July 2006 arXiv papers — page 44

Carlos Barcelo, Stefano Liberati, Sebastiano Sonego, Matt Visser

We discuss the issue of quasi-particle production by ``analogue black holes'' with particular attention to the possibility of reproducing Hawking radiation in a laboratory. By constructing simple geometric acoustic models, we obtain a somewhat unexpected result: We show that in order to obtain a stationary and Planckian emission of quasi-particles, i

Clovis Jacinto de Matos

A gravitomagnetic analogue of the London moment in superconductors can explain the anomalous Cooper pair mass excess reported by Janet Tate. Ultimately the gravitomagnetic London moment is attributed to the breaking of the principle of general covariance in superconductors. This naturally implies non-conservation of classical energy-momentum. Possible relati

Samuel Sattath

Broadly speaking Information theory (IT) assumes no structure of the underlying states. But what about contexts where states do have a clear structure - how should IT cope with such situations? And if such coping is at all possible then - how should structure be expressed so that it can be coped with? A possible answer to these questions is presented here. N

Yuri Pritykin

The paper studies different variants of almost periodicity notion. We introduce the class of eventually strongly almost periodic sequences where some suffix is strongly almost periodic (=uniformly recurrent). The class of almost periodic sequences includes the class of eventually strongly almost periodic sequences, and we prove this inclusion to be strict. W

Fédéric Havet, Jean-Sébastien Sereni, Riste Skrekovski

A plane graph is l-facially k-colourable if its vertices can be coloured with k colours such that any two distinct vertices on a facial segment of length at most l are coloured differently. We prove that every plane graph is 3-facially 11-colourable. As a consequence, we derive that every 2-connected plane graph with maximum face-size at most 7 is cyclically

V. V. Yurchenko, D. V. Shantsev, Y. M. Galperin, A. K. M. Alamgir

An increase in the critical current and suppression of AC losses in superconducting wires and tapes with soft magnetic sheath have been predicted theoretically and confirmed experimentally. In this work we present the results of magneto-optical investigations on a series of Ag-sheathed Bi-2223 tapes with Ni coating. We visualize distributions of magnetic fie

J. Albrecht, A. T. Matveev, J. Strempfer, H. -U. Habermeier

Anisotropic penetration of magnetic flux in MgB2 films grown on vicinal sapphire substrates is investigated using magneto-optical imaging. Regular penetration above 10 K proceeds more easily along the substrate surface steps, anisotropy of the critical current being 6%. At lower temperatures the penetration occurs via abrupt dendritic avalanches that prefere

Frank W. Bentrem, R. B. Pandey, Fereydoon Family

Growth and roughness of the interface of deposited polymer chains driven by a field onto an impenetrable adsorbing surface are studied by computer simulations in (2+1) dimensions. The evolution of the interface width W shows a crossover from short-time growth described by the exponent beta1 to a long-time growth with exponent beta2 (>beta1). The saturated wi

D. J. Durian, H. Bideaud, P. Duringer, A. Schroder

We propose to characterize the shapes of flat pebbles in terms of the statistical distribution of curvatures measured along the pebble contour. This is demonstrated for the erosion of clay pebbles in a controlled laboratory apparatus. Photographs at various stages of erosion are analyzed, and compared with two models. We find that the curvature distribution

Sadhan K. Adhikari

We use the time-dependent mean-field Gross-Pitaevskii equation to study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-one-dimensional Bose-Einstein condensate (BEC). Because of three-body recombination of bosonic atoms to molecules, atoms are lost (dissipated) from a BEC. Such dissipation leads to the decay of a BEC

John R. Clem, Yasunori Mawatari

Domelike magnetic-flux-density distributions previously have been observed experimentally and analyzed theoretically in superconducting films with edges, such as in strips and thin plates. Such flux domes have been explained as arising from a combination of strong geometric barriers and weak bulk pinning. In this paper we predict that, even in films with bul

T. A. Abtew, D. A. Drabold

We study the structural, dynamical and electronic properties of amorphous Si\sub{1-x}Ge\sub{x}:H alloys using first principles local basis molecular dynamics simulation. The network topology and defects in the amorphous network have been analyzed. Structural changes and an increase in number of defects have been found as the Ge atomic percentage increases fr

G. I. Japaridze, R. M. Noack, D. Baeriswyl

We study the quantum phase transition from an insulator to a metal realized at t'=t'_c > 0.5t in the ground state of the half-filled Hubbard chain with both nearest-neighbor (t) and next-nearest-neighbor (t') hopping. The study is carried out using the bosonization approach and density matrix renormalization group calculations. An effective low-e

J. K. Freericks, V. M. Turkowski, V. Zlatic

The many-body formalism for dynamical mean-field theory is extended to treat nonequilibrium problems. We illustrate how the formalism works by examining the transient decay of the oscillating current that is driven by a large electric field turned on at time t=0. We show how the Bloch oscillations are quenched by the electron-electron interactions, and how t

Chee Kwan Gan, Yuan Ping Feng, David J. Srolovitz

The thermodynamics properties of the wurtzite and zinc-blende \InGaN alloys are calculated using first-principles density-functional calculations. Special quasi-random structures are used to describe the disordered alloys, for $x= 1/4, 1/2$, and 3/4. The effect of lattice vibrations on the phase diagram, commonly omitted from semiconductor alloy phase diagra

Paul Tangney, Marvin L. Cohen, Steven G. Louie

Molecular dynamics simulations of coaxial carbon nanotubes in relative sliding motion reveal a striking enhancement of friction when phonons whose group velocity is close to the sliding velocity of the nanotubes are resonantly excited. The effect is analogous to the dramatic increase in air drag experienced by aircraft flying close to the speed of sound, but

Roland Bastardis, Nathalie Guihery, Nicolas Suaud

The Zener polarons recently found in half-doped manganites are usually seen as mixed valence entities ruled by a double exchange Hamiltonian involving only correlated electrons of the metals. They can however be considered as ferrimagnetic local units if the holes are localized on the bridging oxygen atoms as implicitely suggested by recent mean-field it ab

Yu. Chikina, V. Shikin, A. A. Varlamov

The problem of correct definition of the charge carrier effective mass in superfluid helium is revised. It is demonstrated that the effective mass $M$ of a such quasiparticle can be introduced without use of the Atkins's idea concerning the solidification of liquid He in the close vicinity of ion. The two-liquid scenario of the ''snowball'&#3

E. Katzav, M. Adda--Bedia

The dynamics of planar crack fronts in heterogeneous media is studied using a recently proposed stochastic equation of motion that takes into account nonlinear effects. The analysis is carried for a moving front in the quasi-static regime using the Self Consistent Expansion. A continuous dynamical phase transition between a flat phase and a dynamically rough

A. Scala, Th. Voigtmann, C. De Michele

Brownian dynamics algorithms integrate numerically Langevin equations and allow to probe long time scales in simulations. A common requirement for such algorithms is that interactions in the system should vary little during an integration time step: therefore, computational efficiency worsens as the interactions become steeper. In the extreme case of hard-bo

D. Kechrakos, K. N. Trohidou, M. Vasilakaki

We calculate the magnetization hysteresis for an ordered array of composite magnetic nanoparticles with a ferromagnetic (FM) core and an antiferromagnetic (AFM) shell, located on a triangular lattice and coupled via magnetostatic forces. Each nanoparticle is described by a pair of exchange-coupled (J), anisotropic spins (Meiklejohn-Bean model). The magnetiza

M. V. Costache, M. Sladkov, C. H. van der Wal, B. J. van Wees

We measured ferromagnetic resonance of a single submicron ferromagnetic strip, embedded in an on-chip microwave transmission line device. The method used is based on detection of the oscillating magnetic flux due to the magnetization dynamics, with an inductive pick-up loop. The dependence of the resonance frequency on applied static magnetic field agrees ve

Ravi Shankar Singh, Kalobaran Maiti

We investigate the effect of temperature on the electronic and crystal structures of Ca1-xSrxRuO3 via the evolution of O 1s core level spectra as a function of temperature and composition, x. O 1s spectra in SrRuO3 exhibit a dominant sharp feature at all the temperatures with a small trace of impurity feature at higher binding energies. The spectra in Ca dop

B. Stojetz, S. Roche, C. Miko, F. Triozon

Magnetotransport measurements in large diameter multiwall carbon nanotubes (20-40 nm) demonstrate the competition of a magnetic-field dependent bandstructure and Altshuler-Aronov-Spivak oscillations. By means of an efficient capacitive coupling to a backgate electrode, the magnetoconductance oscillations are explored as a function of Fermi level shift. Chang

Hiroyasu Koizumi

Persistent current generation by small polarons embedded in a spin-density wave background in a two dimensional lattice is theoretically studied. When the embedded small polarons become cores of merons and antimerons (vortices in spin configuration with winding numbers +1 and -1, respectively), a spin Berry phase arises from the spiral spin texture of the me

Motoshi Kondo, Shunichi Takada, Yoshiyuki Shibayama, Keiya Shirahama

In recent torsional oscillator experiments by Kim and Chan (KC), a decrease of rotational inertia has been observed in solid 4He in porous materials and in a bulk annular channel. This observation strongly suggests the existence of "non-classical rotational inertia" (NCRI), i.e. superflow, in solid 4He. In order to study such a possible "supersol

David S. Dean, David Lancaster

We study the statistical mechanics of multi-index matching problems where the quenched disorder is a geometric site disorder rather than a link disorder. A recently developed functional formalism is exploited which yields exact results in the finite temperature thermodynamic limit. Particular attention is paid to the zero temperature limit of maximal matchin

T. Masuda, G. J. Redhammer

The compound \CuScGeO is presented as a new member of the family of weakly coupled spin chain and dimer compounds \CuMGeO. Magnetic susceptibility, heat capacity, and neutron inelastic scattering measurements reveal that the compound has the same spin dimer component as \CuFeGeO. The observed narrow band excitation in bulk measurements is consistent with spi

S. Masubuchi, K. Hamaya, T. Machida

A method for the observation of the Knight shift in nanometer-scale region in semiconductors is developed using resistively detected nuclear magnetic resonance (RDNMR) technique in quantum Hall edge channels. Using a gate-induced decoupling of the hyperfine interaction between electron and nuclear spins, we obtain the RDNMR spectra with or without the electr

Yasuhiro Hatsugai

Recently by using quantized Berry phases, a prescription for a local characterization of gapped topological insulators is given. One requires the ground state is gapped and is invariant under some anti-unitary operation. A spin liquid which is realized as a unique ground state of the Heisenberg spin system with frustrations is a typical target system, since

T. Nakaoka, H. J. Krenner, E. C. Clark, M. Sabathil

We probe acoustic phonon mediated relaxation between tunnel coupled exciton states in an individual quantum dot molecule in which the inter-dot quantum coupling and energy separation between exciton states is continuously tuned using static electric field. Time resolved and temperature dependent optical spectroscopy are used to probe inter-level relaxation a

S. V. Streltsov, O. A. Popova, D. I. Khomskii

Magnetic and electronic properties of NaTiSi$_2$O$_6$ in low temperature phase were studied in the framework of the LDA+U approximation. We stress that neglecting correlation effects in LSDA calculations one obtains not only several times smaller value of the band gap, but also fails to describe magnetic properties of NaTiSi$_2$O$_6$. Our LDA+U results confi

J. Stecki

Molecular Dynamics simulations of a model bilayer made of surfactant dimers in a Lennard-Jones solvent are reported for three sizes of the systems up to an area of $100σ\times 100σ$ and for a large interval of specific areas:from hole formation under tension to the floppy state of a compressed bilayer. The transition to the floppy state appears quite abrupt

Lior Shamir, Robert J. Nemiroff

We report on a ~5th magnitude flash detected for approximately 10 minutes by two CONCAM all-sky cameras located in Cerro Pachon - Chile and La Palma - Spain. A third all-sky camera, located in Cerro Paranal - Chile did not detect the flash, and therefore the authors of this paper suggest that the flash was a series of cosmic-ray hits, meteors, or satellite g

B. P. Miller, W. N. Brandt, S. C. Gallagher, A. Laor

We investigate the X-ray properties of PG 1004+130, a low-redshift radio-loud broad absorption line (BAL) quasar with a hybrid FR I/FR II radio morphology. The 22.2 ks XMM-Newton and 41.6 ks Chandra observations presented here are the first X-ray detections of PG 1004+130 and constitute the highest spectral quality X-ray observations of a radio-loud BAL quas

Greg Aldering, Alex G. Kim, Marek Kowalski, Eric V. Linder

We examine the utility of very high redshift Type Ia supernovae for cosmology and systematic uncertainty control. Next generation space surveys such as the Supernova/Acceleration Probe (SNAP) will obtain thousands of supernovae at z>1.7, beyond the design redshift for which the supernovae will be exquisitely characterized. We find that any z\gtrsim2 standard

Emma V. Ryan-Weber, Max Pettini, Piero Madau

We report the discovery of a strong CIV 1548,1550 absorption system at z_abs = 5.7238 in the near-infrared spectrum (J-band) of the z_em = 6.28 QSO SDSS J1030+0524. These observations, obtained with the Infrared Spectrometer And Array Camera (ISAAC) on the European Southern Observatory Very Large Telescope (ESO VLT), demonstrate that, with modern instrumenta

Paolo Padoan, Laurent Cambresy, Mika Juvela, Alexei Kritsuk

Maps of estimated dust column density in molecular clouds are usually assumed to reliably trace the total gas column density structure. In this work we present results showing a clear discrepancy between the dust and the gas distribution in the Taurus molecular cloud complex. We compute the power spectrum of a 2MASS extinction map of the Taurus region and fi

Andrew Fletcher, Anvar Shukurov

Narrow depolarized canals are common in maps of the polarized synchrotron emission of the Milky Way. Two physical effects that can produce these canals have been identified: the presence of Faraday rotation measure ($\RM$) gradients in a foreground screen and the cumulative cancellation of polarization known as differential Faraday rotation. We show that the

Daniel Bonneau, J. -M. Clausse, X. Delfosse, D. Mourard

In long baseline interferometry, the raw fringe contrast must be calibrated to obtain the true visibility and then those observables that can be interpreted in terms of astrophysical parameters. The selection of suitable calibration stars is crucial for obtaining the ultimate precision of interferometric instruments like the VLTI. We have developed software

Shin Watanabe, Masao Sako, Manabu Ishida, Yoshitaka Ishisaki

We present results from quantitative modeling and spectral analysis of the high mass X-ray binary Vela X-1 obtained with the Chandra HETGS. The spectra exhibit emission lines from H-like and He-like ions driven by photoionization, as well as fluorescent emission lines from several elements in lower charge states. In order to interpret and make full use of th

Mischa Schirmer, Thomas Erben, Marco Hetterscheidt, Peter Schneider

The aim of the present work is the construction of a mass-selected galaxy cluster sample based on weak gravitational lensing methods. This sample will be subject to spectroscopic follow-up observations. We apply the mass aperture statistics and a derivative of it to 19 square degrees of high quality, single colour wide field imaging data obtained with the WF

A. Cavaliere, A. Lapi

Shocks and blastwaves are expected to be driven driven into the intracluster medium filling galaxy groups and clusters by powerful outbursts of active galactic nuclei or quasars in the member galaxies; the first footprints of shock fronts have been tentatively traced out with X-ray imaging. We show how overpressures in the blasts behind the shock can prove t

L. F. Olsen, J. -M. Miralles, L. da Costa, R. Madejsky

This paper presents new J and Ks data obtained from observations conducted at the ESO 3.5m New Technology Telescope using the SOFI camera. These data were taken as part of the ESO Imaging Survey Deep Public Survey (DPS) and significantly extend the earlier optical/infrared EIS-DEEP survey presented in a previous paper. The DPS-IR survey comprises two observi

C. Clarke, D. Gittins

We study the response of the gaseous component of a galactic disc to the time dependent potential generated by N-body simulations of a spiral galaxy. The results show significant variation of the spiral structure of the gas which might be expected to result in significant fluctuations in the Star Formation Rate (SFR). Pronounced local variations of the SFR a

Hitoshi Miura, Taishi Nakamoto

Chondrules are considered to have much information on dust particles and processes in the solar nebula. It is naturally expected that protoplanetary disks observed in present star forming regions have similar dust particles and processes, so study of chondrule formation may provide us great information on the formation of the planetary systems. Evaporation d

Nils Ryde

Aims: In this paper we aim to study the chemical evolution of sulphur in the galactic disk, using a new optimal abundance indicator: the [SI] line at 10821 A. Similar to the optimal oxygen indicators, the [OI] lines, the [SI] line has the virtues of being less sensitive to the assumed temperatures of the stars investigated and of likely being less prone to n

Kaloyan Penev, Dimitar Sasselov, Frank Robinson, Pierre Demarque

The development of 2D and 3D simulations of solar convection has lead to a picture of convection quite unlike the usually assumed Kolmogorov spectrum turbulent flow. We investigate the impact of this changed structure on the dissipation properties of the convection zone, parametrized by an effective viscosity coefficient. We use an expansion treatment develo

Kozo Sadakane, Akira Arai, Wako Aoki, Nobuo Arimoto

We report on detailed spectroscopic studies performed for the secondary star in the black hole binary (micro-quasar) V4641 Sgr in order to examine its surface chemical composition and to see if its surface shows any signature of pollution by ejecta from a supernova explosion. High-resolution spectra of V4641 Sgr observed in the quiescent state in the blue-vi

A. H. Córsico, L. G. Althaus, M. M. Miller Bertolami

We reexamine the theoretical instability domain of pulsating PG1159 stars (GW Vir variables). We performed an extensive g-mode stability analysis on PG1159 evolutionary models with stellar masses ranging from 0.530 to 0.741 Mo for which the complete evolutionary stages of their progenitors from the ZAMS, through the thermally pulsing AGB and born-again phase

Gordon Petrie

The scale heights of stratification and the widths of steady solar coronal loops exhibit properties unexplained by standard theory: observed scale heights are often much greater than static theory predicts, while the nearly-constant widths of loop emission signatures defy theoretical expectations for large flux tubes in stratified media. In this work we rela

Patricia Sanchez-Blazquez, Reynier Peletier, Jorge Jimenez-Vicente, Nicolas Cardiel

A new stellar library developed for stellar population synthesis modeling is presented. The library consist of 985 stars spanning a large range in atmospheric parameters. The spectra were obtained at the 2.5m INT telescope and cover the range 3525-7500A at 2.3A (FWHM) spectral resolution. The spectral resolution, spectral type coverage, flux calibration accu

J. E. Dyson, J. M. Pittard, J. Meaburn, S. A. E. G. Falle

We have examined a stream-source model for the production of the cometary tails observed in the Helix Nebula NGC 7293 in which a transonic or moderately supersonic stream of ionized gas overruns a source of ionized gas. Hydrodynamic calculations reveal velocity structures which are in good agreement with the observational data on tail velocities and are cons

S. Y. Chang, V. R. Pandharipande

We present an analysis of the SU(3) symmetric model of the strongly interacting three component Fermi gas in the continuum space using quantum Monte Carlo techniques. Three body effects predominate in the regime of interaction strength beyond that of threshold of the three particle bound state. However, we find that there is an interval of the interaction st

Laszlo B. Kish

The possibility of a new type of computing, where thermal noise is the information carrier and the clock in a computer, is studied. The information channel capacity and the lower limit of energy requirement/dissipation are studied in a simple digital system with zero threshold voltage, for the case of error probability close to 0.5, when the thermal noise is

A. Burrows, D. Sudarsky, I. Hubeny

We have created a general methodology for calculating the wavelength-dependent light curves of close-in extrasolar giant planets (EGPs) as they traverse their orbits. Focussing on the transiting EGPs HD189733b, TrES-1, and HD209458b, we calculate planet/star flux ratios during secondary eclipse and compare them with the Spitzer data points obtained so far in

A. Bazán, M. Torres, G. Chiappe, E. Louis

The eigenfunctions of nested wells with incommensurate boundary geometry, in both hydrodynamic shallow water regime and quantum cases, are systematically and exhaustively studied in this letter. The boundary arrangement of the nested wells consist of polygonal ones, square or hexagonal, with a concentric immersed similar but rotated well or plateau. A rich t

Ravi Montenegro

This survey is an in-depth development of the theoretical aspects of the method of Evolving Sets, a method which has been used in several of my papers. It is fairly esoteric as to a large degree it stems from my efforts to ascertain whether Evolving sets is provably stronger than other isoperimetric methods (answer: yes, with qualifications). For an introduc

Brian W. O'Shea, Michael L. Norman

(abridged) We perform 12 extremely high resolution adaptive mesh refinement cosmological hydrodynamic simulations of Population III star formation in a Lambda CDM universe, varying the box size and large-scale structure, to understand systematic effects in the formation of primordial protostellar cores. We find results that are qualitatively similar to those

Y. D. Jho, X. Wang, J. Kono, D. H. Reitze

Cooperative spontaneous recombination (superfluorescence) of electron-hole plasmas in semiconductors has been a challenge to observe due to ultrafast decoherence. We argue that superfluorescence can be achieved in quantum-confined semiconductor systems and present experimental evidence for superfluorescence from high-density photoexcited electron-hole plasma

Johann Davidov, Oleg Mushkarov

The twistor method is applied for obtaining examples of generalized Kaehler structures which are not yielded by Kaehler structures.

Marcelo Samuel Berman

A combined BCDE (Brans-Dicke and Einstein-Cartan) theory with lambda-term is developed through Raychaudhuri's equation, for inflationary scenario. It involves a variable cosmological constant, which decreases with time, jointly with energy density, cosmic pressure, shear, vorticity, and Hubble's parameter, while the scale factor, total spin and scala

Ualbai Umirbaev

We prove that the well-known Anick automorphism of the free associative algebra F<x,y,z> over an arbitrary field F of characteristic 0 is wild.

Ualbai Umirbaev

We describe a set of defining relations of the tame automorphism group TA_3(F) of the polynomial algebra F[x_1,x_2,x_3] in variables x_1,x_2,x_3 over an arbitrary field F of characteristic 0.

J. Ocariz

We report measurements of time-dependent CP asymmetries related to the CKM angle $\beta/\phi_1$, using decays of neutral B mesons to charmonium, open charm and in $b\to s$ loop processes. A preliminary measurement of time-dependent CP asymmetries in $B^0\to \rho^0(770) K^0_S$ decays from the BaBar experiment is given here.

Florentin Smarandache, Jean Dezert

In this paper we propose a new family of Belief Conditioning Rules (BCRs) for belief revision. These rules are not directly related with the fusion of several sources of evidence but with the revision of a belief assignment available at a given time according to the new truth (i.e. conditioning constraint) one has about the space of solutions of the problem.

Hua-Shu Dou

In this paper, the physics of flow instability and turbulent transition in shear flows is studied by analyzing the energy variation of fluid particles under the interaction of base flow with a disturbance. For the first time, a model derived strictly from physics is proposed to show that the flow instability under finite amplitude disturbance leads to turbul

Joachim Ankerhold

Motivated by several experimental activities to detect charge noise produced by a mesoscopic conductor with a Josephson junction as on-chip detector, the switching rate out of its zero-voltage state is studied. This process is related to the fundamental problem of thermal escape in presence of non-Gaussian fluctuations. In the relevant case of weak higher th

Nakwoo Kim, Jeong-Hyuck Park

We classify the supersymmetric mass deformations of all the super Yang-Mills quantum mechanics, which are obtained by dimensional reductions of minimal super Yang-Mills in spacetime dimensions: ten, six, four, three and two. The resulting actions can be viewed as the matrix descriptions of supermembranes in nontrivial backgrounds of one higher dimensional su

M. Twitto, I. Sason

The performance of maximum-likelihood (ML) decoded binary linear block codes over the AWGN channel is addressed via the tangential-sphere bound (TSB) and two of its recent improved versions. The paper is focused on the derivation of the error exponents of these bounds. Although it was exemplified that some recent improvements of the TSB tighten this bound fo

Fizuli Mamedov

The origin of the fermion generations is discussed. A strong interactions spin $I_{S}$ is introduced which unifies the quarks and leptons as two multiplets of this spin. The electroweak vector bosons and gluons emerge as the fused states of these fermion multiplets.

Ulrich Mohrhoff

The physical motivation for the mathematical formalism of quantum mechanics is made clear and compelling by starting from an obvious fact - essentially, the stability of matter - and inquiring into its preconditions: what does it take to make this fact possible?

Xue-Qian Li, Xiang Liu, Yu-Ming Wang

The branching ratio of $B^-\to h_c+K^-$ is re-evaluated in the PQCD approach. In this theoretical framework all the phenomenological parameters in the wavefunctions and Sudakov factor are priori fixed by fitting other experimental data, and in the whole numerical computations we do not introduce any new parameter. Our results are consistent with the upper bo

G. G. Lapaire, J. E. Sipe

We present a general theory to describe two-photon interference, including a formal description of few photon intereference in terms of single-photon amplitudes. With this formalism, it is possible to describe both frequency entangled and separable two-photon interference in terms of single-photon wave functions. Using this description, we address issues rel

T. Gopinath, Anil Kumar

Geometric phases have been used in NMR, to implement controlled phase shift gates for quantum information processing, only in weakly coupled systems in which the individual spins can be identified as qubits. In this work, we implement controlled phase shift gates in strongly coupled systems, by using non-adiabatic geometric phases, obtained by evolving the m

Peter Hommelhoff, Catherine Kealhofer, Mark A. Kasevich

We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8 femtosecond low power laser pulses. This process is non-linear in the laser electric field, and the non-linearity can be tuned via the DC voltage applied to the tip. Numerical simulations of this system show that electron emission takes place with

Alberto Lencina, Beatriz Ruiz, Pablo Vaveliuk

This paper uses an alternative approach to study the monochromatic plane wave propagation within dielectric and conductor linear media of plane-parallel-faces. This approach introduces the time-averaged Poynting vector modulus as field variable. The conceptual implications of this formalism are that the nonequivalence between the time-averaged Poynting vecto

Irina Yehorchenko

We present an approach for construction of functional bases of differential invariants for some infinite-dimensional algebras with coefficients of generating operators depending on arbitrary functions. An example for the infinite-dimensional Poincare-type algebra is given.

Jean Dolbeault, Maria J. Esteban, Michael Loss

In the Dirac operator framework we characterize and estimate the ground state energy of relativistic hydrogenic atoms in a constant magnetic field and describe the asymptotic regime corresponding to a large field strength using relativistic Landau levels. We also define and estimate a critical magnetic field beyond which stability is lost.

Carsten Schultz

We show Péter Csorba&#39;s conjecture that the graph homomorphism complex Hom(C_5,K_{n+2}) is homeomorphic to a Stiefel manifold, the space of unit tangent vectors to the n-dimensional sphere. For this a general tool is developed that allows to replace the complexes Hom(G, K_n) by smaller complexes that are homeomorphic to them whenever G is a graph for whic

Kourosh Nozari, Behnaz Fazlpour

Consider a proposed model of the universe with $\hbar$ much greater than its well-known value of $10^{-34} Js$. In this model universe, very large objects can show quantum behaviors. In a scenario with large extra dimensions, $\hbar$ can attains very large values depending on the dimensionality of spacetime. In this letter, we show that although conventional

Davide Gaiotto, Andrew Strominger, Xi Yin

The modified elliptic genus for an M5-brane wrapped on a four-cycle of a Calabi-Yau threefold encodes the degeneracies of an infinite set of BPS states in four dimensions. By holomorphy and modular invariance, it can be determined completely from the knowledge of a finite set of such BPS states. We show the feasibility of such a computation and determine the

Graciela Gelmini, Carlos E. Yaguna

If the energy density of the Universe before nucleosynthesis is dominated by a scalar field $ϕ$ that decays and reheats the plasma to a low reheating temperature $T_{RH}$, neutralinos may be warm dark matter particles. We study this possibility and derive the conditions on the production mechanism and on the supersymmetric spectrum for which it is viable. La

Pierpaolo Mastrolia

We report on a technique for evaluating finite unitarity cut for one-loop amplitudes in gauge theories, and discuss its application to the cut-constructible part of six-gluon amplitude in QCD.

J. B. Formiga, C. Romero

We discuss two effects predicted by the general theory of relativity in the context of Rindler accelerated observers: the gravitational spectral shift and the time delay of light. We show that these effects also appear in a Rindler frame in the absence of gravitational field, in accordance with the Einstein&#39;s equivalence principle.

Mariano Ceccato, Marius Marin, Kim Mens, Leon Moonen

Understanding a software system at source-code level requires understanding the different concerns that it addresses, which in turn requires a way to identify these concerns in the source code. Whereas some concerns are explicitly represented by program entities (like classes, methods and variables) and thus are easy to identify, crosscutting concerns are no

M. Twitto, I. Sason, S. Shamai

The performance of maximum-likelihood (ML) decoded binary linear block codes is addressed via the derivation of tightened upper bounds on their decoding error probability. The upper bounds on the block and bit error probabilities are valid for any memoryless, binary-input and output-symmetric communication channel, and their effectiveness is exemplified for

I. Sason, I. Goldenberg

This paper is focused on the performance analysis of binary linear block codes (or ensembles) whose transmission takes place over independent and memoryless parallel channels. New upper bounds on the maximum-likelihood (ML) decoding error probability are derived. These bounds are applied to various ensembles of turbo-like codes, focusing especially on repeat

Vicky Choi, Navin Goyal

Point pattern matching problems are of fundamental importance in various areas including computer vision and structural bioinformatics. In this paper, we study one of the more general problems, known as LCP (largest common point set problem): Let $\PP$ and $\QQ$ be two point sets in $\mathbb{R}^3$, and let $ε\geq 0$ be a tolerance parameter, the problem is t

R. Monaco, M. Aaroe, J. Myging, R. J. Rivers

It has been argued by Zurek and Kibble that the likelihood of producing defects in a continuous phase transition depends in a characteristic way on the quench rate. In this paper we discuss an improved experiment for measuring the Zurek-Kibble scaling exponent $σ$ for the production of fluxons in annular symmetric Josephson Tunnel Junctions. We find $σ\simeq

N. V. Antonov, A. A. Ignatieva

Critical behaviour of a fluid, subjected to strongly anisotropic turbulent mixing, is studied by means of the field theoretic renormalization group. As a simplified model, relaxational stochastic dynamics of a non-conserved scalar order parameter, coupled to a random velocity field with prescribed statistics, is considered. The velocity is taken Gaussian, wh

P. M. Pasinetti, F. Roma, J. L. Riccardo, A. J. Ramirez-Pastor

Monte Carlo simulations and finite-size scaling analysis have been carried out to study the critical behavior in a submonolayer lattice-gas of interacting monomers adsorbed on one-dimensional channels arranged in a triangular cross-sectional structure. The model mimics a nanoporous environment, where each nanotube or unit cell is represented by a one-dimensi

D. Semenov, D. Wiebe, Th. Henning

This is the first paper in a series where we study the influence of turbulent diffusion and advective transport on the chemical evolution of protoplanetary disks, using a 2D flared disk model and a 2D mixing gas-grain chemical code with surface reactions. A first interesting result concerns the abundance of gas-phase CO in the outer regions of protoplanetary

John Irwin, Marina Shmakova, Jay Anderson

The long exposure times of the HST Ultra-Deep Field plus the use of an empirically derived position-dependent PSF, have enabled us to measure a cardioid/displacement distortion map coefficient as well as improving upon the sextupole map coefficient. We confirmed that curved background galaxies are clumped on the same angular scale as found in the HST Deep Fi

Tryphon T. Georgiou

We present several natural notions of distance between spectral density functions of (discrete-time) random processes. They are motivated by certain filtering problems. First we quantify the degradation of performance of a predictor which is designed for a particular spectral density function and then it is used to predict the values of a random process havi

Joshua L. Davis, Finn Larsen, Ross O&#39;Connell, Diana Vaman

We study d=2 0A string theory perturbed by tachyon momentum modes in backgrounds with non-trivial tachyon condensate and Ramond-Ramond (RR) flux. In the matrix model description, we uncover a complexified Toda lattice hierarchy constrained by a pair of novel holomorphic string equations. We solve these constraints in the classical limit for general RR flux a

V. I. Kukulin, I. T. Obukhovsky, P. Grabmayr, Amand Faessler

A new model for short-range isoscalar currents in the deuteron and in the NN system is developed; it is based on the generation of an intermediate dibaryon which is the basic ingredient for the medium- and short-range NN interaction which was proposed recently by the present authors.This new current model can very well describe the experimental data for the

Bogdan Danila, Yong Yu, John A. Marsh, Kevin E. Bassler

We present a novel heuristic algorithm for routing optimization on complex networks. Previously proposed routing optimization algorithms aim at avoiding or reducing link overload. Our algorithm balances traffic on a network by minimizing the maximum node betweenness with as little path lengthening as possible, thus being useful in cases when networks are jam

Konstantin V. Getman, Eric D. Feigelson, Gordon Garmire, Patrick Broos

The IC 1396N cometary globule within the large nearby HII region IC 1396 has been observed with the ACIS detector on board the Chandra X-ray Observatory. We detect 117 X-ray sources, of which ~50-60 are likely members of the young open cluster Trumpler~37 dispersed throughout the HII region, and 25 are associated with young stars formed within the globule. S

Arvid Perego

We give a generalization of Gabriel&#39;s Theorem on coherent sheaves to the case of coherent twisted sheaves on a smooth variety X over a field k. We show that the category Coh(X,α) determines the scheme structure of X for αin the Brauer group of X, and that any equivalence between Coh(X,α) and Coh(Y,β) induces an isomorphism between X and Y. In conclusion