Results for "Y. Salathe"

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Time-domain characterization and correction of on-chip distortion of control pulses in a quantum processorJul 10 2019We introduce Cryoscope, a method for sampling on-chip baseband pulses used to dynamically control qubit frequency in a quantum processor. We specifically use Cryoscope to measure the step response of the dedicated flux control lines of two-junction transmon ... More
Quantum limited amplification and entanglement in coupled nonlinear resonatorsApr 17 2014We demonstrate a coupled cavity realization of a Bose Hubbard dimer to achieve quantum limited amplification and to generate frequency entangled microwave fields with squeezing parameters well below -12 dB. In contrast to previous implementations of parametric ... More
Realization of Deterministic Quantum Teleportation with Solid State QubitsFeb 22 2013Transferring the state of an information carrier from a sender to a receiver is an essential primitive in both classical and quantum communication and information processing. In a quantum process known as teleportation the unknown state of a quantum bit ... More
Optimized digital filtering techniques for radiation detection with HPGe detectorsApr 08 2015Mar 02 2016This paper describes state-of-the-art digital filtering techniques that are part of GEANA, an automatic data analysis software used for the GERDA experiment. The discussed filters include a novel, nonlinear correction method for ballistic deficits, which ... More
Realizing Rapid, High-Fidelity, Single-Shot Dispersive Readout of Superconducting QubitsJan 24 2017Jan 25 2017The speed of quantum gates and measurements is a decisive factor for the overall fidelity of quantum protocols when performed on physical qubits with finite coherence time. Reducing the time required to distinguish qubit states with high fidelity is therefore ... More
Structure of 29F in the Rotation-aligned Coupling Scheme of the Particle-Rotor ModelSep 07 2017Recent results from RIKEN/RIBF on the low-lying level structure of 29F are interpreted within the Particle-Rotor Model. We show that the experimental data can be understood in the Rotation-aligned Coupling Scheme, with the 5/2+ ground state as the bandhead ... More
Analysis of Spectroscopic Factors in 11Be and 12Be in the Nilsson Strong Coupling LimitAug 18 2017Spectroscopic factors in 10Be, 11Be and 12Be, extracted from (d,p), one neutron knockout, and (p,d) reactions are interpreted within the rotational model. Assuming that the ground state and first excited state of 11Be can be associated with the 1/2[220] ... More
An open access repository of images on plant health to enable the development of mobile disease diagnosticsNov 25 2015Apr 12 2016Human society needs to increase food production by an estimated 70% by 2050 to feed an expected population size that is predicted to be over 9 billion people. Currently, infectious diseases reduce the potential yield by an average of 40% with many farmers ... More
Targeting HIV-related Medication Side Effects and Sentiment Using Twitter DataApr 11 2014We present a descriptive analysis of Twitter data. Our study focuses on extracting the main side effects associated with HIV treatments. The crux of our work was the identification of personal tweets referring to HIV. We summarize our results in an infographic ... More
Novel technique for supernova detection with IceCubeJun 10 2011Jul 07 2011The current supernova detection technique used in IceCube relies on the sudden deviation of the summed photomultiplier noise rate from its nominal value during the neutrino burst, making IceCube a $\approx 3$ Megaton effective detection volume - class ... More
Using Deep Learning for Image-Based Plant Disease DetectionApr 11 2016Apr 15 2016Crop diseases are a major threat to food security, but their rapid identification remains difficult in many parts of the world due to the lack of the necessary infrastructure. The combination of increasing global smartphone penetration and recent advances ... More
$2νββ$ decay of $^{76}$Ge into excited states with GERDA Phase IJun 09 2015Two neutrino double beta decay of $^{76}$Ge to excited states of $^{76}$Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in ... More
Limit on the Radiative Neutrinoless Double Electron Capture of $^{36}$Ar from GERDA Phase IMay 05 2016May 12 2016Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of $^{36}$Ar has been performed with germanium ... More
Results on neutrinoless double beta decay of 76Ge from GERDA Phase IJul 17 2013Neutrinoless double beta decay is a process that violates lepton number conservation. It is predicted to occur in extensions of the Standard Model of particle physics. This Letter reports the results from Phase I of the GERmanium Detector Array (GERDA) ... More
Measurement of the half-life of the two-neutrino double beta decay of Ge-76 with the Gerda experimentDec 13 2012The primary goal of the GERmanium Detector Array (Gerda) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of Ge-76. High-purity germanium detectors made from material enriched in Ge-76 ... More
Understanding the Low-Energy Enhancement of the $γ$-ray Strength Function of $^{56}$FeJan 29 2018A model-independent technique was used to determine the $\gamma$-ray Strength Function ($\gamma$SF) of $^{56}$Fe down to $\gamma$-ray energies less than 1 MeV for the first time with GRETINA using the $(p,p')$ reaction at 16 MeV. No difference was observed ... More
Cylindrically-Symmetric Solutions in Conformal GravityDec 23 2009May 27 2010Cylindrically-symmetric solutions in Conformal Gravity are investigated and several new solutions are presented and discussed. Among them, a family of vacuum solutions, generalizations of the Melvin solution and cosmic strings of the Abelian Higgs model. ... More
Superconducting and Spinning Non-Abelian Flux TubesNov 07 2007Apr 11 2008We find new non-Abelian flux tube solutions in a model of $N_f$ scalar fields in the fundamental representation of SU(N)xU(1) with $N \leq N_f$ (the ``extended non-Abelian Higgs model''), and study their main properties. Among the solutions there are ... More
Full Formula for Heavy Quarkonium Energy Levels at Next-to-next-to-next-to-leading OrderAug 24 2014Aug 26 2016We derive a full formula for the energy level of a heavy quarkonium state identified by the quantum numbers $n$, $\ell$, $s$ and $j$, up to ${\cal O}(\alpha_s^5 m)$ and ${\cal O}(\alpha_s^5 m \log \alpha_s)$ in perturbative QCD. The QCD Bethe logarithm ... More
Corrections to quarkonium 1S energy level at O(alpha_S^4 m) from non-instantaneous Coulomb vacuum polarizationDec 26 2001Jan 28 2002We calculate O(alpha_S^4 m) and O(alpha_S^4 m log(alpha_S)) corrections to the quarkonium 1S energy level analytically, which have been overlooked in recent studies. These are the contributions from one Coulomb-gluon exchange with the 1-loop vacuum polarization ... More
Off-shell Suppression of Renormalons in Non-relativistic QCD BoundstatesOct 22 2001Apr 12 2002We study an effect of the off-shellness of the quark and antiquark inside a heavy quarkonium system on IR renormalons contained in the perturbative computations of the quarkonium energy levels. We demonstrate that, when the off-shellness p_Q^2 -m_Q^2 ... More
Identification of the Early Fermi LAT Gamma-Ray Bright Objects with Extragalactic VLBI sourcesAug 28 2009Nov 10 2009A list of 205 gamma-ray strong objects was reported recently as a result of a 3-month integration with the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope. We attempted identification of these objects, cross-correlating the gamma-ray ... More
Parsec-scale Jet in the Distant Gigahertz-Peaked Spectrum Quasar PKS 0858-279Jan 09 2009The high redshift GPS quasar PKS 0858-279 exhibits the following properties which make the source unusual. Our RATAN-600 monitoring of 1-22 GHz spectrum has detected broad-band radio variability with high amplitude and relatively short time scale. In ... More
Electronic State of Na_xCoO_2 Based on the Two Dimensional Triangular Lattice d-p ModelJun 05 2008The electronic state in a CoO_2 plane of the layered cobalt oxides Na_{x}CoO_2 is investigated by using the 11 band d-p model on a two-dimensional triangular lattice, where the tight-binding parameters are determined so as to fit the LDA band structure. ... More
An explanatory study of $^{11}$Li $β$ decay into $^9$Li and deuteronNov 24 1994The $\beta$-decay of $^{11}$Li into $^9$Li and {\it d} is studied using simple halo wave functions of $^{11}$Li. The sensitivity of the transition probability is elucidated on a description of the halo part and on a choice of the potential between $^9$Li ... More
Activators of Luminescence in Speleothems as Source of Major Mistakes in Interpretation of Luminescent Paleoclimatic RecordsSep 08 2009This work summarizes the main results of the operation of the International Program Luminescence of Cave Minerals of the commission on Physical Chemistry and Hydrogeology of Karst of UIS of UNESCO in the field of activators of speleothem luminescence. ... More
Supercurrent Interactions in Noncommutative Yang-Mills and IIB Matrix ModelNov 07 2000Jan 16 2001It is known that noncommutative Yang-Mills is equivalent to IIB matrix model with a noncommutative background, which is interpreted as a twisted reduced model. In noncommutative Yang-Mills, long range interactions can be seen in nonplanar diagrams after ... More
Mode conversion enhancement between silicon micro-slab and plasmonic nano-gap waveguidesDec 03 2012Apr 01 2013We investigate a short (~1.5{\mu}m) partially-corrugated tapered waveguide structure for mode coupling from a silicon micro-slab to a plasmonic nano-gap waveguide at the optical communication frequency. More than 80% transmission efficiency is reported ... More
Models of Markov processes with a random transition mechanismAug 23 2015Oct 17 2015The paper deals with a certain class of random evolutions. We develop a construction that yields an invariant measure for a continuous-time Markov process with random transitions. The approach is based on a particular way of constructing the combined ... More
Relic neutrino asymmetry generation from $ν_α- ν_s$ oscillationsDec 08 2000Active--sterile neutrino oscillations provide a mechanism by which large differences in the neutrino and antineutrino number densities can be created in the early universe. The quantum kinetic equations are employed in the study of these asymmetries, ... More
T-violation tests for relativity principlesJan 23 2003We consider the implications of a violation of the equivalence principle or of Lorentz invariance in the neutrino sector for the T-asymmetry $\Delta P_T \equiv P(\nu_{\alpha} \to \nu_{\beta}) - P(\nu_{\beta} \to \nu_{\alpha})$ in a three-flavour framework. ... More
Synchronised neutrino oscillations from self interaction and associated applicationsNov 05 2002Nov 11 2002A recent revival of interest in synchronised oscillations due to neutrino--neutrino forward scattering in dense gases has led to two interesting applications with notable outcomes: (i) cosmological bounds on neutrino--antineutrino asymmetries are improved ... More
Critical Behaviour near the Mott Metal-Insulator Transition in a Two-band Hubbard ModelJul 10 2001The Mott metal-insulator transition in the two-band Hubbard model in infinite dimensions is studied by using the linearized dynamical mean-field theory. The discontinuity in the chemical potential for the change from hole to electron doping is calculated ... More
Spherical Non-Abelian Solutions in Conformal GravityOct 06 2009Feb 14 2010We study static spherically-symmetric solutions of non-Abelian gauge theory coupled to Conformal Gravity. We find solutions for the self-gravitating pure Yang-Mills case as well as monopole-like solutions of the Higgs system. The former are localized ... More
Self-Gravitating Spherical Solutions of the non-minimally coupled non-Abelian Higgs ModelDec 01 2014Motivated by the Higgs Inflation scenario, we study static spherically-symmetric solutions of the non-Abelian Higgs model coupled non-minimally to Gravity. We find solutions for the self-gravitating sphaleron as well as monopole-like solutions and study ... More
Dynamically enhanced $B\to K^*π$ decays in perturbative QCDOct 08 2002Oct 22 2002We investigate the $B \to K^{*}\pi$ decays, one of hardly understandable processes among charmless B-meson decays, within the perturbative QCD method. Owing to the dynamically enhanced mechanism in PQCD, we obtain large branching ratios and large direct ... More
New Physics Search in B Meson DecaysMar 16 2000We discuss new physics search within the minimal supergravity model by using a possible large direct CP asymmetry in $B^{\pm} \to K^{\pm}\phi, K^{0}\pi^{\pm}$ decays and B meson rare decays.
Factorization in Color-Suppressed B Meson DecaysOct 22 1998We summerize the status of factorization hypothesis in the color-suppressed B meson decays : $B \to J/\psi K^{(*)}$. We present the general formalism for decay rates and polarization fractions with considering all possible non-factorizable contributions ... More
Top mass determination and O (alpha_S^5 m) correction to toponium 1S energy levelNov 19 2002Feb 16 2003Recently the full O(alpha_S^5 m, alpha_S^5 m log(alpha_S)) correction to the heavy quarkonium 1S energy level has been computed (except the a_3-term in the QCD potential). We point out that the full correction (including the log(alpha_S)-term) is approximated ... More
Duality in the Azbel-Hofstadter problem and the two-dimensional d-wave superconductivity with a magnetic fieldJul 05 2000A single-parameter family of lattice-fermion model is constructed. It is a deformation of the Azbel-Hofstadter problem by a parameter $h={$B%((BDelta}/t$ (quantum parameter). A topological number is attached to each energy band. A duality between the ... More
Intrinsic Structure and Kinematics of the Sub-Parsec Scale Jet of M87Sep 06 2007We report new results from a sub-parsec scale study of the inner jet in M87 performed at 15 GHz with the Very Long Baseline Array. We have detected a limb brightened structure of the jet along with a faint 3 mas long counter-feature which we also find ... More
Numerical study of disorder effects on the three-dimensional Hubbard modelMay 17 2000Combined effects of interactions and disorder are investigated using a finite temperature quantum Monte Carlo technique for the three-dimensional Hubbard model with random potentials of a finite range. Temperature dependence of the charge compressibility ... More
Antiferromagnetic, Charge and Orbital Ordered States of Na0.5CoO2 Based on the Two-Dimensional Triangular Lattice d-p ModelJun 05 2008We investigate the electronic state of a CoO_2 plane in the layered cobalt oxides Na_xCoO_2 using the 11 band d-p model on a two-dimensional triangular lattice, where the tight-binding parameters are determined so as to fit the LDA band structure. Effects ... More
Exact String-Like Solutions in Conformal GravityAug 06 2010Jun 10 2011The cylindrically-symmetric static vacuum equations of Conformal Gravity are solved for the case of additional boost symmetry along the axis. We present the complete family of solutions which describe the exterior gravitational field of line sources in ... More
Error estimates for binomial approximations of game put optionsJun 01 2012Oct 17 2013We construct algorithms via binomial approximations for computation of prices of game put options and obtain estimates of approximation errors.
Tracking Simulations Near Half-Integer Resonance at PEP-IIMay 20 2003Beam-beam simulations predict that PEP-II luminosity can be increased by operating the horizontal betatron tune near and above a half-integer resonance. However, effects of the resonance and its synchrotron sidebands significantly enhance betatron and ... More
Advances in domain independent linear text segmentationMar 30 2000This paper describes a method for linear text segmentation which is twice as accurate and over seven times as fast as the state-of-the-art (Reynar, 1998). Inter-sentence similarity is replaced by rank in the local context. Boundary locations are discovered ... More
Mott Transition in the Two-Dimensional Flux PhaseMay 16 2001Effects of the electron-electron interaction in the two-dimensional flux phase are investigated. We treat the half-filled Hubbard model with a magnetic flux $\pi$ per plaquette by the quantum Monte Carlo method. When the interaction is small, an antiferromagnetic ... More
Effects of ferromagnetic fluctuations on the electric and thermal transport properties in NaxCoO2Jun 03 2009We investigate the electronic states and the transport properties of the CoO2 plane in NaxCoO2 on the basis of the two-dimensional triangular lattice 11-band d-p model by using the fluctuation exchange approximation, where we consider the Coulomb interaction ... More
Nonconventional Polynomial CLTApr 02 2015Sep 07 2015We obtain a functional central limit theorem (CLT) for sums of the form $\xi_N(t)=\frac1{\sqrt N}\sum_{n=1}^{[Nt]}\big(F(X(q_1(n)),...,X(q_\ell(n)))-\bar F\big)$ where $q_1,...,q_\ell$ are polynomials.
Perfect Fluid Spherically-Symmetric Solutions in Massive GravityDec 08 2011Jun 20 2012We study spherically-symmetric solutions in Massive Gravity generated by matter sources with polytropic equation of state. We concentrate in the non-perturbative regime where the mass term non-linearities are important, and present the main features of ... More
Phenomenological Applications of $k_T$-Factorization (--Large Direct CP-Asymmetry in B-meson Decays--)Oct 29 2004We discuss applications of the perturbative QCD approach in the exclusive non-leptonic two body B-meson decays. We briefly review its ingredients and some important theoretical issues on the factorization approaches. PQCD results are compatible with present ... More
On the determination of the relative sign of $a_1$ and $a_2$ from polarization measurements in $B^- \rightarrow ρ^- {D^*}^o$ decaySep 26 1994Oct 05 1994We point out that polarization measurements such as the longitudinal fraction and the transverse left-right asymmetry in the Bauer-Stech-Wirbel (BSW) class III processes involving two final vector mesons, $B^- \ra \rho^- {D^*}^o$ taken as an example, ... More
Perturbative heavy quarkonium spectrum at next-to-next-to-next-to-leading orderSep 25 2013Jan 23 2014We compute the energy levels of some of the lower-lying heavy quarkonium states perturbatively up to O(alpha_s^5*m) and O(alpha_s^5*m*log[alpha_s]). Stability of the predictions depends crucially on the unknown 4-loop pole-MSbar mass relation. We discuss ... More
Unifying treatment of nonequilibrium and unstable dynamics of cold bosonic atom system with time-dependent order parameter in Thermo Filed DynamicsJul 12 2010The coupled equations which describe the temporal evolution of the Bose-Einstein condensed system are derived in the framework of nonequilibrium Thermo Field Dynamics. The key element is that they are not the naive assemblages of presumable equations, ... More
Volume Preserving Diffeomorphism and Noncommutative BranesOct 06 2000We give a representation of the volume preserving diffeomorphism of $\bR^p$ in terms of the noncommutative (p-2)-branes whose kinetic term is described by the Hopf term. In the static gauge, the (p-2)-brane can be described by the free fields and it suggests ... More
Higher order corrections to the large scale matter power spectrum in the presence of massive neutrinosSep 04 2008Oct 06 2008We present the first systematic derivation of the one-loop correction to the large scale matter power spectrum in a mixed cold+hot dark matter cosmology with subdominant massive neutrino hot dark matter. Starting with the equations of motion for the density ... More
Proca Q Tubes and their Coupling to GravityNov 06 2016The Einstein-Proca system is studied in the case of a complex vector-field self-interacting through an appropriate potential with a global U(1) symmetry. The corresponding equations for a static, cylindrically symmetric metric and matter fields are then ... More
Penguin Contributions in the Lifetime Difference between $B_s$ and $B_d$, and a Possible New PhysicsOct 19 1998We consider penguin contributions to the lifetime splitting between the $B_s$ and the $B_d$ meson. In the Standard Model the penguin effects are found to be opposite in sign, but of similar magnitude as the contributions of the current-current operators, ... More
Molecular-Gas Superwind from the Face-on Wolf-Rayet Galaxy MRK 1259Mar 15 1998We report results of $^{12}$CO ($J=1$-0) mapping observations of the Wolf-Rayet starburst galaxy Mrk 1259 which has optical evidence for the superwind seen from a nearly pole-on view. The CO emission is detected in the central 4 kpc region. The nuclear ... More
Normal form and solitonsJun 13 2002We present a review of the normal form theory for weakly dispersive nonlinear wave equations where the leading order phenomena can be described by the KdV equation. This is an infinite dimensional extension of the well-known Poincar\'e-Dulac normal form ... More
Superconductivity and Density Wave in the Quasi-One-Dimensional Systems: Renormalization Group StudyOct 31 2004The anisotropic superconductivity and the density wave have been investigated by applying the Kadanoff-Wilson renormalization group technique to the quasi-one-dimensional system with finite-range interactions. It is found that a temperature (T) dependence ... More
Spherical Structures in Conformal Gravity and its Scalar-Tensor ExtensionJul 11 2009Nov 24 2009We study spherically-symmetric structures in Conformal Gravity and in a scalar-tensor extension and gain some more insight about these gravitational theories. In both cases we analyze solutions in two systems: perfect fluid solutions and boson stars of ... More
O(alpha_s^5 m) quarkonium 1S spectrum in large-beta_0 approximation and renormalon cancellationJul 24 2000Nov 08 2000Presently the quarkonium spectrum, written in terms of the quark MSbar-mass, is known at O(alpha_s^3 m) accuracy. We point out that in order to achieve O(alpha_s^4 m) accuracy it is sufficient to calculate further (I) the O(alpha_s^4 m) relation between ... More
Scaling near random criticality in two-dimensional Dirac fermionsJul 02 1998Recently the existence of a random critical line in two dimensional Dirac fermions is confirmed. In this paper, we focus on its scaling properties, especially in the critical region. We treat Dirac fermions in two dimensions with two types of randomness, ... More
Charge and Orbital Ordering in the Triangular-Lattice t_{2g}-Orbital System in One Dimension: A Possible Ground State of Bi_xV_8O_{16}Oct 10 2001We consider the possible charge and orbital ordering in a Hollandite compound Bi_xV_8O_{16}, which is a new one-dimensional triangular-lattice t_{2g}-orbital system. Using the strong-coupling perturbation theory, we derive the effective spin-orbit Hamiltonian ... More
Analytical treatment of neutrino asymmetry equilibration from flavour oscillations in the early universeMar 19 2002Jun 05 2002A recent numerical study by A. D. Dolgov, S. H. Hansen, S. Pastor, S. T. Petcov, G. G. Raffelt, and D. V. Semikoz (DHPPRS) [hep-ph/0201287] found that complete or partial equilibrium between all active neutrino flavours can be achieved before the big ... More
Kernels for products of Hilbert L-functionsMay 07 2019We study kernel functions of L-functions and products of L-functions of Hilbert cusp forms over real quadratic fields. This extends the results on elliptic modualr forms by Diamantis and C. O'Sullivan. .
Decay Constants $f_{D_s^*}$ and $f_{D_s}$ from ${\bar{B}}^0\to D^+ l^- {\barν}$ and ${\bar{B}}^0\to D^+ D_s^{-(*)}$ DecaysOct 15 1998Oct 22 1998We calculate the decay constant of $D_s$ and $D_s^{*}$ with $\bar{B}^0 \ra D^{+}\ell^{-}\nu$ and $\bar{B}^0 \ra D^{+}D_s^{-(*)}$ decays. In our analysis we assume that factorization ansatz works and used two different form factor behaviours (constant ... More
Backwards on Minkowski's road. From 4D to 3D Maxwellian electromagnetismJul 16 2008Minkowski's concept of a four-dimensional physical space is a central paradigm of modern physics. The three-dimensional Maxwellian electrodynamics is uniquely generalized to the covariant four-dimensional form. Is the (1+3) decomposition of the covariant ... More
Local Procrustes for Manifold Embedding: A Measure of Embedding Quality and Embedding AlgorithmsJun 16 2008We present the Procrustes measure, a novel measure based on Procrustes rotation that enables quantitative comparison of the output of manifold-based embedding algorithms (such as LLE (Roweis and Saul, 2000) and Isomap (Tenenbaum et al, 2000)). The measure ... More
Plateaux Transitions in the Pairing Model:Topology and Selection RuleJul 01 1999Based on the two-dimensional lattice fermion model, we discuss transitions between different pairing states. Each phase is labeled by an integer which is a topological invariant and characterized by vortices of the Bloch wavefunction. The transitions ... More
VLBI Surveys of Active Galactic NucleiApr 07 2008A review is given on the current status and selected results from large VLBI surveys of compact extragalactic radio sources made between 13 cm and 3 mm wavelengths and covering the entire sky. More than 4200 objects are observed and imaged with dynamic ... More
Space-time Geometry in Exactly Solvable Quantum Dilaton GravityOct 23 1993Nov 04 1993We describe in detail how one can extract space-time geometry in an exactly solvable model of quantum dilaton gravity of the type proposed by Callan, Giddings, Harvey and Strominger ( CGHS ). Based on our previous work, in which a model with 24 massless ... More
Extraction of Black Hole Geometry in Exactly Quantized Two Dimensional Dilaton GravityOct 23 1993Based on our previous work, in which a model of two dimensional dilaton gravity of the type proposed by Callan, Giddings, Harvey and Strominger was rigorously quantized, we explicitly demonstrate how one can extract space-time geometry in exactly solvable ... More
Free-Energy Calculations in Protein Folding by Generalized-Ensemble AlgorithmsFeb 16 2001We review uses of the generalized-ensemble algorithms for free-energy calculations in protein folding. Two of the well-known methods are multicanonical algorithm and replica-exchange method; the latter is also referred to as parallel tempering. We present ... More
Neutrino mass in cosmology: status and prospectsNov 06 2011I give an overview of the effects of neutrino masses in cosmology, focussing on the role they play in the evolution of cosmological perturbations. I discuss how recent observations of the cosmic microwave background anisotropies and the large-scale matter ... More
From Classical Mechanics with Doubled Degrees of Freedom to Quantum Field Theory for Nonconservative SystemJul 04 2013Aug 02 2013The $2 \times 2$-matrix structure of Green's functions is a common feature for the real-time formalisms of quantum field theory under thermal situations, such as the closed time path formalism and Thermo Field Dynamics (TFD). It has been believed to originate ... More
Dilatonic Dark MatterOct 16 1998We study the possibility that the dilaton plays the role of the dark matter of the universe. We find that the condition for the dilaton to be the dark matter of the universe strongly restricts its mass to be around 0.5 keV or 270 MeV. For the other mass ... More
Magnetoelectrical control of nonreciprocal microwave response in a multiferroic helimagnetJul 23 2016Control of physical property in terms of external fields is essential for contemporary technologies. The conductance can be controlled by a gate electric field in a field effect transistor, which is a main component of the integrated circuit. Optical ... More
Superconducting islands, phase fluctuations and the superconductor-insulator transitionAug 13 2007Properties of disordered thin films are discussed based on the viewpoint that superconducting islands are formed in the system. These lead to superconducting correlations confined in space, which are known to form spontaneously in thin films. Application ... More
Anisotropy on the Fermi Surface of the Two-Dimensional Hubbard ModelJun 21 2001Jun 16 2002We investigate anisotropic charge fluctuations in the two-dimensional Hubbard model at half filling. By the quantum Monte Carlo method, we calculate a momentum-resolved charge compressibility $\kappa (\bm{k}) = {d < n(\bm{k}) >}/{d \mu}$, which shows ... More
Electronic states and pairing symmetry in the two-dimensional 16 band d-p model for iron-based superconductorAug 08 2008Jun 11 2009The electronic states of the FeAs plane in iron-based superconductors are investigated on the basis of the two-dimensional 16-band d-p model, where the tight-binding parameters are determined so as to fit the band structure obtained by the density functional ... More
Collapse of Charge Gap in Random Mott InsulatorsJul 14 1998Effects of randomness on interacting fermionic systems in one dimension are investigated by quantum Monte-Carlo techniques. At first, interacting spinless fermions are studied whose ground state shows charge ordering. Quantum phase transition due to randomness ... More
Island formation in disordered superconducting thin films at finite magnetic fieldsDec 28 2007Apr 16 2008The existence of "superconducting islands" (i.e., locally confined regions with superconducting correlations) in amorphous superconducting thin films can account for numerous experimental findings. Such spatial fluctuations in the superconducting gap ... More
Possible huge enhancement in the radiative decay of the weal W boson into the charmed $D_{s} $ mesonMar 24 1993We point out that the rare decay mode $W^{\pm} \rightarrow \gamma + D^{\pm}_{s} $ could be spectacularly enhanced, with a branching ratio around $10^{-6} $ which is three order of magnitude larger than previous predictions. Its observation will determine ... More
Dilatonic Dark Matter and Unified Cosmology -- a New Paradigm --Oct 15 1998We study the possibility that the dilaton -- the fundamental scalar field which exists in all the existing unified field theories -- plays the role of the dark matter of the universe. We find that the condition for the dilaton to be the dark matter strongly ... More
More on Parametrization Relevant to Describe Violation of CP, T and CPT Symmetries in the $K^0-\bar{K^0}$ SystemJul 31 1999To study violation of CP, T and/or CPT symmetries in the $K^0-\bar{K^0}$ systems, one has to parametrize the relevant mixing parameters and decay amplitudes in such a way that each parameter represents violation of these symmetries in a well-defined way. ... More
Gravitational Lensing and the Redshift Distribution of $B>25$ galaxiesAug 25 1996In addition to the determination of the mass distribution of lenses (see P. Schneider, this conference), strong and weak lensing can also be powerfull tools to analyse the redshift distribution of faint galaxies. In this review, I summarize the present ... More
Boundary Conditions and Modes of the Vertically Hanging ChainDec 01 2014The hanging chain is a very instructive system for demonstrating more advanced methods and ideas for the analysis of normal modes of one-dimensional systems, beyond the standard ordinary (horizontal) string. Accordingly, the normal modes of the hanging ... More
Auxiliary-field quantum Monte Carlo methods in nucleiJul 07 2016Auxiliary-field quantum Monte Carlo methods enable the calculation of thermal and ground state properties of correlated quantum many-body systems in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization ... More
Contribution of Stellar Flares to the Diffuse Component of Galactic Gamma-RaysSep 07 2009It is well known that the diffuse gamma-rays are produced by the collisions between the galactic cosmic rays with the stellar matter (Hayakawa-Morrison Hypothesis). In this paper the author tries to estimate the contribution of star flares in the low ... More
7Li NMR Studies of LiCrO2Oct 15 2013We report on 7Li NMR studies of a spin S = 3/2 triangular lattice antiferromagnet LiCrO2 (Neel temperature TN = 62 K) in the paramagnetic state by using the free-induction decay of 7Li nuclear magnetization. We observed critical divergence of the 7Li ... More
Slow transverse relaxation of the Zn-neighbor Cu nuclear spins in YBa2(Cu{1-x}Znx)4O8Oct 16 2005An explanation is given for the recent observation in the plane-site Cu nuclear quadrupole resonance (NQR) study of a heavily Zn-substituted YBa$_2$(Cu$_{1-x}$Zn$_x$)$_4$O$_{8}$ that the Cu nuclear spin-spin relaxation time $T_{2G}$ near the impurity ... More
What is the present-day status of The Copernican Principle?May 13 2005I point out that according to the Copernican principle our universe is not unique. The way to make sense out of this statement is for us to construct a gravitational instanton that will tunnel out of our vacuum into another, to form a universe other than ... More
Saturation of Nuclear Matter and Roles of Many-Body Forces: nuclear matter in neutron stars probed by nucleus-nucleus scatteringApr 24 2016Yoichiro Nambu put a great foot print in nuclear physics in the era of its fundamental developments including his pioneering insight into essential ingredients of repulsive core of nuclear force and its relation to the saturation of nuclear matter. The ... More
Tracking of magnetic flux concentrations over a five-day observation and an insight into surface magnetic flux transportMay 09 2016Jun 04 2016The solar dynamo problem is the question of how the cyclic variation in the solar magnetic field is maintained. One of the important processes is the transport of magnetic flux by surface convection. To reveal this process, the dependence of the squared ... More
Scalar and Pseudoscalar Glueball Masses within a Gaussian Wavefunctional ApproximationApr 02 2012Jun 07 2012The lowest scalar and pseudoscalar glueball masses are evaluated by means of the time-dependent variational approach to the Yang-Mills gauge theory without fermions in the Hamiltonian formalism within a Gaussian wavefunctional approximation. The glueball ... More
Family Gauge Symmetry as an Origin of Koide's Mass Formula and Charged Lepton SpectrumDec 11 2008May 12 2009Koide's mass formula is an empirical relation among the charged lepton masses which holds with a striking precision. We present a model of charged lepton sector within an effective field theory with U(3) \times SU(2) family gauge symmetry, which predicts ... More
Recent Theoretical Progress in ttbar Threshold AnalysesNov 29 1999I review the theoretical progress made in these 4 years concerning the process e+e- -> ttbar in the threshold region. I summarize the progress towards each of the three major physics goals that should be achieved at ttbar threshold region.