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R D Sedgewick

Publications and source records attributed to R D Sedgewick.

3 recordsLinked to original sources

Accelerated multiboson algorithm for Coulomb gases with dynamical dielectric effects.

A recent reformulation [Phys. Rev. E 73, 016705 (2006)] of the problem of Coulomb gases in the presence of a dynamical dielectric medium showed that finite-temperature simulations of such systems can be accomplished on the basis of completely local Hamiltonians on a spatial lattice by including additional bosonic fields. For large systems, the Monte Carlo algorithm proposed in the above-cited work becomes inefficient due to a low acceptance rate for particle moves in a fixed background multiboson field. We show here how this problem can be circumvented by use of a coupled particle-multiboson update procedure that improves acceptance rates on large lattices by orders of magnitude. The method is tested on a one-component plasma with neutral dielectric particles for a variety of system sizes.

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Local simulation algorithms for Coulomb gases with dynamical dielectric effects.

We discuss the application of the local lattice technique of Maggs and Rossetto [Phys. Rev. Lett. 88, 196402 (2002)] to problems that involve the motion of objects with different dielectric constants than the background. In these systems, the simulation method produces a spurious interaction force which causes the particles to move in an unphysical manner. We show that this term can be removed using a variant of a method known from high-energy physics simulations, the multiboson method, and demonstrate the effectiveness of this corrective method on a system of neutral particles. We then apply our method to a one-component plasma to show the effect of the spurious interaction term on a charged system.

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Improved local lattice approach for Coulombic simulations.

An improved approach to the simulation of strongly fluctuating Coulomb gases, based on a local lattice technique introduced by Maggs and Rossetto [A.C. Maggs and V. Rossetto, Phys. Rev. Lett. 88, 196402 (2002)], is described and then tested in a problem of biophysical interest. The low acceptance rates for charged particle moves in regimes of physical interest are increased to a serviceable level by use of a coupled particle-field update procedure in the new method. Sensitivity of the results to lattice discretization effects is also studied using asymmetric lattices.

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