June 2007 arXiv papers — page 22

J. Blümlein, B. Geyer, D. Robaschik

We describe the twist-2 contributions to inclusive unpolarized and polarized deep-inelastic diffractive scattering in an operator approach. The representation refers to the observed large rapidity gap but does not require reference to a pomeron picture. We discuss both the case of vanishing target mass $M$ and momentum transfer $t$ as well as the effects at

Andrzej M. Oles, Peter Horsch, Giniyat Khaliullin

Spin-orbital entanglement in the ground state of a one-dimensional SU(2)$\otimes$SU(2) spin-orbital model is analyzed using exact diagonalization of finite chains. For $S=1/2$ spins and $T=1/2$ pseudospins one finds that the quantum entanglement is similar at the SU(4) symmetry point and in the spin-orbital valence bond state. We also show that quantum trans

Andrzej M. Oles, Peter Horsch, Giniyat Khaliullin

Starting from the Mott insulator picture for cubic vanadates, we derive and investigate the model of superexchange interactions between V$^{3+}$ ions, with nearly degenerate $t_{2g}$ orbitals occupied by two electrons each. The superexchange interactions are strongly frustrated and demonstrate a strong interrelation between possible types of magnetic and orb

Wei-Hao Bian, Yan-Mei Chen, Qu-Sheng Gu, Jin-Min Wang

Using the stellar population synthesis, we model the stellar contribution for a sample of 110 double-peaked broad-lines AGNs from the Sloan Digital Sky Survey (SDSS). The stellar velocity dispersions ($σ_*$) are obtained for 52 double-peaked AGNs with obvious stellar absorption features, ranging from 106 to 284 \kms. We also use multi-component profiles to f

Y. Dagan, R. L. Greene

We measure the resistivity and Hall angle of the electron-doped superconductor Pr_{2-x}Ce_xCuO_4 as a function of doping and temperature. The resistivity Rho_xx at temperatures 100K < T < 300K is mostly sensitive to the electrons. Its temperature behavior is doping independent over a wide doping range and even for non superconducting samples. On the other ha

A. Laeuchli, S. Dommange, B. Normand, F. Mila

We consider the effects of doping the S=3/2 kagome lattice with static, nonmagnetic impurities. By exact diagonalization calculations on small clusters we deduce the local spin correlations and magnetization distribution around a vacancy. As in the S=1/2 kagome lattice, in the vicinity of the impurity we find an extended region where the spin correlations ar

O. E. Raichev

Spin current of two-dimensional holes occupying the ground-state subband in an asymmetric quantum well and interacting with static disorder potential is calculated in the presence of a weak magnetic field H perpendicular to the well plane. Both spin-orbit coupling and Zeeman coupling are taken into account. It is shown that the applied electric field excites

C. A. Lutken, G. G. Ross

The transitions between neighbouring plateaux in the quantum Hall system are observed to follow anti-holomophic scaling with superuniversal scaling exponents, showing that the system contains an emergent sub-modular discrete symmetry and a holomorphic structure at low energies. We identify a class of effective scaling models consistent with this data, which

O. E. Raichev

Dynamic response of two-dimensional electron systems with spin-orbit interaction is studied theoretically on the basis of quantum kinetic equation, taking into account elastic scattering of electrons. The spin polarization and spin current induced by the applied electric field are calculated for the whole class of electron systems described by p-linear spin-

Yu. Vasylkiv, Yu. Nastishin, R. Vlokh

We present experimental evidence of the fact that lysozyme crystals, which are grown from their mother solution and exist in it, dissolve on heating above T=307 K. We argue that the anomaly in the light scattering recently observed at the temperature T=307 K and identified in the reference [Svanidze A. V. et al. 2006. JETP Lett. 84: 551] as a structural crys

I. Yu. Martynyuk-Lototska, O. G. Mys, A. A. Grabar, I. M. Stoika

We have studied the acoustooptic (AO) diffraction in Sn2P2S6 crystals and found that they manifest high values of AO figure of merit. The above crystals may therefore be used as highly efficient materials in different AO applications.

Jalal Errami, Michel Peyrard, Nikos Theodorakopoulos

We report model calculations on DNA single strands which describe the equilibrium dynamics and kinetics of hairpin formation and melting. Modeling is at the level of single bases. Strand rigidity is described in terms of simple polymer models; alternative calculations performed using the freely rotating chain and the discrete Kratky-Porod models are reported

I. V. Tokatly, G. Vignale

We show that the Lorentz shear modulus -- one of the three elastic moduli of a homogeneous electron gas in a magnetic field -- can be calculated exactly in the limit of high magnetic field (i.e. in the lowest Landau level). Its value is $\pm \hbar n/4$, where $n$ is the two-dimensional electron density and the sign is determined by the orientation of the mag

Geoffrey Pearce

A transitive decomposition of a graph is a partition of the edge or arc set giving a set of subgraphs which are preserved and permuted transitively by a group of automorphisms of the graph. In this paper we give some background to the study of transitive decompositions and highlight a connection with partial linear spaces. We then describe a simple method fo

Marco Rahm, David Schurig, Daniel A. Roberts, Steven A. Cummer

The technique of applying form-invariant, spatial coordinate transformations of Maxwell&#39;s equations can facilitate the design of structures with unique electromagnetic or optical functionality. Here, we illustrate the transformation-optical approach in the designs of a square electromagnetic cloak and an omni-directional electromagnetic field concentrato

Chao-Yang Pang, Ben-Qiong Hu

Discrete Fourier transform (DFT) is the base of modern signal or information processing. 1-Dimensional fast Fourier transform (1D FFT) and 2D FFT have time complexity O(NlogN) and O(N^2logN) respectively. Quantum 1D and 2D DFT algorithms with classical output (1D QDFT and 2D QDFT) are presented in this paper. And quantum algorithm for convolution estimation

Johannes Blümlein

A brief summary is given on recent determinations of $Λ_{\rm QCD}$ and $α_s(M_Z^2)$ from deeply inelastic structure functions.

E. I. Duzzioni, R. M. Serra, M. H. Y. Moussa

Based only on the parallel transport condition, we present a general method to compute Abelian or non-Abelian geometric phases acquired by the basis states of pure or mixed density operators, which also holds for nonadiabatic and noncyclic evolution. Two interesting features of the non-Abelian geometric phase obtained by our method stand out: i) it is a gene

Sam Payne

We show that a conjecture of Einsiedler, Kapranov, and Lind on adelic amoebas of subvarieties of tori and their intersections with open halfspaces of complementary dimension is false for subvarieties of codimension greater than one that have degenerate projections to smaller dimensional tori. We prove a suitably modified version of the conjecture using algeb

Moira Chas

In the eighties Goldman discovered a Lie algebra structure on the vector space generated by the free homotopy classes of oriented curves on an oriented surface. The Lie bracket [a,b] is defined as the signed sum over the intersection points of a and b of the loop product of at the intersection points. If one of the classes has a simple representative we give

Bing He, Janos A. Bergou, Yuhang Ren

We propose an experimental setup that is capable of unambiguously discriminating any pair of linearly independent single photon polarization qubits, about which we don&#39;t have any knowledge except that an extra pair of these unknown states are provided as the reference. This setup, which is constructed with optical CNOT gates, weak cross Kerr non-linearit

Li-Gang Wang, Cheng-Liang Zhao

We investigate the dynamic evolution of the radiation forces produced by the pulsed Gaussian beams acting on a Rayleigh dielectric sphere. We derive the analytical expressions for the scattering force and all components of the ponderomotive force induced by the pulsed Gaussian beams. Our analysis shows that the radiation force, for both the transverse and lo

Helmut G. Katzgraber, D. Herisson, M. Oesth, Per Nordblad

We present experimental results attempting to fingerprint nonanalyticities in the magnetization curves of spin glasses found by Katzgraber et al. [Phys. Rev. Lett. 89, 257202 (2002)] via zero-temperature Monte Carlo simulations of the Edwards-Anderson Ising spin glass. Our results show that the singularities at zero temperature due to the reversal-field memo

Ching-Hwa Eu

The Hochschild homology/cohomology an associative algebra, together with the Connes differential, the contraction map and the Lie derivative, forms the structure of calculus. In this paper we compute explicitely the calculus structure of preprojective algebras of Dynkin quivers over a field of characteristic zero. This also completes the work in math.AG/0502

Goncalo Tabuada

Using the formalism of Grothendieck&#39;s derivators, we construct `the universal localizing invariant of dg categories&#39;. By this, we mean a morphism U_l from the pointed derivator associated with the Morita homotopy theory of dg categories to a triangulated strong derivator M^loc such that U_l commutes with filtered homotopy colimits, preserves the poin

Christian Corda

The aim of this paper is to show the gauge-invariance on the response of interferometers to gravitational waves (GWs). In this process, after a review of results on the Tranverse-Traceless (TT) gauge, where, in general, the theoretical computations on GWs are performed, which is due for completness, we analyse the gauge of the local observer, which represent

Wung-Hong Huang

The Wilson loop in the non-commutative dipole field theory is re-examined within the framework of dual gravity description. In contrast to the previous investigations, we let the dual string be moving along the deformed $S^5$ and find the exact expression of the interquark potential. The potential shows a Coulomb behavior at all distance and does not have a

R. W. Dunford, R. J. Holt

We reconsider parity violation experiments in atomic hydrogen and deuterium in the light of existing tests of the Electroweak interactions, and assess whether new experiments, using improved experimental techniques, could make useful contributions to testing the Standard Model (SM). We find that, if parity experiments in hydrogen can be done, they remain hig

Daijiro Suematsu

We propose a unified explanation for the origin of dark matter and baryon number asymmetry on the basis of a non-supersymmetric model for neutrino masses. Neutrino masses are generated in two distinct ways, that is, a tree-level seesaw mechanism with a single right-handed neutrino, and one-loop radiative effects by a new additional doublet scalar. A spontane

Israel Quiros

The hypothesis that the causal properties of space-time, as well as other properties of physical systems like unitarity, charge conservation, etc., might be decided by the higher dimensional structure (in particular, higher-dimensional physical laws), rather than by the four-dimensional one, is explored in order to evade the most awkward problems of higher-d

Charles Shapiro, Scott Dodelson

Two methods of constraining the properties of dark energy are weak lensing tomography and cluster counting. Uncertainties in mass calibration of clusters can be reduced by using the properties of halo clustering (the clustering of clusters). However, within a single survey, weak lensing and halo clustering probe the same density fluctuations. We explore the

Hrayr H. Matevosyan, Anthony W. Thomas, Peter C. Tandy

We extend recent studies of the effects of quark-gluon vertex dressing upon the solutions of the Dyson-Schwinger equation for the quark propagator. A momentum delta function is used to represent the dominant infrared strength of the effective gluon propagator so that the resulting integral equations become algebraic. The quark-gluon vertex is constructed fro

Souma Chaudhury, Seth Merkel, Tobias Herr, Andrew Silberfarb

We demonstrate quantum control of a large spin-angular momentum associated with the F=3 hyperfine ground state of 133Cs. A combination of time dependent magnetic fields and a static tensor light shift is used to implement near-optimal controls and map a fiducial state to a broad range of target states, with yields in the range 0.8-0.9. Squeezed states are pr

K. R. Davidson, L. W. Marcoux, H. Radjavi

We investigate algebraic and topological transitivity and, more generally, k-transitivity for linear spaces of operators. In finite dimensions, we determine minimal dimensions of k-transitive spaces for every k, and find relations between the degree of transitivity of a product or tensor product on the one hand and those of the factors on the other. We prese

K. R. Davidson, R. Levene, L. W. Marcoux, H. Radjavi

We provide a negative solution to a question of M. Rieffel who asked if the right and left topological stable ranks of a Banach algebra must always agree. Our example is found amongst a class of nest algebras. We show that for many other nest algebras, both the left and right topological stable ranks are infinite. We extend this latter result to Popescu&#39;

S. Mathis, J. -P. Zahn

We briefly recall the physical background of the transport of angular momentum and the mixing of chemicals inside stellar radiation zones and its importance for stellar evolution. Then, we describe its present modeling, its successes and its weaknesses. Next, we introduce the new theoretical developments that allow us to treat in a self-consistent way the ef

Kyoung Yee Kim, Hyung Won Lee, Yun Soo Myung

We investigate a model of brane cosmology to find a unified description of the radiation-matter-dark energy universe. It is of the interacting holographic dark energy with a bulk-holographic matter $χ$. This is a five-dimensional cold dark matter, which plays a role of radiation on the brane. Using the effective equations of state $ω^{\rm eff}_{\rm Λ}$ inste

J. Barzola-Quiquia, P. Esquinazi, M. Rothermel, D. Spemann

We have prepared magnetic graphite samples bombarded by protons at low temperatures and low fluences to attenuate the large thermal annealing produced during irradiation. An overall optimization of sample handling allowed us to find Curie temperatures $ T_c \gtrsim 350$ K at the used fluences. The magnetization versus temperature shows unequivocally a linear

Thomas Markwig

Very few examples of obstructed equsingular families of curves on surfaces other than the projective plane are known. Combining results from Westenberger and Hirano with an idea from math.AG/9802009 we give in the present paper series of examples of families of irreducible curves with simple singularities on surfaces in projective three-space which are not T

Thomas Keilen

In math.AG/0108089, math.AG/0212090 and math.AG/0308247 we gave numerical conditions which ensure that an equisingular family is irreducible respectively T-smooth. Combining results by Greuel, Lossen and Shustin and an idea from math.AG/9802009 we give in the present paper series of examples of families of irreducible curves on surfaces in projective three-s

James Allen Fill, Take Nakama

When algorithms for sorting and searching are applied to keys that are represented as bit strings, we can quantify the performance of the algorithms not only in terms of the number of key comparisons required by the algorithms but also in terms of the number of bit comparisons. Some of the standard sorting and searching algorithms have been analyzed with res

Li-Gang Wang

In this paper, we present a new model, hollow Gaussian-Schell model beams (HGSMBs), to describe the practical dark hollow beams. An analytical propagation formula for HGSMBs passing through a paraxial first-order optical system is derived based on the theory of coherence. Based on the derived formula, an application example showing the influence of spatial c

C. Palenzuela, L. Lehner, S. L. Liebling

We extend our previous studies of head-on collisions of boson stars by considering orbiting binary boson stars. We concentrate on equal mass binaries and study the dynamical behavior of boson/boson and boson/antiboson pairs. We examine the gravitational wave output of these binaries and compare with other compact binaries. Such a comparison lets us probe the

RadhaKrishna Ganti, Martin Haenggi

In the analysis of large random wireless networks, the underlying node distribution is almost ubiquitously assumed to be the homogeneous Poisson point process. In this paper, the node locations are assumed to form a Poisson clustered process on the plane. We derive the distributional properties of the interference and provide upper and lower bounds for its C

Adrian Riskin

We develop a quite elementary graph theoretic system for designing small-size augmented origami polyhedra out of Sonobé modules beginning with a (convex or not) deltahedron.

Adrian Riskin

We calculate the cordial edge deficiencies of the complete multipartite graphs and find an upper bound for their cordial vertex deficiencies. We also give conditions under which the tensor product of two cordial graphs is cordial.

Michael Gekhtman, Irina Nenciu

We study the Poisson structure associated to the defocusing Ablowitz-Ladik equation from a functional-analytical point of view, by reexpressing the Poisson bracket in terms of the associated Caratheodory function. Using this expression, we are able to introduce a family of compatible Poisson brackets which form a multi-Hamiltonian structure for the Ablowitz-

Johannes Blümlein, Sebastian Klein

Multiply nested finite harmonic sums $S_{a_1 ... a_n}(N)$ occur in many single scale higher order calculations in Quantum Field Theory. We discuss their algebraic and structural relations to weight {\sf w=6}. As an example, we consider the application of these relations to the soft and virtual corrections for Bhabha-scattering to $O(α^2)$.

F. Donado, J. L. Carrillo

The effect of periodic magnetic perturbations on the rheological properties of a low concentration magnetorheological dispersion is studied experimentally. It is found that an important increment in the measured viscosity occurs when in addition to a static field a magnetic periodic perturbation is applied. The magnitude of these changes depend on the amplit

L. Bardelli, M. Bini, P. G. Bizzeti, F. A. Danevich

The light output, $α/β$ ratio, and pulse shape have been investigated at $-25^\circ$ C with PbWO$_4$ crystal scintillators undoped, and doped by F, Eu, Mo, Gd and S. The fast $0.01-0.06 μ$s and middle $0.1-0.5 μ$s components of scintillation decay were observed for all the samples. Slow components of scintillation signal with the decay times $1-3 μ$s and $13

Bau-Sen Du

A simple method called symbolic representation for piecewise linear functions on the real line is introduced and used to compute the numbers of periodic points of all periods for some such functions. Since, for every positive integer m, the number of periodic points of minimal period m must be divisible by m, we obtain infinitely many congruence identities.

Monique Combescot, Odile Betbeder-Matibet, Roland Combescot

The non elementary-boson nature of excitons controls Bose-Einstein condensation in semiconductors. Composite excitons interact predominantly through Pauli exclusion; this produces dramatic couplings between bright and dark states. In microcavities, where bright excitons and photons form polaritons, they force the condensate to be linearly polarized--as obser

Adam Wasserman, Neepa T. Maitra, Eric J. Heller

Systems whose underlying classical dynamics are chaotic exhibit signatures of the chaos in their quantum mechanics. We investigate the possibility of using time-dependent density functional theory (TDDFT) to study the case when chaos is induced by electron-interaction alone. Nearest-neighbour level-spacing statistics are in principle exactly and directly acc

Yi Song, S. P. Banks, David Diaz

In this paper, we give an explicit construction of dynamical systems (defined within a solid torus) containing any knot (or link) and arbitrarily knotted chaos. The first is achieved by expressing the knots in terms of braids, defining a system containing the braids and extending periodically to obtain a system naturally defined on a torus and which contains

Emily S. C. Ching, Yue-Kin Tsang

Human heart rate is known to display complex fluctuations. Evidence of multifractality in heart rate fluctuations in healthy state has been reported [Ivanov et al., Nature {\bf 399}, 461 (1999)]. This multifractal character could be manifested as a dependence on scale or beat number of the probability density functions (PDFs) of the heart rate increments. On

R. Vlokh, O. Kvasnyuk

The Maxwell equations with accounting for tensors properties of time have been considered. The effects that follow from such consideration are described. These are the appearance of vacuum polarization, anisotropy of electromagnetic wave velocity in vacuum, anisotropy of the vacuum dielectric permittivity, rotation of light polarization plane, as well as the

Roberto Benzi, Emily S. C. Ching, Elisabetta De Angelis, Itamar Procaccia

Numerical simulations of turbulent channel flows, with or without additives, are limited in the extent of the Reynolds number \Re and Deborah number \De. The comparison of such simulations to theories of drag reduction, which are usually derived for asymptotically high \Re and \De, calls for some care. In this paper we present a study of drag reduction by ro

Hong-tao Bian, Yi Rao, Yan-yan Xu, An-an Liu

Unexpected spectral features are observed in the two photon spectrum of the pure water in the forward direction when an 80 femtosecond laser pulse is focused at 10^10Wcm-2 or less. Such intensity is much lower than the breakdown or stimulated threshold of the liquid water. The two broad features are about 2700cm-1 and 5000cm-1 red shifted from the hyper-Rayl

V. M. Kolomietz, S. Åberg, S. V. Radionov

The general problem of dissipation in macroscopic large-amplitude collective motion and its relation to energy diffusion of intrinsic degrees of freedom of a nucleus is studied. By applying the cranking approach to the nuclear many-body system, a set of coupled dynamical equations for the collective classical variable and the quantum mechanical occupancies o

Suresh Chandra

Propagation of Alfven waves in the solar plasma has been a topic of scientific interest for a long time. We have derived a dispersion relation for shear Alfven waves in a viscous and diffusive plasma.

A. Rod Gover, Josef Silhan

For commuting linear operators $P_0,P_1,..., P_\ell$ we describe a range of conditions which are weaker than invertibility. When any of these conditions hold we may study the composition $P=P_0P_1... P_\ell$ in terms of the component operators or combinations thereof. In particular the general inhomogeneous problem $Pu=f$ reduces to a system of simpler probl

Roberta Filippucci, Patrizia Pucci, Vicentiu Radulescu

Existence and non-existence results are established for quasilinear elliptic problems with nonlinear boundary conditions and lack of compactness. The proofs combine variational methods with the geometrical feature, due to the competition between the different growths of the non-linearities.

Qian Qian Shi, Sam Young Cho, Bo Li, Mun Dae Kim

Realizable spin models are investigated in a two superconducting flux qubit system. It is shown that a specific adjustment of system parameters in the two flux qubit system makes it possible to realize an artificial two-spin system that cannot be found naturally. For the artificial two-spin systems, time evolution of a prepared quantum state is discussed to

Yong-Seon Song, Hiranya Peiris, Wayne Hu

Models which accelerate the expansion of the universe through the addition of a function of the Ricci scalar f(R) leave a characteristic signature in the large-scale structure of the universe at the Compton wavelength scale of the extra scalar degree of freedom. We search for such a signature in current cosmological data sets: the WMAP cosmic microwave backg

Yi Song, Stephen P. Banks

In this paper, we will show that a periodic nonlinear, time-varying dissipative system that is defined on a genus-p surface contains one or more invariant sets which act as attractors. Moreover, we shall generalize a result in [Martins, 2004] and give conditions under which these invariant sets are not homeomorphic to a circle individually, which implies the

Vitaly Noskov

A study of the Model of Embedded Spaces (MES) with a relativistic version of Finslerian geometry is continued. The field equations of the MES (Einstein and Maxwell types) are derived, and this formally completes geometrization of classical electrodynamics. The minimal action principle leads to geometrization of the field sources (the right-hand sides of the

Zhidong Hao

We present a microscopic theory for superconductivity in a magnetic field based on a local approximation approach. We derive an expression for free energy density $F$ as a function of temperature $T$ and vector potential {\bf a}, and two basic equations of the theory: the first is an implicit solution for energy gap parameter amplitude $|Δ_{\bf k}|$ as a fun

Zhidong Hao

This paper concerns the solution of the self-consistency equation for energy gap parameter $Δ_{\bf k}$ in the BCS theory of superconductivity. We show that there exists a well-defined relation between the solution for energy gap parameter amplitude $|Δ_{\bf k}|$ for a general interaction $V_{{\bf k},{\bf k}&#39;}$ and energy gap $Δ$ obtained by using the cut

S. V. Lototsky, K. Stemmann

The paper studies stochastic integration with respect to Gaussian processes and fields. It is more convenient to work with a field than a process: by definition, a field is a collection of stochastic integrals for a class of deterministic integrands. The problem is then to extend the definition to random integrands. An orthogonal decomposition of chaos space

S. V. Lototsky, B. L. Rozovskii

A procedure is described for defining a generalized solution for stochastic differential equations using the Cameron-Martin version of the Wiener Chaos expansion. Existence and uniqueness of this Wiener Chaos solution is established for parabolic stochastic PDEs such that both the drift and the diffusion operators are of the second order.

Frank Simon

We present measurements of the double longitudinal spin asymmetries for inclusive pi0 and pi+(-) production in polarized p+p collisions at sqrt(s) = 200 GeV at mid-rapidity with the STAR detector from the 2005 RHIC run. These measurements are used to access Delta G/G, the gluon polarization in the proton. The observed unpolarized inclusive cross sections sho

N. Harrison, S. E. Sebastian, C. H. Mielke, A. Paris

We report measurements of the de Haas-van Alphen effect in CeIn3 in magnetic fields extending to ~90 T, well above the Ne&#39;el critical field of Hc ~61 T. The unreconstructed Fermi surface a-sheet is observed in the high magnetic field polarized paramagnetic limit, but with its effective mass and Fermi surface volume strongly reduced in size compared to th

Philip J. Harding, Tijmen G. Euser, Yoanna-Reine Nowicki-Bringuier, Jean-Michel Gerard

The authors study the ultrafast switching-on and -off of planar GaAs/AlAs microcavities. Up to 0.8% refractive index changes are achieved by optically exciting free carriers at 1720 nm and a pulse energy of 1.8 micro Joules. The cavity resonance is dynamically tracked by measuring reflectivity versus time delay with tunable laser pulses, and is found to shif

Rafe Jones, Jeremy Rouse

Given an abelian algebraic group $A$ over a global field $F$, $α\in A(F)$, and a prime $\ell$, the set of all preimages of $α$ under some iterate of $[\ell]$ generates an extension of $F$ that contains all $\ell$-power torsion points as well as a Kummer-type extension. We analyze the Galois group of this extension, and for several classes of $A$ we give a si

Jason W. Locasale

The utilization of multiple phosphorylation sites in regulating a biological response is ubiquitous in cell signaling. If each site contributes an additional, equivalent binding site, then one consequence of an increase in the number of phosphorylations may be to increase the probability that, upon disassociation, a ligand immediately rebinds to its receptor

F. A. Chishtie, Junji Jia, D. G. C. McKeon

The perturbative evaluation of the effective action can be expanded in powers of derivatives of the external field. We apply the renormalization group equation to the term in the effective action that is second order in the derivatives of the external field and all orders in a constant external field, considering both massless scalar $ϕ_4^4$ model and massle

Alejandro Ayala, J. Magnin, Luis Manuel Montano, Eduardo Rojas

We study the collisional energy loss mechanism for particles produced off mass-shell in a finite size QCD medium. The off mass-shell effects introduced are to consider particles produced in wave packets instead of plane waves and the length scale associated to an in-medium particles&#39; life-time. We show that these effects reduce the energy loss as compare

Richard S. Freedman, Mark S. Marley, Katharina Lodders

Opacities and chemical abundance data are crucial ingredients of ultracool dwarf and extrasolar giant planet atmosphere models. We report here on the detailed sources of molecular opacity data employed by our group for this application. We also present tables of Rosseland and Planck mean opacities which are of use in some studies of the atmospheres, interior

Daniel J. H. Chung, Lisa L. Everett, Kyoungchul Kong, Konstantin T. Matchev

If the cold dark matter consists of weakly interacting massive particles (WIMPs), anticipated measurements of the WIMP properties at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) will provide an unprecedented experimental probe of cosmology at temperatures of order 1 GeV. It is worth emphasizing that the expected outcome of thes

S. D. Brechet, M. P. Hobson, A. N. Lasenby

The Weyssenhoff fluid is a perfect fluid with spin where the spin of the matter fields is the source of torsion in an Einstein-Cartan framework. Obukhov and Korotky showed that this fluid can be described as an effective fluid with spin in general relativity. A dynamical analysis of such a fluid is performed in a gauge invariant manner using the 1+3 covarian

Oswaldo Dieguez, David Vanderbilt

We present a detailed study of the structural behavior and polarization reversal mechanism in phase III of KNO$_3$, an unusual ferroelectric material in which the nitrate groups rotate during polarization reversal. This material was one of several studied in a previous work [O. Di\'eguez and D. Vanderbilt, Phys. Rev. Lett. {\bf 96}, 056401 (2006)] where meth

Paulino R. Villas Boas, Francisco A. Rodrigues, Gonzalo Travieso, Luciano da F. Costa

Great part of the interest in complex networks has been motivated by the presence of structured, frequently non-uniform, connectivity. Because diverse connectivity patterns tend to result in distinct network dynamics, and also because they provide the means to identify and classify several types of complex networks, it becomes important to obtain meaningful

Arnab Sen, Kedar Damle, Ashvin Vishwanath

We study kagome lattice antiferromagnets where the effects of easy axis single-ion anisotropy ($D$) dominates over the Heisenberg exchange $J$. For $S \ge 3/2$, virtual quantum fluctuations help lift the extensive classical degeneracy. We demonstrate the presence of a one-third magnetization plateau for a broad range of magnetic fields $J^3/D^2 \lesssim B \l

Yuk Tung Liu, Stuart L. Shapiro, Branson C. Stephens

We perform axisymmetric simulations of the magnetorotational collapse of very massive stars in full general relativity. Our simulations are applicable to the collapse of supermassive stars (M > 10^3M_sun) and to very massive Pop III stars. We model our initial configurations by n=3 polytropes. The ratio of magnetic to rotational kinetic energy in these confi

S. Viola Kusminskiy, Johan Nilsson, D. K. Campbell, A. H. Castro Neto

We calculate the electronic compressibility arising from electron-electron interactions for a graphene bilayer within the Hartree-Fock approximation. We show that, due to the chiral nature of the particles in this system, the compressibility is rather different from those of either the two-dimensional electron gas or ordinary semiconductors. We find that an

Valeri N. Kotov, Bruno Uchoa, A. H. Castro Neto

We discuss the effect of electron-electron interactions on the static polarization properties of graphene beyond RPA. Divergent self-energy corrections are naturally absorbed into the renormalized coupling constant $α$. We find that the lowest order vertex correction, which is the first non-trivial correlation contribution, is finite, and about 30% of the RP

Gennaro Corcella, Giancarlo Ferrera

We use a recently proposed non-perturbative model, based on an effective strong coupling constant and free from tunable parameters, to study c-flavoured hadron production in e+e- annihilation. Charm-quark production is described in the framework of perturbative fragmentation functions, with NLO coefficient functions, NLL non-singlet DGLAP evolution and NNLL

Supratim Sengupta, Andrew D. Rutenberg

Ongoing sub-cellular oscillation of Min proteins is required to block minicelling in E. coli. Experimentally, Min oscillations are seen in newly divided cells and no minicells are produced. In model Min systems many daughter cells do not oscillate following septation because of unequal partitioning of Min proteins between the daughter cells. Using the 3D mod

Kari Enqvist, Lotta Mether, Sami Nurmi

We consider the supergravity origin of the recently proposed MSSM inflationary model, which relies on the existence of a saddle point along a dimension six flat direction. We derive the conditions that the Kahler potential has to satisfy for the saddle point to exist irrespective of the hidden sector vevs. We show that these conditions are satisfied by a sim

Christoph Luhn, Salah Nasri, Pierre Ramond

The Non-Abelian finite group PSL_2(7) is the only simple subgroup of SU(3) with a complex three-dimensional irreducible representation. It has two maximal subgroups, S_4 which, along with its own A_4 subgroup, has been successfully applied in numerous models of flavor, as well as the 21 element Frobenius group Z_7 x Z_3, which has gained much less attention.

Anthony Chefles

The standard oracle operator corresponding to a function f is a unitary operator that computes this function coherently, i.e. it maintains superpositions. This operator acts on a bipartite system, where the subsystems are the input and output registers. In distributed quantum computation, these subsystems may be spatially separated, in which case we will be

Rodica D. Costin

Nonlinear perturbation of Fuchsian systems are studied in regions including two singularities. Such systems are not necessarily analytically equivalent to their linear part (they are not linearizable). Nevertheless, it is shown that in the case when the linear part has commuting monodromy, and the eigenvalues have positive real parts, there exists a unique c

Rodica D. Costin

Nonlinear perturbation of Fuchsian systems are studied in a region including two singularities. It is proved that such systems are generally not analytically equivalent to their linear part (they are not linearizable) and the obstructions are found constructively, as a countable set of numbers. Furthermore, assuming a polynomial character of the nonlinear pa

Neelima Sehgal, John P. Hughes, David Wittman, Vera Margoniner

We compare X-ray and weak-lensing masses for four galaxy clusters that comprise the top-ranked shear-selected cluster system in the Deep Lens Survey. The weak-lensing observations of this system, which is associated with A781, are from the Kitt Peak Mayall 4-m telescope, and the X-ray observations are from both Chandra and XMM-Newton. For a faithful comparis

Lubomir Gavrilov, Jaume Gine, Maite Grau

Let W be a weight-homogeneous planar polynomial differential system with a center. We find an upper bound of the number of limit cycles which bifurcate from the period annulus of W under a generic polynomial perturbation. We apply this result to a particular family of planar polynomial systems having a nilpotent center without meromorphic first integral.

Ribhu K. Kaul, Yong Baek Kim, Subir Sachdev, T. Senthil

High temperature superconductivity emerges in the cuprate compounds upon changing the electron density of an insulator in which the electron spins are antiferromagnetically ordered. A key characteristic of the superconductor is that electrons can be extracted from them at zero energy only if their momenta take one of four specific values (the `nodal points&#

Y. Wiaux, P. Vielva, R. B. Barreiro, E. Martinez-Gonzalez

The decomposition of a signal on the sphere with the steerable wavelet constructed from the second Gaussian derivative gives access to the orientation, signed-intensity, and elongation of the signal&#39;s local features. In the present work, the non-Gaussianity of the WMAP temperature data of the cosmic microwave background (CMB) is analyzed in terms of the

Ioannis Contopoulos

We show that toroidal magnetic field annihilation in the equatorial current sheet of the pulsar magnetosphere is related to how fast poloidal magnetic field lines close as we move away from the light cylinder. This determines the reconnection radial electric field which directly accelerates particles in the neutral layer inside the equatorial current sheet.

Herbert W. Hamber, Ruth M. Williams

In a quantum theory of gravity the gravitational Wilson loop, defined as a suitable quantum average of a parallel transport operator around a large near-planar loop, provides important information about the large-scale curvature properties of the geometry. Here we shows that such properties can be systematically computed in the strong coupling limit of latti

Regis Blache, Eric Ferard, Hui June Zhu

Let P(x) be a one-variable Laurent polynomial of degree (d_1,d_2) over a finite field of characteristic p. For any fixed positive integer s not divisible by p, we prove that the (normalized) p-adic Newton polygon of the L-functions of exponential sums of P(x^s) has a tight lower bound which we call `Hodge-Stickelberger polygon&#39;, depending only on d_1,d_2