63,010 research outputs found
A cell death assay in barley and wheat protoplasts for identification and validation of matching pathogen AVR effector and plant NLR immune receptors
Zero sound in a two-dimensional dipolar Fermi gas
We study zero sound in a weakly interacting 2D gas of single-component
fermionic dipoles (polar molecules or atoms with a large magnetic moment)
tilted with respect to the plane of their translational motion. It is shown
that the propagation of zero sound is provided by both mean field and many-body
(beyond mean field) effects, and the anisotropy of the sound velocity is the
same as the one of the Fermi velocity. The damping of zero sound modes can be
much slower than that of quasiparticle excitations of the same energy. One thus
has wide possibilities for the observation of zero sound modes in experiments
with 2D fermionic dipoles, although the zero sound peak in the structure
function is very close to the particle-hole continuum.Comment: 15 pages, 2 figure
Computing the Girth of a Planar Graph in Linear Time
The girth of a graph is the minimum weight of all simple cycles of the graph.
We study the problem of determining the girth of an n-node unweighted
undirected planar graph. The first non-trivial algorithm for the problem, given
by Djidjev, runs in O(n^{5/4} log n) time. Chalermsook, Fakcharoenphol, and
Nanongkai reduced the running time to O(n log^2 n). Weimann and Yuster further
reduced the running time to O(n log n). In this paper, we solve the problem in
O(n) time.Comment: 20 pages, 7 figures, accepted to SIAM Journal on Computin
Lifshitz transitions in a heavy-Fermion liquid driven by short-range antiferromagnetic correlations in the two-dimensional Kondo lattice model
The heavy-Fermion liquid with short-range antiferromagnetic correlations is
carefully considered in the two-dimensional Kondo-Heisenberg lattice model. As
the ratio of the local Heisenberg superexchange to the Kondo coupling
increases, Lifshitz transitions are anticipated, where the topology of
the Fermi surface (FS) of the heavy quasiparticles changes from a hole-like
circle to four kidney-like pockets centered around . In-between
these two limiting cases, a first-order quantum phase transition is identified
at where a small circle begins to emerge within the large
deformed circle. When , the two deformed circles intersect
each other and then decompose into four kidney-like Fermi pockets via a
second-order quantum phase transition. As increases further, the
Fermi pockets are shifted along the direction () to (),
and the resulting FS is consistent with the FS obtained recently using the
quantum Monte Carlo cluster approach to the Kondo lattice system in the
presence of the antiferrmagnetic order.Comment: 4 pages, 5 figure
More is Less: Perfectly Secure Oblivious Algorithms in the Multi-Server Setting
The problem of Oblivious RAM (ORAM) has traditionally been studied in a
single-server setting, but more recently the multi-server setting has also been
considered. Yet it is still unclear whether the multi-server setting has any
inherent advantages, e.g., whether the multi-server setting can be used to
achieve stronger security goals or provably better efficiency than is possible
in the single-server case.
In this work, we construct a perfectly secure 3-server ORAM scheme that
outperforms the best known single-server scheme by a logarithmic factor. In the
process, we also show, for the first time, that there exist specific algorithms
for which multiple servers can overcome known lower bounds in the single-server
setting.Comment: 36 pages, Accepted in Asiacrypt 201
An accretion model for the growth of the central black hole associated with ionization instability in quasars
A possible accretion model associated with the ionization instability of
quasar disks is proposed to address the growth of the central black hole
harbored in the host galaxy.The mass ratio between black hole and its host
galactic bulge is a nature consequence of our model.Comment: submitted to ApJ, 15 page
Correlation-hole induced paired quantum Hall states in lowest Landau level
A theory is developed for the paired even-denominator fractional quantum Hall
states in the lowest Landau level. We show that electrons bind to quantized
vortices to form composite fermions, interacting through an exact instantaneous
interaction that favors chiral p-wave pairing. Two canonically dual pairing gap
functions are related by the bosonic Laughlin wavefunction (Jastraw factor) due
to the correlation holes. We find that the ground state is the Moore-Read
pfaffian in the long wavelength limit for weak Coulomb interactions, a new
pfaffian of an oscillatory pairing function for intermediate interactions, and
a Read-Rezayi composite Fermi liquid beyond a critical interaction strength.
Our findings are consistent with recent experimental observations of the 1/2
and 1/4 fractional quantum Hall effects in asymmetric wide quantum wells.Comment: 4 pages, 2 figures; published versio
Metal-insulator transition in half-filling two-orbital Hubbard model on triangular lattice
We have investigated the half-filling two-orbital Hubbard model on a
triangular lattice by means of the dynamical mean-field theory (DMFT). The
densities of states and optical conductivity clearly show the occurence of
metal-insulating transition (MIT) at U, U=18.2, 16.8, 6.12 and 5.85
for J=0, 0.01U, U/4 and U/3, respectively. The distinct continuities of double
occupation of electrons, local square moments and local susceptibility of the
charge, the spin and the orbital at J > 0 suggest that the MIT is the
first-order; however at J=0, the MIT is the second-order in the half-filling
two-orbital Hubbard model on triangular lattices. We attribute the first-order
nature of the MIT to the low symmetry of the systems with finite Hund's
coupling J.Comment: 5 figures,13 pages, published versio
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