17,991 research outputs found
Generalized Metropolis dynamics with a generalized master equation: An approach for time-independent and time-dependent Monte Carlo simulations of generalized spin systems
The extension of Boltzmann-Gibbs thermostatistics, proposed by Tsallis,
introduces an additional parameter to the inverse temperature .
Here, we show that a previously introduced generalized Metropolis dynamics to
evolve spin models is not local and does not obey the detailed energy balance.
In this dynamics, locality is only retrieved for , which corresponds to
the standard Metropolis algorithm. Non-locality implies in very time consuming
computer calculations, since the energy of the whole system must be
reevaluated, when a single spin is flipped. To circumvent this costly
calculation, we propose a generalized master equation, which gives rise to a
local generalized Metropolis dynamics that obeys the detailed energy balance.
To compare the different critical values obtained with other generalized
dynamics, we perform Monte Carlo simulations in equilibrium for Ising model. By
using the short time non-equilibrium numerical simulations, we also calculate
for this model: the critical temperature, the static and dynamical critical
exponents as function of . Even for , we show that suitable time
evolving power laws can be found for each initial condition. Our numerical
experiments corroborate the literature results, when we use non-local dynamics,
showing that short time parameter determination works also in this case.
However, the dynamics governed by the new master equation leads to different
results for critical temperatures and also the critical exponents affecting
universality classes. We further propose a simple algorithm to optimize
modeling the time evolution with a power law considering in a log-log plot two
successive refinements.Comment: 10 pages, 5 figures and 5 table
A novel and precise time domain description of MOSFET low frequency noise due to random telegraph signals
Nowadays, random telegraph signals play an important role in integrated
circuit performance variability, leading for instance to failures in memory
circuits. This problem is related to the successive captures and emissions of
electrons at the many traps stochastically distributed at the silicon-oxide
(Si-SiO2) interface of MOS transistors. In this paper we propose a novel
analytical and numerical approach to statistically describe the fluctuations of
current due to random telegraph signal in time domain. Our results include two
distinct situations: when the density of interface trap density is uniform in
energy, and when it is an u-shape curve as prescribed in literature, here
described as simple quadratic function. We establish formulas for relative
error as function of the parameters related to capture and emission
probabilities. For a complete analysis experimental u-shape curves are used and
compared with the theoretical aproach
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