Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The coherent scattering function in the reptation model: analysis beyond
  asymptotic limits   We calculate the coherent dynamical scattering function S_c(q,t;N) of a
flexible chain of length N, diffusing through an ordered background of
topological obstacles. As an instructive generalization, we also calculate the
scattering function S_c(q,t;M,N) for the central piece of length M < N of the
chain. Using the full reptation model, we treat global creep, tube length
fluctuations, and internal relaxation within a consistent and unified approach.
Our theory concentrates on the universal aspects of reptational motion, and our
results in all details show excellent agreement with our simulations of the
Evans-Edwards model, provided we allow for a phenomenological prefactor which
accounts for non-universal effects of the micro-structure of the Monte Carlo
chain, present for short times. Previous approaches to the coherent structure
function can be analyzed as special limits of our theory. First, the effects of
internal relaxation can be isolated by studying the limit $N \to \infty$, M
fixed. The results do not support the model of a `Rouse chain in a tube'. We
trace this back to the non-equilibrium initial conditions of the latter model.
Second, in the limit of long chains $(M = N \to \infty)$ and times large
compared to the internal relaxation time $(t/N^2 \to \infty)$, our theory
reproduces the results of the primitive chain model. This limiting form applies
only to extremely long chains, and for chain lengths accessible in practice,
effects of, e.g., tube length fluctuations are not negligible.

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The categories of this paper are: funct-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: comp-gas
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The categories of this paper are: astro-ph
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The categories of this paper are: q-alg