January 2008 arXiv papers — page 3
Showing 201–300 of 4,749 papers
Eric R. Hudson, Nathan B. Gilfoy, Svetlana Kotochigova, Jeremy M. Sage
Ultra-cold RbCs molecules in high-lying vibrational levels of the a$^3Σ^+$ ground electronic state are confined in an optical trap. Inelastic collision rates of these molecules with both Rb and Cs atoms are determined for individual vibrational levels, across an order of magnitude of binding energies. A simple model for the collision process is shown to accu
Alan Rust, Brian Bishop, Kevin McDaid
It is widely documented that the absence of a structured approach to spreadsheet engineering is a key factor in the high level of spreadsheet errors. In this paper we propose and investigate the application of Test-Driven Development to the creation of spreadsheets. Test-Driven Development is an emerging development technique in software engineering that has
J. Greiner, W. Bornemann, C. Clemens, M. Deuter
We describe the construction of GROND, a 7-channel imager, primarily designed for rapid observations of gamma-ray burst afterglows. It allows simultaneous imaging in the Sloan g'r'i'z' and near-infrared $JHK$ bands. GROND was commissioned at the MPI/ESO 2.2m telescope at La Silla (Chile) in April 2007, and first results of its performance and
Nikodem J. Poplawski
The metric-affine Lagrangian of Ponomarev and Obukhov for the unified gravitational and electromagnetic field is linear in the Ricci scalar and quadratic in the tensor of homothetic curvature. We apply to this Lagrangian the variational principle with the tetrad and spin connection as dynamical variables and show that, in this approach, the field equations a
T. Hobbs, W. Melnitchouk
Parity-violating deep inelastic scattering (PVDIS) has been proposed as an important new tool to extract the flavor and isospin dependence of parton distributions in the nucleon. We discuss finite-Q^2 effects in PVDIS asymmetries arising from subleading kinematical corrections and longitudinal contributions to the photon-Z interference. For the proton, these
Joel Ratsaby
Kolmogorov argued that the concept of information exists also in problems with no underlying stochastic model (as Shannon's information representation) for instance, the information contained in an algorithm or in the genome. He introduced a combinatorial notion of entropy and information $I(x:\sy)$ conveyed by a binary string $x$ about the unknown value
Minho Son, Raman Sundrum
We study a five-dimensional supergravity model with boundary-localized visible sector exhibiting anomaly-mediated supersymmetry breaking, in which the central requirements of sequestering and radius stabilization are achieved perturbatively. This makes it possible to understand these various mechanisms in a more integrated and transparent fashion, mostly fro
Exciton Gas Compression and Metallic Condensation in a Single Semiconductor Quantum Wire
cond-mat.str-elBenito Alen, David Fuster, Guillermo Munoz-Matutano, Juan Martinez-Pastor
We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidences of metallic liquid condensation at low temperatures. Firstly, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Secondly, we fin
Tatsuhiro Misumi
This paper has been withdrawn by the author, due to the crucial mistake of the discussion in Sec IV.
Chandra X-ray Grating Spectrometry of Eta Carinae near X-ray Minimum: I. Variability of the Sulfur and Silicon Emission Lines
astro-phD. B. Henley, M. F. Corcoran, J. M. Pittard, I. R. Stevens
We report on variations in important X-ray emission lines in a series of Chandra grating spectra of the supermassive colliding wind binary star Eta Carinae, including key phases around the X-ray minimum/periastron passage in 2003.5. The X-rays arise from the collision of the slow, dense wind of Eta Car with the fast, low-density wind of an otherwise hidden c
D. Nagy, G. Szirmai, P. Domokos
The spatial self-organization of a Bose-Einstein condensate (BEC) in a high-finesse linear optical cavity is discussed. The condensate atoms are laser-driven from the side and scatter photons into the cavity. Above a critical pump intensity the homogeneous condensate evolves into a stable pattern bound by the cavity field. The transition point is determined
Arundhati Dasgupta
I give a resolution of the conformal mode divergence in the Euclidean gravitational path-integral by isolating the trace of the diffeomorphisms and its contribution to the Faddeev-Popov measure.
Lode Wylleman
The general line element corresponding to the family of algebraically general, gravito-electric, expanding, rotating dust models with one functionally independent zero-order Riemann invariant is constructed. The isometry group is at most one-dimensional but generically trivial. It is shown that the asymmetric solutions with constant ratio of energy density a
D. S. Novikov, V. G. Kiselev
We consider the NMR signal from a permeable medium with a heterogeneous Larmor frequency component that varies on a scale comparable to the spin-carrier diffusion length. We focus on the mesoscopic part of the transverse relaxation, that occurs due to dispersion of precession phases of spins accumulated during diffusive motion. By relating the spectral lines
R. Feldmann, L. Mayer, C. M. Carollo
We use a set of high-resolution N-body simulations of binary galaxy mergers to show that the morphologies of the tidal features that are seen around a large fraction of nearby, massive ellipticals in the field, cannot be reproduced by equal-mass dissipationless mergers; rather, they are well explained by the accretion of disk-dominated galaxies. In particula
A. M. Hughes, D. J. Wilner, C. Qi, M. R. Hogerheijde
We investigate the apparent discrepancy between gas and dust outer radii derived from millimeter observations of protoplanetary disks. Using 230 and 345 GHz continuum and CO J=3-2 data from the Submillimeter Array for four nearby disk systems (HD 163296, TW Hydrae, GM Aurigae, and MWC 480), we examine models of circumstellar disk structure and the effects of
M. Nardini, G. Ghisellini, G. Ghirlanda
We show that Gamma Ray Bursts (GRBs) of known redshift and rest frame optical extinction detected by the Swift satellite fully confirm earlier results concerning the distribution of the optical afterglow luminosity at 12 hours after trigger (rest frame time). This distribution is bimodal and relatively narrow, especially for the high luminosity branch. This
R. E. Kastner
A modified version of Young's experiment by Shahriar Afshar indirectly reveals the presence of a fully articulated interference pattern prior to the post-selection of a particle in a "which-slit" basis. While this experiment does not constitute a violation of Bohr's Complementarity Principle as claimed by Afshar, both he and many of his criti
Wei Li, Wei Song, Andrew Strominger
Three dimensional Einstein gravity with negative cosmological constant -1/\ell^2 deformed by a gravitational Chern-Simons action with coefficient 1/μis studied in an asymptotically AdS_3 spacetime. It is argued to violate unitary or positivity for generic μdue to negative-energy massive gravitons. However at the critical value μ\ell=1, the massive gravitons
Daniel Goldstein, Robert M. Guralnick, Everett W. Howe, Michael E. Zieve
We show that one can find two nonisomorphic curves over a field K that become isomorphic to one another over two finite extensions of K whose degrees over K are coprime to one another. More specifically, let K_0 be an arbitrary prime field and let r and s be integers greater than 1 that are coprime to one another. We show that one can find a finite extension
Sean Sather-Wagstaff
We investigate the set S(R) of shift-isomorphism classes of semidualizing R-complexes, ordered via the reflexivity relation, where R is a commutative noetherian local ring. Specifically, we study the question of whether S(R$ has cardinality 2^n for some n. We show that, if there is a chain of length n in S(R) and if the reflexivity ordering on S(R) is transi
Toward Best Isoperimetric Constants for $(H^1,BMO)$-Normal Conformal Metrics on $\mathbb R^n$, $n\ge 3$
math.DGJie Xiao
The aim of this article is: (a) To establish the existence of the best isoperimetric constants for the $(H^1,BMO)$-normal conformal metrics $e^{2u}|dx|^2$ on $\mathbb R^n$, $n\ge 3$, i.e., the conformal metrics with the Q-curvature orientated conditions $$ (-Δ)^{n/2}u\in H^1(\mathbb R^n) & \ u(x)=\hbox{const.}+\frac{\int_{\mathbb R^n}(\log\frac{|\cdot|}{|x-\
Factorization of e+e- Event Shape Distributions with Hadronic Final States in Soft Collinear Effective Theory
hep-phChristian W. Bauer, Sean Fleming, Christopher Lee, George Sterman
We present a new analysis of two-jet event shape distributions in soft collinear effective theory. Extending previous results, we observe that a large class of such distributions can be expressed in terms of vacuum matrix elements of operators in the effective theory. We match these matrix elements to the full theory in the two-jet limit without assuming fac
Low-Luminosity Gamma-Ray Bursts as a Distinct GRB Population:A Firmer Case from Multiple Criteria Constraints
astro-phFrancisco Virgili, Enwei Liang, Bing Zhang
The intriguing observations of Swift/BAT X-ray flash XRF 060218 and the BATSE-BeppoSAX gamma-ray burst GRB 980425, both with much lower luminosity and redshift compared to other observed bursts, naturally lead to the question of how these low-luminosity (LL) bursts are related to high-luminosity (HL) bursts. Incorporating the constraints from both the flux-l
Stephen L. Adler, J. Gamboa, F. Mendez, J. Lopez-Sarrion
We give a detailed study of axion-photon and photon-axion conversion amplitudes, which enter the analysis of ``light shining through a wall'' experiments. Several different calculational methods are employed and compared, and in all cases we retain a nonzero axion mass. To leading order, we find that when the photon frequency $ω$ is very close to the
Virtual dielectric waveguide mode description of a high-gain free-electron laser I: Theory
physics.opticsErik Hemsing, Avraham Gover, James Rosenzweig
A set of mode-coupled excitation equations for the slowly-growing amplitudes of dielectric waveguide eigenmodes is derived as a description of the electromagnetic signal field of a high-gain free-electron laser, or FEL, including the effects of longitudinal space-charge. This approach of describing the field basis set has notable advantages for FEL analysis
Concerning Olga, the Beautiful Little Street Dancer (Adjectives as Higher-Order Polymorphic Functions)
cs.CLWalid S. Saba
In this paper we suggest a typed compositional seman-tics for nominal compounds of the form [Adj Noun] that models adjectives as higher-order polymorphic functions, and where types are assumed to represent concepts in an ontology that reflects our commonsense view of the world and the way we talk about it in or-dinary language. In addition to [Adj Noun] comp
Patrick Labarque
The proof uses the property that the vertices of a triangulated planar graph can be four coloured if the triangles can have a +1 or -1 orientation so that the sum of the triangle orientations around each vertex is a multiple of 3. Such orientation is first used separately on one of the two triangulated polygons resulting from a Hamilton circuit in a triangul
Miroslava Sotakova
In this paper we study one-round key-agreement protocols analogous to Merkle's puzzles in the random oracle model. The players Alice and Bob are allowed to query a random permutation oracle $n$ times and upon their queries and communication, they both output the same key with high probability. We prove that Eve can always break such a protocol by queryin
Freddy Cachazo, David Skinner
Exploiting singularities in Feynman integrals to get information about scattering amplitudes has been particularly useful at one-loop in theories where no triangles or bubbles appear. At higher loops the integrals possess subtle singularities. In this paper we give these singularities a physical interpretation and show how they turn tedious computations into
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - II. Cosmological simulations of galaxy clusters
astro-phL. Iapichino, J. C. Niemeyer
The development of turbulent gas flows in the intra-cluster medium and in the core of a galaxy cluster is studied by means of adaptive mesh refinement (AMR) cosmological simulations. A series of six runs was performed, employing identical simulation parameters but different criteria for triggering the mesh refinement. In particular, two different AMR strateg
G. S. Bisnovatyi-Kogan
The following problems are discussed. 1. Pulsars and close binaries. 2. Hulse-Taylor pulsar. 3. Disrupted pulsar pairs. 4. RP statistics. 5. Enhanced evaporation: formation of single RP. 6. General relativity effects: NS+NS. 7. A Double pulsar system. 8. Checking general relativity. 9. Variability of the gravitational constant. 10. Space Watch.
Monwhea Jeng, Mark J. Bowick, Werner Krauth, Jennifer Schwarz
We study vacancy diffusion on the classical triangular lattice dimer model, sub ject to the kinetic constraint that dimers can only translate, but not rotate. A single vacancy, i.e. a monomer, in an otherwise fully packed lattice, is always localized in a tree-like structure. The distribution of tree sizes is asymptotically exponential and has an average of
Alexander Kusenko, Bhabani Prasad Mandal, Alok Mukherjee
The observed velocities of pulsars suggest the possibility that sterile neutrinos with mass of several keV are emitted from a cooling neutron star. The same sterile neutrinos could constitute all or part of cosmological dark matter. The neutrino-driven kicks can exhibit delays depending on the mass and the mixing angle, which can be compared with the pulsar
Pierre Carmier, Ullmo Denis
We derive a semiclassical expression for the Green's function in graphene, in which the presence of a semiclassical phase is made apparent. The relationship between this semiclassical phase and the adiabatic Berry phase, usually referred to in this context, is discussed. These phases coincide for the perfectly linear Dirac dispersion relation. They diffe
Alexander V. Gnedin, Alexander M. Iksanov, Pavlo Negadajlov, Uwe Rösler
We consider an occupancy scheme in which "balls" are identified with $n$ points sampled from the standard exponential distribution, while the role of "boxes" is played by the spacings induced by an independent random walk with positive and nonlattice steps. We discuss the asymptotic behavior of five quantities: the index $K_n^*$ of the last o
Hydrodynamical adaptive mesh refinement simulations of turbulent flows - I. Substructure in a wind
astro-phL. Iapichino, J. Adamek, W. Schmidt, J. C. Niemeyer
The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR simulations performed with the usual refinement criteria based on local gradients of selected variables do not properly reso
Victoria Gitman
One of the numerous characterizations of a Ramsey cardinal kappa involves the existence of certain types of elementary embeddings for transitive sets of size κsatisfying a large fragment of ZFC. We introduce new large cardinal axioms generalizing the Ramsey elementary embeddings characterization and show that they form a natural hierarchy between weakly comp
Claudio Carmeli, Teiko Heinosaari, Juha-Pekka Pellonpää, Alessandro Toigo
Given a unitary representation U of a compact group G and a transitive G-space $Ω$, we characterize the extremal elements of the convex set of all U-covariant positive operator valued measures.
S. Ianus, S. Marchiafava, L. Ornea, R. Pantilie
We introduce a natural notion of quaternionic map between almost quaternionic manifolds and we prove the following, for maps of rank at least one: 1) A map between quaternionic manifolds endowed with the integrable almost twistorial structures is twistorial if and only if it is quaternionic. 2) A map between quaternionic manifolds endowed with the nonintegra
Differential equations with discrete state-dependent delay: uniqueness and well-posedness in the space of continuous functions
math.APAlexander V. Rezounenko
Partial differential equations with discrete (concentrated) state-dependent delays in the space of continuous functions are investigated. In general, the corresponding initial value problem is not well posed, so we find an additional assumption on the state-dependent delay function to guarantee the well posedness. For the constructed dynamical system we stud
S. Albeverio, S. V. Kozyrev
The general construction of frames of p-adic wavelets is described. We consider the orbit of a mean zero generic locally constant function with compact support (mean zero test function) with respect to the action of the p-adic affine group and show that this orbit is a uniform tight frame. We discuss relation of this result to the multiresolution wavelet ana
Toru T. Takahashi, Teiji Kunihiro
We show the first lattice QCD results on the axial charge $g_A^{N^*N^*}$ of $N^*(1535)$ and $N^*(1650)$. The measurements are performed with two flavors of dynamical quarks employing the renormalization-group improved gauge action at $β$=1.95 and the mean-field improved clover quark action with the hopping parameters, $κ$=0.1375, 0.1390 and 0.1400. In order
P. Pad, F. Marvasti, K. Alishahi, S. Akbari
In this paper we introduce a new class of codes for over-loaded synchronous wireless and optical CDMA systems which increases the number of users for fixed number of chips without introducing any errors. Equivalently, the chip rate can be reduced for a given number of users, which implies bandwidth reduction for downlink wireless systems. An upper bound for
J. Fuchs, J. Schelter, F. Ginelli, H. Hinrichsen
We revisit the problem of local persistence in directed percolation, reporting improved estimates of the persistence exponent in 1+1 dimensions, discovering strong corrections to scaling in higher dimensions, and investigating the mean field limit. Moreover, we introduce a graded persistence probability that a site does not flip more than n times and demonst
Adolfo De Unánue, Daniel Sudarsky
The standard inflationary version of the origin of the cosmic structure as the result of the quantum fluctuations during the early universe is less than fully satisfactory as has been argued in [A. Perez, H. Sahlmann, and D. Sudarsky, Class. Quantum Grav., 23, 2317, (2006)]. A proposal is made there of a way to address the shortcomings by invoking a process
Kathleen Reif Volz
In this paper, we study the hyperbolicity of arborescent tangles and arborescent links. We will explicitly determine all essential surfaces in arborescent tangle complements with non-negative Euler characteristic, and show that given an arborescent tangle T, the complement X(T) is non-hyperbolic if and only if T is a rational tangle, T=Q_m * T' for some
Frances Kirwan
Given a suitable action on a complex projective variety X of a non-reductive affine algebraic group H, this paper considers how to choose a reductive group G containing H and a projective completion of G x_H X which is a reductive envelope in the sense of math.AG/0703131. In particular it studies the family of examples given by moduli spaces of hypersurfaces
Stephen C. Davis, Marieke Postma
Chaotic inflation predicts a large gravitational wave signal which can be tested by the upcoming Planck satellite. We discuss a SUGRA implementation of chaotic inflation in the presence of moduli fields, and find that inflation does not work with a generic KKLT moduli stabilisation potential. A viable model can be constructed with a fine-tuned moduli sector,
G. I. Lykasov, A. N. Sissakian, A. S. Sorin, V. D. Toneev
In-medium effects on transverse-mass distributions of quarks and gluons are considered assuming a possible local equilibrium for colorless quark objects (mesons and baryons) created in central A-A collisions. It is shown that the average transverse momentum squared for these partons grows and then saturates when the initial energy increases. Within the quark
Carlo Giunti
It is shown that neutrino mixing cannot explain the GSI time anomaly, refuting recent claims in this direction. Addendum 1: Remarks on arXiv:0801.1465. Addendum 2: Quantum effects in GSI nuclear decay.
Giuseppe D'Appollonio, Thomas Quella
In this paper we study the diagonal cosets of the non-compact H4 WZW model. Generalising earlier work by Antoniadis and Obers, we provide an exact world-sheet description for several families of non-maximally symmetric gravitational plane waves with background NS fluxes. We show that the sigma-models that correspond to an asymmetric action of the gauge group
Burcu Baran
In this note we give an explicit parametrization of the modular curve associated to the normalizer of a non-split Cartan subgroup of level 9. We determine all integral points of this modular curve. As an application, we give an alternative solution to the class number one problem.
B. Posselt, S. B. Popov, F. Haberl, J. Truemper
Context: Isolated cooling neutron stars with thermal X-ray emission remain rarely detected objects despite many searches investigating the ROSAT data. Aims: We simulate the population of close-by young cooling neutron stars to explain the current observational results. Given the inhomogeneity of the neutron star distribution on the sky it is particularly int
Marco Valerio Battisti, Giovanni Montani
The cosmological implications of an evolutionary quantum gravity are analyzed in the context of a generic inhomogeneous model. The Schrödinger problem is formulated and solved in the presence of a scalar field, an ultrarelativistic matter and a perfect gas regarded as the dust-clock. Considering the actual phenomenology, it is shown how the evolutionary appr
E. Athanassoula, F. -S. Ling, E. Nezri, R. Teyssier
In this paper, we estimate the gamma-ray and neutrino fluxes coming from dark matter annihilation in a Milky Way framework provided by a recent N-BODY HORIZON simulation. We first study the characteristics of the simulation and highlight the mass distribution within the galactic halo. The general dark matter density has a typical $r^{-3}$ power law for large
I. M. Suslov
The possible existence of the Anderson transition in 2D systems without interaction and spin-orbit effects (such as the usual Anderson model) becomes recently a subject of controversy in the literature. Comparative analysis of approaches based on generalized Lyapunov exponents is given, in order to resolve controversy.
Ángel Rivas, Alfredo Luis
We elaborate on a Hilbert-Schmidt distance measure assessing the intrinsic metrological accuracy in the detection of signals imprinted on quantum probe states by signal-dependent transformations. For small signals this leads to a probe-transformation measure $Λ$ fully symmetric on the probe $ρ$ and the generator $G$ of the transformation $Λ(ρ, G) = Λ(G, ρ)$.
S. Gallerani, A. Ferrara, X. Fan, Choudhury T. Roy
We provide measurements of the neutral hydrogen fraction xHI at z~6, by comparing semi-analytical models of the Lyalpha forest with observations of high-z quasars and Gamma Ray Bursts absorption spectra. We analyze the transmitted flux in a sample of 17 QSOs spectra at 5.74<zem<6.42 studying separately the narrow transmission windows (peaks) and the wide dar
Vladimir M. Miklyukov, Antti Rasila, Matti Vuorinen
We study stagnation zones of $\mathcal{A}$-harmonic functions on canonical domains in the Euclidean $n$-dimensional space. Phragmen-Lindelöf type theorems are proved.
Seid Bahlali
We consider in this paper, mixed relaxed-singular stochastic control problems, where the control variable has two components, the first being measure-valued and the second singular. The control domain is not necessarily convex and the system is governed by a nonlinear stochastic differential equation, in which the measure-valued part of the control enters bo
The strict and relaxed stochastic maximum principle for optimal control problem of backward systems
math.PRSeid Bahlali
We consider a stochastic control problem where the set of controls is not necessarily convex and the system is governed by a nonlinear backward stochastic differential equation. We establish necessary as well as sufficient conditions of optimality for two models. The first concerns the strict (classical) controls. The second is an extension of the first to r
Stochastic maximum principle for optimal control problem of backward systems with terminal condition in L1
math.PRSeid Bahlali
We consider a stochastic control problem, where the control domain is convex and the system is governed by a nonlinear backward stochastic differential equation. With a L1 terminal data, we derive necessary optimality conditions in the form of stochastic maximum principle.
Dusa McDuff
We show how to reduce the problem of symplectically embedding one 4-dimensional rational ellipsoid into another to a problem of embedding disjoint unions of balls into appropriate blow ups of \C P^2. For example, the problem of embedding the ellipsoid E(1,k) into a ball B is equivalent to that of embedding k disjoint equal balls into \C P^2, and so can be so
Sylvain Prolhac, Kirone Mallick
We use the Bethe Ansatz to derive analytical expressions for the current statistics in the asymmetric exclusion process with both forward and backward jumps. The Bethe equations are highly coupled and this fact has impeded their use to derive exact results for finite systems. We overcome this technical difficulty by a reformulation of the Bethe equations int
David Martinez-Delgado, Michael Pohlen, R. Jay Gabany, Steven R. Majewski
We report the discovery of a giant, loop-like stellar structure around the edge-on spiral galaxy NGC 4013. This arcing feature extends 6 arcmin (~26 kpc in projected distance) northeast from the center and 3 arcmin (~=12 kpc) from the disk plane; likely related features are also apparent on the southwest side of the disk, extending to 4 arcmin (~17 kpc). The
Arif Akhundov
The status of the precision tests of the electroweak interactions is reviewed in this paper. An emphasis is put on the Standard Model analysis based on measurements at LEP/SLC and the Tevatron. The results of the measurements of the electroweak mixing angle in the NuTeV experiment and the future prospects are discussed.
Seung-il Nam, Hyun-Chul Kim
We investigate the pion electromagnetic charge radii and mass dropping of the rho meson at finite density. We first calculate the pion charge radii within the framework of the nonlocal chiral quark model from the instanton vacuum both at zero and finite densities. In order to relate the change of the pion charge radius to that of the rho-meson mass at finite
Andreas E. Kyprianou, Ronnie Loeffen
Motivated by classical considerations from risk theory, we investigate boundary crossing problems for refracted Lévy processes. The latter is a Lévy process whose dynamics change by subtracting off a fixed linear drift (of suitable size) whenever the aggregate process is above a pre-specified level. More formally, whenever it exists, a refracted Lévy process
Roldao da Rocha, Alex E. Bernardini, Jayme Vaz
The Minkowski spacetime quantum Clifford algebra structure associated with the conformal group and the Clifford-Hopf alternative k-deformed quantum Poincare algebra is investigated in the Atiyah-Bott-Shapiro mod 8 theorem context. The resulting algebra is equivalent to the deformed anti-de Sitter algebra U_q(so(3,2)), when the associated Clifford-Hopf algebr
The relative roles of divergence and velocity slip in the stability of plane channel flow
physics.flu-dynK. C. Sahu, A. Sameen, R. Govindarajan
Wall slip and wall divergence are known to have large and opposing effects on the stability of flow in a two-dimensional channel. While divergence hugely destabilises, slip dramatically stabilizes the linear mode. In a non-parallel stability analysis, we study a combination of these two effects, since both will coexist in small-scale flows with wall roughnes
Benjamin Koch
In this paper it is shown that an equivalent to the complex Klein-Gordon equation can be obtained from the (2+3) dimensional Einstein equations coupled to a conserved energy momentum tensor. In an explicit toy model we give matching conditions for what corresponds to the phase, the amplitude, and the mass of the complex wave function.
S. W. Ham, E. J. Yoo, S. K. OH, D. Son
We study the scalar Higgs sector of the next-to-minimal supersymmetric standard model with an extra U(1), which has two Higgs doublets and a Higgs singlet, in the light leptophobic $Z'$ scenario where the extra neutral gauge boson $Z'$ does not couple to charged leptons. In this model, we find that the sum of the squared coupling coefficients of the
J. K. Canci
Let $K$ be a number field. Let $S$ be a finite set of places of $K$ containing all the archimedean ones. Let $R_S$ be the ring of $S$-integers of $K$. In the present paper we consider endomorphisms of $\pro$ of degree 2, defined over $K$, with good reduction outside $S$. We prove that there exist only finitely many such endomorphisms, up to conjugation by ${
Benedikt M. Pötscher, Ulrike Schneider
We study the distribution of the adaptive LASSO estimator (Zou (2006)) in finite samples as well as in the large-sample limit. The large-sample distributions are derived both for the case where the adaptive LASSO estimator is tuned to perform conservative model selection as well as for the case where the tuning results in consistent model selection. We show
Kari Astala, James Gill, Steffen Rohde, Eero Saksman
Let $f:Ω\to\IR^2$ be a mapping of finite distortion, where $Ω\subset\IR^2 .$ Assume that the distortion function $K(x,f)$ satisfies $e^{K(\cdot, f)}\in L^p_{loc}(Ω)$ for some $p>0.$ We establish optimal regularity and area distortion estimates for $f$. Especially, we prove that $|Df|^2 \log^{β-1}(e + |Df|) \in L^1_{loc}(Ω) $ for every $β<p.$ This answers pos
Z. Y. Xu, M. Feng, W. M. Zhang
We investigate the possibility to have electron-pairs in dephasing-free subspace (DFS), by means of the quantum-dot cellular automata (QCA) and single-spin rotations, to carry out a high-fidelity and deterministic universal quantum computation. We show that our QCA device with electrons tunneling two dimensionally is very suitable for DFS encoding, and argue
The circular loop equation of a cosmic string with time-varying tension in de Sitter spacetimes
hep-thYunqi Liu, Hongbo Cheng
In this work the equation of circular loops of cosmic string possessing time-dependent tension is studied in the de Sitter spacetime. We find that the cosmic string loops with initial radius $r(t_{0})>0.707L$, L de Sitter radius, should not collapse to form a black holes. It is also found that in the case of $r(t_{0})<0.707L$ a loop of cosmic string whose te
Karim Lounici
We derive the $l_{\infty}$ convergence rate simultaneously for Lasso and Dantzig estimators in a high-dimensional linear regression model under a mutual coherence assumption on the Gram matrix of the design and two different assumptions on the noise: Gaussian noise and general noise with finite variance. Then we prove that simultaneously the thresholded Lass
Twisted cyclic theory and an index theory for the gauge invariant KMS state on Cuntz algebras
math.KTA. L. Carey, J. Phillips, A. Rennie
This paper presents, by example, an index theory appropriate to algebras without trace. Whilst we work exclusively with the Cuntz algebras the exposition is designed to indicate how to develop a general theory. Our main result is an index theorem (formulated in terms of spectral flow) using a twisted cyclic cocycle where the twisting comes from the modular a
G. Christopher Hruska
We lay the foundations for the study of relatively quasiconvex subgroups of relatively hyperbolic groups. These foundations require that we first work out a coherent theory of countable relatively hyperbolic groups (not necessarily finitely generated). We prove the equivalence of Gromov, Osin, and Bowditch's definitions of relative hyperbolicity for coun
Hua-Xing Chen, Xiang Liu, Atsushi Hosaka, Shi-Lin Zhu
We study the mass of the state Y(2175) of J^{PC} = 1^{--} in the QCD sum rule. We construct both the diquark-antidiquark currents (ss)(s_bar s_bar) and the meson-meson currents (s_bar s)(s_bar s). We find that there are two independent currents for both cases, and derive the relations between them. The OPE convergence of these two currents is sufficiently fa
Mesfin Asfaw
We discuss the effect of subdividing the ratchet potential on the performance of a tiny Brownian heat engine that is modeled as a Brownian particle hopping in a viscous medium in a sawtooth potential (with or without load) assisted by alternately placed hot and cold heat baths along its path. We show that the velocity, the efficiency and the coefficient of p
Katsunori Kawamura
Let ${\sf CK}_{*}$ denote the C$^{*}$-algebra defined by the direct sum of all Cuntz-Krieger algebras. We introduce a comultiplication $Δ_ϕ$ and a counit $ε$ on ${\sf CK}_{*}$ such that $Δ_ϕ$ is a nondegenerate $*$-homomorphism from ${\sf CK}_{*}$ to ${\sf CK}_{*}\otimes {\sf CK}_{*}$ and $ε$ is a $*$-homomorphism from ${\sf CK}_{*}$ to ${\bf C}$. From this,
Yue Wang, John C. S. Lui, Dah-Ming Chiu
Recent works show conflicting results: network capacity may increase or decrease with higher transmission power under different scenarios. In this work, we want to understand this paradox. Specifically, we address the following questions: (1)Theoretically, should we increase or decrease transmission power to maximize network capacity? (2) Theoretically, how
Thi-Anh-Thu Dinh
Let $\mathcal{A}$ be a line arrangement in the complex projective plane $\mathbb{P}^2$, having the points of multiplicity $\geq 3$ situated on two lines in $\mathcal{A}$, say $H_0$ and $H_{\infty}$. Then we show that the non-local irreducible components of the first resonance variety $\mathcal{R}_1(\mathcal{A})$ are 2-dimensional and correspond to parallelog
Rodrigo Aros
In this article is shown that the thermodynamical evolution of a Schwarzschild de Sitter space is the evaporation of its black hole. The result is extended in higher dimensions to Lovelock theories of gravity with a single positive cosmological constant.
The KamLAND Collaboration
The KamLAND experiment has determined a precise value for the neutrino oscillation parameter $Δm^{2}_{21}$ and stringent constraints on $θ_{12}$. The exposure to nuclear reactor anti-neutrinos is increased almost fourfold over previous results to 2.44$\times10^{32}$ proton-yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor $\ba
Joan E. Licata
This paper presents a new algorithm "A" for constructing Seifert surfaces from n-bridge projections of links. The algorithm produces minimal complexity surfaces for large classes of braids and alternating links. In addition, we consider a family of knots for which the canonical genus is strictly greater than the genus, (g_c(K) > g(K)), and show that
Thomas Gregoire, Emanuel Katz
We investigate the decay of particles with the quantum numbers of the gluino. Besides SUSY, such particles may be present in models where the Higgs and top are composite. We find that such 'composite' gluinos have decay signatures similar to those of gluinos in 'more minimal' SUSY type models. Though it is in principle possible to distinguish
Oscar A. Barraza, Laura B. Langoni
We study the asymptotic behavior of nonnegative solutions of the semilinear parabolic problem {u_t=Δu + u^{p}, x\in\mathbb{R}^{N}, t>0 u(0)=u_{0}, x\in\mathbb{R}^{N}, t=0. It is known that the nonnegative solution $u(t)$ of this problem blows up in finite time for $1<p\leq 1+ 2/N$. Moreover, if $p> 1+ 2/N$ and the norm of $u_{0}$ is small enough, the problem
Control of Four-Level Quantum Coherence via Discrete Spectral Shaping of an Optical Frequency Comb
quant-phMatthew C. Stowe, Avi Pe'er, Jun Ye
We present an experiment demonstrating high-resolution coherent control of a four-level atomic system in a closed (diamond) type configuration. A femtosecond frequency comb is used to establish phase coherence between a pair of two-photon transitions in cold Rb atoms. By controlling the spectral phase of the frequency comb we demonstrate the optical phase se
Is a binary fraction-age relation responsible for the lack of EHB binaries in globular clusters?
astro-phC. Moni Bidin, M. Catelan, M. Altmann
The recently-discovered lack of close binaries, among extreme horizontal branch (EHB) stars in Galactic globular clusters, has thus far constituted a major puzzle, in view of the fact that blue subdwarf stars - the field counterparts of cluster EHB stars - are well-known to present a high binary fraction. In this Letter, we provide new results that confirm t
Joel Ratsaby
Consider a class $\mH$ of binary functions $h: X\to\{-1, +1\}$ on a finite interval $X=[0, B]\subset \Real$. Define the {\em sample width} of $h$ on a finite subset (a sample) $S\subset X$ as $\w_S(h) \equiv \min_{x\in S} |\w_h(x)|$, where $\w_h(x) = h(x) \max\{a\geq 0: h(z)=h(x), x-a\leq z\leq x+a\}$. Let $\mathbb{S}_\ell$ be the space of all samples in $X$
Volker Eyert, Raymond Fresard, Antoine Maignan
The electronic and magnetic properties of the delafossite CuFeO2 are investigated by means of electronic structure calculations. They are performed using density functional theory in the generalized gradient approximation as well as the new full-potential augmented spherical wave method. The calculations reveal three different spin states at the iron sites.
Alex D. Myasnikov, Alexander Ushakov
The Anshel-Anshel-Goldfeld-Lemieux (abbreviated AAGL) key agreement protocol is proposed to be used on low-cost platforms which constraint the use of computational resources. The core of the protocol is the concept of an Algebraic Eraser (abbreviated AE) which is claimed to be a suitable primitive for use within lightweight cryptography. The AE primitive is
R. L. P. G. Amaral, L. V. Belvedere, K. D. Rothe
We consider the perturbative computation of the N-point function of chiral densities of massive free fermions at finite temperature within the thermofield dynamics approach. The infinite series in the mass parameter for the N-point functions are computed in the fermionic formulation and compared with the corresponding perturbative series in the interaction p
Enhanced thermal stability and spin-lattice relaxation rate of N@C60 inside carbon nanotubes
cond-mat.mtrl-sciS. Toth, D. Quintavalle, B. Nafradi, L. Korecz
We studied the temperature stability of the endohedral fullerene molecule, N@C60, inside single-wall carbon nanotubes using electron spin resonance spectroscopy. We found that the nitrogen escapes at higher temperatures in the encapsulated material as compared to its pristine, crystalline form. The temperature dependent spin-lattice relaxation time, T_1, of
R. B. C. Henry, K. B. Kwitter, R. J. Dufour, J. N. Skinner
We present new HST optical imagery as well as new UV and IR spectroscopic data obtained with the Hubble and Spitzer Space Telescopes, respectively, of the halo planetary nebula DdDm-1. For the first time we present a resolved image of this object which indicates that the morphology of DdDm-1 can be described as two orthogonal elliptical components in the cen
David H. Cohen
OB stars with strong radiation-driven stellar winds and large-scale magnetic fields generate strong and hard X-ray emission via the Magnetically Channeled Wind Shock (MCWS) mechanism. In this brief paper, I describe four separate X-ray diagnostics of the MCWS mechanism in OB stars, with applications to the prototype young O star, theta-1 Ori C.