Out-of-time-order correlators in quantum mechanics

The out-of-time-order correlator (OTOC) is considered as a measure of quantum chaos. We formulate how to calculate the OTOC for quantum mechanics with a general Hamiltonian. We demonstrate explicit calculations of OTOCs for a harmonic oscillator, a particle in a one-dimensional box, a circle billiard and stadium billiards. For the first two cases, OTOCs are periodic in time because of their commensurable energy spectra. For the circle and stadium billiards, they are not recursive but saturate to constant values which are linear in temperature. Although the stadium billiard is a typical example of the classical chaos, an expected exponential growth of the OTOC is not found. We also discuss the classical limit of the OTOC. Analysis of a time evolution of a wavepacket in a box shows that the OTOC can deviate from its classical value at a time much earlier than the Ehrenfest time.Comment: 30 pages, 13 figure

Multiplex Genome Editing in Tomato

Several expression systems for multiple guide RNA (gRNAs) have been developed in the CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9) system to induce multiple-gene modifications in plants. Here, we evaluated mutation efficiencies in the tomato genome using multiplex CRISPR/Cas9 vectors consisting of various Cas9 expression promoters with multiple gRNA expression combinations. In transgenic tomato calli induced with these vectors, mutation patterns varied depending on the promoters used to express Cas9. By using the tomato ELONGATION FACTOR-1α (SlEF1α) promoter to drive Cas9, occurrence of various types of mutations with high efficiency was detected in the tomato genome. Furthermore, sequence analysis showed that the majority of mutations using the multiplex system with the SlEF1α promoter corresponded to specific mutation pattern of deletions produced by self-ligation at two target sites of CRISPR/Cas9 with low mosaic mutations. These results suggest that optimizing the Cas9 expression promoter used in CRISPR/Cas9-mediated mutation improves multiplex genome editing, and could be used effectively to disrupt functional domains precisely in the tomato genome

Soft Tissue Myoepithelioma of the Shoulder

Soft tissue myoepitheliomas are often misdiagnosed due to their rarity. Herein, we describe a case of soft tissue myoepithelioma of the shoulder. A 72-year-old woman had a suspected sarcoma on her shoulder and under-went open biopsy. She was referred to our hospital, where the tumor was widely resected and the diagnosis of myoepithelioma was histologically confirmed. No recurrence has been observed in the 3 years since the sur-gery. Careful and prompt planning is necessary for the effective treatment of myoepithelioma

Development of a low-alpha-emitting {\mu}-PIC for NEWAGE direction-sensitive dark-matter search

NEWAGE is a direction-sensitive dark-matter-search experiment that uses a micro-patterned gaseous detector, or {\mu}-PIC, as the readout. The main background sources are {\alpha}-rays from radioactive contaminants in the {\mu}-PIC. We have therefore developed a low-alpha-emitting {\mu}-PICs and measured its performances. We measured the surface {\alpha}-ray emission rate of the {\mu}-PIC in the Kamioka mine using a surface {\alpha}-ray counter based on a micro TPC.Comment: 6 pages, 4 figure

The Stellar Mass, Star Formation Rate and Dark Matter Halo Properties of LAEs at z∼2z\sim2

We present average stellar population properties and dark matter halo masses of $z \sim 2$ \lya emitters (LAEs) from SED fitting and clustering analysis, respectively, using $\simeq$ $1250$ objects ($NB387\le25.5$) in four separate fields of $\simeq 1$ deg$^2$ in total. With an average stellar mass of $10.2\, \pm\, 1.8\times 10^8\ {\mathrm M_\odot}$ and star formation rate of $3.4\, \pm\, 0.4\ {\mathrm M_\odot}\ {\rm yr^{-1}}$, the LAEs lie on an extrapolation of the star-formation main sequence (MS) to low stellar mass. Their effective dark matter halo mass is estimated to be $4.0_{-2.9}^{+5.1} \times 10^{10}\ {\mathrm M_\odot}$with an effective bias of$1.22^{+0.16}_{-0.18}$which is lower than that of$z \sim 2$LAEs ($1.8\, \pm\, 0.3$), obtained by a previous study based on a three times smaller survey area, with a probability of$96\%. However, the difference in the bias values can be explained if cosmic variance is taken into account. If such a low halo mass implies a low HI gas mass, this result appears to be consistent with the observations of a high \lya escape fraction. With the low halo masses and ongoing star formation, our LAEs have a relatively high stellar-to-halo mass ratio (SHMR) and a high efficiency of converting baryons into stars. The extended Press-Schechter formalism predicts that at z=0$our LAEs are typically embedded in halos with masses similar to that of the Large Magellanic Cloud (LMC); they will also have similar SHMRs to the LMC, if their SFRs are largely suppressed after$z \sim 2$ as some previous studies have reported for the LMC itself.Comment: 34 pages, 15 figures, 6 tables. Accepted for publication in PAS

Study of Negative-Ion TPC Using {\mu}-PIC for Directional Dark Matter Search

Negative-ion time projection chambers(TPCs) have been studied for low-rate and high-resolution applications such as dark matter search experiments. Recently, a full volume fiducialization in a self-triggering TPC was realized. This innovative technology demonstrated a significant reduction in the background with MWPC-TPCs. We studied negative-ion TPC using the {\mu}-PIC+GEM system and obtained sufficient gas gain with CS$_{2}$gas and SF$_{6}$ gas at low pressures. We expect an improvement in detector sensitivity and angular resolution with better electronics