1,521 research outputs found
Vector and axial vector mesons at finite temperature
We consider the thermal correlation functions of vector and axial-vector
currents and evaluate corrections to the vector and axial-vector meson pole
terms to one loop in chiral perturbation theory. As expected, the pole
positions do not shift to leading order in temperature. But the residues
decrease with temperature
Single molecule DNA sequencing via transverse electronic transport using a graphene nanopore: A tight-binding approach
We report a tight-binding model study of two-terminal graphene nanopore based
device, for sequential determination of DNA bases. Using Greens function
approach we calculate conductance spectra, I-V response and also the changes in
local density of states (LDOS) profile as four different nucleobases inserted
one by one into the pore embedded in the zigzag graphene nanoribbon (ZGNR). We
find distinct features in LDOS profile for different nucleotides and the same
is also present in conductance and I-V response. We propose the actual working
principle of the device, by setting the bias across the pore to a fixed voltage
(this voltage gives maximum discrimination between characteristic current of
the four nucleotides) and translocating the ss-DNA through the nanopore using a
transverse electric field while recording the characteristic current of the
nucleotides. Not only the typical current output is much larger than previous
results, but the seaparation between them for different bases are also
definite. Our investigation provides high accuracy and significant amount of
distinction between different nucleotides.Comment: 6 pages, 5 figure
The large deviation principle for the Erd\H{o}s-R\'enyi random graph
What does an Erdos-Renyi graph look like when a rare event happens? This
paper answers this question when p is fixed and n tends to infinity by
establishing a large deviation principle under an appropriate topology. The
formulation and proof of the main result uses the recent development of the
theory of graph limits by Lovasz and coauthors and Szemeredi's regularity lemma
from graph theory. As a basic application of the general principle, we work out
large deviations for the number of triangles in G(n,p). Surprisingly, even this
simple example yields an interesting double phase transition.Comment: 24 pages. To appear in European J. Comb. (special issue on graph
limits
Applications of Stein's method for concentration inequalities
Stein's method for concentration inequalities was introduced to prove
concentration of measure in problems involving complex dependencies such as
random permutations and Gibbs measures. In this paper, we provide some
extensions of the theory and three applications: (1) We obtain a concentration
inequality for the magnetization in the Curie--Weiss model at critical
temperature (where it obeys a nonstandard normalization and super-Gaussian
concentration). (2) We derive exact large deviation asymptotics for the number
of triangles in the Erd\H{o}s--R\'{e}nyi random graph when .
Similar results are derived also for general subgraph counts. (3) We obtain
some interesting concentration inequalities for the Ising model on lattices
that hold at all temperatures.Comment: Published in at http://dx.doi.org/10.1214/10-AOP542 the Annals of
Probability (http://www.imstat.org/aop/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Central limit theorem for first-passage percolation time across thin cylinders
We prove that first-passage percolation times across thin cylinders of the
form obey Gaussian central limit theorems as
long as grows slower than . It is an open question as to
what is the fastest that can grow so that a Gaussian CLT still holds.
Under the natural but unproven assumption about existence of fluctuation and
transversal exponents, and strict convexity of the limiting shape in the
direction of , we prove that in dimensions 2 and 3 the CLT holds
all the way up to the height of the unrestricted geodesic. We also provide some
numerical evidence in support of the conjecture in dimension 2.Comment: Final version, accepted in Probability Theory and Related Fields. 40
pages, 7 figure
Power-law corrections to black-hole entropy via entanglement
We consider the entanglement between quantum field degrees of freedom inside
and outside the horizon as a plausible source of black-hole entropy. We examine
possible deviations of black hole entropy from area proportionality. We show
that while the area law holds when the field is in its ground state, a
correction term proportional to a fractional power of area results when the
field is in a superposition of ground and excited states. We compare our
results with the other approaches in the literature.Comment: 10 pages, 5 figures, to appear in the Proceedings of "BH2, Dynamics
and Thermodynamics of Blackholes and Naked Singularities", May 10-12 2007,
Milano, Italy; conference website: http://www.mate.polimi.it/bh2
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