2,756 research outputs found
Low-Temperature Long-Time Simulations of Ising Ferromagnets using the Monte Carlo with Absorbing Markov Chains method
The Monte Carlo with Absorbing Markov Chains (MCAMC) method is introduced.
This method is a generalization of the rejection-free method known as the
-fold way. The MCAMC algorithm is applied to the study of the very
low-temperature properties of the lifetime of the metastable state of Ising
ferromagnets. This is done both for square-lattice and cubic-lattice
nearest-neighbor models. Comparison is made with exact low-temperature
predictions, in particular the low-temperature predictions that the metastable
lifetime is discontinuous at particular values of the field. This discontinuity
for the square lattice is not seen in finite-temperatures studies. For the
cubic lattice, it is shown that these `exact predictions' are incorrect near
the fields where there are discontinuities. The low-temperature formula must be
modified and the corrected low-temperature predictions are not discontinuous in
the energy of the nucleating droplet.Comment: Submitted to Computer Physics Communicatinos, for proceedings of the
Conference CCP2001, 4 figure
Scanning emitter lifetime imaging microscopy for spontaneous emission control
We report an experimental technique to map and exploit the local density of
optical states of arbitrary planar nano-photonic structures. The method relies
on positioning a spontaneous emitter attached to a scanning probe
deterministically and reversibly with respect to its photonic environment while
measuring its lifetime. We demonstrate the method by imaging the enhancement of
the local density of optical states around metal nanowires. By
nano-positioning, the decay rate of a pointlike source of fluorescence can be
reversibly and repeatedly changed by a factor of two by coupling it to the
guided plasmonic mode of the wire
A rejection-free Monte Carlo method for the hard-disk system
We construct a rejection-free Monte Carlo method for the hard-disk system.
Rejection-free Monte Carlo methods preserve the time-evolution behavior of the
standard Monte Carlo method, and this relationship is confirmed for our method
by observing nonequilibrium relaxation of a bond-orientational order parameter.
The rejection-free method gives a greater computational efficiency than the
standard method at high densities. The rejection free method is implemented in
a shrewd manner using optimization methods to calculate a rejection probability
and to update the system. This method should allow an efficient study of the
dynamics of two-dimensional solids at high density.Comment: 8 pages, 9 figures. This paper has been combined into the
cond-mat/0508652, and published in Phys. Rev.
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