Observation of an Inner-Shell Orbital Clock Transition in Neutral Ytterbium Atoms

内殻電子が励起する時計遷移の初観測に成功 --新奇な光格子時計を用いた超高感度な新物理探索へ--. 京都大学プレスリリース. 2023-04-17.We observe a weakly allowed optical transition of atomic ytterbium from the ground state to the metastable state 4f¹³5d6s² (J=2) for all five bosonic and two fermionic isotopes with resolved Zeeman and hyperfine structures. This inner-shell orbital transition has been proposed as a new frequency standard as well as a quantum sensor for new physics. We find magic wavelengths through the measurement of the scalar and tensor polarizabilities and reveal that the measured trap lifetime in a three-dimensional optical lattice is 1.9(1) s, which is crucial for precision measurements. We also determine the g factor by an interleaved measurement, consistent with our relativistic atomic calculation. This work opens the possibility of an optical lattice clock with improved stability and accuracy as well as novel approaches for physics beyond the standard model

Examination of High-Torque Sandwich-Type Spherical Ultrasonic Motor Using with High-Power Multimode Annular Vibrating Stator

Spherical ultrasonic motors (SUSMs) that can operate with multiple degrees of freedom (MDOF) using only a single stator have high holding torque and high torque at low speed, which makes reduction gearing unnecessary. The simple structure of MDOF-SUSMs makes them useful as compact actuators, but their development is still insufficient for applications such as joints of humanoid robots and other systems that require MDOF and high torque. To increase the torque of a sandwich-type MDOF-SUSM, we have not only made the vibrating stator and spherical rotor larger but also improved the structure using three design concepts: (1) increasing the strength of all three vibration modes using multilayered piezoelectric actuators (MPAs) embedded in the stator, (2) enhancing the rigidity of the friction driving portion of the stator for transmitting more vibration force to the friction-driven rotor surface, and (3) making the support mechanism more stable. An MDOF-SUSM prototype was tested, and the maximum torques of rotation around the X(Y)-axis and Z-axis were measured as 1.48 N?m and 2.05 N?m, respectively. Moreover, the values for torque per unit weight of the stator were obtained as 0.87 N?m/kg for the X(Y)-axis and 1.20 N?m/kg for the Z-axis. These are larger than values reported for any other sandwich-type MDOF-SUSM of which we are aware. Hence, the new design concepts were shown to be effective for increasing torque. In addition, we measured the transient response and calculated the load characteristics of rotation around the rotor’s three orthogonal axes

pH-Responsive Aqueous Bubbles Stabilized With Polymer Particles Carrying Poly(4-vinylpyridine) Colloidal Stabilizer

Free radical dispersion polymerization was conducted to synthesize near-monodispersed, micrometer-sized polystyrene (PS) particles carrying pH-responsive poly(4-vinylpyridine) (P4VP) colloidal stabilizer (P4VP-PS particles). The P4VP-PS particles were extensively characterized in terms of morphology, size, size distribution, chemical composition, surface chemistry, and pH-response using optical and scanning electron microscopies, elemental microanalysis, X-ray photoelectron spectroscopy, laser diffraction particle size analysis, and zeta potential measurement. The P4VP-PS particles can work as a pH-responsive stabilizer of aqueous bubbles by adsorption at the air-water interface. At and above pH 4.0, where the particles have partially protonated/non-protonated P4VP stabilizer with relatively hydrophobic character, particle-stabilized bubbles were formed. Optical and scanning electron microscopy studies confirmed that the P4VP-PS particles were adsorbed at the air-water interface of the bubbles in aqueous media. At and below pH 3.0, where the particles have cationic P4VP stabilizer with water-soluble character, no bubble was formed. Rapid disruption of the bubbles can be induced by decreasing the pH; the addition of acid caused the in situ protonation of pyridine groups in P4VP, which impart water-soluble character to the P4VP stabilizer, and the P4VP-PS particles were desorbed from the air-water interface. The bubble stabilization/destabilization cycles could be repeated at least five times

ETS-VIIIを利用した災害医療支援のための立体画像伝送の研究

It is pointed out that a lot of people are dead or injured, and the functions of the infrastructure are lost such as the cellular phone, the gas , water service, electricity, and roads, when the communication network system on the ground is broken down by wide-scale disaster. In order to overcome such inconvenient conditions, the construction of Tel-Radiology system not depending on the situations of the ground should be established rapidly. In addition, if 3D image technology is applied for Tel-Radiology, it may lead to the contribution of the triage to the efficiently improved operations in several areas. In this paper, we studied the capability of 3D image technology applying to Tel-Radiology. As a result of sufficient investment of bit stream data transmission of stereo 3D moving pictures employed the ETS-VIII satellite , it is found that the proposed system function well in the experiment assuming a telemedicine.

Observation of Nonlinearity of Generalized King Plot in the Search for New Boson

新粒子探索のための量子センサー --原子スペクトルの精密分光から基礎物理法則に迫る--. 京都大学プレスリリース. 2022-05-12.We measure isotope shifts for neutral Yb isotopes on an ultranarrow optical clock transition ¹S₀ - ³P₀ with an accuracy of a few hertz. Combined with one of the recently reported isotope-shift measurements of Yb⁺ on two optical transitions, the result allows us to construct the King plots --a set of scaled isotope shifts data on two different optical transitions plotted in two-dimensional plane. When only the leading-order terms of isotope shifts are taken into account, a King plot should exhibit a linear relation as a result of elimination of the leading nuclear-size dependence. Extremely large nonlinearity unexplainable by a quadratic field shift is revealed, which was proposed previously as a source of the observed nonlinearity of the King plot. We further construct the generalized King plot with three optical transitions so that we can eliminate the contribution arising from a higher-order effect within the standard model. Our analysis of the generalized King plot shows a deviation from linearity at the 3σ level, indicating that there exist at least two higher-order contributions in the measured isotope shifts. Under reasonable assumptions, we obtain the upper bound of the product of the couplings for a new boson, mediating a force between electrons and neutrons --|yeyn|/(ℏc)<1×10⁻¹⁰ for the mass less than 1 keV-- with the 95% confidence level, providing an important step toward probing new physics via isotope-shift spectroscopy

Real‐world clinical practice of pulmonary arterial hypertension in Japan: Insights from a large administrative database

Abstract Pulmonary arterial hypertension (PAH) is a fatal disease that often occurs at an early age. In recent years, aggressive treatment with multiple drugs from the early‐stage diagnosis is expected to improve the prognosis. Indeed, a high rate of initial combination therapy and excellent treatment outcomes have been reported from specialized centers for PAH in Japan. However, information on PAH epidemiology, including non‐PAH specialized centers in Japan, is unclear. To address the above, we conducted a retrospective observational cohort study from April 2008 to September 2020 using real‐world evidence from a large‐scale administrative database (Medical Data Vision) to examine baseline characteristics, comorbidities, and treatment profiles of Japanese patients with PAH. Five hundred and eighteen patients with PAH (treatment‐naive PAH, age 67.2 ± 15.9) were identified through our comprehensive approach which combined PAH disease codes, medications, and diagnostic procedures. Moreover, we showed that a larger proportion of patients received monotherapy in their initial treatment (66%) compared to those receiving combination therapy (34%). During the 1‐year follow‐up after PAH diagnosis, 13% of patients increased their PAH medications while other patients either decreased their PAH medications (6%) or discontinued PAH treatment (27%). The 3‐ and 5‐year event‐free survival rates of all‐cause death were 72% and 64%, respectively. This is the first large‐scale administrative database study that provides insights into real‐world PAH management in Japan. This study highlighted a different PAH clinical landscape which included a larger portion of the elderly population, higher initial monotherapy treatment, and lower survival rates than previous studies