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Universal fluctuations in phonon transmission and other features of phonon-transmission histograms are investigated by performing numerical simulations of coherent-phonon transport in isotope-disordered carbon nanotubes. Interestingly, the phonon-transmission fluctuation in the diffusive regime is universal, irrespective of the average phonon transmission, the tube chirality, and the concentrations, and masses of isotopes. We also find that the histogram, which has a Gaussian distribution in the diffusive regime, has a log-normal distribution in the localization regime.

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The microscopic structure of surface water adsorbed on graphene is elucidated theoretically by classical molecular dynamics simulation. At a low temperature (100 K), the main polygon consisting of hydrogen bonds in single-layered water on graphene is tetragonal, whereas the dominant polygons in double-layered water are tetragonal, pentagonal, and hexagonal. On the other hand, at room temperature, the tetragonal, pentagonal, and hexagonal water clusters are the main structures in both single-and double-layered water.

The transient current dynamics of a quantum capacitor consisting of a quantum dot connected to a single electrode has been theoretically investigated by the nonequilibrium Green’s function method. We have clarified the influence of dot-electrode coupling strength on the transient current behavior of the quantum capacitor. Our simulation reproduces very well the behaviors seen in recent experimental results by Fève et al., [Science 316, 1169 (2007)], such as the increase in maximum value of instantaneous current and the decrease in total amount of electrons pumped from the dot when the dot-electrode coupling increases.