14,982 research outputs found
Boundary Condition of Polyelectrolyte Adsorption
The modification of the boundary condition for polyelectrolyte adsorption on
charged surface with short-ranged interaction is investigated under two
regimes. For weakly charged Gaussian polymer in which the short-ranged
attraction dominates, the boundary condition is the same as that of the neutral
polymer adsorption. For highly charged polymer (compressed state) in which the
electrostatic interaction dominates, the linear relationship (electrostatic
boundary condition) between the surface monomer density and the surface charge
density needs to be modified.Comment: 4 page
Anatomy of Zero-norm States in String Theory
We calculate and identify the counterparts of zero-norm states in the old
covariant first quantised (OCFQ) spectrum of open bosonic string in two other
quantization schemes of string theory, namely the light-cone DDF zero-norm
states and the off-shell BRST zero-norm states (with ghost) in the Witten
string field theory (WSFT). In particular, special attention is paid to the
inter-particle zero-norm states in all quantization schemes. For the case of
the off-shell BRST zero-norm states, we impose the no ghost conditions and
recover exactly two types of on-shell zero-norm states in the OCFQ string
spectrum for the first few low-lying mass levels. We then show that off-shell
gauge transformations of WSFT are identical to the on-shell stringy gauge
symmetries generated by two types of zero-norm states in the generalized
massive sigma-model approach of string theory. The high energy limit of these
stringy gauge symmetries was recently used to calculate the proportionality
constants, conjectured by Gross, among high energy scattering amplitudes of
different string states. Based on these zero-norm state calculations, we have
thus related gauge symmetry of WSFT to the high-energy stringy symmetry of
Gross.Comment: 30 page
Grain-boundary grooving and agglomeration of alloy thin films with a slow-diffusing species
We present a general phase-field model for grain-boundary grooving and
agglomeration of polycrystalline alloy thin films. In particular, we study the
effects of slow-diffusing species on grooving rate. As the groove grows, the
slow species becomes concentrated near the groove tip so that further grooving
is limited by the rate at which it diffuses away from the tip. At early times
the dominant diffusion path is along the boundary, while at late times it is
parallel to the substrate. This change in path strongly affects the
time-dependence of grain boundary grooving and increases the time to
agglomeration. The present model provides a tool for agglomeration-resistant
thin film alloy design. keywords: phase-field, thermal grooving, diffusion,
kinetics, metal silicidesComment: 4 pages, 6 figure
Unusual Coupling Between Field-induced Spin Fluctuations and Spin Density Wave in Intermetallic CeAg2Ge2
We report on the experimental evidences for an unusual coupling between the
magnetic field- induced fluctuations of correlated Ce-ions coinciding with the
discontinuous movement of the underlying spin density wave in the intermetallic
rare earth compound CeAg2Ge2. The measurements performed using neutron
scattering and magnetic Gruneisen ratio methods suggest that the coupling
onsets at H= 2.7 T, T < 3.8 K and persists to the lowest measurement
temperature T ~ 0.05 K. These measurements suggest a new mechanism behind the
spin fluctuations which can affect the intrinsic properties of the system.Comment: 4 pages, 4 figures, Strongly correlated electrons syste
Exactness of the Original Grover Search Algorithm
It is well-known that when searching one out of four, the original Grover's
search algorithm is exact; that is, it succeeds with certainty. It is natural
to ask the inverse question: If we are not searching one out of four, is
Grover's algorithm definitely not exact? In this article we give a complete
answer to this question through some rationality results of trigonometric
functions.Comment: 8 pages, 2 figure
Doping Dependence of Spin Dynamics in Electron-Doped Ba(Fe1-xCox)2As2
The spin dynamics in single crystal, electron-doped Ba(Fe1-xCox)2As2 has been
investigated by inelastic neutron scattering over the full range from undoped
to the overdoped regime. We observe damped magnetic fluctuations in the normal
state of the optimally doped compound (x=0.06) that share a remarkable
similarity with those in the paramagnetic state of the parent compound (x=0).
In the overdoped superconducting compound (x=0.14), magnetic excitations show a
gap-like behavior, possibly related to a topological change in the hole Fermi
surface (Lifshitz transition), while the imaginary part of the spin
susceptibility prominently resembles that of the overdoped cuprates. For the
heavily overdoped, non-superconducting compound (x=0.24) the magnetic
scattering disappears, which could be attributed to the absence of a hole
Fermi-surface pocket observed by photoemission.Comment: 6 pages, 5 figures, published versio
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