Memory Effect and Fast Spinodal Decomposition

We consider the modification of the Cahn-Hilliard equation when a time delay process through a memory function is taken into account. We then study the process of spinodal decomposition in fast phase transitions associated with a conserved order parameter. The introduced memory effect plays an important role to obtain a finite group velocity. Then, we discuss the constraint for the parameters to satisfy causality. The memory effect is seen to affect the dynamics of phase transition at short times and has the effect of delaying, in a significant way, the process of rapid growth of the order parameter that follows a quench into the spinodal region.Comment: 4 pages, 3 eps figure

Latino Protestants and Their Political and Social Engagement (Chapter Six of Latino Protestants in America: Growing and Diverse)

Excerpt: On a rainy early spring morning in a modest brick Presbyterian church just outside the Fruitvale neighborhood of Oakland, California, sixtyfour worshippers gather. The entire worship is in Spanish. During the sermon, the pastor makes a passing reference to how few of the attenders now live in Oakland proper, that many have to drive farther than ever for church services. The implicit message: the leadership of the church realizes that gentrification of San Francisco has spilled over the Bay Bridge and now threatens the availability of affordable housing throughout Oakland. In response, the congregation has started programs that offer legal advice for responding to rent-hiking landlords and identifying housing options around the city. Though resources and attenders tend to be somewhat scarce, the leadership has creatively organized in an effort to address the structural and policy concerns of housing. Beyond that, the pastor proudly notes that this church readily offers immigration status services, computer classes, and English classes

Modeling Three and Four Coupled Phase Qubits

The Josephson junction phase qubit has been shown to be a viable candidate for quantum computation. In recent years, the two coupled phase system has been extensively studied theoretically and experimentally. We have analyzed the quantum behavior of three and four capacitively-coupled phase qubits with different possible configurations, using a two-level system model. Energy levels and eigenstates have been calculated as a function of bias current and detuning. The properties of these simple networks are discussed

D Mesons in Nuclear Matter: A DN Coupled-Channel Equations Approach

A set of coupled two-body scattering equations is solved for the DN system embedded in an iso-symmetric nuclear matter. The in-medium behavior of charmed D mesons: (D^+,D^0), is investigated from the self-consistent solution within this scheme. The effective meson-baryon Lagrangian in charm quantum number one sector, the key ingredient in the present study, is adopted from a recent model by Hofmann and Lutz which has aimed at combining the charmed meson degree of freedom in a consistent manner with chiral unitary models. After a critical examination, the original model is modified in several important aspects, such as the method of regularization, in order to be more consistent and practical for our objective. The resultant interaction is used to reproduce the position and width of the s-wave \Lambda_c(2593) resonance in the isospin zero DN channel. In the isospin one channel, it generates a rather wide resonance at \~2770 MeV. The corresponding in-medium solution is then sought by incorporating Pauli blocking and the D- and \pi-meson dressing self-consistently. At normal nuclear matter density, the resultant \Lambda_c (2593) is found to stay narrow and shifted at a lower energy, while the I=1 resonance is lowered in position as well and broadened considerably. The possible implication of our findings on the J/\Psi suppression, etc. in relativistic heavy ion collisions is briefly discussed.Comment: 30 pages, 8 eps figures, some typos and coefficients corrected, published in Phys. Rev.

Direct 3D Tomographic Reconstruction and Phase-Retrieval of Far-Field Coherent Diffraction Patterns

We present an alternative numerical reconstruction algorithm for direct tomographic reconstruction of a sample refractive indices from the measured intensities of its far-field coherent diffraction patterns. We formulate the well-known phase-retrieval problem in ptychography in a tomographic framework which allows for simultaneous reconstruction of the illumination function and the sample refractive indices in three dimensions. Our iterative reconstruction algorithm is based on the Levenberg-Marquardt algorithm. We demonstrate the performance of our proposed method with simulation studies

K- absorption in nuclei by two and three nucleons

It will be shown that the peaks in the (Lambda p) and (Lambda d) invariant mass distributions, observed in recent FINUDA experiments and claimed to be signals of deeply bound kaonic states, are naturally explained in terms of K- absorption by two or three nucleons leaving the rest of the original nuclei as spectator. For reactions on heavy nuclei, the subsequent interactions of the particles produced in the primary absorption process with the residual nucleus play an important role. Our analyses leads to the conclusion that at present there is no experimental evidence of deeply bound K- state in nuclei. Although the FINUDA experiments have been done for reasons which are not supported a posteriori, some new physics can be extracted from the data.Comment: 6 pages, 5 figures. Talk presented at the International Conference on Exotic Atoms "EXA 2008", Vienna, Austria, September 15-18, 200

Finite temperature effects on the antikaon optical potential

By solving the Bethe-Goldstone equation, we have obtained the $\bar{K}$ optical potential from the $\bar{K}N$ effective interaction in nuclear matter at T=0. We have extended the model by incorporating finite temperature effects in order to adapt our calculations to the experimental conditions in heavy-ion collisions. In the rank of densities ($0-2\rho_0$), the finite temperature $\bar{K}$ optical potential shows a smooth behaviour if we compare it to the T=0 outcome. Our model has also been applied to the study of the ratio between $K^+$ and $K^-$ produced at GSI with $T$ around 70 MeV. Our results point at the necessity of introducing an attractive $\bar{K}$ optical potential.Comment: 7 pages, 4 figures. Contribution to the proceedings of Mesons & Light Nuclei '01 (2-6th July, Prague

Latest results for the antikaon-nucleon optical potential

The key question of this letter is whether the K-nucleus optical potential is deep, as it is prefered by the phenomenological fits to kaonic atoms data, or shallow, as it comes out from unitary chiral model calculations. The current experimental situation is reviewed.Comment: 3 pages, 1 figure. Presented at the 21st European Conference on the Few-Body problems in Physics (EFB21), Salamanca, Spain, August 29 - September 3, 201