices require allocating immense resources to error correction, with the majority dedicated to the production of high-fidelity ancillary states known as magic-states. Leading techniques focus on dedicating a large, contiguous region of the processor as a single "magic-state distillation factory" responsible for meeting the magic-state demands of applications. In this work we design and analyze a set of optimized factory architectural layouts that divide a single factory into spatially distributed factories located throughout the processor. We find that distributed factory architectures minimize the space-time volume overhead imposed by distillation. Additionally, we find that the number of distributed components in each optimal configuration is sensitive to application characteristics and underlying physical device error rates. More specifically, we find that the rate at which T-gates are demanded by an application has a significant impact on the optimal distillation architecture. We develop an optimization procedure that discovers the optimal number of factory distillation rounds and number of output magic states per factory, as well as an overall system architecture that interacts with the factories. This yields between a 10x and 20x resource reduction compared to commonly accepted single factory designs. Performance is analyzed across representative application classes such as quantum simulation and quantum chemistry.Comment: 16 pages, 14 figure

HoxA3 is an apical regulator of haemogenic endothelium.

During development, haemogenesis occurs invariably at sites of vasculogenesis. Between embryonic day (E) 9.5 and E10.5 in mice, endothelial cells in the caudal part of the dorsal aorta generate haematopoietic stem cells and are referred to as haemogenic endothelium. The mechanisms by which haematopoiesis is restricted to this domain, and how the morphological transformation from endothelial to haematopoietic is controlled are unknown. We show here that HoxA3, a gene uniquely expressed in the embryonic but not yolk sac vasculature, restrains haematopoietic differentiation of the earliest endothelial progenitors, and induces reversion of the earliest haematopoietic progenitors into CD41-negative endothelial cells. This reversible modulation of endothelial-haematopoietic state is accomplished by targeting key haematopoietic transcription factors for downregulation, including Runx1, Gata1, Gfi1B, Ikaros, and PU.1. Through loss-of-function, and gain-of-function epistasis experiments, and the identification of antipodally regulated targets, we show that among these factors, Runx1 is uniquely able to erase the endothelial program set up by HoxA3. These results suggest both why a frank endothelium does not precede haematopoiesis in the yolk sac, and why haematopoietic stem cell generation requires Runx1 expression only in endothelial cells

SPROUTING ANGIOGENESIS DURING RETINAL DEVELOPMENT AND WOUND HEALING

Endothelial cells, the cells that line blood vessels, become activated during development to sprout and form new vessels in a process termed angiogenesis. During development, sprouting angiogenesis is robust and is the main driving force behind vascularization of new tissues in the embryo. In contrast, endothelial cells are mainly quiescent in the adult and only become reactivated during physiological or pathological angiogenesis. The bone morphogenetic protein (BMP) pathway has been shown to be a pro-angiogenic cue. During postnatal retinal development, BMP receptors are expressed in the retinal vasculature and BMP ligands are expressed throughout the retina. Here, we show that deletion of BMP receptors, Alk1, Alk2, Alk3, and BMPR2 affect sprouting angiogenesis during development. Endothelial specific deletion of Alk2, Alk3, and BMPR2 resulted in decreased sprouting at the vascular front as well as branching in the vascular plexus, whereas deletion of Alk1 resulted in increased sprouting. These data point to a requirement of BMP signaling for proper patterning of the retinal vasculature during development. We also analyzed tortuous microvessels, abnormal vessels that arise during the wound healing process. Tortuous vessels are observed in many diseases, most notably cancer and diabetes. However, the causes and consequences of these abnormal vessels have not been elucidated. Here, we use intravital, high-resolution imaging to examine the formation, resolution, and sprouting of tortuous microvessels during wound healing. We found that tortuous microvessels are mainly located 100-300 μm from the wound center and that tortuous microvessels resolved by becoming normal again. Additionally, using fluorescent, microcarrier beads we found that beads became stuck in tortuous microvessels suggesting differences in flow. The shapes of endothelial cells within tortuous microvessels are round, indicative of activated cells, and exhibit sprout initiations at a higher frequency than normal vessels. Thus, we highlight an important, undiscovered feature of tortuous microvessels, sprouting, that can be used as a therapeutic target to normalize tortuous vessels during disease.Doctor of Philosoph

Optimized Surface Code Communication in Superconducting Quantum Computers

Quantum computing (QC) is at the cusp of a revolution. Machines with 100 quantum bits (qubits) are anticipated to be operational by 2020 [googlemachine,gambetta2015building], and several-hundred-qubit machines are around the corner. Machines of this scale have the capacity to demonstrate quantum supremacy, the tipping point where QC is faster than the fastest classical alternative for a particular problem. Because error correction techniques will be central to QC and will be the most expensive component of quantum computation, choosing the lowest-overhead error correction scheme is critical to overall QC success. This paper evaluates two established quantum error correction codes---planar and double-defect surface codes---using a set of compilation, scheduling and network simulation tools. In considering scalable methods for optimizing both codes, we do so in the context of a full microarchitectural and compiler analysis. Contrary to previous predictions, we find that the simpler planar codes are sometimes more favorable for implementation on superconducting quantum computers, especially under conditions of high communication congestion.Comment: 14 pages, 9 figures, The 50th Annual IEEE/ACM International Symposium on Microarchitectur

Characterization of Electronic Cigarette Aerosol and Its Induction of Oxidative Stress Response in Oral Keratinocytes.

In this study, we have generated and characterized Electronic Cigarette (EC) aerosols using a combination of advanced technologies. In the gas phase, the particle number concentration (PNC) of EC aerosols was found to be positively correlated with puff duration whereas the PNC and size distribution may vary with different flavors and nicotine strength. In the liquid phase (water or cell culture media), the size of EC nanoparticles appeared to be significantly larger than those in the gas phase, which might be due to aggregation of nanoparticles in the liquid phase. By using in vitro high-throughput cytotoxicity assays, we have demonstrated that EC aerosols significantly decrease intracellular levels of glutathione in NHOKs in a dose-dependent fashion resulting in cytotoxicity. These findings suggest that EC aerosols cause cytotoxicity to oral epithelial cells in vitro, and the underlying molecular mechanisms may be or at least partially due to oxidative stress induced by toxic substances (e.g., nanoparticles and chemicals) present in EC aerosols

Microbiota Presente En Las Superficies De Contacto De Las Unidades Dentales De La Clínica Estomatológica De La Universidad Cesar Vallejo, Piura 2017

La presente investigación fue de tipo descriptivo y de corte transversal, cuyo objetivo principal fue determinar la microbiota presente en las superficies de contacto de las unidades dentales de la Clínica Estomatológica de la Universidad Cesar Vallejo, Piura 2017. Se evaluaron 54 unidades dentales de esta Clínica y se tomó como muestra las superficies de mayor contacto, las cuales fueron bandeja, escupidera, brazo, aspiradora y lámpara. La técnica que se usó para el muestreo de esta investigación fue la técnica microbiológica del hisopado. Se prepararon medios de cultivos selectivos y diferenciales para obtener los aislamientos y los recuentos. Los resultados indican que la escupidera fue la superficie que presentó la frecuencia más elevada alcanzando un recuento total de 73440 UFC de microorganismos Mesófilos aerobios considerados microorganismos indicadores de contaminación. Se concluye que el manejo de la higienización en la Clínica Estomatológica de la universidad Cesar Vallejo es deficiente por parte del operador como del personal de limpieza

Microbiota Presente En Las Superficies De Contacto De Las Unidades Dentales De La Clínica Estomatológica De La Universidad Cesar Vallejo, Piura 2017

La presente investigación fue de tipo descriptivo y de corte transversal, cuyo objetivo principal fue determinar la microbiota presente en las superficies de contacto de las unidades dentales de la Clínica Estomatológica de la Universidad Cesar Vallejo, Piura 2017. Se evaluaron 54 unidades dentales de esta Clínica y se tomó como muestra las superficies de mayor contacto, las cuales fueron bandeja, escupidera, brazo, aspiradora y lámpara. La técnica que se usó para el muestreo de esta investigación fue la técnica microbiológica del hisopado. Se prepararon medios de cultivos selectivos y diferenciales para obtener los aislamientos y los recuentos. Los resultados indican que la escupidera fue la superficie que presentó la frecuencia más elevada alcanzando un recuento total de 73440 UFC de microorganismos Mesófilos aerobios considerados microorganismos indicadores de contaminación. Se concluye que el manejo de la higienización en la Clínica Estomatológica de la universidad Cesar Vallejo es deficiente por parte del operador como del personal de limpieza

Tile size selection for low-power tile-based architectures

In this paper, we investigate the power implications of tile size selection for tile-based processors. We refer to this investigation as a tile granularity study. This is accomplished by distilling the architectural cost of tiles with different computational widths into a system metric we call the Granularity Indicator (GI). The GI is then compared against the communications exposed when algorithms are partitioned across multiple tiles. Through this comparison, the tile granularity that best fits a given set of algorithms can be determined, reducing the system power for that set of algorithms. When the GI analysis is applied to the Synchroscalar tile architecture[1], we find that Synchroscalar\u27s already low power consumption can be further reduced by 14% when customized for execution of the 802.11a receiver. In addition, the GI can also be a used to evaluate tile size when considering multiple applications simultaneously, providing a convenient platform for hardware-software co-design

Event and model dependent rainfall adjustments to improve discharge predictions

Most conceptual rainfall–runoff models use as input spatially averaged rainfall fields which are typically associated with significant errors that affect the model outcome. In this study, it is hypothesized that a simple spatially and temporally averaged event–dependent rainfall multiplier can account for errors in the rainfall input. The potentials and limitations of this lumped multiplier approach are explored by evaluating the effects of multipliers on the accuracy and precision of the predictive distributions. Parameter sets found to be behavioural across a range of different flood events were assumed to be a good representation of the catchment dynamics and were used to identify rainfall multipliers for each of the individual events. An effect of the parameter sets on identified multipliers was found, however it was small compared to the differences between events. Accounting for event–dependent multipliers improved the reliability of the predictions. At the cost of a small decrease in precision, the distribution of identified multipliers for past events can be used to account for possible rainfall errors when predicting future events. By using behavioural parameter sets to identify rainfall multipliers, the method offers a simple and computationally efficient way to address rainfall errors in hydrological modelling