April 2009 arXiv papers — page 44

J. Hamann, S. Hannestad, G. G. Raffelt, Y. Y. Y. Wong

We explore the cosmological sensitivity to the amplitude of isocurvature fluctuations that would be caused by axions in the "anthropic window" where the axion decay constant f_a >> 10^12 GeV and the initial misalignment angle Theta_i << 1. In a minimal Lambda-CDM cosmology extended with subdominant scale-invariant isocurvature fluctuations, existing data con

Jorge Villa-Vargas, Isaac Shlosman, Clayton Heller

We construct and evolve families of steady-state models of stellar disks embedded in live DM halos, in order to study the dynamical and secular phases of bar evolution. These models are tested against those published in the literature in order to extend them and include the gaseous component in the follow up paper. We are interested in the angular momentum (

Ivan Gordeli, Peter Koroteev

Recently a family of solutions of Einstein equations in backgrounds with broken Lorentz invariance was found ArXiv:0712.1136. We show that the gravitational solution recently obtained by Kachru, Liu and Mulligan in ArXiv:0808.1725 is a part of the former solution which was derived earlier in the framework of extra dimensional theories. We show how the energy

S. W. Randall, C. Jones, M. Markevitch, E. L. Blanton

We present results from Chandra observations of the galaxy pair and associated galaxy group NGC 5098, and find evidence for both gas sloshing and AGN heating. The X-ray brightness images show diffuse emission with a spiral structure, centered on NGC 5098a, and a sharp edge in the diffuse emission surrounding much of the galaxy at about 30 kpc. The spiral str

Adriana Pálffy, Christoph H. Keitel, Jörg Evers

Generation of single-photon entanglement is discussed in nuclear forward scattering. Using successive switchings of the direction of the nuclear hyperfine magnetic field, the coherent scattering of photons on nuclei is controlled such that two signal pulses are generated out of one initial pump pulse. The two time-resolved correlated signal pulses have diffe

D. Dudal, S. P. Sorella, N. Vandersickel, H. Verschelde

We aim to offer a kind of unifying view on two popular topics in the studies of nonperturbative aspects of Yang-Mills theories in the Landau gauge: the so-called Gribov-Zwanziger approach and the Kugo-Ojima confinement criterion. Borrowing results from statistical thermodynamics, we show that imposing the Kugo-Ojima confinement criterion as a boundary condit

Łukasz Bolikowski

The interlanguage links in Wikipedia connect pages on the same subject written in different languages. In theory, each connected component should be a clique and cover one topic. However, incoherent edits and obvious mistakes result in topic coalescence, yielding a non-trivial topology that is studied in this paper. We show that the component size distributi

Qusay S. A. Al-Zamil

In this paper, we construct the Hankel determinant representation of the rational solutions for the fifth Painlevé equation through the Umemura polynomials. Our construction gives an explicit form of the Umemura polynomials $σ_{n}$ for $ n\geq 0$ in terms of the Hankel Determinant formula. Besides, We compute the generating function of the entries in terms o

Michael Blum

Approximate Bayesian Computation is a family of likelihood-free inference techniques that are well-suited to models defined in terms of a stochastic generating mechanism. In a nutshell, Approximate Bayesian Computation proceeds by computing summary statistics s_obs from the data and simulating summary statistics for different values of the parameter theta. T

Pan-Jun Kim, Dong-Yup Lee, Hawoong Jeong

Glycosylation is a highly complex process to produce a diverse repertoire of cellular glycans that are attached to proteins and lipids. Glycans are involved in fundamental biological processes, including protein folding and clearance, cell proliferation and apoptosis, development, immune responses, and pathogenesis. One of the major types of glycans, N-linke

Roman Mikhailov, Inder Bir S. Passi

We consider limits over categories of extensions and show how certain well-known functors on the category of groups turn out as such limits. We also discuss higher (or derived) limits over categories of extensions.

Aybike Catal-Ozer, Nihat Sadik Deger

We construct new M-theory solutions starting from those that contain 5 U(1) isometries. We do this by reducing along one of the 5-torus directions, then T-dualizing via the action of an O(4,4) matrix and lifting back to 11-dimensions. The particular T-duality transformation is a sequence of O(2,2) transformations embedded in O(4,4), where the action of each

Nadir Farhi

This is a technical note where we solve the additive eigenvalue problem associated to a dynamics of a 2D-traffic system. The traffic modeling is not explained here. It is available in \cite{Far08}. It consists of a microscopic road traffic model of two circular roads crossing on one junction managed with the priority-to-the-right rule. It is based on Petri n

Aljoscha Maria Hahn, Holger Then

A powerful and well-established tool for free-energy estimation is Bennett&#39;s acceptance ratio method. Central properties of this estimator, which employs samples of work values of a forward and its time reversed process, are known: for given sets of measured work values, it results in the best estimate of the free-energy difference in the large sample li

Juan-Pablo Ortega, Rainer Pullirsch, Josef Teichmann, Julian Wergieluk

We provide a new dynamic approach to scenario generation for the purposes of risk management in the banking industry. We connect ideas from conventional techniques -- like historical and Monte Carlo simulation -- and we come up with a hybrid method that shares the advantages of standard procedures but eliminates several of their drawbacks. Instead of conside

Alejandro Jenkins

In this essay we review the central difficulty in formulating a viable quantum field theory in which gravity is emergent at low energies, rather than mediated by a fundamental gauge field. The Weinberg-Witten theorem forbids spin 2 massless modes from carrying Lorentz covariant stress-energy. In General Relativity the stress-energy is not covariant because i

David I. Stewart

Let $G$ be the simple algebraic group $SL_2$ defined over an algebraically closed field $K$ of characteristic $p>0$. In this paper, we find the second cohomology of all irreducible representations of $G$

P. J. van Zwol, G. Palasantzas, J. Th. M. DeHosson

In this work we concentrate on an experimental validation of the Lifshitz theory for van der Waals and Casimir forces in gold-alcohol-glass systems. From this theory weak dispersive forces are predicted when the dielectric properties of the intervening medium become comparable to one of the interacting surfaces. Using inverse colloid probe atomic force micro

Lydia Bieri

In this paper, we sketch the proof of the extension of the stability theorem of the Minkowski space in General Relativity done explicitly in previous work by the present author. We discuss solutions of the Einstein vacuum (EV) equations. We solve the Cauchy problem for more general, asymptotically flat initial data than in the pioneering work `The Global Non

Antoine Mellet, Julien Vovelle

We study a class of mean curvature equations $-\mathcal Mu=H+λu^p$ where $\mathcal M$ denotes the mean curvature operator and for $p\geq 1$. We show that there exists an extremal parameter $λ^*$ such that this equation admits a minimal weak solutions for all $λ\in [0,λ^*]$, while no weak solutions exists for $λ>λ^*$ (weak solutions will be defined as critica

B. J. Powell, J. Merino, Ross H. McKenzie

We introduce a strongly correlated mean-field theory of the ionic Hubbard model on the triangular lattice with alternating stripes of site energy using Barnes-Coleman slave bosons. We study the paramagnetic phases of this theory at three quarters filling, where it is a model of Na_0.5CoO_2, Rb_0.5CoO_2, and K_0.5CoO_2. This theory has two bands of fermionic

Firouz Khezri

Isoparametric hypersurfaces and their application to special geometries

Vincenzo Calò, Gianni Tallarita, Steven Thomas

Starting from the action of two coincident non-BPS D9-branes, we investigate kink configurations of the U(2) matrix tachyon field. We consider both Str and Tr prescriptions for the trace over gauge indices of the non-BPS action. Non-abelian tachyon condensation in the theory with Tr prescription, and the resulting fluctuations about the kink profile, are sho

D. A. Pigg, A. S. Umar, V. E. Oberacker

We discuss three practical methods for performing Eulerian rotations of Slater determinants in a three-dimensional Cartesian geometry. In addition to the straightforward application of the active form of the quantum mechanical rotation operator, we introduce two methods using a passive position-space rotation followed by an active spin-space rotation, one af

Zhaoxia Heng, Gongru Lu, Lei Wu, Jin Min Yang

In the minimal supersymmetric standard model the R-parity violating interactions can trigger various exotic three-body decays for the top quark, which may be accessible at the LHC. In this work we examine the R-violating decays t-> c X_1 X_2, which include the tree-level processes t-> c l^-_i l^+_j (l_i=e, mu, tau) and t->c d_i \bar{d}_j (d_i=d, s, b), as we

Georg Moser, Andreas Schnabl

We study the derivational complexity induced by the dependency pair method, enhanced with standard refinements. We obtain upper bounds on the derivational complexity induced by the dependency pair method in terms of the derivational complexity of the base techniques employed. In particular we show that the derivational complexity induced by the dependency pa

Alexandre Dezotti

We show that the Arnold tongues of the family of double standard maps f_{a,b}(x) = 2x + a + (b/pi) sin(2 pi x), are connected. This proof is accomplished in the complex domain by means of quasiconformal techniques and depends partly upon the fact that the complexification of f_{a,b} has only one critical point taking symmetry into account.

Eoin Ó Colgáin, Hossein Yavartanoo

We extend the search for supergravity solution duals of non-relativistic $d=3$ CFTs to $d=11$ supergravity. We consider the internal space to be an $S^2$ bundle over a product base: $S^2 \times S^2$ and $S^2 \times T^2$. For purely M-theoretic $S^2 \times S^2$, we find only magnetic fluxes preserving two supersymmetries. $S^2 \times T^2$ is far richer admitt

J. E. Geach, D. M. Alexander, B. D. Lehmer, Ian Smail

We present the results of a 400ks Chandra survey of 29 extended Ly-alpha emitting nebulae (Ly-alpha Blobs, LABs) in the z=3.09 proto-cluster in the SSA22 field. We detect luminous X-ray counterparts in five LABs, implying a large fraction of active galactic nuclei (AGN) in LABs, f_AGN = 17% down to L_2-32keV ~ 10^44 erg/s. All of the AGN appear to be heavily

Jean Bertoin

We are interested in the genealogical structure of alleles for a Bienaymé-Galton-Watson branching process with neutral mutations (infinite alleles model), in the situation where the initial population is large and the mutation rate small. We shall establish that for an appropriate regime, the process of the sizes of the allelic sub-families converges in dist

Anne-Laure Fougères, Philippe Soulier

We investigate conditions for the existence of the limiting conditional distribution of a bivariate random vector when one component becomes large. We revisit the existing literature on the topic, and present some new sufficient conditions. We concentrate on the case where the conditioning variable belongs to the maximum domain of attraction of the Gumbel la

Gergely Lukácsy, Péter Szeredi

This paper describes a resolution based Description Logic reasoning system called DLog. DLog transforms Description Logic axioms into a Prolog program and uses the standard Prolog execution for efficiently answering instance retrieval queries. From the Description Logic point of view, DLog is an ABox reasoning engine for the full SHIQ language. The DLog appr

Jicun Wang, Thomas Michelitsch, Arne Wunderlin, Ravi Mahadeva

It is now increasingly realized that the underlying mechanism which governs aging (ageing) is a complex interplay of genetic regulation and damage-accumulation. &#34;Aging as a result of accumulation of &#39;faults&#39; on cellular and molecular levels&#34;, has been proposed in the damage (fault)-accumulation theory. However, this theory fails to explain so

Evgeni Burovski, Giuliano Orso, Thierry Jolicoeur

We consider two-component one-dimensional quantum gases with density imbalance. While generically such fluids are two-component Luttinger liquids, we show that if the ratio of the densities is a rational number, p/q, and mass asymmetry between components is sufficiently strong, one of the two eigenmodes acquires a gap. The gapped phase corresponds to (algebr

J. E. Sprittles, Y. D. Shikhmurzaev

We show that an attempt to compute numerically a viscous flow in a domain with a piece-wise smooth boundary by straightforwardly applying well-tested numerical algorithms (and numerical codes based on their use, such as COMSOL Multiphysics) can lead to spurious multivaluedness and nonintegrable singularities in the distribution of the fluid&#39;s pressure. T

Francesco Cianfrani, Giovanni Montani, Simone Zonetti

The Brown-Kuchař mechanism is applied in the case of General Relativity coupled with the Schutz&#39; model for a perfect fluid. Using the canonical formalism and manipulating the set of modified constraints one is able to recover the definition of a time evolution operator, i.e. a physical Hamiltonian, expressed as a functional of gravitational variables and

Abhishek Agarwal, Donovan Young

We consider supersymmetric Wilson loops a la Zarembo in planar supersymmetric Yang-Mills theories in diverse dimensions. Using perturbation theory we show that these loops have trivial vacuum expectation values to second order in the &#39;t Hooft coupling. We review the known superspace results which, for specific dimensions, extend this triviality to all or

Mikhail Lemeshko, Bretislav Friedrich

By making use of the quantization rule of Raab and Friedrich [P. Raab and H. Friedrich, Phys. Rev. A 78, 022707 (2008)], we derive simple and accurate formulae for the number of rotational states supported by a weakly-bound vibrational level of a diatomic molecule and the rotational constants of any such levels up to the threshold, and provide a criterion fo

Laurent Manivel

We study the secant variety of the spinor variety, focusing on its equations of degree three and four. We show that in type $D_n$, cubic equations exist if and only if $n\ge 9$. In general the ideal has generators in degrees at least three and four. Finally we observe that the other Freudenthal varieties exhibit strikingly similar behaviors.

Sreraman Muralidharan, Sakshi Jain, Prasanta K. Panigrahi

We provide a number of schemes for the splitting up of quantum information among $k$ parties using a $N$-qubit linear cluster state as a quantum channel, such that the original information can be reconstructed only if all the parties cooperate. Explicit circuits are provided for these schemes, which are based on the concept of measurement based locking and u

Yunbao Huang

Carpi (1993) and Lepisto (1994) proved independently that smooth words are cube-free for the alphabet {1, 2}, but nothing is known on whether for the other 2-letter alphabets, smooth words are k-power-free for some suitable positive integer k. In this paper, we first establish the derivative formula of the concatenation of two smooth words and power derivati

E. J. Beggs, S. Majid

We develop the formalism for noncommutative differential geometry and Riemmannian geometry to take full account of the *-algebra structure on the (possibly noncommutative) coordinate ring and the bimodule structure on the differential forms. We show that *-compatible bimodule connections lead to braid operators $σ$ in some generality (going beyond the quantu

A. Patruno, A. L. Watts, M. Klein-Wolt, R. Wijnands

We present a simultaneous periodic and aperiodic timing study of the accreting millisecond X-ray pulsar SAX J1808.4-3658. We analyze five outbursts of the source and for the first time provide a full and systematic investigation of the enigmatic phenomenon of the 1 Hz flares observed during the final stages of some of the outbursts. We show that links betwee

Frank Ferrari, Vincent Wens

In this note, we solve an extended version of the N=1 super Yang-Mills theory with gauge group U(N), an adjoint chiral multiplet and Nf flavors of quarks, by using the N=1 microscopic formalism based on Nekrasov&#39;s sums over colored partitions. Our main new result is the computation of the general mesonic operators. We prove that the generalized Konishi a

Olivier Poujade, Mathieu Peybernes

For years, astrophysicists, plasma fusion and fluid physicists have puzzled over Rayleigh-Taylor turbulent mixing layers. In particular, strong discrepancies in the growth rates have been observed between experiments and numerical simulations. Although two phenomenological mechanisms (mode-coupling and mode-competition) have brought some insight on these dif

Martin Keller-Ressel, Antonis Papapantoleon, Josef Teichmann

We provide a general and flexible approach to LIBOR modeling based on the class of affine factor processes. Our approach respects the basic economic requirement that LIBOR rates are non-negative, and the basic requirement from mathematical finance that LIBOR rates are analytically tractable martingales with respect to their own forward measure. Additionally,

Tomohiro Takahashi, Jiro Soda

We study primordial gravitational waves produced during inflation in quantum gravity at a Lifshitz point proposed by Ho${\rm\check{r}}$ava. Assuming power-counting renormalizability, foliation preserving diffeomorphism invariance, and the condition of detailed balance, we show that primordial gravitational waves are circularly polarized due to parity violati

Manan Vyas, V. K. B. Kota

We introduce in this paper embedded Gaussian unitary ensemble of random matrices, for $m$ fermions in $Ω$ number of single particle orbits, generated by random two-body interactions that are SU(4) scalar, called EGUE(2)-SU(4). Here the SU(4) algebra corresponds to Wigner&#39;s supermultiplet SU(4) symmetry in nuclei. Formulation based on Wigner-Racah algebra

Hong-Hao Tu, Guang-Ming Zhang, Tao Xiang, Zheng-Xin Liu

We introduce a general method to construct one-dimensional translationally invariant valence bond solid states with a built-in Lie group $G$ and derive their matrix product representations. The general strategies to find their parent Hamiltonians are provided so that the valence bond solid states are their unique ground states. For quantum integer spin-$S$ c

Petar Kormushev, Kohei Nomoto, Fangyan Dong, Kaoru Hirota

This preprint has been withdrawn by the author for revision

Gentaro Watanabe, Hidetaka Sonoda, Toshiki Maruyama, Katsuhiko Sato

In supernova cores, nuclear &#34;pasta&#34; phases such as triangular lattice of rod-like nuclei and layered structure of slab-like nuclei are considered to exist. However, it is still unclear whether or not they are actually formed in collapsing supernova cores. Using {\it ab-initio} numerical simulations called the Quantum Molecular Dynamics (QMD), we here

Christian Duval, Péter A. Horvathy

This article provides us with a unifying classification of the conformal infinitesimal symmetries of non-relativistic Newton-Cartan spacetime. The Lie algebras of non-relativistic conformal transformations are introduced via the Galilei structure. They form a family of infinite-dimensional Lie algebras labeled by a rational &#34;dynamical exponent&#34;, $z$.

Markus Perling

In this article we survey recent results of joint work with Lutz Hille on exceptional sequences of invertible sheaves on rational surfaces and give examples.

Grzegorz Wilk, Zbigniew Wlodarczyk

The energy spectrum of cosmic rays (CR) exhibits power-like behavior with a very characteristic &#34;knee&#34; structure. We consider a possibility that such a spectrum could be generated by some specific nonstatistical temperature fluctuations in the source of CR with the &#34;knee&#34; structure reflecting an abrupt change of the pattern of such fluctuatio

Youn-Seok Choi, Ki-Suk Lee, Sang-Koog Kim

We studied magnetic vortex oscillations associated with vortex gyrotropic motion driven by spin-polarized out-of-plane dc current by analytical and micromagnetic numerical calculations. Reliable controls of the tunable eigenfrequency and orbital amplitude of persistent vortex oscillations were demonstrated. This work provides an advanced step towards the pra

Kyung Hoon Han

We show that noncommutative $L_p$-spaces satisfy the axioms of the (nonunital) operator system with a dominating constant $2^{1 \over p}$. Therefore, noncommutative $L_p$-spaces can be embedded into $B(H)$ $2^{1 \over p}$-completely isomorphically and complete order isomorphically.

Sayantani Bhattacharyya, Shiraz Minwalla

We use the AdS/CFT correspondence to study the thermalization of a strongly coupled conformal field theory that is forced out of its vacuum by a source that couples to a marginal operator. The source is taken to be of small amplitude and finite duration, but is otherwise an arbitrary function of time. When the field theory lives on $R^{d-1,1}$, the source se

J. R. Persson

The hyperfine anomalies in Gd and Nd have been extracted from the experimental hyperfine structure constants using a new method. In addition to the values of the hyperfine anomaly new improved values of the nuclear magnetic dipole moment ratios are derived.

Andriyan Bayu Suksmono

Direct inversion of incomplete visibility samples in VLBI (Very Large Baseline Interferometry) radio telescopes produces images with convolutive artifacts. Since proper analysis and interpretations of astronomical radio sources require a non-distorted image, and because filling all of sampling points in the uv-plane is an impossible task, image deconvolution

Paul E. Barclay, Kai-Mei Fu, Charles Santori, Raymond G. Beausoleil

A design for an ultra-high Q photonic crystal nanocavity engineered to interact with nitrogen-vacancy (NV) centers located near the surface of a single crystal diamond sample is presented. The structure is based upon a nanowire photonic crystal geometry, and consists of a patterned high refractive index membrane, such as gallium phosphide (GaP), supported by

David Hill, Jonathan Kujawa, Josh Sussan

We construct the finite dimensional simple integral modules for the (degenerate) affine Hecke-Clifford algebra (AHCA). Our construction includes an analogue of Zelevinsky&#39;s segment representations, a complete combinatorial description of the simple calibrated modules, and a classification of the simple integral modules. Additionally, we construct an anal

Donghui Jeong, Eiichiro Komatsu

We calculate the bispectrum, B_g(k_1,k_2,k_3), Fourier transform of the three-point function of density peaks (e.g., galaxies), using two different methods: the Matarrese-Lucchin-Bonometto formula and the locality of galaxy bias. The bispectrum of peaks is not only sensitive to that of the underlying matter density fluctuations, but also to the four-point fu

Guang-Ri Jin, Yong-Chun Liu, Wu-Ming Liu

We investigate the dependence of spin squeezing on the polar angle of the initial coherent spin state $|θ_0, ϕ_0>$ in a generalized one-axis twisting model, where the detuning $δ$ is taken into account. We show explicitly that regardless of $δ$ and $ϕ_0$, previous results of the ideal one-axis twisting is recovered as long as $θ_0=π/2$. For a small departure

A. L. Garcia-Perciante, L. S. Garcia-Colin, A. Sandoval-Villalbazo

In this paper we calculate the Rayleigh-Brillouin spectrum for a relativistic simple fluid according to three different versions available for a relativistic approach to non-equilibrium thermodynamics. An outcome of these calculations is that Eckart&#39;s version predicts that such spectrum does not exist. This provides an argument to question its validity.

J. -L. Le Gouet, P. R. Berman

We propose a scenario of quantum memory for light based on Raman scattering. The storage medium is a vapor and the different spectral components of the incoming signal are stored in different atomic velocity classes. One uses appropriate pulses to reverse the resulting Doppler phase shift and to regenerate the signal, without distortion, in the backward dire

W. Jozefowicz, L. Longa

We study the effect of fluctuations in opening angle of bent-core molecules on stability of the nematic phases. The molecules are built out of two Gay-Berne centers of $κ= 4$, $κ&#39; = 5$, $μ= 1$ and $ν= 2$, each corresponding to one of the molecular arms. Constant-pressure Monte Carlo (MC NPT) simulations are carried out for two versions of the model, with

Ryan Leaman, Andrew A. Cole, Kim A. Venn, Eline Tolstoy

We present the first determination of the radial velocities and metallicities of 78 red giant stars in the isolated dwarf irregular galaxy WLM. Observations of the calcium II triplet in these stars were made with FORS2 at the VLT-UT2 in two separated fields of view in WLM, and the [Fe/H] values were conformed to the Carretta & Gratton (1997) metallicity scal

Ahmad T. Ali, Mehmet Onder

In this paper, we define a rectifying spacelike curve in the Minkowski space-time $E_1^4$ as a curve whose position vector always lies in orthogonal complement $N^{\bot}$ of its principal normal vector field $N$. In particular, we study the rectifying spacelike curves in $E_1^4$ and characterize such curves in terms of their curvature functions.

Daniel Wegner, Gunter Kaindl

The structural and electronic properties of the surfaces of Sm(0001) and Eu/Gd(0001) were studied by scanning tunneling microscopy and spectroscopy at temperatures between 10 and 110 K. In both systems, an unoccupied surface state is observed that exhibits a temperature-dependent splitting into two states for Eu/Gd(0001), while it is unsplit on Sm(0001). Thi

J. C. Bustamante, D. Castonguay

We provide a counter-example to Proposition 3.2 of &#34;A note on the Fundamental Group of a Triangular Algebra&#34;, by F.Xu.

Boris Shapiro, Kouichi Takemura, Milos Tater

The well-known Heun equation has the form: Q(z)S&#39;&#39;(z)+P(z)S&#39;(z)+V(z)S(z)=0 where Q(z) is a cubic complex polynomial, P(z) and V(z) are polynomials of degrees at most 2 and 1 resp. One of the classical problems about the Heun equation is for a given positive integer N to find all possible linear polynomials V(z) such that the latter equation has a

Nisheeth Srivastava

We show that Boolean functions expressible as monotone disjunctive normal forms are PAC-evolvable under a uniform distribution on the Boolean cube if the hypothesis size is allowed to remain fixed. We further show that this result is insufficient to prove the PAC-learnability of monotone Boolean functions, thereby demonstrating a counter-example to a recent

Xi Chen, Decheng Dai, Ye Du, Shang-Hua Teng

We prove that the problem of computing an Arrow-Debreu market equilibrium is PPAD-complete even when all traders use additively separable, piecewise-linear and concave utility functions. In fact, our proof shows that this market-equilibrium problem does not have a fully polynomial-time approximation scheme unless every problem in PPAD is solvable in polynomi

David N. Levin

Given a time series of multicomponent measurements x(t), the usual objective of nonlinear blind source separation (BSS) is to find a &#34;source&#34; time series s(t), comprised of statistically independent combinations of the measured components. In this paper, the source time series is required to have a density function in (s,ds/dt)-space that is equal to

Bernd A. Berg

We document Fortran MPI checkerboard code for Markov Chain Monte Carlo simulations of pure SU(3) lattice gauge theory with the Wilson action on a D-dimensional double-layered torus. This includes the usual torus with periodic boundary conditions as an optional case. We use Cabibbo-Marinari heatbath checkerboard updating. Parallelization on sublattices is imp

Hyun Kyu Kim

In the first section of this senior thesis the author provides some new efficient algorithms for calculating with finite permutation groups. They cannot be found in the computer algebra system MAGMA, but they can be implemented there. For any finite group G with a given set of generators, the algorithms calculate generators of a fixed subgroup of G as short

Arlo U. Landolt

New broadband UBVRI photoelectric observations on the Johnson-Kron-Cousins photometric system have been made of 202 stars around the sky, and centered at the celestial equator. These stars constitute both an update of and additions to a previously published list of equatorial photometric standard stars. The list is capable of providing, for both celestial he

A. Pastorello, R. M. Crockett, R. Martin, S. J. Smartt

Type II-linear supernovae are thought to arise from progenitors that have lost most of their H envelope by the time of the explosion, and they are poorly understood because they are only occasionally discovered. It is possible that they are intrinsically rare, but selection effects due to their rapid luminosity evolution may also play an important role in li

Pierre Lescuyer, Mireille Chevallet, Sylvie Luche, Thierry Rabilloud

This unit describes strategies for studying the proteomes of organelles, which is one example of targeted proteomics. It relies heavily on previously published units dealing with organelle preparation, protein solubilization, and proteomics techniques. A specific commentary for organelle proteomics is provided. Specific protocols for the isolation of nuclei

J. Lazio, J. S. Bloom, G. C. Bower, J. Cordes

The time domain of the sky has been only sparsely explored. Nevertheless, recent discoveries from limited surveys and serendipitous discoveries indicate that there is much to be found on timescales from nanoseconds to years and at wavelengths from meters to millimeters. These observations have revealed unexpected phenomena such as rotating radio transients a

Susan M. Clark, Kai-Mei C. Fu, Qiang Zhang, Thaddeus D. Ladd

Spin-based quantum computing and magnetic resonance techniques rely on the ability to measure the coherence time, T2, of a spin system. We report on the experimental implementation of all-optical spin echo to determine the T2 time of a semiconductor electron-spin system. We use three ultrafast optical pulses to rotate spins an arbitrary angle and measure an

M. C. Werner

Recent work in gravitational lensing and catastrophe theory has shown that the sum of the signed magnifications of images near folds, cusps and also higher catastrophes is zero. Here, it is discussed how Lefschetz fixed point theory can be used to interpret this result geometrically. It is shown for the generic case as well as for elliptic and hyperbolic umb

Daniel P. Snowman

This paper considers a dilute Ising ferromangnet with annealed vacancies and attractive biquadratic interactions. Phase diagrams have been calculated while varying the temperature and concentration of annealed vacancies in the system while maintaining constant, attractive biquadratic couplings. These results have been produced using renormalization group ana

S. I. Maslovski

A theorem on subwavelength imaging with arrays of discrete sources is formulated. This theorem is analogous to the Kotelnikov (also named Nyquist-Shannon) sampling theorem as it represents the field at an arbitrary point of space in terms of the same field taken at discrete points and imposes similar limitations on the accuracy of the image. A physical reali

Rob Nendorf, Nick Scoville, Jeffrey Strom

We define and study the categorical sequence of a space, which is a new formalism that streamlines the computation of the Lusternik-Schnirelmann category of a space X by induction on its CW skeleta. The k-th term in the categorical sequence of a CW complex X, σ_X(k), is the least integer n for which cat_X(X_n) >= k. We show that σ_X is a well-defined homotop

C. Bourbonnais, D. Jerome

This review covers the study of some basic properties of the phase diagram of quasi-one-dimensional organic superconductors from both experimental and theoretical viewpoints.

E. Yu. Lerner

In this paper we answer certain questions posed by V.I. Arnold, namely, we study periods of continued fractions for solutions of quadratic equations in the form $x^2+p x=q$ with integer $p$ and $q$, $p^2+q^2\le R^2$. Our results concern the average sum of period elements and Gauss--Kuzmin statistics as $R\to\infty$.

M. P. Singh, K. D. Truong, P. Fournier, P. Rauwel

Double perovskites provide a unique opportunity to induce and control multiferroic behaviors in oxide systems. The appealing possibility to design materials with a strong coupling between the magnetization and the polarization fields may be achieved in this family since these magnetic insulators can present structural self-ordering in the appropriate growth

Robert J. Leamon, Scott W. McIntosh

We present a new method of visualizing the solar photospheric magnetic field based on the &#34;Magnetic Range of Influence&#34; (MRoI). The MRoI is a simple realization of the magnetic environment in the photosphere, reflecting the distance required to balance the integrated magnetic field contained in any magnetogram pixel. It provides a new perspective on

Geoffrey C. Clayton, D. Kilkenny, P. Wils, D. L. Welch

V532 Oph has been found to be a member of the rare, hydrogen-deficient R Coronae Borealis (RCB) stars from new photometric and spectroscopic data reported in this paper. The lightcurve of V532 Oph shows the sudden, deep, irregularly spaced declines characteristic of RCB stars. Its optical spectrum is typical of a warm (T(eff)~7000 K) RCB star, showing weak o

Claudio Dappiaggi, Thomas-Paul Hack, Nicola Pinamonti

We discuss from scratch the classical structure of Dirac spinors on an arbitrary globally hyperbolic, Lorentzian spacetime, their formulation as a locally covariant quantum field theory, and the associated notion of a Hadamard state. Eventually, we develop the notion of Wick polynomials for spinor fields, and we employ the latter to construct a covariantly c

Rebecca Johnston, A. N. Lasenby, M. P. Hobson

We investigate the dynamics of a cosmological dark matter fluid in the Schrödinger formulation, seeking to evaluate the approach as a potential tool for theorists. We find simple wave-mechanical solutions of the equations for the cosmological homogeneous background evolution of the dark matter field, and use them to obtain a piecewise analytic solution for t

Holger Gies, Joerg Jaeckel

We study a new kind of tunneling of particles through a barrier particular to quantum field theory. Here, the particles traverse the barrier by splitting into a virtual pair of particles of a different species which interacts only very weakly with the barrier and can therefore pass through it. Behind the barrier, the pair recombines into a particle of the or

D. L. Nika, S. Ghosh, E. P. Pokatilov, A. A. Balandin

The authors proposed a simple model for the lattice thermal conductivity of graphene in the framework of Klemens approximation. The Gruneisen parameters were introduced separately for the longitudinal and transverse phonon branches through averaging over phonon modes obtained from the first-principles. The calculations show that Umklapp-limited thermal condu

Nick E. Mavromatos

In this brief review I discuss ways and tests of CPT-Violation in the context of quantum gravity theories with space-time foam vacua, which entail quantum decoherence of matter propagating in such backgrounds. I cover a wide variety of sensitive probes, ranging from cosmic neutrinos to meson factories. I pay particular emphasis on associating the latter with

R. La Scala, V. Nardozza, D. Senato

We construct the analogue of the plactic monoid for the super semistandard Young tableaux over a signed alphabet. This is done by developing a generalization of the Knuth&#39;s relations. Moreover we get generalizations of Greene&#39;s invariants and Young-Pieri rule. A generalization of the symmetry theorem in the signed case is also obtained. Except for th

M. P. Singh, K. D. Truong, S. Jandl, P. Fournier

Ferromagnetic La3NiAlMnO9 (LNAMO) and La3CoAlMnO9 (LCAMO) triple-perovskite thin films are stabilized in the 750-860 oC temperature range in 100 to 900 mTorr O2 pressure range using pulsed-laser deposition. The LCAMO and LNAMO films exhibit ferromagnetism up to 190 K and 130 K respectively. The structural, optical and magnetic properties of these films demon

Sebastien Maret, Edwin A. Bergin, David A. Neufeld, Joel D. Green

We present mid-infrared spectral maps of the NGC 1333 star forming region, obtained with the the Infrared Spectrometer on board the Spitzer Space Telescope. Eight pure H2 rotational lines, from S (0) to S (7), are detected and mapped. The H2 emission appears to be associated with the warm gas shocked by the multiple outflows present in the region. A comparis

Wei Lu, Namrata Vaswani

We extend the Wiener-Khinchin theorem to non-wide sense stationary (WSS) random processes, i.e. we prove that, under certain assumptions, the power spectral density (PSD) of any random process is equal to the Fourier transform of the time-averaged autocorrelation function. We use the theorem to show that bandlimitedness of the PSD implies bandlimitedness of

R. Baranowski, R. Smolec, W. Dimitrov, T. Kwiatkowski

V440 Per is a Population I Cepheid with the period of 7.57 day and low amplitude, almost sinusoidal light and radial velocity curves. With no reliable data on the 1st harmonic, its pulsation mode identification remained controversial. We obtained a radial velocity curve of V440 Per with our new high precision and high throughput Poznan Spectroscopic Telescop