618 research outputs found
On a family of quotients of Fermat curves
Let Fx be the N-th Fermat curve defined by the equation: ux+vn=1. For a pair (r, s) of positive integers such that r+s≦N-1 and g.c.d (r, s, N)=1, we denote by F(r, s) the quotient of Fx defined by the equation: ..
Measurement of the Noise Spectrum Using a Multiple-Pulse Sequence
A method is proposed for obtaining the spectrum for noise that causes the
phase decoherence of a qubit directly from experimentally available data. The
method is based on a simple relationship between the spectrum and the coherence
time of the qubit in the presence of a pi-pulse sequence. The relationship is
found to hold for every system of a qubit interacting with the classical-noise,
bosonic, and spin baths.Comment: 8 pages (4 pages + 4 pages Supplemental material), 1 figur
Ambipolar transport in bulk crystals of a topological insulator by gating with ionic liquid
We report that the ionic-liquid gating of bulk single crystals of a
topological insulator can control the type of the surface carriers and even
results in ambipolar transport. This was made possible by the use of a highly
bulk-insulating BiSbTeSe2 system where the chemical potential is located close
to both the surface Dirac point and the middle of the bulk band gap. Thanks to
the use of ionic liquid, the control of the surface chemical potential by
gating was possible on the whole surface of a bulk three-dimensional sample,
opening new experimental opportunities for topological insulators. In addition,
our data suggest the existence of a nearly reversible electrochemical reaction
that causes bulk carrier doping into the crystal during the ionic-liquid gating
process.Comment: 7 pages, 6 figures, 2 tables; significantly expanded version to fully
discuss the gating process and its side effects; published in PR
Ground data system for Space Flyer Unit (SFU)
The Space Flyer Unit (SFU) is an unmanned, multi-purpose, retrievable and reusable space platform. The first mission of SFU (SFU-1) will be launched by NASDA's H-2 launch vehicle in early 1995 and retrieved by NASA's Space Shuttle after several months in orbit. Two Japanese ground stations, several ground stations belonging to NASA, and a ground station in Chile will be used for tracking of SFU-1. The control center of SFU-1 is the Sagamihara Operations Center (SOC) of ISAS located in Sagamihara, Japan. This paper describes the tracking and data acquisition network for SFU-1, the configuration and design policy of the SFU operations control system, and data processing schemes used for mission operations of SFU
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