836 research outputs found
Nonlinear spectral calculus and super-expanders
Nonlinear spectral gaps with respect to uniformly convex normed spaces are
shown to satisfy a spectral calculus inequality that establishes their decay
along Cesaro averages. Nonlinear spectral gaps of graphs are also shown to
behave sub-multiplicatively under zigzag products. These results yield a
combinatorial construction of super-expanders, i.e., a sequence of 3-regular
graphs that does not admit a coarse embedding into any uniformly convex normed
space.Comment: Typos fixed based on referee comments. Some of the results of this
paper were announced in arXiv:0910.2041. The corresponding parts of
arXiv:0910.2041 are subsumed by the current pape
Asymptotically Extrinsic Tamed Submanifolds
We study, from the extrinsic point of view, the structure at infinity of open
submanifolds, ϕ : Mm → Mn(κ) isometrically immersed in the real space forms of
constant sectional curvature κ ≤ 0.We shall use the decay of the second fundamental
form of the so-called tamed immersions to obtain a description at infinity of the
submanifold in the line of the structural results in Greene et al. (Int Math Res Not
1994:364–377, 1994) and Petrunin and Tuschmann (Math Ann 321:775–788, 2001)
and an estimation from below of the number of its ends in terms of the volume growth
of a special class of extrinsic domains, the extrinsic balls.Vicent Gimeno: Work partially supported by the Research Program of University Jaume I Project UJI-B2016-07, and DGI -MINECO Grant (FEDER) MTM2013-48371-C2-2-P. Vicente Palmer: Work partially supported by the Research Program of University Jaume I Project UJI-B2016-07, DGI -MINECO Grant (FEDER) MTM2013-48371-C2-2-P, and Generalitat Valenciana Grant PrometeoII/2014/064. G. Pacelli Bessa: Work partially supported by CNPq- Brazil grant # 301581/2013-4
Macroscopic fluctuation theory
Stationary non-equilibrium states describe steady flows through macroscopic
systems. Although they represent the simplest generalization of equilibrium
states, they exhibit a variety of new phenomena. Within a statistical mechanics
approach, these states have been the subject of several theoretical
investigations, both analytic and numerical. The macroscopic fluctuation
theory, based on a formula for the probability of joint space-time fluctuations
of thermodynamic variables and currents, provides a unified macroscopic
treatment of such states for driven diffusive systems. We give a detailed
review of this theory including its main predictions and most relevant
applications.Comment: Review article. Revised extended versio
The community atmospheric chemistry box model CAABA/MECCA-4.0
We present version 4.0 of the atmospheric chemistry box
model CAABA/MECCA that now includes a number of new features: (i)
skeletal mechanism reduction, (ii) the Mainz Organic Mechanism (MOM) chemical mechanism for
volatile organic compounds, (iii) an option to include reactions from
the Master Chemical Mechanism (MCM) and other chemical mechanisms,
(iv) updated isotope tagging, and (v) improved and new photolysis
modules (JVAL, RADJIMT, DISSOC). Further, when MECCA is connected to a
global model, the new feature of coexisting multiple chemistry
mechanisms (PolyMECCA/CHEMGLUE) can be used. Additional changes have
been implemented to make the code more user-friendly and to facilitate
the analysis of the model results. Like earlier versions,
CAABA/MECCA-4.0 is a community model published under the
GNU General Public License.</p
Cosmology with Interaction between Phantom Dark Energy and Dark Matter and the Coincidence Problem
We study a cosmological model in which phantom dark energy is coupled to dark
matter by phenomenologically introducing a coupled term to the equations of
motion of dark energy and dark matter. This term is parameterized by a
dimensionless coupling function , Hubble parameter and the energy
density of dark matter, and it describes an energy flow between the dark energy
and dark matter. We discuss two cases: one is the case where the
equation-of-state of the dark energy is a constant; the other is
that the dimensionless coupling function is a constant. We investigate
the effect of the interaction on the evolution of the universe, the total
lifetime of the universe, and the ratio of the period when the universe is in
the coincidence state to its total lifetime. It turns out that the interaction
will produce significant deviation from the case without the interaction.Comment: Latex, 17 pages including 14 figures, minor change
On twisted Fourier analysis and convergence of Fourier series on discrete groups
We study norm convergence and summability of Fourier series in the setting of
reduced twisted group -algebras of discrete groups. For amenable groups,
F{\o}lner nets give the key to Fej\'er summation. We show that Abel-Poisson
summation holds for a large class of groups, including e.g. all Coxeter groups
and all Gromov hyperbolic groups. As a tool in our presentation, we introduce
notions of polynomial and subexponential H-growth for countable groups w.r.t.
proper scale functions, usually chosen as length functions. These coincide with
the classical notions of growth in the case of amenable groups.Comment: 35 pages; abridged, revised and update
Background field formalism and construction of effective action for N=2, d=3 supersymmetric gauge theories
We review the background field method for three-dimensional Yang-Mills and
Chern-Simons models in N=2 superspace. Superfield proper time (heat kernel)
techniques are developed and exact expressions of heat kernels for constant
backgrounds are presented. The background field method and heat kernel
techniques are applied for evaluating the low-energy effective actions in N=2
supersymmetric Yang-Mills and Chern-Simons models as well as in N=4 and N=8 SYM
theories.Comment: 1+30 pages, dedicated to the 60 year Jubilee of Professor D.I.
Kazakov; references added. arXiv admin note: substantial text overlap with
arXiv:1010.496
JUNO Conceptual Design Report
The Jiangmen Underground Neutrino Observatory (JUNO) is proposed to determine
the neutrino mass hierarchy using an underground liquid scintillator detector.
It is located 53 km away from both Yangjiang and Taishan Nuclear Power Plants
in Guangdong, China. The experimental hall, spanning more than 50 meters, is
under a granite mountain of over 700 m overburden. Within six years of running,
the detection of reactor antineutrinos can resolve the neutrino mass hierarchy
at a confidence level of 3-4, and determine neutrino oscillation
parameters , , and to
an accuracy of better than 1%. The JUNO detector can be also used to study
terrestrial and extra-terrestrial neutrinos and new physics beyond the Standard
Model. The central detector contains 20,000 tons liquid scintillator with an
acrylic sphere of 35 m in diameter. 17,000 508-mm diameter PMTs with high
quantum efficiency provide 75% optical coverage. The current choice of
the liquid scintillator is: linear alkyl benzene (LAB) as the solvent, plus PPO
as the scintillation fluor and a wavelength-shifter (Bis-MSB). The number of
detected photoelectrons per MeV is larger than 1,100 and the energy resolution
is expected to be 3% at 1 MeV. The calibration system is designed to deploy
multiple sources to cover the entire energy range of reactor antineutrinos, and
to achieve a full-volume position coverage inside the detector. The veto system
is used for muon detection, muon induced background study and reduction. It
consists of a Water Cherenkov detector and a Top Tracker system. The readout
system, the detector control system and the offline system insure efficient and
stable data acquisition and processing.Comment: 328 pages, 211 figure
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