Results for "Y. Matsuda"

total 35953took 0.14s
Rotational Symmetry Breaking in the Hidden-Order Phase of URu2Si2Jul 27 2011A second-order phase transition is characterized by spontaneous symmetry breaking. The nature of the broken symmetry in the so-called "hidden order" phase transition in the heavy fermion compound URu2Si2, at transition temperature T_h=17.5 K, has posed ... More
Cyclotron Resonance in the Hidden-Order Phase of URu2Si2Jul 17 2012We report the first observation of cyclotron resonance in the hidden-order phase of ultra-clean URu$_2$Si$_2$ crystals, which allows the full determination of angle-dependent electron-mass structure of the main Fermi-surface sheets. We find an anomalous ... More
Optical evidence of type-II Weyl semimetals MoTe$_2$ and WTe$_2$Feb 26 2019The carrier dynamics and electronic structures of type-II Weyl semimetal candidates MoTe$_2$ and WTe$_2$ have been investigated by using temperature-dependent optical conductivity [$\sigma(\omega)$] spectra. Two kinds of Drude peaks (narrow and broad) ... More
Thermodynamic evidence for broken fourfold rotational symmetry in the hidden-order phase of URu2Si2Jul 17 2012Jul 19 2012Despite more than a quarter century of research, the nature of the second-order phase transition in the heavy-fermion metal URu$_2$Si$_2$ remains enigmatic. The key question is which symmetry is being broken below this "hidden order" transition. We review ... More
Magnetic, thermal, and transport properties on single crystals of antiferromagnetic Kondo-lattice Ce2PdSi3May 10 2000Magnetization, heat capacity, electrical resistivity, thermoelectric power, and Hall effect have been investigated on single-crystalline Ce_2PdSi_3. This compound is shown to order antiferromagnetically below N'eel temperature (T_N) \~3 K. The Sommerfeld ... More
Curves in R^n with finite total first curvature arising from the solutions of an ODEAug 23 2013We use the solution set of a real ordinary differential equation which has order n which is at least 2 to construct a smooth curve C in R^n. We describe when C is a proper embedding of infinite length with finite total first curvature.
Flavor Symmetry on Non-Commutative Compact Space and $SU(6) \times SU(2)_R$ ModelJul 26 2001Oct 11 2001In the four-dimensional effective theory from string compactification discrete flavor symmetries arise from symmetric structure of the compactified space and generally contain both the $R$ symmetry and non-$R$ symmetry. We point out that a new type of ... More
Variational Approach to the Chiral Phase Transition in the Linear Sigma ModelNov 11 2008The chiral phase transition at finite temperature is investigated in the linear sigma model, which is regarded as a low energy effective theory of QCD with three momentum cutoff, in the variational method with the Gaussian approximation in the functional ... More
Fulde-Ferrell-Larkin-Ovchinnikov State in Heavy Fermion SuperconductorsFeb 21 2007The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is a novel superconducting state in a strong magnetic field characterized by the formation of Cooper pairs with nonzero total momentum (k \uparrow, -k+q \downarrow), instead of the ordinary BCS pairs (k ... More
Non-Anomalous Flavor Symmetries and $SU(6) \times SU(2)_R$ ModelJun 24 2002Oct 21 2002We introduce the flavor symmetry ${\bf Z}_M \times {\bf Z}_N \times D_4$ into the $SU(6) \times SU(2)_R$ string-inspired model. The cyclic group ${\bf Z}_M$ and the dihedral group $D_4$ are R symmetries, while ${\bf Z}_N$ is a non-R symmetry. By imposing ... More
Frustration-driven successive metamagnetic transitions in TbB4Sep 07 2007Aug 21 2008Resonant magnetic x-ray diffraction experiments on the Shastry-Sutherland lattice TbB$_4$ were carried out under strong pulsed magnetic fields up to 30 T. TbB$_4$ exhibits a multi-step magnetization process above 16 T when magnetic fields are applied ... More
Majorana quantization and half-integer thermal quantum Hall effect in a Kitaev spin liquidMay 14 2018Aug 01 2018The quantum Hall effect (QHE) in two-dimensional (2D) electron gases, which is one of the most striking phenomena in condensed matter physics, involves the topologically protected dissipationless charge current flow along the edges of the sample. Integer ... More
X-ray Magnetic Circular Dichroism of Valence Fluctuating State in Eu at High Magnetic FieldsJan 27 2009Jun 19 2009X-ray magnetic circular dichroism (XMCD) at the Eu L-edge (2p->5d) in two compounds exhibiting valence fluctuation, namely EuNi2(Si0.18Ge0.82)2 and EuNi2P2, has been investigated at pulsed high magnetic fields of up to 40 T. A distinct XMCD peak corresponding ... More
Nematic and meta-nematic transitions in the iron pnictidesJul 04 2012Strongly interacting electrons can exhibit novel collective phases, among which the electronic nematic phases are perhaps the most surprising as they spontaneously break rotational symmetry of the underlying crystal lattice. The electron nematicity has ... More
Quantum sensing of local magnetic field texture in strongly correlated electron systems under extreme conditionsDec 25 2018An important feature of strong correlated electron systems is the tunability between interesting ground states such as unconventional superconductivity and exotic magnetism. Pressure is a clean, continuous and systematic tuning parameter. However, due ... More
A search for galaxies in and around an HI overdense region at z=5Jan 12 2010We present the discovery of a large-scale structure of emission-line galaxies at redshift z=4.86 behind a massive cluster of galaxies, A1689. Previous spectroscopic observations of a galaxy, A1689-7.1 at z=4.87, near this structure, revealed a possible ... More
Superstructure-induced splitting of Dirac cones in siliceneJan 31 2019Atomic scale engineering of two-dimensional materials could create devices with rich physical and chemical properties. External periodic potentials can enable the manipulation of the electronic band structures of materials. A prototypical system is 3x3-silicene/Ag(111), ... More
Diagonal F-thresholds and F-pure thresholds of Hibi ringsJan 27 2012Hibi rings are a kind of graded toric ring on a finite distributive lattice $D = J(P)$, where $P$ is a partially ordered set. In this paper, we compute diagonal F-thresholds and F-pure thresholds of Hibi rings.
FFLO state in thin superconducting filmsOct 18 2007We present the analysis of the inhomogeneous Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting state in thin superconducting films in the parallel magnetic field. For the tetragonal crystal symmetry (relevant to CeCoIn$_{5}$ - the most probable ... More
Activity report of ILD-TPC Asia groupMar 30 2014The purpose of ILD-TPC Asia group is realization of high precision Time Projection Chamber (TPC) with Gas Electron Multiplier (GEM) as a central tracker in International Linear Collider (ILC). We have been studying the many R&D items to build the real ... More
Can the SO(10) Model with Two Higgs Doublets Reproduce the Observed Fermion Masses?Oct 04 2000Apr 12 2001It is usually considered that the SO(10) model with one 10 and one 126 Higgs scalars cannot reproduce the observed quark and charged lepton masses. Against this conventional conjecture, we find solutions of the parameters which can give the observed fermion ... More
Broken symmetries in URu2Si2Jun 19 2014To resolve the nature of the hidden order below 17.5\,K in the heavy fermion compound URu$_2$Si$_2$, identifying which symmetries are broken below the hidden order transition is one of the most important steps. Several recent experiments on the electronic ... More
Nodal Structure of Unconventional Superconductors Probed by the Angle Resolved Thermal Transport MeasurementsNov 14 2006Over the past two decades, unconventional superconductivity with gap symmetry other than s-wave has been found in several classes of materials, including heavy fermion (HF), high-T_c, and organic superconductors. Unconventional superconductivity is characterized ... More
Tunneling Spectra of Skutterudite PrOs_4Sb_{12}Jun 06 2003Aug 11 2003The tunnel conductance in normal-metal / insulator / PrOs$_4$Sb$_{12}$ junctions is theoretically studied, where skutterudite PrOs$_4$Sb$_{12}$ is considered to be an unconventional superconductor. The conductance are calculated for several pair potentials ... More
Quantum critical point lying beneath the superconducting dome in iron-pnictidesApr 23 2013Whether a quantum critical point (QCP) lies beneath the superconducting dome has been a long-standing issue that remains unresolved in many classes of unconventional superconductors, notably cuprates, heavy fermion compounds and most recently iron-pnictides. ... More
Coexistence of orbital and quantum critical magnetoresistance in FeSe$_{1-x}$S$_{x}$Mar 13 2019The recent discovery of a non-magnetic nematic quantum critical point (QCP) in the iron chalcogenide family FeSe$_{1-x}$S$_{x}$ has raised the prospect of investigating, in isolation, the role of nematicity on the electronic properties of correlated metals. ... More
Magneto-elastic coupling in Fe-based superconductorsDec 05 2017We used polarization-resolved Raman scattering to study the magneto-elastic coupling in the parent compounds of several families of Fe-based superconductors (BaFe2As2, EuFe2As2, NaFeAs, LiFeAs, FeSe and LaFeAsO). We observe an emergent Ag-symmetry As ... More
Spin-wave induced phonon resonance in multiferroic BiFeO$_3$Mar 02 2018We report the direct observation of a "resonance" mode in the lowest-energy optic phonon very near the zone center around (111) in the multiferroic BiFeO$_3$ using neutron scattering methods. The phonon scattering intensity is enhanced when antiferromagnetic ... More
What Powers Lyman alpha Blobs?Jul 28 2015Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope Compact Array ... More
Measurement of ultra-low heating rates of a single antiproton in a cryogenic Penning trapJan 28 2019We report on the first detailed study of motional heating in a cryogenic Penning trap using a single antiproton. Employing the continuous Stern-Gerlach effect we observe cyclotron quantum transition rates of 6(1) quanta/h and an electric field noise spectral ... More
On Cannon-Thurston maps for relatively hyperbolic groupsJun 26 2012Baker and Riley proved that a free group of rank 3 can be contained in a hyperbolic group as a subgroup for which the Cannon-Thurston map is not well-defined. By using their result, we show that the phenomenon occurs for not only a free group of rank ... More
Incidence Angle and Polarization Dependence of Photo-Induced FMR in Co/Pd MultilayersApr 16 2014Dependence of photo-induced FMR (phi-FMR) on incident angle of excitation and probing laser beams has been studied in a [Co (dCo = 0.78 nm) / Pd (dPd = 0.81 nm) ]5 multi-layer film with the aim to find experimentally the limitation of inducement and detection ... More
Universal magnetic structure of the half-magnetization phase in Cr-based spinelsJul 28 2009Using an elastic neutron scattering technique under a pulsed magnetic field up to 30 T, we determined the magnetic structure in the half-magnetization plateau phase in the spinel CdCr$_2$O$_4$. The magnetic structure has a cubic $P4_3$32 symmetry, which ... More
Evolution of Paramagnetic Quasiparticle Excitations Emerged in the High-Field Superconducting Phase of CeCoIn5Mar 08 2011We present In NMR measurements in a novel thermodynamic phase of CeCoIn5 in high magnetic field, where exotic superconductivity coexists with the incommensurate spin-density wave order. We show that the NMR spectra in this phase provide direct evidence ... More
Penetration depth, lower critical fields, and quasiparticle conductivity in Fe-arsenide superconductorsApr 24 2009In this article, we review our recent studies of microwave penetration depth, lower critical fields, and quasiparticle conductivity in the superconducting state of Fe-arsenide superconductors. High-sensitivity microwave surface impedance measurements ... More
Disordered Ground State and Magnetic Field-Induced Long-Range Order in an S=3/2 Antiferromagnetic Honeycomb Lattice Compound Bi3Mn4O12(NO3)Dec 03 2010Bi3Mn4O12(NO3), in which the Mn4+ ions carry S=3/2, is the first honeycomb lattice system that shows no long-range magnetic order. Using neutron scattering, we have determined that short-range antiferromagnetic correlations develop at low temperatures. ... More
Proving Nontrivial Topology of Pure Bismuth by Quantum ConfinementMay 11 2016Dec 03 2016The topology of pure Bi is controversial because of its very small ($\sim$10 meV) band gap. Here we perform high-resolution angle-resolved photoelectron spectroscopy measurements systematically on 14$-$202 bilayers Bi films. Using high-quality films, ... More
Superconducting Gap Function in Antiferromagnetic Heavy-Fermion UPd_2Al_3 Probed by Angle Resolved Magnetothermal Transport MeasurementsMay 11 2004The superconducting gap structure of heavy fermion UPd_2Al_3, in which unconventional superconductivity coexists with antiferromagnetic (AF) order with atomic size local moments, was investigated by the thermal conductivity measurements in a magnetic ... More
Antiproton beams with low energy spread for antihydrogen productionFeb 25 2019A low energy antiproton transport from the ASACUSA antiproton accumulation trap (MUSASHI trap) to the antihydrogen production trap (double cusp trap) is developed. The longitudinal antiproton energy spread after the transport line is 0.23 +- 0.02 eV, ... More
Anomalous quasiparticle transport in the superconducting state of CeCoIn5Jun 03 2005We report on a study of thermal Hall conductivity k_xy in the superconducting state of CeCoIn_5. The scaling relation and the density of states of the delocalized quasiparticles, both obtained from k_xy, are consistent with d-wave superconducting symmetry. ... More
Antiferromagnetic ordering and disappearance of pseudogap within the vortex core of Tl_2Ba_2CuO_{6+δ}Jun 19 2002Spatially-resolved NMR is used to probe the magnetism in and around the vortex core of nearly optimally-doped Tl_2Ba_2CuO_{6+\delta} (T_c=85K). The NMR relaxation rate T_1^{-1} at ^{205}Tl site, at which antiferromagnetic (AF) fluctuation can be monitored ... More
Neutron Electric Dipole Momento in Two-Higgs-Doublet ModelSep 21 1994The effect of the "chromo-electric" dipole moment on the electric dipole moment(EDM) of the neutron is studied in the two-Higgs-doublet model. The Weinberg's operator $O_{3g}=GG\t G$ and the operator $O_{qg}=\bar q\sigma\t Gq$ are both investigated in ... More
Suppression of the antiferromagnetic order when approaching the superconducting state in a phase-separated crystal of K$_x$Fe$_{2-y}$Se$_2$Aug 30 2017We have combined elastic and inelastic neutron scattering techniques, magnetic susceptibility and resistivity measurements to study single-crystal samples of K$_x$Fe$_{2-y}$Se$_2$, which contain the superconducting phase that has a transition temperature ... More
Finiteness of the total first curvature of a non-closed curve in $\mathbb{E}^{n}$Nov 16 2012We consider a regular smooth curve in $\mathbb{E}^n$ such that its coordinates' components are the fundamental solutions of the differential equation $ y^{(n)} (x) - y(x) = 0 ,$ $x \in \mathbb{R} $ of order $n$. We show that the total first curvature ... More
Evolution of Magnetic Double Helix and Quantum Criticality near a Dome of Superconductivity in CrAsJan 08 2019At ambient pressure CrAs undergoes a first-order transition into a double-helical magnetic state at TN = 265 K, which is accompanied by a structural transition. The recent discovery of pressure-induced superconductivity in CrAs makes it important to clarify ... More
Antiferromagnetic Vortex Core of Tl_2Ba_2CuO_{6+x} Studied by Nuclear Magnetic ResonanceMay 22 2003Spatially-resolved NMR is used to probe the magnetism in and around vortex cores of nearly optimally-doped Tl_2Ba_2CuO_{6+x} (Tc=85 K). The NMR relaxation rate 1/T_1 at Tl site provides a direct evidence that the AF spin correlation is significantly enhanced ... More
Field-angle resolved specific heat and thermal conductivity in the vortex phase of UPd_2Al_3Jan 06 2005The field-angle dependent specific heat and thermal conductivity in the vortex phase of UPd_2Al_3 is studied using the Doppler shift approximation for the low energy quasiparticle excitations. We first give a concise presentation of the calculation procedure ... More
How Far Can the SO(10) Two Higgs Model Describe the Observed Neutrino Masses and Mixings ?Aug 24 2001Feb 23 2002Can the SO(10) model with one {\bf 10} and one {\bf 126} Higgs scalars give the observed masses and mixings of quarks and leptons without any other additional Higgs scalars? Recently, at least, for quarks and charged leptons, it has been demonstrated ... More
Precise Measurement of a Magnetic Field Generated by the Electromagnetic Flux Compression TechniqueJan 13 2013The precision of the values of a magnetic field generated by electromagnetic flux compression was investigated in ultra-high magnetic fields of up to 700 T. In an attempt to calibrate the magnetic field measured by pickup coils, precise Faraday rotation ... More
The Overdense Environment of a Large Lyman-alpha Nebula at z~2.7Mar 29 2008Large nebulae (>50 kpc) emitting strongly in Lya (also known as Lya ``blobs'') are likely signposts of ongoing massive galaxy formation. The relative rarity of these sources and their discovery in well-studied galaxy overdensities suggest that they may ... More
Non-Fermi surface nesting driven commensurate magnetic ordering in Fe-doped Sr$_2$RuO$_4$Jan 31 2018Sr$_2$RuO$_4$, an unconventional superconductor, is known to possess an incommensurate spin density wave instability driven by Fermi surface nesting. Here we report a static spin density wave ordering with a commensurate propagation vector $q_c$ = (0.25 ... More
Thermodynamic phase diagram and phase competition in BaFe2(As1-xPx)2 studied by thermal expansionMar 09 2012High-resolution thermal-expansion and specific-heat measurements were performed on single crystalline BaFe2(As1-xPx)2 (0 < x < 0.33, x = 1). The observation of clear anomalies allows to establish the thermodynamic phase diagram which features a small ... More
Itinerant Antiferromagnetism in RuO$_{2}$Dec 30 2016Bulk rutile RuO$_2$ has long been considered a Pauli paramagnet. Here we report that RuO$_2$ exhibits a hitherto undetected lattice distortion below approximately 900 K. The distortion is accompanied by antiferromagnetic order up to at least 300 K with ... More
ALMA Deep Field in SSA22: A concentration of dusty starbursts in a z=3.09 protocluster coreOct 29 2015We report the results of $1^{\prime}.5 \times3^{\prime}$ mapping at 1.1~mm with the Atacama Large Millimeter/submillimeter Array (ALMA) toward the central region of the $z=3.09$ SSA22 protocluster. By combining our source catalog with archival spectroscopic ... More
Cyclotron resonance study of quasiparticle mass and scattering rate in the hidden-order and superconducting phases of URu2Si2Oct 12 2013The observation of cyclotron resonance in ultra-clean crystals of URu2Si2 [S. Tonegawa et al., PRL 109, 036401 (2012)] provides another route besides quantum oscillations to the determination of the bulk electronic structure in the hidden order phase. ... More
Thermal Conductivity of the Pyrochlore Superconductor KOs2O6: Strong Electron Correlations and Fully Gapped SuperconductivityMar 02 2006Jun 07 2006To elucidate the nature of the superconducting ground state of the geometrically frustrated pyrochlore KOs2O6 (Tc=9.6K), the thermal conductivity was measured down to low temperatures (~Tc/100). We found that the quasiparticle mean free path is strikingly ... More
SXDF-UDS-CANDELS-ALMA 1.5 arcmin$^2$ deep surveyJan 02 2016We have conducted 1.1 mm ALMA observations of a contiguous $105'' \times 50''$ or 1.5 arcmin$^2$ window in the SXDF-UDS-CANDELS. We achieved a 5$\sigma$ sensitivity of 0.28 mJy, providing a flat sensus of dusty star-forming galaxies with $L_{\rm IR} \sim6\times10^{11}$ ... More
Thermal conductivity evidence for d_{x^2-y^2} pairing symmetry in the heavy-fermion CeIrIn5 superconductorDec 17 2007Quasi-two dimensional CeIrIn5 contains two distinct domes with different heavy fermion superconducting states in its phase diagram. Here we pinned down the superconducting gap structure of CeIrIn5 in the second dome, located away from the antiferromagnetic ... More
Exotic Superconducting Properties in the Electron-Hole Compensated Heavy Fermion `Semimetal' URu2Si2Aug 08 2007We show that the charge and thermal transport measurements on ultraclean crystals of URu2Si2 reveal a number of unprecedented superconducting properties. The uniqueness is best highlighted by the peculiar field dependence of thermal conductivity including ... More
A Strong Lyman-alpha Emitter at z=6.33 in the Subaru Deep Field Selected as an i' DropoutAug 13 2004We report on the discovery of a star-forming galaxy at z=6.33 in the Subaru Deep Field. This object is selected as a candidate of an i'-dropout, high-redshift galaxy around z=6 because of its red i'-z' color in our deep optical imaging survey in the Subaru ... More
Line nodes in the superconducting gap function of noncentrosymmetric CePt_3SiApr 14 2005The superconducting gap structure of recently discovered heavy fermion CePt_3Si without spatial inversion symmetry was investigated by thermal transport measurements down to 40 mK. In zero field a residual T-linear term was clearly resolved as T-> 0, ... More
One-neutron knockout reaction of 17C on a hydrogen target at 70 MeV/nucleonDec 04 2013Dec 18 2013First experimental evidence of the population of the first 2- state in 16C above the neutron threshold is obtained by neutron knockout from 17C on a hydrogen target. The invariant mass method combined with in-beam gamma-ray detection is used to locate ... More
Giant Nernst effect in a Kondo lattice close to a quantum critical pointNov 20 2003We present a study of Nernst and Seebeck coefficients of the heavy-fermion superconductor CeCoIn$_{5}$. Below 18 K, concomitant with a field-dependent Seebeck coefficient, a large sub-linear Nernst signal emerges with a magnitude drastically exceeding ... More
The ALMA Patchy Deep Survey: A blind search for [CII] emitters at z~4.5May 09 2015We present a result of a blind search for [CII] 158 $\mu$m emitters at $z\sim 4.5$ using ALMA Cycle~0 archival data. We collected extra-galactic data covering at 330-360 GHz (band~7) from 8 Cycle~0 projects from which initial results have been already ... More
Anomalous Temperature Dependence of Lower Critical Field in Ultraclean URu$_2$Si$_2$Sep 06 2009Jul 26 2010To investigate a mysterious superconducting state of URu_2Si_2 embedded in the so-called hidden order state, the lower critical field H_{c1} is precisely determined down to 55 mK for H || a and H || c. For this purpose, the positional dependence of the ... More
Possible Phase Transition Deep Inside the Hidden Order Phase of Ultraclean URu2Si2Mar 23 2009To elucidate the underlying nature of the hidden order (HO) state in heavy-fermion compound URu2Si2, we measure electrical transport properties of ultraclean crystals in a high field/low temperature regime. Unlike previous studies, the present system ... More
Colossal thermomagnetic response in the exotic superconductor URu2Si2Nov 05 2014Nov 06 2014When a superconductor is heated above its critical temperature $T_c$, macroscopic coherence vanishes, leaving behind droplets of thermally fluctuating Cooper pair. This superconducting fluctuation effect above $T_c$ has been investigated for many decades ... More
Flux Line Lattice Melting and the Formation of a Coherent Quasiparticle Bloch State in the Ultraclean URu$_2$Si$_2$ SuperconductorOct 12 2007Dec 16 2007We find that in ultraclean heavy-fermion superconductor URu$_2$Si$_2$ ($T_{c0}=1.45$ K) a distinct flux line lattice melting transition with outstanding characters occurs well below the mean-field upper critical fields. We show that a very small number ... More
Quadratic Gröbner bases arising from partially ordered setsJun 02 2015Oct 07 2015The order polytope $\mathcal{O}(P)$ and the chain polytope $\mathcal{C}(P)$ associated to a partially ordered set $P$ are studied. In this paper, we introduce the convex polytope $\Gamma(\mathcal{O}(P), -\mathcal{C}(Q))$ which is the convex hull of $\mathcal{O}(P) ... More
Gorenstein Fano polytopes arising from order polytopes and chain polytopesJul 12 2015Richard Stanley introduced the order polytope $\mathcal{O}(P)$ and the chain polytope $\mathcal{C}(P)$ arising from a finite partially ordered set $P$, and showed that the Ehrhart polynomial of $\mathcal{O}(P)$ is equal to that of $\mathcal{C}(P)$. In ... More
Induced matching numbers of finite graphs and edge idealsFeb 27 2019Let $G$ be a finite simple graph on the vertex set $V(G) = \{x_1, \ldots, x_n\}$ and $I(G) \subset K[V(G)]$ its edge ideal, where $K[V(G)]$ is the polynomial ring in $x_1, \ldots, x_n$ over a field $K$ with each ${\rm deg} x_i = 1$ and where $I(G)$ is ... More
Cancellation properties in ideal systems: an $\boldsymbol{e.a.b.}$ not $\boldsymbol{a.b.}$ star operationFeb 11 2010Feb 21 2010We show that Krull's \texttt{a.b.} cancellation condition is a properly stronger condition than Gilmer's \texttt{e.a.b.} cancellation condition for star operations.
Strongly Koszul edge ringsOct 28 2013Jan 23 2014We classify the finite connected simple graphs whose edge rings are strongly Koszul. From the classification, it follows that if the edge ring is strongly Koszul, then its toric ideal possesses a quadratic Gr\"obner basis.
Regularity and $h$-polynomials of edge idealsOct 16 2018For any two integers $d,r \geq 1$, we show that there exists an edge ideal $I(G)$ such that the ${\rm reg}\left(R/I(G)\right)$, the Castelnuovo-Mumford regularity of $R/I(G)$, is $r$, and ${\rm deg} (h_{R/I(G)}(t))$, the degree of the $h$-polynomial of ... More
Microscopic Evidence of Direct Coupling between Magnetic and Superconducting Order Parameters in BaFe$_2$(As$_{1-x}$P$_x$)$_2$Nov 30 2011Feb 11 2012The coexistence of magnetism and superconductivity in the isovalent-P-substituted BaFe$_2$(As$_{1-x}$P$_x$)$_2$ has been investigated microscopically by $^{31}$P-NMR measurements. We found that superconducting (SC) transition occurs in a magnetic region ... More
Panoramic Survey of Lyman α Emitters at z=3.1Feb 01 2012Feb 06 2012We present the results of the extensive narrow-band survey of Ly\alpha\ emission-line objects at z=3.1 in the 1.38 deg^2 area surrounding the high density region of star-forming galaxies at z=3.09 in the SSA22 field, as well as in the 1.04 deg^2 area ... More
Free flux flow resistivity in strongly overdoped high-T_c cuprate; purely viscous motion of the vortices in semiclassical d-wave superconductorJun 04 2002We report the free flux flow (FFF) resistivity associated with a purely viscous motion of the vortices in moderately clean d-wave superconductor Bi:2201 in the strongly overdoped regime (T_c=16K) for a wide range of the magnetic field in the vortex state. ... More
Effects of Rattling Phonons on the Quasiparticle Excitation and Dynamics in the Superconducting $β$-Pyrochlore KOs$_2$O$_6$May 17 2007Microwave penetration depth $\lambda$ and surface resistance at 27 GHz are measured in high quality crystals of KOs$_2$O$_6$. Firm evidence for fully-gapped superconductivity is provided from $\lambda(T)$. Below the second transition at $T_{\rm p}\sim ... More
Unusual behaviors in the transport properties of REFe$_{4}$P$_{12}$ (RE: La, Ce, Pr, and Nd)Oct 02 2000We have investigated the resistivity ($\rho$), thermoelectric power (TEP) and Hall coefficient ($R_{H}$) on high quality single crystals of REFe$_{4}$P$_{12}$. TEP in CeFe$_{4}$P$_{12}$ is extremely large ($\sim$ 0.5mV/K at 290K) with a peak of $\sim$ ... More
Abrupt recovery of Fermi-liquid transport by the c-axis collapse in CaFe2(As1-xPx)2 single crystalsDec 05 2010Single crystals of CaFe$_2$(As$_{1-x}$P$_x$)$_2$ are found to exhibit the tetragonal (T) to collapsed-tetragonal (cT) transition at $T_{\rm cT} \lesssim100$\,K for $x>0.05$. The c-axis shrinks by $\sim9$% below $T_{\rm cT}$, which substantially diminishes ... More
Thermoelectric response near a quantum critical point: the case of CeCoIn5Apr 16 2007Oct 09 2007We present a study of thermoelectric coefficients in CeCoIn_5 down to 0.1 K and up to 16 T in order to probe the thermoelectric signatures of quantum criticality. In the vicinity of the field-induced quantum critical point, the Nernst coefficient nu exhibits ... More
Conventional s-wave superconductivity in BiS2-based NdO0.71F0.29BiS2 revealed by thermal transport measurementsJan 14 2016Apr 08 2016To study the superconducting gap structure of BiS$_2$-based layered compound NdO$_{0.71}$F$_{0.29}$BiS$_{2}$ ($T$$_{\rm c}$ = 5 K), we measured the thermal conductivity $\kappa$, which is a sensitive probe of the low-energy quasiparticle spectrum. In ... More
A search for deeply bound kaonic nuclear statesJan 18 2005We have measured proton and neutron energy spectra by stopping negative kaons on liquid helium4. Two distinct peak structures were found on both spectra, which were assigned to the formation of new kinds of strange stribaryons. In this paper, we summarize ... More
Fulde-Ferrell-Larkin-Ovchinnikov state in a perpendicular field of quasi two-dimensional CeCoIn5May 16 2006May 18 2006A Fulde-Ferrell-Larkin-Ovchinnkov (FFLO) state was previously reported in the quasi-2D heavy fermion CeCoIn5 when a magnetic field was applied parallel to the ab-plane. Here, we conduct 115^In NMR studies of this material in a PERPENDICULAR field, and ... More
Field-induced quantum critical route to a Fermi liquid in high-temperature superconductorsMay 15 2008In high transition temperature (T_c) superconductivity, charge doping is a natural tuning parameter that takes copper oxides from the antiferromagnet to the superconducting region. In the metallic state above T_c the standard Landau's Fermi-liquid theory ... More
Single crystal growth and physical properties of a new uranium compound URhIn$_5$Jul 16 2013We have grown the new uranium compound URhIn$_5$ with the tetragonal HoCoGa$_5$-type by the In self flux method. In contrast to the nonmagnetic ground state of the isoelectronic analogue URhGa$_5$, URhIn$_5$ is an antiferromagnet with antiferromagnetic ... More
Superconducting gap structure of BaFe_2(As_{1-x}P_{x})_2Sep 26 2014We present a study of the superconducting gap structure in the iron-pnictide series BaFe2(As1-xPx)2. By measuring the variation of the specific heat as a function of temperature and magnetic field we are able to determine the number and Fermi surface ... More
Isoscalar Giant Monopole, Dipole, and Quadrupole Resonances in $^{90,92}$Zr and $^{92}$MoJun 14 2018The isoscalar giant monopole, dipole, and quadrupole strength distributions have been deduced in $^{90, 92}$Zr, and $^{92}$Mo from "background-free" spectra of inelastic $\alpha$-particle scattering at a beam energy of 385 MeV at extremely forward angles, ... More
$Λd$ correlations from the $^4$He(stopped-$K^-$,$d$) reactionSep 07 2007Dec 22 2007We have observed an intense high-energy component in an inclusive $^4$He(stopped $K^-$, $d$) spectrum. For back-to-back $\Lambda d$ pairs a prominent event cluster has been found just below the $m_{^4\textrm{He}}+m_{K^-}-m_{n}$ mass threshold in the $\Lambda ... More
Coexisting localized and itinerant gapless excitations in a quantum spin liquid candidate 1T-TaS$_2$Mar 16 2018To reveal the nature of elementary excitations in a quantum spin liquid (QSL), we measured low temperature thermal conductivity and specific heat of 1T-TaS$_2$, a QSL candidate material with frustrated triangular lattice of spin-1/2. The nonzero temperature ... More
Highly Anisotropic Superconducting Gap in Nematically Ordered and Tetragonal Phases of FeSe$_{1-x}$S$_x$May 25 2017FeSe has a unique ground state in which superconductivity coexists with a nematic order without long-range magnetic ordering at ambient pressure. Here, to study how the pairing interaction evolves with nematicity, we measured the thermal conductivity ... More
Search for Antihelium with the BESS-Polar SpectrometerJan 13 2012In two long-duration balloon flights over Antarctica, the BESS-Polar collaboration has searched for antihelium in the cosmic radiation with higher sensitivity than any reported investigation. BESS- Polar I flew in 2004, observing for 8.5 days. BESS-Polar ... More
Normal-state Hall Angle and Magnetoresistance in quasi-2D Heavy Fermion CeCoIn_5 near a Quantum Critical PointMay 09 2003The normal-state Hall effect and magnetoresisitance (MR) have been measured in the quasi-2D heavy fermion superconductor CeCoIn_5. In the non-Fermi liquid region where the reistivity rho_xx exhibits an almost perfect T-linear dependence, the Hall angle ... More
Diffuse Lyman Alpha Haloes around Lyman Alpha Emitters at z=3: Do Dark Matter Distributions Determine the Lyman Alpha Spatial Extents?Apr 22 2012Using stacks of Ly-a images of 2128 Ly-a emitters (LAEs) and 24 protocluster UV-selected galaxies (LBGs) at z=3.1, we examine the surface brightness profiles of Ly-a haloes around high-z galaxies as a function of environment and UV luminosity. We find ... More
Anisotropic Superconducting Properties of Optimally Doped BaFe$_2$(As$_{0.65}$P$_{0.35}$)$_2$ under PressureJun 30 2010Sep 02 2010Magnetic measurements on optimally doped single crystals of BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$ ($x\approx0.35$) with magnetic fields applied along different crystallographic axes were performed under pressure, enabling the pressure evolution of coherence ... More
CeLAND: search for a 4th light neutrino state with a 3 PBq 144Ce-144Pr electron antineutrino generator in KamLANDDec 03 2013Apr 13 2014The reactor neutrino and gallium anomalies can be tested with a 3-4 PBq (75-100 kCi scale) 144Ce-144Pr antineutrino beta-source deployed at the center or next to a large low-background liquid scintillator detector. The antineutrino generator will be produced ... More
Measurement of cosmic-ray low-energy antiproton spectrum with the first BESS-Polar Antarctic flightMay 12 2008Sep 21 2008The BESS-Polar spectrometer had its first successful balloon flight over Antarctica in December 2004. During the 8.5-day long-duration flight, almost 0.9 billion events were recorded and 1,520 antiprotons were detected in the energy range 0.1-4.2 GeV. ... More
High field x-ray diffraction study on a magnetic-field-induced valence transition in YbInCu4Aug 10 2005We report the first high-field x-ray diffraction experiment using synchrotron x-rays and pulsed magnetic fields exceeding 30 T. Lattice deformation due to a magnetic-field-induced valence transition in YbInCu4 is studied. It has been found that the Bragg ... More
Direct observation of lattice symmetry breaking at the hidden-order transition in URu2Si2Jun 19 2014Since the 1985 discovery of the phase transition at $T_{\rm HO}=17.5$ K in the heavy-fermion metal URu$_2$Si$_2$, neither symmetry change in the crystal structure nor magnetic ordering have been observed, which makes this "hidden order" enigmatic. Some ... More
Exotic Heavy Fermion State in the Filled Skutterudite PrFe$_4$P$_{12}$ Uncovered by the de Haas-van Alphen EffectSep 30 2000Aug 19 2002We report the de Haas-van Alphen (dHvA) experiment on the filled skutterudite PrFe$_4$P$_{12}$ exhibiting apparent Kondo-like behaviors in the transport and thermal properties. We have found enormously enhanced cyclotron effective mass $m^{\rm \ast}_{\rm ... More