722 research outputs found
Numerical investigation of gapped edge states in fractional quantum Hall-superconductor heterostructures
Fractional quantum Hall-superconductor heterostructures may provide a
platform towards non-abelian topological modes beyond Majoranas. However their
quantitative theoretical study remains extremely challenging. We propose and
implement a numerical setup for studying edge states of fractional quantum Hall
droplets with a superconducting instability. The fully gapped edges carry a
topological degree of freedom that can encode quantum information protected
against local perturbations. We simulate such a system numerically using exact
diagonalization by restricting the calculation to the quasihole-subspace of a
(time-reversal symmetric) bilayer fractional quantum Hall system of Laughlin
states. We show that the edge ground states are permuted by
spin-dependent flux insertion and demonstrate their fractional Josephson
effect, evidencing their topological nature and the Cooper pairing of
fractionalized quasiparticles.Comment: 12 pages, 9 figure
Carbon coating of the SPS dipole chambers
The Electron Multipacting (EM) phenomenon is a limiting factor for the
achievement of high luminosity in accelerators for positively charged particles
and for the performance of RF devices. At CERN, the Super Proton Synchrotron
(SPS) must be upgraded in order to feed the Large Hadron Collider (LHC) with 25
ns bunch spaced beams. At such small bunch spacing, EM may limit the
performance of the SPS and consequently that of the LHC. To mitigate this
phenomenon CERN is developing a carbon thin film coating with low Secondary
Electron Yield (SEY) to coat the internal walls of the SPS dipoles beam pipes.
This paper presents the progresses in the coating technology, the performance
of the carbon coatings and the strategy for a large scale production.Comment: 7 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop
on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba,
Italy; CERN Yellow Report CERN-2013-002, pp.141-14
Puromycin Sensitivity of Ribosomal Label after Incorporation of 14C-Labelled Amino Acids into Isolated Mitochondria from Neurospora crassa
Radioactive amino acids were incorporated into isolated mitochondria from Neurospora crassa. Then the mitochondrial ribosomes were isolated and submitted to density gradient centrifugation. A preferential labelling of polysomes was observed. However, when the mitochondrial suspension was treated with puromycin after amino acid incorporation, no radioactivity could be detected in either the monosomes or the polysomes. The conclusion is drawn that isolated mitochondria under these conditions do not incorporate significant amounts of amino acids into proteins of their ribosomes
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