April 1999 arXiv papers — page 13

Piotr Magierski, Ramon Wyss

In this paper we propose a general framework for deriving the effective interactions for many-body systems. We show how the selfconsistent interaction can be constructed on the quantum level for both local and nonlocal potentials. In particular the relation between the selfconsistent and symmetry restoring interaction is derived. The difference between the t

Toshitaka Tatsumi, Masatomi Yasuhira

A new formulation is presented to treat fluctuations around the kaon condensate. Equation of state (EOS) is given for isothermal and isentropic cases in the heavy-baryon-limit (HBL). The coexistent phase appears in the latter case. The mass-radius relation is given for protoneutron stars and the possibility of the delayed collapse is discussed.

Hirokazu Aiba, Masayuki Matsuo

We propose a new method to analyze fluctuations in the strength function phenomena in highly excited nuclei. Extending the method of multifractal analysis to the cases where the strength fluctuations do not obey power scaling laws, we introduce a new measure of fluctuation, called the local scaling dimension, which characterizes scaling behavior of the stren

Marek Gazdzicki, Waldemar Retyk, Jan Pluta

A method of statistical selection of short lived particles in high multiplicity nucleus-nucleus collisions is discussed.

Hasan Gumral

A formal symplectic structure on RxM is constructed for the unsteady flow of an incompressible viscous fluid on a three dimensional domain M. The evolution equation for the helicity density is expressed via the divergence of the Liouville vector field that generates symplectic dilation. For an inviscid fluid this equation reduces to a conservation law. As an

M. Micu

We found hermitian realizations of the position vector $\vec{r}$, the angular momentum $\vecΛ$ and the linear momentum $\vec{p}$, all behaving like vectors under the $su_q(2)$ algebra, generated by $L_0$ and $L_\pm$. They are used to introduce a $q$-deformed Schr\" odinger equation. Its solutions for the particular cases of the Coulomb and the harmonic o

Jean-Luc Thiffeault, P. J. Morrison

We classify Lie-Poisson brackets that are formed from Lie algebra extensions. The problem is relevant because many physical systems owe their Hamiltonian structure to such brackets. A classification involves reducing all brackets to a set of normal forms, and is achieved partially through the use of Lie algebra cohomology. For extensions of order less than f

Tomek Bartoszynski, Saharon Shelah

The goal of this paper is to prove the theorem in the title.

Tomek Bartoszynski

A bijection from R to R is called an Erdos-Sierpinski mapping if it maps meager sets onto the first category sets and vice versa. We show that there is no Erdos-Sierpinski mapping preserving addition.

Mihail N. Kolountzakis

We consider polygons with the following ``pairing property'': for each edge of the polygon there is precisely one other edge parallel to it. We study the problem of when such a polygon $K$ tiles the plane multiply when translated at the locations $Λ$, where $Λ$ is a multiset in the plane. The pairing property of $K$ makes this question particularly a

Gabriele Vezzosi

We compute generators for the Chow ring of the classifying space of PGL_3 (over the complex numbers) as defined by Totaro. We also find enough relations after inverting 3. We show that this ring is not generated by Chern classes (this is the first example of this kind among classical groups) and prove that Totaro's refined cycle class map to a quotient o

Bruce Hunt

In part I of this paper we constructed certain fibered Calabi-Yaus by a quotient construction in the context of weighted hypersurfaces. In this paper look at the case of K3 fibrations more closely and study the singular fibers which occur. This differs from previous work since the fibrations we discuss have constant modulus, and the singular fibers have tors

J. Piontkowski, A. Van de Ven

The Grassmannians of lines in projective N-space, G(1,N), are embedded by way of the Pl"ucker embedding in the projective space P(\bigwedge^2 C^{N+1}). Let H^l be a general l-codimensional linear subspace in this projective space. We examine the geometry of the linear sections G(1,N)\cap H^l by studying their automorphism groups and list those which are

Selman Akbulut

We construct smooth 4-manifolds that are homeomorphic but not diffeomorphic to the "cusp" and the "fishtail", which are certain thickened singular 2-spheres.

HM Chan, ST Tsou

A loop space formulation of Yang-Mills theory high-lighting the significance of monopoles for the existence of gauge potentials is used to derive a generalization of electric-magnetic duality to the nonabelian theory. The result implies that the gauge symmetry is doubled from SU(N) to $SU(N) \times \widetilde{SU}(N)$, while the physical degrees of freedom re

Zhe Chang

Exponential regularization of orthogonal and Anti-de Sitter (AdS) space is presented based on noncommutative geometry. We show that an adequately adopted noncommutative deformation of geometry makes the holography of higher dimensional quantum theory of gravity and low dimensional theory possible. Detail counting for observable degrees of freedom of quantum

Magnus Holm, Niclas Sandström

New relations involving curvature components for the various connections appearing in the theory of almost product manifolds are given and the conformal behaviour of these connections are studied. New identities for the irreducible parts of the deformation tensor are derived. Some direct physical applications in Kaluza-Klein and gauge theory are discussed.

O. Baerwald, N. D. Lambert, P. C. West

We construct the energy momentum tensor for the bosonic fields of the covariant formulation of the M-theory fivebrane within that formalism. We then obtain the energy for various solitonic solutions of the fivebrane equations of motion.

G. Barenboim, F. Scheck

We show that all the available experimental information involving neutrinos can be accounted for within the framework of already existing models where neutrinos have zero mass at tree level, but obtain a small Dirac mass by radiative corrections.

Nora Brambilla, Antonio Vairo

These lectures contain an introduction to the following topics: 1) Phenomenology of the hadron spectrum; 2) The static Wilson loop in perturbative and in lattice QCD. Confinement and the flux tube formation; 3) Non static properties: effective field theories and relativistic corrections to the quarkonium potential; 4) The QCD vacuum: minimal area law, Abelia

Michael Gronau

The role of penguin amplitudes in CP violating $B$ decays is reviewed, emphasizing recent progress in the analysis of electroweak penguin contributions. It is shown how these terms are included in a model-independent manner when measuring the weak phase $α$ in $B\toππ$ using isospin symmetry, and when determining the phase $γ$ from $B\to Kπ$ applying flavor

S. M. Bilenky, C. Giunti

It is shown that, in the framework of the scheme with three-neutrino mixing and a mass hierarchy, the results of neutrino oscillation experiments imply an upper bound of about 10^{-2} eV for the effective Majorana mass in neutrinoless double-beta decay. The schemes with four massive neutrinos are also briefly discussed.

B. Machet

I study phenomenological aspects of the SU(2)L x U(1) electroweak physics of a Higgs boson transforming like a quark-antiquark pair. A correspondence is established between its flavour content, the hierarchy of quark condensates, and the leptonic decay constants f of pseudoscalar mesons; the Higgs-mesons couplings coming from the symmetry-breaking scalar pot

N. N. Achasov, A. A. Kozhevnikov

The predictions are presented for the diagonal and transition form factors of light hadrons in the time-like region up to the production threshold of an open charm quantum number. The comparison with existing data on the decays of J/psi and psi(2S) mesons into such hadrons shows that some new resonance structures may be present in the mass range between 2 Ge

Rukmani Mohanta, Anjan K. Giri, Mohinder P. Khanna, Muneyuki Ishida

Exclusive weak radiative B meson decays are studied using the covariant oscillator quark model. The branching ratios for the processes B0 to K*0 gamma and B to K* gamma have been estimated. These are in reasonable agreement with the available experimental data. The calculation has been extended to the CKM-suppressed decay processes B- to rho- gamma and Bs to

Rukmani Mohanta, Anjan K. Giri, Mohinder P. Khanna, Muneyuki Ishida

Cabibbo allowed two-body hadronic weak decays of Lambda b baryons are analyzed in the factorization approximation. We use the covariant oscillator quark model to evaluate the heavy to heavy and heavy to light form factors. When applied in the heavy quark limit, our form factors satisfy all the constraints imposed by heavy quark symmetry. The decay rates and

Rukmani Mohanta, Anjan K. Giri, Mohinder P. Khanna, Muneyuki Ishida

Exclusive nonleptonic bottom meson decays are studied in the covariant osillator quark model using the factorization assumption. The main feature of this model is that it can simultaniously be applied to both heavy to heavy and heavy to light transitions, satisfying the constraints of the heavy quark effective theory (HQET) in the appropriate limit. The resu

I. Antoniadis

I discuss possible modifications of gravitation at short distances in string theories with large internal dimensions and low string scale. The modifications are due to the change of Newton's law in the presence of (sub)millimeter-size transverse dimensions, or due to the existence of light scalars with masses as small as 10^{-3} eV, related to the mechan

The OPAL Collaboration, G. Abbiendi et al

A search for pair produced scalar fermions with couplings that violate R-parity has been performed using a data sample corresponding to an integrated luminosity of 56 pb-1 at a centre-of-mass energy of sqrt{s}= 183 GeV collected with the OPAL detector at LEP. An important consequence of R-parity breaking interactions is that the lightest supersymmetric parti

Richard T. Hammond

A theory of gravitation in 4D is presented with strings used in the material action in $U_4$ spacetime. It is shown that the string naturally gives rise to torsion. It is also shown that the equation of motion a string follows from the Bianchi identity, gives the identical result as the Noether conservation laws, and follows a geodesic only in the lowest ord

T. Damour

String theory suggests the existence of gravitational-strength scalar fields ("dilaton" and "moduli") whose couplings to matter violate the equivalence principle. This provides a new motivation for high-precision clock experiments, as well as a generic theoretical framework for analyzing their significance.

M. A. G. Bonilla, C. F. Sopuerta

A four-index tensor is constructed with terms both quadratic in the Riemann tensor and linear in its second derivatives, which has zero divergence for space-times with vanishing scalar curvature. This tensor reduces in vacuum to the Bel-Robinson tensor. Furthermore, the completely timelike component referred to any observer is positive, and zero if and only

Walter Eaves

This paper provides a proof of the proposed Internet standard Transport Level Security protocol using the Gong-Needham-Yahalom logic. It is intended as a teaching aid and hopes to show to students: the potency of a formal method for protocol design; some of the subtleties of authenticating parties on a network where all messages can be intercepted; the desig

J. M. P. Carmelo, J. M. E. Guerra, J. M. B. Lopes dos Santos, A. H. Castro Neto

We use an exact holon and spinon Landau-liquid functional which describes the holon - spinon interactions at all scattering orders, to study correlation functions of integrable multicomponent many-particle problems showing both linear and non-linear energy bands. We consider specific cases when the dominant non-linear band terms are quadratic and apply our r

C. M. Newman, D. L. Stein

A ``persistence'' exponent theta has been extensively used to describe the nonequilibrium dynamics of spin systems following a deep quench: for zero-temperature homogeneous Ising models on the d-dimensional cubic lattice, the fraction p(t) of spins not flipped by time t decays to zero like t^[-theta(d)] for low d; for high d, p(t) may decay to p(infi

Eldad Bettelheim, Benny Lehmann

We simulate reaction-diffusion processes with discrete fields. We use a novel algorithm to simulate different autocatalytic processes with trace densities. Anderson localization with a diffusive potential is studied. A reaction-diffusion process with dynamic localization is discussed in a marketing context.

Artur Sowa

We consider a system of nonlinear equations that extends the Maxwell theory. It was pointed out in a previous paper that symmetric solutions of these equations display properties characteristic of magnetic oscillations. In this paper I study a discrete model of the equations in two dimensions. This leads to the discovery of a new mechanism of vortex lattice

A. Liebsch, S. Goncalves, M. Kiwi

Molecular dynamics simulations of a Xe monolayer sliding on Ag(001) and Ag(111) are carried out in order to ascertain the microscopic origin of friction. For several values of the electronic contribution to the friction of individual Xe atoms, the intra-overlayer phonon dissipation is calculated as a function of the corrugation amplitude of the substrate pot

P. W. Brouwer, C. Mudry, A. Furusaki

It is shown that, in the scaling regime, transport properties of quantum wires with off-diagonal disorder are described by a family of scaling equations that depend on two parameters: the mean free path and an additional continuous parameter. The existing scaling equation for quantum wires with off-diagonal disorder [Brouwer et al., Phys. Rev. Lett. 81, 862

P. W. Brouwer, C. Mudry, A. Furusaki

We compute the density of states (d.o.s.) in N coupled chains with random hopping. At zero energy, the d.o.s. shows a singularity that strongly depends on the parity of N. For odd N, the d.o.s. is proportional to 1/(E (\ln |E|)^3), with and without time-reversal symmetry. For even N, the d.o.s. is proportional to \ln |E| in the presence of time-reversal symm

C. P. Moca, I. Tifrea, M. Crisan

Using the field-theoretical methods we studied the evolution from BCS description of a non-Fermi superconductor to that of Bose-Einstein condensation (BEC) in one loop approximation. We showed that the repulsive interaction between composite bosons is determined by the exponent $α$ of the Anderson propagator in a two dimensional model. For $\a\neq 0$ the cro

V. I. Yukalov, E. P. Yukalova, M. R. Singh

Nonequilibrium processes in semiconductors are considered with highly nonuniform initial densities of charge carriers. It is shown that there exist such distributions of charge densities under which the electric current through a sample displays quite abnormal behaviour flowing against the applied voltage. The appearance of this negative electric current is

Armin Bunde, Shlomo Havlin, Joseph Klafter, Gernot Graff

We consider relaxation processes that exhibit a stretched exponential behavior. We find that in those systems, where the relaxation arises from two competing exponential processes, the size of the system may play a dominant role. Above a crossover time tx that depends logarithmically on the size of the system the relaxation changes from a stretched exponenti

D. Mertz, Y. Ksari, F. Celestini, J. M. Debierre

The magnetic properties of Li_{1-x}Ni_{1+x}O_2 compounds with x ranging between 0.02 and 0.2 are investigated. Magnetization and ac susceptibility measured at temperatures between 2 K and 300 K reveal a high sensitivity to x, the excess Nickel concentration. We introduce a percolation model describing the formation of Ni clusters and use an Ising model to si

Shlomo Havlin, Armin Bunde, Joseph Klafter

We present results on dynamical processes that exhibit a stretched exponential relaxation. When the relaxation is a result of two competing exponential processes, the size of the system, although macroscopic, play a dominant role. There exist a crossover time tx that depends logarithmically on the size of the system, above which, the relaxation changes from

Kentaro Nomura, Daijiro Yoshioka

Transport properties of bilayer quantum Hall systems at $ν=1/q$, where $q$ is an odd integer, are investigated. The edge theory is used for the investigation, since tunneling between the two layers is assumed to occur on the edge of the sample because of the bulk incompressibility. It is shown that in the case of the independent Laughlin state tunneling is i

Ernst Helmut Brandt

The magnetization curve of a type II superconductor in general is hysteretic even when the vortices exhibit no volume or surface pinning. This geometric irreversibility, caused by an edge barrier for flux penetration, is absent only when the superconductor has precisely ellipsoidal shape or is a wedge with a sharp edge where the flux lines can penetrate. A q

A. Yu. Cherny, A. A. Shanenko

A generalized Bogoliubov model of the Bose gas in the ground state is proposed which properly takes into account both the long-range and short-range spatial boson correlations. It concerns equilibrium characteristics and operates with in-medium Schrodinger equations for the pair wave functions of bosons being the eigenfunctions of the second-order reduced de

Brahim Elattari, Rochus Klesse

This paper has been withdrawn by the authors.

Predrag Cvitanovic, Niels Sondergaard, Gergely Palla, Gabor Vattay

A matrix representation of the evolution operator associated with a nonlinear stochastic flow with additive noise is used to compute its spectrum. In the weak noise limit a perturbative expansion for the spectrum is formulated in terms of local matrix representations of the evolution operator centered on classical periodic orbits. The evaluation of perturbat

Giuliano Benenti, Giulio Casati, Italo Guarneri

The statistical properties of a classical electromagnetic field in interaction with matter are numerically investigated on a one-dimensional model of a radiant cavity, conservative and with finite total energy. Our results suggest a trend towards equipartition of energy, with the relaxation times of the normal modes of the cavity increasing with the mode fre

Ashutosh Sharma, Neelima Gupte

We study the phenomenon of intermittency in inhomogeneous lattices of coupled map where inhomogeneity appears in the form of different values of map parameters at adjacent sites.The system exhibits spatiotemporal intermittency in various regions of parameter space.We identify the types of co-dimension two bifurcations which give rise to spatio-temporal or pu

M. J. Kukula, T. Ghosh, A. Pedlar, R. T. Schilizzi

We present 18-cm radio maps of four Seyfert nuclei, Mrk 1, Mrk 3, Mrk 231 and Mrk 463E, made with the European VLBI Network (EVN). Linear radio structures are present in three out of four sources on scales of ~100 pc to ~1 kpc, and the 20-mas beam of the EVN enables us to resolve details within the radio structures on scales of <10 pc. Mrk 3 was also imaged

Andreas Albrecht

Cosmic inflation is the only known mechanism with the potential to explain the very special initial conditions which are required at the early stages of the evolution of our universe. This article outlines my work with Joao Magueijo which attempts to construct an alternative mechanism based on a time-varying speed of light.

Jonathan P. Williams, Philip C. Myers

We present combined single-dish and interferometric CS(2--1) and N2H+(1--0) observations of a compact core in the NW region of the Serpens molecular cloud. The core is starless according to observations from optical to millimeter wavelengths and its lines have turbulent widths and ``infall asymmetry&#39;&#39;. Line profile modeling indicates supersonic inwar

M. Zoccali, S. Cassisi, G. Piotto, G. Bono

We present observational estimates of DV(Bump-HB) in a sample of 28 Galactic Globular Clusters (GGCs) observed by HST. The photometric accuracy and the sizable number of stars measured in each cluster allowed us to single out the RGB Bump both in metal-poor and in metal-rich GGCs. Empirical values are compared with homogeneous theoretical predictions which a

Rosalba Perna, John Raymond, Abraham Loeb

We study the spectral signatures arising from cooling and recombination of an interstellar medium whose equilibrium state has been altered over \sim 100 pc by the radiation of a Gamma-Ray Burst (GRB) and its afterglow. We identify signatures in the line diagnostics which are indicative of a photo-ionized GRB remnant which is \la 5 x 10^4 years old . We estim

Hsiao-Wen Chen, Kenneth M. Lanzetta, Sebastian Pascarelle

The detection and identification of distant galaxies is a prominent goal of observational cosmology because distant galaxies are seen as they were in the distant past and hence probe early galaxy formation, due to the cosmologically significant light travel time. We have sought to identify distant galaxies in very deep spectroscopy by combining a new spectru

R. Pello, J. -P. Kneib, J. -F. Le Borgne, J. Bezecourt

We present the first results on the identification and study of very distant field galaxies in the core of cluster-lenses, using a selection criterium based on both lens modelling and photometric redshifts. We concentrate on two multiple-imaged sources at z=4.05 in the cluster A2390. The 2 objects presented in this paper, namely H3 and H5, were identified th

C. J. Horowitz, Gang Li

Core collapse supernovae are dominated by energy transport from neutrinos. Therefore, some supernova properties could depend on symetries and features of the standard model weak interactions. The cross section for neutrino capture is larger than that for antineutrino capture by one term of order the neutrino energy over the nucleon mass. This reduces the rat

A. D Baute, R. Sala Mayato, J. P. Palao, J. G. Muga

A realization of the concept of &#34;crossing state&#34; invoked, but not implemented, by Wigner, allows to advance in two important aspects of the time of arrival in quantum mechanics: (i) For free motion, we find that the limitations described by Aharonov et al. in Phys. Rev. A 57, 4130 (1998) for the time-of-arrival uncertainty at low energies for certain

D. Petry

The Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) Telescope collaboration is constructing a large Cherenkov telescope (17 m diameter) for the exploration of the gamma-ray energy regime above 10 GeV with high sensitivity. One of the highlights in the science program of this future observatory are the plans for fast follow-up observations of of GRBs. B

P. C. Fragile, G. J. Mathews

We have reconstructed possible orbits for a collection of stars located within 0.5 arcsec of Sgr A*. These orbits are constrained by observed stellar positions and angular proper motions. The construction of such orbits serves as a baseline from which to search for possible deviations due to the unseen mass distribution in the central 1000 AU of the Galaxy.

Washington Taylor, Mark Van Raamsdonk

We investigate further our recent proposal for the form of the matrix theory action in weak background fields. Using Seiberg&#39;s scaling argument we relate the matrix theory action to a low-energy system of many D0-branes in an arbitrary but weak NS-NS and R-R background. The resulting multiple D0-brane action agrees with the known Born-Infeld action in th

Jesús Puente Peñalba

A study of the thermodynamics in IIA Matrix String Theory is presented. The free string limit is calculated and seen to exactly reproduce the usual result. When energies are enough to excite non-perturbative objects like D-particles and specially membranes, the situation changes because they add a large number of degrees of freedom that do not appear at low

Marin Soljacic, Frank Wilczek

We demonstrate, by construction, that simple renormalizable matrix potentials with S_N, as opposed to O(N), symmetry can exhibit an exponentially large number of inequivalent deep local minima.

B. W. Jiang, R. Szczerba, S. Deguchi

This paper reports a detection of the 30 micron emission feature from the C-rich Asymptotic Giant Branch (AGB) star IRAS 03313+6058 based on the ISO-SWS observation. Modeling of the spectral energy distribution shows that this emission starts at about 20 micron and possibly extends to the limit (45 micron) of the observation. By assuming MgS as the carrier,

Jordan Kyriakidis, Daniel Loss, A. H. MacDonald

Pseudospin solitons in double-layer quantum Hall systems can be introduced by a magnetic field component coplanar with the electrons and can be pinned by applying voltages to external gates. We estimate the temperature below which depinning occurs predominantly via tunneling and calculate low-temperature depinning rates for realistic geometries. We discuss t

Haim Goldberg

One-loop diagrams containing a graviton provide a finite contribution to the anomalous magnetic moment $\al$ of a lepton, whether or not the graviton propagates in $n$ large extra compact dimensions. In the present work, the tree graph photoproduction of a graviton, integrated up to an arbitrary cutoff, is shown to violate the Drell-Hearn-Gerasimov sum rule

J. M. Carmona, J. Polonyi, A. Tarancon

We consider scalar field theories in dimensions lower than four in the context of the Wegner-Houghton renormalization group equations (WHRG). The renormalized trajectory makes a non-perturbative interpolation between the ultraviolet and the infrared scaling regimes. Strong indication is found that in two dimensions and below the models with polynomial intera

C. Angelantonj, I. Antoniadis, K. Foerger

We study open descendants of non-supersymmetric type IIB asymmetric (freely acting) orbifolds with zero cosmological constant. A generic feature of these models is that supersymmetry remains unbroken on the brane at all mass levels, while it is broken in the bulk in a way that preserves Fermi-Bose degeneracy in both the massless and massive (closed string) s

Richard Saunders, Ruediger Kneissl, Keith Grainge, William F. Grainger

We present new Ryle Telescope (RT) observations of the Sunyaev Zel&#39;dovich (SZ) decrement from the cluster Abell 773. The field contains a number of faint radio sources that required careful subtraction. We use ASCA observations to measure the gas temperature and a ROSAT HRI image to model the gas distribution. Normalising the gas distribution to fit the

Michel Feldmann

We exhibit a classical model free from any paradox which exactly simulates the spin EPR test. We conclude that Bell&#39;s inequality violation is a strictly classical phenomenon, contrary to a general belief.

M. Hoster, D. Kotschick

We show that surface bundles over surfaces with base and fiber of genus at least 2 have non-vanishing simplicial volume.

Robert P. Langlands, Marc-Andre Lewis, Yvan Saint-Aubin

The partition function with boundary conditions for various two-dimensional Ising models is examined and previously unobserved properties of conformal invariance and universality are established numerically.

Keith Grainge, Michael E. Jones, Guy Pooley, Richard Saunders

We describe our algorithm for measuring the Hubble constant from Ryle Telescope (RT) interferometric observations of the Sunyaev-Zel&#39;dovich (SZ) effect from a galaxy cluster and observation of the cluster X-ray emission. We analyse the error budget in this method: as well as radio and X-ray random errors, we consider the effects of clumping and temperatu

Tristram J. Alexander, Yuri S. Kivshar, Alexander V. Buryak, Rowland A. Sammut

We analyze two-component spatial optical vortex solitons supported by parametric wave mixing processes in a nonlinear bulk medium. We study two distinct cases of such localised waves, namely, parametric vortex solitons due to phase-matched second-harmonic generation in an optical medium with competing quadratic and cubic nonlinear response, and vortex solito

C. S. Kim, D. London, T. Yoshikawa

Time-dependent measurements of the decays B_s^0(t)-->ϕK_s and B_d^0(t) --> K^0 \bar{K}^0 can be used to compare the weak phases of B_d^0-\bar{B}_d^0 mixing and the t-quark contribution to the b->d penguin. Since these two phases are equal in the standard model, any discrepancy would be a sign of new physics, specifically in the b->d flavour-changing neutral

C. Brif, A. Mann

We consider how the conventional spectroscopic and interferometric schemes can be rearranged to serve for reconstructing quantum states of physical systems possessing SU(2) symmetry. The discussed systems include a collection of two-level atoms, a two-mode quantized radiation field with a fixed total number of photons, and a single laser-cooled ion in a two-

Constantin Brif

We study how the behavior of quantum noise, presenting the fundamental limit on the sensitivity of interferometric gravitational-wave detectors, depends on properties of input states of light. We analyze the situation with specially prepared nonclassical input states which reduce the photon-counting noise to the Heisenberg limit. This results in a great redu

I. Bednyakov, L. Labzowsky, G. Plunien, G. Soff

Electroweak radiative corrections to the matrix elements $<ns_{1/2}|{\hat H}_{PNC}|n&#39;p_{1/2}>$ are calculated for highly charged hydrogenlike ions. These matrix elements constitute the basis for the description of the most parity nonconserving (PNC) processes in atomic physics. The operator ${\hat H}_{PNC}$ represents the parity nonconserving relativisti

Juergen Schmidhuber

Is the universe computable? If so, it may be much cheaper in terms of information requirements to compute all computable universes instead of just ours. I apply basic concepts of Kolmogorov complexity theory to the set of possible universes, and chat about perceived and true randomness, life, generalization, and learning in a given universe.

Lov K. Grover

This paper gives a simple proof of why a quantum computer, despite being in all possible states simultaneously, needs at least 0.707 sqrt(N) queries to retrieve a desired item from an unsorted list of items. The proof is refined to show that a quantum computer would need at least 0.785 sqrt(N) queries. The quantum search algorithm needs precisely this many q

Martin Nilsson, Nigel Snoad

In this paper we investigate error-thresholds on dynamics fitness-landscapes. We show that there exists both lower and an upper threshold, representing limits to the copying fidelity of simple replicators. The lower bound can be expressed as a correction term to the error-threshold present on a static landscape. The upper error-threshold is a new limit that

B. G. Sidharth

The time variation of the gravitational constant G in the recently discussed large number cosmologies accounts for the galactic rotational velocity curves without invoking dark matter and also for effects like the precession of the perhelion of Mercury.

Javier Burguete, Hugues Chate, Francois Daviaud, Nathalie Mukolobwiez

We present and analyze experimental results on the dynamics of hydrothermal waves occuring in a laterally-heated fluid layer. We argue that the large-scale modulations of the waves are governed by a one-dimensional complex Ginzburg-Landau equation (CGLE). We determine quantitatively all the coefficients of this amplitude equation using the localized amplitud

M. M. Sharma

The compressibility of nuclear matter has received significant attention in the last decade and a variety of approaches have been employed to extract this fundamental property of matter. Recently, significant differences have emerged between the results of relativistic and non-relativistic calculations of breathing mode giant monopole resonance (GMR). This i

Wang Hui, Sa Ben-Hao, Tai An, Sun Zu-Xun

A hadron and string cascade model, JPCIAE, which is based on LUND string model, PYTHIA event generator especially, is used to study both inclusive photon production and direct photon production in 200A GeV S + Au central collisions. The model takes into account the photon production from the partonic QCD scattering process, the hadronic final-state interacti

Hong-Gang Luo, W. Cassing, Shun-Jin Wang

The dynamical description of correlated nuclear motion is based on a set of coupled equations of motion for the one-body density matrix $ρ(11&#39;;t)$ and the two-body correlation function $c_2(12,1&#39;2&#39;;t)$, which is obtained from the density-matrix hierarchy beyond conventional mean-field approaches by truncating 3-body correlations. The resulting eq

N. Bianchi, E. De Sanctis, M. Mirazita, V. Muccifora

A model based on the hadronic fluctuations of the real photon is developed to describe the total photonucleon and photonuclear cross sections in the energy region above the nucleon resonances. The hadronic spectral function of the photon is derived including the finite width of vector-meson resonances and the quark-antiquark continuum. The shadowing effect i

Raimar Wulkenhaar

For our own education, we reconstruct the Hopf algebra of Connes and Moscovici obtained by the action of vector fields on a crossed product of functions by diffeomorphisms. We extend the realization of that Hopf algebra in terms of rooted trees as given by Connes and Kreimer from dimension one to arbitrary dimension of the manifold. In principle there is no

A. Echeverria-Enriquez, M. C. Munoz-Lecanda, N. Roman-Roy, C. Victoria-Monge

In this review the foundations of Geometric Quantization are explained and discussed. In particular, we want to clarify the mathematical aspects related to the geometrical structures involved in this theory: complex line bundles, hermitian connections, real and complex polarizations, metalinear bundles and bundles of densities and half-forms. In addition, we

Jens Marklof, Zeev Rudnick

We study the ergodic properties of quantized ergodic maps of the torus. It is known that these satisfy quantum ergodicity: For almost all eigenstates, the expectation values of quantum observables converge to the classical phase-space average with respect to Liouville measure of the corresponding classical observable. The possible existence of any exceptiona

Drazen Adamovic

Let $\D$ be the Lie algebra of regular differentialoperators on ${\C} \setminus \{0\}$, and ${\hD}= {\D} + {\C} C$ be the central extension of ${\D}$. Let $W_{1+\infty,-N}$ be the vertex algebra associated to the irreducible vacuum $\hD$-module with the central charge $c=-N$. We show that $W_{1+\infty,-N}$ is a subalgebra of the Heisenberg vertex algebra M(1

Stefan Boettcher, Allon G. Percus

We describe a general-purpose method for finding high-quality solutions to hard optimization problems, inspired by self-organized critical models of co-evolution such as the Bak-Sneppen model. The method, called Extremal Optimization, successively eliminates extremely undesirable components of sub-optimal solutions, rather than ``breeding&#39;&#39; better co

Maxim Kontsevich

This paper is dedicated to the memory of Moshe Flato, and will appear in Lett. Math. Phys. 48 (1) It became clear during last 5-6 years that the algebraic world of associative algebras (abelian categories, triangulated categories, etc) has many deep connections with the geometric world of two-dimensional surfaces. One of manifestations of this is Deligne&#39

Jean-Claude Hausmann

We consider the problem of existence of representations of topological groupoids on a principal bundle and the classification of such representations up to gauge transformation. Such representations naturally occur in various contexts such as gauge theory, lattice gauge fields, equivariant bundles, etc. In the course of the proofs, some new facts about Milno

Alexander Dvorsky, Siddhartha Sahi

We construct an explicit realization of a minimal representation of G, where G is the conformal group of a real Jordan algebra N. We characterize spherical vectors for these representation and prove that they are closely related to the Bessel K-function $K_τ(z)$. The resulting construction can be used to study tensor powers of the minimal representation and

B. J. J. Moonen, Yu. G. Zarhin

In this paper we study Hodge classes on complex abelian varieties. We prove some general results that allow us, in certain cases, to compute the Hodge group of a product abelian variety $X = X_1 \times X_2$ once we know the Hodge groups of the two factors. Using these results we can compute the Hodge groups of all abelian varieties of dimension $\leq 5$. We

Zhe Chang

The quantum Anti-de Sitter (AdS) group and quantum AdS space is discussed. Ways of getting the quantum AdS group from real forms of quantum orthogonal group are presented. Differential calculus on the quantum AdS space are also introduced. In particular, reality of differential calculus are given. We set up explicit relationships between quantum group and qu