343 research outputs found
Regolith production and transport at the Susquehanna Shale Hills Critical Zone Observatory, Part 2: Insights from meteoric 10Be
Regolith-mantled hillslopes are ubiquitous features of most temperate landscapes, and their morphology reflects the climatically, biologically, and tectonically mediated interplay between regolith production and downslope transport. Despite intensive research, few studies have quantified both of these mass fluxes in the same field site. Here we present an analysis of 87 meteoric 10Be measurements from regolith and bedrock within the Susquehanna Shale Hills Critical Zone Observatory (SSHO), in central Pennsylvania. Meteoric 10Be concentrations in bulk regolith samples (n=73) decrease with regolith depth. Comparison of hillslope meteoric 10Be inventories with analyses of rock chip samples (n=14) from a 24 m bedrock core confirms that >80% of the total inventory is retained in the regolith. The systematic downslope increase of meteoric 10Be inventories observed at SSHO is consistent with 10Be accumulation in slowly creeping regolith (∼ 0.2 cm yr-1). Regolith flux inferred from meteoric 10Be varies linearly with topographic gradient (determined from high-resolution light detection and ranging-based topography) along the upper portions of hillslopes at SSHO. However, regolith flux appears to depend on the product of gradient and regolith depth where regolith is thick, near the base of hillslopes. Meteoric 10Be inventories at the north and south ridgetops indicate minimum regolith residence times of 10.5 ± 3.7 and 9.1 ± 2.9 ky, respectively, similar to residence times inferred from U-series isotopes in Ma et al. (2013). The combination of our results with U-series-derived regolith production rates implies that regolith production and erosion rates are similar to within a factor of two on SSHO hillcrests. ©2013. American Geophysical Union. All Rights Reserved
Clebsch-Gordan and 6j-coefficients for rank two quantum groups
We calculate (q-deformed) Clebsch-Gordan and 6j-coefficients for rank two
quantum groups. We explain in detail how such calculations are done, which
should allow the reader to perform similar calculations in other cases.
Moreover, we tabulate the q-Clebsch-Gordan and 6j-coefficients explicitly, as
well as some other topological data associated with theories corresponding to
rank-two quantum groups. Finally, we collect some useful properties of the
fusion rules of particular conformal field theories.Comment: 43 pages. v2: minor changes and added references. For mathematica
notebooks containing the various q-CG and 6j symbols, see
http://arxiv.org/src/1004.5456/an
Dynamics and level statistics of interacting fermions in the lowest Landau level
We consider the unitary dynamics of interacting fermions in the lowest Landau level, on spherical and toroidal geometries. The dynamics are driven by the interaction Hamiltonian which, viewed in the basis of single-particle Landau orbitals, contains correlated pair hopping terms in addition to static repulsion. This setting and this type of Hamiltonian has a significant history in numerical studies of fractional quantum Hall (FQH) physics, but the many-body quantum dynamics generated by such correlated hopping has not been explored in detail. We focus on initial states containing all the fermions in one block of orbitals. We characterize in detail how the fermionic liquid spreads out starting from such a state. We identify and explain differences with regular (single-particle) hopping Hamiltonians. Such differences are seen, e.g. in the entanglement dynamics, in that some initial block states are frozen or near-frozen, and in density gradients persisting in long-time equilibrated states. Examining the level spacing statistics, we show that the most common Hamiltonians used in FQH physics are not integrable, and explain that GOE statistics (level statistics corresponding to the Gaussian orthogonal ensemble) can appear in many cases despite the lack of time-reversal symmetry
Successful transfer to sulfonylurea therapy in an infant with developmental delay, epilepsy and neonatal diabetes (DEND) syndrome and a novel ABCC8 gene mutation
Composite Fermion Wavefunctions Derived by Conformal Field Theory
The Jain theory of hierarchical Hall states is reconsidered in the light of
recent analyses that have found exact relations between projected Jain
wavefunctions and conformal field theory correlators. We show that the
underlying conformal theory is precisely given by the W-infinity minimal models
introduced earlier. This theory involves a reduction of the multicomponent
Abelian theory that is similar to the projection to the lowest Landau level in
the Jain approach. The projection yields quasihole excitations obeying
non-Abelian fractional statistics. The analysis closely parallels the bosonic
conformal theory description of the Pfaffian and Read-Rezayi states.Comment: 4 pages, 1 figur
Non-locality of non-Abelian anyons
Topological systems, such as fractional quantum Hall liquids, promise to
successfully combat environmental decoherence while performing quantum
computation. These highly correlated systems can support non-Abelian anyonic
quasiparticles that can encode exotic entangled states. To reveal the non-local
character of these encoded states we demonstrate the violation of suitable Bell
inequalities. We provide an explicit recipe for the preparation, manipulation
and measurement of the desired correlations for a large class of topological
models. This proposal gives an operational measure of non-locality for anyonic
states and it opens up the possibility to violate the Bell inequalities in
quantum Hall liquids or spin lattices.Comment: 7 pages, 3 figure
Quasiparticles and excitons for the Pfaffian quantum Hall state
We propose trial wave functions for quasiparticle and exciton excitations of
the Moore-Read Pfaffian fractional quantum Hall states, both for bosons and for
fermions, and study these numerically. Our construction of trial wave functions
employs a picture of the bosonic Moore-Read state as a symmetrized double layer
composite fermion state. We obtain the number of independent angular momentum
multiplets of quasiparticle and exciton trial states for systems of up to 20
electrons. We find that the counting for quasielectrons at large angular
momentum on the sphere matches that expected from the CFT which describes the
Moore-Read state's boundary theory. In particular, the counting for
quasielectrons is the same as for quasiholes, in accordance with the idea that
the CFT describing both sides of the FQH plateau should be the same. We also
show that our trial wave functions have good overlaps with exact wave functions
obtained using various interactions, including second Landau level Coulomb
interactions and the 3-body delta interaction for which the Pfaffian states and
their quasiholes are exact ground states. We discuss how these results relate
to recent work by Sreejith et al. on a similar set of trial wave functions for
excitations over the Pfaffian state as well as to earlier work by Hansson et
al., which has produced trial wave functions for quasiparticles based on
conformal field theory methods and by Bernevig and Haldane, which produced
trial wave functions based on clustering properties and `squeezing'.Comment: 22 pages, 18 figure
Paired and clustered quantum Hall states
We briefly summarize properties of quantum Hall states with a pairing or
clustering property. Their study employs a fundamental connection with
parafermionic Conformal Field Theories. We report on closed form expressions
for the many-body wave functions and on multiplicities of the fundamental
quasi-hole excitations.Comment: 13 pages, Contribution to the proceedings of the NATO Advanced
Research Workshop "Statistical Field Theories" Como (Italy), June 18-23 200
Mozambique’s policy framework for sustainable biofuels : A reflection on the development of the first African policy framework for sustainable biofuels
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