January 2003 arXiv papers — page 17

Amr El-Zant, Isaac Shlosman, Mitch Begelman, Juhan Frank

The masses of supermassive black holes (SBHs) show correlations with bulge properties in disk and elliptical galaxies. We study the formation of galactic structure within flat-core triaxial haloes and show that these correlations can be understood within the framework of a baryonic component modifying the orbital structure in the underlying potential. In par

Steve Croft, Steve Rawlings, Gary J. Hill

The TexOx Cluster (TOC) Survey uses overdensities of radiosources in the NVSS to trace clusters of galaxies. The links between radiosources and rich environments make this a powerful way to find clusters which may potentially be overlooked by other selection techniques. By including constraints from optical surveys, TOC is an extremely efficient way to find

Sebastian Wolf, Deborah L. Padgett, Karl R. Stapelfeldt

We present a model of the circumstellar environment of the so-called ``Butterfly Star'' in Taurus (IRAS 04302+2247). The appearance of this young stellar object is dominated by a large circumstellar disk seen edge-on and the light scattering lobes above the disk. The model is based on multi-wavelength continuum observations: Millimeter maps and high-

P. Hoeflich, C. Gerardy, E. Linder, H. Marion

We give an overview of the current understanding of Type Ia supernovae relevant for their use as cosmological distance indicators. We present the physical basis to understand their homogeneity of the observed light curves and spectra and the observed correlations. This provides a robust method to determine the Hubble constant, 67 +- 8 (2 sigma) km/Mpc/sec, i

B. Glenn Piner, Stephen C. Unwin, Ann E. Wehrle, Alma C. Zook

We have calculated inverse-Compton Doppler factors for 3C 279 using the collection of VLBI data recently published by us, and the collection of multiwavelength spectra recently published by Hartman et al. From the Doppler factor and superluminal apparent speed, we then calculate the Lorentz factor and angle to the line-of-sight of the parsec-scale relativist

M. L. Lister

The study of compact active galactic nuclei (AGN) that possess convex radio spectra (the gigahertz-peaked spectrum radio sources) offers a unique opportunity to probe both the early evolutionary stages of relativistic AGN jets and their immediate nuclear environments. In this article I trace Ken Kellermann's early investigations of these sources, which p

Edison Liang, Kazumi Nishimura, Hui Li, S. Peter Gary

Using a 2-1/2-dimensional particle-in-cell (PIC) code to simulate the relativistic expansion of a magnetized collisionless plasma into a vacuum, we report a new mechanism in which the magnetic energy is efficiently converted into the directed kinetic energy of a small fraction of surface particles. We study this mechanism for both electron-positron and elect

T. V. Borkova, V. A. Marsakov

We found that 10 metal-poor globular clusters are greately distinguished for anomalously small masses on the "destruction rate--mass" plain. As it turned out, these poor clusters, situated 15 kpc farther from the Galactic centre, are somewhat younger than the bulk of the metal-poor globulars, and have anomalously red horizontal branches. All these cl

Simon Vidrih, Andrej Cadez, Mirjam Galicic, Alberto Carraminana

Photometric data of the Crab pulsar, obtained in stroboscopic mode over a period of more than eight years, are presented here. The applied Fourier analysis reveals a faint 60 second modulation of the pulsar's signal, which we interpret as a free precession of the pulsar.

D. R. Lorimer

The observed population of young radio pulsars has grown substantially in recent years due to a combination of large-scale surveys and deep targeted searches. Many of the pulsars are associated with supernova remnants and/or unidentified gamma-ray sources. This review summarises the state of play and looks ahead to likely advances in the near future.

Jason Glenn, Philip R. Jewell, Remy Fourre, Luis Miaja

We have monitored the SiO (v = 1, J = 2 -> 1) maser polarization in 17 variable stars (Miras, OH-IR stars, and supergiants) to investigate the long-term persistence of masers. The 8 epochs of observations span 2.5 years, thereby sampling multiple cycles for these stars with typical periods of ~1 year. The average polarization was 23% with a typical dispersio

S. Ciprini, G. Tosti, C. M. Raiteri, M. Villata

We present the most continuous data base of optical $BVR_{c}I_{c}$ observations ever published on the BL Lacertae object GC 0109+224, collected mainly by the robotic telescope of the Perugia University Observatory in the period November 1994-February 2002. These observations have been complemented by data from the Torino Observatory, collected in the period

Alberto Vecchiato, Mario G. Lattanzi, Beatrice Bucciarelli, Maria Teresa Crosta

The global astrometric observations of a GAIA-like satellite were modeled within the PPN formulation of Post-Newtonian gravitation. An extensive experimental campaign based on realistic end-to-end simulations was conducted to establish the sensitivity of global astrometry to the PPN parameter γ, which measures the amount of space curvature produced by unit r

M. C. Smith, S. Mao, P. R. Wozniak

We describe a unique mass determination for a microlensing event from the second phase of the Optical Gravitational Microlensing Experiment (OGLE-II). The event, sc26_2218, which is very bright (baseline magnitude I=15.10), appears to exhibit both parallax and finite source effects. The parallax effect allows us to determine the projected Einstein radius on

L. Cortese, G. Gavazzi, J. Iglesias-Paramo, A. Boselli

Optical spectroscopy of 93 galaxies, 60 projected in the direction of Abell 1367, 21 onto the Coma cluster and 12 on Virgo, is reported. The targets were selected either because they were detected in previous Hα, UV or r' surveys. The present observations bring to 100% the redshift completeness of Hαselected galaxies in the Coma region and to 75% in Abel

S. S. Holt, E. M. Schlegel, U. Hwang, R. Petre

We present the results of a study of discrete X-ray sources in NGC 6946 using a deep Chandra ACIS observation. Based on the slope of the log N-log S distribution and the general correlation of sources with the spiral arms, we infer that the overall discrete source sample in NGC 6946 is dominated by high mass X-ray binaries, in contrast to the source distribu

D. D. Frederiks, R. L. Aptekar, S. V. Golenetskii, V. N. Il'inskii

For a ten of 125 short GRBs observed by Konus-Wind and the Konus-A the existance of statistically significant flux of hard photons accompanying initial event for a time of tens to hundred seconds after the trigger was revealed. Temporal, spectral, and energetic characteristics of these events are presented. The statistical analysis of the whole burst sample

Davide Lazzati

The properties of the ambient medium in which GRBs go off are an important piece of the puzzle, not only as an issue in itself, but because of their link with the nature of the progenitor. In this review, I describe and critically comment the various experiments proposed to study the burst environment. I discuss emission and absorption features techniques an

T. V. Zaqarashvili

We suggest that the global torsional oscillation of solar coronal loop may be observed by the periodical variation of a spectral line width. The amplitude of the variation must be maximal at the velocity antinodes and minimal at the nodes of the torsional oscillation. Then the spectroscopic observation as a time series at different heights above the active r

Jeremy Darling, Paul Goldsmith, Di Li, Riccardo Giovanelli

We report the results of a search for 6.7 GHz methanol (CH3OH) maser emission in OH megamaser galaxies at 0.11<z<0.27. No detections were made in the 25 objects observed down to rms noise levels of roughly 0.6 mJy in 150 kHz channels. The OH megamaser sample includes OH emission of all observed types: narrow and broad, physically compact and extended, variab

Lam Hui

The flux/transmission power spectrum has become a popular statistical tool in studies of the high redshift ($z > 2$) Lyman-alpha forest. At low redshifts, where the forest has thinned out into a series of well-isolated absorption lines, the motivation for flux statistics is less obvious. Here, we study the relative merits of flux versus line correlations, an

Daniel Kasen, Peter Nugent, Lifan Wang, D. A. Howell

SN 2001el is the first normal Type Ia supernova to show a strong, intrinsic polarization signal. In addition, during the epochs prior to maximum light, the CaII IR triplet absorption is seen distinctly and separately at both normal photospheric velocities and at very high velocities. The high-velocity triplet absorption is highly polarized, with a different

M. Goto, W. Gaessler, Y. Hayano, M. Iye

We present medium-resolution 3 um spectroscopy of the carbon-rich proto-planetary nebula IRAS 22272+5435. Spectroscopy with the Subaru Telescope adaptive optics system revealed a spatial variation of hydrocarbon molecules and dust surrounding the star. The ro-vibrational bands of acetylene (C2H2) and hydrogen cyanide (HCN) at 3.0 um are evident in the centra

D. Pogosyan, J. R. Bond, C. R. Contaldi

Full suite of the present day Cosmic Microwave background (CMB) data, when combined with weak prior information on the Hubble constant and the age of the Universe, or the Large-Scale structure, provides strong indication for a non-zero density of the vacuum-like dark energy in our universe. This result independently supports the conclusions from Supernovae I

Meg Urry

Radio-loud AGN are characterized by relativistic jets originating near the central supermassive black hole and forming large-scale radio sources at parsec to kiloparsec to Megaparsec distances. The jets are energetically significant, in many cases representing the bulk of the energy extracted from the accretion process. Host galaxies are apparently normal lu

Rachel Bean, Olivier Doré

We study the implications on both background and perturbation evolution of introducing a Chaplygin gas component in the universe&#39;s ingredients. We perform likelihood analyses using wide-ranging, SN1a, CMB and large scale structure observations to assess whether such a component could be a genuine alternative to a cosmological constant. We find that curre

G. Dourado Barbosa

We propose an alternative interpretation for the meaning of noncommutativity of the string-inspired field theories and quantum mechanics. Arguments are presented to show that the noncommutativity generated in the stringy context should be assumed to be only between the particle coordinate observables, and not of the spacetime coordinates. Some implications o

Tarek Ibrahim, Pran Nath

We compute supersymmetric QCD and supersymmetric electroweak corrections to the b and t quark masses and to the $τ$ lepton mass in the presence of CP phases valid for all $\tanβ$. The analysis includes one loop diagrams arising from the exchange of gluinos, charginos and neutralinos. We find that the CP effects can change both the magnitude as well as the si

Tomotsugu Goto, Sadanori Okamura, Masafumi Yagi, Ravi K. Sheth

We investigate the evolution of the fractions of late type cluster galaxies as a function of redshift, using one of the largest, most uniform cluster samples available. The sample consists of 514 clusters of galaxies in the range 0.02<z<0.3 from the Sloan Digital Sky Survey Cut & Enhance galaxy cluster catalog. This catalog was created using a single automat

Walter D. Neumann, Jonathan Wahl

While the topological types of {normal} surface singularities with homology sphere link have been classified, forming a rich class, until recently little was known about the possible analytic structures. We proved in [Geom. Topol. 9(2005) 699-755] that many of them can be realized as complete intersection singularities of &#34;splice type&#34;, generalizing

Vasyl P. Lukomsky, Ivan S. Gandzha

The dynamics of a one-degree of freedom oscillator with arbitrary polynomial non-linearity subjected to an external periodic excitation is studied. The sequences (cascades) of harmonic and subharmonic stationary solutions to the equation of motion are obtained by using the harmonic balance approximation adapted for arbitrary truncation numbers, powers of non

S. Khlebnikov

Decoherence associated with super-Hubble modes in de Sitter space may have a dual description, in which it is attributed to interaction of sub-Hubble modes with an ``environment&#39;&#39; residing just inside the observer&#39;s horizon. We present a version of such description, together with some consistency checks, which it is shown to pass.

E. D&#39;Hoker, P. Heslop, P. Howe, A. V. Ryzhov

A systematic construction is presented of 1/4 BPS operators in N=4 superconformal Yang-Mills theory, using either analytic superspace methods or components. In the construction, the operators of the classical theory annihilated by 4 out of 16 supercharges are arranged into two types. The first type consists of those operators that contain 1/4 BPS operators i

P. K. Aravind

A proof of the generalized Kochen-Specker theorem in two dimensions due to Cabello and Nakamura is extended to all higher dimensions. A set of 18 states in four dimensions is used to give closely related proofs of the generalized Kochen-Specker, Kochen-Specker and Bell theorems that shed some light on the relationship between these three theorems.

Yu Zhang

Consider percolation on the triangular lattice. Let $κ(p)$ be the free energy at the zero field. We show that $$|κ&#39;&#39;&#39;(p)| \leq |p-p_c|^{-1/3+o(1)} \mbox{ if } p \neq p_c.$$ Furthermore, we show that there exists a sequence $ε_n\downarrow 0$ such that $$|κ&#39;&#39;&#39;(p_c\pm ε_n)|\geq ε_n^{-1/3+o(1)}.$$ This answers affirmatively a conjecture,

Alessandro Cafarella, Claudio Corianó

According to a rederivation - due to Collins and Qiu - the DGLAP equation can be reinterpreted (in leading order) in a probabilistic way. This form of the equation has been used indirectly to prove the bound $|Δf(x,Q)| < f(x,Q)$ between polarized and unpolarized distributions, or positivity of the helicity distributions, for any $Q$. We reanalize this issue

E. Berti, K. D. Kokkotas

We study scalar, electromagnetic and gravitational perturbations of a Reissner-Nordström-anti-de Sitter (RN-AdS) spacetime, and compute its quasinormal modes (QNM&#39;s). We confirm and extend results previously found for Schwarzschild-anti-de Sitter (S-AdS) black holes. For ``large&#39;&#39; black holes, whose horizon is much larger than the AdS radius, dif

M. P. Fry

An exact representation of the Euclidean fermion determinant in two dimensions for centrally symmetric, finite-ranged Abelian background fields is derived. Input data are the wave function inside the field&#39;s range and the scattering phase shift with their momenta rotated to the positive imaginary axis and fixed at the fermion mass for each partial-wave.

James M. Cline, Hassan Firouzjahi

Unstable D-branes or brane-antibrane systems can decay to lower-dimensional branes. In the effective field theory description, the final state branes are defects in the tachyon field which describes the initial instability. We study the dynamical formation of codimension one defects (kinks) using Sen&#39;s ansatz for the tachyon Lagrangian. It is shown that

B. Ciardi, F. Stoehr, S. D. M. White

We have studied the IGM reionization process in its full cosmological context including structure evolution and a realistic galaxy population. We have used a combination of high-resolution N-body simulations (to describe the dark matter and diffuse gas component), a semi-analytic model of galaxy formation (to track the evolution of the sources of ionizing ra

Guilhem Semerjian, Remi Monasson

An analysis of the average properties of a local search resolution procedure for the satisfaction of random Boolean constraints is presented. Depending on the ratio alpha of constraints per variable, resolution takes a time T_res growing linearly (T_res \sim tau(alpha) N, alpha < alpha_d) or exponentially (T_res \sim exp(N zeta(alpha)), alpha > alpha_d) with

Wolfgang Barthel, Alexander K. Hartmann, Martin Weigt

Stochastic local search algorithms are frequently used to numerically solve hard combinatorial optimization or decision problems. We give numerical and approximate analytical descriptions of the dynamics of such algorithms applied to random satisfiability problems. We find two different dynamical regimes, depending on the number of constraints per variable:

A. J. Drake

We present a new method for differentiating between planetary transits and eclipsing binaries based on the presence of the ellipsoidal light variations. These variations can be used to detect stellar secondaries with masses ~0.2 M_sun orbiting sun-like stars at a photometric accuracy level which has already been achieved in transit surveys. By removing candi

D. Bahns, S. Doplicher, K. Fredenhagen, G. Piacitelli

We discuss a formulation of quantum field theory on quantum space time where the perturbation expansion of the S-matrix is term by term ultraviolet finite. The characteristic feature of our approach is a quantum version of the Wick product at coinciding points: the differences of coordinates q_j - q_k are not set equal to zero, which would violate the commut

G. De Troia, P. A. R. Ade, J. J. Bock, J. R. Bond

The trispectrum of the cosmic microwave background can be used to assess the level of non-Gaussianity on cosmological scales. It probes the fourth order moment, as a function of angular scale, of the probability distribution function of fluctuations and has been shown to be sensitive to primordial non-gaussianity, secondary anisotropies (such as the Ostriker

Joakim Edsjo, Mia Schelke, Piero Ullio, Paolo Gondolo

Neutralinos arise as natural dark matter candidates in many supersymmetric extensions of the Standard Model. We present a novel calculation of the neutralino relic abundance in which we include all so called coannihilation processes between neutralinos, charginos and sfermions, and, at the same time, we apply the state of the art technique to trace the freez

Peter E. Frenkel

We consider fully effective orientation-preserving smooth actions of a given finite group G on smooth, closed, oriented 3-manifolds M. We investigate the relations that necessarily hold between the numbers of fixed points of various non-cyclic subgroups. In Section 2, we show that all such relations are in fact equations mod 2, and we explain how the number

Adi Armoni, Esperanza Lopez, Angel M. Uranga

We observe a relation between closed strings tachyons and one-loop instabilities in non-supersymmetric non-commutative gauge theories. In particular we analyze the spectra of type IIB string theory on C^3/Z_N orbifold singularities and the non-commutative field theory that lives on D3 branes located at the singularity. We find a surprising correspondence bet

G. Sartori, G. Valente

Functions which are equivariant or invariant under the transformations of a compact linear group $G$ acting in an euclidean space $\real^n$, can profitably be studied as functions defined in the orbit space of the group. The orbit space is the union of a finite set of strata, which are semialgebraic manifolds formed by the $G$-orbits with the same orbit-type

Z. Y. Zeng, Baowen Li, F. Claro

We present a unified transport theory of hybrid structures, in which a confined normal state ($N$) sample is sandwiched between two leads each of which can be either a ferromagnet ($F$) or a superconductor ($S$) via tunnel barriers. By introducing a four-dimensional Nambu-spinor space, a general current formula is derived within the Keldysh nonequilibrium Gr

A. D. Rata, A. R. Chezan, T. Hibma, M. W. Haverkort

We have succeeded in growing epitaxial films of rocksalt VOx on MgO(001) substrates. The oxygen content as a function of oxygen flux was determined using 18O2-RBS and the vanadium valence using XAS. The upper and lower stoichiometry limits found are similar to the ones known for bulk material (0.8<x<1.3). From the RHEED oscillation period a large number of v

Seung-Kook Kim, Yong-Wan Kim, Young-Jai Park

We study the constraint structure of the topologically massive theory with one- and two-form fields in the framework of Batalin-Fradkin-Tyutin embedding procedure. Through this analysis we obtain a new type of Wess-Jumino action with novel symmetry, which is originated from the topological coupling term, as well as the Stückelberg action related to the expli

Werner Porod

SPheno is a program that accurately calculates the supersymmetric particle spectrum within a high scale theory, such as minimal supergravity, gauge mediated supersymmetry breaking, anomaly mediated supersymmetry breaking, or string effective field theories. An interface exists for an easy implementation of other models. The program solves the renormalization

Heng Fan

The property of the optimal signal ensembles of entanglement assisted channel capacity is studied. A relationship between entanglement assisted channel capacity and one-shot capacity of unassisted channel is obtained. The data processing inequalities, convexity and additivity of the entanglement assisted channel capacity are reformulated by simple methods.

Nobuyoshi Ohta

We give a model-independent derivation of general intersecting rules for spacelike branes (S-branes) in arbitrary dimensions $d$. This is achieved by directly solving bosonic field equations for supergravity coupled to a dilaton and antisymmetric tensor fields with minimal ansätze. We compare the results with those in eleven-dimensional supergravity and othe

Tudor D. Stanescu, Philip Phillips

Though most fermionic Mott insulators order at low temperatures, ordering is ancillary to their insulating behaviour. Our emphasis here is on disentangling ordering from the intrinsic strongly correlated physics of a doped half-filled band. To this end, we focus on the 2D Hubbard model. Because the charge gap arises from on-site correlations, we implement a

Simon DeDeo, R. R. Caldwell, Paul J. Steinhardt

We consider how quintessence models in which the sound speed differs from the speed of light and varies with time affect the cosmic microwave background and the fluctuation power spectrum. Significant modifications occur on length scales related to the Hubble radius during epochs in which the sound speed is near zero and the quintessence contributes a non-ne

Guifre Vidal

We present a scheme to efficiently simulate, with a classical computer, the dynamics of multipartite quantum systems on which the amount of entanglement (or of correlations in the case of mixed-state dynamics) is conveniently restricted. The evolution of a pure state of n qubits can be simulated by using computational resources that grow linearly in n and ex

Samir Salim, Sebastien Lepine, R. Michael Rich, Michael M. Shara

We report the discovery of LSR0602+3910, an L dwarf of class L1. The object was initially identified by Lepine et al. (2002) as a new high proper motion star lying close to the Galactic plane. Its 2MASS J-K_s=1.43 is consistent with an L dwarf, which we now confirm spectroscopically. In addition, we see a signature of Li I absorption, making LSR0602+3910 a b

Darren Reed, Jeffrey Gardner, Thomas Quinn, Joachim Stadel

We use a high resolution $Λ$CDM numerical simulation to calculate the mass function of dark matter haloes down to the scale of dwarf galaxies, back to a redshift of fifteen, in a 50 $h^{-1}$Mpc volume containing 80 million particles. Our low redshift results allow us to probe low $σ$ density fluctuations significantly beyond the range of previous cosmologica

Idit Zehavi, David H. Weinberg, Zheng Zheng, Andreas A. Berlind

We measure the projected correlation function w_p(r_p) from the Sloan Digital Sky Survey for a flux-limited sample of 118,000 galaxies and for a volume limited subset of 22,000 galaxies with absolute magnitude M_r<-21. Both correlation functions show subtle but systematic departures from the best-fit power law, in particular a change in slope at r_p~1-2 Mpc/

Satoshi Fujimoto, Norio Kawakami

Using conformal perturbation theory, we show that for some classes of the one-dimensional quantum liquids that possess the Luttinger liquid fixed point in the low energy limit, the Drude weight at finite temperatures is non-vanishing, even when the system is {\it non-integrable} and the total current is not conserved. We also obtain the asymptotically exact

Bo Chen, Ying-Jun Ma, Gui Lu Long

We study a quantum game played by two players with restricted multiple strategies. It is found that in this restricted quantum game Nash equilibrium does not always exist when the initial state is entangled. At the same time, we find that when Nash equilibrium exists the pay off function is usually different from that in the classical counterpart except in s

Elinor K. Irish, K. Schwab

We show two effects as a result of considering the second-order correction to the spectrum of a nanomechanical resonator electrostatically coupled to a Cooper-pair box. The spectrum of the Cooper-pair box is modified in a way which depends on the Fock state of the resonator. Similarly, the frequency of the resonator becomes dependent on the state of the Coop

Stephane Nonnenmacher

We study classical and quantum maps on the torus phase space, in the presence of noise. We focus on the spectral properties of the noisy evolution operator, and prove that for any amount of noise, the quantum spectrum converges to the classical one in the semiclassical limit. The small-noise behaviour of the classical spectrum highly depends on the dynamics

Wojciech Hubert Zurek

We propose and analyze a quantum version of Szilard&#39;s ``one-molecule engine.&#39;&#39; In particular, we recover, in the quantum context, Szilard&#39;s conclusion concerning the free energy ``cost&#39;&#39; of measurements: $ΔF \geq k_B T\ln2$ per bit of information.

Charles Ofria, Christoph Adami, Travis C. Collier

We describe the evolution of macromolecules as an information transmission process and apply tools from Shannon information theory to it. This allows us to isolate three independent, competing selective pressures that we term compression, transmission, and neutrality selection. The first two affect genome length: the pressure to conserve resources by compres

G. W. Ford, R. F. O&#39;Connell

In a letter to Nature (Ford G W and O&#39;Connell R F 1996 Nature 380 113) we presented a formula for the derivative of the hyperbolic cotangent that differs from the standard one in the literature by an additional term proportional to the Dirac delta function. Since our letter was necessarily brief, shortly after its appearance we prepared a more extensive

K. G. H. Vollbrecht, R. F. Werner, M. M. Wolf

We investigate the irreversibility of entanglement distillation for a symmetric d-1 parameter family of mixed bipartite quantum states acting on Hilbert spaces of arbitrary dimension d x d. We prove that in this family the entanglement cost is generically strictly larger than the distillable entanglement, such that the set of states for which the distillatio

Peter Rowlands

The nilpotent Dirac formalism has been shown, in previous publications, to generate new physical explanations for aspects of particle physics, with the additional possibility of calculating some of the parameters involved in the Standard Model. The applications so far obtained are summarised, with an outline of some more recent developments.

Aalok Pandya

In this note we comment on yet another way of describing metric of quantum states with the Lorentzian signature. For this, we consider the metric of quantum states and make successive transformations, exploiting the relationship between S3 and SU(2).

Martin Stoll, Thorsten Koehler, Gerhard C. Hegerfeldt

Exciting experiments in the field of atom and molecule optics have lately drawn much attention to the effects involved in the coherent diffraction of particle beams. We review the influence of the finite size of the particles and of their energy level spectrum on the diffraction pattern. In turn, we demonstrate how experimental diffraction measurements allow

Paolo Facchi, Yoichi Nakaguro, Hiromichi Nakazato, Saverio Pascazio

A neutron-spin experimental test of the quantum Zeno effect (QZE) is discussed from a practical point of view, when the nonideal efficiency of the magnetic mirrors, used for filtering the spin state, is taken into account. In the idealized case the number N of (ideal) mirrors can be indefinitely increased, yielding an increasingly better QZE. By contrast, in

Asher Peres, Daniel R. Terno

Relativistic effects affect nearly all notions of quantum information theory. The vacuum behaves as a noisy channel, even if the detectors are perfect. The standard definition of a reduced density matrix fails for photon polarization because the transversality condition behaves like a superselection rule. We can however define an effective reduced density ma

Mitsuro Sugita, Susumu Machida, Yoshihisa Yamamoto

We propose a scheme for the quantum nondemolition (QND) measurement of a single electron spin in a single quantum dot (QD). Analytical expressions are obtained for the optical Faraday effect between a quantum dot exciton and microcavity field. The feasibility of the QND measurement of a single electron spin is discussed for a GaAs/AlAs microcavity with an In

L. Marie, J. Burguete, F. Daviaud, J. Leorat

A numerical study of the magnetic induction equation has been performed on von Karman type flows. These flows are generated by two co-axial counter-rotating propellers in cylindrical containers. Such devices are currently used in the von Karman sodium (VKS) experiment designed to study dynamo action in an unconstrained flow. The mean velocity fields have bee

Md. Ashrafuzzaman, Ahmed Shafee

The interaction energies between the different types of bases of a single strand of DNA molecule have been calculated. Using these original values of energies the harmonic behavior of a number of base patterns of DNA has been studied. In view of the great interest aroused by the discovery of the role of the telomere segment of the DNA in the replication proc

J. Polygiannakis, P. Preka-Papadema, X. Moussas

We show that the continuous wavelet transform can provide a unique decomposition of a timeseries in to &#39;signal-like&#39; and &#39;noise-like&#39; components: From the overall wavelet spectrum two mutually independent skeleton spectra can be extracted, allowing the separate detection and monitoring in even non-stationary timeseries of the evolution of (a)

P. Maris, C. D. Roberts

Dyson-Schwinger equations furnish a Poincare' covariant framework within which to study hadrons. A particular feature is the existence of a nonperturbative, symmetry preserving truncation that enables the proof of exact results. The gap equation reveals that dynamical chiral symmetry breaking is tied to the long-range behaviour of the strong interaction, whi

Reinhard Alkofer, Christian S. Fischer, Lorenz von Smekal

In Landau gauge QCD the Kugo-Ojima confinement criterion and its relation to the infrared behaviour of the gluon and ghost propagators are reviewed. It is demonstrated that the realization of this confinement criterion (which is closely related to the Gribov-Zwanziger horizon condition) results from quite general properties of the ghost Dyson-Schwinger equat

Al. H. Raduta, Ad. R. Raduta

This is a reply to the the nucl-th/0203059 manuscript by Botvina and Mishustin. We show that their pressure versus volume curves (converging to finite values when the system&#39;s density approaches the normal nuclear density) are not realistic. Some other comments are also included.

V. Baru, J. Haidenbauer, C. Hanhart, J. A. Niskanen

We present a new parameterization of the trinucleon wavefunction. As a novel feature a separable parameterization for the complete wavefunction is given. In this way any calculation that considers two body forces only is largely simplified. To demonstrate this we calculate the $π^3$He scattering length.

Jeff Porter, Mary Silber

Many of the interesting patterns seen in recent multi-frequency Faraday experiments can be understood on the basis of three-wave interactions (resonant triads). In this paper we consider two-frequency forcing and focus on a resonant triad that occurs near the bicritical point where two pattern-forming modes with distinct wavenumbers emerge simultaneously. Th

M. A. Reyes, D. Jimenez, H. C. Rosu

Using a combination of the ladder operators of Pina [Rev. Mex. Fis. 41 (1995) 913] and the parametric operators of Mielnik [J. Math. Phys. 25 (1984) 3387] we introduce second order linear differential equations whose eigenfunctions are isospectral to the special functions of the mathematical physics and illustrate the method with several key examples

Pavel Exner

We investigate the operator $-Δ-αδ(x-Γ)$ in $L^2(\mathbb{R}^3)$, where $Γ$ is a smooth surface which is either compact or periodic and satisfies suitable regularity requirements. We find an asymptotic expansion for the lower part of the spectrum as $α\to\infty$ which involves a ``two-dimensional&#39;&#39; comparison operator determined by the geometry of the

M. Baake, R. V. Moody, C. Richard, B. Sing

This review revolves around the question which general distribution of scatterers (in a Euclidean space) results in a pure point diffraction spectrum. Firstly, we treat mathematical diffration theory and state conditions under which such a distribution has pure point diffraction. We explain how a cut and project scheme naturally appears in this context and t

Robin Hartshorne

We characterize the postulation character of arithmetically Gorenstein curves in ${\mathbb P}^4$. We give conditions under which the curve can be realized in the form $mH-K$ on some ACM surface. Finally, we strengthen a theorem of Watanabe by showing that any general arithmetically Gorenstein curve in ${\mathbb P}^4$ can be obtained from a line by a series o

Xiaobo Liu

In this paper, we study relations among known universal equations for Gromov-Witten invariants at genus 1 and 2.

Joao Paulo Santos

We study the moduli space of rank stable based instantons over a connected sum of q copies of CP^2. For c_2=1 we give the homotopy type of the moduli space. For c_2=2 we compute the cohomology of the moduli space.

Toufik Mansour

In this paper we study the sum $$\sum_{j_1+j_2+...+j_d=n}\prod_{i=1}^d F_{k\cdot j_i},$$ where $d\geq2$ and $k\geq1$.

Huiayu Jian

De Giorgi conjectured in 1979 that if a sequence of parabolic functionals Gamma converges to a limiting functional, then the corresponding gradient flows will converge as well after changing timescale appropriately. This paper studies the Gamma convergence for a kind of parabolic functionals, and it supports the De Giorgi&#39;s conjecture.

Huiayu Jian

De Giorgi conjectured in 1979 that if a sequence of functionals converges in the sense of Gamma-convergence to a limiting functional, then the corresponding gradient flows will converge as well after changing timescale appropriately. It is shown that this conjecture holds true for a rather wide kind of functionals.

Osamu Fujino

We prove the termination of 4-fold canonical flips.

Nefton Pali

We give a generalization, in the context of sheaves, of a classical result of Grothendieck concerning the integrability of connections of type $(0,1)$ over a ${\cal C}^{\infty}$ vector bundle over a complex manifold. We introduce the notion of $\bar{\partial}$-coherent sheaf, which is a ${\cal C}^{\infty}$ notion, and we prove the existence of an (exact) equ

Michael Frank Müller, Nikolai Neumaier

In these notes we consider the usual Fedosov star product on a symplectic manifold $(M,ω)$ emanating from the fibrewise Weyl product $\circ$, a symplectic torsion free connection $\nabla$ on M, a formal series $Ω\in νZ^2_{\rm\tiny dR}(M)[[ν]]$ of closed two-forms on M and a certain formal series s of symmetric contravariant tensor fields on M. For a given sy

Paolo Lisca, Andras I. Stipsicz

Extending our earlier results, we prove that certain tight contact structures on circle bundles over surfaces are not symplectically semi--fillable, thus confirming a conjecture of Ko Honda.

Elisabeth Remm, Michel Goze

The complete affine structures on abelian Lie algebras in small dimensions are well known. In this paper we are interested by the non complete case. In particular we classify all these structures in dimensions 2 and 3.

Olalla A. Castro-Alvaredo, Andreas Fring

We present two applications of quantum integrable systems. First, we predict that it is possible to generate high harmonics from solid state devices by demostrating that the emission spectrum for a minimally coupled laser field of frequency $ω$ to an impurity system of a quantum wire, contains multiples of the incoming frequency. Second, evaluating expressio

Klaus Behrndt

In this talk I discuss intersecting brane configurations coming from explicit metrics with G_2 holonomy. An example of a 7-manifold which representing a R^3 bundle over a self-dual Einstein space is described and the potential appearing after compactification over the 6-d twistor space is derived.

Washington Taylor

These lectures provide an introduction to the subject of tachyon condensation in the open bosonic string. The problem of tachyon condensation is first described in the context of the low-energy Yang-Mills description of a system of multiple D-branes, and then using the language of string field theory. An introduction is given to Witten&#39;s cubic open boson