The current and the charge noise of a single-electron transistor in the regime of large charge fluctuations out of equilibrium

By using the Schwinger-Keldysh approach, we evaluate the current noise and the charge noise of the single-electron transistor (SET) in the regime of large charge fluctuations caused by large tunneling conductance. Our result interpolates between previous theories; the "orthodox" theory and the "co-tunneling theory". We find that the life-time broadening effect suppresses the Fano factor below the value estimated by the previous theories. We also show that the large tunnel conductance does not reduce the energy sensitivity so much. Our results demonstrate quantitatively that SET electrometer can be used as the high-sensitivity and high-speed device for quantum measurements.Comment: 6 pages, 3 figures, Proccedings of International Symposium on Mesoscopic Superconductivity and Spintronics (MS+S2002

The Mixed State of Charge-Density-Wave in a Ring-Shaped Single Crystals

Charge-density-wave (CDW) phase transition in a ring-shaped crystals, recently synthesized by Tanda et al. [Nature, 417, 397 (2002)], is studied based on a mean-field-approximation of Ginzburg-Landau free energy. It is shown that in a ring-shaped crystals CDW undergoes frustration due to the curvature (bending) of the ring (geometrical frustration) and, thus, forms a mixed state analogous to what a type-II superconductor forms under a magnetic field. We discuss the nature of the phase transition in the ring-CDW in relation to recent experiments.Comment: 6 pages, 4 figure

The effect of charge fluctuation on a normal-superconducting-normal single-electron transistor

We theoretically investigate quantum fluctuation of charge between even and odd states of a normal-superconducting-normal single-electron tunneling transistor. It is shown that due to the superconducting gap, the charge fluctuation in the Coulomb blockade regime for even state is larger than that for odd state. We show that large energy correction in the former regime caused by charge fluctuation can be explained by considering the charging energy renormalization.Comment: 4 pages, 3 figures, prepared for Proccedings of International Symposium on Superconducting Device Physics (SDP 2001

The effect of large quantum fluctuation on the noise of a single-electron transistor

We theoretically investigate the noise of a single-electron transistor in the regime of large quantum fluctuation of charge out of equilibrium. We show that the charge noise is suppressed due to the charge renormalization caused by the quantum fluctuation. However the fluctuation is not strong enough to wash out the charge quantization. We find that the renormalization effect reduces the performance of a single-electron electrometer.Comment: 3 pages, 2 figures: proceedings of the 23rd International Conference on Low Temperature Physics, (August 20-27, 2002, Hiroshima, Japan

ベトナム農村部および都市部における食事摂取状況調査

The purpose of the present study is to clarify the existence of problems related to eating habits and nutritional insufficiency in Vietnamese urban and farm village inhabitants, and to get information that can aid in making nutritional improvements. From the food-frequency questionnaire and household economy survey, we learned that households in a Vietnamese farm village are different from those in an urban region in several ways: 1) they have relatively big families, 2) there are few seniors, 3) they have few kinds of kitchen utensils, 4) they dont have electrical appliances such as refrigerators and electric rice cookers, 5) they use well water and rainwater for washing, drinking and cooking, 6) their staple food is rice, 7) they tend not to eat tubers, peanuts, corn, and wheat, 8) they customarily eat pork and chicken but hardly consume any beef or dairy products, 9) they eat tofu comparatively frequently, 10) they eat vegetables every day but do not eat fruits frequently, 11) the average body mass index (BMI) of residents between 10-19 years old was low: 16.2±2.0. Using these results, we considered the risk of inhabitants of the farm village area falling into malnutrition during periods of economic growth. No apparent risks were observed in the urban region. Nutrition education and nourishment guidance for the inhabitants in the farm village to improve their nutritional status are necessary. In particular, it is necessary to increase the intake of potatoes, corn, wheat and grains other than rice in adulthood, and it is necessary for infants to take more calories and animal protein

ACOUSTIC SHEAR IMPEDANCE OF SUPERFLUID 3He-B

Une expression de l'impédance acoustique du mode transverse est obtenue dans le régime ω ≪ 2Ɗ et ωτ = ∞ pour la phase B de 3He superfluide.An expression for the acoustic shear impedance of the superfluid B phase of 3He is obtained for ω 2Ɗ and ω τ = ∞