March 2004 arXiv papers — page 10
Showing 901–1,000 of 3,458 papers
Dragomir Neshev, Andrey A. Sukhorukov, Brendan Hanna, Wieslaw Krolikowski
We demonstrate the first fully controlled generation of immobile and slow spatial gap solitons in nonlinear periodic systems with band-gap spectra, and reveal the key features of gap solitons which distinguish them from conventional counterparts, including a dynamical transformation of gap solitons due to nonlinear inter-band coupling. We also predict theore
A. D. Elmendorf, M. A. Mandell
We give a new construction of the algebraic $K$-theory of small permutative categories that preserves multiplicative structure, and therefore allows us to give a unified treatment of rings, modules, and algebras in both the input and output. This requires us to define multiplicative structure on the category of small permutative categories. The framework we
Uniqueness and weak stability for multi-dimensional transport equations with one-sided Lipschitz coefficient
math.APFrancois James, Simona Mancini, Francois Bouchut
The Cauchy problem for a multidimensional linear transport equation with discontinuous coefficient is investigated. Provided the coefficient satisfies a one-sided Lipschitz condition, existence, uniqueness and weak stability of solutions are obtained for either the conservative backward problem or the advective forward problem by duality. Specific uniqueness
Cristina M. Ballantine, Sharon M. Frechette, John B. Little
We consider the matrix ${\frak Z}_P=Z_P+Z_P^t$, where the entries of $Z_P$ are the values of the zeta function of the finite poset $P$. We give a combinatorial interpretation of the determinant of ${\frak Z}_P$ and establish a recursive formula for this determinant in the case in which $P$ is a boolean algebra.
Christel Rotthaus, Liana M. Sega
Let $A=\oplus_{i\in \nn}A_i$ be an excellent homogeneous Noetherian graded ring and let $M=\oplus_{n\in \zz}M_n$ be a finitely generated graded $A$-module. We consider $M$ as a module over $A_0$ and show that the $(S_k)$-loci of $M$ are open in $\Spec(A_0)$. In particular, the Cohen-Macaulay locus $U^0_{CM}=\{\p\in \Spec(A_0) \mid M_\p {is Cohen-Macaulay}\}$
Stephen Semmes
These notes deal with algebras equipped with an involution and related matters.
Grigori Zhitomirski
Prof. Boris I. Plotkin [arXiv:math.GM/0210194, arXiv:math.GM/0204245] drew attention to the question when an equivalence between two categories is isomorphic as a functor to an isomorphism between them. It turns out that it is quite important for universal algebraical geometry and concerns mainly the categories $Θ\sp 0 (X) $ of free universal algebras of som
Christophe Soule
Arithmetic groups are groups of matrices with integral entries. We shall first discuss their origin in number theory (Gauss, Minkowski) and their role in the "reduction theory of quadratic forms". Then we shall describe these groups by generators and relations. The next topic will be: are all subgroups of finite index given by congruence conditions?
Saidi Mohamed
Let $R$ be a complete discrete valuation ring with residue characteristic $p>0$. In this note we give an example of a Galois cover $f:Y\to X$ between flat and normal formal $R$-schemes of finite type which is étale above the generic fibre of $X$ such that the special fibre of $Y$ is reduced and such that $f$ doesn't have the structure of a torsor under a
John Murray
Let G be a finite group, and let Omega:={t\in G\mid t^2=1}. Then Omega is a G-set under conjugation. Let k be an algebraically closed field of characteristic 2. It is shown that each projective indecomposable summand of the G-permutation module kOmega is irreducible and self-dual, whence it belongs to a real 2-block of defect zero. This, together with the fa
Martin Arkowitz, Jeffrey Strom
We study a generalization of the Svarc genus of a fiber map. For an arbitrary collection E of spaces and a map f:X-->Y, we define a numerical invariant, the E-sectional category of f, in terms of open covers of Y. We obtain several basic features of E-sectional category, including those dealing with homotopy domination and homotopy pushouts. We then give thr
Mohamed El Machkouri, Lahcen Ouchti
We give optimal convergence rates in the central limit theorem for a large class of martingale difference sequences with bounded third moments. The rates depend on the behaviour of the conditional variances and for stationary sequences the rate $n^{-1/2}\log n$ is reached. We give interesting examples of martingales with unbounded increments which belong to
Roman Dwilewicz, Joel Merker
Let M be a compact, connected, C^2-smooth and globally minimal hypersurface M in P_2(C) which divides the projective space into two connected parts U^{+} and U^{-}. We prove that there exists a side, U^- or U^+, such that every continuous CR function on M extends holomorphically to this side. Our proof of this theorem is a simplification of a result original
M. Boratynski
The aim of this note is to prove the algebraic geometry analogue of the Invariant tubular neighborhood theorem which concerns the actions of compact Lie groups on smooth manifolds.
S-P Kobayashi, M Kilian, W Rossman, N Schmitt
We show the existence of several new families of non-compact constant mean curvature surfaces: (i) singly-punctured surfaces of arbitrary genus $g \geq 1$, (ii) doubly-punctured tori, and (iii) doubly periodic surfaces with Delaunay ends.
Generalized $C^1$ quadratic B-splines generated by Merrien subdivision algorithm and some applications
math.NAPaul Sablonniere
A new global basis of B-splines is defined in the space of generalized quadratic splines (GQS) generated by Merrien subdivision algorithm. Then, refinement equations for these B-splines and the associated corner-cutting algorithm are given. Afterwards, several applications are presented. First a global construction of monotonic and/or convex generalized spli
Valery Alexeev, Michel Brion
We prove that any affine, resp. polarized projective, spherical variety admits a flat degeneration to an affine, resp. polarized projective, toric variety. Motivated by Mirror Symmetry, we give conditions for the limit toric variety to be a Gorenstein Fano, and provide many examples. We also provide an explanation for the limits as boundary points of the mod
Gianni Ciolli
In the present paper the small Quantum Cohomology ring of some Fano threefolds which are obtained as one- or two-curve blow-ups from $P^3$ or the quadric $Q^3$ is explicitely computed. Because of systematic usage of the associativity property of quantum product only a very small and enumerative subset of Gromov-Witten invariants is needed. Then, for these th
Luc Miller
This article concerns the exact controllability of unitary groups on Hilbert spaces with unbounded control operator. It provides a necessary and sufficient condition not involving time which blends a resolvent estimate and an observability inequality. By the transmutation of controls in some time L for the corresponding second order conservative system, it i
Thierry Zell
Let $A\sub \R^{n+r}$ be a set definable in an o-minimal expansion $§$ of the real field, $A' \sub \R^r$ be its projection, and assume that the non-empty fibers $A_a \sub \R^n$ are compact for all $a \in A'$ and uniformly bounded, {\em i.e.} all fibers are contained in a ball of fixed radius $B(0,R).$ If $L$ is the Hausdorff limit of a sequence of fib
Harald Grosse, Raimar Wulkenhaar
We present the main ideas and techniques of the proof that the duality-covariant four-dimensional noncommutative ϕ^4-model is renormalisable to all orders. This includes the reformulation as a dynamical matrix model, the solution of the free theory by orthogonal polynomials as well as the renormalisation by flow equations involving power-counting theorems fo
Felix Lev
Systems of free particles in a quantum theory based on a Galois field (GFQT) are discussed in detail. In this approach infinities cannot exist, the cosmological constant problem does not arise and one irreducible representation of the symmetry algebra necessarily describes a particle and its antiparticle simultaneously. As a consequence, well known results o
Emanuel Diaconescu, Daniel S. Freed, Gregory Moore
We give a precise formulation of the M-theory 3-form potential C in a fashion applicable to topologically nontrivial situations. In our model the 3-form is related to the Chern-Simons form of an E8 gauge field. This leads to a precise version of the Chern-Simons interaction of 11-dimensional supergravity on manifolds with and without boundary. As an applicat
M. Reuter, H. Weyer
A new framework for exploiting information about the renormalization group (RG) behavior of gravity in a dynamical context is discussed. The Einstein-Hilbert action is RG-improved by replacing Newton's constant and the cosmological constant by scalar functions in the corresponding Lagrangian density. The position dependence of $G$ and $Λ$ is governed by
Zhong Chao Wu
In the $n-$dimensional Freund-Rubin model with an antisymmetric tensor field of rank $s-1$, the dimension of the external spacetime we live in must be $min(s, n-s)$. This result is a generalization of the previous result in the $d=11$ supergravity case, where $s = 4$.
John Ellis
The seesaw model of neutrinos might explain the size, age, flatness and near-homogeneity of the Universe via sneutrino inflation, as well as explaining the origin of matter via leptogenesis. The sneutrino inflation hypothesis makes specific, testable predictions for cosmic microwave background observables, which are compatible with the first release of data
S. M. Bilenky
The neutrinoless double $β$-decay is reviewed. Model independent evidence in favor of neutrino masses and mixing is briefly summarized. The data of the recent experiments on the search for $0νββ$-decay are presented and some future experiments are discussed. The possible values of the effective Majorana mass, which can be predicted on the basis of the neutri
A. Zhang, Y. -R. Liu, P. -Z. Huang, W. -Z. Deng
If Jaffe and Wilczek's diquark picture for $Θ_5$ pentaquark is correct, there should also exist a $SU_F$(3) pentaquark octet and singlet with no orbital excitation between the diquark pair, hence $J^P={1/2}^-$. These states are lighter than the $Θ_5$ anti-decuplet and lie close to the orbitally excited (L=1) three-quark states in the conventional quark m
B. Aubert, BABAR Collaboration
We describe a measurement of the direct CP asymmetry between inclusive b -> s gamma and bbar -> sbar gamma decays. This asymmetry is expected to be less than 0.01 in the Standard Model, but could be enhanced up to about 0.10 by new physics contributions. We use a sample of 89 million BB pairs recorded with the BaBar detector at PEP-II, from which we reconstr
Hernando Quevedo, Ruben D. Zarate
We show that the analysis presented in a recent comment by Coll and Ferrando \cite{comment} (qr-qc/0312058) is based on the erroneous assumption that the chemical potential and fractional concentration of a {\it mixture} of perfect fluids are unknown variables.
Wojciech Skut, Stefan Ulrich, Kathrine Hammervold
We present a flexible rule compiler developed for a text-to-speech (TTS) system. The compiler converts a set of rules into a finite-state transducer (FST). The input and output of the FST are subject to parameterization, so that the system can be applied to strings and sequences of feature-structures. The resulting transducer is guaranteed to realize a funct
Shane Legg, Marcus Hutter, Akshat Kumar
In evolutionary algorithms a critical parameter that must be tuned is that of selection pressure. If it is set too low then the rate of convergence towards the optimum is likely to be slow. Alternatively if the selection pressure is set too high the system is likely to become stuck in a local optimum due to a loss of diversity in the population. The recent F
Wang Liang, Guo Yi-Ping, Fang Ming
Domain Resource Integrated System (DRIS) is introduced in this paper. DRIS is a hierarchical distributed Internet information retrieval system. This system will solve some bottleneck problems such as long update interval, poor coverage in current web search system. DRIS will build the information retrieval infrastructure of Internet, but not a commercial sea
Wang Liang, Guo Yi-Ping, Fang Ming
Search engine is main access to the largest information source in this world, Internet. Now Internet is changing every aspect of our life. Information retrieval service may be its most important services. But for common user, internet search service is still far from our expectation, too many unrelated search results, old information, etc. To solve these pro
G. F. Reiter, P. M. Platzman
Neutron Compton Scattering measurements in a variety of materials have shown a relative deficit in the total signal from hydrogen compared to deuterium and heavier ions. We show here that a breakdown in the Born-Oppenheimer approximation in the final states of the scattering process leads to such a deficit, and may be responsible for the effect.
Dong Yu, Congjun Wang, Brian L. Wehrenberg, Philippe Guyot-Sionnest
The temperature and electrical field dependent conductivity of n-type CdSe nanocrystal thin films is investigated. In the low electrical field regime, the conductivity follows G ~ exp(-(T*/T)^0.5) in the temperature range 10K<T<120K. At high electrical field, the conductivity is strongly field dependent. At 4K, the conductance increases by eight orders of ma
Yoel Calev, Hezy Cohen, Gianaurelio Cuniberti, Abraham Nitzan
A tight binding model for scanning tunneling microscopy images of a molecule adsorbed on a metal surface is described. The model is similar in spirit to that used to analyze conduction along molecular wires connecting two metal leads and makes it possible to relate these two measurements and the information that may be gleaned from the corresponding results.
C. W. Schneider, G. Hammerl, G. Logvenov, T. Kopp
The current-voltage characteristics of Superconducting Quantum Interference Devices (SQUIDs) are known to modulate as a function of applied magnetic field with a period of one flux quantum $Φ_0=h$/2e. Here we report on the fabrication and properties of SQUIDs modulating with a period of $1/2\timesΦ_0$. The characteristics of these bicrystal SQUIDs are consis
Quantum fluctuations and glassy behavior of electrons near metal-insulator transitions
cond-mat.str-elV. Dobrosavljevic
Glassy behavior is a generic feature of electrons close to disorder-driven metal-insulator transitions. Deep in the insulating phase, electrons are tightly bound to impurities, and thus classical models for electron glasses have long been used. As the metallic phase is approached, quantum fluctuations become more important, as they control the electronic mob
Using synchronization to improve earthquake forecasting in a cellular automaton model
cond-mat.dis-nnÁlvaro González, Miguel Vázquez-Prada, Javier B. Gómez, Amalio F. Pacheco
A new forecasting strategy for stochastic systems is introduced. It is inspired by the concept of anticipated synchronization between pairs of chaotic oscillators, recently developed in the area of Dynamical Systems, and by the earthquake forecasting algorithms in which different pattern recognition functions are used for identifying seismic premonitory phen
S. Sivasubramanian, A. Widom, Y. N. Srivastava
Molecular quantum electrodynamics leads to photon frequency shifts and thus to changes in condensed matter free energies often called the Casimir effect. Strong quantum electrodynamic coupling between radiation and molecular motions can lead to an instability beyond which one or more photon oscillators undergo a displacement phase transition. The phase bound
B. H. Lavenda
PAE cannot be made a basis for either a generalized statistical mechanics or a generalized information theory. Either statistical independence must be waived, or the expression of the averaged conditional probability as the difference between the marginal and joint entropies must be relinquished. The same inequality, relating the PAE to the Rényi entropy, wh
Field dependence of the zero energy density of states around vortices in an anisotropic gap superconductor
cond-mat.supr-conN. Nakai, P. Miranović, M. Ichioka, K. Machida
It is shown theoretically that the Sommerfeld coefficient $γ(B)$ in the mixed state contains useful information on the gap topology in a superconductor. We accurately evaluate $γ(B)$ against magnetic induction $B$ by using microscopic quasi-classical theory. The linear portion in {$γ(\propto B)$} relative to $B_{\rm c2}$ and its slope in low field faithfully
Reversible Diffusion-Limited Reactions: "Chemical Equilibrium" State and the Law of Mass Action Revisited
cond-mat.stat-mechR. Voituriez, M. Moreau, G. Oshanin
The validity of two fundamental concepts of classical chemical kinetics - the notion of "Chemical Equilibrium" and the "Law of Mass Action" - are re-examined for reversible \textit{diffusion-limited} reactions (DLR), as exemplified here by association/dissociation $A+A \rightleftharpoons B$ reactions. We consider a general model of long-range
Sylvain Capponi, Congjun Wu, Shou-Cheng Zhang
Strongly interacting systems have been conjectured to spontaneously develop current carrying ground states under certain conditions. We conclusively demonstrate the existence of a commensurate staggered interlayer current phase in a bi-layer model by using the recently discovered quantum Monte-Carlo algorithm without the sign problem. A pseudospin SU(2) alge
Hanbury-Brown Twiss correlations to probe the population statistics of GHz photons emitted by conductors
cond-mat.mes-hallJulien Gabelli, Laure-Helene Reydellet, Gwendal Feve, Jean-Marc Berroir
We present the first study of the statistics of GHz photons in quantum circuits, using Hanbury-Brown and Twiss correlations. The superpoissonian and poissonian photon statistics of thermal and coherent sources respectively made of a resistor and a radiofrequency generator are measured down to the quantum regime at milliKelvin temperatures. As photon correlat
The microcanonical entropy is multiply differentiable. No dinosaurs in microcanonical gravitation: No special "microcanonical phase transitions"
cond-mat.stat-mechD. H. E. Gross
The microcanonical entropy $S=\ln[W(E)]$ is the {\em geometrical measure} of the microscopic redundancy or ignorance about the N-body system. {\em Even for astronomical large systems} is the microcanonical entropy everywhere {\em single valued and multiply differentiable}. Also the microcanonical temperature is at all energies single valued and differentiabl
L. Spanu, A. Parola
Lattice stability in a model of antiferromagnetic ring coupled to adiabatic phonons is investigated for different values of the spin and numbers of magnetic sites. The magneto-elastic transition is shown to be heavily affected by the spin value, displaying a qualitative difference in the nature of the instability for spin one-half. Among the different synthe
D. Bolle', R. Heylen
For the retrieval dynamics of sparsely coded attractor associative memory models with synaptic noise the inclusion of a macroscopic time-dependent threshold is studied. It is shown that if the threshold is chosen appropriately as a function of the cross-talk noise and of the activity of the memorized patterns, adapting itself automatically in the course of t
V. Podzorov, E. Menard, A. Borissov, V. Kiryukhin
The novel technique based on air-gap transistor stamps enabled realization of the intrinsic (not dominated by static disorder) transport of the electric-field-induced charge carriers on the surface of rubrene crystals over a wide temperature range. The signatures of the intrinsic transport are the anisotropy of the carrier mobility, mu, and the growth of mu
Comment on "Memory Effects in an Interacting Magnetic Nanoparticle System" by Sun et. al, prl, 91, 167206 (2003)
cond-mat.mtrl-sciS. Chakravarty, A. Frydman, M. Bandyopadhyay, S. Dattagupta
In this Comment we report a phenomenon identical to that observed in ({Y. Sun, M. B. Salamon, K. Garnier and R. S. Averback, Phys. Rev. Lett. 91, 167206 (2003)}) for systems of NiFe{$_2$}O{$_4$} particles (mean size $\approx$ 3nm) embedded in a SiO{$_2$} matrix with two different interparticle spacings 4 nm (1) and 15 nm (2), which controls the strength of t
R. S. Perry, Y. Maeno
We describe a simple procedure for optimising the growth condition for high quality single crystals of the strontium ruthenate perovskites using an image furnace. The procedure involves carefully measuring the mass lost during crystal growth in order to predict the optimal initial atomic ratio. Using this approach we have succeeded in growing crystals of Sr3
Jun-Jun Liang, J. -Q. Liang, W. -M. Liu
In this paper we study the superfluid-Mott-insulator phase transition of ultracold dilute gas of bosonic atoms in an optical lattice by means of Green function method and Bogliubov transformation as well. The superfluid- Mott-insulator phase transition condition is determined by the energy-band structure with an obvious interpretation of the transition mecha
Z. -D. Chen, J. -Q. Liang, S. -Q. Shen, W. -F. Xie
In terms of exact solutions of the time-dependent Schrodinger equation for an effective giant spin modeled from a coupled two-mode Bose-Einstein condensate (BEC) with adiabatic and cyclic time-varying Raman coupling between two hyperfine states of the BEC, we obtain analytic time-evolution formulas of the population imbalance and relative phase between two c
Huijie Yang, Fangcui Zhao, Longyu Qi, Beilai Hu
The spacing of nearest levels of the spectrum of a complex network can be regarded as a time series. Joint use of Multi-fractal Detrended Fluctuation Approach (MF-DFA) and Diffusion Entropy (DE) is employed to extract characteristics from this time series. For the WS (Watts and Strogatz) small-world model, there exist a critical point at rewiring probability
J. Saint Martin, A. Bournel, P. Dollfus
The scattering effects are studied in nanometer-scaled double-gate MOSFET, using Monte Carlo simulation. The non-equilibrium transport in the channel is analyzed with the help of the spectroscopy of the number of scatterings experienced by electrons. We show that the number of ballistic electrons at the drain end, even in terms of flux, is not the only relev
V. Garcia-Morales, J. Cervera, J. Pellicer
It is well known that the Poisson-Boltzmann (PB) equation yields the exact counterion density around charged objects in the weak coupling limit. In this paper we generalize the PB approach to account for coupling of arbitrary strength by making use of Tsallis q-exponential distributions. Both the weak coupling and the strong coupling limits are reproduced. F
The Red Giant Branch in the Near-Infrared Colour-Magnitude Diagrams. I: The calibration of photometric indices
astro-phE. Valenti, F. R. Ferraro, L. Origlia
We present new high-quality near-infrared photometry of 10 Galactic Globular Clusters spanning a wide metallicity range (-2.12<[Fe/H]<-0.49): five clusters belong to the Halo (namely, NGC288, NGC362, NGC6752, M15 and M30) and five (namely, NGC6342, NGC6380, NGC6440, NGC6441 and NGC6624) to the Bulge. By combining J, H and K observations with optical data, we
Gary Ferland
The spectrum emitted by the Broad Emission Line Regions of Active Galactic Nuclei can measure the luminosity of the central object and the chemical composition of the interstellar medium in a very young galaxy, and so constrain the expansion of the universe and the first stages of the evolution of massive galaxies. Here I review some recent developments in o
J. M. Diego, P. Vielva, E. Martinez-Gonalez, J. Silk
We revisit the possibility that an excess in the CMB power spectrum at small angular scales (CBI, ACBAR) can be due to galaxy clusters (or compact sources in general). We perform a Gaussian analysis of ACBAR-like simulated data based on wavelets. We show how models with a significant excess should show a clear non-Gaussian signal in the wavelet space. In par
Ching-Wa Yip, Andrew Connolly, Daniel Vanden Berk, Zhaoming Ma
We construct eigenspectra from the DR1 quasars in the SDSS using the Karhunen-Loève (KL) transform (or Principal Component Analysis, PCA) in different redshift and luminosity bins. We find that the quasar spectra can be classified, by the first two eigenspectra, into a continuous sequence in the variation of the spectral slope. We also find a dependence on r
Alberto D. Bolatto, James Di Francesco, Chris J. Willott
We report the non-detection of the [CII] 157.74 um transition in the z=6.42 quasar SDSS J1148+5251 after 37.5 hours of integration with the James Clerk Maxwell Telescope. This transition is the main cooling line of the star-forming interstellar medium, and usually the brightest FIR line in galaxies. Our observed RMS of 1.3 mK in the Ta* scale translates to L
Nolan R. Walborn, Nidia I. Morrell, Ian D. Howarth, Paul A. Crowther
From a survey of the 3400 A region in the earliest O-type spectra, we have found that two of the four O2 giants observed in the LMC have the OIV lines there stronger than the NIV, while the other two have the opposite. A SMC counterpart also has the NIV stronger than OIV. Inspection of the blue spectra of these stars shows that the former pair have weaker N
C. P. Haines, A. Mercurio, P. Merluzzi, F. La Barbera
We examine the environmental effects on the photometric properties of galaxies for the rich galaxy cluster ABCG 209 at z=0.209. We use archive CFHT optical imaging of a 42'x28' field centred on the cluster to produce a galaxy sample complete to B=25.0 and R=24.5. Both the composite and red sequence galaxy luminosity functions are found to be dependen
Reduction of chemical networks. II. Analysis of the fractional ionisation in protoplanetary discs
astro-phD. Semenov, D. Wiebe, Th. Henning
(abridged) We analyse the evolution of the fractional ionisation in a steady-state protoplanetary disc with a vertical temperature gradient and with gas-grain chemistry including surface reactions. The ionisation due to stellar X-rays, stellar and interstellar UV radiation, cosmic rays and radionuclide decay is taken into account. Using our reduction schemes
Martin Elvis
A combination of microchannel plate optics and a 32x32 pixel microcalorimeter would allow the successor to the Rossi XTE to explore new domains of spectroscopic timing in a MIDEX class mission. With ~10 times the area and ~100 times the spectral resolution of the PCA (and 10 times that of silicon detectors) such a mission would be able to explore redshifts a
D. J. Champion, D. R. Lorimer, M. A. McLaughlin, J. M. Cordes
We report the discovery of a new binary pulsar, PSR J1829+2456, found during a mid-latitude drift-scan survey with the Arecibo telescope. Our initial timing observations show the 41-ms pulsar to be in a 28-hr, slightly eccentric, binary orbit. The advance of periastron, omegadot = 0.28 +/- 0.01 deg/yr is derived from our timing observations spanning 200 days
M. Gilfanov
We review recent results on populations of compact X-ray sources in normal galaxies. The luminosity distributions of low and high mass X-ray binaries in nearby galaxies appear to be described by the respective ``universal'' luminosity functions, whose shapes do not vary significantly from galaxy to galaxy and the normalizations are proportional to th
Carlos Valotto, Riccardo Giovanelli
Observations show that the slope of the inner part of the H$α$/[NII] rotation curves of disk galaxies is depressed by extinction: at fixed luminosity, the observed slope is in fact seen to depend on the disk inclination to the line of sight. Using a simple extinction model, we are able to reproduce well the observed trends. The model assumes an exponential d
M. Bejger, P. Haensel
The upper bound on the value of the surface gravity, g_s, for neutron stars with equations of state respecting v_sound <= c, is derived. This bound is inversely proportional to the maximum allowable mass M_max, and it reads g_s <= 1.411 x 10^15 (M_sun/M_max) cm/s^2. It implies an absolute upper bound 7.4 x 10^14 cm/s^2 if one uses the 2sigma lower bound on t
J. S. Bloom
From both photometric and broadband spectral monitoring of gamma-ray burst (GRB) lightcurve ``bumps,'' particularly in GRB 011121, a strong case grew for a supernova (SN) origin. The GRB-SN connection was finally solidified beyond a reasonable doubt with the discovery that the bump in GRB 030329 was spectroscopically similar to a bright Type Ic SN. I
Yu. A. Fadeyev, D. Gillet
We considered the structure of steady-state plane-parallel radiative shock waves propagating through the partially ionized hydrogen gas of temperature T_1 = 3000K and density 1e-12 gm/cm^3 <= ρ_1 <= 1e-9 gm/cm^3. The upstream Mach numbers range within 6 <= M_1 <= 14. In frequency intervals of hydrogen lines the radiation field was treated using the transfer
Chris Done, Marek Gierlinski
We systematically analyzed about a terabyte of data from Galactic binary systems to characterize how these spectra change as a function of mass accretion rate. With this volume of data we are able to identify the differences in behaviour of black holes and neutron stars, implying that black holes really do have an event horizon. The spectral evolution seen a
Helene Courtois, Georges Paturel, Thierry Sousbie, Francesco Sylos Labini
In order to investigate the properties of large-scale structures of galaxies in the universe, we present an analysis of their spatial distribution at z$<$0.033. We used the LEDA extragalactic database containing over 1 million of galaxies covering the all-sky and the SDSS data included in the public release DR1, yielding to a sample of around 134,000 galaxie
Antonio C. da Silva
Observations with the SZ effect constitute a powerful new tool for investigating clusters and constraining cosmological parameters. Of particular interest is to investigate how the SZ signal correlates with other cluster properties, such as the mass, temperature and X-ray luminosities. In this presentation we quantify these relations for clusters found in hy
An extended scheme for fitting X-ray data with accretion disk spectra in the strong gravity regime
astro-phM. Dovciak, V. Karas, T. Yaqoob
Accreting black holes are believed to emit X-rays which then mediate information about strong gravity in the vicinity of the emission region. We report on a set of new routines for the Xspec package for analysing X-ray spectra of black-hole accretion disks. The new computational tool significantly extends the capabilities of the currently available fitting p
K. Koike, H. Chihara, C. Koike, M. Nakagawa
Possible forsterite nanoparticle model of the Extended Red Emission(ERE) is proposed on the basis of photo-luminescence of forsterite after gamma-ray and neutron irradiation. Forsterite exhibits interesting thermoluminescence spectrum similar to ERE of Red Rectangle after irradiation in low temperature. It is shown that the forsterite after thermoluminescenc
Jonathan E. Grindlay
The Energetic X-ray Timing Survey Telescope (EXIST) mission concept is under study as the Black Hole Finder Probe (BHFP), one of the three Einstein Probe missions in the Beyond Einstein Program in the current NASA Strategic Plan. EXIST would conduct an all-sky imaging hard X-ray ($\sim$10-600 keV) survey with unprecedented sensitivity: about 5 $\times 10^{-1
Resolving the Host Galaxy of the Nearby QSO I Zw 1 with Sub-Arcsecond Multi-Transition Molecular Line Observations
astro-phJ. G. Staguhn, E. Schinnerer, A. Eckart, J. Scharwächter
We present the first sub-kpc 0.7" (~ 850 pc) resolution 12CO(1-0) molecular line observations of the ISM in the host galaxy of the QSO I Zw 1. The observations were obtained with the BIMA mm-interferometer in its compact A configuration. The BIMA data are complemented by new observations of the 12CO(2-1) and 13CO(1-0) line with IRAM Plateau de Bure mm-in
The evolution of the luminosity functions in the FORS Deep Field from low to high redshift: I. The blue bands
astro-phA. Gabasch, R. Bender, S. Seitz, U. Hopp
We use the very deep and homogeneous I-band selected dataset of the FORS Deep Field (FDF) to trace the evolution of the luminosity function over the redshift range 0.5 < z < 5.0. We show that the FDF I-band selection down to I(AB)=26.8 misses of the order of 10 % of the galaxies that would be detected in a K-band selected survey with magnitude limit K(AB)=26
E787 Collaboration
We report the results of a search for the decay $K^+ \to π^+ ν\bar ν$ in the kinematic region with $π^+$ momentum $140 < P < 195$ MeV/c using the data collected by the E787 experiment at BNL. No events were observed. When combined with our previous search in this region, one candidate event with an expected background of $1.22 \pm 0.24$ events results in a 9
C. Vastel, T. G. Phillips, H. Yoshida
The 692 GHz para ground-state line of D2H+ has been detected at the Caltech Submillimeter Observatory towards the pre-stellar core 16293E. The derived D2H+ abundance is comparable to that of H2D+, as determined by observations of the 372 GHz line of ortho-H2D+. This is an observational verification of recent theoretical predictions (Roberts, Herbst & Millar
I. Ferreras, J. Silk, A. Boehm, B. L. Ziegler
We combine the latest observations of disk galaxy photometry and rotation curves at moderate redshift from the FORS Deep Field (FDF) with simple models of chemical enrichment. Our method describes the buildup of the stellar component through infall of gas and allows for gas and metal outflows. In this framework, we keep a minimum number of constraints and we
I. Martin, E. Kaneshita, R. J. McQueeney, Z. G. Yu
By applying an unrestricted Hartree-Fock and a Random Phase approximations to a multiband Peierls-Hubbard Hamiltonian, we study the phonon mode structure in models of transition metal oxides in the presence of intrinsic nanoscale inhomogeneities induced by hole doping. We identify low frequency $local$ vibrational modes pinned to the sharp interfaces between
V. V. Braguta, A. I. Onishchenko
We present an analysis of QCD sum rules for pion form factor in next-to-leading order of perturbation theory for the case of axial-vector pion currents. The theoretical predictions for Q^2-dependence of pion form factor are in good agreement with available experimental data. It is shown, that NLO corrections are large in this case and should be taken into ac
V. Bernard, S. Gardner, U. -G. Meißner, C. Zhang
We consider radiative β--decay of the neutron in heavy baryon chiral perturbation theory, with an extension including explicit Δdegrees of freedom. We compute the photon energy spectrum as well as the photon polarization; both observables are dominated by the electron bremsstrahlung contribution. Nucleon-structure effects not encoded in the weak coupling con
L. Rizzuto, R. Passante, F. Persico
We consider the Casimir-Polder interaction between two atoms, one in the ground state and the other in its excited state. The interaction is time-dependent for this system, because of the dynamical self-dressing and the spontaneous decay of the excited atom. We calculate the dynamical Casimir-Polder potential between the two atoms using an effective Hamilton
Neil Barnaby, James M. Cline
When p-dimensional branes annihilate with antibranes in the early universe, as in brane-antibrane inflation, stable (p-2)-dimensional branes can appear in the final state. We reexamine the possibility that one of these (p-2)-branes could be our universe. In the low energy effective theory, the final state branes are cosmic string defects of the complex tachy
N. P. Proukakis, N. G. Parker, C. F. Barenghi, C. S. Adams
A dark soliton oscillating in an elongated harmonically-confined atomic Bose-Einstein condensate continuously exchanges energy with the sound field. Periodic optical `paddles' are employed to controllably enhance the sound density and transfer energy to the soliton, analogous to parametric driving. In the absence of damping, the amplitude of the soliton
Relativistic Quasilinear Diffusion in Axisymmetric Magnetic Geometry for Arbitrary-Frequency Electromagnetic Fluctuations
physics.space-phAlain J. Brizard, Anthony A. Chan
A relativistic bounce-averaged quasilinear diffusion equation is derived to describe stochastic particle transport associated with arbitrary-frequency electromagnetic fluctuations in a nonuniform magnetized plasma. Expressions for the elements of a relativistic quasilinear diffusion tensor are calculated explicitly for magnetically-trapped particle distribut
V. K. Magas, L. Roca, E. Oset
We perform calculations for the production of $ϕ$ mesons in nuclei at energies just above threshold and study the $A$ dependence of the cross section. We use results for the $ϕ$ selfenergy in the medium obtained within a chiral unitary approach. We find a strong $A$ dependence which is tied to the distortion of the incident proton and to the absorption of th
L. Clavelli, G. Karatheodoris
We propose a model for gamma ray bursts in which a star subject to a high level of fermion degeneracy undergoes a phase transition to a supersymmetric state. The burst is initiated by the transition of fermion pairs to sfermion pairs which, uninhibited by the Pauli exclusion principle, can drop to the ground state of minimum momentum through photon emission.
Reconsidering the quantization of electrodynamics with boundary conditions and some measurable consequences
hep-thM. Bordag
We show that the commonly known conductor boundary conditions $E_{||}=B_\perp=0$ can be realized in two ways which we call 'thick' and 'thin' conductor. The 'thick' conductor is the commonly known approach and includes a Neumann condition on the normal component $E_\perp$ of the electric field whereas for a 'thin' conductor $E
Geza Odor
The phase transitions of the recently introduced 2A -> 3A, 4A -> 0 reaction-diffusion model (G.Odor, PRE 69 036112 (2004)) are explored in two dimensions. This model exhibits site occupation restriction and explicit diffusion of isolated particles. A reentrant phase diagram in the diffusion - creation rate space is confirmed in agreement with cluster mean-fi
Gianguido Dall'Agata
We propose a general spinor Ansatz to find supersymmetric configurations preserving 4-dimensional Poincare' invariance in the context of type IIB supergravity in the presence of general fluxes. We show how this removes the imaginary-selfduality (ISD) constraint on the 3-form flux and present a simple example with nonvanishing (0,3) flux. To characterize
Bruno Carneiro da Cunha
We show that the DBI action for the singlet sector of the tachyon in two-dimensional string theory has a SL(2,R) symmetry, a real-time counterpart of the ground ring. The action can be rewritten as that of point particles moving in a de Sitter space, whose coordinates are given by the value of the eigenvalue and time. The symmetry then manifests as the isome
B. Bunk, M. Della Morte, K. Jansen, F. Knechtli
We address the locality problem arising in simulations, which take the square root of the staggered fermion determinant as a Boltzmann weight to reduce the number of dynamical quark tastes. A definition of such a theory necessitates an underlying local fermion operator with the same determinant and the corresponding Green's functions to establish causali
Unitarization of monodromy representations and constant mean curvature trinoids in 3-dimensional space forms
math.DGN Schmitt, M Kilian, S-P Kobayashi, W Rossman
We present a theorem on the unitarizability of loop group valued monodromy representations and apply this to show the existence of new families of constant mean curvature surfaces homeomorphic to a thrice-punctured sphere in the simply-connected 3-dimensional space forms $\R^3$, $\bbS^3 $ and $\bbH^3$. Additionally, we compute the extended frame for any asso
Petter Brändén
We prove that certain linear operators preserve the Pólya frequency property and real-rootedness, and apply our results to settle some conjectures and open problems in combinatorics proposed by Bóna, Brenti and Reiner-Welker.
Phonons, electronic charge response and electron-phonon interaction in the high-temperature superconductors
cond-mat.supr-conClaus Falter
We investigate in the framework of linear response theory the complete phonon dispersion, phonon induced electronic charge response, electron-phonon interaction and dielectric and infrared properties of the high-temperature superconductors (HTSC's). In particular the experimentally observed strong renormalization of the in-plane oxygen bond-stretching mo