145,824 research outputs found
Renormalization analysis of intermittency in two coupled maps
The critical behavior for intermittency is studied in two coupled
one-dimensional (1D) maps. We find two fixed maps of an approximate
renormalization operator in the space of coupled maps. Each fixed map has a
common relavant eigenvaule associated with the scaling of the control parameter
of the uncoupled one-dimensional map. However, the relevant ``coupling
eigenvalue'' associated with coupling perturbation varies depending on the
fixed maps. These renormalization results are also confirmed for a
linearly-coupled case.Comment: 11 pages, RevTeX, 2 eps figure
Quaternion Electromagnetism and the Relation with 2-Spinor Formalism
By using complex quaternion, which is the system of quaternion representation
extended to complex numbers, we show that the laws of electromagnetism can be
expressed much more simply and concisely. We also derive the quaternion
representation of rotations and boosts from the spinor representation of
Lorentz group. It is suggested that the imaginary 'i' should be attached to the
spatial coordinates, and observe that the complex conjugate of quaternion
representation is exactly equal to parity inversion of all physical quantities
in the quaternion. We also show that using quaternion is directly linked to the
two-spinor formalism. Finally, we discuss meanings of quaternion, octonion and
sedenion in physics as n-fold rotationComment: Version published in journal Universe (2019
Quantum Dynamics for de Sitter Radiation
We revisit the Hamiltonian formalism for a massive scalar field and study the
particle production in a de Sitter space. In the invariant-operator picture the
time-dependent annihilation and creation operators are constructed in terms of
a complex solution to the classical equation of motion for the field and the
Gaussian wave function for each Fourier mode is found which is an exact
solution to the Schr\"odinger equation. The in-out formalism is reformulated by
the annihilation and creation operators and the Gaussian wave functions. The de
Sitter radiation from the in-out formalism differs from the Gibbons-Hawking
radiation in the planar coordinates, and we discuss the discrepancy of the
particle production by the two methodComment: LaTex 12 pages, no figure; CosPA2011, Peking Univ., Oct. 28-31, 2011;
references added; to be published in International Journal of Modern Physics:
Conference Serie
Steering effects on growth instability during step-flow growth of Cu on Cu(1,1,17)
Kinetic Monte Carlo simulation in conjunction with molecular dynamics
simulation is utilized to study the effect of the steered deposition on the
growth of Cu on Cu(1,1,17). It is found that the deposition flux becomes
inhomogeneous in step train direction and the inhomogeneity depends on the
deposition angle, when the deposition is made along that direction. Steering
effect is found to always increase the growth instability, with respect to the
case of homogeneous deposition. Further, the growth instability depends on the
deposition angle and direction, showing minimum at a certain deposition angle
off-normal to (001) terrace, and shows a strong correlation with the
inhomogeneous deposition flux. The increase of the growth instability is
ascribed to the strengthened step Erlich Schwoebel barrier effects that is
caused by the enhanced deposition flux near descending step edge due to the
steering effect.Comment: 5 page
Propagation of fluctuations in interaction networks governed by the law of mass action
Using an example of physical interactions between proteins, we study how
perturbations propagate in interconnected networks whose equilibrium state is
governed by the law of mass action. We introduce a comprehensive matrix
formalism which predicts the response of this equilibrium to small changes in
total concentrations of individual molecules, and explain it using a heuristic
analogy to a current flow in a network of resistors. Our main conclusion is
that on average changes in free concentrations exponentially decay with the
distance from the source of perturbation. We then study how this decay is
influenced by such factors as the topology of a network, binding strength, and
correlations between concentrations of neighboring nodes. An exact analytic
expression for the decay constant is obtained for the case of uniform
interactions on the Bethe lattice. Our general findings are illustrated using a
real biological network of protein-protein interactions in baker's yeast with
experimentally determined protein concentrations.Comment: 4 pages; 2 figure
Production of the pentaquark in scattering
We study and processes
for both of the positive and negative parities of the . Employing
the effective chiral Lagrangians for the and interactions, we
calculate differential cross sections as well as total cross sections for the
and reactions. The total
cross sections for the positive-parity turn out to be approximately
ten times larger than those for the negative parity in the range of
the CM energy . The results are
rather sensitive to the mechanism of exchanges in the -- channel.Comment: 9 pages and 11 figure
Electronic structures of layered perovskite Sr2MO4 (M=Ru, Rh, and Ir)
We investigated the electronic structures of the two-dimensional layered
perovskite Sr\textit{M}O (\textit{M}=4\textit{d} Ru, 4\textit{d}
Rh, and 5\textit{d} Ir) using optical spectroscopy and polarization-dependent O
1\textit{s} x-ray absorption spectroscopy. While the ground states of the
series of compounds are rather different, their optical conductivity spectra
exhibit similar interband transitions, indicative of the
common electronic structures of the 4\textit{d} and 5\textit{d} layered oxides.
The energy splittings between the two orbitals, ,
and , are about 2 eV, which is much larger
than those in the pseudocubic and 3\textit{d} layered perovskite oxides. The
electronic properties of the Sr\textit{M}O compounds are discussed
in terms of the crystal structure and the extended character of the 4\textit{d}
and 5\textit{d} orbitals
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