180 research outputs found
Cold and Warm Denaturation of Proteins
We introduce a simplified protein model where the water degrees of freedom
appear explicitly (although in an extremely simplified fashion). Using this
model we are able to recover both the warm and the cold protein denaturation
within a single framework, while addressing important issues about the
structure of model proteins
Spectral coarse-graining of complex networks
Reducing the complexity of large systems described as complex networks is key
to understand them and a crucial issue is to know which properties of the
initial system are preserved in the reduced one. Here we use random walks to
design a coarse-graining scheme for complex networks. By construction the
coarse-graining preserves the slow modes of the walk, while reducing
significantly the size and the complexity of the network. In this sense our
coarse-graining allows to approximate large networks by smaller ones, keeping
most of their relevant spectral properties.Comment: 4 pages, 2 figure
Putting Proteins back into Water
We introduce a simplified protein model where the solvent (water) degrees of
freedom appear explicitly (although in an extremely simplified fashion). Using
this model we are able to recover the thermodynamic phenomenology of proteins
over a wide range of temperatures. In particular we describe both the warm and
the {\it cold} protein denaturation within a single framework, while addressing
important issues about the structure of model proteins.Comment: 4 Pages, 4 Figures. To appear on PR
Berry Phase and Ground State Symmetry in H x h Dynamical Jahn-Teller Systems
Due to the ubiquitous presence of a Berry phase, in most cases of dynamical
Jahn-Teller systems the symmetry of the vibronic ground state is the same as
that of the original degenerate electronic state. As a single exception, the
linear H x h icosahedral model, relevant to the physics of C60 cations, is
determined by an additional free parameter, which can be continuously tuned to
eliminate the Berry phase from the low-energy closed paths: accordingly, the
ground state changes to a totally-symmetric nondegenerate state.Comment: RevTex, 4 pages, 3 figure
Directed Polymers on a Factorized Disorder Landscape
We study the Directed Polymer model subject to a particular form of disorder,
, recently proposed in biological applications.
We find that two new universality classes arise, depending on the the lattice
geometry. Using an intermediate model linking the two different orientations
continuously, we find that there is a phase transition separating two distinct
scaling phases. For both phases we get a reasonable understanding of the nature
and values of the exponents, corroborated with numerical results.Comment: 4 pages, 4 .eps figure
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