40 research outputs found
General treatment of Gaussian trusted noise in continuous variable quantum key distribution
Continuous Variable (CV) quantum key distribution (QKD) is a promising
candidate for practical implementations due to its compatibility with the
existing communication technology. A trusted device scenario assuming that an
adversary has no access to imperfections such as electronic noises in the
detector is expected to provide significant improvement in the key rate, but
such an endeavor so far was made separately for specific protocols and for
specific proof techniques. Here, we develop a simple and general treatment that
can incorporate the effects of Gaussian trusted noises for any protocol that
uses homodyne/heterodyne measurements. In our method, a rescaling of the
outcome of a noisy homodyne/heterodyne detector renders it equivalent to the
outcome of a noiseless detector with a tiny additional loss, thanks to a
noise-loss equivalence well-known in quantum optics. Since this method is
independent of protocols and security proofs, it is applicable to
Gaussian-modulation and discrete-modulation protocols, to the finite-size
regime, and to any proof techniques developed so far and yet to be discovered
as well.Comment: 7 pages, 4 figure
Skeletal myoblast sheet transplantation improves the diastolic function of a pressure-overloaded right heart
ObjectiveThe development of right ventricular dysfunction has become a common problem after surgical repair of complex congenital heart disease. A recent study reported that tissue-engineered skeletal myoblast sheet transplantation improves left ventricular function in patients with dilated and ischemic cardiomyopathy. Therefore myoblast sheet transplantation might also improve ventricular performance in a rat model of a pressure-overloaded right ventricle.MethodsSeven-week-old male Lewis rats underwent pulmonary artery banding. Four weeks after pulmonary artery banding, myoblast sheet transplantation to the right ventricle was performed in the myoblast sheet transplantation group (n = 20), whereas a sham operation was performed in the sham group (n = 20).ResultsFour weeks after performing the procedure, a hemodynamic assessment with a pressure–volume loop showed a compensatory increase in systolic function in both groups. However, only the myoblast sheet transplantation group showed a significant improvement in the diastolic function: end-diastolic pressure (sham vs myoblast sheet transplantation, 10.3 ± 3.1 vs 5.0 ± 3.7 mm Hg; P < .001), time constant of isovolumic relaxation (11.1 ± 2.5 vs 7.6 ± 1.2 ms, P < .001), and end-diastolic pressure–volume relationship (16.1 ± 4.5 vs 7.6 ± 2.4/mL, P < .005). The right ventricular weight and cell size similarly increased in both groups. A histologic assessment demonstrated significantly suppressed ventricular fibrosis and increased capillary density in the myoblast sheet transplantation group in comparison with those in the sham group. Reverse transcription–polymerase chain reaction demonstrated an increased myocardial gene expression of hepatocyte growth factor and vascular endothelial growth factor in the myoblast sheet transplantation group but not in the sham group.ConclusionsSkeletal myoblast sheet transplantation improved the diastolic dysfunction and suppressed ventricular fibrosis with increased capillary density in a rat model of a pressure-overloaded right ventricle. This method might become a novel strategy for the myocardial regeneration of right ventricular failure in patients with congenital heart disease
Blueprint for a Scalable Photonic Fault-Tolerant Quantum Computer
Photonics is the platform of choice to build a modular, easy-to-network
quantum computer operating at room temperature. However, no concrete
architecture has been presented so far that exploits both the advantages of
qubits encoded into states of light and the modern tools for their generation.
Here we propose such a design for a scalable and fault-tolerant photonic
quantum computer informed by the latest developments in theory and technology.
Central to our architecture is the generation and manipulation of
three-dimensional hybrid resource states comprising both bosonic qubits and
squeezed vacuum states. The proposal enables exploiting state-of-the-art
procedures for the non-deterministic generation of bosonic qubits combined with
the strengths of continuous-variable quantum computation, namely the
implementation of Clifford gates using easy-to-generate squeezed states.
Moreover, the architecture is based on two-dimensional integrated photonic
chips used to produce a qubit cluster state in one temporal and two spatial
dimensions. By reducing the experimental challenges as compared to existing
architectures and by enabling room-temperature quantum computation, our design
opens the door to scalable fabrication and operation, which may allow photonics
to leap-frog other platforms on the path to a quantum computer with millions of
qubits.Comment: 38 pages, many figures. Comments welcom
A Report on Overseas Teaching Practicum by Graduate Students in Elementary / Secondary Schools in the United States (III)
The purpose of this report is to examine the significance of the teaching practice in elementary / middle schools in the United States by a group of Japanese graduate students. In Overseas Teaching Practicum held in schools in the State of North Carolina, the United States of America, for a week in September, 2009, the six Japanese graduate students majoring in education planned and gave lessons in some schools in America on Japanese society and culture in English. As a result, it was recognized that the teaching experiences in the international setting could contribute to the enhancement of the teaching skills, international understanding, understanding of home culture, and self-transformation of the participant students. Furthermore, considering the overall achievements of the projects during the past years, some commonalities were identified in the processes and focuses of their lesson planning/implementation, and the changes which took place during the project