1,749 research outputs found
Fast convergence to equilibrium for long-chain polymer melts using a MD/continuum hybrid method
Effective and fast convergence toward an equilibrium state for long-chain
polymer melts is realized by a hybrid method coupling molecular dynamics and
the elastic continuum. The required simulation time to achieve the equilibrium
state is reduced drastically compared with conventional equilibration methods.
The polymers move on a wide range of the energy landscape due to large-scale
fluctuation generated by the elastic continuum. A variety of chain structures
is generated in the polymer melt which results in the fast convergence to the
equilibrium state.Comment: 13 page
Faithful qubit distribution assisted by one additional qubit against collective noise
We propose a distribution scheme of polarization states of a single photon
over collective-noise channel. By adding one extra photon with a fixed
polarization, we can protect the state against collective noise via a
parity-check measurement and post-selection. While the scheme succeeds only
probabilistically, it is simpler and more flexible than the schemes utilizing
decoherence-free subspace. An application to BB84 protocol through collective
noise channel, which is robust to the Trojan horse attack, is also given.Comment: 4 pages, 3 figures; published version in Phys. Rev. Let
Geometrical complexity of conformations of ring polymers under topological constraints
One measure of geometrical complexity of a spatial curve is the number of
crossings in a planar projection of the curve.
For -noded ring polymers with a fixed knot type, we evaluate numerically
the average of the crossing number over some directions. We find that the
average crossing number under the topological constraint are less than that of
no topological constraint for large . The decrease of the geometrical
complexity is significant when the thickness of polymers is small.
The simulation with or without a topological constraint also shows that the
average crossing number and the average size of ring polymers are independent
measures of conformational complexity.Comment: 8 pages, 4figure
An Analysis of the Quantum Penny Flip Game using Geometric Algebra
We analyze the quantum penny flip game using geometric algebra and so
determine all possible unitary transformations which enable the player Q to
implement a winning strategy. Geometric algebra provides a clear visual picture
of the quantum game and its strategies, as well as providing a simple and
direct derivation of the winning transformation, which we demonstrate can be
parametrized by two angles. For comparison we derive the same general winning
strategy by conventional means using density matrices.Comment: 8 Pages, 1 Figure, accepted for publication in the Journal of
Physical Society of Japa
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