Biomedical subjects

Chenggang Zhou

Publications and source records attributed to Chenggang Zhou.

3 recordsLinked to original sources

PubMed2006

Wang-Landau algorithm for continuous models and joint density of states.

We present a modified Wang-Landau algorithm for models with continuous degrees of freedom. We demonstrate this algorithm with the calculation of the joint density of states of ferromagnet Heisenberg models and a model polymer chain. The joint density of states contains more information than the density of states of a single variable-energy, but is also much more time consuming to calculate. We present strategies to significantly speed up this calculation for large systems over a large range of energy and order parameter.

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PubMed2005

Understanding and improving the Wang-Landau algorithm.

We present a mathematical analysis of the Wang-Landau algorithm, prove its convergence, and identify sources of errors and strategies for optimization. In particular, we found the histogram increases uniformly with small fluctuations after a stage of initial accumulation, and the statistical error is found to scale as square root of (ln f) with the modification factor f . This has implications for strategies for obtaining fast convergence.

Journal Article↗

PubMed2004

Laterally modulated 2D electron system in the extreme quantum limit.

We report on magnetotransport of a two-dimensional electron system (2DES), located 32 nm below the surface, with a surface superlattice gate structure of periodicity 39 nm imposing a periodic modulation of its potential. For low Landau level fillings nu, the diagonal resistivity displays a rich pattern of fluctuations, even though the disorder dominates over the periodic modulation. Theoretical arguments based on the combined effects of the long-wavelength, strong disorder and the short-wavelength, weak periodic modulation present in the 2DES qualitatively explain the data.

Journal Article↗