Results for "Kazumi Ozaki"

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Rethinking CO Antibiosignatures in the Search for Life Beyond the Solar SystemMar 18 2019Some atmospheric gases have been proposed as counter indicators to the presence of life on an exoplanet if remotely detectable at sufficient abundance (i.e., antibiosignatures), informing the search for biosignatures and potentially fingerprinting uninhabited ... More
N=4 SYM on K3 and the AdS(3)/CFT(2) CorrespondenceJan 08 2008Jan 30 2008We study the Fareytail expansion of the topological partition function of N=4 SU(N) super Yang-Mills theory on K3. We argue that this expansion corresponds to a sum over geometries in asymptotically AdS_3 spacetime, which is holographically dual to a ... More
Ratio of Tensions from Vacuum String Field TheoryJan 17 2002Mar 26 2002We show analytically that the ratio of the norm of sliver states agrees with the ratio of D-brane tensions. We find that the correct ratio appears as a twist anomaly.
D-Branes on the Null-BraneNov 22 2002Nov 27 2002We study D-branes in the null-brane background. Using the covariant formalism of the worldsheet theory, we construct the boundary states describing D-branes on the null-brane. From the cylinder amplitudes, we find that the D-branes with codimension zero ... More
Ghost Kinetic Operator of Vacuum String Field TheoryJan 03 2002Jan 10 2002Using the data of eigenvalues and eigenvectors of Neumann matrices in the 3-string vertex, we prove analytically that the ghost kinetic operator of vacuum string field theory obtained by Hata and Kawano is equal to the ghost operator inserted at the open ... More
Wilson loops in 3d $\mathcal{N}=4$ SQCD from Fermi gasOct 07 2016We study 1/2 BPS Wilson loops in 3d $\mathcal{N}=4$ $U(N)$ Yang-Mills theory with one adjoint and $N_f$ fundamental hypermultiplets from the Fermi gas approach. By numerical fitting, we find the first few worldsheet instanton corrections to the Wilson ... More
Probing non-perturbative effects in M-theory on orientifoldsNov 09 2015Using holography, we study non-perturbative effects in M-theory on orientifolds from the analysis of the S^3 partition functions of dual field theories. We consider the S^3 partition functions of N=4 Yang-Mills theory with O(n) gauge symmetry coupled ... More
Wess-Zumino Term in Tachyon Effective ActionApr 10 2003Apr 16 2003We show that the source of RR field computed from the boundary state describing the decay of a non-BPS brane is reproduced by a particular form of the Wess-Zumino term in the tachyon effective action. We also obtain a simple expression of the S-charge ... More
Anisotropic ground states of the quantum Hall system with currentsJan 10 2009Anisotropic states at half-filled third and higher Landau levels are investigated in the system with a finite electric current. We study the response of the striped Hall state and the anisotropic charge density wave (ACDW) state against the injected current ... More
Linear Sigma Models for the R^8/Z_k OrbifoldJul 01 2008Jul 20 2008We construct N=4 gauged linear sigma models in two dimensions whose Higgs branch has a R^8/Z_k orbifold singularity or its generalization. Our linear sigma models have either ALF or ALE type hyperKahler 8-manifolds as their Higgs branch. For the ALE case, ... More
Instanton Corrections of 1/6 BPS Wilson Loops in ABJM TheoryJul 21 2016Jul 22 2016We study instanton corrections to the vacuum expectation value (VEV) of 1/6 BPS Wilson loops in ABJM theory from the Fermi gas approach. We mainly consider Wilson loops in the fundamental representation and winding Wilson loops, but we also initiate the ... More
Linear Sigma Models of H and KK MonopolesAug 15 2005Aug 23 2005We propose a gauged linear sigma model of k H-monopoles. We also consider the T-dual of this model describing KK-monopoles and clarify the meaning of "winding coordinate" studied recently in hep-th/0507204.
Orientifolding of the ABJ Fermi gasJan 13 2016Mar 03 2016The grand partition functions of ABJ theory can be factorized into even and odd parts under the reflection of fermion coordinate in the Fermi gas approach. In some cases, the even/odd part of ABJ grand partition function is equal to that of $\mathcal{N}=5$ ... More
q-Deformed Oscillators and D-branes on ConifoldJan 15 2009Jan 20 2009We study the q-deformed oscillator algebra acting on the wavefunctions of non-compact D-branes in the topological string on conifold. We find that the mirror B-model curve of conifold appears from the commutation relation of the q-deformed oscillators. ... More
Instanton Solution in Tachyon CosmologyMay 23 2007We find an exact classical solution in Euclidean gravity coupled to a scalar field with a particular form of potential commonly used in tachyon cosmology. This solution represents a tunneling between two vacua.
D-Brane Amplitudes in Topological String on ConifoldJun 06 2006Jun 08 2006We study the relation between two kinds of topological amplitudes of non-compact D-branes on conifold. In the A-model, D-branes are represented by fermion operators in the melting crystal picture and the amplitudes are given by the quantum dilogarithm. ... More
Noncommutative Tachyon from Background Independent Open String Field TheoryOct 05 2000Oct 26 2000We analyze the tachyon field in the bosonic open string theory in a constant B-field background using the background independent open string field theory. We show that in the large noncommutativity limit the action of tachyon field is given exactly by ... More
Boundary States in B-Field BackgroundSep 27 2000Jan 05 2001We consider the boundary states which describe D-branes in a constant B-field background. We show that the two-form field Phi, which interpolates commutative and noncommutative descriptions of D-branes, can be interpreted as the invariant field strength ... More
A Path Integral Representation of the Map between Commutative and Noncommutative Gauge FieldsOct 18 1999Aug 28 2000The world-volume theory on a D-brane in a constant B-field background can be described by either commutative or noncommutative Yang-Mills theories. These two descriptions correspond to two different gauge fixing of the diffeomorphism on the brane. Comparing ... More
D1-D5 on ALE SpaceOct 24 2005Oct 26 2005We construct a two-dimensional N=(0,4) quiver gauge theory on D1-brane probing D5-branes on ALE space, and study its IR behavior. This can be thought of as a gauged linear sigma model for the NS5-branes on ALE space.
Comments on Half S-BranesAug 26 2003Sep 02 2003Following hep-th/0305177, we write the boundary state of half S-brane in bosonic string theory as a grand canonical partition function of a unitary matrix model. From this representation, it follows that the annulus amplitude can be written as a grand ... More
Comments on Open Wilson Lines and Generalized Star ProductsJan 26 2001Feb 05 2001We consider an open Wilson line as a momentum representation of a boundary state which describes a D-brane in a constant B-field background. Using this picture, we study the Seiberg-Witten map which relates the commutative and noncommutative gauge fields, ... More
On the abelian groups which occur as Galois cohomology groups of global unit groupsFeb 06 2013For any finite group G and integer i, let $\mathcal{H}^i(G)$ be the set of all the isomorphism classes of the Galois cohomology groups $\hat{H}^i(K/k,E_K)$, where K/k runs over all the unramified G-extension of number fields and E_K denotes the global ... More
Kinematic and Excitation Structure of the NGC 1068 Narrow-Line RegionJan 13 2009We investigated the kinematic and excitation structure of the NGC 1068 narrow-line region (NLR). We obtained profiles of several emission lines, [OIII]$\lambda$5007, H$\beta$, [OI]$\lambda$6300 and [FeVII]$\lambda$6087 at high-velocity resolution (R ~ ... More
Galaxy Mergers as a Source of Cosmic Rays, Neutrinos, and Gamma RaysMay 13 2014Jul 09 2014We investigate the shock acceleration of particles in massive galaxy mergers or collisions, and show that cosmic rays (CRs) can be accelerated up to the second knee energy ~0.1-1 EeV and possibly beyond, with a hard spectral index Gamma ~ 2. Such CRs ... More
On a Lorentz covariant matrix regularization of membrane theoriesJun 04 1997A Lorentz covariant matrix regularization of membrane thories is studied.It is shown that the action for a bosonic membrane can be defined by matrix regularization in a Lorentz covariant manner. The generator of area preserving diffeomorphism can also ... More
Open String Fields As MatricesMay 14 2001Jul 06 2001We present a new representation of the string vertices of the cubic open string field theory. By using this three-string vertex, we attempt to identify open string fields as huge-sized matrices by following Witten's idea. By using these huge matrices, ... More
Matrix Theory on Noncommutative TorusMar 05 1998Mar 30 1998We consider the compactification of Matrix theory on tori with background antisymmetric tensor field. Douglas and Hull have recently discussed how noncommutative geometry appears on the tori. In this paper, we demonstrate the concrete construction of ... More
Phason modes in spin-density wave in the presence of long-range Coulomb interactionNov 24 1993We study the effect of long-range Coulomb interaction on the phason in spin-density wave (SDW) within mean field theory. In the longitudinal limit and in the absence of SDW pinning the phason is completely absorbed by the plasmon due to the Anderson-Higgs ... More
$α'$-expansion of Anti-Symmetric Wilson Loops in $\mathcal{N}=4$ SYM from Fermi GasJul 06 2016Sep 27 2016We study the large 't Hooft coupling expansion of 1/2 BPS Wilson loops in the anti-symmetric representation in $ \mathcal{N}=4 $ super Yang-Mills (SYM) theory at the leading order in the 1/N expansion. Via AdS/CFT correspondence, this expansion corresponds ... More
BRST gauge fixing and the algebra of global supersymmetryAug 04 1997Jan 19 1998A global supersymmetry (SUSY) in supersymmetric gauge theory is generally broken by gauge fixing. A prescription to extract physical information from such SUSY algebra broken by gauge fixing is analyzed in path integral framework. If $\delta_{SUSY}\delta_{BRST}\Psi ... More
Exact results for ABJ Wilson loops and open-closed dualityMar 21 2016We find new exact relations between the partition function and vacuum expectation values (VEVs) of 1/2 BPS Wilson loops in ABJ theory, which allow us to predict the large N expansions of the 1/2 BPS Wilson loops from known results of the partition function. ... More
Exact results on ABJ theory and the refined topological stringMay 14 2014Jul 22 2014We study the partition function of the ABJ theory, which is the N=6 superconformal Chern-Simons matter theory with gauge group U(N)xU(N+M) and Chern-Simons levels (k,-k). We exactly compute the ABJ partition function on a three sphere for various k, M ... More
TBA-like integral equations from quantized mirror curvesDec 21 2015Jan 15 2016Quantizing the mirror curve of certain toric Calabi-Yau (CY) three-folds leads to a family of trace class operators. The resolvent function of these operators is known to encode topological data of the CY. In this paper, we show that in certain cases, ... More
Construction of maximal unramified p-extensions with prescribed Galois groupsMay 16 2007Jul 17 2009In the present paper, we shall show that for any prime number p, every finite p-group occurs as the Galois Group of the maximal unramified p-extension over a certain number field of finite degree. We shall also show that for any given pro-p-group G with ... More
Remark on the Alexander polynomials of periodic knotsJan 25 2010We will show that if $K$ is a knot of prime period $p>2$ and whose Alexander polynomial $\Delta_K(t)$ is monic and of degree $p-1$, then $\Delta_K(t)$ is uniquely determined only by $p$.
Numerically exact O($N^{7/3}$) method for large-scale electronic structure calculationsMay 01 2010An efficient low-order scaling method is presented for large-scale electronic structure calculations based on the density functional theory using localized basis functions, which directly computes selected elements of the density matrix by a contour integration ... More
Numerical Analysis of Coleman-de Luccia TunnelingJan 28 2016Feb 08 2016We study the false vacuum decay of a single scalar field $\phi$ coupled to gravity described by the Coleman-de Luccia (CdL) instanton. We show that it is possible to numerically calculate the bounce factor, which is related to the CdL tunneling rate, ... More
Fractional Strings in (p,q) 5-brane and Quiver Matrix String TheoryMay 30 1998We study the (p,q)5-brane dynamics from the viewpoint of Matrix string theory in the T-dualized ALE background. The most remarkable feature in the (p,q)5-brane is the existence of ``fractional string'', which appears as the instanton of 5-brane gauge ... More
BPS Condition of String Junction from M theoryDec 07 1997We give a simple derivation of BPS condition of string junction from M theory
Resummations and Non-Perturbative CorrectionsMay 27 2015Jun 04 2016We consider a generalization of the Borel resummation, which turns out to be equivalent to the standard Borel resummation. We apply it to the simplest large N duality between the pure Chern-Simons theory and the topological string on the resolved conifold, ... More
Enhanced exploration for primordial black holes using pulsar timing arraysAug 20 2012We investigate the capability of pulsar timing arrays (PTAs) as a probe of primordial black holes (PBHs), which might constitute the Galactic dark matter. A PBH passing nearby the Earth or a pulsar gives an impulse acceleration and induces residuals on ... More
Quasi-particle spectrum around a single vortex in s-wave superconductorsOct 15 1998Making use of the Bogoliubov-de Gennes equation, we study the quasi-particle spectrum and the vortex core structure of a single vortex in quasi 2D s-wave superconductors for small $p_F\xi_0$, where $p_F$ is the Fermi momentum and $\xi_0=v_F/\Delta_0$ ... More
Bound states and extended states around a single vortex in the d-wave superconductorsNov 10 2000Making use of the Bogoliubov-de Gennes equation for the d-wave superconductors, we investigate the quasi-particle spectrum around a single vortex. Taking $p_F\xi=10$, we found that there are bound states which are localized around the vortex core, and ... More
$α'$-expansion of Anti-Symmetric Wilson Loops in $\mathcal{N}=4$ SYM from Fermi GasJul 06 2016Sep 29 2016We study the large 't Hooft coupling expansion of 1/2 BPS Wilson loops in the anti-symmetric representation in $ \mathcal{N}=4 $ super Yang-Mills (SYM) theory at the leading order in the 1/N expansion. Via AdS/CFT correspondence, this expansion corresponds ... More
Stellar Tidal Disruption Events by Direct Collapse Black HolesFeb 13 2016Jun 23 2016We analyze the early growth stage of direct-collapse black holes (DCBHs) with $\sim 10^{5} \ \rm M_\odot$, which are formed by collapse of supermassive stars in atomic-cooling halos at $z \gtrsim 10$. A nuclear accretion disk around a newborn DCBH is ... More
String Network and 1/4 BPS States in N=4 SU(n) Supersymmetric Yang-Mills TheoryApr 21 1998Apr 27 1998We construct the classical configurations of BPS states with 1/4 unbroken supersymmetries in four-dimensional N=4 SU(n+1) supersymmetric Yang-Mills theory, and discuss that these configurations correspond to string networks connecting (n+1) D3-branes ... More
Parameter study of the diamagnetic relativistic pulse accelerator (DRPA) in slab geometry I: Dependence on initial frequency ratio and slab widthAug 08 2003Two-and-a-half-dimensional particle-in-cell plasma simulations are used to study the particle energization in expanding magnetized electron-positron plasmas with slab geometry. When the magnetized relativistic plasma with high temperature (initial electron ... More
Efficient Recursion Method for Inverting Overlap MatrixJun 04 2001A new O(N) algorithm based on a recursion method, in which the computational effort is proportional to the number of atoms N, is presented for calculating the inverse of an overlap matrix which is needed in electronic structure calculations with the the ... More
SO(9,1) invariant matrix formulation of supermembraneSep 05 1997An $SO(9,1)$ invariant formulation of an 11-dimensional supermembrane is presented by combining an $SO(10,1)$ invariant treatment of reparametrization symmetry with an $SO(9,1)$ invariant $\theta_{R} = 0$ gauge of $\kappa$-symmetry. The Lagrangian thus ... More
Quasi-Particle Spectrum around a Single Vortex in Superconductors - s-Wave Case -Apr 21 2000Making use of the Bogoliubov-de Gennes equation, we study the quasi-particle spectrum and the vortex core structure of a single vortex in quasi 2D s-wave superconductors for small p_F xi_0, where p_F is the Fermi momentum and xi_0=v_F/Delta_0 is the coherence ... More
Comma Vertex and String Field AlgebraJul 12 2001Jul 23 2001We study the matter part of the algebra of open string fields using the 3-string vertex over the sliver state, which we call ``comma vertex''. By generalizing this comma vertex to the $N$-string overlap, we obtain a closed form of the Neumann coefficients ... More
Hairpin Branes and D-Branes Behind the HorizonFeb 06 2006We study Lorentzian D-particles in linear dilaton and the two dimensional black hole backgrounds. The D-particle trajectory follows an accelerated trajectory which is smeared by stringy corrections. For the black hole background we find that the portion ... More
Repeated Bifurcation of Relativistic Magnetic Pulse and Cosmic Gamma-Ray BurstsAug 18 2003The diverse and complex light curves of gamma-ray bursts (GRBs) remain an outstanding astrophysical mystery. Here we report the results of 2-1/2-dimensional particle-in-cell (PIC) simulations of the relativistic expansion of magnetized electron-positron ... More
Three-Point Functions in N=4 SYM Theory at One-LoopApr 23 2004Sep 21 2004We analyze the one-loop correction to the three-point function coefficient of scalar primary operators in N=4 SYM theory. By applying constraints from the superconformal symmetry, we demonstrate that the type of Feynman diagrams that contribute depends ... More
Half quantum vortex in superfluid $^3$He-A phase in parallel plate geometryFeb 14 2007Jun 05 2007The half quantum vortex(HQV) in condensate has been studied, since it was predicted by Salomaa and Volovik in superfluid $^3$He-A phase. However, an experimental evidence for its existence has not been reported so far. Motivated by a recent experimental ... More
Lüscher's finite size method with twisted boundary conditions: an application to $J/ψ$-$φ$ system to search for narrow resonanceNov 23 2012Jan 18 2013We investigate an application of twisted boundary conditions for study of low-energy hadron-hadron interactions with L\"ushcer's finite size method. It allows us to calculate the phase shifts for elastic scattering of two hadrons at any small value of ... More
New Steps on the Exact Learning of CNFSep 10 2016A major problem in computational learning theory is whether the class of formulas in conjunctive normal form (CNF) is efficiently learnable. Although it is known that this class cannot be polynomially learned using either membership or equivalence queries ... More
Convergent recursive O(N) calculations for ab initio tight-bindingJun 04 2001A theory is presented for a novel recursion method for O(N) ab initio tight-binding calculations. A long-standing problem of generalizing the recursion method to a non-orthogonal basis, which is a crucial step to make the recursion method applicable to ... More
Learning Ontologies with Epistemic Reasoning: The EL CaseFeb 08 2019We investigate the problem of learning description logic ontologies from entailments via queries, using epistemic reasoning. We introduce a new learning model consisting of epistemic membership and example queries and show that polynomial learnability ... More
Fermi/non-Fermi mixing in SU($N$) Kondo effectNov 22 2016We apply conformal field theory analysis to the $k$-channel SU($N$) Kondo system, and find a peculiar behavior in the cases $N > k > 1$, which we call Fermi/non-Fermi mixing: The low temperature scaling is described as the Fermi liquid, while the zero ... More
A method to identify the companion stars of type Ia supernovae in young supernova remnantsFeb 27 2006We propose a method to identify the companion stars of type Ia supernovae (SNe Ia) in young supernova remnants (SNRs) by recognizing distinct features of absorption lines due to Fe I appearing in the spectrum. If a sufficient amount of Fe I remains in ... More
Consequence-Based Axiom PinpointingMay 25 2018Axiom pinpointing refers to the problem of finding the axioms in an ontology that are relevant for understanding a given entailment or consequence. One approach for axiom pinpointing, known as glass-box, is to modify a classical decision procedure for ... More
Instanton Effects in ABJM Theory from Fermi Gas ApproachNov 06 2012Nov 19 2012We study the instanton effects of the ABJM partition function using the Fermi gas formalism. We compute the exact values of the partition function at the Chern-Simons levels k=1,2,3,4,6 up to N=44,20,18,16,14 respectively, and extract non-perturbative ... More
Unconventional Density Waves in Organic Conductors and in SuperconductorsMar 30 2006Unconventional density waves (UDW) are one of the ground states in metallic crystalline solids and have been speculated already in 1968. However, more focused studies on UDW started only recently, perhaps after the identification of the low temperature ... More
Imperfect nesting and transport properties in unconventional density wavesSep 12 2002We consider the effect of imperfect nesting in quasi-one dimensional unconventional density waves. The phase diagram is very close to those in a conventional DW. The linear and non-linear aspects of the electric conductivity are discussed. At T=0 the ... More
Optical conductivity of d-wave superconductorsDec 12 2000We study theoretically the optical conductivity of d-wave superconductors like in high temperature cuprates in the presence of impurities. We limit ourselves at T=0K and focus on the frequency dependence of both sigma_1(omega) and \omega*\sigma_2(omega) ... More
Gauge-Higgs Unification In Spontaneously Created Fuzzy Extra DimensionsAug 23 2011Sep 05 2011We propose gauge-Higgs unification in fuzzy extra dimensions as a possible solution to the Higgs naturalness problem. In our approach, the fuzzy extra dimensions are created spontaneously as a vacuum solution of certain four-dimensional gauge theory. ... More
Threshold electric field in unconventional density wavesJan 22 2001As it is well known most of charge density wave (CDW) and spin density wave (SDW) exhibit the nonlinear transport with well defined threshold electric field E_T. Here we study theoretically the threshold electric field of unconventional density waves. ... More
The magnetic field dependence of the threshold electric field in unconventional charge density wavesMay 02 2001Many experiments suggest that the unidentified low temperature phase (LTP) of alpha-(BEDT-TTF)_2KHg(SCN)_4 is most likely unconventional charge density wave (UCDW). To further this identification we present our theoretical study of the threshold electric ... More
On the neutrino non-detection of GRB 130427AMay 26 2013Jun 16 2013The recent gamma-ray burst GRB 130427A has an isotropic electromagnetic energy $E^{iso}\sim10^{54}$ erg, suggesting an ample supply of target photons for photo-hadronic interactions, which at its low redshift of $z\sim0.34$ would appear to make it a promising ... More
Vortex lattice transition in D-wave superconductorsSep 29 1997Oct 03 1997Making use of the extended Ginzburg Landau theory, which includes the fourth order derivative term, we study the vortex state in a magnetic field parallel to the $ c$ axis. The vortex core structure is distorted due to this higher order term, which reveals ... More
Exact Instanton Expansion of ABJM Partition FunctionJul 07 2015We review recent progress in determining the partition function of the ABJM theory in the large N expansion, including all of the perturbative and non-perturbative corrections. Especially, we will focus on how these exact expansions are obtained from ... More
Instanton Bound States in ABJM TheoryJan 22 2013Feb 18 2013The partition function of the ABJM theory receives non-perturbative corrections due to instanton effects. We study these non-perturbative corrections, including bound states of worldsheet instantons and membrane instantons, in the Fermi-gas approach. ... More
Free Field Appoach to String Theory on AdS_3Sep 14 2000Jan 19 2001We discuss the correlation functions of the SL(2,C)/SU(2) WZW model, or the CFT on the Euclidean AdS_3. We argue that their calculation is reduced to that of a free theory by taking into account the renormalization and integrating out a certain zero-mode, ... More
Bottom-up approach to high-temperature superconductivitySep 22 2006Since the discovery of high-temperature superconductivity in the cuprates a theoretical understanding of their phase diagram has remained one of the major outstanding problems in condensed matter physics. Here we propose an effective low-energy Hamiltonian ... More
Anisotropic superconductivity in PrOs4Sb12Jul 09 2004Oct 08 2005Recently the superconducting gap functions of the skutterudite PrOs$_4$Sb$_{12}$ have been proposed [K. Maki et al, Europhys. Lett. {\bf 68}, 720 (2004)]. The superconductivity is spin-triplet and consists of at least 2 distinct phases in a magnetic field, ... More
Monitoring near-surface depth profile of residual stress in weakly anisotropic media by Rayleigh-wave dispersionOct 12 2016Herein we study the inverse problem on inferring depth profile of near-surface residual stress in a weakly anisotropic medium by boundary measurement of Rayleigh-wave dispersion if all other relevant material parameters of the elastic medium are known. ... More
Unconventional spin density wave in (TMTSF)2PF6 below T* ~ 4KFeb 19 2002Jul 16 2002The presence of subphases in spin-density wave (SDW) phase of (TMTSF)2PF6 below T* ~ 4K has been suggested by several experiments but the nature of the new phase is still controversial. We have investigated the temperature dependence of the angular dependence ... More
Supercurrent in Nodal SuperconductorsMay 11 2004Aug 31 2004In recent years, a number of nodal superconductors have been identified; d-wave superconductors in high T_c cuprates, CeCoIn$_5$, and \kappa-(ET)_2Cu(NCS)_2, 2D f-wave superconductor in Sr_2RuO_4 and hybrid s+g-wave superconductor in YNi_2B_2C. In this ... More
Resonance Impurity Scattering in PrOs$_{4}$Sb$_{12}$Apr 20 2006We study the effect of impurity scattering in the unitarity limit on the A and B phase superconductivity in PrOs4Sb12. We take the triplet superconducting order parameters and the impurity scattering is treated within the standard theory. We find the ... More
Path Integral Approach to String Theory on AdS_3May 17 2000Aug 17 2000Using the path integral approach, we discuss the correlation functions of the $SL(2,\bfC)/SU(2)$ WZW model, which corresponds to the string theory on the Euclidean $AdS_3$. We obtain the two- and three-point functions for generic primary fields in closed ... More
Subphotospheric Neutrinos from Gamma-Ray Bursts: The Role of NeutronsJan 17 2013Sep 27 2013Relativistic outflows with neutrons inevitably lead to inelastic collisions, and resulting subphotospheric gamma rays may explain prompt emission of gamma-ray bursts. In this model, hadronuclear, quasithermal neutrinos in the 10-100 GeV range should be ... More
PP-Waves and HolographyApr 02 2002Apr 02 2002We consider aspects of holography in the $pp$-wave limit of $AdS_5\times S5$. This geometry contains two $\RR4$'s, one obtained from $AdS_5$ directions, and the other from the $S 5$. We argue that the holographic direction in the $pp$-wave background ... More
Magnetotransport in d-wave density wavesSep 19 2005Angle dependent magnetoresistance (ADMR) and giant Nernst effect are hallmarks of unconventional density waves (UDW). Here these transport properties for d-wave density wave (d-DW) are computed for quasi-two-dimensional systems. The present theory describes ... More
Aspects of unconventional density wavesJun 23 2003Recently many people discuss unconventional density waves (i.e. unconventional charge density waves (UCDW) and unconventional spin density waves (USDW)). Unlike in conventional density waves, the quasiparticle spectrum in these systems is gapless. Also ... More
Impurity effects in unconventional density waves in the unitary limitFeb 18 2003We investigate the effect of strong, nonmagnetic impurities on quasi-one-dimensional conventional and unconventional density waves (DW and UDW). The conventional case remains unaffected similarly to s-wave superconductors in the presence of weak, nonmagnetic ... More
Optical conductivity of superconducting Sr_2RuO_4Jan 21 2003We compute the optical conductivity of 2D f-wave superconductors and also of the multigap model proposed recently by Zhitomirsky and Rice at T=0K in the Born limit. The presence of interband impurity scattering was found to play an important role: the ... More
Out of plane optical conductivity in d-wave superconductorsFeb 12 2001We study theoretically the out of plane optical conductivity of d-wave superconductors in the presence of impurities at T=0K. Unlike the usual approach, we assume that the interlayer quasi-particle transport is due to coherent tunneling. The present model ... More
Cosmological Fast Radio Bursts from Binary White Dwarf MergersJul 29 2013Oct 13 2013Recently, Thornton et al. reported the detection of four fast radio bursts (FRBs). The dispersion measures indicate that the sources of these FRBs are at cosmological distance. Given the large full sky event rate ~ 10^4 sky^-1 day^-1, the FRBs are a promising ... More
Exact Results on the ABJM Fermi GasJul 18 2012We study the Fermi gas quantum mechanics associated to the ABJM matrix model. We develop the method to compute the grand partition function of the ABJM theory, and compute exactly the partition function Z(N) up to N=9 when the Chern-Simons level k=1. ... More
Half quantum vortices and Majorana fermions in triplet superconductorsNov 06 2007Half quantum vortices (HQVs) in superfluid $^3He-A$ have been speculated since 1976. Two years ago, Yamashita et al reported a very unusual NMR satellite in the rotating superfluid $^3He-A$ in a parallel plate geometry. Recently this satellite has been ... More
Quasiparticle spectrum of the hybrid s+g-wave superconductors YNi_2B_2C and LuNi_2B_2CSep 29 2003Recent experiments on single crystals of YNi$_2$B$_2$C have revealed the presence of point nodes in the superconducting energy gap Delta(k} at k = (1,0,0), (0,1,0), (-1,0,0), and (0,-1,0). In this paper we investigate the effects of impurity scattering ... More
A Burst in a Wind Bubble and the Impact on Baryonic Ejecta: High-Energy Gamma-Ray Flashes and Afterglows from Fast Radio Bursts and Pulsar-Driven Supernova RemnantsMar 29 2016Jun 03 2016Tenuous wind bubbles, which are formed by the spin-down activity of central compact remnants, are relevant in some models of fast radio bursts (FRBs) and super-luminous supernovae. We study their high-energy signatures, focusing on the role of pair-enriched ... More
Neutron-Proton-Converter Acceleration Mechanism at Subphotospheres of Relativistic OutflowsApr 07 2013Oct 13 2013We study a type of particle acceleration that operates via neutron-proton conversion in inelastic nuclear collisions. This mechanism can be expected for relativistic shocks at subphotospheres if relativistic outflows contain neutrons. Using a test-particle ... More
Magnetoresistance in the SDW state of (TMTSF)2PF6 above T*~4K; Novel effect due to the Landau quantizationMar 12 2002Magnetoresistance in the spin-density wave (SDW) state of (TMTSF)2PF6 is known to exhibit a rich variety of the angular dependencies when a magnetic field B is rotated in the b'-c*, a-b' and a-c* planes. In the presence of a magnetic field the quasiparticle ... More
Recent Advances in Unconventional Density WavesJul 26 2004Unconventional density wave (UDW) has been speculated as a possible electronic ground state in excitonic insulator in 1968. Recent surge of interest in UDW is partly due to the proposal that the pseudogap phase in high T_c cuprate superconductors is d-wave ... More
Impurity scattering in unconventional density wavesMar 21 2002We have investigated the effect of nonmagnetic impurities on the quasi-one-dimensional unconventional density wave (UDW) ground state. The thermodynamics were found to be close to those of a d-wave superconductor in the Born limit. Four different optical ... More
Impurity scattering and frequency dependent conductivity in spin density wavesJun 09 1999The quasiparticle contribution to the frequency dependent electric conductivity in the presence of randomly distributed impurities is calculated within mean field theory for spin density waves as formed in quasi one dimensional conductors like Bechgaard ... More
Charge separation effects in magnetized electron-ion plasma expansion into a vacuumJul 25 2003Charge separation effects in the expansion of magnetized relativistic electron-ion plasmas into a vacuum are examined using 2-1/2-dimensional particle-in-cell plasma simulations. The electrostatic field at the plasma surface decelerates electrons and ... More