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Sep 21, 2013
09/13
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F. J. Cao; M. Feito
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Feedback controlled ratchets are thermal rectifiers that use information on the state of the system to operate. We study the effects of time delays in the feedback for a protocol that performs an instantaneous maximization of the center-of-mass velocity in the many particle case. For small delays the center-of-mass velocity decreases for increasing delays (although not as fast as in the few particle case). However, for large delays we find the surprising result that the presence of a delay can...
Source: http://arxiv.org/abs/0706.4466v2
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Sep 19, 2013
09/13
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M. B. Wan; C. J. Olson Reichhardt; Z. Nussinov; C. Reichhardt
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We show that the recent experimental observation of the rectification of swimming bacteria in a system with an array of asymmetric barriers occurs due to the ballistic component of the bacteria trajectories introduced by the bacterial "motor." Each bacteria selects a random direction for motion and then moves in this direction for a fixed period of time before randomly changing its orientation and moving in a new direction. In the limit where the bacteria undergo only Brownian motion,...
Source: http://arxiv.org/abs/0708.3096v2
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Sep 23, 2013
09/13
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Florian Gmeiner; Chris D. White
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We demonstrate the possibility of examining cosmological signatures in the DBI inflation setup using the BGMPZ solution, a one-parameter family of geometries for the warped throat which interpolate between the Maldacena-Nunez and Klebanov-Strassler solutions. The warp factor is determined numerically and subsequently used to calculate cosmological observables including the scalar and tensor spectral indices, for a sample point in the parameter space. As one moves away from the KS solution for...
Source: http://arxiv.org/abs/0710.2009v3
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Sep 23, 2013
09/13
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I. Siddique; A. S. Kondratyev
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On the bases of the improved approximation for the spectral function of one-particle states the Landau-Silin kinetic equations for the normal Fermi liquids of neutral and electrically charged particles are shown to be valid at finite temperature above the temperature of superfluid transition.
Source: http://arxiv.org/abs/0710.0521v2
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Sep 23, 2013
09/13
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Hideki Asada
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We reexamined the gravitational time delay of light, allowing for various models of modified gravity. We clarify the dependence of the time delay (and induced frequency shift) on modified gravity models and investigate how to distinguish those models, when light propagates in static spherically symmetric spacetimes. Thus experiments by radio signal from spacecrafts at very different distances from Sun and future space-borne laser interferometric detectors could be a probe of modified gravity in...
Source: http://arxiv.org/abs/0710.0477v2
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Sep 23, 2013
09/13
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S. Fratini; H. Xie; I. N. Hulea; S. Ciuchi; A. F. Morpurgo
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Electronic transport through rubrene single-crystal field effect transistors (FETs) is investigated experimentally in the high carrier density regime (n ~ 0.1 carrier/molecule). In this regime, we find that the current does not increase linearly with the density of charge carriers, and tends to saturate. At the same time, the activation energy for transport unexpectedly increases with increasing n. We perform a theoretical analysis in terms of a well-defined microscopic model for interacting...
Source: http://arxiv.org/abs/0710.2845v2
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Sep 23, 2013
09/13
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Timothy A. Schroeder
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Associated to any Coxeter system $(W,S)$, there is a labeled simplicial complex $L$ and a contractible CW-complex $\Sigma_L$ (the Davis complex) on which $W$ acts properly and cocompactly. $\Sigma_L$ admits a cellulation under which the nerve of each vertex is $L$. It follows that if $L$ is a triangulation of $\mathbb{S}^{n-1}$, then $\Sigma_L$ is a contractible $n$-manifold. In this case, the orbit space, $K_L:=\Sigma_L/W$, is a \emph{Coxeter orbifold}. We prove a result analogous to the...
Source: http://arxiv.org/abs/0710.4358v2
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Sep 21, 2013
09/13
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Gianluca Calcagni; Michele Montobbio; Giuseppe Nardelli
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We show that a certain class of nonlocal scalar models, with a kinetic operator inspired by string field theory, is equivalent to a system which is local in the coordinates but nonlocal in an auxiliary evolution variable. This system admits both Lagrangian and Hamiltonian formulations, and its Cauchy problem and quantization are well-defined. We classify exact nonperturbative solutions of the localized model which can be found via the diffusion equation governing the fields.
Source: http://arxiv.org/abs/0712.2237v2
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Sep 21, 2013
09/13
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Ling-Yan Hung; Linda I. Uruchurtu
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The near horizon geometry of a fundamental string wrapped around an S1 reduced to four dimensions is expected to be AdS2 x S2. A probe string analysis suggests a no-force condition indicating supersymmetry, which coincides with the condition that the AdS2 is embedded in AdS3. We therefore consider the bulk string theory in terms of a WZW model on AdS3 following recent proposals by Dabholkar et. al and Giveon et. al. We find that conformal symmetry of the model naturally leads to the no-force...
Source: http://arxiv.org/abs/0712.2860v2
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Sep 23, 2013
09/13
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Albert Zijlstra; P. A. M. van Hoof; R. A. Perley
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We present the results of a 25-year program to monitor the radio flux evolution of the planetary nebula NGC7027. We find significant evolution of the spectral flux densities. The flux density at 1465 MHz, where the nebula is optically thick, is increasing at a rate of 0.251+-0.015 % per year, caused by the expansion of the ionized nebula. At frequencies where the emission is optically thin, the spectral flux density is changing at a rate of -0.145+-0.005 % per year, caused by a decrease in the...
Source: http://arxiv.org/abs/0801.3327v1
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Sep 22, 2013
09/13
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Konstantin V. Khishchenko; Mikhail E. Veysman; Nikolay E. Andreev; Vladimir E. Fortov; Pavel R. Levashov; Mikhail E. Povarnitsyn
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A theoretical model is developed for the interaction of intense femtosecond laser pulses with solid targets on the basis of the two-temperature equation of state for an irradiated substance. It allows the description of the dynamics of the plasma formation and expansion. Comparison of available experimental data on the amplitude and phase of the complex reflection coefficient of aluminum with the simulation results provides new information on the transport coefficients and absorption capacity...
Source: http://arxiv.org/abs/0805.0408v1
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Sep 22, 2013
09/13
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Benjamin Fuks
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We present precision calculations of the transverse-momentum spectrum, the invariant-mass distribution and the total cross section for Z' production at hadron colliders. We implement joint resummation at the next-to-leading logarithmic accuracy and consistently match the obtained result with the pure perturbative result at the first order in the strong coupling constant. We confront our numerical predictions with the Monte Carlo generator PYTHIA and with a new implementation of extra neutral...
Source: http://arxiv.org/abs/0805.2004v2
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Sep 22, 2013
09/13
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W. Gieren; G. Pietrzynski; O. Szewczyk; F. Bresolin; R. -P. Kudritzki; M. A. Urbaneja; J. Storm; D. Minniti
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We have obtained deep images in the near-infrared J and K filters for several fields in the Local Group galaxy WLM. We report intensity mean magnitudes for 31 Cepheids located in these fields which we previously discovered in a wide-field optical imaging survey of WLM. The data define tight period-luminosity relations in both near-infrared bands which we use to derive the total reddening of the Cepheids in WLM and the true distance modulus of the galaxy from a multiwavelength analysis of the...
Source: http://arxiv.org/abs/0805.2655v1
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Sep 22, 2013
09/13
by
Amanda Weltman
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We review some recent developments in chameleon models. In particular we discuss the possibility of chameleons coupling both to photons and baryonic matter with different coupling strengths. We will discuss the possibility of probing the chameleon-photon coupling with quantum vacuum experiments in the laboratory.
Source: http://arxiv.org/abs/0805.3461v1
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Sep 22, 2013
09/13
by
Ken-ichiro Arita; Matthias Brack
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We discuss various bifurcation problems in which two isolated periodic orbits exchange periodic ``bridge'' orbit(s) between two successive bifurcations. We propose normal forms which locally describe the corresponding fixed point scenarios on the Poincar\'e surface of section. Uniform approximations for the density of states for an integrable Hamiltonian system with two degrees of freedom are derived and successfully reproduce the numerical quantum-mechanical results.
Source: http://arxiv.org/abs/0805.3755v3
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Sep 22, 2013
09/13
by
Yoshihiro Nambu
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We present a new and feasible test proving quantum contextuality in four-dimensional Hiltbert space. In our scheme, a contradiction between quantum mechanics and noncontextual hidden variables is revealed through the measurement statistics of two joint measurements of an ensemble of non-entangled qubits. The origin of nonclassicality is fully attributed to the measurement process. Quantum optical realization using photon pairs and linear optics are presented.
Source: http://arxiv.org/abs/0805.3398v3
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Sep 22, 2013
09/13
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Barbara Ercolano; Jeremy J. Drake; John C. Raymond; Cathie C. Clarke
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We present MOCASSIN 2D photoionisation and dust radiative transfer models of a prototypical T Tauri disk irradiated by X-rays from the young pre-main sequence star. The calculations demonstrate a layer of hot gas reaching temperatures of ~10^6 K at small radii and ~10^4 K at a distance of 1 AU. The gas temperatures decrease sharply with depth, but appear to be completely decoupled from dust temperatures down to a column depth of ~5*10^21 cm^-2. We predict that several fine-structure and...
Source: http://arxiv.org/abs/0805.4625v1
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Sep 18, 2013
09/13
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Xiaowen Jia; Haiyun Liu; Wentao Zhang; Lin Zhao; Jianqiao Meng; Guodong Liu; Xiaoli Dong; G. F. Chen; J. L. Luo; N. L. Wang; Z. A. Ren; Wei Yi; Jie Yang; Wei Lu; G. C. Che; G. Wu; R. H. Liu; X. H. Chen; Guiling Wang; Yong Zhou; Yong Zhu; Xiaoyang Wang; Zhongxian Zhao; Zuyan Xu; Chuangtian Chen; X. J. Zhou
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High resolution photoemission measurements have been carried out on non-superconducting LaOFeAs parent compound and various superconducting R(O1-xFx)FeAs (R=La, Ce and Pr) compounds. We found that the parent LaOFeAs compound shows a metallic character. Through extensive measurements, we have identified several common features in the electronic structure of these Fe-based compounds: (1). 0.2 eV feature in the valence band; (2). A universal 13~16 meV feature; (3). A clear Fermi cutoff showing...
Source: http://arxiv.org/abs/0806.0291v2
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Sep 18, 2013
09/13
by
Zhenting Hou; Li Tan; Dinghua Shi
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eye 39
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In this paper, first-passage probability of Markov chains is used to get a strict proof of the existence of degree distribution of the LCD model presented by Bollobas (Random Structures and Algorithms 18(2001)). Also, a precise expression of degree distribution is presented.
Source: http://arxiv.org/abs/0806.0448v1
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Sep 18, 2013
09/13
by
Yvonne Y. Y. Wong
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We present the first systematic derivation of the one-loop correction to the large scale matter power spectrum in a mixed cold+hot dark matter cosmology with subdominant massive neutrino hot dark matter. Starting with the equations of motion for the density and velocity fields, we derive perturbative solutions to these quantities and construct recursion relations for the interaction kernels, noting and justifying all approximations along the way. We find interaction kernels similar to those for...
Source: http://arxiv.org/abs/0809.0693v2
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Sep 18, 2013
09/13
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C. Carrasco-Gonzalez; G. Anglada; L. F. Rodriguez; J. M. Torrelles; M. Osorio
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Star forming regions are expected to show linear proper motions due to the relative motion of the Sun with respect to the region. These proper motions appear superposed to the proper motions expected in features associated with mass ejection from the young stellar objects embedded in them. Therefore, it is necessary to have a good knowledge of the proper motions of the region as a whole in order to correctly interpret the motions associated with mass ejection. In this paper we present the first...
Source: http://arxiv.org/abs/0809.0315v1
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Sep 18, 2013
09/13
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P. C. Rout; D. R. Chakrabarty; V. M. Datar; Suresh Kumar; E. T. Mirgule; A. Mitra; V. Nanal; R. Kujur
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A large area plastic scintillator detector array(~ 1 m x1m) has been set up for fast neutron spectroscopy at the BARC-TIFR Pelletron laboratory, Mumbai. The energy, time and position response has been measured for electrons using radioactive sources and for mono-energetic neutrons using the 7Li(p,n1)7Be*(0.429 MeV) reaction at proton energies between 6.3 and 19 MeV. A Monte Carlo simulation of the energy dependent efficiency of the array for neutron detection is in agreement with the 7Li(p,n1)...
Source: http://arxiv.org/abs/0809.0794v1
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Sep 18, 2013
09/13
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M. Capone; M. Fabrizio; C. Castellani; E. Tosatti
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The trivalent alkali fullerides A$_3$C$_{60}$, where C$_{60}$ are a well established family of molecular superconductors. The electron pairing has s-wave symmetry and is due to standard electron-phonon coupling, in particular by Jahn-Teller intramolecular C$_{60}$ vibrations. A source of renewed interest in these systems are indications of strong electron-electron repulsion, which emerges especially in compounds where the C$_{60}$-C$_{60}$ distance is expanded. In several compounds after an...
Source: http://arxiv.org/abs/0809.0910v1
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Sep 18, 2013
09/13
by
Monika Dorfler; Bruno Torresani
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Starting from a general operator representation in the time-frequency domain, this paper addresses the problem of approximating linear operators by operators that are diagonal or band-diagonal with respect to Gabor frames. A characterization of operators that can be realized as Gabor multipliers is given and necessary conditions for the existence of (Hilbert-Schmidt) optimal Gabor multiplier approximations are discussed and an efficient method for the calculation of an operator's best...
Source: http://arxiv.org/abs/0809.2698v1
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Sep 18, 2013
09/13
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K. P. Reardon; F. Lepreti; V. Carbone; A. Vecchio
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We study the acoustic properties of the solar chromosphere in the high-frequency regime using a time sequence of velocity measurements in the chromospheric Ca II 854.2 nm line taken with the Interferometric Bidimensional Spectrometer (IBIS). We concentrate on quiet-Sun behavior, apply Fourier analysis, and characterize the observations in terms of the probability density functions (PDFs) of velocity increments. We confirm the presence of significant oscillatory fluctuation power above the...
Source: http://arxiv.org/abs/0809.4243v1
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Sep 23, 2013
09/13
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Jie Sun; Erik M. Bollt; Takashi Nishikawa
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We derive variational equations to analyze the stability of synchronization for coupled near-identical oscillators. To study the effect of parameter mismatch on the stability in a general fashion, we define master stability equations and associated master stability functions, which are independent of the network structure. In particular, we present several examples of coupled near-identical Lorenz systems configured in small networks (a ring graph and sequence networks) with a fixed parameter...
Source: http://arxiv.org/abs/0810.2775v1
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Sep 22, 2013
09/13
by
Heng Lian
texts
eye 24
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This article investigates nonparametric estimation of variance functions for functional data when the mean function is unknown. We obtain asymptotic results for the kernel estimator based on squared residuals. Similar to the finite dimensional case, our asymptotic result shows the smoothness of the unknown mean function has an effect on the rate of convergence. Our simulaton studies demonstrate that estimator based on residuals performs much better than that based on conditional second moment...
Source: http://arxiv.org/abs/0812.2628v1
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Sep 22, 2013
09/13
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T. Dahm; V. Hinkov; S. V. Borisenko; A. A. Kordyuk; V. B. Zabolotnyy; J. Fink; B. Büchner; D. J. Scalapino; W. Hanke; B. Keimer
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Theories based on the coupling between spin fluctuations and fermionic quasiparticles are among the leading contenders to explain the origin of high-temperature superconductivity, but estimates of the strength of this interaction differ widely. Here we analyze the charge- and spin-excitation spectra determined by angle-resolved photoemission and inelastic neutron scattering, respectively, on the same crystals of the high-temperature superconductor YBa2Cu3O6.6. We show that a self-consistent...
Source: http://arxiv.org/abs/0812.3860v1
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Sep 22, 2013
09/13
by
Clifton Cunningham; Hadi Salmasian
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This paper concerns character sheaves of connected reductive algebraic groups defined over non-Archimedean local fields and their relation with characters of smooth representations. Although character sheaves were devised with characters of representations of finite groups of Lie type in mind, character sheaves are perfectly well defined for reductive algebraic groups over any algebraically closed field. Nevertheless, the relation between character sheaves of an algebraic group $G$ over an...
Source: http://arxiv.org/abs/0812.4636v1
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Sep 21, 2013
09/13
by
C. Zhang; G. -C. Liu
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eye 40
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Based on minimal supersymmetric standard model, neutralino dark matter annihilation induced gamma ray emission from galaxy cluster 1E0657-56 is calculated. The merge of bullet-like subcluster with the main cluster is also investigated.
Source: http://arxiv.org/abs/0901.0059v1
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3.0
Aug 28, 2015
08/15
by
Ellis, Richard, 1938-
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Includes bibliographical references (p. [293]-319) and index
Topics: Bluefin tuna, Bluefin tuna fisheries, Endangered species
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0.0
Feb 23, 2014
02/14
by
CNN Money
movies
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The big banks declare earnings this week, which will help spotlight just how much they may be hurting.
Topic: CNN Money Archive
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Sep 23, 2013
09/13
by
Oswin Aichholzer; Jesús García; David Orden; Pedro Ramos
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In this paper we present three different results dealing with the number of $(\leq k)$-facets of a set of points: 1. We give structural properties of sets in the plane that achieve the optimal lower bound $3\binom{k+2}{2}$ of $(\leq k)$-edges for a fixed $0\leq k\leq \lfloor n/3 \rfloor -1$; 2. We give a simple construction showing that the lower bound $3\binom{k+2}{2}+3\binom{k-\lfloor \frac{n}{3} \rfloor+2}{2}$ for the number of $(\leq k)$-edges of a planar point set appeared in [Aichholzer...
Source: http://arxiv.org/abs/0801.1036v2
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Sep 23, 2013
09/13
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G. Michaud; J. Richer
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A brief review of various methods to calculate radiative accelerations for stellar evolution and an analysis of their limitations are followed by applications to Pop I and Pop II stars. Recent applications to Horizontal Branch (HB) star evolution are also described. It is shown that models including atomic diffusion satisfy Schwarzschild's criterion on the interior side of the core boundary on the HB without the introduction of overshooting. Using stellar evolution models starting on the Main...
Source: http://arxiv.org/abs/0801.4055v1
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Sep 23, 2013
09/13
by
Vladimir Gol'dshtein; Marc Troyanov
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We give sufficient conditions for the naturallity of the exterior differential under Sobolev mappings. In other words we study the validity of the equation $d f^* \alpha = f^* d\alpha$ for a smooth form $\alpha$ and a Sobolev map $f$.
Source: http://arxiv.org/abs/0801.4295v1
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Sep 20, 2013
09/13
by
Giuseppe Metere
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Higher Dimensional Categories are showing relevant implications in several fields of mathematical research. Nevertheless basic algebraic tools, in order to further develop the theory, are far from being established. In this thesis we introduce a notion of exactness for exact sequences of pointed n-groupoids. Furthermore we test it generalizing a well known result for (fibrations of) groupoids [R.Brown, 1970]. Namely, given a fibration F of (pointed) groupoids and its strict kernel it is...
Source: http://arxiv.org/abs/0802.0800v1
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Sep 20, 2013
09/13
by
Man-On Pun; Kyeong Jin Kim; H. Vincent Poor
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Opportunistic scheduling and beamforming schemes with reduced feedback are proposed for MIMO-OFDMA downlink systems. Unlike the conventional beamforming schemes in which beamforming is implemented solely by the base station (BS) in a per-subcarrier fashion, the proposed schemes take advantages of a novel channel decomposition technique to perform beamforming jointly by the BS and the mobile terminal (MT). The resulting beamforming schemes allow the BS to employ only {\em one} beamforming matrix...
Source: http://arxiv.org/abs/0802.4291v1
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Sep 18, 2013
09/13
by
SVD Collaboration
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The inclusive reaction $p A \to pK^0_s + X$ was studied at IHEP accelerator with $70 GeV/c$ proton beam using SVD-2 detector. Two different samples of $K^0_s$, statistically independent and belonging to different phase space regions, were used in the analyses and a narrow baryon resonance with the mass $M=1523\pm 2(stat.)\pm 3(syst.) MeV/c^2$ was observed in both samples of the data. The combined statistical significance was estimated to be of 8.0 (392 signal over 1990 background events). Using...
Source: http://arxiv.org/abs/0803.3313v2
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Sep 18, 2013
09/13
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Michael C. Abbott; Inês Aniceto
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The single spike is a rigidly rotating classical string configuration closely related to the giant magnon. We calculate bosonic and fermionic modes of this solution, from which we see that it is not supersymmetric. It can be viewed as an excitation above a hoop of string wound around the equator, in the same sense that the magnon is an excitation above an orbiting point particle. We find the operator which plays the role of the Hamiltonian for this sector, which compared to the magnon's E-J has...
Source: http://arxiv.org/abs/0803.4222v2
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Sep 18, 2013
09/13
by
S Rombetto; A Vettoliere; C Granata; M Russo; C Nappi
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We calculate the flux threading the pick-up coil of a square SQUID magnetometer in the presence of a current dipole source. The result reproduces that of a circle coil magnetometer calculated by Wikswo with only small differences. However it has a simpler form so that it is possible to derive from it closed form expressions for the current dipole sensitivity and the spatial resolution. The results are useful to assess the overall performance of the device and to compare different designs.
Source: http://arxiv.org/abs/0803.4425v1
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Jul 20, 2013
07/13
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Rodolfo Casana; Manoel M. Ferreira Jr; Carlos E. H. Santos
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In the present work, we investigate classical solutions of the Maxwell-Carroll-Field-Jackiw-Proca (MCFJP) electrodynamics for the cases a purely timelike and spacelike Lorentz-violating (LV) background. Starting from the MCFJP Lagrangian and the associated wave equations written for the potential four-vector, the tensor form of the Green function is achieved. In the timelike case, the components of the stationary Green function are explicitly written. The classical solutions for the electric...
Source: http://arxiv.org/abs/0804.0431v2
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Jul 20, 2013
07/13
by
M. Bertola; S. Y. Lee
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We describe the spectral statistics of the first finite number of eigenvalues in a newly-forming band on the hard-edge of the spectrum of a random Hermitean matrix model. It is found that in a suitable scaling regime, they are described by the same spectral statistics of a finite-size Laguerre-type matrix model. The method is rigorously based on the Riemann-Hilbert analysis of the corresponding orthogonal polynomials.
Source: http://arxiv.org/abs/0804.1111v1
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Jul 20, 2013
07/13
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W. Zhu; M. L. Liang; Q. W. Shi; Z. F. Wang; J. Chen; J. G. Hou
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In this paper, we numerically study the bound electron states induced by long range Coulomb impurity in gapped graphene and the quasi-bound states in supercritical region based on the lattice model. We present a detailed comparison between our numerical simulations and the prediction of the continuum model which is described by the Dirac equation in (2+1)-dimensional Quantum Electrodynamics (QED). We also use the Fano's formalism to investigate the quasi-bound state development and design an...
Source: http://arxiv.org/abs/0804.0984v1
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Jul 20, 2013
07/13
by
H. M. Fried; T. Grandou; Y. -M. Sheu
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In anticipation of a subsequent application to QCD, we consider the case of QED at high temperature. We introduce a Fradkin representation into the exact, Schwingerian, functional expression of a fermion propagator, as well as a new and relevant version of the Bloch-Nordsieck (BN) model, which extracts the soft contributions of every perturbative graph, in contradistinction to the assumed separation of energy scales of previous semi-perturbative treatments. Our results are applicable to the...
Source: http://arxiv.org/abs/0804.1591v1
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Jul 20, 2013
07/13
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Nicholas A. Licata; Alexei V. Tkachenko
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In recent years there have been a number of proposals to utilize the specificity of DNA based interactions for potential applications in nanoscience. One interesting direction is the self-assembly of micro- and nanoparticle clusters using DNA scaffolds. In this letter we consider a DNA scaffold method to self-assemble clusters of "colored" particles. Stable clusters of microspheres have recently been produced by an entirely different method. Our DNA based approach self-assembles...
Source: http://arxiv.org/abs/0804.3807v2
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Jul 20, 2013
07/13
by
A. S. Barabash; Ph. Hubert; A. Nachab; S. I. Konovalov; I. A. Vanyushin; V. I. Umatov
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Limits on $\beta^+$EC and ECEC processes in $^{112}$Sn and on $\beta^-\beta^-$ decay of $^{124}$Sn to the excited states of $^{124}$Te have been obtained using a 380 cm$^3$ HPGe detector and an external source consisting of natural tin. A limit with 90% C.L. on the $^{112}$Sn half-life of $0.92\times 10^{20}$ y for the ECEC(0$\nu$) transition to the $0^+_3$ excited state in $^{112}$Cd (1871.0 keV) has been established. This transition is discussed in the context of a possible enhancement of the...
Source: http://arxiv.org/abs/0804.3849v2
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Jul 20, 2013
07/13
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Andrew J. Walsh; Nadia Lo; Michael G. Burton; Graeme L. White; Cormac R. Purcell; Steven N. Longmore; Chris J. Phillips; Kate J. Brooks
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We describe observations with the Mopra radiotelescope designed to assess the feasibility of the H$_2$O maser southern Galactic plane survey (HOPS). We mapped two one-square-degree regions along the Galactic plane using the new 12 mm receiver and the UNSW Mopra spectrometer (MOPS). We covered the entire spectrum between 19.5 and 27.5 GHz using this setup with the main aims of finding out which spectral lines can be detected with a quick mapping survey. We report on detected emission from H$_2$O...
Source: http://arxiv.org/abs/0804.4035v1
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Jul 20, 2013
07/13
by
A. V. Timofeev; C. Pascual Garcia; N. B. Kopnin; A. M. Savin; M. Meschke; F. Giazotto; J. P. Pekola
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We study quasiparticle energy relaxation at sub-kelvin temperatures by injecting hot electrons into an aluminium island and measuring the energy flux from electrons into phonons both in the superconducting and in the normal state. The data show strong reduction of the flux at low temperatures in the superconducting state, in qualitative agreement with the presented quasiclassical theory for clean superconductors. Quantitatively, the energy flux exceeds that from the theory both in the...
Source: http://arxiv.org/abs/0804.4413v1
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Jul 20, 2013
07/13
by
Hilmar Böhm; Rainer von Sachs
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In this paper we investigate the performance of periodogram based estimators of the spectral density matrix of possibly high-dimensional time series. We suggest and study shrinkage as a remedy against numerical instabilities due to deteriorating condition numbers of (kernel) smoothed periodogram matrices. Moreover, shrinking the empirical eigenvalues in the frequency domain towards one another also improves at the same time the Mean Squared Error (MSE) of these widely used nonparametric...
Source: http://arxiv.org/abs/0804.4738v2
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Sep 22, 2013
09/13
by
Hiroaki Kohyama
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We construct the phase diagram of the chiral and diquark condensates at finite temperature and density in the 1+1 dimensional (2D) two flavor massless Gross Neveu model. The resultant phase diagram shows (I) the chiral condensed phase at low temperature and density, (II) the diquark condensed phase at low temperature and high density, and (III) the chiral and diquark coexisting phase at low temperature and intermediate density. This phase structure is also seen in the 3D Gross Neveu model and...
Source: http://arxiv.org/abs/0805.0003v1
