Decoherence-protected quantum register of nuclear spins in diamond

Solid-state quantum registers are exceptional for storing quantum information at room temperature with long coherence time. Nevertheless, practical applications toward quantum supremacy require even longer coherence time to allow for more complex algorithms. In this work we propose a quantum register that lies in a decoherence-protected subspace to be implemented with nuclear spins nearby a Nitrogen-Vacancy center in diamond. The quantum information is encoded in two logical states composed of two Carbon-13 nuclear spins, while an electron spin is used as ancilla for initialization and control. Moreover, by tuning an off-axis magnetic field we enable non-nuclear-spin- preserving transitions that we use for preparing and manipulating the register through Stimulating Raman Adiabatic Passage. Furthermore, we consider more elaborated sequences to improve simultaneous control over the system yielding decreased gate time.

Social Interaction and Social Media At Airport Departure Gates

An observational study was conducted at airline departure gates in several U.S. and European countries. Thirty-second observations were randomly made of 1360 different individuals ranging in age from infants to the elderly, although 79% of the travelers were adults. Most of the individuals were traveling with someone, except for adults who were more often traveling alone (58% vs. 42% time). Of the different types of social interaction and social media observed, cell phone texting/scrolling was significantly more frequently observed (at 53% time) than cell phone talking (13 % time), face-to-face interaction (13% time), on computer (7%) and touching (4%) which was the least frequently observed behavior. Significantly more cell phone texting/scrolling time occurred when adults were traveling alone (58% time). These data suggest that airline travelers are spending significantly more airport departure gate time on social media (specifically cell phone texting/scrolling) than face-to-face interaction or touching. Unfortunately, the observations that were made by professors and students were from too great a distance (10 feet away) in order to be unobtrusive but unable to code the precise type of cell phone texting/scrolling that was occurring.

The Microsimulation Model for Assessing the Impact of Inbound Traffic Flows for Container Terminals Located near City Centers

The growth of container transport places increasing demand on traffic, especially in situations where container terminals are located near the city centers. The main problem is traffic congestion on networks caused by the integration of Heavy-Duty Vehicles and urban traffic flows. The main objective is to identify the critical traffic parameters which cause negative organizational and environmental impacts on the existing and future traffic demand. A micro-level traffic simulation model was implemented for the testing of the proposed framework-based supply, demand, and control layers. The model was generated and calibrated based on the example of a mid-size Container Terminal “Brajdica” and the City of Rijeka, Croatia. The results indicate that the critical parameters are Queue Length on the approach road to the Container Terminal and the Stop Delay on the main city corridor. High values of these parameters cause negative effects on the environment because of increased fuel consumption and the generation of extra pollution. Due to this problem, a sensitivity analysis of the traffic system performance has been conducted, with a decrement of Terminal Gate Time distribution by 10%. After re-running simulations, the results indicate the impact of subsequent variation in Terminal Gate Time on the decrease of critical parameters, fuel consumption, and vehicle pollution.

Theory of Time-Resolved Optical Conductivity of Superconductors: Comparing Two Methods for Its Evaluation

Time-resolved optical conductivity is an often used tool to interrogate quantum materials driven out of equilibrium. Theoretically calculating this observable is a complex topic with several approaches discussed in the literature. Using a nonequilibrium Keldysh formalism and a functional derivative approach to the conductivity, we present a comparison of two particular approaches to the calculation of the optical conductivity and their distinguishing features, as applied to a pumped superconductor. The two methods are distinguished by the relative motion of the probe and gate times; either the probe or gate time is kept fixed while the other is swept. We find that both the methods result in same qualitative features of the time-resolved conductivity after pump is over. However, calculating the conductivity by keeping the gate fixed removes artifacts inherent to the other method. We provide software that, based on data for the first method, is able to construct the second approach.

Investigating the lower bound of minimum gate times using optimal control

Motivated by a bound derived in a recent work [C. Arenz, B. Russell, D. Burgarth and H. Rabitz, New J. Phys. 19 (2017) 103015], we apply optimal control theory to the dynamics of qubit systems, with the goal of investigating the lower bound of minimum gate times. In practice, we not only need to reach the desired unitary gates but we need to do so in a reasonable time (below the typical decoherence time). Therefore, we employ the recently introduced lower bound to estimate the minimum gate time and resort to numerical gate optimization in order to study the tightness of the obtained bound and our findings verify the relationship between the internal Hamiltonian and the minimum evolution time remarkably well. Finally, we discuss both challenges and ways forward for obtaining the same efficacy under realistic conditions.

Eletrocardiogram gate time in patients with thoracic pain in the emergency

ABSTRACT Objective: to identify electrocardiogram gate time in patients with chest pain in the emergency room. Method: integrative review, using PVO technique, carried out in February 2017, in the VHL Portal and Medline, Web of Science, ScieLO and CIHNAL sites, using the descriptors Chest Pain, Electrocardiography, Emergencies, identified in the MeSH, in the title CINAHL , coinciding with the DeCS, using the Boolean operator AND in all associations. Results: according to the search strategies, ten articles with origin in developed countries and only one Brazilian were identified. Conclusion: the literature defines that the electrocardiogram for patients with chest pain in the emergency room should be done within ten minutes. There is a need to develop further studies on the performance of the ECG in prehospital care in order to carry out conducts directed to cardiac disorders. Descritores: Angina Pectoris; Emergencies; Electrocardiography; Nursing Care; Emergency Nursing; ST Elevation Myocardial Infarction.RESUMOObjetivo: identificar o tempo porta eletrocardiograma em pacientes com dor torácica na emergência. Método: revisão integrativa, utilizando técnica PVO, realizada em fevereiro de 2017, no Portal da BVS e nos sites Medline, Web of Science, ScieLo e CIHNAL, com o uso dos descritores dor no peito, eletrocardiografia, emergências, identificados no MeSH, no título CINAHL, coincidindo com os DeCS, utilizando o operador booleano AND em todas as associações. Resultados: segundo as estratégias de busca, identificaram-se dez artigos de origem em países desenvolvidos e somente um brasileiro. Conclusão: a literatura define que a realização do eletrocardiograma para pacientes com dor torácica na emergência deve ser feita em até dez minutos. Há a necessidade de se desenvolverem mais estudos sobre a realização do ECG no atendimento pré-hospitalar para se tomarem condutas direcionadas diante a agravos cardiológicos. Descritores: Angina Pectoris; Emergências; Eletrocardiografia; Cuidados de Enfermagem; Enfermagem em Emergência; Infarto do Miocárdio com Supradesnível do Segmento ST. RESUMEN Objetivo: identificar el tiempo puerta-electrocardiograma en pacientes con dolor torácico en la emergencia. Método: revisión integrativa, utilizando técnica PVO, realizada en febrero de 2017 en los servicios, en el Portal de la BVS, y en los sitios, Medline, Web of Science, ScieLo y CIHNAL, con el uso de los descriptores dolor en el pecho, electrocardiografía, emergencias, identificados en el MeSH, en el título CINAHL, coincidiendo con los DeCS, utilizando el operador booleano AND en todas las asociaciones. Resultados: según las estrategias de búsqueda, se identificaron diez artículos, los cuales son de origen en países desarrollados y sólo uno es brasileño. Conclusión: la literatura define que la realización del electrocardiograma para pacientes con dolor torácico en la emergencia debe ser hecha en hasta 10 minutos. Hay la necesidad de desarrollar más estudios sobre la realización del ECG en la atención prehospitalaria para tomar conductas dirigidas ante agravios cardiológicos. Descritores: Angina de Pecho; Urgencias Médicas; Electrocardiografía; Atención en Enfermería; Enfermería de Urgencia; Infarto del Miocardio con Elevación del ST.

Fault-tolerant quantum computing in the Pauli or Clifford frame with slow error diagnostics

We consider the problem of fault-tolerant quantum computation in the presence of slow error diagnostics, either caused by measurement latencies or slow decoding algorithms. Our scheme offers a few improvements over previously existing solutions, for instance it does not require active error correction and results in a reduced error-correction overhead when error diagnostics is much slower than the gate time. In addition, we adapt our protocol to cases where the underlying error correction strategy chooses the optimal correction amongst all Clifford gates instead of the usual Pauli gates. The resulting Clifford frame protocol is of independent interest as it can increase error thresholds and could find applications in other areas of quantum computation.

Design and Implementation of Digital Frequency Meter Based on SCM

The digital frequency meter was a device to detect and display the frequency. In many design complexity, features a variety of electronic devices, the digital frequency meter was one of the essential equipment. It was widely used in various fields. The core of the frequency meter is AT89C51 microcontroller. It used SCM counting and timing functions to achieve the measurement pulse within a certain gate time, and it uses LED digital display tube displays the measured frequency. The device has a high frequency accuracy measurement, real time, and it has a simple, easy to carry, strong expansion capability, a wide range.

Dynamical decoupling of random telegraph noise in a two-qubit gate

Controlling the dynamics of entanglement and preventing its disappearance are central requisites for any implementation of quantum information processing. Solid state qubits are frequently affected by random telegraph noise due to bistable impurities of different nature coupled to the device. In this paper, we investigate the possibility to achieve an efficient universal two-qubit gate in the presence of random telegraph noise by periodic dynamical decoupling. We find an analytic form of the gate error as a function of the number of applied pulses valid when the gate time is much shorter then the telegraphic process correlation time. The analysis is further supplemented by exact numerical results demonstrating the feasibility of a highly-efficient universal two-qubit gate.