6,784 research outputs found
A model of an optical biosensor detecting environment
Heller et. Al. (Science 311, 508 (2006)) demonstrated the first DNA-CN
optical sensor by wrapping a piece of double-stranded DNA around the surface of
single-walled carbon nanotubes (CN). This new type of optical device can be
placed inside living cells and detect trace amounts of harmful contaminants by
means of near infrared light. Using a simple exciton theory in nanostructures
and the phenomena of B-Z structural phase transition of DNA, we investigate the
working principle of this new class of optical biosensor from DNA by using the
nanostructure surface as a sensor to detect the property change of DNA as it
responds to the presence of target ions. We also propose some new design models
by replacing carbon nanotubes with graphene ribbon semiconductors.Comment: 4 pages, 4 figures, Accepte
The Yoneda algebra of a graded Ore extension
Let A be a connected-graded algebra with trivial module k, and let B be a
graded Ore extension of A. We relate the structure of the Yoneda algebra E(A)
:= Ext_A(k,k) to E(B). Cassidy and Shelton have shown that when A satisfies
their K_2 property, B will also be K_2. We prove the converse of this result.Comment: 9 page
Linear response within the projection-based renormalization method: Many-body corrections beyond the random phase approximation
The explicit evaluation of linear response coefficients for interacting
many-particle systems still poses a considerable challenge to theoreticians. In
this work we use a novel many-particle renormalization technique, the so-called
projector-based renormalization method, to show how such coefficients can
systematically be evaluated. To demonstrate the prospects and power of our
approach we consider the dynamical wave-vector dependent spin susceptibility of
the two-dimensional Hubbard model and also determine the subsequent magnetic
phase diagram close to half-filling. We show that the superior treatment of
(Coulomb) correlation and fluctuation effects within the projector-based
renormalization method significantly improves the standard random phase
approximation results.Comment: 17 pages, 7 figures, revised versio
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