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August 2004 arXiv papers — page 19

Showing 1,801–1,900 of 3,254 papers

  1. M. A. Morales, N. Nygaard, J. E. Williams, Charles W. Clark

    We consider an ideal gas of Bose and Fermi atoms in a harmonic trap, with a Feshbach resonance in the interspecies atomic scattering that can lead to formation of fermionic molecules. We map out the phase diagram for this three-component mixture in chemical and thermal equilibrium. Considering adiabatic association and dissociation of the molecules, we ident

  2. R. H. He

    The application of global non-analytical fit to the quantitative spectral analysis of the bilayer-split peak-dip-hump lineshape of Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ at $(π,0)$ are revisited. The robustness of the results is verified by various fitting schemes confirming physically the correlation of the superconducting peak with the superfluid density.

  3. Zhenyu Li, Jinlong Yang, J. G. Hou, Qingshi Zhu

    We report a first-principles projector augmented wave (PAW) study on Na$_{0.5}$CoO$_2$. With the sodium ion ordered insulating phase being identified in experiments, pure density functional calculations fail to predict an insulating ground state, which indicates that Na ordering alone can not produce accompanying Co charge ordering, if additional correlation

  4. Andrew Das Arulsamy

    The resistivity, $ρ$ as a function of temperature and ionization energy (doping) and magnetization respectively is derived with further confinements from spin-disorder scattering. The computed $T_{crossover}$ below $T_C$ and carrier density in Ga$_{1-x}$Mn$_x$As system are 8-12 K and 10$^{19}$ cm$^{-3}$, remarkably identical with the experimental values of 1

  5. Andrew Das Arulsamy

    Quantitative differences of Lagrange multipliers between standard Fermi-Dirac statistics (FDS) and Ionization energy ($E_I$) based FDS (iFDS) are analyzed in detail to obtain reasonably accurate interpretations without violating the standard FDS. The resistivity and Hall-resistance models in 1D, 2D and 3D are also derived to illustrate the transport phenomen

  6. Robi Banerjee, Ralph E. Pudritz, Lindsay Holmes

    We present a detailed study of the collapse of molecular cloud cores using high resolution 3D adaptive mesh refinement (AMR) numerical simulations. In this first in a series of investigations our initial conditions consists of spherical molecular core obeying the hydrostatic Bonnor-Ebert-Profile with varying degrees of initial rotation. Our simulations cover

  7. R. Misra, K. Shanthi

    Nearly $1.32 \times 10^6$ sec of non-zero count rate data were obtained from five years of {\rm RXTE} observations of the atoll source 4U 1636-53. The data was divided into 10309 segments of 128 sec each. The histogram of the number of segments as a function of count rate shows that the system can naturally be classified into four flux states. For each segme

  8. Marta Anguiano, Giampaolo Co', Antonio M. Lallena

    The photo-emission of two protons from the $^{12}$C, $^{16}$O and $^{40}$Ca nuclei is investigated. Aim of the work is the study of the possibilities offered by this probe to obtain information about the characteristics of the short-range correlations. We have also evaluated the effects of the two-body $Δ$-currents which, in this processes, compete with thos

  9. A. G. Ramm

    Let $A(k)u(k)=f(k) (1)$ be an operator equation, $X$ and $Y$ are Banach spaces, $k\inΔ\subset\C$ is a parameter, $A(k):X\to Y$ is a map, possibly nonlinear. Sufficient conditions are given for continuity of $u(k)$ with respect to $k$. Necessary and sufficient conditions are given for the continuity of $u(k)$ with respect to $k$ in the case of linear operator

  10. Patricio Gaete, Clovis Wotzasek

    We study the static quantum potential for a theory of anti-symmetric tensor fields that results from the condensation of topological defects, within the framework of the gauge-invariant but path-dependent variables formalism. Our calculations show that the interaction energy is the sum of a Yukawa and a linear potentials, leading to the confinement of static

  11. Pascal Baseilhac

    The standard generators of tridiagonal algebras, recently introduced by Terwilliger, are shown to generate a new (in)finite family of mutually commuting operators which extends the Dolan-Grady construction. The involution property relies on the tridiagonal algebraic structure associated with a deformation parameter $q$. Representations are shown to be genera

  12. B. Csak, L. L. Kiss, A. Retter, A. Jacob

    We present a spectroscopic monitoring of the transient nova V4745 Sagittarii (Nova Sgr 2003 #1) covering ten months after the discovery. During this period the light curve showed well expressed transient phase in the form of six rebrightenings, and the presented dataset is one of the best spectroscopic coverages of a classical nova during the transition phas

  13. Tianjun Li, S. Nandi

    We consider a new physics possibility at the colliders: the observation of TeV scale massive vector bosons in the non-adjoint representations under the Standard Model (SM) gauge symmetry. To have a unitary and renormalizable theory, we propose a class of models with gauge symmetry $\prod_i G_i \times SU(3)'_C \times SU(2)'_L \times U(1)'_Y$ where

  14. J. D. Franson, B. C. Jacobs, T. B. Pittman

    We show that the quantum Zeno effect can be used to suppress the failure events that would otherwise occur in a linear optics approach to quantum computing. From a practical viewpoint, that would allow the implementation of deterministic logic gates without the need for ancilla photons or high-efficiency detectors. We also show that the photons can behave as

  15. B. A. Nikolov, D. A. Trifonov

    The geometric quantization problem is considered from the point of view of the Davies and Lewis approach to quantum mechanics. The influence of the measuring device is accounted in the classical and quantum case and it is shown that the conditions of the measurement define the type of quantization (Weyl, normal, antinormal, etc.). The quantum states and quan

  16. N. Gisin

    The slogan information is physical has been so successful that it led to some excess. Classical and quantum information can be thought of independently of any physical implementation. Pure information tasks can be realized using such abstract c- and qu-bits, but physical tasks require appropriate physical realizations of c- or qu-bits. As illustration we con

  17. Geir Ove Myhr

    I give an overview of some of the most used measures of entanglement. To make the presentation self-contained, a number of concepts from quantum information theory are first explained. Then the structure of bipartite entanglement is studied qualitatively, before a number of bipartite entanglement measures are described, both for pure and mixed states. Result

  18. R. B. Laughlin

    There is increasing circumstantial evidence that the cuprate superconductors, and correlated-electron materials generally, defy simple materials categorization because of their proximity to one or more continuous zero-temperature phase transitions. This implies that the fifteen-year confusion about the cuprates is not fundamental at all but simply overinterp

  19. P. K. Panda, D. P. Menezes, C. Providência, J. Da Providência

    In the present work short range correlations are introduced for the first time in a relativistic approach to the equation of state of the infinite nuclear matter in the framework of the Hartree-Fock approximation using an effective Hamiltonian derived from the $σ-ω$ Walecka model. The unitary correlation method is used to introduce short range correlations.

  20. Jian Liu, Zhen-Su She, Hongyu Guo, Liang Li

    We develop a hierarchical structure (HS) analysis for quantitative description of statistical states of spatially extended systems. Examples discussed here include an experimental reaction-diffusion system with Belousov-Zhabotinsky kinetics, the two-dimensional complex Ginzburg-Landau equation and the modified FitzHugh-Nagumon equation, which all show comple

  21. Guy Katriel

    We prove existence results for travelling waves in discrete, damped, dc-driven sine-Gordon equations with periodic boundary conditions.

  22. Marcos Jardim

    Admissible locally-free sheaves on P^3, also known in the literature as mathematical instanton bundles, arise in twistor theory, and are in 1-1 correspondence with instantons on R^4. In this paper, we study admissible sheaves on P^3 from the algebraic geometric point of view. We discuss examples and compare the admissibility condition with semistability and

  23. A. G. Ramm, A. Smirnova

    An optimal algorithm is described for solving the deconvolution problem of the form ${\bf k}u:=\int_0^tk(t-s)u(s)ds=f(t)$ given the noisy data $f_δ$, $||f-f_δ||\leq δ.$ The idea of the method consists of the representation ${\bf k}=A(I+S)$, where $S$ is a compact operator, $I+S$ is injective, $I$ is the identity operator, $A$ is not boundedly invertible, and

  24. W. Chen, A. G. Ramm

    A numerical algorithm is presented for solving the direct scattering problems by the Modified Rayleigh Conjecture Method (MRC) introduced by A.G.Ramm. Some numerical examples are given. They show that the method is numerically efficient.

  25. A. G. Ramm

    Let $F$ be a nonlinear map in a real Hilbert space $H$. Suppose that $\sup_{u\in B(u_0,R)}$ $\|[F'(u)]^{-1}\|\leq m(R)$, where $B(u_0,R)=\{u:\|u-u_0\|\leq R\}$, $R>0$ is arbitrary, $u_0\in H$ is an element. If $\sup_{R>0}\frac{R}{m(R)}=\infty$, then $F$ is surjective. If $\|[F'(u)]^{-1}\|\leq a\|u\|+b$, $a\geq 0$ and $b>0$ are constants independent o

  26. A. G. Ramm

    The aim of this note is to prove a new discrepancy principle. The advantage of the new discrepancy principle compared with the known one consists of solving a minimization problem approximately, rather than exactly, and in the proof of a stability result.

  27. Guoce Xin

    We obtain two new algorithms for partial fraction decompositions; the first is over algebraically closed fields, and the second is over general fields. These algorithms takes $O(M^2)$ time, where $M$ is the degree of the denominator of the rational function. The new algorithms use less storage space, and are suitable for parallel programming. We also discuss

  28. Christopher Allday, Volker Puppe

    In our book on cohomological methods in transformation groups the minimal Hirsch-Brown model was used to good effect. The construction there, however, was rather abstract. Here, for smooth compact connected Lie group actions on smooth closed manifolds, we give a much more explicit construction of the minmal Hirsch-Brown model using operators from classical H

  29. Peter Howard, Kevin Zumbrun

    Using a simplified pointwise iteration scheme, we establish nonlinear phase-asymptotic orbital stability of large-amplitude Lax, undercompressive, overcompressive, and mixed under--overcompressive type shock profiles of strictly parabolic systems of conservation laws with respect to initial perturbations $|u_0(x)|\le E_0 (1+|x|)^{-3/2}$ in $C^{0+α}$, $E_0$ s

  30. Ian G. Moss, James P Norman

    This paper addresses the radiation back reaction problem for cosmological branes. A general framework is provided in which results are given for the radiation reaction with massles and massive scalar fields with flat extra dimensions and massless conformal fields in anti-de Sitter extra dimensions. For massless scalar field radiation the back reaction terms

  31. Gordon L. Kane, Malcolm J. Perry, Anna N. Zytkow

    Motivated by our earlier argument that the apparent large cosmological constant from quantum fluctuations is actually an artifact of not using a full quantum mechanical superposition to determine the ground state in which the universe lives in the de Sitter space at the beginning of inflation, we calculate the tunneling probability for the two-well potential

  32. Paul Korbel

    The main purpose of this paper is to rethink the relativity issue within the framework of the fundamental postulates of quantum mechanics. The aspect of so-called ``double special relativity'' (DSR) is a starting point in our discussion. The three elementary ideas were involved to show that special relativity may be treated as an integral part of qua

  33. Kyungsik Kang, Igor Kondrashuk

    We consider effective action for the Einstein gravity and show that dressed mean fields are actual variables of the effective action. Kernels of this effective action expressed in terms of dressed effective fields are constituent parts of scattering amplitudes for gravitons. Possible applications to the graviton scattering and black hole formation are discus

  34. S. Atag, I. Sahin

    The constraints on the neutral gauge boson couplings, $ZZγ$ and $Zγγ$, are investigated at linear $e^{+}e^{-}$ collider energies through the $Zγ$ production with longitudinal and transverse polarization states of the final Z boson. Because of high energy of linear electron- positron beams, initial state radiation (ISR) considerably changes the production cro

  35. A. R. Taurines, A. Cucchieri, T. Mendes

    We consider numerical data for the lattice Landau gluon propagator obtained at very large lattice volumes in three-dimensional pure SU(2) Yang-Mills gauge theory (YM^2_3). We find that the temporal correlator C(t) shows an oscillatory pattern and is negative for several values of t. This is an explicit violation of reflection positivity and can be related to

  36. A. Mihara, A. Cucchieri, T. Mendes

    It is well known that, in Landau gauge, the renormalization function of the ghost-ghost-gluon vertex \widetilde{Z}_1(p^2) is finite and constant, at least to all orders of perturbation theory. On the other hand, a direct non-perturbative verification of this result using numerical simulations of lattice QCD is still missing. Here we present a preliminary num

  37. The BABAR Collaboration, B. Aubert

    We present the preliminary result of a search for the decay of $B^0\to K^{*+}ρ^-$. The data were recorded with the $BaBar$ detector at the PEPII collider and correspond to 123 million $B\bar{B}$ pairs produced in the $e^+e^-$ annihilation through the $Υ(4S)$ resonance. We obtain an upper limit on the branching fraction for this decay of ${\cal B}(B^0\to K^{*

  38. The BABAR Collaboration, B. Aubert

    We present measurements of the branching fraction and time-dependent CP-violating (CPV) asymmetries in B0 --> K0S Pi0 decays based on 227 million Y(4S) --> BBbar decays collected with the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC. We obtain a branching fraction B(B0 --> K0 Pi0) = (11.4 +/- 0.9 +/- 0.6) x 10^{-6}, the magnitude of the d

  39. B. Aubert, BABAR Collaboration

    The B --> rho0 rho0 decay mode is searched for in a data sample of about 227 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at the PEP-II asymmetric B factory at SLAC. No significant signal is observed, and an upper limit of 1.1 x 10e-6 (90% C.L.) on the branching fraction is set. Implications on the penguin contribution and constrai

  40. The BABAR Collaboration, B. Aubert

    We present a study of the decays B- --> D*0 pi- and B- --> D*0 K-, where the D*0 decays into D0 pi0, with the D0 reconstructed in the CP eigenstates K- K+ and pi- pi+ and in the (non-CP) channels K- pi+, K- pi+ pi+ pi-, and K- pi+ pi0. We use an unbinned maximum likelihood fit to measure the signal yields. Using a sample of about 123 million Y(4S) decays int

  41. The BABAR Collaboration, B. Aubert

    We present a preliminary measurement of CP-violating asymmetries in fully reconstructed $B^0{\to}D^{(*)\pm}π^{\mp}$ and $\B^0{\to}D^{\pm}ρ^{\mp}$ decays in approximately 110 million $Υ(\rm 4S) \to B\bar{B}$ decays collected with the BaBar detector at the PEP-II asymmetric-energy $B$ factory at SLAC. % From a maximum likelihood fit to the time-dependent decay

  42. Mark D. Roberts

    A common method of making a theory more understandable, is by comparing it to another theory which has been better developed. Radical interpretation is a theory which attempts to explain how communication has meaning. Radical interpretation is treated as another time-dependent theory and compared to the time dependent theory of biological evolution. The main

  43. Jim Gray, Leslie Lamport

    The distributed transaction commit problem requires reaching agreement on whether a transaction is committed or aborted. The classic Two-Phase Commit protocol blocks if the coordinator fails. Fault-tolerant consensus algorithms also reach agreement, but do not block whenever any majority of the processes are working. Running a Paxos consensus algorithm on th

  44. David Oppenheimer, Vitaliy Vatkovskiy, Hakim Weatherspoon, Jason Lee

    Analyzing and controlling large distributed services under a wide range of conditions is difficult. Yet these capabilities are essential to a number of important development and operational tasks such as benchmarking, testing, and system management. To facilitate these tasks, we have built the Application Control and Monitoring Environment (ACME), a scalable

  45. Jim Gray, Alexander S. Szalay, Aniruddha R. Thakar, Gyorgy Fekete

    We explored ways of doing spatial search within a relational database: (1) hierarchical triangular mesh (a tessellation of the sphere), (2) a zoned bucketing system, and (3) representing areas as disjunctive-normal form constraints. Each of these approaches has merits. They all allow efficient point-in-region queries. A relational representation for regions

  46. Jim Gray

    Database system architectures are undergoing revolutionary changes. Algorithms and data are being unified by integrating programming languages with the database system. This gives an extensible object-relational system where non-procedural relational operators manipulate object sets. Coupled with this, each DBMS is now a web service. This has huge implicatio

  47. S. Rayaprol, Darshan C. Kundaliya, C. M. Thaker, D. G. Kuberkar

    The La-2125 type La2-xDyxCa2xBa2Cu4+2xOz (0.1 < x < 0.5; LDBO) compounds have been synthesized and studied for their structural and superconducting properties by room temperature neutron diffraction, high field dc magnetization, four-probe resistivity and iodometric double titration. The Rietveld analysis of the neutron diffraction data reveals tetragonal st

  48. S. Rayaprol, Rohini Parmar, D. G. Kuberkar, Keka R. Chakraborty

    Structural studies on Dy-substituted La-2125 type superconductors have been carried out by neutron diffraction experiments at room temperature using a monochromatic neutron beam of wavelength lambda = 1.249 Angstroms. A series of samples with La2-xDyxCa2xBa2Cu4+2xOz stoichiometric composition, for x = 0.1 - 0.5, have been studied for their structural propert

  49. Ming-Hao Liu, Ching-Ray Chang, Son-Hsien Chen

    We present the analytical result of the expectation value of spin resulting from an injected spin polarized electron into a semi-infinitely extended 2DEG plane with [001] growth geometry via ideal quantum point contact. Both the Rashba and Dresselhaus spin-orbit couplings are taken into account. A pictorial interpretation of the spin precession along certain

  50. Ernesto P. Borges

    We present a deformed algebra related to the q-exponential and the q-logarithm functions that emerge from nonextensive statistical mechanics. We also develop a q-derivative (and consistently a q-integral) for which the q-exponential is an eigenfunction. The q-derivative and the q-integral have a dual nature, that is also presented.

  51. Daisuke Nagai, Andrey V. Kravtsov

    We study the radial distribution of subhalos and galaxies using high-resolution cosmological simulations of galaxy clusters formed in the concordance LCDM cosmology. In agreement with previous studies, we find that the radial distribution of subhalos is significantly less concentrated than that of the dark matter, when subhalos are selected using their prese

  52. Sergey A. Astakhov, David Farrelly

    Several families of irregular moons orbit the giant planets. These moons are thought to have been captured into planetocentric orbits after straying into a region in which the planet&#39;s gravitation dominates solar perturbations (the Hill sphere). This mechanism requires a source of dissipation, such as gas-drag, in order to make capture permanent. However

  53. Yang-Chan Jung, Hee-Won Lee

    We present our spectroscopic data around H$β$ of the symbiotic star V1016 Cyg obtained with the Bohyunsan Echelle Spectrograph, in order to secure the broad emission feature at around 4850Å, which is formed through Raman scattering of He II $λ$ 972. The total cross section around Ly$γ$ is approximately given by $σ(λ)\simeq 1.7\times 10^{-28}[λ_{Lyγ}/(λ-λ_{Ly

  54. Jae-Woo Lee, Bruce W. Carney, Suchitra C. Balachandran

    We present high-resolution infrared echelle spectroscopy for the globular clusters Palomar 6 and M71. Our mean heliocentric radial velocity of Palomar 6 is +180.6 +/- 3.2 km sec/s and is 20 km/s lower than that found by Minniti in 1995. Contrary to the previous metallicity estimates using low-resolution spectroscopy, our results show that Palomar~6 has an in

  55. S. Jogee, F. D. Barazza, H. -W. Rix, J. Davies

    Bars drive the dynamical evolution of disk galaxies by redistributing mass and angular momentum, and they are ubiquitous in present-day spirals. Early studies of the Hubble Deep Field reported a dramatic decline in the rest-frame optical bar fraction f_opt to below 5% at redshifts z>0.7, implying that disks at these epochs are fundamentally different from pr

  56. Christian W. Bauer, Dan Pirjol

    We discuss the relationship between the graphical amplitudes T, C, P, ... used to parameterize nonleptonic B decay amplitudes, and matrix elements of operators in the soft-collinear effective theory (SCET) at leading order in Λ/m_b. Using the SU(3) flavor symmetry of the weak Hamiltonian we derive all-order constraints on the electroweak penguin contribution

  57. J. Maíz-Apellániz, H. E. Bond, M. H. Siegel, Y. Lipkin

    The Type II-P supernova 2004dj in the nearby galaxy NGC 2403 occurred at a position coincident with object 96 in the list of luminous stars and clusters in this galaxy published by Sandage in 1984. The coincidence is established definitively through astrometric registration of our ground-based archival images of NGC 2403 with our recent images showing the SN

  58. F. Benmokhtar

    Results of the Jefferson Lab Hall A quasielastic 3He(e,e&#39;p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q = 1502 MeV/c and omega = 840 MeV, respectively, for missing momenta p_m up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much mo

  59. K. P Yogendran

    We study D-branes in the Lorentzian signature 2D black hole string theory. We use the technique of gauged WZW models to construct the associated boundary conformal field theories. The main focus of this work is to discuss the (semi-classical) world-volume geometries of the D-branes. We also discuss comparison of our work with results in related gauged WZW mo

  60. B. Aubert, BABAR Collaboration

    Branching fraction measurements using B-meson decays to Kspi+pi- are presented. These measurements were obtained by analyzing a data sample of 88.9 million Y(4S) --> BB decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy B factory. Using a maximum likelihood fit, the following branching fraction results were obtained: Br(B0 -> K0pi+

  61. Ronald A. Downes, Bruce Margon, Lee Homer, Scott F. Anderson

    There are extraordinarily few far ultraviolet observations of RR Lyrae stars in the literature. We present Hubble Space Telescope FUV (~1600 A) imaging of the core of the globular cluster NGC 1851. Eleven new variables whose light curves are consistent with those of RR Lyr stars are discovered, increasing the total number of RR Lyr known in this cluster by a

  62. M. B. Gay Ducati, V. P. Goncalves, L. F. Mackedanz

    The D meson production at forward rapidities in d+Au processes is calculated using a pQCD based model, assuming that this treatment could be used as a baseline for distinct dynamical and medium effects. It is analysed how the nuclear effects in the nuclear partonic distributions may affect this process at RHIC and LHC energies. An enhancement in the moderate

  63. T. Aushev

    We report a search for CP-violating asymmetry in B0 -> D*+- D-+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D*+ -> D0 pi_slow+

  64. T. B. Pittman, B. C Jacobs, J. D. Franson

    We describe an experiment in which photon pairs from a pulsed parametric down-conversion source were coupled into single-mode fibers. Detecting one of the photons heralded the presence of the other photon in its fiber with a probability of 83%. The heralded photons were then used in a simple multi-photon interference experiment to illustrate their potential

  65. M. Halder, S. Tanzilli, H. de Riedmatten, A. Beveratos

    To show the feasibility of a long distance partial Bell-State measurement, a Hong-Ou-Mandel experiment with coherent photons is reported. Pairs of degenerate photons at telecom wavelength are created by parametric down conversion in a periodically poled lithium niobate waveguide. The photon pairs are separated in a beam-splitter and transmitted via two fiber

  66. Johanna Erdmenger, Ingo Kirsch

    In view of extending gauge/gravity dualities with flavour beyond the probe approximation, we establish the gravity dual description of mesons for a three-dimensional super Yang-Mills theory with fundamental matter. For this purpose we consider the fully backreacted D2/D6 brane solution of Cherkis and Hashimoto in an approximation due to Pelc and Siebelink. T

  67. Yoshiteru Amemiya, Kenji Araki, So Katagiri

    A Dp-brane can be regarded as a configuration of infinitely many D(p-2k)-branes in bosonic string. We will show this property of D-branes in the superstring case using the hybrid formalism. It is convenient to study the boundary state for such D-branes to study such property between D-branes. We show that the boundary state for a D3-brane in a constant self-

  68. A. P. Balachandran, Giorgio Immirzi

    Nonlinear `sigma&#39; models in two dimensions have BPS solitons which are solutions of self- and anti-self-duality constraints. In this paper, we find their analogues for fuzzy sigma models on fuzzy spheres which were treated in detail by us in earlier work. We show that fuzzy BPS solitons are quantized versions of `Bott projectors&#39;, and construct them

  69. L. F. Wei, Yu-xi Liu, Franco Nori

    In superconducting circuits with interbit untunable (e.g., capacitive) couplings, ideal local quantum operations cannot be exactly performed on individual Josephson qubits. Here we propose an effective dynamical decoupling approach to overcome the &#34;fixed-interaction&#34; difficulty for effectively implementing elemental logical gates for quantum computat

  70. P. Vielva, E. Martinez-Gonzalez, M. Tucci

    We report the first detection of the ISW effect in wavelet space, at scales in the sky around 7 degrees with a significance of around 3.3 sigma, by cross-correlating the WMAP first-year data and the NRAO VLA Sky Survey (NVSS). In addition, we present a detailed comparison among the capabilities of three different techniques for two different objectives: to d

  71. G. F. Giudice, A. Riotto, A. Zaffaroni

    We describe a simple and efficient mechanism by which very heavy particles are copiously created from a primordial inflationary epoch. It works for scalar fields which are massless or very light during inflation and acquire a large mass right after the end of inflation. Such particles can exist in realistic scenarios, as we illustrate with several examples i

  72. Jounghun Lee

    We investigate analytically a large-scale coherence in the orientation of galaxies embedded in two-dimensional sheet-like structures in the frame of the tidal torque theory. Assuming that the galaxy spin and the surrounding matter fields are intrinsically aligned in accordance with the tidal torque model, we first derive analytically the probability distribu

  73. Dagomir Kaszlikowski, Jenn Yang Lim, D. K. L. Oi, Frederick H. Willeboordse

    We present a generalized tomographic quantum key distribution protocol in which the two parties share a Bell diagonal mixed state of two qubits. We show that if an eavesdropper performs a coherent measurement on many quantum ancilla states simultaneously, classical methods of secure key distillation are less effective than quantum entanglement distillation p

  74. Ralf Schützhold, Markus Tiersch

    By means of two simple examples: phase and amplitude damping, the impact of decoherence on the dynamical Casimir effect is investigated. Even without dissipating energy (i.e., pure phase damping), the amount of created particles can be diminished significantly via the coupling to the environment (reservoir theory) inducing decoherence. For a simple microscop

  75. C. P. Burgess, F. Quevedo, G. Tasinato, I. Zavala

    We re-examine the properties of the axially-symmetric solutions to chiral gauged 6D supergravity, recently found in refs. hep-th/0307238 and hep-th/0308064. Ref. hep-th/0307238 finds the most general solutions having two singularities which are maximally-symmetric in the large 4 dimensions and which are axially-symmetric in the internal dimensions. We show t

  76. Jinn-Ouk Gong

    We derive the power spectrum P_ψ(k) of the gravitational waves produced during general classes of inflation with second order corrections. Using this result, we also derive the spectrum and the spectral index in the standard slow-roll approximation with new higher order corrections.

  77. J. Yang, W. H. Song, Y. Q. Ma, R. L. Zhang

    The possible redox (oxidation reduction) chemical methods for precisely determining the oxygen content in the perovskite manganites including hole-doped La1-xCaxMnOy and electron-doped La1-xTexMnOy compounds are described. For manganites annealed at different temperatures, the oxygen content of the samples was determined by a redox back titration in which th

  78. J. Yang, B. C. Zhao, R. L. Zhang, Y. Q. Ma

    The effect of grain size on structural, magnetic and transport properties in electron-doped manganites La0.9Te0.1MnO3 has been investigated. All samples show a rhombohedral structure with the space group at room temperature. It shows that the Mn-O-Mn bond angle decreases and the Mn-O bond length increases with the increase of grain size. All samples undergo

  79. J. Yang, W. H. Song, Y. Q. Ma, R. L. Zhang

    The effect of Cu-doping at Mn-site on structural, magnetic and transport properties in electron-doped manganites La0.85Te0.15Mn1-xCuxO3 has been investigated. Based on the analysis of structural parameter variations, the valence state of the Cu ion in Cu-doped manganites is suggested to be +2. All samples undergo the paramagnetic-ferromagnetic (PM-FM) phase

  80. J. -C. Boileau, K. Tamaki, J. Batuwantudawe, R. Laflamme

    Quantum key distribution (QKD) protocols are cryptographic techniques with security based only on the laws of quantum mechanics. Two prominent QKD schemes are the BB84 and B92 protocols that use four and two quantum states, respectively. In 2000, Phoenix et al. proposed a new family of three state protocols that offers advantages over the previous schemes. U

  81. Lech Jakobczyk, Anna Jamroz

    We discuss the influence of a noisy environment on entangled states of two atoms and show that all such states disentangle in finite time.

  82. S. Shresta, C. Anastopoulos, A. Dragulescu, B. L. Hu

    We study the non-Markovian dynamics of a qubit made up of a two-level atom interacting with an electromagnetic field (EMF) initially at finite temperature. Unlike most earlier studies where the bath is assumed to be fixed, we study the coherent evolution of the combined qubit-EMF system, thus allowing for the back-action from the bath on the qubit and the qu

  83. Ganesh Bagler, Somdatta Sinha

    Protein structures can be studied as complex networks of interacting amino acids. We study proteins of different structural classes from the network perspective. Our results indicate that proteins, regardless of their structural class, show small-world network property. Various network parameters offer insight into the structural organisation of proteins and

  84. D. Oliva, I. Samengo, S. Leutgeb, S. Mizumori

    As subjects perceive the sensory world, different stimuli elicit a number of neural representations. Here, a subjective distance between stimuli is defined, measuring the degree of similarity between the underlying representations. As an example, the subjective distance between different locations in space is calculated from the activity of rodent hippocampa

  85. A. Rudenko, K. Zrost, B. Feuerstein, V. L. B. de Jesus

    We present the results of the detailed experimental study of multiple ionization of Ne and Ar by 25 and 7 fs laser pulses. For Ne the highly correlated &#34;instantaneous&#34; emission of up to four electrons is triggered by a recollisional electron impact, whereas in multiple ionization of Ar different mechanisms, involving field ionization steps and recoll

  86. A. Rudenko, K. Zrost, C. D. Schröter, V. L. B. de Jesus

    We present results of high-resolution experiments on single ionization of He, Ne and Ar by ultra-short (25 fs, 6 fs) 795 nm laser pulses at intensities 0.15-2.0x10^15 W/cm^2. We show that the ATI-like pattern can survive deep in the tunneling regime and that the atomic structure plays an important role in the formation of the low-energy photoelectron spectra

  87. A. Wynveen, D. J. Lee, A. A. Kornyshev

    Many physical systems can be mapped onto solved or &#34;solvable&#34; models of magnetism. In this work, we have mapped the statistical mechanics of columnar phases of ideally helical rigid DNA -- subject to the earlier found unusual, frustrated pair potential [A. A. Kornyshev and S. Leikin, J. Chem. Phys. 107, 3656 (1997)] -- onto an exotic, unknown variant

  88. Anders Levermann, Alexa Griesel, Matthias Hofmann, Marisa Montoya

    Using the coupled climate model CLIMBER-3a, we investigate changes in sea surface elevation due to a weakening of the thermohaline circulation (THC). In addition to a global sea level rise due to a warming of the deep sea, this leads to a regional dynamic sea level change which follows quasi-instantaneously any change in the ocean circulation. We show that t

  89. Anders Levermann, Alexa Griesel

    We present an analysis of the model by Gnanadesikan [1999] for the pycnocline depth in the ocean. An analytic solution for the overturning strength as a function of the meridional pressure difference is derived and used to discuss their mutual scaling. We show that scaling occurs only in two unphysical regimes of the model. In the absence of the Southern Oce

  90. H. M. Mok

    The author proposed in his previous papers in 2001 that the problem of the cosmological constant could be resolved and its calculated value agrees excellently with the observations by assuming that the space-time itself, as the phase of Higgs condensate, is discrete in nature. Further to such idea, a different approach involving the concept of vacuum entropy

  91. Arup Roy

    A relation connecting the {\it{rest mass}} and {\it{separation of events in space-time continuum}} is suggested and the idea of Compton scattering is used as a method for the determination of rest mass. An experiment involving collision of photons resulting in creation of rest mass is discussed theoretically in order to illustrate the connection formula.

  92. Raishma Krishnan, A. M. Jayannavar

    In recent literature there has been a lot of interest in the phenomena of noise induced transport in the absence of an average bias occurring in spatially periodic systems far from equilibrium. One of the main motivations in this area is to understand the mechanism behind the operation of biological motors at molecular scale. These molecular motors convert c

  93. G. H. Rawitscher, I. Koltracht

    The solution of the Lippman-Schwinger (L-S) integral equation is equivalent to the the solution of the Schroedinger equation. A new numerical algorithm for solving the L-S equation is described in simple terms, and its high accuracy is confirmed for several physical situations. They are: the scattering of an electron from a static hydrogen atom in the presen

  94. P. Bydzovsky, M. Sotona

    The CLAS data on the photo-production of K+ off the proton are utilised to study reaction mechanism of the process in frame of the isobaric approach. The missing D13 resonance is shown to be important for successful description of the data in the whole kinematical region. Constructed models provide satisfactory predictions for the process.

  95. Felipe J. Llanes-Estrada, Stephen R. Cotanch

    Recent J = 0 (para) baryonium interpretations of the BES narrow resonance data near the e^-e^+ -> p anti-p threshold suggests the existance of ortho baryonium. To assist future searches we study J = 1 states, especially vector meson leptonic decays, and report RPA calculations for both light and heavy mesons using a Coulomb-gauge QCD-inspired model. Since th

  96. Dan Magestro

    I will present a review of the field of Hanbury Brown-Twiss interferometry in relativistic heavy-ion collisions. The &#34;HBT puzzle&#34; is explored in detail, emphasizing recent theoretical attempts to understand the persisting puzzle. I also present recent experimental results on azimuthally sensitive HBT, HBT of direct photons, and some surprises in the

  97. Aristophanes Dimakis, Folkert Muller-Hoissen

    Moyal-deformed hierarchies of soliton equations can be extended to larger hierarchies by including additional evolution equations with respect to the deformation parameters. A general framework is presented in which the extension is universally determined and which applies to several deformed hierarchies, including the noncommutative KP, modified KP, and Tod

  98. Peng Li

    The fundamental problem of optical wave propagation is the determination of the field at an observation point, given a disturbance specified over some finite aperture. In both vacuum and inhomogeneous media, the solution of this problem is given approximately by the superposition integral, which is a mathematical expression of the extended Huygens-Fresnel pr

  99. Marta Tyran-Kaminska

    We give a general method of deriving statistical limit theorems, such as the central limit theorem and its functional version, in the setting of ergodic measure preserving transformations. This method is applicable in situations where the iterates of discrete time maps display a polynomial decay of correlations.

  100. János Kollár

    The aim of this paper is to study Seifert bundle structures on simply connected 5--manifolds. We classify all such 5--manifolds which admit a Seifert bundle structure, and in a few cases all Seifert bundle structures are also classified. These results are then used to construct positive Ricci curvature Einstein metrics on these manifolds. The proof has 4 mai