AbstractOpen systems with gain, loss, or both, described by non-Hermitian Hamiltonians, have been a research frontier for the past decade. In particular, such Hamiltonians which possess parity-time ($\mathcal{PT}$) symmetry feature dynamically stable regimes of unbroken symmetry with completely real eigenspectra that are rendered into complex conjugate pairs as the strength of the non-Hermiticity increases

We all learn in elementary quantum mechanics class that all measurable physical quantities, and specifically the Hamiltonian operator, must be Hermitian, because the eigenvalues must be real. This is perhaps von Neumann’s mathematical dogma, to which two main physical counterarguements exist.

AbstractThe neutron lifetime has been measured by comparing the decay rate with the reaction rate of $^3$He nuclei of a pulsed neutron beam from the spallation neutron source at the Japan Proton Accelerator Research Complex (J-PARC). The decay rate and the reaction rate were determined by simultaneously detecting electrons from the neutron decay and protons from the $^3$He(n,p)$^3$H reaction using

AbstractThe dynamical Casimir effect of the optomechanical cavity interacting with a one-dimensional photonic crystal is theoretically investigated in terms of complex spectral analysis of the Floquet–Liouvillian in the symplectic Floquet space. The quantum vacuum fluctuation of the intra-cavity mode is parametrically amplified by a periodic motion of the mirror boundary, and the amplified photons

We study the electromagnetic form factors of the lowest-lying singly heavy baryons in a pion mean-field approach, which is also known as the SU(3) chiral quark-soliton model. In the limit of the heavy-quark mass, the dynamics inside a singly heavy baryon is governed by the Nc-1 valence quarks, while the heavy quark remains as a static one. In this framework, a singly heavy baryon is described by combining

AbstractComputations of the primordial black hole (PBH) mass function discussed in the literature have conceptual issues. They stem from the fact that the mass function is a differential quantity and the standard criterion of the PBH formation from the seed primordial fluctuations cannot be directly applied to the computation of the differential quantities. We propose a new criterion of the PBH formation

AbstractA quantum scalar field inside the horizon of the non-rotating BTZ black hole is studied. Not only the near-horizon modes but also the normal modes deep inside the horizon are obtained. It is shown that the matching condition for the normal modes of a scalar field at the horizon does not uniquely determine the normal-mode expansion of a scalar field inside the horizon. By choosing a certain

AbstractGiven a Wilson action invariant under global chiral transformations, we can construct current composite operators in terms of the Wilson action. The short-distance singularities in the multiple products of the current operators are taken care of by the exact renormalization group. The Ward–Takahashi identity is compatible with the finite momentum cutoff of the Wilson action. The exact renormalization

AbstractThe emission of muonium ($\mu^+e^-$) atoms into vacuum from silica aerogel with laser ablation on its surface was studied with various ablation structures at room temperature using the subsurface muon beams at TRIUMF and Japan Proton Accelerator Research Complex (J-PARC). Laser ablation was applied to produce holes or grooves with typical dimensions of a few hundred $\mu$m to a few mm, except

Massive stars can explode as supernovae at the end of their life cycle, releasing neutrinos whose total energy reaches 1053erg. Moreover, neutrinos play key roles in supernovae, heating and reviving the shock wave as well as cooling the resulting proto-neutron star. Therefore, neutrino detectors are waiting to observe the next galactic supernova and several theoretical simulations of supernova neutrinos

AbstractWe have measured, for the first time, the inclusive missing-mass spectrum of the $^{12}$C$(K^-, p)$ reaction at an incident kaon momentum of 1.8 GeV/$c$ at the J-PARC K1.8 beamline. We observed a prominent quasi-elastic peak ($K^-p \rightarrow K^-p$) in this spectrum. In the quasi-elastic peak region, the effect of secondary interaction is apparently observed as a peak shift, and the peak exhibits

AbstractTo polarize neutrons with energy 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 $\varnothing15\times4 \, {\rm mm}^3$, allowing it to cover a wide beam diameter. It was operated in 0.35 T

In this paper, we review our non-Bloch band theory in 1D non-Hermitian tight-binding systems. In our theory, it is shown that in non-Hermitian systems, the Brillouin zone is determined so as to reproduce continuum energy bands in a large open chain. By using simple models, we explain the concept of the non-Bloch band theory and the method to calculate the Brillouin zone. In particular, for the non-Hermitian

AbstractThe complex scaling method (CSM) is one of the most powerful methods of describing the resonances with complex energy eigenstates based on non-Hermitian quantum mechanics. We present the basic application of CSM to the properties of the unbound phenomena of light nuclei. In particular, we focus on many-body resonant and non-resonant continuum states observed in unstable nuclei. We also investigate

AbstractBulk–boundary correspondence is the cornerstone of topological physics. In some non-Hermitian topological systems this fundamental relation is broken in the sense that the topological number calculated for the Bloch energy band under the periodic boundary condition fails to reproduce the boundary properties under the open boundary. To restore the bulk–boundary correspondence in such non-Hermitian

AbstractA 1D cluster model with next-nearest-neighbor interactions and two additional composite interactions is solved; the free energy is obtained and a correlation function is derived exactly. The model is diagonalized by a transformation obtained automatically from its interactions, which is an algebraic generalization of the Jordan–Wigner transformation. The gapless condition is expressed as a

AbstractWe investigate the inflationary expansion of the universe induced by higher-curvature corrections in M-theory. The inflationary evolution of the geometry is discussed in K. Hiraga and Y. Hyakutake, Prog. Theor. Exp. Phys. 2018, 113B03 (2018), which we follow to analyze metric perturbations around the background. We especially focus on scalar perturbations and analyze linearized equations of

AbstractWe 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

AbstractOne 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

AbstractSimilarly 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

AbstractWe 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.

AbstractThe idea of a hermetic quartz chamber in a dual-phase xenon time projection chamber (TPC) has the potential to improve the detector sensitivity for direct dark matter searches in the future. A major challenge facing TPC detectors in future dark matter experiments will be the reduction of the internal background such as $^{222}$Rn and the deterioration of the ionization signal due to electronegative

AbstractNon-Gaussianities of primordial perturbations in the soft limit provide important information about the light degrees of freedom during inflation. The soft modes of the curvature perturbations, unobservable for a local observer, act to rescale the spatial coordinates. We determine how the trispectrum in the collapsed limit is shifted by the rescaling due to the soft modes. We find that the

AbstractWe study three-dimensional $\mathcal{N}=2$ supersymmetric Chern—Simons matter theories on the direct product of a circle and a two-dimensional hemisphere ($S^1 \times {D^2}$) with specified boundary conditions by the method of localization. We construct boundary interactions to cancel the supersymmetric variation of the three-dimensional superpotential term and the Chern—Simons term and show

AbstractThe radioactive noble gas radon-222 ($\mathrm{^{222}Rn}$) produced in the uranium series is a crucial background source in many underground experiments. We have estimated the adsorption property of Rn with activated carbon fibers (ACFs) in air, argon, and xenon gas. We evaluated six ACFs, named A-7, A-10, A-15, A-20, A-25, and S-25, provided by Unitika Ltd. We measured the intrinsic radioactivity

AbstractWe discuss the physics of the three neutrino flavor transformation with non-unitary mixing matrix, with particular attention to the correlation between the $\nu$SM- and the $\alpha$ parameters which represent the effect of unitarity-violating (UV) new physics. Towards this goal, a new perturbative framework is created to illuminate the effect of non-unitarity in the region of the solar-scale

AbstractTo recognize sub-micron-range low-energy tracks recorded in a super-fine-grained nuclear emulsion (Nano Imaging Tracker), an elliptical fitting method was devised to analyze anisotropic images taken by an optical microscope. We report on this newly developed method using a discrete Fourier transform and second-order moment analysis of the brightness distribution. We succeeded in lowering the

We develop a strategy to determine the cosmic birefringence and miscalibrated polarization angles simultaneously using the observed |$EB$| polarization power spectra of the cosmic microwave background and the Galactic foreground emission. We extend the methodology of Y. Minami et al. (Prog. Theor. Exp. Phys. 2019, 083E02, 2019), which was developed for auto-frequency power spectra, by including cross-frequency

AbstractWe present evidence that recent numerical results from the reduced classical equations of the Lorentzian IIB matrix model can be interpreted as corresponding to the emergence of an expanding universe. In addition, we propose an effective metric to describe the emerging (3+1)D spacetime. This metric gives, at all times, finite values for the Ricci and Kretschmann curvature scalars. With these

AbstractWe compute an $s$-channel $2\to2$ scalar scattering $\phi\phi\to\Phi\to\phi\phi$ in the Gaussian wave-packet formalism at the tree level. We find that wave-packet effects, including shifts of the pole and the width of the propagator of $\Phi$, persist even when we do not take into account the time boundary effect for $2\to2$ proposed earlier. An interpretation of the result is that a heavy

AbstractWe analytically study the properties of the electromagnetic field in the vacuum around close binary compact stars containing at least one neutron star. We show that the orbital motion of the neutron star induces high multipole modes of the electromagnetic field just before the merger. These modes are superimposed to form a spiral arm configuration, and its edge is found to be a likely site

AbstractA dynamical aspect of quantum gravity on de Sitter spacetime is investigated by holography and the de Sitter/conformal field theory correspondence. We show that de Sitter spacetime emerges from a free Sp($N$) vector model by complexifying the ghost fields and course-graining them by flow equation in parallel to the imaginary axis. We confirm that the emergence of de Sitter spacetime is ensured

AbstractSince the theoretical prediction and experimental observation of the magnon thermal Hall effect, a variety of novel phenomena that may occur in magnonic systems have been proposed. We review recent advances in the study of topological phases of magnon Bogoliubov–de Gennes (BdG) systems. After giving an overview of previous works on electronic topological insulators and the magnon thermal Hall

AbstractIn this paper, we derive the relationship between the weak basis invariants (WB) related to CP violation responsible for leptogenesis and CP violation relevant at low energy. We examine all the experimentally viable cases of Frampton-Glashow and Yanagida (FGY) model, in order to construct the WB invariants in terms of left handed Majorana neutrino mass matrix elements, and thus finding the

AbstractIsotope shift of atomic spectra is considered as a probe of new interaction between electrons and neutrons in atoms. We employ the method of seeking a breakdown of King’s linearity in the isotope shifts of two atomic transitions. In the present work, we evaluate the magnitudes of the nonlinearity using relativistic wave functions and the result is compared with that of nonrelativistic wave

AbstractIn this article we discuss a construction of non-SUSY type II string vacua with the vanishing cosmological constant at the one-loop level based on the generic Gepner models for Calabi–Yau 3-folds. We make an orbifolding of the Gepner models by $\Bbb Z_2 \times \Bbb Z_4$, which asymmetrically acts with some discrete torsions incorporated. We demonstrate that the obtained type II string vacua

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

AbstractWe study the capability of generating the correct flavor neutrino mass matrix in a scalar clockwork model. First, we assume that the flavor structure is controlled by the Yukawa couplings as in the standard model. In this case, the correct flavor neutrino mass matrix could be obtained by appropriate Yukawa couplings $Y_{\ell^\prime\ell}$ where $\ell^\prime, \ell = e, \mu, \tau$. Next, we assume

AbstractRecently, the possibility of detecting gravitational wave echoes in the data stream subsequent to the binary black hole mergers observed by LIGO was suggested. Motivated by this suggestion, we presented templates of echoes based on black hole perturbations in our previous work. There, we assumed that the incident waves resulting in echoes are similar to the ones that directly escape to the

AbstractWe demonstrate that universal scaling behavior is observed in the current coronavirus (SARS-CoV-2) spread, the COVID-19 pandemic, in various countries. We analyze the numbers of infected people who tested positive (cases) in 11 selected countries (Japan, USA, Russia, Brazil, China, Italy, Indonesia, Spain, South Korea, UK, and Sweden). By using a double exponential function called the Gompertz

Observed well-developed |$\alpha$| cluster states in |$^{16}$|O located above the four-|$\alpha$| threshold are investigated from the viewpoint of Bose–Einstein condensation of |$\alpha$| 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

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 Cabibbo–Kobayashi–Maskawa 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

We have measured the differential cross-sections and analyzing powers for (⁠|$p,2p$|⁠) reactions at an incident energy of 392 MeV on |$^{12}$|C, |$^{16}$|O, |$^{40}$|Ca, and |$^{208}$|Pb 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

We apply a machine learning technique for identifying the topological charge of quantum gauge configurations in four-dimensional SU(3) Yang-Mills theory. The topological charge density measured on the original and smoothed gauge configurations with and without dimensional reduction is used for inputs of the neural networks (NN) with and without convolutional layers. The gradient flow is used for the

AbstractAnti-$\mathcal{PT}$ symmetry, $(\mathcal{PT})H=-H(\mathcal{PT})$, is a plausible variant of $\mathcal{PT}$ symmetry. Of particular interest is the situation when all the eigenstates of an anti-$\mathcal{PT}$-symmetric non-Hermitian Hamiltonian $H$ are also eigenstates of the $\mathcal{PT}$ operator; then, the quasi-energies are purely imaginary, which implies that the Hermitian conjugate $H^{+}=-H$

Chemical extraction using a molecular recognition resin named “Empore Radium Rad Disk” was developed to improve sensitivity for the low concentration of radium (Ra). Compared with the previous method, the extraction process speed was improved by a factor of three and the recovery rate for |$^{226}$|Ra was also improved from |$81\pm4\%$| to |$>99.9\%$|⁠. The sensitivity on the |$10^{-1}$| mBq level

The contribution to the muon anomalous magnetic moment from the fermion triangle loop diagrams connected to the muon line by a photon and a |$Z$| boson is re-analyzed in both the unitary gauge and the ’t Hooft–Feynman gauge. With use of the anomalous axial-vector Ward identity, it is shown that the calculation in the unitary gauge exactly coincides with the one in the ’t Hooft–Feynman gauge. The part

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 general covariance combined with the equivalence principle plays a 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

Using the hydrodynamical formalism of quantum mechanics for a Schrödinger spinning particle developed by Takabayashi, Vigier, and followers, which involves vortical flows, we propose a new geometrical interpretation of the pilot wave 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 a neutrino that forms an SU(2) doublet with a charged lepton. The lepton family number is defined through a weak basis of the 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

We present a model that gives a natural explanation to the charged lepton mass hierarchy and study the contributions to the electron and the muon |$g-2$|⁠. In the model, we introduce lepton-flavor-dependent |$U(1)_F$| symmetry and three additional Higgs doublets with |$U(1)_F$| charges, to realize that each generation of charged leptons couples to one of the three additional Higgs doublets. The |$U(1)_F$|

We re-examine the weak basis invariants at low energies proposed by C. Jarlskog and Branco et al. in their earlier analyses, after confronting them with the assumptions of two zeros and an equality between arbitrary non-zero elements in the Majorana neutrino mass matrix in the flavored basis. This particular conjecture is found to be experimentally feasible, as shown by S. Dev and D. Raj in their recent

Employing an all-to-all quark propagator technique, we investigate kaon–nucleon interactions in lattice QCD. We calculate the S-wave kaon–nucleon potentials at the leading order in the derivative expansion in the time-dependent HAL QCD method, using (2+1)-flavor gauge configurations on |$32^3 \times 64$| lattices with lattice spacing |$a \approx 0.09$| fm and pion mass |$m_{\pi} \approx 570$| MeV.

AbstractWe report our realization of a parity–time (PT)-symmetric non-Hermitian many-body system using cold atoms with dissipation. After developing a theoretical framework on PT-symmetric many-body systems using ultracold atoms in an optical lattice with controlled dissipation, we describe our experimental setup utilizing one-body atom loss as dissipation with special emphasis on calibration of important

We have investigated the status of the nuclear debris in the Unit-2 Nuclear Reactor of the Fukushima Daiichi Nuclear Power plant by the method called Cosmic Muon Radiography. In this measurement, the muon detector was placed outside of the reactor building as was the case of the measurement for the Unit-1 Reactor. Compared to the previous measurements, the detector was down-sized, which made us possible

In this paper, we study the quantum corrected thermodynamics of a class of black holes generated by self-gravitating Skyrmion models. One such black hole solution is Einstein-Skrymion black hole. We first compute the ADM mass of Einstein-Skyrmion black hole using on-shell Hamiltonian formalism present already in the literature. We then consider non-extended phase space thermodynamics and derive expressions

Masses and radii of neutron stars are obtained in the presence of strong magnetic fields together with rotation. Mass-radius relations are calculated using eleven EoSs (GM1, TM1-a, TM1-b, TM2ωρ-a, TM2ωρ-b, NL3-a, NL3-b, NL3ωρ-a, NL3ωρ-b, DDME2-a and DDME2-b) in relativistic mean field (RMF) theory. Obtained masses are over and around twice the solar mass (M⊙) for all EoSs in the presence of strong

We present additional observations to previous studies on the infrared (IR) renormalon in |$SU(N)$| QCD(adj.), the |$SU(N)$| gauge theory with |$n_W$|-flavor adjoint Weyl fermions on |$\mathbb{R}^3\times S^1$| with the |$\mathbb{Z}_N$| twisted boundary condition. First, we show that, for arbitrary finite |$N$|⁠, a logarithmic factor in the vacuum polarization of the “photon” (the gauge boson associated

The ratio of the partial widths of some dimension-5 proton decay modes can be predicted without detailed knowledge of supersymmetric (SUSY) particle masses, and this allows us to experimentally test various SUSY grand unified theory (GUT) models without discovering SUSY particles. In this paper, we study the ratio of the partial widths of the |$p\to K^0\mu^+$| and |$p\to K^+\bar{\nu}_\mu$| decays in