30,484 research outputs found
Global well-posedness for KdV in Sobolev Spaces of negative index
The initial value problem for the Korteweg-deVries equation on the line is
shown to be globally well-posed for rough data. In particular, we show global
well-posedness for initial data in H^s({\mathbb{R}), -3/10<s.Comment: 5 pages. Electronic Journal of Differential equations (submitted
On the origin of the Fermi arc phenomena in the underdoped cuprates: signature of KT-type superconducting transition
We study the effect of thermal phase fluctuation on the electron spectral
function in a d-wave superconductor with Monte Carlo simulation.
The phase degree of freedom is modeled by a XY-type model with build-in d-wave
character. We find a ridge-like structure emerges abruptly on the underlying
Fermi surface in above the KT-transition temperature of the XY
model. Such a ridge-like structure, which shares the same characters with the
Fermi arc observed in the pseudogap phase of the underdoped cuprates, is found
to be caused by the vortex-like phase fluctuation of the XY model.Comment: 5 page
Information on the Pion Distribution Amplitude from the Pion-Photon Transition Form Factor with the Belle and BaBar Data
The pion-photon transition form factor (TFF) provides strong constraints on
the pion distribution amplitude (DA). We perform an analysis of all existing
data (CELLO, CLEO, BaBar, Belle) on the pion-photon TFF by means of light-cone
pQCD approach in which we include the next-to-leading order correction to the
valence-quark contribution and estimate the non-valence-quark contribution by a
phenomenological model based on the TFF's limiting behavior at both
and . At present, the pion DA is not definitely determined, it is
helpful to have a pion DA model that can mimic all the suggested behaviors,
especially to agree with the constraints from the pion-photon TFF in whole
measured region within a consistent way. For the purpose, we adopt the
conventional model for pion wavefunction/DA that has been constructed in our
previous paper \cite{hw1}, whose broadness is controlled by a parameter . We
fix the DA parameters by using the CELLO, CLEO, BABAR and Belle data within the
smaller region ( GeV), where all the data are consistent
with each other. And then the pion-photon TFF is extrapolated into larger
region. We observe that the BABAR favors which has the behavior close
to the Chernyak-Zhitnitsky DA, whereas the recent Belle favors which
is close to the asymptotic DA. We need more accurate data at large region
to determine the precise value of , and the definite behavior of pion DA can
be concluded finally by the consistent data in the coming future.Comment: 6 pages, 5 figures. Slightly changed and references update
How does a protein search for the specific site on DNA: the role of disorder
Proteins can locate their specific targets on DNA up to two orders of
magnitude faster than the Smoluchowski three-dimensional diffusion rate. This
happens due to non-specific adsorption of proteins to DNA and subsequent
one-dimensional sliding along DNA. We call such one-dimensional route towards
the target "antenna". We studied the role of the dispersion of nonspecific
binding energies within the antenna due to quasi random sequence of natural
DNA. Random energy profile for sliding proteins slows the searching rate for
the target. We show that this slowdown is different for the macroscopic and
mesoscopic antennas.Comment: 4 pages, 4 figure
- …