2,106 research outputs found
Tensor-optimized shell model for the Li isotopes with a bare nucleon-nucleon interaction
We study the Li isotopes systematically in terms of the tensor-optimized
shell model (TOSM) by using a bare nucleon-nucleon interaction as the AV8'
interaction. The short-range correlation is treated in the unitary correlation
operator method (UCOM). Using the TOSM+UCOM approach, we investigate the role
of the tensor force on each spectrum of the Li isotopes. It is found that the
tensor force produces quite a characteristic effect on various states in each
spectrum and those spectra are affected considerably by the tensor force. The
energy difference between the spin-orbit partner, the p1/2 and p3/2 orbits of
the last neutron, in 5Li is caused by opposite roles of the tensor correlation.
In 6Li, the spin-triplet state in the LS coupling configuration is favored
energetically by the tensor force in comparison with jj coupling shell model
states. In 7,8,9Li, the low-lying states containing extra neutrons in the p3/2
orbit are favored energetically due to the large tensor contribution to allow
the excitation from the 0s orbit to the p1/2 orbit by the tensor force. Those
three nuclei show the jj coupling character in their ground states which is
different from 6Li.Comment: 12 pages, 6 figures. arXiv admin note: text overlap with
arXiv:1108.393
Active Brownian Motion in Threshold Distribution of a Coulomb Blockade Model
Randomly-distributed offset charges affect the nonlinear current-voltage
property via the fluctuation of the threshold voltage of Coulomb blockade
arrays. We analytically derive the distribution of the threshold voltage for a
model of one-dimensional locally-coupled Coulomb blockade arrays, and propose a
general relationship between conductance and the distribution. In addition, we
show the distribution for a long array is equivalent to the distribution of the
number of upward steps for aligned objects of different height. The
distribution satisfies a novel Fokker-Planck equation corresponding to active
Brownian motion. The feature of the distribution is clarified by comparing it
with the Wigner and Ornstein-Uhlenbeck processes. It is not restricted to the
Coulomb blockade model, but instructive in statistical physics generally.Comment: 4pages, 3figure
Effects of a Supermassive Black Hole Binary on a Nuclear Gas Disk
We study influence of a galactic central supermassive black hole (SMBH)
binary on gas dynamics and star formation activity in a nuclear gas disk by
making three-dimensional Tree+SPH simulations. Due to orbital motions of SMBHs,
there are various resonances between gas motion and the SMBH binary motion. We
have shown that these resonances create some characteristic structures of gas
in the nuclear gas disk, for examples, gas elongated or filament structures,
formation of gaseous spiral arms, and small gas disks around SMBHs. In these
gaseous dense regions, active star formations are induced. As the result, many
star burst regions are formed in the nuclear region.Comment: 19 pages, 11 figures, accepted for publication in Ap
A Bilocal Field Theory in Four Dimensions
A bilocal field theory having M\"{o}bius gauge invariance is proposed. In
four dimensions there exists a zero momentum state of the first quantized
model, which belongs to a non-trivial BRS cohomology class. A field theory
lagrangian having a gauge invariance only in four dimensions is constructed.Comment: 13 pages, TEP-9R, LaTe
Quantum Kolmogorov Complexity and Quantum Key Distribution
We discuss the Bennett-Brassard 1984 (BB84) quantum key distribution protocol
in the light of quantum algorithmic information. While Shannon's information
theory needs a probability to define a notion of information, algorithmic
information theory does not need it and can assign a notion of information to
an individual object. The program length necessary to describe an object,
Kolmogorov complexity, plays the most fundamental role in the theory. In the
context of algorithmic information theory, we formulate a security criterion
for the quantum key distribution by using the quantum Kolmogorov complexity
that was recently defined by Vit\'anyi. We show that a simple BB84 protocol
indeed distribute a binary sequence between Alice and Bob that looks almost
random for Eve with a probability exponentially close to 1.Comment: typos correcte
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