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Efficient computation of permanents, with applications to boson sampling and random matricesApr 12 2019In order to verify the results of Boson sampling experiments one must be able to compute the permanent of the associated Hamiltonians. Here we first present a freely available software package, available in both serial and parallel versions. As part of ... More

Complete graph asymptotics for the Ising and random cluster models on 5D grids with cyclic boundaryAug 09 2014The finite size scaling behaviour for the Ising model in five dimensions, with either free or cyclic boundary, has been the subject for a long running debate. The older papers have been based on ideas from e.g. field theory or renormalization. In this ... More

The scaling window of the 5D Ising model with free boundary conditionsJan 15 2016Jan 27 2016The five-dimensional Ising model with free boundary conditions has recently received a renewed interest in a debate concerning the finite-size scaling of the susceptibility near the critical temperature. We provide evidence in favour of the conventional ... More

Non-vanishing boundary effects and quasi-first order phase transitions in high dimensional Ising modelsOct 28 2010In order to gain a better understanding of the Ising model in higher dimensions we have made a comparative study of how the boundary, open versus cyclic, of a d-dimensional simple lattice, for d=1,...,5, affects the behaviour of the specific heat C and ... More

Reconstruction of the finite size canonical ensemble from incomplete micro-canonical dataDec 18 2006In this paper we discuss how partial knowledge of the density of states for a model can be used to give good approximations of the energy distributions in a given temperature range. From these distributions one can then obtain the statistical moments ... More

The discontinuity of the specific heat for the 5D Ising modelFeb 26 2015In this paper we investigate the behaviour of the specific heat around the critical point of the Ising model in dimension 5 to 7. We find a specific heat discontinuity, like that for the mean field Ising model, and provide estimates for the left and right ... More

Finite size scaling of the 5D Ising model with free boundary conditionsAug 23 2014There has been a long running debate on the finite size scaling for the Ising model with free boundary conditions above the upper critical dimension, where the standard picture gives a $L^2$ scaling for the susceptibility and an alternative theory has ... More

Critical behaviour of the Ising model on the 4-dimensional latticeFeb 14 2012In this paper we investigate the nature of the singularity of the Ising model of the 4-dimensional cubic lattice. It is rigorously known that the specific heat has critical exponent $\alpha=0$ but a non-rigorous field-theory argument predicts an unbounded ... More

On the Number of Matchings in Regular GraphsJan 15 2008For the set of graphs with a given degree sequence, consisting of any number of $2's$ and $1's$, and its subset of bipartite graphs, we characterize the optimal graphs who maximize and minimize the number of $m$-matchings. We find the expected value of ... More

Improved bounds for the shortness coefficient of cyclically 4-edge connected cubic graphs and snarksSep 16 2013Jan 07 2014We present a construction which shows that there is an infinite set of cyclically 4-edge connected cubic graphs on $n$ vertices with no cycle longer than $c_4 n$ for $c_4=\frac{12}{13}$, and at the same time prove that a certain natural family of cubic ... More

On 1-sum flows in undirected graphsMar 24 2015Let G=(V,E) be a simple undirected graph. For a given set L of the real line, a function omega from E to L is called an L-flow. Given a vector gamma whose coordinates are indexed by V, we say that omega is a gamma-L-flow if for each v in V, the sum of ... More

The straight line complexity of small factorials and primorialsJun 13 2013Dec 15 2014In this paper we determine the straight-line complexity of $n!$ for $n\leq 22$ and give bounds for the complexities up to $n=46$. In the same way we determine the straight-line complexity of the product of the first primes up to $p=31$ and gives bounds ... More

Problem collection from the IML programme: Graphs, Hypergraphs, and ComputingNov 01 2015This collection of problems and conjectures is based on a subset of the open problems from the seminar series and the problem sessions of the Institut Mitag-Leffler programme Graphs, Hypergraphs, and Computing. Each problem contributor has provided a ... More

From the Ising and Potts models to the general graph homomorphism polynomialJan 24 2014Nov 19 2015In this note we study some of the properties of the generating polynomial for homomorphisms from a graph to at complete weighted graph on $q$ vertices. We discuss how this polynomial relates to a long list of other well known graph polynomials and the ... More

Two questions of Erdős on hypergraphs above the Tur{á}n threshold}Nov 24 2011For ordinary graphs it is known that any graph $G$ with more edges than the Tur{\'a}n number of $K_s$ must contain several copies of $K_s$, and a copy of $K_{s+1}^-$, the complete graph on $s+1$ vertices with one missing edge. Erd\H{o}s asked if the same ... More

$\ell$-degree Turán densityOct 21 2012Oct 14 2014Let $H_n$ be a $k$-graph on $n$ vertices. For $0 \le \ell <k$ and an $\ell$-subset $T$ of $V(H_n)$, define the degree $\deg(T)$ of $T$ to be the number of $(k-\ell)$-subsets~$S$ such that $S \cup T$ is an edge in~$H_n$. Let the minimum $\ell$-degree of ... More

Minimum codegree threshold for $(K_4^3-e)$-factorsNov 24 2011Dec 30 2012Given hypergraphs H and F, an F-factor in H is a spanning subgraph consisting of vertex disjoint copies of F. Let K_4^3-e denote the 3-uniform hypergraph on 4 vertices with 3 edges. We show that for \gamma>0 there exists an integer n_0 such that every ... More

$F$-factors in hypergraphs via absorptionMay 17 2011Mar 24 2014Given integers $ n \ge k >l \ge 1 $ and a $k$-graph $F$ with $|V(F)|$ divisible by $n$, define $t_l^k(n,F)$ to be the smallest integer $d$ such that every $k$-graph $H$ of order $n$ with minimum $l$-degree $\delta_l(H) \ge d $ contains an $F$-factor. ... More

Perfect matchings in 3-partite 3-uniform hypergraphsMar 29 2011Oct 14 2014Let $H$ be a $3$-partite $3$-uniform hypergraph, i.e. a $3$-uniform hypergraph such that every edge intersects every partition class in exactly one vertex, with each partition class of size $n$. We determine a Dirac-type vertex degree threshold for perfect ... More

Partite Turán-densities for complete $r-$uniform hypergraphs on $r+1$ verticesMar 11 2019In this paper we investigate density conditions for finding a complete $r$-uniform hypergraph $K_{r+1}^{(r)}$ on $r+1$ vertices in an $(r+1)$-partite $r$-uniform hypergraph $G$. First we prove an optimal condition in terms of the densities of the $(r+1)$ ... More

Random Latin square graphsJun 01 2011In this paper we introduce new models of random graphs, arising from Latin squares which include random Cayley graphs as a special case. We investigate some properties of these graphs including their clique, independence and chromatic numbers, their expansion ... More

A multipartite version of the Hajnal-Szemerédi theorem for graphs and hypergraphsAug 21 2011Dec 30 2012A perfect $K_t$-matching in a graph $G$ is a spanning subgraph consisting of vertex disjoint copies of $K_t$. A classic theorem of Hajnal and Szemer\'edi states that if $G$ is a graph of order $n$ with minimum degree $\delta(G) \ge (t-1)n/t$ and $t| n$, ... More

The range of thresholds for diameter 2 in random Cayley graphsFeb 29 2012Given a group G, the model \mathcal{G}(G,p) denotes the probability space of all Cayley graphs of G where each element of the generating set is chosen independently at random with probability p. Given a family of groups (G_k) and a c \in \mathbb{R}_+ ... More

The thresholds for diameter 2 in random Cayley graphsAug 17 2011Given a group G, the model $\mathcal{G}(G,p)$ denotes the probability space of all Cayley graphs of G where each element of the generating set is chosen independently at random with probability p. In this article we show that for any $\epsilon > 0$ and ... More

Random subcube intersection graphs I: cliques and coveringSep 27 2013Jun 03 2015We study random subcube intersection graphs, that is, graphs obtained by selecting a random collection of subcubes of a fixed hypercube $Q_d$ to serve as the vertices of the graph, and setting an edge between a pair of subcubes if their intersection is ... More

Turán and Ramsey Properties of Subcube Intersection GraphsOct 19 2011The discrete cube $\{0,1\}^d$ is a fundamental combinatorial structure. A subcube of $\{0,1\}^d$ is a subset of $2^k$ of its points formed by fixing $k$ coordinates and allowing the remaining $d-k$ to vary freely. The subcube structure of the discrete ... More

Full subgraphsMay 12 2015Oct 21 2016Let $G=(V,E)$ be a graph of density $p$ on $n$ vertices. Following Erd\H{o}s, \L uczak and Spencer, an $m$-vertex subgraph $H$ of $G$ is called {\em full} if $H$ has minimum degree at least $p(m - 1)$. Let $f(G)$ denote the order of a largest full subgraph ... More

Speed and concentration of the covering time for structured coupon collectorsJan 18 2016Let $V$ be an $n$-set, and let $X$ be a random variable taking values in the powerset of $V$. Suppose we are given a sequence of random coupons $X_1, X_2, \ldots $, where the $X_i$ are independent random variables with distribution given by $X$. The covering ... More

Full subgraphsMay 12 2015Let $G$ be an $n$-vertex graph with edge-density $p$. Following Erd\H{o}s, \L uczak and Spencer, an $m$-vertex subgraph H of G is called full if it has minimum degree at least $p(m - 1)$. Let $f(G)$ denote the order of a largest full subgraph of $G$, ... More

Triangle-degrees in graphs and tetrahedron coverings in 3-graphsJan 28 2019We investigate a covering problem in $3$-uniform hypergraphs ($3$-graphs): given a $3$-graph $F$, what is $c_1(n,F)$, the least integer $d$ such that if $G$ is an $n$-vertex $3$-graph with minimum vertex degree $\delta_1(G)>d$ then every vertex of $G$ ... More

Generation and Properties of SnarksJun 28 2012Jun 28 2013For many of the unsolved problems concerning cycles and matchings in graphs it is known that it is sufficient to prove them for \emph{snarks}, the class of nontrivial 3-regular graphs which cannot be 3-edge coloured. In the first part of this paper we ... More

Latin Cubes with Forbidden EntriesSep 07 2018We consider the problem of constructing Latin cubes subject to the condition that some symbols may not appear in certain cells. We prove that there is a constant $\gamma > 0$ such that if $n=2^k$ and $A$ is $3$-dimensional $n\times n\times n$ array where ... More

Validations of the Asymptotic Matching ConjecturesFeb 28 2006Apr 11 2008In this paper we review the asymptotic matching conjectures for $r$-regular bipartite graphs, and their connections in estimating the monomer-dimer entropies in $d$-dimensional integer lattice and Bethe lattices. We prove new rigorous upper and lower ... More

Restricted completion of sparse partial Latin squaresAug 26 2016An $n \times n$ partial Latin square $P$ is called $\alpha$-dense if each row and column has at most $\alpha n$ non-empty cells and each symbol occurs at most $\alpha n$ times in $P$. An $n \times n$ array $A$ where each cell contains a subset of $\{1,\dots, ... More

Hearing the Shape of the Ising Model with a Programmable Superconducting-Flux AnnealerJul 03 2013Sep 17 2014Two objects can be distinguished if they have different measurable properties. Thus, distinguishability depends on the Physics of the objects. In considering graphs, we revisit the Ising model as a framework to define physically meaningful spectral invariants. ... More

More ties than we thoughtJan 31 2014May 06 2015We extend the existing enumeration of neck tie-knots to include tie-knots with a textured front, tied with the narrow end of a tie. These tie-knots have gained popularity in recent years, based on reconstructions of a costume detail from The Matrix Reloaded, ... More

On the Topology induced by Probabilistic Modular spacesMay 14 2013In this note, we investigate some topological properties of probabilistic modular spaces.

A Compton Thick AGN Powering the Hyperluminous Infrared Galaxy IRAS 00182--7112Aug 01 2007We present X-ray observations of the Hyperluminous Infrared Galaxy (HLIRG) IRAS 00182--7112 (F00183--7111) obtained using the XMM-Newton EPIC camera. A luminous hard X-ray source co-incident with the nucleus is revealed, along with weaker soft X-ray emission ... More

Triplet Pairing Superconductivity Induced by Short-Range Ferromagnetic Correlations in Sr$_2$RuO$_4$Aug 05 2005The microscopic origin of triplet superconductivity in Sr$_2$RuO$_4$ is discussed, paying attention to the role of Coulomb interaction, $U_{pp}$, at the O site. It is shown on the $d$-$p$ model that $U_{pp}$ induces a ferromagnetic exchange interaction ... More

Aspects of the inverse problem for the Toda chainJul 15 2013May 01 2015We generalize Babelon's approach to equations in dual variables so as to be able to treat new types of operators which we build out of the sub-constituents of the model's monodromy matrix. Further, we also apply Sklyanin's recent monodromy matrix identities ... More

Fine structure of the asymptotic expansion of cyclic integralsJan 20 2010The asymptotic expansion of $n$-dimensional cyclic integrals was expressed as a series of functionals acting on the symmetric function involved in the cyclic integral. In this article, we give an explicit formula for the action of these functionals on ... More

Asymptotic analysis and quantum integrable modelsAug 25 2015This habilitation thesis reviews the progress made by the author respectively to studying various asymptotic regimes of correlation functions in quantum integrable models.

Single vortex in a 2D optical latticesMar 03 2004Sep 22 2004The paper has been withdrawn due to technical reason.

The high-field magnetic white dwarf LP 790-29: not a fast rotatorDec 04 2001We have investigated the nature of the magnetic white dwarf LP 790-29 = LHS 2293 by polarimetric monitoring, searching for short-term variability. No periodicity was found and we can exclude rotation periods between 4 sec and 1.5 hour with a high confidence. ... More

Study of the Radiation Hardness of Vcsel and Pin ArraysJan 06 2009The silicon trackers of the ATLAS experiment at LHC (CERN) use optical links for data transmission. VCSEL arrays operating at 850 nm are used to transmit optical signals while PIN arrays are used to convert the optical signals into electrical signals. ... More

New Results on Tau LeptonNov 22 2003This is a review of new results on the Tau lepton. The lifetime has been measured with improved precision, allowing the test of lepton universality to 0.2% level. There are several new measurements of the branching ratios for the hadronic decays, including ... More

Scalar and vector form factors of the in-medium nucleonJul 12 2003Nov 07 2003Using the quark-meson coupling model, we calculate the form factors at sigma- and omega-nucleon strong-interaction vertices in nuclear matter. The Peierls-Yoccoz projection technique is used to take account of center of mass and recoil corrections. We ... More

Convergence of ray sequences of Pade approximants to 2F1(a,1;c;z), c>a>0Jan 05 2009The Pad\'e table of $\phantom{}_2F_1(a,1;c;z)$ is normal for $c>a>0$ (cf. \cite{3}). For $m \geq n-1$ and $c \notin {\zz}^{\phantom{}^-}$, the denominator polynomial $Q_{mn}(z)$ in the $[m/n]$ Pad\'e approximant $P_{mn}(z)/Q_{mn}(z)$ for $\phantom{}_2F_1(a,1;c;z)$ ... More

Zeros of linear combinations of Laguerre polynomials from different sequencesDec 03 2008We study interlacing properties of the zeros of two types of linear combinations of Laguerre polynomials with different parameters, namely $R_n=L_n^{\alpha}+aL_{n}^{\alpha'}$ and $S_n=L_n^{\alpha}+bL_{n-1}^{\alpha'}$. Proofs and numerical counterexamples ... More

Bounds for extreme zeros of some classical orthogonal polynomialsNov 04 2011We derive upper bounds for the smallest zero and lower bounds for the largest zero of Laguerre, Jacobi and Gegenbauer polynomials. Our approach uses mixed three term recurrence relations satisfied by polynomials corresponding to different parameter(s) ... More

Game of collusionsDec 12 2015A new model of collusions in an organization is proposed. Each actor $a_{i=1,\cdots,N}$ disposes one unique good $g_{j=1,\cdots,N}$. Each actor $a_i$ has also a list of other goods which he/she needs, in order from desired most to those desired less. ... More

Microscopic derivation of the Bekenstein-Hawking entropy formula for non-extremal black holesNov 18 1997Jan 10 1998We derive the Bekenstein-Hawking entropy formula for four and five dimensional non-supersymmetric black holes (which include the Schwarzchild ones) by counting microscopic states. This is achieved by first showing that these black holes are U-dual to ... More

Angular momentum and mass evolution of contact binariesMar 03 2008Sep 25 2008Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems. As the components of close detached binaries approach each other and contact ... More

Spectroscopy of diffuse light in dust clouds. Scattered light and the solar neighbourhood radiation fieldNov 30 2012The optical surface brightness of dark nebulae is mainly due to scattering of integrated starlight by classical dust grains. It contains information on the impinging interstellar radiation field, cloud structure, and grain scattering properties. We have ... More

Determination of the $Θ^+$ parity from $γn \to K^- K^+ n$Nov 09 2003Dec 26 2003It is demonstrated that measurements of photon asymmetry in the $\gamma n \to K^- K^+ n$ reaction, can most likely determine the parity of the newly discovered $\Theta^+$ pentaquark. We predict that if the parity of $\Theta^+$ is positive, the photon ... More

Electronic Structures of MgB{$_2$} under Uniaxial and Hydrostatic CompressionMay 11 2001Electronic and lattice properties of MgB{$_2$} under uniaxial and hydrostatic compression are calculated. Lattice properties are optimized automatically by using the first-principles molecular dynamics (FPMD) method. Features of the electronic band structures ... More

On the correlation between the X-ray and gamma-ray emission in TeV blazarsDec 09 2009The observations of TeV blazars published recently show an unexpected quadratic or even cubic correlation between the X-ray and gamma-ray emission. A standard model of the synchrotron self-Compton emission of a compact source inside a jet is not able ... More

Slave boson model for two-dimensional trapped Bose-Einstein condensateApr 11 2005A system of N bosons in a two-dimensional harmonic trap is considered. The system is treated in term of the slave boson representation for hard-core bosons which is valid in the arbitrary density regimes. I discuss the consequences of higher order interactions ... More

Yukawa bosons in two-dimensional Harmonic confinementMar 24 2005Sep 06 2007The ground state property of Yukawa Bose fluid confined in a radial harmonic trap is studied. The calculation was carried out using the density functional theory formalism within the Kohn-Sham scheme. The excess-correlation energy for this inhomogeneous ... More

Radiation-Hard Opto-Link for the Atlas Pixel DetectorOct 20 2004Oct 21 2004The on-detector optical link of the ATLAS pixel detector contains radiation-hard receiver chips to decode bi-phase marked signals received on PIN arrays and data transmitter chips to drive VCSEL arrays. The components are mounted on hybrid boards (opto-boards). ... More

Review of Rare and Forbidden $τ$ DecaysJul 02 1997This is a review of rare and forbidden decays of the $\tau$ lepton. For the rare decays, this includes new results on the chiral anomaly decay $\taupietapio$, new upper limits on the second-class-current decay $\taupieta$, and the observations of the ... More

Radiation-hard ASICs for optical data transmission in the ATLAS pixel detectorSep 11 2004We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a ... More

Born-Infeld strings between D-branesAug 24 1999We examine the solutions of world-volume action for a D3-brane being put near other D3-brane which is replaced by the background configuration of bulk space. It is shown that the BPS solutions are not affected by the D3-brane background, and they are ... More

Collimation of the e^+e^- annihilation eventMay 06 1997The collimation $C$ of a hadronic event in the e^+e^- annihilation is defined as the average of $\cos\theta$, $C=<\cos\theta>$, where $\theta$ is the angle of each hadron measured from the thrust axis, and the average is over all the hadrons produced ... More

Dynamical fermions in lattice quantum chromodynamicsDec 31 2007The thesis will present results in Quantum Chromo Dynamics (QCD) with dynamical lattice fermions. The topological susceptibilty in QCD is determined, the calculations are carried out with dynamical overlap fermions. The most important properties of the ... More

Effects of neutrino oscillation on supernova neutrino: inverted mass hierarchyMay 08 2002May 06 2003We study the effects of neutrino oscillation on supernova neutrino in the case of the inverted mass hierarchy ($m_{3} \ll m_{1} < m_{2}$) as well as the normal mass hierarchy ($m_{1} < m_{2} \ll m_{3}$). Numerical analysis using a realistic supernova ... More

Earth effects on supernova neutrinos and their implications for neutrino parametersOct 08 2001Mar 23 2002We perform a detailed study of the Earth matter effects on supernova neutrinos with neutrino oscillation parameter LMA and small $\theta_{13}$. The Earth effects show significant dependences on the neutrino path length inside the Earth and the value of ... More

Paradox of integration -- Dynamics of two-dimensional statusMar 11 2019According to Peter M. Blau [Exchange and Power in Social Life, Wiley and Sons, p. 43], the process of integration of a newly formed group has a paradoxical aspect: most attractive individuals are rejected because they raise fear of rejection. Often, their ... More

Radiation-Hard Asics for Optical Data Transmission in the Atlas Pixel DetectorAug 10 2004We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a ... More

Radiation-hard ASICs for optical data transmission in the ATLAS pixel detectorMar 13 2003We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a ... More

Incorporation of the statistical uncertainty in the background estimate into the upper limit on the signalJul 25 1997We present a procedure for calculating an upper limit on the number of signal events which incorporates the Poisson uncertainty in the background, estimated from control regions of one or two dimensions. For small number of signal events, the upper limit ... More

Optical Link of the Atlas Pixel DetectorDec 06 2007The on-detector optical link of the ATLAS pixel detector contains radiation-hard receiver chips to decode bi-phase marked signals received on PIN arrays and data transmitter chips to drive VCSEL arrays. The components are mounted on hybrid boards (opto-boards). ... More

Search for Neutrinoless Tau Decays Involving the K0 MesonNov 11 2002We have searched for lepton flavor violating decays of the tau lepton with one or two KS0 mesons in the final state. The data used in the search were collected with the CLEO II and II.V detectors at the Cornell Electron Storage Ring (CESR) and correspond ... More

High-resolution spectroscopy of the intermediate polar EX Hydrae. I. Kinematic study and Roche tomographyFeb 18 2008EX Hya is one of the few double-lined eclipsing cataclysmic variables that allow an accurate measurement of the binary masses. We analyze orbital phase-resolved UVES/ VLT high resolution spectroscopic observations of EX Hya with the aims of deriving the ... More

Near-IR Properties of Quasar Host GalaxiesJan 23 1997We have obtained deep, near-IR images of nearly 100 host galaxies of nearby quasars and Seyferts. We find the near-IR light to be a good tracer of luminous mass in these galaxies. For the most luminous quasars there is a correlation between the maximum ... More

Evolution of Low Mass Contact BinariesJul 17 2012We present a study on low-mass contact binaries (LMCB) with orbital periods shorter than 0.3 days and total mass lower than about 1.4 solar mass. We show that such systems have a long pre-contact phase, which lasts for 8-9 Gyrs, while the contact phase ... More

Deformation of Fermi Surface Due to Antiferromagnetic CorrelationDec 16 1999It is investigated, on the basis of the fluctuation exchange approximation, how the shape of the Fermi surface is modified in two-dimensional $t-t'-U$ Hubbard model at half filling as strength of the onsite Coulomb interaction $U$ is increased. The antiferromagnetic ... More

On condensation properties of Bethe roots associated with the XXZ chainAug 24 2015I prove that the Bethe roots describing either the ground state or a certain class of "particle-hole" excited states of the XXZ spin-$1/2$ chain in any sector with magnetisation $\mathfrak{m} \in [0;1/2]$ exist and form, in the infinite volume limit, ... More

Large-distance and long-time asymptotic behavior of the reduced density matrix in the non-linear Schrödinger modelJan 08 2011May 05 2011Starting from the form factor expansion in finite volume, we derive the multidimensional generalization of the so-called Natte series for the zero-temperature, time and distance dependent reduced density matrix in the non-linear Schr\"{o}dinger model. ... More

On the emptiness formation probability of the open XXZ spin-$\tf{1}{2}$ chainAug 02 2007This paper is devoted to the study of the emptiness formation probability $\tau\pa{m}$ of the open XXZ chain. We derive a closed form for $\tau\pa{m}$ at $\Delta=\tf{1}{2}$ when the boundary field vanishes. Moreover we obtain its leading asymptotics for ... More

Multiplicity with a Thrust CutDec 28 1993We evaluate the multiplicity of hadrons in the $e^+e^-$-annihilation at a given thrust $T$ in the modified leading-log approximation, including $O(\sqrt{\alpha_s})$ corrections. The calculation is done at a large value of $\tau =1-T$ by the use of the ... More

Semiclassical expansion of the Slater sum for position dependent mass distributions in d dimensionsOct 04 2012Apr 26 2013We consider hamiltonian systems with spatially varying effective mass and slowly varying local potential in d dimensions. The Slater sum is defined as the diagonal element of the Bloch propagator. We derive a gradient expansion of the Slater sum up to ... More

Bipolar Supernova Explosions: Nucleosynthesis & Implication on Abundances in Extremely Metal-Poor StarsApr 09 2003Aug 08 2003Hydrodynamics and explosive nucleosynthesis in bipolar supernova explosions are examined to account for some peculiar properties of hypernovae as well as peculiar abundance patterns of metal-poor stars. The explosion is supposed to be driven by bipolar ... More

Zeros of the hypergeometric polynomial F(-n,b;c;z)Dec 03 2008Our interest lies in describing the zero behaviour of Gauss hypergeometric polynomials $F(-n,b; c; z)$ where $b$ and $c$ are arbitrary parameters. In general, this problem has not been solved and even when $b$ and $c$ are both real, the only cases that ... More

Theory of Ultrasonic Dispersion in Local Phonon Systems Coupled with Conduction ElectronsJul 25 2007The physical origin of frequency dependence in elastic constants, which are often found in an ultrasound propagation in filled skutterudites and clathrate compounds, is investigated theoretically. This dependence arises from a coupling between the acoustic ... More

On Form Factors of the conjugated field in the non-linear Schröodinger modelMay 05 2011Izergin-Korepin's lattice discretization of the non-linear Schr\"odinger model along with Oota's inverse problem provides one with determinant representations for the form factors of the lattice discretized conjugated field operator. We prove that these ... More

High Kondo temperature (TK ~ 80 K) in self-assembled InAs quantum dots laterally coupled to nanogap electrodesAug 19 2008We have fabricated single electron tunneling structures by forming nanogap metallic electrodes directly upon single self-assembled InAs quantum dots (QDs). The fabricated samples exhibited clear Coulomb blockade effects. Furthermore, a clear Kondo effect ... More

Probing internucleus potential with large-angle quasi-elastic scatteringMay 08 2006Recent measurements for fusion cross section at energies around the Coulomb barrier have systematically indicated a significant deviation of fusion cross sections from a prediction of double-folding model. It has been argued that the deviation can be ... More

Microscopic Theory of Trapped Two-Dimensional Bose GasMar 29 2005This report is based on my incomplete Phd thesis. The final part of the work on the 2D Yukawa bosons/vortices in a confined geometry is not complete and subject to futher development.

New Results on ATLAS Pixel Opto-LinkJan 30 2002We present new results on the optical link for the pixel detector of the ATLAS experiment. An optical package of novel design has been developed for the opto-link. The design is based on a simple connector-type concept and is made of radiation-hard material. ... More

A Novel Optical Package for ATLAS Pixel DetectorMar 10 2001An optical package of novel design has been developed for the ATLAS pixel detector. The package contains two VCSELs and one PIN diode to transmit and receive optical signals. The design is based on a simple connector-type concept and is made of radiation-hard ... More

Radiation-Hard Optical Link for SLHCDec 29 2008We study the feasibility of fabricating an optical link for the SLHC ATLAS silicon tracker based on the current pixel optical link architecture. The electrical signals between the current pixel modules and the optical modules are transmitted via micro-twisted ... More

An MT-Style Optical Package for Optical Data TransmissionMar 03 2003An optical package for mounting VCSEL and PIN diodes for transmitting and receiving optical signals has been developed. The diodes couple to the fibers in a commercial MT connector. The package is quite compact with its physical size significantly smaller ... More

Thermodynamic Phase Diagram of the Quantum Hall Skyrmion SystemAug 22 1999We numerically study the interacting quantum Hall skyrmion system based on the Chern-Simons action. By noticing that the action is invariant under global spin rotations in the spin space with respect to the magnetic field direction, we obtain the low-energy ... More

A Probabilistic Proof of the Multinomial TheoremAug 04 2016In this note, we give an alternate proof of the multinomial theorem using a probabilistic approach. Although the multinomial theorem is basically a combinatorial result, our proof may be simpler for a student familiar with only basic probability concepts. ... More

Approximate symmetries of geodesic equations on 2-spheresMay 09 2010Approximate symmetries of geodesic equations on 2-spheres are studied. These are the symmetries of the perturbed geodesic equations which represent approximate path of a particle rather than exact path. After giving the exact symmetries of the geodesic ... More

Electron-Electron Interaction in Linear Arrays of Small Tunnel JunctionsOct 03 1995We have calculated the spatial distribution of the electrostatic potential created by an unbalanced charge $q$ in one of the conducting electrodes of a long, uniform, linear array of small tunnel junctions. The distribution describes, in particular, the ... More

Solution Independent Analysis of Black Hole Entropy in Brick Wall ModelMay 26 2005Jun 06 2007Using the brick wall regularization of 't Hooft, the entropy of non-extreme and extreme black holes is investigated in a general static, spherically symmetric spacetime. We classify the singularity in the entropy by introducing a {\it new} index $\delta ... More

Ultracold bosons in a synthetic periodic magnetic field: Mott phases and re-entrant superfluid-insulator transitionsMay 25 2010We study Mott phases and superfluid-insulator (SI) transitions of ultracold bosonic atoms in a two-dimensional square optical lattice at commensurate filling and in the presence of a synthetic periodic vector potential characterized by a strength $p$ ... More

Lexicographic Multi-objective Geometric Programming ProblemsDec 09 2009A Geometric programming (GP) is a type of mathematical problem characterized by objective and constraint functions that have a special form. Many methods have been developed to solve large scale engineering design GP problems. In this paper GP technique ... More