2,965 research outputs found
Dynamic Tax Competition under Asymmetric Productivity of Public Capital
We here expand the static tax competition models in symmetric small regions, which were indicated by Zodrow and Mieszkowski (1986) and Wilson (1986), to a dynamic tax competition model in large regions, taking consideration of the regional asymmetry of productivity of public capital and the existence of capital accumulation. The aim of this paper is to verify how the taxation policy affects asymmetric equilibrium based on a simulation analysis using an overlapping generations model in two regions. It is assumed that the public capital as a public input is formed on the basis of the capital tax of local governments and the lump-sum tax of the central government. As demonstrated in related literature, the optimal capital tax rate should become zero when the lump-sum tax is imposed only on older generations, however, the optimal tax rate may become positive when it is imposed proportionally on younger and older generations. In the asymmetric equilibrium, several cooperative solutions can possibly exist which can achieve a higher welfare standard than the actualized cooperative solution either in Region1 or 2
Alpha-cluster structure and density wave in oblate nuclei
Pentagon and triangle shapes in Si-28 and C-12 are discussed in relation with
nuclear density wave. In the antisymmetrized molecular dynamics calculations,
the band in Si-28 and the band in C-12 are described by
the pentagon and triangle shapes, respectively. These negative-parity bands can
be interpreted as the parity partners of the ground bands and they
are constructed from the parity-asymmetric-intrinsic states. The pentagon and
the triangle shapes originate in 7alpha and 3alpha cluster structures,
respectively. In a mean-field picture, they are described also by the static
one-dimensional density wave at the edge of the oblate states. In analysis with
ideal alpha cluster models using Brink-Bloch cluster wave functions and that
with a simplified model, we show that the static edge density wave for the
pentagon and triangle shapes can be understood by spontaneous breaking of axial
symmetry, i.e., the instability of the oblate states with respect to the edge
density wave. The density wave is enhanced in the Z=N nuclei due to the
proton-neutron coherent density waves, while it is suppressed in Z\ne N nuclei.Comment: 23 pages, 8 figure
Chiral transition and mesonic excitations for quarks with thermal masses
We study the effect of a thermal quark mass, m_T, on the chiral phase
transition and mesonic excitations in the light quark sector at finite
temperature in a simple chirally-symmetric model. We show that while nonzero
m_T lowers the chiral condensate, the chiral transition remains of second
order. It is argued that the mesonic excitations have large decay rate at
energies below 2m_T, owing to the Landau damping of the quarks and the van Hove
singularities of the collective modes.Comment: 5 pages, 6 figures, typos correcte
Dark matter sterile neutrinos in stellar collapse: alteration of energy/lepton number transport and a mechanism for supernova explosion enhancement
We investigate matter-enhanced Mikheyev-Smirnov-Wolfenstein (MSW)
active-sterile neutrino conversion in the
channel in the collapse of the iron core of a pre-supernova star. For values of
sterile neutrino rest mass and vacuum mixing angle
(specifically, ) which include those required for viable sterile neutrino
dark matter, our one-zone in-fall phase collapse calculations show a
significant reduction in core lepton fraction. This would result in a smaller
homologous core and therefore a smaller initial shock energy, disfavoring
successful shock re-heating and the prospects for an explosion. However, these
calculations also suggest that the MSW resonance energy can exhibit a minimum
located between the center and surface of the core. In turn, this suggests a
post-core-bounce mechanism to enhance neutrino transport and neutrino
luminosities at the core surface and thereby augment shock re-heating: (1)
scattering-induced or coherent MSW conversion occurs deep in
the core, at the first MSW resonance, where energies are large ( MeV); (2) the high energy stream outward at near light speed; (3)
they deposit their energy when they encounter the second MSW resonance
just below the proto-neutron star surface.Comment: 13 pages, 9 figure
Sterile Neutrino-Enhanced Supernova Explosions
We investigate the enhancement of lepton number, energy, and entropy
transport resulting from active-sterile neutrino conversion
deep in the post-bounce supernova core followed by re-conversion
further out, near the neutrino sphere. We explicitly take
account of shock wave and neutrino heating modification of the active neutrino
forward scattering potential which governs sterile neutrino production. We find
that the luminosity at the neutrino sphere could be increased by
between and during the crucial shock re-heating epoch
if the sterile neutrino has a rest mass and vacuum mixing parameters in ranges
which include those required for viable sterile neutrino dark matter. We also
find sterile neutrino transport-enhanced entropy deposition ahead of the shock.
This `` pre-heating\rq\rq can help melt heavy nuclei and thereby reduce the
nuclear photo-dissociation burden on the shock. Both neutrino luminosity
enhancement and pre-heating could increase the likelihood of a successful core
collapse supernova explosion.Comment: 12 pages, 4 figure
Pauli-Fierz model with Kato-class potentials and exponential decays
Generalized Pauli-Fierz Hamiltonian with Kato-class potential \KPF in
nonrelativistic quantum electrodynamics is defined and studied by a path
measure. \KPF is defined as the self-adjoint generator of a strongly
continuous one-parameter symmetric semigroup and it is shown that its bound
states spatially exponentially decay pointwise and the ground state is unique.Comment: We deleted Lemma 3.1 in vol.
Hybridization-Driven Orthorhombic Lattice Instability in URu2Si2
We have measured the elastic constant (C11-C12)/2 in URu2Si2 by means of
high-frequency ultrasonic measurements in pulsed magnetic fields H || [001] up
to 61.8 T in a wide temperature range from 1.5 to 116 K. We found a reduction
of (C11-C12)/2 that appears only in the temperature and magnetic field region
in which URu2Si2 exhibits a heavy-electron state and hidden-order. This change
in (C11-C12)/2 appears to be a response of the 5f-electrons to an orthorhombic
and volume conservative strain field \epsilon_xx-\epsilon_yy with
{\Gamma}3-symmetry. This lattice instability is likely related to a
symmetry-breaking band instability that arises due to the hybridization of the
localized f electrons with the conduction electrons, and is probably linked to
the hidden-order parameter of this compound.Comment: 5 pages, 4 figure
Study on the behavior of small droplet impinging onto a hot surface
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.The effects of droplet diameter, surface roughness, and impinging velocity on the behavior of droplet impinging onto a hot surface have been studied. The surface samples used in the experiment were cylinder blocks of stainless steel having four different degrees of roughness, i.e., Ra 0.04, 0.2, 3, and 10. The diameter and impinging velocity were controlled independently by using a micro-jet dispenser. Their values were in the ranges of 300â700 ÎŒm and 1.0â4.0 m/s, respectively. The contact time was found to increase with an increase in the surface roughness and was of the order of the self-oscillation of the water droplet. The maximum spread of droplet decreased with increasing impinging velocity. The cooling curve was obtained
for the range of surface temperatures from 500 oC to 100 oC, and it was found that the cooling time decreased with an increase in the surface roughness of stainless steel. Moreover, the cooling effectiveness of each
droplet increased with an increase in the surface roughness.This study was supported by the Grant-in-Aid for Scientific Research (A) 21246036 from MEXT
No-Go Theorem for Critical Phenomena in Large-Nc QCD
We derive some rigorous results on the chiral phase transition in QCD and
QCD-like theories with a large number of colors, Nc, based on the QCD
inequalities and the large-Nc orbifold equivalence. We show that critical
phenomena and associated soft modes are forbidden in flavor-symmetric QCD at
finite temperature T and finite but not so large quark chemical potential \mu
for any nonzero quark mass. In particular, the critical point in QCD at a
finite baryon chemical potential \mu_B = Nc\mu is ruled out, if the coordinate
(T, \mu) is outside the pion condensed phase in the corresponding phase diagram
of QCD at a finite isospin chemical potential \mu_I = 2\mu.Comment: 5 pages, 1 figure; published versio
- âŠ