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We propose a natural two-speed model for the phase dynamics of Si(111) 7x7 phase transition to high-temperature unreconstructed phase. We formulate the phase dynamics by using phase-field method and adaptive mesh refinement. Our simulated results show that a 7x7 island decays with its shape kept unchanged, and its area decay rate is shown to be a constant increasing with its initial area. Low-energy electron microscopy experiments concerned are explained, which confirms that the dimer chains and corner holes are broken first in the transition, and then the stacking fault is remedied slowly. This phase-field method is a reliable approach to phase dynamics of surface phase transitions.

Scanning tunneling microscope measurements on single crystals of Bi 2 Sr 2 CaCu 2 O 8 + x materials have shown that the d-wave superconductivity in cuprates has nanoscale inhomogeneities and is still robust in spite of theirpresence. We study the dynamics of Josephson coupling between such granular d-wave superconductors, focusing on the effect of nodal Cooper pairs and disorder. We find that the nodal Cooper pairs give rise to a power-law Josephson coupling which leads to the stabilization of the superconducting phase. Our findings suggest that the d-wave superconductivity in an array of grains is unexpectedly robust against a disordering transition, as observed in the experiments. Furthermore, we predict the existence of a planar Josephson-plasmon mode with characteristic frequency that decreases with temperature.

Recently two groups1–3 have described the observation of confined states in an annulus near the onset of convection in binary fluid mixtures. These confined states are characterized by the fact that for part of the annulus a convective pattern is visible — that is the envelope of the convective pattern assumes a finite value — whereas the rest of the container is in the heat conduction state. These observations are now under intense investigation theoretically4–6 and experimentally2,3.

We investigate the relative phase between two weakly interacting 1D condensates of bosonic atoms after suddenly switching on the tunnel-coupling. The following phase dynamics is governed by the quantum sine-Gordon equation. In the semiclassical limit of weak interactions, we observe the parametric amplification of quantum fluctuations leading to the formation of breathers with a finite lifetime. The typical lifetime and density of the these 'quasibreathers' are derived employing exact solutions of the classical sine-Gordon equation. Both depend on the initial relative phase between the condensates, which is considered as a tunable parameter., 7 pages, 5 figures

We have performed both Josephson and quasiparticle tunneling in vacuum tunnel junctions formed between a conventional superconducting scanning tunneling microscope tip and overdoped Bi2Sr2CaCu2O8+ single crystals. A Josephson current is observed with a peak centered at a small finite voltage due to the thermal-fluctuation-dominated superconducting phase dynamics. Josephson measurements at different surface locations yield local values for the Josephson ICRN product. Corresponding energy gap measurements were also performed and a surprising inverse correlation was observed between the local ICRN product and the local energy gap.

We propose a new type of Josephson junction formed by two superconductors close to the superconductor-Mott-insulator transition, one of which is doped with holes and the other is doped with electrons. A self-organized Mott-insulating depletion region is formed at the interface between two superconductors, giving rise to an asymmetric response of current to the external voltage. The collective excitations of the depletion region result in a novel phase dynamics that can be measured experimentally in the noise spectrum of the Josephson current.

We investigate three-junction SQUIDs which show voltage rectification if biased with an ac current drive with zero mean value. The Josephson phase across the SQUID experiences an effective ratchet potential, and the device acts as an efficient rocking ratchet, as demonstrated experimentally for adiabatic and nonadiabatic drive frequencies. For high-frequency drives the rectified voltage is quantized due to synchronization of the phase dynamics with the external drive. The experimental data are in excellent agreement with numerical simulations including thermal fluctuations.

We have studied the mass currents through a superfluid ${}^{3}\mathrm{He}$ Josephson weak link in the presence of an externally applied ac pressure modulation. Characteristic changes in the dc mass currents are observed whenever the superfluid Josephson frequency ${\ensuremath{\omega}}_{J}$ is an integer multiple of the ac modulation frequency $\ensuremath{\omega}$. The measured dependencies of these current changes on ac pressure amplitude are in excellent agreement with theory describing quantum phase dynamics of superfluid ${}^{3}\mathrm{He}$ weak links. These results establish the superfluid analog of the superconducting Shapiro effect.

It is shown that the B phase not only has a "phase dynamics" such as that in He II, but also an orbital dynamics somewhat similar to that of 3He-A or a nematic liquid cyrstal. The rederived B-phase hydrodynamic theory, complete with nonlinear terms, establishes the equivalence between rotations in orbital and spin spaces and shows the intriguing possibilities of generating a magnetization by mechanical rotations and of substituting the magnetic field with oscillating parallel plates in "NMR" experiments.