Plasmon spectrum of two-dimensional electron systems with Rashba spin-orbit interaction

The dielectric function and plasmon modes of a two-dimensional electron gas (2DEG) are studied in single- and double-quantum-well structures with Rashba spin-orbit interaction (RSOI) in the framework of the random-phase approximation. The RSOI splits each parabolic energy subband of a 2DEG into two nonparabolic spin branches and affects the electronic many-body correlation and dielectric properties of the 2DEG. The influence of the RSOI on the 2DEG plasmon spectrum in single quantum wells appear mainly in three ways: 1) an overall frequency lowering due to the energy band deformation; 2) a weak frequency oscillation stemming from the spin-split energy band; and 3)an enhancement of the Landau damping as a result of the emerging of the inter-branch single-particle-excitation spectrum. In double quantum wells, the above effects are enhanced for the optic plasmon mode but diminished for the acoustic one.Comment: 7 figure

Quakes in Solid Quark Stars

A starquake mechanism for pulsar glitches is developed in the solid quark star model. It is found that the general glitch natures (i.e., the glitch amplitudes and the time intervals) could be reproduced if solid quark matter, with high baryon density but low temperature, has properties of shear modulus \mu = 10^{30~34} erg/cm^3 and critical stress \sigma_c = 10^{18~24} erg/cm^3. The post-glitch behavior may represent a kind of damped oscillations.Comment: 11 pages, 4 figures (but Fig.3 is lost), a complete version can be obtained by http://vega.bac.pku.edu.cn/~rxxu/publications/index_P.htm, a new version to be published on Astroparticle Physic

Perturbation theory of von Neumann Entropy

In quantum information theory, von Neumann entropy plays an important role. The entropies can be obtained analytically only for a few states. In continuous variable system, even evaluating entropy numerically is not an easy task since the dimension is infinite. We develop the perturbation theory systematically for calculating von Neumann entropy of non-degenerate systems as well as degenerate systems. The result turns out to be a practical way of the expansion calculation of von Neumann entropy.Comment: 7 page

Tipstreaming of a drop in simple shear flow in the presence of surfactant

We have developed a multi-phase SPH method to simulate arbitrary interfaces containing surface active agents (surfactants) that locally change the properties of the interface, such the surface tension coefficient. Our method incorporates the effects of surface diffusion, transport of surfactant from/to the bulk phase to/from the interface and diffusion in the bulk phase. Neglecting transport mechanisms, we use this method to study the impact of insoluble surfactants on drop deformation and breakup in simple shear flow and present the results in a fluid dynamics video.Comment: Two videos are included for the Gallery of Fluid Motion of the APS DFD Meeting 201