Coupling Circuit Resonators Among Themselves and To Nitrogen-Vacancy Centers in Diamond

We propose a scheme to couple NV centers in diamond through coplanar waveguide resonators. The central conductor of the resonator is split into several pieces which are coupled strongly with each other via simple capacitive junctions or superconducting Josephson junctions. The NV centers are then put at the junctions. The discontinuity at the junctions induces a large local magnetic field, with which the NV centers are strongly coupled to the circuit resonator. The coupling strength $g$ between the resonator and the NV center is of order of $g/2\pi\sim 1$--30\unit{MHz}.Comment: 4 pages; 3 figures; several typos corrected; figure 1 regenerate

Large-Scale Schr\"odinger-Cat States and Majorana Bound States in Coupled Circuit-QED Systems

We have studied the low-lying excitations of a chain of coupled circuit-QED systems, and report several intriguing properties of its two nearly degenerate ground states. The ground states are Schr\"odinger cat states at a truly large scale, involving maximal entanglement between the resonator and the qubit, and are mathematically equivalent to Majorana bound states. With a suitable design of physical qubits, they are protected against local fluctuations and constitute a non-local qubit. Further, they can be probed and manipulated coherently by attaching an empty resonator to one end of the circuit-QED chain.Comment: 5 pages; 2 figures; incorrect references corrected; typos correcte

Variational study of a two-level system coupled to a harmonic oscillator in a ultrastrong coupling regime

The nonclassical behaviors of a two-level system coupled to a harmonic oscillator is investigated in the ultrastrong coupling regime. We revisit the variational solution of the ground state and find that the existing solution do not account accurately for nonclassical effects such squeezing. We suggest a new trial wave function and demonstrate that it has an excellent accuracy on the quantum correlation effects as well as on energy.Comment: 4 pages; 3 figures; to appear in Phys. Rev.

Lattice strain-enhanced exsolution of nanoparticles in thin films

This work was supported by the National Research Foundation (NRF) Grant funded by the Korean Government (MSIP Grant No.2016R 1D1A1B 03933253). J.T.S.I. thanks the EPSRC for support on emergent nanomaterials through grant EP/R023522/1. H.H. and S.S.P.P. acknowledge the support by the Max Planck Society (MPG).Nanoparticles formed on oxide surfaces are of key importance in many fields such as catalysis and renewable energy. Here, we control B-site exsolution via lattice strain to achieve a high degree of exsolution of nanoparticles in perovskite thin films: more than 1100 particles μm−2 with a particle size as small as ~5 nm can be achieved via strain control. Compressive-strained films show a larger number of exsolved particles as compared with tensile-strained films. Moreover, the strain-enhanced in situ growth of nanoparticles offers high thermal stability and coking resistance, a low reduction temperature (550 oC), rapid release of particles, and wide tunability. The mechanism of lattice strain-enhanced exsolution is illuminated by thermodynamic and kinetic aspects, emphasizing the unique role of the misfit-strain relaxation energy. This study provides critical insights not only into the design of new forms of nanostructures but also applications ranging from catalysis, energy conversion/storage, nano-composites, nano-magnetism, to nano-optics.Publisher PDFPeer reviewe

Characteristics, Outcomes and Predictors of Long-Term Mortality for Patients Hospitalized for Acute Heart Failure: A Report From the Korean Heart Failure Registry

BACKGROUND AND OBJECTIVES: Acute heart failure (AHF) is associated with a poor prognosis and it requires repeated hospitalizations. However, there are few studies on the characteristics, treatment and prognostic factors of AHF. The aims of this study were to describe the clinical characteristics, management and outcomes of the patients hospitalized for AHF in Korea. SUBJECTS AND METHODS: We analyzed the clinical data of 3,200 hospitalization episodes that were recorded between June 2004 and April 2009 from the Korean Heart Failure (KorHF) Registry database. The mean age was 67.6±14.3 years and 50% of the patients were female. RESULTS: Twenty-nine point six percent (29.6%) of the patients had a history of previous HF and 52.3% of the patients had ischemic heart disease. Left ventricular ejection fraction (LVEF) was reported for 89% of the patients. The mean LVEF was 38.5±15.7% and 26.1% of the patients had preserved systolic function (LVEF ≥50%), which was more prevalent in the females (34.0% vs. 18.4%, respectively, p<0.001). At discharge, 58.6% of the patients received beta-blockers (BB), 53.7% received either angiotensin converting enzyme-inhibitors or angiotensin receptor blockers (ACEi/ARB), and 58.4% received both BB and ACEi/ARB. The 1-, 2-, 3- and 4-year mortality rates were 15%, 21%, 26% and 30%, respectively. Multivariate analysis revealed that advanced age {hazard ratio: 1.023 (95% confidence interval: 1.004-1.042); p=0.020}, a previous history of heart failure {1.735 (1.150-2.618); p=0.009}, anemia {1.973 (1.271-3.063); p=0.002}, hyponatremia {1.861 (1.184-2.926); p=0.007}, a high level of serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) {3.152 (1.450-6.849); p=0.004} and the use of BB at discharge {0.599 (0.360-0.997); p=0.490} were significantly associated with total death. CONCLUSION: We present here the characteristics and prognosis of an unselected population of AHF patients in Korea. The long-term mortality rate was comparable to that reported in other countries. The independent clinical risk factors included age, a previous history of heart failure, anemia, hyponatremia, a high NT-proBNP level and taking BB at discharge.ope

The Relation of Menarcheal Age to Anthropometric Profiles in Korean Girls

The aim of this study was to represent the trend of early menarche and to assess the association of age at menarche with anthropometric profiles of Korean children and adolescents. A cross sectional survey was conducted with 13,371 girls aged 10 to 18 yr, recruited nationwide from April, 2005 to March, 2006. Height, weight and waist circumference of the subjects were measured; and the subjects self-reported their ages at menarche. We found that the menarcheal girls were taller (P<0.05 for the girls between 10 and 14 yr) and heavier (P<0.05 for the girls between 10 and 18 yr) than non-menarcheal ones. Menarcheal girls also showed higher body mass index (BMI), and greater waist circumference than non-menarcheal ones. Significant differences were represented according to the age at menarche in terms of BMI, waist circumference, % body fat mass, waist hip ratio and neck circumference as well as height and weight (P<0.05). In conclusion, girls who matured early were taller and heavier in early adolescence than those who matured later

Influence of Lamina Terminalis Fenestration on the Occurrence of the Shunt-Dependent Hydrocephalus in Anterior Communicating Artery Aneurysmal Subarachnoid Hemorrhage

Recently, it was reported that fenestration of the lamina terminalis (LT) may reduce the incidence of shunt-dependent hydrocephalus in aneurysmal subarachnoid hemorrhage (SAH). The authors investigated the efficacy of the LT opening on the incidence of shunt-dependent hydrocephalus in the ruptured anterior communicating artery (ACoA) aneurysms. The data of 71-ruptured ACoA aneurysm patients who underwent aneurysmal clipping in acute stage were reviewed retrospectively. Group I (n=36) included the patients with microsurgical fenestration of LT during surgery, Group II (n=35) consisted of patients in whom fenestration of LT was not feasible. The rate of shunt-dependent hydrocephalus was compared between two groups by logistic regression to control for confounding factors. Ventriculo-peritoneal shunts were performed after aneurysmal obliteration in 18 patients (25.4%). The conversion rates from acute hydrocephalus on admission to chronic hydrocephalus in each group were 29.6% (Group I) and 58.8% (Group II), respectively. However, there was no significant correlation between the microsurgical fenestration and the rate of occurrence of shunt-dependent hydrocephalus (p>0.05). Surgeons should carefully decide the concomitant use of LT fenestration during surgery for the ruptured ACoA aneurysms because of the microsurgical fenestration of LT can play a negative role in reducing the incidence of chronic hydrocephalus