Linear Absorption Spectrum of a Quantum Two-Dimensional Rotator Calculated Using a Rotationally Invariant System-Bath Hamiltonian

We consider a two-dimensional rigid rotator system coupled to a two-dimensional heat bath. The Caldeira-Leggett (Brownian) model for the rotator and the spin-Boson model have been used to describe such systems, but they do not possess rotational symmetry, they cannot describe the discretized rotational bands in absorption and emission spectra that have been found experimentally. Here, to address this problem, we introduce a rotationally invariant system-bath (RISB) model that is described by two sets of harmonic-oscillator baths independently coupled to the rigid rotator as sine and cosine functions of the rotator angle. Due to a difference in the energy discretization of the total Hamiltonian, the dynamics described by the RISB model differ significantly from those described by the rotational Caldeira-Legget (RCL) model, while both models reduce to the Langevin equation for a rotator in the classical limit. To demonstrate this point, we compute the rotational absorption spectrum defined by the linear response function of a rotator dipole. For this purpose, we derive a quantum master equation for the RISB model in the high-temperature Markovian case. We find that the spectral profiles of the calculated signals exhibit a transition from quantized rotational bands to a single peak after spectrum collapse. This is a significant finding, because previous approaches cannot describe such phenomena in a unified manner.Comment: 20 pages 1 figur

異なるスピードでの動的姿勢制御における若年者と高齢者の足関節周囲筋同時収縮の違い

広島大学(Hiroshima University)博士(保健学)Doctor of Philosophy in Health Sciencedoctora

Rapid Disease Progression of Advanced Non-small Cell Lung Cancer Five Months after Cessation of Pembrolizumab

We report a case of late-onset hyperprogressive disease after cessation of a PD-1 inhibitor. A male was diagnosed with metastatic lung adenocarcinoma with little progression for 2 months before treatment. He received pembrolizumab as a second-line treatment and was subsequently prescribed docetaxel for 3 months until a slight increase in pleural effusion. At the time of progression to docetaxel, he commenced prednisolone because of immune-system-related diarrhea. After that, his general condition rapidly worsened with severe fatigue and hypoxia. Computed tomography revealed a massive increase of pleural effusion and replacement of almost the entire liver with cancer over a period of 5 weeks

Analysis of Chromosome Behavior during Meiosis of Arabidopsis Polyploid Mutants

Polyploid lines were constructed from several diploid ecotypes of Arabidopsis thaliana by colchicine treatment. To confirm their ploidy by counting the chromosome number of the respective cells under a microscope, meiotic chromosomes of pollen mother cells were surface-spread on slide glasses and visualized by DAPI staining. It was clearly indicated that the tetraploid lines assumed by flowcytometry had 20 chromosomes, since 10 pairs of bivalents were observed on the metaphase I plate, and 2 sets of 10 chromosomes on metaphase II plates. As far as we analyzed through light microscopic observation, homologous chromosomes normally synapsed at the pachytene stage, congressed on the metaphase plate at metaphase I, and segregated reductionally to daughter cells at the anaphase I, and sister chromatids were separated to produce tetrads during meiosis II. Putting these results together with their fertility, the constructed tetraploid lines were concluded to undergo meiosis as normally as wild-type diploid plants, though the chromosome number was doubled

Effect of Polyploidizing Treatment on Chromosome Behavior during Meiosis of Arabidopsis thaliana

We observed chromosome behavior during meiosis of Arabidopsis thaliana justafter polyploidization. Two strains of A. thaliana, Columbia (Col) and Landsberg erecta(Ler), were treated with colchicine to induce polyploid lines, and the treated generationswere analyzed. Flow cytometric analysis revealed that a tetraploid line was obtained fromthe treated Col and an octoploid line from the treated Ler. Meiotic chromosomes of pollenmother cells of these polyploid lines were visualized by DAPI staining and observed. Bothlines underwent meiosis as normal, as did most of the established tetraploid lines on thewhole. At metaphase I, however, their numbers of bivalent chromosomes were fewer thanexpected and chromosome alignment of the octoploid was occasionally disturbed. Therewas no significant difference between the fertility of diploid and tetraploid, but that ofoctoploid was significantly reduced, which might be correlated with the disturbance ofchromosome configuration

Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments

In high-energy-density physics, including inertial fusion energy using high-power lasers, doping tracer atoms and deuteration of target materials play an important role in diagnosis. For example, a low-concentration Cu dopant acts as an x-ray source for electron temperature detection while a deuterium dopant acts as a neutron source for fusion reaction detection. However, the simultaneous achievement of Cu doping, a deuterated polymer, mechanical toughness and chemical robustness during the fabrication process is not so simple. In this study, we report the successful fabrication of a Cu-doped deuterated target. The obtained samples were characterized by inductively coupled plasma optical emission spectrometry, differential scanning calorimetry and Fourier transform infrared spectroscopy. Simultaneous measurements of Cu K-shell x-ray emission and beam fusion neutrons were demonstrated using a petawatt laser at Osaka University.Ikeda T., Kaneyasu Y., Hosokawa H., et al. Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments. Nuclear Fusion 63, 016010 (2023); https://doi.org/10.1088/1741-4326/aca2ba

Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

A counter-propagating laser-beam platform using a spherical plasma mirror was developed for the kilojoule-class petawatt LFEX laser. The temporal and spatial overlaps of the incoming and redirected beams were measured with an optical interferometer and an x-ray pinhole camera. The plasma mirror performance was evaluated by measuring fast electrons, ions, and neutrons generated in the counter-propagating laser interaction with a Cu-doped deuterated film on both sides. The reflectivity and peak intensity were estimated as ∼50% and ∼5 × 1018 W/cm2, respectively. The platform could enable studies of counter-streaming charged particles in high-energy-density plasmas for fundamental and inertial confinement fusion research.Kojima S., Abe Y., Miura E., et al. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system. Optics Express 30, 43491 (2022); https://doi.org/10.1364/oe.475945

Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

Polystyrene deuteride shell targets with two holes were imploded by the Gekko XII laser and additionally heated by the LFEX laser in a direct fast ignition experiment. In general, when an ultra-intense laser is injected into a blow-off plasma created by the imploding laser, electrons are generated far from the target core and the energies of electrons increase because the electron acceleration distance has been extended. The blow-off plasma moves not only to the vertical direction but to the lateral direction against the target surface. In a shell target with holes, a lower effective electron temperature can be realized by reducing the inflow of the implosion plasma onto the LFEX path, and high coupling efficiency can be expected. The energies of hot electrons and ions absorbed into the target core were calculated from the energy spectra using three electron energy spectrometers and a neutron time-of-flight measurement system, Mandala. The ions have a large contribution of 74% (electron heating of 4.9 J and ion heating of 14.1 J) to target heating in direct fast ignition

Direct fast heating efficiency of a counter-imploded core plasma employing a laser for fast ignition experiments (LFEX)

Fast heating efficiency when a pre-imploded core is directly heated with an ultraintense laser (heating laser) was investigated. \u27Direct heating\u27 means that a heating laser hits a pre-imploded core without applying either a laser guiding cone or an external field. The efficiency, η, is defined as the increase in the internal core energy divided by the energy of the heating laser. Six beams (output of 1.6 kJ) from the GEKKO XII (GXII) green laser system at the Institute of Laser Engineering (ILE), Osaka University were applied to implode a spherical deuterated polystyrene (CD) shell target to form a dense core. The DD-reacted protons and the core x-ray emissions showed a core density of 2.8 ± 0.7 g cm−3, or 2.6 times the solid density. Furthermore, DD-reacted thermal neutrons were utilized to estimate the core temperature between 600 and 750 eV. Thereafter, the core was directly heated by a laser for fast-ignition experiments (LFEX, an extremely energetic ultrashort pulse laser) at ILE with its axis lying along or perpendicular to the GXII bundle axis, respectively. The former and latter laser configurations were termed \u27axial\u27 and \u27transverse modes\u27, respectively. The η was estimated from three independent methods: (1) the core x-ray emission, (2) the thermal neutron yield, and (3) the runaway hot electron spectra. For the axial mode, 0.8%< η <2.1% at low power (low LFEX energy) and 0.4%< η <2.5% at high power (high LFEX energy). For the transverse mode, 2.6%< η <7% at low power and 1.5%< η <7.7% at high power. Their efficiencies were compared with that in the uniform implosion mode using 12 GXII beams, 6% < η <12%, which appeared near to the η for the transverse mode, except that the error bar is very large