121,753 research outputs found
On the Lattice of p-Consequences
This paper is devoted to investigation of the lattice properties of p-consequences. Our main goal is to compare the algebraic features of the lattices composed of all p-consequences and all consequence operations defined on the same propositional language
Magnetism of Cold Fermionic Atoms on p-Band of an Optical Lattice
We carry out \textit{ab initio} study of ground state phase diagram of
spin-1/2 cold fermionic atoms within two-fold degenerate -band of an
anisotropic optical lattice. Using the Gutzwiller variational approach, we show
that a robust ferromagnetic phase exists for a vast range of band fillings and
interacting strengths. The ground state crosses over from spin density wave
state to spin-1 Neel state at half filling. Additional harmonic trap will
induce spatial separation of varies phases. We also discuss several relevant
observable consequences and detection methods. Experimental test of the results
reported here may shed some light on the long-standing issue of itinerant
ferromagnetism.Comment: 5 pages, 4 figure
Antiferromagnetism of ZnVO(PO and the dilution with Ti
We report static and dynamic properties of the antiferromagnetic compound
Zn(VO)(PO), and the consequences of non-magnetic Ti
doping at the V site. P nuclear magnetic resonance (NMR) spectra
and spin-lattice relaxation rate () consistently show the formation of
the long-range antiferromagnetic order below \,K. The critical
exponent estimated from the temperature dependence of the
sublattice magnetization measured by P NMR at 9.4\,MHz is consistent
with universality classes of three-dimensional spin models. The isotropic and
axial hyperfine couplings between the P nuclei and V spins are
Oe/ and Oe/, respectively. Magnetic susceptibility
data above 6.5\,K and heat capacity data above 4.5\,K are well described by
quantum Monte-Carlo simulations for the Heisenberg model on the square lattice
with \,K. This value of is consistent with the values obtained
from the NMR shift, and electron spin resonance (ESR) intensity
analysis. Doping ZnVO(PO with non-magnetic Ti leads to a
marginal increase in the value and the overall dilution of the spin
lattice. In contrast to the recent \textit{ab initio} results, we find neither
evidence for the monoclinic structural distortion nor signatures of the
magnetic one-dimensionality for doped samples with up to 15\% of Ti. The
N\'eel temperature decreases linearly with increasing the amount of
the non-magnetic dopant.Comment: 13 pages, 12 figures, 2 table
Kardar-Parisi-Zhang universality in first-passage percolation: the role of geodesic degeneracy
We have characterized the scaling behavior of the first-passage percolation (FPP) model on two types of discrete networks, the regular square lattice and the disordered Delaunay lattice, thereby addressing the effect of the underlying topology. Several distribution functions for the link-times were considered. The asymptotic behavior of the fluctuations for both the minimal arrival time and the lateral deviation of the geodesic path are in perfect agreement with the Kardar-Parisi-Zhang (KPZ) universality class regardless of the type of the link-time distribution and of the lattice topology. Pre-asymptotic behavior, on the other hand, is found to depend on the uniqueness of geodesics in absence of disorder in the local crossing times, a topological property of lattice directions that we term geodesic degeneracy. This property has important consequences on the model, as for example the well-known anisotropic growth in regular lattices. In this work we provide a framework to understand its effect as well as to characterize its extent.We acknowledge fruitful conversations with E. Korutcheva. This work has been supported by MINECO/FEDER (Spain/EU) grants FIS2015-66020-C2-1-P and FIS2015-69167-C2-1-P
Charge Dynamics in Cuprate Superconductors
In this lecture we present some interesting issues that arise when the
dynamics of the charge carriers in the CuO planes of the high temperature
superconductors is considered. Based on the qualitative picture of doping, set
by experiments and some previous calculations, we consider the strength of
various inter and intra-cell charge transfer susceptibilities, the question of
Coulomb screening and charge collective modes. The starting point is the usual
p-d model extended by the long range Coulomb (LRC) interaction. Within this
model it is possible to examine the case in which the LRC forces frustrate the
electronic phase separation, the instability which is present in the model
without an LRC interaction. While the static dielectric function in such
systems is negative down to arbitrarily small wavevectors, the system is not
unstable. We consider the dominant electronic charge susceptibilities and
possible consequences for the lattice properties.Comment: 14 pages, 15 figures, latex, to be published in "From Quantum
Mechanics to Technology", Lecture Notes in Physics, Springe
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