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The strength distributions of the Isoscalar Giant Monopole Resonance (ISGMR) and Isoscalar Giant Quadrupole Resonance (ISGQR) in 142,146-150Nd have been determined via inelastic alpha-particle scattering with the Grand Raiden (GR) Spectrometer at the Research Center for Nuclear Physics (RCNP), Japan. In the deformed nuclei 146-150Nd, the ISGMR strength distributions exhibit a splitting into two components, while the nearly spherical nucleus 142Nd displays a single peak in the ISGMR strength distribution. A noteworthy achievement in this study is the first-time detection of overtones in the Isoscalar Giant Quadrupole Resonance (ISGQR) strength distributions within Nd isotopes at an excitation energy around 25 MeV obtained through Multipole Decomposition Analysis (MDA)., Comment: Accepted for publication in Physics Letters B

In this review, I present the electronic properties of the beta-pyrochlore oxide CsW2O6 and other related materials. At 215 K, CsW2O6 exhibits an electronic phase transition to a nonmagnetic insulating state, which exhibits a complex self-organization of 5d electrons. In this phase transition, various factors, such as geometrical frustration of the pyrochlore structure, moderately strong electron correlation, Jahn-Teller-like distortion, phase transition to the insulating state, and formation of chemical bonds in solids, which are powerful driving forces for achieving a wide variety of electronic properties in transition metal oxides, play important roles. In CsW2O6, the interplay of these factors has led to the emergence of an electronic phase transition that preserves the cubic symmetry, three-dimensional nesting of Fermi surfaces, a possible charge order with a fractional valence satisfying the Anderson condition, and an equilateral-triangular trimer formation by a three-centered-two-electron bond. In addition to the introduction of these unique features of CsW2O6, each of them has been compared to those of other materials to provide an overview of the electronic properties of a wide variety of related materials, which can contribute to a complete understanding of the vast and infinite electronic phenomena in transition metal oxides., Comment: 19 pages, 22 figures

Various noncollinear spin textures and magnetic phases have been predicted in twisted two-dimensional CrI$_3$ due to competing ferromagnetic (FM) and antiferromagnetic (AFM) interlayer exchange from moir\'e stacking - with potential spintronic applications even when the underlying material possesses a negligible Dzyaloshinskii-Moriya or dipole-dipole interaction. Recent measurements have shown evidence of coexisting FM and AFM layer order in small-twist-angle CrI$_3$ bilayers and double bilayers. Yet, the nature of the magnetic textures remains unresolved and possibilities for their manipulation and electrical readout are unexplored. Here, we use tunneling magnetoresistance to investigate the collective spin states of twisted double-bilayer CrI$_3$ under both out-of-plane and in-plane magnetic fields together with detailed micromagnetic simulations of domain dynamics based on magnetic circular dichroism. Our results capture hysteretic and anisotropic field evolutions of the magnetic states and we further uncover two distinct non-volatile spin textures (out-of-plane and in-plane domains) at $\approx$ 1{\deg} twist angle, with a different global tunneling resistance that can be switched by magnetic field., Comment: 18 pages, 5 figures

We have investigated the redshift evolution of the relationship between supermassive black hole (SMBH) mass and host bulge mass using a semi-analytical galaxy formation model $\nu^2$GC. Our model reproduces the relation in the local universe well. We find that, at high redshift ($z \gtrsim 3$), two sequences appear in the SMBH mass--bulge mass plane. The emergence of these two sequences can be attributed to the primary triggers of the growth of the SMBHs and bulges: galaxy mergers and disc instabilities. The growth of SMBHs and bulges as a result of galaxy mergers is responsible for giving rise to the high-mass sequence, in which SMBHs are more massive for a given host bulge mass than in the low-mas sequence. Conversely, disc instabilities are accountable for the emergence of the low-mass sequence. At lower redshifts, galaxy mergers tend to become increasingly deficient in gas, resulting in a preferential increase of bulge mass without a corresponding growth in SMBH mass. This has the effect of causing galaxies in the upper sequence to shift towards the lower one on the SMBH mass-bulge mass plane. The galaxies that undergo dry mergers serve to bridge the gap between the two sequences, eventually leading to convergence into a single relation known in the local universe. Our results suggest that the observations of the SMBH mass-bulge mass relation in high redshifts can provide insight into their growth mechanisms., Comment: 7 pages, 7 figure, accepted for publication in MNRAS

We searched for the 6$\alpha$-condensed state in $^{24}$Mg by measuring the $^{12}\rm{C}+{}^{12}\rm{C}$ scattering with the SAKRA Si detector array at $E_\rm{cm}$ = 17.5-25.0 MeV. By using the invariant-mass method for the detected 3$\alpha$ particles, the inclusive cross sections for the $^{12}\rm{C}+{}^{12}\rm{C}\to{}^{12}\rm{C}(0^+_2)+X$ and $^{12}\rm{C}(3^-_1)+X$ reactions were determined. In addition, the missing-mass spectroscopy was successfully utilized to determine the excitation energy of the residual $^{12}\rm{C}$ nucleus and the exclusive cross sections for the $^{12}\rm{C}+{}^{12}\rm{C}\to{}^{12}\rm{C}(0^+_2)+{}^{12}\rm{C}(0^+_1)$, $^{12}\rm{C}(0^+_2)+{}^{12}\rm{C}(2^+_1)$, and $^{12}\rm{C}(0^+_2)+{}^{12}\rm{C}(0^+_2)$ reactions. In both the inclusive $^{12}\rm{C}(0^+_2)+X$ channel and the exclusive $^{12}\rm{C}(0^+_2)+{}^{12}\rm{C}(0^+_1)$ channel, the cross section peaked at $E_rm{cm}$ = 19.4 MeV, which correspond to the excitation energy of $E_x$ = 33.3 MeV in $^{24}\rm{Mg}$. This 19.4-MeV state is a candidate for the 6$\alpha$-condensed state because of the agreement of the excitation energy with the theoretical value and its decay property. In the exclusive $^{12}\rm{C}(0^+_2)+{}^{12}\rm{C}(0^+_2)$ channel, a broad state was observed at $E_\rm{cm}$ = 22.5 MeV, which correspond to the excitation energy of $E_x$ = 36.4 MeV in $^{24}\rm{Mg}$. From the angular distribution of the differential cross section, the spin and parity of this 22.5-MeV state was assigned to be $4^+$. In addition, a $2^+$ state was suggested at the low-energy side of the 22.5-MeV state. Because their excitation energies are higher than the theoretical value of the 6$\alpha$-condensed state, these states might be excited states of the 6$\alpha$-condensed state such as the $2^+_2$ and $4^+_1$ states in $^{12}\rm{C}$., Comment: 8 pages, 6 figures

The electronic properties of ScPdGe and ScPdSi, crystallizing in the hexagonal ZrNiAl and orthorhombic TiNiSi structures, respectively, are investigated. ScPdGe and ScPdSi are found to show bulk superconductivity below 0.9 and 1.7 K, respectively, based on electrical resistivity and heat capacity data measured using synthesized polycrystalline samples. First principles calculations indicate the presence of large contributions of Sc 3d and Pd 4d electrons at the Fermi energy in both materials. The electronic properties and electronic states of these materials are discussed in comparison with those of several superconductors containing scandium and a 4d transition metal element., Comment: 5 pages, 4 figures, accepted for publication in J. Phys. Soc. Jpn

Matrix factorization (MF) is a simple collaborative filtering technique that achieves superior recommendation accuracy by decomposing the user-item interaction matrix into user and item latent matrices. Because the model typically learns each interaction independently, it may overlook the underlying shared dependencies between users and items, resulting in less stable and interpretable recommendations. Based on these insights, we propose "Hierarchical Matrix Factorization" (HMF), which incorporates clustering concepts to capture the hierarchy, where leaf nodes and other nodes correspond to users/items and clusters, respectively. Central to our approach, called hierarchical embeddings, is the additional decomposition of the latent matrices (embeddings) into probabilistic connection matrices, which link the hierarchy, and a root cluster latent matrix. The embeddings are differentiable, allowing simultaneous learning of interactions and clustering using a single gradient descent method. Furthermore, the obtained cluster-specific interactions naturally summarize user-item interactions and provide interpretability. Experimental results on ratings and ranking predictions show that HMF outperforms existing MF methods, in particular achieving a 1.37 point improvement in RMSE for sparse interactions. Additionally, it was confirmed that the clustering integration of HMF has the potential for faster learning convergence and mitigation of overfitting compared to MF, and also provides interpretability through a cluster-centered case study.

Cloud-cloud collisions (CCCs) are expected to compress gas and trigger star formation. However, it is not well understood how the collisions and the induced star formation affect galactic-scale properties. By developing an on-the-fly algorithm to identify CCCs at each timestep in a galaxy simulation and a model that relates CCC-triggered star formation to collision speeds, we perform simulations of isolated galaxies to study the evolution of galaxies and giant molecular clouds (GMCs) with prescriptions of self-consistent CCC-driven star formation and stellar feedback. We find that the simulation with the CCC-triggered star formation produces slightly higher star formation rates and a steeper Kennicutt-Schmidt relation than that with a more standard star formation recipe, although collision speeds and frequencies are insensitive to the star formation models. In the simulation with the CCC model, about 70 per cent of the stars are born via CCCs, and colliding GMCs with masses of $\approx 10^{5.5}\,M_{\odot}$ are the main drivers of CCC-driven star formation. In the simulation with the standard star formation recipe, about 50 per cent of stars are born in colliding GMCs even without the CCC-triggered star formation model. These results suggest that CCCs may be one of the most important star formation processes in galaxy evolution. Furthermore, we find that a post-processing analysis of CCCs, as used in previous studies in galaxy simulations, may lead to slightly greater collision speeds and significantly lower collision frequencies than the on-the-fly analysis., Comment: 18 pages, 16 figures, published in MNRAS

Structural fluctuations and dynamic cross-correlations in the mouse eugenol olfactory receptor (Olfr73) were studied by molecular dynamics (MD) simulation to characterize the dynamic response of the protein upon ligand binding. The initial structure was generated by the artificial intelligence tool AlfaFold2 due to the current lack of experimental data. We focused on the hydrogen (H) bond of the odorant eugenol to Ser113, Asn207, and Tyr260 of the receptor protein, the importance of which has been suggested by previous experimental studies. The H-bond was not observed in docking simulations, but in subsequent MD simulations the H-bond to Ser113 was formed in 2--4 ns. The lifetime of the H-bond was in the range of 1--20 ns. On the trajectory with the most stable (20 ns) H-bond, the structural fluctuation of the $\alpha$-carbon atoms of the receptor main chain was studied by calculating the root mean square fluctuations, the dynamic cross-correlation map, and the time-dependent dynamic cross-correlation. The analysis suggested a correlation transfer pathway Ser113 $\to$ Phe182 $\to$ (Leu259 or Tyr260) $\to$ Tyr291 induced by the ligand binding with a time scale of 4--6 ns., Comment: 6 pages, 8 figures