Tunable slowing, storing and releasing of a weak microwave field

We study the slowing, storing and releasing of microwave pulses in a superconducting circuits composed of two coplanar waveguide resonators and a superconducting transmon-type qubit. The quantum interference analogy to electromagnetically induced transparency is created in two coupled resonators. By tuning the resonance frequency of the transmon, we dynamically tune the effective coupling between the resonators. Via the modulation of the coupling, we show the tunable true time delay of microwave pulses at the single-photon level. We also store the microwave field in a high-Q resonator and release the signal from it to the output port. Our scheme promises applications in both quantum information processing and classical wireless communications.Comment: 16 pages, 9 figures, articl

Factor proportions and international business cycles

Positive investment comovements across OECD economies as observed in the data are difficult to replicate in open-economy real business cycle models, but also vary substantially in degree for individual country-pairs. This paper shows that a two-country stochastic growth model that distinguishes sectors by factor intensity (capital-intensive vs. labor-intensive) gives rise to an endogenous channel of the international transmission of shocks that first, can substantially ameliorate the “quantity anomalies” that mark large open-economy models, and second, generate a cross-sectional prediction that is strongly supported by the data: investment correlations tend to be stronger for country-pairs that exhibit greater disparity in the factor-intensity of trade. In addition, three new pieces of evidence support the central mechanism: (1) the production composition of capital versus labor-intensive sectors changes over the business cycle; (2) the prices of capital-intensive goods and labor-intensive goods are respectively, procyclical and countercyclical; (3) a positive productivity shock in the U.S. tilts the composition of production towards capital-intensive sectors in other countries

Effects of corrective feedback on EFL speaking task complexity in China’s university classroom

Corrective feedback (CF) and task complexity are two important pedagogical topics in second language acquisition research in recent years, but there is few research investigating effects of CF on speaking task complexity in China’s university classroom settings. This research, through conducting different versions of speaking task experiments among 24 university students in China, explores the effect of teachers’ CF on English as a Foreign Language (EFL) speaking task complexity. According to the analysis of first-hand data, this research finds CF has different effects on EFL oral production with different task complexity. In simple speaking task, the effects of five kinds of CF (from largest to smallest) are listed as follows: clarification quest, metalinguistic feedback, recast, repetition and confirmation check. Regarding complex speaking task, the effects of five categorized CF are ranked from largest to smallest as follows: metalinguistic feedback, confirmation check, recast, clarification request and repetition. Improving to provide CF in pedagogical practice is an important contribution to promote EFL speaking task, so, on the basis of above research results, appropriate ways and forms of providing CF are expected to promote efficiency of CF in EFL classroom under the context of Chinese university classroom

Effective website for educational institution

This paper examines the current status of a New Zealand educational institution’s website and makes a comparison among 44 samples. Two main sections have been contained in this research, secondary resource collection and observation. The aim of this research is to raise the awareness of this organisation and to attract potential students from the Chinese market by improve the organisation’s official website. This is desk research which has made use of qualitative methods. The results of the secondary resource collection mainly illustrate the general concepts of website design, the key factors of the education website, and Chinese web page preferences. The results from observation of 44 samples have been divided into two aspects, functionality and content. Most educational institution website pages are functional, while their online communication channels are basically limited to social media links; from the content point of view, school websites with Chinese versions generally have poor translations, and existing educational institution website samples can provide the information that the viewer needs through different presentation methods. These differences are explained in the discussion section. In conclusion, it suggested that in the current stage, educational institution websites could gain development by diversifying their communication channels and information presentation

Composition and growth effects of the current account: a synthesized portfolio view

This paper analyzes a useful accounting framework that breaks down the current account to two components: a composition effect and a growth effect. We show that past empirical evidence, which strongly supports the growth-eect as the main driver of current account dynamics, is mis- conceived. The remarkable empirical success of the growth eect is driven by the dominance of the cross-sectional variation, which, under conditions met by the data, is generated by an accounting approximation. In contrast to previous ndings that the portfolio share of net foreign assets to total assets is constant in a country, both our theoretical and empirical results support a highly persistent process or a unit root process, with some countries displaying a trend. Finally, we reestablish the composition effect as the quantitatively dominant driving force of current account dynamics in the past data

Solid state optical interconnect between distant superconducting quantum chips

We propose a design for a quantum interface exploiting the electron spins in crystals to swap the quantum states between the optical and microwave. Using sideband driving of a superconducting flux qubit and a combined cavity/solid-state spin ensemble Raman transition, we demonstrate how a stimulated Raman adiabatic passage (STIRAP)-type operation can swap the quantum state between a superconducting flux qubit and an optical cavity mode with a fidelity higher than $90\%$. We further consider two distant superconducting qubits with their respective interfaces joined by an optical fiber and show a quantum transfer fidelity exceeding $90\%$ between the two distant qubits.Comment: 5 figures, 5 page

Factor Proportions and International Business Cycles

Positive investment comovements across OECD economies as observed in the data are difficult to replicate in open-economy real business cycle models, but also vary substantially in degree for individual country-pairs. This paper shows that a two-country stochastic growth model that distinguishes sectors by factor intensity (capital-intensive vs. labor-intensive) gives rise to an endogenous channel of the international transmission of shocks that first, can substantially ameliorate the "quantity anomalies" that mark large open-economy models, and second, generate a cross-sectional prediction that is strongly supported by the data: investment correlations tend to be stronger for country-pairs that exhibit greater disparity in the factor-intensity of trade. In addition, three new pieces of evidence support the central mechanism: (1) the production composition of capital versus labor-intensive sectors changes over the business cycle; (2) the prices of capital-intensive goods and labor-intensive goods are respectively, procyclical and countercyclical; (3) a positive productivity shock in the U.S. tilts the composition of production towards capital-intensive sectors in other countries.International business cycles, international comovement, composition effects

Detection of a weak magnetic field via cavity enhanced Faraday rotation

We study the sensitive detection of a weak static magnetic field via Faraday rotation induced by an ensemble of spins in a bimodal degenerate microwave cavity. We determine the limit of the resolution for the sensitivity of the magnetometry achieved using either single-photon or multiphoton inputs. For the case of a microwave cavity containing an ensemble of Nitrogen-vacancy defects in diamond, we obtain a magnetometry sensitivity exceeding 0.5~\text{\nano\tesla}/\sqrt{\text{\hertz}}, utilizing a single photon probe field, while for a multiphoton input we achieve a sensitivity about 1 \text{\femto\tesla}/\sqrt{\text{\hertz}}, using a coherent probe microwave field with power of P_\text{in}=1~\text{\nano\watt}.Comment: 8 pages, 7 figure