113,623 research outputs found
Polymer Translocation througha Pore in a Membrane
We construct a new statistical physical model of polymer translocation
through a pore in a membrane treated as the diffusion process across a free
energy barrier. We determine the translocation time in terms of chain
flexibility yielding an entropic barrier, as well as in terms of the driving
mechanisms such as transmembrane chemical potential difference and Brownian
ratchets. It turns out that, while the chemical potential differences induce
pronounced effects on translocation due to the long-chain nature of the
polymer, the ratchets suppress this effect and chain flexibility.Comment: 4 pages, 5 figures, published in Phys. Rev. Lett. 77, 783(1996
Eta invariants with spectral boundary conditions
We study the asymptotics of the heat trace \Tr\{fPe^{-tP^2}\} where is
an operator of Dirac type, where is an auxiliary smooth smearing function
which is used to localize the problem, and where we impose spectral boundary
conditions. Using functorial techniques and special case calculations, the
boundary part of the leading coefficients in the asymptotic expansion is found.Comment: 19 pages, LaTeX, extended Introductio
Universal curvature identities
We study scalar and symmetric 2-form valued universal curvature identities.
We use this to establish the Gauss-Bonnet theorem using heat equation methods,
to give a new proof of a result of Kuz'mina and Labbi concerning the
Euler-Lagrange equations of the Gauss-Bonnet integral, and to give a new
derivation of the Euh-Park-Sekigawa identity.Comment: 11 page
Muon anomalous magnetic moment from effective supersymmetry
We present a detailed analysis on the possible maximal value of the muon
(g-2) (= 2 a_mu) within the context of effective SUSY models with R parity
conservation. First of all, the mixing among the second and the third family
sleptons can contribute at one loop level to the a_mu(SUSY) and tau -> mu gamma
simultaneously. One finds that the a_mu(SUSY) can be as large as (10-20)*10^-10
for any tan beta, imposing the upper limit on the tau -> mu gamma branching
ratio. Furthermore, the two-loop Barr-Zee type contributions to a_mu(SUSY) can
be significant for large tan beta, if a stop is light and mu and A_t are large
enough (O(1) TeV). In this case, it is possible to have a_mu(SUSY) upto
O(10)*10^-10 without conflicting with tau -> l gamma. We conclude that the
possible maximal value for a_mu(SUSY) is about 20*10^-10 for any tan beta.
Therefore the BNL experiment on the muon a_mu can exclude the effective SUSY
models only if the measured deviation is larger than \sim 30*10^-10.Comment: 10 pages, 3 figure
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