1,819 research outputs found
The Industry Origins of Japanese Economic Growth
This paper presents new data on the sources of growth for the Japanese economy over the period 1960- 2000. The principal innovation is the incorporation of detailed information for individual industries, including those involved in the production of computers, communications equipment, and electronic components as information technology equipment. We show that economic growth is dominated by investments and productivity growth in information technology, both for individual industries and the economy as a whole. We also show that the revival of total factor productivity growth accounts for the modest resurgence of the Japanese economy since 1995.
Aging of the Zero-Field-Cooled Magnetization in Ising Spin Glasses: Experiment and Numerical Simulation
A new protocol of the zero-field-cooled (ZFC) magnetization process is
studied experimentally on an Ising spin-glass (SG)
FeMnTiO and numerically on the Edwards-Anderson Ising SG
model. Although the time scales differ very much between the experiment and the
simulation, the behavior of the ZFC magnetization observed in the two systems
can be interpreted by means of a common scaling expression based on the droplet
picture. The results strongly suggest that the SG coherence length, or the mean
size of droplet excitations, involved even in the experimental ZFC process, is
about a hundred lattice distances or less.Comment: 4 pages, 5 fugure
On the direct indecomposability of infinite irreducible Coxeter groups and the Isomorphism Problem of Coxeter groups
In this paper we prove, without the finite rank assumption, that any
irreducible Coxeter group of infinite order is directly indecomposable as an
abstract group. The key ingredient of the proof is that we can determine, for
an irreducible Coxeter group, the centralizers of the normal subgroups that are
generated by involutions. As a consequence, we show that the problem of
deciding whether two general Coxeter groups are isomorphic, as abstract groups,
is reduced to the case of irreducible Coxeter groups, without assuming the
finiteness of the number of the irreducible components or their ranks. We also
give a description of the automorphism group of a general Coxeter group in
terms of those of its irreducible components.Comment: 30 page
A Higgs Quadruplet for Type III Seesaw and Implications for and Conversion
In Type III seesaw model the heavy neutrinos are contained in leptonic
triplet representations. The Yukawa couplings of the triplet fermion and the
left-handed neutrinos with the doublet Higgs field produce the Dirac mass
terms. Together with the Majorana masses for the leptonic triplets, the light
neutrinos obtain non-zero seesaw masses. We point out that it is also possible
to have a quadruplet Higgs field to produce the Dirac mass terms to facilitate
the seesaw mechanism. The vacuum expectation value of the quadruplet Higgs is
constrained to be small by electroweak precision data. Therefore the Yukawa
couplings of a quadruplet can be much larger than those for a doublet. We also
find that unlike the usual Type III seesaw model where at least two copies of
leptonic triplets are needed, with both doublet and quadruplet Higgs
representations, just one leptonic triplet is possible to have a
phenomenologically acceptable model because light neutrino masses can receive
sizable contributions at both tree and one loop levels. Large Yukawa couplings
of the quadruplet can induce observable effects for lepton flavor violating
processes and conversion. Implications of the
recent limit from MEG and also limit on conversion
on Au are also given. Some interesting collider signatures for the doubly
charged Higgs boson in the quadruplet are discussed.Comment: Latex 11 pages, 1 figure. A few references adde
Observation of Antinormally Ordered Hanbury-Brown--Twiss Correlations
We have measured antinormally ordered Hanbury-Brown--Twiss correlations for
coherent states of electromagnetic field by using stimulated parametric
down-conversion process. Photons were detected by stimulated emission, rather
than by absorption, so that the detection responded not only to actual photons
but also to zero-point fluctuations via spontaneous emission. The observed
correlations were distinct from normally ordered ones as they showed excess
positive correlations, i.e., photon bunching effects, which arose from the
thermal nature of zero-point fluctuations.Comment: 5 pages, 3 figures, to appear in Physical Review Letter
Rapid Thermalization by Baryon Injection in Gauge/Gravity Duality
Using the AdS/CFT correspondence for strongly coupled gauge theories, we
calculate thermalization of mesons caused by a time-dependent change of a
baryon number chemical potential. On the gravity side, the thermalization
corresponds to a horizon formation on the probe flavor brane in the AdS throat.
Since heavy ion collisions are locally approximated by a sudden change of the
baryon number chemical potential, we discuss implication of our results to RHIC
and LHC experiments, to find a rough estimate of rather rapid thermalization
time-scale t_{th} < 1 [fm/c]. We also discuss universality of our analysis
against varying gauge theories.Comment: 9 pages, 7 figures. v2: minor clarifications, version to appear in
PR
Topologically nontrivial magnonic solitons
The intrinsic non-linearities of the spin dynamics in condensed matter
systems give rise to a rich phenomenology that can be strongly affected by
topology. Here we study formation of magnonic solitons in the topologically
nontrivial bandgap of a spin lattice realization of the Haldane model, in both
static and dynamic (Floquet) regimes. We consider nonlinearities caused by
magnetic crystalline anisotropy and magnon-magnon interactions. We find soliton
formation power thresholds as a function of anisotropy coefficient and
interaction strength. We predict different classes of topological solitons for
the same topological class of the underlying lattice and explain it in terms of
a transition from a topologically nontrivial mass to a trivial one. Our
findings imply that a soliton can phase-separate, containing boundaries between
topologically trivial and non-trivial phases, which is associated with a
vanishing spin wave gap
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