The Effect of Watering Regimes on the Growth and Development of Alpinia Purpurata (Viell) K. Schum. Inflorescences

The objective of this research was to determine the water requirement of Alpinia purpurata (red ginger) to produce high quality inflorescences. A farm using overhead irrigation with impact sprinklers at 4.3 mm per hour for one hour three times per week proved superior to the drip irrigated three cultivars of Alpinia purpurata, red ginger, 'Eileen McDonald', and Ginoza No.__, were grown under different irrigation levels at the Waimanalo Research Station located in Waimanalo, Hawaii from August 1991 to May 1993. Five drip-irrigation treatments corresponded to replacement of 0.33 to 1.67 of pan evaporation. Weekly samples of the shoots were monitored to determine the stages of growth and development of the plant. The stages of inflorescence development in chronological order were: inflorescence initiation, appearance of color at the shoot tip, swelling of the inflorescence, appearance of the inflorescence, and harvest of the shoot. The influence of water application rates was monitored by stomatal conductance, relative water content, total leaf area per shoot, inflorescence diameter and length, shoot diameter and length, number of expanded leaves, and number of inflorescences per clump. Seasonal trends were compared with environmental data collected by a weather station. The components of the soil water balance were determined. The stages of inflorescence development were not affected by water application rates but were affected by the cultivars and seasonality. The average durations (weeks) for the appearance of color at the shoot tip, swelling of the inflorescence, appearance of the inflorescence, and harvest of the shoot were 20.8, 21.5, 23.2, and 26.4 respectively. The Ginoza cultivar took significantly longer from shoot emergence to all four stages compared to the other two cultivars. The Ginoza cultivar also produced the longest shoots, most number of expanded leaves, and shorter inflorescences than 'Eileen McDonald'. Shoots which emerged at the start of increasing temperatures and solar radiation (March and April) averaged shorter times to the four stages compared to shoots which emerged at the start of decreasing temperature and solar radiation (November). The highest irrigation treatment produced higher quality inflorescences, but all treatments appeared to experience frequent water stress due to deep drainage

Localized Asymmetric Atomic Matter Waves in Two-Component Bose-Einstein Condensates Coupled with Two Photon Microwave Field

We investigate localized atomic matter waves in two-component Bose-Einstein condensates coupled by the two photon microwave field. Interestingly, the oscillations of localized atomic matter waves will gradually decay and finally become non-oscillating behavior even if existing coupling field. In particular, atom numbers occupied in two different hyperfine spin states will appear asymmetric occupations after some time evolution.Comment: 4 pages, 4 figure

Measurement of the interaction strength in a Bose-Fermi mixture with 87Rb and 40K

A quantum degenerate, dilute gas mixture of bosonic and fermionic atoms was produced using 87Rb and 40K. The onset of degeneracy was confirmed by observing the spatial distribution of the gases after time-of-flight expansion. Further, the magnitude of the interspecies scattering length between the doubly spin polarized states of 87Rb and 40K, |a_RbK|, was determined from cross-dimensional thermal relaxation. The uncertainty in this collision measurement was greatly reduced by taking the ratio of interspecies and intraspecies relaxation rates, yielding |a_RbK| = 250 +/- 30 a_0, which is a lower value than what was reported in [M. Modugno et al., Phys. Rev. A 68, 043626 (2003)]. Using the value for |a_RbK| reported here, current T=0 theory would predict a threshold for mechanical instability that is inconsistent with the experimentally observed onset for sudden loss of fermions in [G. Modugno et al., Science 297, 2240 (2002)].Comment: RevTeX4 + 4 eps figures; Replaced with published versio

Cross-Dimensional relaxation in Bose-Fermi mixtures

We consider the equilibration rate for fermions in Bose-Fermi mixtures undergoing cross-dimensional rethermalization. Classical Monte Carlo simulations of the relaxation process are performed over a wide range of parameters, focusing on the effects of the mass difference between species and the degree of initial departure from equilibrium. A simple analysis based on Enskog's equation is developed and shown to be accurate over a variety of different parameter regimes. This allows predictions for mixtures of commonly used alkali atoms.Comment: 7 pages, 4 figures, uses Revtex 4. This is a companion paper to [PRA 70, 021601(R) (2004)] (cond-mat/0405419

Does matter wave amplification work for fermions?

We discuss the relationship between bosonic stimulation, density fluctuations, and matter wave gratings. It is shown that enhanced stimulated scattering, matter wave amplification and atomic four-wave mixing are in principle possible for fermionic or non-degenerate samples if they are prepared in a cooperative state. In practice, there are limitations by short coherence times.Comment: 5 pages, 1 figure

Atom-Molecule Laser Fed by Stimulated Three-Body Recombination

Using three-body recombination as the underlying process, we propose a method of coherently driving an atomic Bose-Einstein condensate (BEC) into a molecular BEC. Superradiant-like stimulation favors atom-to-molecule transitions when two atomic BECs collide at a resonant kinetic energy, the result being two molecular BEC clouds moving with well defined velocities. Potential applications include the construction of a molecule laser.Comment: 4 pgs, 3 figs, RevTeX4, submitted to PRL; Corrected numerical example

Direct evaporative cooling of 41K into a Bose-Einstein condensate

We have investigated the collisional properties of 41K atoms at ultracold temperature. To show the possibility to use 41K as a coolant, a Bose-Einstein condensate of 41K atoms in the stretched state (F=2, m_F=2) was created for the first time by direct evaporation in a magnetic trap. An upper bound of three body loss coefficient for atoms in the condensate was determined to be 4(2) 10^{-29} cm -6 s-1. A Feshbach resonance in the F=1, m_F=-1 state was observed at 51.42(5) G, which is in good agreement with theoretical prediction.Comment: 4 pages, 4 figure