114,028 research outputs found
On the canonical divisor of smooth toroidal compactifications
In this paper, we show that the canonical divisor of a smooth toroidal
compactification of a complex hyperbolic manifold must be nef if the dimension
is greater or equal to three. Moreover, if we show that the numerical
dimension of the canonical divisor of a smooth -dimensional compactification
is always bigger or equal to . We also show that up to a finite \'etale
cover all such compactifications have ample canonical class, therefore refining
a classical theorem of Mumford and Tai. Finally, we improve in all dimensions
the cusp count for finite volume complex hyperbolic manifolds given
in [DD15a].Comment: Title shortened to match published versio
Gamma-Ray Astronomy around 100 TeV with a large Muon Detector operated at Very High Altitude
Measurements at 100 TeV and above are an important goal for the next
generation of high energy gamma-ray astronomy experiments to solve the still
open problem of the origin of galactic cosmic rays. The most natural
experimental solution to detect very low radiation fluxes is provided by the
Extensive Air Shower (EAS) arrays. They benefit from a close to 90% duty cycle
and a very large field of view (about 2 sr), but the sensitivity is limited by
their angular resolution and their poor cosmic ray background discrimination.
Above 10 TeV the standard technique for rejecting the hadronic background
consists in looking for "muon-poor" showers.
In this paper we discuss the capability of a large muon detector (A=2500 m2)
operated with an EAS array at very high altitude (>4000 m a.s.l.) to detect
gamma-ray fluxes around 100 TeV. Simulation-based estimates of energy ranges
and sensitivities are presented.Comment: 4 pages, proceedings of the 30th ICRC, Merida, Mexico, 200
nZVI particles production for the remediation of soil and water polluted by inorganic Lead
The present study deals with experiments of Pb removal by
nano-Zero Valent Iron (nZVI) in aqueous solution and in
soil. Synthetic Pb aqueous solutions were treated by nZVI,
at a fixed Pb concentration of 100 mg L-1
, varying
nanoparticles initial concentration in the range between 27
and 270 mg nZVI L-1
. A kinetic study was carried out: Pb
adsorption followed a first order kinetic, and half life times
between 11 and 26.66 min were determined. Soil samples
were first characterized, and Pb speciation and
concentration by sequential extractions was determined.
Adsorption tests were then carried out at three selected
amounts of nZVI, to allow Pb stabilization in the soil
matrix. To evaluate the treatment efficiency, sequential
extractions were also performed on the treated samples
Characterizing topological order by studying the ground states of an infinite cylinder
Given a microscopic lattice Hamiltonian for a topologically ordered phase, we
describe a tensor network approach to characterize its emergent anyon model
and, in a chiral phase, also its gapless edge theory. First, a tensor network
representation of a complete, orthonormal set of ground states on a cylinder of
infinite length and finite width is obtained through numerical optimization.
Each of these ground states is argued to have a different anyonic flux
threading through the cylinder. In a chiral phase, the entanglement spectrum of
each ground state is seen to reveal a different sector of the corresponding
gapless edge theory. A quasi-orthogonal basis on the torus is then produced by
chopping off and reconnecting the tensor network representation on the
cylinder. Elaborating on the recent proposal of [Y. Zhang et al. Phys. Rev. B
85, 235151 (2012)], a rotation on the torus yields an alternative basis of
ground states and, through the computation of overlaps between bases, the
modular matrices S and U (containing the mutual and self statistics of the
different anyon species) are extracted. As an application, we study the
hard-core boson Haldane model by using the two-dimensional density matrix
renormalization group. A thorough characterization of the universal properties
of this lattice model, both in the bulk and at the edge, unambiguously shows
that its ground space realizes the \nu=1/2 bosonic Laughlin state.Comment: 10 pages, 11 figure
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