June 2006 arXiv papers — page 34

Justin R. David, Rajesh Gopakumar

The Schwinger representation gives a systematic procedure for recasting large N field theory amplitudes as integrals over closed string moduli space. This procedure has recently been applied to a class of free field four point functions by Aharony, Komargodski and Razamat, to study the leading terms in the putative worldsheet OPE. Here we observe that the di

H. Ahmedov, I. H. Duru

New Casimir energy results for massless scalar field in some 3 -dimensional cavities are presented. We attempted to discuss the correlation between the sign and the magnitude of the energy and the shape of the cavities.

A. Gorsky

In this note we consider the spontaneous creation of the brane world in five-dimensional space with nondynamical external four-form field via spherically asymmetric bounce solution. We argue that spherically asymmetric bounce suggests several inequivalent directions of the time arrow upon the analytic continuation to the space-time with Lorentzian signature.

I. Ya. Aref'eva, R. Gorbachev, P. B. Medvedev, D. V. Rychkov

We reexamine the oscillator level truncation method in the bosonic String Field Theory (SFT) by calculation the descent relation <V_3|V_1>=Z_3<V_2|. For the ghost sector we use the fermionic vertices in the standard oscillator basis. We propose two new schemes for calculations. In the first one we assume that the insertion satisfies the overlap equation for

Steven Weinstein

Anthropic arguments in multiverse cosmology and string theory rely on the weak anthropic principle (WAP). We show that the principle, though ultimately a tautology, is nevertheless ambiguous. It can be reformulated in one of two unambiguous ways, which we refer to as WAP_1 and WAP_2. We show that WAP_2, the version most commonly used in anthropic reasoning,

Debajyoti Choudhury, Anindya Datta

The favoured resolution of the atmospheric neutrino anomaly involves an oscillation of the muon neutrino to a different state. Current experiments allow for the latter to contain a significantly large fraction of a non-standard flavour. We demonstrate how the next generation of experiments may take advantage of matter effects to resolve this issue.

C. Hendlmeier, M. Stratmann, A. Schafer

We present a detailed phenomenological study of photoproduction of two hadrons, both with high transverse momentum, in longitudinally polarized lepton-nucleon collisions. We consistently include ``direct&#39;&#39; and ``resolved&#39;&#39; photon contributions and examine the sensitivity of the relevant spin asymmetries to the gluon polarization in the nucleo

Robert Harlander

Recent theoretical developments concerning Higgs production at the Large Hadron Collider are reviewed, both in the Standard Model and in the MSSM. Emphasis is put on the inclusive and exclusive cross sections for gluon fusion, as well as on the associated production with bottom quarks.

Cai-Dian Lu

The small longitudinal polarization fractions (50%) of $B \to ϕK^*$ measured by B factories contradict with the naive theoretical counting rules. We review the current theoretical status of the $B\to VV$ decay studies and calculate many of them in the perturbative QCD factorization approach based on $k_T$ factorization. We find that the penguin annihilation

Xuelei Wang, Jihong Chen, Yaobei Liu, Suzhen Liu

The littlest Higgs model is the most economical little Higgs model. The observation of the new gauge bosons predicted by the littlest Higgs model could serve as a robust signature of the model. The ILC, with the high energy and luminosity, can open an ideal window to probe these new gauge bosons, specially, the lightest $B_H$. In the framework of the littles

N. Kochelev

We calculate the soft contribution to high energy quark-quark scattering that arises from an instanton-induced quark anomalous chromomagnetic moment. We demonstrate that this is a large contribution, which cannot be neglected for transverse momenta of a few GeV. We discuss the influence of this effect on inclusive particle production.

J. Greensite, A. V. Kovalenko, S. Olejnik, M. I. Polikarpov

We study the spectrum of low-lying eigenmodes of the kinetic operator for scalar particles, in the color adjoint representation of Yang-Mills theory. The kinetic operator is the covariant Laplacian, plus a constant which serves to renormalize mass. In the pure gauge theory, our data indicates that the interval between the lowest eigenvalue and the mobility e

D0 Collaboration, V. M. Abazov

We have searched for a heavy resonance decaying into a Z+jet final state in p-pbar collisions at a center of mass energy of 1.96 TeV at the Fermilab Tevatron collider using the D0 detector. No indication for such a resonance was found in a data sample corresponding to an integrated luminosity of 370/pb. We set upper limits on the cross section times branchin

Alan Macdonald

The time-redshift relation of Carmeli et al. differs from that of the standard flat LambdaCDM model by more than 500 million years for 1 < z < 4.5.

Shripad Thite

Let S = <s_1, s_2, s_3, ..., s_n> be a given vector of n real numbers. The rank of a real z with respect to S is defined as the number of elements s_i in S such that s_i is less than or equal to z. We consider the following decision problem: determine whether the odd-numbered elements s_1, s_3, s_5, ... are precisely the elements of S whose rank with respect

M. H. van Emden, B. Moa

We analyse the axioms of Euclidean geometry according to standard object-oriented software development methodology. We find a perfect match: the main undefined concepts of the axioms translate to object classes. The result is a suite of C++ classes that efficiently supports the construction of complex geometric configurations. Although all computations are p

Sergei V. Fedorenko, Piter V. Trifonov

We propose an improved algorithm for finding roots of polynomials over finite fields. This makes possible significant speedup of the decoding process of Bose-Chaudhuri-Hocquenghem, Reed-Solomon, and some other error-correcting codes.

Guo-Jie Gao, Jerzy Blawzdziewicz, Corey S. O&#39;Hern

Relative frequencies of mechanically stable (MS) packings of frictionless bidisperse disks are studied numerically in small systems. The packings are created by successively compressing or decompressing a system of soft purely repulsive disks, followed by energy minimization, until only infinitesimal particle overlaps remain. For systems of up to 14 particle

D. M. Newns, C. C. Tsuei

Twenty years of extensive research has yet to produce a general consensus on the origin of high temperature superconductivity (HTS). However, several generic characteristics of the cuprate superconductors have emerged as the essential ingredients of and/or constraints on any viable microscopic model of HTS. Besides a Tc of order 100K, the most prominent on t

T. A. Abtew, D. A. Drabold

We use accurate first principles methods to study the network dynamics of hydrogenated amorphous silicon, including the motion of hydrogen. In addition to studies of atomic dynamics in the electronic ground state, we also adopt a simple procedure to track the H dynamics in light-excited states. Consistent with recent experiments and computer simulations, we

Joerg Reichardt, Stefan Bornholdt

Study of the cluster- or community structure of complex networks makes an important contribution to the understanding of networks at a functional level. Despite the many efforts, no definition of community has been agreed on and important aspects such as the statistical significance and theoretical limits of community detection are not well understood. We sh

J. B. Staunton, L. Szunyogh, A. Buruzs, B. L. Gyorffy

We present a first-principles theory of the variation of magnetic anisotropy, K, with temperature, T, in metallic ferromagnets. It is based on relativistic electronic structure theory and calculation of magnetic torque. Thermally induced `local moment&#39; magnetic fluctuations are described within the relativistic generalisation of the `disordered local mom

Leonhard Mayrhofer, Milena Grifoni

A low energy-theory for non-linear transport in finite-size single-wall carbon nanotubes, based on a microscopic model for the interacting pz electrons and successive bosonization, is presented. Due to the multiple degeneracy of the energy spectrum diagonal as well as off-diagonal (coherences) elements of the reduced density matrix contribute to the nonlinea

J. Bravo-Abad, M. Ibanescu, J. D. Joannopoulos, M. Soljacic

We propose an on-chip optical waveguide for Bose-Einstein condensates based on the evanescent light fields created by surface states of a photonic crystal. It is shown that the modal properties of these surface states can be tailored to confine the condensate at distances from the chip surface significantly longer that those that can be reached by using conv

Peter Schwab, Michael Dzierzawa, Cosimo Gorini, Roberto Raimondi

How does an initially homogeneous spin-polarization in a confined two-dimensional electron gas with Rashba spin-orbit coupling evolve in time? How does the relaxation time depend on system size? We study these questions for systems of a size that is much larger than the Fermi wavelength, but comparable and even shorter than the spin relaxation length. Depend

C. Iniotakis

Andreev bound states at boundaries of d-wave superconductors are strongly influenced by the boundary geometry itself. In this work, the zero-energy spectral weight of the local quasiparticle density of states is presented for the case of wedge-shaped boundaries with rounded corners. Generally, both orientation of the d-wave and the specific local reflection

Ivan Brovchenko, Alla Oleinikova

Effect of confinement on the liquid-liquid transition of water are studied by simulations in the Gibbs ensemble. Upon cooling along the liquid-vapor coexistence curve, confined water undergoes transition from normal to strongly tetrahedral water via a first order phase transition (as in the bulk) or in a continuous way in dependence on pore hydrophilicity. I

Carlos P. Herrero

Solid helium (3He and 4He) in the hcp and fcc phases has been studied by path-integral Monte Carlo. Simulations were carried out in the isothermal-isobaric (NPT) ensemble at pressures up to 52 GPa. This allows one to study the temperature and pressure dependences of isotopic effects on the crystal volume and vibrational energy in a wide parameter range. The

A. V. Balatsky, M. J. Graf, Z. Nussinov, S. A. Trugman

Solid He4 is viewed as a nearly perfect Debye solid. Yet, recent calorimetry indicates that its low-temperature specific heat has both cubic and linear contributions. These features appear in the same temperature range ($T \sim 200$ mK) where measurements of the torsional oscillator period suggest a supersolid transition. We analyze the specific heat to comp

L. Tessieri, F. M. Izrailev

We introduce a new approach to analyse the global structure of electronic states in quasi-1D models in terms of the dynamics of a system of parametric oscillators with time-dependent stochastic couplings. We thus extend to quasi-1D models the method previously applied to 1D disordered models. Using this approach, we show that a ``delocalisation transition&#3

L. Tassini, F. Venturini, Q. -M. Zhang, R. Hackl

Inelastic light-scattering spectra of underdoped ${\rm La_{2-x}Sr_xCuO_4}$ (LSCO) single crystals are presented which provide direct evidence of the formation of quasi one-dimensional charged structures in the two-dimensional $\rm CuO_2$ planes. The ``stripes&#39;&#39; manifest themselves in a Drude-like peak at low energies and temperatures. The selection r

Robert J. Thacker, Evan Scannapieco, H. M. P. Couchman

(Abridged) We explore the idea that the anti-hierarchical turn-off observed in the quasar population arises from self-regulating feedback, via an outflow mechanism. Using a detailed hydrodynamic simulation we calculate the luminosity function of quasars down to a redshift of z=1 in a large, cosmologically representative volume. Outflows are included explicit

Glenn Schneider, Murray D. Silverstone, Dean C. Hines, Jean-Charles Augereau

HST/NICMOS PSF-subtracted coronagraphic observations of HD 181327 have revealed the presence of a ring-like disk of circumstellar debris seen in 1.1 micron light scattered by the disk grains, surrounded by a di use outer region of lower surface brightness. The annular disk appears to be inclined by 31.7 +/- 1.6 deg from face on with the disk major axis PA at

Georgina V. Coldwell, Diego G. Lambas

We analyse the environment of low redshift, z < 0.2, SDSS quasars using the spectral and photometric information of galaxies from the Sloan Digital Sky Survey Third Data Release (SDSS-DR3). We compare quasar neighbourhoods with field and high density environments through an analysis on samples of typical galaxies and groups. We compute the surrounding surfac

M. Steinmetz, T. Zwitter, A. Siebert, F. G. Watson

We present the first data release of the Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities and stellar atmosphere parameters (temperature, metallicity, surface gravity) of up to one million stars using the 6dF multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO).

Adam S. Bolton, Leonidas A. Moustakas, Daniel Stern, Scott Burles

We report the discovery of a new Einstein cross at redshift z_S = 2.701 based on Lyman-alpha emission in a cruciform configuration around an SDSS luminous red galaxy (z_L = 0.331). The system was targeted as a possible lens based on an anomalous emission line in the SDSS spectrum. Imaging and spectroscopy from the W. M. Keck Observatory confirm the lensing n

G. Garcia-Segura, J. A. Lopez, W. Steffen, J. Meaburn

In this paper we explore the dynamics of ionization bounded planetary nebulae after the termination of the fast stellar wind. When the stellar wind becomes negligible, the hot, shocked bubble depressurizes and the thermal pressure of the photoionized region, at the inner edge of the swept-up shell, becomes dominant. At this stage the shell tends to fragment

David Eichler, Amir Levinson

It is noted that the Liang-Zhang correlation can be accounted for with the viewing angle interpretation proposed earlier. The Ghirlanda correlation, recently generalized by Nava et al (2006) to a wind profile, can be accounted for by the viewing angle interpretation accordingly generalized to a wind profile. Most of the scatter in the spectra and time-integr

Olivier Daigle, Claude Carignan, Sebastien Blais-Ouellette

Thorough numerical simulations were run to test the performance of three processing methods of the data coming out from an electron multiplying charge coupled device (EMCCD), or low light level charge coupled device (L3CCD), operated at high gain, under real operating conditions. The effect of read-out noise and spurious charges is tested under various low f

Steve B. Howell, Carolyn Brinkworth, D. W. Hoard, Stefanie Wachter

We present the first observations of magnetic cataclysmic variables with the Spitzer Space Telescope. We used the Infrared Array Camera to obtain photometry of the polars EF Eri, GG Leo, V347 Pav, and RX J0154.0-5947 at 3.6, 4.5, 5.8, and 8.0 $μ$m. In all of our targets, we detect excess mid-infrared emission over that expected from the component stars alone

L. M. Dray

It is commonly assumed that high mass X-ray binary (HMXB) populations are little-affected by metallicity. However, the massive stars making up their progenitor systems depend on metallicity in a number of ways, not least through their winds. We present simulations, well-matched to the observed sample of Galactic HMXBs, which demonstrate that both the number

M. Lopez-Caniego, D. Herranz, J. Gonzalez-Nuevo, J. L. Sanz

We study the detection of extragalactic point sources in two-dimensional flat simulations for all the frequencies of the forthcoming ESA&#39;s Planck mission. In this work we have used the most recent available templates of the microwave sky: as for the diffuse Galactic components and the Sunyaev-Zel&#39;dovich clusters we have used the ``Plank Reference Sky

Andrei P. Lobanov

Nuclear activity in galaxies is closely connected to galactic mergers and supermassive black holes (SBH). Galactic mergers perturb substantially the dynamics of gas and stellar population in the merging galaxies, and they are expected to lead to formation of supermassive binary black holes (BBH) in the center of mass of the galaxies merged. A scheme is propo

M. Sereno, Ph. Jetzer

Dark matter or modifications of the Newtonian inverse-square law in the solar-system are studied with accurate planetary astrometric data. From extra-perihelion precession and possible changes in the third Kepler&#39;s law, we get an upper limit on the local dark matter density, rho_{DM} < 3*10^{-16} kg/m^3 at the 2-sigma confidence level. Variations in the

Igor V. Igumenshchev

Spherical (nonrotating) accretion flows with small-scale magnetic fields have been investigated using three-dimensional, time-dependent MHD simulations. These simulations have been designed to model high-resolution (quasi) steady accretion flows in a wedge computational domain that represents a small fraction of the full spherical domain. Subsonic and supers

N. Zacharias, U. Laux, A. Rakich, H. Epps

The U.S. Naval Observatory Robotic Astrometric Telescope (URAT) project aims at a highly accurate (5 mas), ground-based, all-sky survey. Requirements are presented for the optics and telescope for this 0.85 m aperture, 4.5 degree diameter field-of-view, specialized instrument, which are close to the capability of the industry. The history of the design proce

J. S. Dunlop, M. Cirasuolo, R. J. McLure

Motivated by the claimed discovery of a very massive galaxy (HUDF-JD2; M~5x10^11 Msun) at extreme redshift (z = 6.5) within the Hubble Ultra Deep Field (HUDF) (Mobasher et al. 2005), we have completed a systematic search for comparably massive galaxies with z > 4 among the 2688 galaxies in our K < 23.5 (AB) catalogue within the CDFS/GOODS-South field. This s

P. Popesso, A. Biviano, H. Böhringer, M. Romaniello

In this paper we consider a large sample of optically selected clusters, in order to elucidate the physical reasons for the existence of X-ray underluminous clusters. For this purpose we analyze the correlations of the X-ray and optical properties of a sample of 137 spectroscopically confirmed Abell clusters in the SDSS database. We search for the X-ray coun

Gianpiero Mangano, Alessandro Melchiorri, Paolo Serra, Asantha Cooray

We investigate the cosmological effects of a neutrino interaction with cold dark matter. We postulate a neutrino that interacts with a ``neutrino interacting dark matter&#39;&#39; (NIDM) particle with an elastic-scattering cross section that either decreases with temperature as $T^2$ or remains constant with temperature. The neutrino--dark-matter interaction

Andrei P. Lobanov, J. Anton Zensus

Past years have brought an increasingly wider recognition of the ubiquity of relativistic outflows (jets) in galactic nuclei, which has turned jets into an effective tool for investigating the physics of nuclear regions in galaxies. A brief summary is given here of recent results from studies of jets and nuclear regions in several active galaxies with promin

S. De Rijcke, P. Buyle, J. Cannon, F. Walter

We observed the CO(3-2) emission of the emission-line regions HubbleI, HubbleV, HubbleX, Holmberg 18, and the stellar emission-line object S28 in NGC6822 with the ESO Atacama Pathfinder Experiment (APEX) 12m telescope as part of its science verification. The very low system temperature of 130-180K enabled us to achieve detections in 4 single pointings and in

Naofumi Ohnishi, Kei Kotake, Shoichi Yamada

We present the results of numerical experiments, in which we have investigated the influence of the inelastic neutrino-helium interactions on the standing accretion shock instability supposed to occur in the post-bounce supernova core. The axisymmetric hydrodynamical simulations of accretion flows through the standing accretion shock wave onto the protoneutr

A. Alonso-Herrero, G. H. Rieke, M. J. Rieke, L. Colina

We use HST NICMOS continuum and Pa-alpha observations to study the near-infrared and star-formation properties of a representative sample of 30 local (d ~ 35-75Mpc) luminous infrared galaxies (LIRGs, infrared 8-1000um luminosities of L_IR=11-11.9[Lsun]). The data provide spatial resolutions of 25-50pc and cover the central ~3.3-7.1kpc regions of these galaxi

C. Ledoux, P. Petitjean, J. P. U. Fynbo, P. Moller

We used our database of VLT-UVES quasar spectra to build up a sample of 70 Damped Lyman-alpha (DLA) or strong sub-DLA systems with total neutral hydrogen column densities of log N(HI)>20 and redshifts in the range 1.7<z_abs<4.3. For each of the systems, we measured in an homogeneous manner the metallicities relative to Solar, [X/H] (with X=Zn, or S or Si), a

Benjamin F. Lane, Alon Retter, Joshua A. Eisner, Robert R. Thompson

During the last two years we have used the Palomar Testbed Interferometer to observe several explosive variable stars, including V838 Monocerotis, V1663 Aquilae and recently RS Ophiuchi. We observed V838 Monocerotis approximately 34 months after its eruption, and were able to resolve the ejecta. Observations of V1663 Aql were obtained starting 9 days after p

Benjamin F. Lane, Matthew W. Muterspaugh, Michael Shao

One of the biggest challenges associated with a nulling interferometer-based approach to detecting extra-solar Earth-like planets comes from the extremely stringent requirements of pathlength, polarization and amplitude matching in the interferometer. To the extent that the light from multiple apertures are not matched in these properties, light will leak th

S. J. Curran, J. K. Webb

In this paper we investigate the possible reasons why HI 21-cm absorption in damped Lyman-alpha systems (DLAs) has only been detected at low redshift... We suggest that the lack of 21-cm absorption detections at high redshift arises from the fact that these DLAs are at similar angular diameter distances to the background quasars (i.e. the distance ratios are

M. M. Romanova, R. V. E. Lovelace

The bunching of giant planets at a distance of several stellar radii may be explained by the disruption of the inner part of the disk by the magnetosphere of the star during the T Tauri stage of evolution. The rotating magnetic field of the star gives rise to a low density magnetospheric gap where stellar migration is strongly suppressed. We performed full 3

Hasan Yuksel, Shin&#39;ichiro Ando, John Beacom

The time-integrated luminosity and average energy of the neutrino emission spectrum are essential diagnostics of core-collapse supernovae. The SN 1987A electron antineutrino observations by the Kamiokande-II and IMB detectors are only roughly consistent with each other and theory. Using new measurements of the star formation rate history, we reinterpret the

Jogesh C. Pati

In the first part of the talk, I explain what empirical evidence points to the need for having an effective grand unification-like symmetry possessing the symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive theory including gravity--be it string/M theory or a reincarnation--this evidence then suggests that such a theory should lead

Alberto Escalante

Using basic ideas of simplectic geometry, we find the covariant canonically conjugate variables, the commutation relations and the Poincaré charges for chiral superconducting membranes (with null currents), as well as we find the stress tensor for the theory under study.

Leonardo Ermann, Marcos Saraceno

We present a broad family of quantum baker maps that generalize the proposal of Schack and Caves to any even Hilbert space with arbitrary boundary conditions. We identify a structure, common to all maps consisting of a simple kernel perturbed by diffraction effects. This &#34;essential&#34; baker&#39;s map has a different semiclassical limit and can be diago

R. Cartas-Fuentevilla, J. M. Solano-Altamirano

From the perspective of topological field theory we explore the physics beyond instantons. We propose the fluctons as nonperturbative topological fluctuations of vacuum, from which the self-dual domain of instantons is attained as a particular case. Invoking the Atiyah-Singer index theorem, we determine the dimension of the corresponding flucton moduli space

Mark P. J. L. Chang, Carlos O. Font, G. Charmaine Gilbreath, Eun Oh

In the infrared and visible bandpass, optical propagation theory conventionally assumes that humidity does not contribute to the effects of atmospheric turbulence on optical beams. While this assumption may be reasonable for dry locations, we demonstrate in this paper that there is an unequivocal effect due to the pre sence of humidity upon the strength of t

Liang Qiao, Radek Erban, C. T. Kelley, Ioannis G. Kevrekidis

Spatially distributed problems are often approximately modelled in terms of partial differential equations (PDEs) for appropriate coarse-grained quantities (e.g. concentrations). The derivation of accurate such PDEs starting from finer scale, atomistic models, and using suitable averaging, is often a challenging task; approximate PDEs are typically obtained

David Savitt

For every polynomial f of degree n with no double roots, there is an associated family C(f) of harmonic algebraic curves, fibred over the circle, with at most n-1 singular fibres. We study the combinatorial topology of C(f) in the generic case when there are exactly n-1 singular fibres. In this case, the topology of C(f) is determined by the data of an n-tup

Chao-Shang Huang, Tianjun Li, Chun Liu, Jonathan P. Shock

We embed the flipped SU(5) models into the SO(10) models. After the SO(10) gauge symmetry is broken down to the flipped SU(5) \times U(1)_X gauge symmetry, we can split the five/one-plets and ten-plets in the spinor \mathbf{16} and \mathbf{\bar{16}} Higgs fields via the stable sliding singlet mechanism. As in the flipped SU(5) models, these ten-plet Higgs fi

James D. Malley

The Bell-Kochen-Specker conditions (BKS) for a deterministic noncontextual hidden-variable model are wonderfully simple to state, deal with just one-dimensional projectors on a Hilbert space H and make no reference to a probabilistic phase space or quantum system. They only ask for an assignment of zero or one to every projector such that the assignment resp

R. Gianvittorio, A. Restuccia, J. Stephany

In this paper we extend the bosonic $D$-brane action in D=10 obtained by duality from the D=11 membrane wrapped on $S^1$ to an SU(2) non abelian system. This system presents only first class constraints, whose algebra closes off-shell and generalizes the algebra of diffeomorphisms of the $D2$-brane to include non abelian symmetry generators. From the SU(2) $

Cristian S. Calude, Michael A. Stay

We introduce the zeta number, natural halting probability and natural complexity of a Turing machine and we relate them to Chaitin&#39;s Omega number, halting probability, and program-size complexity. A classification of Turing machines according to their zeta numbers is proposed: divergent, convergent and tuatara. We prove the existence of universal converg

Igor I. Smolyaninov

Here we demonstrate that photons launched into a specially designed metamaterial waveguide act as massive quasi-particles, which experience strong acceleration. Laser light propagating through such a waveguide may be used as a thermometer which would measure the Unruh temperature. Moreover, the metamaterial waveguide design may be approximated by a tapered o

Fabrício Casarejos, J. C. Fabris, S. V. B. Gonçalves, Jaime F. Villas da Rocha

A two-component fluid representing dark energy is studied. One of the components has a polytropic form, while the other has a barotropic form. Exact solutions are obtained and the cosmological parameters are constrained using supernova type Ia data. In general, an open universe is predicted. A big rip scenario is largely preferred, but the dispersion in the

Roman V. Buniy, Stephen D. H. Hsu, A. Zee

Attempts to derive the Born rule, either in the Many Worlds or Copenhagen interpretation, are unsatisfactory for systems with only a finite number of degrees of freedom. In the case of Many Worlds this is a serious problem, since its goal is to account for apparent collapse phenomena, including the Born rule for probabilities, assuming only unitary evolution

Inanc Adagideli, Gerrit E. W. Bauer, Bertrand I. Halperin

Detection of current-induced spin accumulation via ferromagnetic contacts is discussed. Onsager&#39;s relations forbid that in a two-probe configuration spins excited by currents in time-reversal symmetric systems can be detected by switching the magnetization of a ferromangetic detector contact. Nevertheless, current-induced spins can be transferred as a to

R. Auzzi, M. Shifman, A. Yung

We consider N=2 supersymmetric quantum electrodynamics (SQED) with 2 flavors, the Fayet--Iliopoulos parameter, and a mass term $β$ which breaks the extended supersymmetry down to N=1. The bulk theory has two vacua; at $β=0$ the BPS-saturated domain wall interpolating between them has a moduli space parameterized by a U(1) phase $σ$ which can be promoted to a

Igor F. Herbut

The low-energy theory of interacting electrons on graphene&#39;s two-dimensional honeycomb lattice is derived and discussed. In particular, the Hubbard model in the large-N limit is shown to have a semi-metal - antiferromagnetic insulator quantum critical point in the universality class of the Gross-Neveu model. The same equivalence is conjectured to hold in

Pierre Hosteins, Stephane Lavignac, Carlos A. Savoy

In many extensions of the Standard Model, including a broad class of left-right symmetric and Grand Unified theories, the light neutrino mass matrix is given by the left-right symmetric seesaw formula $M_ν= f v_L - \frac{v^2}{v_R} Y_νf^{-1} Y_ν$, in which the right-handed neutrino mass matrix and the $SU(2)_L$ triplet couplings are proportional to the same m

Ravi Montenegro

We show how the evolving set methodology of Morris and Peres can be used to show Cheeger inequalities for bounding the spectral gap of a finite Markov kernel. This leads to sharp versions of several previous Cheeger inequalities, including ones involving edge-expansion, vertex-expansion, and mixtures of both. A bound on the smallest eigenvalue also follows.

Justin J. Schaefer, Michael S. Brotherton, Zhaohui Shang, Michael D. Gregg

We have detected FIRST J101614.3+520916 with the XMM-Newton X-ray Observatory. FIRST J101614.3+520916, one of the most extreme radio-loud, broad absorption line (BAL) quasars so far discovered, is also a Fanaroff-Riley type II (FR II) radio source. We find that, compared to its estimated intrinsic X-ray flux, the observed X-rays are likely suppressed, and th

Kurt Jacobs, Pavel Lougovski

We describe a nano-electromechnical system that exhibits the &#34;retroactive&#34; quantum jumps discovered by Mabuchi and Wiseman [Phys. Rev. Lett. 81, 4620 (1998)]. This system consists of a Cooper-pair box coupled to a nano-mechanical resonator, in which the latter is continuously monitored by a single-electron transistor or quantum point-contact. Further

K. Ebrahimi-Fard, P. Leroux

Shuffle and quasi-shuffle products are well-known in the mathematics literature. They are intimately related to Loday&#39;s dendriform algebras, and were extensively used to give explicit constructions of free commutative Rota-Baxter algebras. In the literature there exist at least two other Rota-Baxter type algebras, namely, the Nijenhuis algebra and the so

A. G. Ramm

If $A_q(β, α, k)$ is the scattering amplitude, corresponding to a potential $q\in L^2(D)$, where $D\subset\R^3$ is a bounded domain, and $e^{ikα\cdot x}$ is the incident plane wave, then we call the radiation pattern the function $A(β):=A_q(β, α, k)$, where the unit vector $α$, the incident direction, is fixed, and $k>0$, the wavenumber, is fixed. It is show

Jun-ichi Inoue, Jun Ohkubo

We investigate equilibrium statistical properties of urn models with disorder. Two urn models are proposed; one belongs to the Ehrenfest class, and the other corresponds to the Monkey class. These models are introduced from the view point of the power-law behavior and randomness; it is clarified that quenched random parameters play an important role in gener

W. Hollik, A. Huettmann, B. A. Kniehl

The H1 Collaboration at the DESY electron-proton collider HERA has observed, in photoproduction and neutral-current deep-inelastic scattering, an unexpected excess of events with isolated leptons and missing transverse momentum, especially at large values of hadronic transverse momentum - a signature typical for single top-quark production. This observation

Fulvio Baldovin

We review recent results obtained for the dynamics of incipient chaos. These results suggest a common picture underlying the three universal routes to chaos displayed by the prototypical logistic and circle maps. Namely, the period doubling, intermittency, and quasiperiodicity routes. In these situations the dynamical behavior is exactly describable through

J. Albert et al.

In 2005 and 2006, the MAGIC telescope has observed very high energy gamma-ray emission from the distant BL Lac object PG 1553+113. The overall significance of the signal is 8.8 sigma for 18.8h observation time. The light curve shows no significant flux variations on a daily time-scale, the flux level during 2005 was, however, significantly higher compared to

F. Bigazzi, A. L. Cotrone

We study certain exclusive decays of high spin mesons into mesons in models of large N_c Yang-Mills with few flavors at strong coupling using string theory. The rate of the process is calculated by studying the splitting of a macroscopic string on the relevant dual gravity backgrounds. In the leading channel for the decay of heavy quarkonium into two open-he

Lewis Bowen

The classical prime geodesic theorem (PGT) gives an asymptotic formula (as $x$ tends to infinity) for the number of closed geodesics with length at most $x$ on a hyperbolic manifold $M$. Closed geodesics correspond to conjugacy classes of $π_1(M)=Γ$ where $Γ$ is a lattice in $G=SO(n,1)$. The theorem can be rephrased in the following format. Let $X(\Z,Γ)$ be

Thomas D. Cohen, Paul M. Hohler

In the limit of heavy quark masses going to infinity, a symmetry is known to emerge in QCD relating properties of hadrons with two heavy quarks to analogous states with one heavy anti-quark. A key question is whether the charm mass is heavy enough so that this symmetry is manifest in at least an approximate manner. The issue is crucial in attempting to under

M. K. Jones

The ratio of the proton&#39;s electric to magnetic form factor, G_E/G_M, can be extracted in elastic electron-proton scattering by measuring either cross sections, beam-target asymmetry or recoil polarization. Separate determinations of G_E/G_M by cross sections and recoil polarization observables disagree for Q^2 > 1 (GeV/c)^2. Measurement by a third techni

Parampreet Singh, Kevin Vandersloot, G. V. Vereshchagin

Non-perturbative quantum geometric effects in Loop Quantum Cosmology predict a $ρ^2$ modification to the Friedmann equation at high energies. The quadratic term is negative definite and can lead to generic bounces when the matter energy density becomes equal to a critical value of the order of the Planck density. The non-singular bounce is achieved for arbit

M. Pustilnik, E. G. Mishchenko, O. A. Starykh

Coulomb drag between two quantum wires is exponentially sensitive to the mismatch of their electronic densities. The application of a magnetic field can compensate this mismatch for electrons of opposite spin directions in different wires. The resulting enhanced momentum transfer leads to the conversion of the charge current in the active wire to the spin cu

Federico Mescia, Christopher Smith, Stephanie Trine

A systematic analysis of New Physics impacts on the rare decays KL to pi0 l+ l- is performed. Thanks to their different sensitivities to flavor-changing local effective interactions, these two modes could provide valuable information on the nature of the possible New Physics at play. In particular, a combined measurement of both modes could disentangle scala

Victor Barzykin, L. P. Gor&#39;kov

According to [M.A. Tanatar et al., Phys. Rev. Lett. 95, 067002 (2005)], in a multi-band d-wave superconductor CeCoIn5 electrons remain partially uncondensed. Interactions must induce superconducting order on all Fermi surfaces. We calculate specific heat and thermal conductivity in a two band model in presence of defects. Superconductivity originates on one

Klaus Fabricius, Barry M. McCoy

We compute the operator which creates the missing degenerate states in the algebraic Bethe ansatz of the 8 vertex model at roots of unity and relate it to the concept of an elliptic current operator. We find that in sharp contrast with the corresponding formalism in the six-vertex model at roots of unity the current operator is not nilpotent with the consequ

M. Hirsch, Ernest Ma, J. C. Romao, J. W. F. Valle

We study the stability of the Harrison-Perkins-Scott (HPS) mixing pattern, assumed to hold at some high energy scale, against supersymmetric radiative corrections. We work in the framework of a reference minimal supergravity model (mSUGRA) where supersymmetry breaking is universal and flavor-blind at unification. The radiative corrections considered include

Jörg Hennig, Gernot Neugebauer

We discuss inelastic collisions of two rotating disks by using the conservation laws for baryonic mass and angular momentum. In particular, we formulate conditions for the formation of a new disk after the collision and calculate the total energy loss to obtain upper limits for the emitted gravitational energy.

J. Alfaro, A. Broncano, M. B. Gavela, S. Rigolin

Motivated by the electroweak hierarchy problem, we consider theories with two extra dimensions in which the four-dimensional scalar fields are components of gauge boson in full space. We explore the Nielsen-Olesen instability for SU(N) on a torus, in the presence of a magnetic background. A field theory approach is developed, computing explicitly the minimum

Xiuqing Huang

In a recent article [Science 317, 1705 (2007)], Anderson pointed out that many theories about electron pairing in cuprate superconductors may be on the wrong track and there is no reason to believe that the dynamic screening (k-space) can provide a valid glue to hold the electron pairs together. On the other hand, the most recent experimental observations im

Steen H. Hansen, Oscar Agertz, Michael Joyce, Joachim Stadel

N-body simulations sample their initial conditions on an initial particle distribution, which for cosmological simulations is usually a glass or grid, whilst a Poisson distribution is used for galaxy models, spherical collapse etc. These pre-initial conditions have inherent correlations, noise due to discreteness and preferential alignments, whilst the glass