May 2005 arXiv papers — page 2

Michele Della Morte, Roland Hoffmann, Francesco Knechtli, Rainer Sommer

We present a new normalization condition for the axial current, derived from the PCAC relation with non-vanishing quark mass. This condition is expected to reduce mass effects in the chiral extrapolation of the results for the normalization factor Z_A. The application to the two-flavor theory with improved Wilson fermions shows that this expectation is indee

Heavy Flavor Averaging Group

This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of winter 2005 conferences. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages

B. Aubert, BABAR Collaboration

We report on the search for the rare decays $B^+ \to D^{(*)+} K^0_{s}$ in approximately 226 million $Y(\rm 4S)\to b\bar{B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy $B$ factory at SLAC. We do not observe any significant signal and we set 90% confidence level upper limits on the branching fractions, ${\ensuremath {{\cal B}(\Bp{

J. Schümann

We summarize recent results of baryonic B decays from Belle and BaBar. The results from Belle are based on 140 /fb and results from BaBar are based on 81 /fb of data collected at the Upsilon(4S) resonance at KEKB or PEPII respectively. We report the results of two- and three-body baryonic B decays as well as searches for pentaquarks. The three-body baryonic

The Belle Collaboration, D. Mohapatra

We report the results of a search for the flavor-changing neutral current process b --> d gamma using a sample of 275 million B meson pairs accumulated by the Belle detector at KEKB. We find no significant signal for the exclusive decays B- --> rho- gamma, B0B --> rho0 gamma, or B0B --> omega gamma. Assuming an isospin relation between the three modes, we se

Yasushi Mino

We propose a new metric perturbation scheme under a possible constraint of the gauge conditions in which we obtain a physically expected prediction of the orbital evolution caused by the MiSaTaQuWa self-force. In this new scheme of a metric perturbation, an adiabatic approximation is applied to both the metric perturbation and the orbit. As a result, we are

Yasushi Mino

We review a recent theoretical progress in the so-called self-force problem of a general relativistic two-body system. Although a two-body system in Newtonian gravity is a very simple problem, some fundamental issues are involved in relativistic gravity. Besides, because of recent projects for gravitational wave detection, it comes to be possible to see thos

Fu-Wen Shu, You-Gen Shen

The Newman-Penrose formalism is used to deal with the quasinormal modes(QNM's) of Rarita-Schwinger perturbations outside a Reissner-Nordström black hole. We obtain four kinds of possible expressions of effective potentials, which are proved to be of the same spectra of quasinormal mode frequencies. The quasinormal mode frequencies evaluated by the WKB po

Malcolm Anderson

The gravitational back-reaction on a certain type of rigidly-rotating cosmic string loop, first discovered by Allen, Casper and Ottewill, is studied at the level of the weak-field approximation. The near-field metric perturbations are calculated and used to construct the self-acceleration vector of the loop. Although the acceleration vector is divergent at t

Vedad Pasic, Dmitri Vassiliev

A classical pp-wave is a 4-dimensional Lorentzian spacetime which admits a nonvanishing parallel spinor field; here the connection is assumed to be Levi-Civita. We generalise this definition to metric compatible spacetimes with torsion and describe basic properties of such spacetimes. We use our generalised pp-waves for constructing new explicit vacuum solut

Orest Hrycyna, Marek Szydlowski

FRW cosmologies with conformally coupled scalar fields are investigated in a geometrical way by the means of geodesics of the Jacobi metric. In this model of dynamics, trajectories in the configuration space are represented by geodesics. Because of the singular nature of the Jacobi metric on the boundary set $\partial\mathcal{D}$ of the domain of admissible

Ding-fang Zeng, Yi-hong Gao

We point out that $Λ$CDM cosmology has an ignored assumption. That is, the $Λ$ component of the universe moves synchronously with ordinary matters on Hubble scales. If cosmological constant is vacuum energy, this assumption may be very difficult to be understood. We then propose a new mechanism which can explain the accelerating recession of super-novaes. Th

Dmitry Mogilevsky, Sean Keller

Modern high-performance computing relies heavily on the use of commodity processors arranged together in clusters. These clusters consist of individual nodes (typically off-the-shelf single or dual processor machines) connected together with a high speed interconnect. Using cluster computation has many benefits, but also carries the liability of being failur

Michael Soltys

We show that Csanky's fast parallel algorithm for computing the characteristic polynomial of a matrix can be formalized in the logical theory LAP, and can be proved correct in LAP from the principle of linear independence. LAP is a natural theory for reasoning about linear algebra introduced by Cook and Soltys. Further, we show that several principles of

Merce Llabres, Jairo Rocha, Francesc Rossello, Gabriel Valiente

Compatibility of phylogenetic trees is the most important concept underlying widely-used methods for assessing the agreement of different phylogenetic trees with overlapping taxa and combining them into common supertrees to reveal the tree of life. The notion of ancestral compatibility of phylogenetic trees with nested taxa was introduced by Semple et al in

Tom Schrijvers, Maria Garcia de la Banda, Bart Demoen, Peter J. Stuckey

Taylor introduced a variable binding scheme for logic variables in his PARMA system, that uses cycles of bindings rather than the linear chains of bindings used in the standard WAM representation. Both the HAL and dProlog languages make use of the PARMA representation in their Herbrand constraint solvers. Unfortunately, PARMA's trailing scheme is conside

Gang Lu, E. B. Tadmor, Efthimios Kaxiras

We present a multiscale modeling approach that concurrently couples quantum mechanical, classical atomistic and continuum mechanics simulations in a unified fashion for metals. This approach is particular useful for systems where chemical interactions in a small region can affect the macroscopic properties of a material. We discuss how the coupling across di

S. M. Frolov, D. J. Van Harlingen, V. V. Bolginov, V. A. Oboznov

We study Superconductor-Ferromagnet-Superconductor (Nb-Cu0.47 Ni0.53-Nb) Josephson junctions with spatial variations in the barrier thickness. Critical current vs. magnetic flux diffraction patterns indicate that the critical current density changes sign along the width of the junctions, creating interfaces between 0 and pi junction regions around which spon

S. N. Dorogovtsev, A. V. Goltsev, J. F. F. Mendes

We study pair correlations in cooperative systems placed on complex networks. We show that usually in these systems, the correlations between two interacting objects (e.g., spins), separated by a distance $\ell$, decay, on average, faster than $1/(\ell z_\ell)$. Here $z_\ell$ is the mean number of the $\ell$-th nearest neighbors of a vertex in a network. Thi

N. Shah, A. V. Lopatin, V. M. Vinokur

We study the low temperature magnetoresistance of dirty thin films and quantum wires close to a quantum phase transition from a superconducting to normal state, induced by applying a parallel magnetic field. We find that the different corrections (Aslamazov-Larkin, density of states and Maki-Thompson) to the normal state conductivity, coming from the superco

Giovanni Cennini, Carsten Geckeler, Gunnar Ritt, Martin Weitz

We have studied the interference of a variable number of independently created $m_F=0$ microcondensates in a CO$_{2}$-laser optical lattice. The observed average interference contrast decreases with condensate number N. Our experimental results agree well with the predictions of a random walk model. While the exact result can be given in terms of Kluyver&#39

G. Zarand

In this lecture note we focus our attention to quantum dot systems where exotic strongly correlated behavior develops due to the presence of orbital or charge degrees of freedom. After giving a concise overview of the theory of transport and Kondo effect through a single electron transistor, we discuss how SU(4) Kondo effect develops in dots having orbitally

T. Kimura, J. Hamrle, Y. Otani

We demonstrate the method to calculate the spatial distributions of the spin current and accumulation in the multi-terminal ferromagnetic/nonmagnetic hybrid structure using an approximate electro-transmission line. The analyses based on the obtained equation yield the results in good agreement with the experimental ones. This implies that the method allows u

I. Sheikin, H. Jin, R. Bel, K. Behnia

The Nernst coefficient of CeCoIn5 displays a distinct anomaly at H_K ~ 23 T. This feature is reminiscent of what is observed at 7.8 T in CeRu2Si2, a well-established case of metamagnetic transition. New frequencies are observed in de Haas-van Alphen oscillations when the field exceeds 23 T, which may indicate a modification of the Fermi surface at this field

G. Ghigo, D. Botta, A. Chiodoni, L. Gozzelino

The microwave properties of polycrystalline MgB2 thin films prepared by the so-called in-situ method are investigated. The characterization of the films at microwave frequencies was obtained by a coplanar resonator technique. The analysis of the experimental data results in the determination of penetration depth, surface impedance and complex conductivity. T

Nadav Katz, Eitan Rowen, Roee Ozeri, Nir Davidson

We study the collisional decay of a strongly driven Bose-Einstein condensate oscillating between two momentum modes. The resulting products of the decay are found to strongly deviate from the usual s-wave halo. Using a stochastically seeded classical field method we simulate the collisional manifold. These results are also explained by a model of colliding B

M. Lazrek, D. J. Bicout, S. Jaziri, E. Kats

The paper deals with a simple three sites model for charge transfer phenomena in an one-dimensional donor (D) - bridge (B) - acceptor (A) system coupled with vibrational dynamics of the B site. It is found that in a certain range of parameters the vibrational coupling leads to an enhancement of the effective donor - acceptor electronic coupling as a result o

A. B. Mutiara

At the present paper we have computed non-ergodicity paramater from Molecular Dynamics (MD) Simulation data after the mode-coupling theory (MCT) for a glass transition. MCT of dense liquids marks the dynamic glass-transition through a critical temperature $T_c$ that is reflected in the temperature-dependence of various physical quantities. Here, molecular dy

N. R. Cooper, E. H. Rezayi, S. H. Simon

We show that dipolar interactions have dramatic effects on the groundstates of rotating atomic Bose gases in the weak interaction limit. With increasing dipolar interaction (relative to the net contact interaction), the mean-field, or high filling fraction, groundstate undergoes a series of transitions between vortex lattices of different symmetries: triangu

David A. Kessler, Ioannis G. Kevrekidis, Ligang Chen

In the context of equation-free computation, we devise and implement a procedure for using short-time direct simulations of a KPZ type equation to calculate the self-similar solution for its ensemble averaged correlation function. The method involves "lifting" from candidate pair-correlation functions to consistent realization ensembles, short bursts

Olaf Lenz, Friederike Schmid

We present a simple coarse-grained bead-and-spring model for lipid bilayers. The system has been developed to reproduce the main (gel-liquid) transition of biological membranes on intermediate length scales of a couple of nanometres and is very efficient from a computational point of view. For the solvent environment, two different models are proposed. The f

J. Scola, A. Pautrat, C. Goupil, L. Mechin

We report the first measurements of the voltage noise in the surface superconductivity state of a type-II superconductor. We present strong evidences that surface vortices generates surface current fluctuations whose magnitude can be modified by the pinning ability of the surface. Simple two-stage mechanism governed by current conservation appears to describ

Eros Mariani, Ady Stern

In this paper we derive the dispersion relation of the surface waves at the interfaces between Mott insulating and Superfluid phases for confined Bose-Einstein Condensates. We then calculate their contribution to the heat capacity of the system and show how its low temperature scaling allows an experimental test of the existence and properties of Mott Insula

Min-Chul Cha

We have investigated the correlation functions of interacting bosons at the generic superfluid-insulator transition, a prototypical quantum phase transition, in two dimensions in the spherical limit. Unexpectedly the spatial correlation functions show non-power-law behavior consisting of two parts: short-range correlation due to the particle-hole pair excita

Narihisa Matsumoto, Daisuke Ide, Masataka Watanabe, Masato Okada

Synaptic connections are known to change dynamically. High-frequency presynaptic inputs induce decrease of synaptic weights. This process is known as short-term synaptic depression. The synaptic depression controls a gain for presynaptic inputs. However, it remains a controversial issue what are functional roles of this gain control. We propose a new hypothe

Andrea Crisanti, Luca Leuzzi

We present the detailed analysis of the spherical s+p spin glass model with two competing interactions: among p spins and among s spins. The most interesting case is the 2+p model with p > 3 for which a very rich phase diagram occurs, including, next to the paramagnetic and the glassy phase represented by the one step replica symmetry breaking ansatz typical

Keiji Yada, Hiroshi Kontani

We analyze the ``normal electronic states'' of Na_{0.35}CoO_2 based on the effective d-p model with full d-orbital freedom using the fluctuation-exchange (FLEX) approximation. They sensitively depend on the topology of the Fermi surfaces, which changes as the crystalline electric splitting (CES) due to the trigonal deformation. We succeed in reproduc

M. Combescot, O. Betbeder-Matibet

This letter assigns the Faraday rotation in photoexcited semiconductors to ``Pauli interactions'', \emph{i}. \emph{e}., carrier exchanges, between the real excitons present in the sample and the virtual excitons coupled to the $σ_{\pm}$ parts of a linearly polarized light. While \emph{direct Coulomb} interactions scatter bright excitons into bright e

S. Melchionna, S. Succi, J. -P. Hansen

A lattice version of the Fokker-Planck equation (FPE), accounting for dissipative interactions, not resolved on the molecular scale, is introduced. The lattice FPE is applied to the study of electrorheological transport of a one-dimensional charged fluid, and found to yield quantitative agreement with a recent analytical solution. Future extensions, includin

V. Orlyanchik, Z. Ovadyahu

The combination of strong disorder and many-body interactions in Anderson insulators lead to a variety of intriguing non-equilibrium transport phenomena. These include slow relaxation and a variety of memory effects characteristic of glasses. Here we show that when such systems are driven with sufficiently high current, and in liquid helium bath, a peculiar

L. Canet, H. Chaté, B. Delamotte, I. Dornic

We apply the non-perturbative renormalization group method to a class of out-of-equilibrium phase transitions (usually called ``parity conserving'' or, more properly, ``generalized voter'' class) which is out of the reach of perturbative approaches. We show the existence of a genuinely non-perturbative fixed point, i.e. a critical point which

P. Pierobon, A. Parmeggiani, F. von Oppen, E. Frey

We study the dynamics of the totally asymmetric exclusion process with open boundaries by phenomenological theories complemented by extensive Monte-Carlo simulations. Upon combining domain wall theory with a kinetic approach known as Boltzmann-Langevin theory we are able to give a complete qualitative picture of the dynamics in the low and high density regim

M. Mobilia, B. Schmittmann, R. K. P. Zia

We present the exact solution for the full dynamics of a nonequilibrium spin chain and its dual reaction-diffusion model, for arbitrary initial conditions. The spin chain is driven out of equilibrium by coupling alternating spins to two thermal baths at different temperatures. In the reaction-diffusion model, this translates into spatially alternating rates

Carlos A. Olano

From an analysis of the sky and velocity distributions of the high-velocity clouds (HVCs) we show that the majority of the HVCs has a common origin. We conclude that the HVCs surround the Galaxy, forming a metacloud of 300 kpc in size and with a mass of 3 10^9 M_sun, and that they are the product of a powerful ``superwind'' (about 10^58 ergs), which

K. N. Allers, D. T. Jaffe, J. H. Lacy, B. T. Draine

Using the Texas Echelon Cross Echelle Spectrograph (TEXES) we mapped emission in the H_2 v = 0-0 S(1) and S(2) lines toward the Orion Bar PDR at 2" resolution. We also observed H_2 v = 0-0 S(4) at selected points toward the front of the PDR. Our maps cover a 12" by 40" region of the bar where H_2 ro-vibrational lines are bright. The distributions

Arcadio Poveda, Christine Allen, Alejandro Hernandez-Alcantara

In the course of a search for common proper motion binaries, in the Jones & Walker (JW) catalogue of proper motions in the Orion Nebula Cluster, we came across several faint stars with proper motions larger than one arcsecond per century and probabilities of membership P larger than 0.90. Such stars are interesting because they could be low-mass runaway star

Alberto Buzzoni

We present here a new set of evolutionary population synthesis models for template galaxies along the Hubble morphological sequence. The models, that account for the individual evolution of the bulge, disk, and halo components, provide basic morphological features, along with bolometric luminosity and color evolution (including Johnson/Cousins "UBVRcIcJH

D. A. Boboltz, K. B. Marvel

We present observational evidence that the OH/IR star OH 12.8-0.9 is the fourth in a class of objects previously dubbed "water-fountain" sources. Using the Very Long Baseline Array, we produced the first images of the water maser emission associated with OH 12.8-0.9. We find that the masers are located in two compact regions with an angular separatio

I. Perez, I. Marquez, K. Freeman, R. Fux

This paper presents surface photometry (B,V, I, J, H, K) and H_alpha rotation curves of 27 isolated spiral galaxies. The final goal is to obtain the mass distribution of a sample of isolated spiral galaxies in order to model their gas kinematics. This is then compared to the observed rotation curve, to determine the necessity of a dark halo in the inner part

A. C. Gupta, U. C. Joshi

In the present paper we report the detection of intra-night variability in some of the RQQSOs and one LDQ. To study intra-night variability, we carried out photometric monitoring of seven RQQSOs and one LDQ in Johnson V-passband using 1.2 meter optical/IR telescope at Gurushikhar, Mount Abu, India. Observations were made in nine nights during the first half

Margarita E. Sharina, Thomas H. Puzia, Dmitry I. Makarov

Fifty-seven nearby low surface brightness dwarf galaxies were searched for globular cluster candidates (GCCs) using Hubble Space Telescope WFPC2 imaging in V and I. The sample consists of 18 dwarf spheroidal (dSph), 36 irregular (dIrr), and 3 "transition" type (dIrr/dSph) galaxies with angular sizes less than 3.7 kpc situated at distances 2-6 Mpc in

C. Graziani, D. Q. Lamb, T. Q. Donaghy

HETE-II and BeppoSAX have produced a sample of GRBs and XRFs with known redshifts and $E_{pk}$. This sample provides four important empirical constraints on the nature of the source jets: Log $E_{iso}$ is approximately uniformly distributed over several orders of magnitude; the inferred prompt energy Log $E_γ$ is narrowly distributed; the Amati relation hold

M. Rejkuba, L. Greggio, W. E. Harris, G. L. H. Harris

Using the HST Wide Field Camera of the Advanced Camera for Surveys (ACS), we have obtained deep (V,I) photometry of an outer-halo field in NGC 5128, to a limiting magnitude of I~29. Our photometry directly reveals the core helium-burning stellar population (the ``red clump'' or horizontal branch) in a giant E/S0 galaxy for the first time. The color-m

Stefan Andersson, Geert-Jan Kroes, Ewine F. van Dishoeck

Ultraviolet irradiation of ice is of great interest for understanding the chemistry in both atmospheric and astrophysical environments. In interstellar space, photodissociation of H2O molecules can be a driving force behind the chemistry on icy dust grains in dense, cold molecular clouds even though the flux of UV photons is extremely low. The mechanisms of

E. Babichev, V. Dokuchaev, Yu. Eroshenko

The stationary, spherically symmetric accretion of dark energy onto a Schwarzschild black hole is considered in terms of relativistic hydrodynamics. The approximation of an ideal fluid is used to model the dark energy. General expressions are derived for the accretion rate of an ideal fluid with an arbitrary equation of state p=p(ρ) onto a black hole. The bl

L. Cerrigone, G. Umana, C. Trigilio

In the last few years we have started a systematic study aimed at detecting very young Planetary Nebulae (YPNs). The project, based on both radio (multi-frequency and high resolution) and optical observations, has already provided interesting results, including the identification of new YPNs and the observation, for the first time in PN in this very early ph

S. Giacintucci, T. Venturi, G. Brunetti, S. Bardelli

We present a new detailed multiband study of the merging cluster A3562, in the core of the Shapley Concentration Supercluster. We analyzed new, low frequency radio data performed at 240 MHz, 332 MHz and 610 MHz with the Giant Metrewave Radio Telescope (GMRT). The new GMRT data allowed us to carry out a detailed study of the radio halo at the centre of A3562,

N. Markova, J. Puls, S. Scuderi, H. Markov

We investigate the line-profile variability (lpv) of H-alpha for a large sample of O-type supergiants. We used the Temporal Variance Spectrum (TVS) analysis, developed by Fullerton et al 1996 and modified by us to take into account the effects of wind emission. By means of a comparative analysis we put a number of constraints on the properties of the variabi

Zhe Chang, Shao-Xia Chen, Cheng-Bo Guan, Chao-Guang Huang

We discuss the threshold anomaly in ultra-high energy cosmic ray physics by assuming that the matter world just be perturbation of a de Sitter universe, which is consistent with the recent astronomical observations: about two thirds of the whole energy in the universe is contributed by a small positive cosmological constant. One-particle states are presented

Motoyuki Saijo

We investigate the rotational core collapse of a rapidly rotating relativistic star by means of a 3+1 hydrodynamical simulations in conformally flat spacetime of general relativity. We concentrate our investigation to the bounce of the rotational core collapse, since potentially most of the gravitational waves from it are radiated around the core bounce. The

Bjoern S. Schmekel

The electromagnetic radiation of a rotating relativistic electron layers is studied numerically using particle-in-cell simulation. The results of the simulation confirm all relevant scaling properties predicted by theoretical models. These models may turn out to be important for the understanding of the coherent synchrotron radiation (CSR) instability that m

Hugh Merz, Ue-Li Pen, Hy Trac

We present a new parallel PM N-body code named PMFAST that is freely available to the public. PMFAST is based on a two-level mesh gravity solver where the gravitational forces are separated into long and short range components. The decomposition scheme minimizes communication costs and allows tolerance for slow networks. The code approaches optimality in sev

Fei Zhou

I study the influence of fermion-boson conversion near Feshbach resonances on Mott states of Cooper pairs and demonstrate possible invasion of superfluidity. The quantum dynamics of Fermi-Bose gases is studied using both an effective coupled $U(1)\otimes U(1)$ quantum rotor Hamiltonian and a coupled XXZ $\otimes$ XXZ spin Hamiltonian. I also point out two di

M. Novaes

The semiclassical propagation of spin coherent states is considered in complex phase space. For two time-independent systems we find the appropriate classical trajectories and show that their combined contributions are able to describe quantum interference with great accuracy. Not only the modulus but also the phase of the quantum propagator, both dynamical

S. Biermann, L. de' Medici, A. Georges

We study a multi-band Hubbard model in its orbital selective Mott phase, in which localized electrons in a narrow band coexist with itinerant electrons in a wide band. The low-energy physics of this phase is shown to be closely related to that of a generalized double-exchange model. The high-temperature disordered phase thus differs from a Fermi liquid, and

Sebastian Bustingorry, Leticia Cugliandolo, Daniel Dominguez

We study the relaxational dynamics of flux lines in high-temperature superconductors with random pinning using Langevin dynamics. At high temperatures the dynamics is stationary and the fluctuation dissipation theorem (FDT) holds. At low temperatures the system does not equilibrate with its thermal bath: a simple multiplicative aging is found, the FDT is vio

Boaz Tsaban

The Diffie-Hellman key agreement protocol is based on taking large powers of a generator of a prime-order cyclic group. Some generators allow faster exponentiation. We show that to a large extent, using the fast generators is as secure as using a randomly chosen generator. On the other hand, we show that if there is some case in which fast generators are les

Nathan M. Dunfield, Sergei Gukov, Jacob Rasmussen

We propose a framework for unifying the sl(N) Khovanov-Rozansky homology (for all N) with the knot Floer homology. We argue that this unification should be accomplished by a triply graded homology theory which categorifies the HOMFLY polynomial. Moreover, this theory should have an additional formal structure of a family of differentials. Roughly speaking, t

J. C. Sankey, I. N. Krivorotov, S. I. Kiselev, P. M. Braganca

The spin-transfer torque from a DC spin-polarized current can generate highly-coherent magnetic precession in nanoscale magnetic-multilayer devices. By measuring linewidths of spectra from the resulting resistance oscillations, we argue that the coherence time can be limited at low temperature by thermal deflections about the equilibrium magnetic trajectory,

Ben Webster

Let X be the Dynkin diagram of a symmetrizable Kac-Moody algebra, and X_0 a subgraph with all vertices of degree 1 or 2. Using the crystal structure on the components of quiver varieties for X, we show that if we expand X by extending X_0, the branching multiplicities and tensor product multiplicities stabilize, provided the weights involved satisfy a condit

Mariana Grana, Jan Louis, Daniel Waldram

We consider type II string theory in space-time backgrounds which admit eight supercharges and can be characterized by the existence of an SU(3) x SU(3) structure. We show that the couplings of such backgrounds strongly resemble the couplings of four-dimensional N=2 supergravities and precisely coincide with the N=2 couplings after an appropriate Kaluza-Klei

Hironobu Kihara, Makoto Sakaguchi, Yukinori Yasui

We study the spectrum of the scalar Laplacian on the five-dimensional toric Sasaki-Einstein manifolds Y^{p,q}. The eigenvalue equation reduces to Heun's equation, which is a Fuchsian equation with four regular singularities. We show that the ground states, which are given by constant solutions of Heun's equation, are identified with BPS states corres

I. Ya. Aref'eva, A. S. Koshelev, S. Yu. Vernov

Cosmological consequences of adding the Cold Dark Matter (CDM) to the exactly solvable stringy Dark Energy (DE) model are investigated. The model is motivated by the consideration of our Universe as a slowly decaying D3-brane. The decay of this D-brane is described in the String Field Theory framework. Stability conditions of the exact solution with respect

Arunava Bhadra, Kabita Sarkar

It is shown that among the four classes of the static spherically symmetric solution of the vacuum Brans-Dicke theory of gravity only two are really independent. Further by matching exterior and interior (due to physically reasonable spherically symmetric matter source) scalar fields it is found that only Brans class I solution with certain restriction on so

Tao Han, Heather E. Logan, Biswarup Mukhopadhyaya, Raghavendra Srikanth

We investigate the sources of neutrino mass generation in Little Higgs theories, by confining ourselves to the "Littlest Higgs" scenario. Our conclusion is that the most satisfactory way of incorporating neutrino masses is to include a lepton-number violating interaction between the scalar triplet and lepton doublets. The tree-level neutrino masses g

Maciej Trzetrzelewski

We present a systematic method to express all $su(N)$ invariant tensors in terms of forests i.e. products of tree tensors.

S. Ostapchenko

Non-linear effects in hadronic interactions are treated by means of enhanced pomeron diagrams, assuming that pomeron-pomeron coupling is dominated by soft partonic processes. It is shown that the approach allows to resolve a seeming contradiction between realistic parton momentum distributions, measured in deep inelastic scattering experiments, and the energ

D. Emmanuel-Costa, R. Gonzalez Felipe

We look for the minimal particle content which is necessary to add to the standard model in order to have a complete unification of gauge couplings and gravity at the weakly coupled heterotic string scale. Using the current precision electroweak data, we find that the presence of a vector-like fermion at an intermediate scale and a non-standard hypercharge n

F. P. Laussy, M. M. Glazov, A. V. Kavokin, D. M. Whittaker

A theoretical investigation is presented of the statistics of excitons in quantum dots (QDs) of different sizes. A formalism is developed to build the exciton creation operator in a dot from the single exciton wavefunction and it is shown how this operator evolves from purely fermionic, in case of a small QD, to purely bosonic, in case of large QDs. Nonlinea

Takanori Nagakura, Kazuyuki Omukai

We study the evolution of gas in HII regions around the first stars after the death of the exciting stars. If the first star in a small halo dies without supernova (SN), subsequent star formation is possible in the same halo. We thus investigate the effect of ionization of the gas on subsequent star formation within small halos in the early universe using on

Angel Ballesteros, Francisco J. Herranz, Orlando Ragnisco

A family of classical integrable systems defined on a deformation of the two-dimensional sphere, hyperbolic and (anti-)de Sitter spaces is constructed through Hamiltonians defined on the non-standard quantum deformation of a sl(2) Poisson coalgebra. All these spaces have a non-constant curvature that depends on the deformation parameter z. As particular case

Johannes Rueckert, Dierk Schleicher

The Newton map N_f of an entire function f turns the roots of f into attracting fixed points. Let U be the immediate attracting basin for such a fixed point of N_f. We study the behavior of N_f in a component V of C\U. If V can be surrounded by an invariant curve within U and satisfies the condition that each point in the extended plane has at most finitely

A. Buzdin, S. Tollis, J. Cayssol

We demonstrate that in a superconducting multilayered system with alternating interlayer coupling a new type of nonuniform superconducting state can be realized under in-plane magnetic field. The Zeeman effect in this state is compensated by the energy splitting between bonding and antibonding levels. Such compensation mechanism at low temperature leads to t

C. Schwanenberger

Recent results from searches for physics beyond the Standard Model (SM) in electron/positron-proton collisions at HERA at center-of-mass energies of 300 and 320 GeV are presented. They were performed on a data sample collected in the period 1994-2004 by the H1 and ZEUS collaborations. The data have been analysed searching for leptoquarks, light gravitinos in

P. Fleurat-Lessard, T. Ziegler

The free energy profile of a reaction can be estimated in a molecular-dynamics approach by imposing a mechanical constraint along a reaction coordinate (RC). Many recent studies have shown that the temperature can greatly influence the path followed by the reactants. Here, we propose a practical way to construct the minimum energy path directly on the free e

J. A. Grifols

In a medium composed of scalar particles with non-zero mass, the range of Van-der-Waals-type scalar mediated interactions among nucleons becomes infinite when the medium makes a transition to a Bose-Einstein condensed phase. We explore this phenomenon in an astrophysical context. Namely, we study the effect of a scalar dark matter background on the equilibri

Dmitry Borisyuk, Alexander Kobushkin

We study the target normal spin asymmetry for the reaction $ep \to ep$ at electron energy up to few GeV in the laboratory frame. The asymmetry is proportional to the imaginary part of the reaction scattering amplitude. To estimate the imaginary part of the amplitude we use the unitarity relation and saturate the intermediate hadron states by the proton and r

Krzysztof Gawryluk, Mirosław Brewczyk, Kazimierz Rzcażewski

We study the instability of a doubly quantized vortex topologically imprinted on $^{23}$Na condensate, as reported in recent experiment [Phys. Rev. Lett. \textbf{93}, 160406 (2004)]. We have performed numerical simulations using three-dimensional Gross-Pitaevskii equation with classical thermal noise. Splitting of a doubly quantized vortex turns out to be a

German Izquierdo, Diego Pavon

We explore the thermodynamics of dark energy taking into account the existence of the observer's event horizon in accelerated universes. Except for the initial stage of Chaplygin gas dominated expansion, the generalized second law of gravitational thermodynamics is fulfilled and the temperature of the phantom fluid results positive. This substantially ex

J. Flouquet, G. Knebel, D. Braithwaite, D. Aoki

The interplay of magnetism and unconventional superconductivity (d singlet wave or p triplet wave) in strongly correlated electronic system (SCES) is discussed with recent examples found in heavy fermion compounds. A short presentation is given on the formation of the heavy quasiparticle with the two sources of a local and intersite enhancement for the effec

Joni J. P. Virtanen, Rami Vainio

We report studies on first-order Fermi acceleration in parallel modified shock waves with a large scattering center compression ratio expected from turbulence transmission models. Using a Monte Carlo technique we have modeled particle acceleration in shocks with a velocity ranging from nonrelativistic to ultrarelativistic and a thickness extending from nearl

Bin Xu

In this paper, we give the sharp estimates for the degree of symmetry and the semi-simple degree of symmetry of certain four dimensional fiber bundles by virtue of the rigidity theorem of harmonic maps due to Schoen and Yau. As a corollary of this estimate, we compute the degree of symmetry and the semi-simple degree of symmetry of ${\Bbb C}P^2\times V$, whe

H. Mouri, M. Takaoka, A. Hori, Y. Kawashima

Kolmogorov's theory for turbulence in 1941 is based on a hypothesis that small-scale statistics are uniquely determined by the kinematic viscosity and the mean rate of energy dissipation. Landau remarked that the local rate of energy dissipation should fluctuate in space over large scales and hence should affect small-scale statistics. Experimentally, we

M. Brack, M. Ögren, Y. Yu, S. M. Reimann

We develop a uniform semiclassical trace formula for the density of states of a three-dimensional isotropic harmonic oscillator (HO), perturbed by a term $\propto r^4$. This term breaks the U(3) symmetry of the HO, resulting in a spherical system with SO(3) symmetry. We first treat the anharmonic term in semiclassical perturbation theory by integration of th

Takeo Moroi, Yasuhiro Shimizu, Akira Yotsuyanagi

It has been known that, in the focus point scenario of supersymmetry, the thermal relic of the lightest superparticle (LSP) is known to be a good candidate of the cold dark matter. Assuming that the LSP in the focus-point scenario be the cold dark matter, we address a question how and how well the relic density of the LSP can be determined once the superpart

Thorsten Naab, Jeremiah P. Ostriker

A simple model for the evolution of disc galaxies is presented. We adopt three numbers from observations of the Milky Way disc, the local surface mass density, the stellar scale length (of the assumedly exponential disc) and the amplitude of the (assumedly flat) rotation curve, and physically, the (local) dynamical Kennicutt star formation prescription, stan

E. B. Sonin

According to Faure and Buzdin [Phys. Rev. Lett. 94, 187202 (2005)], in a superconducting ferromagnet a domain structure with a period small compared with the London penetration depth can arise. They claim that this contradicts to the conclusion of Sonin [Phys. Rev. B, 66, 100504 (2002)] that ferromagnetic domain structure in the Meissner state of a supercond

J. Carbonell, V. A. Karmanov

Bethe-Salpeter (BS) equation in Minkowski space for scalar particles is solved for a kernel given by a sum of ladder and cross-ladder exchanges. The solution of corresponding Light-Front (LF) equation, where we add the time-ordered stretched boxes, is also obtained. Cross-ladder contributions are found to be very large and attractive, whereas the influence o

V. A. Karmanov, J. Carbonell

We develop a new method of solving Bethe-Salpeter (BS) equation in Minkowski space. It is based on projecting the BS equation on the light-front (LF) plane and on the Nakanishi integral representation of the BS amplitude. This method is valid for any kernel given by the irreducible Feynman graphs. For massless ladder exchange, our approach reproduces analyti

Alessandro Conflitti

We solve some recurrences given by E. Munarini and N. Zagaglia Salvi proving explicit closed formulas for Whitney numbers of the distributive lattices of order ideals of the fence poset and crown poset. Moreover, we get explicit closed formulas for Whitney numbers of lattices of order ideals of fences with higher asymmetric peaks.