Luther-Emery Phase and Atomic-Density Waves in a Trapped Fermion Gas

The Luther-Emery liquid is a state of matter that is predicted to occur in one-dimensional systems of interacting fermions and is characterized by a gapless charge spectrum and a gapped spin spectrum. In this Letter we discuss a realization of the Luther-Emery phase in a trapped cold-atom gas. We study by means of the density-matrix renormalization-group technique a two-component atomic Fermi gas with attractive interactions subject to parabolic trapping inside an optical lattice. We demonstrate how this system exhibits compound phases characterized by the coexistence of spin pairing and atomic-density waves. A smooth crossover occurs with increasing magnitude of the atom-atom attraction to a state in which tightly bound spin-singlet dimers occupy the center of the trap. The existence of atomic-density waves could be detected in the elastic contribution to the light-scattering diffraction pattern.Comment: 10 pages, 3 figures, 1 Table, submitted to Phys. Rev. on July 25th 200

Dynamics of a Tonks-Girardeau gas released from a hard-wall trap

We study the expansion dynamics of a Tonks-Girardeau gas released from a hard wall trap. Using the Fermi-Bose map, the density profile is found analytically and shown to differ from that one of a classical gas in the microcanonical ensemble even at macroscopic level, for any observation time larger than a critical time. The relevant time scale arises as a consequence of fermionization.Comment: 4 pages, 6 figure

Diffraction in time of a confined particle and its Bohmian paths

Diffraction in time of a particle confined in a box which its walls are removed suddenly at $t=0$ is studied. The solution of the time-dependent Schr\"{o}dinger equation is discussed analytically and numerically for various initial wavefunctions. In each case Bohmian trajectories of the particles are computed and also the mean arrival time at a given location is studied as a function of the initial state.Comment: 8 pages, 6 figure

Open inflationary universes in a brane world cosmology

In this paper, we study a type of one-field model for open inflationary universe models in the context of the brane world models. In the scenario of a one-bubble universe model, we determine and characterize the existence of the Coleman-De Lucia instanton, together with the period of inflation after tunneling has occurred. Our results are compared to those found in the Einstein theory of Relativistic Models.Comment: 8 pages, 4 Figures, accepted in Physical Review

Quantum matter wave dynamics with moving mirrors

When a stationary reflecting wall acting as a perfect mirror for an atomic beam with well defined incident velocity is suddenly removed, the density profile develops during the time evolution an oscillatory pattern known as diffraction in time. The interference fringes are suppressed or their visibility is diminished by several effects such as averaging over a distribution of incident velocities, apodization of the aperture function, atom-atom interactions, imperfect reflection or environmental noise. However, when the mirror moves with finite velocity along the direction of propagation of the beam, the visibility of the fringes is enhanced. For mirror velocities below beam velocity, as used for slowing down the beam, the matter wave splits into three regions separated by space-time points with classical analogues. For mirror velocities above beam velocity a visibility enhancement occurs without a classical counterpart. When the velocity of the beam approaches that of the mirror the density oscillations rise by a factor 1.8 over the stationary value.Comment: 5.2 pages, 6 figure

Multivariable Anti-Windup and Bumpless Transfer: A General Theory

A general theory is developed to address the anti-windup/bumpless transfer (AWBT) problem. Analysis results applicable to any linear time invariant system subject to plant input limitations and substitutions are presented. Quantitative performance objectives for AWBT compensation are outlined and several proposed AWBT methods are evaluated in light of these objectives. A synthesis procedure which highlights the performance trade-offs for AWBT compensation design is outlined

Matter-wave diffraction in time with a linear potential

Diffraction in time of matter waves incident on a shutter which is removed at time $t=0$ is studied in the presence of a linear potential. The solution is also discussed in phase space in terms of the Wigner function. An alternative configuration relevant to current experiments where particles are released from a hard wall trap is also analyzed for single-particle states and for a Tonks-Girardeau gas.Comment: 11 pages, 6 figure

Supranutritional doses of vitamin E to improve lamb meat quality

Vitamin E is a fat-soluble antioxidant, therefore, it can be stored in any fat depot in the body, where it exerts a potent chain-breaking antioxidant effect. Moreover, the antioxidant activity of vitamin E-like compounds is also present in meat post mortem. The deposition of tocopherol in the muscle depends on the dosage, the source, and the period of supplementation, so different dosage-time combinations have been developed. Vitamin E does not affect production parameters if minimum requirements for function and growth are satisfied, but it could influence lamb fatty acid profile. During display, it protects PUFA from degradation, reducing lipid oxidation and, therefore, delaying discolouration. Furthermore, vitamin E would indirectly affect the development of lamb aroma by reducing protein and lipid oxidation. To facilitate optimal supplementation rates by producers and retailers, the present paper reviews vitamin E chemistry, biochemistry, nutrition and its ability to maintain lamb quality

Modelling the dynamics of agroforestry adoption in the uplands of Southern Philippines using companion modelling approach

A model was developed following an iterative process based on repetitive back-and-forth steps between the model and field activities. A Multi Agent System (MAS) was integrated with a Role-Playing Game (RPG) to understand the dynamics of agroforestry adoption in Claveria, Misamis Oriental. The model simulated and observed different scenarios: cumulative income of agroforestry adopters and non-adopters, impact of market information on farm income, and neighbour effects on the spread of agroforestry adoption. Results of the computer simulations were verified using farmer games and focus group discussions. Agroforestry and non-agroforestry farmers were invited to participate in the role-playing game in order to understand more precisely and validate the model. During the conduct of the role-playing game, the individual behaviour of agents under a number of scenarios and the properties of the system emerging from their interactions were examined and discussed among the players. The model scenarios and role-playing game can serve as a decision support for policymakers, farmers and other stakeholders towards sustainable management of resources. It is envisioned to produce information useful for understanding the decision-making strategies of farmers with regard to agroforestry adoption that can be essential to the success of efforts to address the sustainability of upland areas in the Philippines and elsewhere in south-east Asia