904 research outputs found
Pseudospectral methods for atoms in strong magnetic fields
We present a new pseudospectral algorithm for the calculation of the
structure of atoms in strong magnetic fields. We have verified this technique
for one, two and three-electron atoms in zero magnetic fields against
laboratory results and find typically better than one-percent accuracy. We
further verify this technique against the state-of-the-art calculations of
hydrogen, helium and lithium in strong magnetic fields (up to about T) and find a similar level of agreement. The key enabling advantages
of the algorithm are its simplicity (about 130 lines of commented code) and its
speed (about times faster than finite-element methods to achieve
similar accuracy).Comment: 10 pages, version accepted to MNRA
Diffusion-limited loop formation of semiflexible polymers: Kramers theory and the intertwined time scales of chain relaxation and closing
We show that Kramers rate theory gives a straightforward, accurate estimate
of the closing time of a semiflexible polymer that is valid in cases
of physical interest. The calculation also reveals how the time scales of chain
relaxation and closing are intertwined, illuminating an apparent conflict
between two ways of calculating in the flexible limit.Comment: Europhys. Lett., 2003 (in press). 8 pages, 3 figures. See also,
physics/0101087 for physicist's approach to and the importance of
semiflexible polymer looping, in DNA replicatio
Probing protein-protein interactions by dynamic force correlated spectroscopy (FCS)
We develop a formalism for single molecule dynamic force spectroscopy to map
the energy landscape of protein-protein complex (). The joint
distribution of unbinding lifetimes and
measurable in a compression-tension cycle, which accounts for the internal
relaxation dynamics of the proteins under tension, shows that the histogram of
is not Poissonian. The theory is applied to the forced unbinding of
protein , modeled as a wormlike chain, from . We propose a new
class of experiments which can resolve the effect of internal protein dynamics
on the unbinding lifetimes.Comment: 12 pages, 3 figures, accepted to Phys. Rev. Let
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