Stability of Q-balls and Catastrophe

We propose a practical method for analyzing stability of Q-balls for the whole parameter space, which includes the intermediate region between the thin-wall limit and thick-wall limit as well as Q-bubbles (Q-balls in false vacuum), using the catastrophe theory. We apply our method to the two concrete models, $V_3=m^2\phi^2/2-\mu\phi^3+\lambda\phi^4$ and $V_4=m^2\phi^2/2-\lambda\phi^4+\phi^6/M^2$. We find that $V_3$ and $V_4$ Models fall into {\it fold catastrophe} and {\it cusp catastrophe}, respectively, and their stability structures are quite different from each other.Comment: 9 pages, 4 figures, some discussions and references added, to apear in Prog. Theor. Phy

Efficient virus-induced gene silencing in apple, pear and Japanese pear using Apple latent spherical virus vectors

<p>Abstract</p> <p>Background</p> <p>Virus-induced gene silencing (VIGS) is an effective technology for the analysis of gene functions in plants. Though there are many reports on virus vectors for VIGS in plants, no VIGS vectors available for <it>Rosaceae </it>fruit trees were reported so far. We present an effective VIGS system in apple, pear, and Japanese pear using <it>Apple latent spherical virus </it>(ALSV) vectors.</p> <p>Results</p> <p>Inoculation of ALSV vectors carrying a partial sequence of endogenous genes from apple [ribulose-1, 5-bisphosphate carboxylase small subunit (<it>rbcS</it>), alpha subunit of chloroplast chaperonin (<it>CPN60a</it>), elongation factor 1 alpha (<it>EF-1a</it>), or actin] to the cotyledons of seeds by a particle bombardment induced highly uniform knock-down phenotypes of each gene on the true leaves of seedlings from 2~3 weeks after inoculation. These silencing phenotypes continued for several months. Northern blot and RT-PCR analyses of leaves infected with ALSV containing a fragment of <it>rbcS </it>gene showed that the levels of <it>rbcS</it>-mRNA drastically decreased in the infected apple and pear leaves, and, in reverse, <it>rbcS-</it>siRNAs were generated in the infected leaves. In addition, some of apple seedlings inoculated with ALSV vector carrying a partial sequence of a <it>TERMINAL FLOWER 1 </it>gene of apple (<it>MdTFL1</it>) showed precocious flowering which is expected as a knock-down phenotype of the silencing of <it>MdTFL1 </it>gene.</p> <p>Conclusions</p> <p>The ALSV-based VIGS system developed have provides a valuable new addition to the tool box for functional genomics in apple, pear, and Japanese pear.</p

High-fidelity conversion of photonic quantum information to telecommunication wavelength with superconducting single-photon detectors

We experimentally demonstrate a high-fidelity visible-to-telecommunication wavelength conversion of a photon by using a solid-state-based difference frequency generation. In the experiment, one half of a pico-second visible entangled photon pair at 780 nm is converted to a 1522-nm photon, resulting in the entangled photon pair between 780 nm and 1522 nm. Using superconducting single-photon detectors with low dark count rates and small timing jitters, we selectively observed well-defined temporal modes containing the two photons. We achieved a fidelity of $0.93 \pm 0.04$ after the wavelength conversion, indicating that our solid-state-based scheme can be used for faithful frequency down-conversion of visible photons emitted from quantum memories composed of various media.Comment: 5 pages, 4 figure

On Detection of Black Hole Quasi-Normal Ringdowns: Detection Efficiency and Waveform Parameter Determination in Matched Filtering

Gravitational radiation from a slightly distorted black hole with ringdown waveform is well understood in general relativity. It provides a probe for direct observation of black holes and determination of their physical parameters, masses and angular momenta (Kerr parameters). For ringdown searches using data of gravitational wave detectors, matched filtering technique is useful. In this paper, we describe studies on problems in matched filtering analysis in realistic gravitational wave searches using observational data. Above all, we focus on template constructions, matches or signal-to-noise ratios (SNRs), detection probabilities for Galactic events, and accuracies in evaluation of waveform parameters or black hole hairs. We have performed matched filtering analysis for artificial ringdown signals which are generated with Monte-Carlo technique and injected into the TAMA300 observational data. It is shown that with TAMA300 sensitivity, the detection probability for Galactic ringdown events is about 50% for black holes of masses greater than $20 M_{\odot}$ with SNR $> 10$. The accuracies in waveform parameter estimations are found to be consistent with the template spacings, and resolutions for black hole masses and the Kerr parameters are evaluated as a few % and $\sim 40$, respectively. They can be improved up to $< 0.9$ and $< 24$ for events of ${\rm SNR} \ge 10$ by using fine-meshed template bank in the hierarchical search strategy.Comment: 10 pages, 10 figure