384 research outputs found
Spin Fluctuation Induced Dephasing in a Mesoscopic Ring
We investigate the persistent current in a hybrid Aharonov-Bohm ring -
quantum dot system coupled to a reservoir which provides spin fluctuations. It
is shown that the spin exchange interaction between the quantum dot and the
reservoir induces dephasing in the absence of direct charge transfer. We
demonstrate an anomalous nature of this spin-fluctuation induced dephasing
which tends to enhance the persistent current. We explain our result in terms
of the separation of the spin from the charge degree of freedom. The nature of
the spin fluctuation induced dephasing is analyzed in detail.Comment: 4 pages, 4 figure
Design and Realization of Multiplexing System for Fixed/Mobile Next-Generation Broadcasting Service in Network Free Environment
The Current broadcasting enviroment is constally evolving in order to meet the various needs of the viewer such as ColorTV, 3D, HD, UHD TV serivce. And they want to broadcasting the same quality in the fixed and mobile enviroment for high definition braodcasting serive. In this paper, we presnet a design and implementation of muilplexing system for fixed/mobile next generation broadcasting service in network free enivorment. Network free means receive both the broadcasting channel and communication chennel for various TV service. We introduce method to provide next generation convergence broadcating servies based on european standard which can transmit UHD content in network free envieroment. As a result to this paper, we analyze the characteristics of the recieved signal from the commerical receiver device
Anti-Kondo resonance in transport through a quantum wire with a side-coupled quantum dot
An interacting quantum dot side-coupled to a perfect quantum wire is studied.
Transport through the quantum wire is investigated by using an exact sum rule
and the slave-boson mean field treatment. It is shown that the Kondo effect
provides a suppression of the transmission due to the destructive interference
of the ballistic channel and the Kondo channel. At finite temperatures,
anti-resonance behavior is found as a function of the quantum dot level
position, which is interpreted as a crossover from the high temperature Kondo
phase to the low temperature charge fluctuation phase.Comment: 4 pages Revtex, 3 eps figure
Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube
We have studied the afterpulse of a hemispherical photomultiplier tube for an
upcoming reactor neutrino experiment. The timing, the amplitude, and the rate
of the afterpulse for a 10 inch photomultiplier tube were measured with a 400
MHz FADC up to 16 \ms time window after the initial signal generated by an LED
light pulse. The time and amplitude correlation of the afterpulse shows several
distinctive groups. We describe the dependencies of the afterpulse on the
applied high voltage and the amplitude of the main light pulse. The present
data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure
Neutron beam test of CsI crystal for dark matter search
We have studied the response of Tl-doped and Na-doped CsI crystals to nuclear
recoils and 's below 10 keV. The response of CsI crystals to nuclear
recoil was studied with mono-energetic neutrons produced by the
H(p,n)He reaction. This was compared to the response to Compton
electrons scattered by 662 keV -ray. Pulse shape discrimination between
the response to these 's and nuclear recoils was studied, and quality
factors were estimated. The quenching factors for nuclear recoils were derived
for both CsI(Na) and CsI(Tl) crystals.Comment: 21pages, 14figures, submitted to NIM
Multiscale modeling and simulation of nanotube-based torsional oscillators
In this paper, we propose the first numerical study of nanotube-based torsional oscillators via developing a new multiscale model. The edge-to-edge technique was employed in this multiscale method to couple the molecular model, i.e., nanotubes, and the continuum model, i.e., the metal paddle. Without losing accuracy, the metal paddle was treated as the rigid body in the continuum model. Torsional oscillators containing (10,0) nanotubes were mainly studied. We considered various initial angles of twist to depict linear/nonlinear characteristics of torsional oscillators. Furthermore, effects of vacancy defects and temperature on mechanisms of nanotube-based torsional oscillators were discussed
Mesoscopic Fano Effect in a Quantum Dot Embedded in an Aharonov-Bohm Ring
The Fano effect, which occurs through the quantum-mechanical cooperation
between resonance and interference, can be observed in electron transport
through a hybrid system of a quantum dot and an Aharonov-Bohm ring. While a
clear correlation appears between the height of the Coulomb peak and the real
asymmetric parameter for the corresponding Fano lineshape, we need to
introduce a complex to describe the variation of the lineshape by the
magnetic and electrostatic fields. The present analysis demonstrates that the
Fano effect with complex asymmetric parameters provides a good probe to detect
a quantum-mechanical phase of traversing electrons.Comment: REVTEX, 9 pages including 8 figure
The COSINE-100 liquid scintillator veto system
This paper describes the liquid scintillator veto system for the COSINE-100 dark matter experiment and its performance. The COSINE-100 detector consists of eight NaI(Tl) crystals immersed in 2200 L of linear alkylbenzene-based liquid scintillator. The liquid scintillator tags between 65 and 75% of the internal 40K background in the 2–6 keV energy region. We also describe the background model for the liquid scintillator, which is primarily used to assess its energy calibration and threshold
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