1,479 research outputs found
AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors
This paper describes the proposed AIGO detector for the worldwide array of interferometric gravitational wave detectors. The first part of the paper summarizes the benefits that AIGO provides to the worldwide array of detectors. The second part gives a technical description of the detector, which will follow closely the Advanced LIGO design. Possible technical variations in the design are discussed
Evidence for an inflationary phase transition from the LSS and CMB anisotropy data
In the light of the recent Boomerang and Maxima observations of the CMB which
show an anomalously low second acoustic peak, we reexamine the prediction by
Adams et al (1997) that this would be the consequence of a 'step' in the
primordial spectrum induced by a spontaneous symmetry breaking phase transition
during primordial inflation. We demonstrate that a deviation from
scale-invariance around ~Mpc can simultaneously explain both
the feature identified earlier in the APM galaxy power spectrum as well the
recent CMB anisotropy data, with a baryon density consistent with the BBN
value. Such a break also allows a good fit to the data on cluster abundances
even for a critical density matter-dominated universe with zero cosmological
constant.Comment: 4 pages with 3 figures, LaTeX file using espcrc2.sty to appear on the
Proceedings of "Euroconference on Frontiers in Particle Astrophysics and
Cosmology",Sant Feliu de Guixols,Spain,30th September-5th October of 200
Suppression of electron scattering resonances in graphene by quantum dots
Transmission of low-energetic electrons through two-dimensional materials
leads to unique scattering resonances. These resonances contribute to
photoemission from occupied bands where they appear as strongly dispersive
features of suppressed photoelectron intensity. Using angle-resolved
photoemission we have systematically studied scattering resonances in epitaxial
graphene grown on the chemically differing substrates Ir(111), Bi/Ir, Ni(111)
as well as in graphene/Ir(111) nanopatterned with a superlattice of uniform Ir
quantum dots. While the strength of the chemical interaction with the substrate
has almost no effect on the dispersion of the scattering resonances, their
energy can be controlled by the magnitude of charge transfer from/to graphene.
At the same time, a superlattice of small quantum dots deposited on graphene
eliminates the resonances completely. We ascribe this effect to a
nanodot-induced buckling of graphene and its local rehybridization from
sp to sp towards a three-dimensional structure. Our results suggest
nanopatterning as a prospective tool for tuning optoelectronic properties of
two-dimensional materials with graphene-like structure.Comment: The following article has been submitted to Applied Physics Letters.
If it is published, it will be found online at http://apl.aip.or
Rashba splitting of 100 meV in Au-intercalated graphene on SiC
Intercalation of Au can produce giant Rashba-type spin-orbit splittings in
graphene but this has not yet been achieved on a semiconductor substrate. For
graphene/SiC(0001), Au intercalation yields two phases with different doping.
Here, we report the preparation of an almost pure p-type graphene phase after
Au intercalation. We observe a 100 meV Rashba-type spin-orbit splitting at 0.9
eV binding energy. We show that this giant splitting is due to hybridization
and much more limited in energy and momentum space than for Au-intercalated
graphene on Ni
Reconstruction of profinite groups from the closed normal hulls of its Sylow subgroups and natural actions
Digitization of the masters theses and Ph.D. dissertations of El Centro Interdisciplinario de Ciencias Marinas (CICMAR).
pp. 22
Deep-Sea Mining: a Manageable Necessity or a Curse?
The dependence of modern societies upon critical raw materials (nearly all metals) is overwhelming. Some believe that demand is growing faster than offer, not only because of geological availability but also for political
and economic reasons. For these reasons it is imperative to consider new sources for raw materials.The seafloor stands as a likely candidate. We must create readiness now to be prepared when the need comes. One of the greatest fears is the environmental cost involved in mining the deep seafloor. However, the mining industry no longer deserves its partially not favorable reputation. We need both the resources and the environment. And nIMBY (not In My Back Yard) will not help.info:eu-repo/semantics/publishedVersio
Observation of antiphase coherent phonons in the warped Dirac cone of Bi2Te3
In this Rapid Communication we investigate the coupling between excited electrons and phonons in the highly anisotropic electronic structure of the prototypical topological insulator Bi2Te3. Using time and angle resolved photoemission spectroscopy we are able to identify the emergence and ultrafast temporal evolution of the longitudinal optical A1g coherent phonon mode in Bi2Te3. We observe an antiphase behavior in the onset of the coherent phonon oscillations between the amp; 915;K and the amp; 915;M high symmetry directions that is consistent with warping. The qualitative agreement between our density functional theory calculations and the experimental results reveals the critical role of the anisotropic coupling between Dirac fermions and phonon modes in the topological insulator Bi2Te
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