1,572 research outputs found
IRAS 05358+3543: Multiple outflows at the earliest stages of massive star formation
We present a high-angular-resolution molecular line and millimeter continuum
study of the massive star formation site IRAS 05358+3543. The most remarkable
feature is a highly collimated (collimation factor ~10) and massive (>10 M_sun)
bipolar outflow of 1 pc length, which is part of a quadrupolar outflow system.
The three observed molecular outflows forming the IRAS 05358+3543 outflow
system resemble, in structure and collimation, those typical of low-mass
star-forming regions. They might therefore, just like low-mass outflows, be
explained by shock entrainment models of jets. We estimate a mass accretion
rate of 10^{-4) M_sun/yr, sufficient to overcome the radiative pressure of the
central object and to build up a massive star, lending further support to the
hypothesis that massive star formation occurs similarly to low-mass star
formation, only with higher accretion rates and energetics.Comment: 11 pages, 9 figures, accepted for Astronomy and Astrophysic
Finitary Group Cohomology and Group Actions on Spheres
We show that if G is an infinitely generated locally (polycyclic-by-finite)
group with cohomology almost everywhere finitary, then every finite subgroup of
G acts freely and orthogonally on some sphere.Comment: 6 page
Scaling Functions in the Odd Charge Sector of Sine-Gordon/Massive Thirring Theory
A non-linear integral equation (NLIE) governing the finite size effects of
excited states of even topological charge in the sine-Gordon (sG) / massive
Thirring (mTh) field theory, deducible from a light-cone lattice formulation of
the model, has been known for some time. In this letter we conjecture an
extension of this NLIE to states with odd topological charge, thus completing
the spectrum of the theory. The scaling functions obtained as solutions to our
conjectured NLIE are compared successfully with Truncated Conformal Space data
and the construction is shown to be compatible with all other facts known about
the local Hilbert spaces of sG and mTh models. With the present results we have
achieved a full control over the finite size behaviour of energy levels of
sG/mTh theory.Comment: LaTeX2e, 12 pp., 3 eps figs. Remarks on locality adde
Observation of Parity Nonconservation in Moller Scattering
We report a measurement of the parity-violating asymmetry in fixed target
electron-electron (Moller) scattering: A_PV = -175 +/- 30 (stat.) +/- 20
(syst.) parts per billion. This first direct observation of parity
nonconservation in Moller scattering leads to a measurement of the electron's
weak charge at low energy Q^e_W = -0.053 +/- 0.011. This is consistent with the
Standard Model expectation at the current level of precision:
sin^2\theta_W(M_Z)_MSbar = 0.2293 +/- 0.0024 (stat.) +/- 0.0016 (syst.) +/-
0.0006 (theory).Comment: Version 3 is the same as version 2. These versions contain minor text
changes from referee comments and a change in the extracted value of Q^e_W
and sin^2\theta_W due to a change in the theoretical calculation of the
bremsstrahulung correction (ref. 16
Are Genetically Robust Regulatory Networks Dynamically Different from Random Ones?
We study a genetic regulatory network model developed to demonstrate that
genetic robustness can evolve through stabilizing selection for optimal
phenotypes. We report preliminary results on whether such selection could
result in a reorganization of the state space of the system. For the chosen
parameters, the evolution moves the system slightly toward the more ordered
part of the phase diagram. We also find that strong memory effects cause the
Derrida annealed approximation to give erroneous predictions about the model's
phase diagram.Comment: To be published in Computer Simulation Studies in Condensed-Matter
Physics XX. Ed. by D.P. Landau, S. P. Lewis, H.-B. Schuttler
(Springer-Verlag, Berlin Heidelberg New York
Palynofacies classification of the depositional elements of confined turbidite systems : Examples from the Gres d'Annot, SE France
Acknowledgements We thank BG Brasil for financial support for this project and permission to publish. BG Group is a wholly owned subsidiary of Royal Dutch Shell. McArthur is grateful to the Coordenação de Aperfeiçoamento de Pessoal de NĂvel Superior (CAPES) for the scholarship 049/2012. The AgĂȘncia Nacional do PetrĂłleo (ANP) are thanked for supporting this project. Massimo Zecchin is thanked for handling this paper and Roberto Tinterri is thanked for his constructive review, in addition to an anonymous reviewer.Peer reviewedPostprin
Bogoliubov theory of quantum correlations in the time-dependent Bose-Hubbard model
By means of an adapted mean-field expansion for large fillings , we
study the evolution of quantum fluctuations in the time-dependent Bose-Hubbard
model, starting in the superfluid state and approaching the Mott phase by
decreasing the tunneling rate or increasing the interaction strength in time.
For experimentally relevant cases, we derive analytical results for the
temporal behavior of the number and phase fluctuations, respectively. This
allows us to calculate the growth of the quantum depletion and the decay of
off-diagonal long-range order. We estimate the conditions for the observability
of the time dependence in the correlation functions in the experimental setups
with external trapping present. Finally, we discuss the analogy to quantum
effects in the early universe during the inflationary epoch.Comment: 11 pages of RevTex4, 2 figures; significantly extended, with several
analytically solvable cases added, to appear in Physical Review
Rosenberg v. Levin, 7 Fla. L. W. 6 (1982)
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