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A Tight-Binding Investigation of the NaxCoO2 Fermi Surface
We perform an orthogonal basis tight binding fit to an LAPW calculation of
paramagnetic NaCoO for several dopings. The optimal position of the
apical oxygen at each doping is resolved, revealing a non-trivial dependence of
the band structure and Fermi surface on oxygen height. We find that the small
e hole pockets are preserved throughout all investigated dopings and
discuss some possible reasons for the lack of experimental evidence for these
Fermi sheets
Axial symmetry and conformal Killing vectors
Axisymmetric spacetimes with a conformal symmetry are studied and it is shown
that, if there is no further conformal symmetry, the axial Killing vector and
the conformal Killing vector must commute. As a direct consequence, in
conformally stationary and axisymmetric spacetimes, no restriction is made by
assuming that the axial symmetry and the conformal timelike symmetry commute.
Furthermore, we prove that in axisymmetric spacetimes with another symmetry
(such as stationary and axisymmetric or cylindrically symmetric spacetimes) and
a conformal symmetry, the commutator of the axial Killing vector with the two
others mush vanish or else the symmetry is larger than that originally
considered. The results are completely general and do not depend on Einstein's
equations or any particular matter content.Comment: 15 pages, Latex, no figure
Stress-free Spatial Anisotropy in Phase-Ordering
We find spatial anisotropy in the asymptotic correlations of two-dimensional
Ising models under non-equilibrium phase-ordering. Anisotropy is seen for
critical and off-critical quenches and both conserved and non-conserved
dynamics. We argue that spatial anisotropy is generic for scalar systems
(including Potts models) with an anisotropic surface tension. Correlation
functions will not be universal in these systems since anisotropy will depend
on, e.g., temperature, microscopic interactions and dynamics, disorder, and
frustration.Comment: 4 pages, 4 figures include
Putative fishery-induced changes in biomass and population size structures of demersal deep-sea fishes in ICES Sub-area VII, Northeast Atlantic Ocean
This work was supported by a series of NERC grants to the principal investigators including NE/C512961/1. The results of the early joint SAMS and IOS surveys were digitized with support from EU MAST Contract MAS2-CT920033 1993–1995, and data analyses was supported by EU FP7 Projects HERMES and HERMIONE. We thank Alain Zuur from Highland Statistics Ltd. for advice with the statistical analyses and Odd Aksel Bergstad for valuable comments that helped to improve the manuscript. We thank the ships’ companies of the RRS Challenger and RRS Discovery.Peer reviewedPublisher PD
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Ancient Cosmic Dust from Triassic Halite
We describe the discovery of fossil micrometeorites in ancient Triassic rock salt; the first to be found in salt and the oldest complete micrometeorites found to date. We present an estimated flux rate of micrometeorites to Earth at this time
Lax Operator for the Quantised Orthosymplectic Superalgebra U_q[osp(2|n)]
Each quantum superalgebra is a quasi-triangular Hopf superalgebra, so
contains a \textit{universal -matrix} in the tensor product algebra which
satisfies the Yang-Baxter equation. Applying the vector representation ,
which acts on the vector module , to one side of a universal -matrix
gives a Lax operator. In this paper a Lax operator is constructed for the
-type quantum superalgebras . This can in turn be used to
find a solution to the Yang-Baxter equation acting on
where is an arbitrary module. The case is included
here as an example.Comment: 15 page
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