Final-state read-out of exciton qubits by observing resonantly excited photoluminescence in quantum dots

We report on a new approach to detect excitonic qubits in semiconductor quantum dots by observing spontaneous emissions from the relevant qubit level. The ground state of excitons is resonantly excited by picosecond optical pulses. Emissions from the same state are temporally resolved with picosecond time resolution. To capture weak emissions, we greatly suppress the elastic scattering of excitation beams, by applying obliquely incident geometry to the micro photoluminescence set-up. Rabi oscillations of the ground-state excitons appear to be involved in the dependence of emission intensity on excitation amplitude.Comment: 4 pages, 4 figures, to appear in Appl. Phys. Let

Mixtures of Bose gases confined in concentrically coupled annular traps

A two-component Bose-Einstein condensate confined in an axially-symmetric potential with two local minima, resembling two concentric annular traps, is investigated. The system shows a number of quantum phase transitions that result from the competition between phase coexistence, and radial/azimuthal phase separation. The ground-state phase diagram, as well as the rotational properties, including the (meta)stability of currents in this system, are analysed.Comment: 6 pages, 5 figures, minor revision

Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots

We report strong heavy hole-light mixing in GaAs quantum dots grown by droplet epitaxy. Using the neutral and charged exciton emission as a monitor we observe the direct consequence of quantum dot symmetry reduction in this strain free system. By fitting the polar diagram of the emission with simple analytical expressions obtained from k$\cdot$p theory we are able to extract the mixing that arises from the heavy-light hole coupling due to the geometrical asymmetry of the quantum dot.Comment: 4 pages, 2 figure

Randomly Diluted e_g Orbital-Ordered Systems

Dilution effects on the long-range ordered state of the doubly degenerate $e_g$ orbital are investigated. Quenched impurities without the orbital degree of freedom are introduced in the orbital model where the long-range order is realized by the order-from-disorder mechanism. It is shown by the Monte-Carlo simulation and the cluster-expansion method that a decrease in the orbital ordering temperature by dilution is remarkable in comparison with that in the randomly diluted spin models. Tiltings of orbitals around impurity cause this unique dilution effects on the orbital systems. The present theory provides a new view point for the recent experiments in KCu$_{1-x}$Zn$_x$F$_3$.Comment: 4 pages, 4 figure

Effect of The Inclusion of Butterfly Pea (Clitoria ternatea) and Green Sea Weed (Ulva lactuca) in The Complete Feed on The Concentration of Blood Metabolites of Male Kacang Goats

This experiment aimed to investigate the effect of including  Clitoria ternatea and Ulva lactuca in the complete feed on the concentration of blood metabolites of male kacang goats. Four male kacang goats were involved in this experiment arranged following a Latin Square Design with 4 treatments and 4 periods as replication. The treatments were R0= native grass hay 60%+concentrate 40%, R1= native grass hay 30%+concentrate 40%+ Clitoria ternatea 30%, R2= native grass hay 30%+concentrate 40%+ Clitoria ternatea 15%+ Ulva lactuca 15% and R3= native grass hay 30%+ concentrate 40%+Ulva lactuca 30%. Data were analyzed using analysis of variance (ANOVA) and followed by the Duncan Multiple Range Test when significant differences were found. The results showed that  feeding a complete feed containing  Clitoria ternatea and Ulva lactuca did not significantly (P>0,05) affect the concentration of urea, glucose and  plasm total protein in the blood of male kacang goats. Therefore, it can be concluded the inclusion of Clitoria ternatea and Ulva lactuca has no effect on the concentration of blood metabolites in male kacang goats

Bunching visibility for correlated photons from single GaAs quantum dots

We study photon bunching phenomena associated with biexciton-exciton cascade in single GaAs self-assembled quantum dots. Experiments carried out with a pulsed excitation source show that significant bunching is only detectable at very low excitation, where the typical intensity of photon streams is less than the half of their saturation value. Our findings are qualitatively understood with a model which accounts for Poissonian statistics in the number of excitons, predicting the height of a bunching peak being determined by the inverse of probability of finding more than one exciton.Comment: 6 pages, 6 figs to appear in Phys. Rev.

Agrobacterium Tumefaciens-Mediated Transformation of Perennial Ryegrass (\u3ci\u3eLolium Perenne\u3c/i\u3e L.)

An Agrobacterium tumefaciens-mediated transformation method has several advantages. However, this method has no example of success in perennial ryegrass (Lolium perenne L.). Since Lolium species are outcrossing, one cultivar consists of many genotypes. Each genotype can show a different ability for callus formation and plant regeneration (Takahashi et al., 2004). Thus, it is important to select a good genotype for efficient and stable transformation. If the plant is maintained in vitro, we can perform transformation using calli induced from shoot tips of the same genotype at any time. Our objective is to confirm an A. tumefaciens-mediated transformation method for perennial ryegrass and to screen for suitable genotype