February 2000 arXiv papers — page 3

Mikhail Chkhenkeli, Thomas Garrity

This is primarily an expository note showing that earlier work of Lai on CR geometry provides a clean interpretation, in terms of a Gauss map, for an adjunction formula for embedded surfaces in an almost complex four manifold. We will see that if F is a surface with genus g in an almost complex four-manifold M, then 2 - 2 g + F \cdot F - i^{*} c_{1}(M) - 2 F

Jozef H. Przytycki, Maxim V. Sokolov

We show that a closed orientable 3-manifold M admits an action of Z_p with fixed point set S^1 iff M can be obtained as the result of surgery on a p-periodic framed link L and Z_p acts freely on the components of L. We prove a similar theorem for free Z_p-actions. As an interesting application, we prove the following, rather unexpected result: for any M as a

Dirk Calow, Rainer Matthes

If P, B, H are the algebras of the total space, the base space, and the structure group of a locally trivial principal fibre bundle (QPFB), left (right) gauge transformations are defined as automorphisms of the left (right) B-module P which are adapted to the coaction of the Hopf algebra H and to the covering related to the local trivializations. Covariant d

Dirk Calow, Rainer Matthes

We define locally trivial quantum vector bundles (QVB) and QVB associated to locally trivial quantum principal fibre bundles. There exists a differential structure on the associated vector bundle coming from the differential structure on the principal bundle, which allows to define connections on the associated vector bundle associated to connections on the

Dirk Calow, Rainer Matthes

Following the approach of Budzyński and Kondracki, we define covariant differential algebras and connections on locally trivial quantum principal fibre bundles. We also consider covariant derivatives, connection forms and curvatures and explore the relations between these notions. As an example, a U(1) quantum principal bundle over a glued quantum sphere and

Ashok Kumar Gupta, Ashok Kumar Mittal

The notion of 'bifurcating continued fractions' is introduced. Two coupled sequences of non-negative integers are obtained from an ordered pair of positive real numbers in a manner that generalizes the notion of continued fractions. These sequences enable simple representations of roots of cubic equations. In particular, remarkably simple and elegant

J. Gasser, M. E. Sainio

We consider sigma-terms in $ππ$, $πN$ and $K N$ scattering. While the state of the art in $ππ$ is in principle crystal clear, the kaon-nucleon case is largely unexplored. The pion-nucleon system is in-between. We propose a list of topics to be investigated in kaon-nucleon scattering, in order to make optimal use of the precision data expected from DEAR.

Paolo Lipari

The zenith angle distributions of atmospheric neutrinos are determined by the possible presence of neutrino oscillations and the combination of three most important contributions: (1) geomagnetic effects on the primary cosmic rays, that suppress the primary flux in the Earth's magnetic equatorial region, (2) the zenith angle dependence of the neutrino yi

Dumitru Baleanu

In this paper the symmetries of the dual manifold were investigated. We found the conditions when the manifold and its dual admit the same Killing vectors and Killing-Yano tensors. In the case of an Einstein's metric $g_{μν}$ the corresponding equations for its dual were found. The examples of Kerr-Newman geometry and the separable coordinates in 1+1 dim

V. Kromer

A new word usage measure is proposed. It is based on psychophysical relations and allows to reveal words by its degree of "importance" for making basic dictionaries of sublanguages.

Benny Davidovich, M. J. Feigenbaum, H. G. E. Hentschel, Itamar Procaccia

Many models of fractal growth patterns (like Diffusion Limited Aggregation and Dielectric Breakdown Models) combine complex geometry with randomness; this double difficulty is a stumbling block to their elucidation. In this paper we introduce a wide class of fractal growth models with highly complex geometry but without any randomness in their growth rules.

S. Rouziere, S. Margadonna, K. Prassides, A. N. Fitch

We report the results of a high-resolution synchrotron X-ray powder diffraction study of polymerised CsC$_{60}$ in the temperature range 4 to 40 K. Its crystal structure is monoclinic (space group I2/m), isostructural with RbC$_{60}$. Below 14 K, a spontaneous thermal contraction is observed along both the polymer chain axis, $a$ and the interchain separatio

Etsuro Date, Shi-shyr Roan

We study the Lie algebra structure of the Onsager algebra from the ideal theoretic point of view. A structure theorem of ideals in the Onsager algebra is obtained with the connection to the finite-dimensional representations. We also discuss the solvable algebra aspect of the Onsager algebra through the formal Lie algebra theory.

Kurt W. Weiler, Nino Panagia, Richard A. Sramek, Schuyler D. Van Dyk

Study of radio supernovae (RSNe) over the past 20 years includes two dozen detected objects and more than 100 upper limits. From this work we are able to identify classes of radio properties, demonstrate conformance to and deviations from existing models, estimate the density and structure of the circumstellar material and, by inference, the evolution of the

X. Hernandez, D. Valls-Gabaud, G. Gilmore

The evolution of the star formation rate in the Galaxy is one of the key ingredients quantifying the formation and determining the chemical and luminosity evolution of galaxies. Many complementary methods exist to infer the star formation history of the components of the Galaxy, from indirect methods for analysis of low-precision data, to new exact analytic

J. A. Rubino-Martin, F. Atrio-Barandela, C. Hernandez-Monteagudo

We limit the contribution of the hot intracluster gas, by means of the Sunyaev-Zel'dovich effect, to the temperature anisotropies measured by the Tenerife experiment. The data is cross-correlated with maps generated from the ACO cluster catalogue, the ROSAT PSPC catalogue of clusters of galaxies, a catalogue of superclusters and the HEAO 1 A-1 map of X-r

Sayipjamal Dulat, Katrin Wendland

We study the moduli space C^2 of unitary two-dimensional conformal field theories with central charge c=2. We construct all the 28 nonexceptional nonisolated irreducible components of C^2 that may be obtained by an orbifold procedure from toroidal theories. The parameter spaces and partition functions are calculated explicitly, and all multicritical points a

Andrei Shelankov

The paraxial (parabolic) theory of a near forward scattering of a quantum charged particle by a static magnetic field is presented. From the paraxial solution to the Aharonov-Bohm scattering problem the transverse transfered momentum (the Lorentz force) is found. Multiple magnetic scattering is considered for two models: (i) Gaussian $δ$ -correlated random m

Miloslav Znojil

We show that the potential wells with a central spike V(x) = x^{10} + a x^8 + b x^6+ c x^4 + d x^2 + f/x^2 possess arbitrary finite multiplets of elementary exact bound states. The strong asymptotic growth of V(x) implies an ambiguity in the PT-symmetric quantization via complex boundary conditions but the three eligible recipes coincide at our exceptional s

Valerio Faraoni

The nonminimal coupling (NMC) of the scalar field to the Ricci curvature is unavoidable in many cosmological scenarios. Inflation and quintessence models based on nonminimally coupled scalar fields are studied, with particular attention to the balance between the scalar potential and the NMC term in the action. NMC makes acceleration of the universe harder t

M. Ambrosio

High energy gamma ray astronomy is now a well established field and several sources have been discovered in the region from a few GeV up to several TeV. If sources involving hadronic processes exist, the production of photons would be accompanied by neutrinos too. Other possible neutrino sources could be related to the annihilation of WIMPs at the center of

Ryuichiro Kitano

Lepton flavor violation in the Randall-Sundrum model with bulk neutrinos is considered. Grossman and Neubert recently proposed that the existence of tiny neutrino masses and large mixing could be explained by the presence of the bulk neutrinos in the Randall-Sundrum background. Since the zero mode wave functions of the bulk neutrinos are localized on Planck

Oren Bergman, Kentaro Hori, Piljin Yi

A non-perturbative confinement mechanism has been proposed to explain the fate of the unbroken gauge group on the world-volume of annihilating D-brane-anti-D-brane pairs. In this paper, we examine this phenomenon closely from several different perspectives. Existence of the confinement mechanism is most easily seen by noticing that the fundamental string eme

Frank J. Masci, J. J. Condon, T. A. Barlow, C. J. Lonsdale

The Very Large Array (VLA) has been used in C-configuration to map an area \~0.3 square degrees at 1.4 GHz with 5sigma sensitivities of 0.305, 0.325, 0.380 and 0.450 mJy/beam over four equal subareas. Radio properties are presented for 62 detected sources. Deep optical imaging to Gunn r~25 mag using the Hale 5-m telescope covering ~0.21 square degrees is rep

V. A. Reshetov

The Jaynes-Cummings model describing the interaction of a single linearly- polarized mode of the quantized electromagnetic field with an isolated two- level atom is generalized to the case of atomic levels degenerate in the projections of the angular momenta on the quantization axis, which is a usual case in the experiments. This generalization, like the ori

T. Falter, S. Leupold, U. Mosel

The early onset of nuclear shadowing in photoabsorption at low photon energies has recently been interpreted as a possible signature of a decrease of the rho meson mass in nuclei. We show that one can understand this early onset within simple Glauber theory if one takes the negative real part of the rho N scattering amplitudes into account, corresponding to

Naoki Tajima

The two-basis method to solve the HFB for deformed nuclei in coordinate space is examined concerning the precision of the density tail. Small cutoff energies are shown to give rise to ripples in the tail, whose wave length corresponds to the cutoff momentum. More precise solutions require higher cutoff energies, which result in HFB matrices of larger dimensi

Naoki Tajima

The Hartree-Fock-Bogoliubov equation for the ground states of even-even atomic nuclei is solved using the canonical representation in the coordinate space for zero range interactions like the Skyrme force. The gradient method is improved for faster convergence to the solutions under constraint of orthogonality between canonical orbitals. Necessity of the cut

John F. McGowan, Ph. D

Complex systems with tightly coadapted parts frequently appear in living systems and are difficult to account for through Darwinian evolution, that is random variation and natural selection, if the constituent parts are independently coded in the genetic code. If the parts are independently coded, multiple simultaneous mutations appear necessary to create or

Natsuki Nagao, Haruhiko Nishimura, Nobuyuki Matsui

We present a perception model of ambiguous patterns based on the chaotic neural network and investigate the characteristics through computer simulations. The results induced by the chaotic activity are similar to those of psychophysical experiments and it is difficult for the stochastic activity to reproduce them in the same simple framework. Our demonstrati

V. V. Borzov

For any orthogonal polynomials system on real line we construct an appropriate oscillator algebra such that the polynomials make up the eigenfunctions system of the oscillator hamiltonian. The general scheme is divided into two types: a symmetric scheme and a non-symmetric scheme. The general approach is illustrated by the examples of the classical orthogona

F. A. Belgun

In the complex-Riemannian framework we show that a conformal manifold containing a compact, simply-connected, null-geodesic is conformally flat. In dimension 3 we use the LeBrun correspondence, that views a conformal 3-manifold as the conformal infinity of a selfdual four-manifolds. We also find a relation between the conformal invariants of the conformal in

F. A. Belgun

We study normal CR compact manifolds in dimension 3. For a choice of a CR Reeb vector field, we associate a Sasakian metric on them, and we classify those metrics. As a consequence, the underlying manifolds are topologically finite quotiens of the 3-sphere or of a circle bundle over a Riemann surface of positive genus. In the latter case, we prove that their

D. Fioravanti, G. Mussardo, P. Simon

We consider the universality class of the two-dimensional Tricritical Ising Model. The scaling form of the free-energy naturally leads to the definition of universal ratios of critical amplitudes which may have experimental relevance. We compute these universal ratios by a combined use of results coming from Perturbed Conformal Field Theory, Integrable Quant

B. B. Deo

A string in four dimensions is constructed by supplementing it with forty four Majorana fermions. The central charge is 26. The fermions are grouped in such a way that the resulting action is supersymmetric. The energy momentum and current generators satisfy the super-Virasoro algebra. The tachyonic ground state decouples from the physical states. GSO projec

R. N. Faustov, A. P. Martynenko

Self-energy corrections of order O(alpha^2) to the parapositronium and orthopositronium decay rates are calculated. Numerical values of the corresponding coefficients are B_p=-3.74, B_o=2.02.

P. Ko

I summarize our recent works on the effects of flavor conserving CP violating phases in SUSY models on $B$ and $K$ phenomenology.

Lianshou liu, Gang Chen, Jinghua Fu

It is shown using Lund Monte Carlo that, unlike the average properties of the hadronic system inside jets, the anisotropy of dynamical fluctuations in these systems changes abruptly with the variation of the cut parameter $y_cut$. A transition point exists, where the dynamical fluctuations in the hadronic system inside jet behave like those in soft hadronic

Murat Özer

We first review the cosmological constant problem, and then mention a conjecture of Feynman according to which the general relativistic theory of gravity should be reformulated in such a way that energy does not couple to gravity. We point out that our recent unification of gravitation and electromagnetism through a symmetric tensor has the property that the

P. J. E. Peebles

Dark matter modeled as a classical scalar field that interacts only with gravity and with itself by a potential that is close to quartic at large field values and approaches a quadratic form when the field is small would be gravitationally produced by inflation and at the present epoch could act like an ideal fluid with pressure that is a function only of th

Bahram Mobasher, Phil. A. James

Near-IR spectra for a sample of 31 elliptical galaxies in the Coma cluster are obtained. The galaxies are selected to be ellipticals (no lenticulars), with a large spatial distribution, covering both the core and outskirt of the cluster (ie. corresponding to regions with large density contrasts). Spectroscopic CO (2.3 micron) absorption indices, measuring co

P. A. James, B. Mobasher

We present near-infrared K-band spectroscopy of 21 elliptical or cD Brightest Cluster Galaxies (BCGs), for which we have measured the strength of the 2.293 micron CO stellar absorption feature. We find that the strength of this feature is remarkably uniform among these galaxies, with a smaller scatter in equivalent width than for the normal elliptical popula

N. A. Levenson, James R. Graham, Ian S. McLean, E. E. Becklin

We present high-resolution spectroscopy and images of a photodissociation region (PDR) in M16 obtained during commissioning of NIRSPEC on the Keck II telescope. PDRs play a significant role in regulating star formation, and M16 offers the opportunity to examine the physical processes of a PDR in detail. We simultaneously observe both the molecular and ionize

David Charbonneau, Robert W. Noyes

Close-in extrasolar giant planets may be directly detectable by their reflected light, due to the proximity of the planet to the illuminating star. The spectrum of the system will contain a reflected light component that varies in amplitude and Doppler shift as the planet orbits the star. Intensive searches for this effect have been carried out for only one

Branislav K. Nikolic, Philip B. Allen

We study the transport properties of a three dimensional atomic-scale contact in the ballistic regime. The results for the conductance and related transmission eigenvalues show how the properties of the ideal semi-infinite leads (i.e. measuring device) as well as the coupling between the leads and the conductor influence the transport in a two-probe geometry

Christophe Josserand, Alexei Tkachenko, Daniel M. Mueth, Heinrich M. Jaeger

We present a combined experimental and theoretical study of memory effects in vibration-induced compaction of granular materials. In particular, the response of the system to an abrupt change in shaking intensity is measured. At short times after the perturbation a granular analog of aging in glasses is observed. Using a simple two-state model, we are able t

Gösta Gustafson, Gabriela Miu

When studying the production of minijets and transverse energy flow in high energy hadron-hadron or nucleus-nucleus collisions, two essential points have to be taken into account. First, one has to account for the virtuality of the colliding partons and secondly, it is important to avoid double counting, when many links in a parton chain can be interpreted a

P. D. Vu, Xiao Liu, R. O. Pohl

We have measured the heat conduction between 0.05 K and 1.0 K of high purity silicon wafers carrying on their polished faces a variety of thin dielectric films and polycrystalline thin metallic films. Using a Monte Carlo simulation to analyze the conduction measurements, we have determined the phonon mean free path within the films, and found all of them to

F. Sannino

We note that the QCD phases at large finite density respect 't Hooft anomaly matching conditions. Specifically the spectrum of the light excitations possesses the correct quantum numbers required to obey global anomaly constraints. We argue that 't Hooft constraints can be used at finite density along with non perturbative methods to help selecting t

John Ellis, G. K. Leontaris, J. Rizos

A generic feature of string-derived models is the appearance of an anomalous Abelian U(1)_A symmetry which, among other properties, constrains the Yukawa couplings and distinguishes the three families from each other. In this paper, we discuss in a model-independent way the general constraints imposed by such a U(1)_A symmetry on fermion masses, R-violating

Luigi Amico

Algebraic contraction is proposed to realize mappings between models Hamiltonians. This transformation contracts the algebra of the degrees of freedom underlying the Hamiltonian. The rigorous mapping between the anisotropic $XXZ$ Heisenberg model, the Quantum Phase Model, and the Bose Hubbard Model is established as the contractions of the algebra $u(2)$ und

David P. DiVincenzo, IBM

After a brief introduction to the principles and promise of quantum information processing, the requirements for the physical implementation of quantum computation are discussed. These five requirements, plus two relating to the communication of quantum information, are extensively explored and related to the many schemes in atomic physics, quantum optics, n

James M. Cline, Kimmo Kainulainen

One of the most experimentally testable explanations for the origin of the baryon asymmetry of the universe is that it was created during the electroweak phase transition, in the minimal supersymmetric standard model. Previous efforts have focused on the current for the difference of the two Higgsino fields, $H_1-H_2$, as the source of biasing sphalerons to

M. C. B. Abdalla, A. L. Gadelha, I. V. Vancea

The duality between the Cartesian coordinates on the Minkowski space-time and the Dirac field is investigated. Two distinct possibilities to define this duality are shown to exist. In both cases, the equations satisfied by prepotentials are of second order.

Mikko J. Alava, Kent Bækgaard Lauritsen

The dynamics of sandpile models are mapped to discrete interface equations. We study in detail the Bak-Tang-Wiesenfeld model, a stochastic model with random thresholds, and the Manna model. These are, respectively, discretizations of the quenched Edwards-Wilkinson equation with columnar, point-like and correlated noise, with the constraint that the interface

V. A. Korotkov, W. -D. Nowak, K. A. Oganessyan

A method is discussed to determine the hitherto unknown u-quark transversity distribution from a planned HERMES measurement of a single-spin asymmetry in semi-inclusive pion electroproduction off a transversely polarized target. Assuming u-quark dominance, the measurement yields the shapes of the transversity distribution and of the ratio of a polarized and

Helen A. Bridgman, David Wands

We investigate four-dimensional cosmological vacuum solutions derived from an effective action invariant under global SL(n,R) transformations. We find the general solutions for linear axion field perturbations about homogeneous dilaton-moduli-vacuum solutions for an SL(4,R)-invariant action and find the spectrum of super-horizon perturbations resulting from

F. Becattini, J. Cleymans, A. Keranen, E Suhonen

A systematic study is performed of fully integrated particle multiplicities in central Au-Au and Pb-Pb collisions at beam momenta of 1.7A GeV, 11.6A GeV (Au-Au) and 158$A$ GeV (Pb-Pb) by using a statistical-thermal model. The close similarity of the colliding systems makes it possible to study heavy ion collisions under definite initial conditions over a ran

K. L. Janssens, F. M. Peeters, V. A. Schweigert

The groundstate energy and binding energy of an exciton, confined in a^M quantum disk, are calculated as a function of an external magnetic field. The confinement potential is a hard wall of finite height. The diamagnetic shift is investigated for magnetic fields up to 40$T$. Our results are applied to $In_{y}Al_{1-y}As/Al_{x}Ga_{1-x}As$ self-assembled quant

Amina Helmi, Simon D. M. White

We present two simple dynamical models for Sagittarius based on N-body simulations of the progressive disruption of a satellite galaxy orbiting for 12.5 Gyr within a realistic Galactic potential. In both models the satellite initially has observable properties similar to those of current outlying dwarfs; in one case it is purely stellar while in the other it

A. G. Grozin

An algorithm for calculation of three-loop propagator diagrams in HQET, based on integration-by-parts recurrence relations, is constructed and implemented as a REDUCE package Grinder, and in Axiom.

M. Hirsch, J. C. Romao, J. W. F. Valle

Neutrinoless double beta ($\znbb$) decay is considered within bilinear R-parity breaking supersymmetry, including the full one-loop corrections to the neutrino-neutralino mass matrix. Expected rates for $\znbb$ decay in this model are discussed in light of recent atmospheric and solar neutrino data. We conclude that (a) tree-level calculations for $\znbb$ de

V. D. Ivashchuk, V. N. Melnikov

Black hole generalized p-brane solutions for a wide class of intersection rules are obtained. The solutions are defined on a manifold that contains a product of n - 1 Ricci-flat internal spaces. They are defined up to a set of functions H_s obeying non-linear differential equations equivalent to Toda-type equations with certain boundary conditions imposed. A

E. Churazov, M. Haehnelt, O. Kotov, R. Sunyaev

For the low density filamentary and sheet-like structures in the warm ($\sim 10^4$ to $\sim 10^6$ K) IGM predicted by numerical simulations the resonant line scattering of X-ray background (XRB) photons by He and H-like ions of heavy elements can exceed the ``local'' thermal emission by a factor of a few or more. Due to the conservative nature of sca

M. B. Plenio, S. Virmani, P. Papadopoulos

We introduce the theory of operator monotone functions and employ it to derive a new inequality relating the quantum relative entropy and the quantum conditional entropy. We present applications of this new inequality and in particular we prove a new lower bound on the relative entropy of entanglement and other properties of entanglement measures.

Hans-Andreas Engel, Daniel Loss

We study Berry phase effects on conductance properties of diffusive mesoscopic conductors, which are caused by an electron spin moving through an orientationally inhomogeneous magnetic field. Extending previous work, we start with an exact, i.e. not assuming adiabaticity, calculation of the universal conductance fluctuations in a diffusive ring within the we

Yvette Kosmann-Schwarzbach, Juan Monterde

We define the divergence operators on a graded algebra, and we show that, given an odd Poisson bracket on the algebra, the operator that maps an element to the divergence of the hamiltonian derivation that it defines is a generator of the bracket. This is the "odd laplacian", $Δ$, of Batalin-Vilkovisky quantization. We then study the generators of od

V. D. Ivashchuk, V. N. Melnikov

Black hole generalized p-brane solutions for a wide class of intersection rules are presented. The solutions are defined on a manifold that contains a product of n - 1 Ricci-flat internal spaces. They are defined up to moduli functions H_s = H_s(R) obeying a non-linear differential equations (equivalent to Toda-type equations) with certain boundary condition

Hiroki Saito, Masahito Ueda

The collapsing dynamics of a trapped Bose-Einstein condensate (BEC) with attractive interaction are revealed to exhibit two previously unknown phenomena. During the collapse, BEC undergoes a series of rapid implosions that occur {\it intermittently} within a very small region. When the sign of the interaction is suddenly switched from repulsive to attractive

S. Sakai, T. Saito, A. Nakamura

On anisotropic lattices with the anisotropy $ξ=a_σ/a_τ$ the following basic parameters are calculated by perturbative method: (1) the renormalization of the gauge coupling in spatial and temporal directions, $g_σ$ and $g_τ$, (2) the $Λ$ parameter, (3) the ratio of the renormalized and bare anisotropy $η=ξ/ξ_B$ and (4) the derivatives of the coupling constant

N. G. Deshpande, Xiao-Gang He, Jian-Qing Shi

We derive several relations between CP violating rate differences $Δ(B\to PV) = Γ(B\to PV) - Γ(\bar B \to \bar P \bar V)$ for charmless $B\to P V$ decays in the Standard Model using SU(3) flavor symmetry. It is found that although the relations between branching ratios of $ΔS = 0$ and $ΔS = -1$ processes are complicated, there are simple relations independen

CDMS Collaboration

The Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for WIMPs via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data give limits on the spin-independent WIMP-nucleon elastic-scattering cross-section that exclude unexplored parameter space above 10 GeV c^{-2}

Guang-jiong Ni, Weimin Zhou, Jun Yan

A particle is always not pure. It always contains hiding antiparticle ingredient which is the essence of special relativity. Accordingly, the Klein-Gordon (KG) equation and Dirac equation are restudied and compared with the Relativistic Stationary Schrödinger Equation (RSSE). When an electron is bound in a Hydrogenlike atom with pointlike nucleus having char

H. Moya-Cessa, A. Vidiella-Barranco, J. A. Roversi, S. M. Dutra

We present a way of treating the problem of the interaction of a single trapped ion with laser beams based on successive aplications of unitary transformations onto the Hamiltonian. This allows the diagonalization of the Hamiltonian, by means of recursive relations, without performing the Lamb-Dicke approximation.

H. Moya-Cessa, A. Vidiella-Barranco, P. Tombesi, J. A. Roversi

We present a scheme to reconstruct the quantum state of a field prepared inside a lossy cavity at finite temperature. Quantum coherences are normally destroyed by the interaction with an environment, but we show that it is possible to recover complete information about the initial state (before interaction with its environment), making possible to reconstruc

M. Paini

Amongst the multitude of state reconstruction techniques, the so-called "quantum tomography" seems to be the most fruitful. In this letter, I will start by developing the mathematical apparatus of quantum tomography and, later, I will explain how it can be applied to various quantum systems.

Lloyd C. L. Hollenberg

Quantum search algorithms are considered in the context of protein sequence comparison in biocomputing. Given a sample protein sequence of length m (i.e m residues), the problem considered is to find an optimal match in a large database containing N residues. Initially, Grover's quantum search algorithm is applied to a simple illustrative case - namely w

M. S. Kim, Jinhyoung Lee

There have been studies on formation of quantum-nonlocal states in spatially separate two cavities. We suggest a nonlocal test for the field prepared in the two cavities. We couple classical driving fields with the cavities where a nonlocal state is prepared. Two independent two-level atoms are then sent through respective cavities to interact off-resonantly

Lorenza Viola, Emanuel Knill, Seth Lloyd

We present control schemes for open quantum systems that combine decoupling and universal control methods with coding procedures. By exploiting a general algebraic approach, we show how appropriate encodings of quantum states result in obtaining universal control over dynamically-generated noise-protected subsystems with limited control resources. In particu

David D. Song, Lucien Hardy

We derive the transformation for the optimal universal quantum anti-cloner which produces two anti-parallel outputs for a single input state. The fidelity is shown to be 2/3 which is same as the measurement fidelity. We consider a probabilistic quantum anti-cloner and show quantum states can be anti-cloned exactly with non-zero probability and its efficiency

Gerald A. Miller

Applications of relativistic light front dynamics to computing wave functions of heavy nuclei are reviewed. The motivation for this is the desire to find wave functions, expressed in terms of the plus-momentum variable, that simplify the analyses of high energy experiments such as deep inelastic scattering, Drell-Yan production, (e,e') and (p,p').Som

M. J. Martins, X. W. Guan

We investigate various aspects of the integrability of the vertex models associated to the $D_n^2$ affine Lie algebra with open boundaries. We first study the solutions of the corresponding reflection equation compatible with the minimal symmetry of this system. We find three classes of general solutions, one diagonal solution and two non-diagonal families w

B. G. Konopelchenko

Using the dbar-problem and dual dbar-problem, we derive bilinear relations which allows us to construct integrable hierarchies in different parametrizations, their Darboux-Bäcklund transformations and to analyze constraints for them ina very simple way. Scalar KP, BKP and CKP hierarchies are considered as examples.

Takayuki Tsuchida

A discrete version of the inverse scattering method proposed by Ablowitz and Ladik is generalized to study an integrable full-discretization (discrete time and discrete space) of the coupled nonlinear Schrödinger equations. The generalization enables one to solve the initial-value problem. Soliton solutions and conserved quantities of the full-discrete syste

Yunbo Zeng

The soliton equations can be factorized by two commuting x- and t-constrained flows. We propose a method to derive N-soliton solutions of soliton equations directly from the x- and t-constrained flows.

Alexander Braverman, Dennis Gaitsgory

Let $G$ be a connected reductive group over $\CC$ and let $G^{\vee}$ be the Langlands dual group. Crystals for $G^{\vee}$ were introduced by Kashiwara as certain ``combinatorial skeletons'' of finite-dimensional representations of $G^{\vee}$. For every dominant integral weight of $G^{\vee}$ Kashiwara constructed a canonical crystal. Other (independen

Oliver Jones, Michael K. Kinyon

A \emph{loop} $(B,\cdot)$ is a set $B$ together with a binary operation $\cdot$ such that (i) for each $a\in B$, the left and right translation mappings $L_{a}:B\to B: x \mapsto a\cdot x$ and $R_{a}:B\to B: x \mapsto x\cdot a$ are bijections, and (ii) there exists a two-sided identity element $1\in B$. Thus loops can be thought of as "nonassociative grou

Sagun Chanillo, Michael K. -H. Kiessling

We study conformally flat surfaces with prescribed Gaussian curvature, described by solutions $u$ of the PDE: $Δu(x)+K(x)\exp(2u(x))=0$, with $K(x)$ the Gauss curvature function at $x\in\RR^2$. We assume that the integral curvature is finite. For radially symmetric $K$ we introduce the notion of a least integrally curved surface, and also the notion of when

C. Duval, V. Ovsienko

Let $(M,g)$ be a pseudo-Riemannian manifold and $F_λ(M)$ the space of densities of degree $λ$ on $M$. We study the space $D^2_{λ,μ}(M)$ of second-order differential operators from $F_λ(M)$ to $F_μ(M)$. If $(M,g)$ is conformally flat with signature $p-q$, then $D^2_{λ,μ}(M)$ is viewed as a module over the group of conformal transformations of $M$. We prove th

Michael Kapovich, John J. Millson

We quantize the bending deformations of n-gon linkages by linearizing the bending fields at a degenerate n-gon to get a representation of the Malcev Lie algebra of the pure braid group. This linearization yields a flat connection on the space of n distinct points on the complex line. We show that the monodromy is (essentially) the Gassner representation.

Xavier Tolsa

Given a doubling measure $μ$ on $R^d$, it is a classical result of harmonic analysis that Calderon-Zygmund operators which are bounded in $L^2(μ)$ are also of weak type (1,1). Recently it has been shown that the same result holds if one substitutes the doubling condition on $μ$ by a mild growth condition on $μ$. In this paper another proof of this result is

Edward Odell, Thomas Schlumprecht

An infinite dimensional notion of asymptotic structure is considered. This notion is developed in terms of trees and branches on Banach spaces. Every countably infinite countably branching tree $\mathcal T$ of a certain type on a space X is presumed to have a branch with some property. It is shown that then X can be embedded into a space with an FDD $(E_i)$

Justin Sawon

A weight system on graph homology was constructed by Rozansky and Witten using a compact hyperkähler manifold. A variation of this construction utilizing holomorphic vector bundles over the manifold gives a weight system on chord diagrams. We investigate these weights from the hyperkähler geometry point of view.

T. Y. Lam

The early papers of Hyman Bass in the late 50s and the early 60s leading up to his pioneering work in algebraic K-theory have played an important and very special role in ring theory and the theory of projective (and injective) modules. In this article, we give a general survey of Bass's fundamental contributions in this early period of his work, and exp

B. L. Cerchiai, G. Fiore, J. Madore

We briefly report our application of a version of noncommutative geometry to the quantum Euclidean space $R^N_q$, for any $N \ge 3$; this space is covariant under the action of the quantum group $SO_q(N)$, and two covariant differential calculi are known on it. More precisely, we describe how to construct in a Cartan `moving-frame formalism' the metric,

Vicente Muñoz, Fran Presas, Ignacio Sols

We use Donaldson's approximately holomorphic techniques to build embeddings of a closed symplectic manifold with symplectic form of integer class in the grassmannians Gr(r,N). We assure that these embeddings are asymptotically holomorphic in a precise sense. We study first the particular case of embeddings in the projective space $CP^N$ obtaining control

Keiji Oguiso

The aim of this note is to study local and global Seshadri constants for a family of smooth surfaces with prescribed polarization. We shall first observe that given $α$ being smaller than the square root of the degree of polarization, the set of local Seshadri constants in the range $(0, α]$ is finite. This in particular implies that the square root of the d

Vladimir V. Kornyak

The cohomology of Lie (super)algebras has many important applications in mathematics and physics. It carries most fundamental ("topological") information about algebra under consideration. At present, because of the need for very tedious algebraic computation, the explicitly computed cohomology for different classes of Lie (super)algebras is known on

Dmitriy S. Kalyuzhniy

We introduce the notion of cascade connection of multiparametric discrete time-invariant linear dynamical systems with unit delay. This allows us to construct the explicit example of conservative realization of a decomposable operator-valued function $θ(z_1, z_2)=θ_2(z_2)θ_1(z_1)$, where $θ_1$ and $θ_2$ are inner operator-valued functions on the unit disk, v

J. M. F. Labastida

A brief summary of the development of perturbative Chern-Simons gauge theory related to the theory of knots and links is presented. Emphasis is made on the progress achieved towards the determination of a general combinatorial expression for Vassiliev invariants. Its form for all the invariants up to order four is reviewed, and a table of their values for al