2,650 research outputs found
New Einstein-Hilbert-type Action and Superon-Graviton Model(SGM) of Nature
A nonlinear supersymmetric(NLSUSY) Einstein-Hilbert(EH)-type new action for
unity of nature is obtained by performing the Einstein gravity analogue
geomtrical arguments in high symmetry spacetime inspired by NLSUSY. The new
action is unstable and breaks down spontaneously into E-H action with matter in
ordinary Riemann spacetime. All elementary particles except graviton are
composed of the fundamental fermion "superon" of Nambu-Goldstone(NG) fermion of
NLSUSY and regarded as the eigenstates of SO(10) super-Poincar\'e (SP) algebra,
called superon-graviton model(SGM) of nature. Some phenomenological
implications for the low energy particle physics and the cosmology are
discussed. The linearization of NLSUSY including N=1 SGM action is attempted
explicitly to obtain the linear SUSY local field theory, which is equivalent
and renormalizable.Comment: 37 pages, Latex, Based on a talk by K. Shima at International
Conference on Mathematics and Nucler Physics for the 21st Century, March
8-13, 2003, Atomic Energy Authority, Cairo, Egyp
Flexible control of the Peierls transition in metallic C polymers
The metal-semiconductor transition of peanut-shaped fullerene (C)
polymers is clarified by considering the electron-phonon coupling in the uneven
structure of the polymers. We established a theory that accounts for the
transition temperature reported in a recent experiment and also suggests
that is considerably lowered by electron doping or prolonged irradiation
during synthesis. The decrease in is an appealing phenomenon with regard
to realizing high-conductivity C-based nanowires even at low
temperatures.Comment: 3 pages, 3 figure
Torsion-induced persistent current in a twisted quantum ring
We describe the effects of geometric torsion on the coherent motion of
electrons along a thin twisted quantum ring. The geometric torsion inherent in
the quantum ring triggers a quantum phase shift in the electrons' eigenstates,
thereby resulting in a torsion-induced persistent current that flows along the
twisted quantum ring. The physical conditions required for detecting the
current flow are discussed.Comment: 9 pages, 3 figure
Phase Transition of XY Model in Heptagonal Lattice
We numerically investigate the nature of the phase transition of the XY model
in the heptagonal lattice with the negative curvature, in comparison to other
interaction structures such as a flat two-dimensional (2D) square lattice and a
small-world network. Although the heptagonal lattice has a very short
characteristic path length like the small-world network structure, it is
revealed via calculation of the Binder's cumulant that the former exhibits a
zero-temperature phase transition while the latter has the finite-temperature
transition of the mean-field nature. Through the computation of the vortex
density as well as the correlation function in the low-temperature
approximation, we show that the absence of the phase transition originates from
the strong spinwave-type fluctuation, which is discussed in relation to the
usual 2D XY model.Comment: 5 pages, 6 figures, to be published in Europhys. Let
The volume of Gaussian states by information geometry
We formulate the problem of determining the volume of the set of Gaussian
physical states in the framework of information geometry. That is, by
considering phase space probability distributions parametrized by the
covariances and supplying this resulting statistical manifold with the
Fisher-Rao metric. We then evaluate the volume of classical, quantum and
quantum entangled states for two-mode systems showing chains of strict
inclusion
Geometric effects on critical behaviours of the Ising model
We investigate the critical behaviour of the two-dimensional Ising model
defined on a curved surface with a constant negative curvature. Finite-size
scaling analysis reveals that the critical exponents for the zero-field
magnetic susceptibility and the correlation length deviate from those for the
Ising lattice model on a flat plane. Furthermore, when reducing the effects of
boundary spins, the values of the critical exponents tend to those derived from
the mean field theory. These findings evidence that the underlying geometric
character is responsible for the critical properties the Ising model when the
lattice is embedded on negatively curved surfaces.Comment: 16 pages, 6 figures, to appear in J. Phys. A: Math. Ge
Manipulating the Tomonaga-Luttinger exponent by electric field modulation
We establish a theoretical framework for artificial control of the power-law
singularities in Tomonaga-Luttinger liquid states. The exponent governing the
power-law behaviors is found to increase significantly with an increase in the
amplitude of the periodic electric field modulation applied externally to the
system. This field-induced shift in the exponent indicates the tunability of
the transport properties of quasi-one-dimensional electron systems.Comment: 7 pages, 3 figure
Diffusion on a heptagonal lattice
We study the diffusion phenomena on the negatively curved surface made up of
congruent heptagons. Unlike the usual two-dimensional plane, this structure
makes the boundary increase exponentially with the distance from the center,
and hence the displacement of a classical random walker increases linearly in
time. The diffusion of a quantum particle put on the heptagonal lattice is also
studied in the framework of the tight-binding model Hamiltonian, and we again
find the linear diffusion like the classical random walk. A comparison with
diffusion on complex networks is also made.Comment: 5 pages, 6 figure
The dynamic exponent of the Ising model on negatively curved surfaces
We investigate the dynamic critical exponent of the two-dimensional Ising
model defined on a curved surface with constant negative curvature. By using
the short-time relaxation method, we find a quantitative alteration of the
dynamic exponent from the known value for the planar Ising model. This
phenomenon is attributed to the fact that the Ising lattices embedded on
negatively curved surfaces act as ones in infinite dimensions, thus yielding
the dynamic exponent deduced from mean field theory. We further demonstrate
that the static critical exponent for the correlation length exhibits the mean
field exponent, which agrees with the existing results obtained from canonical
Monte Carlo simulations.Comment: 14 pages, 3 figures. to appear in J. Stat. Mec
- âŠ