30,026 research outputs found
The Forced Non-Linear Schroedinger Equation with a Potential on the Half-Line
In this paper we prove that the initial-boundary value problem for the forced
non-linear Schroedinger equation with a potential on the half-line is locally
and (under stronger conditions) globally well posed, i.e. that there is a
unique solution that depends continuously on the force at the boundary and on
the initial data. We allow for a large class of unbounded potentials. Actually,
for local solutions we have no restriction on the grow at infinity of the
positive part of the potential, and for global solutions very mild assumptions
that allow, for example, for exponential grow.Comment: 23 page
and production and limits on anomalous , and couplings with D0 detector
The recent D0 results on Wgamma and Zgamma production are presented. First,
the cross section and the difference in rapidities between photons and charged
leptons for inclusive Wgamma production in egamma and mugamma final states are
discussed, then are the cross section and differential cross section as a
function of photon transverse momentum for Zgamma process. Finally, I present
the limits on anomalous WWgamma, ZZgamma and Zgammagamma couplings.Comment: 18 pages, 16 figures, review articl
On the convective instability of hot radiative accretion flows
How many fraction of gas available at the outer boundary can finally fall
onto the black hole is an important question. It determines the observational
appearance of accretion flows, and is also related with the evolution of black
hole mass and spin. Previous two-dimensional hydrodynamical simulations of hot
accretion flows find that the flow is convectively unstable because of its
inward increase of entropy. As a result, the mass accretion rate decreases
inward, i.e., only a small fraction of accretion gas can fall onto the black
hole, while the rest circulates in the convective eddies or lost in convective
outflows. Radiation is usually neglected in these simulations. In many cases,
however, radiative cooling is important. In the regime of the luminous hot
accretion flow (LHAF), radiative cooling is even stronger than the viscous
dissipation. In the one dimensional case, this implies that the inward increase
of entropy will become slower or the entropy even decreases inward in the case
of an LHAF. We therefore expect that convective instability becomes weaker or
completely disappears when radiative cooling is important. To examine the
validity of this expectation, in this paper we perform two-dimensional
hydrodynamical simulations of hot accretion flows with strong radiative
cooling. We find that compared to the case of negligible radiation, convection
only becomes slightly weaker. Even an LHAF is still strongly convectively
unstable, its radial profile of accretion rate correspondingly changes little.
We find the reason is that the entropy still increases inward in the
two-dimensional case.Comment: moderately revised, one figure added; 11 pages, 10 figures; accepted
by MNRA
1+1-dimensional p-wave superconductors from intersecting D-branes
In this work we explore 1+1 dimensional p-wave superconductors using the
probe D-brane construction. Specifically, we choose three intersecting D-brane
models: D1/D5, D2/D4 and D3/D3 systems. According to the dilaton running
behavior, we denote the former two systems as nonconformal models and the last
system as conformal. We find that all three models are qualitatively similar in
describing superconducting condensate as well as some basic features (such as
the gap formation and DC superconductivity) of superconducting conductivity.
There also exist some differences among the three models as far as the AC
conductivity is concerned. Specifically, for D3/D3 model there is no peak at
nonzero frequency for the imaginary part of the conductivity, which is present
in the nonconformal models; their asymptotic behaviors are different-for D1/D5
the real part of the AC conductivity approaches one at large frequency limit,
for D2/D4 it slowly goes to a certain nonzero constant smaller than one and for
D3/D3 it goes to zero. We find the profile of the AC conductivity for the D1/D5
system is very similar to that of higher dimensional p-wave superconductors.Comment: v2: matched with the published versio
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