November 2006 arXiv papers — page 4

Narayan Ganesan, Tzyh Jong Tarn

In this work we propose a novel strategy using techniques from systems theory to completely eliminate decoherence and also provide conditions under which it can be done so. A novel construction employing an auxiliary system, the bait, which is instrumental to decoupling the system from the environment is presented. Our approach to decoherence control in cont

A. I. Nesterov, F. Aceves de la Cruz

We study the geometric phase (GP)in presence of diabolic (DP) and exceptional (EP) points. While the GP associated with the DP is the flux of the Dirac monopole, the GP related to the EP, being complex one, is described by the flux of complex magnetic monopole. For open systems, in week-coupling limit, the leading environment-induced contribution to the real

Changbong Hyeon, George H. Lorimer, D. Thirumalai

The chaperonin GroEL-GroES, a machine which helps some proteins to fold, cycles through a number of allosteric states, the $T$ state, with high affinity for substrate proteins (SPs), the ATP-bound $R$ state, and the $R^{\prime\prime}$ ($GroEL-ADP-GroES$) complex. Structures are known for each of these states. Here, we use a self-organized polymer (SOP) model

Varun Raghunathan, Hagen Renner, Robert R. Rice, Bahram Jalali

We propose a new type of waveguide optical amplifier. The device consists of collinearly propagating pump and amplified Stokes beams with periodic imaging of the Stokes beam due to the Talbot effect. The application of this device as an Image preamplifier for Mid Wave Infrared (MWIR) remote sensing is discussed and its performance is described. Silicon is th

Robert D. Grober, Jacek Cholewicki

It is proposed that aspects of the tempo of the golf swing can be understood in terms of a biomechanical clock. This model explains several aspects of tempo in the golf swing; including total duration of the golf swing, the ratio of backswing to downswing time, and the relative insensitivity of tempo on the length of the golf shot. We demonstrate that this c

Vadim S. Zotev, Andrei N. Matlachov, Petr L. Volegov, Henrik J. Sandin

A seven-channel system capable of performing both magnetoencephalography (MEG) and ultra-low-field magnetic resonance imaging (ULF MRI) is described. The system consists of seven second-order SQUID gradiometers with 37 mm diameter and 60 mm baseline, having magnetic field resolution of 1.2-2.8 fT/rtHz. It also includes four sets of coils for 2-D Fourier imag

M. J. Rayson

A novel low complexity method to perform self-consistent electronic-structure calculations using the Kohn-Sham formalism of density functional theory is presented. Localization constraints are neither imposed nor required thereby allowing direct comparison with conventional cubically scaling algorithms. The method has, to date, the lowest complexity of any a

Sangwoo Ha, Andrey A. Sukhorukov, Yuri S. Kivshar

We study propagation and switching of slow-light pulses in nonlinear couplers with phase-shifted Bragg gratings. We demonstrate that power-controlled nonlinear self-action of light can be used to compensate dispersion-induced broadening of pulses through the formation of gap solitons, to control pulse switching in the coupler, and to tune the propagation vel

R. M. Yulmetyev, D. G. Yulmetyeva, E. V. Khusaenova, P. Hänggi

To discuss the salient role of the statistical memory effects in the human brain functioning we have analyzed a set of stochastic memory quantifiers that reflects the dynamical characteristics of neuromagnetic brain responses to a flickering stimulus of different color combinations from a group of control subjects which is contrasted with those from a patien

Werner Marx, Hermann Schier, Ole Krogh Andersen

As a simple means for comparing and - if possible - predicting scientific impacts of different researchers working in the same field, we suggest comparing their "sales curves". A sales curve is the number of citations of the researcher's papers per year, the citation rate, considered as a function of time. As examples, we present the citation his

Alexander Zaitsev

Two opposing tendencies paradoxically coexist in terrestrial consciousness -- the insistent quest for intelligent signals from other civilizations and the persistent aversion to any attempts to transmit such signals from Earth toward probable fellow intelligent beings. If typical for our entire Universe, such manifestations of intelligence would make the sea

Andreas Aste

The position of the quasielastic peak for (e,e') scattering off 208-Pb extracted from a selected data set measured at Saclay is related to a heuristic theoretical description. An analysis of the data shows that the peak position can be described very accurately by a simple equation in the relevant kinematic region where a pronounced peak is observable. T

Artur M. Ankowski, Jan T. Sobczyk

The argon spectral function is constructed and applied to neutrino-argon cross section computations in the plane wave impulse approximation with the Pauli blocking final state interaction effect taken into account. The approximations of the construction method are critically analyzed using the example of oxygen for which more detailed computations are availa

Spencer R. Klein

The Relativistic Heavy Ion Collider (RHIC) studies nuclear matter under a variety of conditions. Cold nuclear matter is probed with deuteron-gold collisions, while hot nuclear matter(possibly a quark-gluon plasma (QGP)) is created in heavy-ion collisions. The distribution of spin in polarized nucleons is measured with polarized proton collisions, and photopr

Gianluca Caterina, Bruce Boghosian

In this paper we study the problem of the existence of a least-action principle for invertible, second-order dynamical systems, discrete in time and space. We show that, when the configuration space is finite, a least-action principle does not exist for such systems. We dichotomize discrete dynamical systems with infinite configuration spaces into those of f

G. Litak, T. Kaminski, J. Czarnigowski, A. K. Sen

In this paper we analyze the cycle-to-cycle variations of maximum pressure $p_{max}$ and peak pressure angle $α_{pmax}$ in a four-cylinder spark ignition engine. We examine the experimental time series of $p_{max}$ and $α_{pmax}$ for three different spark advance angles. Using standard statistical techniques such as return maps and histograms we show that de

S. Twareque Ali, Miroslav Engliš

We generalize some earlier results on a Berezin-Toeplitz type of quantization on Hilbert spaces built over certain matrix domains. In the present, wider setting, the theory could be applied to systems possessing several kinematic and internal degrees of freedom. Our analysis leads to an identification of those observables, in this general context, which admi

Dan Coman, Evgeny A. Poletsky

In this paper we study the consequences of overinterpolation, i.e., the situation when a function can be interpolated by polynomial, or rational, or algebraic functions in more points that normally expected. We show that in many cases such a function has specific forms.

Makhlouf Derridj, Bernard Helffer

For about twenty five years it was a kind of folk theorem that complex vector-fields defined on $Ω\times \mathbb R_t$ (with $Ω$ open set in $\mathbb R^n$) by $$ L_j = \frac{\partial}{\partial t_j} + i \frac {\partial ϕ}{\partial t_j}(\t) \frac{\partial}{\partial x}, j=1,..., n, \t\in Ω, x\in \mathbb R ,$$ with $ϕ$ analytic, were subelliptic as soon as they w

Valerie Hower

We present a counterexample to the conjecture of Bihan, Franz, McCrory, and van Hamel concerning the maximality of toric varieties. There exists a six dimensional projective toric variety X with the sum of the mod 2 Betti numbers of X(R) strictly less than the sum of the mod 2 Betti numbers of X(C).

A. Bernini, m. Bouvel, L. Ferrari

In the last decade a huge amount of articles has been published studying pattern avoidance on permutations. From the point of view of enumeration, typically one tries to count permutations avoiding certain patterns according to their lengths. Here we tackle the problem of refining this enumeration by considering the statistics "first/last entry". We

Huah Chu, Shou-Jen Hu, Ming-chang Kang, Jiping Zhang

Let K be an arbitrary field. We will determine explicitly all the nontrivial finite groups of essential dimension one over K.

Huaiyu Jian, Binheng Song

Consider the anisotropic porous medium equation, $u_t=\sum\limits_{i=1}^n(u^{m_i})_{x_ix_i},$ where $m_i>0, (i=1,2,...,n)$ satisfying $\min\limits_{1\le i\le n}\{m_i\}\le 1,$ $\sum\limits_{i=1}^nm_i>n-2,$ and $\max\limits_{1\le i\le n}\{m_i\}\le \frac{1}{n}(2+\sum\limits_{i=1}^nm_i).$ Assuming that the initial data belong only to $L^1(\Re^n)$, we establish t

Bo Guan, Huaiyu Jian, Richard M. Schoen

We are concerned with spacelike convex hypersurfaces of positive constant (K-hypersurfaces) or prescribed Gauss curvature in Minkowski space. Our main purpose is to study entire solutions as well as the Dirichlet problem in bounded domains of the related Monge-Ampere equation.

Huaiyu Jian

In this paper, we study the existence, uniqueness and asymptotic behavior of rotationally symmetric translating solitons of the mean curvature flow in Minkowski space. We also study the asymptotic behavior and the strict convexity of general solitons of such flows.

Huaiyu Jian

In this paper, we study the Hessian equation with infinite Dirichlet (blow-up) boundary value conditions. Using radial functions and techniques of ordinary differential inequality, we construct various barrier functions (super-solution and sub-solution). Existence and non-existence theorems are proved by those barriers, maximum principle and theory of viscou

Yanan Liu, Huaiyu Jian

In this paper, we study the evolution of submannifold moving by mean curvature minus a external force field. We prove that the flow has a long-time smooth solution for all time under almost optimal conditions. Those conditions are that the second fundamental form on the initial submanifolds is not too large, the external force field, with its any order deriv

Jiayang Sun, Anirban DasGupta, Vince Melfi, Connie Page

There have been extensive developments recently in modern nonparametric inference and modeling. Nonparametric and semi-parametric methods are especially useful with large amounts of data that are now routinely collected in many areas of science. Probability and stochastic modeling are also playing major new roles in scientific applications. This refereed spe

D. A. Stepanov

The dual complex can be associated to any resolution of singularities whose exceptional set is a divisor with simple normal crossings. It generalizes to higher dimensions the notion of the dual graph of a resolution of surface singularity. The homotopy type of the dual complex does not depend on the choice of a resolution and thus can be considered as an inv

Pekka Koskela, Eero Saksman

We establish simple pointwise characterizations of functions in the Hardy-Sobolev spaces within the range n/(n+1)<p <=1. In addition, classical Hardy inequalities are extended to the case p <= 1.

Boju Jiang, Shicheng Wang, Hao Zheng, Qing Zhou

Solenoids are ``inverse limits&#39;&#39; of the circle, and the classical knot theory is the theory of tame embeddings of the circle into the 3-space. We give some general study, including certain classification results, of tame embeddings of solenoids into the 3-space as the ``inverse limits&#39;&#39; of the tame embeddings of the circle. Some applications

Toshio Oshima

We study a system of partial differential equations defined by commuting family of differential operators with regular singularities. We construct ideally analytic solutions depending on a holomorphic parameter. We give some explicit examples of differential operators related to $SL(n,\mathbb R)$ and completely integrable quantum systems.

John Rhodes, Benjamin Steinberg

We prove that the class of closed subgroups of free profinite monoids is precisely the class of projective profinite groups. In particular, the profinite groups associated to minimal symbolic dynamical systems by Almeida are projective. Our result answers a question raised by Lubotzky during the lecture of Almeida at the Fields Workshop on Profinite Groups a

Emma Hoarau, Claire David

A Mathematica based program has been elaborated in order to determine the symmetry group of a finite difference equation, by means of its differential representation. The package provides functions which enable us to solve the determining equations of the related Lie group

Robin Hartshorne

We extend the theory of generalized divisors so as to work on any scheme $X$ satisfying the condition $S_2$ of Serre. We define a generalized notion of Gorenstein biliaison for schemes in projective space. With this we give a new proof in a stronger form of the theorem of Gaeta, that standard determinantal schemes are in the Gorenstein biliaison class of a c

Angel Sanchez, Alejandro Ayala, Gabriella Piccinelli

We study the symmetry breaking phenomenon in the standard model during the electroweak phase transition in the presence of a constant hypermagnetic field. We compute the finite temperature effective potential up to the contribution of ring diagrams in the weak field, high temperature limit and show that under these conditions, the phase transition becomes st

Roman V. Buniy, Thomas W. Kephart

In classical mechanics, an action is defined only modulo additive terms which do not modify the equations of motion; in certain cases, these terms are topological quantities. We construct an infinite sequence of higher order topological actions and argue that they play a role in quantum mechanics, and hence can be accessed experimentally.

Roman V. Buniy, Thomas W. Kephart

Gaussian linking of a semiclassical path of a charged particle with a magnetic flux tube is responsible for the Aharonov-Bohm effect, where one observes interference proportional to the magnitude of the enclosed flux. We construct quantum mechanical wave functions where semiclassical paths can have second order linking to two magnetic flux tubes, and show th

Vladimir Cuesta, Merced Montesinos, Jose David Vergara

Some very simple models of gauge systems with noncanonical symplectic structures having $sl(2,r)$ as the gauge algebra are given. The models can be interpreted as noncommutative versions of the usual $SL(2,\mathbb{R})$ model of Montesinos-Rovelli-Thiemann. The symplectic structures of the noncommutative models, the first-class constraints, and the equations

Oliver J. Rosten

In the context of very general exact renormalization groups, it will be shown that, given a vertex expansion of the Wilsonian effective action, remarkable progress can be made without making any approximations. Working in QCD we will derive, in a manifestly gauge invariant way, an exact diagrammatic expression for the expectation value of an arbitrary gauge

Hitoshi Nishino, Subhash Rajpoot

Consistent interactions of spin 3/2 field that realize a nilpotent spinorial symmetry are presented. Based on our previous results on purely bosonic non-Abelian tensor with consistent interactions, we present a new system for interacting spin 3/2 field that realizes the nilpotent fermionic symmetry.

Yogesh K. Srivastava

We study perturbations of supertube in KK monopole background, at both DBI and supergravity levels. We analyse both NS1-P as well as D0-F1 duality frames and study different profiles. This illuminates certain aspects of bound states of KK monopoles with supertubes.

Daniel Boer

We consider forward pion production in p p collisions at RHIC energies,which probes the so-called Extended Geometric Scaling region. Upon inclusion of small-x effects via an anomalous dimension within the Color Glass Condensate formalism at leading order in alpha_s, a good description of the cross section as a function of the transverse momentum of the produ

T. Hahn, S. Heinemeyer, W. Hollik, H. Rzehak

Large higher-order corrections enter the Higgs boson sector of the MSSM via Higgs-boson self-energies. Their effects have to be taken into account for the correct treatment of loop-corrected Higgs-boson mass eigenstates as external (on-shell) or internal particles in Feynman diagrams. We review how the loop corrections, including momentum dependence and imag

S. Heinemeyer, W. Hollik, D. Stockinger, A. M. Weber

We review the currently most accurate evaluation of the W boson mass, M_W, in the Minimal Supersymmetric Standard Model (MSSM). It consists of a full one-loop calculation, including the complex phase dependence, all available MSSM two-loop corrections as well as the full Standard Model result. We analyse the impact of the phases in the scalar quark sector on

Arnon Dar, A. De Rujula

A.M. Hillas, in a review of the origins of cosmic rays, has recently criticized the &#34;cannonball&#34; (CB) model of cosmic rays and gamma-ray bursts. We respond to this critique and take the occasion to discuss the crucial question of particle acceleration in the CB model and in the generally accepted models. We also summarize our claims concerning the CB

Wilfried Buchmuller

We study implications of thermal leptogenesis for the superparticle mass spectrum. A consistent picture is obtained if the lightest superparticle is the gravitino, which can be the dominant component of cold dark matter. In the case of a long-lived charged scalar lepton as next-to-lightest superparticle, supergravity can be tested at the next generation of c

A. Bhattacharya, B. Chakrabarti, S. Mani, S. N. Banerjee

The properties of the Theta^{+} and Xi^{--}_{3/2} exotic baryons have been investigated in the framework of diquark- diquark-antiquark system. A model for diquark suggested in an analogy with the quasi-particle in a crystal lattice has been used. The mass of the exotics have been computed. The Decay width of the Theta^{+} has been estimated to be ~ 11 MeV us

Bastian Kubis, Eike H. Müller, Jürg Gasser, Martin Schmid

We re-investigate the radiative charged kaon decay K+- --> pi0 e+- nu_e gamma in chiral perturbation theory, merging the chiral expansion with Low&#39;s theorem. We thoroughly analyze the precision of the predicted branching ratio relative to the non-radiative decay channel. Structure dependent terms and their impact on differential decay distributions are i

A. I. Ahmadov, I. Boztosun, A. Soylu, E. A. Dadashov

In this article, we investigate the contribution of the high twist Feynman diagrams to the large $p_{T}$ single pseudoscalar and vector mesons inclusive production cross section in two-photon collisions and we present the general formulae for the high and leading twist differential cross sections. The pion wave function where two non-trivial Gegenbauer coeff

H. M. Chan, S. T. Tsou

An earlier suggestion that scalar fields in gauge theory may be introduced as frame vectors or vielbeins in internal symmetry space, and so endowed with geometric significance, is here sharpened and refined. Applied to a $u(1) \times su(2)$ theory this gives exactly the Higgs structure of the standard electroweak theory. Applied to an $su(3)$ theory, it give

Alexey A Petrov

The motivation most often cited in searches for D0-anti-D0 mixing and CP-violation in charm system lies with the possibility of observing a signal from New Physics which dominates that from the Standard Model. We review recent theoretical predictions and experimental constraints on D0-anti-D0 mixing parameters, concentrating on possible effects of New Physic

Giacomo Cacciapaglia, Csaba Csáki, Guido Marandella, John Terning

We present a class of models that contains Randall-Sundrum and Higgsless models as limiting cases. Over a wide range of the parameter space WW scattering is mainly unitarized by Kaluza-Klein partners of the W and Z, and the Higgs particle has suppressed couplings to the gauge bosons. Such a gaugephobic Higgs can be significantly lighter than the 114 GeV LEP

T. A. -Kh. Aushev

We report the recent results of a search for the decay B- --> tau- anti-nu_tau, observations of new resonances X, Y and Z, and the first results from Upsilon(5S) data collected with the Belle detector at KEKB e+e- collider.

The Belle Collaboration, A. Kuzmin

We report the results of a study of neutral B meson decays to the D^0 pi+ pi- final state, where the D^0 is fully reconstructed. The results are obtained from an event sample containing 388 million BB-bar -meson pairs collected in the Belle experiment at the KEKB e^+e^- collider. The total branching fraction of the three-body decay B(bar{B}^0 -> D^0 pi^+ pi^

M R Setare

The Casimir stress on two parallel plates in a de Sitter background corresponding to different metric signatures and cosmological constants is calculated for massless scalar fields satisfying Robin boundary conditions on the plates. Our calculation shows that for the parallel plates with false vacuum between and true vacuum outside, the total Casimir pressur

Francisco S. N. Lobo

We explore the possibility that traversable wormholes be supported by specific equations of state responsible for the present accelerated expansion of the Universe, namely, phantom energy, the generalized Chaplygin gas, and the van der Waals quintessence equation of state.

Belynda Brahimi, Eric Rondeau, Christophe Aubrun

The distributed control systems are more and more used in many industrial applications. These systems are often referred as &#34;Networked control systems&#34;. The goal of this paper is to show the network influence on feedback control systems. Two networks are considered: Switched Ethernet network and CAN fieldbus. The first one represents the non determin

Manuel Loth, Philippe Preux

This paper addresses the issue of policy evaluation in Markov Decision Processes, using linear function approximation. It provides a unified view of algorithms such as TD(lambda), LSTD(lambda), iLSTD, residual-gradient TD. It is asserted that they all consist in minimizing a gradient function and differ by the form of this function and their means of minimiz

K. A. Hawick, H. A. James

We have investigated the anomalous scaling behaviour of the Ising model on small-world networks based on 2- and 3-dimensional lattices using Monte Carlo simulations. Our main result is that even at low $p$, the shift in the critical temperature $ΔT_c$ scales as $p^{s}$, with $s \approx 0.50$ for 2-D systems, $s \approx 0.698$ for 3-D and $s \approx 0.75$ for

Pouyan Ghaemi, T. Senthil

Conventional heavy Fermi liquid phases of Kondo lattices involve the formation of a &#34;Kondo singlet&#34; between the local moments and the conduction electrons. This Kondo singlet is usually taken to be in an internal s-wave angular momentum state. Here we explore the possibility of phases where the Kondo singlet has internal angular momentum that is d-wa

J. H. Shim, K. Haule, G. Kotliar

Plutonium displays phase transitions with enormous volume differences among its phases and both its Pauli like magnetic susceptibility and resistivity are an order of magnitude larger than those of simple metals. Curium is also highly resistive but its susceptibility is Curie-like at high temperatures and orders antiferromagnetically at low temperatures. The

F. Fumarola, Y. Ahmadian, I. L. Aleiner, B. L. Altshuler

We predict a nonequilibrium critical phenomenon in the space-time density evolution of a fermionic gas above the temperature of transition into the superfluid phase. On the BCS side of the BEC-BCS crossover, the evolution of a localized density disturbance exhibits a negative echo at the point of the initial inhomogeneity. Approaching the BEC side, this effe

Kevin Wood, C. Van den Broeck, R. Kawai, Katja Lindenberg

We study synchronization in populations of phase-coupled stochastic three-state oscillators characterized by a distribution of transition rates. We present results on an exactly solvable dimer as well as a systematic characterization of globally connected arrays of N types of oscillators (N=2, 3, 4) by exploring the linear stability of the nonsynchronous fix

E. Rousseau, Y. Mukharsky, D. Ponarine, O. Avenel

We have observed trapping of electrons in an electrostatic trap formed over the surface of liquid helium-4. These electrons are detected by a Single Electron Transistor located at the centre of the trap. We can trap any desired number of electrons between 1 and $\sim 30$. By repeatedly ($\sim 10^3-10^4$ times) putting a single electron into the trap and lowe

R. Silva

We have investigated the proof of the $H$ theorem within a manifestly covariant approach by considering the relativistic statistical theory developed in [G. Kaniadakis, Phy. Rev. E {\bf 66}, 056125, 2002; {\it ibid.} {\bf 72}, 036108, 2005]. As it happens in the nonrelativistic limit, the molecular chaos hypothesis is slightly extended within the Kaniadakis

A. N. Grigorenko, K. S. Novoselov, D. J. Mapps

We report a room temperature tunneling anisotropic magnetoresistance in Co/Al2O3/NiFe junctions containing magnetic electrodes oxidized prior to forming the Al2O3 layer. A significant change in a tunnel magnetoresistance is observed when the layer magnetizations are rotated collinearly in the junction plane by an applied external field. The angular dependenc

S. Corni

ElectroChemical Scanning Tunneling Microscopy (ECSTM) is gaining popularity as a tool to implement proof-of-concept single (bio)molecular transistors. The understanding of such systems requires a discussion of the mechanism of the electrochemical current gating, which is intimately related to the electrostatic potential distribution in the tip-substrate gap

G. Litak, M. Krawiec

We study the properties of a quantum impurity embedded in a superconducting host of a d-wave symmetry. The superconductor is described by the extended negative $U$ Hubbard model while the impurity introduces a repulsive interaction to the system around the central site. We discuss the influence of this repulsion on the local properties (density of states, el

Fabrizio Dolcini, Francesco Giazotto

We investigate the DC Josephson effect in a superconductor-normal metal-superconductor junction where the normal region consists of a ballistic ring. We show that a fully controllable $π$-junction can be realized through the electro-magnetostatic Aharonov-Bohm effect in the ring. The sign and the magnitude of the supercurrent can be tuned by varying the magn

Tamas Vicsek, Andras Czirok, Eshel Ben-Jacob, Inon Cohen

A simple model with a novel type of dynamics is introduced in order to investigate the emergence of self-ordered motion in systems of particles with biologically motivated interaction. In our model particles are driven with a constant absolute velocity and at each time step assume the average direction of motion of the particles in their neighborhood with so

Andras Czirok, Tamas Vicsek

We discuss biologically inspired, inherently non-equilibrium self-propelled particle models, in which the particles interact with their neighbours by choosing at each time step the local average direction of motion. We summarize some of the results of large scale simulations and theoretical approaches to the problem.

Andras Czirok, H. Eugene Stanley, Tamas Vicsek

We study a biologically inspired, inherently non-equilibrium model consisting of self-propelled particles. In the model, particles move on a plane with a velocity of constant magnitude; they locally interact with their neighbors by choosing at each time step a velocity direction equal to the average direction of their neighbors. Thus, in the limit of vanishi

S. H. Abedinpour, M. Polini, Gao Xianlong, M. P. Tosi

Motivated by current interest in strongly correlated quasi-one-dimensional (1D) Luttinger liquids subject to axial confinement, we present a novel density-functional study of few-electron systems confined by power-low external potentials inside a short portion of a thin quantum wire. The theory employs the 1D homogeneous Coulomb liquid as the reference syste

Guan-Fang Wang, Li-Bin Fu, Jie Liu

We investigate the spin tunnelling of spin-1 Bose-Einstein condensates in a linearly sweeping magnetic field with a mean-field treatment. We focus on the two typical alkali Bose atoms $^{87}Rb$ and $^{23}Na$ condensates and study their tunnelling dynamics according to different sweeping rates of external magnetic fields. In the adiabatic (i.e., slowly sweepi

Arkady Shekhter, Alexander M. Finkel&#39;stein

The recently measured spin susceptibility of the two dimensional electron gas exhibits a strong dependence on temperature, which is incompatible with the standard Fermi liquid phenomenology. Here we show that the observed temperature behavior is inherent to ballistic two dimensional electrons. Besides the single-particle and collective excitations, the therm

Kurtis A. Williams, Michael Bolte

We present photometric and spectroscopic studies of the white dwarf (WD) populations in the intermediate-age open clusters NGC 6633 and NGC 7063 as part of the ongoing Lick-Arizona White Dwarf Survey (LAWDS). Using wide-field CCD imaging, we locate 41 candidate WDs in the two cluster fields: 32 in NGC 6633, and 9 in NGC 7063. Spectroscopic observations confi

Nahum Arav, Jack R. Gabel, Kirk T. Korista, Jelle S. Kaastra

We present the first reliable determination of chemical abundances in an AGN outflow. The abundances are extracted from the deep and simultaneous FUSE and HST/STIS observations of Mrk 279. This data set is exceptional for its high signal-to-noise, unblended doublet troughs and little Galactic absorption contamination. These attributes allow us to solve for t

Vasiliki Pavlidou, Brian D. Fields

We present an analytical description of the energetics of the population of cosmic accretion shocks, for a concordance cosmology. We calculate how the shock-processed accretion power and mass current are distributed among different shock Mach numbers, and how they evolve with cosmic time. We calculate the cumulative energy input of cosmic accretion shocks of

Patrick B. Hall

I report the discovery of blueshifted broad absorption line (BAL) troughs in at least six transitions of the Balmer series of hydrogen (Hbeta to H9) and in CaII, MgII and excited FeII in the quasar SDSS J125942.80+121312.6. This is only the fourth active galactic nucleus known to exhibit Balmer absorption, all four in conjunction with low-ionization BAL syst

Keren Sharon, A. Gal-Yam, D. Maoz, M. Donahue

We describe our ongoing program designed to measure the SN-Ia rate in a sample of massive z=0.5-0.9 galaxy clusters. The SN-Ia rate is a poorly known observable, especially at high z, and in cluster environments. The SN rate and its redshift dependence can serve as powerful discrimiminants for a number of key issues in astrophysics and cosmology. Our observa

Avishay Gal-Yam, S. B. Cenko, D. B. Fox, D. C. Leonard

We present preliminary results from the Caltech Core-Collapse Project (CCCP), a large observational program focused on the study of core-collapse SNe. Uniform, high-quality NIR and optical photometry and multi-epoch optical spectroscopy have been obtained using the 200&#39;&#39; Hale and robotic 60&#39;&#39; telescopes at Palomar, for a sample of 50 nearby c

H. W. W. Spoon, J. A. Marshall, J. R. Houck, M. Elitzur

We present a new diagnostic diagram for mid-infrared spectra of infrared galaxies based on the equivalent width of the 6.2 micron PAH emission feature and the strength of the 9.7 micron silicate feature. Based on the position in this diagram we classify galaxies into 9 classes ranging from continuum-dominated AGN hot dust spectra and PAH-dominated starburst

M. Goto, Sun Kwok, H. Takami, M. Hayashi

We present 3 um spectroscopy of the carbon-rich proto-planetary nebulae IRAS 04296+3429 and IRAS 05341+0852 conducted with the adaptive optics system at the Subaru Telescope. We utilize the nearly diffraction-limited spectroscopy to probe the spatial extent of the hydrocarbon dust emitting zone. We find a hydrocarbon emission core extending up to 100--160 ma

Francis Halzen

Although kilometer-scale neutrino detectors such as IceCube are discovery instruments, their conceptual design is very much anchored to the observational fact that Nature produces protons and photons with energies in excess of 10^20 eV and 10^13 eV, respectively. The puzzle of where and how Nature accelerates the highest energy cosmic particles is unresolved

A. Cattaneo, R. Teyssier

We use three-dimensional high-resolution adaptive-mesh-refinement simulations to investigate if mechanical feedback from active galactic nucleus jets can halt a massive cooling flow in a galaxy cluster and give rise to a self-regulated accretion cycle. We start with a 3 x 10^9MSun black hole at the centre of a spherical halo with the mass of the Virgo cluste

Lily Schrempp

We analyze the prospects for testing the cosmic neutrino background and its interpretation as source of Neutrino Dark Energy with the radio telescope LOFAR.

J. A. R. Cembranos, A. Dobado, A. L. Maroto

In extra-dimensional brane-world models with low tension, brane excitations provide a natural WIMP candidate for dark matter. Taking into account the various constraints coming from colliders, precision observables and direct search, we explore the possibilities for indirect search of the galactic halo branons through their photon producing annihilations in

Michael A. Nowak

I review here some of the open questions regarding the geometry and emission mechanisms of galactic black hole candidates. For hard states, I concentrate on the perspective of ``disk+Compton coronae&#39;&#39; models (for discussions of jet models, see the papers by Sera Markoff). Specifically, I discuss the implications from our 10 year long RXTE monitoring

D. Dewey, T. DeLaney, J. S. Lazendic

Chandra High-Energy Transmission Grating (HETG) X-ray spectra are extracted from 17 bright, narrow regions of Cas A and provide unique measurements of their kinematic and plasma states. From the dominant emission lines, e.g. He-like Si, we derive accurate Doppler shifts in the range -2500 to +4000 km/s; these agree well with transverse-velocity measurements

R. Plume, G. A. Fuller, F. Helmich, F. F. S. van der Tak

Stars form in the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes which can reveal the dynamics, physics, chemistry and evolution of these regions, but our understanding of the molecular inventory of sources and how this is related to their physical state and evolution is rudimentary and incomplete. The Spectra

P. -E. Tremblay, P. Bergeron

We review the available near- and mid- infrared photometry data sets for white dwarfs from the Two Micron All-Sky Survey (2MASS) Point Source Catalog and the Spitzer Space Telescope. These data sets have been widely used to search for white dwarfs with an infrared excess as well as to characterize the atmosphere of cool white dwarfs. We evaluate the reliabil

Gaetano Lambiase, Subhendra Mohanty

We introduce a dimension five CP violating coupling between the Ricci scalar and fermions. This operator splits the energy level between neutrinos and anti-neutrinos and can generate a lepton-asymmetry in the the radiation era if heavy Majorana neutrinos decouple at the GUT scale. This operator can also generate a lepton asymmetry during warm inflation if th

P. Bergeron, A. Gianninas, S. Boudreault

We discuss some of our current knowledge of the mass distribution of DA and non-DA stars using various methods for measuring white dwarf masses including spectroscopic, trigonometric parallax, and gravitational redshift measurements, with a particular emphasis on the problems encountered at the low end of the cooling sequence where energy transport by convec

M. B. N. Kouwenhoven, A. G. A. Brown, L. Kaper

We present JHK observations of 22 intermediate-mass stars in Sco OB2, obtained with VLT/NACO. The survey was performed to determine the status of (sub)stellar candidate companions of A and late-B members. The distinction between companions and background stars is by a comparison with isochrones and statistical arguments. We are sensitive to companions in the

Lifan Wang, Dietrich Baade, Ferdinando Patat

Even at extragalactic distances, the shape of supernova ejecta can be effectively diagnosed by spectropolarimetry. We present here results for 17 Type Ia supernovae that allow a statistical study of the correlation among the geometric structures and other observable parameters of Type Ia supernovae. These observations suggest that their ejecta typically cons

Bartosz Fornal, Douglas L. Tucker, J. Allyn Smith, Sahar S. Allam

We continue our series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u&#39;g&#39;r&#39;i&#39;z&#39; filter system. The entire observed sample covered more than 100 clusters, but here we present data only on NGC 188, which is one of the oldest open clusters known in the Milky

P. -E. Tremblay, P. Bergeron

We review the available near- and mid-infrared photometry for white dwarfs obtained from the Two Micron All-Sky Survey (2MASS) and by the Spitzer Space Telescope. Both data sets have recently been used to seek white dwarfs with infrared excesses due to the presence of unresolved companions or circumstellar disks, and also to derive the atmospheric parameters

S. P. Rajaguru, K. Sankarasubramanian, R. Wachter, P. H. Scherrer

We show that the use of Doppler shifts of Zeeman sensitive spectral lines to observe wavesn in sunspots is subject to measurement specific phase shifts arising from, (i) altered height range of spectral line formation and the propagating character of p mode waves in penumbrae, and (ii) Zeeman broadening and splitting. We also show that these phase shifts dep

Terry Bridges, Katherine Rhode, Steve Zepf, Ken Freeman

We present new velocities for 62 globular clusters in M104 (NGC 4594, the Sombrero Galaxy), 56 from 2dF on the AAT and 6 from Hydra on WIYN. Combined with previous data, we have a total sample of 108 M104 globular cluster velocities, extending to 20 arcmin radius (~60 kpc), along with BVR photometry for each of these. We use this wide-field dataset to study