An efficient behavioral screening platform classifies natural products and other chemical cues according to their chemosensory valence in C. elegans.

Throughout history, humans have relied on plants as a source of medication, flavoring, and food. Plants synthesize large chemical libraries and release many of these compounds into the rhizosphere and atmosphere where they affect animal and microbe behavior. To survive, nematodes must have evolved the sensory capacity to distinguish plant-made small molecules (SMs) that are harmful and must be avoided from those that are beneficial and should be sought. This ability to classify chemical cues as a function of their value is fundamental to olfaction, and represents a capacity shared by many animals, including humans. Here, we present an efficient platform based on multi-well plates, liquid handling instrumentation, inexpensive optical scanners, and bespoke software that can efficiently determine the valence (attraction or repulsion) of single SMs in the model nematode, Caenorhabditis elegans. Using this integrated hardware-wetware-software platform, we screened 90 plant SMs and identified 37 that attracted or repelled wild-type animals, but had no effect on mutants defective in chemosensory transduction. Genetic dissection indicates that for at least 10 of these SMs, response valence emerges from the integration of opposing signals, arguing that olfactory valence is often determined by integrating chemosensory signals over multiple lines of information. This study establishes that C. elegans is an effective discovery engine for determining chemotaxis valence and for identifying natural products detected by the chemosensory nervous system.

A machine learning approach to personalized predictors of dyslipidemia: a cohort study.

Introduction: Mexico ranks second in the global prevalence of obesity in the adult population, which increases the probability of developing dyslipidemia. Dyslipidemia is closely related to cardiovascular diseases, which are the leading cause of death in the country. Therefore, developing tools that facilitate the prediction of dyslipidemias is essential for prevention and early treatment. Methods: In this study, we utilized a dataset from a Mexico City cohort consisting of 2,621 participants, men and women aged between 20 and 50 years, with and without some type of dyslipidemia. Our primary objective was to identify potential factors associated with different types of dyslipidemia in both men and women. Machine learning algorithms were employed to achieve this goal. To facilitate feature selection, we applied the Variable Importance Measures (VIM) of Random Forest (RF), XGBoost, and Gradient Boosting Machine (GBM). Additionally, to address class imbalance, we employed Synthetic Minority Over-sampling Technique (SMOTE) for dataset resampling. The dataset encompassed anthropometric measurements, biochemical tests, dietary intake, family health history, and other health parameters, including smoking habits, alcohol consumption, quality of sleep, and physical activity. Results: Our results revealed that the VIM algorithm of RF yielded the most optimal subset of attributes, closely followed by GBM, achieving a balanced accuracy of up to 80%. The selection of the best subset of attributes was based on the comparative performance of classifiers, evaluated through balanced accuracy, sensitivity, and specificity metrics. Discussion: The top five features contributing to an increased risk of various types of dyslipidemia were identified through the machine learning technique. These features include body mass index, elevated uric acid levels, age, sleep disorders, and anxiety. The findings of this study shed light on significant factors that play a role in dyslipidemia development, aiding in the early identification, prevention, and treatment of this condition.

[Social, demographic and morbimortality characteristics of the cases treated for COVID-19 at the Ignacio Chávez National Institute of Cardiology. A descriptive cross-sectional study]. / Características sociales, demográficas y de morbimortalidad de los casos atendidos por COVID-19 en el Instituto Nacional de Cardiología Ignacio Chávez. Un estudio transversal descriptivo.

Introduction: The COVID-19 pandemic brought with it a large number of adverse consequences for public health with serious socioeconomic repercussions. In this study we characterize the social, demographic, morbidity and mortality conditions of individuals treated for COVID-19 in one of the SARS-CoV-2 reference hospitals in Mexico City. Method: A descriptive cross-sectional study was carried out in 259 patients discharged from the Instituto Nacional de Cardiología Ignacio Chávez, between April 11, 2020 and March 14, 2021. A multivariate logistic regression model was used to identify the association between sociodemographic and clinical variables. An optimization was performed using maximum likelihood calculations to choose the best model compatible with the data. The maximum likelihood model was evaluated using ROC curves, goodnessof-fit estimators, and multicollinearity analysis. Statistically significant patterns of comorbidities were inferred by evaluating a hypergeometric test over the frequencies of co-occurrence of pairs of conditions. A network analysis was implemented to determine connectivity patterns based on degree centrality, between comorbidities and outcome variables. Results: The main social disadvantages of the studied population are related to the lack of social security (96.5%) and the lag in housing conditions (81%). Variables associated with the probability of survival were being younger (p < 0.0001), having more durable material goods (p = 0.0034) and avoiding: pneumonia (p = 0.0072), septic shock (p < 0.0001) and acute respiratory failure (p < 0.0001); (AUROC: 91.5%). The comorbidity network for survival cases has a high degree of connectivity between conditions such as cardiac arrhythmias and essential arterial hypertension (Degree Centrality = 90 and 78, respectively). Conclusions: Given that among the factors associated with survival to COVID-19 there are clinical, sociodemographic and social determinants of health variables, in addition to age; It is imperative to consider the various factors that may affect or modify the health status of a population, especially when addressing emerging epidemic phenomena such as the current COVID-19 pandemic.

Introducción: La pandemia de enfermedad por coronavirus 2019 (COVID-19) trajo aparejadas una gran cantidad de consecuencias adversas para la salud pública con serias repercusiones socioeconómicas. En este estudio caracterizamos las condiciones sociales, demográficas y de morbimortalidad de los casos atendidos por COVID-19 en uno de los hospitales de referencia de coronavirus 2 del síndrome respiratorio agudo grave (SARS-CoV-2) en la Ciudad de México. Método: Se llevó a cabo un estudio transversal descriptivo en 259 pacientes egresados del Instituto Nacional de Cardiología Ignacio Chávez, entre el 11 de abril de 2020 y el 14 de marzo de 2021. Se utilizó un modelo de regresión logística multivariante para identificar la asociación entre variables sociodemográficas y clínicas. Se realizó una optimización mediante cálculos de máxima verosimilitud para elegir el mejor modelo compatible con los datos. El modelo de máxima verosimilitud fue evaluado mediante curvas ROC, estimadores de bondad de ajuste y análisis de multicolinealidad. Se infirieron patrones de comorbilidades estadísticamente significativos mediante la evaluación de una prueba hipergeométrica en las frecuencias de coocurrencia de pares de condiciones. Se implementó un análisis de redes para determinar los patrones de conectividad basado en la centralidad de grado, entre algunas comorbilidades y las variables de desenlace. Resultados: Las principales desventajas sociales de la población estudiada se relacionan con la falta de seguridad social (96.5%) y el rezago en las condiciones de vivienda (81%). Las variables asociadas a la probabilidad de sobrevivir fueron tener una menor edad (p < 0.0001), contar con más bienes materiales durables (p = 0.0034) y evitar: la neumonía (p = 0.0072), el choque séptico (p < 0.0001) y la insuficiencia respiratoria aguda (p < 0.0001); (AUROC: 91.5%). Las red de comorbilidades para los casos de supervivencia tienen un alto grado de conectividad entre padecimientos como las arritmias cardiacas e hipertensión arterial esencial (centralidad de grado: 90 y 78 respectivamente). Conclusiones: En vista de que entre los factores asociados a supervivencia existen variables clínicas, sociodemográficas y determinantes sociales de la salud, además de la edad, resulta imperativo considerar los diversos factores que puedan incidir o modificar el estado de salud de una población, sobre todo al abordar los fenómenos epidémicos emergentes como es el caso de la actual pandemia de COVID-19.

Demonstrating a Continuous Set of Two-Qubit Gates for Near-Term Quantum Algorithms.

Quantum algorithms offer a dramatic speedup for computational problems in material science and chemistry. However, any near-term realizations of these algorithms will need to be optimized to fit within the finite resources offered by existing noisy hardware. Here, taking advantage of the adjustable coupling of gmon qubits, we demonstrate a continuous two-qubit gate set that can provide a threefold reduction in circuit depth as compared to a standard decomposition. We implement two gate families: an imaginary swap-like (iSWAP-like) gate to attain an arbitrary swap angle, θ, and a controlled-phase gate that generates an arbitrary conditional phase, ϕ. Using one of each of these gates, we can perform an arbitrary two-qubit gate within the excitation-preserving subspace allowing for a complete implementation of the so-called Fermionic simulation (fSim) gate set. We benchmark the fidelity of the iSWAP-like and controlled-phase gate families as well as 525 other fSim gates spread evenly across the entire fSim(θ,ϕ) parameter space, achieving a purity-limited average two-qubit Pauli error of 3.8×10^{-3} per fSim gate.

Diabatic Gates for Frequency-Tunable Superconducting Qubits.

We demonstrate diabatic two-qubit gates with Pauli error rates down to 4.3(2)×10^{-3} in as fast as 18 ns using frequency-tunable superconducting qubits. This is achieved by synchronizing the entangling parameters with minima in the leakage channel. The synchronization shows a landscape in gate parameter space that agrees with model predictions and facilitates robust tune-up. We test both iswap-like and cphase gates with cross-entropy benchmarking. The presented approach can be extended to multibody operations as well.

Luxación expuesta de la primera y segunda cuña y fractura in situ de la tercera cuña del pie: caso clínico y revisión de la literatura / Exposed dislocation of the first and second cuneiform bones and fracture in situ of the third cuneiform bone of the foot: Clinical case and literature review

Resumen: Antecedentes: La fractura y la luxación aislada de los huesos cuneiformes son un evento no muy frecuente y sólo pocos casos han sido reportados en la literatura. Este tipo de eventos se presenta como una variación de las lesiones de Lisfranc. El presente reporte muestra un caso clínico poco frecuente de un paciente con luxación de la primera y segunda cuña y fractura in situ de la tercera cuña del pie izquierdo. Caso clínico: Mujer de 49 años de edad, que presentó traumatismo severo del dorso del pie con exposición de tejido óseo y blando como consecuencia de atropellamiento. La paciente fue sometida a cirugía en el Servicio de Urgencias, donde se realizó aseo quirúrgico, desbridamiento, reducción de la luxación de la primera y segunda cuña y fijación percutánea con clavillos Kirschner de 2.0 mm. Resultados: Posterior a la cirugía, la paciente se reportó con buen estado en general, orientada, sin facie de dolor, estable, consciente, sin huellas de sangrado activo por la herida y con presencia de clavillos Kirschner en adecuada posición. Discusión: Se recomienda una inspección exhaustiva de la lesión a través del análisis de las imágenes de rayos X, tomografía computarizada o imágenes de resonancia magnética, especialmente en lesiones no expuestas, pues con ello se puede aplicar el tratamiento adecuado y lograr una pronta recuperación del paciente.

Abstract: Backgrounds: The isolated fracture/dislocation of the cuneiform bones is a not very frequent event and only a few cases have been reported in the literature. This type of event is presented as a variation of the Lisfranc injuries. The present report shows a rare clinical case of a patient with dislocation of the first and second cuneiform bones and fracture in situ of the third cuneiform bone of the left foot. Case report: A 49-year-old female patient presented severe traumatism of the dorsum of the foot with bony and soft tissue exposure as a result of a car accident. The patient underwent surgery in the emergency department consisting of surgical cleaning, debridement, reduction of dislocation of the first and second cuneiform bones and percutaneous fixation with 2.0 mm Kirschner wires. Results: After the surgery, the patient was found to be in good general condition, oriented without pain, stable, conscious, without traces of active bleeding from the wound and with the presence of Kirschner wires in an appropriate position. Discussion: An exhaustive inspection of the injury is recommended through the analysis of X-ray images, CT scans or magnetic resonance imaging, especially in unexposed lesions in order to apply the appropriate treatment and be able to achieve a prompt recovery of the patient.

Prp8 impacts cryptic but not alternative splicing frequency.

Pre-mRNA splicing must occur with extremely high fidelity. Spliceosomes assemble onto pre-mRNA guided by specific sequences (5' splice site, 3' splice site, and branchpoint). When splice sites are mutated, as in many hereditary diseases, the spliceosome can aberrantly select nearby pseudo- or "cryptic" splice sites, often resulting in nonfunctional protein. How the spliceosome distinguishes authentic splice sites from cryptic splice sites is poorly understood. We performed a Caenorhabditis elegans genetic screen to find cellular factors that affect the frequency with which the spliceosome uses cryptic splice sites and identified two alleles in core spliceosome component Prp8 that alter cryptic splicing frequency. Subsequent complementary genetic and structural analyses in yeast implicate these alleles in the stability of the spliceosome's catalytic core. However, despite a clear effect on cryptic splicing, high-throughput mRNA sequencing of these prp-8 mutant C. elegans reveals that overall alternative splicing patterns are relatively unchanged. Our data suggest the spliceosome evolved intrinsic mechanisms to reduce the occurrence of cryptic splicing and that these mechanisms are distinct from those that impact alternative splicing.

[Exposed dislocation of the first and second cuneiform bones and fracture in situ of the third cuneiform bone of the foot: Clinical case and literature review]. / Luxación expuesta de la primera y segunda cuña y fractura in situ de la tercera cuña del pie: Caso clínico y revisión de la literatura.

BACKGROUNDS: The isolated fracture/dislocation of the cuneiform bones is a not very frequent event and only a few cases have been reported in the literature. This type of event is presented as a variation of the Lisfranc injuries. The present report shows a rare clinical case of a patient with dislocation of the first and second cuneiform bones and fracture in situ of the third cuneiform bone of the left foot. CASE REPORT: A 49-year-old female patient presented severe traumatism of the dorsum of the foot with bony and soft tissue exposure as a result of a car accident. The patient underwent surgery in the emergency department consisting of surgical cleaning, debridement, reduction of dislocation of the first and second cuneiform bones and percutaneous fixation with 2.0 mm Kirschner wires. RESULTS: After the surgery, the patient was found to be in good general condition, oriented without pain, stable, conscious, without traces of active bleeding from the wound and with the presence of Kirschner wires in an appropriate position. DISCUSSION: An exhaustive inspection of the injury is recommended through the analysis of X-ray images, CT scans or magnetic resonance imaging, especially in unexposed lesions in order to apply the appropriate treatment and be able to achieve a prompt recovery of the patient.

ANTECEDENTES: La fractura y la luxación aislada de los huesos cuneiformes son un evento no muy frecuente y sólo pocos casos han sido reportados en la literatura. Este tipo de eventos se presenta como una variación de las lesiones de Lisfranc. El presente reporte muestra un caso clínico poco frecuente de un paciente con luxación de la primera y segunda cuña y fractura in situ de la tercera cuña del pie izquierdo. CASO CLÍNICO: Mujer de 49 años de edad, que presentó traumatismo severo del dorso del pie con exposición de tejido óseo y blando como consecuencia de atropellamiento. La paciente fue sometida a cirugía en el Servicio de Urgencias, donde se realizó aseo quirúrgico, desbridamiento, reducción de la luxación de la primera y segunda cuña y fijación percutánea con clavillos Kirschner de 2.0 mm. RESULTADOS: Posterior a la cirugía, la paciente se reportó con buen estado en general, orientada, sin facie de dolor, estable, consciente, sin huellas de sangrado activo por la herida y con presencia de clavillos Kirschner en adecuada posición. DISCUSIÓN: Se recomienda una inspección exhaustiva de la lesión a través del análisis de las imágenes de rayos X, tomografía computarizada o imágenes de resonancia magnética, especialmente en lesiones no expuestas, pues con ello se puede aplicar el tratamiento adecuado y lograr una pronta recuperación del paciente.

SNRP-27, the C. elegans homolog of the tri-snRNP 27K protein, has a role in 5' splice site positioning in the spliceosome.

The tri-snRNP 27K protein is a component of the human U4/U6-U5 tri-snRNP and contains an N-terminal phosphorylated RS domain. In a forward genetic screen in C. elegans, we previously identified a dominant mutation, M141T, in the highly-conserved C-terminal region of this protein. The mutant allele promotes changes in cryptic 5' splice site choice. To better understand the function of this poorly characterized splicing factor, we performed high-throughput mRNA sequencing analysis on worms containing this dominant mutation. Comparison of alternative splice site usage between the mutant and wild-type strains led to the identification of 26 native genes whose splicing changes in the presence of the snrp-27 mutation. The changes in splicing are specific to alternative 5' splice sites. Analysis of new alleles suggests that snrp-27 is an essential gene for worm viability. We performed a novel directed-mutation experiment in which we used the CRISPR-cas9 system to randomly generate mutations specifically at M141 of SNRP-27. We identified eight amino acid substitutions at this position that are viable, and three that are homozygous lethal. All viable substitutions at M141 led to varying degrees of changes in alternative 5' splicing of native targets. We hypothesize a role for this SR-related factor in maintaining the position of the 5' splice site as U1snRNA trades interactions at the 5' end of the intron with U6snRNA and PRP8 as the catalytic site is assembled.

A blueprint for demonstrating quantum supremacy with superconducting qubits.

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.

Procesos de acreditación de la formación de posgrado en carreras de salud en argentina: hacia la consolidación de un sistema articulado / Accreditation processes of postgraduate training in health careers in Argentina: towards the consolidation of an articulated system

INTRODUCCIÓN El título de grado de médico es habilitante para el ejercicio de la profesión. No obstante, los médicos egresados eligen continuar su formación de posgrado, que incluye especialidades, maestrías y doctorados (en el ámbito educativo) y residencias (en el ámbito de salud). Existen carreras de especialista universitario asociadas a residencias. Algunas deben pasar por un doble proceso de evaluación por parte de la Comisión Nacional de Evaluación y Acreditación Universitaria (CONEAU) y del Sistema Nacional de Acreditación de Residencias del Equipo de Salud (SNARES). Estas situaciones evidencian la necesidad de consolidar un sistema integrado de acreditación para la formación de médicos especialistas, que se oriente a alcanzar similares estándares de calidad. OBJETIVOS Establecer los procesos necesarios para construir un sistema de acreditación conjunta de las carreras de posgrado de especialista en el campo de la salud, que funcionan en asociación con una residencia del Sistema Nacional de Residencias del Equipo de Salud. MÉTODOS La presente investigación se planteó como un estudio de implementación, de diseño cualitativo, en el que se utilizaron varias técnicas de recolección de datos. Se analizaron las normativas y los procesos de acreditación llevados adelante tanto por el SNARES (sobre las residencias) como por la CONEAU. El análisis empírico de casos sujetos a un doble proceso de acreditación, por estar asociada una carrera a una residencia, se realizó sobre una muestra definida en relación con los hallazgos de la primera etapa del estudio. RESULTADOS La cantidad de carreras de especialización universitaria asociadas a residencias es aún marginal en relación con la cantidad de sedes a nivel nacional. Discusión pensar en un sistema de acreditación integrado requiere revisar los procesos de definición de una política de formación de especialistas, que garantice criterios de equidad y de calidad. Es fundamental consolidar políticas a nivel de Estado, unificar los procedimientos y consensuar estándares.

Spectroscopic signatures of localization with interacting photons in superconducting qubits.

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.

Observation of Classical-Quantum Crossover of 1/f Flux Noise and Its Paramagnetic Temperature Dependence.

By analyzing the dissipative dynamics of a tunable gap flux qubit, we extract both sides of its two-sided environmental flux noise spectral density over a range of frequencies around 2k_{B}T/h≈1 GHz, allowing for the observation of a classical-quantum crossover. Below the crossover point, the symmetric noise component follows a 1/f power law that matches the magnitude of the 1/f noise near 1 Hz. The antisymmetric component displays a 1/T dependence below 100 mK, providing dynamical evidence for a paramagnetic environment. Extrapolating the two-sided spectrum predicts the linewidth and reorganization energy of incoherent resonant tunneling between flux qubit wells.

Measurement-Induced State Transitions in a Superconducting Qubit: Beyond the Rotating Wave Approximation.

Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the qubit if the number of photons in the resonator is too high. We investigate these transitions and find that they can push the qubit out of the two-level subspace, and that they show resonant behavior as a function of photon number. We develop a theory for these observations based on level crossings within the Jaynes-Cummings ladder, with transitions mediated by terms in the Hamiltonian that are typically ignored by the rotating wave approximation. We find that the most important of these terms comes from an unexpected broken symmetry in the qubit potential. We confirm the theory by measuring the photon occupation of the resonator when transitions occur while varying the detuning between the qubit and resonator.

Validation of an Argentine version of Lupus Quality of Life questionnaire.

OBJECTIVE: To determine reproducibility and validity of an Argentine version of the Lupus Quality of Life questionnaire (LupusQoL) and to determine cut-off values in the questionnaire. MATERIALS AND METHODS: One hundred and forty-seven systemic lupus erythematosus patients (American College of Rheumatology 1982/1997) were assessed from April 2014 to July 2014. Demographic and socioeconomic variables were collected, as well as SELENA/SLEDAI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index Score, comorbidities and treatment data. Patients completed LupusQoL-Argentine version and European Quality of Life Questionnaire (EuroQoL-5D). Internal consistency and reliability were examined. Convergent validity with EuroQoL-5D was assessed through analysis of latent classes, which established homogeneous categories from the responses of each domain of LupusQoL and for the total. RESULTS: Out of 147 patients, 93.2% were female, mean age 36.4 ± 11.1 years, mean disease duration 2.7 ± 9 years, mean SELENA/SLEDAI 2.7 ± 3 points. The cut-off point that defined good or bad quality of life was 0.739 for EuroQoL 5D and 63 for LupusQoL. Cut-off values for each LupusQoL domain were also defined, creating two classes in each of them. There was moderate to high concordance to classify quality of life (Kappa = 0.74, 95% confidence interval = 0.54, 0.95). CONCLUSION: The Argentine version of LupusQoL is a valid, reliable and reproducible instrument to assess quality of life. In this study, cut-off points that allow the classification of patients regarding whether they have good or bad quality of life are established for the first time.

Digitized adiabatic quantum computing with a superconducting circuit.

Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

Measuring and Suppressing Quantum State Leakage in a Superconducting Qubit.

Leakage errors occur when a quantum system leaves the two-level qubit subspace. Reducing these errors is critically important for quantum error correction to be viable. To quantify leakage errors, we use randomized benchmarking in conjunction with measurement of the leakage population. We characterize single qubit gates in a superconducting qubit, and by refining our use of derivative reduction by adiabatic gate pulse shaping along with detuning of the pulses, we obtain gate errors consistently below 10^{-3} and leakage rates at the 10^{-5} level. With the control optimized, we find that a significant portion of the remaining leakage is due to incoherent heating of the qubit.

Flux noise probed with real time qubit tomography in a Josephson phase qubit.

We measure the dependence of qubit phase coherence and flux noise on inductor loop geometry. While wider inductor traces change neither the flux noise power spectrum nor the qubit dephasing time, increased inductance leads to a simultaneous increase in both. Using our new tomographic protocol for measuring low frequency flux noise, we make a direct comparison between the flux noise spectrum and qubit phase decay, finding agreement within 10% of theory.

Fast tunable coupler for superconducting qubits.

A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. The coupler has a measured on/off ratio of 1000. The design is self-contained and physically separate from the qubits, allowing the coupler to be used as a module to connect a variety of elements such as qubits, resonators, amplifiers, and readout circuitry over distances much larger than nearest-neighbor. Such design flexibility is likely to be useful for a scalable quantum computer.