14,864 research outputs found
Entry cost, financial friction, and cross-country differences in income and TFP
This paper develops a model to assess the quantitative effect of entry cost and financial friction on cross-country income and total factor productivity (TFP) differences. The main focus is on the interaction between entry cost and financial friction. The model is calibrated to match establishment-level statistics for the U.S. economy assuming a perfect financial market. The quantitative analysis shows that entry costs and financial frictions together can generate a factor ten of the differences in income per capita and a factor five of the differences in TFP, and a large part of the differences are accounted for by the interaction between entry cost and financial friction. The main mechanism is that financial friction amplifies the effect of entry cost by boosting the effective entry cost.
Entry barriers, competition, and technology adoption
There are large differences in income per capita across countries. Growth accounting finds that a large part of the differences comes from the differences in total factor productivity (TFP). This paper explores whether barrier to entry is an important factor for the cross-country differences in TFP. The paper develops a new model to link entry barriers and technology adoption. In the model, higher barriers to entry effectively reduce entry threat, and lower entry threat leads to adoption of less productive technologies. The paper demonstrates that technology adopted in the economy with entry threats is at least as good as the technology adopted in the economy without entry threats. Moreover, the paper presents numerical simulations that suggest entry barriers could be a quantitatively important reason for cross-country differences in TFP and are more harmful to productivity in the countries with monopolists facing inelastic demand.Productivity
Numerical study of ergodicity for the overdamped Generalized Langevin Equation with fractional noise
The Generalized Langevin Equation, in history, arises as a natural fix for
the rather traditional Langevin equation when the random force is no longer
memoryless. It has been proved that with fractional Gaussian noise (fGn) mostly
considered by biologists, the overdamped Generalized Langevin equation
satisfying fluctuation-dissipation theorem can be written as a fractional
stochastic differential equation (FSDE). While the ergodicity is clear for
linear forces, it remains less transparent for nonlinear forces. In this work,
we present both a direct and a fast algorithm respectively to this FSDE model.
The strong orders of convergence are proved for both schemes, where the role of
the memory effects can be clearly observed. We verify the convergence theorems
using linear forces, and then present the ergodicity study of the double well
potentials in both 1D and 2D setups
Study of the heavy CP-even Higgs with mass 125 GeV in two-Higgs-doublet models at the LHC and ILC
We assume that the 125 GeV Higgs discovered at the LHC is the heavy CP-even
Higgs of the two-Higgs-doublet models, and examine the parameter space in the
Type-I, Type-II, Lepton-specific and Flipped models allowed by the latest Higgs
signal data, the relevant experimental and theoretical constraints. Further, we
show the projected limits on , , and
couplings from the future measurements of the 125 GeV Higgs at the LHC
and ILC, including the LHC with integrated luminosity of 300 fb (LHC-300
fb) and 3000 fb (LHC-3000 fb) as well as the ILC at
GeV (ILC-250 GeV), GeV (ILC-500 GeV) and
GeV (ILC-1000 GeV). Assuming that the future Higgs signal data
have no deviation from the SM expectation, the LHC-300 fb, LHC-3000
fb and ILC-1000 GeV can exclude the wrong-sign Yukawa coupling regions
of the Type-II, Flipped and Lepton-specific models at the level,
respectively. The future experiments at the LHC and ILC will constrain the
Higgs couplings to be very close to SM values, especially for the
coupling.Comment: 22 pages, 3 tables, 6 figures. Version accepted for publication in
JHE
A simplified 2HDM with a scalar dark matter and the galactic center gamma-ray excess
Due to the strong constrain from the LUX experiment, the scalar portal dark
matter can not generally explain a gamma-ray excess in the galactic center by
the annihilation of dark matter into . With the motivation of
eliminating the tension, we add a scalar dark matter to the aligned
two-Higgs-doublet model, and focus on a simplified scenario, which has two main
characteristics: (i) The heavy CP-even Higgs is the discovered 125 GeV Higgs
boson, which has the same couplings to the gauge bosons and fermions as the SM
Higgs. (ii) Only the light CP-even Higgs mediates the dark matter interactions
with SM particles, which has no couplings to and , but the independent
couplings to the up-type quarks, down-type quarks and charged leptons. We find
that the tension between and the constraint from
LUX induced by the scalar portal dark matter can go away for the
isospin-violating dark matter-nucleon coupling with , and
the constraints from the Higgs search experiments and the relic density of
Planck are also satisfied.Comment: 12 pages, 3 figures, 1 table; reference adde
Status of the aligned two-Higgs-doublet model confronted with the Higgs data
Imposing the theoretical constraints from vacuum stability, unitarity and
perturbativity as well as the experimental constraints from the electroweak
precision data, flavor observables and the non-observation of additional Higgs
at collider, we study the implications of available Higgs signals on a
two-Higgs-doublet model with the alignment of the down-type quarks and charged
lepton Yukawa coupling matrices. Compared to the four traditional types of
two-Higgs-doublet models, the model has two additional mixing angles
and in the down-type quark and charged lepton Yukawa interactions.
We find that the mixing angle can loose the constraints on
, and sizably. The model can
provide the marginally better fit to available Higgs signals data than SM,
which requires the Higgs couplings with gauge bosons, and
to be properly suppressed, and favors (1 <\theta_d< 2, 0.5 <\theta_l< 2.2) for
125.5 GeV and (0.5 <\theta_d< 2, 0.5 <\theta_l< 2.2) for 125.5
GeV. However, these Higgs couplings are allowed to have sizable deviations from
SM for ( 125.5 GeV, 125.5 128 GeV) and (125 GeV 125.5 GeV, 125.5 GeV).Comment: 21 pages, 9 figures and 3 tables. Final version appeared in JHE
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