207 research outputs found
QCD phase transition at real chemical potential with canonical approach
We study the finite density phase transition in the lattice QCD at real
chemical potential. We adopt canonical approach and the canonical partition
function is constructed for Nf=2 QCD. After derivation of the canonical
partition function we calculate observables like the pressure, the quark number
density, its second cumulant and the chiral condensate as a function of the
real chemical potential. We covered a wide range of temperature region starting
from the confining low to the deconfining high temperature. We observe signals
for the deconfinement and the chiral restoration phase transition at real
chemical potential below Tc starting from the confining phase.Comment: 15 pages, 20 figure
All-microwave manipulation of superconducting qubits with a fixed-frequency transmon coupler
All-microwave control of fixed-frequency superconducting quantum computing
circuits is advantageous for minimizing the noise channels and wiring costs.
Here we introduce a swap interaction between two data transmons assisted by the
third-order nonlinearity of a coupler transmon under a microwave drive. We
model the interaction analytically and numerically and use it to implement an
all-microwave controlled-Z gate. The gate based on the coupler-assisted swap
transition maintains high drive efficiency and small residual interaction over
a wide range of detuning between the data transmons.Comment: 12 pages, 8 figure
New readout and data-acquisition system in an electron-tracking Compton camera for MeV gamma-ray astronomy (SMILE-II)
For MeV gamma-ray astronomy, we have developed an electron-tracking Compton
camera (ETCC) as a MeV gamma-ray telescope capable of rejecting the radiation
background and attaining the high sensitivity of near 1 mCrab in space. Our
ETCC comprises a gaseous time-projection chamber (TPC) with a micro pattern gas
detector for tracking recoil electrons and a position-sensitive scintillation
camera for detecting scattered gamma rays. After the success of a first balloon
experiment in 2006 with a small ETCC (using a 101015 cm
TPC) for measuring diffuse cosmic and atmospheric sub-MeV gamma rays (Sub-MeV
gamma-ray Imaging Loaded-on-balloon Experiment I; SMILE-I), a (30 cm)
medium-sized ETCC was developed to measure MeV gamma-ray spectra from celestial
sources, such as the Crab Nebula, with single-day balloon flights (SMILE-II).
To achieve this goal, a 100-times-larger detection area compared with that of
SMILE-I is required without changing the weight or power consumption of the
detector system. In addition, the event rate is also expected to dramatically
increase during observation. Here, we describe both the concept and the
performance of the new data-acquisition system with this (30 cm) ETCC to
manage 100 times more data while satisfying the severe restrictions regarding
the weight and power consumption imposed by a balloon-borne observation. In
particular, to improve the detection efficiency of the fine tracks in the TPC
from 10\% to 100\%, we introduce a new data-handling algorithm in
the TPC. Therefore, for efficient management of such large amounts of data, we
developed a data-acquisition system with parallel data flow.Comment: 11 pages, 24 figure
The Cerebellum Is a Common Key for Visuospatial Execution and Attention in Parkinsonās Disease
Cognitive decline affects the clinical course in patients with Parkinsonās disease (PD) and contributes to a poor prognosis. However, little is known about the underlying network-level abnormalities associated with each cognitive domain. We aimed to identify the networks related to each cognitive domain in PD using resting-state functional magnetic resonance imaging (MRI). Forty patients with PD and 15 normal controls were enrolled. All subjects underwent MRI and the Mini-Mental State Examination. Furthermore, the cognitive function of patients with PD was assessed using the Montreal Cognitive Assessment (MoCA). We used independent component analysis of the resting-state functional MRI for functional segmentation, followed by reconstruction to identify each domain-related network, to predict scores in PD using multiple regression models. Six networks were identified, as follows: the visuospatial-executive-domain-related network (R2 = 0.54, p < 0.001), naming-domain-related network (R2 = 0.39, p < 0.001), attention-domain-related network (R2 = 0.86, p < 0.001), language-domain-related network (R2 = 0.64, p < 0.001), abstraction-related network (R2 = 0.10, p < 0.05), and orientation-domain-related network (R2 = 0.64, p < 0.001). Cerebellar lobule VII was involved in the visuospatial-executive-domain-related and attention-domain-related networks. These two domains are involved in the first three listed nonamnestic cognitive impairment in the diagnostic criteria for PD with dementia (PDD). Furthermore, Brodmann area 10 contributed most frequently to each domain-related network. Collectively, these findings suggest that cerebellar lobule VII may play a key role in cognitive impairment in nonamnestic types of PDD
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