We designed, developed, and deployed a distributed sensor network aiming at observing high-energy ionizing radiation, primarily gamma rays, from winter thunderclouds and lightning in coastal areas of Japan. Starting in 2015, we have installed, in total, more than 15 units of ground-based detector system in Ishikawa Prefecture and Niigata Prefecture, and accumulated 551 days of observation time in four

Observed well-developed α cluster states in 16O located above the four α threshold are investigated from the viewpoint of Bose-Einstein condensation of α clusters by using a field-theoretical superfluid cluster model in which the order parameter is defined. The experimental energy levels are reproduced well for the first time by calculation. In particular, the observed 16.7 MeV 07+ and 18.8 MeV 08+

TianQin is a planned space-based gravitational wave (GW) observatory consisting of three earth orbiting satellites with an orbital radius of about 105 km. The satellites will form a equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs between 10-4 Hz and 1 Hz that can be generated by a wide variety of important astrophysical

An attempt has been made to carry out a detailed analysis of quark mass matrices having structure beyond the minimal texture. In particular, keeping in mind, precision measurements of CKM parameters as well as refinements in the ranges of light quark masses, we have examined the viability of all possible combinations of hermitian texture 5 zero quark mass matrices. Interestingly, one finds that all

We discuss physics of the three neutrino flavor transformation with non-unitary mixing matrix, with particular attention to the correlation between the νSM- and the α parameters which represent effect of unitarity violating (UV) new physics. Toward the goal, a new perturbative framework is created to illuminate the effect of non-unitarity in region of the solar-scale enhanced oscillations. We refute

A novel method of variation after |$K$|-projection is proposed to study dipole excitations in the framework of antisymmetrized molecular dynamics with the |$\beta$|-constraint. The method is applied to |$^{10}$|Be and |$^{16}$|O to describe low-energy dipole excitations. In the application to |${}^{10}\textrm{Be}$|⁠, two dipole states in the low-energy region are obtained. For |${}^{16}\textrm{O}$|⁠

We study, using the classical density functional theory (DFT), the fragility and short-time elastic constants of a soft-sphere liquid. For the amorphous state, the order parameter is the inhomogeneous density function |$\rho({\bf r})$| which is described in terms of Gaussian density profiles centered on a set random lattice points |$\{{\bf R}_i\}$|⁠. The latter is characterized in terms of the Bernel

The expansions of tree-level scattering amplitudes for one theory into amplitudes for another theory, which have been studied in recent work, exhibit hidden connections between different theories that are invisible in the traditional Lagrangian formulism of quantum field theory. In this paper, the general expansion of tree Einstein–Maxwell amplitudes into the Kleiss–Kuijf basis of tree Yang–Mills amplitudes

We investigate charged lepton flavor violating (CLFV) processes in the “neutrinophilic Higgs + seesaw model”, in which right-handed neutrinos couple only with an extra Higgs field which develops a tiny vacuum expectation value and the right-handed neutrinos also have Majorana mass. The model realizes a seesaw mechanism around TeV scale without extremely small Dirac Yukawa couplings. A phenomenological

Motivated by the investigation of a black hole’s properties in the lab, some interesting subjects such as analogue gravity and transformation optics are generated. In this paper, we look for analogies between the geometry of a gravitating system and the optical medium. In addition, we recognize that appropriate two-dimensional metamaterials can be used to mimic the propagation of light in the curved

Quantum electrodynamics predicts X-ray diffractions under a high-intensity laser field via virtual charged particles, and this phenomenon is called vacuum diffraction (VD). In this paper, we derive a new formula to describe VD in a head-on collision geometry of an X-ray free-electron laser (XFEL) pulse and a laser pulse. The wavefront curvature of the XFEL pulse is newly considered in this formula

The DC Josephson effect is the flow of supercurrent across a weak link between two superconductors with different values of their order parameters, the phase. We formulate this notion for any kind of spontaneous continuous symmetry breaking. The quantity that flows between the two systems is the zero-wavenumber Noether current associated with the broken symmetry. The AC Josephson effect is the oscillation

In the numerical analyses of the magnetic vortex with finite length, the boundary conditions are not properly imposed. In addition to Eqs. (4.7) and (4.8) in the original manuscript, the following condition has to be imposed [1–3]:

Topological phases and the associated multiple edge states are studied for parity and time-reversal (⁠|$\mathcal{PT}$|⁠)-symmetric non-Hermitian open quantum systems by constructing a non-unitary three-step quantum walk retaining |$\mathcal{PT}$| symmetry in one dimension. We show that the non-unitary quantum walk has large topological numbers of the |$\mathbb{Z}$| topological phase and numerically

Quasi-particles described by Green‘s functions of equilibrium systems exhibit non-Hermitian topological phenomena because of their finite lifetime. This non-Hermitian perspective on equilibrium systems provides new insights into correlated systems and attracts much interest because of its potential to solve open questions in correlated compounds. We provide a concise review of the non-Hermitian topological

We review the problem of Bogomol’nyi–Prasad–Sommerfield (BPS) state counting described by the generalized quiver matrix model of Atiyah–Drinfield–Hitchin–Manin type. In four dimensions the generating function of the counting gives the Nekrasov partition function, and we obtain a generalization in higher dimensions. By the localization theorem, the partition function is given by the sum of contributions

Taiji is a Chinese space mission to detect gravitational waves in the frequency band 0.1 mHz to 1.0 Hz, which aims at detecting super (intermediate) mass black hole mergers and extreme (intermediate) mass ratio in-spirals. A brief introduction of its mission overview, scientific objectives, and payload design is presented. A roadmap is also given in which the launching time is set to the 2030s.

One of interesting issues in two-dimensional superconformal field theories is the existence of anomalous modular transformation properties appearing in some non-compact superconformal models, corresponding to the “mock modularity” in mathematical literature. I review a series of my studies on this issue in collaboration with T. Eguchi, mainly focusing on T. Eguchi and Y. Sugawara, J. High Energy Phys

Similarly to the bosonic Liouville theory, the |$\mathcal{N}=2$| supersymmetric Liouville theory was conjectured to be equipped with the duality that exchanges the superpotential and the Kähler potential. The conjectured duality, however, seems to suffer from a mismatch of the preserved symmetries. More than fifteen years ago, when I was a student, my supervisor Tohru Eguchi gave a beautiful resolution

We briefly review some of the important developments in the last decade in the theory of multiple M2-branes and |$\text{AdS}_4/\text{CFT}_3$| correspondence. Taking the examples of the superconformal index, free energy on |$S^3$|⁠, and entropy of charged black holes, we illustrate how the large-|$N$| limit was studied and the correspondence was checked.

We have measured the differential cross sections and analyzing powers for (p, 2p) reactions at an incident energy of 392 MeV on 12C, 16O, 40Ca, and 208Pb nuclei, leading to discrete states of the residual nuclei. The data are compared with two kinds of distorted-wave impulse approximation (DWIA) calculations, a standard calculation using a global optical potential and a calculation using wave functions

We define a proper effective temperature for relativistic nonequilibrium steady states (NESSs). A conventional effective temperature of NESSs is defined from the ratio of the fluctuation to the dissipation. However, NESSs have relative velocities to the heat bath in general, and hence the conventional effective temperature can be frame dependent in relativistic systems. The proper effective temperature

Gravity theory based on current algebra is formulated. The gauge principle rather than the general covariance combined with the equivalence principle plays the pivotal role in the formalism, and the latter principles are derived as a consequence of the theory. In this approach, it turns out that gauging the Poincaré algebra is not appropriate but gauging the SO(N, M) algebra gives a consistent theory

For the polarization of neutrons with an energy of beyond 0.1 eV, we developed a novel polarized proton spin filter based on dynamic nuclear polarization using photo-excited triplet electron spins. The spin filter consists of a single crystal of naphthalene doped with deuterated pentacene and has a size of ϕ15 × 4 mm3, allowing it to cover a wide beam diameter. It was operated in 0.35 T and at 90 K

Using the hydrodynamical formalism of quantum mechanics for a Schrödinger spinning particle, developed by T. Takabayashi, J. P. Vigier and followers, that involves vortical flows, we propose the new geometrical interpretation of the wave-pilot theory. The spinor wave in this interpretation represents an objectively real field and the evolution of a material particle controlled by the wave is a manifestation

We study the time evolution of lepton family number for neutrino which forms SU(2) doublet with charged lepton. The lepton family number is defined through a weak basis of SU(2) doublet in which the charged lepton mass matrix is a real and diagonal one. The lepton family number carried by the neutrino is defined with a left-handed current of the neutrino family. We study the time evolution of the lepton

We investigate the HAL QCD potential in |$I=1$||$\pi \pi$| scattering using the hybrid method for all-to-all propagators, in which a propagator is approximated by low eigenmodes, and the remaining high-eigenmode part is stochastically estimated. To verify the applicability of the hybrid method to systems containing quark creation|$/$|annihilation contributions such as the |$\rho$| meson, we calculate

Leibniz algebras |${\mathcal E}_n$| were introduced as an algebraic structure underlying U-duality. Algebras |${\mathcal E}_3$| derived from Bianchi 3D Lie algebras are classified here. Two types of algebras are obtained: 6D Lie algebras that can be considered an extension of the semi-Abelian 4D Drinfel’d double and unique extensions of non-Abelian Bianchi algebras. For all of the algebras explicit

Recently a matrix model with non-pairwise index contractions has been studied in the context of the canonical tensor model, a tensor model for quantum gravity in the canonical formalism. This matrix model also appears in the same form with different ranges of parameters and variables, when the replica trick is applied to the spherical |$p$|-spin model (⁠|$p=3$|⁠) in spin glass theory. Previous studies

We investigate some properties of the standard rotator approximation of the |$\mathrm{SU}(N)\times\mathrm{SU}(N)$| sigma-model in the delta regime. In particular, we show that the isospin susceptibility calculated in this framework agrees with that computed by chiral perturbation theory up to next-to-next-to-leading order in the limit |$\ell=L_t/L\to\infty$|⁠. The difference between the results involves

In double field theory, the physical space has been understood as a subspace of the doubled space. Recently, the doubled space has been defined as the para-Hermitian manifold and the physical space is realized as a leaf of a foliation of the doubled space. This construction naturally introduces the fundamental 2-form, which plays an important role in a reformulation of string theory known as the Born

We study the time evolution of mutual information (MI) and logarithmic negativity (LN) in two-dimensional free scalar theory with two kinds of time-dependent masses: one time evolves continuously from non-zero mass to zero; the other time evolves continuously from finite mass to finite mass, but becomes massless once during the time evolution. We call the former protocol ECP, and the latter protocol

In a system consisting of a monolayer ferromagnetic graphene structure, based on the scattering matrix approach, we study the spin-dependent transmission coefficients, group delay time, magnetoresistance and giant magnetoresistance of spin-polarized electron tunneling through the Rashba barrier in single-layer graphene. The results show that Rashba spin–orbit coupling can cause a natural spin filter

Resonance states of axion-like particles were searched for via four-wave mixing by focusing two-color pulsed lasers into a quasi-vacuum. A quasi-parallel collision system that allows probing of the sub-eV mass range was realized by focusing the combined laser fields with an off-axis parabolic mirror. A 0.10 mJ/34 fs Ti:sapphire laser pulse and a 0.14 mJ/9 ns Nd:YAG laser pulse were spatiotemporally

The |$T$|-duality of string theory can be extended to the Poisson–Lie |$T$|-duality when the target space has a generalized isometry group given by a Drinfel’d double. In M-theory, |$T$|-duality is understood as a subgroup of |$U$|-duality, but the non-Abelian extension of |$U$|-duality is still a mystery. In this paper we study membrane theory on a curved background with a generalized isometry group

|$T$|- and |$S$|-duality rules among the gauge potentials in type II supergravities are studied. In particular, by following the approach of [J. J. Fernández-Melgarejo et al., arXiv:1909.01335], we determine the |$T$|- and |$S$|-duality rules for certain mixed-symmetry potentials, which couple to supersymmetric branes with tension |$T\propto g_s^{-n}$| (⁠|$n\leq 4$|⁠). Although the |$T$|-duality rules

We investigate the possible occurrence of highly elongated shapes near the yrast line in |$^{40}$|Ca and |$^{41}$|Ca at high spins on the basis of the nuclear energy-density functional method. Both the superdeformed (SD) yrast configuration and the yrare configurations on top of the SD band are described by solving the cranked Skyme–Kohn–Sham equation in the three-dimensional coordinate space representation

In this paper, we study the vortex motion of a continuous medium, which is described by forces obtained from the principle of least action. It is shown that in a continuous medium the vortex force components are proportional to the velocity and pressure gradient components. This article gives a description of the 2D vortex motion of air in zones of high and low pressure. If the pressure decreases,

We investigate theoretically the |$K^{0} p$| invariant mass spectrum of the |$K^{+} d \to K^{0} p p$| reaction and scrutinize how the signal of the “|$\Theta ^{+}$|” pentaquark, if it exists, emerges in the |$K^{0} p$| spectrum. The most prominent advantage of this reaction is that we can clearly assess whether the “|$\Theta ^{+}$|” exists or not as a direct-formation production without significant

We reexamine two-dimensional Lorentzian conformal field theory using the formalism previously developed in a study of sine-square deformation of Euclidean conformal field theory. We construct three types of Virasoro algebra. One of them reproduces the result by Lüscher and Mack, while another type exhibits divergence in the central charge term. The third leads to a continuous spectrum and contains

We discuss the analytical expression of the oscillation probabilities at low energy long baseline experiments, such as Tokai to HyperKamiokande (T2HK) and Tokai to HyperKamioka and Korea (T2HKK), in the presence of nonstandard interactions (NSIs). We show that these experiments are advantageous in the exploration of the NSI parameters (⁠|$\epsilon_D$|⁠, |$\epsilon_N$|⁠), which were suggested to be

We investigate double |$\Lambda$| hyperfragment formation from the statistical decay of double |$\Lambda$| compound nuclei produced in the |$\Xi^-$| absorption at rest in the light nuclei |$^{12}\mathrm{C}$|⁠, |$^{14}\mathrm{N}$|⁠, and |$^{16}\mathrm{O}$|⁠. We examine the target and the |$\Lambda\Lambda$| bond energy dependence of the double |$\Lambda$| hyperfragment formation probabilities, especially

We investigate solitons in the Peyrard–Bishop model of a DNA molecule using Renormalization Group methods which provide a systematic way for perturbation analysis. Small amplitude expansion is carried out in both the continuous and discrete limits. We review exact solutions for the continuous model. Further, we discuss the reliability of the solitonic solutions and argue that the envelope should propagate

We investigate measurement theory in classical mechanics in the formulation of classical mechanics by Koopman and von Neumann (KvN), which uses Hilbert space. We show a difference between classical and quantum mechanics in the “relative interpretation” of the state of the target of measurement and the state of the measurement device. We also derive the uncertainty relation in classical mechanics.

Induced Compton scattering (ICS) is a nonlinear interaction between intense electromagnetic radiation and a rarefied plasma. Although the magnetosphere of pulsars is a potential site at which ICS occurs in nature, ICS signatures have not been discovered so far. One of the reasons for the non-detection of ICS signatures is that we still do not possess a concrete understanding of such nonlinear plasma

We formulate a perturbative framework for the flavor transformation of the standard active three neutrinos but with a non-unitary flavor mixing matrix, a system which may be relevant for the leptonic unitarity test. We use the |$\alpha$| parametrization of the non-unitary matrix and take its elements |$\alpha_{\beta \gamma}$| (⁠|$\beta,\gamma = e,\mu,\tau$|⁠) and the ratio |$\epsilon \simeq \Delta

By employing the |$1/N$| expansion, we compute the vacuum energy |$E(\delta\epsilon)$| of the two-dimensional supersymmetric (SUSY) |$\mathbb{C}P^{N-1}$| model on |$\mathbb{R}\times S^1$| with |$\mathbb{Z}_N$| twisted boundary conditions to the second order in a SUSY-breaking parameter |$\delta\epsilon$|⁠. This quantity was vigorously studied recently by Fujimori et al. using a semi-classical approximation

We study the discrete Darboux transformation and construct multi-soliton solutions in terms of the ratio of determinants for the integrable discrete sine-Gordon equation. We also calculate explicit expressions of single-, double-, triple-, and quadruple-soliton solutions as well as single- and double-breather solutions of the discrete sine-Gordon equation. The dynamical features of discrete kinks and

We study a strategy to determine miscalibrated polarization angles of cosmic microwave background (CMB) experiments using the observed |$EB$| polarization power spectra of CMB and Galactic foreground emission. We apply the methodology of Y. Minami et al. (Prog. Theor. Exp. Phys. 2019, 083E02, 2019), developed for full-sky observations to ground-based experiments such as Simons Observatory. We take

In this paper, we study rare semileptonic decays of the |$B_c$| meson in the context of type-I, II, and III two Higgs doublet models. We follow the relativistic quark model for parameterizing the form factors used in matrix elements of weak transitions between the corresponding meson states. We investigate observables such as branching ratio, lepton polarization asymmetry, forward–backward asymmetry

We apply independent component analysis (ICA) to real data from a gravitational wave detector for the first time. Specifically, we use the iKAGRA data taken in April 2016, and calculate the correlations between the gravitational wave strain channel and 35 physical environmental channels. Using a couple of seismic channels which are found to be strongly correlated with the strain, we perform ICA. Injecting

We investigate the shear viscosity of massless classical scalar fields in the |$\phi^4$| theory on a lattice by using the Green–Kubo formula. Based on the scaling property of the classical field, the shear viscosity is represented using a scaling function. The equilibrium expectation value of the time-correlation function of the energy–momentum tensor is evaluated as the ensemble average of the classical

Chiral symmetry restoration of quarks is investigated at finite density in quantum chromodynamics. The critical chemical potentials at zero temperature, in which the chiral symmetry is restored, are calculated with the Schwinger-Dyson equation in the real-time formalism without the instantaneous exchange approximation. We present some properties of the quark mass functions and the quark propagators

In this paper, new analytic formulas for one-loop contributing to Higgs decay channel |$H \rightarrow Z\gamma$| are presented in terms of hypergeometric functions. The calculations are performed by following the technique for tensor one-loop reduction developed in [A. I. Davydychev, Phys. Lett. B 263 (1991) 107]. For the first time, one-loop form factors for the decay process are shown which are valid

We propose a novel mechanism to reproduce the observed mass hierarchy for scalar mesons lighter than 1 GeV (called the inverse hierarchy), regarding them as mesons made of a quark and an anti-quark (⁠|$q\bar{q}$| mesons). The source is provided by the SU(3) flavor-symmetry breaking induced by the U(1) axial anomaly. In particular, the anomaly term including the explicit chiral symmetry breaking plays

We present a flavor model with |$S_3$| modular invariance in the framework of SU(5) grand unified theory (GUT). The |$S_3$| modular forms of weights |$2$| and |$4$| give the quark and lepton mass matrices with a common complex parameter, the modulus |$\tau$|⁠. The GUT relation of down-type quarks and charged leptons is imposed by the vacuum expectation value (VEV) of the adjoint 24-dimensional Higgs

We analyze excited baryon states using a holographic dual of quantum chromodynamics that is defined on the basis of an intersecting D4/D8-brane system. Studies of baryons in this model have been made by regarding them as a topological soliton of a gauge theory on a five-dimensional curved spacetime. However, this allows one to obtain only a certain class of baryons. We attempt to present a framework

Type II string theory or M-theory contains a broad spectrum of gauge potentials. In addition to the standard |$p$|-form potentials, various mixed-symmetry potentials have been predicted, which may couple to exotic branes with non-standard tensions. Together with |$p$|-forms, mixed-symmetry potentials turn out to be essential to build the multiplets of the |$U$|-duality symmetry in each dimension. In

A dynamically transversely trapping surface (DTTS) is a new concept for an extension of a photon sphere that appropriately represents a strong gravity region and has close analogy with a trapped surface. We study formation of a marginally DTTS in time-symmetric, conformally flat initial data with two black holes, with a spindle-shaped source, and with a ring-shaped source, and clarify that |$\mathcal{C}\lesssim

In |$U$|-duality-manifest formulations, supergravity fields are packaged into covariant objects such as the generalized metric and |$p$|-form fields |$\mathcal A_p^{I_p}$|⁠. While a parameterization of the generalized metric in terms of supergravity fields is known for |$U$|-duality groups |$E_n$| with |$n\leq 8$|⁠, a parameterization of |$\mathcal A_p^{I_p}$| has not been fully determined. In this