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Tomography of a displacement photon counter for discrimination of single-rail optical qubitsNov 21 2017Apr 18 2018We investigate the performance of a Kennedy receiver, which is known as a beneficial tool in optical coherent communications, to the quantum state discrimination of the two superpositions of vacuum and single photon states corresponding to the $\hat\sigma_x$ ... More

Distributed quantum sensing in a continuous variable entangled networkMay 23 2019Networking plays a ubiquitous role in quantum technology. It is an integral part of quantum communication and has significant potential for upscaling quantum computer technologies that are otherwise not scalable. Recently, it was realized that sensing ... More

Quantum receivers with squeezing and photon-number-resolving detectorsFeb 12 2013Apr 16 2013We propose quantum receivers with optical squeezing and photon-number-resolving detector (PNRD) for the near-optimal discrimination of quaternary phase-shift-keyed coherent state signals. The basic scheme is similar to the previous proposals (e.g. Phys. ... More

Projective measurement onto arbitrary superposition of coherent state basesFeb 21 2017Feb 15 2018One of the peculiar features in quantum mechanics is that a superposition of macroscopically distinct states can exits. In optical system, this is highlighted by a superposition of coherent states (SCS), i.e. a superposition of classical states. Recently ... More

Fundamental precision limit of a Mach-Zehnder interferometric sensor when one of the inputs is the vacuumMay 26 2017In the lore of quantum metrology, one often hears (or reads) the following no-go theorem: If you put vacuum into one input port of a balanced Mach-Zehnder Interferometer, then no matter what you put into the other input port, and no matter what your detection ... More

A molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 at 3 mm with the Nobeyama 45 m radio telescope: The dataFeb 28 2019We present observational data of a molecular line survey toward the nearby galaxies NGC 1068, NGC 253, and IC 342 at the wavelengths of 3 mm ($\sim$85--116 GHz) obtained with the Nobeyama 45 m radio telescope. In IC 342 the line survey with high spectral ... More

Displacement receiver for phase-shift-keyed coherent statesAug 09 2012Quantum receiver is an important tool for overcoming the standard quantum limit (SQL) of discrimination errors in optical communication. We theoretically study the quantum receivers for discriminating ternary and quaternary phase shift keyed coherent ... More

Optical phase estimation via coherent state and displaced photon countingApr 15 2016Jun 21 2016We consider the phase sensing via weak optical coherent state at quantum limit precision. A new detection scheme for the phase estimation is proposed which is inspired by the suboptimal quantum measurement in coherent optical communication. We theoretically ... More

The flow of weights and the Cuntz-Pimsner algebrasAug 25 2016We describe the flows of weights for von Neumann algebras arising from KMS states for the gauge actions of the Cuntz-Pimsner algebras in terms of Poisson (tail) boundaries.

The classification of $3^n$ subfactors and related fusion categoriesSep 24 2016Oct 06 2016We investigate a (potentially infinite) series of subfactors, called $3^n$ subfactors, including $A_4$, $A_7$, and the Haagerup subfactor as the first three members corresponding to $n=1,2,3$. Generalizing our previous work for odd $n$, we further develop ... More

A Cuntz algebra approach to the classification of near-group categoriesDec 14 2015Dec 30 2015We classify C$^*$ near-group categories by using Vaughan Jones theory of subfactors and the Cuntz algebra endomorphisms. Our results show that there is a sharp contrast between two essentially different cases, integral and irrational cases. When the dimension ... More

Geometric structures of late points of a two-dimensional simple random walkMay 04 2016We consider the problem, as suggested by Dembo ($2003$, $2006$), of late points of a simple random walk in two dimensions. It has been shown that the exponents for the numbers of pairs of late points coincide with those of nearly favorite points and high ... More

Improving Lower Bound on Opaque Set for Equilateral TriangleSep 13 2015An opaque set (or a barrier) for $U \subseteq \mathbb{R}^2$ is a set $B$ of finite-length curves such that any line intersecting $U$ also intersects $B$. In this paper, we consider the lower bound for the shortest barrier when $U$ is the unit equilateral ... More

Sufficiency of simplex inequalitiesSep 18 2013Feb 11 2015Let z_0,...,z_n be the (n-1)-dimensional volumes of facets of an n-simplex. Then we have the simplex inequalities: z_p < z_0+...+\check{z}_p+...+z_n (0 =< p =< n), generalizations of triangle inequalities. Conversely, suppose that numbers z_0,...,z_n ... More

Spaces of polynomial functions of bounded degrees on an embedded manifold and their dualsFeb 14 2011Feb 11 2015Let $\mathcal{O}(U)$ denote the algebra of holomorphic functions on an open subset $U\subset\mathbb{C}^n$ and $Z\subset\mathcal{O}(U)$ its finite-dimensional vector subspace. By the theory of least space of de Boor and Ron, there exists a projection $T_b$ ... More

The classification of $3^n$ subfactors and related fusion categoriesSep 24 2016We investigate a (potentially infinite) series of subfactors, called $3^n$ subfactors, including $A_4$, $A_7$, and the Haagerup subfactor as the first three members corresponding to $n=1,2,3$. Generalizing our previous work for odd $n$, we further develop ... More

Causal Structures in Gauss-Bonnet gravityJun 03 2014Sep 03 2014We analyze causal structures in Gauss-Bonnet gravity. It is known that Gauss-Bonnet gravity potentially has superluminal propagation of gravitons due to its noncanonical kinetic terms. In a theory with superluminal modes, an analysis of causality based ... More

Inclusions of simple $C^*$-algebrasJun 13 2001We prove that if a conditional expectation from a simple $C^*$-algebra onto its $C^*$-subalgebra satisfies the Pimsner-Popa inequality, there exists a quasi-basis. As an application, we establish the Galois correspondence for outer actions of finite groups ... More

Space(-Time) Emergence as Symmetry Breaking EffectFeb 04 2011The microscopic origin of space(-time) geometry is explained on the basis of an emergence process associated with the condensation of infinite number of microscopic quanta responsible for symmetry breakdown, which implements the basic essence of "Quantum-Classical ... More

Perspective from Micro-Macro Duality -- Towards non-perturbative renormalization schemeFeb 08 2011The problem of renormalization procedure is re-examined from the viewpoint of Micro-Macro duality.

Roles of Asymptotic Condition and S-Matrix as Micro-Macro Duality in QFTFeb 08 2011Various versions of "independence" are actively inverstigated in quantum probability. In the context of relativistic QFT, we show here that the physical origin of "independence" can be sought in the asymptotic condition through which asymptotic fields ... More

Exponents for the number of pairs of nearly favorite points of simple random walk in ${\mathbb Z}^2$Feb 18 2016We consider the problem on nearly favorite points of simple random walk in $\mathbb{Z}^2$ which Dembo et al. suggested. We determine the power exponents for the numbers of pairs of $\alpha$-favorite points. These are conjectured to coincide with the exponents ... More

The inner boundary of random walk rangeJul 08 2014Dec 23 2014In this paper, we deal with the inner boundary of random walk range, that is, the set of those points in a random walk range which have at least one neighbor site outside the range. If $L_n$ be the number of the inner boundary points of random walk range ... More

Frequently visited sites of the inner boundary of simple random walk rangeSep 30 2014Feb 18 2016This paper considers the question: how many times does a simple random walk revisit the most frequently visited site among the inner boundary points? It is known that in ${\mathbb{Z}}^2$, the number of visits to the most frequently visited site among ... More

How to Formulate Non-Equilibrium Local States in QFT? --General Characterization and Extension to Curved Spacetime--Feb 14 2003The essence of a general formulation to accommodate non-equilibrium local states in relativistic quantum field theory is explained from the viewpoint of comparison at a spacetime point between unknown generic states to be characterized as such states ... More

A Simple Derivation of Josephson Formulae in SuperconductivityDec 15 1999Dec 20 1999A simple and general derivation of Josephson formulae for the tunneling currents is presented on the basis of Sewell's general formulation of superconductivity in use of off-diagonal long range order (ODLRO).

A Unified Scheme for Generalized Sectors based on Selection Criteria --Order parameters of symmetries and of thermality and physical meanings of adjunctions--Mar 04 2003A unified scheme for treating generalized superselection sectors is proposed on the basis of the notion of selection criteria to characterize states of relevance to each specific domain in quantum physics, ranging from the relativistic quantum fields ... More

A perturbation problem for the shift semigroupFeb 15 2007Motivated by B. Tsirelson's construction of $E_0$-semigroups of type III, we investigate a $C_0$-semigroup acting on the space of square integrable functions of the half line whose difference from the shift semigroup is a Hilbert-Schmidt operator. We ... More

$E_0$-semigroups: around and beyond Arveson's workSep 26 2012We give an account of the theory of $E_0$-semigroups. We first focus on Arveson's contributions to the field and related results. Then we present the recent development of type II and type III $E_0$-semigroups. We also include a short note in Appendix, ... More

Temparature as Order Parameter of Broken Scale InvarianceNov 16 2003In algebraic quantum field theory the (inverse) temperature is shown to be a macroscopic \textit{order parameter} to parametrize mutually disjoint thermal \textit{sectors} arising from the \textit{broken scale invariance} under renormalization-group transformations. ... More

Restrictions of smooth functions to a closed subsetDec 11 2003Dec 12 2004We first provide an approach to the recent conjecture of Bierstone-Milman-Pawlucki on Whitney's old problem on smooth extendability of functions defined on a closed subset of a Euclidean space, using higher order paratangent bundle they introduced. For ... More

The Lp Cauchy sequence for one-dimensional BSDEs with linear growth generatorsDec 03 2011In this paper, the existence of $L^p(p>1)$ solutions for one-dimensional backward stochastic differential equations will be shown directly by proving that an approximation sequence is a Cauchy one in the $L^p$ sense.

New Interpretation of Equivalence Principle in General Relativity from the viewpoint of Micro-Macro dualityDec 23 2011We propose a new interpretation of the equivalence principle underlying Einstein's general relativity: a free-falling frame with gravitational force eliminated locally in a small spacetime region shows the existence of a boundary level, below which gravity ... More

Micro-Macro Duality and Emergence of Macroscopic LevelsMay 21 2007The mutual relation between quantum Micro and classical Macro is clarified by a unified formulation of instruments describing measurement processes and the associated amplification processes, from which some perspective towards a description of emergence ... More

Micro-Macro Duality in Quantum PhysicsFeb 14 2005Micro-Macro Duality means here the universal mutual relations between the microscopic quantum world and various macroscopic classical levels, which can be formulated mathematically as categorical adjunctions. It underlies a unified scheme for generalized ... More

Canonical extension of endomorphisms of type III factorsApr 24 2001We extend the notion of the canonical extension of automorphisms of type III factors to the case of endomorphisms with finite statistical dimensions. Following the automorphism case, we introduce two notions for endomorphisms of type III factors: modular ... More

Last zero time or Maximum time of the winding number of Brownian motionsJul 08 2014Dec 23 2014In this paper we consider the winding number, $\theta(s)$, of planar Brownian motion and study asymptotic behavior of the process of the maximum time, the time when $\theta(s)$ attains the maximum in the interval $0\le s \le t$. We find the limit law ... More

Topics and problems on favorite sites of random walksJun 13 2016In this article, we study special points of a simple random walk and a Gaussian free field, such as (nearly) favorite points, late points and high points. In section $2$, we extend results of [19] and suggest open problems for $d=2$. In section $3$, we ... More

Quantum phase transition from the topological viewpointJul 07 2013Jul 12 2013This study targets quantum phases which are characterized by topological properties and no associated with the symmetry breaking. We concern ourselves primarily with the transitions among these quantum phases. This type of quantum phase transition was ... More

Every sum system is divisibleAug 12 2007We show that every sum system is divisible. Combined with B. V. R. Bhat and R. Srinivasan's result, this shows that every product system arising from a sum system (and every generalized CCR flow) is either of type I or type III. A necessarily and sufficient ... More

Distributions of molecules in the circumnuclear disk and surrounding starburst ring in the Seyfert galaxy NGC 1068 observed with ALMAJun 01 2014Sensitive observations with ALMA allow astronomers to observe the detailed distributions of molecules with relatively weak intensity in nearby galaxies. In particular, we report distributions of several molecular transitions including shock and dust related ... More

A Multi-Transition Study of Molecules toward NGC 1068 based on High-Resolution Imaging Observations with ALMAOct 22 2014We present 0.8-mm band molecular images and spectra obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) toward one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068. Distributions of CO isotopic species ($^{13}$CO ... More

A statistical study of giant molecular clouds traced by $^{13}$CO, C$^{18}$O, CS, and CH$_3$OH in the disk of NGC 1068 based on ALMA observationsDec 03 2016We present $1''.4$ (98 pc) resolution ALMA observations of $^{13}$CO($J$=1-0), C$^{18}$O($J$=1-0), CS($J$=2-1) and CH$_3$OH($J_K$=$2_K$-$1_K$) molecular lines in the central $1'$ (4.2 kpc) region of NGC 1068 to study the physical and chemical properties ... More

Ultrabroadband direct detection of nonclassical photon statistics at telecom wavelengthAug 08 2013Broadband light sources play essential roles in diverse fields, such as high-capacity optical communications, optical coherence tomography, optical spectroscopy, and spectrograph calibration. Though an ultrabroadband nonclassical state from standard spontaneous ... More

Radio Search for H2CCC toward HD 183143 as a Candidate for a Diffuse Interstellar Band CarrierJun 09 2012To clarify the authenticity of a recently proposed identification of H2CCC (linear-C3H2) as a diffuse interstellar band carrier, we searched for the rotational transition of H2CCC at a frequency of 103 GHz toward HD 183143 using a 45-m telescope at the ... More

Observations of Ammonia in External Galaxies. II. Maffei 2Oct 25 2000The ammonia (J,K) = (1,1), (2,2), (3,3), and (4,4) transitions at 23.7 -- 24.1 GHz region were searched for in a nearby galaxy Maffei 2 to study relation between molecular abundances and physical conditions in galaxies. The (1,1), (2,2), and (3,3) emission ... More

Efficient generation of twin photons at telecom wavelengths with 10 GHz repetition-rate tunable comb laserSep 10 2014Efficient generation and detection of indistinguishable twin photons are at the core of quantum information and communications technology (Q-ICT). These photons are conventionally generated by spontaneous parametric down conversion (SPDC), which is a ... More

Classical and Quantum Contents of Solvable Game Theory on Hilbert SpaceMar 31 2005Apr 28 2005A simple and general formulation of the quantum game theory is presented, accommodating all possible strategies in the Hilbert space for the first time. The theory is solvable for the two strategy quantum game, which is shown to be equivalent to a family ... More

On the emergence of gauge structures and generalized spin when quantizing on a coset spaceAug 06 1993It has been known for some time that there are many inequivalent quantizations possible when the configuration space of a system is a coset space G/H. Viewing this classical system as a constrained system on the group G, we show that these inequivalent ... More

Quantum doubles of generalized Haagerup subfactors and their orbifoldsJan 30 2015We show how to compute the quantum doubles of generalized Haagerup subfactors for groups of even order and their equivariantizations and de-equivariantizations. We find the modular data for several small-index subfactors, including the Asaeda-Haagerup ... More

How to Observe Quantum Fields and Recover Them from Observational Data? -- Takesaki Duality as a Micro-Macro Duality --Apr 23 2006After the mathematical notion of "Micro-Macro Duality" for understanding mutual relations between microsopic quantum systems (Micro) and their macroscopic manifestations (Macro) is explained on the basis of the notion of sectors and order parameters, ... More

Bitwise MAP Algorithm for Group Testing based on Holographic TransformationJan 17 2014In this paper, an exact bitwise MAP (Maximum A Posteriori) estimation algorithm for group testing problems is presented. We assume a simplest non-adaptive group testing scenario including N-objects with binary status and M-disjunctive tests. If a group ... More

A weak homotopy equivalence type result related to Kirchberg algebrasOct 13 2018We obtain a weak homotopy equivalence type result between two topological groups associated with a Kirchberg algebra: the unitary group of the continuous asymptotic centralizer and the loop group of the automorphism group of the stabilization. This result ... More

Remarks on free mutual information and orbital free entropyJun 23 2013The present notes provide a proof of $i^*(\mathbb{C}P+\mathbb{C}(I-P)\,;\mathbb{C}Q+\mathbb{C}(I-Q)) = -\chi_\mathrm{orb}(P,Q)$ for any pair of projections $P,Q$ with $\tau(P)=\tau(Q)=1/2$. The proof includes new extra observations, such as a subordination ... More

Physics of singular points in quantum mechanicsDec 03 2003Defects or junctions in materials serve as a source of interactions for particles, and in idealized limits they may be treated as singular points yielding contact interactions. In quantum mechanics, these singularities accommodate an unexpectedly rich ... More

Classification of Noncommuting Quadrilaterals of FactorsApr 09 2007Apr 27 2007A quadrilateral of factors is an irreducible inclusion of factors $N \subset M$ with intermediate subfactors $P$ and $Q$ such that $P$ and $Q$ generate $M$ and the intersection of $P$ and $Q$ is $N$. We investigate the structure of a non-commuting quadrilateral ... More

Compact homomorphisms between algebras of $C(K)$-valued Lipschitz functionsMar 28 2018We give a complete description of homomorphisms between two Banach algebras of Lipschitz functions with values in continuous functions. We also characterize the compactness of those homomorphisms.

Diophantine inequality for equicharacteristic excellent Henselian local domainsJan 07 2008Oct 27 2008G. Rond has proved a Diophantine type inequality for the field of quotients of the convergent or formal power series ring in multivariables. We generalize his theorem to the field of the quotients of an excellent Henselian local domain in equicharacteristic ... More

Inequivalent Quantizations and Holonomy Factor from the Path-Integral ApproachSep 11 1996A path-integral quantization on a homogeneous space G/H is proposed based on the guiding principle `first lift to G and then project to G/H'. It is then shown that this principle gives a simple procedure to obtain the inequivalent quantizations (superselection ... More

A Universal Decline Law of Classical Novae. II. GK Persei 1901 and Novae in 2005Feb 21 2007Optical and infrared light-curves of classical novae are approximately homologous among various white dwarf (WD) masses and chemical compositions when free-free emission from optically thin ejecta dominates the continuum flux of novae. Such a homologous ... More

Recurrent novae as a progenitor system of Type Ia supernovae. I. RS Ophiuchi subclass --- Systems with a red giant companionApr 03 2001Theoretical light curves of four recurrent novae in outburst are modeled to obtain various physical parameters. They are those with a red giant companion, T CrB, RS Oph, V745 Sco, and V3890 Sgr. Our model includes irradiations of the companion star and ... More

A Light Curve Analysis of Recurrent and Very Fast Novae in our Galaxy, Magellanic Clouds, and M31May 24 2018We analyzed optical, UV, and X-ray light curves of 14 recurrent and very fast novae in our galaxy, Magellanic Clouds, and M31, and obtained their distances and white dwarf (WD) masses. Among the 14 novae, we found that eight novae host very massive ($\gtrsim ... More

Light Curve Analysis of Neon NovaeNov 21 2015We analyzed light curves of five neon novae, QU Vul, V351 Pup, V382 Vel, V693 CrA, and V1974 Cyg, and determined their white dwarf (WD) masses and distance moduli on the basis of theoretical light curves composed of free-free and photospheric emission. ... More

Modeling of the Super-Eddington Phase for Classical Novae: Five IUE NovaeNov 18 2006We present a light curve model for the super-Eddington luminosity phase of five classical novae observed with IUE. Optical and UV light curves are calculated based on the optically thick wind theory with a reduced effective opacity for a porous atmosphere. ... More

A Universal Decline Law of Classical NovaeJul 27 2006Oct 10 2006We calculate many different nova light curves for a variety of white dwarf masses and chemical compositions, with the assumption that free-free emission from optically thin ejecta dominates the continuum flux. We show that all these light curves are homologous ... More

A weak homotopy equivalence type result related to Kirchberg algebrasOct 13 2018Feb 25 2019We obtain a weak homotopy equivalence type result between two topological groups associated with a Kirchberg algebra: the unitary group of the continuous asymptotic centralizer and the loop group of the automorphism group of the stabilization. This result ... More

On Topological Terms in the O(3) Nonlinear Sigma ModelMay 24 1999Topological terms in the O(3) nonlinear sigma model in (1+1) and (2+1) dimensions are re-examined based on the description of the SU(2)-valued field $g$. We first show that the topological soliton term in (1+1) dimensions arises from the unitary representations ... More

Notes on Unfair Papers by Mebarki et al. on ``Quantum Nonsymmetric Gravity''Dec 06 1999It is pointed out that the essential parts of some recent papers by Mebarki {\it et al.} (hep-th/9911045, hep-th/9911046, hep-th/9911048, hep-th/9911049, dated 6 Nov.1999) are taken from a book written by Nakanishi and Ojima, published in 1990.

A Free Particle on a Circle with Point InteractionOct 14 1999The quantum dynamics of a free particle on a circle with point interaction is described by a U(2) family of self-adjoint Hamiltonians. We provide a classification of the family by introducing a number of subfamilies and thereby analyze the spectral structure ... More

Who has seen a free photon?Jan 30 2011While the notion of the position of photons is indispensable in the quantum optical situations, it has been known in mathematical physics that any position operator cannot be defined for a massless free particle with a non-zero finite spin. This dilemma ... More

On Quantisations, Quasi-probabilities and the Weak ValueMar 17 2017Apr 13 2017We propose a general framework of the quantum/quasi-classical transformations by introducing the concept of quasi-joint-spectral distribution (QJSD). Specifically, we show that the QJSDs uniquely yield various pairs of quantum/quasi-classical transformations, ... More

Particle production in models with helicity-0 graviton ghost in de Sitter spacetimeOct 27 2008We revisit the problem of the helicity-0 ghost mode of massive graviton in the de Sitter background. In general, the presence of a ghost particle, which has negative energy, drives the vacuum to be unstable through pair production of ghost particles and ... More

When photons are lying about where they have beenJun 02 2018Jul 02 2018The past of the photon in a nested Mach-Zehnder interferometer with an inserted Dove prism is analyzed. It is argued that the Dove prism does not change the past of the photon. Alonso and Jordan correctly point out that an experiment by Danan et al. demonstrating ... More

Infinite families of potential modular data related to quadratic categoriesJun 18 2019We present several infinite families of potential modular data motivated by examples of Drinfeld centers of quadratic categories. In each case, the input is a pair of involutive metric groups with Gauss sums differing by a sign, along with some conditions ... More

A Light Curve Analysis of Gamma-ray Nova V959 Mon -- Distance and White Dwarf MassApr 19 2018V959 Mon is one of the gamma-ray detected novae. It was optically discovered about 50 days after the gamma-ray detection due to proximity to the Sun. The nova speed class is unknown because of lack of the earliest half of optical light curve and short ... More

The UBV Color Evolution of Classical Novae. II. Color-Magnitude DiagramFeb 03 2016Mar 21 2016We have examined the outburst tracks of 40 novae in the color-magnitude diagram (intrinsic B-V color versus absolute V magnitude). After reaching the optical maximum, each nova generally evolves toward blue from the upper-right to the lower-left and then ... More

Prediction of Supersoft X-ray Phase during the 2006 Outburst of RS OphiuchiFeb 26 2006Mar 22 2006RS Ophiuchi is one of the well-observed recurrent novae and also a candidate progenitor of Type Ia supernovae. Its sixth recorded outburst was discovered on 12 February 2006. Detection of a supersoft X-ray phase will provide a firm confirmation of hydrogen ... More

A theoretical light-curve model for the 1985 outburst of RS OphiuchiMay 04 2000A theoretical light-curve model of the 1985 outburst of RS Ophiuchi is presented based on a thermonuclear runaway (TNR) model. The system consists of a very massive white dwarf (WD) with an accretion disk (ACDK) and a red giant (RG). The early phase of ... More

The nature of premaximum halts of classical nova outbursts: V723 Cassiopeiae and V463 ScutiJul 22 2004Aug 01 2004We present a new interpretation of long premaximum halts of nova outbursts. For V723 Cas (Nova Cas 1995) and V463 Sct (Nova Sct 2000), we have reproduced light curves, excluding the brightness maxima, starting from the long premaximum halt through the ... More

Prediction of supersoft X-ray phase, helium enrichment, and turn-off time in recurrent nova CI Aquilae 2000 outburstApr 28 2001Recurrent nova CI Aquilae is still bright 300 days after the optical maximum, showing the slowest evolution among recurrent novae. We predict the turn-off time of CI Aql 2000 outburst coming in August 2001 after a supersoft X-ray source (SSS) phase lasts ... More

A New Interpretation for the Second Peak of T Coronae Borealis Outbursts: A Tilting Disk around a Very Massive White DwarfMar 17 1999Mar 18 1999A new interpretation for the second peak of T Coronae Borealis (T CrB) outbursts is proposed based on a thermonuclear runaway (TNR) model. The system consists of a very massive white dwarf (WD) with a tilting accretion disk and a lobe-filling red-giant. ... More

Recurrent novae as progenitors of Type Ia supernovaeDec 11 2012Recurrent novae are binaries harboring a very massive white dwarf (WD), as massive as the Chandrasekhar mass, because of their short recurrence periods of nova outbursts of 10-100 years. Thus, recurrent novae are considered as candidates of progenitors ... More

Optical and Supersoft X-ray Light Curve Models of Classical Nova V2491 Cygni: A New Clue to the Secondary MaximumFeb 14 2009V2491 Cygni (Nova Cygni 2008 No.2) was detected as a transient supersoft X-ray source with the Swift XRT as early as 40 days after the outburst, suggesting a very massive white dwarf (WD) close to the Chandrasekhar limit. We present a unified model of ... More

Poly-$\mathbb{Z}$ group actions on Kirchberg algebras IOct 13 2018Toward the complete classification of poly-$\mathbb{Z}$ group actions on Kirchberg algebras, we prove several fundamental theorems that are used in the classification. In addition, as an application of them, we classify outer actions of poly-$\mathbb{Z}$ ... More

The group structure of the homotopy set whose target is the automorphism group of the Cuntz algebraMar 12 2019We determine the group structure of the homotopy set whose target is the automorphism group of the Cuntz algebra $O_{n+1}$ for finite n in terms of K-theory. We show that there is an example of a space for which the homotopy set is a non-commutative group, ... More

Nesting properties and anomalous band effect in MgB2Jun 29 2001First principle FLAPW band calculations of the new superconductor MgB2 were performed and the polarization function P12(Q) between the two p-bands mainly formed of boron pz-orbital was calculated. We found that P12(Q) is substantially enhanced around ... More

Quasi-probabilities in Conditioned Quantum Measurement and a Geometric/Statistical Interpretation of Aharonov's Weak ValueJul 21 2016We show that the joint behaviour of an arbitrary pair of quantum observables can be described by quasi-probabilities, which are extensions of the standard probabilities used for describing the behaviour of a single observable. The physical situations ... More

Metal Enrichment of Ly alpha Clouds and Intergalactic MediumSep 12 1997We have examined the metal enrichment of the intergalactic medium (IGM) based on a galactic wind model. A galactic wind driven by supernovae brings metallic gas to the IGM but not so far beyond the gravitational potential. The expanding velocity of the ... More

BPST instanton and Spin from inequivalent quantizationsOct 28 1993Nov 02 1993We present a simple alternative to Mackey's account of the (infinite) inequivalent quantizations possible on a coset space G/H. Our reformulation is based on the reduction ${\rm G \rightarrow G/H}$ and employs a generalized form of Dirac's approach to ... More

DGP with bubble of nothingFeb 12 2014Sep 03 2014We construct exact solutions with the bubble of nothing in the Dvali-Gabadadze-Porrati braneworld model. The configuration with a single brane can be constructed, unlike in the Randall-Sundrum braneworld model. The geometry on the single brane looks like ... More

Renormalized Newtonian Cosmic Evolution with Primordial Non-GaussianityJun 12 2007Jun 13 2007We study Newtonian cosmological perturbation theory from a field theoretical point of view. We derive a path integral representation for the cosmological evolution of stochastic fluctuations. Our main result is the closed form of the generating functional ... More

Supersymmetry and HomotopyMay 26 2000The homotopical information hidden in a supersymmetric structure is revealed by considering deformations of a configuration manifold. This is in sharp contrast to the usual standpoints such as Connes' programme where a geometrical structure is rigidly ... More

Monte-Carlo Simulation of J1 League Postseason System from the 2015 SeasonDec 02 2014Dec 23 2014In this paper, the new two stage and postseason system of J1 League, the top division of professional football in Japan, is simulated. Official regulation defines that the new postseason from the 2015 season consists of five teams selected by different ... More

Quantum Tunneling and Caustics under Inverse Square PotentialFeb 06 2002Mar 22 2002Quantization of a harmonic oscillator with inverse square potential $V(x)=(m{\omega^2}/2){x^2}+g/{x^2}$ on the line $-\infty<x<\infty$ is re-examined. It is shown that, for $0<g<3{\hbar^2}/(8m)$, the system admits a U(2) family of inequivalent quantizations ... More

Black versus Dark: Rapid Growth of Supermassive Black Holes in Dark Matter Halos at z ~ 6Feb 11 2019Feb 25 2019We report on the relation between the mass of supermassive black holes (SMBHs; M_BH) and that of hosting dark matter halos (M_h) for 49 z ~ 6 quasi-stellar objects (QSOs) with [CII]158um velocity-width measurements. Here, we estimate M_h assuming that ... More

A Unified Scheme of Measurement and Amplification Processes based on Micro-Macro Duality -- Stern-Gerlach experiment as a typical exampleOct 19 2008A unified scheme for quantum measurement processes is formulated on the basis of Micro-Macro duality as a mathematical expression of the general idea of quantum-classical correspondence. In this formulation, we can naturally accommodate the amplification ... More

Extreme value distributions of noncolliding diffusion processesJun 30 2010Jul 07 2010Noncolliding diffusion processes reported in the present paper are $N$-particle systems of diffusion processes in one-dimension, which are conditioned so that all particles start from the origin and never collide with each other in a finite time interval ... More

A Light Curve Analysis of 32 Recent Galactic Novae --- Distances and White Dwarf MassesMay 25 2019We obtained the absolute magnitudes, distances, and white dwarf (WD) masses of 32 recent galactic novae based on the time-stretching method for nova light curves. A large part of the light/color curves of two classical novae often overlap each other if ... More

A Theoretical Light-Curve Model for the Recurrent Nova V394 Coronae AustrinaeMar 31 2000A theoretical light curve for the 1987 outburst of V394 Coronae Austrinae (V394 CrA) is modeled to obtain various physical parameters of this recurrent nova. We then apply the same set of parametersto a quiescent phase and confirm that these parameters ... More

Mass accumulation efficiency in helium shell flashes for various white dwarf massesJul 30 2004We have calculated the mass accumulation efficiency during helium shell flashes on white dwarfs (WDs) of mass 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, and $1.35 M_{\odot}$ for the helium accretion rates $\log\dot M_{\rm He} \ (M_{\odot}$ yr$^{-1}) = -7.4$ to ... More