16,212 research outputs found
Local Electronic Structure and High Temperature Superconductivity
It is argued that a new mechanism and many-body theory of superconductivity
are required for doped correlated insulators. Here we review the essential
features of and the experimental support for such a theory, in which the
physics is driven by the kinetic energy.Comment: 8 Pages Latex. For the Proceedings of HTS99, Miami, FL, Jan. 199
Stripe phases in high-temperature superconductors
Stripe phases are predicted and observed to occur in a class of
strongly-correlated materials describable as doped antiferromagnets, of which
the copper-oxide superconductors are the most prominent representative. The
existence of stripe correlations necessitates the development of new principles
for describing charge transport, and especially superconductivity, in these
materials.Comment: 5 pp, 1 color eps fig., to appear as a Perspective in Proc. Natl.
Acad. Sci. US
Enhancement of pairing in a boson-fermion model for coupled ladders
Motivated by the presence of various charge inhomogeneities in strongly
correlated systems of coupled ladders, a model of spatially separated bosonic
and fermionic degrees of freedom is numerically studied. In this model, bosonic
chains are connected to fermionic chains by two types of generalized Andreev
couplings. It is shown that for both types of couplings the long-distance
pairing correlations are enhanced. Near quarter filling, this effect is much
larger for the splitting of a pair in electrons which go to the two neighboring
fermionic chains than for a pair hopping process. It is argued that the pairing
enhancement is a result of the nearest neighbor Coulomb repulsion which tunes
the competition between pairing and charge ordering.Comment: 7 pages, 7 eps figures, enlarged version accpeted in Phys. Rev.
The three-dimensional BF Model with Cosmological Term in the Axial Gauge
We quantize the three-dimensional -model using axial gauge conditions.
Exploiting the rich symmetry-structure of the model we show that the
Green-functions correspond to tree graphs and can be obtained as the unique
solution of the Ward-Identities. Furthermore, we will show that the theory can
be uniquely determined by symmetry considerations without the need of an action
principle.Comment: one reference added, transmission errors correcte
A comparison of the finite difference and finite element methods for heat transfer calculations
The finite difference method and finite element method for heat transfer calculations are compared by describing their bases and their application to some common heat transfer problems. In general it is noted that neither method is clearly superior, and in many instances, the choice is quite arbitrary and depends more upon the codes available and upon the personal preference of the analyst than upon any well defined advantages of one method. Classes of problems for which one method or the other is better suited are defined
Landau theory of phase separation in cuprates
I discuss the problem of phase separation in cuprates from the point of view
of the Landau theory of Fermi liquids. I calculate the rate of growth of
unstable regions for the hydrodymanics and collisionless limit and, in presence
of long range Coulomb interactions, the size of these regions. These are
analytic results valid for any strength of the Landau parameters.Comment: RevteX, preprint ITP (1994
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