October 2005 arXiv papers — page 11

Michael Levitin, Leonid Parnovski, Iosif Polterovich

We construct a series of examples of planar isospectral domains with mixed Dirichlet-Neumann boundary conditions. This is a modification of a classical problem proposed by M. Kac.

Anthony L. Piro, Lars Bildsten

We calculate the photon energy dependence of the pulsed amplitude of neutron star (NS) surface modes. Simple approximations demonstrate that it depends most strongly on the bursting NS surface temperature. This result compares well with full integrations that include Doppler shifts from rotation and general relativistic corrections to photon propagation. We

Vyacheslav Krushkal

The notion of a Bing cell is introduced, and it is used to define invariants, link groups, of 4-manifolds. Bing cells combine some features of both surfaces and 4-dimensional handlebodies, and the link group λ(M) measures certain aspects of the handle structure of a 4-manifold M. This group is a quotient of the fundamental group, and examples of manifolds ar

Csaba Csaki, Guido Marandella, Yuri Shirman, Alessandro Strumia

Supersymmetry combined with little-Higgs can render the Higgs vev super-little, providing models of electroweak symmetry breaking free from fine-tunings. We discuss the difficulties that arise in implementing this idea and propose one simple successful model. Thanks to appropriately chosen Higgs representations, D-terms give no tree-level mass term to the Go

P. Faccioli, M. Sega, F. Pederiva, H. Orland

We present a method to investigate the kinetics of protein folding on a long time-scale and the dynamics underlying the formation of secondary and tertiary structures during the entire reaction. The approach is based on the formal analogy between thermal and quantum diffusion: by writing the solution of the Fokker-Planck equation for the time-evolution of a

Thomas H. Otway

A simple model for electromagnetic wave propagation through zero-temperature plasma is analyzed. Many of the complexities of the plasma state are present even under these idealized conditions, and a number of mathematical difficulties emerge. In particular, boundary value problems formulated on the basis of conventional electromagnetic theory turn out to be

Volker D. Burkert

The status of the search for pentaquark baryons is reviewed in light of new results from the first two dedicated experiments from CLAS at Jefferson Lab and of new analyses from several laboratories on the $Theta^+(1540)$. Evidence for and against two heavier pentaquark states is also discussed.

Stefano Ansoldi, Eduardo I. Guendelman, Euro Spallucci

The use of a non-Riemannian measure of integration in the action of strings and branes allows the possibility of dynamical tension. In particular, lower dimensional objects living in the string/brane can induce discontinuities in the tension: the effect of pair creation on the string tension is studied. We investigate then the role that these new features ca

V. N. Bolotov, E. N. Guschin, V. A. Duk, S. V. Laptev

Results of study of the radiative kaon decay K-->pi0 e nu gamma at ISTRA+ setup are presented. 4476 events of this decay have been observed. The branching ratio is measured.

Gleb Arutyunov, Sergey Frolov

We introduce a uniform light-cone gauge for strings propagating in AdS space-time. We use the gauge to analyze strings from the su(1|1) sector, and show that the reduced model is described by a quadratic action for two complex fermions. Thus, the uniform light-cone gauge allows us to solve the model exactly. We analyze the near BMN spectrum of states from th

D. V. Kolesnikov, V. A. Osipov

The low-energy electronic structure of icosahedral fullerenes is studied within the field-theory model. In the field model, the pentagonal rings in the fullerene are simulated by two kinds of gauge fields. The first one, non-abelian field, follows from so-called K spin rotation invariance for the spinor field while the second one describes the elastic flow d

J. Dukelsky, G. Ortiz, S. M. A. Rombouts, K. Van Houcke

We introduce an exactly-solvable model to study the competition between the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) and breached-pair superfluid in strongly interacting ultracold asymmetric Fermi gases. One can thus investigate homogeneous and inhomogeneous states on an equal footing and establish the quantum phase diagram. For certain values of the filling

L. Santos, T. Pfau

We analyze the physics of spin-3 Bose-Einstein condensates, and in particular the new physics expected in on-going experiments with condensates of Chromium atoms. We first discuss the ground-state properties, which, depending on still unknown Chromium parameters, and for low magnetic fields can present various types of phases. We also discuss the spinor-dyna

Manu Mathur

We solve the Gauss law as well as the corresponding Mandelstam constraints of (d+1) dimensional SU(2) lattice gauge theory in terms of harmonic oscillator prepotentials. This enables us to explicitly construct a complete orthonormal and manifestly gauge invariant basis in the physical Hilbert space. Further, we show that this gauge invariant description repr

G. Kofinas, G. Panotopoulos, T. N. Tomaras

The role of brane-bulk energy exchange and of an induced gravity term on a single braneworld of negative tension and vanishing effective cosmological constant is studied. It is shown that for the physically interesting cases of dust and radiation a unique global attractor which can realize our present universe (accelerating and 0<Omega_{m0}<1) exists for a w

Matthew D. Duez, Yuk Tung Liu, Stuart L. Shapiro, Masaru Shibata

Hypermassive neutron stars (HMNSs) -- equilibrium configurations supported against collapse by rapid differential rotation -- are possible transient remnants of binary neutron star mergers. Using newly developed codes for magnetohydrodynamic simulations in dynamical spacetimes, we are able to track the evolution of a magnetized HMNS in full general relativit

The CDF Collaboration

We present a search for top-antitop events with a tau lepton in the final state. The data sample corresponds to an integrated luminosity of 194/pb collected with the CDF II detector from proton-antiproton collisions at a center of mass energy of 1.96 TeV. We observe two events with an expected signal of 1.0+/-0.2 events and a background of 1.3+/-0.3 events.

Carlo Ottaviani, Stojan Rebic, David Vitali, Paolo Tombesi

The interaction of a five-level atomic system involving electromagnetically induced transparency with four light fields is investigated. Two different light-atom configurations are considered, and their efficiency in generating large nonlinear cross-phase shifts compared. The dispersive properties of those schemes are analyzed in detail, and the conditions l

Adam Burrows, Eli Livne, Luc Dessart, Christian Ott

We present a new mechanism for core-collapse supernova explosions that relies upon acoustic power generated in the inner core as the driver. In our simulation using an 11-solar-mass progenitor, a strong advective-acoustic oscillation a la Foglizzo with a period of ~25-30 milliseconds (ms) arises ~200 ms after bounce. Its growth saturates due to the generatio

Walter Bergweiler, Alexandre Eremenko

We prove Polya&#39;s conjecture of 1943: For a real entire function of order greater than 2, with finitely many non-real zeros, the number of non-real zeros of the n-th derivative tends to infinity with n. We use the saddle point method and potential theory, combined with the theory of analytic functions with positive imaginary part in the upper half-plane.

Francesca Ferlaino, Chiara D&#39;Errico, Giacomo Roati, Matteo Zaccanti

We perform extensive magnetic Feshbach spectroscopy of an ultracold mixture of fermionic 40K and bosonic 87Rb atoms. The magnetic-field locations of 14 interspecies resonances is used to construct a quantum collision model able to predict accurate collisional parameters for all K-Rb isotopic pairs. In particular we determine the interspecies s-wave singlet a

J. F. Perez-Azorin, J. A. Miralles, J. A. Pons

The thermal emission from isolated neutron stars is not well understood. The X-ray spectrum is very close to a blackbody but there is a systematic optical excess flux with respect to the extrapolation to low energy of the best blackbody fit. This fact, in combination with the observed pulsations in the X-ray flux, can be explained by anisotropies in the surf

John J. L. Morton, Alexei M. Tyryshkin, Arzhang Ardavan, Kyriakos Porfyrakis

We examine the temperature dependence of the relaxation times of the molecules N@C60 and N@C70 (which comprise atomic nitrogen trapped within a carbon cage) in liquid CS2 solution. The results are inconsistent with the fluctuating zero field splitting (ZFS) mechanism, which is commonly invoked to explain electron spin relaxation for S > 1/2 spins in liquid s

Nikolay Gromov, Vladimir Kazakov

We find explicit expressions for two first finite size corrections to the distribution of Bethe roots, the asymptotics of energy and high conserved charges in the sl(2) quantum Heisenberg spin chain of length J in the thermodynamical limit J->\infty for low energies E\sim 1/J. This limit was recently studied in the context of integrability in perturbative N=

Niko Jokela, Esko Keski-Vakkuri, Jaydeep Majumder

We study the tree level scattering or emission of n closed superstrings from a decaying non-BPS brane in Type II superstring theory. We attempt to calculate generic n-point superstring disk amplitudes in the rolling tachyon background. We show that these can be written as infinite power series of Toeplitz determinants, related to expectation values of a peri

Viorel Iftimie, Marius Mantoiu, Radu Purice

In previous papers, a generalization of the Weyl calculus was introduced in connection with the quantization of a particle moving in $\mathbb R^n$ under the influence of a variable magnetic field $B$. It incorporates phase factors defined by $B$ and reproduces the usual Weyl calculus for B=0. In the present article we develop the classical pseudodifferential

Ana Maria Rey, Guido Pupillo, J. V. Porto

We calculate entropy-temperature curves for interacting bosons in unit filled optical lattices for both homogeneous and harmonically trapped situations, and use them to understand how adiabatic changes in the lattice depth affect the temperature of the system. In a translationally invariant lattice, the zero tunneling limit facilitates a rather detailed anal

S. J. Brodsky, H. J. Pirner, J. Raufeisen

We analyze the scaling properties of inclusive hadron production in proton-proton and in heavy ion collisions from fixed target to collider energies. At large transverse momentum p_T, the invariant cross section exhibits a power-like behavior Ed^3σ/d^3p\propto p_T^{-n} at fixed transverse x, x_T=2p_T/\sqrt{s}, and fixed center-of-mass scattering angle θ_{cm}

A. V. Meremianin

The technique of vector differentiation is applied to the problem of the derivation of multipole expansions in four-dimensional space. Explicit expressions for the multipole expansion of the function $r^n C_j (\hr)$ with $\vvr=\vvr_1+\vvr_2$ are given in terms of tensor products of two hyperspherical harmonics depending on the unit vectors $\hr_1$ and $\hr_2

Marc Atlan, Hélyette Geman, Marc Yor

The rapidly growing hedge fund industry has provided individual and institutional investors with new investment vehicles and styles of management. It has also brought forward a new form of performance contract: hedge fund managers receive incentive fees which are typically a fraction of the fund net asset value (NAV) above its starting level - a rule known a

Petr Tretyakov, Aleksey Toporensky, Yuri Shtanov, Varun Sahni

We examine a class of braneworld models in which the expanding universe encounters a &#34;quiescent&#34; future singularity. At a quiescent singularity, the energy density and pressure of the cosmic fluid as well as the Hubble parameter remain finite while all derivatives of the Hubble parameter diverge (i.e., ${\dot H}$, ${\ddot H}$, etc. $\to \infty$). Sin

Gernot Schaller, Sarah Mostame, Ralf Schützhold

Most investigations devoted to the conditions for adiabatic quantum computing are based on the first-order correction ${\bra{Ψ_{\rm ground}(t)}\dot H(t)\ket{Ψ_{\rm excited}(t)} /ΔE^2(t)\ll1}$. However, it is demonstrated that this first-order correction does not yield a good estimate for the computational error. Therefore, a more general criterion is propose

R. Casadio, F. Finelli, M. Luzzi, G. Venturi

We extend the WKB method for the computation of cosmological perturbations during inflation beyond leading order and provide the power spectra of scalar and tensor perturbations to second order in the slow-roll parameters. Our method does not require that the slow-roll parameters be constant. Although leading and next-to-leading results in the slow-roll para

Chong Sheng Li, Shou-hua Zhu

In this talk, some important QCD effects in Higgs physics, supersymmetry and top physics, as well as the factorization and resummation techniques in QCD are reviewed.

A. Yamaguchi, K. Yano, H. Tanigawa, S. Kasai

We investigated the aspect ratio (thickness/width) dependence of the threshold current density required for the current-driven domain wall (DW) motion for the Ni81Fe19 nanowires. It has been shown theoretically that the threshold current density is proportional to the product of the hard-axis magnetic anisotropy Kperp and the DW width lamda. (Phys. Rev. Lett

Manuel Masip, Iacopo Mastromatteo

Models where supersymmetry (SUSY) is manifest only in a sector of the low-energy spectrum have been recently proposed as an alternative to the MSSM. In these models the electroweak scale is explained by a fine-tuning between different Higgs mass contributions (split-SUSY models), or by the localization of the Higgs sector in a point of an extra dimension whe

K. B. Vijaya Kumar, Yong-Liang Ma, Yue-Liang Wu

We have constructed a heavy baryon effective field theory with photon as an external field in accordance with the symmetry requirements similar to the heavy quark effective field theory. By treating the heavy baryon and anti-baryon equally on the same footing in the effective field theory, we have calculated the spin polarisabilities $γ_i, i=1...4$ of the nu

J. K. Parry

Realistic predictions are made for the rates of lepton flavour violating Higgs boson decays, tau --> mu gamma, mu --> e gamma, Bs --> mu+mu-, Bs --> tau mu and tau --> 3mu, via a top-down analysis of the Minimal Supersymmetric Standard Model(MSSM) constrained by SU(5) unification with right-handed Neutrinos and large tan beta. The third family neutrino Yukaw

Yasemin Sarac, Hungchong Kim, Su Houng Lee

We present a QCD sum rule analysis for the anti-charmed pentaquark state with and without strangeness. While the sum rules for most of the currents are either non-convergent or dominated by the $DN$ continuum, the one for the non-strange pentaquark current composed of two diquarks and an antiquark, is convergent and has a structure consistent with a positive

Kurusch Ebrahimi-Fard, Dirk Kreimer

The Hopf algebra structure underlying Feynman diagrams which governs the process of renormalization in perturbative quantum field theory is reviewed. Recent progress is briefly summarized with an emphasis on further directions of research.

M. Reiris

This paper has been withdrawn. (Reason) Its contents have been entirely superseded by the contents of the articles arXiv:0809.3444 and arXiv:0705.3070. There is no profitable reason to keep it alive. No material on it is however wrong.

Thomas W. Mattman, Gabriel Maybrun, Kristin Robinson

We prove that for 2-bridge knots, the diameter, D, of the set of boundary slopes is twice the crossing number, c. This constitutes partial verification of a conjecture that, for all knots in S^3, D is at most 2c.

Giacomo Mauro D&#39;Ariano, Vittorio Giovannetti, Paolo Perinotti

We consider the problem of estimating the ensemble average of an observable on an ensemble of equally prepared identical quantum systems. We show that, among all kinds of measurements performed jointly on the copies, the optimal unbiased estimation is achieved by the usual procedure that consists in performing independent measurements of the observable on ea

Satyabrata Adhikari

Suppose we are given two identical copies of an unknown quantum state and we wish to delete one copy from among the given two copies. The quantum no-deletion principle restricts us from perfectly deleting a copy but it does not prohibit us from deleting a copy approximately. Here we construct two types of a universal quantum deletion machine which approximat

Virendra Singh

We review here the main contributions of Einstein to the quantum theory. To put them in perspective we first give an account of Physics as it was before him. It is followed by a brief account of the problem of black body radiation which provided the context for Planck to introduce the idea of quantum. Einstein&#39;s revolutionary paper of 1905 on light-quant

Mihaly G. Benedict, Peter Foldi, F. M. Peeters

We discuss the effects caused by a resonant cavity around a sample of a magnetic molecular crystal (such as Mn${}_{12}$-Ac), when a time dependent external magnetic field is applied parallel to the easy axis of the crystal. We show that the back action of the cavity field on the sample significantly increases the possibility of microwave emission. This radia

Danuta Makowiec, Rafal Galaska, Aleksandra Dudkowska, Andrzej Rynkiewicz

The RR series extracted from human electrocardiogram signal (ECG) is considered as a fractal stochastic process. The manifestation of long-range dependencies is the presence of power laws in scale dependent process characteristics. Exponents of these laws: $β$ - describing power spectrum decay, $α$ - responsible for decay of detrended fluctuations or $H$ rel

Tao Hu, A. Yu. Grosberg, B. I. Shklovskii

It is known since the early days of molecular biology that proteins locate their specific targets on DNA up to two orders of magnitude faster than the Smoluchowski 3D diffusion rate. It was the idea due to Delbruck that they are non-specifically adsorbed on DNA, and sliding along DNA provides for the faster 1D search. Surprisingly, the role of DNA conformati

David Shalloway, Anton Faradjian

The generalized master equation or the equivalent continuous time random walk equations can be used to compute the macroscopic first passage time distribution (FPTD) of a complex stochastic system from short-term microscopic simulation data. The computation of the mean first passage time and additional low-order FPTD moments can be simplified by directly rel

P. A. Varotsos, N. V. Sarlis, E. S. Skordas, H. K. Tanaka

Electric signals have been recently recorded at the Earth&#39;s surface with amplitudes appreciably larger than those hitherto reported. Their entropy in natural time is smaller than that, $S_u$, of a ``uniform&#39;&#39; distribution. The same holds for their entropy upon time-reversal. This behavior, as supported by numerical simulations in fBm time series

M. Gersborg-Hansen, S. Balslev, N. A. Mortensen

We consider a recently reported micro-fluidic dye ring laser and study the full wave nature of TE modes in the cavity by means of finite-element simulations. The resonance wave-patterns of the cavity modes support a ray-tracing view and we are also able to explain the spectrum in terms of standing waves with a mode spacing dk = 2pi/L_eff where L_eff is the e

P. A. Varotsos, N. V. Sarlis, H. K. Tanaka, E. S. Skordas

We report a similarity of fluctuations in equilibrium critical phenomena and non-equilibrium systems, which is based on the concept of natural time. The world-wide seismicity as well as that of San Andreas fault system and Japan are analyzed. An order parameter is chosen and its fluctuations relative to the standard deviation of the distribution are studied.

Daniele Faccio, Miguel A. Porras, Audrius Dubietis, Francesca Bragheri

The precise observation of the angle-frequency spectrum of light filaments in water reveals a scenario incompatible with current models of conical emission (CE). Its description in terms of linear X-wave modes leads us to understand filamentation dynamics requiring a phase- and group-matched, Kerr-driven four-wave-mixing process that involves two highly loca

A. A. Mikhailov, P. P. Ammosov, G. A. Gavrilyeva, N. N. Efremov

The ozone layer state in the stratosphere over Yakutia depending on the year time is considered. It is shown that the layer thickness is maximum in February-March (450 Dobson&#39;s units) and it is minimum in July-September (300 - 350 DU). Measurements indicate that the ozone layer thickness was significantly decreased in the 1990&#39;s. A problem of change

Jennifer Riesz, Joel Gilmore, Paul Meredith

The optical scattering coefficient of a dilute, well solubilised eumelanin solution has been accurately measured as a function of incident wavelength, and found to contribute less than 6% of the total optical attenuation between 210 and 325nm. At longer wavelengths (325nm to 800nm) the scattering was less than the minimum sensitivity of our instrument. This

Debashish Munshi, Priya Kurian, Robert V. Bartlett, Akhlesh Lakhtakia

Mapping out the eight main nodes of nanotechnology discourse that have emerged in the past decade, we explore how various scientific, social, and ethical islands of discussion have developed, been recognized, and are being continually renegotiated. We do so by (1) identifying the ways in which scientists, policy makers, entrepreneurs, educators, and environm

D. Andreasi, S. Quaglioni, V. D. Efros, W. Leidemann

The two-body knock-out reaction 4He(e,e&#39;d)d is calculated at various momentum transfers. The full four-nucleon dynamics is taken into account microscopically both in the initial and the final states. As NN interaction the central MT-I/III potential is used. The calculation shows a strong reduction of the coincidence cross section due to the final state i

Grzegorz Stefanek

The elliptic flow of Lambda hyperons has been measured by the NA49 experiment in semi-central Pb+Pb collisions at 158 AGeV. The standard method of correlating particles with an event plane has been used. Measurements of v2 near mid-rapidity are reported as a function of rapidity, centrality and transverse momentum. Elliptic flow of Lambda particles increases

G. S. F. Stephans

The PHOBOS apparatus includes a charged particle multiplicity detector covering almost all of 4pi in solid angle. The broad coverage in pseudorapidity, $η$, which is unique at RHIC, combined with the ability to collect a large sample of events with minimal bias, makes possible a study of correlations and fluctuations over most of the pseudorapidity range, ev

Sarah-Louise Blyth

In ultra-relativistic heavy-ion collisions at $\sqrt{s_{NN}}$ = 5.5 TeV at the ALICE experiment at the LHC, interactions between the high-$p_{T}$ partons and the hot, dense medium produced in the collisions, are expected to lead to jet energy loss (jet-quenching) resulting in changes in the jet fragmentation functions as compared to the unquenched case. In o

Petr Chaloupka

We report on STAR analyses of p-lambda, p_bar-lambda_bar, p-lambda_bar, p_bar-lambda, p-p_bar and pi-Xi correlations in Au+Au collisions at sqrt(S_NN)=62 and 200 GeV. Measured source sizes in p(p_bar)-lambda(lambda_bar) and p-p_bar are shown to be in qualitative agreement with flow expectations. Interaction potential between p-lambda_bar, p_bar-lambda was in

Haibin Zhang

We present first results on D^0 meson production via direct reconstruction of its hadronic decay channel D^0->K pi in minimum bias Au+Au collisions at sqrt(s_(NN))=200 GeV with p_T up to ~3 GeV/c. Single electron spectra with 1<p_T<4 GeV/c from the charm semi-leptonic decays are also analyzed from the same data set. The charm production total cross-section p

Nicolas Leprovost, Sébatien Aumaitre, Kirone Mallick

A noisy damping parameter in the equation of motion of a nonlinear oscillator renders the fixed point of the system unstable when the amplitude of the noise is sufficiently large. However, the stability diagram of the system can not be predicted from the analysis of the moments of the linearized equation. In the case of a white noise, an exact formula for th

G. Boffetta, J. Davoudi, F. De Lillo

We study the anomalous scaling of the mass density measure of Lagrangian tracers in a compressible flow realized on the free surface on top of a three dimensional flow. The full two dimensional probability distribution of local stretching rates is measured. The intermittency exponents which quantify the fluctuations of the mass measure of tracers at small sc

S. V. Gonchenko, J. D. Meiss, I. I. Ovsyannikov

We study bifurcations of a three-dimensional diffeomorphism, $g_0$, that has a quadratic homoclinic tangency to a saddle-focus fixed point with multipliers $(λe^{i\vphi}, λe^{-i\vphi}, γ)$, where $0<λ<1<|γ|$ and $|λ^2γ|=1$. We show that in a three-parameter family, $g_{\eps}$, of diffeomorphisms close to $g_0$, there exist infinitely many open regions near $

D. J. Albers, J. C. Sprott

Results regarding probable bifurcations from fixed points are presented in the context of general dynamical systems (real, random matrices), time-delay dynamical systems (companion matrices), and a set of mappings known for their properties as universal approximators (neural networks). The eigenvalue spectra is considered both numerically and analytically us

Roberto Artuso, Lucia Cavallasca, Giampaolo Cristadoro

We consider a deterministic realization of Parrondo games and use periodic orbit theory to analyze their asymptotic behavior.

J. P. Wrubel, M. Sato, A. J. Sievers

Nearly steady-state locked intrinsic localized modes (ILMs) in the quasi-1d antiferromagnet (C2H5NH3)2CuCl4 are detected via four-wave mixing emission or the uniform mode absorption. Exploiting the long-time stability of these locked ILMs, repeatable nonlinear switching is observed by varying the sample temperature, and localized modes with various amplitude

Davar Khoshnevisan

We can view Brownian sheet as a sequence of interacting Brownian motions or slices. Here we present a number of results about the slices of the sheet. A common feature of our results is that they exhibit phase transition. In addition, a number of open problems are presented.

Jose Mijares

We introduce the relation of &#34;almost-reduction&#34; in an arbitrary topological Ramsey space R, as a generalization of the relation of &#34;almost-inclusion&#34; on the space of infinite sets of natural numbers (the Ellentuck space). This leads us to a type of ultrafilter U on the set of first approximations of the elements of R which corresponds to the

Denis Gaydashev, Dmitry Khmelev

The paper concerns numerical algorithms for solving the Beltrami equation $f_{\bar{z}}(z)=μ(z) f_z(z)$ for a compactly supported $μ$. First, we study an efficient algorithm that has been proposed in the literature, and present its rigorous justification. We then propose a different scheme for solving the Beltrami equation which has a comparable speed and acc

Mhyunghyun Oh, Kevin Zumbrun

We generalize work of Oh & Zumbrun and Serre on spectral stability of spatially periodic traveling waves of systems of viscous conservation laws from the one-dimensional to the multi-dimensional setting. Specifically, we extend to multi-dimensions the connection observed by Serre between the linearized dispersion relation near zero frequency of the linearize

Monica Ilie, Nico Spronk

We study the closed algebra B_I(G) generated by the idempotents in the Fourier-Stieltjes algebra of a locally compact group G. We show that it is a regular Banach algebra with computable spectrum G^I, which we call the idempotent compactification of G. For any locally compact groups G and H, we show that B_I(G) is completely isometrically isomorphic to B_I(H

Magda Peligrad, Sergey Utev

Braverman, Mallows and Shepp (1995), showed that if the absolute moments of partial sums of i.i.d. symmetric variables are equal to those of normal variables, then the marginals have normal distribution. This fact suggested the conjecture that probably the absolute moments alone characterize the homogeneous process with independent increments. In this paper

Zoran Škoda

The main theorem of the paper allows to generalize a class of identities among the quantum minors for quantum linear groups to similar identities but with the row labels of the quantum minors involved permuted.

Tetsuya Hosaka

In this paper, we study dense subsets of boundaries of CAT(0) groups. Suppose that a group $G$ acts geometrically on a CAT(0) space $X$ and suppose that there exists an element $g_0\in G$ such that (1) $Z_{g_0}$ is finite, (2) $X\setminus F_{g_0}$ is not connnected, and (3) each component of $X\setminus F_{g_0}$ is convex and not $g_0$-invariant, where $Z_{g

Tetsuya Hosaka

In this paper, we show that the center of every Coxeter group is finite and isomorphic to $(\Z_2)^n$ for some $n\ge 0$. Moreover, for a Coxeter system $(W,S)$, we prove that $Z(W)=Z(W_{S\setminus\tilde{S}})$ and $Z(W_{\tilde{S}})=1$, where $Z(W)$ is the center of the Coxeter group $W$ and $\tilde{S}$ is the subset of $S$ such that the parabolic subgroup $W_{

Tetsuya Hosaka

In this paper, we investigate the fixed-point set of an element of a CAT(0) group in its boundary. Suppose that a group $G$ acts geometrically on a CAT(0) space $X$. Let $g\in G$ and let $\mathcal{F}_g$ be the fixed-point set of $g$ in the boundary $\partial X$. Then we show that $\mathcal{F}_g=L(Z_g)$, where $Z_g$ is the centralizer of $g$ (i.e. $Z_g=\{v\in

Jordan S. Ellenberg, Julianna S. Tymoczko

The unipotent subgroup of a finite group of Lie type over a prime field Z/pZ comes equipped with a natural set of generators; the properties of the Cayley graph associated to this set of generators have been much studied. In the present paper, we show that the diameter of this Cayley graph is bounded above and below by constant multiples of np + n^2 log p, w

Serge Richard

We present some improvements in the method of the weakly conjugate operator, one variant of the Mourre theory. When applied to certain two-body Schroedinger operators, this leads to a limiting absorption principle that is uniform on the positive real axis.

Komei Fukuda, Sonoko Moriyama, Hiroki Nakayama

Richter-Gebert proved that every non-Euclidean uniform oriented matroid admits a biquadratic final polynomial. We extend this result to the non-uniform case.

Fabrizio Catanese, Fabio Tonoli

We determine the possible even sets of nodes on sextic surfaces in $\Pn 3$, showing in particular that their cardinalities are exactly the numbers in the set $\{24, 32, 40, 56 \}$. We also show that all the possible cases admit an explicit description. The methods that we use are an interplay of coding theory and projective geometry on one hand, of homologic

K. Hamza, F. C. Klebaner

This note is concerned with an important for modelling question of existence of solutions of stochastic partial differential equations as proper stochastic processes, rather than processes in the generalized sense. We consider a first order stochastic partial differential equations of the form $\pd Ut = DW$, and $\pd Ut-\pd Ux= DW$, where $D$ is a differenti

Shu-Cheng Chang, Jih-Hsin Cheng, Hung-Lin Chiu

Let $(\mathbf{M}^{3},J,θ_{0})$ be a closed pseudohermitian 3-manifold. Suppose the associated torsion vanishes and the associated $Q$-curvature has no kernel part with respect to the associated Paneitz operator. On such a background pseudohermitian 3-manifold, we study the change of the contact form according to a certain version of normalized $Q$-curvature

Angel Montesinos-Amilibia

We exhibit several transformations of surfaces in R^4. First, one that takes a flat surface and gets a surface with flat normal bundle; then, one that takes a surface with flat normal bundle and gets a flat surface; finally, a one-parameter family of transformations on a flat surface with flat normal bundle and gives a flat surface with flat normal bundle. T

A. V. Isaev

We introduce analogues of a map due to Rossi and show how they can be used to explicitly determine all covers of certain homogeneous strongly pseudoconvex 3-dimensional hypersurfaces that appear in the classification obtained by E. Cartan in 1932.

Hartmut Pecher

The Cauchy problem for a coupled system of the Schroedinger and the KdV equation is shown to be globally well-posed for data with infinite energy. The proof uses refined bilinear Strichartz estimates and the I-method introduced by Colliander, Keel, Staffilani, Takaoka, and Tao.

Alessia Cattabriga, Michele Mulazzani

We present two different representations of (1,1)-knots and study some connections between them. The first representation is algebraic: every (1,1)-knot is represented by an element of the pure mapping class group of the twice punctured torus. The second representation is parametric: every (1,1)-knot can be represented by a 4-tuple of integer parameters. The

Andreas Axelsson, Stephen Keith, Alan McIntosh

We solve the Kato square root problem for second order elliptic systems in divergence form under mixed boundary conditions on Lipschitz domains. This answers a question posed by J.-L. Lions in 1962. To do this we develop a general theory of quadratic estimates and functional calculi for complex perturbations of Dirac-type operators on Lipschitz domains.

Julianna S. Tymoczko

We study subvarieties of the flag variety called Hessenberg varieties, defined by certain linear conditions. These subvarieties arise naturally in applications including geometric representation theory, number theory, and numerical analysis. We describe completely the homology of Hessenberg varieties over GL_n(C) and show that they have no odd-dimensional ho

Hongyu He

In his article &#34;Transcending Classical Invariant Theory&#34; (J.A.M.S., 1989, Vol 2), Roger Howe established a correspondence between representations of a dual pair of reductive groups. This correspondence is known as Howe&#39;s correspondence or local theta correspondence. In my paper &#34;Unitary Representations and Theta Correspondence for Classical G

Arjan Keurentjes

Theories with General Relativity as a sub-sector exhibit enhanced symmetries upon dimensional reduction, which is suggestive of ``exotic dualities&#39;&#39;. Upon inclusion of time-like directions in the reductions one can dualize to theories in different space-time signatures. We clarify the nature of these dualities and show that they are well captured by

A. Giveon, D. Kutasov

We generalize the discussion of hep-th/0509170 to charged black holes. For the two dimensional charged black hole, which is described by an exactly solvable worldsheet theory, a transition from the black hole to the string phase occurs when the Hawking temperature of the black hole reaches a limiting value, the temperature of free strings with the same mass

N. Beisert, R. Roiban

Worldsheet techniques can be used to argue for the integrability of string theory on AdS_5xS^5/Z_S, which is dual to the strongly coupled Z_S-orbifold of N=4 SYM. We analyze the integrability of these field theories in the perturbative regime and construct the relevant Bethe equations.

A. Aidaoui, A. Meziane, M. Tahiri

We use a Becchi-Rouet-Stora-Tyutin (BRST) superspace approach to formulate off-shell nilpotent BRST and anti-BRST transformations in four dimensional N=1 supersymmetric Yang-Mills theory. The method is based on the possibility of introducing auxiliary fields through the supersymmetric transformations of the superpartener of the gauge potential associated to

H. Arodz, P. Klimas, T. Tyranowski

In this lecture we outline the main results of our investigations of certain field-theoretic systems which have V-shaped field potential. After presenting physical examples of such systems, we show that in static problems the exact ground state value of the field is achieved on a finite distance - there are no exponential tails. This applies in particular to

Piero Nicolini

Adopting noncommutative spacetime coordinates, we determined a new solution of Einstein equations for a static, spherically symmetric matter source. The limitations of the conventional Schwarzschild solution, due to curvature singularities, are overcome. As a result, the line element is endowed of a regular DeSitter core at the origin and of two horizons eve

Y. M. Cho, D. G. Pak

Motivated by the instability of the Savvidy-Nielsen-Olesen (SNO) vacuum we make a systematic search for a stable magnetic background in pure SU(2) QCD. It is shown that Wu-Yang monopole-antimonopole pair is unstable under vacuum fluctuations. However, it is shown that a pair of axially symmetric monopole-antimonopole string configuration is stable, provided

A. Awad, N. Chamoun, S. Khalil

We study the effect of adding charged matter fields to both D3 and D7 branes in type IIB string theory compactification with fluxes. Generically, charged matter fields induce additional terms to the Kahler form, the superpotential and the D-terms. These terms allow for minima with positive or zero cosmological constants, even in the absence of non-perturbati

Su Jun-Chen, Zheng Fu-Hou

This paper has been superseded by hep-th/0510131.