Fermi super-Tonks-Girardeau state for attractive Fermi gases in an optical lattice

We demonstrate that a kind of highly excited state of strongly attractive Hubbard model, named of Fermi super-Tonks-Girardeau state, can be realized in the spin-1/2 Fermi optical lattice system by a sudden switch of interaction from the strongly repulsive regime to the strongly attractive regime. In contrast to the ground state of the attractive Hubbard model, such a state is the lowest scattering state with no pairing between attractive fermions. With the aid of Bethe-ansatz method, we calculate energies of both the Fermi Tonks-Girardeau gas and the Fermi super-Tonks-Girardeau state of spin-1/2 ultracold fermions and show that both energies approach to the same limit as the strength of the interaction goes to infinity. By exactly solving the quench dynamics of the Hubbard model, we demonstrate that the Fermi super-Tonks-Girardeau state can be transferred from the initial repulsive ground state very efficiently. This allows the experimental study of properties of Fermi super-Tonks-Girardeau gas in optical lattices.Comment: 7 pages, 7 figure

Efficient and accurate modeling of electron photoemission in nanostructures with TDDFT

We derive and extend the time-dependent surface-flux method introduced in [L. Tao, A. Scrinzi, New J. Phys. 14, 013021 (2012)] within a time-dependent density-functional theory (TDDFT) formalism and use it to calculate photoelectron spectra and angular distributions of atoms and molecules when excited by laser pulses. We present other, existing computational TDDFT methods that are suitable for the calculation of electron emission in compact spatial regions, and compare their results. We illustrate the performance of the new method by simulating strong-field ionization of C60 fullerene and discuss final state effects in the orbital reconstruction of planar organic molecules

Social networks and infectious disease: The Colorado Springs study

The social network paradigm provides a set of concepts and methods useful for studying the structure of a population through which infectious agents transmitted during close personal contact spread, and an opportunity to develop improved disease control programs. The research discussed was a first attempt to use a social network approach to better understand factors affecting the transmission of a variety of pathogens, including hepatitis B virus (HBV) and human immunodeficiency viruses (HIV), in population of prostitutes, injecting drug users (IDU) and their personal associates in a moderate-sized city (Colorado Springs, CO). Some of the challenges of studying large social networks in epidemiological research are described, some initial results reported and a new view of interconnections in an at risk population provided. Overall, for the first time in epidemiologic research a large number of individuals (over 600) were found connected to each other, directly or indirectly, using a network design. The average distance (along observed social relationships) between persons infected with HIV and susceptible persons was about three steps (3.1) in the core network region. All susceptibles in the core were within seven steps of HIV infection.epidemiologic models social networks HIV hepatitis B prostitutes injecting drug users contact tracing

GROWTH OF A GAS BUBBLE IN A STEADY DIFFUSION FIELD IN A TISSUE UNDERGOING DECOMPRESSION

This paper presents parameterized study on the growth of a convective gas bubble in tissues of a steady diffusion field. Resulting formulae are obtained analytically, which are valid for constant ambient pressure. It’s found that the growing bubble radius is proportional to initial bubble radius, initial concentration difference, diver’s average temperature and initial void fraction which is the dominant parameter, while it’s inversely proportional to surface tension, viscosity, density ratio and ambient pressure. Comparison to some previous work is performed

Curva de Phillips e macrodinâmica do capital ótimo Phillips curve and the macrodynamics of optimal capital

Este artigo apresenta novos argumentos para alguns dos fatos estilizados, recentemente, sobre a dinâmica da inflação, apontados por Mishkin (2007), quais sejam: a) a persistência dos choques de inflação estão declinando; b) a curva de Phillips esta se tornando mais horizontal e; c) a inflação tem se mostrado menos reativa à choques nos preços. É abordado o problema da determinação da oferta agregada em que alegamos que a versão novokeynesiana da curva de Phillips, apesar dos avanços, ainda não incorpora os determinantes da ampliação do produto potencial e, que esta inclusão é uma das explicações para os fatos estilizados (fato b), revelados recentemente por Mishkin.<br>This paper presents new arguments for some recent stylized facts about the dynamics of inflation shown by Mishkin (2007), which are: a) the persistence of inflation shocks are declining; b) the Phillips' curve of this becoming more horizontal and; c) inflation has been less reactive to shocks on prices. It addressed the problem of determining the aggregate supply where the new version of the Keynesian Phillips' curve, that despite progress, not yet incorporating the determinants of the expansion potential of the product and that this inclusion is one of the explanations for stylized facts (fact b ) revealed recently by Mishkin